Title,text
Research on Airborne Noise of Battery Electric Vehicles Based on Transfer Path Analysis,"With the popularity of battery electric vehicles, the engine of the vehicle disappears, so the problem of road noise in cars is becoming more and more prominent. Road noise into the car can be divided into structure-borne noise and airborne noise, this paper only focuses on the airborne noise above 500Hz, completely ignoring the structure-borne noise. A transfer path analysis model with “Intermediate Response Points” is proposed to accurately represent the transfer path of each airborne noise through the setting of “Intermediate Points”. In the Vehicle Semi-Anechoic Room With 4×4 NVH Chassis Dyno, it is possible to create a working condition with only four tires running, so only the tire noise is considered in this paper. The frequency response function is tested in the Semi-Anechoic Chamber and the operating data is tested in the Vehicle Semi-Anechoic Room With 4×4 NVH Chassis Dyno. The calculations are performed by the Conventional Transfer Path Analysis (CTPA) method and the Operational Transfer Path Analysis (OPA) method, respectively. The total responses were calculated for the three operating conditions of 60 kph, 90kph, and 120kph. Both the CTPA and OPA methods have errors within an acceptable range, but the CTPA method is more accurate. The CTPA method requires testing a large number of frequency response functions, which is time-consuming, while the OPA method is more efficient."
A Practical Approach towards Reducing the HVAC Flow Noise,"Automotive heating ventilating and air conditioning (HVAC) noise is becoming a big concern area as the demand for acoustic comfort increases day by day. Vehicles are manufactured in recent years with quieter powertrain, reduced body leakage, better suspension. The other quieter technologies like electrification, hybridization of vehicle further complicate the whole subject of vehicle cabin noise issue. The HVAC noise is the major noise source inside the cabin. Hence designing a HVAC with very low sound pressure level is quite challenging and poses many difficulties in meeting other basic performances due to certain trade-off while meeting the noise requirement. However in recent years engineers have done extensive research and come up with various feasible and non-feasible solutions in order to reduce the HVAC noise significantly. Most commonly used tools and techniques are numerical simulation and experimental investigation or combined numerical simulation followed by experimental investigation. The present paper describes the way an existing HVAC noise is reduced by extensive experimental investigations. First the HVAC was dismantled and the flow path inside the HVAC was examined in details along with special features. Areas with chances of flow separations, vortices and high turbulent kinetic energy (TKE) were identified. Smoke tracing was also used in order to actually understand that phenomenon. After having deep investigation into those areas, existing HVAC was modified and series of experiments were carried out on this modified HVAC in a semi-anechoic chamber and noise data was captured at different voltages. In all these changes it is always aimed at keeping the airflow same or better than existing HVAC. It is observed that a significant improvement upto 3-4 dB(A) is achieved in overall noise level both at bench level and vehicle level. So this study provides a deeper insight into how HVAC overall noise level is reduced and hence further it can be very well applied at initial stage of design to make the noise level within desired limit."
Rattle and Squeak Investigation on the Interior Components of Automobile,"Automotive rattle and squeak performance is an important factor affecting passenger comfort and perceived quality. In the current work, finite element simulation is developed to analyze the noise potential of adjacent interior components. The statistical “3σ” limit is adopted to assess the rattle risk at adjacent surfaces assuming a Gaussian distribution. The probability expressions about noise registration are derived for the symmetric and asymmetric tolerance zones of an initial nominal gap. Also the acoustical effects of material pairs are tested by stick-slip experiments. Results show modified polypropylene is compatible in frictional contact with itself but expresses noise when paired to adjacent components manufactured of modified acrylonitrile-butadiene-styrene terpolymer under multiple conditions."
Further Study of the Vehicle Rattle Noise with Consideration of the Impact Rates and Loudness,"With the prevalent trend of the pure electric vehicle, vehicle interior noise has been reduced significantly. However, other noises become prominent in the cabin. Especially, the BSR noise generated by friction between parts and the clearance between components become the elements of complaints directly affect the quality of vehicles. Currently, the BSR noises are subjectively evaluated by experts, and the noise samples are simply labeled as ‘qualified’ or ‘unqualified’. Therefore, it is necessary to develop an evaluation model to assess the BSR noise objectively. In this paper, we study the vehicle rattle noise intensively. Several types of rattle noise were recorded in a semi-anechoic room. The recorded signals were then processed in the LMS test lab. to extract the single impact segments. A pool of simulated signals with different impact rates (number of impacts per second) and various loudness was synthesized for analyzation. To verify the universality of the assessment, the in-vehicle background noises were also recorded. The in-vehicle background noises were added to the rattle noise samples to simulate the in-vehicle test environment. Sound metrics were calculated and compared for all the processed samples. Jury assessment with 5 experts were performed to evaluate the rattle noise samples. The correlation between the subjective evaluation and the impact rates as well as sound metrics were studied. Consequently, an objective assessing model for vehicle rattle noise was developed based on the above analysis. This study can be used to assess the rattle noise effectively, and it has bright prospect and great value in engineering."
Development of Tearing Pattern Prediction Model of Laser Scored Region on Invisible Passenger Side Airbag Door,"The tear seam of invisible passenger side airbag door is made on the back of an instrument panel by laser scoring method and it is not shown outside. One of the requirements for the invisible passenger side airbag door is that the airbag module should deploy with no fragmentation at hot, room and cold temperature conditions. In this paper, a section model was developed by detail inspection of tearing phenomena at the laser-scored region. To validate the model, the finite elements of continuous and dot type laser-scored tear seam were built and analyzed in room and cold temperature conditions. Finally, a three-dimensional equivalent shell model was developed and it was proved that the section model and the equivalent shell model could represent well the tearing phenomena of the airbag door. It is expected that the tearing pattern prediction models developed in this study can be used to design the types of laser scoring and the airbag door with the minimum of real deployment tests."
Airflow Simulation Relative to Door-Closing Operability,"Easiness in closing a vehicle door has been often evaluated on a physical vehicle body, and in most cases, has not been fully studied by computer-aided engineering (CAE) in an earlier developing stage. The authors have developed a numerical method for reproducing the behavior of a closing door with a high fidelity. Characteristics of this method are that moving grid is used to reproduce the unsteady air motion caused by closing the door, and that external reaction forces including cabin pressure are coupled with the equation of the door motion to achieve a high fidelity. This method has made it possible to quantitatively evaluate cabin pressure rise and determine minimum door closing velocity, and the method has turned out to be effective."
The Use of in Vehicle STL Testing to Correlate Subsystem Level SEA Models,"For the assessment of vehicle acoustics in the early design stages of a vehicle program, the use of full vehicle SEA models is becoming the standard analysis method in the US automotive industry. One benefit is that OEM's and Tier 1 suppliers are able to cascade lower level acoustic performance targets for NVH systems and components. Detailed SEA system level models can be used to assess the performance of systems such as dash panels, floors and doors, however, the results will be questionable until test data Is available. Correlation can be accomplished with buck testing, which is a common practice in the automotive industry for assessing the STL (sound transmission loss) of vehicle level components. The opportunity to conduct buck testing can be limited by the availability of representative bodies to be cut into bucks and the availability of a transmission loss suite with a suitably large opening. In addition, the temporary fixture used to mount the test structure does not typically provide representative boundary conditions. Boundary conditions are particularly important when the in-vehicle performance is dependent on point connections at hinges / locking mechanisms and flexible seals at the perimeter of the system such as found in doors or lift-gate. In this paper the use of in-vehicle testing on prototype vehicles to assess the STL for the vehicle systems and the SEA models are discussed. Results are presented for a dash panel, floor system and door systems. The measurements are compared with predictions from system level SEA (Statistical Energy Analysis) models of the test systems. It is concluded that subsystem level SEA models can be used to assess the design and correlate well with STL measurements from in-vehicle tests."
Modular door system for side impact safety of motor vehicles,"Side impact collision is one of the toughest safety challenges facing the Auto Industry today. Over thirteen thousand deaths, due to side impact, occurred during 1998 in the United States alone. The main difficulty in designing for side impact collisions is the limited crumple zone between the impacting vehicle and the impacted occupant. This paper presents a proprietary side impact protective door system within the space between the outer skin of a car door and the occupant, which will be as efficient as those already standard in frontal impact. The main objective for introducing the side impact structural system is to maximize energy absorption and minimize injury to the occupant. The developed structural side impact door system acts as a Primary Structure, to be assembled as a truly modular entity. This primary structure is also packaging modular in the sense that it acts as a carrier for the door latch, window regulator and hinges. A variation in safety and structural performance of the developed door system can be achieved by integrating the structural modular door with the vehicle body, using a patented integration system known as Door And Chassis-frame Integration Technology (DACIT). Unlike the traditional doors, that are just suspended weights, the modular door is truly structural and therefore adds strength to the vehicle body. When DACIT is used with the door system the vehicle door becomes part of the overall vehicle structure. The design and development of the side impact modular door system for different size vehicles with and without DACIT will be discussed. In addition, the five stars rating achieved during several side impact crash tests simulating Sport Utility Vehicles hitting mid-size vehicles, equipped with the developed modular door system, will be presented."
Simulation of Warm Forming Assisted Hemming to Study the Effect of Process Parameters on Product Quality,"Current trends in the auto industry requiring tighter dimensional specifications combined with the use of lightweight materials, such as aluminum, are a challenge for the traditional manufacturing processes. The hemming process, a sheet metal bending operation used in the manufacturing of car doors and hoods, poses problems meeting tighter dimensional tolerances. Hemming is the final operation that is used to fasten the outer panel with the inner panel by folding the outer panel over the inner panel. Roll in/out is one of the main quality concerns with hemming, and keeping it under tolerance is a high priority issue for the auto manufacturers. Current hemming process technology, given the mechanical properties of current materials, has reached its saturation limit to deliver consistent dimensional quality to satisfy customers and at the same time meet government standards. Combining warm forming techniques with the traditional hemming process represents a new approach with the potential to overcome the current hemming limitation and to provide a satisfactory solution to all the requirements. The main objective of this research is to understand the effect of localized heating on the final quality in the hemming process by quantifying the influence of key geometrical and process parameters. To achieve this goal, a hemming finite element model, taking into consideration the mechanical properties as function of temperature is developed, and statistical methods to quantify the effect of key variables are employed. As an outcome to this study, the effectiveness of using warm forming techniques to improve hemming quality is assessed for A5182O aluminum, one of the most common used materials for this application."
Comparative Dimensional Quality of Doors: A Benchmarking Study,"A comparative benchmarking study of the dimensional door quality 14 vehicles from Ford, General Motors, Daimler-Chrysler, Toyota, Nissan, BMW, Volvo, and Renault was conducted. Various aspects of the door design, manufacturing, assembly and hanging system were studied. This paper focuses on the dimensional quality of the doors and relates it to the final vehicle quality in terms of gaps and flush as well as customer satisfaction as established by J. D. Power Initial Quality Survey (IQS). For confidentiality reasons, all vehicles in the study are referred to by a coded designation."
Comparative Datuming and Hanging Strategies of Doors: A Benchmark Study,This paper discusses the results of a door benchmark study performed on 14 vehicles. The major focus is on the selection of datums or reference points and its impact on the product quality of the door system. The results indicate that there can be a relationship between datum utilization and quality metrics at any stage in the production process. Specific examples show the impact of various strategies on product performance.
Conductive Plastics Leading Fuel Door Technology,"This paper will discuss, compare, and contrast current materials, designs, and manufacturing options for fuel filler doors. Also, it will explore the advantages of using conductive thermoplastic substrates over other materials that are commonly used in the fuel filler door market today. At the outset, the paper will discuss the differences between traditional steel fuel filler doors, which use an on-line painting process, and fuel filler doors that use a conductive thermoplastic substrate and require an in-line or off-line painting process. After reviewing the process, this paper will discuss material options and current technology. Here, we will highlight key drivers to thermoplastics acceptance, and look at the cost saving opportunities presented by the inline paint process option using a conductive thermoplastic resin, as well as benefits gained in quality control, component storage and coordination."
The Effect of Turbulence on Peak and Average Pressures on a Car Door,"The influence of turbulence on automotive aerodynamics requires further investigation. This paper provides evidence that turbulence directly affects average and peak forces on the front door of a sedan automobile. Wind tunnel and several on-road test conditions were investigated. The results include instantaneous peak and average force coefficients, together with experimental pressure contour plots for a sedan front door. The pressure distribution over the front door of an automobile is important for efficient structural and door seal design. Door pressure distributions vary with flow turbulence characteristics. The results presented in this paper show that turbulent properties of the flow are of importance when investigating flow over the front door of a sedan automobile."
A Robust Solution for a Power-Train Mounting System for Automotive NVH Refinements,"Production variations of a heavy duty truck for its vibrations were measured and then analyzed through an Ishikawa diagram. Noise and Control factors of the truck idle shake were indentified. The major cause was found to be piece to piece variations of its power-train (PT) rubber mounts. To overcome the same, a new nominal level of the mount stiffness was sought based on minimization of a cost function related to vibration transmissibility and fatigue damage of the mounts under dynamic loadings. Physical prototypes of such mounts were proved to minimize the variations of the driver's seat shake at idling among various trucks of the same design. These learning's are useful for design of various subsystems or components to refine the full vehicle-Noise Vibration Harshness (NVH) at the robust design level."
"Structural Diffuse Field Excitation Synthesis by Synthetic Array (SFS-SA), Application to Cars Panels Contributions","Diffuse field or turbulent boundary layer excitations of vehicles are of huge interest in automotive industry. For such excitations reverberation chambers or wind tunnels are necessary, this means high cost experiments. The idea of sound field synthesis to create the acoustic effect corresponding to diffuse field or turbulent boundary layer excitation, is of major interest to reduce drastically the cost of experiments. Originally, techniques based on loudspeakers antenna were used, however, a major difficulty appeared due to driving simultaneously a huge number of sources. To avoid this difficulty a new technique based on synthetic antenna is used here; instead of an array of loudspeakers, just one source is used for scanning the surface where the acoustic field excite the structure. A post processing step, based on plane wave decomposition, is then applied to collected experimental data in order to get the response of the structure or the sound transmission through the structure. Validation of the method is presented by comparing synthetic antenna results to standard measurements of panels sound transmission between two reverberation chambers. The present paper is focusing on panels contributions in a car, leading to an experimental process avoiding the cumbersome masking technique generally used in automotive industry."
Engine Sound Reduction and Enhancement Using Engine Vibration,"Over the past decade, there have been many efforts to generate engine sound inside the cabin either in reducing way or in enhancing way. To reduce the engine noise, the passive way, such as sound absorption or sound insulation, was widely used but it has a limitation on its reduction performance. In recent days, with the development of signal processing technology, ANC (Active Noise Control) is been used to reduce the engine noise inside the cabin. On the other hand, technologies such as ASD (Active Sound Design) and ESG (Engine Sound Generator) have been used to generate the engine sound inside the vehicle. In the last ISNVH, Hyundai Motor Company newly introduced ESEV (Engine Sound by Engine Vibration) technology. This paper describes the ESEV Plus Minus that uses engine vibration to not only enhance the certain engine order components but reduce the other components at the same time. Consequently, this technology would produce a much more diverse engine sound."
The Design of Wind Noise Transducers to Separate Acoustic and Turbulent Pressures,"A four element wind noise transducer has been designed with surface mounted electret microphones in an array pattern which allows for the separate determination of the acoustic and turbulent pressures in wind noise. Three closely spaced transducers, defining an x-y coordinate system, are positioned to determine the velocity and direction of the turbulent flow. A fourth transducer is positioned at a greater distance such that the correlation of the turbulent flow will be diminished while the correlation of the acoustic pressure remains due to its longer wavelength. By averaging the cross-spectral densities of the pressure signals over time, the two contributors to wind noise can be differentiated. In addition, a wireless interface has been designed to minimize the flow disturbance of the transducer array."
Prediction of Automotive Air-Handling System Flow Noise Sound Quality Using Sub-System Measurements,"This paper presents the methodology of predicting vehicle level automotive air-handling system air-rush noise sound quality (SQ) using the sub-system level measurement. Measurement setup in both vehicle level and sub-system levels are described. To assess the air-rush noise SQ, both 1/3 octave band sound pressure level (SPL) and overall Zwicker's loudness are used. The “Sound Quality Correlation Functions (SQCF)” between sub-system level and vehicle level are developed for the specified climate control modes and vehicle segment defined by J.D. Power & Associates, while the Zwicker's loudness is calculated using the un-weighted predicted 1/3 octave band SPL. The predicting models are demonstrated in very good agreement with the measured data. The methodology is applied to the development of sub-system SQ requirement for upfront delivery of the optimum design to meet global customer satisfaction"
A Unique Noise & Vibration Software Tool for Automotive Troubleshooting,"A unique Matlab-based coded engineering software tool (Time-Frequency Analyzer Core®) was developed that allows users to process acquired time data to help in identifying sources and paths of noise and vibration (in the experience of the authors). The Time-Frequency Analyzer Core (TFAC) software does not replace commercial off the shelf software/hardware NV specific tools such as modal analysis, ODS, acoustic mapping, order tracking, etc., rather it aims at providing basic, yet powerful data inspection and comparison techniques in a single software tool that facilitates drawing conclusions and identifying most effective next steps. The features and advantages of using this software tool will be explained, along with a description of its application to a few different cases (automotive and off highway/agricultural)."
Operational Determination of Car Window Damping,Wind noise can be a significant event for automotive design engineers. The greenhouse glass plays an important role in the wind noise process. Robust estimates of the greenhouse glass damping are necessary for both understanding and modeling the role of the glass in the wind noise process. One unanswered question is whether the aerodynamic loads affect the window glass damping. To make this determination a method to assess the operational damping is required. The civil engineering community uses the random decrement technique to assess operational damping due to wind loads. The random decrement technique has been shown to be a normalized autocorrelation function. In this paper the damping is estimated directly from the autocorrelation function. In the first section the relationship between the damping and autocorrelation function is examined for white noise excitation. A single oscillator is examined as the first case. Extension to higher modal densities is discussed. Finally application to a car window is presented. The window results were limited by signal to noise problems.
An Experimental Study of Mechanism of Body Panel Vibration in Booming Noise Reduction of Passenger Vehicles,"In a typical passenger vehicle, there can be different types of noises generated which are broadly categorized as Interior Noise and Exterior Noise. The interior noise sources can be further classified into noises which can be Structure Borne or Air Borne. One of the major sources of both structure borne and airborne noise generation is the powertrain of the vehicle. The structure-borne noise and vibrations generated from the powertrain is usually transferred to the vehicle body through its attachment points to the body and the powertrain driveline. These induced body vibrations can sometimes cause the acoustic cavity of the passenger cabin to go into resonance which results in an annoying and disturbing noise for the passengers, called Booming Noise. Very often, one or more than one vehicle body panels show a dominant contribution in inducing this acoustic cavity resonance. In this research, the backdoor of the selected passenger cars were identified to be one of the primary contributors in causing the booming noise phenomena. The objective of this research was to study the mechanism of the contribution of backdoor towards booming noise in these hatchback style passenger vehicles. The study was carried out on three differently styled hatchbacks namely Model A, Model B, and Model C. The study of the mechanism behind this contribution was carried out in three phases. The first phase included the response measurements of the individual grid points created on the backdoor which were excited using a low frequency sound source. In the second phase, a computer model of the grid structure of the backdoor was created and the response measurements obtained were superimposed on the geometry model to identify the modal parameters of the backdoor. The identification of the modal parameters helped in understanding the modal behavior of the backdoor which is causing the acoustic resonance of the cabin cavity thus creating the booming noise phenomena. In the third phase, in cabin acoustic measurements were carried out during vehicle acceleration tests and the results were correlated with the modal parameter data. This helped in identification of the dominant modal frequencies to be targeted for further design improvements during concept & vehicle design stage."
The Effects of Unsteady Flow Conditions on Vehicle in Cabin and External Noise Generation,"A vehicle driving on the road experiences unsteady flow conditions which are not generally reproduced in the development environment. This paper investigates the potential importance of this difference to aeroacoustics and hence to occupant perception and proposes a methodology to enable better ranking of designs by taking account of wind noise modulation. Two approaches of reproducing the effects of unsteady wind on aeroacoustics were investigated: an active wind tunnel Turbulence Generation System (TGS) and a quasi-steady approach based on measurements at a series of fixed yaw angles. A number of tools were used to investigate the onset flow and its impacts, including roof-mounted probe, acoustic heads and surface microphones. External noise measurements help to reveal the response of separate exterior noise sources to yaw. The noise experienced by the driver or passenger ear facing the side-glass is dominated by increased sound pressure levels when the adjacent side-glass is the leeward side of the vehicle with some non-linear effects as leeward yaw produces first accelerated flow and then separation. In part because of non-linearity in response to yaw, a challenging parameter for a wind tunnel simulation of dynamic yaw is achieving a wide enough variation in yaw angle and this work suggests that considering an appropriate range of yaw angles is more important than capturing the dynamics. In terms of passenger perception, the most important effect of a time-varying onset flow was demonstrated to be the modulation of wind noise rather than the increase in time-averaged cabin noise. For the case considered, at 130 km/h, the impact of wind-noise modulation was found to be equivalent to an extra 1-2 dBA in terms of passenger perception, while the increment in time-averaged cabin noise would be only 0.2 dBA."
Daimler Aeroacoustic Wind Tunnel: 5 Years of Operational Experience and Recent Improvements,"Since 2013 the new Daimler Aeroacoustic Wind Tunnel (AAWT) is in operation at the Mercedes-Benz Technology Center in Sindelfingen, Germany. This construction was the second stage of a wind tunnel center project, which was launched in 2007 and started with the climatic wind tunnels including workshop and office areas. The AAWT features a test facility for full-scale cars and vans with a nozzle exit area of 28 m2, a five-belt system, and underfloor balance to measure forces with best possible road simulation. With a remarkable low background noise level of the wind tunnel, vehicle acoustics can be investigated under excellent conditions using high-performance measurement systems. An overview is given about the building and the design features of the wind tunnel layout. The aerodynamic and aeroacoustic properties are summarized. During the first years of operation, further improvements regarding the wind tunnel background noise and vehicle handling were made. Changes in the surface of the contraction and the reduction of rough surfaces in the test section reduced the self-noise of the wind tunnel. For the standard test section configuration (used for daily operation) with smooth center belt, an overall sound pressure level of 57.2 dB(A) could be achieved, for a further optimized configuration with taped gaps and covered shutters and belts even 55.2 dB(A) were measured. Since the manual ride height adjustment of a vehicle in the test section showed to be very time-consuming, a new automatic ride height measuring system was developed. It significantly reduces the setup time before the first measurement. For the rising demands to document surface changes after a test campaign, a separate room for 3D surface scanning was already provided in the workshop area. The technical layout could only be finished with delay. Now the room houses a frontal area measurement system, vehicle lifts, and a robot for 3D surface scanning. This paper describes these new features and reports about the experiences of the first years of operation."
Surface treatment to reduce squeak noise in vinyl parts,"It is a common practice of automotive industry to avoid dynamic contact between two surfaces with similar roughness for plastics and interior trim parts. That means reduce the friction and, consequently the squeak noise to the minimum level to meet zero noise level. Unfortunately, for design or economics reasons, that is not possible for some applications and a very disturbing noise may bother the costumer. A material incompatibility leads to an acute noise when two similar surfaces have relative movement due to multiple adherences between the surfaces, that is called stick-slip phenomenon. To characterize this noise, a Squeak and Rattle Evaluation testing should be performed in the worst case condition over the life of the vehicle. As a result, a scale of Risk Priority Number (RPN) provides a pass/fail judgement to implement any improvement required to address the issue. There are several ways to avoid this phenomenon during the product development: applying lubricants, tapes, coatings, material change or surface treatments. To solve this kind of undesirable user experience, an anti-squeak treatment was developed in water base using polymeric material, applied in a process similar to coating and cured thereafter by heat. The concept of this anti-squeak treatment is to reduce surface tension and the resistance of relative movement when fractioning similar material that leads to a reduction of noise, consequently. The aim of this paper is to show how this surface treatment can reduce the noise level related to material similarity, applying this into a vinyl surface, with no changes in mechanical properties and no need to run a new design verification plan. In the present study, it could be observed a reduction from 10 RPN to 2 RPN, related to an improvement from material match critical to material match in order. This corresponds to a customer satisfaction perception improvement from material audible annoying noise caused by stick- slip expected to not perceived noise."
Designing In-Cab Sound of Vehicles as per the Customer Driving Pattern on Roads,"Vehicle refinement from point of view reduction in its Noise, Vibrations and Harshness (NVH) affects customer’s buying decision and it also directly influences his/her driving experience on road at different speeds. Customer voice, however, indicates that a traditional process of developing design solutions is not aligned with the customers’ expectations. Traditionally the load cases for NVH development are focused only on quietness of passengers’ cabin at idling and in 3rd gear wide open throttle cruising on smooth roads. In reality, the Driver of a premium sedan car or a Sports Utility Vehicle (SUV) or a Compact Utility Vehicle (CUV) expects something different than merely the low sound pressure level inside the cabin. His/her driving pattern over a day plays a crucial role. A vehicle-owner wishes to balance various attributes of the in-cab sound and tactile vibrations at a time. A single value Customer-Voice-Index (CVI) is developed here based on study of critical drive load cases faced by common customers classified with C: Critical to customer perception; O: Occurrence of each drive load case throughout running of the vehicle and D: Duration of each load case. Cost to Benefit Ratio of various design solutions then could be evaluated effectively in a vehicle by monitoring its CVI. This is demonstrated here on a new SUV to give the desired sound character of the vehicle with low cost solutions and thus make the customers fall in love with it during cruising on highways at high speeds."
Low Frequency In-Cab Booming Noise Reduction in the Passenger Car,"In-cab booming noise is low frequency (20 Hz∼300 Hz) phenomenon excites the cabin structure, which occurs mainly due to excitations from the powertrain, exhaust system, road input, etc. Annoyance due to booming noise affects the In-cab sound quality, which results in passenger discomfort. A diesel passenger car observed booming noise issue when operated at stationary as well as dynamic run-up conditions. In order to increase passenger comfort, experimental root cause analysis conducted on the vehicle to investigate the dominant sources for the cavity boom. Exhaust hanger and one of the engine mount identified as major reason for the booming noise in the cabin. A detailed study was carried out on dynamic property optimization of rubber hanger and possibility to relocate the hanger to improve the vibration transmissibility. Operational measurements conducted on vehicle by attaching finalized exhaust mount to confirm the significant booming noise reduction in the cabin."
Investigation of Cabin Noise while Accelerating on Low Mu Track through Simulation Approach Using Full Vehicle ADAMS/Car Model,"Cabin noise is a significant product quality criteria which enables the customers for product differentiation. There are various sources of cabin noise such as wind, structures(panels), engine, suspension, tire and roads. During product development phase, extensive tests has been conducted to improve vehicle dynamics behavior on various climatic conditions. One such test is accelerating vehicle on low mu or icy surface. While performing acceleration manoeuvre (tractions) on a low mu tracks, Cabin noise with source identified from front underbody & low tractive torque build up is reported. This undesirable behavior may occur due to following reason (1) Excitation of coupled modes between suspension and powertrain which induces torque fluctuation. (2) Transmissibility of various subsystem can be the reason for above problem statement. (3) Poorly chosen tire compounds and design leads to fluctuation in torque. A detailed simulation based study using ADAMS/CAR has been performed to assess the contribution of various full vehicle sub-systems, primarily suspension & powertrain sub-system towards the said problem statement. The dynamic interaction between road, suspension, powertrain and BIW has been is the focus of study both in time and frequency domain. This simulation helped understand the factor effects and contribution levels and correlates well with the subjective feel observed on the physical vehicle on low-mu track. This model has been further used to provide design recommendation on the compliance parameters to overcome the issue at hand. Test has been conducted with recommended tire grip properties and suspension bushing parameters which lead to reduction in cabin noise"
Design of Super Silent Enclosure for Diesel Genset Using Statistical Energy Analysis (SEA) Technique,"Diesel engine generators are commonly used as a power source for various industrial and residential applications. While designing diesel generator (DG) enclosures requirements of noise control, ventilation and physical protection needs to be addressed. Indian legislation requirement demands DG enclosure insertion loss (IL) to be minimum 25 dB. However for certain critical applications like hospitals, residential apartments customer demands quiet DG sets than the statutory limits. IL targets for such application ranges between 35-40 dB. The objective of this paper is to develop methodology to design ‘Super Silent’ enclosure with IL of 35 dB by Statistical Energy Analysis (SEA) approach for small capacity DG set. Major challenge was to achieve IL of 35 dB with single enclosure and making use of SEA technique for small size enclosure wherein modal densities is very less. Major airborne noise sources like engine, radiator fan and exhaust were modelled by capturing noise source test data. Structure-borne sources like panel vibrations were also modelled via vibration measurements. Noise control treatments (NCT) were sculpted using BIOT parameters. The predicted sound levels for an existing DG enclosure model were validated with its test data to ensure correctness of SEA model. Further critical noise paths identification and ranking was done through simulation. Based on results of above step, modifications were suggested on NCT, louvers, baffles, ducts and muffler to arrive at optimized enclosure. Proto for optimized enclosure was tested. Test showed IL of 35.5 dB against predicted IL of 35 dB showing very good correlation."
Computational Aeroacoustics Based on a Helmholtz-Hodge Decomposition,"Using existing aeroacoustic wave equations, we propose a general hybrid aeroacoustic method, based on compressible flow data. By applying the Helmholtz-Hodge decomposition on arbitrary domains, we extract the incompressible projection (non-radiating base flow) of the compressible flow velocity by solving the vector valued curl-curl equation with the vorticity as forcing term. The resulting vortical flow part is used for computing the acoustic source term. This method maintains the favorable properties of the hybrid aeroacoustic method, while still considering acoustic feedback on the flow field."
Numerical Design of Loudspeaker Systems in a Car Cabin,"These days loudspeaker systems in vehicles are gaining more and more of importance. Usually quite a few speakers are installed and driven in combination in order to obtain a convincing sound environment for the occupants/customers. Sometimes even a 3D sound experience shall be reached, where up to 20 loudspeakers might become necessary. No doubt that such a number of speakers and their proper placement in the car cabin is a rather challenging task, leading to extensive measurements in different cabin environments. In the current contribution, it is suggested to simulate the scenario by means of specially combined computer models. These allow not only a rather economic possibility to investigate different changes/variants without expensive new setups but also an additional gain of knowledge. For the numerical representation of the loudspeaker system a multiphysics approach is needed, namely physical aspects of electromagnetics, structural dynamics, and acoustics have to be considered and combined. Doing so, the different fields might be accounted for by models obeying different levels of detail, where the spectrum might reach from simple 1D approaches to highly detailed 3D models. In view of this, different methodologies such as the finite element method, the boundary element method or energy based formulations need to be coupled. In the current contribution a methodology for the numerical design of loudspeaker systems is developed and discussed by means of representative examples."
Correlation Analysis of Interior and Exterior Wind Noise Sources of a Production Car Using Beamforming Techniques,"Beamforming techniques are widely used today in aeroacoustic wind tunnels to identify wind noise sources generated by interaction between incoming flow and the test object. In this study, a planar spiral microphone array with 120 channels was set out-of-flow at 1:1 aeroacoustic wind tunnel of Shanghai Automotive Wind Tunnel Center (SAWTC) to test exterior wind noise sources of a production car. Simultaneously, 2 reference microphones were set in vehicle interior to record potential sound source signal near the left side view mirror triangle and the signal of driver’s ear position synchronously. In addition, a spherical array with 48 channels was set inside the vehicle to identify interior noise sources synchronously as well. With different correlation methods and an advanced algorithm CLEAN-SC, the ranking of contributions of vehicle exterior wind noise sources to interested interior noise locations was accomplished. The results demonstrate that the advanced deconvolution algorithm CLEAN-SC has significant improvement against limitations of spatial resolution and dynamic range of conventional Beamforming technique. It has great potential for vehicle wind noise transmission path analysis and wind noise optimization work in the wind tunnel. In addition, Correlation analysis result of interior and exterior noise sources using virtual and real reference microphones was compared and discussed as well."
An Analysis on Automotive Side Window Buffeting Using Scale Adaptive Simulation,"Automotive window buffeting is a source of vehicle occupant’s discomfort and annoyance. Original equipment manufacturers (OEM) are using both experimental and numerical methods to address this issue. With major advances in computational power and numerical modelling, it is now possible to model complex aero acoustic problems using numerical tools like CFD. Although the direct turbulence model LES is preferred to simulate aero-acoustic problems, it is computationally expensive for many industrial applications. Hybrid turbulence models can be used to model aero acoustic problems for industrial applications. In this paper, the numerical modelling of side window buffeting in a generic passenger car is presented. The numerical modelling is performed with the hybrid turbulence model Scale Adaptive Simulation (SAS) using a commercial CFD code. While the acoustic generation is modelled by solving compressible Navier-Stokes equation, integral method Ffowcs-Williams & Hawkings (FWH) is used to model acoustic propagation in the computational domain. Certain investigation on the influence of rear view mirror (RVM) & divide pillar on buffeting noises are analyzed using a few flow and spectral techniques. Differences in the noise levels between front and rear window buffeting are also investigated. A 3D-cavity test model is considered to validate the modelling methodology. Investigations have shown the installation of a divide pillar on window have significantly minimized noise levels and appendages like the glass mounted RVM have a minimizing effect on the buffeting intensity. Also the noise levels of rear window buffeting are found to be higher than front window buffeting. Modelling window buffeting using a SAS model have shown to be a reliable and computationally less expensive option. The investigations using spectral technique like Fast Fourier Transform (FFT) band analysis gave a better insight in to buffeting problem."
Acoustic Enclosure Optimization for a Higher Capacity Diesel Generator Set Using Statistical Energy Analysis (SEA) Based Approach,"Diesel powered electric generators are used in a variety of applications, such as emergency back-up power, temporary primary power at industrial facilities, etc. As regulatory and customer requirements demand quieter designs, special attention is given to the design of acoustic enclosures to balance the need of noise control with other performance criteria like ventilation and physical protection. In the present work, Statistical Energy Analysis (SEA) approach augmented by experimental inputs is used to carry out Vibro-acoustic analysis of an enclosure for higher capacity Diesel generator set. The exterior sound radiated from an enclosed generator is predicted and further enclosure is optimized for an improved sound-suppression. The airborne sources such as engine, alternator, radiator fan and exhaust are modelled explicitly using experimental noise source characterization. Structure borne inputs are also captured in the test for improving modelling accuracy. The vibroacoustic performance of the enclosure and sound absorbers are modelled through Biot parameters and experimentally validated with a good agreement between test and simulated results within 2 dB for overall levels. Further, path contribution and sensitivity analysis has been done on base enclosure to find out major contributors to exterior radiated noise. Optimization is done using parameters like: noise path modifications (ducts, partitions), leakage minimization and acoustic louver designing based on preceding analysis results. Optimized enclosure has resulted in 3 dB reduction in overall noise level"
Sound Quality Evaluation of a Brake and Clutch Pedal Assembly used for Automotive Applications,Sound Quality (SQ) of brake and clutch pedal assembly plays an important role in contributing to vehicle interior noise and perception of sound. Quiet operation of brake and clutch units also reflects the vehicle built and material quality. Noise emitted from these sub-assemblies has to meet certain acceptance criteria as per different OEM requirements. Not much work has been carried on this over the years to characterize and quantify the same. An attempt has been made in this paper to study the sound quality of brake and clutch pedal assemblies at component level and validate the same by identifying the parameters affecting SQ. Effect on noise at different environmental conditions was studied with typical operating cycles in a hemi-anechoic chamber. The effect of sensor switches integrated within the clutch and brake pedal on sound quality is analyzed. It is found that the operating characteristics of switches drives the noise and SQ. Wavelet analysis was carried out to correlate loudness sound quality metric with time-frequency amplitude modulations. Jury evaluation was performed to correlate subjective to objective data. Structural modifications were then suggested to improve the perception of sound. Significant improvement in the brake and clutch pedal assembly sound quality was achieved in product development with marginal impact on cost.
A Study on the Vehicle Body Effect on Brake Noise,"Creep groan noise occurs in a just moving vehicle by the simultaneous application of torque to the wheel and the gradual release of brake pressure in-vehicle. It is the low frequency noise giving the driver a very uncomfortable feeling. Recently, the field claims regarding the creep groan noise are increasing. So far, creep groan noise has been improved by means of chassis modification the transfer system. But vehicle body the response system does not. In this paper, the effect between vibration characteristics of vehicle body, creep groan noise was analyzed. Then presented analysis method for vehicle body effect regarding creep groan noise."
C-17 Cargo Ramp and Door Automated Drilling & Fastening System - Project Overview,"To further reduce airframe costs associated with fastener installation, an Automated Drilling & Fastening System (ADFS) has been implemented on the C-17 Program to enhance current Mold Line attachment processes. The ADFS will automate up to 90% of all Cargo Ramp and Door Mold Line fastener installations. Implementation of the C-17 ADFS captures a five goal technological approach identified at project onset: 1) Increase the use of automated drilling and fastening equipment, 2) System shall be Numerically Controlled, 3) High speed drilling techniques shall be used, 4) Minimize the use of current tooling, and 5) Design the system to use components common to other Boeing drilling & fastening machines."
Mechanical and Structural Aspects of the C-17 Cargo Ramp and Cargo Door ADFS,"The cargo ramp and cargo door are two major C-17 components that are built in St. Louis, MO and shipped by rail for final assembly in Long Beach, CA. A major portion of the total build time for the ramp and door assemblies consisted of the hand installation of approximately 16,000 moldline fasteners and 19,400 moldline fasteners, respectively, attaching the skin to the substructure. In addition, several thousand fasteners are also installed in the floor sections of the ramp and door. A major cost savings opportunity existed to reduce the cost of the ramp and door assemblies by automating the installation of these fasteners. Boeing-St. Louis contracted Brotje Automation of Wiefelstede, Germany to design and build an automated drilling and fastening system (ADFS). Automation is expected to reduce cost by reducing the time required to build the ramp and door assemblies. In addition, automation is expected to improve fastener hole quality and fastener installation quality. Another important reason for undertaking this project was to enable Boeing-St. Louis to strengthen its position as an industry leader and innovator in aerospace manufacturing. This paper describes the mechanical and structural challenges (associated with hoisting and supporting the assemblies) that were overcome to implement this initiative."
A Direct Method for Designing Fuel Filler Door with Torsional Spring,"A direct method is developed for designing a vehicle fuel filler door with torsional spring. The design parameters include the door's geometrical parameters and spring dimensions. The design requirements are based on the finger force curve during closing and opening, and the bending stress in the spring. An example is included to demonstrate the effectiveness of the new method."
An Ultra-Light Thin Sliding Door Design - A Multi-Product Multi-Material Solution,"Sliding door designs are applied to rear side doors on vans and other large vehicles with a trend towards dual sliding doors with power operation. It is beneficial for the vehicle user to reduce the weight of and space occupied by these doors. Alcoa, in conjunction with Ford, has developed a multi-product, multi-material-based solution, which significantly reduces the cost of an aluminum sliding door and provides both consumer delight and stamping-assembly plant benefits. The design was successfully demonstrated through a concept readiness/technology demonstration program. The key findings of the joint effort demonstrated: Reduced system cost through parts reduction/consolidation and associated reduction of stamping and joining/assembly operations, gauge reduction and optimized material utilization Reduced thickness of the door by over 60mm and weight reduction by over 11kg, Equivalent functional performance to the current steel door Manufacturability using robust processes at desired quality and reliability levels. Improved quality and reliability of assembling the door hardware, which significantly improved serviceability over traditional designs. The basic door design concept is also applicable to other types of doors."
Integrated Test Platforms: Taking Advantage of Advances in Computer Hardware and Software,"Ongoing hardware, software, and networking advances in low-cost, general-purpose computing platforms have opened the door for powerful, highly usable, integrated test platforms for demanding industrial applications. With a focus on the automotive industry, this paper reviews the pros and cons of integrated test platforms versus single-purpose and stand-alone testers. Potential improvements in in-process testing are discussed along with techniques for effectively using such testing to improve daily production quality, to maintain high production rates, to avoid unplanned downtime, and to facilitate process and product improvements and refinements through the use of monitoring, data collection, and analysis tools."
Optimal Design of Panel Reinforcing Material Using Practical Measurement Technique,"Expandable reinforcing material such as that used for the outer panel of a door has been used to compensate for the lack of stiffness in automotive body panels. This material can improve panel stiffness and reduce vibration that causes radiated noise. Material properties in practical use have generally been evaluated by sensory methods. These properties, however, have not been sufficiently quantified to optimally design reinforcing material. We have developed evaluation methods aimed at ensuring reinforcement and also at reducing vibration and deformation in a panel. By employing these evaluation methods along with simulation of a material's basic properties, we are able to achieve the optimal design of materials for outer body panels."
Quantitative Assessment of Cosmetic and Structural Quality in Automotive Outer Body Panels Using ARAMIS Stereo Photogrammetry System,"The methodology described enables high accuracy in the measurement of static and dynamic stiffness and dent resistance. Among the parameters being evaluated are: stiffness and dent resistance of the automotive outer body assembled panels – under both static and dynamic loading and the effect of the stiffening features in the panel shape, upon its deformation characteristics under dynamic excitation and dynamic wave propagation following slow projectile impact. This methodology will help part and process designers to correctly position and manufacture outer and inner body features like door handle embossment shape and location, feature lines, lamp and mirror embossments, hemming lines and side bar locations. Measurements are carried out using the stereo photogrammetry system ARAMIS – a fast and cost effective tool with a high accuracy of displacement measurement in both static and dynamic conditions. Measurements were performed in real time related to the phase of elastic wave generated by projectile impact. Parameters of the elastic wave were defined using laser displacement sensors and accelerometers with a linear accuracy of 0.5 μm."
Visualization and Classification of Strategy for Entering Car,"This paper proposes a method for visualizing and classifying the variation in the motions of a person when entering a passenger vehicle. Entering behaviors vary greatly between individuals, especially if the vehicle door is designed to have large clearance. The present study was conducted with the aim of supporting the design process of seats and front doors by visualizing possible variations of entering motions using a motion database, rather than calculating a single representative movement. The motion database is consist of different motions caused by various seats, and the motions are classified by mapping them into two-dimensional plane according to the similarities between them. A representative entering motion for a clustered motion strategy group is synthesized and visualized on the 2D distribution plane by interpolating existing motions in the database."
Development and Application of High-Strength Steel for Auto Outer Panel in Baosteel,"The characteristics of China's automotive steel sheets and high strength steels (including bake-hardening, high strength IF and isotropic steel) developed recently by Baosteel for automotive outer panels are briefly reviewed. Among these steels, bake-hardening (BH) steel is often used to make outer panel parts, such as hoods, decklids, and front and rear doors. In this paper, we present results from an investigation of the effect of baking process (temperature and time) on the bake hardening index value of BH220 steel, and through evaluation of tensile specimens cut from a production hood and simulated part. The results show that BH value is more than 30 MPa when the baking time is more than 2 minutes (at a temperature of 170°C) or the baking temperature is more than 90°C (for baking time of 20 minutes). Measurements on an actual hood and simulated part showed that baking has no effect to enhance the yield strength of the panel, but it can enhance the dent resistance. One needs to consider other factors when using the empirical equation (DR∝K×ta×YS) to evaluate dent resistance of automotive panels."
Advanced High-Strength Steels and Hydroforming Reduce Mass and Improve Dent Resistance of Light Weight Doors In UltraLight Steel Auto Closures Project,"In May 2000, the UltraLight Steel Auto Closure (ULSAC) Consortium unveiled a lightweight frameless steel door design that achieves 42 percent weight savings over the average benchmarked (1997 model year vehicles) frameless door and 22 percent savings over the lightest benchmark, a framed door. ULSAC was commissioned by this international consortium of 31 sheet steel producers to assist their automotive customers with viable lightweighting steel solutions. The ULSAC design and engineering team, Porsche Engineering Services, Inc. (PES), Troy, Michigan USA, accomplished this significant weight savings by using high and ultra high strength steels, combined with technologies such as tailored blanks and hydroforming. The door outer panel of this first round of demonstration hardware is made of stamped 0.7 mm Bake Hardenable (BH) 260 sheet steel. During the design and development of the ULSAC frameless door, the ULSAC Consortium evaluated further mass reduction, using sheet hydroforming for the door outer. Consequently, the ULSAC Validation Phase continued beyond May 2000 with sheet hydroforming process development for the door outer as a means to compile practical research documentation for this developmental process with mass reduction potential. Door structures were successfully manufactured with 0.6 mm Dual Phase (DP) 600 hydroformed steel outer panels achieving additional weight savings."
Economic Analysis of Two Different Door Architectures,"In the past, materials selection for automotive components has been managed on a part-by-part basis. As a result, the economics of these selections have often been reduced to comparing material price/property ratios, rather than technological options. More recently, the debate around modular designs and their advantages and disadvantages has shifted the emphasis towards a higher level viewpoint that deals with more complex systems. This approach provides the opportunity to search for new combinations of product architecture and materials that may exploit specific material advantages better than the classic part-by-part replacement. This paper presents the results of an economic analysis for two different door designs. The door designs differ both with regards to their product architectures and with regards to the materials they employ. The economic analysis considers the following process steps: parts fabrication, subassembly, paint, and final assembly (trim) for two production scenarios. The case study reveals several findings. First, the analysis concludes that both door designs offer a potential economic advantage depending on the final production volume. Specifically, the conventional design is considered more appropriate for high volume production, whilst the alternative design is more cost effective at production volumes typical of niche and derivative vehicles. Second, since the choice of design architecture has an influence on all sub systems, meaningful comparisons between the architectures may be made only through the adoption of comprehensive cost models. For example, the case study demonstrates that the choice of certain product architectures can help mitigate disadvantages caused by higher input material costs. Finally, the case study finds that the cost savings from ‘commonization’ of components vary depending on the base production volume."
Open Bay Door Analysis Process for Hubble Space Telescope Servicing Mission 3B,"During Servicing Mission 3B (SM3B) for the Hubble Space Telescope (HST) the Power Control Unit (PCU) will be replaced. The PCU was not originally designed to be replaced on orbit but was later identified as having the capability of being removed and replaced on orbit. The PCU has many connectors and bolts, some of which are difficult for the astronauts to reach. Due to the added difficulty, the replacement will take an entire six hour Extra Vehicular Activity (EVA) day. For four of these six EVA hours the door of the Support Systems Module (SSM) Equipment Section (ES) bay where the PCU is found will be open to allow the astronauts access to the PCU and its connectors. This bay, SSM ES Bay 4, also contains the four Power Distribution Units (PDUs), which house the busses, switching, fusing, and monitoring circuits that distribute power to the telescope. These PDUs are attached to the bay door and will be seeing a much colder than normal environment with the door open. The PCU controls power for the entire telescope and therefore when it is replaced all power to the telescope will be turned off. With power removed and the bay door open the PDUs will cool rapidly. In order to be sure that the PDUs remain above their turn-on and operating temperature limits during the change out, a detailed open bay door analysis was conducted. For this analysis a Thermal Synthesizer System (TSS) model was created of Bay 4 and it’s components. The model was used to calculate radiation couplings and heat rates with the bay door open. The FORTRAN code used to analyze the Servicing Mission timeline was modified and the new radiation couplings and heat rates added. This paper deals with the creation of the detailed TSS model as well as the modifications made to the timeline code in order to run the analysis. It will also present the temperature predictions for the PDUs during the PCU change out."
Passive Sensing of Driver Intoxication,"A sensor that passively monitors the driver for intoxication has been demonstrated. The driver's blood alcohol concentration (BAC) is obtained by sensing alcohol and CO2 in air drawn from the vehicle cabin. With a legally drunk driver, the steady state alcohol concentration can be as low as 0.3 ppm, even with the doors and windows closed. The sensor uses infrared transmission to quantify alcohol vapor and CO2. A vapor concentrator increases alcohol sensitivity - an adsorber collects alcohol vapor and releases it as a concentrated burst at 1 minute intervals. A valid measure of driver BAC is ordinarily available 1.5 minutes after the driver gets in. Sensed CO2 must be above a threshold for a valid measurement."
The Truck that Jack Built: Digital Human Models and their Role in the Design of Work Cells and Product Design,"Henry Ford is credited with the invention of the assembly line and for 100 years now we have manufactured high quality cars and trucks. The process to bring cars and trucks into production has seen many changes with the introduction of new technology, however the principle is still the same; designers draw concept designs and engineers transform these designs into functional parts. The first time the engineering community has a real feel for the design and process compatibility is at a physical prototype build. The money invested in the designs and prototype parts alone make the thought of a design change this late in the game, unbearable. The design of the manufacturing process along with product design has embraced virtual tools and digital human models to assess assembly feasibility. The major incentive to utilizing such tools is to reduce costly re-engineering of parts and to decrease prototype costs. Virtual technology allows ergonomists and engineers to perform “virtual builds”. This opens up doors for early ergonomic evaluation on the product design, process and tooling. Digital human models, motion capture technology, and biomechanical evaluations are all critical in performing accurate ergonomic analysis. This paper demonstrates how digital human technology is being utilized every day to drive sound engineering decisions in automotive manufacturing."
Low Gloss ABS Advancements for Automotive Interior Components,"Automotive Original Equipment Manufactures (OEM's) desire interior plastic components being used on consoles, doors, trim areas, and instrument panels to have very low gloss levels. In fact, some OEM's have specified a 2.0 or lower sixty degree Gardner gloss level for most first surface interior components molded in color (MIC) and without paint or a secondary finishing process such as a vinyl wrap. While a trend in the industry is to move toward PP based materials because PP parts are believed to provide lower gloss aesthetics and lower gloss gradients, key features and benefits of ABS products such as dimensional stability, impact, load bearing at elevated temperatures, and scratch resistance, are compromised. Recently, Dow Automotive has developed lower gloss capable ABS resins which also exhibit typical ABS physical and thermal properties. This paper will detail the gloss and gloss gradient advantages of these new low gloss ABS products over a standard talc filled PP material and two traditional ABS products as observed in a glove box outer injection molding trial."
Child Safety via Anti-Trap Proximity Technology,"Sir Galahad™ anti-trap windows prevent injury and death, creating a new standard of care for automotive power closures. NHTSA estimates 500 people, approximately 50% of which are children, are treated in hospital emergency rooms each year for injuries related to power windows [11]. Sir Galahad™ technology is easy to install and works on all applications, independent of window shape or geometry. The system is ideally suited for power windows, sunroofs, tailgates, sliding doors, trunks and any other power closures. This paper describes the design and operation of Sir Galahad™ anti-trap windows, including experience of sensitivity response to both animate and inanimate objects. Also discussed are vehicle installation, performance test results, and competitive performance comparisons."
Tailor-Welded Aluminum Blanks for Liftgate Inner,"Tailor welded steel blanks have long been applied in stamping of automotive parts such as door inner, b-pillar, rail, sill inner and liftgate inner, etc. However, there are few known tailor welded aluminum blanks in production. Traditional laser welding equipment simply does not have the capability to weld aluminum since aluminum has much higher reflectivity than steel. Welding quality is another issue since aluminum is highly susceptible to pin holes and undercut which leads to deterioration in formability. In addition, high amount of springback for aluminum panels can result in dimension control problem during assembly. A tailor-welded aluminum blank can help reducing dimension variability by reducing the need for assembly. In this paper, application of friction stir and plasma arc welded blanks on a liftgate inner will be discussed."
Use of SEA for Vehicle Target Setting and Efficient Realization of Vehicle Acoustic Goals,"Statistical Energy Analysis (SEA) is an established technique for predicting vehicle NVH. Since SEA is more sensitive to certain parameters such as material properties, damping, absorption, and treatment thickness and coverage than to fine details of geometry, using SEA is especially practical and can be particularly advantageous in the early design phase of a vehicle development project. Different concepts for various vehicle subassemblies such as dash, doors, roof, floor, etc., can be effectively evaluated for feasibility at a very early stage in the design process. Such concept studies can prevent design failures and can also be used to improve subassembly NVH target setting. An introduction to SEA and summary of the established use of SEA for vehicle NVH design and development are presented. A proposed methodology for application of SEA to vehicle design is presented, addressing model validation, contribution analysis, target setting, design sensitivity analysis, and optimization for different design concepts and proposed configurations of the vehicle and vehicle subassemblies. A concrete example of an SEA vehicle subassembly model and modeling considerations is presented, followed by a summary and set of conclusions."
A New Approach for Best Fit Assembly Based on the Behaviour of Components,"Best fit assembly is now a widely spread assembly technique that consists in finding an optimal position of measured components in order to get an assembly that fits its tolerance specifications. The rigid body assumption does not apply for compliant assemblies that can be slightly deformed and for which the geometrical variations are cleared by the flexibility of components to be assembled. We are proposing a best assembly process that takes into account through simulation the flexibility of components. Thanks to this more realistic simulation, the best fit application scope can be enlarged and confidently applied. It leads to reduced fitting times for over-constrained parts or interchangeable items, like doors, during assembly integration and in service replacements."
Two-Reference Beam Double-Pulsed Holographic Interferometry with Direct Phase Measurement in Transient Processes Study,"Holographic interferometry has been successfully employed to characterize both static and dynamic behavior of diverse types of structure under stress. Double-exposure pulsed holographic interferometry has been extensively used in performing the vibration analysis and qualitative investigations of deformation of the non-stationary objects. One of the most important advantages of this technique is that it can be used for quantitative measurements of the transient processes (e.g. shock wave propagation). However, in conventional double-pulsed interferometry it is sometimes difficult to get phase information from a single set of holograms. Applying two-reference beam recording set-up to double-exposure pulsed holographic interferometry makes it possible to obtain phase-shifted interferograms from a single interferogram of the tested object and retrieve the phase information for OPD (optical path difference) map creation. Two-reference beam double-pulsed Ruby laser holographic interferometer has been adapted to transient and continuous phenomena studies. It is non-destructive, real-time, and definitive approach in identification of vibrational modes, displacements, and motion geometries. Results of a vibration study performed by double-pulsed Ruby laser holographic interferometry for wave excited by shaker with continuous sinusoidal excitation and propagated over the car door panel surface are presented in this paper."
Active vibration control of automotive like panels,"Automotive panels can be great transmitter of undesired sound from external sources. The ability of controlling the noise and vibration performance of such panels is critical to the perceived quality of a vehicle. Passive vibration systems are currently used in vehicles, but they tend to be heavy in nature and capable of covering only a frequency range above 100-200 Hz. Active vibration control is a potential alternative to passive control. Its cost and adaptability of an active system has been the primary concern for implementation in the automotive sector. Recent developments in the control implementation and lower cost of electronics in general have made the gap between active and passive much smaller than before. An active vibration control has been developed and demonstrated into an automotive-like panel. Such panel was sized to represent a door of a military vehicle. Several excitation sources were considered and included engine excitation, road excitation and blast excitation due to the military design constraints. The active vibration control system is comprised of strain sensors, piezoelectric actuators, a control system and a power amplifier to drive the control actuators. Several control strategies were used depending on the source of excitation. Once of the primary features of all the control strategies used was their adaptability to the change in conditions. A 10 to 15 dB vibration reduction was obtained over the frequency range of interest. As the physically conditions changed (shift in frequency), the control algorithm adapted to the new conditions and vibration reduction could be obtained achieving the same level of performance as during the initial target. The cost of the solution was maintained to a minimum, and its potential production costs for automotive quantities was estimated to be in the order of few tens of dollars (US)."
Analysis of Determining Parameters of Acoustical Comfort Inside Vehicles,"The description of subjectively perceived acoustical comfort inside vehicle compartments is a complex challenge. On the one hand, it depends on physically measurable events like acoustical stimuli with a defined sound pressure level and frequency distribution. On the other hand, it is also strongly dependent on further factors like the customer's individual expectations, the previously made experiences and other contextual influences. Furthermore, many different driving conditions have to be considered for a customer-related assessment of driving comfort. In this paper, the mechanisms of acoustical comfort inside vehicle compartments are described on basis of various measurements, listening tests and qualitative assessments. The acoustical properties of driving noises at various driving conditions were taken into account as well as room-acoustical parameters of vehicle interiors and factors of speech communication between passengers. An interview-based qualitative assessment did confirm the importance of speech communication aspects for the comfort experience and well-being of both driver and passengers. These aspects are for example the speech intelligibility, the quality of conversational speech and further the increase in the vocal effort during a conversation in the presence of driving noises. In addition, the characteristics of driving noises at stationary and non-stationary driving conditions were under examination, both in a listening studio and on a test track. The results of the listening tests and customer surveys are connected to acoustical and psychoacoustical parameters to identify the customer-preferred properties of driving noises. This identification is further itemized to an empirically determined optimal ratio between the main noise components (powertrain-induced, chassis-induced and wind-induced noises). As a result of all these investigations, a prediction model of acoustical comfort will be developed in the future."
Research on the Application of Aluminum Door Beam for Automobiles,"Door beams are attached inside car doors as one way to protect passengers from shock when the car is side impacted. Though door beams made of high tensile strength steel predominate now, the use of aluminum is growing rapidly to reduce weight. The effects of cross-section and types alloy on the performance of aluminum extrusions as door beams were investigated. As the result, aluminum door beams were developed which have bending proper2ties comparing favorably with those of door beams made of high tensile strength steel with a tensile strength of 1470 N/mm2. Since the shape of the cross-section of aluminum extrusions is versatile, non-symmetric cross-sections composed of regions with different wall thicknesses and lengths can be produced. On the basis of this technology, a technology to design door beams with required bending properties for any car model was developed. This technology is already been utilized in various automobiles. In this paper, the characteristics of these newly developed aluminum door beams will be introduced along with the results of practical use of them [1]."
A Magnetorheological Door Check,"Several shortcomings of mechanical door checks are overcome using a magnetorheological damper. Because the damper is electrically actuated, it can check in any desired position. The logical decision to activate or release the door check can be made either by passive circuitry based on input signals from switches attached to door handles or under microprocessor control, in which case the decision can take into account a variety of unconventional input factors, including the magnitude of the force applied to the door, the rate of change of the applied force, and the angle of door opening. With the addition of an appropriate proximity sensor, the controllable damper can prevent the door from inadvertently hitting a nearby obstacle. Details of the damper mechanism are described, and several implemented control strategies, both passive and microprocessor based, are discussed."
Enhanced Security Flight Deck Doors-Commercial Airplanes,"In the wake of the 9/11/2001 hijacking events, the Federal Aviation Administration (FAA) has emphasized the need for enhanced flight deck doors on commercial airplanes. The paper describes enhanced flight deck door, which meets the new FAA requirements for intrusion resistance and ballistic protection. In addition, the new door meets the existing requirements for rapid decompression, flight crew security and rescue."
Design of Experiments (DOE) and Other 6-Sigma Tools Used to Minimize Rear Door Opening Vibration on a Vehicle,"Very often, engineering problems involve several variables that have different physical behavior making theoretical modeling complex and difficult. In the present paper, 6-Sigma tools were used to develop an experimental model that describes the system. The issue in focus was the vibration observed at the top of rear door during normal opening operation, causing the impression of a fragile structure. The resulting experimental model was able to explain door opening vibration with only 15% of error. In addition, it was possible to choose the best combination and setting for each variable in order to achieve a product benchmarking value."
Passive Close-Off Feature for Sample Acquisition and Retention,"The current coring bit and percussive drilling style works very well for strong rocks; however, when coring into weak, crumbling rock, the core tends to break apart and simply fall out of the bit. These rocks, powder, and other debris can have useful information that is lost when they fall out of the bit after the core has been made, as there is no retention feature in place. A retention mechanism for coring into weak rocks was developed."
SPSCGR,"SPSCGR generates a contact graph suitable for use by the ION (Interplanetary Overlay Network) DTN (Delay/Disruption Tolerant Network) implementation from data provided by the JPL SPS (Service Preparation System) Portal. Prior to SPSCGR, there was no way for a mission or other entity to route DTN traffic across the DSN without manually constructing a contact graph. SPSCGR automates this process of contact graph construction."
Reactionless Drive Tube Sampling Device and Deployment Method,"A sampling device and a deployment method were developed that allow collection of a predefined sample volume from up to a predefined depth, precise sampling site selection, and low impact on the deploying spacecraft. This device is accelerated toward the sampled body, penetrates the surface, closes a door mechanism to retain the sample, and ejects a sampling tube with the sample inside. At the same time the drive tube is accelerated, a sacrificial reaction mass can be accelerated in the opposite direction and released in space to minimize the momentum impact on the spacecraft. The energy required to accelerate both objects is sourced locally, and can be a spring, cold gas, electric, or pyrotechnic. After the sample tube is ejected or extracted from the drive tube, it can be presented for analysis or placed in a sample return capsule."
Wallops Flight Facility 6U Advanced CubeSat Ejector (ACE),"Six-unit (6U) CubeSats are recognized as the next nanosatellite to be considered for standardization. The CubeSat standard established by California Polytechnic University (Cal Poly), which applies to 1U–3U sizes, has proven to be a valuable asset to the community. It has both provided design guidelines to CubeSat developers and a consistent, low-risk interface to launch service providers. This has ultimately led to more flight opportunities for CubeSats. A similar path is desired for the 6U CubeSat. Through this process of standardization, a consistent, low-risk interface for the 6U needs to be established."
The Future of Aircraft Electrification,"A resounding applause fills an auditorium in Fort Worth, Texas, as engineers, researchers, and business leaders stand in unison to celebrate the closing keynote of another aerospace conference. Participants grab their belongings and file out into the street where they clamor for rides to the airport. I hail a cab and glance at my watch, noting that in 45 minutes, I'm expected at a meeting in Austin-about 200 miles away. Just then, a taxi pulls up to the curb. I step inside, and as soon the door closes, I'm up in the air. Fifteen minutes later, I land in Austin beside my car; I hop in and head to the meeting location. I arrive soon after, with time to spare. Stories like this were used in the past to paint a futuristic picture of the transportation industry. Visionaries would share them to entice businesses to invest in new modes of travel that, at the time, seemed only possible in dreams."
SAE Electronics + Connectivity 2012-11-28,"Integration opens the door Semiconductor suppliers are integrating many functions into power devices while also cutting power consumption in an environment, automotive doors, where 8-bit microcontrollers still hold sway."
Safety with Convenience: Applying Low Cost Obstacle Detection Technology to Powered Closure Systems with Express Motion,"There is a growing market for Powered Closure Systems and a strong trend to incorporate express motion for convenience. This drives the need to incorporate obstacle detection using anti-pinch technology for safety reasons according to vehicle safety standards applicable in the governing region. Powered Closure systems include windows, sunroofs, rear hatches, trunk lids and sliding doors with other applications under consideration. This paper will investigate the application of the technology in a cost-effective manner to these systems. A brief comparison of technologies will be considered and the paper will review motor-based control to explore the range of conditions required for obstacle detection. The challenge to provide good protection for obstacle intrusion without causing inadvertent system reversals due to environmental conditions will be presented. A primary focus of the paper will discuss the development of a technology “toolbox” to allow adaptation for the various applications and system to system variation. There is some hesitancy in the market to introduce this available technology due to lack of understanding or concern over cost. This paper seeks to show that the uses of low cost technology can be applied to provide improved safety while increasing convenience to the vehicle operator."
Innovative Thermoplastic Cavity Filler Design Solutions,"The use of acoustic cavity fillers or “baffles” to prevent the propagation of air borne and structure borne noise, water and dust into the interior spaces of vehicle structures has been in practice for many years. Continuous development of new OEM requirements has pushed the state of the art concerning the design and functionality of these cavity sealing systems. Various technologies are available to OEMs to provide sealing that will prevent water and dust penetration, maximize performance of vehicle HVAC systems, and minimize the propagation of noise from the body structure into the interior compartment under operating conditions. Generally, three types of cavity sealing systems are available: pre-formed thermoplastic-based systems that incorporate a heat reactive thermoplastic sealer applied to a nylon or steel “carrier” for attachment to the body structure; heat reactive rubber-based sealer systems that incorporate a carrier, push pin or pressure sensitive adhesive layer for attachment; and bulk applied chemically reactive two component polyurethane or expandable “foam” systems. In this case study, a challenge undertaken by this supplier was to provide a thermoplastic baffle design of equal or lesser weight compared to a competitive, die-cut rubber-based technology currently in production at a particular OEM, while achieving equivalent acoustical performance. This paper will document the alternative design proposals and development activities that were pursued to meet this particular objective."
Optimization through NVH Analysis to Improve the Vehicle Acoustics and Quality of Transmission Shifter,"Gear shift quality and feel determines the performance of the transmission. It is dependent on the synchronizer, shift system, gear shifter etc in a transmission. In this study the impact of the transmission shifter on the gear shift feel is detailed. More focus is paid towards the feel in terms of NVH characteristics. The rear wheel drive transmission shifter can be bifurcated into direct and indirect shift type. Indirect shifter are of two types, the rod type shifter and the cable shifter. The rod type shifter is analyzed in detail. All the shifters are connected to the gear shift top lever which is the customer interface for gear shifting. The design of the top lever is critical in getting the optimal feel of shifting and the mounting of the shifter is critical to improve its NVH characteristics. Different design iteration of the top lever are studied to illustrate the impact of the weight and stiffness on the vibration. CORRELATION OF A SEMI REMOTE SHIFTER MOUNTING ON VEHICLE ACOUSTICS AND VIBRATION is also established. The shifter dynamics are simulated and its NVH characteristics were studied for 4 cylinder engine and 3 cylinder engine. The shifter strength is analyzed with CAE on hyper mesh. The mechanical links involved and the iterations done to improve the shift quality as well the vibration levels of the hand ball are described. The biasing and shifting force and the travel of the knob in each gear are optimized by verifying through GSQA. Various rear wheel drive transmission have been used as an example to illustrate the shifter dynamics and efficiency. In a three cylinder engine the optimization of the semi remote shifter for the vibration and noise is critical. The solution can be common with a 4-cylinder engine if the arrangement is similar. The extent of benefit would be less on the 4-cylinder than with the 3-cylinder engine as it is more balanced. This study deals primarily with the mounting scheme of the semi remote shifter and its impact on the vehicle NVH. As the 3-cylinder engine configuration has the maximum drive train vibration, it enables a better understanding of the impact of the semi remote shifter mounting scheme on the vehicle. The analysis would help in the selection of the optimum semi remote shifter configuration and material with design adaptation suited to the engine configuration providing better NVH result on the vehicle."
Vibro-Impact Analysis of Manual Transmission Gear Rattle and Its Sound Quality Evaluation,"Experimental schemes, frequency characteristics, subjective and objective sound quality evaluation and sound quality prediction model establishment of a certain mass-production SUV (Sport Utility Vehicle, SUV) manual transmission gear rattle phenomenon were analyzed in this paper. Firstly, vehicle experiments, including experiment conditions, vibration acceleration sensor and microphone arrangements and especial considerations in experiments, were described in detail. Secondly, through time-frequency analysis, broadband characteristics of manual transmission gear rattle noise were identified and vibro-impact of gear rattle occurs in the frequency range of 450~4000Hz on the vehicle idle condition and the creeping condition. Thirdly, based on bandwidth filtering processing of gear rattle noise, subjective assessment experiments by a paired comparison method were carried out. Evaluation results passed triangular loop verification and Spearman correlation coefficient examination, and then subjective annoyance results of each noise sample were calculated. Further, objective evaluation results, based on two physical acoustics parameters and six psychological acoustics parameters, were obtained respectively. Finally, comprehensive evaluation of subjective and objective results was analyzed by the MLR (Multiple Linear Regression, MLR) method. It’s concluded that AI (Articulation Index) was the appropriate parameter that’s closely related to subjective annoyance results, and correlation coefficient of AI and subjective annoyance results was up to 0.948. Sound quality prediction model of gear rattle was then established on the vehicle idle condition and the creeping condition. Overall in this paper, research achievements could be adopted to solve practical engineering problems (especially gear rattle problem), and furthermore it could reduce R&D (Research and Design, R&D) cycle, labor costs and material costs dramatically."
Systems Engineering Approach for Voice Recognition in the Car,"In this paper, a systems engineering approach is explored to evaluate the effect of design parameters that contribute to the performance of the embedded Automatic Speech Recognition (ASR) engine in a vehicle. This includes vehicle designs that influence the presence of environmental and HVAC noise, microphone placement strategy, seat position, and cabin material and geometry. Interactions can be analyzed between these factors and dominant influencers identified. Relationships can then be established between ASR engine performance and attribute performance metrics that quantify the link between the two. This helps aid proper target setting and hardware selection to meet the customer satisfaction goals for both teams."
A Tailgate(Trunk) Control System Based on Acoustic Patterns,"When customers use a tailgate (or trunk), some systems such as power tailgate and smart tailgate have been introduced and implemented for improving convenience. However, they still have some problems in some use cases. Some people have to search for the outside button to open the tailgate, or they should take out the key and push a button. In some cases, they should move their leg or wait a few seconds which makes some people feel that it is a long time. In addition, they have to push the small button which is located on the inner trim in order to close the tailgate. This paper proposes a new tailgate control technology and systems based on acoustic patterns in order to solve some inconvenience. An acoustic user interaction (AUI) is a technology which responds to human’s rubbing and tapping on a specific part analyzing the acoustic patterns. The AUI has been recently spotlighted in the automotive industry as well as home appliances, mobile devices, musical instruments, etc. The AUI is a technology that can extend to rich-touch beyond multi-touch. The AUI can be easily applied and adapted even to the systems which need a large touch recognition area or have complex shape and surface. This paper addresses how to recognize the users’ intention and how to control the tailgate using acoustic sensors and patterns. If someone who has the smart key wants to open the tailgate, he or she only needs to knock on the outer panel of the tailgate twice. When they want to close the tailgate, just touching anywhere of the inner trim of the tailgate will do. Various digital filters and algorithms are used for acoustic signal processing, and the effectiveness of the proposed methods is shown by a real tailgate system with a micro control unit. Finally, we suggest other applications of vehicles which use AUI technology."
A CFD Analysis Method for Prediction of Vehicle Exterior Wind Noise,"High frequency wind noise caused by turbulent flow around the front pillars of a vehicle is an important factor for customer perception of ride comfort. In order to reduce undesirable interior wind noise during vehicle development process, a calculation and visualization method for exterior wind noise with an acceptable computational cost and adequate accuracy is required. In this paper an index for prediction of the strength of exterior wind noise, referred to as Exterior Noise Power (ENP), is developed based on an assumption that the acoustic power of exterior wind noise can be approximated by the far field acoustic power radiated from vehicle surface. Using the well-known Curle’s equation, ENP can be represented as a surface integral of an acoustic intensity distribution, referred to as Exterior Noise Power Distribution (ENPD). ENPD is estimated from turbulent surface pressure fluctuation and mean convective velocity in the vicinity of the vehicle surface. Therefore calculations and visualizations of ENP and ENPD can be implemented in an unsteady Computation Fluid Dynamics (CFD) simulation without extra cost for acoustical computation. Applications of ENP and ENPD in vehicle development process can provide not only quantitative information about the acoustic power of exterior wind noise in parts of vehicle but also an indication of the location of dominant sources of exterior wind noise as well as the associated turbulent flows. The information of ENP and ENPD are helpful in order to set targets for exterior wind noise around each part of vehicle and to establish countermeasure designs for reduction of exterior wind noise."
Reanalysis of Linear Dynamic Systems using Modified Combined Approximations with Frequency Shifts,"Weight reduction is very important in automotive design because of stringent demand on fuel economy. Structural optimization of dynamic systems using finite element (FE) analysis plays an important role in reducing weight while simultaneously delivering a product that meets all functional requirements for durability, crash and NVH. With advancing computer technology, the demand for solving large FE models has grown. Optimization is however costly due to repeated full-order analyses. Reanalysis methods can be used in structural vibrations to reduce the analysis cost from repeated eigenvalue analyses for both deterministic and probabilistic problems. Several reanalysis techniques have been introduced over the years including Parametric Reduced Order Modeling (PROM), Combined Approximations (CA) and the Epsilon algorithm, among others. It has been shown that the Modified Combined Approximations (MCA) method - an improvement over CA - is the most efficient reanalysis technique for problems with a large number of degrees of freedom. This paper proposes an improvement of the MCA method using frequency shifts. Numerical examples are presented and results are compared with existing methods."
Comparative Study of Adaptive Algorithms for Vehicle Powertrain Noise Control,"Active noise control systems have been gaining popularity in the last couple of decades, due to the deficiencies in passive noise abatement techniques. In the future, a novel combination of passive and active noise control techniques may be applied more widely, to better control the interior sound quality of vehicles. In order to maximize the effectiveness of this combined approach, smarter algorithms will be needed for active noise control systems. These algorithms will have to be computationally efficient, with high stability and convergence rates. This will be necessary in order to accurately predict and control the interior noise response of a vehicle. In this study, a critical review of the filtered-x least mean square (FXLMS) algorithm and several other newly proposed algorithms for the active control of vehicle powertrain noise, is performed. The analysis examines the salient features of each algorithm, and compares their system performance. Numerical simulations utilizing synthesized data, are conducted to study the convergence rates of these algorithms. These convergence rates are critical for the noise control outcome. Furthermore, measured powertrain noise response is employed, to verify the system’s performance under more realistic conditions. The individual engine orders are targeted for attenuation or enhancement, to achieve the desired vehicle interior sound quality."
Frontloading Approach for Sound Package Design for Noise Reduction and Weight Optimization Using Statistical Energy Analysis,"First time right vehicle performance and time to market, remains all automotive OEMs top priority, to remain competitive. NVH performance of product communicates impression to customer, remains one of the most important and complex attribute to meet, considering performances to be met for 20 Hz -6000 Hz. Frontloading techniques (FEM/BEM/SEA/MBD) for NVH are critical and necessary to achieve first time right NVH performance. Objective of this paper is to present a frontloading approach for automotive sound package optimization (absorber, barrier and damper elements) for SUV vehicle. Current process of designing sound package is mainly based on experience, competitive benchmarking of predecessor products. This process (current process) heavily depend on testing and validation at physical prototype and happens at later stages of program, especially on tooled up body. This is because, structure borne noise development, sealing and leakage path treatment refinement assume priority over sound package development. This way of working has impacted on validation timelines, late changes in peripheral system, leading to cost increase and time delays. High frequency simulations (using statistical energy analysis) provides opportunity in terms of being able to evaluate design options and frontload sound package design in parallel with structure borne NVH development. In this exercise, SEA (statistical energy analysis) was used to predict full vehicle cabin noise (400 Hz-6000 Hz) by modelling all major paths (structure borne and air borne) present in vehicle. All major sources of excitation such as powertrain vibrations, suspension vibrations and engine bay noise, tyre patch noise, exhaust noise were used to predict cabin noise. Static and dynamic load cases were used to validate modelling confidence and model updating. Contribution analysis was used to identify dominant sources, transfer paths for optimization of sound package for performance and weight."
Uncertainty Analysis of High-Frequency Noise in Battery Electric Vehicle Based on Interval Model,"The high-frequency noise issue is one of the most significant noise, vibration, and harshness problems, particularly in battery electric vehicles (BEVs). The sound package treatment is one of the most important approaches toward solving this problem. Owing to the limitations imposed by manufacturing error, assembly error, and the operating conditions, there is often a big difference between the actual values and the design values of the sound package components. Therefore, the sound package parameters include greater uncertainties. In this article, an uncertainty analysis method for BEV interior noise was developed based on an interval model to investigate the effect of sound package uncertainty on the interior noise of a BEV. An interval perturbation method was formulated to compute the uncertainty of the BEV’s interior noise. The sound absorption coefficient and transmission loss of the sound package were obtained through tests, and a statistical energy analysis model of the BEV was established. The acoustic loads of the BEV were tested and the interior noise of the cabin was analyzed under certain working conditions. Uncertain parameters were introduced to describe the sound package system of the firewall. The sensitivities of the uncertain parameters were analyzed using the numerical sensitivity analysis method. The effect of interior noise was predicted through the interval perturbation method, and the robustness of the system was analyzed under the influence of uncertain parameters."
Road Noise Evaluation by Sound Quality Simulation Module,"An objective evaluation of sound quality is a technical bridge connecting sound pressure level (SPL) and human auditory sensation. In this paper, an algorithm is proposed for calculating objective evaluation parameters of sound quality (including loudness, sharpness and articulation index), considering acoustic characteristics of human external ear, middle ear and inner ear to reflect auditory sensation. A sound quality simulation (SQS) module is coded according to the algorithm. The module is used for evaluating sound quality of road noise from an SUV in three steps. Firstly, interior noise is predicted by integrating finite-element method (FEM), hybrid FE-SEA method, and statistical energy analysis (SEA) for low frequency (20~315 Hz), medium frequency (315~500 Hz), and high frequency (>500 Hz) in 1/3 octave band, respectively. The predicted interior noise SPLs are compared with the measured results, with deviations less than 3dB in average. Secondly, the sound quality parameters are calculated using the predicted SPLs in the SQS module. The predicted and measured loudness, sharpness, and articulation index are compared, with average deviations less than 5%. Finally, the predicted interior noise is filtered by the SQS module in 1/3 octave band, to determine the dominant contribution bands for the sound quality parameters. Several optimized designs are implemented to optimize the sound quality parameters, and validated by experiments."
Windshield Glare from Bus Interiors: Potential Impact on City Transit Drivers at Night,"Windshield glare at night is a safety concern for all drivers. Public transit bus drivers also face another concern about glare caused by interior lighting sources originally designed for passenger safety. The extent to which interior light reflections contribute to glare is unknown. Unique methods for measuring discomfort and disability glare during bus driving were developed. An initial simulation study measured windshield luminance inside of a New Flyer D40LF diesel bus parked in a controlled, artificial, totally darkened test environment. Findings indicated significant disability glare (from elevated luminance) in the drivers’ primary field of view due to interior reflections. Any reduction in contrast would result in less prominent glare if actual driving conditions differ. To assess this, levels of windshield glare were also measured with the bus parked on the roadside under the “background glow” of the urban environment. Findings reveal that under road conditions the extent of disability glare from interior reflections is much less, but not negligible, when contrast is reduced. The information gathered in these studies may be useful to manufacturers and transit authorities to improve conditions for drivers and the travelling public. Measurement methods developed in this study may prove useful for assessing elements of interior design. The difference between disability and discomfort glare is discussed. The results provide directions for implementation of glare control strategies."
Lockheed Martin Low-Speed Wind Tunnel Acoustic Upgrade,"The Lockheed Martin Low-Speed Wind Tunnel (LSWT) is a closed-return wind tunnel with two solid-wall test sections. This facility originally entered into service in 1967 for aerodynamic research of aircraft in low-speed and vertical/short take-off and landing (V/STOL) flight. Since this time, the client base has evolved to include a significant level of automotive aerodynamic testing, and the needs of the automotive clientele have progressed to include acoustic testing capability. The LSWT was therefore acoustically upgraded in 2016 to reduce background noise levels and to minimize acoustic reflections within the low-speed test section (LSTS). The acoustic upgrade involved detailed analysis, design, specification, and installation of acoustically treated wall surfaces and turning vanes in the circuit as well as low self-noise acoustic wall and ceiling treatment in the solid-wall LSTS. The preservation of the aerodynamic flow quality and the reduction in background noise levels in the LSTS were demonstrated by a series of measurements that were performed both prior to and after the acoustic upgrade."
Advancement in Vehicle Development Using the Auto Transfer Path Analysis,"This paper presents the most recent advancement in the vehicle development process using the one-step or auto Transfer Path Analysis (TPA) in conjunction with the superelement, component mode synthesis, and automated multi-level substructuring techniques. The goal is to identify the possible ways of energy transfer from the various sources of excitation through numerous interfaces to given target locations. The full vehicle model, consists of superelements, has been validated with the detailed system model for all loadcases. The forces/loads can be from rotating components, powertrain, transfer case, chain drives, pumps, prop-shaft, differential, tire-wheel unbalance, road input, etc., and the receiver can be at driver/passenger ears, steering column/wheel, seats, etc. The traditional TPA involves two solver runs, and can be fairly complex to setup in order to ensure that the results from the two runs are consistent with subcases properly labeled as input to the TPA utility. However, auto TPA allows necessary data needed for the TPA analysis to be requested in a single frequency response analysis run. The TPA breaks down the total response to partial contributions from interface points under operation loads. Partial contributions to total response are then computed by multiplying transfer function with the force transmitted through each interface location. By comparing the results of two-step TPA with auto TPA, the effectiveness and efficiency of the auto TPA have been demonstrated for three load cases: a) powertrain excitation for cruising acceleration to engine torque (A/T) and noise to engine torque (P/T), b) propshaft imbalance, and c) rough road excitation, which is based on the power spectral density (PSD) function."
Development of Feedback-Based Active Road Noise Control Technology for Noise in Multiple Narrow-Frequency Bands and Integration with Booming Noise Active Noise Control System,"When a vehicle is in motion, noise is generated in the cabin that is composed of noise in multiple narrow-frequency bands and caused by input from the road surface. This type of noise is termed low-frequency-band road noise, and its reduction is sought in order to increase occupant comfort. The research discussed in this paper used feedback control technology as the basis for the development of an active noise control technology able to simultaneously reduce noise in multiple narrow-frequency bands. Methods of connecting multiple single-frequency adaptive notch filters, a type of adaptive filter, were investigated. Based on the results, a method of connecting multiple filters that would mitigate mutual interference caused by different controller transmission characteristics was proposed. This method made it possible to implement controllers with amplitude and phase characteristics in multiple narrow-frequency bands corresponding to design values, and to achieve the target noise-reduction. Additionally, in feedback-based road noise control, the amplitude of the control output signal changes drastically depending on the frequency characteristics of the road surface. When this technology was integrated with the already-commercialized booming noise control system, a method to adjust the range of each controller output automatically was applied, achieving integration while balancing noise reduction performance under normal conditions with control stability when the vehicle passes over a large-input surface."
Source-Path-Contribution Methodologies across a Wide Range of Product Types,"Source-path-contribution (SPC) analysis, or transfer-path-analysis, is a test based method to characterize noise and vibration contributions of a complex system. The methodology allows for the user to gain insight into the structural forces and acoustic source strengths that are exciting a system, along with the effects of the structural and acoustic paths between each source and a receiver position. This information can be utilized to understand which sources and/or paths are dominating the noise and vibration performance of a system, allowing for focused target cascading and streamlined troubleshooting efforts. The SPC process is widely used for automotive applications, but is also applicable for a wide range of product types. For each unique application the basic SPC principles remain constant, however best practices can vary for both measurement and analysis depending on the type of system being evaluated. In this paper the application of the SPC process is described across a range of different applications including automotive, agricultural, small engine, and smaller component-level applications."
Current Status and Future Developments of ANC Systems,"Active Noise Control (ANC) has long been seen as emerging technology. During recent years, however, it became popular in new vehicle and infotainment platforms within a broad range of OEMs. This paper summarizes the current status and lessons learned of production systems (as well as those entering production soon) and gives an outlook on how ANC and related technologies will integrate in future vehicles and audio/infotainment architectures."
Coupling CFD with Vibroacoustic FE Models for Vehicle Interior Low-Frequency Wind Noise Prediction,"With the reduction of engine and road noise, wind has become an important source of interior noise when cruising at highway speed. The challenges of weight reduction, performance improvement and reduced development time call for stronger support of the development process by numerical methods. Computational Fluid Dynamics (CFD) and finite element (FE) vibroacoustic computations have reached a level of maturity that makes it possible and meaningful to combine these methods for wind noise prediction. This paper presents a method used for coupling time domain CFD computations with a finite element vibroacoustic model of a vehicle for the prediction of low-frequency wind noise below 500 Hz. The procedure is based on time segmentation of the excitation load and transformation into the frequency domain for the vibroacoustic computations. It requires simple signal processing and preserves the random character as well as the spatial correlation of the excitation signal. The aeroacoustic load is applied on the entire outer surface of the vehicle body. The computed results are validated against wind tunnel measurements on a production vehicle. The numerical and experimental investigations provide some insight into the mechanisms involved in underbody wind noise."
Sideglass Turbulence and Wind Noise Sources Measured with a High Resolution Surface Pressure Array,"The authors report on the design and application of a high resolution micro-electro-mechanical (MEMS) microphone array for automotive wind noise engineering. The array integrates both sensors and random access memory (RAM) chips on a flexible circuit board that eliminates high channel count wiring and allows the array to be deployed on automobile surfaces in a convenient “stick-on/peel-off” configuration. These arrays have potential application to the quantitative evaluation of interior wind noise from measurements on a clay model in the wind tunnel, when used in conjunction with a body vibro-acoustic model. The array also provides a high resolution turbulence measurement tool, suitable for validation of computation fluid dynamics (CFD) simulations for wind noise. The authors' report on the wavenumber-frequency structure of flow turbulence measured in different flow regions on a side glass and the corresponding contributions to interior wind noise."
Prediction of Interior Noise in a Sedan Due to Exterior Flow,Aero-vibro-acoustic prediction of interior noise associated with exterior flow requires accurate predictions of both fluctuating surface pressures across the exterior of a vehicle and efficient models of the vibro-acoustic transmission of these surface pressures to the interior of a vehicle. The simulation strategy used in this paper combines both CFD and vibro-acoustic methods. An accurate excitation field (which accounts for both hydrodynamic and acoustic pressure fluctuations) is calculated with a hybrid CAA approach based on an incompressible unsteady flow field with an additional acoustic wave equation. To obtain the interior noise level at the driver's ears a vibro-acoustic model is used to calculate the response of the structure and interior cavities. The aero-vibro-acoustic simulation strategy is demonstrated for a Mercedes-Benz S-class and the predictions are compared to experimental wind tunnel measurements.
Optimization of a Porous Ducted Air Induction System Using Taguchi's Parameter Design Method,"Taguchi method is a technology to prevent quality problems at early stages of product development and product design. Parameter design method is an important part in Taguchi method which selects the best control factor level combination for the optimization of the robustness of product function against noise factors. The air induction system (AIS) provides clean air to the engine for combustion. The noise radiated from the inlet of the AIS can be of significant importance in reducing vehicle interior noise and tuning the interior sound quality. The porous duct has been introduced into the AIS to reduce the snorkel noise. It helps with both the system layout and isolation by reducing transmitted vibration. A CAE simulation procedure has been developed and validated to predict the snorkel noise of the porous ducted AIS. In this paper, Taguchi's parameter design method was utilized to optimize a porous duct design in an AIS to achieve the best snorkel noise performance. The virtual experiments based on an orthogonal array in the parameter design method were conducted by the developed simulation procedure and the optimized design was recommended. Furthermore, the parts based on the optimized design are manufactured and tested to verify if the intended performance and other high priority requirements for the AIS are met. It was concluded that a traditional CAE analysis enhanced with robustness technique is an efficient tool to optimize the AIS design in this case study."
The Predictive Simulation of Exhaust Pipe Narrow-band Noise,"A method of predictive simulation of flow-induced noise using computational fluid dynamics has been developed. The goal for the developed method was application in the vehicle development process, and the target of the research was therefore set as balancing the realization of a practical level of predictive accuracy and a practical computation time. In order to simulate flow-induced noise, it is necessary to compute detailed eddy flows and changes in the density of the air. In the research discussed in this paper, the occurrence or non-occurrence of flow-induced noise was predicted by conducting unsteady compressible flow calculation using large eddy simulation, a type of turbulence model. The target flow-induced noise for prediction was narrow-band noise, a type of noise in which sound increases in specific frequency ranges. Assuming the area of generation of flow-induced noise to be the exhaust pipe, including the complex shape of the muffler, predictive accuracy was verified under conditions that modeled measurements in steady-state flow test equipment. In order to reduce computation time while maintaining predictive accuracy, calculation methods were combined and computation times compared. This made it possible to reduce computation time by 61% against that in the initial stage of development of the method. In addition, a study utilizing multiple exhaust pipe shapes indicated that a correlation existed between the number of computation cells and computation time. The developed method has made it possible to predict the occurrence of narrow-band noise within a practical computation time."
Automobile Wind Noise Speed Scaling Characteristics,"Wind noise, an aeroacoustic phenomenon, is an important attribute that influences customer sensation of interior quietness in a moving vehicle. As a vehicle travels faster, occupants' sensation of wind noise becomes increasingly objectionable. The purpose of this work is to investigate the increase of wind noise level perceived by a driver in response to an increase in wind speed. Specifically, it explores how much the level of wind noise at the DOE (driver outboard ear) would vary in response to a change in wind speed based on the test data obtained in a wind tunnel from ten vehicles that belong to several different passenger vehicle segments. The first part of this work studies the change of the SPL (sound pressure level) in response to a change in wind speed U. It shows that the SPL(dBA) approximately scales to U5.7 at the DOE and to U6.3 in the far-field, which could be interpreted as the dominance of dipoles. The second part of this work looks into the scaling of loudness measured in Zwicker sones that represent the human auditory sensation of wind noise level. It shows that the human perception of the wind noise loudness scales to U1.7 approximately, which indicates that the wind noise loudness sensation is doubled when the vehicle speed incurs a 50% increase."
Assessing the Aeroacoustic Response of a Vehicle to Transient Flow Conditions from the Perspective of a Vehicle Occupant,"On-road, a vehicle experiences unsteady flow conditions due to turbulence in the natural wind, moving through the unsteady wakes of other road vehicles and travelling through the stationary wakes generated by roadside obstacles. Separated flow structures in the sideglass region of a vehicle are particularly sensitive to unsteadiness in the onset flow. These regions are also areas where strong aeroacoustic effects can exist, in a region close to the passengers of a vehicle. The resulting aeroacoustic response to unsteadiness can lead to fluctuations and modulation at frequencies that a passenger is particularly sensitive towards. Results presented by this paper combine on-road measurement campaigns using instrumented vehicles in a range of different wind environments and aeroacoustic wind tunnel tests. A new cabin noise simulation technique was developed to predict the time-varying wind noise in a vehicle using the cabin noise measured in the steady environment of the wind tunnel, and a record of the unsteady onset conditions on the road, considering each third-octave band individually. The simulated cabin noise predicted using this quasi-steady technique was compared against direct on-road cabin noise measurements recorded under the same flow conditions to assess the response of the vehicle to oncoming flow unsteadiness. The technique predicted the modulation of the wind noise under unsteady on-road conditions with good fidelity. This is because the cabin noise response to oncoming flow unsteadiness remained generally quasi-steady up to fluctuation frequencies of approximately 2 to 5 Hz, with fluctuations at higher scales having a progressively smaller impact, and because most of the onset flow fluctuation energy on the road occurs at frequencies below this threshold. The relative impact of the baseline level of cabin noise and the sensitivity of the cabin noise to changes in yaw angle were assessed in terms of occupant perception and this highlighted the importance of modulation. This can provide guidance when assessing the on-road wind noise performance of vehicle geometry modifications and of different vehicles."
Planetary Airlock and Suitlock Requirements and Alternate Approaches,"This study describes the operational requirements for planetary surface access and compares the performance of a hatch, airlock, suitlock, and suitport. The requirements for mitigating dust, performing EVA (ExtraVehicular Activity) by only part of the crew, and use on Mars as well as the Moon are strong reasons to prefer an airlock over a simple hatch, which would require depressurizing the habitat and sending all the crew on EVA. A requirement for minimum cost would favor the hatch above all. A suitlock provides better dust mitigation than an airlock, but at higher cost and complexity. A suitlock accommodating two crew meets requirements for buddy assistance and ability to help an incapacitated crewmember. Two suitlocks would provide redundant airlocks. A suitport, similar to a suitlock but having a suit-bulkhead pressure seal and no outer airlock door, provides dust mitigation and operational flexibility similar to the suitlock at lower cost, but increases risk and limits contingency response. A combined airlock/suitlock/suitport has the broadest capability and flexibility."
The Study of Roller Hemming Process for Aluminum Alloy via Finite Element Analysis and Experimental Investigations,"Recently the automotive industry faces many competitive challenges including weight and cost reduction to meet the needs for high fuel efficiency. Therefore, the use of light metals such as aluminum alloys has been increased to produce the body structure of light-weight vehicles. However, since the formability of aluminum alloy is not as good as that of steel, it needs a special attention to body manufacturer during their forming process. Roller hemming technology has been introduced as a new production technique which has several advantages in terms of cost and time saving for trial and error. Since hemming is the last forming process in stamping, it determines the external quality of automotive outer parts such as doors, hood and trunk-lid. In this study, the implicit finite element analysis of roller hemming process on the flat surface-straight edge panel was performed by using the commercial code ANSYS. This study shows the process of roller hemming simulation with Von Mises stress and effective strain results. In addition, experimental investigations have been done to compare the results between the simulation and experiment."
A Modern Development Process to Bring Silence Into Interior Components,"Comfort and well-being have always been connected with a flawless interior acoustic, free of any background noise or BSR, (buzz, squeak and rattle). BSR noises dominate the interior acoustic and represent one of the main sources for discomfort often causing considerable warranty costs. Traditionally BSR issues have been identified and rectified through extensive hardware testing, which by its nature intensifies toward the end of the car development process. In the following paper the integration of a virtual BSR validation technique in a modern development process by the use of appropriate CAE methods is presented. The goal is to shift, in compliance with the front loading concept, the development activities into the early phase. The approach is illustrated through the example of an instrument panel, from the early concept draft for single components to an assessment of the complete assembly. In a second and innovative example a combination of a virtual door slam analysis with a subsequent BSR analysis is examined. Every analysis result shown in the paper will be compared with corresponding test results."
Obstacle Detection for Power Folding Seats,"In the past years the automotive industry has equipped it's vehicles with more and more automated power driven functions. Starting with the “express up/down ” functions for power windows and “easy entry/exit” functions of memory seats, automated power movements have also been introduced into power sliding doors as well as power liftgates. In contrast to “press & hold” switch activated movement, where the operator takes responsibility for the movement, the control unit of the “automated” or “one-touch” movement has to provide some sort of obstacle detection or pinch protection. This paper deals with the adaptation of a pinch protection algorithm for linear movements like power windows or memory seat applications to the rotational movement of power folding seats. With the considerable weight of a seat that is involved the motor torque changes along the travel of the seat, sometimes even reaching negative values in those positions where obstacles would most likely need to be detected. On the other hand, obstacle detection must be less sensitive in areas where the seat needs to be moved against gravity and where complex seat mechanics introduce non-linear torque requirements. The paper addresses these issues and describes basic functionality, such as how to obtain a voltage compensated torque equivalent signal from a hall sensor speed signal. It also describes the challenges that arise from rotational movement."
Using Spherical Beamforming to Evaluate Wind Noise Paths,"Microphone array based techniques have a growing range of applications in the vehicle development process. This paper evaluates the use of Spherical Beamforming (SB) to investigate the transmission of wind-generated noise into the passenger cabin, as one of the alternative ways to perform in-vehicle troubleshooting and design optimization. On track measurements at dominant wind noise conditions are taken with the spherical microphone array positioned at the front passenger head location. Experimental diligence and careful processing necessary to enable concise conclusions are briefly described. The application of Spherical Harmonics Angularly Resolved Pressure (SHARP) and the Filter-And-Sum (FAS) algorithms is compared. Data analysis variables, run-to-run repeatability and system capability to identify design modifications are studied. It is demonstrated that the Spherical Beamforming is a powerful tool to visualize dominant noise paths in vehicle, providing valuable information for the wind noise control at the transmission paths rather than using the standard single microphone operational data at the observer location."
Study of Coupling Behavior of Acoustic Cavity Modes to Improve Booming Noise in Passenger Vehicles,Interior sound quality is one of the significant factors contributing to the comfort level of the occupants of a passenger car. One of the major reasons for the deterioration of interior sound quality is the booming noise. Booming noise is a low frequency (20Hz∼300Hz) structure borne noise which occurs mainly due to the powertrain excitations or road excitations. Several methods have been developed over time to identify and troubleshoot the causes of booming noise [1]. In this paper an attempt has been made to understand the booming noise by analyzing structural (panels) and acoustic (cavity) modes. Both the structural modes and the acoustic modes of the vehicle cabin were measured experimentally on a B-segment hatchback vehicle using a novel approach and the coupled modes were identified. Panels contributing to booming noise were identified and countermeasures were taken to modify these panels to achieve decoupling of structural and cavity modes which results in the reduction of cabin noise levels. This is followed by countermeasure validation resulting into booming noise reduction.
Multidisciplinary Design Optimization of BEV Body Structure,"Blade Electric Vehicle (BEV) with a light body plays an important role in saving the energy and reducing the exhaust emission. However, reducing the body weight need to meet the heterogeneous attributes such as structural, safety and NVH (Noise, Vibration and Harshness) performance. With the rapid development of finite element (FE) analysis technology, simulation analysis is widely used for researching the complex engineering design problem. Multidisciplinary Design Optimization (MDO) of a BEV body is a challenging but meaningful task in the automotive lightweight. In present research, the MDO is introduced to optimize a BEV Body-in-White (BIW). The goal of optimization is to minimize the mass of the BIW while meeting the following requirements: structural performance (the bending and torsion stiffness is increased), NVH performance (the first overall torsion frequency is increased), and safety performance (the roof crush resistance is improved).The sample points were obtained by using Design of Experiment (DOE) with optimal Latin hypercube. The approximation models of mass, bending stiffness, torsion stiffness, modal and safety were established with the polynomial response surface method (RSM). The thicknesses of nine parts of the BIW were selected to be optimized by Muti-island Genetic Algorithm (MGA) method. After the MDO of the BIW, the paper drew the following conclusions: 1.The predictive values of the approximation and the results of FE simulation had a good agreement with an error less than 5.00% and the former met the engineering requirements; 2.The weight of the BIW was reduced by 2.00% and the optimized BIW met all prescribed requirements about structural, NVH and safety performance."
Approach to Control the in Cab Noise without Affecting Passenger Comfort in AC Midi Buses,"This paper discusses various fruitful iterations / experiments performed to reduce air flow induced noise without compromising on total air flow requirement for thermal comfort and ways to avoid heat ingress inside the bus. Also the paper discusses the devised process for noise reduction through front loading of computer aided engineering and computational fluid dynamics analysis. Air conditioning buses in light commercial vehicle (LCV) segment is growing market in India, especially for applications like staff pick-up and drop, school applications and private fleet owners. The air-conditioning system is typically mounted on bus roof top and located laterally and longitudinally at center. It is an easiest and most feasible way to package air conditioning system to cater the large passenger space (32 to 40 seats) with the conditioned air. This makes air conditioning duct design simple and commercially viable. Most of the LCV buses are with front engine configuration which adds more heat and noise to driver and passenger compartment, this demands for isolation of driver's area from passenger area by means of partition in between. In case of buses without partition engine noise is more dominant, but in case of buses with partition, blower noise of roof mounted AC system is more perceivable in passenger area. The larger glass area, limitation on glass tint percentage and mandate for not to use curtain added more challenges in front of thermal engineer to device effective cabin cooling system to cater huge heat load and achieve required human comfort."
Development of Prediction Method for Dynamic Strain on Windshield during Passenger Airbag Deployment,"The objective of this study is to accurately predict the dynamic strain on the windshield caused by the deployment of the airbag in a short term without vehicle tests. The following assumption is made as to the dynamic pressure distribution on the windshield: The deployment of the airbag is fast enough to ignore spatial difference in the patterns of the pressure time histories. Given this assumption, significant parameters of the dynamic pressure distribution are as follows: 1) the distribution of the maximum pressure during contact between the airbag and the windshield, and 2) the characteristic of the force time histories applied to the windshield by the deploying airbag. In this study, the prediction method consists of a simplified airbag deployment test and an FE simulation. The simple deployment test was conducted to measure the peak pressure distribution between the airbag and a flat panel simulating the windshield. The pressure time history curves were determined by scaling the force time histories from the load cells. The scale factor was identified for each of the measuring points on the pressure measurement film. Prescribed pressure time histories were directly applied to the part of the FE mesh specifically used to load the windshield. In order to validate the developed prediction method, the strain from the FE simulation was compared with that from strain gauges in the vehicle tests. The results showed that the predicted strain on the windshield caused by the airbag deployment correlated well with the data measured in the vehicle tests, suggesting that the prediction method developed in this study can be a valuable tool for improving the efficiency of development."
Prediction of Structureborne Noise in a Fully Trimmed Vehicle Using Poroelastic Finite Elements Method (PEM),"Since the last decade, the automotive industry has expressed the need to better understand how the different trim parts interact together in a complete car up to 400 Hz for structureborne excitations. Classical FE methods in which the acoustic trim is represented as non-structural masses (NSM) and high damping or surface absorbers on the acoustic cavity can only be used at lower frequencies and do not provide insights into the interactions of the acoustic trims with the structure and the acoustic volume. It was demonstrated in several papers that modelling the acoustic components using the poroelastic finite element method (PEM) can yield accurate vibro-acoustic response such as transmission loss of a car component [1,2,3]. The increase of performance of today's computers and the further optimization of commercial simulation codes allow computations on full vehicle level [4,5,6] with adequate accuracy and computation times, which is essential for a car OEM. This paper presents a study of a fully trimmed vehicle excited by structureborne excitations with almost all acoustic trims such as seats, dash insulator, instrument panel, headliner… which are modelled as poroelastic finite element (PEM) parts. Simulation results are compared with extensive measurement results. The interactions between structure, acoustic trims and acoustic volume are illustrated and finally the analysis of several design changes such as trim material properties or geometry modifications is demonstrated."
A Computational Aeroacoustic Study of Windshield Wiper Influence on Passenger Vehicle Greenhouse Windnoise,"This paper presents an approach to numerically simulate greenhouse windnoise. The term “greenhouse windnoise” here describes the sound transferred to the interior through the glass panels of a series vehicle. Different panels, e.g. the windshield or sideglass, are contributing to the overall noise level. Attached parts as mirrors or wipers are affecting the flow around the vehicle and thus the pressure fluctuations which are acting as loads onto the panels. Especially the wiper influence and the effect of different wiper positions onto the windshield contribution is examined and set in context with the overall noise levels and other contributors. In addition, the effect of different flow yaw angles on the windnoise level in general and the wiper contributions in particular are demonstrated. As computational aeroacoustics requires accurate, highly resolved simulation of transient and compressible flow, a Lattice-Boltzmann approach is used. The noise transmission through the interior is then modeled by statistical energy analysis (SEA), representing the vehicle cabin and the panels excited by the flow. Results are verified by comparisons to windtunnel experiments."
Attenuation of Aeroacoustic Noise of a Typical Van Using Passive Devices through CFD Simulation,"The present numerical analysis aims at studying the effect of changes in profile of van on aero-acoustic noise and aerodynamic drag. The numerical analysis is carried out using commercial CFD software, ANSYS Fluent, with k-epsilon & Large Eddy Simulation turbulence models. In present study five models of truck are analysed, including baseline model at different Reynolds numbers, namely 0.391, 0.415 and 0.457 million. In order to reduce the aero-acoustic noise, various profile modifications have been adapted on existing van model by adding a top and bottom diffuser at the rear of the truck. The comparison has been done with respect to coefficient of drag, coefficient of pressure, pressure contours for all four cases. It is observed from the simulation results among different modifications of truck, adding a top and bottom diffuser of 15 degrees at the rear end of truck gives the maximum reduction in aero-acoustic noise up to 9.4% and aerodynamic drag reduction of 3.8 % as compared to baseline model, at a speed of 81 km/h."
Performance Analysis on 3D Printed Beak-Shaped Automotive Tail Fin Filled with Honeycomb Cellular Structure,"The concept of “bionic design” has driven the developments of automotive design. In this paper, a novel beak-shaped automotive tail fin with honeycomb cellular structure is proposed based on the idea of “bionic design”. Beak-shaped appearance is utilized to meet the requirement of aerodynamics performance, inner honeycomb cellular structure is filled to achieve more lightweight space. This paper starts from the establishment of three dimensional (3D) model based on the real characteristics of sparrow’s beak. On this basis, aerodynamic performances of novel beak-shaped tail fin and conventional shark tail fin are analyzed by experiment. Finally, the stiffness and modal analyses of solid beak-shaped tail fin and honeycomb beak-shaped tail fin are carried out respectively. The results indicate that the deformation of solid beak-shaped tail fin and honeycomb beak-shaped tail fin satisfy the basic requirements. In addition, the first order modal frequencies of solid and honeycomb beak-shaped tail fins are both far away from body vibration frequency and effectively avoid resonance. Compared with solid beak-shaped tail fin, the weight of honeycomb beak-shaped tail fin decreases by about 25%. Thus, the novel honeycomb beak-shaped tail fin proposed in this work demonstrates outstanding performance in terms of aerodynamic performances, structural stiffness enhancement and weight reduction."
Automatic Speech Recognition System Considerations for the Autonomous Vehicle,"As automakers begin to design the autonomous vehicle (AV) for the first time, they must reconsider customer interaction with the Automatic Speech Recognition (ASR) system carried over from the traditional vehicle. Within an AV, the voice-to-ASR system needs to be capable of serving a customer located in any seat of the car. These shifts in focus require changes to the microphone selection and placement to serve the entire vehicle. Further complicating the scenario are new sources of noise that are specific to the AV that enable autonomous operation. Hardware mounted on the roof that are used to support cameras and LIDAR sensors, and mechanisms meant to keep that hardware clean and functioning, add even further noise contamination that can pollute the voice interaction. In this paper, we discuss the ramifications of picking up the intended customer’s voice when they are no longer bound to the traditional front left “driver’s” seat. Considerations are made to the possibilities of new microphone construction and layouts to provide coverage for all potential passengers, and cost-efficient minimal microphone packages are discussed. Additionally, if the automaker chooses to initiate the ASR interaction with a “wake up word”, instead of installing Push to Talk (PTT) buttons for every seat, we discuss how the multiple microphone’s placements can be leveraged to identify the seat issuing the command, and focus further ASR interactions with that location in the car."
A Non-Contact Technique for Vibration Measurement of Automotive Structures,"The automotive and aerospace industries are increasingly using the light-weight material to improve the vehicle performance. However, using light-weight material can increase the airborne and structure-borne noise. A special attention needs to be paid in designing the structures and measuring their dynamics. Conventionally, the structure is excited using an impulse hammer or a mechanical shaker and the response is measured using uniaxial or multi-axial accelerometers to obtain the dynamics of the structure. However, using contact-based transducers can mass load the structure and provide data at a few discrete points. Hence, obtaining the true dynamics of the structure conventionally can be challenging. In the past few years, stereo-photogrammetry and three-dimensional digital image correlation have received special attention in collecting operating data for structural analysis. These non-contact optical techniques provide a wealth of distributed data over the entire structure. However, the stereo camera system is limited by its field of view of the cameras and can only measure the response on the parts of the structure that cameras have the line of sight. Therefore, a single pair of Digital Image Correlation (DIC) cameras may not be able to provide deformation data for the entire structure. In current work, a multi-view 3D DIC approach is used to predict the vibrational characteristics of a full vehicle. A pair of DIC cameras is roved over the entire vehicle to capture the deformation data of each field of view. The measured data includes the geometry and displacement data which is mapped into the global coordinate system using 3D transformation matrices. The obtained data in the time domain for each field of view is transformed to the frequency domain using the Fast Fourier Transformation (FFT) to extract the operational deflection shapes and resonant frequencies for each field of view. The obtained deflection shapes are scaled and stitched in the frequency domain to extract the operating deflection shapes of full vehicle."
Extensive Correlation Study of Acoustic Trim Packages in Trimmed Body Modeling of an Automotive Vehicle,"In the automotive sector, the structure borne noise generated by the engine and road-tire interactions is a major source of noise inside the passenger cavity. In order to increase the global acoustic comfort, predictive simulation models must be available in the design phase. The acoustic trims have a major impact on the noise level inside the car cavity. Although several publications for this kind of simulations can be found, an extensive correlation study with measurement is needed, in order to validate the modeling approaches. In this article, a detailed correlation study for a complete car is performed. The acoustic trim package of the measured car includes all acoustic trims, such as carpet, headliner, seats and firewall covers. The simulation methodology relies on the influence of the acoustic trim package on the car structure and acoustic cavities. The challenge lies in the definition of an efficient and accurate framework for acoustic trimmed bodies. Two different approaches to achieve this objective are reviewed. In the first approach, the acoustic trim package is modeled as a set of porous and solid layers represented by finite elements in physical coordinate system. The acoustic trim models update the modal fluid / structure model of the car body and car cavity. The second approach uses impedance surfaces to apply the acoustic absorption of the trim on the car cavity side. It uses a Virtual Kundt’s tube. Both approaches are solved as state of the art modal analysis. The result of the correlation study with measurements provides acceleration and Sound Pressure Level (SPL) results for different configurations and excitations, introducing the Root Mean Squared Deviation (RMSD). The expected difference between the two approaches is obtained. The first approach results in higher correlation accuracy than the second approach, while the second approach has advantages in computational time."
Towards a Quiet Vehicle Cabin Through Digitalization of HVAC Systems and Subsystems Aeroacoustics Testing and Design,"With the rise of electric autonomous vehicles, it has become clear that the cabin of tomorrow will drastically evolve to both improve ride experience and reduce energy consumption. In addition, autonomy will change the transportation paradigm, leading to a reinvention of the cabin seating layout which will offer the opportunity to climate systems team to design quiet and even more energy efficient systems. Consequently, Heat and Ventilation Air Conditioning (HVAC) systems designers have to deliver products which perform acoustically better than before, but often with less development time. To success under such constraints, designers need access to methods providing both assessment of the system (or subsystems) acoustic performance, and identification of where the designs need to be improved to reduce noise levels. Such methods are often needed before a physical prototype is requested, and thus can only be achieved in a timely manner through digital testing. Previous studies have demonstrated the ability of a CFD/CAA approach based on the Lattice Boltzmann Method (LBM) to predict HVAC system noise including real and complex ducts, registers, mixing unit and blower geometries. This LBM low dissipative numerical approach has indeed been shown to accurately capture turbulent and convective mechanisms and to propagate acoustic waves in ducted systems and in free-field. Combined with a noise source identification strategy, these methods provide the ability to visualize the noise sources inside the system, as well as to identify and rank noise-generating design features - a unique design methodology not available with physical testing. In this paper, such an approach is presented based on two HVAC systems layout, targeting two different vehicles. To answer the need for systems and subsystems predictions, simulation results are correlated to experiment for configurations with blower alone, blower + air intake, and for full HVAC system (blower + air intake + mixing unit). Finally, an in-depth analysis of the flow noise sources contributions to a microphone location is performed, and countermeasures are discussed."
New ‘Bottlebrush’ Electroactive Polymers Make Dielectric Elastomers Increasingly Viable for Use in Devices,"A multi-institutional research team has developed a new electroactive polymer material that can change shape and size when exposed to a relatively small electric field. The advance overcomes two longstanding challenges regarding the use of electroactive polymers to develop new devices, opening the door to a suite of applications ranging from microrobotics to designer haptic, optic, microfluidic, and wearable technologies. The work was performed by researchers at North Carolina State University, the University of North Carolina at Chapel Hill, Carnegie Mellon University, and the University of Akron."
2021 Ford Bronco aims to kick some Jeep,"“There is nothing on this truck that is superfluous - no decorative chrome or extraneous styling. It's designed for function, not fashion,” explained Paul Wraith, chief designer for Ford's much-anticipated 2021 Bronco. “Super-short overhangs for aggressive approach, departure and breakover angles. Slim ‘hips’ for off-road agility. Everything is exactly where you need it. Getting that stuff right is harder than you think,” he admitted. To create the much-anticipated U725 (as the new 2- and 4-door Bronco is known internally and by suppliers), Wraith and his team decided to veer outside of Ford's traditional product-development process. It was the only way to execute the program's broad scope and unique requirements. “As we developed the truck, we invented a new human-centered methodology,” Wraith told media ahead of Bronco's July 13 unveiling. “We made low-fidelity models out of foam-core packing materials which drove our [prototype] shops crazy,” he said. “And we ended up skipping a whole bunch of typical studio processes. This stirred things up quite a bit.”"
Getting driverless trucks onto roadways,"Autonomous developers at TuSimple address many technical issues, but they also must consider regulations and operating modes. The developers who are creating autonomous systems have plenty of complex technical questions that must be analyzed and solved, but their challenges don't stop there. Design teams also have to plan for the use cases of driverless vehicles, even going so far as to plan for what might happen if the vehicle has to sacrifice itself to avoid a serious accident. The challenges associated with the sea change wrought by autonomous trucking has opened the door for startups like TuSimple, a Chinese startup that's partially funded by Nvidia. The company is developing digital control systems, focusing on both the prototypes needed to prove the safety of driverless trucks as well as the many issues associated with getting them into day-to-day operations."
Trucking Without Truckers,"The challenges are myriad, but automated-trucking developer TUSimple believes the efficiencies of true depot-to-depot driverless hauling are too promising to ignore. The developers who are creating autonomous systems have plenty of complex technical questions that must be analyzed and solved, but their challenges don't stop there. Design teams also have to plan for the use cases of driverless vehicles, even going so far as to plan for what might happen if the vehicle has to sacrifice itself to avoid a serious accident. The challenges associated with the sea change wrought by autonomous trucking has opened the door for companies such as TuSimple, a Chinese startup that's partially funded by Nvidia. The company is developing digital control systems, focusing on both the prototypes needed to prove the safety of driverless trucks as well as the many issues associated with getting them into day-to-day operations."
Steel stands TALL,"Mobility's longtime incumbent material maintains its star status for vehicle structures through constant innovation-and a collaborative development model. In 2014, just before Ford shook the industry with the introduction of its aluminum-intensive F-150, Ducker Worldwide released a study for the aluminum industry. The report predicted that the light metal would dominate the North American light-truck segment in the next new-model development cycle. Some seven out of ten pickups in the next round were going to be AL-intensive, the study opined. A tidal wave appeared to be building. Five years later, not a single pickup has entered production with an AL-intensive cab and bed. While Ford changed over the body structures of its all-new 2018 large SUVs to aluminum, steel rules the midsized 2019 Ranger. In the enemy camps, the 2019 Chevrolet and GMC Silverado and Sierra 1500 and their brawnier HD cousins continue GM's mixed-materials strategy for pickups and SUVs. FCA's Ram and Jeep brands have stuck mainly with steel structures; the new JL-series Jeep Wrangler changed to aluminum doors (and hinges), hood, fenders and windshield frame, utilizing Alcoa's new C6A1 high-form alloy and its 6022 and A951 alloys."
Thermal Technology System Acquires Heat Data to Count People,"The Flowslide, developed by Royal Boon Edam Group Holding BV, is a combination of a revolving door and curved sliding panels, installed at Charles de Gaulle Airport, Paris. The Flowslide offers a complete physical separation between two crossing passenger flows on a single floor, allowing arriving and departing passengers to use a single door. The entry and exit points open and close alternatively within the curved wall of the revolving door, while keeping the passengers separate. As the two sets of passengers never come into contact with each other — despite using the same doorway — the Flowslide has enabled today's higher levels of security to be met, without the need to redevelop the terminal."
Fabrication of Lightweight Armored Doors for HMMWVs,"A document describes a concept for fabricating lightweight armored doors for the Army’s high-mobility multipurpose wheeled vehicles (HMMWVs). Essentially, the concept is to reinforce high-hard (HH) steel armored doors used on some HMMWVs with a laminated, woven, high-tensile-strength glassfiber/ polyester-matrix composite that has performed well as armor material in previous military applications. A fabrication procedure for implementing the concept, described in the document, can be summarized as follows:"
RoboSimian Software System from the DARPA Robotics Challenge Finals,"A software architecture to allow semi-autonomous mobile manipulation of highly dexterous robots under degraded communications was developed to enable remote operation of a mobile manipulation robot as a first responder in a disaster-response scenario. The software architecture is structured to be adaptable at the lowest level and repeatable at the highest level. This architecture strikes the right balance between autonomy and supervision, and lets the robot excel in its capabilities (repeatability, strength, precision) and lets the operators excel at their capabilities (situational awareness, context, high-level reasoning)."
Airborne Hyperspectral Imaging System,"A document discusses a hyperspectral imaging instrument package designed to be carried aboard a helicopter. It was developed to map the depths of Greenland’s supraglacial lakes. The instrument is capable of telescoping to twice its original length, allowing it to be retracted with the door closed during takeoff and landing, and manually extended in mid-flight. While extended, the instrument platform provides the attached hyperspectral imager a nadircentered and unobstructed view of the ground."
Driving the CAR toward 54.5 mpg,"Chances are good that if you're involved with automotive manufacturing strategy, you know Jay Baron. As President and CEO of the Center for Automotive Research (CAR) in Ann Arbor, Dr. Baron and his research teams are engaged with technology issues across a broad front, but even a brief conversation with him reveals his deep passion for plants, advanced processes and materials. Get him talking about lightweighting and he won't stop. The following exchange was taken from our July 2016 interview. At what point does the rising cost of vehicle compliance allow the over-the-horizon lightweighting technologies to enter production?"
"Racing toward autonomous future, Cadillac and Mercedes-Benz reveal sultry, drive-it-yourself concept cars","In the autonomous-vehicle future, will the ultimate luxury become driving for yourself? That appears to be the suggestion from General Motors' Cadillac premium-car unit and Germany's Mercedes-Benz-both unveiled lusciously-proportioned concept cars at August's Monterey Car Week, where executives for both companies took pains to say the vehicles would be best enjoyed if, well, you actually drove them."
Concurrent Development Environment Combining Mechanical and Control Systems for PBD and PSD,"Due to advancements in multi-body dynamic analysis methodologies, virtual prototyping has been extended into various fields. Those methods can be applied to confirm behavior of the mechanical systems, to determine the necessary driving forces, and to predict the loads for each component of the system. Further, those methods combined with the control system have been applied to the controller tuning. Virtual evaluation environments have been developed, including the multi-body dynamic analysis, and have been applied to a power back door system (PBD) and a power sliding door system (PSD). As a result, development costs and timing have been reduced due to the utilization of these new evaluation methods."
Simulation of Hot Stamping Process With Advanced Material Modeling,"Advanced material modeling was conducted to describe the thermal-mechanical behavior of Boron Steel during hot stamping, a process in which blanks at 900 °C are formed and quenched between cold dies. Plastic deformation, thermal dilatation and phase transformation were incorporated in the constitutive model and a user-defined subroutine was developed to interface with LS-DYNA. Simulation was conducted on the hot stamping process of a door intrusion beam to gain insight into the physics of the process. Results showed significant influence of the thermal cycle on final product. It was also demonstrated that the program developed can be used as an early feasibility tool to determine baseline processing parameters and to detect potential defects in products without physical prototyping."
Honeywell's Automotive Door Latch Design is Ideal for Corporate Latch Strategy,"In response to consumer demand, automakers are adding more safety, security, and convenience features to vehicle access control systems. Also, in a continuing effort to be more profitable, automakers are reducing costs by outsourcing the design of systems/sub-systems/components, reducing their supply base, and minimizing part numbers by sharing components across several platforms. In an attempt to improve efficiency and productivity, many OEM's have adopted a “corporate latch” strategy, implementing the same latch across several manufacturing platforms and marketing divisions. Honeywell's revolutionary door latch design efficiently and cost effectively addresses vehicle OEMs' current and future requirements for performance and functionality. Utilizing this modular latch design allows OEMs to maximize design re-use, minimize tooling and development costs, hasten time to market, reduce program risk by utilizing pre-proven/validated designs and allows for upgrades in functionality through transparent design modifications that appear seamless within the application. Honeywell's Universal Latch provides all levels of functionality within the same packaging envelope and is the perfect enabler for a “corporate latch” strategy. Features and functions offered by the latch include: Central Locking Super Locking Selective Locking Electric Child Safety Power Door Releasing (Unlatching) Power Door Closing (Cinching) Most impressive is the fact that Honeywell's latch provides all of these features and functions with one small motor! Currently, competitive latch designs require the utilization of as many as three distinct motors to offer the same capabilities. This paper will present characterization data for the Universal Latch and compare its performance to competitive latches currently on vehicles. Furthermore, a feature value analysis will be provided to illustrate the benefits and savings the Honeywell design can provide to the entire access control system. After considering all of the facts presented in the paper, the reader will easily conclude that Honeywell's automotive door latch is smaller, lighter, quieter, faster, safer, and more cost effective than any automotive door latching/locking system on the market today."
Validation of Non-linear Load-Controlled CAE Analyses of Oil-Canning Tests of Hood and Door Assemblies,"Two finite element methodologies for simulating oil-canning tests on closure assemblies are presented. Reflecting the experimental conditions, the simulation methodologies assume load-controlled situations. One methodology uses an implicit finite-element code, namely ABAQUS®, and the other uses an explicit code, LS-DYNA®. It is shown that load-displacement behavior predicted by both the implicit and explicit codes agree well with experimental observations of oil-canning in a hood assembly. The small residual dent depth predictions are in line with experimental observations. The method using the implicit code, however, yields lower residual dent depth than that using the explicit code. Because the absolute values of the residual dent depths are small in the cases examined, more work is needed, using examples involving larger residual dent depth, to clearly distinguish between the two procedures. The analysis performed using the implicit code was significant more efficient (in terms of CPU hours) than the analysis done using the explicit code. The effects of forming strains are qualitatively examined. Forming induced thickness changes and plastic strains may not have a significant effect on oil-canning behavior, but may influence the residual dent depth strongly. Further reinforcement of the predictability of the methodology is demonstrated by an oil-canning simulation, using the implicit code, of a door assembly."
Reliability Analysis of Systems with Nonlinear Limit States; Application to Automotive Door Closing Effort,"In this paper, an efficient method for the reliability analysis of systems with nonlinear limit states is described. It combines optimization-based and simulation-based approaches and is particularly applicable for problems with highly nonlinear and implicit limit state functions, which are difficult to solve by conventional reliability methods. The proposed method consists of two major parts. In the first part, an optimization-based method is used to search for the most probable point (MPP) on the limit state. This is achieved by using adaptive response surface approximations. In the second part, a multi-modal adaptive importance sampling method is proposed using the MPP information from the first part as the starting point. The proposed method is applied to the reliability estimation of a vehicle body-door subsystem with respect to one of the important quality issues -- the door closing effort. The superiority of the proposed method, in terms of efficiency and accuracy, is demonstrated with a numerical example of highly nonlinear limit state problem, as well as an automotive door closing effort application. A generalized framework for reliability estimation is also proposed for problems with large numbers of random variables and complicated limit states."
An Acoustical Imaging Processing for the Localization of Acoustic Sources inside a Vehicle: Method and Results for Tests on Road,"The localization of acoustic sources inside a moving vehicle presents at least two main difficulties. The zone to be explored may be important (such as a door, a window, the toe board): the use of a sound intensity probe may take an expensive time for the context of a moving car. The other difficulty is the presence of a background noise, increasing with the car speed. These two difficulties may be overcome by the use of a robust acoustical imaging method, but the utilization of the system requires a few precautions for the implementation and for the interpretation of the acoustic images. The purpose of this paper is to present the chosen acoustical imaging processing, based on the beamforming method, and the procedure for the set-up and tests. This processing and the procedure are applied for experimental tests on the road and for different configurations: constant and decelerating speed. Acoustic images are presented for the case of sources on a passenger door. To improve the interpretation of the results, acoustic images are obtained for different tape configurations. This study shows a good robustness of the system and reliable results. In addition, the use of beamforming processing allows a reduced time for the set-up and for the measurements."
Update on the Pininfarina “Turbulence Generation System” and its effects on the Car Aerodynamics and Aeroacoustics,"The Turbulence Generation System designed and built in Pininfarina in the years 1999-2002, has been in operation since the beginning of 2003. The purpose of this device is to reproduce in the wind tunnel a flow condition more similar to that found by the cars on the road, in terms of velocity profile and turbulence intensity/length scale. The paper reports an updated description of its mechanical and aerodynamic characteristics. Then it reports examples of results measured on some cars, in the condition of turbulent flow, regarding: Aerodynamics - time averaged and time-dependent aero coefficients. Aeroacoustics - auto spectra and psycho acoustic parameters. Deformation/vibration of some car body parts (bonnet, doors). The differences between these results and those measured in standard low-turbulence conditions are presented. In addition a description of some techniques that are used for these time-dependent measurements is reported."
Robust Design of Glass Run-Channel Seal,"Glass run-channel seals are located between DIW (Door in White) and window glass. They are designed to allow window glass to move smoothly while other two major requirements are met; (1) Provide insulation to water leakage and noise, and (2) Stabilize the window glass during glass movement, door slamming and vehicle operation. For a robust glass guidance system, it is critical to minimize the variation of seal compression force. In addition, it is desired to maintain a low seal compression force, which meets the minimum requirement for insulating water leakage/noise and stabilizing the window glass, for enhancing the durability of glass guidance system. In this paper, a robust synthesis and design concepts on the glass run-channel seal is presented. The developed concept is demonstrated with test data."
Ballistic Armoring of Passenger Cars on the Assembly Line Adds Quality and Passengers Comfort by Using Advanced and Light Weight Composite Materials,"Light weight composite materials were developed to provide ballistic protection to automobiles against handgun bullets and to increase passengers comfort by the elimination of UV radiation and reduction of infra-red solar energy and interior noise, without compromising the driving performance of the car. Structural designs were incorporated to be able to armor the car on the assembly line with the added benefits of turn-over time, cost reduction and quality of the finished assembly. Weight reduction of armor materials have been achieved with CrystalGard® and YellowGard®. For windows and windshield, CrystalGard® 17mm provides better ballistic protection against NIJ Level IIIA with a 27% weight reduction than the standard 21mm glass solution by using a double layer of polycarbonate. SolarBlock® eliminates the UV radiation and reduces 95% of the infra-red solar energy for added passengers comfort. For the ceiling, doors, dashboard and trunk, YellowGard® provides more than 80% weight reduction when compared with steel and reduces interior noise. YellowGard® is a thermo-formable Kevlar® fabric coated with a thermoplastic resin developed for ease of installation during assembly, resistance to high temperature and humidity, and reduced delamination upon multiple bullet hits. Advantages of online assembly of ballistic protection include the reinforcement of the door latch and column areas for durability, the adjustment of the suspension system to the original driving performance changed due to the extra weight, and the installation of the Kevlar® panels to the frame and doors during the assembly of the car to avoid cutting and welding the frame structure."
Swing Gate Development and Correlation Studies,"This paper documents the Engineering design of the rear door system for Ford's South American New Vehicle. This Closure system represents a first for the Engineering Department of Ford branded products and it also offers many industry firsts for the customer. This paper is not a concise A-Z document on Closure design, but a detailed report listing the important factors to consider in a Swing Gate."
"A Low Cost, Lightweight Solution for Soft Seamless Airbag Systems","OEM and Tier One integrated suppliers are in constant search of cockpit system components that reduce the overall number of breaks across smooth surfaces. Traditionally, soft instrument panels with seamless airbag systems have required a separate airbag door and a tether or steel hinge mechanism to secure the door during a deployment. In addition, a scoring operation is necessary to ensure predictable, repeatable deployment characteristics. The purpose of this paper is to demonstrate the development and performance of a cost-effective soft instrument panel with a seamless airbag door that results in a reduced number of parts and a highly efficient manufacturing process. Because of the unique characteristics of this material, a cost-effective, lightweight solution to meet both styling requirements, as well as safety and performance criteria, can be attained."
A Robust Procedure for Convergent Nonparametric Multivariate Metamodel Design,"Fast-running metamodels (surrogates or response surfaces) that approximate multivariate input/output relationships of time-consuming CAE simulations facilitate effective design trade-offs and optimizations in the vehicle development process. While the cross-validated nonparametric metamodeling methods are capable of capturing the highly nonlinear input/output relationships, it is crucial to ensure the adequacy of the metamodel error estimates. Moreover, in order to circumvent the so-called curse-of-dimensionality in constructing any nonlinear multivariate metamodels from a realistic number of expensive simulations, it is necessary to reliably eliminate insignificant inputs and consequently reduce the metamodel prediction error by focusing on major contributors. This paper presents a robust data-adaptive nonparametric metamodeling procedure that combines a convergent variable screening process with a robust 2-level error assessment strategy to achieve better metamodel accuracy. A door seal gap example is presented to illustrate the effectiveness and efficiency of the procedure."
Most Efficient Practice of Nearfield Measurements Inside a Car for Improving Acoustic Comfort,"A continuously growing demand comes from the automotive industry for optimization of materials and sound insulating products implementation inside the car, so as to propose the best acoustic performance at reduced costs. The acoustical holography system dBVISION developed by 01dB Acoustics & Vibration provides part of the solution to such a demand. Its demonstrated capability of measuring the acoustic field inside a vehicle makes it an advanced tool for performing extensive studies of the acoustic transparency of car openings as well as wind tunnel measurements. The developed technique allows now for: 1- Detailed localization of noise sources or acoustic weakness points inside the vehicle, 2- Knowledge of the acoustic energy distribution on elementary surfaces (such as doors, windscreen, roof, sealing system, etc.), 3- Reconstruction of the energy radiated by elementary surfaces in order to predict the acoustic pressure at the driver's and passengers' ears, 4- Estimation of the acoustic incidence of local modifications on components of the tested car. Technical background, together with the main features of this acoustical imaging system, will be exposed and the presentation will illustrate with practical examples how this fits to the project engineer process considering new acoustically driven design methods for a complete understanding and control of all components and systems involved in the car performance."
New-Generation PC/ABS Blends Help Meet Performance & Styling Requirements for Instrument Panel & Other Interior Components,"New targets for auto-interior components seek to improve thermal aging, low-temperature impact strength, recyclability, emissions/odor, processing productivity, and costs in order to meet new requirements for a 10-year car and new standards for consumer comfort. The pace of these demands is creating opportunities for blending technologies in a range of applications, including instrument panels, glove-box doors, top covers, retainers, and trim. A new generation of high-performance polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) resins based on proprietary formulation technology has been specifically developed to meet these demands in IP and other interior applications. This paper will focus specifically on a high-impact grade for IPs (in both standard- and low-emission formulations). This new technology was benchmarked against several earlier generation products from the same family, a new high-flow version using the same technology, and several competitive offsets. The results show a new class of PC/ABS blends offering best-in-class thermal aging, hydrolytic stability, low-temperature impact strength, and - for select applications - excellent odor and emissions. This has been accomplished without sacrificing processing performance. In fact, the new grades offer a broader processing window and faster cycle times for increased productivity and lower part costs."
Vehicular Electrical System Under Value Engineering Optic,"This work shows the “Value Methodology” application looking for to identify new alternatives for vehicular electrical energy system (battery, starter, generator, coils etc.). These alternatives must be feasible to the nowadays automobiles system. The electrical system studied in this job points out to engine with its main assembled options, or accessories, as air-conditioning, hydraulic power system (HPS), electrical lifter window, a thief deterrents alarm, door lockers, etc. Heavy electrical traffic conditions, which demand more energy, representing a bigger electrical charge, are being considered in this analysis. The main focus of this job is to show the internal parts reduction, meaning a better final cost to suppliers and carmakers, and consequently a better vehicle performance. Improvements achieved through this study must be appreciated."
Anti Pinch Protection for Power Operated Features,"Due to the ever-increasing number of power operated features in today's motor vehicle – electric window openers with auto-up function, power doors and lift gates, to mention just a few – and, of course a desire for more and more luxury features, safety is becoming a more and more important topic. This discourse describes the technology and the application of tactile (pressure sensitive) anti pinch systems and a non-touch (presence sensing) system which works on the basis of ultrasound. These systems are designed to be used as an alternative or in addition to indirect, motor-controlled anti pinch systems."
The History of Laminated Steel,"This paper discusses the background and history of “laminated steel” (commonly called “noiseless steel” or MPM). It provides the early development, where it came from, and how it was introduced to North America as a new tool for engineering acoustical solutions. A progressive timeline shows laminated steel from its earliest inception in Europe to its current role in today’s global market. Case histories along with examples of successful applications detail its important contribution in advancing the technology for component damping. Many manufacturing sources as well as end users have been impacted over the decades since it was first introduced. Some of those companies will be noted. The background information for this paper is provided by many of the individuals who were involved in the very early stages of its introduction as well those who are currently working to utilize the technology of laminated steel."
An Acoustic Target Setting and Cascading Method for Vehicle Trim Part Design,"One of the major concerns in the vehicle trim part design is the acoustic targets, which are generally defined by absorption area or coefficients, and sound transmission loss (STL) or sound insertion loss (SIL). The breaking down of acoustic targets in vehicle design, which is generally referred to as cascading, is the process of determining the trim part acoustic targets so as to satisfy full vehicle acoustic performance. In many cases, these targets are determined by experience or by subjective evaluation. Simulation based transfer path analysis (TPA), which traces the energy flow from source, through a set of paths to a given receiver, provides a systematic solution of this problem. Guided by TPA, this paper proposes a component level target setting approach that is based on the statistical energy analysis (SEA), an efficient method for vehicle NVH analysis in mid and high frequencies. Using a validated SEA model of the vehicle under consideration, the contributions of common noise sources and paths, which are generally defined on parts of sheet-metal with trim parts attached, can be evaluated. This allows the prediction of interior noise level due to various possible sound packages. On the base of this, acoustic target setting of trim parts can be defined as the solution of a mathematical optimization problem. The targets such as SIL of trim parts at certain frequency range are taken as design variables, and the vehicle level performance like the sound pressure level (SPL) at driver’s ear is incorporated into constraint functions. This approach is versatile and is suitable for traditional ICE vehicles and modern EVs. It can be used on a vehicle prototype at the early stages for target cascading, or on an existing vehicle model for NVH improvement. Several cases and examples on this target setting method have been discussed in the paper."
Inverse Vibration Problem Used for the Characterization of the Damping Added by a Trim Foam on a Plate,"Many solutions exist to insure the NVH comfort of ground and air vehicles, like heavy mass (bitumen pads), viscoelastic treatments and absorbing foams. The trim foam appears as an alternative to heavy solutions. To know the potential of these foams, a study of their capacities to damp vibration is done. A system, composed of a suspended plate, with a foam on it, is characterized in different contact conditions at the foam-plate interface (glued or not) and with different foam type. An experimental test facility is developed to identify the global damping of the structure: a laser vibrometer measures the displacement field of the foam-plate structure, and then an inverse method is used to determine the structural parameters. By changing the contact at the interface, it is possible to identify the contribution of the friction forces to the global damping of the structure. Another type of damping is the viscoelastic damping due to the intrinsic characteristics of the trim foam. With the help of FEA, it is possible to understand the influence of the damping effect. The implemented inverse methods are the Force Analysis Technique (FAT) and the Corrected Force Analysis Technique (CFAT), originally used for effort identification on a system. They are based on the motion equation of the system and the displacement field. In this study, these methods allow to determine the structural parameters, such as the elastic storage modulus and the loss factor."
Study of the Glass Contribution to the Interior Acoustics of a Car and Related Countermeasures,"This paper shows that the combination of a glass and passive acoustic treatment manufacturers can bring different benefits and considerably improve the interior acoustics of a vehicle. Glazing contributes to the design of the vehicle in addition to its primary role, good visibility and safety. From an acoustic point of view, this brings a challenge for the interior comfort. Indeed, glazing has no absorption and classically has an acoustic insulation weakness around its coincident frequency. In most of the cases, these different aspects make glazing one of the main contributors to the sound pressure level in the passenger compartment, and the trend is not one of change. However, there are possible countermeasures. One of which is the use of laminated glazing with acoustic PVB. This solution allows reducing the loss of insulation performance at the coincidence frequency. The other is the usage of passive interior acoustic trims. When properly positioned and optimized, the latter can be very effective and can tackle the frequency range that poses a problem. Especially since some technologies allow, by their process, to choose between the improvements of insulation or absorption. The aim of this paper is to understand the impact of the glazing on the interior acoustic for tires excitations. For that study, a measurement campaign together with some simulations models (FE and SEA) have been carried over on a European C-segment vehicle. A ranking of the different contributions is proposed. Then, in a second part, the countermeasures to improve the interior sound pressure level by adding optimized glazing and sound packages are presented."
Using Statistical Energy Analysis to Optimize Sound Package for Realistic Load Cases,"The statistical energy analysis (SEA) is widely used to support the development of the sound package of cars. This paper will present the preparation of a model designed to investigate the sound package of the new Audi A3 and associated correlation against measurements. Special care was given during the creation of the model on the representation of the structure to enable the analysis of structure borne energy flow on top of the classical airborne analysis usually done with SEA. The sound package was also detailed in the model to allow further optimization and analysis of its performance. Two real life load cases will be presented to validate the model with measurements. First, the dominating powertrain and a second load case with dominating rolling noise. An analysis of the contribution of the different source components and a way to diagnose the weak paths of the vehicle will be presented. The focus of this investigation is the application of optimally adjusted treatment."
Extended Solution of a Trimmed Vehicle Finite Element Model in the Mid-Frequency Range,"The acoustic trim components play an essential role in Noise, Vibration and Harshness (NVH) behavior by reducing both the structure borne and airborne noise transmission while participating to the absorption inside the car and the damping of the structure. Over the past years, the interest for numerical solutions to predict the noise including trim effects in mid-frequency range has grown, leading to the development of dedicated CAE tools. Finite Element (FE) models are an established method to analyze NVH problems. FE analysis is a robust and versatile approach that can be used for a large number of applications, like noise prediction inside and outside the vehicle due to different sources or pass-by noise simulation. Typically, results feature high quality correlations. However, future challenges, such as electric motorized vehicles, with changes of the motor noise spectrum, will require an extension of the existing approaches. In this paper, the vibro-acoustic frequency response of an existing MSC Nastran FE model is extended using the Actran Statistical Energy Analysis (SEA) approach, Virtual SEA. In Virtual SEA, the necessary information required to build the SEA system is extracted from the FE models. The fluid-structure Coupling Loss Factors (CLF) are computed through the Statistical modal Energy distribution Analysis (SmEdA) method. This method is a suitable candidate to account for acoustic trim effects based on analytical approach. The case studied consists of a trimmed body car model transfer function calculation. The result of the case study is an extensive correlation study containing measured and simulated transfer functions in low and mid-frequency range. Simulation results are derived from two approaches, FE method and Virtual SEA method."
Linking Body-In-White and Trimmed Body Dynamic Characteristics in View of Body-In-White Mode Shape Target Setting,"Target setting at Body-In-White (BIW) level is typically done for natural frequencies of global modes. Target values are commonly set based on experience or from benchmark studies with competitor vehicles. A link between these targets at BIW level and the vibro-acoustic targets at Trimmed Body (TB) level is not yet well established. Therefore, it is not always guaranteed that the TB targets will be met when the targets at BIW level are reached. Also, the other way around, not reaching a frequency target for a certain BIW mode does not necessarily imply that TB targets will not be met. Hence, there is a clear need for getting more insights in the relation between BIW dynamic properties and TB vibration behavior. In this paper techniques will be presented that establish the link between BIW and TB dynamic behavior. In addition, a large DOE campaign has been carried out to further link these dynamic properties to specific areas in the body design. Key elements in this paper are the introduction of a novel modal reduction method to extract the essential information from a large set of TB modes and a subspace correlation technique to link the critical TB modes with the global BIW modes. The results obtained with this study demonstrate that it is not enough to consider only natural frequencies of the BIW modes as a target but that their shape must be taken into account as well."
Evaluation of Laminated Side Glazing and Curtain Airbags for Occupant Containment in Rollover,"By their nature as chaotic, high-energy events, rollovers pose a high risk of injury to unrestrained occupants, in particular through exposure to projected perimeter contact and ejection. While seat belts have long been accepted as a highly effective means of retaining and restraining occupants in rollover crashes, it has been suggested that technologies such as laminated safety glazing or rollover-activated side curtain airbags (RSCAs) could alternatively provide effective occupant containment. In this study, a full-scale dolly rollover crash test was performed to assess the occupant containment capability of laminated side glazing and RSCAs in a high-severity rollover event. This allowed for the analysis of unrestrained occupant kinematics during interaction with laminated side glazing and RSCAs and evaluation of failure modes and limitations of laminated glazing and RSCAs as they relate to partial and complete ejection of unrestrained occupants. The dolly rollover was performed with a 2010 Chevrolet Express at a nominal speed of 43 mph, with unbelted anthropomorphic test devices (ATDs) positioned in the driver, right front passenger, and designated third, fourth, and fifth row seating positions. Vehicle dynamics and occupant kinematics were analyzed through evaluation of vehicle instrumentation, on-board and off-board real-time and high-speed video, post-test survey of the debris field, and post-test inspection of the vehicle and ATDs. Neither laminated side glazing nor RSCAs prevented complete or partial ejection of the ATDs. Two of the ATDs were completely ejected during the dolly rollover and six other ATDs were partially ejected. Fracture and peripheral separation of laminated side glazing was observed in association with ground contact, vehicle deformation, and ATD loading. Ejection in seating positions adjacent to RSCAs was observed in association with ATD loading and out-of-position interaction with the airbags. The findings of the present study demonstrate that laminated side glazing and rollover-activated side curtain airbags are not substitutes for proper seat belt use."
Enhanced Windshield CAE NVH Model for Interior Cabin Noise,"This paper describes a reliable CAE methodology to model the linear vibratory behavior of windshields. The windshield is an important component in vehicle NVH performance. It plays an integral role in interior cabin noise. The windshield acts as a large panel typically oriented near vertical at the front of vehicle’s acoustic cavity, hence modeling it accurately is essential to have a reliable prediction of cabin interior noise. The challenge to model the windshield accurately rises from the structural composition of different types of windshields. For automotive applications, windshields come in several structural compositions today. In this paper, we will discuss two types of windshield glass used primarily by automotive manufacturers. First type is the typical laminated glass with polyvinyl butyral (PVB) layer and second type is the acoustic glass with PVB and vinyl layers. Acoustic glass improves acoustic characteristics of the glass in a frequency range of ~ 1200 Hz to ~4000 Hz. Low frequency interior cabin noise studied with Finite Element Analysis (FEA) is typically below 400 Hz. The acoustic glass doesn’t provide substantial benefits in this range and in many cases we see an adverse contribution at lower frequencies since the acoustic windshield tend to be softer. In this paper, frequency dependency of PVB layer and acoustic vinyl layers are investigated. Multiple modeling techniques for windshield are demonstrated and the results are compared to physical tests. Finally an enhanced windshield modeling technique for low frequency interior cabin noise is proposed."
Virtual Verification of Light Reflection for Cluster and Side Mirror in Real Time Scenario,"In the very automobile world trends are changing at a very fast pace, due to continuous expectation changes by user and new regulatory requirements demand from government authorities with a very stringent timeline. In the current scenario, manufacturer has to wait for mock up for concept selection and physical proto build to conclude open points of design verification. This complete process takes more than a year to enhance the design maturity for further builds. In VECV we have created Cluster design standard to meet different level of cluster illumination & reflection at virtual level. We are defining the cluster light illumination based on our rigorous study on cluster reflection impact on side glass, windscreen and mirror. Accordingly we have packaged our mirror to minimize the impact of cluster reflection on mirror visibility. With the help of virtual verification of cluster and Side mirror inter co-relation of packaging, we significantly reduced the time loss and save huge cost required for developing proto build. Different options of mirror and cluster can be verified in quick session. With the help of virtual verification of mirror and cluster we are able to meet different regulatory compliances for light illumination without building a single proto build."
Road Noise Prediction Assessment Using CAE Instead of Costly and Time Consuming Physical Tests,"Virtual Product Development (VPD) with a vision to eliminate prototype testing is the recent trend in the automotive industry. Reducing the total vehicle development period with optimized output has been the major advantage of this new trend, fueled by increasing competition and shorter product life cycle. In this regard, Computer Aided Engineering (CAE) has taken a more significant role than ever in the vehicle development programs. Prediction of road noise in passenger cars is one of the important attributes to NVH (Noise Vibration Harness) Simulations. In the present work, CAE - NVH simulation of road noise is carried out on the finite element model of the vehicle, eliminating the costly and laborious test procedures & the process of awaiting information from various departments. One of the major challenges in these simulations are generating the load inputs for the structure-borne road noise in a cost and time saving method with accuracy. An alternative to the existing MBD/Test input method is explored in the present work. Enforced displacements in the frequency domain are generated using ISO 8608 standard road profiles and are used as input to the vehicle system. Time and cost of the total procedure is reduced drastically by this procedure with more than acceptable accuracy & correlation. The results are validated with the available test data & existing MBD CAE input methods of predicting the interior noise of the passenger cars."
"Prediction of Aeroacoustical Interior Noise of a Car, Part-2 Structural and Acoustical Analyses","One-way coupled simulation method that combines CFD, structural and acoustical analyses has been developed aiming at predicting the aeroacoustical interior noise for a wide range of frequency between 100 Hz and 4 kHz. Statistical Energy Analysis (SEA) has been widely used for evaluating transmission of sound through a car body and resulting interior sound field. Instead of SEA, we directly computed vibration and sound in order to investigate and understand propagation paths of vibration in a car body and sound fields. As the first step of this approach, we predicted the pressure fluctuations on the external surfaces of a car by computing the unsteady flow around the car. Secondly, the predicted pressure fluctuations were fed to the subsequent structural vibration analysis to predict vibration accelerations on the internal surfaces of the car. Finally, an acoustical analysis was performed to predict sound fields in the cabin by using particle velocities of sound on the interior surfaces of the car, predicted by the structural analysis. To transfer predicted surface data, such as pressure fluctuations, vibration accelerations and particle velocities of sound, from one simulation to another, we adopted a parallel coupling tool. As the second part of our research, this paper presents results of the structural vibration analysis and that of the acoustical analysis, together with those measured by wind tunnel tests. In our research, a light automobile, for which all the interior components were removed and the underfloor shape was simplified, was employed for a case study. The wind tunnel tests were performed with a freestream velocity of 100 km/h. Both the predicted interior surface accelerations and interior noise level agreed well with the measured equivalents up to 2 kHz."
Aero-Vibro-Acoustic Wind Noise-Simulation Based on the Flow around a Car,"Aim of the ongoing development of passenger cars is to predict the interior acoustics early in the development process. A significant noise component results from the flow phenomena in the area of the side window. Wind noise is a physical problem that involves the three complicated aspects each governed by different physics: The complex turbulent flow field in the wake of the a-pillar and the side mirror is characterized by velocity and pressure fluctuations. The flow field generates sound which is transmitted into the passenger cabin. In addition to that, it excites the structure, resulting in a radiation of structure-borne noise into the interior of the car. Therefore, the sound generation is governed by fluid dynamics of the air flow. The sound transmission through the structure due to vibrations is determined by structural mechanics of the body structure. The sound propagation inside the cabin is influenced by interior room acoustics. In the present work, different CFD simulations of the exterior flow were conducted to investigate the sound generation due to external air turbulence. For this purpose, a simplified model of an automobile was used. Additionally vibro and aeroacoustic simulations were conducted to solve the other two parts of the problem and to gain insight into the sound transmission into the passenger cabin."
The Application of Superelement Modeling Method in Vehicle Body Dynamics Simulation,"In this paper, we propose a method of dynamics simulation and analysis based on superelement modeling to increase the efficiency of dynamics simulation for vehicle body structure. Using this method, a certain multi-purpose vehicle (MPV) body structure was divided into several subsystems, and the modal parameters and frequency response functions of which were obtained through superelement condensation, residual structure solution, and superelement data restoration. The study shows that compared to the traditional modeling method, the computational time for vehicle body modal analysis can be reduced by 6.9% without reducing accuracy; for the purpose of structural optimization, the computational time can be reduced by 87.7% for frequency response analyses of optimizations; consistency between simulation and testing can be achieved on peak frequency points and general trends for the vibration frequency responses of interior front row floors under accelerating conditions. The results indicate that the method has good engineering value, and is suitable for the study of dynamics problems of vehicle bodies."
In-Cabin Aeroacoustics of a Full-Scale Transport Truck,"The noise generated by the flow of air past a transport truck is a key design factor for the manufacturers of these vehicles as the sound levels in the cabin are a significant component of driver comfort. This paper describes a collaboration between Volvo GTT and the National Research Council Canada to measure the in-cabin aeroacoustics of a full-scale cab-over tractor in the NRC 9 m Wind Tunnel. Acoustic instrumentation was installed inside the tractor to record cabin noise levels and externally to acquire tunnel background noise data. Using a microphone mounted on the driver’s-side tunnel wall as a reference to remove variations in background noise levels between data points, differences in cabin noise levels were able to be detected when comparing the tractor with different configurations. The good repeatability of the data allowed for differences of as little as 0.5 dB to be measured. A procedure to estimate the transfer function from the wall reference microphone to the cabin microphones was implemented which, though of limited success, provided insights into the acoustic environment of the test section. The main conclusion of this project is that aeroacoustic measurements can be carried out in the NRC 9 m Wind Tunnel in conjunction with an aerodynamic entry for full-scale transport trucks."
Vibration Test Machine and Operation Procedure,"This SAE Recommended Practice provides procedures, and information to conduct vibration (impact) tests on lighting devices and their components as well as other safety equipment used on vehicles."
Collision Deformation Classification,"The purpose and scope of this SAE Recommended Practice is to provide a basis for classification of the extent of vehicle deformation caused by vehicle accidents on the highway. It is necessary to classify collision contact deformation (as opposed to induced deformation) so that the accident deformation may be segregated into rather narrow limits. Studies of collision deformation can then be performed on one or many data banks with assurance that the data under study are of essentially the same type.1 The seven-character code is also an expression useful to persons engaged in automobile safety, to describe appropriately a field-damaged vehicle with conciseness in their oral and written communications. Although this classification system was established primarily for use by professional teams investigating accidents in depth, other groups may also find it useful. The classification system consists of seven characters, three numeric, and four alphameric, arranged in a specific order. The characters describe the deformation detail concerning the direction, location, size of the area, and extent which, combined together, form a descriptive composite of the vehicle damage. The individual character positions are referred to by column number for identification and computer storage compatibility as illustrated in Figure 1. The definition of each classification is provided in subsequent sections. An Appendix is also provided to assist in application and interpretation."
Integrated Mechatronic Design and Simulation of a Door Soft Close Automatic with Behavioral Models of Smart Power ICs,"Based on the example of a door soft close automatic the potential of integrated system simulation in the automotive systems development is demonstrated. The modeling approach is covering several physical domains like mechanics, electromagnetics and semiconductor physics. With adequate simplifying methods a time efficient model is generated, which allows system optimization in the concept phase. Time consuming redesigns can thus be minimized."
Highly Efficient Robust Optimization Design Method for Improving Automotive Acoustic Package Performance,"To consider the influence of uncertainty in the design process of automotive acoustic packages, the robustness of the acoustic packaging system performance must be improved, and the low-efficiency problem of the two-layer nesting robustness optimization model must be solved. This article proposes a highly efficient robustness optimization design method for improving the performance of the automotive acoustic package. First, the full vehicle model was established based on the statistical energy analysis method, and the accuracy of the model was verified through acoustic transfer function (ATF) testing. The parameters affecting the sound absorption and insulation performance of the key acoustic packaging parts were selected as the uncertain parameters, and their sensitivity was analyzed. The possibility degree method of interval numbers was introduced to convert the two-layer nesting robustness optimization model to a single-layer optimization model, and the efficient robust design of the automotive acoustic packaging was realized. The acoustic packaging parts of a sport utility vehicle (SUV) were analyzed and optimized using the proposed efficient and robust optimization method. After optimization, the total mass of the acoustic packaging parts decreased by 10.8%, the radius of the perturbation interval of the interior noise decreased by more than 25% compared with the initial value, and the robustness of the system greatly improved."
Strat-X,"Experiments in space can be expensive and infrequent, but Earth’s upper atmosphere is accessible via large scientific balloons, and can be used to address many of the same fundamental questions. Scientific balloons are made of a thin polyethylene film inflated with helium, and can carry atmospheric sampling instruments on a gondola suspended underneath the balloon that eventually is returned to the surface on a parachute. For stratospheric flights between 30 and 40 km above sea level, balloons typically reach the float altitude 2-3 hours after launch, and travel in the direction of the prevailing winds."
Access System Senses Finger Vibrations to Verify Users,"The market for smart security access systems is expected to grow rapidly, reaching nearly $10 billion by 2022. Today's smart security access systems mainly rely on traditional techniques that use intercoms, cameras, cards, or fingerprints to authenticate users. These systems require costly equipment, complex hardware installation, and diverse maintenance needs."
Smart Fabric Stores Information Without Electronics,"Conductive thread — embroidery thread that can carry an electrical current — often is combined with other types of electronics to create fabric that lights up or communicates. This thread also has magnetic properties that can be manipulated to store either digital data, or visual information like letters or numbers. This data can be read by a magnetometer, an inexpensive instrument that measures the direction and strength of magnetic fields, and is embedded in most smartphones."
Level Zero HERO,"Wrangler Rubicon has 10.9 in of ground clearance and industry-leading approach, departure and breakaway angles to uphold its heritage for off-road dominance. Okay, maybe the 2018 Jeep Wrangler could be considered SAE autonomy Level 0.5- after all, the all-new version of Jeep's icon does offer a couple of automated driver-assist features. If you must. But apart from that concession to contemporary development trends, the new Wrangler is unabashed in its dedication to the analog driving experience: It's updated, upgraded and more refined, but it's unquestionably the most elemental new vehicle of 2018. After all, name another all-new model that pridefully comes to market at the dawn of the automated-driving epoch with solid front and rear axles, a windshield that folds down and doors that come off."
Delayed Latching Mechanism,"Uncontrolled and rapid movement of equipment and people through security gates has been a major problem for security personnel. In situations pertaining to facility security, it is desirable to delay the passage of a person through an entrance or an exit for a small interval of time, such as several seconds or up to a minute. Often, authorization to proceed is provided by an electronic signal to unlock the passageway. Such electronic signals are initiated remotely by a person in authority, such as a guard in a control room viewing a security camera, or a person who verifies the identity of the requester through a two-way audio connection."
42V PowerNet in Door Applications,"This article describes the effects of a future 42V automotive electrical system on the vehicle electronics, focusing mainly on the consequences for power semiconductors and their associated technologies. Taking the example of a door module, it then shows how existing 14V loads can be operated on the 42V PowerNet and what advantages result for operation of adjusted 42V loads. The following different problem-solving approaches are presented for typical loads such as power windows, electrically positioned and heated outside mirrors, and central locking: Power windows: A test motor specially developed for the 42V supply is continuously operated directly from the electrical system using suitable power semiconductors. Central locking: A conventional 14V motor is operated at 42V, its operating point being set using pulse width modulation (PWM). Remaining door module: Smaller 14V mirror motors and the control electronics are supplied from a second 14V system. This second supply can be taken from the current 14V system or generated locally by appropriate switching regulators, or even by a central DC/DC converter from 42V."
Assessment of the Vehicle's Interior Wind Noise Due to Measurement of Exterior Flow Quantities,"The optimal styling of the exterior surface of a vehicle and its suspension system have a direct impact on interior wind noise. Both are determined in early project phases when no hardware prototype is available. Turbulent flows produce both external pressure fluctuations at the vehicle shell, known as hydrodynamic excitation, and sound waves, known as acoustic excitation. Hydrodynamic and acoustic sound sources are evaluated separately and relative to each other in the frequency domain in order to perform evaluations of different body shapes. The technical aim of the presented work is to investigate how acoustic quantities measured at the outside of a vehicle can be used to assess the influence of styling modifications to interior sound pressure level. The methodology is required to be capable of being integrated into the serial development process and therefore be quickly applicable. MAGNA STEYR Engineering has conducted extensive research to develop a method to ensure the best option is selected in the early project stages."
"Performance Test for Windshield Defrosting Systems for Off-Road, Self-Propelled Work Machines","This SAE Standard establishes uniform test procedures for the defrosting systems of off-road, self-propelled work machines used in construction, general purpose industrial, agricultural, and forestry machinery as referenced in table one of this document. It includes tests that can be conducted with uniform test equipment in commercially available laboratory facilities, as well as in an appropriate outdoor environment."
Windshield with Enhanced Infrared Reflectivity Enables Packaging a Driver Monitor System in a Head-Up Display,"Integration of a driver monitor system (DMS) in a head-up display (HUD) gives the monitor camera a continuous view of the driver’s face, since the driver always faces the road ahead. However, with both infrared (IR) illuminator and IR camera packaged in the HUD, reflectivity of the windshield is important at IR wavelengths used by the camera. Not only is windshield IR reflectivity important for a clear camera image of the driver’s face, but increasing windshield reflectivity also decreases the effect of ambient sunlight on the camera image of the driver’s face. We describe a method to measure windshield reflectivity, both for the 940 nm band used by a DMS, and for visible light for the HUD. The measurement method uses a fiber-optic spectrometer, two collimating lenses, and a method to compensate for sample tilt. The lenses are mounted on a stage that adjusts the height above the sample. As an example, this method was used to characterize an IR reflecting windshield, prepared for a prototype automotive HUD. At 940 nm, and 45° angle of incidence, the measured reflectivity is > 85% for unpolarized incident light. For visible light at 550 nm, and 62° angle of incidence, the measured reflectivity is 13.9% for both an IR reflecting windshield and for a reference windshield, for unpolarized incident light. The prototype windshield gives a good reflected image for the DMS IR camera and a good HUD image as seen by the driver. The method used to prepare this prototype windshield is suitable for high-volume production."
Passenger Car Side Door Latch Systems,"This SAE Recommended Practice establishes minimum performance requirements and test procedures for evaluating and testing passenger car side door latch systems. It is limited to tests that can be conducted on uniform test fixtures and equipment in commercially available laboratory test facilities. The test procedures and minimum performance requirements outlined in this document are based on currently available engineering data. It is intended that all portions of the document will be periodically reviewed and revised, as additional knowledge regarding vehicle latch performance under impact conditions is developed."
Access Systems for Off-Road Machines,"Minimum criteria are provided for steps, stairways, ladders, walkways, platforms, handrails, handholds, guardrails, and entrance openings which permit ingress to and egress from operator, inspection, maintenance or service platforms on off-road work machines parked in accordance with the manufacturer's instructions."
Sound Measurement—Off-Road Self-Propelled Work Machines Operator-Work Cycle,"This SAE Standard sets forth the procedures to be used in measuring sound levels and determining the time weighted sound level at the operator's station(s) of specified off-road self-propelled work machines. This document applies to the following work machines which have operator stations as specified in SAE J1116: • Crawler Loader • Grader • Log Skidder • Wheel Loader • Crawler Tractor with Dozer • Pipelayer • Dumper • Wheel Tractor with Dozer • Trencher • Tractor Scraper • Backhoe • Sweeper • Roller/Compactor • Hydraulic Excavator • Pad Foot Wheel Compactor with Dozer • Excavator and Wheel Feller-Buncher The instrumentation requirements and specific work cycles for these machines are described. The method used to calculate the time weighted average sound level at the operator station(s) is specified for Leq(5), or optional exchange rates, during continuous operation in a work cycle representing continuous medium to heavy work. The work cycles provide a repeatable reproduceable means to uniformly measure working machines against a “yard stick. A method to relate the time weighted average sound level at the operator station(s) to estimate operator sound exposure with part load work, supervision, and rest breaks is also provided."
Integrated CAE Methods for Perceived Quality Assurance of Vehicle Outer Panels,"Oil canning and initial stiffness of the automotive roofs and panels are considered to be sensitive customer ‘perceived quality’ issues. In an effort to develop more accurate objective requirements, respective simulation methods are continuously being developed throughout automotive industries. This paper discusses a latest development on oil canning predictions using LS-DYNA® Implicit, including BNDOUT request, MORTAR contact option and with the stamping process involved, which resulted in excellent correlations especially when it comes to measurements at immediate locations to the feature lines of the vehicle outer panels. Furthermore, in pursuit of light-weighting vehicles with thinner roofs, a new CAE method was recently developed to simulate severe noise conditions exhibited on some of developmental properties while going through a car wash. This paper introduces such a method to discuss Fluid Structure Interaction (FSI) approach using an Arbitrary Lagrangian Eulerian (ALE) formulation in LS-DYNA® for vehicle roof car wash boom noise prediction. This CAE method was developed to simulate force behavior from airflow as the car wash air blowers are expelling high speed air at the vehicle roofs during car wash. LS-DYNA® was proven an appropriate tool to precisely simulate popping noises by creating instantaneous local instabilities - recoverable/non-recoverable - and continuous fluttering of the roof. This paper additionally briefs the history of oil canning CAE method developments from inaccurate hand push evaluation to approaches using MSC Nastran® to Abaqus/Standard®, and then the final evolution to LS-DYNA® Implicit to provide optimized vehicle solutions."
New Trivial Principal Component Method: System Modeling,"Principal Component Analysis (PCA) is a powerful statistical technique used for understanding variation in the observed data and decomposing variation along eigenvectors, known as Principal Components (PCs), by considering variance-covariance structure of the data. Traditionally, eigenvectors that contain most of the variation or information are selected to reduce variables in data reduction. Eigenvalues of low magnitude are considered to be noise and often, not included in the dataset to accomplish dimensional reduction. Analogously, in Principal Component Regression (PCR), PCs with large eigenvalues are selected without considering correlation between the source variables and the dependent response. This inherent deficiency may lead to inferior regression modelling. While addressing this issue, an alternative to PCR is developed and proposed in this paper. In this method, a principal component associated with zero eigenvalue is termed Trivial Principal Component (TPC). This novel method involves the formulation of the TPC by including output response in the covariance matrix and then, extracting the Eigen-pairs. The TPC contains the relationship between the dependent response and the source variables and is used for extracting linear coefficients. In other words, the TPC is formulated to determine sensitivities taking into account correlation relationship between the output response and source variables. Example problems are presented to illustrate methodology and accuracy of the TPC method. Results of this method are applied on a practical production problem to make manufacturing changes for improved quality."
Experimental Studies on Different Actuator-Sensor Configurations of Active Control Systems for the Reduction of Noise and Vibration in Vehicles,"Current developments in the automotive industry such as downsizing, the use of cylinder deactivation and consistent lightweight construction increasingly enable the application of active control systems for the further reduction of noise and vibration in vehicles. In the past few years, different configurations of actuators and sensors for the realization of an active control system have been investigated and evaluated experimentally. Active engine mounts, inertial mass actuators and structural integrated actuators can be used to reduce either structural vibrations or the interior noise level. As a result, a variety of different topology concepts for the realization of an active control system arises. These can be divided into an active vibration control scenario, the direct influence of the sound field with loudspeakers or the application of structural actuators for the reduction of the interior sound pressure. In the latter case, microphones are used as error sensors for the active control system. With regard to the selection of a suitable actuator-sensor configuration special attention is required as several transfer paths for airborne and structure borne noise are existing. Furthermore, the attainable bandwidth of the applied control systems topology depends on the selection of a suitable actuator-sensor configuration and an adequate number of actuators and sensors in order to enable global control and to avoid local effects. This paper summarizes and compares different actuator-sensor configurations for the control of noise and vibration in vehicles. Beside the control performance, it highlights the electrical power requirements for the control of engine induced interior noise as a function of the selected actuator-sensor configuration."
Development of New Test Method for Compression Load and Permanent Deformation of Weather Strip,"The automotive weather strip performs functions of isolating water, dust, noise and vibration from the outside. To achieve good sealing performance, weather strip should be designed to have the high contact force and wide contact area. The compression load of weather strip is important for closing force in initial quality, but the permanent deformation is used to predict influx of wind noise over long periods of time. To check these accurately and easily, a new test method is demanded. So this paper introduces a new test method to predict the compression load and permanent deformation of 3D full vehicle by using ABAQUS. Uniaxial tension and creep tests were conducted to obtain the material data. The lab test for the permanent deformation was accelerated at high temperature during shorter time of 300 hours. Herein Proposed test method can provide accurate prediction under the different loading conditions and section shapes, and will also save time and cost."
Ford GT Body Engineering - Delivering the Designer's Vision in 24 Months,"The objective was to engineer a world-class supercar body that faithfully reproduces the 2002 Concept and pays homage to the 1960's road racer. The car had to be designed, developed and launched in 24 months, while meeting tough requirements for function, weight, occupant package and aerodynamics. Challenging features such as the cantilevered door, “clamshell” engine decklid and a deeply contoured hood were to be included. This paper will discuss how a dedicated team of enthusiasts can have a flexible approach to the engineering process, material selections and manufacturing processes to achieve the designer's vision in 24 months (Figure 1)."
Intrusion Resistance of Safety Glazing Systems for Road Vehicles,"This SAE Recommended Practice specifies an intrusion resistance test method for glazing systems installed in motor vehicles. Intrusion resistance performance is determined not solely by the glazing but also by the glazing attachment to the vehicle and by the vehicle structure. Therefore, the glazing/ attachment/vehicle structure must be tested as a single unit. This test determines intrusion resistance only. The test applies to those materials that meet the requirements for use as safety glazing materials as specified in Safety Standard ANSI/SAE Z26.1 or other applicable standards. The test applies to all installation locations."
Noise and Vibration Prediction and Validation for Off-Highway Vehicle Cab Using Hybrid FE-SEA Methodology,"Operator noise is an important aspect for noise and vibration of off-highway vehicles and a quieter cab is critical for the operator comfort. The noise level inside the cab is influenced by structural and acoustic transfer paths. In this paper, we used hybrid FE-SEA approach to consider both structural and acoustic transfer path as FEM and SEA methods individually face limitations in high and low frequencies respectively. A hybrid FE-SEA cab model was built to predict the structural and acoustic transfer functions. The analysis model was built with the systematic approach validated at each step with the laboratory test results. For the structural transfer function, structural excitations were applied at four cab mount locations and accelerations at various locations on the cab were validated. For the acoustic transfer function, the cab was excited with the volume velocity source inside the cab and sound power output of various panels were calculated and compared to the test results. Good agreement was observed between the simulation and the test results for both structural transfer path and acoustic transfer path."
Measurement and Presentation of Truck Ride Vibrations,"There are two ways to assess the characteristics of ride vibrations of a vehicle during its operation. Subjective evaluation and objective measurement. Subjective assessments of the ride vibrations experienced by drivers during ride evaluations are generally performed by a panel of drivers and/or passengers who are instructed to operate or ride a group of vehicles in a predetermined manner in order to subjectively assess the levels and characteristics of ride vibrations. Figures 6A through 6C show examples of subjective evaluation forms presently in use. The disadvantages of the subjective method include need for careful experimental design, need for statistically unbiased samples, complexity of human perceptions of vibrations, and difficulty in comparing qualitative data of vehicles evaluated at different times and/or by different groups of people. Often ride characterization is not an easy task using only qualitative or descriptive terms. Therefore, it is necessary and desirable to develop objective techniques to enable ride engineers and others to measure ride vibrations during ride assessment in a quantitative manner. This recommendation details a uniform method for the measurement of ride vibrations of all Class 7 and 8 commercial vehicles, including both combination vehicles and straight trucks. Vibrations are to be measured utilizing cab and seat-pad mounted accelerometers in vertical (z axis) and fore/aft (x axis) directions. The measurement in lateral direction (y axis) is optional as these vibrations from a ride assessment standpoint are seldom significant in commercial vehicles. Several currently utilized methods of displaying, analyzing, and combining the measured accelerations are presented. This recommendation does not make any statements concerning how well any of the objective ride measures will correlate to subjective evaluations of ride, nor does it deal with any limits or establish any desirable values for acceptable ride. It is recognized that objective ride evaluation methods have some disadvantages due to the complexities of these measures, sophistication of instrumentation and analysis techniques, etc. Therefore, it is recommended that technically trained personnel conduct the objective tests and analyze the data."
A Strategy for Developing an Inclusive Load Case for Verification of Squeak and Rattle Noises in the Car Cabin,"Squeak and rattle (S&R) are nonstationary annoying and unwanted noises in the car cabin that result in considerable warranty costs for car manufacturers. Introduction of cars with remarkably lower background noises and the recent emphasis on electrification and autonomous driving further stress the need for producing squeak- and rattle-free cars. Automotive manufacturers use several road disturbances for physical evaluation and verification of S&R. The excitation signals collected from these road profiles are also employed in subsystem shaker rigs and virtual simulations that are gradually replacing physical complete vehicle test and verification. Considering the need for a shorter lead time and the introduction of optimisation loops, it is necessary to have efficient and inclusive excitation load cases for robust S&R evaluation. In this study, a method is proposed to truncate and identify the important parts of the different road profiles that are often used for S&R physical verification and then merge them to develop one representative excitation load case. The criteria for signal truncation were based on the S&R risk and severity metrics calculated from the vibration response at the critical interfaces for S&R. the method was used in a case study involving the instrument panel of a passenger car. Results of the virtual simulation and the rig tests were compared with the complete vehicle test. The proposed synthesised signal generation strategy was validated by physical testing through measuring vibration signals. The results supported the possibility of replacing multiple S&R excitation signals with one single representative inclusive signal, while the quality of S&R risk prediction from the system response was maintained. The outcome of this work can lead to a more efficient physical and virtual S&R verification in the development process of passenger cars."
Coupled-SEA Application to Full Vehicle with Numerical Turbulent Model Excitation for Wind Noise Improvement,"Wind noise is becoming a higher priority in the automotive industry. Several past studies investigated whether Statistical Energy Analysis (SEA) can be utilized to predict wind noise. Because wind noise analysis requires both radiation and transmission modeling in a wide frequency band, turbulent-structure-acoustic-coupled-SEA is being used. Past research investigated coupled-SEA’s benefit, but the model is usually simplified to enable easier consideration on the input side. However, the vehicle is composed of multiple interior parts and possible interior countermeasure consideration is needed. To enable this, at first, a more detailed coupled-SEA model is built from the acoustic-SEA model which has a larger number of degrees of freedom for the interior side. Then, the model is modified to account for sound radiation effects induced by turbulent and acoustic pressure. Another concern about utilizing the coupled-SEA to wind noise development is the estimation of the turbulent and acoustic input. Several options are available for identifying the input, such as on-road data measurement, CFD simulation, and numerical turbulent model estimation. Because the turbulent model can be helpful to consider the countermeasure direction, the turbulent model application to coupled-SEA is considered. However, an appropriate turbulent model is still unclear whereas there are many kinds of turbulent models proposed. Due to this, as the next step, this paper performs a validation study in a wind tunnel to identify the suitable turbulent model for the wind noise simulation. Lastly, the entire method is validated with on-road measurements. A detailed coupled-SEA model under appropriate turbulent model input simulates test case conditions and its prediction accuracy is discussed along with a wind noise."
Prediction and Validation of Cab Noise in Agricultural Equipment,"To improve overall customer experience, it is imperative to minimize the noise levels inside agricultural equipment cab. Up-front prediction of acoustic performance in product development is critical to implement the noise control strategies optimally. This paper discusses the methodology used for virtual modeling of a cab on agricultural equipment for prediction of interior noise. The Statistical Energy Analysis (SEA) approach is suitable to predict high frequency interior noise and sound quality parameters such as articulation index and loudness. The cab SEA model is developed using a commercial software. The structural and acoustic excitations are measured through physical testing in various operating conditions. The interior noise levels predicted by the virtual model are compared with the operator ear noise levels measured in the test unit. The resultant SPL spectrum from SEA correlates well with the test. This model is used to optimize the noise control treatments and improve the NVH performance of the cab."
Theoretic Analysis of Factor to Affect Door Closing Force by Positioning Error of Assembly Fixture,"In order to analyze positioning errors of assembly fixture of car SANTANA 2000, a 3D CAD model of fixture is built in this paper. Six typical deviation models are defined on the basis of six points positioning principle for fixture. The assembly gap distribution between door and side frame is analyzed and the influence of different deviation patterns on assembly gap is studied, and the effect of assembly gaps on door closing force is evaluated meanwhile. The results show that positioning errors of door assembly fixture is one of the most important factors to affect the door closing force."
The Development of Testing Device for Compression Deformation of Automotive Door Weather-strip Seals,"Automotive door system weather-strip seals play a major role in determining door closing effort, isolating the passenger compartment from water and reducing the wind noise inside the vehicle. They are typically dual extrusion bulbs of sponge and dense rubber. The bulbs can be round, triangular or free form in shape with a height of approximately 15-30 mm. The special properties of dense and sponge rubber material are (1) High extensibility. (2) Low extensional and shear modulus. Dense rubbers are nearly incompressible. Sponge rubbers are, on the other hand, very compressible. (3) Nonlinear force vs. extension behavior. Because of the above-mentioned factors, the deformation of the automotive door weather-strip seal during the compression is very complicated. A testing set has been developed for obtaining compression deformation of the door weather-strip by using stereovision theory. Precision instruments of optical grating and force sensor are also integrated in this set. Force-displacement response characteristics of compression at varied speed can be controlled. This work will lay solid foundations for characteristic and structure as well as optimization design of the automotive weather-strip."
The Effects of Unsteady On-Road Flow Conditions on Cabin Noise: Spectral and Geometric Dependence,"The in-cabin sound pressure level response of a vehicle in yawed wind conditions can differ significantly between the smooth flow conditions of the aeroacoustic wind tunnel and the higher turbulence, transient flow conditions experienced on the road. Previous research has shown that under low turbulence conditions there is close agreement between the variation with yaw of in-cabin sound pressure level on the road and in the wind tunnel. However, under transient conditions, sound pressure levels on the road were found to show a smaller increase due to yaw than predicted by the wind tunnel, specifically near the leeward sideglass region. The research presented here investigates the links between transient flow and aeroacoustics. The effect of small geometry changes upon the aeroacoustic response of the vehicle has been investigated. It was found that sideglass pressures showed close agreement at all turbulence levels while surface sound pressure levels also showed similar behaviour under a wide range of on-road flow conditions. While the overall sideglass sound pressure level changed under the various yaw conditions, the change in shape of the frequency spectrum was less significant. Geometry changes made to a base vehicle reduced the sensitivity of the in-cabin noise to on-road turbulence, showing that shape-change can modify sensitivity to on-road turbulence."
NVH Challenges for Low Cost and Light Weight Small Cars,"In worldwide automotive markets, the migration of customers towards smaller cars having compact, fuel-efficient design is well established and accepted as an engineering challenge by global automotive OEMs. Tata Motors of India has established a precedent by developing an ultra low cost and light weight car (the Nano), and has thereby created a new market segment for such cars that are more affordable to most of the population. This is now becoming established as a brand of low cost, safe transport in both rural and urban market segments. Despite the market moving towards such compact, fuel-efficient designs, customers are unwilling to lose many of the vehicle attributes to which they have been accustomed in previous types of entry-level cars. Addressing this marketing requirement places some significant challenges before the designers of this type of car. This paper considers some of the fundamental technical challenges faced in delivering acceptable NVH performance in a light weight, low cost car. One of the most significant issues is the use of engines with lower cylinder counts than conventional cars, leading to strong impulsiveness and lower firing frequencies. These can become problematic when mounted in vehicle structures that have a high interior volume in proportion to their mass and are often not able to meet established norms for benchmark vibro-acoustic performance. Other matters considered include the high ratio of power train mass to total vehicle mass and the higher ratio of laden to un-laden mass. Such vehicles are also generally intended for manufacture by lower skilled workers in regions with little or no automotive assembly heritage, so they must be designed for ease of “right first time” assembly. Using the example of this product, some of the possible solutions to these challenges faced by the NVH team are examined. The paper will show that it is feasible to deliver market-acceptable NVH behavior despite the strong constraints inherent in such types of vehicle, by means of lean and innovative design."
Experimental Method Extracting Dominant Acoustic Mode Shapes for Automotive Interior Acoustic Field Coupled with the Body Structure,"For a numerical model of vibro-acoustic coupling analysis, such as a vehicle noise and vibration, both structural and acoustical dynamic characteristics are necessary to replicate the physical phenomenon. The accuracy of the analysis is not enough for substituting a prototype phase with a digital phase in the product development phases. One of the reasons is the difficulty of addressing the interior acoustical characteristics due to the complexity of the acoustical transfer paths, which are a duct and a small hole of trim parts in a vehicle. Those complex features affect on the nodal locations and the body coupling surface of acoustic mode shapes. In order to improve the accuracy of the analysis, the physical mechanisms of those features need to be extracted from experimental testing. The accuracy of the vibro-acoustic coupled system model for the low frequency range depends on how accurately modal characteristics are represented at the input, output, and the structure-acoustic coupling surface. Therefore, this study focus on extracting the detailed acoustic mode shapes on the coupling surface for the improvement of the model accuracy. The non-linear least square method as the one utilized in the previous study was applied to the new test data sets of an actual vehicle. In the previous study, it had one remaining issue, which was how to extract acoustic mode shapes in the frequency range of higher damping and higher acoustic modal densities. In order to solve this issue, the number of acoustic excitation was increased considering acoustic mode shapes. The eight loudspeakers were utilized as an acoustical excitation to excite acoustic modes evenly in the acoustic interior dimensions for higher frequency. With the results of this testing, the acoustic modes of an actual vehicle with heavy damping were accurately extracted as the complex mode shapes of no phase lag between nodes, which looks similar the un-coupled normal modes without rotation in animation up to 200Hz. The synthesized FRFs were replicated well with only the extracted several dominant acoustic mode shapes."
Body Induced Boom Noise Control by Hybrid Integrated Approach for a Passenger Car,"Vehicle incab booming perception, a low frequency response of the structure to the various excitations presents a challenging task for the NVH engineers. The excitation to the structure causing boom can either be power train induced, depending upon the number of cylinders or the road inputs, while transfer paths for the excitation is mainly through the power train mounts or the suspension attachments to the body. The body responds to those input excitations by virtue of the dynamic behavior mainly governed by its modal characteristics. This paper explains in detail an integrated approach, of both experimental and numerical techniques devised to investigate the mechanism for boom noise generation. It is therefore important, to understand the modal behavior of the structure. The modal characteristics from the structural modal test enable to locate the natural frequencies and mode shapes of the body, which are likely to get excited due to the operating excitations. The critical transfer paths for the excitation through the structure have been identified with the help of transfer path analysis, while running mode analysis indicate the dynamic behavior of the structure due to the excitation. Similarly, the acoustic modal analysis describes the fundamental acoustic modal characteristics of the cabin cavity. The introduction of the experimental running mode inputs of the structure to the acoustic finite element model makes the hybrid analysis possible. The panel contribution analysis focuses on the components that have the significant contribution in the booming noise for in-phase as well as out of phase panels. The modifications revealed from the systematic study by hybrid approach, has led to substantial reduction in the booming noise both objectively and subjectively. This paper also describes the improvements suggested to reduce the boom noise."
High-Frequency Time Domain Source Path Contribution: From Engine Test Bench Data to Cabin Interior Sounds,"This work presents an application of airborne source path contribution analysis with emphasis on prediction of wideband sounds inside a cabin from measurements made around a stand-alone engine. The heart of the method is a time domain source path receiver technique wherein the engine surface is modeled as a number of source points. Nearfield microphone measurements and transfer functions are used to quantify the source strengths at these points. This acoustic engine model is then used in combination with source-to-receiver transfer functions to calculate sound levels at other positions, such as at the driver's ear position. When combining all the data, the in-cabin engine sound can be synthesized even before the engine is physically installed into the vehicle. The method has been validated using a powertrain structure artificially excited by several shakers playing band-limited noise so as to produce a complicated vibration pattern on the surface. First the excited structure is studied alone; next a vehicle cabin was lowered onto the structure without touching. As a result we can compare the combination of using only in-vehicle operating/transfer data or using powertrain only operating data and in-vehicle transfer data for synthesizing interior sounds. Very good agreement between the two procedures was obtained and comparable to the actual sound measured inside the cabin during operation. In addition to verifying the above procedure, the same near-field microphone setup, whether powertrain alone or with cab on top, can be used to assess the radiated sound power from the vibrating structure. The procedure is outlined and the obtained sound power spectra are validated against a standardized hemisphere sound power measurement showing very good agreement in general."
Further Development of the PNCA: New Panel Noise Contribution Reference-Related (PNCAR),"The Panel Noise Contribution Analysis (PNCA) is a well-known methodology for an airborne Transfer Path Analysis (TPA) in car interior. Pressure contribution from the individual panels at a reference point can be very accurately calculated. Acoustic Trim package treatment can therefore be optimized in terms of frequency and panel area which saves money and time. The method uses only one type of sensors so called particle velocity probes for measuring source strength as well as transfer function (with a reciprocal measurement). Traditionally the PNCA makes use of a big amount of probes at fixed points (about 50) hence non-stationary conditions can be measured as well. Typically the measurement is performed in 3 sessions resulting in 150 individual panels. Because of the low spatial resolution the method can only be used at mid-low frequency range. The new Panel Noise Contribution Analysis Referenced (PNCAR) implements a new post-processing technique which uses a reference sensor in order to extract the relative phase information for the individual panel and frequency of interest. This technique makes it possible to use a limited amount of probes for measuring a whole car interior. Typically 11 probes are used in 11 sessions. Consequently, the methodology becomes more robust and commercially more affordable than conventional PNCA. A real measurement in driving condition was done on the highway in order to validate the methodology. Two different approaches to apply the theory derivations are compared and discussed."
The influence of A-pillar obscuration/location on driver visibility,"During the early phase of vehicle development, one of the key design attributes to consider is visibility for the driver. Visibility is the ability to see one’s surrounding environment while they are driving. Therefore, it is one of the key requirements to be considered during the vehicle design. Certain vehicle characteristics such as the size of windshield and the design of the pillars influence the perception of visibility for the driver. One specific characteristic influencing satisfaction is A-pillar obscuration and location, which is the subject of this paper. The objective of this project is to analyze the relationship between the A-pillar obscuration/location with the driver satisfaction under real world driving conditions, based on research, statistical data analysis and dynamic clinics. Other influences, such as the position of the occupant in the seat was also studied and captured in this paper."
Vehicle Passenger Door Hinge Systems,The scope of this SAE Recommended Practice is to establish recommended uniform test procedures and minimum static load requirements for vehicle passenger door hinge systems. Tests are described that can be conducted on test fixtures and equipment in laboratory test facilities. The test procedures and minimum performance requirements outlined in this document are based on currently available engineering data. It is intended that all portions of the document be periodically reviewed and revised as additional knowledge regarding vehicle hinge system performance under impact conditions is developed.
3D Simulation Methodology to Predict Passenger Thermal Comfort Inside a Cabin,"The vehicle Heating, Ventilation and Air conditioning (HVAC) system is designed to meet both the safety and thermal comfort requirements of the passengers inside the cabin. The thermal comfort requirement, however, is highly subjective and is usually met objectively by carrying out time dependent mapping of parameters like the velocity and temperature at various in-cabin locations. These target parameters are simulated for the vehicle interior for a case of hot soaking and its subsequent cool-down to test the efficacy of the AC system. Typically, AC performance is judged by air temperature at passenger locations, thermal comfort estimation along with time to reach comfortable condition for human. Simulating long transient vehicle cabin for thermal comfort evaluation is computationally expensive and involves complex cabin material modelling. Lattice-Boltzman (LBM) based PowerFLOW solver coupled with Finite element based PowerTHERM solver is employed in this study to simulate long transient soak and Cooldown along with thermal comfort. Additionally, the human thermal physiology is modeled, to account for subjective evaluation of the in-cabin thermal environment. Berkeley comfort model library is available in PowerTHERM. The model takes care of the vasodilation and vasoconstriction effects, based on the external human ambient, along with the effects of clothing and the passenger metabolic rate. Vasodilation and vasoconstriction regulate the blood flow by widening or narrowing the blood vessels depending upon the warm or cold ambient conditions. LBM based flow solver is used to predict convective heat transfer phenomenon for both the exterior and interior of the cabin. The conduction and the radiation effects including the solar loading were solved using PowerTHERM. Physical test is conducted under controlled ambient conditions of climate chamber for a car cabin. Results from the coupled approach correlates well the test results for both hot soaked and cool-down conditions with a significant reduction in simulation time. During the cabin cool-down phase, passenger thermal comfort is predicted using Predictive Mean Vote. This process is further used to study the effect of change in properties of the glazing surfaces for predicting cabin thermal environment like heat ingress and cabin surface and air temperatures. Thermal comfort is also predicted and compared with baseline design. Glazing material sensitivity is carried out for absorbing and reflective glass material and its impact on cabin surface and air temperature and thermal comfort is predicted here. This process is deployed and found useful for predicting vehicle level thermal comfort."
Systematic CAE Approach to Minimize Squeak Issues in a Vehicle Using Stick-Slip Test Parameters,"Due to recent advancements in interior noise level and the excessive use of different grade leathers and plastics in automotive interiors, squeak noise is one of the top customer complaints. Squeak is caused by friction induced vibration due to material incompatibility. To improve costumer perception, interior designs are following zero gap philosophy with little control on tolerances leading to squeak issues. Often manufacturers are left with costly passive treatments like coatings and felts. The best option is to select a compatible material with color and finish; however, this will reduce the design freedom. Material compatibility or stick-slip behavior can be analyzed with a tribology test stand. However, this test is performed on a specimen rather than actual geometry. There were instances, when a material pair was found incompatible when tested on a specimen, but never showed any issue in actual part and vice versa. Thus, interface stiffness and system sensitivity between the parts are important while analyzing the stick-slip behavior before implementing any solutions. To improve the process vehicle interiors are analyzed by CAE methods to evaluate stick-slip behavior by utilizing SSP test data. The CAE methodology considers wide range of input load cases, global and local system sensitivity, local geometries, and connection stiffness to get realistic results from squeak simulations, which otherwise not possible with stick-slip testing. In the present study, “no relative movement no squeak” philosophy is used to drive the design of interior trims to avoid squeaks. Squeak risk at interface is evaluated by comparing in-plane relative displacement with ‘1/ IRmax’ value obtained from stick-slip testing. Meaningful information has been extracted through linear static analysis to understand the influence of preloading on contact forces between the interfaces. This approach has improved the squeak prevention process in product development without changing materials or usage of passive treatments."
"Truck Front Cabin Mount Tuning for Cabin Noise Boom, Overall Interior Noise and Vibration Reduction","In today’s automobile industry refined NVH performance is a key feature and of high importance governing occupant comfort and overall quality impression of vehicle. In this paper interior noise and vibration measurement is done on one of the light truck and few dominant low frequency noise booms were observed in operation range. Modal analysis was done for the cabin at virtual as well as experimental level and few modes were found close to these noise booms. Vibrations were measured across the cabin mounts and it was found that the isolation of front mounts is not effective at lower frequencies. Taking this as an input, the mount design was modified to shift the natural frequency and hence improve the isolation behavior at the lowest dominant frequency. This was followed by static and dynamic measurement of the mounts at test rig level to characterize the dynamic performance and stiffness conclusion. Finally the interior noise and vibration measurement is carried out on truck fitted with selected mounts and substantial vibration, overall noise reduction and drastic boom noise reduction was achieved. This paper takes up a real-time noise scenario, its root cause analysis and establishment of final solution for same. It covers various activities like noise, vibration measurement and analysis, virtual and experimental modal evaluation, mount transmissibility evaluation followed by design and tuning for corrects stiffness, and finally verification at rig and vehicle level. Hence this works runs through complete flow of NVH development cycle. The cabin mount design patent registration is approved."
Electromagnetic Analysis of Permanent Magnet Brushed DC Motor for Automotive Applications—Part 1,"Permanent magnet brushed DC (PMBDC) motors are mostly preferred in many automotive applications because of better power density and easier control. Five different automotive applications such as electric parking brake (EPB), power seat, power window, sunroof drive, and tire air pump are chosen and discussed in this paper. A step-by-step electromagnetic analysis is carried out for all the designed models. Low-cost ferrite-based magnets are used for cost reduction keeping the efficiency as high above 77% in all the models. Comparison on performance and cost are discussed in the conclusion section."
Reinforcement of Low-Frequency Sound by Using a Panel Speaker Attached to the Roof Panel of a Passenger Car,"The woofer in a car should be large to cover the low frequencies, so it is heavy and needs an ample space to be installed in a passenger car. The geometry of the woofer should conform to the limited available space and layout in general. In many cases, the passengers feel that the low-frequency contents are not satisfactory although the speaker specification covers the low frequencies. In this work, a thin panel is installed between the roof liner and the roof panel, and it is used as the woofer. The vibration field is controlled by many small actuators to create the speaker and baffle zones to avoid the sound distortion due to the modal interaction. The generation of speaker and baffle zones follows the inverse vibro-acoustic rendering technique. In the actual implementation, a thin acrylic plate of 0.53x0.2 m2 is used as the radiator panel, and the control actuator array is composed of 16 moving-coil actuators. The shape of the desired speaker zone is an ellipse, and the required amplitude of this piston source is pre-calculated to satisfy the desired sound radiation at the ear position. The gain of the actuator array to properly generate the desired vibration field is obtained by solving an inverse problem constructed by the transfer mobility between each actuator and field point on the plate. For the recruitment of the low-frequency deficiency of human auditory characteristics, the desired sound spectrum is set to follow the equal-loudness contour of 40 phons. It is confirmed that the woofer in a car can be replaced by the developed panel speaker."
Linear Impact Procedure for Occupant Ejection Protection,"The objective of this document is to enhance the test procedure that is used for ejection mitigation testing per the NHTSA guidelines as mentioned in the FMVSS226 Final Rule document (NHTSA Docket No. NHTSA-2011-0004). The countermeasure for occupant ejection testing is to be tested with an 18kg mass on a guided linear impactor using the featureless headform specifically designed for ejection mitigation testing. SAE does not endorse any particular countermeasure for ejection mitigation testing. However, the document reflects guidelines that should be followed to maintain consistency in the test results. Examples of currently used countermeasures include the Inflatable Curtain airbags and Laminated Glass. The testing procedure is as follows: 1 Determine the daylight opening 2 Identify target locations per the FMVSS226 Final Rule §5.2 a Target locations for all windows and daylight openings b Perform the target elimination process c Reconstitute the targets 3 Determine the zero-plane 4 In case of advanced glazing, determine if the glazing has to be part of the test and pre-brake it at a 75mm offset a If yes, than follow the procedure for pre-breaking the laminated glazing 5 Run the test a At 5.6m/s with a 1.5s delay b At 4.4m/s with a 6.0s delay"
Buffeting Noise Characteristics and Control of Automobile Side Window,"The computational fluid dynamics (CFD) software STAR-CCM+, Large Eddy Simulation (LES) method, and the Dynamic Smagorinsky-Lilly sub-lattice Model (DSLM) are used to study the buffeting noise characteristics of automobile side windows. Buffeting noise control methods are studied, and a comparison with experimental data verified the correctness of the simulation. Results show that periodic vortexing of the window opening area causes the strong pressure pulsation in the passenger compartment, and the combined effect of two mechanisms, namely, acoustic feedback and Helmholtz resonance, generates the buffeting noise. The sound pressure level (SPL) of buffeting noise produced by opening only the front window is lower than that of the rear window; Adding a rear mirror convex structure and a rain baffle structure reduces the buffeting noise SPL of the front window by 4.5 dB and 7.8 dB, respectively; Adding a convex structure and a non-smooth structure in the B pillar reduces the buffeting noise SPL of the rear window by 3.8 dB and 2.2 dB, respectively."
Analyzing Effects of Upperbody on Road Noise of Platform-Sharing Vehicles,"Platform sharing is widely used for reducing time and cost of vehicle development. It has been believed that vehicles that employ the same platform show similar performances of noise and vibration. Recently, however, it is observed that two vehicles that share the same platform present a noticeable difference in road noise. The structural difference between the two vehicles is located only at the upperbody of a Body In White (BIW). In order to investigate the effects of the upperbody on the road noise, several analyses such as (1) input point stiffness, (2) noise transfer function (NTF), and (3) road noise are performed using finite element (FE) models of the vehicles. As a result, it is found that the upperbody affects the NTF of the trimmed body and the road noise, which explains the dissimilarity of the road noise for the two vehicles. A novel method based on equivalent radiated power (ERP) is proposed to assess the upperbody. It is shown that analysis results obtained using the method show good correlation to the NTF of the trimmed body, which determines the road noise. Thus the proposed method can be used to assess an upperbody and predict the road noise of platform-sharing vehicles in the early stage of vehicle development."
An Aspect of Noise Vibration and Harshness Issues in Electric Vehicles,"Electric vehicles (EVs) are gaining ground more recently. New powertrains like electric and hybrid come with new noise, vibration, and harshness (NVH) issues previously unknown. A new approach to acoustic engineering is required to study NVH issues in EVs. The two primary dominant sources in an internal combustion engine (ICE) are engine noise due to combustion, and exhaust noise would not be there for EVs. EVs are less noisy, but several motor or battery cooling noises are encountered during design and validation. NVH is an indispensable part of subsystem integration in the EV powertrain. This article deals with various noise issues generally observed in EVs and their possible treatment to achieve the comfort car, satisfying customer expectations. The NVH-related problems for EVs are categorized into five categories: motor, wind, road, auxiliary, and other noises like integration. A detailed study of each category/problem type and NVH-suppression methods are discussed. The selection of powertrain mount architecture and its impact on load transfer and crash performance are also presented in this article. A balancing approach is required for NVH, durability, and crash requirements."
Acoustical Materials: Solving the Challenge of Vehicle Noise,"For a limited time only, SAE is offering a 20% discount off the list price of $70. Purchase today for $56. What is acoustics? What is noise? How is sound measured? How can the vehicle noise be reduced using sound package treatments? Pranab Saha answers these and more in Acoustical Materials. Acoustics is the science of sound, including its generation, propagation, and effect. Although the propulsion sources of internal combustion engine (ICE) vehicles and electric motor-powered vehicles (EV) are different and therefore their propulsion noises are different, both types of vehicles have shared noise concerns: Tire and road noise Wind noise Vehicle noise and vibration issues have been there almost from the inception of vehicle manufacturing. The noise problem in a vehicle is very severe and is difficult to solve only by modifying the sources of noise and vibration. Sound package treatments address the noise and vibration issues along the path to reduce in-cabin noise. In Acoustical Materials, readers will grasp the science of reducing sound and vibration using sound absorbers, sound barriers, and vibration dampers. Sound provides information on the proper operation of the vehicle, but if unchecked, can detract from the consumer experience within the vehicle and create noise pollution outside the vehicle. Acoustical Materials provides essential information on the basics of sound, vehicle noise source, how these are measured, how vehicle owners perceive sound, and ultimately, how to solve noise problems in vehicles using sound package materials."
Influence of Inner Panel Structure in Overall Liftgate Performance,"Prevailing global industry has set an environment that fosters the search for new procedures, technology and/or knowledge that allows time reduction in vehicle development and, at the same time, to offer the best strength and reliability characteristics to the customers. Constant improvement mindset is applied to those systems that yield the highest interaction with the final user, among those, it is paramount to take notice of systems like the vehicle closures (such as liftgates, hood, doors, etc.). In automotive industry, the efforts to comply with high standards are often focused to incorporate new materials, which are resistant and lightweight, on the other hand, this project explores the liftgate behavior from a more fundamental standpoint, which is the geometry and how it is related to the requirements that the liftgate should comply with. In this article, a research was conducted to establish which components have a high influence in the structural integrity of the liftgate, using as a starting point the structural testing’s that are performed to sign off the closures design during the product development stage. Furthermore, a comparison analysis between different liftgate structures, stand out the geometric design patterns of the interior panel of the liftgate that is present in the hatchback and sport utility vehicles. Finally, this project includes optimization proposals that determined the inner panel geometric form that enables the liftgate to comply with the structural requirements and comparison of the liftgate assessments results between the commonly used profiles across the industry."
The 747-400 Dreamlifter - Swing Tail Door Alignment and Latch Mechanism,"One essential feature of the 787 production system is the 747-400 Large Cargo Freighter (LCF), also known as the Dreamlifter,[1] and its ability to quickly and efficiently transport large components from global manufacturing locations to the final assembly site in Everett, Washington. This unique airplane has a tail section (Swing Tail) that opens to allow cargo loading. Quickly loading and unloading cargo is largely dependent on the reliable operation of the integral swing tail door alignment and latching systems. The swing tail door is approximately 23 feet horizontally by 29 feet vertically in size. The alignment and latching systems are required to function in a wide range of environmental conditions including temperature extremes and high winds. At the same time, these systems must ensure that flight loads are safely transmitted from the tail to the airplane fuselage without inducing undue fuselage preloads and without excessive play in the latching system. These requirements presented a developmental challenge that called for an innovative solution for adjustment of the latching and alignment mechanisms."
Evaluating Self-Unlocking Doors in Rollover Accidents using a Shock Testing Machine,"Automotive manufacturers often rely upon features such as automatic locking to enhance the security and crashworthiness of doors in rollover accidents. This can be verified in warnings conveyed to vehicle owners through some owner's manuals. At the present time, there are no requirements on the dynamic performance of door locking systems within the Federal Motor Vehicle Safety Standards (FMVSS), although some static inertia requirements exist for latch systems. Field accident investigation and laboratory testing has revealed that some locked doors can self-unlock in rollover accidents when a vehicle sustains a roof impact. Using standard laboratory shock testing machinery, the acceleration boundaries required to trigger self-unlocking have been mapped for some sample doors. Impact pulses of surprisingly low levels of acceleration, when combined with sufficient duration have been found to trigger this response. Furthermore, two entirely different failure mechanisms have been identified and documented thus far. One failure mode results directly from inertial triggering of the locking system; this mode is anticipated by FMVSS. The second failure mode is the unexpected consequence of the vibratory response of the lock system linkage. This failure mode has not yet been recognized in the safety literature. This paper presents the findings of a field accident investigation where self-unlocking was believed to have occurred as well as test data from doors exhibiting the two different self-unlocking mechanisms."
Investigation of Crash Impact Induced Oscillatory Response of Elements of Automotive Latch Systems,"Vehicle door closure systems often include self-balancing double pendulum mechanisms. For example, the counterweight in the outside handle assembly is used to reduce handle motion under inertia loadings occurring during crash events. The system is configured in such a way that the inertia forces developed during a crash are applying opposite moments to each of the pendulums (i.e., to the handle and the counterweight). Investigation of crash impact induced oscillatory response of such mechanisms is presented in this paper. A comprehensive dynamic model is developed that captures all essential characteristics of the double pendulum mechanism. An important aspect of the model is its discontinuous nature due to potential impacts between both pendulums and between one of the pendulums and the base part. Analytical conditions of self-balancing of the double pendulum system are formulated and used to provide an insight into the principles of self balancing. During dynamic simulations of the system, high frequency / high acceleration amplitude oscillatory motion of the base part provides inertia input to the system. It is shown that the double pendulum systems usually respond to such excitation with irregular motion. A methodology has been developed to study this system behavior and to analyze the resulting motion of the system. The multi-level analysis presented in the paper is used to investigate the conditions under which the system may not respond to external excitations, and to quantify the irregular response of the system when it does. The sensitivity of the solutions of the dynamic model to variation of system parameters and input characteristics is also addressed in the paper."
Testing and Modeling of Elevator Door Retention During Hallway Applied Lateral Loads,"Most do not consider there to be a risk in pushing on, bumping into or falling against an elevator door from the hallway side. However, the lack of the elevator cars presence alone, and the potential for severe injury or even death make this seemingly mundane situation potentially critical. Standards exist relative to such situations, and past and current designs attempt to account for this possibility, still people get injured interacting with these doors every year. In order to evaluate a real-world elevator door system's ability to withstand the quasi-static and impactive loads that can be placed on it by the general public during its life, both intentionally and unintentionally, a predictive tool is needed. This work represents the combination of empirical laboratory testing and numerical modeling of a typical elevator door system exposed to quasi-static and dynamic loading. The test procedures and methodology employed in this work provided repeatable and reliable results in quasi-static and dynamic testing. Numerical simulation using MADYMO established a robust and accurate quasi-static model of a primary door failure mode. The quasi-static MADYMO model can be used for quasi-static loading at any height of load application on the door and at any gib engagement depth up to full engagement with reliable and repeatable results. The dynamic MADYMO model showed accuracy at the 3 mm (0.12 in.) gib engagement depth at any contact height and any contact speed. A preliminary 6 mm (0.24 in.) gib engagement depth dynamic model has been verified for full-mass impacts of up to 1.5 m/s (4.8 ft/s)."
DRE NVH Contribution Analysis of Vehicle Cavity Fillers - NVH Target Setting Process,"The goal of this study is to measure the Noise, Vibration and Harshness (NVH) performance of passenger vehicle cavities under different drive conditions. Until now, little attention has been given to the impact of NVH performance of cavity fillers with respect to the driver's perception. To further understand this phenomenon, a four door sedan was instrumented with several microphones placed within different vehicle cavities. After instrumentation, the vehicle was tested under various road conditions; cruise, idle, street run, rough road and wide open throttle. The resulting data shows that there is a substantial noise presence in the hinge pillar and lower rocker cavities for all test conditions. The data also provides a means to rank the importance of the sound contribution of each vehicle cavities with respect to other cavities. To understand the NVH contribution of individual cavities to the driver's perception, the vehicle was placed inside a semi-anechoic chamber. The goal was to compute the transfer function of each cavity with respect to the driver's ear (DRE). The individual transfer functions could have been calculated by placing the random noise generator within each cavity while measuring the response at the DRE. This technique would have required several iterations of moving the noise generator from cavity to cavity. However, using the reciprocity concept, the noise generator can be placed at the DRE and the responses at all cavities can be measured simultaneously. Finally, having the road data along with all transfer functions, the relative importance of each cavity was determined with respect to the driver's ear. This methodology would enable vehicle manufacturers to understand the importance of cavity fillers to the vehicle's overall NVH performance. This technique would also help to optimize the application and provides NVH target setting goals for the vehicle cavity fillers."
Numerical Investigation of the Transmission Loss of Seals and Slits for Airborne SEA Predictions,"Seals and slits are often an important transmission path for vehicle interior noise at mid and high frequencies, and they are therefore often included in system level SEA models of interior noise. The transmission loss of seals and slits in such models is typically either measured experimentally or predicted using simple analytical models. The problem with the former is that it is expensive to investigate different design options using test; the problem with the latter is that simple analytical models often do not contain enough detail. The objective of this paper is therefore to investigate how much detail is needed in order to predict the transmission loss of typical slits and seals. Typical door seals are not directly exposed to exterior and interior sound fields, but instead are inserted in complicated “channel” sections formed by the door and pillar or rail structures. This study is therefore divided in two parts. The first part focuses on the effect of the channel (a “slit” type aperture between two acoustic spaces). The acoustic performance of various slits is investigated using fast 3D numerical models based on the Hybrid FE-SEA method. The use of this method makes it possible to diagnose the parameters controlling the transmission loss of a slit or seal across a broader frequency range than is possible with standard numerical methods such as BEM. The second part of the paper focuses on the transmission loss of the seal itself (with and without the presence of the channel). The sensitivity of the transmission loss to the deformation of the seal is also investigated (the deformation of the seal is predicted using a full non-linear deformation/contact analysis)."
Practical Application of Six Sigma with a Focus on Transmitted Variation – A Door Check Arm Opening Effort Case Study,"This paper presents an approach for Six Sigma strategies to reduce the occurrence of failure mechanisms. In general terms, there are two ways to reduce the failures: a) shifting or tuning - DMAIC approach or b) shrinking - DCOV approach. When shifting or tuning, we move the mean output away from the failure mode boundary and when shrinking, we reduce the variability of the output. Also, the paper illustrates with a case study - Cargo truck door opening effort check arm - where demand and capacity distributions had its distance to failure mode increased leading to high-quality low-cost alternative in vendor tooling."
Simulation of Outer Door Handle and Latch Responses in Side Impact using Component Test Methodology,"A dynamic component test methodology using a door sub-system was developed to simulate the outside door handle/latch responses (accelerations and deformations) as in a full-vehicle NHTSA FMVSS 214 side impact test. The test methodology consists of a door sub-system (with door inner components) which is allowed to pivot by means of a hinge at the top of the door. The lateral structural load path affecting the door/rocker response was accounted and simulated (obtained from full-vehicle FE analysis) in this methodology by means of an energy absorbing material (Aluminum honeycomb) of predetermined stiffness. A bullet sled simulating the Moving Deformable Barrier (MDB) surface and stiffness at the same relative location to the door/rocker (as in full-vehicle test) strikes the stationary hinged door at an initial velocity of approx. 30 mph (longitudinal component of crab cart velocity of 33.5 mph). Upon impact, the door sub-system rotates about the hinge simulating both the acceleration at the outer handle and latch, and overall deformation of the door. The front door responses (acceleration and velocity) near outer handle and latch from the component test methodology are compared to full-vehicle for validation."
Development of Door Module Plate with Long-fiber-reinforced Thermoplastic Polypropylene,"These days, many new applications for long-fiber-reinforced thermoplastic Polypropylene (PP-LFT) have been coming in the worldwide automobile market. Main issue of this paper is to explain how PP-LFT door module plate was developed, which processes were executed, and what kind of advantages we can get, once it is used as door module plate. Some of steel parts in the car have been changed to the reinforced PP-LFT with weight-saving. Change of material can make modularity more efficient, and then improvement of manufacturing process results in cost-saving. Stress analyses and MoldFlow analyses have been performed to choose the optimized conditions and a product model. Then various tests including waterproof test, drop-weight test and stiffness test have been executed to check if the weight-reduction is suitable for mass-production. PP-LFT door module plates including 40% glass-fiber were used in this paper using above mentioned methods, and, as a result, it is proved to get 21.5% weight reduction of plate and 12% reduction of door module assembly versus conventional steel module plates."
CAE Virtual Door Slam Test for Plastic Trim Components,"Visteon has developed a CAE procedure to qualify plastic door trim assemblies under the vehicle door slam Key Life Test (KLT) environments. The CAE Virtual Door Slam Test (VDST) procedure simulates the environment of a whole door structural assembly, as a hinged in-vehicle door slam configuration. It predicts the durability life of a plastic door trim sub-assembly, in terms of the number of slam cycles, based on the simulated stresses and plastic material fatigue damage model, at each critical location. The basic theory, FEA methods and techniques employed by the VDST procedure are briefly described in this paper. Door trim project examples are presented to illustrate the practical applications and their results, as well as the correlation with the physical door slam KLTs. The successful application of CAE virtual KLT has demonstrated that VDST can reduce product development time and cost, by evaluating and improving the durability of plastic door trim components at early design stage, before a prototype is made and physically tested."
An Application of Car Crash Test Technology to a Causal Investigation of a Revolving Door Accident,"On March 26, 2004, a fatal accident occurred when the head of a 6-year-old child was trapped in a large revolving door in a high-rise building in Tokyo. To investigate the cause of the accident, Prof. Yotaro Hatamura, representing Hatamura Institute for the Advancement of Technology, gathered experts in various fields including architecture and door manufacture, and initiated the “Door Project,” with the cooperation of the building company. Nissan Motor Co. participated in this project, and conducted load measurement tests on various doors. Applying car crash test technology, including production of special door test dummies and high-speed photography, it was possible to simulate the accident while taking human movement into account. As a result, we obtained important data for accident cause investigation. In this paper, we report the results of application of car crash test technology through an introduction of test results on various doors, and envisage the possibility of future contribution of this technology to man-machine safety issues."
Modeling of Door Slam Noise Index by using Sound Quality Metric,"Door slam noise is very important sound, because Door Slam noise gives a big effect in high-class feeling of vehicle and brand identity. But it is very difficult to analyze door slam noise by traditional analysis and overall sound level. Moreover, the short occurrence time of Door Slam noise makes the analysis more difficult. In this paper, we used the latest developed sound quality methods for analyzing Door Slam noise. And we had performed jury test for luxury vehicles. After that we had carried out correlation analysis between objective analysis and subjective test. Finally, we could suggest Door Slam noise Index by linear regression analysis."
Simple Test Method for Squeak & Rattle Evaluation of Door Trim by Using Statically Repeated Loading Robot Arm,"Recently, major car maker is specified squeak and rattle test method for subsystems or components by objective method. Generally these test method is focused on vibration environmental conditions. Especially, door trim which is located close to occupant is required additional test for squeak and rattle which is produced by occupant's interaction with door trim. To evaluate this condition, generally it can be tested by subjective method such as striking or pushing and twisting several positions of door trim. Dosing so is very time consuming and including variation results as different decisions. So, this paper suggest a new approach for evaluating squeak and rattle which is relating occupant contacting conditions to interior part, especially interior door trim. Multi-axis robot arm is examined to push automatically several points of door trim. Subjective response index for noise is checked at each point and compared with objective values which are evaluated by acceleration level of vibration. Results on subjective and objective method show that they have similar trend at each test point and is thus to adapt to new test method."
Blind Spot Monitoring by a Single Camera,"A practical and low cost Blind Spot Monitoring system is proposed. By using a single camera, the range and azimuth position of a vehicle in a blind spot are measured. The algorithm is based on the proposed RWA (Range Window Algorithm). The camera is installed on the door mirror and monitoring the side and rear of the host vehicle. The algorithm processes the image and identifies range and azimuth angle of the vehicle in the adjacent lane. This algorithm is applied to real situations. The 388 images including several kinds of vehicles are analyzed. The detection rate is 86% and the range accuracy is 1.6[m]. The maximum detection range is about 30[m]."
Optimization of MAC Side Window Demister Outlet by Parametric Modelling through DFSS Approach,"In recent years clearing the mist on side windows is one of the main criterions for all OEMs for providing comfort level to the person while driving. Visibility through the side windows will be poor when the mist is not cleared to the desired level. “Windows fog up excessively/don't clear quickly” is one of the JD Power question to assess the customer satisfaction related to HVAC performance. In a Mobile Air Conditioning System, HVAC demister duct and outlet plays an important role for removing the mist formation on vehicle side window. Normally demister duct and outlet design is evaluated by the target airflow and velocity achieved at driver and passenger side window. The methodology for optimizing the demister outlet located at side door trim has been discussed. Detailed studies are carried out for creating a parametric modeling and optimization of demister outlet design for meeting the target velocity. In this methodology, a parametric modeling of demister outlet design using the factors such as length, width, vane angles and demister outlet to window angle is created using CATIA. Design for six sigma methodologies is followed for robust optimization and arrive at the combination of appropriate design factors which influences the velocity at side windows. L18 orthogonal design array matrix has been created and flow simulations are carried out using the commercial CFD software STAR CCM+. The impacts of each design factors and levels on the side window velocity have been analyzed extensively and best combination of design factors have been found out. Parametric modelling of demister outlet significantly aids in reducing the manual design time for simulation by 50% and DFSS approach helps in finding out the optimized design factors of demist outlet during the design phase of new programs."
A New Method of Characterizing Wind Noise Sources and Body Response for a Detailed Analysis of the Noise Transmission Mechanism,"Interior noise caused by exterior air flow, or wind noise, is one of the noise-and-vibration phenomena for which a systematic simulation method has been desired for enabling their prediction. One of the main difficulties in simulating wind noise is that, unlike most other noises from the engine or road input, wind noise has not one but two different types of sources, namely, convective and acoustic ones. Therefore, in order to synthesize the interior sound pressure level (SPL), the body sensitivities (interior SPL/outer source level) for both types of sources have to be considered. In particular, sensitivity to the convective input has not been well understood, and hence it has not been determined. Moreover, the high-frequency nature of wind noise (e.g., the main energy range extends up to 4000 Hz) has limited the effective application of CAE for determining body sensitivities, for example, from the side window glass to the occupants’ ears. This paper presents a new approach to the analysis of wind noise which has been restricted by the intrinsic nature of the noise sources (i.e., a mixture of convective and acoustic components). To cope with this dual-input complexity, a new transmission model was built to treat noise sources characterized simply as “forces” impinging upon the body surfaces regardless of the type of source and noise transfer functions (NTFs) employed as body sensitivities to the forces. This model enables a quantitative synthesis of interior noise and also a contribution analysis of the sources and/or body sensitivities with high accuracy."
Vibration Design of Experiments with Varying Factors on a Panel-Beam System,"Both vehicle roof systems and vehicle door systems typically have viscoelastic material between the beams and the outer panel. These materials have the propensity to affect the vibration decay time and the vibration level of the panel with their damping and stiffening properties. Decay time relates to how pleasant a vehicle door sounds upon closing, and vibration level relates to how loud a roof boom noise may be perceived to be by vehicle occupants. If a surrogate panel could be used to evaluate decay time and vibration level, then a design of experiments (DOE) could be used to compare the effects of different factors on the system. The purpose of this paper is to show the effect of varying test factors on decay time and vibration level on a panel-beam system with viscoelastic material applied. The results were calculated using DOE software, and they were used to construct optimized systems for validation testing. The test regimen used a modal hammer to excite the system and a piezoelectric accelerometer to measure the response. The input force measured with the modal hammer was used to normalize the structural responses. The conclusions of this work are presented and examined."
Interior Noise Reduction in a Passenger Vehicle through Mode Modulation of Backdoor,"Inside cabin of a passenger car, low frequency booming noise still presents a major hurdle for NVH engineers to fine tune a vehicle. Low frequency booming noise is presently taken care with addition of mass damper and large reinforcements. These conventional countermeasures add weight to the vehicle as well as increase the overall production cost. The study presented in this paper proposes a countermeasure model that not only reduces the booming noise but also avoids any weight and cost addition. It has been focused for low frequency booming noise around 30 ∼ 40 Hz. Within the range mentioned, one of the major reasons for booming noise in hatchback models is the bending resonance of backdoor. By modifying the mode of the backdoor in such a manner that it cancels the effect of bending on the vehicle acoustic cavity, improvement can be achieved in terms of sound pressure level at the driver’s right ear location (DREL). Present study utilizes an innovative approach to change the bending mode of the backdoor into twist mode. This has been achieved by offsetting the latch and striker assembly from conventional center location to either side on the transverse axis. The study has been done on a correlated full vehicle trimmed model of a subject vehicle. Maximum improvement of 6 dB(A) has been achieved through the proposed countermeasure. The countermeasure has been applied horizontally to all hatchback models having a backdoor that opens downside-up. The effect of the countermeasure was found to be substantial."
Novel Aircraft Ground Operation Concepts Based on Clustering of Interfaces,"The projected uptick in world passenger traffic challenges the involved stakeholders to optimise the current aviation system and to find new solutions being able to cope with this trend. Since especially large hub airports are congested, operate at their capacity limit and further extensions are difficult to realise. Delays due to late arrival of aircraft or less predictable ground operation processes disrupt the airport operations in a serious way. Various concepts improving the current turnaround processes have been presented thus far, whereby radical aircraft design changes have little chances for realisation in the short term. By maintaining the established overall aircraft configuration, the concepts promote higher probability to become commercially available for aircraft manufactures and operators. Based on a clustering of aircraft interfaces, such as doors and service panels, for state-of-the-art passenger aircraft, concepts targeting to reduce the required resources and time are presented. First studies show that relocating and installing wider passenger doors allow shortening the passenger egress and ingress process by up to 55% compared to current short-to-medium haul aircraft. From a cabin layout point of view, a merger of two galleys and spatial separation from the cabin entrance area would enable a parallelisation of de-/boarding and catering operations which save up time to 20%. The implementation of these single improvements radically shortens the average turnaround time by almost 55% for a full-service carrier and 32% for a low-cost carrier scenario. Furthermore, weight penalties due to additional installed aircraft systems are translated into block fuel deltas of around +0.3% on a 500 nm (926 km) trip. The presented concepts promote a large improvement potential to turnaround time with minor-to-moderate aircraft modifications as well as a higher level of process robustness and thus have the potential to increase airline revenues."
Design Methodology of an Automotive HVAC Mechanism and Its Numerical Validation Using Multibody Simulation,"In order to ensure a comfortable space inside the cabin, it is very essential to design an efficient heating ventilating and air-conditioning (HVAC) system which can deliver uniform temperature distribution at the exit. There are several factors which impact on uniformity of temperature distribution. Airflow distribution is one of the key parameter in deciding the effectiveness of temperature distribution. Kinematics links and linkage system typically termed as ‘mechanism’ is one of the critical sub-systems which greatly affects the airflow distribution. It is not the temperature uniformity but also the HVAC temperature linearity also depends on airflow distribution. Hence the design of mechanism is incomparably of paramount importance to achieve the desired level of airflow distribution at HVAC exit. The present paper describes the design methodology of automotive HVAC mechanism system. To this context various parameters which contribute in designing the mechanism were studied and then a layout was made in CAD. Further the design was evaluated numerically using the MBD (multibody dynamics) of Hypermesh software from which torque to drive the mechanism was predicted as well the reaction force at doors. The design was fine tuned to reduce the operating effort. Finally the predicted operating effort was validated by making the physical sample and it is found that numerical results are in good agreement with that of experimental results. So adoption of such methodology in the early stage of design ensures better and better design of automotive HVAC system."
Closures weatherstrips with variable cross sections,"Closures systems performance is a trade-off between NVH (Noise, Vibration and Harshness) and DCE (Door Closing Efforts) requirements. Dynamic sealing performance and sheet metal rigidity are the key contributors for a stable system. The seals actuate like a spring on the system. Higher seal load is good for NVH performance, adding more dumping to the system, but it will negatively affect DCE, as it will demand additional energy to close the system. Nominal seal load must be defined to achieve a balance between these attributes. This study is about dynamic sealing profiles with variable seal load, which provides tunable solutions to address the trade-off between NVH and DCE on the side doors or rear closures. Dynamic sealing weatherstrips are made of sponge EPDM extruded profiles with a specified load, defined by its CLD (Compression Load Deflection), which is given by the cross section design. While standard extrusion process produces a single cross section profile, a new extrusion technology provides the possibility of varying the profile cross section along the extrusion, thus the possibility to have different CLDs along the length of door perimeter. This technology can assist on the issues that demand quick solutions on vibrations and load relieves, providing good results for these critical attributes. Timing and costs are very attractive as well on the small car segments."
Aeroacoustics of Heavy Duty Truck Side Mirrors - An Experimental Study,"Side mirrors are a known source of aerodynamically generated noise in vehicles. In this work we focus on mirrors for heavy duty trucks, they are large, often not designed with main focus on aero-acoustics and are located in a cumbersome position on the up-right A-pillar of European trucks. First the test method itself is discussed. To allow fast and cost effective design loops a bespoke vehicle, where the powertrain is separated from the cab, is developed. This vehicle can be run on a standard test track. While running the tests the wind speed is monitored, any variations are then compensated for in the post processing allowing averaging over longer time periods. For the mirror tests the door of the vehicle was especially trimmed to reduce other transmission paths into the cab than the side window. Additionally other possible aeroacoustic sources were reduced as much as practically possible. The generated wind noise was monitored with surface microphones both on the mirror (in the wake) and on the window. Additionally arrays of microphones were placed inside the cab and also accelerometers on the window. First the method is evaluated using a dummy mirror that basically is a Strouhal tone generator. Then actual mirrors were tested. It is seen that although the hydrodynamic turbulence noise dominates at the surface microphones on the window, the noise that actually is seen inside the cab is the acoustic sources generated by the separation around the mirror and A-pillar and convected at the speed of sound to the window."
Localization of BSR Noise Source Using the Improved 3D Intensity Method,"A three-dimensional (3D) sound intensity probe is used to identify the trim components generating buzz, squeak, and rattle (BSR) noise in a vehicle interior. The 3D intensity probe has the advantages of compact overall size, small number of microphones, and low-frequency detection capability. Although the 3D sound intensimetry has been not popularly applied in practical problems due to various bias errors, a new error compensation method is adopted in this work, substantially improving the estimate’s precision. Linearization of the phase function of the cross-spectral density function between a set of two microphones is used to calculate the intensity avoiding spectral bias error, and an error map for spatial angles is used to compensate for the difference in directivity index around the microphone array. An intensity probe with an even microphone spacing of 30 mm in tetrahedral arrangement is used for the source localization. The interior space is usually a nearly dead room in terms of absorption, but the reverberation effect cannot be neglected due to the small space. Experiments are conducted by using the artificially generated and edited signals pertaining the typical characteristics of each BSR noise. Various source positions are selected, such as the instrument panel, door hinge, seat, etc., and the sound levels of the source and background are changed. The estimated bearing angles of the noise sources are analyzed on a two-dimensional plot. It is found that the localization error is generally less than 6°, which demonstrates the full possibility of using this improved 3D intensity technique for the localization of BSR noise sources in the real time."
NVH Analysis of Lightweight Steel Components in Full Vehicle,"With tighter environmental regulations, as well as political and public opinion pressure, the reduction of automotive polluting gas emissions is subject to intense debates and interests. Before a potential transition to full electrical vehicles as the long term solution, the reduction of mass remains of prime importance to permit direct reduction of emissions in internal combustion engine (ICE) vehicles. In addition to the challenges of structural integrity and safety issues, the acoustical and vibration performance of vehicles can be greatly influenced by mass reduction. This article presents a case study of lightweight design of an automotive door with a high strength steel thin gauge outer panel. An experimental comparison between a reference and a lightweight door was conducted in a complete vehicle, allowing assessing the potential effect of the mass reduction on the acoustic and vibrational performances. Several conditions were assessed: rolling on different surfaces, transient events such as heavy vehicle crossing and door closing events. The comparison method included the determination of main transfer paths on the full vehicle. The study indicated that the different acoustic and vibration performances of the vehicle were preserved."
Full Vehicle NVH CAE Methodology Development to Address Tailgate Rattling on a Future Tata SUV,"In recent years, car manufacturers have been working intensively on new ways to improve the quality of interior trims. Elimination of squeak and rattle has become one of the main concerns for car manufacturers lately, given the significance of these incidences in customers' perception of overall quality. Traditionally, rattle problems are found and fixed with physical tests at the late design stage, mainly due to lack of up-front CAE simulation prediction methodology and tools availability. This article presents a finite element based methodology for the improvement of rattle performance of a vehicle tailgate. In this study, appropriate finite element (FE) modeling technique was introduced to accurately predict occurrence of tailgate rattle. Simulation process using commercial software “Nastran” employing modal and forced frequency response analyses was illustrated. Design modifications were incorporated for performance improvement of rattling on present and future SUVs. The simulation methodology and results were validated with experiments on an existing SUV model, with BSR inputs at left rear tire and acceleration responses measured on body and tailgate. Usefulness of this study to predict tailgate rattling in future SUVs was underlined with an example."
A Test Methodology for Vehicle Wind Noise Reduction and Acoustic Quality Improvement,"Aeroacoustics of vehicles is becoming an important design criterion as it directly affects passenger’s comfort. The wind noise at highway speeds (>80 KMPH) is a critical quality concern under normal and crosswind conditions and dominant factor in assessing acoustic comfort of the vehicle. Wind noise is caused by the vortex air flow around a vehicle body and air leakage through the sealing gaps of attached parts. This majorly contributes to high frequency noise (>250 Hz). Accurate identification and control of noise sources and leakage paths result in improved acoustic comfort of the vehicle. In this paper, aero-acoustic quality characteristics of validation prototype vehicle are studied. The major wind noise sources and leakage paths in the vehicle are identified through in-house blower set up in the semi anechoic room. The overall wind noise level and articulation index of vehicle at various speeds are determined through on- road measurements. The improvement in the vehicle articulation index (AI) by 14% and reduction in noise level by 4 dB (A) are achieved through design modification of seals, door structure and trim parts."
Design of Automotive Structures Using Multi-Model Optimization,"The use of structural optimization in the design of automotive structures is increasingly common. However, it is often challenging to apply these methods simultaneously for different requirements or model configurations. Multi-model optimization (MMO) aims to simplify the iterative design process associated with optimizing multiple parts or configurations with common design variables especially when conflicting requirements exist. In this paper, the use of MMO is demonstrated to evaluate the feasibility of an automotive door concept using an alternative material."
"Vibration Fatigue for Chassis-Mounted, Cantilevered Components","Vehicle chassis mounted cantilevered components should meet two critical design targets: 1) NVH criterion to avoid resonance with road noise and engine vibration and 2) satisfied durability performance to avoid any incident in structure failure and dysfunction. Generally, two types of testing are performed to validate chassis mounted cantilevered component in the design process: shaker table testing and vehicle proving ground testing. Shaker table testing is a powered vibration endurance test performed with load input summarized from real proving ground data and accurate enough to replicate the physical test. The proving ground test is typically performed at critical milestones with full vehicles. Most tests are simplified lab testing to save cost and effort. CAE procedures that virtually replicate these lab tests is even more helpful in the design verification stages. A method for defining load input, Power Spectral Density or Sine Sweep, to predict the fatigue life of chassis component will be discussed. The CAE process for this topic, with an air suspension compressor support bracket as an example, is presented for vibration stress and fatigue as well as a process to predict and correlate a vibration shaker table key life test."
Simulation and Optimization Driven Design Process for S&R Problematic - PSA Peugeot Citroën Application for Interior Assembly,"NVH (Noise Vibration & Harshness) is one of the main focus areas during the development of products such as passenger cars or trucks. Physical test methods have traditionally been used to assess NVH, but the necessity for reducing cost and creating a robust solution early in the design process has driven the increased usage of simulation tools. Development of well-defined methods and tools for NVH analysis allows today’s OEMs to have a virtual engineering based development cycle from concept to test. However, a subset of NVH problems including squeak and rattle (S&R) have not been generally focused upon. In a vehicle, S&R is a recurring problem for interior plastic parts such as an instrument panel or door trim. Since 2012, Altair has been developing S&R Director (SnRD), which is a solution that identifies and combats S&R issues by embedding the Evaluation-Line (E-Line) methodology [1] [2]. This methodology is based on industry best practices, as described in the paper SAE 2012-01-1553. This simulation based approach consist of predicting the risk of S&R for trim parts, identifying the root causes, and proposing solutions to the projects via robustness analysis and optimization. This type of simulation integrates design & manufacturing data (GD&T) as well as advanced material testing data."
Cabin-Ambient Air Exchanges and Their Relation to In-Vehicle CO 2 Concentration,"It is common for users of commuting passenger cars in Thailand to use the vehicle’s HVAC (Heating, Ventilating and Air Conditioning) system predominantly in recirculation (REC) mode. This minimizes the compressor work, thereby saving fuel, and reduces dust and odor infiltration into the vehicle cabin. The car windows are rarely opened for ventilation purposes, except for exchanges at service stations such as garage entrances and tollway booths. As such, there are few opportunities for fresh air to enter the cabin with the consequent accumulation of CO2 in vehicle cabins due to occupants’ exhalations being well documented. Field experiments conducted showed that the in-vehicle CO2 concentrations could reach up to 15 times that of the ambient concentration level during typical city commutes. Preliminary experiments were also conducted to quantify the air exchanges between the cabin and the ambient when the doors are opened for occupant egression. The results indicated that the amount of air exchange depends on the prevailing wind speed and direction, the number of doors opened, and the duration of the door opening."
Prediction of Mirror Induced Wind Noise Using CFD-FEM Approach,"Wind noise is becoming important for automotive development due to significant reductions in road and engine noise. This aerodynamic noise is dominant at highway speeds and contributes towards higher frequency noise (>250Hz). In automotive industry accurate prediction and control of noise sources results in improved customer satisfaction. The aerodynamic noise prediction and vehicle component design optimization is generally executed through very expensive wind tunnel testing. Even with the recent advances in the computational power, predicting the flow induced noise sources is still a challenging and computationally expensive problem. A typical case of fluid-solid interaction at higher speeds results into broadband noise and it is inherently an unsteady phenomenon. To capture such a broad range of frequency, Detached Eddy Simulation (DES) has been proven to be the most practical and fairly accurate technique as sighted in literature. Present work talks about the application of Detached Eddy Simulation (DES), as a computationally faster and cheaper method for predicting the flow and sound generation. In the present case a mirror mounted on SUV has been investigated numerically using Finite Volume Code, FLUENT in flow domain and FEM methodology with appropriate aero acoustic analogies in structural domain. In this study, the effect of mirror configuration on the vehicle interior noise has been presented. The analysis has been carried out on baseline mirror, new mirror (door mounted) and no mirror cases. The average sound pressure level inside the vehicle observed to be reduced by 17% with door mounted mirror compared to baseline mirror case."
"Stiffness Simulation Techniques and Test Correlations in Automotive Interior Cockpit Systems (IP, Door Trim and Floor Console Assembly)","An automotive cockpit module is a complex assembly, which consists of components and sub-systems. The critical systems in the cockpit module are the instrument panel (IP), the floor console, and door trim assemblies, which consist of many plastic trims. Stiffness is one of the most important parameters for the plastic trims' design, and it should be optimum to meet all the three functional requirements of safety, vibration and durability. This paper presents how the CAE application and various other techniques are used efficiently to predict the stiffness, and the strength of automotive cockpit systems, which will reduce the product development cycle time and cost. The implicit solver is used for the most of the stiffness analysis, and the explicit techniques are used in highly non-linear situations. This paper also shows the correlations of the CAE results and the physical test results, which will give more confidence in product design and reduce the cost of prototype testing."
A Case Study for Automotive Door Closing Effort Uncertainty Analysis based on Monte Carlo Simulation Method,"Quality in the automotive industry means development and manufacturing of vehicles whose specifications meet customer requirements. Among many other quality issues, door closing effort is a vehicle characteristic that strongly affects the customer first opinion about vehicle design. The door closing effort is affected by uncertainties in materials and manufacturing processes. The present paper presents a reliability-based method to evaluate the uncertainties associated with door closing effort due to manufacturing processes. A formulation is proposed to calculate that energy based on three components: energy used to compress air into the vehicle, energy used to compress the sealing and energy used to lock the door. In order to quantify the probability that the door closing effort is greater than a target value, reliability analysis concepts are used based on the uncertainties associated to latch position. The Monte Carlo simulation is used to define door closing effort variability due to variation of the side door latch position. That analysis allows defining maximum allowable latch and striker position variability in order to keep door closing effort below a target value. The latch position uncertainty is modeled by a probability distribution defined based on data collected from the assembly process. The probability of having a door closing effort magnitude lower than a target value is then calculated. Simulated distribution is compared to experimentally door effort analysis showing very good agreement between them. The simulation based model is used to evaluate the feasibility of manufacturing processes changes to reduce door closing effort."
Simulating Human Body Touch Automotive Tests Using Industrial Robot & Intelligent Grippers Equipped With Sensors,"All Automotive companies conduct various performance and Endurance tests on automotive bodies, doors by using Pneumatic Actuators. These Actuators can only give linear or rotary motion. Therefore these can neither simulate the complex motion of Human arm nor can they simulate the Force and pressure induced by the Human palm or Human back on the body domain parts. Each test need to have different test setup. This paper discusses how a system of industrial Robot coupled with intelligent Gripper with sensors and feedback signal to robot can be used to simulate the effect of Human touch during testing."
Motor Control in Auxiliary Drive Systems How to Choose the Best Fitting Electronic Solution,"In modern vehicles, the number of small electrical drive systems is still increasing continuously for blowers, fans and pumps as well as for window lifts, sunroofs and doors. Requirements and operating conditions for such systems varies, hence there are many different solutions available for controlling such motors. In most applications, simple, low-cost DC motors are used. For higher requirements regarding operating time and in stop-start capable systems, the focus turns to highly efficient and durable brushless DC motors with electronic commutation. This paper compares various electronic control concepts from a semiconductor vendor point of view. These concepts include discrete control using relays or MOSFETs. Furthermore integrated motor drivers are discussed, including system-on-chip solutions for specific applications, e.g. specific ICs for window lift motors with LIN interface. In most cases, system suppliers have the choice between several electronic partitioning concepts, based on specific technical and economic conditions up to given specific preferences of the supplier."
Supporting Hinge Arrangement for Heavy Weight Side Opening Tailgate,"The tailgate is the fifth or the rearmost door of an SUV (Sports Utility Vehicle)[1]. It can be side opening or top opening. It is attached to the BIW (Body In White) with two hinge arrangement. The hinges are designed to take the cantilever load of a normal side opening tailgate along with the passenger ingress/egress load. This means that apart from the doors own weight, the hinges have to take the extra load which a passenger exerts on it by resting his/her forehand on the handle. The hinges are designed to take these loads and under normal circumstances, they do not fail for acceptable number of cycles of opening and closing of the tailgate. But in case of an armored vehicle side opening tailgate, it is quite a challenge for the normal hinges to take the heavy load of the tailgate along with passenger ingress / egress load. The normal hinges (Refer figure-1) obviously fail under such heavy loads either in their design or material configuration. To take this extra load, designers had to think of an innovative arrangement/concept that was simple yet convenient from retrofitting point of view on an armored vehicle configuration. Such an innovation was thought off, designed and implemented successfully on first prototype of the armored SUV. Figure 1 Figure showing the view of a portion of a tailgate from outside of the SUV. Normal hinges are visible as shown in yellow color. Also visible is the aperture plate of the arrangement in blue. (BIW not shown.)"
An Improved Methodology for Calculation of the Inertial Resistance of Automotive Latching Systems,"This paper outlines an improved methodology to perform calculations to verify the compliance of automotive door latch systems to minimum legal requirements as well as to perform additional due diligence calculations necessary to comprehend special cases such as roll over crashes and locally high inertial loadings. This methodology builds on the calculation method recommended by SAE J839 and provides a robust and clear approach for application of this method to cable release systems, which were not prevalent at the time J839 was originally drafted. This method is useful in and of itself but its utility is further increased by the application of the method to a Computer Aided Design (CAD) template (in this case for Catia V5), that allows some automation of the calculation process for a given latch type. This will result in a savings of time, fewer errors and allows for an iterative concurrent analysis during the design process."
The Topology Optimization Analysis on Rope-Wheel Glass Lifter,"Glass lifter is a key part of automobile door system. Guide rail is the carrier of glass lifter, and it bears various load cases when glass lifer works. Mass, stiffness and natural frequencies are the factors that influence the performance of glass lifter. In order to design a lighter and reasonable glass lifter, topology optimization methods are studied in this paper. In a rope-wheel glass lifter, design domain is determined by the mechanical structure and working conditions. Firstly, the single target continuum structure topology optimization mathematic models of guide rail are built in this paper, and analysis of multi-stiffness topology optimization are carried out accordingly in which volume fraction is set as 0.4, 0.5 and 0.6. These models are based on SIMP (Solid Isotropic Material with Penalization) theory. Secondly, multiobjective topology optimization models of guide rail are built to consider the influence of dynamic characteristics, and volume fraction is also set as 0.4, 0.5 and 0.6. These models are based on the weighted compromise programming approach. A new formula is proposed in this paper, and optimization objectives are static stiffness and dynamic frequencies, constraint is volume fraction. Comparing these two methods, single target optimization method is more efficient, whereas the structures of optimized guide rail are not reasonable due to the appearance of a large minimum density area in the middle of guide rail. The topology optimization method of considering dynamic characteristic makes the structures of the optimized guide rail more reasonable. The structural load path is clear, and more triangular structures generate which strengthen stiffness of the structure. In addition, values of optimized compliance are lower than that of the single target topology optimization and the first three order frequencies of multi-objective topology optimization are higher than that of single target. So the topology optimization method of multi-objectives makes guild rail have better rigidity and vibration characteristics, which provides a valuable basis and method for the design of guild rail."
Development of Paint-Less Black Gloss Decorative Technology for Frame Molding,"The need to add more color variations to the traditional black gloss has increased globally in recent years. The intention is for automobile manufacturers to differentiate their products in terms of appearance design. The most noticeable trend is to add embellishment around the front grill. The same trend can be seen in the areas around vehicle doors. It is most common to use a coating material to emphasize the black gloss. However, in overseas countries it is a challenge to meet the required appearance quality, and under the current circumstances CKD is imported from Japan to meet such requirements. Recently, a new film-transfer technique has been established that can express black gloss as well as any coating material by transferring the roughness of the film surface. It is achieved by crimping the PET film onto the vinyl-chloride surface after the extrusion molding is performed. Moreover, we have successfully localized this technique and reduced the manufacturing cost. Thus, the development process will be described."
Closure Slam CAE Method Investigation for Automobiles,"In the current scenario, the major thrust is to simulate the customer usage pattern and lab test using virtual simulation methods. Going ahead, prime importance will be to reduce the number of soft tool prototype for all tests which can be predicted in CAE. Automotive door slam test is significantly complex in terms of prediction through simulation. Current work focuses on simulating the slam event and deriving load histories at different mounting locations through dynamic analysis using LSDyna. These extracted load histories are applied to trimmed door Nastran model and modal transient analysis is performed to find the transient stress history. This approach has a significant advantage of less computation time and stress-convergence with Nastran for performing multiple design iterations compared to LSDyna. Good failure correlation is achieved with the test using this approach. Using these load histories, design improvements are evaluated and robustness of the approach is validated. An attempt is made to extract load histories using virtual mule in LSDyna. So, at an early stage in a project, using the only hinge and latch CAD location with closure mass, inertia and center of gravity, the load histories can be extracted and design improvement can be evaluated. Detailed analysis of predicting over-slam through simulation and effect of the position of glass on strain at different locations is highlighted."
A Multi-Function Automotive MM-Wave Radar Design,"A 24GHz multi-function assist system has been developed for advanced automotive radar, which includes different applications in Blind Spot Detection (BSD), Lane Change Assist (LCA), Doors Open Warning (DOW) and Rear Cross Traffic Alert (RCTA). The multi-function radar is based on the micro-strip antenna, which has a reasonable design on main-lobe and side-lobes. According the antenna, the radar can operate in mid-range mode with a high gain and a narrow beam width, whilst performing well in short-range and wide-angle mode."
"Prediction of Aeroacoustical Interior Noise of a Car, Part-1 Prediction of Pressure Fluctuations on External Surfaces of a Car","A wall-resolving Large Eddy Simulation (LES) has been performed by using up to 40 billion grids with a minimum grid resolution of 0.1 mm for predicting the exterior hydrodynamic pressure fluctuations in the turbulent boundary layers of a test car with simplified geometry. At several sampling points on the car surface, which included a point on the side window, the door panel, and the front fender panel, the computed hydrodynamic pressure fluctuations were compared with those measured by microphones installed on the surface of the car in a wind tunnel, and effects of the grid resolution on the accuracy of the predicted frequency spectra were discussed. The power spectra of the pressure fluctuations computed with 5 billion grid LES agreed reasonably well with those measured in the wind tunnel up to around 2 kHz although they had some discrepancy with the measured ones in the low and middle frequencies. The Dynamic Smagorinsky Model (DSM) was adopted for the subgrid-scale turbulence model of LES while the resulting spatially-filtered Navier-Stokes equations of the incompressible fluid flow were solved by a Finite Element Method. In the second paper of this series of studies, the hydrodynamic pressure fluctuations computed on the car surfaces will be used as the unsteady loading for computing the panel vibration of the test car by using Finite Element Method, and finally the interior acoustical fields will be predicted by solving the Helmholtz equation for sound propagation. The contribution from the external acoustical field to the interior noise, which was not simulated by the present incompressible LES-based approach, was estimated based on the acoustic analogy, and was confirmed to be negligibly small compared with those from the hydrodynamic loading in the present case."
Construction and Kinematics of Automotive Side Door Latch Mechanisms,"Automotive side door latches are considered safety-critical systems due to both federal and automotive OEM regulations. The paper presents a kinematical study, in terms of degrees of mobility, and the basic construction for an example mechanism utilized as an automotive side door latch. This system is represented and approximated with mechanisms with articulated bars, cams and gears. Mobility calculations for such type of mechanisms involve both the determination and the investigation of all involved kinematical elements and the nature of their mobile restraints (called kinematical couples). By applying the principles and the methods described in this paper similar investigations in terms of the degree of mobility for other side door latch design applications can be investigated."
Multi-Objective RBDO for Automotive Door Quality Design,"This paper develops a multiobjective optimization methodology for automotive door quality design under uncertainty, in which the tradeoffs between two competing objectives need to be considered. Two important quality issues, door closing effort and wind noise, are of concern and the corresponding probabilities of unsatisfactory performance are considered in the optimization. Model-based reliability analysis methods are used to compute these probabilities. Both component and system-level reliability analyses need to be performed in RBDO. While a first order reliability method (FORM) is found adequate for the reliability estimation with respect to door closing effort, an adaptive Monte Carlo simulation method is found suitable for reliability analysis of the wind noise problem with multiple limit states. An efficient decoupled RBDO approach is used to solve the multiobjective optimization and the Pareto frontier is generated for decision-making. The proposed method can be applied to solve a wide variety of RBDO problems with competing objectives and reliability constraints at both component and system levels."
The Application of Magnesium Die Casting to Vehicle Closures,"During the last decade, advances in magnesium die casting technology have enabled the production of large lightweight thin walled die castings that offer new approaches for low investment body construction techniques. As a result, many OEMs have expressed an interest in magnesium door closure systems due to investment reduction opportunities, coupled with potential weight savings of up to 50%. However, for such applications, product engineers are faced with the challenge of designing for stiffness and strength in crash critical applications with a material of lower modulus and ductility compared to wrought sheet product. Concept designs for side door systems have been presented in the literature, and indicate that structural performance targets can be achieved. However, to date, series production designs feature a multitude of supplementary sheet metal reinforcements, attached to die castings, to handle structural loads. While this approach can still offer performance benefits, the additional cost of tooling and assembly has a negative impact on both overall weight and the business rationale. On the contrary, the magnesium door concepts presented in this paper describe the development of side door systems designed to replace the bulk of sheet metal stampings by a single magnesium die casting. A summary of the design, analysis, prototyping and testing stages is reported, in addition to the development of a series production door system for a 2004 model year vehicle. A review of manufacturing and test results demonstrate how magnesium can be used effectively in the manufacture of low investment, lightweight vehicle closures."
Detecting and Classifying Secondary Impacts in Door Closing Sound,"One of the primary correlates to customer annoyance with door-closing sound is peak loudness. In addition, customer annoyance also increases with the existence of secondary impacts, such as rattles. While these secondary impacts are typically not seen in the time-varying loudness trace (or other common sound quality metrics), it is often possible to visually identify the impacts in a time-frequency display of the door-closing sound. But the reduction of this display information to a single-number objective metric that agrees with subjective assessments has previously proved elusive. This paper summarizes the recent development and application of an objective metric that agrees with subjective classifications of secondary impacts in door-closing sounds."
Antenna Embedded Door Handle for Smart Key System,"It is necessary for a door handle for the smart-key system to adapt for various door handle structures. The smart-key door handle, of course, should have competitiveness. For developing the next generation of the smart-key door handle, we considered that compact sizing and easy manufacturing are the key issues. Therefore, we tried to use the wire harness as an antenna and a sensor for the smart-key system. Moreover, the bending-forming method has been developed to achieve this idea. We will introduce the development process with the commitment to improve commercial value exampling the smart-key door handle development."
A Study on the Modelling Technique for the Passenger Out-Of-Position Simulation,"There was a regulation to reduce injuries caused by airbags for OOP (Out-Of-Position) impact loading conditions. Also, many tests are needed to meet the regulation regarding design variation. And the main effect of airbag design variable has not been well known. Therefore, numerical simulation modelling method and technique were required to reduce the test numbers and recommend the airbag design guideline for OOP condition. To establish modelling procedure for OOP situations in this paper, simulation model was built and correlated with test. Also, the body block test for airbag cushion correlation, a pendulum test for opening stiffness correlation of airbag door and low risk deployment static test using 3-year-old dummy for OOP simulation correlation were performed. And, airbag door and folding condition were evaluated using full factorial DOE (Design of Experimental) technique. Finally, airbag inflator, vent hole, opening stiffness of door and friction coefficient were evaluated using orthogonal array (L9). From the DOE results, the airbag door modelling was insignificant for In-position situation whereas it was significant for OOP modelling. And the direct folded mesh shows a good correlation for OOP condition. Especially, the direct folded mesh by MOBIS folder was validated. The OOP simulation results had been mainly influenced by the inflator model and airbag door opening stiffness."
SEA Modeling of A Vehicle Door System,"The Door system is one of the major paths for vehicle interior noise under a variety of load conditions. In this paper we consider the elements of the door lower (excluding glass) in terms of noise transmission. Passenger car doors are comprised of the outer skin, door cavity, door inner sheet metal, vapor barrier, and interior trim. Statistical Energy Analysis (SEA) models must effectively describe these components in terms of their acoustic properties and capture the dominant behaviors relative to the overall door system. In addition, the models must interface seamlessly with existing vehicle level SEA models. SEA modeling techniques for the door components are discussed with door STL testing and model correlation results."
Experimental Study On the Energy Flow Analysis of Vibration of an Automobile Door,"The Energy Flow Analysis (EFA) can be effectively used to predict structural vibration in medium-to-high frequency range. In this paper, Energy Flow Finite Element Method (EFFEM) based on EFA has been used to predict the vibration of an automobile door. The predicted results for the frequency response function of the door have been compared with corresponding experimental results. In the experiment, the automobile door has been divided into several subsystems and the loss factor of each subsystem has been measured. The input mobility at a source point has been also measured. The data for the loss factors and the input mobility have been used as the input data to predict the vibration of the automobile door with EFFEM. The frequency response functions have been measured over the surface of the door. The comparison between the experimental results and the predicted results for the frequency response functions showed that EFFEM could be an effective tool to predict the structural vibration."
Low Frequency Transient CAE Analysis for Vehicle Door Closure Sound Quality,"Improvement of vehicle door closure sound quality is one of the major customer wants. It is very desirable to understand how different door elements radiate sound during a door-closing event and how to optimize a door structure to design for a specific sound target. In this paper, a CAE tool is developed based on transient FEA and BEA for the analysis of structural-borne vehicle door closure sound quality in the low frequency range (up to 300Hz). Design sensitivity analysis (DSA) are performed for investigating effects of major design variable changes on the door closing sound quality. A SUV model was studied to validate the simulation results and to demonstrate the capability of the developed CAE tool for providing design guidelines on door closing sound quality."
The Door Mounted Inflatable Curtain,"It has been shown that Inflatable Curtains have the potential to reduce head injuries in side impacts and the system has accordingly been introduced on a growing number of car models. There is also a potential benefit in rollover situations. This paper only consider performance in situations with belted occupants. To date, it has not been possible to implement an Inflatable Curtain in convertible vehicles because they lack a roof. The challenge of the Door Mounted Inflatable Curtain (DMIC) has been to overcome the lack of support and fixation possibilities offered by a roof. This paper includes a description of the DMIC and how it was integrated into the vehicle structure. The paper will also show how to create the space and support needed to utilize the internal stiffness and make it possible to fill the bag in time. The impact attenuation and ejection protection functions of the DMIC will be demonstrated."
Benefits of a New Concept Window Lift System in a Typically Constrained Door Environment,"A new design concept for a mechanism to raise and lower side dropping automotive windows provides greater in-board/ outboard compliance than conventional window lift systems. These design aspects provide advantages over current technologies. Among these advantages are: A reduction and control of vectored load inputs on the associated window lift system, having the effect of improved efficiency. A lower cost construction than conventional devices. A window lift system that is more capable of providing one-touch-up functionality meeting the anti-pinch safety criteria outlined in the Federal Motor Vehicle Safety Standard (FMVSS) 118. Drastically reduced prototyping time. This reduction is achieved by producing a general purpose product, then shaping / modifying it to approximate door geometry. The freedom of the inboard / outboard constraints makes imperfect geometry inconsequential in the evaluation of the prototypes. The method of research includes data collection of comparative systems and demonstrations of performance. a general financial analysis contrasting with conventional systems. direct comparative examples, along with anecdotal examples of actual prototype lead times. This new concept window lift regulator system, known as the Racklift™ system, due to its combination of material construction, mechanical drive geometry, low weight, consistently low power consumption, and dual axis directional flexibility, is unique in its ability to address these various functions and quality of operation. The conclusions drawn support the effects of reduced load variation as measured through velocity, current draw, noise variation, and seal wear. The conclusions also demonstrate the financial advantages and rapid prototyping of the device over conventional systems."
An Assessment of Door Openings in NASS-CDS Resulting From Combined Longitudinal Compressive and Lateral Tensile Latch Loading,"The April 1st, 2005 Global Technical Regulation (GTR) [ECE/TRANS/180/Add.1] Working Party for door locks and door retention components reviewed a combination loading static bench test for latch systems (combination test) that is capable of evaluating the strength of the latching systems and is designed to detect fork bolt detent bypass failures. In the combination test, the latch is mounted on a flat steel plate that moves horizontally. The striker is mounted on a vertically moving ram device. During the test, lateral tension of 6,650 N is applied and maintained on the coupled latch-striker system by moving the flat steel plate and then applying a longitudinal compressive force of 16,000 N by moving the striker at a constant rate. A study of field data from the National Automotive Sampling System - Crashworthiness Data System (NASS-CDS) data files for the years 2003 to 2007 was conducted to determine the prevalence of real world crashes with latch/ striker separation due to a loading environment similar to that in the combination loading test. The study also assessed whether requiring door latches to pass this combination test would translate into a significant safety benefit by reducing deaths and injuries that result when a vehicle occupant is ejected from a vehicle during a crash. Data was limited to later model year vehicles (1995+) and to cases that comprised the necessary information needed to determine impact location, direction, and severity. A total of 330 NASS-CDS cases from 2003 to 2007 were coded with at least one door latch/ striker separation. Photographic evidence and crash parameters were utilized to determine whether each door latch/ striker separation was due to loading environments represented by the combination loading test. Of the 330 cases of latch/ striker separations, 290 cases occurred in very severe crash conditions with significant vehicle damage. The latch/ striker separation in these cases was deemed to have resulted from excessive loads and vehicle deformation. Of the remaining 40 latch/ striker separation cases, only 14 had loading conditions similar to that simulated in the combination loading test for latch systems. This study also found that in recent years there has been a trend that clearly reflects a significant reduction in both the number of door latch/ striker separations and the deaths and injuries that are traceable to these failures. As a result of the small number of cases identified and the trend toward reduced numbers of door latch/ striker separations, this study found that imposing a requirement that door latches pass the combination test would prevent 1.38 to 5.37 fatalities and 0.98 to 27.20 serious injuries per year."
CAD - Based Synthesis of a Window Lifter Mechanism,"The kinematic layout is an essential part in the early development phase of an automotive door. Apart from the door opening mechanism, the main focus lies on the synthesis of the window lifter, which has a high impact on the glass shape and on window tightness properties. The main task is to find a proper window motion with respect to the space requirements and the maximum seal deflection. Boundary conditions are given by the shape of the pillars and the window which are mainly styling driven. In this contribution a method is described to compute an optimized motion allowing for all such restrictions. The applied method is based on a CAD platform and combines simulation with parametric-associative design. This leads to a high level of flexibility and simple handling. The presented approach is an example of an upfront design analysis significantly supporting the door development process."
Pressure Sensor Simulation Capability for Side Impact Sensing Calibration,"There is a growing interest in using pressure sensors to sense side impacts, where the pressure change inside the door cavity is monitored and used to discriminate trigger and non-trigger incidents. In this paper, a pressure sensor simulation capability for side impact sensing calibration is presented. The ability to use simulations for side impact sensing calibration early in the vehicle program development process could reduce vehicle development cost and time. It could also help in evaluating sensor locations by studying the effects of targeted impact points and contents in the door cavity. There are two modeling methods available in LS-DYNA for predicting pressure change inside a cavity, namely airbag method and fluid structure interaction method. A suite of side impact calibration events of a study vehicle were simulated using these two methods. The simulated door cavity pressure time histories were then extracted to calibrate the side sensing system of the study vehicle. The calibration result shows that both the airbag method and the fluid structure interaction method are capable of predicting the pressure change inside the door cavity for side impact sensing calibration purposes, albeit the former requires much less computer run time than the latter."
A Simple Method to Calculate Vehicle Heat Load,"The first challenge to properly size a vehicle A/C system is to define the vehicle air conditioning heat load requirement. Within automotive industry, a model to accurately define vehicle heat load is still under development. In this study, a simple method to calculate vehicle heat load is developed. The cooling load temperature differential (CLTD) method[1] is used to calculate the heat gain of a sunlit roof and wall (door). This is done in one step by using ASHRAE data. The calculation presented here takes into account the geometrical configuration of the vehicle compartment including glazing surfaces (shading), windshield and roof angle, and vehicle orientation, Special attention is given to the calculation of direct and diffuse incidence solar radiation through the windshield and skylight glass. The vertical glass' solar heat gain is evaluated by using ASHRAE[1] data. The U value method is used to calculate heat transfer between the outside and inside cabin. Heat gains from infiltration, occupant, and HVAC unit blower motors are considered in the cooling load calculation. The method accuracy was validated using wind tunnel tests. The results showed the predicted cooling load is very close to the tested value, and the deviation between calculated and tested heat loads is smaller with fresh air mode than that with recirculation mode."
Control of Airborne Road Noise Using Sealers,"Noise generated during tire/road interaction has significant impact on the acoustic comfort of a vehicle. One of the most common approaches to attenuate road noise levels consists on the addition of mass treatments to the vehicle panels. However, the acoustic performance of sealing elements is also relevant and has an important contribution to the noise transmission into the vehicle interior. In this paper the correct balance between the mass added to treat vehicle panels and sealing content is investigated. The procedure to quantify the critical road noise transmission paths consists of recording interior noise levels as applied treatment is removed from potential weak areas, such as wheelhouses, floor, doors and body pillars. It is observed that the noise propagation through body pillars has a direct influence on road noise levels. In this case, the use of acoustic sealers placed in the body pillar sections can reduce noise transmission particularly at high frequencies leading to the achievement of desired vehicle acoustic comfort levels."
Objective chime sound quality evaluation,"Customer perception of vehicle quality and safety is based on many factors. One important factor is the customers impression of the sounds produced by body and interior components such as doors, windows, seats, safety belts, windshield wipers, and other similar items like sounds generated automatically for safety and warning purposes. These sounds are typically harmonic or constant, and the relative level of perception, duration, multiplicity, and degree of concurrence of these sounds are elements that the customer will retain in an overall quality impression. Chime sounds are important to the customer in order to alert that something is not accomplished in a right way or for safe purposes. The chimes can be characterized by: sound level perception, frequency of the signal, shape of the signal, duration of the “beep” and the silence duration. The purpose of this work is to use psychoacoustic parameters and time-frequency tools in order to quantify the sound quality perception of chime sounds like key off headlamp on and the unclosed door with gear out of parking mode."
A Novel Test Rig for the Aerodynamic Development of a Door Mirror,"Door mirrors have a small but measurable contribution to the overall aerodynamic drag of a road vehicle. Typically for passenger cars and SUVs this is in the range 2.5–5%. It can be difficult to refine the shape of door mirrors as the improvements are, sometimes, too small to measure with any accuracy. A test rig has been developed which allows a full size door mirror to be tested in a model wind tunnel facility, which has better balance resolution, where the mirror is mounted to a partial vehicle body. This also results in a faster and cheaper method to develop shapes for door mirrors. The rig is described and the initial correlation tests presented. The limitations of the rig and some further applications are discussed."
Design of Dual Sliding Door for a Small-size Car and Its Validation Using CAE Tools,"Sliding doors are usually employed on the rear side of minivans and some large vehicles for easy egress and ingress. Furthermore, dual sliding doors are frequently observed in various concept models. This paper describes design of a dual sliding door for a small-size car. A new sliding mechanism with two sliding contact points is proposed with the B-pillar incorporated in the door structure made of high strength steel. Two sliding tracks are located in the door and the rocker panel. The door linkages first swivel and then slide with the help of the rollers in the tracks to open the door. The sliding mechanism and the door structure were validated using CAE tools such as HyperMesh, MSC/NASTRAN [2] and LS-DYNA[3]. This validation process was divided into three parts: (1) Dynamic Stiffness Analysis or the normal mode analysis to understand the natural frequency response of the door. (2) Static Stiffness Analysis or the Door Sag analysis was conducted to see the structural strength of the door in static loading. Finally, (3) Quasi-static side intrusion analysis was performed to see the resistance of the door structure against an intruding pole. The analysis results showed that the door structure achieved the desired structural performance requirements."
Automotive Side Glazing for Primary and Secondary Occupant Retention,"The occupant retention performance of laminated and tempered side glazing during rollover collisions is analyzed. A brief history of automotive glazing is given, including a discussion of current technology. A summary of glazing failure mechanisms is provided, along with the results of impact and quasi-static pushout testing of undamaged commercial and prototype door windows. The investigation shows that supported laminated side glazing gives performance comparable to windshield glazing and can effect both primary and secondary containment of occupants. Results of documented unplanned rollover collisions and staged rollover tests are presented in support of the conclusions drawn."
Touch Feel and Appearance Characteristics of Automotive Door Armrest Materials,"This paper presents results of a five phase study conducted to evaluate touch feel and appearance of door armrest materials. Seven different production door armrests with different material characteristics such as softness, smoothness, compressibility, texture, etc. were evaluated. In the first phase, the subjects seated in a vehicle buck in their preferred seating position with the armrests adjusted at their preferred heights, provided ratings on a number of touch feel and appearance of the door armrest materials using 5-point semantic differential scales. In the second phase, the armrests were presented to each subject in all possible pairs and they were asked to select preferred armrest material in each pair. In the third phase, pressures in the armrest contact area were measured in three armrest usage postures, namely: i) lower arm supported on the armrest (not holding the steering wheel), ii) elbow resting on the armrest while grasping the steering wheel, and iii) the subject attempting to reposition in the seat while pushing his/her elbow against the armrest (maximum possible pressure). Pressure measurements (peak, average and contact area) were made for 12 subjects using XSENSOR pressure mapping digital mat. The fourth phase involved evaluation of all the touch characteristics in the dark to eliminate any visual influence. And finally, in the fifth phase, the subjects were asked to rank order important characteristics of the armrest materials. Some results of the studies are: a) The 95% confidence intervals of 5-point ratings discriminated different armrests on each characteristic defined by adjective pairs such as Smooth/Rough, Compressive/Non-Compressive, Plain/Textured, Fine/Coarse, etc. b) Correlation analyses revealed a number of relationships between the variables (e.g. Soft/Hard ratings were highly correlated with Compressive/Non-Compressive ratings, Cheap/Expensive ratings were correlated to Fake/Genuine, and Pleasing/Non-Pleasing ratings; but Texture/Plain were uncorrelated with Cheap/Expensive or Fake/Genuine ratings). c) The pressure measurements data showed: i) Under normal forearm resting posture the average and peak pressures ranged between 3 to 10 psi and 4 to 25 psi, respectively. ii) With the elbow resting on the armrest while holding on the steering wheel, the average and peak pressures ranged between 4 to 19 psi and 5 to 40 psi, respectively. iii) While repositioning in the seat, the average and peak pressures ranged between 5 to 17 psi and 10 to 40 psi, respectively. d) Evaluations of touch feel conducted in the dark, differed from those from those conducted using both touch and visual sensory cues."
Measuring the Pitch of Door Closing Sounds - The Sound Quality Issue of Door “Thump”,"This paper discusses a partially completed project that was begun shortly before an unexpected retirement opportunity appeared that limits the possibilities for follow-up work. The project was to investigate the pitch of door closing “thump.” The impetus for the investigation was a paper by Gardner and Magnasco. Their paper described an instantaneous frequency decomposition method that they used in the study of bird song and human speech. Bird song or speech may not seem to be closely linked to measuring door closing thump but the speed with which the frequencies in door closing sounds change is not that different from the speed of frequency change in bird song or speech. Two questions that immediately arise are can Gardner and Magnasco's technique resolve the low frequency components that occur in door closing sounds and, if so, do they relate to human perception of thump? This paper can only present a brief look at the encouraging results from preliminary work to answer the first question. Further work is needed to completely answer the two questions and either confirm or reject the technique."
Optimization of Mirror Angle for Front Window Buffeting and Wind Noise Using Experimental Methods,"Door mirrors have a major impact on wind noise observed at the driver's ear. The mirror distance and angle with respect to the front side glass will influence the front window buffeting characteristics of the vehicle as well. Optimizing the mirror angle to minimize or eliminate buffeting while maintaining acceptable wind noise performance can provide additional customer satisfaction. Changes to the mirror angle were investigated experimentally for both wind noise and buffeting effects. Experimental vehicle interior noise and buffeting data was taken at multiple yaw angles and wind speeds using a full scale aero acoustic wind tunnel. In addition, experimental wind noise attributes for the different mirror angles was also used to determine the optimal angle. The resulting angle measurement will be used as a best practice mirror angle for optimal wind noise and front window buffeting performance on future vehicle programs."
Capacitive Sensing in an Automotive Environment,"Capacitance sensing in motor vehicles allows for protection in power windows, sunroofs, liftgates and sliding doors. It also provides greater design freedom of operator interfaces that include switch entry and fingerprint sensing. Fingerprint sensing adds new levels of security for the access and starting of a vehicle thus allowing for the elimination of keys. This paper describes the design and operation of various systems that could employ capacitive sensing technology including keyless entry, operator controls, and safety related sensing. Also discussed are vehicle installation, safety enhancement, and ergonomic benefits."
Rapid Prototyping Applied to Parts Used in Static Tests of Racks for Packing and Transporting Automobile Parts,"This work was motivated by the specific needs of a materials flow and packing planning sector (PFME), within a manufacturing engineering department of a vehicle assembly company in Brazil. In this sector, there is a growing need to obtain prototype parts in the shortest time and at the lowest cost possible in order to carry out static prototype tests of the special packing and transportation racks used in this company, since these racks need to be ready to assist the preparation phase of the series production of the vehicle. The objective of this work is to survey the academic theory and the existing literature in order to find an application proposal of rapid prototyping (RP) techniques to make the parts used in the rack tests, thus reducing time and acquisition costs. For that purpose, some limiting conditions were considered: first, the application of the RP technique is limited to the external parts of the vehicle, such as doors, front and back hoods, and fenders; second, the consulted suppliers should be available in the domestic market. Finally, a proposal of work systematics for the assembly company is presented."
Design of Door Latching and Locking Systems for Crashworthiness,"Several sub-systems in a vehicle contribute to vehicle crashworthiness. One such system is the door latch and locking system. Correct functioning of this system is critical for facilitating occupant evacuation and preventing occupant ejection during crashes. Special care needs to be taken during vehicle safety development to achieve the desired intent. In crashes, it is observed that door opening or locking mainly occurs on account of inertial loads and deformation of the door structure. This paper studies the possible failure modes and their causes. Some likely solutions have also been discussed with a case study."
A Case Study About Side Door Closing Sound Quality,Side Door Closing Sound Quality is one of the first impressions a potential customer has about a vehicle. It can enhance an impression of robust and high quality vehicle. This paper is a study of Side Door Closing Sound of a specific vehicle model. The main objective is to understand how Door Closing Sound Quality varies over several vehicles samples and how to improve the design and/or production process in order to achieve better Sound Quality. Two vehicles (same model) with distinct performance have been chosen among several samples. Both have been evaluated and the physical differences are weighted to realize what really matter for Door Closing Sound Quality.
Investing Factors Affecting Door Slam Noise of SUV and Improved Performance by DFSS Approach,"Recent development in automobile industries has seen increased customer attention for good door slamming noise. One of the constituent which plays major role in building brand image of vehicle in terms of NVH performance is door slam noise quality. Hence it is very desirable to understand how different door elements radiate sound during a door-closing event and how to optimize a door structure to achieve specific sound target in order to ensure the door closing noise quality, NVH engineers needed to look at contributions from different door subsystems. The use of statistical tools like Six Sigma can further help them to ensure the consistency in results. This paper explains the systematic approach used to characterize different element of door which contributes to the overall door slam noise quality through QFD (Quality Function Deployment) and contribution analysis. The different mechanisms contributing to door slam noise were studied. NVH characteristics (Acoustic transfer Function and Point Mobility) of the door structure and mounting locations were captured for correlating with the time - frequency spectrum of door slam event. Wavelet analysis was performed on door impact event to determine the critical frequency band contribute to noise. DOE (Design of Experiments) was constructed based on the analysis of results. Prototype modifications were conducted, the results of which are discussed in the paper together with their relative importance to work improvement in door closing noise. Finally the design intent solutions were developed together with component supplier and are validated on vehicle."
Investigation of Airflow Induced Whistle Noise by HVAC Control Doors Utilizing a ‘V-Shape’ Rubber Seal,"Doors inside an automotive HVAC module are essential components to ensure occupant comfort by controlling the cabin temperature and directing the air flow. For temperature control, the function of a door is not only to close/block the airflow path via the door seal that presses against HVAC wall, but also control the amount of hot and cold airflow to maintain cabin temperature. To meet the stringent OEM sealing requirement while maintaining a cost-effective product, a “V-Shape” soft rubber seal is commonly used. However, in certain conditions when the door is in the position other than closed which creates a small gap, this “V-Shape” seal is susceptible to the generation of objectionable whistle noise for the vehicle passengers. This nuisance can easily reduce end-customer satisfaction to the overall HVAC performance. The goal of this paper is to establish (1) contributing factors, (2) correlation of the whistle noise generation to the Strouhal number, and (3) an empirical equation to predict the whistle frequency as a function of fan speed and door gap geometry. Several potential solutions are also presented."
A Finite Element Method for Effective Reduction of Speaker-Borne Squeak and Rattle Noise in Automotive Doors,"Increasing sound quality with advanced audio technology has raised the bar for perceived quality targets for minimal interior noise and maximal speaker sound quality in a passenger vehicle. Speaker-borne structural vibrations and the associated squeak and rattle have been among the most frequent concerns in the perceived audio quality degradation in a vehicle. Digital detection of squeak and rattle issues due to the speaker-borne structural vibrations during the digital vehicle development phase has been a challenge due to the physical complexity involved. Recently, an effective finite element method has been developed to address structure-borne noise [1] and has been applied for detecting the issues of squeak and rattle in passenger vehicles due to vehicle-borne vibrations at vehicle, component and subcomponent levels [2, 3, 4, 5, 6, 7, 8]. In this paper, the speaker-borne structural vibrations are simulated accurately by adapting the critical audio loads in terms of equivalent structural excitations. The squeak and rattle analysis method is extended to predict the potential squeak and rattle issues in a door system on which the speaker is mounted. Using the method, the root causes for the issues are identified and counter-measures are developed to improve the audio quality in the system effectively. Audio tests are conducted to confirm the improvement in the audio quality with the counter-measures adapted. The finite element predictions show very close correlation with the tests regarding the squeak and rattle issues with the baseline design as well as the audio quality enhancement with the counter-measure."
Gear Lever Sound Quality Evaluation,"Vehicle sound quality has become lately one of the main topics of study in the automotive industry which is associated with the quality of the product. Into the automotive development the static operational sound quality is one of the attributes that is considered. The sounds produced through the manipulation of items like the doors and interior components (windows, seats, safety belts, windshield wipers, and others) generated for safety and warning purposes are items related to the vehicle quality for customers. Those sounds based on relative level of intensity, duration, harmony and degree of contribution are elements that the customer will retain in mind, an overall quality impression. The sound produced during gear lever manipulation is important to the customer in order that the event should transmit low intensity and robust and soft impression. The purpose of this work is to evaluate this kind of event using binaural recordings inside the vehicle through subjective and objective evaluations. Psychoacoustic parameters (loudness, sharpness and roughness) and time - frequency spectrum (Wavelet transform) are proposed to correlate objective results with the subjective perception of gear lever sound quality."
Constant Q Transform for Automotive NVH Signal Analysis,"The constant Q transform consists of a geometrically spaced filter bank, which is close to the wavelet transform due to the feature of its increasing time resolution for high frequencies. On the other hand, it can be processed using the well-known FFT algorithm. In this sense, this tool is a middle term between Fourier and wavelet analyses, which can be used for stationary and non-stationary signals. Automotive NVH signals can be stationary (e.g., idle, cruise) or non-stationary, i.e., time-varying signals (e.g., door closing/opening, run-up, rundown). The objective of this work is to propose the use of the constant Q transform, developed originally for musical signal processing, for automotive NVH (run up, impact strip and door closing) time-frequency analyses. Also, similarities and differences of the proposed tool when compared with Fourier and wavelet analyses are addressed."
The Use of a Simply Vibration Analysis Method for Optimization of Vibration Damping Material in Vehicle Panels,"With the use of common office software a simplified vibration analysis method is implemented. This method makes possible a quick evaluation of the data obtained with structural dynamics testing measurements, showing the maximum values of Frequency Response Functions (FRF) and a spatial graphic representation for these maximums; with this the regions of strong vibrations are identified. The dimensions and placement of the damping material to be applied in a metallic panel is defined based in the identification of these regions of maximum vibration. Successive tests can be quickly carried out with this method, making possible to achieve the better solution for elected frequencies. The application of this methodology in the optimization of damping material placement in vehicle doors results in a considerable enhancement in closing door noise."
Innovative Steel Solution for Doors,"Reducing CO2 emissions, improving safety, reducing car weight and cutting costs are the main constraints in the design of a new door. In partnership with a design office and a Tier 1 supplier, Arcelor has designed a generic door that reduces mass by 15% without impacting costs. This design was based on a reference (D segment / one of the European “best in class”). Functional validation was achieved by comparison with this reference and industrial feasibility was validated with the help of a partner (industrial door manufacturer). A range of innovations were implemented: This presentation will describe Design principles, Functional validation Industrial feasibility."
Cost-Effective Day & Night Marking Using Lasers,"“Day & night marking” is used in automobiles, aviation, instrumentation and computer keyboards to make buttons and controls (e.g. door locks, window controls, sound system adjustments, etc.) clearly visible under ambient illumination conditions varying from bright sunlight (day) to low light (night). Although it sounds simple, manufacturing these products cost-effectively in a small-batch production environment requires the use of a sophisticated, automated, laser-based tool."
The Effect of Seal Stiffness on Door Chucking and Squeak and Rattle Performance,"Traditionally, door seals are designed to achieve good wind noise performance, water leakage and door closing effort in a vehicle design and development process. However, very little is known concerning the effect of door seal design on vehicle squeak and rattle performance. An earlier research work at Ford indicates a strong correlation between the diagonal distortions of body closure openings (in a low frequency range 0 - 50 Hz) and overall squeak and rattle performance. Another research at Ford reveals that relative accelerations between door latch and striker in a low frequency region (0 - 50 Hz) correlate well with door chucking performance. The findings of this research work enable engineers to assess squeak and rattle and door chucking performance using vehicle low frequency NVH CAE models at a very early design stage. This paper is concerned with a sensitivity study of door chucking and squeak and rattle performance with respect to door seal stiffness using two performance metrics (diagonal distortions at closure openings and relative accelerations between latch & striker) mentioned above. It is found that door chucking performance improves with the increase of seal stiffness monotonically. Whereas overall squeak and rattle performance is dictated by match boxing modes of doors and liftgate that are in turn affected by seal stiffness. No special trend is observed in terms of squeak and rattle sensitivity with respect to seal stiffness."
Advanced Thermoplastic Composites for Automotive Semi-Structural Applications,"Composite materials have found applications in the aviation industry because of an appropriate combination of properties - high stiffness, high heat performance and lower specific gravities. The Automotive industry has similar needs, and the application of composites in semi-structural application is a natural next phase. This is also necessitated because of global emphases on fuel efficiency and safety considerations in automotive applications. In this paper, thermoplastic composite material technology solutions and case studies for a number of applications, such as front-end-modules, door modules and instrument panel carriers are presented. Since processing and material modeling of composites is of critical importance in the design process, this paper also describes a new definition of isotropic properties of long glass composites, and perhaps the only way of honestly comparing such materials. This method is now accepted as an European Alliance for Thermoplastic Composite (EATC) standard."
Application of Transient SEA for Vehicle Door Closure Sound Quality,"Transient Statistical Energy Analysis (SEA) is applied as an analysis technique and compared to measured data in this study. A transient SEA model for a door closure event is developed and compared to measured data to validate this model with measured acoustic and vibration responses. The validated model is then used to predict the effect of changes to component absorption, damping, stiffness, materials, and other properties. The basic theory of transient SEA and the transient SEA model used in the study are described, the validation between analytical model and measured data is shown, and the conclusions from the analysis of design changes to the vehicle components using this model are presented."
Cab Roof Strength Evaluation—Quasi-Static Loading Heavy Trucks,"This SAE Recommended Practice describes the test procedures for conducting quasi-static cab roof strength tests for heavy-truck applications. Its purpose is to establish recommended test procedures which will standardize the procedure for heavy trucks. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included."
Direction-of-Motion Stereotypes for Automotive Hand Controls,"The purpose of this SAE Recommended Practice is to present design recommendations for the direction-of-motion of hand controls found in passenger vehicles, multipurpose vehicles, and trucks. These recommendations are based on recent and past human factors research and are important considerations in the design of control layouts."
Cranes—Access and Egress,"This recommended practice specifies criteria for steps, stairways, ladders, walkways, platforms, handrails, handholds, guardrails and entrance openings which permit access to and from operator, inspection or maintenance platforms on mobile cranes parked in accordance with the manufacturer’s instruction. It also presents requirements for guards and restraints as related to moving parts."
Ambulance Modular Body Evaluation-Quasi-Static Loading for Type I and Type III Modular Ambulance Bodies,"This SAE Recommended Practice describes the test procedures for conducting quasi-static modular body strength tests for ambulance applications. Its purpose is to establish recommended test practices which standardize the procedure for Type I and Type III bodies, provide ambulance builders and end-users with testing procedures and, where appropriate, provide acceptance criteria that, to a great extent, ensures the ambulance structure meets the same performance criteria across the industry. Descriptions of the test set-up, test instrumentation, photographic/video coverage, and the test fixtures are included."
Automated Fastening of Aircraft Cargo Door Structures with a Standard Articulating Robot System,"The demand of flexible and cost-efficient solutions for automated fastening systems inspired us to develop the robot and end-effector technology to fulfil the customer's requirement for a highly accurate, automated robot based drill and fastening system for an aerospace application. This paper describes an innovative robot cell for drilling and solid riveting installation in cargo door structures of a single aisle aircraft at EUROCOPTER in Germany. The required absolute positioning accuracy is reached by using a special compensation package for the robot that was developed by BROETJE-Automation. Our customer's application required a completely new type of end-effector; installing solid rivets and capable of operating within the inner structure of the cargo doors. This solution demonstrates how standard robots equipped with a mature compensation method by BROETJE-Automation resulted in a highly flexible and cost-efficient light weight automation response."
Re-Design for Automotive Window Seal Considering High Speed Fluid-Structure Interaction,"Automotive window seal has great influence on NVH (Noise-Vibration-Harshness) performance. The aerodynamic effect on ride comfort has attracted increasing research interest recently. A new method for quantifying and transferring aerodynamics-induced load on window seal re-design is proposed. Firstly, by SST (Shear Stress Transport) turbulence model, external turbulent flow field of full scale automotive is established by solving three-dimensional, steady and uncompressible Navier-Stokes equation. With re-exploited mapping algorithm, the aerodynamics pressure on overall auto-body is retrieved and transferred to local glass area to be external loads for seals, thus taking into account the aerodynamics effect of high speed fluid-structure interaction. This method is successfully applied on automotive front window seal design. The re-design header seal decreases the maximum displacements of leeward and windward glass with 9.3% and 34.21%, respectively. The improvement of fitting stability shows the effectiveness this seal re-design considering high-speed fluid-structure interaction."
Mass Benchmarking Using Statistical Methods Applied to Automotive Closures,"Understanding the lightweighting potential of materials is important in making strategic decisions for material selection for a new vehicle program. Frequently benchmarking is done to support these decisions by selecting a reference vehicle which is believed to be mass efficient, then using the teardown mass data to set targets for the vehicle under design. In this work, rather then considering a single benchmark vehicle or a small set of vehicles, we looked at a large sample of vehicles over a range of sizes and segments (approximately 200 vehicles). Statistical methods were used to identify mass drivers for each subsystem. Mass drivers are the attributes of the vehicle and subsystem which determine subsystem mass. Understanding mass-drivers allows comparisons across vehicle size, segments, and materials. Next, we identified those vehicles which had subsystems which were much lighter than the average after adjusting for mass drivers. This set was defined as mass-efficient designs. We then focused on the lightweighting gained by material selection for these mass-efficient designs. This paper focuses on four body closures systems: side door, hood, decklid, and hatchback door. Results include the identification of mass drivers and predictive equations for closure structure mass for both average designs and mass efficient designs; The influence of material selection on mass for both average and mass-efficient designs; and observations on the diminished mass savings achieved at the system level when there is a mass savings due to material substitution at the structure level."
Effect of load slope time (LST) and load adaptor position (LAP) on side door strength of passenger cars: A deformation mapping matrix (DMX) approach,"Side impact collisions are one of the most frequently occurring road accidents leading to occupant injury and even death. To provide better safety to occupants during such collisions, side doors and side body structures in modern passenger cars have been designed to absorb the impact energy and reduce the depth of intrusion into the passenger compartment. Side impact performance components are often evaluated by conducting a dynamic full vehicle crash test and a quasi-static side door intrusion test. The Indian regulation for side impact performance evaluation comprises of the quasi-static side door intrusion test. This paper highlights the variation in crush strength performance viz., initial crush resistance, intermediate crush resistance and peak crush resistance, due to the difference in the rate of load application as per IS12009:1995. The paper presents the deformation mapping matrix (DMX) approach to study the variation in results due to load slope time (LST) and load adaptor position (LAP)."
Simplified Side Impact Test Methodologies for Door Interior Trim Armrest in Automotive Vehicle,"The complete evaluation of the side vehicle structure and occupant protection is only possible by the full-scale side impact crash test. But auto part manufactures, such as door trim makers can't conduct the test especially when the vehicle is under developing process. And important information and components for estimating crash performance is restricted. With the proposed design procedure for the door trim by a simple impact test method was demonstrated to evaluate the abdominal injury. In addition to simple test, Euro-NCAP test result that is conducted by referenced full-scale test in Korea is compared with several test results. In conclusion, this simple test method have similar trend for abdominal injury index so that it is possible to present guidelines of door armrest design to carmaker at the early stages of vehicle program development."
Sealing and Structural Enhancement System for the Rear Cargo Ramp of a C-130 Aircraft,"At flight levels above the ceiling of 10,000 feet, during the operational phase of a sensor deployment system for a C-130 aircraft, it becomes necessary to seal the cargo hold to maintain pressure for the safety and comfort of the crew and operators. In order for the sensor deployment System to have full mission support capabilities for DoD reconnaissance needs, a system must be designed where-by the cargo area may be sealed once the system has been deployed. Currently, with the sensor pod in position, the ramp can be closed to within a few inches of the locked position. The door in this position, for stability during flight, must be locked and structurally supported to maintain the aircrafts design requirements. This presents the first of a series of issues that must be examined for the success of the final design. To seal the remaining area, an expanding “bladder-seal” has been developed. This sealing device will ideally include a means of “holding” onto both the upper door and lower ramp of the aircraft simultaneously. The systems presented will create a significant advancement to the capabilities of the existing sensor deployment system for a C-130 aircraft and for the C-130 itself. This design will be completely capable of being used on any C-130 aircraft produced and will have the same universal mounting system as the current sensor deployment system."
Electromagnetic Field Analysis for Smart Key Antenna,"Currently, the drivers are able to control a door lock at a distant point from a vehicle. Recently, a door lock system has been developed to detect an owner approaching and to unlock the door when he/she touches the door handle. In this system, an antenna detects the existence of the owner with an electrical key near the vehicle. Since this detection performance of the antenna (directivity) varies in the operating area, it is essential to recognize directivity and confirm that there is unoperating area. In this report, we describe an example of predictive calculation on directivity of an antenna using the electromagnetic field analysis."
Retention Characteristics of Production Laminated Side Windows,"Field accident data have demonstrated that occupant ejection during vehicle rollover is associated with a high risk of serious and fatal injury. Although it has been demonstrated that seat belt use is highly effective in preventing occupant ejections, it has been argued that occupant containment during rollover can be accomplished with the use of laminated side glazing. This study was conducted to evaluate the retention characteristics of production laminated side windows. The current vehicle fleet was surveyed for vehicles equipped with production laminated side glass. The survey examined relevant window system parameters including glass retention system, glass configuration, and window geometry. A representative subset of five front door systems from several manufacturers was chosen for further evaluation. In addition, one legacy rear door system with laminated glass was included for comparison. Drop tests were conducted on the production component door-glass systems utilizing an 18 kg (40 lb) headform at an impact speed of 24 km/h (15 mph). None of the tested window systems retained the headform under these loading conditions. Given the results of this study, together with the NHTSA's previous measurements of occupant effective mass, it is concluded that production laminated side glass is not an effective barrier to occupant ejection during rollover."
The Impact of the Digital Human Modeling on the Aircraft Interior Projects,"The main objective of this work is to show a broad view of Digital Human Modeling software as a tool for aiding interior design projects for aircrafts. This will be achieved by showing digital manikins and their use during the development project of an aircraft interior. The time allocated to the design stage could be shortened and the costs concerning mock-up fabrication and certification were lowered because of this program's application during the entire process. The influence can be noted because of the ease to study monuments on high-density configurations, usability and accessibility of the door handles and on-board attendant visibility, etc. This paper is merely conceptual and do not involve existing aircrafts data or in development."
System Level Noise Source Identification and Diagnostics on a Vehicle Door Module,"Noise problems are often system issues rather than component issues. Component manufacturers have been putting continued efforts into constantly improving the quality of their products. There are numerous tests and standards to assess the vibro-acoustic performance of individual components. But once all components are put together, the system response might be entirely different from those of individual components. Typical system level testing has primarily been used to identify bad assembled products from good ones. These tests are usually done as part of a quality control process and slow down production. Such tests usually provide little information about the root causes of noise and vibration problems and no insight into improving engineering designs for noise abatement. This paper presents a new way of conducting system level noise diagnoses by using the Helmholtz Equation Least Squares (HELS) based Nearfield Acoustical Holography (NAH) technology [1]. This approach allows for reconstruction of all acoustic quantities, including the acoustic pressure, particle velocity, and acoustic intensity, and creating 3D acoustic images produced by an arbitrary source based on the acoustic pressures measured on a hologram surface at very close range to the source. It enables one to establish a direct correlation between sound and vibration. The current study involves a noise diagnostic test on a vehicle door assembly to understand system level interaction of the motor and the door module to compliment continued efforts to refine the motor to manufacture quieter assemblies. To identify noise sources, a conformal microphone array, covering the entire door surface was used to measure the acoustic pressures. This data was used to reconstruct the acoustic pressure, normal velocity, and acoustic intensity on the door module surface. In particular, the acoustic intensity and normal surface velocity were analyzed to identify the noise sources and understand the noise generation mechanisms."
Implementation of a correlation technique for fuel tank sled crash test,"The fuel tanks produced in sheet metal forming needs to attend safety requirements regarding the vehicle collision. One of the validation tests is the sled crash test. This test is based on the impact of a sled with a certain profile and energy (defined by rules) against a fuel tank. During the crash are evaluated: deformation, internal pressure, cracks, leaks and the energy absorbed. To avoid trial-and-error methods in the product development stage, the use of numerical simulation has increased in the past years and made the validation process faster and cheaper. One difficulty of this procedure for validation of numerical results is the correlation between the level and the deformation mode of the tank, once the internal pressure and the energy can be measured by special sensors. The main objective of this work was to propose a methodology to correlate the deformed geometry of the fuel tank, using a 3D scanner, with the numerical simulation results. The software used to simulate the crash was Radioss, which has a suitable formulation for events involving large non-linearity. The results are promising and the methodology implemented can be used for other products that involves crash test in the validation, such as bumpers and doors."
Development and Application of an Enhanced SID-IIs Dummy for Analyzing Side Impact Kinematics,"Due to the relative high speed and short distance between the door and occupant, side impact presents a challenging task when analyzing the input force from the door to the occupant. The new FMVSS214 Final Rule in 2007 and the new NCAP in 2008 mandated the use of a SID-IIs in the oblique pole impact test and in the rear seat during an MDB side impact test. Therefore, a high-precision measurement and calculation of the three-dimensional dummy kinematics, as well as the interaction of force inside the dummy (internal force) and force exerted from outside the dummy (external force) will help provide efficient evaluation of design requirements for the door trim and supplemental restraint systems that meet legally mandated requirements. This paper demonstrates that the SID-IIs three-dimensional kinematics and external forces can be calculated with a high degree of precision through the addition of angular rate sensors and force transducers, and describes the application of the technique to vehicle development."
Design of Dual Sliding Door Mechanism for a Small Sized Car,"Swing-out doors can easily cause damage to adjacent parked vehicles in tight parking spaces. Also, they are not traffic-friendly when the vehicles are parallel parked on busy road sides. This paper makes an attempt to come up with an innovative to design and develop a mechanism for dual sliding doors for a small sized car. The doors are supported only on two points of contact as compared to the usual sliding minivan doors which have three contact supports for sliding. These two points are called the “Upper control link and Lower support arm”. To open the door, first the door, has to push out by 90 degrees and then it has to slide in the fore-aft direction to open or close. For the doors, a track was placed just below the window at the beltline location and a triangular sub-roller assembly was designed for sliding motion. A rail was placed on the rocker panel of the space frame which has three rollers assembled in such a way that they would compensate for the weight of the door and rigidly secure the door during sliding. This paper explains the mechanism in detail and also discusses safety issues linked to selection of engineering materials for the doors."
Load Path Considerations for Side Crash Compatibility,"Heavier, larger pickups and SUVs are bound to encounter lighter, smaller passenger vehicles in many future accidents. As the fleet has evolved to include more and more SUVs, their frontal structures are often indistinguishable from pickup fronts. Improvements in geometric compatibility features are crucial to further injury prevention progress in side impact. In corner crashes where modern bullet passenger car (PC) bumpers make appropriate geometrical overlap with target PC rocker panels, concentrated loads sometimes disrupt foam and plastic bumper corners, creating aggressive edges. In situations where sliding occurs along the structural interface, these sharp edges may slice through doors, panels and pillars. End treatments for such bumper beams should be designed to reduce this aggressive potential. The experimental comparison presented here demonstrates that load path compatibility can provide a means by which severe door intrusion due to oblique corner impacts may be reduced without severe weight penalties to the vehicles involved."
A Dynamic Sled-to-Sled Test Methodology for Simulating Dummy Responses in Side Impact,"This paper describes the development of a sled-to-sled test methodology to simulate the occupant responses in different side impact cart test modes. For evaluation of various inflatable restraints (Thorax SAB, Head-Thorax Combo SAB, Pelvis-Thorax Combo SAB), the simulation of ‘gap closure’ between dummy and door is desirable to achieve satisfactory SAB performance, besides obtaining good correlation of occupant responses between full-vehicle tests and sled tests. This methodology uses a combination of three sleds - Bullet, Door, and Seat sleds to simulate the entire door velocity profile in two phases - Phase I: Gap Closure till Door-Dummy contact occurs, Phase II: Door-to-Dummy contact till separation. The initial pre-crash distance between dummy-to-door trim is achieved by positioning the Door sled relative to the Seat sled (with dummy). The Bullet sled strikes the stationary Door sled with a pre-determined initial velocity, which accelerates the Door sled to a peak velocity within a predetermined time from contact (also dummy-to-door contact velocity) to simulate Phase-I of the door velocity profile. The Door sled then strikes the stationary Seat sled with Dummy. After door-to-dummy contact, the Bullet and Door sleds are decelerated by a VIA decelerator to simulate the Phase-II of the Door velocity profile."
Hybrid Design for Automotive Body Panels,"The increasing trend for electric mobility adoption brings new challenges to the automotive industry, requiring a new approach to the manufacture processes, materials adopted and adaptation the market needs. The conventional technologies used to manufacture automotive parts imply significant overhead costs (tooling, assembly, etc.) which can only be justified by large series. The need of light and cost effective materials was the driving force of this study, acknowledging that the growth of the electric vehicles market will be driven by price. The study aims to deliver a hybrid design material solution that would offer quality and security to the vehicle, affordable to everyone, developing engineered solutions in terms of design and production process. To the study were considered exterior body panels that are conventionally manufactured by sheet metal stamping or conventional thermoplastic injection, both having associated high investment costs related with tooling. To follow up this case study was defined as constrains that small series should be considered and weight reduction has to be achieved. The adoption of engineered materials leading to hybrid body panel's configuration was studied with increased resistance and reduced weight, using processes with low cost assembly operations and low tooling investment for a start. Structural reinforcement inserts were used on the test case to provide the desired results on the final component behavior. The approach taken, considered different materials and methodologies focusing on the use of DCPD RIM components having as baseline the materials used nowadays in the automotive industry for the same type of exterior body panels. For deeper understanding on exterior panels' state of art, an analysis through several vehicle doors was made, analyzing the materials used and their combination. As a result, different combinations of materials were considered as adequate for weight reduction and for production on small production series. Virtual simulation of two exterior body panels' solutions was done demonstrating the potential of DCPD as a hybrid solution to deliver structural consistence in conjunction with weigh reduction at a reduced cost."
Automation for Unprecedented Production Rates,"Unprecedented rates in Boeing 737 aircraft production have driven a need for an increase in capacity in fuselage manufacturing and assembly. This paper will discuss the requirements by Spirit AeroSystems to add capacity, and the new and upgraded machinery provided by Broetje Automation in response to these requirements. Production areas found to require additional capacity included galley and entry door skin fastening, as well as frame fastening in upper and lower lobes. Three new Mobile Panel Assembly Cell (MPAC) machines were installed in rapid succession for efficient and flexible production of door panels. For frame fastening of upper and lower lobes, three existing machines were taken out of production one at a time for a comprehensive upgrade resulting in process speed increases of more than 40%."
Oil Filter Clogging Rule - Correlation between Mileage and Lab Test Clogging,"Oil Filter change interval is widely defined as a mileage, expressed in Kilometres/Miles of the Vehicle driven. On the other hand, for convenience, repeatability and differentiation reasons, the Filter life time is evaluated in the laboratory test bench according to standard test methods. The Life Time is expressed in grams of calibrated dust injected into the filter inlet so as to clog it. The most commonly used test standard is ISO 4548-12 [7]. So far, there is no widely known and recognized relation between the service time in kilometres and the dust holding capacity according to ISO standard. The purpose of the following study was to establish a relationship between ISO standard dust capacity and the ability of the filter to successfully achieve the service interval in 90% of cases. A large number of used filters were collected and analysed in order to conduct a statistical analysis. Impacts of fuel type, engine displacement and road conditions were identified. At the end a clogging rule was established. The paper concludes that for some filter applications, it is possible to reduce the required ISO dust capacity which opens the door to filter size reduction or enhanced engine protection through higher filtration efficiency."
Development and Validation of Numerical Model for Standardized Oberst Beam Test (ASTM E 756-98),"Currently, the simulation models in acoustics and vibrations are built considering only the main structures of the vehicle, as its basic structure (Body-in-white, BIW), doors, dashboard, and so on. To take into account the contribution of components with less influence (such as carpets, seats, sound insulation, and so on) in the behavior of the overall response of the model, the average characteristics of these materials are inserted evenly distributed in these models. However, to obtain models with better correlation levels is necessary to consider local characteristics of the application of these components. In this work was developed and numerically validated, the model that describes the standardized test of “Oberst Beam” (ASTM E 756-98) to obtain the damping of the blankets used for damping of the panel vibration. With these characteristics, in future work, is expected to be possible, also with a good correlation, consider the effect of these materials on whole vehicle."
Numerical Simulation of the Vibro-Acoustic Behavior of a Vehicle under Operating Conditions,"Currently the numerical simulations of the vibro-acoustic behavior of vehicles are built considering only major structures, such as its basic structure (body in white), doors, dashboard etc. To take into account the contribution of other components (such as trims, seats, sound insulation etc.) to the overall response of the model, the average characteristics of these materials are inserted globally in this model. However, for more correlated models is necessary to consider local characteristics of these components. This work presents the numerical procedure for simulating the effect of the structural damping of viscoelastic coatings and the acoustic absorption of the trims such that its effects can be considered in the model of the full vehicle. The operating forces applied to the model were estimated from the laboratory and road tests using the SPC/TPA technique. Furthermore, the model enables the subjective evaluation of the noise from the auralization/synthesis based on numerical frequency response functions and road test data."
A Study on New Approach of Optimization for the Automotive Plastic Interior Parts,"Carmakers have tried to lower the vehicle weight for raising fuel efficiency. This trend involves a trade-off with the vehicle stiffness. In automobile interior parts, the thickness has needed to be decreased for the weight reduction but this makes the stiffness worse. A new approach for improving the stiffness due to the weight reduction is required and various optimization methods at early development stage have been introduced currently. However, it is difficult to apply optimization for the interior parts since many interior parts' structures generally depend on the design. But as studying the structure in detail, we discovered some factors that affect the performance without depending on design. The door trim is selected for optimization item because it has many characteristics of automobile interior parts. In our case study, the factors that improve the performance of door trim without changing design are considered as fastener position and flange rib layout. The optimization process for door trim was established. Size optimization is used for Fastener position and Topology optimization is used for Flange rib layout. As a result, the 1st mode frequency is improved by about 5% and thermal displacement is reduced by about 25% in comparison with the initial model."
DPIV Measurements of the HVAC Aerodynamics Inside a Passenger Car,"DPIV (Digital Particle Image Velocimetry) measurements of the HVAC (Heat, Ventilation and Air Conditioning) system aerodynamics inside the compartment of a passenger car will be presented. The measurements were carried out in a commercial version of a car. No modifications were made to the car other than substituting the doors on the passenger side for transparent acrylic sheets. In DPIV the flow is seeded with particles with size in the order of microns and the flow is illuminated by a planar pulsed laser sheet. The particles scatter the light and one or more high speed cameras, synchronized with the laser pulses, record images of the illuminated particles. Image processing of the obtained images allows the calculation of the velocity flow field. The seeding for these experiments was produced using a custom made Laskin nozzle atomizer and olive oil. Flow velocities were measured in several vertical longitudinal and transverse planes, as well as in horizontal planes, covering very large areas inside the cabin of the car with high spatial resolution. Results showing the mean and the standard deviation of the velocity flow fields inside the cabin will be presented. The work reveals how DPIV can be used in the design and validation process of HVAC systems, in order to study the instantaneous flow fields and the main structures inside the cabin for each HVAC configuration desired."
Research on Torsional Characteristic of Separate Frame Construction for a Light Off-Road Vehicle,"A key problem of designing a light off-road vehicle with separate frame construction is to improve its torsional characteristic, which has a significant influence on the performance of the vehicle. Inevitably, a certain distortion of the body would be produced by the vibration and impact passing from the road. In present research, an analysis model of light off-road vehicle is established based on the theories and methods of finite element (FEM). The static stiffness of the body is simulated and the deformation of openings on the body, mainly the windows and the doors of the vehicle is studied. On the working conditions of torsion and braking combination, torsion and cornering combination, diagonal dangling, ultimate torsion of unilateral wheels and diagonal wheels, the static strength of separate frame construction is studied as well. The stress concentration regions are obtained according to the results of simulation. Theoretically, this paper studied the torsional characteristic of separate frame construction in terms of static stiffness and static strength and the most vulnerable regions are figured out, which offers an important support for the optimization of vehicle structure."
Aeroacoustic Noise Generated by Air Flowing through a Slit in an HVAC System,"Air flowing through a narrow slit sometimes generates noise. This phenomenon has been identified in some parts of automobile HVAC systems. The noise annoys drivers and passengers and causes deterioration in the automobile’s quality. Simply sealing the gap is a way to avoid such flow noise. In an HVAC system, however, the doors that control the air flow are openable, and the door slits, which are difficult to eliminate, emanate the noise in transient conditions. The noise is well known, but the mechanism of noise generation has not been well studied to date. Computational fluid dynamics (CFD) has been a useful tool for air flow studies, but commercial CFD programs usually use a turbulence model such as Reynolds-averaged Navier-Stokes (RANS); in addition, the flow behavior result depends on the model selected in the calculation. In this study, direct numerical simulation (DNS) of the compressible subsonic flow without a turbulence model is adopted to investigate the flow through a narrow slit and its associated noise generation mechanism. The numerical results show the relationship between the noise and the unsteady vortices created through the slit. This study also explains the process of slit noise creation by comparing the force caused by vortices from the wall to the air and the noise."
Experimental Investigation on Mechanical Properties and Vibration Damping Frequency Factor of Kenaf Fiber Reinforced Epoxy Composite,"Kenaf Fiber regarded as industrial crop for different applications. It is one of the most important plants cultivated for natural fibers globally. Natural fibers such as kenaf fibers are getting attention of researchers and industries to utilize it in different composites due to its biodegradable nature. In this present investigation mechanical properties, vibration damping frequency factor and thermogravimetric analysis of kenaf fiber reinforced epoxy composite (KFREC) have been evaluated and reported. The tests were conducted with different weight categories of kenaf fiber such as 20%, 25%, 30% and 35%. The effects of fiber content on tensile, flexural, impact strengths, hardness and thermal decomposition properties of the composite were determined. The failure mechanism and damage features of the KFREC were categorized using Scanning Electron Microscope (SEM). The results indicate that the increase in the fiber content decreases the damping vibration factor (ζ) correspondingly. The lowest value of the damping vibration factor was recorded as 0.033 for 35% weight content of Kenaf fiber in the composite. The maximum value of hardness, tensile, flexural, and impact strengths were noted as 447 BHN, 45.62 MPa, 124 kN and 13.2 J respectively and the effective thermal decomposition range was 378.64 - 442.18 °C for 35% of kenaf weight content KFREC. From the results it is identified that the kenaf fiber at 35% weight content reinforced with epoxy resin will be suitable for structural application in automobiles such as bumper beams, door panels and front modules. In addition to that the light weight nature of the kenaf fiber will help in achieving fuel economy in automobiles."
Crash-induced Loads in Liftgate Latching Systems,"Automotive liftgate latches have been subject to regulation for minimum strength and inertial resistance requirements since the late 1990’s in the US and globally since the early 2000’s, possibly due to liftgate ejections stemming from the first generation Chrysler minivans which employed latches that were not originally designed with this hazard in mind. Side door latches have been regulated since the 1960’s, and the regulation of liftgate, or back door latches, have been based largely on side door requirements, with the exception of the orthogonal test requirement that is liftgate specific. Based on benchmarking tests of liftgate latches, most global OEM’s design their latches to exceed the minimum regulatory requirements. Presumably, this is based on the need to keep doors closed during crashes and specifically to do so when subjected to industry standard tests. The focus of this paper is to understand the specific loads seen by center-mounted liftgate latches when exposed to various industry standard tests, as well as some foreseeable crash conditions currently not addressed by the standard tests. This paper explores the use of CAE analysis to understand the specific structural and inertial loads liftgate latches are exposed to in various rear and side crash tests, in order to better understand the design requirements for liftgate latches to ensure passenger compartment integrity and minimize the risk of occupant ejection through the liftgate closure. Various standard crash tests, vehicle body types and cargo load cases are explored as well. A methodology is presented which shows how the various load cases can be obtained and used for development of new liftgate latches. This paper does not deal with roll over load cases, which is a subject of ongoing research and will be presented in a subsequent paper."
The Effects of Internal Friction on Automotive Latch and Release System Behavior,"Physical tests and analysis of a typical automobile latch and outside handle release mechanism are performed to determine the effects of friction on the systems dynamic response. An automobile side door outside handle, outside handle rod linkage, and latch are mounted to a rigid fixture that is constrained by bearings to a “drop tower.” The fixture is released from controlled heights onto a compliant impact surface resulting in a constant duration acceleration transient of varying amplitude. An instrumented door latch striker is designed into the fixture to engage the latch. The pre-drop interface load between the latch and striker is adjusted allowing its effect on the dynamic behavior to be characterized. The latch position and the interface load between the latch and striker are monitored throughout the test. The results of the test show that friction forces internal to the latch significantly affect the quasistatic and dynamic behavior of the latching system."
Understanding the Stick Slip Behavior of Plastics and Target Setting: An OEM Perspective,"Automotive OEMs are aggressively using different materials for interiors due to value proposition and variety of options available for customers in market. Excessive usage of different grade plastics with zero gap philosophy can cause stick slip effect leading to squeak noise. Even though systems and subsystems are designed using best practices of structural design and manufacturing tolerances, extreme environmental conditions can induce contacts leading to squeak noise. Appropriate selection of interface material pairs can minimize the possibilities of squeak conditions. Stick-slip behavior of different plastics is discussed in the present study, along with critical parameters during material compatibility testing in a tribological test stand. Friction coefficient of different material pairs for a defined normal load and sliding velocity are analyzed for patterns to recognize squeaks versus time. An OEM perspective is presented with focus on material selection using objective metrics like coefficient of friction and set targets for raw material suppliers regarding compatible materials. In the next step, an algorithm based on machine learning approach has been developed for estimating stick-slip performance."
Dust-Sized Sensors Could Create “Electroceuticals”,"University of California, Berkeley engineers have built the first dust-sized, wireless sensors that can be implanted in the body, bringing closer the day when a Fitbit-like device could monitor internal nerves, muscles, or organs in real time. These batteryless sensors, called neural dust, can also be used to stimulate nerves and muscles, opening the door to “electroceuticals” to treat disorders such as epilepsy, stimulate the immune system, or tamp down inflammation."
Robotic Modules Modify Their Environment for Specific Tasks,"Given the exact parameters of the task at hand, a robot can assemble a car door or pack a box faster and more efficiently than a human, but such purpose-built machines are not suited for much else. With that in mind, the history of robotics research is marked by devising ways of giving machines more and more autonomy. To achieve that end, robots must be able to sense features of never-before-seen environments and know how to interact with them."
"Horsepower, kilowatts compete at 2019 GENEVA MOTOR SHOW","Is Europe getting serious about electric vehicles? Look no further than the EV-intensive 2019 Geneva motor show. There still was plenty of old-school horsepower making news at this year's Geneva motor show in early March, but there was no question it's fast becoming a kilowatt kinda world. The number of electric and electrified vehicles-concept and production-ready-on display made it abundantly clear that at least in Europe, electrification's “if” definitely is no longer a question. And the “when” appears to be pretty darn soon. Although there were legitimate newsmaking vehicle introductions all over the Geneva show, the poster child for Europe's intensifying enthusiasm for electrification had to be Honda's E Prootype (see page 10), a near-production version of the universally praised Urban EV Concept shown at Frankfurt in 2017. The Urban EV's funky front bench seat is replaced by a familiar seating setup and the twin suicide doors also have morphed into four conventionally-hinged doors, but the e Prototype remains alluringly proportioned for the European market. And its rear-drive layout indicates Honda may not intend the production version to be a dull urban-transport pod."
Aircraft Landing Noise Reduction Liners,"NASA Langley Research Center has developed two new implementations of acoustic liners for aircraft noise reduction whereby curved channels within tight spaces can be outfitted to provide noise reduction. The two implementations are flap side edge liners and landing gear door liners for airframe noise reduction. In these applications, the acoustic liner is designed primarily to reduce aircraft noise that occurs during landing, which will help aircraft comply with increasingly stringent airport noise restrictions."
Door Latch Vulnerability to Rollover Induced Loads,"Light truck and SUV rollovers often involve ground contacts at the roof rails or door sills that can induce significant vertical shear loads at the latch/striker interface. These vertical loads are not evaluated in Federal Motor Vehicle Safety Standard testing yet they are known to cause latch failures. Such failures expose both belted and unrestrained occupants to increased injury risk. An example of two such failures can be found in open literature in a single van rollover test. A simple vertical load test for latches is described by the authors and evaluated for discrimination, suitability and repeatability. This test was applied to an array of current and past generation latches found on many popular SUVs and light trucks. A large range of failure loads was encountered. A review of the structural features of the superior performing test samples suggests simple modifications that could dramatically improve performance of the remaining latches. Improved performance in this vertical load test could be expected to translate to fewer unwanted door openings and ejections in field accidents."
Invisible Advanced Passenger-Side Airbag Door Design for Optimal Deployment and Head Impact Performance,"Hard panel types of invisible passenger-side airbag (IPAB) door system must be designed with a weakened area such that the airbag will deploy through the Instrument Panel (IP) in the intended manner, with no flying debris at any required operating temperature. At the same time, there must be no cracking or sharp edges in the head impact test (ECE 21.01). If the advanced-airbag with the big difference between high and low deployment pressure ranges are applied to hard panel types of IPAB door system, it becomes more difficult to optimize the tearseam strength for satisfying deployment and head impact performance simultaneously. We introduced the ‘Operating Window’ idea from quality engineering to design the hard panel types of IPAB door applied to the advanced-airbag for optimal deployment and head impact performance. To accurately predict impact performance, it is important to characterize the strain rate."
Grade and Gage Sensitivities to Oil-Canning Loads of a Door Assembly Considering Forming Effects,"A finite element methodology, based on implicit numerical integration procedure, for simulating oil-canning tests on Door assemblies is presented. The method takes into account nonlinearities due to geometry, material and contact between parts during deformation. The simulation results are compared with experimental observations. Excellent correlation between experimental observations and analytical predictions are obtained in these tests. Armed with the confidence in the methodology, simulations on a door assembly are conducted to study the gage and grade sensitivities of the outer panel. The sensitivity studies are conducted on three different grades of steel for the outer panel. Further studies are conducted to understand the effects of manufacturing (forming operation) on the oil canning behavior of door assembly. Results demonstrate the utility of the method in material selection during pre-program design of automotive structures."
Optimization of the Side Swing Door Closing Effort,"In the automotive industry, a lot of attention has been paid to the effort required for opening/closing the doors, and for a good reason. The door closing and opening effort creates an impression in the customer's mind about the engineering and quality of the vehicle even before he or she steps into it. Although this is such an important issue, the precise quantification of what constitutes a good performance target for the door opening/closing effort, has remained somewhat elusive. Thumb rules and best practices abound in the automotive industry. Some of the rules and best practices have focused on setting certain targets for the energy required to shut the door from a small open position (around 10-15 degrees). This target can be misleading. The purpose of this paper is to present an ADAMS® simulation model that includes all the different components of the door design. The complete opening/closing motion is a result of the interaction of the different components of the door closing system, such as the latch, weather seal, energy loss due to air-binding effect, the inclination of the hinge axes, check-link etc. The analysis simulates the entire opening/closing motion and the energy/force required during this motion. Analyzing the details of the door opening/closing motion of different vehicles, and associating this information to the customer dissatisfaction figures from sources like JD Power quality survey, enables us to more precisely quantify the target performance that will result in greater customer satisfaction."
Developments in Thermoplastic Door Modules,"The use of door modules as a pre -assembled functional unit inside a car door is discussed. This includes reasons why a door module should be used and why a long glass fiber reinforced polypropylene (PP) product is a good material of choice. As an example the development of the door modules for the new Ford Fiesta is given, including the mechanical and production design of the StaMax® P long glass PP carrier. * Special attention is paid to the excellent dimensional reproducibility of this material which is critical for door module designs in which the carrier also manages the wet and dry separation (e.g. “sealed” designs). Further integration potential for future door modules is also highlighted."
A Design Study to Determine the Impact of Various Parameters on Door Acoustics,"Once the design of a door sheetmetal and accessories is confirmed, the acoustics of the door system depends on the sound package assembly. This essentially consists of a watershield which acts as a barrier and a porous material which acts as an absorber. The acoustical performance of the watershield and the reverberant sound build-up in the door cavity control the performance. This paper discusses the findings of a design study that was developed based on design of experiments (DOE) concepts to determine which parameters of the door sound package assembly are important to the door acoustics. The study was based on conducting a minimum number of tests on a five factor - two level design that covered over 16 different design configurations. In addition, other measurements were made that aided in developing a SEA model which is also compared with the findings of the results of the design study."
A Comprehensive Study of Door Slam,"As part of an ongoing technical collaboration between Ford and Rouge Steel Company, a comprehensive study of door slam event was undertaken. The experimental phase of the project involved measurements of accelerations at eight locations on the outer panel and strains on six locations of the inner panel. Although slam tests were conducted with window up and window down, results of only one test is presented in this paper. The CAE phase of the project involved the development of suitable “math” model of the door assembly and analysis methodology to capture the dynamics of the event. The predictability of the CAE method is examined through detailed comparison of accelerations and strains. While excellent agreement between CAE and test results of accelerations on the outer panel is obtained, the analysis predicts higher strains on the inner panel than the test. In addition, the tendency of outer panel to elastically buckle is examined. The implications of the buckling of the outer panel are discussed. The effects of thickness distribution and plastic strains introduced on the inner and outer panels due to forming are studied. The results show that the strains on the inner panel can be significantly influenced when forming effects are accounted for. The effect of forming on the accelerations of the outer panel can be less intuitive. This is possibly due to the buckling of the outer panel during the slam event."
New Methods of Side Impact Simulation for Better Waveform Reproduction and Door Interaction,"As a result of the severity of occupant injuries during a side impact collision, there has been an escalating demand for accurate component level side impact simulation. Three major components for accurate simulation are accurate door velocity, door to seat relative velocity, and door deformation. This paper shows data demonstrating accurate door velocity reproduction, presents test methods to passively and actively control relative seat to door velocity in a non destructive manner, and presents test methods to simulate real time door deformation in a destructive manner. All side impact waveforms include a negative acceleration, high positive accelerations, high jerk, and high frequency content that add to the complexity of this simulation. The simulated door velocity is produced by means of a MTS deceleration brake that only applies a braking force during the deceleration portion of the waveform to maximize acceleration capacity. The proposed methodologies introduce a controlled damper technology (patent pending) to actively control the transmitted forces between independent components during the simulation."
Analysis of the Influence of the Seal Structure on Door Closing Force for SANTANA,"In order to evaluate the influence of the seal structure on door closing force, nonlinear finite element method is introduced to analyze compression deformation of a door seal for SANTANA (name of the car made by Shanghai Volkswagen Co. Ltd) in this paper. The computed results show that the compression loads of the door seal are larger than the standard value of Shanghai Volkswagen Co. Ltd and the seal structure needs to be optimized. The computed results are proved by experiment."
Vehicle Door Latch Safety Measures Based on System Dynamics,"The governments of many countries have established regulations that address the issue of vehicle door safety during crash events. Depending on the regulation or specification, analytical tools may be acceptable for verifying the crashworthiness of a latching system. In those instances where actual test crashes are required for verification, analytical methods can still be used to help predict the outcome of a crash test. Two relevant analytical approaches for multibody dynamics computation are discussed in the paper. One is related to monitoring the effects of constant 30G inertia loading in all directions (spherical analysis) and another addresses inertia pulse loading of specified G levels in certain directions. In some crash situations, the latch system compliance with the regulations may be insufficient to prevent door release. To secure the door in the latched position additional safety devices can be deployed in various locations of the door latch system. One group of such devices relies on using inertia catch levers triggered by specific acceleration of vehicle door. The development and tuning of the inertia catch devices is done by analytical means followed by latch system validation during crash tests."
Door Overbend - Design Synthesis & Analysis,"This paper describes the analytical methodology for calculating the overbend needed in the door design to counteract the non-linear seal forces acting on the door header. Overbend in the door design will allow the Original Equipment Manufacturer to achieve competitive above belt flushness and gap dimensional targets at static equilibrium of the door header and weatherstrip. This method combines two analytical models of the weatherstrip and the Door-In-White (DIW) to forecast the design overbend necessary to achieve good fit and finish. These models are: 1) Seal compression-load deflection (CLD) models for each angle of attack of the weatherstrip to the door 2) A nonlinear Finite Element Analysis (FEA) model of the trimmed DIW. Bringing these two elements together to model the static equilibrium deflection, this is developed, into overbend requirements. The design synthesis process to meet the overbend design criteria is demonstrated. This method improves product quality and reduces door fit warranty by producing a product design that comprehends the inherent deflection of seal loads on the door structure."
A Discussion on Interior Compartment Doors and Latches,"Interior compartment doors are required by Federal Motor Vehicle Safety Standard (FMVSS) 201, to stay closed during physical head impact testing, and when subjected to specific inertia loads. This paper defines interior compartment doors, and shows examples of several different latches designed to keep these doors closed. It also explores the details of the requirements that interior compartment doors and their latches must meet, including differing requirements from automobile manufacturers. It then shows the conventional static method a supplier uses to analyze a latch and door system. And, since static calculations can't always capture the complexities of a dynamic event, this paper also presents a case study of one particular latch and door system showing a way to simulate the forces experienced by a latch. The dynamic simulation is done using Finite Element Analysis and instrumentation of actual hardware in physical tests."
Simulation Methods for Door Module Design,"With the automotive industry moving towards higher durability targets, reduced product development cycle time, and lower design costs, the need for simulation has never been higher. This paper explains the use of simulation techniques in the design and development of door module. A step-by-step approach to simulate a door slam event is proposed. Fatigue life estimation using simulation results is also discussed. Finally, simulation benefits are illustrated with a simulation-test case study completed at ArvinMeritor that resulted in a fatigue life improvement of more than 50%. The scope of this paper is limited to simulation methods for door slam. Test methods to collect data for door slam simulation are not discussed."
An Experimental Investigation About Cable Efficiencies in Current Automotive Door Systems,"Based on experimental and analytical research, a design tool was developed to estimate engineering parameters for side door latch inside release cables, given a pre-determined operating range. This design tool accurately estimates the cable efficiency for a set of parameters, thus significantly reducing the design time for latch and cable related engineering issues. Through testing and data analysis, the study determined the relationship between performance factors such as cable efficiency and effort losses, and design factors such as cable type, routing and loading conditions. Experimental data was used to generate curve fit equations that predict the cable efficiency for side a door latch system level development."
Environmentally Friendly Door Sash Tape,"Coating black paint on the door sash of automobiles has been a separate process from the body coating. Recently, moany automotive manufacturers are switching this secondary coating process to adhesive tape technology for various advantages. These advantages include reduction of VOC (volatile organic carbon), rationalization of assembly process, cost reduction and so on. Since this application is considered a variation of exterior decal film, most of the commercially available products are currently based on PVC (Polyvinyl chloride) film. (See Photo 1.) The automotive industry has increasingly been sensitive to the use of PVC due to its potential environmental problems. One of the problems is that the product cannot be incinerated when disposed of since it generates hydrogen chloride gas, dioxin and other toxic chlorinated organic matters. Also, reportedly its plasticizer may act as an endocrine disruptor (also known as ‘an environmental hormone’) when dissolved in water. Nitto Denko has developed an environmentally friendly polyolefin door sash tape as an alternative to the PVC tape. By optimizing polymer chemistry and film composition, the new polyolefin door sash tape exhibits high dimension stability in physical properties for a wide range of temperatures. Also, proprietary surface conditioning of this film ensures resistance to long-term outdoor exposure. An acceleration test has proved that the product retains 93% of glossiness compared to that of initial, with colorimetric change (delta E*ab) of only +0.12, for six and half years equivalent of solar ray radiation. Also, we did not detect toxic gases when we performed incineration tests. Only water vapor, carbon mono-oxide and carbon dioxide were detected in the given detection limit. This test has clearly demonstrated that the product causes significantly lower environmental damage than that of PVC."
3D Audio Reproduction via Headrest Equipped with Loudspeakers—Investigations on Acoustical Design Criteria,"This paper focuses on the analysis and evaluation of acoustical design criteria to produce a plausible 3D sound field solely via headrest with integrated loudspeakers at the driver/passenger seats in the car cabin. Existing audio systems in cars utilize several distributed loudspeakers to support passengers with sound. Such configurations suffer from individual 3D audio information at each position. Therefore, we present a convincing minimal setup focusing sound solely at the passenger’s ears. The design itself plays a critical role for the optimal reproduction and control of a sound field for a specific 3D audio application. Moreover, the design facilitates the 3D audio reproduction of common channel-based, scene-based, and object-based audio formats. In addition, 3D audio reproduction enables to represent warnings regarding monitoring of the vehicle status (e.g.: seat belts, direction indicator, open doors, luggage compartment) in spatial accordance. Furthermore, individual sound zones enable superior in-car communication between seats regardless of the current driving situation. An often overlooked topic is the acoustical privacy of in-car systems towards the exterior especially during telephony which is also tackled by the presented design as a by-product. We present how the structural shape, the assembly and alignment of the loudspeakers affects the frequency response, the effective sound pressure levels at the passenger’s ears, the inter-aural crosstalk, and the crosstalk to other seats. We further show that person affects the sound field by movements and therefore can change the overall performance. Finally, we present our approach for 3D audio reproduction for the car cabin schematically."
CAE Support to Vehicle Audio Installation Issues,"Audio CAE is an emerging area of interest for vehicle OEMs. Questions regarding early stages of the vehicle design, like choosing the possible positions for speakers, deciding the installation details that can influence the visual design, and integration of the low frequency speakers with the body & closures structure, are of interest. Therefore, at VCC, the development of the CAE methodology for audio applications has been undertaken. The key to all CAE applications is the loudspeaker model made available in the vibro-acoustic software used within the company. Such a model has been developed, implemented and verified in different frequency ranges and different applications. The applications can be divided into the low frequency ones (concerning the installation of woofers and subwoofers), and the middle/high frequency ones (concerning the installation of midrange and tweeter speakers). In the case of the woofer, it is the interaction with the body vibration that is of interest. Hence, the loudspeaker has to be used in a full vibro-acoustic Trimmed Body model. For the higher frequencies (midrange & tweeter) the body can be treated as locally reacting, if not rigid. The examples of the verification of the speaker model versus test data for a woofer mounted in a car door will be shown, together with applications to woofer installation issues. Regarding high frequencies, examples will be shown of the comparison of different grille variants and the evaluation of the position of the speaker on the sound quality at the listeners’ positions. Future developments will be discussed."
Asian Consumers Challenging the NVH Performance of European Cars - Implications on the Product Development in the 2020ies,"Sales of SUV and luxury cars on the largest market of the world - China - are growing at a high rate. The highways in large cities like Beijing or Shanghai are increasingly populated with cars from all over the world like Japan, USA, Europe and Korea and even some refined domestic brands. More than 10 million rich people can afford those cars and are skilled drivers. This huge group of potential consumers is targeted by luxury brand OEMs and by startup companies. It has been understood that these people have a high expectation of comfort. The twistbeam rear axle was replaced by multilink, double clutch transmissions were improved by comfort-mode drive programs, interior trims raised to Western standard performance levels, tyres specially developed for comfort in China, localized insulation materials and packages engineered to a one vehicle class higher level. The European avant-garde is capable of such high levels of complete vehicle NVH performance, whereas premium brands often compromise NVH with respect to high vehicle dynamics performance and passive safety requirements. Furthermore, the preference of Chinese consumers by long vehicles as a symbol of status and flaunting their riches, can also be consider a challenge for NVH performance. A longer wheelbase will require stiffer body and chassis structure to keep the ride comfort and squeak & rattle performance - to be more developed later on in the paper. At the same time Asian cars from Korea or Japan are sometimes outperforming the Europeans in terms of comfort. In future and in combination with the next evolution level of electrification and driving assistance the acceptable level of NVH annoyance will be reduced to a radically low threshold. In order to overcome the gap between this new threshold and current performances adjustments in vehicle specifications and the process to achieve those need to be implemented. The main focus is on powertrain noise, ride comfort and vibrations, rolling noise and wind noises and the overall NVH quality impression, e.g. of the door closing sound. The paper points out, which technical specifications are imperative for a good consumer reception and describes the processes that are needed for target achievement."
Impact of Different Types of Glazing on Thermal Comfort of Vehicle Occupants,"Due to intense peak summer temperatures and sunny summers in tropical countries like India etc., achieving the required thermal comfort of car occupants without compromising on fuel efficiency is becoming increasingly challenging. The major source of heat load on vehicle is Solar Load. Therefore, a study has been conducted to evaluate the heat load on vehicle cabin due to solar radiations and its impact on vehicle air-conditioning system performance with various combinations of door glasses and windscreen. The glasses used for this study are classified as green, dark green, dark gray, standard PVB (Polyvinyl Butyral) windscreen and PVB windscreen having infrared cut particles. For each glass, part level evaluation was done to find out the percentage transmittance of light of different wavelengths and heat flux through each glass. To verify the effectiveness of each glass, vehicle level air-conditioning system performance test was done in All Weather Chassis Dyno Facility for each retrofitted vehicle. To eliminate the effect of manufacturing variance while evaluating each retrofitted vehicle, only door glasses and windscreen were changed in the same vehicle keeping all other testing conditions such as ambient temperature, incident solar radiations, humidity and vehicle running pattern the same. The performance of each retrofitted vehicle was evaluated on the basis of its-soaking temperature, soaking time, grill temperature, and nose level temperature. On comparing the results of each configuration, the best door glass and windscreen configuration is proposed to improve the thermal comfort of the vehicle occupants."
In-Situ Studies on the Effect of Solar Control Glazings on In-Cabin Thermal Environment in Hot and Humid Climatic Zones,"Thermal comfort in a passenger cabin is the basic necessity of an occupant, especially in hot and humid climatic conditions. It is known that the reflective glazing solutions provide better thermal comfort inside the cabin due to significant reflection of IR part of solar radiation. However, in hot and humid climatic zones like India, significant reduction in heat load can also be achieved through cost effective solar control absorbing glazings. Thus, the present work aims to study the effect of solar control absorbing glazings on in-cabin temperatures and its impact on thermal comfort of the occupants in tropical climates. A combination of glazing sets with a range of solar energy transmission and absorption values is considered for the study. Indoor soak and cool tests are performed on a sedan model with multiple sets of solar control absorbing glass combinations. A constant ambient temperature of 38°C and solar radiation of 1000W/m2 are maintained throughout the tests. Wind speed is simulated for a vehicle running speed of 45 kmph. Net heat gain inside the cabin as a combination of various inward and outward loads of radiation through glazing is investigated. Accumulated heat is measured in terms of temperatures for comparison of various glazing sets. Reductions in heat loads are compared with experimental data of non-absorbing and reflective glazing sets available in literature. Best suitable combinations for front and back windshields, front and back side doors for the chosen vehicle are discussed in view of total solar energy transmission through the glazings and occupants thermal comfort."
Evaluation of Laminated Side Window Glazing Coding and Rollover Ejection Mitigation Performance Using NASS-CDS,"Occupant ejection has been identified as a safety problem for decades, particularly in rollover crashes. While field accident studies have repeatedly demonstrated the effectiveness of seat belts in mitigating rollover ejection and injuries, the use of laminated glass in side window positions has been suggested as a means to mitigate occupant ejection. Limited data is available on the field performance of laminated glass in preventing ejection. This study utilized 1997-2015 NASS-CDS data to investigate the reliability of the glazing coding variables in the database and determine if any conclusions can be drawn regarding the effect of different side window glazing types on occupant ejection. An initial query was run for 1997-2016 model year vehicles involved in side impacts to evaluate glazing coding within NASS-CDS. Sixteen individual cases were identified where the first-row side window glass was coded as both laminated and as in-place and holed, out-of-place and not holed, out-of-place and holed, or disintegrated from impact. NASS-CDS case summaries and photographs were reviewed and compared against original equipment manufacturer (OEM) specifications for the involved vehicles. The results demonstrated that the presence of laminated side window glass was incorrectly coded in 11 out of the 16 cases. The coding definitions were revised to query NASS-CDS for vehicles known to be equipped with standard or optional laminated glass in the first-row side windows based upon sources including the National Auto Glass Specifications (NAGS) database and vehicle manufacturer information (e.g., sales brochures, press releases, and other specifications). The new definitions were used in conjunction with the 16 previously identified side impact cases and found to correctly differentiate between the cases with and without laminated first-row side window glazing. Based upon this revised coding strategy, another NASS-CDS query was run to evaluate glazing type as it relates to rollover crashes involving 1997-2016 model year vehicles to determine the rate and frequency of front seat occupant ejection by glass type. This query resulted in a weighted 2,785,988 front seat occupants involved in a rollover, of which only 0.5% (13,640) occupants were in vehicles equipped with standard laminated front door window glass. Using the weighted occupants counts, there were 193 completely ejected and 277 partially ejected front seat occupants in vehicles equipped with standard laminated front door window glass; these numbers were based on unweighted samples of 10 or fewer. The sample sizes were too small to draw any statistically significant conclusions regarding ejection rates in rollover as a function of glazing type. The results of this study indicate that NASS-CDS glazing coding alone is not appropriate to identify the presence of laminated glass in specific vehicle window portals. This study also demonstrates that the resulting sample of field accidents is too small to assess the effectiveness of laminated glass in reducing the incidence of occupant ejection. The revised coding strategy may, however, be expanded with newer data and may be used in other databases such as Fatality Analysis Reporting System (FARS). It should be noted that, given the increased implementation of side curtain airbags in the vehicle fleet, it may become increasingly difficult to assess any individual contribution of laminated glass to occupant containment versus ejection."
Evaluation of Functional Performance of Mechanism Using Multi Body Dynamics Simulation,"The functional performance of the mechanism plays a vital role in attracting customer concentration towards the product. It is the first interface for interaction with the customer. Hence it is important to evaluate the functional performance at the time of the design phase itself in order to eliminate the possibility of an increase in proto-builds. The functional performance of a mechanism comprises parameters like, a mechanism should perform its function for which it is designed, with minimum effort required and ease in functionality. Evaluation of such parameters at the design stage involves many assumptions and this brings chance variables in the methodology. In order to eliminate these assumptions, a methodology has been developed using the multi-body dynamics (MBD) model of mechanisms like gear shifting mechanism and cabin door outer handle mechanism. The effort and displacement required to drive the mechanism were evaluated and a correlation of about 90% with the practical testing results was obtained. The same methodology was utilized to quickly optimize the existing design and reduce the effort and displacement required to drive the mechanism through the virtual model itself."
An Analysis of the Effects of Ventilation on Burn Patterns Resulting from Passenger Compartment Interior Fires,"Vehicle fire investigators often use the existence of burn patterns, along with the amount and location of fire damage, to determine the fire origin and its cause. The purpose of this paper is to study the effects of ventilation location on the interior burn patterns and burn damage of passenger compartment fires. Four similar Ford Fusion vehicles were burned. The fire origin and first material ignited were the same for all four vehicles. In each test, a different door window was down for the duration of the burn test. Each vehicle was allowed to burn until the windshield, back glass, or another window, other than the window used for ventilation, failed, thus changing the ventilation pattern. At that point, the fire was extinguished. Temperatures were measured at various locations in the passenger compartment. Video recordings and still photography were collected at all phases of the study. Although the fire origin and source were known, the vehicle burn patterns were analyzed and conclusions drawn based on the post-fire evidence regarding: ability to determine a window was open during the fire, which window was open, the effect the open window had on burn patterns and burn damage, and the ability to determine the fire origin. Thermocouple readings were plotted and analyzed post-test to study temperature characteristics during the burn tests."
A Development and Evaluation of Optimal Fingerprint Authentication Algorithm in Vehicle Use Environment,"Hyundai Motor Company mass-produced the world's first fingerprint entry and start system. This paper is a study on the evaluation method to develop and verify the optimal fingerprint authentication algorithm for vehicle usage conditions. Currently, fingerprint sensors and algorithms in the IT industry have been developed for the electronic devices, and are not suitable for the harsh environment of the vehicle and the vehicle life cycle for more than 10 years. In order to optimize the fingerprint sensor and algorithm for the vehicle, this study consisted of 3way test methods. As a result, the fingerprint system could be optimized for the vehicle and the recognition rate and security could be optimized according to the sensor authentication level. Through this study, the door handle recognition rate was improved by 25% and the start button recognition rate by 10%, and the fingerprint entry and start system was mass-produced with security level that satisfies the immobilizer regulations."
Robustness Design to Avoid Noise on Exterior Handle System,"Squeak and rattle are two undesirable occurrences during component operation and during vehicle driving condition, resulting in one of the top complains from costumers. One common grievance could happen during the user exterior handle operation and during side door closing. The exterior handle system during the operation could generate a squeak between interface parts, if materials and geometric tolerances was not been carefully designed. Also, vibration generated during door closing effort, might generate squeak between parts since the reinforcement for exterior handle touches the outer sheet metal internally. For this reason several guidelines might be included to avoid potential noise condition for this system during vehicle lifetime as correct material reduce friction between parts, taking into consideration the geometric condition between parts. Plus, coupling system on handles two pieces should also be evaluated to avoid squeak during use. Not less important, if required anti-shock material system may be applied to eliminate a clash produced between parts during excessive vibration. It is extremely important to evaluate the environment that the vehicle will be exposed since the correct material application also depend on this factor. Design parameters as materials used to produce parts, dimension geometric data and a robust technique of attachment must be analyzed. Correct material selection and tools like Dimensional Variation Analysis may be taken to identify and optimize the design to avoid noise and minimize cost."
Coating on Striker: Low Coefficient of Friction to Avoid Creak Noise,"The unpleasant noise (creak) originated from latch-striker interaction, perceived mainly when the vehicle is submitted to uneven road conditions is generated by stick-slip phenomenon mainly due materials incompatibility of contact surfaces. Generally, eliminate this incompatibility is unfeasible due technical and/or economics constrains; this scenario makes it necessary to act in other fronts to neutralize the effects of that incompatibility. Reduce the coefficient of friction from one of contact surfaces is an alternative that can be easily applied at striker through a thin thickness coating with that property."
Practical Design Considerations for Lightweight Side Window Applications,"Automotive manufacturers are requiring lightweight materials, including glazing materials to improve vehicle fuel economy and meet government mandates. Taken as a group, the area of four side windows is comparable to that of a windshield, and, therefore, can offer significant weight reduction opportunities. As glass thickness is reduced, the acoustic and stiffness properties of the glazing change. Newer developmental interlayer materials have demonstrated the capability for overcoming the reduction in performance to maintain the properties of the original heavier constructions."
Modeling and Numerical Analysis of Automotive Aerodynamic Noise Generation and Transmission Considering Equivalent Nonlinear Sealing,"Aerodynamic noise transmits through automotive window, causing great adverse influence on comfortability and noise-vibration-harshness (NVH) performance. However, the complicated external turbulent air flow, as well as the internal metal-rubber nonlinear sealing constraint, makes the mechanism of aerodynamic noise generation and transmission very difficult. Regarding the complex exterior aerodynamics-induced load and nonlinear metal-rubber interaction and constraint, an efficient two-step numerical prediction method is presented in order to study the mechanism of its generation and transmission. The first step uses the commercial ANSYS-Fluent computational fluid dynamics (CFD) analysis based on the shear stress transport (SST) - turbulence kinetic energy (k) - the rate of dissipation of turbulence kinetic energy ε (epsilon) model and Lighthill’s noise source theory. For low Mach number and high Reynolds number flow like the flow around a vehicle body, dipole source is regarded as the dominant contribution and can be obtained by the broadband noise source model. Exterior turbulent flow field of a full-scale automotive is established and near-field sound power distribution of automotive window has been obtained, which are both subsequently input to the acoustic model to investigate the noise generation mechanism. The second step consists of the numerical prediction of noise transmission through automotive window. Nonlinear spring-based surrogate model for seal nonlinear constraint is proposed and verified by modal experiment. Based on SAE J1400 reverberant-anechoic measurement standard, a numerical prediction model of the sound transmission loss (STL) is constructed using commercial vibro-acoustic solver Actran. New automotive window structural design by non-uniform density distribution is proposed to optimize the STL property. The present methodology of STL modeling and numerical prediction provides valuable instructions for performance optimization of automotive door under high speed driving condition."
“Taguchi Customer Loss Function” Based Functional Requirements,"Understanding customer expectations is critical to satisfying customers. Holding customer clinics is one approach to set winning targets for the engineering functional measures to drive customer satisfaction. In these clinics, customers are asked to operate and interact with vehicle systems or subsystems such as doors, lift gates, shifters, and seat adjusters, and then rate their experience. From this customer evaluation data, engineers can create customer loss or preference functions. These functions let engineers set appropriate targets by balancing risks and benefits. Statistical methods such as cumulative customer loss function are regularly applied for such analyses. In this paper, a new approach based on the Taguchi method is proposed and developed. It is referred to as Taguchi Customer Loss Function (TCLF). The “Taguchi Quality Loss Function (TQLF)” methodology has been used primarily to improve quality from a manufacturing standpoint, giving engineers a way to understand how process variation affects customer satisfaction. In the proposed “Taguchi Customer Loss Function (TCLF)” methodology, a similar analogy is applied for developing requirements on the design such that variation in customer preference is accounted for. Also, trade-offs can be made with other business constraints while keeping the customer dissatisfaction to minimum. Example problems are presented to demonstrate its simplicity and its potential for understanding customer clinic data."
Eleven Instrumented Motorcycle Crash Tests and Development of Updated Motorcycle Impact-Speed Equations,"Eleven instrumented crash tests were performed as part of the 2016 World Reconstruction Exposition (WREX2016), using seven Harley-Davidson motorcycles and three automobiles. For all tests, the automobile was stationary while the motorcycle was delivered into the vehicle, while upright with tires rolling, at varying speeds. Seven tests were performed at speeds between 30 and 46 mph while four low-speed tests were performed to establish the onset of permanent motorcycle deformation. Data from these tests, and other published testing, was analyzed using available models to determine their accuracy when predicting the impact speed of Harley-Davidson motorcycles. The most accurate model was the Modified Eubanks set of equations introduced in 2009, producing errors with an average of 0.4 mph and a standard deviation (SD) of 4.8 mph. An updated set of Eubanks-style equations were developed adding data published since 2009, and advancing from two equations (pillars/axles and doors/fenders) to four equations (axles, pillars/bumpers, doors, and fenders). When applied to the subject tests, the newly developed set of equations produced an average error of 3.5 mph (SD = 4.3 mph). With respect to all available data (N = 99), the equations produced an average error of 0.1 mph and a standard deviation of 5.8 mph. The errors were also analyzed for each of the four equations developed here, and confidence intervals offered. This research, which represents the first detailed analysis of Harley-Davidson motorcycles’ collision response, indicates they behave in a manner similar to previously tested motorcycles. Further, the equations developed and presented here give accident investigators a refined method for estimating the impact speed of an upright motorcycle, Harley-Davidson or otherwise, having struck an automobile with its front tire."
Regression Analysis: A Geometric Perspective,"Regression analysis is perhaps one of the most widely used statistical tools in six-sigma projects. The reason for its popularity is that it provides a formal evaluation of the relationship between one dependent variable and one or more predictors. The ordinary least squares (OLS), which is a method for estimating the parameters of the linear regression model, has some numerical properties that can be easily understood by looking at them in a geometric manner. In this paper, we discuss the fundamentals of both simple and multiple regression analysis from a geometric perspective. This approach offers an intuitive understanding of some concepts that otherwise would require a background in statistical mathematics and differential calculus. One of the topics covered in this paper is multicollinearity, whose consequences are not well understood by many practitioners. A practical example drawn from the automotive industry (body exterior quality) is used to clarify the basic notions that appear throughout the paper. This example consists of a regression analysis made over a sample of vehicles in an attempt to explain the level of customer's complaints regarding side door closing effort (dependent variable) by the actual closing effort measured in a laboratory using a standard procedure (independent variable). It is well known that closing effort, in turn, is also highly correlated with the compression load deflection (CLD) of the door seals, meaning that including both variables as predictors in the same model would produce unreliable estimates of the parameters. Unfortunately, many quality engineers disregard the effects of multicollinearity when they perform this kind of analysis. This paper is intended to draw attention to these issues in a user-friendly way."
Standard for Safety Glazing Materials for Glazing Motor Vehicles and Motor Vehicle Equipment Operating on Land Highways - Safety Standard,"Specifications, test methods, and usage provisions for safety glazing materials used for glazing of motor vehicles and motor vehicle equipment operating on land highways."
Automotive Safety Glazing Materials,"This SAE Recommended Practice is a guidance document, which covers current safety glazing materials applicable for use in motor vehicles and motor vehicle equipment. Nominal specifications for thickness, flatness, curvature, size, and fabrication details are included. This guidance document does not precede or replace customer specifications and requirements."
Automotive Safety Glazing Materials,"This SAE Recommended Practice is intended to cover current safety glazing practice applicable to safety glazing for use in motor vehicles and motor vehicle equipment. Nominal specifications for thickness, flatness, curvature, size, and fabrication details are included principally for the guidance of body engineers and designers."
Analysis of Damage Caused to Vehicle Body Panels by Impacting Hail and Various Tools and Objects,"On the 25th December 2011 there was a hail storm in the state of Victoria, Australia, which caused approximately AU$712 million worth of damage. Some of this damage was caused to passenger vehicles. The authors conducted a number of inspections of hail-damaged vehicles as a result of insurance claims being disputed or rejected on the basis that some, or all, of the alleged hail damage was not created by hail but instead created intentionally by the vehicles' owners with the use of different tools and/or objects. As a result of the inspections and investigations of potentially fraudulent claims, the authors conducted a total of 119 tests designed to replicate damage caused to vehicle body panels by impacting hail and to recreate claimed hail damage by using tools and other objects. To do so, the authors created two sizes of hail: Ø20 mm and Ø40 mm hail. A total of 15 impact tests were conducted with Ø20 mm hail. The impact speed for the Ø20 mm hail varied between 75 km/h and 144 km/h, with the average being 113 km/h. A total of 50 impact tests were conducted with Ø40 mm hail. The impact speed for the Ø40 mm hail varied between 66 km/h and 133 km/h, with the average being 101 km/h. The testing impact speeds were generally higher than the terminal velocities of the corresponding hail, so the damage observed is expected to be an over estimation of the actual damage caused by hail. The hail was projected at the test vehicle using a purpose-built projectile launching device that used a sling-like mechanism to project hail in a horizontal direction at a test vehicle. The test vehicle was a white-colored 2001 model Holden Commodore with non-metallic paint. The body panels tested were: bonnet, roof, boot, all four doors, the vehicle pillars and cant rail. High speed cameras were used to determine the impact speed of the hail. Damage was photographed and recorded. In addition to impacting the vehicle with hail, a number of different tools and objects were used to recreate man-made damage. Tools and objects used were: claw hammer (conventional), welding hammer, ball-peen hammer, mason hammer, lead ball sink in a sock, golf ball in a sock, ratchet, breaker bar, crowbar and center punch. The conducted tests revealed the following findings: 1. hail impacting the vehicle body panels will not scratch or mark the paint but the paint may chip if hail impacts the vehicle near a fold or edge of a panel; 2. dents caused by hail will cause the light to move smoothly and continuously across the dent and the light will not ""break"" or crease; 3. where dents were caused by tools and objects the light will crease into multiple (two or more) distinct areas as it passes over the dent; 4. scratches and/or markings in the paint were identified on dents caused by tools and objects; 5. folds and curves on the panels did not affect the size of the dent caused to the panel; using the same tool and force to impact two different body panels (A-pillar and roof) resulted in dents that were very similar in physical appearance; 6. for the same impact speed the larger Ø40 mm hail caused more damage than the Ø20 mm hail; and 7. for the same size hail the higher impact speed hail caused more damage."
Eleven Instrumented Motorcycle Crash Tests and Development of Updated Motorcycle Impact-Speed Equations,"Eleven instrumented crash tests were performed as part of the 2016 World Reconstruction Exposition (WREX2016), using seven Harley-Davidson motorcycles and three automobiles. For all tests, the automobile was stationary while the motorcycle was delivered into the vehicle, while upright with tires rolling, at varying speeds. Seven tests were performed at speeds between 30 and 46 mph while four low-speed tests were performed to establish the onset of permanent motorcycle deformation. Data from these tests, and other published testing, was analyzed using previously published equations to determine their accuracy when predicting the impact speed of Harley-Davidson motorcycles. The most accurate model was the Modified Eubanks set of equations introduced in 2009, producing errors with an average of 0.4 mph and a standard deviation (SD) of 4.8 mph. An updated set of Eubanks-style equations were developed adding data published since 2009, and further partitioning from two equations (pillars/axles and doors/fenders) to four equations (axles, pillars/bumpers, doors, and fenders). When applied to the subject tests, the newly developed set of equations produced an average error of 3.5 mph (SD = 4.3 mph). With respect to all available data (N = 99), the equations produced an average error of 0.1 mph and an SD of 5.8 mph. The errors were also analyzed for each of the four equations developed here, and confidence intervals offered. This research, which represents the first detailed analysis of Harley-Davidson motorcycles’ collision response, indicates they behave in a manner similar to previously tested motorcycles. Further, the equations developed and presented here give accident investigators a refined method for estimating the impact speed of an upright motorcycle, Harley-Davidson or otherwise, having struck an automobile with its front tire."
Prediction of Sound Transmission through Door Seals Using the Hybrid FE-SEA Method,"During the last decades, the application of noise control treatments in vehicles has targeted the main noise transmission paths to interior noise. These paths include vehicle body panels such as dash panel, doors and floor. Many improvements have been achieved on these areas, and, as a consequence, other transmission paths once thought as secondary became relevant. This is the case of the sound transmission through door seals and others sealing elements at mid and high frequencies. In this paper, the interest lies on the prediction of the transmission loss of door seals. A full nonlinear deformation/contact analysis is used to estimate the deformed geometry of a door seal in real conditions. The geometry is then used in a vibro-acoustic analysis to predict the in-situ transmission loss of the seal using a local Hybrid FE-SEA model. The channel between the door and the car structure where the seal is located is also included in the analysis. Results for the transmission loss are compared with experimental data, showing a good correlation. It is also shown that the channel is an important element of the analysis and must be taken into account."
Innovative Robust Solutions for Lean Manufacturing in Automotive Assembly Processes,"The article presents an innovative approach to the implementation of a robust design optimization solution in an automobiles assembly process. The approach of the entire project is specific to the 6 Sigma optimization process, by applying the DMAIC cycle integrated in a robust engineering approach for rendering lean the final product assembly process. According to the improvement cycle, the aspects specific for such a process are presented sequentially starting with the “Define” phase for presenting the encountered problem and continuing with the presentation of the scope of the project and its objectives. The “Improvement” cycle phase is applied by the analysis of the monitored 6 Sigma metrics (defined during the previous “Measure” phase and the cause and effect analysis, done during a brainstorming meeting developed during the “Analyze” phase). There follows a proposal for the innovative robust solution by which the assembly process is optimized. Therefore, we propose the final assembly of already painted doors on the already assembled cars with a special work-holding which is easy to handle by the human operator. The automation of designed and implemented solutions provides features of error proofing for the assembly process in the case in which the doors are not located accordingly on the work-holding locating elements, which may lead to various inconveniences during the assembly on the vehicle and/or some faults of the door quality, such as scratches or deformations because of the impacts. The initially presented process indices, for the not yet optimized process are finally evaluated after the implementation of the innovative solution for a comparative study of the initial monitoring results and after the implementation of the proposed corrective solution. This underlines the critical conclusions that are induced during the “Control” phase. The final conclusions point to the corrective / preventive actions for a sustainable and reliable optimization, which give the maximal process its overall efficiency."
Advances in Vehicular Ad-Hoc Networks: Developments and Challenges,"A Vehicular Ad Hoc Network (VANET) is a non-infrastructure based network that does not rely on a central administration for communication between vehicles. The flexibility of VANETs opens the door to a myriad of applications; however, there are also a number of computer communication challenges that await researchers and engineers who are serious about their implementation and deployment. This book tackles the prevalent research challenges that hinder a fully deployable vehicular network. This unique reference presents a unified treatment of the various aspects of VANETs and is essential for not only university professors, but also for researchers working in the automobile industry. Topics include: Architecture of vehicular ad hoc networks Communication technologies in vehicular applications Cooperative collision avoidance Geographic routing in vehicular ad hoc networks IEEE 802.11g and IEEE 802.16e technologies Information sharing in VANETs Infrastructures in vehicular communications Mobility and traffic model analysis Opportunistic networking Routing protocols in vehicular ad hoc networks"
Kiekert unveils automatic-door tech for autonomous vehicles,"A new electronic side door latch is the prelude to vehicle side doors that automatically open and close on command. “Our endgame is about providing a system in which the side doors automatically open when an autonomously-driven car arrives for passengers,” said Hector Verde, Director of Product Development for the Americas at Kiekert. Those doors would also close automatically after the occupants are in the vehicle. All this could happen with just the push of a button or sensor recognition, he added."
Researchers Uncover New Way to Control Information by Mixing Light and Sound,"A Yale lab has developed a new, radio frequency processing device that allows information to be controlled more effectively, opening the door to a new generation of signal processing on microchips."
Lightweight door module aims to trim vehicle weight,"A new ultralight door architecture nets a 42.5% weight savings compared to a current production door-and that's enough to put this lightweight concept in an enviable position. “This lightweight door module has a great opportunity to be commercialized. It's not just high-tech. It's also at the right cost,” said Reuben Sarkar, Deputy Assistant Secretary for Transportation, Energy Efficiency and Renewable Energy at the U.S. Department of Energy."
Automobile and Motor Coach Wiring,"This SAE Recommended Practice covers the application of primary wiring distribution system harnesses to automotive, and Motor Coach vehicles. This is written principally for new vehicles but is also applicable to rewiring and service. It covers the areas of performance, operating integrity, efficiency, economy, uniformity, facility of manufacturing and service. This practice applies to wiring systems of less than 50 V."
Passengers First Light Truck - A Modern Take on a Narrow Wake,"Individuals in the United States consume twice as much energy as those in any other region. Solitary workday commutes in light vehicles are the leading reason for this difference. An electric vehicle design is proposed to help catalyze more social, higher occupancy, commuting habits - through application of existing technology. Performance criteria are: 1) attract passengers to the suburban front yard at 6:30 AM, 2) match market leading crash test performance, cargo capability, and sense of freedom, and 3) deliver easier parking, better acoustics and better passenger mile efficiency. A vehicle as a rolling event venue determines a large windscreen, side-by-side upright seating arrangements, and acoustic excellence -an experience where there are only good seats. These requirements force a decision to close the wake along a vertical line to form a narrow wake. The chassis is platform batteries with dual motor electric rear drive and undetermined front drive. Findings: 1 Narrow wake synergies include: a) cargo loading on a tailgate ramp to a low 0.3m (12 inch) high load floor through a 0.8m (32 inch) wide opening - as a controlled event using an onboard powered trolley, b) passengers more safely located, and c) thick rear doors that pivot concentric with the rear axle, with no chance of damaging adjacent objects. 2 A consistent driver’s eye location, as datum, provides better forward visibility past the A-Pillar and more consistent relationships between driver, passengers and vehicle safety and content delivery systems, when compared to location off fixed pedals at the firewall. 3 Collateral benefits of the eye datum include large section B-Pillars, dual diagonal cooling circuits that apply full cooling power as the sun clocks, and a smooth transition to self-driving operation."
Intrusion Resistance of Safety Glazing Systems for Road Vehicles,"This SAE Recommended Practice specifies an intrusion resistance test method for glazing systems installed in motor vehicles. Intrusion resistance performance is determined not solely by the glazing but also by the glazing attachment to the vehicle and by the vehicle structure. Therefore, the glazing/attachment/vehicle structure must be tested as a single unit. This test determines intrusion resistance only. The test applies to those materials that meet the requirements for use as safety glazing materials as specified in ANSI/SAE Z26.1 or other applicable standards. The test applies to all installation locations."
A Test Method and Simulation Study of PMMA Glazing on Motion Deviation,"For achieving vehicle light weighting, the motion deviation is calculated for substitution of PMMA glazing for inorganic glass. In this paper, a test method is proposed to measure and calculate the motion deviation of the dual-curvature glass. To simulate the dual-curvature glass, the torus surface is fitted with least square method according to the window frame data, which are measured by Coordinate Measuring Machine. By using this method, the motion deviation of PMMA glazing and inorganic glass can be calculated, which can not only validate the effectiveness of motion simulation, but also compare the performances. The results demonstrate that the performance of PMMA glazing is better than that of inorganic glass and the simulation results is validated."
Framed Door x Fully Stamped Door,"When designing a new subsystem for a new vehicle platform, technical requirements, performance targets and cost implications drive the decision process towards which concept to be adopted. If this platform is planned for worldwide introduction, local requirements and capabilities have to be put into the business equation. Among the possible design options for a Side Door Subsystem, including basically Inset doors and Limo doors with their variations, the best for the market is selected on: Commonality requirements through the platform family; Technical implications of each design concept; Technical excellence to produce parts with the required quality/cost in the local market; Costs and timing associated with each design concept; Benchmarking. This composition of factors drove the decision to adopt different design options for South America and Europe on the recently launched small car platform. This paper demonstrates the rationale of this decision making process and the positive outcomes of it."
Average Vehicle Dimensions for Use in Designing Docking Facilities for Motor Vehicles,This SAE Recommended Practice establishes limits for empty vehicle floor heights and provides limits of vehicle dimensions for use in designing docking facilities for motor vehicles.
Leading Edge Requirements Engineering for the Automotive Industry - With the Use of JAMA,"There have been many publications about requirements management, and still organizations are struggling to show 100% coverage and traceability in a lean way. It does not start with CMMI nor SPICE. It does not end with tools like DOORs, Polarion, Codebeamer or JAMA. It does depend on the right setup and how it feels in the everyday life of an engineer. This paper defines and explains what it takes to establish leading edge requirements engineering for the automotive industry. It describes how work day integration of requirements engineering and management can be achieved. The different roles in engineering are addressed with their unique needs to support them. One 120% RQM data model is shown and explained. The necessary rollout project is designed with activities to adapt a tool to existing processes and individual tools, explain, improve, transfer as well as train/coach the engineers. The impact of and resolution for existing bypasses is discussed as well as the necessary qualification of rollout coaches. Before going in bit and byte - let’s not forget to get Product Management on board. Usability is a key for product success, so why should it be different for the tool success. Here we show how a tool need to adapt, not just to the different engineering roles but also to the interfaces of management and the rest of the tool landscape. In efficiency in use of roots in hesitation and fear of the engineers. Simple concepts are explained to introduce a creative fail-forward culture around requirements engineering. Chicken-or-Egg discussions are bypassed with a creative distinction or requirements versus specification. The activities around requirements are explained in a complete requirements lifecycle model. Necessary design levels and all RQM items are shown in and exemplary tool setup in JAMA Connect. A test driven bottom up approach is added for special use-cases. Finally it is shown how we can reduce surprises ate product release significantly with 100% traceability and integrated change management. The difference of coverage and traceability if shown and explained and how to use it to lift the readers requirements management in the 21st century. As part of the outlook, the challenge of configuration management is addresses as a problem that today is still not sufficiently supported by most requirements management tools.."
Experimental noise and vibration analysis in an aircraft simplified hydraulic systems,"Due to the great use of airplanes for transportation, it was necessary some studies to improve it, one of the most difficult problems to solve, is the noise generated by the systems. In-flight sound pressure levels can sometimes be intense and cause fatigue to the cabin crew, communication failures and discomfort to the passengers. This is often caused by the turbulent boundary layer over the aircraft body, engine noise and vibration and internal aircraft systems. The aircraft hydraulic system is responsible for moving the rudder, aileron, brakes, main door, and other components, and consequently, the noise of this system became more noticeable. This system comprises a pump, generally, located at the back of the aircraft and pipes, which are fixed along the fuselage. The pipes are connected to the fuselage using rubber mounts. Analyzing experimental measurements is possible to identify that hydraulic system contribute to the in-flight sound pressure level in the aircraft cabin. However is the connection between pipe and fuselage the main problem. In this paper, will be demonstrated a simplified methodology to analyze these noise, generated by the hydraulic system, with results of sound pressure and vibration measured in an experimental device, operated under different conditions."
"Ultra-Thin, Energy-Efficient Photodetector Integrated with Gorilla Glass","Photodetectors — also known as photosensors — contribute to the convenience of modern life. They convert light energy into electrical signals to complete tasks such as opening automatic sliding doors and automatically adjusting a cellphone’s screen brightness in different lighting conditions. Researchers are advancing photodetectors’ use by integrating the technology with durable Gorilla glass, the material used for smartphone screens that is manufactured by Corning Incorporated."
Simulating the Static and Dynamic Response of an Automotive Weatherstrip Component,"Understanding the resonant behavior of vehicle closures such as doors, hoods, trunks, and rear lift gates can be critical to achieve structure-borne noise, vibration, and harshness (NVH) performance requirements, particularly below 100Hz. Nearly all closure systems have elastomer weatherstrip components that create a viscoelastic boundary condition along a continuous line around its perimeter and is capable of influencing the resonant behavior of the closure system. This paper outlines an approach to simulate the static and dynamic characteristics of a closed-cell Ethylene Propylene Diene Monomer (EPDM) foam rubber weatherstrip component that is first subjected to a large-strain quasi-static preload with a small-strain sinusoidal dynamic load superimposed. An outline of a theoretical approach using “phi-functions” as developed by K.N. Morman Jr., and J.C. Nagtegaal [1] is introduced followed by a discussion of the material characterization that was done to construct a suitable elastomer material model for finite element analysis (FEA). Next, to validate the approach, the FEA and correlation of a simple extension specimen is presented followed by the analysis and correlation of a weatherstrip component with a complex cross sectional shape. It is observed that the static and/or dynamic response of the weatherstrip material and component can be dependent on several factors such as excitation frequency, large-strain preload, vibration amplitude, component geometry, and friction. Correlation between simulation and experimental results for dynamic stiffness and loss factor are in general agreement below 100Hz."
Application of the Hybrid FE-SEA Method to Predict Sound Transmission Through Complex Sealing Systems,"Currently, the use of numerical and analytical tools during a vehicle development is extensive in the automotive industry. This assures that the required performance levels can be achieved from the early stages of development. However, there are some aspects of the vibro-acoustic performance of a vehicle that are rarely assessed through numerical or analytical analysis. An example is the modeling of sound transmission through vehicle sealing systems. In this case, most of the investigations have been done experimentally, and the analytical models available are not sufficiently accurate. In this paper, the modeling of the sound transmission through a vehicle door seal is presented. The study is an extension of a previous work in which the applicability of the Hybrid FE-SEA method was demonstrated for predicting the TL of sealing elements. A numerical validation of simplified Hybrid FE-SEA model is performed, which is followed by the application of the method to the TL of a car door seal. A full non-linear deformation/contact analysis is used to estimate the deformed geometry of the door seal in real conditions. The geometry is then used in a vibro-acoustic analysis to predict the in-situ transmission loss of the seal using a local Hybrid FE-SEA model. The channel between the door and the car structure where the seal is located is also included in the analysis. Results for the transmission loss are compared with experimental data, showing a good correlation."
A Computational Process for Early Stage Assessment of Automotive Buffeting and Wind Noise,"A computational process for early stage vehicle shape assessment for automotive front window buffeting and greenhouse wind noise is presented. It is a challenging problem in an experimental process as the vehicle geometry is not always finalized. For example, the buffeting behavior typically worsens during the vehicle development process as the vehicle gets tighter, leading to expensive late counter measures. We present a solution using previously validated CFD/CAA software based on the Lattice Boltzmann Method (LBM). A CAD model with realistic automotive geometry was chosen to simultaneously study the potential of different side mirror geometries to influence the front window buffeting and greenhouse wind noise phenomena. A glass mounted mirror and a door mounted mirror were used for this comparative study. Interior noise is investigated for the two phenomena studied. The unsteady flow is visualized and changes in the buffeting and wind noise behavior are explored."
Boundary Condition Effect on the Correlation of an Acoustic Finite Element Passenger Compartment Model,"Three different acoustic finite element models of an automobile passenger compartment are developed and experimentally assessed. The three different models are a traditional model, an improved model, and an optimized model. The traditional model represents the passenger and trunk compartment cavities and the coupling between them through the rear seat cavity. The improved model includes traditional acoustic models of the passenger and trunk compartments, as well as equivalent-acoustic finite element models of the front and rear seats, parcel shelf, door volumes, instrument panel, and trunk wheel well volume. An optimized version of the improved acoustic model is developed by modifying the equivalent-acoustic properties. Modal analysis tests of a vehicle were conducted using loudspeaker excitation to identify the compartment cavity modes and sound pressure response to 500 Hz to assess the accuracy of the acoustic models. The optimized acoustic model is also coupled with a structural finite-element model of the trimmed body to evaluate the effect of body panel flexibility on the interior sound pressure response. The optimized acoustic model is found to exhibit the best correlation in terms of the predicted sound pressure FRF response at the passenger compartment interior locations and at the compartment boundary surfaces."
Evaluation of the Aerodynamic and Aeroacoustic Response of a Vehicle to Transient Flow Conditions,"A vehicle on the road encounters an unsteady flow due to turbulence in the natural wind, unsteady wakes of other vehicles and as a result of traversing through the stationary wakes of roadside obstacles. Unsteady effects occurring in the sideglass region of a vehicle are particularly relevant to wind noise. This is a region close to the driver and dominated by separated flow structures from the A-pillar and door mirrors, which are sensitive to unsteadiness in the onset flow. Since the sideglass region is of particular aeroacoustic importance, the paper seeks to determine what impact these unsteady effects have on the sources of aeroacoustic noise as measured inside the passenger compartment, in addition to the flow structures in this region. Data presented were obtained during on-road measurement campaigns using two instrumented vehicles, as well as from aeroacoustic wind tunnel tests. Conventional admittance functions relating oncoming flow yaw angle to cabin noise response are generally not suitable due to the non-linear steady state characteristics obtained in the wind tunnel, i.e. the cabin noise does not vary with yaw angle in a linear fashion under steady-state conditions. Therefore two alternative approaches were used based on instantaneous conditions to determine a quasi-steady predicted cabin noise time-history. These techniques demonstrated that the cabin noise response to oncoming flow unsteadiness remained generally quasi-steady up to fluctuation frequencies of approximately 2 to 5 Hz, where above this smaller flow scales have a progressively smaller impact on cabin noise fluctuations. Therefore, with a measurement of both the cabin noise in the steady environment of the wind tunnel and the unsteady onset flow conditions, the fluctuations (and thus the modulation) of the wind noise under these unsteady conditions is able to be predicted."
Investigation of Squeak and Rattle Problems in Vehicle Components by Using Simulation & Doe Techniques,"The automotive and related industries are concentrating their efforts on improving comfort by lowering engine, wind, and road noise and vibrations. However, as background noise levels decrease, the squeaks and rattles (S & R) generated by the vehicle's many components become more noticeable and distracting. As a result of the absence of a dominant noise source from a traditional petrol/diesel car, (S & R) noise becomes more dominant than other types of noise in electric vehicles. In this paper, we propose a novel simulation technique for developing a systematic approach to identifying and solving (S & R) problems in vehicle components/sub-assemblies during the primary stage of product development cycle, thus reducing the overall product development time. This paper will present a novel approach to comprehending various methods and Design of Experiments (DOE) techniques used to determine the root cause of (S&R) problems and to solve those using numerical methods."
Axiomatic Design of the Check Link for an Automotive Side Closure System,"In the automotive industry, a lot of attention has been paid to the effort required for opening/closing the doors, and for a good reason. The door closing and opening effort creates an impression in the customer’s mind about the engineering and quality of the vehicle even before he or she enters it. Although this seems trivial compared to the complexity of the rest of the automobile, effective engineering of the door opening/closing effort is challenging due to the interaction of several design parameters. Some of the best practices focus on satisfying targets for the energy required shutting the door from a small open position (around 10 degrees). However this practice ignores the complete closing/opening motion of the door from a full open position. In this paper Axiomatic Design principles were used to obtain a better understanding of the door opening/closing motion from a full open position, in terms of the functional requirements (FR), and how these requirements are satisfied by the various design parameters (DP) of the door closure system. In this paper we present an analysis of the opening/closing efforts of the side door closure system using this Axiomatic Design approach, and a discussion on the design of the check-link. The complete opening/closing motion is a result of the interaction of the different components of the door closing system, such as the latch, weather seal, energy loss due to air-binding effect, the inclination of the hinge axes, and the check-link. FR/DP decomposition of the Door System is presented. This provides the framework for creative design solutions."
Development and Validation of Utility Matrix for Automotive Interiors in Real World Usage,"As the real world usage profile of customers is becoming increasingly dynamic the need for more utility features in interior parts of vehicle has increased. The main purpose of the study is to analyze how the changing customer style actually influences the volume requirement of the utility spaces i.e. at the glove box, console door pocket etc. In the present study, an exhaustive list of utilities, and a utility matrix based on the user characteristics for automotive interiors is developed. Based on customer reviews on the web and expert opinions, seven user profiles were defined. The selection matrix is arrived at by using the usability index, accessibility index and the disbursement index. The matrix is evaluated using statistical methods and validated for real world usage. The selection matrix is used to identify relatively important utility features and preferred locations in automotive interior parts."
Secondary Control Modifications,"This SAE Recommended Practice establishes a uniform procedure for assuring the manufactured quality, installed utility and performance of automotive products to the relocation, alteration, replacement and/or extension of secondary controls and systems other than those provided by the vehicle manufacturer (OEM). These products are intended to provide driving capability to persons with physical disabilities. These products function as adaptive modifications to compensate for lost or reduced function in the extremities of the driver. These include, but are not limited to the following: Cruise Control; Door Locks; Gear Selector; Hazard Flasher; Headlight Beam Selector; Heater/Vent/Air Conditioner (HVAC); Horn; Ignition/Starter; Light controls; Mirrors; Parking Brake; Power Seats; Turn Signals; Power Window Controls; and Windshield Wiper/Washer and defogger; Rear Accessories (Defogger, Wiper/Washer). The purpose of any secondary control adaptation is to provide the effective use of the motor vehicle operating systems to a driver with a disability, so that he or she may drive and operate that motor vehicle with the same degree of safety as a non-disabled driver. Thus, the adaptive equipment must be (1) accessible to the driver with a disability for whom it is designed, (2) not susceptible to inadvertent operation which may be inconvenient or dangerous for the driver and other users of the roadway, and (3) suitable by non-disabled drivers who may have a need to operate the motor vehicle whenever possible. For purpose of this document, the secondary controls listed previously have been classified according to the following protocols. The categorization of these controls, while different from other SAE publications, is reflective of the manner in which driver rehabilitation specialists determine appropriate vehicle modifications. These categories are arranged to assign priorities that allow the user to operate a vehicle in the most efficient manner possible. Mode A - These controls shall be operable by the driver while the vehicle is in operating mode. They must be accessible to the driver for which they were intended while being able to maintain control of the vehicle steering, brake and accelerator functions. Included in this group are: Cruise control “Set;” Headlight Beam Selector; Horn; Turn Signals; and, Windshield Washer/Momentary Wipe. Mode B - These controls shall be operable by the driver while maintaining control of the vehicle brake function with the vehicle not in motion, as in the case of vehicle start-up or re-start necessitated by engine stall. Included in this group are: Gear Selector and Ignition/Starter. Mode C - These controls shall be at least operable by the driver when the vehicle is stationary, either temporarily or parked. Included in this group are: Cruise control “On” and “Off;” Door Locks; Hazard Flashers; Heater/Vent/Air Conditioner (HVAC); Light Controls; Mirrors; Parking Brake; Power Seats; Windshield Wiper; and Power Window Controls; Rear Accessories (Defogger, Wiper/Washer)."
A Study on the Methodology for Improving IQS Score for Door Opening/Closing Effort,"IQS score (hard to open/close) is a major factor in determining automotive door closing performance. There are several functions that automotive side doors must fulfill: isolation from snow/ rain/ noise/ dust/ high temperature, wind noise, and opening/closing functions. This paper focuses on side door Opening/Closing, which is not only the primary function but also the first operation that all customers experience when car shopping. As the subjective demands of customers have increased and their level of sophistication has grown, the ergonomics of automotive side door functions has become a critical issue for both designer and customer. The side door area does not generally have specifications because door operability totally relies on each customer's senses and there are no parameters to be measured by test/experimental devices. So the IQS score could become the standard for evaluating a door's difficulty of opening and closing. The objective of this work is 1)to develop a correlation between subjective evaluation, some test results and IQS score (hard to open/close) and 2)to find ways to improve IQS score (hard to open/close) by reducing the minimum closing velocity."
Study of Minimum Door Closing Speed Analysis Method,"The minimum door closing speed is an important target in vehicle door design. Engineers need a proper method to evaluate the door closing speed during the design phase. Analytical approaches are presented to solve the difficult issues in analyzing the minimum door closing speed. First, the weather strip is simplified into a discrete model with several spring elements. This method does not need to use 3-D contact analysis for the weather strip and can save computing time with acceptable accuracy. Second, the minimum closing speed is solved by using the energy equation which needs one iteration only. The method has high efficiency and can be used to evaluate the door closing speed effectively during the design phase."
Door Check Load Durability - Fatigue Life Prediction,"This paper describes an analytical methodology for predicting the fatigue life of a door system for check load durability cycles. A check stop load durability cycle occurs when a customer opens the door beyond the door detent position with a force applied on the check link or hinge check stops. This method combines Finite Element Analysis (FEA) model and fatigue code to compute the durability requirements. The FEA model consists of Door-in-White (DIW) on body with integrated hinge check link or independent check link. Nonlinear material, geometric and parts contact were considered for the door with body-in-white (BIW). Several door hinge designs, with integrated and independent check links, were investigated. Using the Von Mises stress and plastic strain from the above analysis, the fatigue life was predicted and compared with the test data. Integrating FEA and fatigue allows predicting the threshold total strain value, which is developed, for check load durability requirements. The strain-life plots were developed for both car and track programs to be used at the early design stage to estimate the fatigue life of the structure. Various material hardening models were evaluated. The strain hardened-isotropic hardening and cyclic-combined hardening were compared. This method improves design cycle time and reduces the warranty by producing a product design that comprehends the fatigue damage resultant from the application of check stop load to the door structure."
Direct Sensor Solutions for Anti Pinch and Collision Avoidance for Motorized Closures,"Motorized closures support the comfort in vehicles to an increasing degree. In the past the use of indirect sensors was an effective low-cost solution for anti pinch [1,2]. The demand for a reduction of the forces affecting the user and for minimized closing times leads to direct sensor solutions. A new aspect is the protection of moving vehicle parts, which we call collision avoidance. This paper deals with system aspects securing the movement area of motorized closures. An analysis is made for sliding doors, trunk lids and tailgates, pointing out the danger zones and the use cases. The result of a QFD (Qualitiy Function Deployment) with respect to the demands of the customer is shown. This leads to a rough description of the requirements for the technical solutions. A technology benchmark is conducted separately for anti-pinch and for collision avoidance. The two applications have distinct requirements; therefore different technological solutions are identified. As an example, the tailgate is examined in detail and a solution for securing the danger zones is presented. A Lab car is equipped and tested. For anti-pinch, a capacitive sensor system is selected and designed. Collision avoidance is realized by adopting a series automotive ultra-sonic sensor. Environmental influences are examined and described. Special integration problems and their solutions for both sensor systems are discussed. The topology of the electronic components is described and an outlook on the future is given."
Comparing the Harness Cost of Hardwired and Networked Integrated Door Systems,"The objective of the research discussed in this paper is to propose a methodology for comparing candidate electrical architectures on a cost basis at the very beginning of the architecture design process. To achieve this objective, historical data concerning the cost of a wiring harness for a driver’s door electrical system is analysed along with information on an electrical architecture for the door system of a small four door passenger car. The study is focused around a driver’s door electrical system based on LIN and hardwired integration. However, it is concluded that the results are applicable to other types of automotive electrical architectures."
Evaluation of Door Latch Response to Vertical Loading Conditions,"Field research has consistently demonstrated that the risk of occupant death or serious injury in motor vehicle crashes is significantly reduced when occupants are retained within the vehicle.[1][2] The injury prevention benefits of passenger vehicle door systems require that they remain closed during collisions. Federal Motor Vehicle Safety Standards (FMVSS) and SAE Recommended Practices set forth door latch performance requirements to “minimize the likelihood of occupants being thrown from the vehicle as a result of impact”. Currently, there is not a vertical latch strength requirement for hinged side doors in FMVSS 206. A recent study has raised concerns about latch performance in response to vertical loading conditions. In order to investigate door latch performance in response to vertical loading conditions, the latch must be evaluated using techniques more representative of loading conditions in real world accidents. This study investigates side door latch performance in full vehicle and door system component testing as opposed to the component-only fixture testing outlined in FMVSS 206. Both full vehicle and door system testing showed that the tested side door latches managed forces that were substantially higher than any loads required by FMVSS 206 when subjected to purely vertical loading."
A case-study about side door closing effort,"Door Closing Effort is one of the first impressions a potential customer has about a vehicle. The energy someone needs to give out to push and lock a side door vehicle is easily felt and can enhance the impression of a robust and high quality design vehicle. In other words, Door Closing Effort is one of the issues manufacturers shall look over in order to achieve perfect levels of Human Vehicle Integration (HVI). The aim of this paper is to present a case study of Side Door Closing Effort of a specific Hummer vehicle. It will be shown how door closing effort varies according to several parameters, and how to improve the design and/or production process in view of achieving better effort levels, considering the Hummer case as a background. Several variables that influence on the overall energy of this process have been evaluated, and the physical differences were weighted to demonstrate what really counts for reaching a comfortable level of Door Closing Effort."
Guidelines for vehicle development based on principles of universal design,"In order to fulfill the users' needs, many innovations are included in vehicles. However, not all of these vehicles can be used by People with Special Needs (PSN), due to their technical characteristics and/or adaptation cost, even with the financial incentives offered by Brazilian Government. In this context, the Universal Design (UD) is inserted, where PSN and people without physical deficiencies can use the same vehicle, with little or no adaptation. In order to identify the needs of PSN, interviews were carried out with PSN and exhibiters of automotive products for PSN, in the VII Reatech 2008 (International Fair of Technologies of Rehabilitation, Inclusion and Accessibility), where can be highlighted: to lower the car floor; to improve the door access (increasing width, height and opening angle); to improve the internal space of vehicles; to reduce the cost of adaptation kits; and others. Inclusion programs of the main Brazilian automotive manufacturers were also identified, focusing on kits for automotive adaptation, where some of them were preliminarily evaluated. Finally, general guidelines for vehicle development are proposed, based on principles of UD, results of interviews and a literature review."
Bake Hardening Steel (BH220) Characterization,"The bake hardening effect depends on three parameters i.e. pre-straining, paint baking temperature and paint baking time. The combined effect of all these parameters results into the increase in yield strength, called the “baking effect”. This paper explains the individual effects of these parameters on the baking value. Tensile test were carried out for the 495 samples baked at baking temperature from 140°C to 250°C with differential baking time of 10, 15, 20, 25 and 30 minutes and differential pre-straining of 2%, 3% and 5%. The differences of yield strength between the unbaked and baked sample were calculated and the increase in yield strength was noted. After these laboratory trials 800 numbers of door outer panels of a small truck were formed and finish painted. The increment in yield strength after component forming and painting was determined by taking tensile samples from three different locations of 5 painted doors. This would help shop floor optimization of the process parameters and the compatibility with various painting process vis a vis increase in bake hardening strength. It is also leading to a future work to understand clearly the correlation between the baking temperature, increase in strength and the micro structural changes."
Recycling Long Glass Fiber Reinforced Polypropylene Instrument Panel Trim Offal,"Production of soft, padded instrument panels (IP's) with a Long Fiber Reinforced Polypropylene (LFPP) substrate have areas for HVAC outlets, air bag doors, IP clusters and glove box doors that are molded over with substrate/ urethane foam/ skin. These openings are subsequently die punched out. These areas are molded over to prevent foam bleed to the backside of the IP during the production foaming process. Typically they are 12% of the total material usage. The punched sections of composite substrate/foam/skin (punch outs) have traditionally gone to landfill, typically at a cost of $0.05/lb. to the Tier 1 supplier. Wipag Recycling in Germany has developed a process whereby the substrate material is recovered from the composite structure, separating the resin from the foam and skin. The resin has 99.8% purity and can be subsequently blended back into virgin resin for production at a specified percentage without statistically varying the physical properties of the LFPP IP substrate. The WIPAG laminate separation process has been in commercial operation at American Commodities Inc. (ACI) in Flint, MI for the past 7 years albeit with SMA, PC/ABS and TPO substrates. With regard to recycling LFPP, traditional wisdom dictates that the material properties of the resin will be reduced after each heat history due to glass fiber length attrition, caused from the processing of the material. This study shows that up to 30% of resin reclaimed from the composite substrate can be added to virgin material with a minimal effect on the properties of the final part."
Applicability of Different Loudness Models to Time-Varying Sound in Vehicle,"Three sound loudness calculation models, including Zwicker instantaneous loudness model, Moore instantaneous loudness model and Moore time-varying loudness model, and the cited Zwicker time-varying loudness model in ArtemiS, were applied to calculate the time-varying loudness of three typical vehicle sounds, in particular. They are steady engine idle noise, impulsive door closing noise and order-swept electric vehicle pass-by noise. Based on the loudness amplitude and time-frequency loudness results, the applicability of the four loudness models to time-varying sounds was analyzed and compared. It was found that, both Zwicker and Moore time-varying loudness models are more reliable than Zwicker and Moore instantaneous loudness models if the sound amplitude and frequency vary tempestuously. And the time-frequency result of Moore instantaneous loudness model can be very helpful to noise source identification and mechanism analysis."
Invisible PAB Door Development Using Two-shot Molding,"Invisible Passenger-side Airbag (IPAB) door system must be designed with a weakened area such that the airbag will break through the Instrument Panel (IP) in the intended manner, with no flying debris at any temperature. At the same time, there must be no cracking or sharp edges at the head impact test (ECE 21.01). Needless to say, Head impact test must keep pace with the deployment test. In this paper, we suggested soft airbag door system that is integrally molded with a hard instrument panel by using Two-shot molding. First of all, we set up the design parameters of IPAB door for the optimal deployment and head impact performance by CAE analysis. And then we optimized the open-close time at each gate of the mold so that the soft and hard material could be integrally molded with the intended boundary. We could make the boundary of two materials more constant by controlling the open-close time of each gate with resin temperature sensor."
A Study on the Optimization of Body Structure for Rattle Noise by Exciting Woofer Speakers,"With the recent development of technologies for interpreting vibration and noise of vehicles, it has become possible for carmakers to reduce idle vibration and driving noise in the phase of preceding development. Thus, the issue of noise generation is drawing keen attention from production of prototype car through mass-production development. J. D. Power has surveyed the levels of customer satisfaction with all vehicles sold in the U.S. market and released the Initial Quality Study (IQS) index. As a growing number of emotional quality-related items are added to the IQS evaluation index, it is necessary to secure a sufficiently high quality level of low-frequency speaker sound against rattle noise. It is required to make a preceding review on the package tray panel, which is located at the bottom of the rear glass where the woofer speakers of a passenger sedan are installed, the door module panel in which the door speakers are built. Based on the theoretical background of robust design, this study seeks to suggest design criteria that are insensitive to the noise factors of the package tray panel."
Real-time Simulation of a Vehicle Door Locking Mechanism on a Hardware-in-the-Loop Platform,An automotive side door latch release mechanism has been modelled for the locking and unlocking vehicle functionality in Dymola. The performance of the developed door lock model is evaluated against an existing model of a similar door locking/unlocking system in Stateflow. The model performance is also compared with measurements from a real vehicle door latch. The model is converted into a Simulink model and built for a real-time environment such as the dSPACE target with a fixed step size solver. It is shown that a step size as small as 1 ms can be used for real-time simulation without task overrunning in the real-time target. The model is also benchmarked on a multiprocessor setup as multiprocessor simulators are common in system-level networked Electronic Controller Unit (ECU) testing facilities for implementing high fidelity closed loop models of integrated ECUs and actuators. It is proven that the developed door lock model in Dymola can be built and executed on a multiprocessor platform and there is much potential on the use of such models for future work in ECU testing.
Capitalizing on the Increased Flexibility that Comes from High Power Density Electrothermal Deicing,"This paper introduces a recent development in electrothermal heating technology that enables increased power densities on the leading edge of aircraft wings for the purpose of de-icing. Key aspects of this development include a high temperature heater mat, minimal thermal interference between the heating element and leading edge skin, a high quality bond of the heater to the skin and a power density profile that compensates for non-uniform thermal loads on the leading edge skin. Icing tunnel testing results corroborate the value of these key aspects in enabling operation at extreme power densities, even to the point of achieving full evaporative anti-icing operation under Intermittent Maximum conditions. The advent of higher power density capabilities has opened the door to new approaches to electrothermal deicing that were previously impracticable. Some of these new approaches and their benefits are presented."
Vehicle Roof Strength Test Procedure,This SAE Recommended Practice establishes a uniform laboratory test method to evaluate the strength characteristics of roof systems. The test procedure is intended to provide reliable and repeatable results and to permit numerical comparisons. A test is conducted in which the vehicle roof system is loaded under controlled laboratory conditions. Structural strength measurements are obtained under load application angles chosen to concentrate forces on the forward portions of the roof panel and roof supporting structure.
Passenger Car Door System Crush Test Procedure,This SAE Recommended Practice establishes a uniform laboratory test method to evaluate the capability of passenger car door systems to resist a concentrated lateral inward load. The procedure is intended to provide repeatable results and to permit numerical comparisons. A test is conducted in which the door and related structural members of the vehicle are loaded under controlled laboratory conditions. Structural strength measurements obtained under these conditions are reproducible. Background information and rationale for the test procedures described in this Recommended Practice are provided in the Appendix.
"Door-Closing Sound Quality Improvement Process Based on Beamforming Method, Wavelet Analysis, and Component Design Optimization","Door-closing sound quality is a very important noise, vibration, and harshness (NVH) attribute since it may have a significant impact on customers’ perception, recognition, and luxury sensation of an automobile brand. Therefore, its evaluation methodology and design process have been one of the research and engineering efforts for all NVH organizations in the automotive industry. In many cases, the resolution of a door-closing sound quality issue lacks a systematic approach, and engineers rush to work when an issue surfaces. While subjective evaluation may easily find a door-closing sound problem, it oftentimes cannot directly pinpoint and go right to the root cause of the issues, and engineers could only guesstimate the possible relevant structural components based on past experiences. In this work, a door-closing sound quality development process, which has already been implemented in vehicle programs, is summarized and presented. The process involves a systematic workflow in a relatively short turnaround time. It begins with the beamforming method to carry out the sound source localization to facilitate the accurate determination of the key areas that impact the door-closing sound quality and then followed by objective measurements to acquire the sound data for the examination of the temporal behavior and spectral content processed by the wavelet analysis. After a better understanding of the key components along with the sound characteristics obtained, the effort is then focused on the investigation of the component mechanisms and optimization of the relevant hardware kinematics. A case study based on a high-end passenger vehicle is presented, and in this particular example, it is found that the door latch design and weather strip on the upper window frame are the critical components. Once the design proposal is implemented, the door-closing sound quality has finally met the program target."
An Overview of Automotive Wind Noise and Buffeting Active Control,"As the wind speed increases, the contribution of wind noise gradually exceeds other noise sources, affecting comfort. First, the classification of automotive wind noise is discussed in detail according to the formation mechanism, sound analogy, and pressure type. Then the wind noise evaluation and development tools are summarized. Finally, the characteristics and control means of vehicle window-induced buffeting noise are discussed. Considering the appearance and field of view, it is currently difficult to control side window buffeting based on passive methods. Therefore, the proposed method of actively controlling the window opening size, actively opening multiple windows, and even releasing an inverse phase sound source based on control logic has a good application prospect."
Wind Noise Contribution Analysis,"This article is motivated by observations of the wind tunnel measurement data acquired during benchmarking and program development for a variety of passenger vehicles over the years. In wind noise development, contribution analysis is a common practice to screen and identify the most significant sources and paths. In order to shed light on the whole picture of the contribution analysis, the work presented in this article falls into two categories. One is the analysis of underlying mechanisms for a better understanding of the phenomena observed in the contribution results. The other is the summarization of wind noise contributions obtained by wind tunnel testing for some representative subsystems, e.g., the contributions based on different reference states, the effect of grilles, underbody, acoustic glass, and auditory masking. A close look at the obtained numbers for each vehicle reveals that all these numbers have their intrinsic characteristics, and the same number may not tell the same story. The components with the same design, cost, and quality behave differently in vehicles with different wind noise levels. This work shows that contributions are generally reference-based and vehicle-dependent, and vary when the reference state is deviated even for the same vehicle. The same subsystem contributes more to a quiet vehicle than a mediocre vehicle, thereby a direct comparison of contributions among different vehicles is unfair and biased against quieter vehicles. As a first approximation, a quantitative estimation is derived to promote a qualitative understanding. It is used to facilitate a fair comparison of contributions, which are based on different reference states from either the same vehicle or different vehicles. It also implies that a vehicle with superior wind noise performance carries with it a much more stringent standard in subsystem design than an average vehicle even though their contribution targets are similar. The understanding of the work presented in this article would further benefit the interpretation of various contribution results, their comparison, and subsystem target setting."
Finite Element Model Reduction Applied to Nonlinear Impact Simulation for Squeak and Rattle Prediction,"Increasing demand for simulation accuracy often leads to increased finite element model complexity, which in turn, results in higher computational costs. As a provision, component mode synthesis approaches are employed to approximate the system response by using dynamic substructuring and model reduction techniques in linear systems. However, the use of available model reduction techniques in nonlinear problems containing the contact type of nonlinearities remains an interesting topic. In this paper, the application of a component mode synthesis method in squeak and rattle nonlinear simulation has been investigated. Critical regions for squeak and rattle of the side door model of a passenger car were modelled by nonlinear contact definition in finite element simulation. Craig-Bampton model reduction method was employed to substructure the finite element model while keeping the nonlinear contacts in the model. The model response was evaluated using the modal assurance criterion, frequency response analysis and contact force magnitude in comparison with the baseline model. Results showed that a great reduction in computational time (about 98%) can be achieved while the accuracy of the system response was maintained at an acceptable range for the intended application for squeak and rattle simulation. Although the prediction of impact events in time was done accurately, the contact force magnitude was estimated with average error of 2.5% to 22%, compared with the baseline results. The outcomes of the study show that to empower squeak and rattle prediction by including contact interfaces in finite element simulations, implementation of the model reduction approach can compensate the simulation cost."
Passenger Car Door Closing Effort Prediction Using Virtual Simulation and Validation,"In the automobile industry, the door closing effort spells out the engineering and quality of the vehicle. After the visual impact a vehicle has on the customer, the doors are most likely the very first part of the vehicle he/she encounters, to enter and exit the vehicle. One of the customer’s very first impressions about the quality of the car is given by the behavior of the doors when opening and closing, the swinging velocity and the energy that is required to obtain a full latching that the door makes when closed by the user. Door closing effort gives an indication of how good or bad the vehicle is engineered. The purpose of this paper is to propose modifications in the door system which help in reduction of door closing effort or velocity by two different methods, EZ Slam Door and Bungee Rope. In this paper, parameters like hinge friction, hinge axis inclination, sealing, latch and air bind effect are analyzed which affect door closing effort. A virtual model is prepared in MSC.ADAMS to evaluate door closing velocity through calculating energy contribution by each parameter. Door closing effort or velocity is calculated for the existing model and to improve the existing scenario, design modifications are proposed. These design modifications after implementation have shown 20% reduction in door closing effort or velocity. Physical validation was done, and results were found in line with the virtual simulation. The correct method for door closing effort prediction is proposed based on real world customer usage pattern."
Deep Generative Design Models for Improved Door Frame Performance,"Significance of CAE simulation thus is increasing because of its ability to predict the failure faster, also lot of design combinations can be evaluated with this before physical testing. Frame stiffness of side doors is one of the major criteria of a vehicle closure system. In most cases, designers around the globe will be designing same or very similar side door frame structures recurrently. In addition, in the current growing trend having an optimized side door frame design in quick time is very challenging. In this investigation, a new artificial intelligence (AI) approach was demonstrated to design and optimize frame reinforcement based on machine learning, which has been successful in many fields owing to its ability to process big data, can be used in structural design and optimization. This deep learning-based model is able to achieve accurate predictions of nonlinear structure-parameters relationships using deep neural networks. The optimized designs with optimization objectives as deflection is obtained efficiently and precisely using Bayesian Optimization algorithm. Deep learned computational results were validated by the experimental results. Furthermore, the developed deep neural networks show how various design sections of door frame structures behave and how it can be used as a reference for future door design through deep generative model techniques. Keywords: Door Frame Reinforcement, Deflection, Deep neural networks, Bayesian Optimization algorithm"
1D Modeling of HVAC Unit Air Flow for Automatic Climate Control Simulations,"Advanced control techniques are widely used in different automotive applications including climate control. Significant costs associated with the development and calibration of such controllers can be reduced if these tasks are conducted in a virtual environment. Such a virtual environment can be developed by integrating the controller with the system model. Different scenarios can be then simulated to make sure functional objectives of the system are met. 1D models provide the necessary level of accuracy without imposing extra computational cost in such virtual environments. As such, they are perfect candidates for model, hardware or software-in-the loop validation benches for controls. Performance of a heating, ventilation and air-conditioning (HVAC) system can be controlled through the settings of the components like mode door, blend door, recirculation door, blower, and the compressor. In an automatic climate control (ACC) system, these factors are automatically actuated to achieve thermal comfort. For development and calibration of ACC systems, virtual setups with a model of HVAC unit can be used. In this case, the model should capture the flow inside the HVAC unit which could be impacted by the door positions. This paper proposes a 1D model for HVAC unit air flow, where components such as mode door, blend door, recirculation door, and blower are modeled and calibrated. Capability of the model to predict temperature values along the unit is then validated against test data. The promising results demonstrate the model potential in ACC virtual development and calibration. This can reduce the number of tests needed and help minimize the cost, effort, and possible delays in product development."
Analysis of Discretization for Transient Impact Loads on Door Closing,"The transient impact load generated by door closing is used as the input of the closing condition, which is an important part of door system investigation. In this article, the basic theory of transfer path analysis (TPA) is introduced to handle the abnormal vibration of the front-left door with the glass down stall position of a certain vehicle during the closure. The transient impact loads are discretized under the closed door and obtained using the inverse matrix (IM) method in TPA. Vehicle test and bench test are conducted. The closed door is subjected to the transient impact loads of the sealing strip and the latch on the body side. In the vehicle test, acceleration sensors are pasted on the target point and the reference point on the door to obtain the acceleration vibration response upon the door closure. In the bench test, when the hammer strikes the excitation points, the frequency response functions (FRFs) from these points to the reference point and to the target point are recorded by the acceleration sensors. The vibration amplitude of the front-left door with the glass down stall position is taken as the criterion. Finally, a reasonable discretization number of the door-closing transient impact loads is determined, which provides guidance for subsequent research of the door system."
Air Bind Effect on Door Slam Durability Performance,"In the vehicle development process, the door slam durability assessment is of significant importance in the estimation of fatigue life for body closure system. So far, various exertions have been taken into consideration to better represent the door slam simulation for door durability performance. Nowadays, with computer aided engineering (CAE) being extensively implemented, simulation procedures are constantly being investigated in order to get precise outcomes as physical testing. In a real world scenario, the customer closes the door frequently against the sealed cabin which offers the cabin pressure to close. The cabin pressure acts in the opposite direction of door closing providing the damping effect and minimizes the overall damage to the structure. Currently, simulations are focused on determining the total energy required for closing the door by summing up the energy lost in the weather seal and latch. Often the energy required to overcome the air-bind effect is neglected in the analysis. This work addresses the air bind effect on structural durability performance of swing door, simulating customer usage over a 10-year vehicle lifecycle with using stress analysis in explicit solver and strain-life analysis in fatigue solver."
Prediction of Automotive Side Swing Door Closing Effort,"The door closing effort is a quality issue concerning both automobile designers and customers. This paper describes an Excel based mathematical model for predicting the side door closing effort in terms of the required minimum energy or velocity, to close the door from a small open position when the check-link ceases to function. A simplified but comprehensive model is developed which includes the cabin pressure (air bind), seal compression, door weight, latch effort, and hinge friction effects. The flexibility of the door and car body is ignored. Because the model simplification introduces errors, we calibrate it using measured data. Calibration is also necessary because some input parameters are difficult to obtain directly. In this work, we provide the option to calibrate the hinge model, the latch model, the seal compression model, and the air bind model. The door weight effect is geometrically exact, and does not need calibration. The capabilities and accuracy of the developed model are demonstrated using the front and rear doors of a production vehicle."
Mixture Distributions in Autonomous Decision-Making for Industry 4.0,"Industry 4.0 is expected to revolutionize product development and, in particular, manufacturing systems. Cyber-physical production systems and digital twins of the product and process already provide the means to predict possible future states of the final product, given the current production parameters. With the advent of further data integration coupled with the need for autonomous decision-making, methods are needed to make decisions in real time and in an environment of uncertainty in both the possible outcomes and in the stakeholders’ preferences over them. This article proposes a method of autonomous decision-making in data-intensive environments, such as a cyber-physical assembly system. Theoretical results in group decision-making and utility maximization using mixture distributions are presented. This allows us to perform calculations on expected utility accurately and efficiently through closed-form expressions, which are also provided. The practical value of the method is illustrated with a door assembly example and compared to traditional random assembly methods and results."
A Study on Various Structural Concepts of Automotive Door Trim,"An automobile door is a complex module, which consists of various fixed and movable subassemblies and components. Parameters such as safety, vehicle dynamics, aesthetic and strength are critical while designing the door assembly. Apart from the above, the design of door trim should minimize BSR (buzz squeak and rattle) at vehicle running conditions. Stiffness is one of the key engineering requirements which if not optimized will result in higher BSR levels and failure of the door trim components. In this study, more importance is given to optimize the stiffness of door trim. As per DVP (design verification and planning) standards of the OEMs, the range of deflection for the plastic trim parts is defined considering the conditions, comfort level and location of use. If stiffness is higher than the requirement, the door trim plastic parts are harder and will violate the quality and safety norms. If it is lower, then trim parts will not meet the functional requirements and safety norms. To achieve the optimized stiffness within the range, various design proposals capturing different structural concepts are constructed and analyzed."
Internal Pressure Characteristics when Evaluating Dynamic Door Blow Out Deflection,"Wind noise is one of the most influential NVH attributes that impact customer sensation of vehicle interior quietness. Among many factors that influence wind noise performance, the amount of dynamic door deflection under the pressure load due to fast movement of a vehicle plays a key roll. Excessive deflection could potentially lead to loss of sealing contact, causing aspiration leakage, which creates an effectual path through which the exterior aerodynamically induced noise propagates into the vehicle cabin. The dynamic door deflection can be predicted using CFD and CAE approaches which, in addition to modeling the structure correctly, require a correct pressure loading composed of external and internal pressure distributions. The determination of external pressure distributions can be fulfilled fairly straightforward by using commercial CFD codes such as Fluent, Star CCM+, Powerflow and others. However, the capability of predicting the internal pressure due to high wind speed outside of a vehicle has not been developed. This work looks into the internal pressure characteristics associated with the dynamic loading setup that is required for analytical efforts. The work is based on the wind tunnel measurement data involving several vehicles. By comparing the measured internal pressure data, along with CAE results, the issues are summarized and a conservative internal pressure load value is recommended."
Structural Integrity Evaluation of Plastic Welding (Heat Stake) Tower in Door Trim Panels of Vehicles Using Finite Element Method,"Structural integrity is a characteristic that must be evaluated during development of plastic parts as door trim panels. One of the critical areas in door trims is the interface between different parts that often use heat stakes due to process capacity and low costs. To predict issue on those interfaces, a methodology combining finite element analysis (FEA) and physical test results was applied to drive design in two door trim designs, with different material combinations. Aiming to support FEA conclusions, physical tests were performed to determine the maximum retention force that a heat stake withstands, indicating values about 168N for heat stakes of medium impact polypropylene blend >PP+EP(D)M-T<. and 216N for stakes of unfilled polypropylene copolymer >PP<. These values were used as upper limits for reaction forces provided by FEA in each heat stake under a load of 600 N at Pull Handle. The results for first door trim design indicated no structural issue in any heat stake, what generated a weld process investigation. Its conclusion indicated as root cause the weld quality. The results for second door trim design indicated an issue in one heat stake that required a relocation to redistribute the load. After including a new heat stake and redistributing their position, simulation indicated lower efforts, meeting the requirements. This methodology proved to be efficient to evaluate heat stakes performance during door trim development process."
Small Overlap Impact Countermeasure-Front Door Hinge Pillar Dual Box,"Since the inception of the IIHS Small Overlap Impact (SOI) test in 2012, automotive manufacturers have implemented many solutions in the vehicle body structure to achieve an IIHS “Good” rating. There are two main areas of the vehicle: forward of vehicle cockpit and immediately surrounding the vehicle cockpit, which typically work together for SOI to mitigate crash energy and prevent intrusion into the passenger zones. The structures forward of vehicle cockpit are designed to either 1) absorb vehicle energy from impact to the barrier, or 2) provide enough strength and rigidity to aid deflection of the vehicle away from the barrier. The structures which are immediately surrounding the vehicle cockpit (known as pillars and rocker/sills) are traditionally components designed to be highly rigid sheet metal panels to protect the occupant during crash events. This paper focuses on a concept for a portion of the cockpit structure that combines energy absorption and high rigidity structure, which are not typical in this area of a vehicle’s architecture. Using CAE methods, it is observed that a vehicle’s SOI structural rating will be enhanced utilizing the presented concept."
Evaluation of Minimum Door Closing Velocity Using Analytical Approach,"Door closing velocity (DCV) is one of the important design parameter for door durability performance. The closing velocity varies with the design parameters and physical properties of the door. The variation in door closing effort may increase or decrease the durability of the door and body components, this can be a concern when the overall vehicle durability performance is considered. This paper gives a mathematical model to calculate the door closing effort accounting the energy sink from various door design parameters such as door seal, latch, hinge, door weight, checkstrap and cabin-pressure. In addition to this, the MS-Excel based computation tool has been developed, which aims to calculate the door closing velocity and energy contribution from each design parameter. This tool is very interactive and effective for durability engineer and helps in improving the quality of vehicle door design. This paper also provides the result comparison study with CAE approach for design parameters as seal stiffness, latch, hinge, door weight and checkstrap."
Innovative Door Design for Commercial Vehicles,"Design of body structures for commercial vehicles differs significantly from automotive due to government, design and usage requirements. Specifically, heavy truck doors are not required to meet side impact requirements due to their height off the ground as compared to automobiles. However, heavy truck doors are subjected to higher loads, longer life, and cannot experience permanent deformation from overload events. Aluminum has been used intensively in commercial vehicle doors and cab structures for over 50 years by several different manufacturers in North America. It has been only in the last few years that aluminum has appeared in automotive door structures other than in high-end luxury vehicles. Commercial vehicle customers are expecting the same features found in premium automobiles resulting in opportunities to learn from each other's designs. In order to optimize the strength and weight of a commercial vehicle door, a new aluminum intensive structure was developed. The new structure featured a unique architecture that was the first in the industry to use a multi-cavity aluminum extrusion joined to stamped sheet reinforcements in order to provide a direct load path between the hinges and the latch. The shape of the extrusion also allows the use of a one piece glass and door mounted mirror. The “barn door” architecture of the inner structure of the door allowed for gauge optimization of the both the inner and outer stampings, the two largest and heaviest components of the assembly. Additionally, the use of an extrusion allowed for a single drop glass for improved visibility and the ability to use a door mounted mirror with only one extra reinforcement. Overall the design architecture used in the new doors provide best in class structural performance, sealing and features normally found in luxury automobiles for the first time in the heavy truck industry."
Striker with bumper implementation to improve chucking noise issues,"Investing in quality as added value to products becomes a means of guaranteeing satisfaction as well as customer loyalty, making it competitive in its respective segment. In the automotive business, this has not been different, It can observed a progress in the perception and customers demand in quality in the last few years. At the same time, that the industries need to guarantee the cost and time of response to the dissatisfaction of the customers. In this project, was possible to implement a locking door concept, with an effective solution to the door vibration problem in a B platform, vehicle model in South America."
The Study of Optimization of Sliding Door Effect,"A sliding door system is one of the vehicle door types, which is generally applied to the MPVs. The Sliding door is contains three rails (an upper, a center, and lower rail), which are mounted on body structure, and three rollers (the upper roller, the center roller, Lower roller), which are mounted on the sliding door side. The system is different from a swing door, rotated by hinge axis. To set up sliding door layout for better performance, predict operating force is one of the main factors, But The door moving trace is on three-dimension, hard to calculate and predict. So in this study, it is an object to analyze the impact between the main factors affecting the performance of the closing and open performance and the sliding door through the study formula and a layout scheme for ensuring the best operating performance of the sliding doors."
Automatic Drilling and Fastening System for Large Aircraft Doors,"Electroimpact has developed a system for drilling and fastening of cargo door structures which efficiently addresses many of the manufacturing challenges that such parts present. Challenges to door automation include 1) the presence of an inner skin that must be processed, in addition to the outer skin, and 2) a stiff frame structure, which makes the clamping and drilling processes that are typical to automated fastening machines very unforgiving of any errors in workpiece positioning. In this case, the manufacturing cell was to be installed in an existing facility with very limited ceiling height, further complicating the system and process design. New methods were devised to solve these problems, and the solutions found will likely have utility in future applications."
In-Situ Characterization of Vibrations from a Door Mounted Loudspeaker,"In the automotive industry, there is an increasing need for gaining efficiency and confidence in the prediction capability for various attributes. Often, one component or sub-system is used in a number of car models of one vehicle platform. Many of these components are potential sources of noise, vibration and squeak and rattle. In order to provide an early prognosis, vibro-acoustic source characterization in combination with the source-to-response transfer behavior are required. This paper describes the process of predicting the vibrational behavior due to a woofer, which could induce squeak and rattle, on a door panel. Blocked forces, determined indirectly in-situ by frequency response functions and operational accelerations, were used for quantifying the source activity. Those forces were in a second step loaded on to a finite element model in order to predict the response when the speaker was mounted to another position in an upcoming car model. Prior to this, comparisons between the measured and simulated response for the same car model were made, with satisfying agreement."
Trimmed Door Audio Response Hybrid Modeling Assessment,"The door response to audio excitation contributes to the overall performance of a vehicle audio system on several items: acting as a cabinet, it influences the loudspeaker response, but it also radiates unwanted sound through the inner door panel. Associated design issues are numerous, from the loudspeaker design to door structure and inner panel definition. Modeling then appears as an unavoidable tool to handle the acoustic response of the loudspeaker in its actual surrounding as well as the door inner panel radiation. In the low frequency range (<300 Hz), the loudspeaker is conveniently modelled using the classical Thiele&Small 1 D model. The interaction with the door and the acoustic surroundings requires a more detailed Finite Element modeling considering the acoustic loads on both sides of the loudspeaker membrane and the force at the loudspeaker frame interface with the door structure. The proposed hybrid modeling is first assessed by comparison of the computed and the measured membrane’s displacement. An update of the T&S parameters is performed in order to optimize the model. Then, the computed loudspeaker frame displacement and the acoustic loads may be checked against measurement. Finally, the computed vibrational response of the trimmed door is compared to an extensive 3D LASER measurement. Such an analysis allows the loudspeaker membrane displacement control as well as the inner door panel’s motion that may radiate unwanted sound. Previously proposed indicators are used to quantify the door audio performance."
Vehicle Side Safety Enhancement through Door Intrusion Barrier Analysis and Recuperation,"The automobile industry is making huge strides to improve vehicle and occupant safety. A lot of safety improvements and modifications have been made in the past decade. But the side impact is still overlooked as not much has been improved for side safety despite most of the accidents and collisions happen to the side of a vehicle. Door intrusion barriers are the primary protection feature along with A, B and C pillars. Crashworthiness mainly depends on the position, cross-section and material of the intrusion barrier. So, our work mainly focuses on finding the optimum position, choosing the correct cross-section and finding the right material for the intrusion barrier. The objective of this project is to minimize the damage to the side of the vehicle by increasing its crashworthiness thereby reducing passenger injuries. A model of a vehicle door has been designed in Solid Works and various cross sections of door intrusion barriers like circular, rectangular, H-section, I section, E and C section have been developed. The crash test has been conducted according to New Car Assessment Program (NCAP) norms and the best possible configuration with highest safety level has been found. The barrier developed successfully reduced deformation by 36.667% and was subjected to a much lesser stress which was 28% lower than the existing barriers."
"Virtual Simulation of Door Slam Test, Study of Relative Sensitive Parameters and Correlation with Physical Test","Door slam test is one of the important durability tests in door design and development. Door requires to meet certain performance requirements like it should close properly (no metal to metal contact), there should not be any leakage, and closing operation should be smooth & with minimal effort and it should survive the life of the vehicle. Virtual simulation of door slam test, correlation with physical test results and effect of various parameters like seals stiffness are demonstrated in this study. Slam Analysis was carried out in LS-Dyna solver before physical test. This not only helped in avoiding initial structural design flaws, but also helped us in deciding door latch position, effect of mass distribution in the door and study of force distribution between primary seal, secondary seal and door latch. Primary and secondary seals played a critical role in the analysis. An intended length of both the seals was tested first to get its stiffness curve. Then it was modeled in the way that stiffness of one beam represented the stiffness of testing length. An in-house developed physical test was carried out for the intended cycles. A good correlation between simulation and test results is achieved. Overall detailed study of door slam test, simulation methodology and effect of various relative parameters on performance has become very important step in design and development of door assembly."
Automotive Door Opening Durability Simulation Using Detail Checkstrap Mechanism,"In automotive design space, door opening durability is one of the important design attribute to build a door structure. Customer often interact with door while ingress and egress a vehicle and that builds a perception of vehicle in customer’s mind. Now days, Computer Aided Engineering (CAE) is used extensively to simulate the real time door opening and closing event for designing the door structure for durability performance. Early prediction of durability performance and developing the countermeasures saves great amount of time and cost. This paper provides a brief study of detail checkstrap mechanism and its influence on door durability performance. Door checkstrap plays an important role in swing door design, it assists the door opening and closing with the help of check arm profile guided by roller and spring. This allows the load transferred from door to body through checkstrap first and then through hinges. The load interval between door full open to door over-open becomes critical for door durability performance. During this event, the majority of energy absorbed by the checkstrap mechanism and attached door & body components. Hence, the checkstrap mechanism representation is very important for the door durability simulation. Door dynamic analysis for overopen load is performed in LSDYNA solver and fatigue analysis is performed in nCode."
A Robust Structure Analysis on Automotive Door Armrest,"An automobile door is one vital commodity which has its role in vehicle’s function, strength, safety, dynamics and aesthetic parameters. The door system comprises of individual components and sub-assemblies such as door upper, bolster, armrest, door main panel, map-pocket, handle, speaker and tweeter grille. Among them, armrest is an integral part which provides function and also takes care of some safety parameter for the customers. The basic function of an armrest is to provide ergonomic relief to occupant for resting his hand. Along with this, it also facilitates occupant safety during a side impact collision by absorbing the energy and not imparting the reactive force on occupant. Thus an armrest has evolved as a feature of passive safety. The armrest design should be stiff enough to withstand required elbow load condition with-in the acceptable deflection criteria. On the other hand, armrest has to absorb the dynamic force by deflecting proportionally to the side impact load. In this study the various structure of armrest was analyzed to strike an ideal zone between functional and safety parameters. The scope is to improve the functional requirement, i.e., the side impact metrics and also to reduce the variation among the noise factors such as manufacturing tolerance, location of side impact and BIW rigidity. For this, DFSS way of approach is handled to optimize a robust design which provides enhanced passive safety for customer. This optimized passive safety armrest design can be used for upcoming programs and the development lead time can be reduced considerably."
A Study of Design Methodology to Develop Improved Door System of a Vehicle,"In the past few years, technological innovations in the automobile industry took vehicle performance to the next level. One such innovation is frame integrated panel door. This type of door helps automobile companies to have the advantages of both conventional panel and frame type doors. Though it has a good number of advantages, there are some drawbacks too. It requires improvements in its quality, NVH performance, weight and etc. Quality of a door is low due to the limitations in structural design and manufacturing technologies. And it is difficult to have a robust structure which leads to degradation of key performing factors such as NVH. For a lightweight vehicle, it is important to design an optimized structure for saving weight, without compromising its performance. In order to overcome these drawbacks a new optimized design structure is required for door system. This Research paper is about a systematic design methodology for Development of a new optimized door structural design by a comprehensive engineering design analysis of existing design constrains and drawbacks. The design methodology is described as below. Step 1 is the System analysis. The correlation of all components constituting the door was schematized and their functional relationships were modeled to analyze door system. Step 2 is the Problem analysis. The occurrence-sequence mechanism for problems was enumerated and the root cause was analyzed by investigating up to the sub ordinate level components in door system. Step 3 is deriving the concepts. Using the theory of inventive problem solving techniques, new concepts were derived from a variety of parameters such as new structures, materials and manufacturing processes. Step 4 is the Specification optimization. New design is evaluated for possible optimization in its specifications. Based on evaluation result optimal specifications are selected. Step 5 is the performance evaluation. The performance is verified by evaluating the new structure of the system. Following the above design process, a new door system with an initial design objective was developed."
A Development of the New Mechanism for Preventing Door Opening in Side Impact Test,"During a new vehicle development process, there are several requirements for side impact test that should be confirmed. One of the requirements is the prevention of door opening during side impact test. Even though there are many causes for door opening problem, this study deals with inertia effect by impact energy. Until now, there have been two classical methods to prevent car door from opening in side impact. One is the increment of the inertia resistance by increasing the mass of the balance weight and the spring force. The other is the application of the blocking lever. Unfortunately, in spite of our efforts, the door opening problem occurs occasionally. Therefore, to improve the problem fundamentally, this paper proposes a new blocking lever mechanism that work similar to ball-point pen structure. The proposed mechanism fixes the blocking lever when the opening directional inertia force is applied to the door outside handle during side crash. With this, it is possible to prevent vehicle door from opening during side impact. Additionally, it is possible to reduce the weight of door outside handle and the spring force."
Multidisciplinary Design Optimization of Automobile Tail Door,"Stringent emission norms by government and higher fuel economy targets have urged automotive companies to look beyond conventional methods of optimization to achieve an optimal design with minimum mass, which also meets the desired level of performance targets at the system as well as at vehicle level. In conventional optimization method, experts from each domain work independently to improve the performance based on their domain knowledge which may not lead to optimum design considering the performance parameters of all domain. It is time consuming and tedious process as it is an iterative method. Also, it fails to highlight the conflicting design solutions. With an increase in computational power, automotive companies are now adopting Multi-Disciplinary Optimization (MDO) approach which is capable of handling heterogeneous domains in parallel. It facilitates to understand the limitations of performances of all domains to achieve good balance between them. The paper presents the MDO of a Tail door of a sports utility vehicle (SUV) which is carried out at the stage where major structural design has been finalized, and the only gauge of the tail door panels can be taken for design variables. The objective of the exercise was to minimize the mass while meeting various performance parameters. Modal and frequency response function (FRF) load cases are considered for noise vibration and harshness (NVH) domain and stiffness load cases for durability domain. Crashworthiness domain load cases for the tail door were not considered here because crash norms are not applicable for rear impact. Response surface based optimization method has been selected for the optimization considering resource availability and dexterity of being applied in various domains. A sensitivity study was used to identify critical panels for each performance parameter. Broken constraint charts were studied to identify the load cases which limit the mass reduction opportunity. The study showed twelve percent of mass saving which is significant for automotive doors."
Effect of PVC Skin and Its Properties on Automotive Door Trim Inserts,"Plastic plays a major role in automotive interiors. Till now most of the Indian automobile industries are using plastics mainly to cover the bare sheet metal panels and to reduce the weight of the vehicle along with safety concerns. Eventually Indian customer requirement is changing towards luxury vehicles. Premium look and luxury feel of the vehicle plays an equal role along with fuel economy and cost. Interior cabin is the place where aesthetics and comfort is the key to attract customers. Door Trims are one of the major areas of interiors where one can be able to provide premium feeling to the customer by giving PVC skin and decorative inserts. This paper deals with different types of PVC skins and its properties based on process constraints, complexity of the inserts. Door trim inserts can be manufactured by various methods like adhesive pasting, thermo-compression molding and low pressure injection molding process etc. Considering process feasibility and PVC skin manufacturing constraints, it will be a challenge to decide the specifications of the PVC skin to achieve good quality product. The objective of this paper is to review the effect of PVC skin & its properties on door trim inserts using Low pressure injection molding and discuss steps involved in selecting the appropriate PVC skin."
A Study on Optimization of the Ride Comfort of the Sliding Door Based on Rigid-Flexible Coupling Multi-Body Model,"To solve the problem of serious roller wear and improve the smoothness of the sliding door motion process, the rigid-flexible coupling multi-body model of the vehicle sliding door was built in ADAMS. Force boundary conditions of the model were determined to meet the speed requirement of monitoring point and time requirement of door opening-closing process according to the bench test specification. The results of dynamic simulation agreed well with that of test so the practicability and credibility of the model was verified. In the optimization of the ride comfort of the sliding door, two different schemes were proposed. The one was to optimize the position of hinge pivots and the other was to optimize the structural parameters of the middle guide. The impact load of lead roller on middle guide, the curvature of the motion trajectory and angular acceleration of the sliding door centroid were taken as optimization objectives. In the first scheme, multiple sets of sample models were obtained by using orthogonal experimental design and approximate surrogate models were established with the method of RSM, Kriging and RBF. However, the optimum solution couldn’t be obtained because the optimization objectives are highly nonlinear with respect to the design variables. To solve the problem, an improved optimization method of hierarchical encryption was adopted and obtained the optimum solution finally. In the second scheme, the structural parameters with the best ride performance was obtained by using the evaluation function method. The proposed study improves not only the ride comfort of the sliding door, but also has great significance for the preliminary design and development of the sliding door."
Minimizing the Rattling of Door Glass,"Significant effort has been expended to improve the sound made by a closing car door. This study focuses on reducing door glass rattle sounds, not only evaluating the rattle influence of door glass support but also introducing an approach to reduce glass rattle noise by using sealing components. The first part of the study is dedicated to minimizing vibration. A jig is constructed to evaluate the influence of a door glass support on the rattling. The jig is employed so that the glass meshing between the A and B pillars can be controlled; the glass holder moves in the x- and z-directions and the belt molding moves in the y-direction. An impact hammer test was adopted for investigating door glass rattle. The frequency response obtained via impact hammer testing is analyzed by varying the glass support points and important factors that should be considered in early design stages are obtained. The second study is about optimizing vibration absorption. A glass run, door-side weather-strip, and body-side weather-strip are used to absorb vibration. The glass run section is created through the TRIZ technique. Performance evaluation of the rattle in this section show that the damping speed improved by 35% compared with the damping speed of the existing glass run, rendering it possible to significantly reduce glass rattle noise. This study suggests an approach to reducing both the vibration caused by DR BIW and door glass rattle noise using weather-strips. This research also shows that the door-side weather-strip is the most useful in reducing rattle noise. This study provides greater insight and access to the door glass rattle problem."
Door Audio Response Hybrid Modeling and Assesment,"The door response to audio excitation contributes to the overall performance of the audio system on several items. First, acting as a cabinet, it influences the loudspeaker response. Second, due to the door trim inner panel radiation, the radiated power is disturbed. A third effect is the regular occurrence of squeak and rattle, that will not be considered at this stage. Design issues regarding these attributes are numerous, from the loudspeaker design to door structure and trim definition. Modeling then appears as an unavoidable tool to handle the acoustic response of the loudspeaker in its actual surrounding. Since most of the issues are related to low frequency excitations (<200 Hz), and considering the fact that several loudspeaker references may be used in the same door, it was chosen to model the system in a hybrid manner: the electro-dynamical behavior of the speaker is modelled using a classical 1D modelling (Thiele and Small) while the door vibro-acoustic behavior is modelled by means of Finite Elements. After the vibroacoustic coupling between the loudspeaker and the door is fully described, transmission paths are investigated, showing possible simplifications. Electroacoustical indicators are then proposed to control the door design regarding audio quality issues. Sensitivity of the indicators to some design variables will then be shown."
Simplified CAE Model Technique to Predict Crush Performance of Identical Sized Passenger Vehicle Doors,"This paper highlights a simplified CAE model technique, which can simulate and predict door crush strength performance quickly. Such quick models can be used for DFSS and Design change studies. The proposed method suggests an equivalent sub model technique using only the door beam with tuned stiffness end springs to predict FMVSS214S full vehicle crush performance. Such models can be solved in minutes and hence very useful for DFSS studies during product design. The proposed method can be used to finalize door beam design for identical size of vehicle doors to meet required FMVSS214S crush performance. The paper highlights the door beam end springs tuning for identical size of cars and SUVs. Four vehicles were considered for the study. A single spring F-D (force -displacement) is tuned which correlated well for frond door of all the four vehicles. A separate unique spring F-D was needed which correlated well for rear door of all the 4 vehicles."
A Research on the Prediction of Door Opening by the Inertia Effect during a Side Impact Crash,"The purpose of this study is to develop a dynamic model that can accurately predict the motion of the door handle and counterweight during side impact crash tests. The door locking system, mainly composed of the door outside handle and door latch, is theoretically modeled, and it is assumed that the door outer panel can rotate and translate in all three directions during a side impact crash. Additionally, the numerical results are compared with real crash video footage, and satisfactory qualitative agreement is found. Finally, the simplified test rig that efficiently reflects the real crash test is introduced, and its operation is analyzed."
Effect of Beam Layout and Specification on Side Door Strength of Passenger Cars: An Experimental Approach to Analyze Its Effect and Contribution to Door Strength.,"Risk of injury to occupant in the event of side impact is considerably higher compared to frontal or rear impact as the energy absorbing zones at the front and rear of vehicle is high whereas limited space is available to dissipate the impact energy in the event of side impact. In such scenario strength of side door plays an important role in protecting the occupant. Side door beam in door structure contributes significantly towards the lateral stiffness and plays dominant role in limiting the structural intrusion into passenger compartment. Hence it is interesting to understand the effect of beam specification and orientation on side door strength. Since these factors not only affect the strength but also the cost and weight targets, their study and analysis is important with respect to door design This paper showcases the effect of beam layout and its specifications on the overall strength of the door with an experimental approach using physical test. Beams with different specification and orientation were tested and based upon the test results; a co-relation is built with Side door intrusion test as per IS 12009"
Simulation and Physical Measurement of Seamless Passenger Airbag Door Deployment,"Seamless Passenger Airbag Door, which means the seam of the passenger airbag door is not visible to the passenger, is being frequently implemented in the instrument panel because of its good surface appearance. But it is always a challenge to design a robust passenger airbag door with an invisible seam because many kinds of failures are possible during the design, such as cracks of the substrate of instrument panel, hinge failure of airbag door, windshield breakage, etc. Besides the engineering difficulties, the simulation of seamless passenger airbag door deployment is challenging due to three aspects: 1. the simulation method of the early stage airbag deployment (0~20 msec after trigger), 2. the material model of the airbag door pre-weakening line (the invisible seam); and 3. the physical measurement of the reaction load between cushion and door. In this paper, the FPM (Finite Point Method) method in PAM-CRASH™ was used to simulate the early stage airbag deployment and the fabric material model was validated by a material sample tensile test. An airbag deployment test was designed to push a mass upwards and the acceleration of the mass was measured. The measured acceleration shows FPM method with the validated fabric material model is capable to give a good prediction of the early stage airbag deployment. The material model of door seam is also presented and validated with a physical test. To measure the reaction load between airbag cushion and door, Flexi-Force™ sensors, film-like pressure sensors, were used. To deal with the nonlinear signal output of the sensor in different pressure ranges, a calibration device was developed exclusively for this sensor. After the calibration, 32 Flexi-Force™ sensors were put into a seamless passenger airbag door on the IP structure, and then the reaction load between the airbag door and the cushion was measured in its deployment. The action point position of the resultant reaction load, its peak value and duration correlate with the physical tests. Finally, the limitations and future developments are discussed."
Study of Side Door Intrusion Test Results,"With Ever Increasing Vehicle speed and Vehicle concentration on roads the number of accidents is also increasing. Safety and Strength of Vehicle has become a prime focus in Automobile Industry. The endeavor is to make a safe vehicle which would ensure occupants safety during collision. In Automotives, door system strength plays a vital role in defining the vehicle response during accidents. These accidents through, side door intrusion test and dynamic side impact test are simulated in the vehicle development cycle. Strength of the door required to meet these test criteria is dependent on the door beam, reinforcements, beam layout, vehicle construction and materials selected. There is not a fix method for door beam selection and design. Hence, it becomes all the more difficult to design and layout door beam and other reinforcements. In this paper we will discuss, challenges faced in a layout of door beam for a new vehicle program. Limitation in use of CAE analysis for achieving actual results, and design & layout modifications to be carried out to meet side door intrusion criteria effectively."
Efficient and Light Weight Door Panels for Automobiles,"Automobile manufacturers in the developing nations tend to make more and more fuel efficient cars compared to the luxurious type, given to the popularity. Fuel efficiency has a direct relation with the weight of the vehicle. In order to increase the fuel efficiency, body weight has to be decreased. The weight of all door panels comprises about 15% of body weight of the vehicle. Hence, by reducing the weight of the door panels, fuel efficiency of a vehicle can be increased. But, reduction of the weight of the door panels may lead to decrease in the strength of the panels. Therefore, we need to find a method to increase the fuel efficiency by decreasing the weight and maintaining the strength of the door panels. The aim of our study is to increase the performance while decreasing the weight of the door panel assembly. We have used CAE (Computer aided Engineering) as a tool to study and evaluate the performance of doors, with varying thickness and different shapes like beads. We found different methods to strengthen the panels by modifying the shape. It was concluded that reduction in the weight of the door can be done by improving the shape and performance of the door."
Structure to Assist in the Prevention of Bimetallic Corrosion of Hybrid Doors,"The use of low-density materials in body panels is increasing as a measure to reduce the weight of the vehicle body. Honda has developed an aluminum/steel sheet hybrid door that is more effective in reducing weight than an all-aluminum door. Because aluminum was used in the door skin, bimetallic corrosion at the connection between the aluminum and the steel sheets represented an issue. It was possible that the difference in the electrical potential of the two metals might promote corrosion at the connection between the aluminum door skin and the steel sheet door panel, in particular at the lower edge of the door, where rainwater and other moisture tend to accumulate, with the result that the appeal of the exterior of the door might decline. To address this issue, a watertight structure realized through the use of a high-ductility sealer was employed in order to help prevent water from infiltrating to the connection between the metals, and steel sheets with a zinc-aluminum-magnesium alloy coating, highly effective in controlling bimetallic corrosion, were employed in the door panels. This produced rust-resistance specifications for the hybrid door able to maintain durability in market use environments. This paper discusses the effect of the zinc-aluminum-magnesium alloy-coated steel sheets in controlling bimetallic corrosion."
Finite Element Analysis of Door Closing Effort,"The door closing effort is one of the first impressions to customer's mind about the engineering and quality of the vehicle. The door closing force and the minimum door closing speed are two important characteristics for evaluation. But we can obtain these two indices only by experiments and/or subjective assessments. To predict the door closing effort by the simulation method during the design phase, a finite element analysis model is established. The compression load deflection behavior of seals is converted to the parameters of constitutive model of seals by the parameters identification method. Then, the seal resistance force and the minimum door closing speed are calculated. The later correlates very well with the experiment data."
A Study on the Rattle Index from a Vehicle Door Trim under Audio System Inputs,"The sound inside a passenger cabin is composed of many elements, which include irritating noises such as buzzes, squeaks and rattles. Customer perception of buzz, squeak and rattle (BSR) is measured by Things Gone Wrong (TGW), warranty claims and JD Power surveys.1) The Speaker BSR test has been adopted to evaluate and to eliminate rattle noise of a door module while playing sound through the audio system. Subjective listening had been the preferred method for rattle noise detection, due to the sound of the audio system in any measurement. In this paper a quantitative approach for the rattle noise under the speaker test is proposed. The HANIL E-HWA rattle index was developed using a high pass filter, hiss noise reduction filter, SPL data with short time constant, peak value and fluctuation. The high pass filter was adopted to separate the rattle noise from the speaker sound, due to much higher sound pressure level [108 dB(A)] in the latter case. It is then possible to quantify the rattle noise by the HANIL E-HWA rattle index based on the peak values and fluctuations of the SPL data in the speaker BSR test. This article includes test results which show the improved rattle noise detection capability of the HANIL E-HWA rattle index."
A Method of Designing Automotive Door Glass and Guide Rail based on the Drum Surface,"A new method based on the drum surface is proposed to fit the dual-curvature glass. The drum surface is obtained from the automotive body cloud data with the kinematic equation using line element geometry and K-Local-RANSAC algorithm. Then the guide rail curve is obtained by the proportional function method based on the drum curve principle. At last, the motion deviation of the glass is analyzed and the maximum motion deviation is not more than 0.6mm. The results have completely achieved the engineering requirements, which prove that the method of fitting the glass and the guide rail is correct and reasonable."
Study of Optimizing Sliding Door Efforts and Package Layout,"A sliding door is one of the car door systems, which is generally applied to the vans. Compared with swing doors, a sliding door gives comfort to the passengers when they get in or out the car. With an increasing number of the family-scale activities, there followed a huge demand on the vans, which caused growing interests in the convenience technology of the sliding door system. A typical sliding door system has negative effects on the vehicle interior package and the operating effort. Since the door should move backward without touching the car body, the trajectory of the center rail should be a curve. The curve-shaped center rail infiltrates not only the passenger shoulder room, but also the opening flange curve, which results in the interior package loss. Moreover, as the passenger pulls the door outside handle along the normal direction of the door outer skin, the curved rail causes the opening effort loss. In this study, we discuss not only how the curved center rail causes negative effects on the vehicle interior package and the manual operating effort, but also how to effectively improve and optimize the sliding door system. Moreover, we propose a new design concept of a convenient sliding door system. By applying a straight center rail and a latch with a multi-link structure, we were able to decrease the center rail infiltration. Also, the performance of getting on and off the 3rd row was improved, and the manual operating effort was improved about 60%."
Vehicle Door Inner Frame Part Design with Knowledge-Based Engineering,"In this study, a computer-aided design (CAD) geometry system that is linked to each other to create a parametric form of the side rear door’s inner frame sheet piece on a passenger vehicle body in a Siemens NX environment was developed. The system was created in the NX CAD environment, using the program’s unique product development structure. The system was designed and modified for time-consuming parts. At the end of the study, the parameterized vehicle door geometries worked in the NX environment standardized the design process and accelerated the design works."
Classification of Contact Forces in Human-Robot Collaborative Manufacturing Environments,"This paper presents a machine learning application of the force/torque sensor in a human-robot collaborative manufacturing scenario. The purpose is to simplify the programming for physical interactions between the human operators and industrial robots in a hybrid manufacturing cell which combines several robotic applications, such as parts manipulation, assembly, sealing and painting, etc. A multiclass classifier using Light Gradient Boosting Machine (LightGBM) is first introduced in a robotic application for discriminating five different contact states w.r.t. the force/torque data. A systematic approach to train machine-learning based classifiers is presented, thus opens a door for enabling LightGBM with robotic data process. The total task time is reduced largely because force transitions can be detected on-the-fly. Experiments on an ABB force sensor and an industrial robot demonstrate the feasibility of the proposed method."
Novel Glass Laminates for Improved Acoustic Performance,"Noise, Vibration, and Harshness (NVH) performance of vehicles is an all-encompassing study of hearing and feeling vibration as it relates to end user experience. The collection of glass in a vehicle can represent a large surface area, and can have a significant effect on NVH performance. Some of the most important glazing positions in relationship to the driver are the front doors, due to the proximity to the driver. Novel glass laminate constructions can provide acoustic improvement for these body positions over typically used standard glazings. The performance of these constructions will be discussed in terms of: acoustics, glass closing and door slam survivability, and solar performance."
Research on Intelligent Layout of Door Hinge Based on CATIA CAA,"As one of the most important auto-body moving parts, door hinge is the key point of door design and its accessories arrangement, also the premise of the door kinematic analysis. We proposed an effective layout procedure for door hinge and developed an intelligent system on CATIA CAA platform to execute it. One toolbar and five function modules are constructed - Axis Arrangement, Section, Parting Line, Kinematic, Hinge Database. This system integrated geometrical algorithms, automatically calculate the minimum clearances between doors, fender and hinges on sections to judge if the layout is feasible. As the sizes of the clearances are set to 0s, the feasible layout regions and extreme start/end points are shown in parts window, which help the engineer to check the parting line and design a new one. Our system successfully implemented the functions of five modules for the layout of door hinge axis and parting line based on a door hinge database. An instance is carried out and the result shows that our system has great feasibility and validity to arrange the door hinge and shorten the design periods."
Door Closing Sound Quality Methodology - Airborne and Structural Path Contributions,"The intent of this paper is to document comprehensive test-based approach to analyze the door-closing event and associated sound using structural and acoustic loads developed during the event. This study looks into the door-closing phenomenon from the structural interaction point of view between the door and the body of the vehicle. The study primarily focuses on distributing the door and body interaction as discrete multiple structural and acoustic phenomena. It also emphasizes on the structural and acoustic loads developed by the discretized interactions at the interfaces between the door and the body frame. These interfaces were treated to be the load paths from the door to the body. The equivalent structural and acoustic loads were calculated indirectly using the well-known Transfer Path Analysis (TPA) methodology for structural loads and the Acoustic Source Quantification (ASQ) methodology for acoustic loads. Considering the transient nature of the door-closing event, a time domain TPA methodology was also developed to study the loads being developed between the latch, the striker and the different interfaces of the door frame to the body structure. Similarly the equivalent acoustic loads were developed at the interfaces between the door frame and the body. Computed time domain and frequency domain loads were used to perform a partial contribution analysis from different paths and identify the contribution of the structural and acoustic loads and paths on the target response at the center of the operator's ear (COE) located the outside of the vehicle."
Five Bonding Techniques of Side Door Trim Insert Skin Decoration,"Interiors of past vehicles were created to satisfy specific functions with appearance being a secondary consideration, but in the present & future market with ever increasing vehicle luxury, decoration of vehicle has become a prime focus in automobile industry along with the safety & economy. Automotive interiors have evolved over the years from a collection of trims covering bare sheet metal panels to add quality & richness of interior cabin, ultimately delivering greater value to customers. One such area in interiors is Side door trims serving the dual purpose of functionality and creating a pleasing environment too. The aesthetic appeal to the Side door trim is added usually through a Door trim insert having a decorative skin pasted on to the plastic base. And the selection of pasting technique for pasting decorative film on to the plastic base insert is a challenge for an automotive interior designer. The objective of this paper will be to review technologies available for manufacturing Door trim inserts with decorative skins, and discuss a direction toward selecting an appropriate pasting technique with cost effectiveness. In automotive industry, for Side door trim insert decoration, five bonding techniques are used ranging from Adhesive pasting, Thermo compression molding using natural fiber reinforced PP, Pressure lamination, Kimikomi, and Low pressure injection molding, all these will be discussed in this paper. A brief synopsis of the advantages and disadvantages of each process including cost effectiveness, design considerations, shape & complexity of Door trim inserts, Door trim insert skin types & their physical property requirements, process considerations and its testing methods are covered. In addition to this, the necessary tooling investment will also be discussed in this paper."
A Component Test Methodology for Simulation of Full-Vehicle Side Impact Dummy Abdomen Responses for Door Trim Evaluation,"Described in this paper is a component test methodology to evaluate the door trim armrest performance in an Insurance Institute for Highway Safety (IIHS) side impact test and to predict the SID-IIs abdomen injury metrics (rib deflection, deflection rate and V*C). The test methodology consisted of a sub-assembly of two SID-IIs abdomen ribs with spine box, mounted on a linear bearing and allowed to translate in the direction of impact. The spine box with the assembly of two abdominal ribs was rigidly attached to the sliding test fixture, and is stationary at the start of the test. The door trim armrest was mounted on the impactor, which was prescribed the door velocity profile obtained from full-vehicle test. The location and orientation of the armrest relative to the dummy abdomen ribs was maintained the same as in the full-vehicle test. An aluminum honeycomb of a pre-determined crush strength and cross-sectional area attached to the base of the assembly of two abdominal ribs was used to simulate the lumbar shear force, to capture the effect of lower torso loading on the upper torso. The test methodology was developed and validated to a full-vehicle test and the sensitivity of the methodology to different armrest designs was also evaluated. The results show good correlation to full-vehicle test, thus indicating that this component test methodology has good potential to evaluate different armrest design alternatives across various vehicle programs."
An Experimental Study on Flow Pattern of Door Trim Speaker Grille Shape,"Recently the automotive industry has focused on reducing product development time to correspond with the customer's demands. Especially when quickly changed. The decreased product development time shortens the quality assurance period. It makes difficult to guarantee the quality of the products. The improved quality assurance is required so that customer's expectations are actually higher quality than in the past. Most automotive interior parts are manufactured by using plastic. It is very sensitive to focus on quality, because it is exposed to a passenger's sight. So automotive interior companies make full use of injection molding CAE in an effective ways to reduce costs and reduce elements of poor quality. This paper suggests a methodology that improves reliability for injection molding analysis in grille shapes of door trim. And it involves an experimental analysis of flow pattern in speaker grille shapes. To analyze it, use an authentic mold of speaker grilles in door trim and Mold flow software."
CAE Simulation of Door Sag/Set Using Subsystem Level Approach,"The performance of door assembly is very significant for the vehicle design and door sag/set is one of the important attribute for design of door assembly. This paper provides an overview of conventional approach for door sag/set study based on door-hinge-BIW assembly (system level approach) and its limitation over new approach based on subassembly (subsystem level approach). The door sag/set simulation at system level is the most common approach adopted across auto industry. This approach evaluates only structural adequacy of door assembly system for sag load. To find key contributor for door sagging is always been time consuming task with conventional approach thus there is a delay in providing design enablers to meet the design target. New approach of door sag/set at “subsystem level” evaluates the structural stiffness contribution of individual subsystem. It support for setting up the target at subsystem level, which integrate and regulate the system level performance. This approach is also useful for generating the design enablers and for optimization of door-hinge-BIW assembly with higher reliability. The commercial software “ABAQUS STANDARD” is used as FE solver to simulate the door sag/set by both the approaches with application of material, geometrical and contact nonlinearities."
Experimental Approach to Improve the Door Slam Noise Quality in Utility Vehicles,"The customer perception about the door slam noise and its feel would indicate the brand image of the car. In this paper the authors have made an effort to improve the door slam noise quality of the vehicle, which is currently in production. This paper describes the probable areas in the door to improve the slam noise quality by attempting modifications in the door design factors, such as door alignments, door panel stiffness, door trims, window glass rattle, latch striker alignment, door seals, air extractor. Since the door closing event is a transient phenomenon, it requires special tools such as wavelet transforms, Zwicker loudness to understand the slam events precisely. Subjective jury evaluations have been conducted to understand the effect of these modifications and rank the modifications based on their contributions to the door slam quality."
French Door Open/Close Durability Evaluation by Multibody Dynamics Method,"A method including Multi-Body Dynamics (MBD) and fatigue assessment process with modal approach was developed to predict Light Commercial Van (LCV) Rear French Doors open/close durability performance during early design stage to improve test detect ability. The nonlinear properties of joints, such as those on bolted housings or spot welds sheets and hem flange areas, can substantially influence the local and global results of a dynamic simulation. The Modal approach considers joint contact, by way of Joint Interface Modes (JIMs) by using Contact Subroutine (MAMBA) to co-simulate with MBD software to improve result quality. One of the main challenges is measuring the dynamic stiffness for the weather strip. A novel test method was used to measure the weather strip dynamic stiffness by conducting an “in-situ” test. For CAE simulation results, positive feedback was received from design and test engineers."
Study of the Energetic Influence of Each Component Responsible for Closing the Side Doors,"Currently, studies are being developed by automobile engineers about the energy required by the client during the closing door of the car. This paper proposes an analysis of A segment vehicle, four doors, in order to evaluate the influence of each component of the door/body responsible for closing the side doors. Tests will be carried out to demonstrate exactly the contribution of the door sealing, exhaust air valve and the inner cabin air pressure effect, door link, hinges and latch, plus the actual weight of the door during the closing. The results show which are the door/body components most responsible for car door closing movement energy increase and still, where to direct efforts to provide greater comfort for customers."
Integration and Lightweight Design in Automotive Doors,"Future doors require light weight, cost efficient and acoustic optimized solutions. Current steel doors offer only a small range of possibilities in these areas. With the use of aluminum doors the weight will be reduced but production complexity and costs will be increased. A modular door approach supports all of these future demands. Door modules have set milestones for door concepts in the past. Due to technological progress, door modules are more relevant in the current scenario. The use of reinforced plastics allows a high degree of design freedom with high integration of features.[2] In addition to weight reduction of up to 1.5kg per door the complete production process comes leaner with a higher grade of quality. The acoustic performance of a door system can be adjusted for noise reduction and improvement of the sound quality of speakers as illustrated. Functional integration is the key driver of weight and cost reduction"
A Study on Prediction of Door Deformation in High Speed Passenger Vehicle at Cross Wind,"In this study, several design factors are considered to predict door deformation. Door deformation is mainly influenced by air flow around A-pillar and door static stiffness. Therefore design factors can be divided into two categories. First, design elements determined by the appearance of a car affect to the air flow around A-pillar. Second, door static stiffness is determined by engineering design parameters. Kriging method is used to predict door deformation by means of the design factors. Door deformation can be successfully predicted with this method."
Modelling and Simulation of Door Control System,"A Door Control System is being used for controlling doors in buses running in urban/suburban areas as a part of safety requirement and to protect the passengers. The opening and closing of the doors will be in logical sequence depending upon the driver input, vehicle speed and the emergency conditions. To achieve this logic the door control system consists of an ECU, pneumatic valves, pressure sensors and switches. To predict the performance of this system under various operating conditions, the entire system is being modeled in one of the commercially available multi-domain physical modeling software employing bond graph technique and lumped system and the performance is predicted. This paper deals with the modeling and simulation of entire Door Control System."
Investigation of Relation between Sub System Level (Quasi-Static) Side Door Intrusion to Side Collision Test,"With the change in the perspective of the Customers towards safer vehicles, most of the Vehicle manufacturers in India are making their vehicles Crash compliant. According to the accidental data collection, Side crashes are second leading cause of death after Frontal crash. Currently sub system level tests are done for evaluating the side impact safety performance of the vehicle. One of such sub system level test is Quasi-static side door intrusion Test. The primary purpose of this testing is to measure the Force-deflection characteristics by intrusion of the impactor into the vehicle. These characteristics are controlled by various door components like door beam, latch & striker, hinge etc. This article studies the relation between Side door intrusion and Side collision, effect of above mentioned components on this relation. A theoretical study is done to study this relationship and it is substantiated with experimental data."
Study of Sliding Door Closing Speed for a Manually Operated Sliding Door,"The door performance of an automobile is gauged not only by its function but also the “feel” of operating a door which majorly depends upon opening/closing force and closing speed. This feel is in direct relation to the soundness of design and the build quality which the customer experiences even before driving the vehicle. Several studies have been conducted for door open/close performance for a conventional swing door, however little has been done in direction of sliding door. In this paper an analysis of closing speed of manually operated sliding door in purview of various parameters affecting them and their individual and combined contribution at vehicle level is presented. As the closing locus of sliding door is different from a swing door, a special experimental setup is used to measure the closing speed of sliding door."
MMLV: Door Design and Component Testing,"The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The Mach-I vehicle design, comprised of commercially available materials and production processes, achieved a 364kg (23.5%) full vehicle mass reduction, enabling the application of a 1.0-liter three-cylinder engine resulting in a significant environmental benefit and fuel reduction. This paper reviews the mass reduction and structural performance of aluminum, magnesium, and steel components for a lightweight multi material door design for a C/D segment passenger vehicle. Stiffness, durability, and crash requirements are assessed. The structure incorporated aluminum sheet, aluminum extrusion, magnesium high pressure vacuum die casting and steel sheet. The multi material components were assembled using structural adhesive bonding (hem and structure), self-pierce rivets (SPRs), single sided rivets, and bolts. The aluminum extrusion and the magnesium casting in the MMLV door were specifically designed to maximize stiffness, reduce part count and maximize mass reduction. To optimize the strength and weight of the MMLV door, a new aluminum intensive structure was developed. The new structure features a unique architecture that uses a multi-cavity aluminum extrusion joined to stamped sheet reinforcements to provide a direct load path between the hinges and the latch. The new structure also utilizes a high pressure vacuum die cast magnesium casting to create the structure at the base of the A-pillar on the front door to achieve the required structural stiffness while reducing components and maximizing the mass reduction. The “barn door” architecture of the inner structure of the door allowed for gage optimization of both the inner and outer stampings, the two largest and heaviest components of the assembly. Overall, the design architecture used in the MMLV doors allowed for a mass reduction of 33% through the use of multi material, gage optimization, and multiple forming technologies, while achieving all of the structural requirements."
Numerical Study of Effect of Material and Orientation on Strength of Side Door Intrusion Beam,"Nowadays more and more people are concerned about the safety rating of their vehicle. The safety rating depends on the ability of the car to minimize the injury to the occupants post-crash. Crashworthiness of the vehicle is determined by carrying out various tests such as static and dynamic tests. Side crashes are one of the leading causes of fatal injury following front crashes. Side door strength is dependent on the door components such as latch and striker, hinge, door beam etc. Lateral stiffness is contributed significantly by the side door beam in the door structure. The side door beam limits the side intrusion into passenger compartment. This paper emphasizes the effect of intrusion beam materials and orientation in the side door strength with a numerical approach using ANSYS tool. These factors affect the strength and weight of the door. The simulation study with respect to door design is cost-effective and time-saving. Side door intrusion test as per IS 12009 norms is simulated in the software and are substantiated by the experimental test results of existing literature."
Vehicle Door Cutline Determination with Mathematical Modelling on CATIA V5,"Door shut-line definition is the first vital step in car body door engineering and depends on the hinge position, hinge shape, manufacturing capabilities and other parameters. In the design process, once the hinge axis definition is finalized door shut-line is defined which should satisfy two major requirements. The requirements are clearance between the door outer surface with its surrounding components (like hinges, fender, other door etc.) and assembly feasibility. Another one is the manufacturability of the proposed design. The above conditions must be checked on different locations of the door as well as w.r.t different openings of the door. The paper presents a mathematical model to determine the door shut-line position with great computational efficiency. This method propounds closure engineer with parameters to define the shut line rather than going for cumbersome manual iterative process. Instead of following an iterative approach to determine a limit for the shut-line, paper presents a mathematical formulation with an implicit equation. An innovative approach to solve implicit equation on CATIA is also discussed which significantly reduces the processing time. This paper inherently discusses a series of challenges which a user faces while determining the door shut-line and provides feasible solutions for those problems."
CFD-Simulation and Validation of Cabin Pressure during Door Closing Motions,"Under the competitive pressure of automotive industry the customer’s focus is on a vehicle’s quality perception. Side door closing efforts make a considerable share of the overall impression as the doors are the first physical and haptic interface to the customer. Customer’s subjective feeling of vehicle quality demands for detailed analysis of each contributor of door closing efforts. Most contributors come from kinematic influences. Beside the losses due to mechanical subsystems like the checkarm, latch or hinge friction one of the biggest impacts originates from the pressure spike that builds up due to air being pushed into the cabin. Subject of this publication is to discuss the dependencies of closing efforts on cabin pressure and air extraction. It demonstrates an approach to simulate the development of the air pressure during door closing motions and the validation of the simulation method with the “EZ-Slam” measurement device. In order to produce a correlation between simulation and reality a simplified model of a vehicle cabin is created. The validation tests are conducted on a physical test rig, built exactly according to the model, and the CFD simulation is done on the CAD model of the rig. In order to show a correlation between the CFD method and the physical test procedure a set of influencing parameters is identified and tested for its impact on the pressure spike."
An Optimal Design of Vehicle Swing Door Using Metamodeling Techniques,"In side-closures’ design, mass reduction provides numerous benefits in addition to reduced cost. This paper presents a Meta model based non-linear durability optimization to develop a lightweight structure for vehicle swing door. A surrogate model developed is using Kriging methodology and the thickness of the door components are given as input design variables. Adaptive Multi-Objective Genetic Algorithm (AMGA), a nonlinear optimization technique, is used in this study, to formulate the mass minimization under durability constraints. The optimized swing door design shows the overall mass saving of ~10% over initial design in terms of frame and sag deflection. The present investigation shows better effectiveness and practical applicability to develop the lightweight structure for the vehicle swing door. From the comparative study, Kriging method is found to be more effective in terms of measuring the accuracy, robustness and efficiency of the results than the Radial basis function (RBF)."
Development of the Wireless Power Transfer Technology for a Sliding Door,"The sliding door’s movement is 3-dimensional unlike the conventional door. So the electric power and signal are exchanged via the long ‘Power Cable’. It has a quite complex structure in order to be suitable to connect the vehicle’s body and the sliding door even during it’s moving. As the result, it is more expensive than conventional door’s one and the quality could not be guaranteed easily. In this paper, I have developed new technology which could transfer electric power by ‘wireless transfer’ in order to resolve the problem from using ‘Power cable’. I would propose the proper structure to transfer the electric power at any position of the sliding door without any physical connection. To transfer the electric power which drives the window regulator and the actuators in door, I have applied the ‘inductive coupling’ system. And in order to decide the engineering properties - such as the dimensions of the core, the values of the electric elements and the frequency of the transferred electricity - a myriad of computer analysis and experiments under various conditions would be implemented. Finally, the optimal solution was figured out and it was validated under the real vehicle’s condition. This research would be adopted in various types of the future door system."
A Study on Door Clips and Their Influence on BSR Performance,"Squeak and rattle concerns account for approximately 10% of overall vehicle Things Gone Wrong (TGW) and are major quality concern for automotive OEM’s. Objectionable door noises are one of the top 10 IQS concerns under any OEM nameplate. Door trim significantly contributes to overall BSR quality perception. Door trim is mounted on door in white using small plastic clips with variable properties that can significantly influence BSR performance. In this paper, the performance of various door clips is evaluated through objective parameters like interface dynamic stiffness and system damping. The methodology involves a simple dynamic system for the evaluation of the performance of a clip design. Transmissibility is calculated from the dynamic response of a mass supported by clip. Parameters such as interface stiffness and system damping are extracted for each clip design. Variation of inner panel thickness is also considered when comparing clip performance. In a second step, clip characteristics are transferred to an equivalent finite element model to predict the response of mass supported by clip. The equivalent clip model is compared with generic clip model for analyzing squeak and rattle simulation in a door assembly. A satisfactory correlation has been achieved between measured and simulated response of clip. Design targets are finally presented for the selection of door clips in the product development process, to avoid rattle issues in door trim assemblies."
Door Closure Sound Quality Engineering Process,"An important factor contributing to a customer’s subjective perception of a vehicle, particularly at the point-of-purchase, is the sound created by the passenger doors during closure events. Although these sounds are very short in duration the key systems that control the sounds produced can be highly coupled. Similarly, the necessary efforts required to understand key design criteria affecting the sound can also be highly complex. Within this paper sub-systems affecting the door closure sound are evaluated to understand key structural properties and behaviors toward the contribution to the overall sound produced. This begins with the subjective preferences of typical sounds and the difficulties with both measuring and reproducing these sounds appropriately and leads directly to the target setting and target cascading process. With targets in place, it becomes important to link them with physical measurements of the vehicle and door system to identify the key controlling mechanisms that can be affected through design. The behavior of the door system during a closure event is key for the sound produced and can be studied to understand both the nearfield acoustic field generated as well as the structural vibration patterns. This can be accomplished during a closure event and linked to in-lab assessments that allow for greater repeatability and flexibility. Boundary conditions for the door structure are also relevant to the sound produced, including the transmission of forces into the seals, latch and striker, and bump-stops, as well as understanding the effects from the vehicle interior cavity. Once the key controlling mechanisms affecting the door closure sound quality are understood, it allows for the sound produced to be shaped as desired. This can be accomplished by leveraging analytical modeling efforts, supplemented with necessary test data, to design key components and systems to achieve the desired sound."
Sound Quality Prediction Modelling for the Transient Sound of Vehicle Door Latch Closure,"Door latch closure noise has contribution on sound quality of vehicle door slam sound. This paper focuses on the modelling of sound quality for door latch closure sound. 24 various latch closure sound samples were recorded to be evaluated subjectively. A novel Dynamic Paired Comparison Method (DPCM) was introduced for subjective evaluation. By eliminating the redundant comparison pairs the DPCM dramatically reduced the evaluation work load comparing to the traditional Paired Comparison Method (PCM). Correlation between subjective evaluation results and psychoacoustic metrics was analyzed to find out the most relevant metrics as inputs for the subsequent prediction model. Besides, the shudder effect induced by multi-impact of latch components during closing movement was also found strongly affecting the subjective perception of door latch closure sound. Therefore, a new metric Shudder Level which is graded in 3 levels describing this shudder effect was developed and then quantified as one of the model inputs. The sound quality of door latch closure was modeled by means of Multi-Linear Regression Function (MLRF) both with and without the Shudder Level. The results show that the model which takes the shudder effect into account gives a better prediction on door latch closure sound quality."
The Analysis and Control of Aural Discomfort inside a Car at the Instant of Door Closing,"With the continuous improvement of vehicle air leakage performance, an aural discomfort phenomenon had been occurred at the instant of vehicle door closing. There are many studies on door closing sound quality in past 20 years, but there is little publications on the study of the aural discomfort due to a transient high air pressure fluctuations. In this paper, the relationships of passenger’s aural discomfort produced by interior air pressure fluctuations are systematically studied. The ratio of door surface area to passenger compartment volume and other related parameters such as the cross-sectional area of a vehicle, the air extractor size, and the vehicle body air leakage under positive pressure are also studied through CAE analysis and verified through a large number of objective measurements and subjective vehicle evaluation. Base on this study, a new threshold value of air pressure fluctuation for human aural comfort, and a new objective evaluation index for aural discomfort due to the transient air pressure fluctuations are defined. Some guidelines for the pressure exhaust system design and development to improve the door closing aural comfort of passenger vehicles are provided."
A Robust Methodology to Predict the Fatigue Life of an Automotive Closures System Subjected to Hinge and Check Link Load,"In order to provide an accurate estimation of fatigue life of automotive door hinges and check strap mounting location, it is crucial to understand the loading conditions associated with opening and closing the door. There are many random factors and uncertainties that affect the durability performance of hinge and check strap mount structures in either a direct or indirect way. Excessive loads are generated at the hinge and check arm mounting region during abuse conditions when opening the door. Repeating the abuse conditions will lead to fatigue failures in these components. Most influencing parameter affecting the fatigue performance for the door was the loads due to hinge-check arm sensitivity stoppage and the distance between hinge and check strap attachments. However, the probability of occurrences was low, but the impact is high. In this proposed investigation, Monte Carlo simulation methodology is applied on the randomly selected samples with predicted distribution of all dependent factors to know the fatigue life variations in the hinge mount structure. Weibull distribution is the most efficient way of estimating the fatigue failure or fatigue life. This can be estimated on the basis of the function of the populated size. The mean and standard deviation of the simulated fatigue life converged with a greater number of randomly varied samples. This technique defines the maximum allowable load cycles on the hinges and the check arm mount structure, and their variability. It helps in keeping the door opening efforts below the target value. The fatigue life cycle of the door is predicted closest to the experiments by applying the proposed method on more number of samples. It also keeps the probability of failure under check"
A Study on Optimization of the Cross-Section of Door Impact Beam for Weight Reduction,"This paper focuses on the optimization of the cross-section of a panel type impact door beam. The key parameters of the cross-section of the beam were artificially changed by using a geometry morphing tool FCM (Fast Concept Modeler), which is plugged in to CATIA. Then, the metamodel of FE (Finite Element) analysis results was created and optimized using LS-OPT. The ANOVA (Analysis of Variance) analysis of results was carried out to find the factor of weight reduction. Finally, a new cross section concept was proposed to overcome the limitation of old structure. The optimization was carried out for the beam with the final cross-section to have 10 % or more reduction in total weight."
A Research on Kinematic Optimization of Auto Flush Door Handle System,"Today, many car manufacturers and their suppliers are very interested in power-operated door handles, known as auto flush door handles. These handles have a distinguishing feature in terms of the way they operate. They are hidden in door skins and deployed automatically when users need to open the door. It is obvious that it is a major exterior styling point that makes customers interested in the vehicles that apply it. To make this auto flush door handle, however, there lie difficulties. First, because there is no sufficient space inside a door, applying these handles can be a constraint in exterior design unless the structures of them are kinematic optimized. The insufficient space can also cause problems in appearance of the handles when they are deployed. The purpose of this study is to establish the kinematic system of auto flush door handle to overcome the exterior handicaps such as the excessive exposure of the internal area on the deployed position. In order to resolve these issues, the Scott-Russell mechanism is applied to the auto flush handle system, and the key parameters are optimized by the methodology of DFSS dynamic characteristics method. Therefore, the engineering solutions are given to resolve the finger jamming in the handle due to the high speed retraction and the incongruity of the relative retraction speed between the handle and outside mirror. Thus, in this paper, the engineering solutions and optimized criteria to resolve all related issues are introduced to enhance the values of vehicles for customers."
Robust Assessment of Automotive Door Structure by Considering Manufacturing Variations,"The automotive door structure experience various static and dynamic loading conditions while going through an opening and closing operation. A typical swing door is attached to the body with two hinges and a check strap. These mechanisms carry the loads while the door is opened. Similarly, while closing the door, the latch/striker mechanism along with the seal around the periphery of the door react all loads. Typically, computer aided engineering (CAE) simulations are performed considering a nominal manufacturing (or build) tolerance condition, that results in one loading scenario. But while assembling the door with the body, the build variations in door mechanisms mentioned above can result in different loading scenarios and it should be accounted for design evaluation. This paper discusses various build tolerances and its effect on door durability performances to achieve a robust door design."
CAE Simulation of Automotive Door Upper Frame Deflection Using Aerodynamic Loads,Upper frame deflection of automobile doors is a key design attribute that influences structural integrity and door seal performance as related to NVH. This is a critical customer quality perception attribute and is a key enabler to ensure wind noise performance is acceptable. This paper provides an overview of two simulation methodologies to predict door upper frame deflection. A simplified simulation approach using point loads is presented along with its limitations and is compared to a new method that uses CFD tools to estimate aerodynamic loads on body panels at various vehicle speeds and wind directions. The approach consisted of performing external aerodynamic CFD simulation and using the aerodynamic loads as inputs to a CAE simulation. The details of the methodology are presented along with results and correlation to experimental data from the wind tunnel.
Evaluation of Energy Efficiency Performance of Refrigerated and Heated Van Semitrailers,"The objective of this project was to provide pertinent information on the performance of refrigeration and heating transportation units to help fleets make decisions that will improve efficiency and increase productivity. To achieve this objective, tests were designed to measure the performance of selected refrigeration and heating units, mounted on refrigerated and heated van semitrailers. Cooling and freezing tests were carried out in summer conditions while heating tests were carried out in winter conditions, for various temperature settings. Two fundamental approaches were considered: the design of the refrigerated or heated trailer and the temperature setting of the refrigeration or heating unit. For cooling and freezing tests, the fuel consumption comparison between similar trailer models of different ages showed that newer units performed better than older ones. However, other factors such as trailer design, presence of a ventilation system, and type of insulation may also influence fuel consumption of such units. For refrigerated trailers of the same make and of similar age, those with swing doors performed better than those with roll-up doors with regards to both fuel consumption and insulation. For trailers with the same make of refrigeration unit, those without side doors performed better than those with side doors. For heating tests, it was observed that newer heated trailers with composite or insulated doors generally consumed 1.5 to 3 times less fuel then the older trailers with wood or metal doors. The tests confirmed that the interior temperature setting has a significant impact on the fuel consumption of the refrigeration or heating unit when the difference in set temperature is considerable."
Effect of Hinge Axis Inclination and Hinge Tolerance on Door Strength under Abuse Loads,"As revealed from J. D. Power surveys, today most vehicle owners consider perceived quality as a direct indicator of the vehicle build quality and durability. [5] The problem has become more prominent and noticeable in recent times, due to the desire for reduced cost, reduced weight targets, aesthetic demands, and crash requirements. The performance of the door assembly when subjected to an abuse load of sag and over opening is one such perceived quality indicator which gives the customer the first impression about the engineering and build quality of the vehicle. Door hinge inclination and hinge contact flushness tolerance are the major design parameters affecting this performance. Although these are an important design parameter, the precise quantification of the effect of these design parameters on door performance under abuse loading has remained somewhat elusive. Traditionally, this assessment was done using physical testing, thumb rules and best practices rather than using computer aided techniques. However with the automotive industry moving towards higher durability targets, reduced product cycle time and lower design costs, the need for virtual simulation has increased. The scope of this paper includes, study of load distribution on the top and bottom hinge pair of the door under over opening abuse load due to hinge contact flushness tolerance and the effect of change in door axis inclination on the door performance under door sag abuse loading. The Finite Element Modelling (FEM) techniques, boundary conditions and the interpretation of the changes in design parameters on the door assembly performance under sag and over opening loading are detailed in the subsequent discussion."
Magna’s New Ultralight Door - A Comparative LCA Study of the Lightweight Design as per ISO 14040/44 LCA Standards and CSA Group LCA Guidance Document for Auto Parts,"In response to ever more challenging global fuel economy and environmental regulations, automakers will rely on lightweighting to continue to meet the established goals. As “bolt-on” subassemblies, closure panels provide a unique opportunity to tailor the vehicle mass to achieve local environmental compliance relative to a global vehicle platform while maintaining equivalent functionality and safety performance. This paper is aimed at communicating the results of a life cycle assessment (LCA) study which compares the lightweight auto parts of the new Magna’s Ultralight Door design to the conventional auto parts of the baseline 2016 MY Chrysler 200C 6 cyl, 3.6 L, automatic 9-spd, an ICE vehicle (gasoline fueled) built and driven for 250,000 km in North America (NA) [1]. Magna International Inc. (Magna), in cooperation with the United States Department of Energy (U.S. DOE) and partners FCA US LLC (FCA US) and Grupo Antolin, developed a new ultralight door architecture in 2017 that achieved around 40% overall mass reduction compared to the baseline door. Magna’s Ultralight door LCA study is conducted in accordance with International Organization for Standardization (ISO) standards 14040/44 and follow the specific rules and guidance provided in the CSA Group 2014 LCA Guidance document for auto parts [2, 3, 4]."
Optimal Study on the TL of Automotive Door Sealing System Based on the Interior Speech Intelligibility,"Wind noise becomes the foremost noise source when a car runs at high speeds. High frequency characteristics of wind noise source and effective performance of seal rubbers for insulating leakage noise make research on the Transmission Loss (TL) of automotive door sealing systems significant. The improvement of TL of automotive door sealing system could effectively decrease the interior noise due to wind noise for vehicles at high speeds. In this study, compression simulation of seal rubbers for an automotive door is performed through a Finite Element (FE) tool firstly. Compressed geometries of the seal rubbers are obtained. Then, based on the final compressed geometries and pre-stress modes of the automotive door seal rubbers, the TL of the whole door sealing system is acquired by hybrid Finite Element - Statistic Energy Analysis (FE-SEA) method. The fluctuating surface pressure on a car body was captured by a Computational Fluid Dynamics (CFD) tool. The wind noise source is obtained by the Corcos model and the Boundary Element Method (BEM). A full vehicle SEA model is built to predict the interior sound pressure level. The TL of the automotive door sealing system is included in the full vehicle SEA model. After the SPL in the car is obtained by SEA simulation, the Articulation Index (AI) is calculated. Finally, the TL of the automotive door sealing system is optimized by orthogonal design of experiment based on AI. This integrated approach can be used to optimize TLs of automotive door sealing systems."
Research on Stick & Sprag-Slip Phenomenon of Door Waist Belts,"The squeak noise generated during the moving of the door glass has a influence on the performance of vehicles felt by the consumer. In order to improve the noise, it is necessary to understand the principle of a friction vibration. In this paper, it is confirmed that the principle on the waist belt is most closely related to stick-slip and sprag-slip among various vibration characteristics. Stick-slip is expressed by energy accumulation and divergence due to difference in static and dynamic friction coefficient. Sprag-slip define instability of geometric structure due to angle of lips on the belt. In this paper, the physical model and the energy equation are established for the above two phenomena. Stick-slip can be solved by decreasing the difference of the static and dynamic friction coefficient. Sprag-slip is caused by the ratio of compressive and shear stiffness of the lips. The belt uses flocking to ensure durability, not coating. Therefore five factors that can be considered in the production of flocking are selected such as thickness. This study introduces an approach to improve the noise using DFSS. To predict the sprag-slip, the lips was modeled by a spring-damper system, and the stiffness value could be derived by applying shear deformation after compression load. The shapes of the lips were designed with 18 cases and the guide for the optimum was provided. It is found that positional deviation occurs due to the equilibrium of forces rather than merely by the tolerance when the glass of the vehicles can be moved from 0 to 2.6 mm. The optimization was confirmed that no squeak noise occurred even under the condition of 3 mm."
Bumper on Striker: Improve Customer Perception Regarding Door Closing Sound Quality,"Did you had opportunity to hear any unpleasant noise when closing some vehicle door? In some cases reminds a metallic touch condition, in other cases reminds several components loose inside the door. The fact is that this kind of noise is definitely unpleasant to the human ears. The good news is that this undesirable condition can be solved easily through of add a soft bumper in the striker; however, needs to pay attention in the material properties and tolerance stack-up conditions to avoid generate side effect, like as high door closing efforts, break parts, lose parts, etc."
Drivmatic® Automatic Fastening System with Single Robot Positioner,"The focus of this technical paper is a unique automatic fastening system configuration for loading, positioning & unloading pre-tacked door assemblies within a static C-Frame Drivmatic® fastening machine using an off-the-shelf, high accuracy Fanuc robot. In 2011, PMC was awarded a significant contract for supplying commercial OEM aircraft doors and recognized automation was the most feasible approach for fastening each door assembly. At the time of contract award, PMC was an established aero structure supplier with significant automation capability for machining high tolerance parts & assemblies and manual fastening resources to support many different OEM programs however PMC did not have automatic fastening experience or capability. In support of this new Tier-2 contract, PMC reached out to Gemcor to propose a collaborative robot solution for automatically fastening 5 different door assemblies that were historically fastened using a semi-automatic configuration. Demand for quality rivet & Hi-lok installation, preventing rework, fast throughput and avoiding a foundation paved the way for Gemcor to develop a lean approach for fastening some of the most challenging and labor intensive aero structure assemblies."
Ultra-Light Weight Automotive Door: Design and Validation,"An Ultra-Light Door (ULD) has been developed that is 40% lighter than a baseline 2016 mid-size vehicle’s driver side door. The ULD scope encompasses the entire door, including the door-in-white (DIW), interior trim, glazing, hardware, wiring, etc. To achieve such a substantial mass reduction while still meeting the baseline vehicle’s performance metrics (including safety, durability, NVH, appearance, etc.) at a minimal cost increase, the door design relies on a comprehensive full system approach that includes a unique architecture in addition to lightweight materials and components. This paper details the ULD design concept, simulated performance results, the current status of vehicle level validation, and comparisons between component level CAE predicted performance and physical test results."
Numerical Simulation Research on Pressure during Door Closure of Commercial Vehicle,"The magnitude of door closing force is important in vehicle NVH characters, and in most case, it is not fully studied by computer aided engineering (CAE) in an early developing stage. The research took a heavy-duty truck as the study object and used Computational Fluid Dynamic (CFD) method with dynamic mesh to analyze the flow field of the cabin during door closing process. The change trend of pressure with time was obtained, and the influence of different factors was studied. The experiments were conducted to verify the results. Results show that the velocity of closing door and the size of relief holes have a significant influence on cabin interior pressure, and greater velocity leads to larger the pressure in cabin. The initial angle of the door affects interior pressure less comparing with the velocity of closing door. The interior pressure could be reduced effectively with the method of decreasing the velocity of closing door and increasing the size of relief holes."
Using Air Walls for the Reduction of Open-Door Heat Losses in Buses,"A vital contribution for the development of an environmental friendly society is improved energy efficiency in public transport systems. Increased electrification of these systems is essential to achieve the high objectives stated. Since the operating range of an electrical vehicle is heavily influenced of the available energy, which primarily is used for propulsion and thermal passenger comfort, all heat losses in the vehicle systems must be minimized. Especially for urban buses, the unwanted heat losses through open doors while passengers are boarding, have to be controlled. These energy fluxes are due to the large temperature gradients generated between in- and outdoor conditions and to install air-walls in the door opening areas have turned out to be a promising technical solution. Based on air-wall technologies used for climate control in buildings, this paper presents an experimental investigation on the reduction of heat losses in the door opening of urban buses. Devices for creating the air-wall were located on top of the door opening of an articulated bus of Dresden public transport service DVB AG. Measurements of temperatures were conducted using distributed NTC-sensors. An extensive measuring program was performed and it was found that the air walls had a significant influence on the energy exchange process. On a short door opening time the energy losses increased, while for longer door opening times major reduction on the energy losses were achieved."
AUTOMOTIVE DOOR CLOSING EFFORTS STUDY,"The door is the first system to interact with the customer, allowing the entrance into the vehicle, so it has been given great importance to its performance in all requirements. The automotive door related phenomena studies increased in the past years, once the customer and the market itself have changed their quality standards. The door closing effort is considered a quality issue by the customer, cases it is too high it contributes to quality decrease, based on ergonomics study, each OEM specifies to each vehicle an acceptable value for the closing effort. There is software that uses the finite element method and specific calculation plans for the door closing effort at project phase, but it is necessary lots of data usually not available for the engineer at concept phases. This study's objective is to measure each component contribution in door closing effort with the use of a simplified plan in order to help the product engineer in the door concept phases. Also to help on decisions related to the door Design concept early in the development, minimizing the impacts from possible required changes in later project phases. From a simplified model this plan was made and the output of it was compared to simulations of complex models (CAE). The proposed model has acceptable error, when compared to CAE models, showing the simplifications made were made using criteria in order to impact the less possible in the door closing effort value."
A Case Study: Application of Analytical and Numerical Techniques to Squeak and Rattle Analysis of a Door Assembly,"Squeak and rattle (S&R) problems in body structure and trim parts have become serious issues for automakers because of their influence on the initial quality perception of consumers. In this study, various CAE and experimental methods developed by Hyundai Motors for squeak and rattle analysis of door systems are reported. Friction-induced vibration and noise generation mechanisms of a door system are studied by an intelligent combination of experimental and numerical methods. It is shown that the effect of degradation of plastics used in door trims can be estimated by a numerical model using the properties obtained experimentally. Effects of changes in material properties such as Young's modulus and loss factor due to the material degradation as well as statistical variations are predicted for several door system configurations. As a new concept, the rattle and squeak index is proposed, which can be used to guide the design. The predicted S&R of the door system from the CAE process were compared with experimental results. Practical applications of the developed process and possible future directions of CAE based S&R analysis are discussed."
A CAE Study on Side Doors Inner Panel Deflection under Glass Stall Up Forces,"Not only well-functioning, but also the way operating everyday items ""feel"", gauges costumer perception of an automobile robustness. To prevent costumer dissatisfaction with door trim panel movement when operating power windows, deflections must be kept small. Deflections of inner panel are seen through trim panel and are responsible for giving a flimsy idea of the door. In this paper, inner panel movement for a fully stamped door in full glass stall up position is analyzed. Through CAE analyses, inner panel behavior was compared, considering different types of reinforcement for belt region."
Comparative Dynamic Analysis of Sliding Door Based on LS-Dyna and ADAMS,"Nowadays, the design and development of the sliding door has been gained great attention for its easy egress and ingress. However, most studies on the kinematic and dynamic characteristics of sliding doors were based on the commercial code ADAMS, while the accuracy of flexibility in modal synthesis method and the ability of complex contact condition may not be guaranteed. Thus, a new dynamic analysis method by using the commercial code LS-Dyna was proposed in this paper to take into account the complex deformation and boundary conditions based on the finite element model. The impact force obtained from the Ls-dyna was compared with that from ADAMS when their monitoring points speed and closing time maintained the same during the sliding process. The impact force between the rollers and the guides was employed as evaluation criterion for different methods because of its effect on the roller wear and the moving smoothness in the sliding process. To validate the results, the impact force was measured by using the strain gauges and optical fibers measure. It turned out that the impact force from LS-Dyna agrees better with the experimental test than that from ADAMS. LS-dyna outperforms ADAMS, in terms of modeling method, dynamic analysis theory and boundary condition. In addition, the dynamic analysis based on finite element method in LS-Dyna environment can simulate the structural deformation and the motion space coupling boundary condition during the sliding process of door better."
Re-design of Power Sliding Door Pulley System,"The power sliding door system(PSD) is being equipped in the MPV(Multi-Purpose Vehicle/minivans) vehicle for convenience in the door operation. This study will focus on package space optimization for interior design and overall vehicle packaging for the vehicles equipped with PSD. To optimize the package, investigation for PSD's structure need to be done and the examples of other vehicle maker will be investigated and compared. The study that considers performance and package requirements resulted in a unique PSD design. And finally, this study will show the result vehicle in which the optimized mechanism is applied."
Rivet and Bolt Injector with Bomb Bay Ejection Doors,"Electroimpact's newest riveting machine features a track-style injector with Bomb Bay Ejection Doors. The Bomb Bay Ejection Doors are a robust way to eject fasteners from track style injector. Track style injectors are commonly used by Electroimpact and others in the industry. Using the Bomb Bay Doors for fastener ejection consists of opening the tracks allowing very solid clearing of an injector when ejecting a fastener translating to a more reliable fastener delivery system. Examples of when fastener ejection is needed are when a fastener is sent backwards, when there are two in the tube, or when a machine operator stops or resets the machine during a fastening cycle. This method allows fasteners to be cleared in nearly every situation when ejecting a fastener is required. Additional feature of Electroimpact's new injection system is integrated anvil tool change. Anvils with fingers are parked on each Injector and an indexing system automatically changes tools for different fastener diameter. Fundamentally, this track-style Injector has only one moving part, the Pusher, used in every fastening cycle. With the Bomb Bay Door ejection system and the integrated automatic tool change, this injection system is very flexible, and is likely one of the fastest in the industry with injection times of under a second. In addition to speed, the new eject system is a robust way to recover from common errors, adding to machine reliability. Overall the new injection system featured on Electroimpact's new riveting machines is a fast, flexible, and robust new system for fastener delivery."
Challenges Associated with a Complex Compound Curvature Passenger Doors,"This study investigates challenges associated with integrating a passenger (PAX) door on complex compound curvature (CCC) fuselages. Aerospace companies are investigating concepts that no-longer have constant cross-section (CS) fuselages. The PAX door is based on a generic semi-plug door for a long range business jet (BJ). This study investigates limitations of locating the door by varying the transition zone angle. A parametric CATIA tool, coupled with the use of finite element model (FEM) results can highlight key drivers in the design and location of PAX doors, creating a first-draft structural layout. The associated impact on the design and structural architecture for a fold down PAX door with integrated stairs is discussed. The impact of CCCs on the PAX door design is investigated with consideration to location, kinematics and function of the door. Design requirements, when coupled with stress analysis to simulate pressurization effect of the load applied to the stops, can create a powerful tool. Combining the architectural layout, design requirements and top-level stress analysis can be used to define limit curves and understand key design drivers that impact the door position, with reference to weight, design and human factor constraints. The design conclusions to-date suggest for a transition angle above 5 degrees, the structure is too complex to use a traditional frame and lintel design and will be an interesting case for bird impact. Below 5 degrees is the limit for conventional door and kinematic designs in-line with frames."
InCar - Advanced Door Design,"The ThyssenKrupp InCar Project is a comprehensive R&D development that gives automotive manufacturers modular solution kits for body, chassis and powertrain applications. The solution kits developed within this project offer weight reduction, cost savings or improved functionality. This paper will focus on the two front door solutions developed within the InCar project. The first door solution, called the Lightweight Door, achieved a 13% weight reduction. This door features a 4-piece tailored blank inner panel and a sandwich material outer panel. The second door solution, called the Advanced Door, is a completely new and innovative door architecture that uses a 2-piece tailored blank mid panel and ultra thin Dual Phase 500 outer panel to achieve an 11% weight reduction. Prototypes were manufactured and tested for both door solutions. This paper will provide a detailed description of everything related to the development of these door solutions, including manufacturing and assembly processes, performance, materials, and cost estimation."
Study of the Sliding Door Shaking Problem and Optimization Based on the Application of Euler’s Spiral,"This study focuses on the sudden shaking phenomenon of a sliding door passing through a corner. This phenomenon requires attention because shaking during movement can lead to a harsh operation feeling and a short service life. An experiment based on a test setup was conducted, and the sudden change in the acceleration of a sliding door panel was measured. Based on multi-body dynamics (MBD) analysis and a rigid-flexible coupled model of the sliding door system, the cause of the sudden shaking was determined to be the discontinuous curvature of the middle rail trajectory. A transition curve was proposed as the solution for the discontinuous curvature, and Euler’s spiral was applied in the redesign of the middle rail trajectory. Verified by simulations, the results exhibit considerable improvement in sliding door movement stability, with large reductions in the maximum center of mass (CM) acceleration and guide roller impact force."
Application Study of Blind Spot Monitoring System Realized by Monocular Camera with CNN Depth Cues Extraction Approach,"The image from monocular camera is processed to detect depth information of the obstacles viewed by the rearview cameras of vehicle door side. The depth information recognized from a single, two-dimensional image data can be used for the purpose of blind spot area detection. Blind spot detection is contributing to enhance the vehicle safety in scenarios such as lane-change and overtaking driving. In this article the depth cue information is inferred from the feature comparison between two image blocks selected within a single image. Convolutional neural network model trained by deep learning process with good enough accuracy is applied to distinguish if an obstacle is far or near for a specified threshold in the vehicle blind spot area. The application study results are demonstrated by the offline calculations with real traffic image data."
Utilizing Weathering Effect to Understand Squeak Risk on Material Ageing,"Squeak and rattle concerns accounts for approximately 10% of overall vehicle Things Gone Wrong (TGW) and are major quality concern for automotive OEM’s. Objectionable door noises such as squeak and rattle are among the top 10 IQS concerns under any OEM nameplate. Customers perceive Squeak and rattle noises inside a cabin as a major negative indicator of vehicle build quality and durability. Door squeak and rattle issues not only affects customer satisfaction index, but also increase warranty cost to OEM significantly. Especially, issues related to door, irritate customers due to material incompatibilities. Squeaks are friction-induced noises generated by stick-slip phenomenon between interfacing surfaces. Several factors, such as material property, friction coefficient, relative velocity, temperature, and humidity, are involved in squeak noise causes. For example, door armrest leather is exposed longer to sunlight and when customer places his hand on the armrest, an annoying squeak noise is generated due to permanent or temporary weathering effect. In this study, an experimental work is conducted to investigate squeak performance of door trim materials against weather ageing effect. As per the standard SAE-J2412, one thousand five hundred hours of polymer weathering test which is considered equivalent to 5 years of product life were performed to door trim material samples. Material compatibility test were performed on door trim samples at different time intervals of 0, 250, 500,750, 1000& 1500 hrs to evaluate its squeak risk behavior. On basis of RPN results, it was found that some material combination failed at 500 and 750 hrs highlighting squeak risk due to weathering effect. This paper introduces a new DVP, where a process can be established for material selection and avoid customer irritants and improve the perceived quality not only for a new vehicle but even after mileage degradation."
Door Seal Behavior Prediction and Enhancement in Performance Using Digital Simulation,"Automotive door seal has an important function which is used extensively where interior of the vehicle is sealed from the environment. Problem with door seal system design will cause water leakage, wind noise, hard opening or closing of doors, gap and flushness issue which impair customer’s satisfaction of the vehicle. Moreover, improper design of seal can lead to difficulty in installation of door seal on body panel. The design prudence and manufacturing process are important aspect for the functionality and performance of sealing system. However, the door sealing system involves many design and manufacturing variables. At the early design stage, it is difficult to quantify the effect of each of the multiple design variables. As there are no physical prototypes during rubber profile beading-out stages, engineers need to carry out non-linear numerical simulations that involve complex phenomena as well as static and dynamic loads for door seal. This paper presents a digital simulation design tool based on FEM, basic governing laws and incompressibility constraints. Door seal was analyzed for compression load deflection (CLD) behavior using nonlinear finite element analysis in MSC Marc Mentat™. The analysis results provided some major parameters, such as seal deformation, contact pressure and contact length of seal, which would influence the functionality and performance of the door sealing system. The analysis results have been compared with available test data, and very good correlation was obtained. This analysis also evaluated the influence of manufacturing deviations. This analysis method developed into a tool that is capable of predicting water leakage, wind noise and hard to open/close problems caused by either product design or manufacturing process."
Sink Butt Welding for 120 Degree Door Frame Design,"This paper deals with vehicle door 120-degree joint rust issue and water leak faced in most of SUV cars. Generally based on vehicle segment its styling curves and exterior design are defined. A Sedan or Hatchback is provided with curves to show its fluidic design but a SUV is provided with Straight lines to show its aggressive look. In existing condition door frame Joint has sharp joints where weld bead is added to prevent rust in joint area, but still improper seating of weather strip on weld bead cause water leak. Door’s A Pillar Frame and Horizontal Frame match at 120 degree joint edges are chamfered straight to match perfectly. Weld bead runs over the matching profile to join it. But weld bead project over the Frame surface and affects weather strip seating & results in poor sealing. Adhesive added for better sealing also follows the same path on bead and create a path way for water entry. Thus in long run this water stagnates and cause chronic rust issues in frame. This in turn results in high claim cost within warranty period. It is serious issue which should be addressed. This paper investigates deeply the process of eradicating the rust issue and water leak issue simultaneously. Edges of frame are provided with forming at 120 Joint matching areas. So that weld bead gets sink into shallow depth without projecting out from the surface. This flattened profile of weld bead on frame surface results in perfect sealing of weather strip. This is how sink weld prevents rust and arrest water entry."
Squeak Noise Prediction of a Door Trim Panel Using Harmonic Balance Method,"Squeak and rattle noise in a vehicle’s interior is perceived as an annoying sound by customers. Since persistent noise (e.g. engine, wind or drive train noise) has been reduced continuously during the last decades, the elimination of sounds, which have their origin in the vehicle’s interior components, is getting more important. Therefore, noise prediction based on simulation models is useful, since design changes can be realized at lower costs in early virtual development phases. For this task, linear simulation methods are state of the art for the identification of noise risk, but in general without knowing if a sound is audible or not. First approaches have been developed based on the Harmonic Balance Method to predict squeak noise and assess their audibility. This paper presents vibroacoustic measurements at a door trim panel for squeaking and non-squeaking configurations. Vibrations are excited harmonically by a force controlled low noise shaker. The system response is measured in a semi-anechoic chamber by acceleration sensors and audibility is assessed. Additionally, a 3D finite element model is built and the Harmonic Balance Method using a dry friction law is applied to predict the acoustic behavior. Finally, the simulation results are compared to the measurements. A good agreement between simulation and experiment can be observed."
Development of a Thin-Wall Magnesium Automotive Door Inner Panel,"Cast magnesium (Mg) door inner panels can provide a good combination of weight, functional, manufacturing, and economical requirements. However, several challenges exist including casting technology for thin-wall part design, multi-material incompatibility, and relatively low strength versus steel. A project was supported by the US Department of Energy to design and develop a lightweight frame-under-glass door having a thin-wall, full die-cast, Mg inner panel. This development project is the first of its kind within North America. The 2.0 mm Mg design, through casting process enablers, has satisfactorily met all stiffness and side-impact requirements, with significant mass reduction and part consolidation. In addition, a corrosion mitigation strategy has been established using industry-accepted galvanic isolation methods and coating technologies. The performance of the Mg design has been demonstrated through component and vehicle tests. This article is an updated publication of a previously published International Mg Association (IMA) proceedings paper [1] (with agreement from the Association)."
Damping out booming noise,"NVH improvement techniques are gaining traction with the goal to improve the quality perception of off-highway equipment performance and operator comfort. As NVH gains importance in the quality of off-highway machine performance and operator comfort, it is essential to understand every aspect of the machine noise and its annoyance effect on the operator, then reduce the noise to a level that does not affect comfort and performance. Booming noise-a low-frequency NVH phenomenon below 200 Hz often described as a continuous bass drum roll, distant thunder sound, or a deep resonant sound like an explosion-is a major concern in off-highway machines. The booming noise in off-highway machines can be caused by a combination of factors: the low natural frequencies and damping of the large panels of machine cabs; the low acoustic modes of the cab cavity; low-frequency excitation into the cab from machine noise sources such as engine, exhaust, cooling fan, etc.; and low frequency excitation to the machines from machine work tools and ground interaction inputs (tire lug, road profile, etc.)."
Recent Advances in Powertrain Sound Quality Hardware Tuning Devices and Perspectives on Future Advances,"Over the past decade there have been significant advances made in the technology used to engineer Powertrain Sound Quality into automobiles. These have included exhaust system technologies incorporating active and semi-active valves, intake system technologies involving passive and direct feedback devices, and technologies aimed at tuning the structure-borne content of vehicle interior sound. All of these technologies have been deployed to complement the traditional control of NVH issues through the enhancement of Powertrain Sound Quality. The aim of this paper is to provide an historical review of the recent industry-wide advances made in these technologies and to provide the author's perspective on what issues have been addressed and what opportunities have been delivered. The paper will offer the author's perspective on how these existing Sound Quality hardware tuning technologies have evolved, how they will continue to evolve, what new technologies are showing potential, and how they will have an increasingly significant contribution to make in the medium and long term future of Vehicle NVH and Sound Quality development."
Applications of the Statistical Energy Analysis to Vibro-Acoustic Modeling of Vehicles,"In recent years, SEA has been recognized as an important tool to model the vibro-acoustic behavior of vehicles in mid and high frequencies. Through SEA it is possible to develop vehicle models early in the design stage, reducing the risk of future noise problems and allowing the optimization of noise control treatments. Moreover, at the final design stages, a SEA model can be use to evaluate changes at the project, reducing costs with experiments. In a SEA model, the structure under study is divided in subsystems. The capacity of each subsystem of storekeeping, dissipating and transmitting energy is described by three parameters: modal density, loss factor and coupling loss factor. The noise and vibration sources are include in the model as power inputs to subsystem and, based on an equilibrium power balance, it is possible to calculate the energy of each subsystem. The results obtained by SEA models should be interpreted as average values in time, in the frequency band, in space and at an ensemble of random structures. In this work, the applications of SEA at the vibro-acoustic modeling of vehicles are discussed. The details that should be observed when defining the structural and acoustic subsystem are pointed out. The main methods for the determinations of the SEA parameters are introduced. Special emphasis is given to the calculation of the power inputs of the main noise and vibration sources in a vehicle. Finally, some practical applications of SEA at the automotive industry are presented and discussed."
TREASURI: An Innovative Simulation Method for the Vibro-Acoustic Design of Passenger Compartments,"0 The accuracy of nowadays CAE tools for simulation of sound pressure level distributions in the passenger compartment of vehicles is not satisfactory because of the simplify models, especially with regard to the description of common passive acoustical treatments. This report describes the application of the TREASURI method on a complete vehicle, equipped with sound deadening treatment sound absorbing material sound insulation treatment and interior trim material (e.g. instrument panel, seats, center console). In order to validate the method, the simulation results were compared with the measurement results from the corresponding vehicle. The evaluation shows that the TREASURI approach yields considerable improvements in simulation accuracy up to 300 Hz compared to classical approaches [1]. This method now enables reliable predictions of acoustical influence on structural modifications and changes of the sound package."
Visualization of Sound Field in Automobile Cabin using Sound Intensity Technique,"For examining sound field in automobile cabin, it is important to visualize a noise source and it's behavior. This paper reports the results of visualized sound field using measurement data of sound intensity analysis. In general, it is difficult to obtain an appropriate result for source localization in reflective sound field where normal mode can be occurred with sound intensity analysis. We tried to distribute many receiving points and examined noise source localization in automobile cabin with this technique and found it effective. After the treatment of sound insulation, we found that measurement results reveals difference with and without countermeasure."
Real-Time Pass-by Noise Source Identification Using A Beam-Forming Approach,"Noise source identification is becoming a key issue in the dimensioning and troubleshooting steps of the design process. In the automotive industry, OEM's and suppliers need to assess the entire description of vehicle noise emission, both for interior comfort and exterior radiation concerns. The resolution of pass-by noise issues pose one of the most significant problems to vehicle designers. While many commercially available systems allow the evaluation of the overall noise emission at any speed and position during the test the task of identifying specific sources is still mainly performed using component masking. A new measurement technique has been developed using a microphone array (typically 2m × 2m with 64 transducers or more) and acoustic beamforming techniques that allows visual source identification at any point during the test. Typically, the entire side of a vehicle can be evaluated with one single measurement run. This paper describes the method employed and presents results obtained from a high-speed pass-by test on a minivan."
Development of a Hybrid SEA Modeling Scheme for a Passenger Car,"A hybrid SEA modeling scheme has been developed and applied to obtain an accurate SEA model for a passenger car. In this study, the detailed workflow associated with the hybrid SEA modeling scheme will be described. Each step in the workflow will be discussed in terms of the obtained data, the corresponding analysis and results. In those steps, several innovative methods for developing the hybrid SEA model will be presented. Finally, a road noise analysis will be performed using the hybrid SEA model to validate the SEA model for the passenger car. In order to demonstrate the accuracy of the model, the analysis results such as the sound pressure level of car interior will be compared with the measurements."
Development of a Parametric Blend Door Computer-Aided Design System,"This paper describes the development of an analytical tool for the design automation of the temperature blend door mechanism in an automotive HVAC system. The function of the blend door is to control the temperature of the air blown into the cabin interior by regulating the mix of air passing through the heater core. The objective in the design process is to achieve a prescribed function of temperature with respect to control position at the instrument panel. The control effort to effect the desired temperature change is also another important consideration for customer satisfaction. The current design process is empirical in nature and relies on laboratory and vehicle testing with prototypes. The process is also iterative in nature and may continue until the end of the overall design cycle of the complete air handling subsystem. A parametric feature-based computer model, described subsequently in detail, allows for virtual prototyping of the blend door control mechanism. With this model, various blend door designs can be explored early in the design cycle. Late changes required for packaging can also quickly be analyzed. Kinematic analysis of the blend door mechanism allows the control curve and control effort to be predictive. This desktop simulation tool will enable designs to be optimized or permit the number of options to be narrowed, which will reduce test time and shorten design cycle time. Illustration of the desktop tool is based upon predicting control curves and efforts for a production HVAC system. Also, airflow and temperature data from CFD analysis for this production system is presented. Finally, predicted results are compared and correlated with actual laboratory and vehicle test data."
Development of a Film Door Type Air Conditioning Unit,"Recently, an increasing demand for comfort has been accelerating the trend toward multifunctional car air conditioners, including zone air conditioning which controls the cabin temperature independently for the driver and the passenger and compensates for the side solar radiation. In addition, the multifunctional air conditioner should be compact to save cabin space and ensure passenger comfort. This report describes the development of a compact and multifunctional car air conditioning unit."
Design and Development of Automatically Deployed Entry Steps for a Fire Truck Cab,An automatically deployed fold-down step has been developed for use on fire apparatus cabs. The step operates pneumatically as the cab doors are opened. This feature optimizes the ergonomics of cab entry while maximizing the interior space available for occupants and equipment.
Measures to Quantify the Sharpness of Vehicle Closure Sounds,"Impulsive sound events (i.e. door closing) are often characterized as being undesirably sharp sounding. A high degree of perceived sharpness is normally related to large amounts of high frequency energy relative to the low frequency energy. In this project third octave data generated from a filterbank was used to calculate the center of gravity (cg) of the third octave bands. The result is the frequency corresponding to the centroid of the third octave data. Sounds with substantial high frequency energy have a centroid location that occurs at a higher frequency. The mean of the third octave cg over the duration of the transient event was investigated, in addition to sharpness as defined by Aures [1] and calculated on a commercially available analyzer. Correlation analyses to subjective data indicate that the mean third octave cg and the commercially available method produce comparable results for the vehicle closure sounds studied here. Sounds with more high frequency energy during the Initial impact were sharper, while sounds with substantial low frequency energy following the impact were less sharp."
Extended Cab Side Access Panels - Compact Pick-Up Trucks,"In the past, all known, compact pickup truck structures have been limited to the use of two doors to allow for access to the interior regions of the cab. This paper will address the issue of locating a side access panel to an existing vehicle structure, the development criteria used for the panel hinges, the integration of the safety belt system and the advantages of the interior trim attachment methods. Examination will include a review of specific design considerations used to meet governmental and consumer requirements."
"POGO™ Flexible Tooling Universal Holding Fixture for Cutting, Drilling and Assembly in the Aerospace Industry","The aerospace industry has entered a new level of World Class Manufacturing, in which manufacturing functions require fixturing to be just as flexible as the machine tool doing the operation. Flexible tooling has opened new doors for the aerospace industry by creating new tools which are automatically reconfigurable and totally reusable on future programs. Benefits include decreases in non-recurring costs, (such as in the area of tool design and fabrication) and recurring costs, (such as in the area of tool setup / removal and storage)."
Improving Recyclability Through Planned Product Revisions,"Whether propelled by a concern for the environment, increasingly stiff legislation, or higher disposal costs, companies are trying to reduce the environmental impacts of their products. At the same time, designers are forced to balance the need to get a product out the door with the desire to improve the product's functionality. Candidate designs are often so constrained that addressing environmental goals proves impossible. In this paper, we discuss the improvement of recyclability for vehicle assemblies through a process of planned design changes over multiple revisions of the product. Specifically, we present the results of a case study describing the creation of a strategy for focusing the recyclability improvement effort to a generic instrument panel (I/P). The possible improvement in recyclability is examined as well as the impact on other design characteristics as the limiting factors for the instrument panel are chosen. Based on this analysis, a plan for focusing the design effort to improve vehicle recyclability is provided."
Application of a Laser Vibrometer for Automotive Aeroacoustic Analysis,"The Scanning Laser Vibrometer can make full field, high resolution measurements of the normal surface velocity of automotive door glass and sheet metal vibrations. These properties make the vibrometer a very useful tool for locating compliant and noisy areas on the surface of a vehicle, generated by exterior wind noise. An advantage of the vibrometer is that it measures the vibration of the surface, capturing the transfer of noise through the surface, rather than simply measuring the exterior wind noise. Methods of experimental setup, testing, and problem analysis on outside rear view mirror/A-pillar/Sideglass configurations and body panel vibrations are discussed in the paper."
Optimizing Parts and Systems Integration with Engineering Thermoplastics to Meet the Challenges of Future Automotive Door Systems,"As automakers struggle to meet often conflicting safety, weight, styling, and performance requirements, engineering thermoplastics (ETPs) are making increasing inroads into applications that once were the exclusive domain of metals, glass, and thermosets. A good example of this is in the door systems area, where the performance, design flexibility, aesthetics, parts integration, and lower specific gravity offered by ETPs are allowing highly integrated and efficient modules to be created that, in turn, increase assembly efficiency and reduce mass, part count, warranty issues, and systems costs. This paper will use several case studies on innovative door hardware modules and door panels to illustrate the advantages offered by this versatile class of engineering materials."
Development of a Sled-to-Sled Subsystem Side Impact Test Methodology,"A sled-to-sled subsystem side impact test methodology has been developed by using two sleds at the WSU Bioengineering Center in order to simulate a car-to-car side impact, particularly in regards to the door velocity profile. Initially this study concentrated on tailoring door pulse to match the inner door velocity profile from FMVSS 214 full-scale dynamic side impact tests. This test device simulates a pulse quite similar to a typical door velocity of a full size car in a dynamic side impact test. Using the newly developed side impact test device three runs with a SID dummy were performed to study the effects of door padding and spacing in a real side impact situation. This paper describes the test methodology to simulate door intrusion velocity profiles in side impact and discusses SID dummy test results for different padding conditions."
Experimental Assessment of Wind Noise Contributors to Interior Noise,"Wind noise reaches the interior of a vehicle through a variety of mechanisms including: aerodynamic excitation of vibration and reradiation from the greenhouse surfaces; acoustic transmission through door seals including gaps and glass edge leaks, and due to airborne transmission of noise generated by wind interaction with body panels. This paper presents experimental results that quantify contributions to interior noise from individual greenhouse surfaces and from airborne sources on the underbody. The measurements were carried out on a production vehicle in a wind tunnel. Greenhouse surfaces, in addition to the driver window are important contributors to interior noise along with airborne transmission of noise generated due to the flow over and through the vehicle underbody."
Sound Transmission Through Primary Bulb Rubber Sealing Systems,"Structural sound transmission through primary bulb (PB) sealing systems was investigated. A two-degrees-of-freedom analytical model was developed to predict the sound transmission characteristics of a PB seal assembly. Detailed sound transmission measurements were made for two different random excitations: acoustic and aerodynamic. A reverberation room method was first used, whereby a seal sample installed within a test fixture was excited by a diffuse sound field. A quiet flow facility was then used to create aerodynamic pressure fluctuations which acted as the excitation. The space-averaged input pressure within the pseudo door gap cavity and the sound pressure transmitted on the quiescent side of the seal were obtained in each case for different cavity dimensions, seal compression, and seal designs. The sound transmission predictions obtained from the lumped element model were found to be in reasonable agreement with measured values. The measured noise reduction was found to be very similar for both types of excitation. This confirmed that an acoustic excitation may be used instead of aerodynamic pressure fluctuations for sound transmission measurements, and that the barrier performance of the PB seal was not significantly affected by the presence of a static pressure gradient associated with the mean flow. The wind tunnel method was also found to yield a better signal-to-noise ratio than the reverberation room method."
Static and Dynamic Dent Resistance Performance of Automotive Steel Body Panels,"In recent years, strict weight reduction targets have pushed auto manufacturers to use lighter gauge sheet steels in all areas of the vehicle including exterior body panels. As sheet metal thicknesses are reduced, dentability of body panels becomes of increasing concern. Thus, the goal becomes one of reducing sheet metal thickness while maintaining acceptable dent resistance. Most prior work in this area has focused on quasi-static loading conditions. In this study, both quasi-static and dynamic dent tests are evaluated. Fully assembled doors made from mild, medium strength bake hardenable and non-bake hardenable steels are examined. The quasi-static dent test is run at a test speed of 0.1 m/minute while the dynamic dent test is run at a test speed of 26.8 m/minute. Dynamic dent testing is of interest because it more closely approximates real life denting conditions such as in-plant handling and transit damage, and parking lot damage from car door and shopping cart impact. The dent resistance performance of the three steel types are examined and compared for both static and dynamic test conditions."
"DEVELOPMENT OF A UNIQUE, GAS-INJECTION MOLDED DOOR HARDWARE MODULE FRAME","A unique design, engineering, and manufacturing approach has been used to create the first all-plastic door hardware module frame. The result of many years of intensive development efforts by a team of companies, the gas-assist injection molded frame features a high degree of parts consolidation and has been critically acclaimed as “the first major metal-replacement automotive part since the bumper, a quantum leap in injection molding complexity, and the biggest commercial breakthrough ever in gas assist molding [1].” The program also proved to be an excellent example of the types of technological breakthroughs that can come from concurrent engineering and strategic partnering. This paper will provide an overview of the component's development, describe the many challenges facing the team, and share solutions that contributed to the success of the program. It will also illustrate the benefits of successfully implementing a design and production strategy that carefully matches design, materials, tooling, and processing."
Automotive Body Component Field Corrosion Behavior in the De-Icing Salt Zone,"Doors were removed from recycle-yard vehicles in Syracuse, N. Y. and examined in the laboratory as part of an on-going field study on corrosion behavior trends in the de-icing salt region of the U. S. Lower doors, including hem-flange internal surfaces, were examined, and performance trends as a function of materials selection, age and mileage were determined. The results to date on doors from 167 Syracuse vehicles are indicative of the nature and history of salt-induced corrosion in the region, and they indicate the degree of benefit from galvanized construction and body design features."
Material Options for Automotive Interior Trim,"This paper outlines the relationship between airbag door choices and instrument panel coverstock materials which are being used in the global automotive market for passenger vehicles as well as those materials that are being considered for use in future vehicles. The introduction of an invisible airbag door into the instrument panel is changing the material and testing requirements as safety and reliability are now key considerations. Increasing material options are available to meet these requirements. In this paper, we review the material options, processing methods available, advantages/disadvantages of each, and the current market status of the different materials."
Design and Development of a Magnesium/Aluminum Door Frame,"This paper describes the methodology by which a combination die cast magnesium and extruded aluminum door frame was developed using a current production steel door design as the base model for comparison. Product performance data, such as side impact requirements and overall door stiffness, along with the packaging of existing internal hardware, is presented. The results are verified by computer modeling. A prototype casting was produced to validate and compare castability requirements and geometry constraints of the door frame. An economic study is included that investigates the potential of developing such a system suitable for production. The results suggest that economic benefits may be obtained by using such a lightweight door system compared to an existing steel door design."
Measurement of Airborne Noise Reduction of Production Door Components on a Buck,"Various automobile door components were evaluated for air-borne noise reduction using production and prototype door assemblies which were modified to fit an SAE J-1400 test fixture. The in-door laboratory evaluation provided a single noise reduction rating in decibels for diverse door assembly components, with different noise reduction mechanisms. This test method overcame some of the shortcomings associated with evaluating each component individually in accordance with an acoustical material test standard."
Nd:YAG Laser Welding for Automotive Manufacturing Applications,"The power output of commercially available continuous wave (CW) Nd:YAG lasers has increased substantially over the last few years. Models which can deliver 4 kW to the workpiece are now available. At this power level, the Nd:YAG laser can effectively compete with the CO2 laser in many laser welding applications. The easier, fibre optic based, beam delivery of the high power Nd:YAG laser makes a number of applications possible which were considered impractical using CO2 laser technology. This paper will first describe the general characteristics of an Nd:YAG laser system as configured for welding, and contrast these features with a typical CO2 laser welding system. Points of discussion include: laser power, beam delivery options, focus spot characteristics including the capabilities of twin spot beam delivery with an Nd:YAG laser, and the interaction of the laser beam with the metal surface, including a brief description of the laser generated plasma. Some specific configurations for an Nd:YAG laser-based weld cell will then be described. In the second section, a number of applications for Nd:YAG laser welding will be described, and sample parts and weld characteristics will be shown. These applications include: welding of tailored blanks for body stampings using 1D and 2D weld geometries, welding of reinforcing patches onto blanks for shock towers, laser welding of hemmed door and hood joints, laser welding of tailored tubes for hydroforming, laser welding of aluminum panels, and laser welding for auto body assembly. The Nd:YAG laser is not expected to replace the CO2 laser completely, but there are a number of applications which are better suited to laser welding with an Nd:YAG than a CO2 laser. The ability to deliver the laser power to the workpiece through a flexible fibre also opens new laser welding applications, and creates more competition for traditional joining techniques."
Intelligent Audio Amplifier,"An intelligent amplifier has been developed which delivers output power to either a two or four speaker audio system. The amplifier determines the number of speakers present during the start-up sequence and configures itself either as two BTL amplifiers or four single ended amplifiers. The system does not require any wiring modifications to operate in either mode and will reconfigure itself on each start-up cycle allowing system modifications, such as adding speakers, without additional wiring or hardware modifications. Difficulties arise when determining the presence of speakers in an automotive environment. Extraneous noise sources such as door slams, hatch slams and engine cranking can cause erroneous measurements thus inappropriate configurations. The presented circuit was determined to be immune to these noise sources and is based upon: 1. Integration of measurements over a fixed period of time 2. Applying a large voltage to overcome noise sources without creating audible disturbances 3. Fixed switch on behavior"
Concept to Production: Continuous Surface Keypad Switch,"The objective of this paper is to impart the challenges presented and the solutions derived to transform an artist's rendering into a production driver's door switch to be used in the interior of a high profile sports car. The challenges took many forms throughout the process, from data translation and packaging, to the final decorative issues. The results are a finished product providing a new approach to automotive interior switch design. It incorporates a low profile, continuous plane keypad with “soft touch” feel, tactile feedback, and integrated back lighting."
Optimized Radii for Draw Dies,"This paper deals with the radii of draw dies for sheet metal parts, like fenders, hoods, and doors. For relative flat parts, like hoods, it is important to get at least a 2% forming rate in the middle of the part to reach minimum of stiffness, work hardening, and sufficient geometric accuracy. This can be influenced by the punch radii. Therefore, optimal punch radii should be known. First experimental results about optimal punch radii where published by J.L. Duncan and B.S. Shabel in the SAE-Paper No. 780391. At the Institute for Metal Forming Technology of the University of Stuttgart, Germany, a “Modified Duncan Shabel Test” (MDS-Test) has been developed. This test makes it possible to investigate not only the punch radii but also the die radii. This paper shows optimal punch and die radii as a function of sheet metal, sheet thickness, as well as of the die material."
High Mileage Squeak and Rattle Robustness Assessment for Super Duty Cab Weight Reduction Using High Strength Steel and Adhesive Bonding,"Squeak and rattle is one of the major concerns in vehicle design for customer satisfaction. Traditionally, squeak and rattle problems are found and fixed at a very late design stage due to lack of up-front CAE prevention and prediction tools. An earlier research work conducted at Ford reveals a correlation between the vehicle overall squeak and rattle performance and the diagonal distortions of body closure openings under a static torsional load. This finding makes it possible to assess squeak and rattle performance implications between different body designs using body-in-prime (B-I-P) and vehicle low frequency noise vibration and harshness (NVH) CAE models at a very early design stage. This paper presents an application of this squeak and rattle assessment method for a design feasibility study concerning a cab structure of a super duty truck for weight reduction using high strength steel and adhesive bonding. The study indicates that downgaging and substitution of mild steel with high strength steel combined with adhesive bonding in selected areas of a cab structure can achieve 12.7 Kg (4% of B-I-P) weight reduction without tooling changes while maintaining high mileage squeak and rattle performance of the baseline vehicle."
High Frequency Effects on Localization and Sound Perception in a Small Acoustic Space,"As compared to home audio, the automobile has a different spatial and spectral distribution of sound. This can cause stereo images to blur or shift due to conflicting localization cues. The impact of interaural time and level differences is discussed, along with frequency-selective pinna and head cues. Review of the literature shows that our poorest localization is for mid frequencies (∼2kHz). Yet in an automobile, low frequencies are severely relocated with a minimum effect on fidelity. It is suggested this is because middle frequencies dominate the perception and localization of sound. Therefore, some high frequency information might also be relocated."
Prediction of Flow-Induced Noise in Automotive HVAC Systems Using a Combined CFD/CA Approach,"Noise emission from automotive HVAC systems has become an important factor for passenger comfort. Consequently, efforts are made during the design phase to minimize noise generation, and to improve sound quality. Predictive tools for the aeroacoustic behavior of components, subsystems and whole systems early on in the design phase are therefore desirable. In this paper a combined Computational Fluid Dynamics (CFD) and Computational Acoustics (CA) approach for the prediction of sound generation and propagation is investigated. Three different experimental setups, ranging from a more academic example to examples relevant in the design process of climate control systems, have been devised to provide test data for the evaluation. Experimental and numerical results are presented and discussed."
Experimental Investigation of the Response of the Human Lower Limb to the Pedestrian Impact Loading Environment,Three limbs were taken from post mortem human subjects and impacted on the lateral aspect by a free-flying (30 km/h) impactor below the knee joint. Tri-axial MHDs and tri-axial accelerometers were used to determine the kinematics of the limb; strain gages were used to measure surface strain on the tibia and femur; and acoustic sensors were used to identify the onset and timing of injury. This data set was analyzed to compute the response of the knee joint to a bumper impact. Post-test necropsy results showed that the primary injury mechanism in each case was complete avulsion of the Medial Collateral Ligament (MCL) and the Anterior Cruciate Ligament (ACL).
Geometric Visibility of Mirror Mounted Turn Signals,"Turn signals mounted on exterior rearview mirrors are increasingly being used as original equipment on passenger cars and light trucks. The potential for mirror-mounted turn signals (MMTS) to improve the geometric visibility of turn signals is examined in this paper. A survey of U.S. and UN-ECE regulations showed that the turn signals of a vehicle that is minimally compliant with U.S. regulations are not visible to a driver of a nearby vehicle in an adjacent lane. Measurements of mirror location and window geometry were made on 74 passenger cars and light trucks, including 38 vehicles with fender-mounted turn signals (FMTS). These data were combined with data on driver eye locations from two previous studies to assess the relative visibility of MMTS and conventional signals. Simulations were conducted to examine the potential for signals to be obstructed when a driver looks laterally through the passenger-side window. With a vehicle population that is fifty percent light trucks, MMTS are visible 52 percent more often than FMTS in this scenario. Based on the lateral visibility analysis, the optimal height for geometric visibility of a signal in the adjacent-vehicle scenario is 124 cm above the ground, approximately the average height of a light truck mirror. A plan-view eccentricity analysis showed that an MMTS is much closer to the viewing driver’s forward-directed line of sight than rear-mounted turn signals when the viewing driver’s vehicle is in or near the blind zone between the signaling driver’s mirror and direct peripheral fields of view. MMTS can improve the geometric visibility of turn signals in the adjacent-vehicle scenario that is believed to precede many lane-change/merge crashes. Further research will be necessary to determine if improved geometric visibility is accompanied by improved detection of turn signals by viewing drivers, and whether improved detection of turn signals has important safety implications."
Dynamic Element Analysis,"A new formulation for dynamic analysis of the response of vibro-acoustic systems is developed. The method is based on a discrete element formulation similar in geometry to a finite element model. However, the Dynamic Element Analysis uses transcendental functions for the response interpolation functions. The phase of the functions converges at high frequencies to the Statistical Phase. At low frequencies the interpolation functions converge to the polynomials used in finite elements. Thus, the Dynamic Element Analysis covers a wide frequency range without requiring a refinement of the mesh, and it provides a deterministic response in the mid-frequency range before converging to a statistically correct response at high frequencies. Examples are shown of the response of structures and acoustic radiation."
Lessons Learned Through Working With General Motors,"In many companies and corporations, a number of very good ideas never reach fruition, even after a substantial investment in time and money. Can corporations afford to squander such assets…or is it a result many other forces and variables that inadvertently conspire to failure? The Vibration Advisor Expert System is one of these great ideas with a significant amount of time and money invested and a proven functionality that didn't make it. This paper will describe the project and offer for discussion and thought, some of the reasons for implementation failure. It was the right tool at the right time - but it did not benefit the Corporation."
Measurement of Sound Impulses Due to Airbag Deployment in a Standardized Enclosure,The consistent measurement of airbag deployment noise places special demands on the enclosure in which the measurements are performed. The acoustical characteristics of the enclosure must be stable over long periods. It must also be sufficiently robust to withstand the loads involved. The use of a standardized enclosure provides a uniform basis for comparable measurements in different laboratories. The reasons for selecting a specific small cabin as the standard enclosure are discussed in this paper. Some examples of tests performed in the small cabin with a wide range of airbag systems are presented. High-speed film recordings of the deployment of the airbags were made simultaneously with the acoustic measurements. The stability of the acoustic environment and of the enclosure were important factors in obtaining reliable and comparable results.
Road Noise Reduction Using a Source Decomposition and Noise Path Analysis,"It is considered that improper usage of rubber bushes and weak dynamic characteristics of chassis and body structures yield interior road noise problems. This paper describes systematic processes for road noise improvement along with measurement and analysis process. Firstly, the noise sources are identified by using a source decomposition method. Secondly, the main noise paths are identified by using a noise path analysis (NPA) method. Thirdly, the design modification of body panels is suggested for road noise reduction by using a panel contribution analysis. Finally the method is validated by applying to road noise improvement process for a new vehicle."
A Study on the Development Process of a Body with High Stiffness,"Design optimization of a vehicle is required to increase a product value for noise and vibration performances and for a fuel-efficient car. This paper describes the development process of a high stiffness and lightweight vehicle. A parameter study is carried out at the initial stage of design using the mother car, and a design guide with a good performance is achieved early prior to the development of the proto car. Influences of body stiffness based on the relative weight ratio of the floor and side structures are analyzed. Results show that bending and torsional stiffness has a significant effect on weight distribution ratio. Influences of the distribution of side joint stiffness are analyzed through numerical experiments. Results reveal that the stiffness difference between the upper and lower parts should be small to increase the stiffness of a body. In addition, the process of designing the body attachment stiffness is summarized to ensure the vibration isolation of the suspension mounting unit. In the case of the rear suspension mounting unit, the body attachment stiffness is found to increase in the left and right direction, when the package tray pass-through structure is used on the rear wheel housing and rear floor joint, to minimize rear seat noise. This paper is expected to shorten the development period by the present stiffness analysis process. And a body with high stiffness and lightweight is developed for the vibration and noise performance at the initial stage of design."
Statistical Energy Analysis of a Fuel Cell Vehicle,"In this paper the application of Statistical Energy Analysis (SEA) to the sound package design for a fuel cell powered sedan is presented. Fuel cell vehicles represent a different challenge to a vehicle with a conventional powertrain. With the replacement of the internal combustion engine (ICE), a principal source of airborne and structure-borne powertrain noise, the expectation is that the cabin noise levels would be significantly reduced as the main noise sources would be road and wind noise. A fuel cell powertrain, however, has a number of mechanical sources on the body structure that will radiate airborne noise and may transmit significant structure-borne noise to the vehicle interior. With this alternative power train, much of the conventional wisdom on vehicle sound package developed from experience with ICE's must be reconsidered. Utilizing an SEA model, the paper discusses the unique problems encountered in designing a noise control package for a fuel cell-based vehicle, the packaging design issues related to space, weight and design restrictions, and presents some initial correlation results. It is concluded that an SEA model can be used to provide design recommendations on the high frequency NVH performance of the vehicle structure."
Development of a New Standard for Measurement of Impulse Noise Associated With Automotive Inflatable Devices,"The SAE Recommended Practice for measuring impulse noise from airbags, SAE J247, “Instrumentation for Measuring Acoustic Impulses within Vehicles”, was first published in 1971 and last affirmed in 1987. Many advances have occurred in understanding and technology since that time. Work in the automotive industry to investigate the characteristics of noise from airbag deployments has shown that large components of low frequency noise can be present when an airbag deploys in a closed vehicle. Others have shown that this low frequency noise can have a protective effect on the ear. Likewise, work for many years at the US Army Research Lab has investigated the risk of hearing loss for a human subjected to an acoustic impulse. That research led to the creation and validation of a mathematical model of the human ear, called Auditory Hazard Assessment Algorithm - Human (AHAAH). In 1998, the SAE Impulse Noise Task Force (INTF) of the Inflatable Restraint Standards Committee performed a series of experiments to help understand the predictions of the AHAAH model. This work compared in-vehicle test results with those obtained from an acoustic reverberation chamber. These tests used a method published by a German Airbag Consortium called the AK-ZV Working Committee and documented in report AK-ZV01. Much of this work was summarized in SAE J2531, an Information Report developed by the SAE Impulse Noise Task Force, documenting the state-of-knowledge in 2003. Also in 2003, Banglmaier and Rouhana reported on the results of over 100 tests performed to help clarify test conditions for the assessment of noise-induced hearing loss (NIHL). Based on all of this information, a new revision of SAE J247 has been drafted and is in the process of committee editing. This paper describes the changes made to SAE J247 and the rationale for those changes."
Application of Statistical Noise Generation and Radiation for Aeroacoustic Predictions in the Automotive Industry,"Flow-induced noise is an important issue in the automotive industry. TNO in cooperation with AVL developed an efficient hybrid Computational AeroAcoustics (CAA) method, aimed at actual engineering applications, i.e. fast, robust, accurate and able to handle highly complex geometries. The hybrid method is based on standard Reynolds Averaged Navier-Stokes solution of the flow field under consideration, and combines an Statistical Noise Generation and Radiation (SNGR) technique to generate a time-accurate realization of the turbulence and a high order, quadrature-free discontinuous Galerkin - Linearized Euler Equation (LEE) solver to predict the propagation of the acoustic waves. Owing to the unstructured grid strategy the present approach is both particularly well suited for the complex geometries common to car design as well as sufficiently flexible in selecting acoustically interesting subdomains. This paper demonstrates the capabilities of the CAA method in two cases on the noise induced by the flow around a car, and more specifically, by the A-pillar and rear-view mirror on the side window."
Xtreme Make-Over In 24 Hours,"Our conference chairman told me that this special technical section was structured to provide “some words of wisdom from the old guys” or something to that effect. I know I can meet most of his requirements. I am a pensioner and an oak tree. However, “words of wisdom” maybe a challenge. Solving noise problems, setting acoustical performance targets and guidelines, and developing noise control systems for new and carry-over vehicles can be very challenging and time consuming particularly in today's culture. In the 1970's and 80's, and 90's we had the same challenges. Our customers demanded and appreciated a quiet vehicle. They want to talk to each other without shouting or to enjoy a favorite music selection regardless of weather, road conditions, or vehicle speed. The use of ear plugs or cotton is not acceptable! Noise Gremlins (Figure 1) can ruin a good day! Management, on the other hand, reasonably requires that we accomplish all of these objectives as soon as possible (yesterday preferred), don't spend any money, design it for easy assembly and above all keep-the-lead-out! Don't add any weight to the vehicle! Did your boss make any of these demands recently?"
A Study of NVH Vehicle Testing Variability,"At certain key stages in the vehicle development process, prototype vehicles are available for NVH testing. This testing fulfills two functions: primarily it is used to assess the status of the vehicle to the program NVH performance targets, but it also provides an opportunity to validate the vehicle SEA model. These single vehicle test events provide a snapshot of the NVH performance but do not provide any understanding of the variability of the NVH performance, which is due to many factors: components, build or assembly and test setup variability. SEA models can be used to estimate the vehicle level variability, if the variability of the interior components is understood, but there is limited data available to confirm the accuracy of these predictions. In this paper we examine the repeatability and reproducibility through a standard gage R&R study of Engine Noise Reduction (engine NR) and Tire NR testing. We also examine the variation in NR from vehicle-to-vehicle through testing on six compact sedans of the same vehicle line. A more limited chassis dynamometer study on three of the six vehicles is also presented to look at typical running vehicle measures such as articulation index, loudness and overall SPL for tire and powertrain noise. Although the sample population is small, we have extracted estimates of variation in body noise reduction due to test setup, actual component and build variation and the implications for predicting variability through SEA models."
Electromagnetic Compatibility of Direct Current Motors in an Automobile Environment,"As the volume and complexity of electronics increases in automobiles, so does the complexity of the electromagnetic relationship between systems. The reliability and functionality of electronic systems in automobiles can be affected by noise sources such as direct current (DC) motors. A typical automobile has 25 to 100+ DC motors performing different tasks. This paper investigates the noise environment due to DC motors found in automobiles and the requirements that automobile manufacturers impose to suppress RF electromagnetic noise and conducted transients."
CAE Virtual Test of Air Intake Manifolds Using Coupled Vibration and Pressure Pulsation Loads,"A coupled vibration and pressure loading procedure has been developed to perform a CAE virtual test for engine air intake manifolds. The CAE virtual test simulates the same physical test configuration and environments, such as the base acceleration vibration excitation and pressure pulsation loads, as well as temperature conditions, for design validation (DV) test of air intake manifolds. The original vibration and pressure load data, measured with respect to the engine speed rpm, are first converted to their respective vibration and pressure power spectrum density (PSD) profiles in frequency domain, based on the duty cycle specification. The final accelerated vibration excitation and pressure PSD load profiles for design validation are derived based on the key life test (KLT) duration and reliability requirements, using the equivalent fatigue damage technique. The coupled vibration and pressure simulation is then implemented by applying both the base acceleration and pressure pulsation loads to the manifold CAE model, in terms of PSD functions, using the frequency response analysis technique. The computer simulation generates dynamic response of the air intake manifold structure, in terms of stress PSD results at identified hotspot locations. The durability life of the air intake manifold design is then evaluated based on the simulated stress and material fatigue damage model. The fatigue damage model is established from fatigue data of the manifold material obtained at different test temperatures. The presented procedure has helped the engineering team to identify potential durability design problems without a prototype, and to guide the design changes and modifications. It has shown that CAE virtual tests provide a way to speed up air intake manifold product development, and to minimize prototypes and costs."
Development of the Vibrational EFA (Energy Flow Analysis) Software EFADSC++ R4 and its Applications to Automobiles,"The Energy Flow Analysis (EFA) offers very promising results in predicting the noise and vibration responses of system structures in medium-to-high frequency ranges. We have developed the Energy Flow Finite Element Method (EFFEM) based software, EFADS C++ R4, for the vibration analysis. The software can analyze the built-up structures composed of beam, plate, spring-damper, rigid body elements and so on, and has many useful functions. For the effectiveness and convenience of software, the main functions of the whole software are modularized into translator, model-converter, and solver. The translator module makes it possible to use of finite element (FE) model for the vibration analysis at low frequencies. The model-converter module changes FE model into energy flow finite element (EFFE) model. It is generates joint elements to cover the vibrational attenuation in the complex structures composed of various elements and can solve the joint element equations by using the wave transmission approach very quickly. The solver module supports the various direct and iterative solvers for multi-DOF structures. EFADS C++ R4 can also use the analytic parameters input by user. The simulation about the local part of real automobile is performed sucessfully."
Diagnostics of Engine Noise During Run-up Using HELS Based Nearfield Acoustical Holography,"This paper describes the diagnostics of noise sources and characteristics of a full-size gasoline engine during its run-up using Helmholtz Equation Least Squares (HELS) method based nearfield acoustical holography (NAH). The acoustic pressures are measured using an array of 56 microphones conformal to the contours of engine surfaces at very close range. Measurements are collected near the oil pan, front and intake sides. The data thus collected are taken as input to HELS program, and the acoustic pressure mappings on the oil pan, front and intake surfaces are calculated. These reconstructed acoustic quantities clearly demonstrate the “hot spots” of sound pressures generated by this gasoline engine during its run-up and under a constant speed condition. These acoustic pressure mappings together with order-tracking spectrograms allow for identification of the peak amplitudes of acoustic pressures on a targeted surface as a function of the frequency and engine rpm. This information enables one to correlate a particular drive train order at a specific frequency and rpm to the peak amplitude of the sound pressure at a specific location on the engine surface, e.g., an oil pan. The depth and breadth of clearly defined information obtained can be very helpful to identify noise sources and how they change with the engine speed."
The Effects of Body Joint Designs on Liftgate Chucking Performance,"Liftgate chucking is one of the major squeak and rattle concerns for vehicles with a large body closure opening in the liftgate area. High frequency chucking noise is generated as a result of the contact between the latch and striker of a liftgate. Traditionally, liftgate chucking problems (if present) are found and fixed by using a more robust latch/striker mechanism at a very late design stage that normally results in cost penalties for vehicle programs. Significant effort has been made at Ford in identifying and clarifying up-front drivers or body performance metrics that predominantly influence downstream squeak and rattle sensitivity. Two key body performance metrics (diagonal distortions at the liftgate opening and relative displacement between the latch and striker of a liftgate) are found to affect liftgate chucking sensitivity. The effects of body joint designs on liftgate chucking performance are discussed using these metrics in CAE analyses. A joint design that balances performance, weight and cost is identified in the process."
On the Relation Between Exposure to Sound and Auditory Performance,"This paper presents the results of 10 years of work on the relation between exposure to sound and its effect on hearing. More than ten thousand persons were examined. Highlights of the results are: (a) a person's everyday exposure to sound can have a beneficial effect on hearing such as reducing the effect of aging and lowering the susceptibility to damage; (b) women are more susceptible to low-frequency noise than men; (c) impulsive sound is particularly dangerous to hearing; (d) three different resonances appear to cause most damage after being exposed to intense impulsive sound; and (e) there is a strong relation between the structure of impulsive sound and damage to hearing. With regard to the effect of the peak sound pressure from airbag deployment, driver airbags are less damaging to the ears than firearms because of masking effects."
An EFEM0-SEA Integrated Model of a Trimmed Van,"High frequency responses of structural-acoustic systems may be predicted by statistical energy analysis (SEA) or energy finite element method (EFEM). To combine the good features of these two techniques, a simplified energy finite element method, referred to as EFEM0, has been developed recently. The EFEM0 technique, which is compatible with SEA, integrates the joint coupling procedures for discontinuous systems and the finite volume formulation for continuous system. The EFEM0 models have been verified either analytically or experimentally for one- and multi-dimensional systems. In this study, the EFEM0 technique is applied to a passenger van for a noise control investigation. The general scheme is to incorporate the EFEM0 coupling factors into a SEA model in order to release some SEA assumptions and improve the SEA model, especially for relatively high damping, strong coupling and direct field cases. The EFEM0-SEA integrated model for the trimmed van is validated by experimental data. Several noise control strategies will be discussed for the integrated model to optimize the sound package."
Sound Package Design for a Convertible by Statistical Energy Analysis,The application of SEA (Statistical Energy Analysis) to the sound package design for a convertible is presented. SEA modeling was used optimize the soft-top construction and the acoustic insulation in the top-stack area (where the soft-top is stored) which were shown to be important transmission paths for tire noise. Correlation between measurement data and predictions from the SEA model is presented and good agreement shown. It is concluded that SEA can be applied to determine the special sound package requirements for convertible vehicles.
Novel Design of a Multi-Function Acoustics Laboratory for the Testing and Evaluation of Automotive Acoustics Systems and Components,"The acoustic performance requirements of vehicle interior trim elements and sound package elements have increased significantly in recent years. Additionally, the burden of developing these products has been shifted from the Original Equipment Manufacturers (OEMs) to suppliers. To aid in developing lightweight, low cost, and high performance parts, a flexible acoustic testing facility was designed for use in many different applications. Specific, purpose-built chambers for only one type of measurement are typically not cost effective facilities."
Towards a Standard for Material Friction Pair Testing to Reduce Automotive Squeaks,"Today vehicle owners perceive squeaks and itches inside a vehicle cabin as a major negative indicator of vehicle build quality and durability. Manufacturers struggle to bear the high costs of squeak and rattle (S&R) related warranty. Although the benefits of structural integrity and tight manufacturing tolerances with respect to the prevention of S&R are known, today's cost, weight, crash requirements, aesthetic demands and environmental/fire hazard rules quite often dictate the design of S&R prone sub-systems. Even sub-systems with the best possible structural design and manufacturing tolerances are not immune to extreme environmental conditions, and mating materials can initiate contact leading to S&R. One method of minimizing the possibility of squeaks is by the judicious selection of mating material pairs. This paper describes a test process aimed at the quantification of material pair compatibility. Also described is a state of the art, flexure-based (virtually frictionless) test instrument that has been developed for such material pair compatibility studies. A group of 17 material pairs with known historical problems were identified by experienced automotive designers and were put through 374 tests encompassing several realistic temperature and humidity extremes in a complex test matrix. Material pair samples were “rubbed together” in an accurately controlled manner. The types of relative displacement that were used were single excursion pull and realistic road inputs in the form of a shaped random profile. The material pairs included combinations of PVC, ABS, TPO, PP and painted metal from sub-systems such as instrument panels, center consoles, body panels, door trim and weather-strips. Instationary Zwicker loudness was used as a metric for quantifying the squeak in addition to classical friction parameters. From the test data, a classification of the material pairs was made pertaining to their propensity to generate squeak and itch (S&I). Initial levels of correlation with GM material experts' classifications of the same pairs are promising and are the motivation for further studies. The Team (Defiance, GM and MB Dynamics) feels strongly about the need for a comprehensive materials database that is the result of a uniform experimental procedure to identify pertinent material characteristics in order to understand, verify and significantly reduce stick-slip in automotive applications. The Team feels that the test equipment, test procedures and analysis methods that were developed during this project and that are described in this paper, greatly contribute towards this cause. The Team wants to extend the invitation to other interested parties (tribology researchers, scientists, automotive or other engineers), to bundle efforts, share best practices and lessons learned, and work towards a standard for material friction pair testing."
Design of a World-Class Vehicle Acoustical Laboratory Facility,"This paper examines the critical design elements and issues associated with converting facility goals and business objectives into a functional facility. The design of the General Motors Noise and Vibration Analysis Laboratory (NVAL) will be discussed to help clarify key points. A team-oriented design approach is essential to meet the stringent safety, flexibility and operational requirements associated with noise, vibration and harshness (NVH) facilities. The first step is establishing the design team and their respective roles in the process. The challenge of “how to build a facility that meets the specified objectives” is addressed in the programming phase. Operational and financial objectives are reviewed and validated. Upon completion of the programming effort, the team attacks the special technical challenges borne out of that process. This is the beginning of the design development phase of the project and involves tackling such issues as acoustic isolation, vibration isolation and HVAC system noise control. The goal is to meet the technical challenges associated with actual facility capabilities and simultaneous testing of different operations within the building. At the conclusion of these critical elements, the design team is prepared to complete the detailed design of the facility and plan for the ensuing construction.(1) This paper offers a summary of the NVH facility design process, as well as key items learned through the course of the GM NVAL design effort."
Development of Windshield Defogging,"South America is traditionally a follow source region where vehicles are mostly developed and validated in the lead development regions with the goal of having a single design applied globally. Most of these developments are proven efficient, which is the case of air conditioning systems, however heating and ventilation systems have particular regional requirements according to details suggested at this paper where we explore regional needs (tropical climate condition) and unique development specifications for windshield defogging."
Wavelet-Based Visualization of Impulsive and Transient Sounds in Stationary Background Noise,"Scalograms based on shift-invariant orthonormal wavelet transforms can be used to analyze impulsive and transient sounds in the presence of more stationary sound backgrounds, such as wind noise or drivetrain noise. The visual threshold of detection for impulsive features on the scalogram (signal energy content vs. time and frequency,) is shown to be similar to the audible threshold of detection of the human auditory system for the corresponding impulsive sounds. Two examples of impulsive sounds in a realistic automotive sound background are presented: automotive interior rattle in a vehicle passenger compartment, and spark knock recorded in an engine compartment."
Validation and Improvement of Body Panels FE Models from 3D-Shape and Vibration Measurements by Optical Methods,"In this paper, we propose a strategy for validation and improvement of structural finite elements (FE) models using vibration and 3D-shape optical measuring method. The main advantage of these methods is to provide a whole field information allowing to speed-up the measurements, combined with an high spatial resolution ensuring updating quality. This strategy is especially adapted to the improvement of light weight body panel structures. Several application examples are presented."
Evaluation of Wind Noise Sources Using Experimental and Computational Methods,"Experiment and CFD have been performed to clarify the distribution of wind noise sources and its generation mechanism for a production vehicle. Three noise source identification techniques were applied to measure the wind noise sources from the outside and inside of vehicle. The relation between these noise sources and the interior noise was investigated by modifying the specification of underbody and front-pillar. In addition, CFD was preformed to predict the noise sources and clarify its generation mechanism. The noise sources obtained by simulation show good agreement with experiment in the region of side window and underbody."
Electromagnetic Compliance Issues of Project Oculus,"Project Oculus, an experimental configurable sensor platform for deploying airborne sensors on a C-130 aircraft, is currently in its pre-flight testing phase. The electronics driving the platform are available commercially off the shelf (COTS) and as such are not automatically rated to comply with stringent military electromagnetic standards as defined in MIL-STD-461. These COTS electronics include efficient switching power converters, variable frequency motor drives (VFD), and microprocessor based equipment, all of which can present electromagnetic interference (EMI) issues. Even in a design where EMI issues were not considered up front, it is often possible to bring the overall configuration into compliance. Switching and digital clock signals produce both conducted and radiated noise emissions. Long cable runs and enclosure apertures become noise transmitting antennas. Large switching currents place noise on the power lines causing interference with other equipment. These problems became apparent during initial EMI compliance testing. This publication will outline the shielding and filtering techniques used to resolve these problems in preparation for flight testing and evaluation."
University of Idaho's Clean Snowmobile Design Using a Direct-Injection Two-Stroke,"The University of Idaho's entry into the 2005 SAE Clean Snowmobile Challenge (CSC) was a second-generation gasoline direct-injection (GDI) two-stroke powered snowmobile. A battery-less direct-injection system was used to decrease exhaust emissions and improve fuel economy without reducing the power output of the engine. A spiral exhaust silencer was used to reduce exhaust noise. Under-hood noise was targeted by using sound absorbing materials and a sealed hood. Chassis noise was addressed by using a spray-on rubberized material that absorbs vibrations transferred through the chassis. Power transfer and space issues were addressed with the addition of a direct-drive system that eliminated the jackshaft. The snowmobile entered into the 2005 SAE CSC competition was lightweight, fun-to-ride, powerful, and had reduced exhaust emissions."
Active Noise Control Simulation in a Passenger Car Cabin Using Finite Element Modeling,"According to the importance of Active Noise Control (ANC) in 3D spaces such as vehicle cabins for reducing unwanted noises inside cabins, the purpose of this paper is to demonstrate the finite element (FE) modeling, simulation and analysis of an ANC in a 3D acoustic passenger car cabin with filtered-X LMS adaptive feed forward controller. For this purpose, after creating an acoustic FE model of the passenger car cabin and calculating its resonance frequencies and mode shapes; several transfer functions of primary, secondary and feedback paths of the acoustic field is estimated in digital domain in accordance with frequency responses obtained from FE model in order to simulate the behavior of ANC system. In all simulations, acoustic feedback effect is considered and the acoustic feedback neutralization technique is used to reduce or overcome the instability potential of this effect. The performance of different configurations of multi-channel “FXLMS” ANC systems is studied with “off-line” modeling technique using Finite Impulse Response (FIR) filters. The obtained results are useful for optimal placement of secondary sources and error microphones. It is found that, the acoustic pressure attenuation inside cabin can be significantly reduced if the control source is placed in close proximity to the reference microphone. However, increasing the number of sensors and/or the number of control sources located remotely from the primary source, have little impact on the maximum achievable reduction in the acoustic pressure in the cavity."
Productive measurement of transmission loss characteristics using Nearfield Acoustic Holography,"A continuously growing demand comes from the automotive industry for optimisation of materials and sound insulating products implementation inside the car, in order to propose the best acoustic performance at reduced costs. As already presented last year at SEA Brazil [9], the approach based on extensive use of the acoustical holography system dBVISION of 01dB-METRAVIB provides part of the solution to such a demand. Whereas the first paper was dedicated to some general considerations and practical aspects of NAH implementation inside a car, the one proposed for the 2005 session is focused on a very important aspect of NAH measurements, namely productivity, for both inside and outside measurements. The paper reviews the NAH technique advantages for measuring the acoustic field inside and outside a vehicle and performing extensive studies on transmission loss characteristics of panels and car openings, with the aim of: detailed localization of possible acoustic weakness points on single components, ranking of the tested components in terms of global and partial radiated power contribution driving possible optimisation of component in the early stages of the design cycle The applied test set-up will be presented and its main features regarding productivity improvement will be highlighted, with a special attention to the compact and versatile robotized instrumentation used for this type of measurements. The presentation will be illustrated by operational results in different situations and some possible extension will be proposed in order to open this technique to the efficient characterization of 3D-shaped structures."
Reference vs. Preference: The “Surround” of Surround Sound,"Surround sound provided by stereo and 5.1 systems may not be satisfying all its listeners. Whether in the automobile or in the home, customers complain of “nothing from the rear speakers”, or about the sound “not filing the room”, etc. While 5.1 systems promise more surround, the economics of music production and concerns of music professionals are likely causing stereo to dominate production resources and causing 5.1 mixes to miss their full potential. The author believes that post-processing electronic and acoustic manipulation can produce sound that customers will prefer. A controlled experiment was performed which compared reference stereo and surround systems to ones augmented by extra surround equipment. This paper: 1 Discusses a very brief history of stereo and surround sound 2 Describes an experiment used to test listener preference, 3 Details experimental results when comparing reference-like music presentation with envelopment enhancing sound processing using both stereo and 5.1 recorded music."
Application of Novel Viscoelastic Microcellular Foams for Passive Noise Control in Automotive Body Structures,"This paper discusses the development of lighter weight, superior acoustic performance and cost effective viscoelastic microcellular foams for the use in automotive passive noise control panels. The study incorporates the control of the foaming process for production of variable microcellular structures and morphologies for the novel foams under investigation. For that purpose, the foaming process was controlled for production of foam samples with various microcellular structures. Cross linked LDPE was used as a base material for the produced foams. Very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9E108 - 1.6E109 cells/cm3) and desired expansion ratios (3 - 9 folds) were successfully obtained. While the material is overly porous, it is noted that the unfoamed skins on the outer surfaces of the samples have prevented sound waves from penetrating the samples. Manual skin removal resulted in slight improvement in sound absorption testing. However, in order to get more reliable data, skinless samples need to be produced."
"Creation of a Brake Development City Traffic Vehicle Test in Shanghai / Suzhou, China","As automotive manufacturing increases in China, boosting the sales of OEM and aftermarket brake system components, it becomes increasingly important to address customer and manufacturer concerns regarding the implementation of localized testing. In response to the growing demand to understand noise and component wear characteristics, research to assess representative city traffic patterns in the city and suburbs of Shanghai/Suzhou, China has been conducted. With this data, a procedure for operating a city traffic vehicle test in China has been developed and documented in this paper. This testing process provides data that quantifies lining and rotor wear, brake energy levels, lining temperatures, component NVH, and other brake system qualities. Through the standardization of this procedure, OEM suppliers, aftermarket vendors, and other interested parties will have the means necessary to execute controlled and standardized vehicle level brake testing which generates data for the purposes of predicting brake wear and noise performance."
Noise Suppression chips in Small Motors,"Expanding the applied frequency bandwidth to include higher frequencies of conducted and radiated electromagnetic interference (EMI), has brought all inductive devices including the small sub-fractional motor to the attention of vehicle manufacturers5. The surface mounted noise cancellation chip can be combined with design strategies to reduce, contain, and attenuate the natural occurring broadband EMI phenomenon in the permanent magnet direct current motor."
Optimization Study for Sunroof Buffeting Reduction,"This paper presents the results of optimization study for sunroof buffeting reduction using CFD technology. For an early prototype vehicle as a baseline model in this study a high level of sunroof buffeting 133dB has been found. The CFD simulation shows that the buffeting noise can be reduced by installing a wind deflector at its optimal angle 40 degrees from the upward vertical line. Further optimization study demonstrates that the buffeting peak SPL can be reduced to 97dB if the sunroof glass moves to its optimal position, 50% of the total length of the sunroof from the front edge. For any other vehicles, the optimization procedure is the same to get the optimal parameters. On the other hand, however, this optimization study is only based on fluid dynamics principle without considering manufacturability, styling, cost, etc. Further work is needed to utilize the results in the production design."
"Crew Protection, Contingency EVA and the Crew Exploration Vehicle","The proposed NASA Crew Exploration Vehicle (CEV) has been labeled “not as a repetition of Apollo, but instead what Apollo should have been.” While this designation is certainly ripe for debate, there is no debating that the space suit community has, up to this point, had limited or no input into the on-going design of the CEV. However, it is important that the community take the opportunity to influence the configuration of the proposed CEV so as to optimize its orbital and planetary/lunar EVA capability, flexibility and safety. This “window of opportunity” will not remain open for long, as the CEV’s configuration is rapidly congealing. This paper covers: 1. Brief space suit configurations, employment and history. 2. Brief descriptions and comparisons of IVA, EVA and IEVA space suits. 3. How history can be a guide to optimize EVA for the Crew Exploration Vehicle."
System Dynamics and Ride Quality Assessment of Automobile,"Ride quality analysis involves the study of three topics: ride excitation sources, system dynamics of a vehicle, human perception and tolerance of vibration. In this study, we establish an integration analysis procedure including the system dynamics analysis and the ride quality evaluation. The dynamic responseof a passenger car was simulated by a multi-body model with ADAMS software. The calculated acceleration responses of seats coincide with the field measured ones. The effect of damping ratio (C), stiffness coefficient (K), vehicle speed and seating location on the acceleration response are also investigated. The ride quality analysis was conducted following the ISO 2631 standard. A LabVIEW computer code was developed to provide fast and convenient assessment of the comfort. A 3-axis translational accelerometer was installed on the seat. The responses of a passenger car traveling on the long wave road, asphalt uneven road and stepped joint road of proving ground in ARTC (Automotive Research & Testing Center in Taiwan) were collected. A satisfactory agreement was observed between the comfort index obtained on the experimental data and dynamic simulation."
Development of a Lightweight Sound Package for 2006 Brand-New Vehicle Categorized as C,"This paper describes an effective method of developing a soundproof package, which balances both light weight and high noise insulation performance. Since it is required to propose design of sound insulator in the early stages of the development, the hybrid statistical energy analysis (SEA) modeling method is applied, which is practical for high frequency analysis. Also an acoustic characteristic estimation technique of the multi layer structures is used. As a result of applying these effective methods, the 2006 brand-new vehicle categorized as C has enhanced in road noise quietness and decreased in weight as compared with the previous model."
The Armageddon Device Part II,"Applying good engineering practices to software-intense automotive systems can save automakers millions of dollars in warrantee costs, lost customer loyalty and lawsuits. Carefully crafted development testing could expose non-robust software that fails intermittently when the customer activates the function. The chances are very good the service technician will replace the ECU when the customer brings the vehicle in for repair of the intermittent behavior. These electronic parts are sent to the supplier for analysis. Upwards of 60% of all ECUs analyzed are TNI (Trouble Not Identified) related. This paper elaborates on a method of developmental testing that provides these cost savings. This paper continues to build on concepts discussed in the SAE paper, “The Bus Crusher and The Armageddon Device Part I”. [1] The experiment of subjecting an ECU to several electrical disturbances is explained in detail. The objective of an embedded system is to have a predictable output for any combination of input sequences. If the operation of the embedded system is viewed as a big state diagram, testing verifies that the embedded system operates in acceptable states and that transitions between states are all known and predictable. The stress-testing concept described in this paper generates sequences of stimuli that can’t normally be planned for (the number of combinations is massive). The embedded system must always remain in a known acceptable state, regardless of the stimulus. The testing techniques described allows for the creation of a stimulus to verify the robustness of the embedded system. Experiments were conducted on electrical breadboards, which were subjected to RF (Radio Frequency) noise, periodic network initialization, communication bus failures, intermittent ground open, and repeated cycling of the locking function. The hypothesis of the experiment was to stress the ECU’s operating environment by causing events that seldom occur, and make them happen with high regularity. The electrical noise level is below the ECU design limit, e.g., the task monitoring the ECU voltage range will ignore voltage drops of less than 15 msec (milliseconds). Subjecting the ground circuit to an interruption of less than 15 msec should result in no humanly perceivable behavior change. Methods to stress the software are the focus of this document. Described are: 1. Building the RF Blaster 2. Building the Armageddon Breakout box 3. Introducing new noise factors; ground lift and periodic network initialization 4. Lock-Unlock Cycle test 5. Results of the tests"
Investigation of the perceived sound quality of an automotive HVAC system,"The noise emitted by the heating, ventilation and air conditioning system (HVAC) has a great influence on the car acoustical comfort and quality perception. To improve its sound quality, physical properties which determine the subjective perception have to be identified. The HVAC-noise of twelve cars in different arrangements of fan speed and direction of air flow was recorded for later objective and subjective analysis. All cars were of the same model, but with three different types of HVAC-systems, and had just been manufactured. Objective analysis with sound quality software and subjective evaluations was carried out. Using multiple linear regressions on the subjective data, relations between subjective results and psychoacoustic metrics were determined and models to predict subjective response to HVAC sounds are proposed. It is shown that the annoyance caused by the HVAC-noise can be satisfactorily described by Zwicker's stationary loudness model."
In-Vehicle Panoramic Noise Source Mapping,"For many years engineers in the automotive market have struggled to find ways to accurately and efficiently map the noise sources found inside a vehicle. Many techniques, both theoretical and measurement based, have been proposed and used, but there has always been a trade off between accuracy and efficiency. Techniques like sound intensity mapping and Statistical Energy Analysis have proven to be accurate when mapping noise sources in vehicle, but require a large investment in time and money to create a simple, easy to interpret picture showing where dominant noise sources come from. In this paper the authors will introduce and demonstrate a novel technique, spherical beamforming, which can overcome the issue of test time and produce fast, accurate noise maps from the interior of a vehicle."
Investigation on the Acoustic Performance of Current Trunk Load Floor Solutions,"Different solutions for trunk floors recently presented on the market have been collated and investigated in order to better define the possible features integrated and the acoustic performance of trunk load floors. A description protocol has been devised and applied to systematically categorize the whole set of features potentially characterizing a trunk floor, and the wide range of solutions used with respect to materials, processes and design configurations. The acoustic performance has been specifically addressed with the evaluation of the acoustic absorption on both sides and a specific testing procedure to evaluate the noise insulation capability provided by actual parts. The results of the actual parts acoustic performance measurement campaign show that a substantial improvement in the acoustic function of the trunk floor module can be achieved by the systematic choice of materials, processes, and of the geometry of the part, in compliance with the standard OEMs requirements Some solution trends for vehicle architecture and segment are highlighted, and recommendations to enhance the acoustic performance and the functionality of trunk floors are provided."
FEA Design of a Vibration Barrier to Reduce Structure Borne Noise,"In the low frequency range, mechanical vibrations propagate into the car body by structure borne transmission. In order to limit this transmission, an original system called “Vibration Barrier” has been developed. It reduces the vibrations propagating into the hollow body network (the transmission path) using a cavity part and the high damping foam technology. This paper describes the general concept and the FEA design process of a Vibration Barrier part. An example is given for a full car body. The best compromise of the tested designs leads to a significant reduction of the structure borne noise using a lightweight part."
Combining an Energy Boundary Element with an Energy Finite Element Analysis for Airborne Noise Simulations,"The Energy Boundary Element Analysis (EBEA) has been utilized in the past for computing the exterior acoustic field at high frequencies (above ∼400Hz) around vehicle structures and numerical results have been compared successfully to test data [1, 2 and 3]. The Energy Finite Element Analysis (EFEA) has been developed for computing the structural vibration of complex structures at high frequencies and validations have been presented in previous publications [4, 5]. In this paper the EBEA is utilized for computing the acoustic field around a vehicle structure due to external acoustic noise sources. The computed exterior acoustic field comprises the excitation for the EFEA analysis. Appropriate loading functions have been developed for representing the exterior acoustic loading in the EFEA simulations, and a formulation has been developed for considering the acoustic treatment applied on the interior side of structural panels. In order to demonstrate how the new developments can be combined in airborne noise applications, a case study is presented."
Tire Noise Reduction with Fiber Exterior Wheel Arch Liners,"Tire noise reduction was evaluated with acoustically designed exterior wheel arch liners. The wheel liners were made with a fiber blend selected to meet acoustical requirements, process demands, and durability challenges. Fiber liners were installed in a vehicle and noise level measurements were made under a range of operating conditions. The results show the reduction in tire noise that can be achieved at the source and in the vehicle. A critical part of this evaluation was a rapid analysis technique to select metrics that correlated with subjective assessments. The analysis techniques also helped quantify the improvements over a baseline condition."
Microcellular Ceramic Foams: Manufacturing and Study of Acoustical Properties,"A novel processing method for fabricating high porosity microcellular ceramic foams for sound absorption applications has been developed. The strategy for fabricating the ceramic foams involves: (i) forming some shapes using a mixture of preceramic polymer and expandable microspheres by a conventional ceramic forming method, (ii) foaming the compact by heating, (iii) cross-linking the foamed body, and (iv) transforming the foamed body into ceramic foams by pyrolysis. By controlling the microsphere content and that of the base elastomer, it was possible to adjust the porosity with a very high open-cell content (ranging between 43 - 95%), high microcellular cell densities (9 × 108 - 1.6 × 109 cells/cm3) and desired expansion ratios (3 - 6 folds). Sound absorption testing has been performed using ASTM C-384 standard test. The preliminary results show that ceramic foams are candidate sound absorption materials."
Evolution of Fiber Felt Technologies and Composites Enhancing Vehicle Acoustics,"For generations, fiber felt technologies have been used as a building block in the development of various absorbers and decoupler composites used for automotive acoustics. This development has led to a variety of felt components with increasing complexity in their differentiations. This paper will review the evolution of three generations of felt technologies. Generation 1 and 2 will discuss needled, resinated, and thermoplastic fibers bonded felts by comparing various performance indexes from physical parameters of raw materials, manufacturing processes, product applications and physical characterization along with acoustic properties. Generation 3 will introduce strategies, technologies, and approaches to further simplify the multitude of fiber felt innovations."
Product Sound Quality of Vehicle Noise – A Permanent Challenge for NVH Measurement Technologies,"Sound quality of vehicle is more and more an important product feature which significantly influences the perceived product quality. Over recent years, the broad variety of new models, which resulted in increased competition, has lead to rising customer demands with regard to NVH (Noise, Vibration and Harshness) aspects. Apart from the indispensable troubleshooting, the acoustic engineer's scope of work is extended to NVH design engineering. Thus, innovative, ambitious measurement technologies were developed to meet these new, challenging tasks and to maintain a competitive advantage."
Calculations of Wind Tunnel Circuit Losses and Speed with Acoustic Foams,"The GM Aerodynamics Laboratory (GMAL) was modified in 2001 to reduce the background noise level and provide a semi-anechoic test section for wind noise testing. The walls and ceiling of the test section were lined with acoustic foam and foam-filled turning vanes were installed in the corners. Portions of the wind tunnel circuit were also treated with fiberglass material covered by perforated sheet metal panels. High skin drag due to roughness of the foam surfaces, along with high blockage due to the large turning vanes, increased the wind tunnel circuit losses so that the maximum wind speed in the test section was reduced. The present study calculates the averaged total pressure losses at three locations to evaluate the reductions in skin drag and blockage from proposed modifications to the circuit, which were intended to increase the test section wind speed without compromising noise levels. The effect of foam roughness, characterized by measurement of the boundary layer displacement thickness, was incorporated into CFD models with effective-viscosity and inner-wall-log roughness models. The mathematical correlation of the reduction of total pressure loss with the increase of test section speed is presented to justify the proposed circuit modifications. The projected reduction in the circuit total pressure loss coefficient from 0.54 to 0.44 is in good agreement with the tests."
Dynamic Door Component Test Methodology,"This paper describes the development of a Dynamic Door Component Test Methodology (DDCTM) for side impact simulation. A feasibility study of the methodology was conducted using a MADYMO computer model by taking parameters such as door pre-crush, door-to-SID (Side Impact Dummy) contact velocity and the deceleration profile into consideration. The prove-out tests of this methodology was carried out on a dynamic sled test facility. The DDCTM has been validated for various carlines. In addition, various existing dynamic component test methods are reviewed. In our approach, a pre-crushed door, mounted on a sled, strikes a stationary SID at a pre-determined velocity. A programmable hydraulic decelerator is used to decelerate the sled to simulate the barrier/door deceleration pulse during door-to-SID contact period. This test procedure provides excellent correlation of the SID responses between the component test and the full-scale vehicle test. The DDCTM significantly reduces the time and resources required for developing improved side impact protection systems, including new door/trim, side air bag systems and padding material evaluation. This methodology has been applied to the development of the Ford Deploying Trim System."
Glazing Effects of Door or Frame Deformations in Crashes,"1990 Geo Prism front door side tempered glass windows 3 mm thick were slowly bent, or shock loaded, to failure, with the glass clusters and fragments then found as large as 13 x 10 cm, weight to 42 grams, with some sharp points and slivers, and speed of release from the glazing surface of intermediate size pieces to 23 km/h. The fracture patterns of the tempered glass bent or shock loaded to failure were often oblique rather than perpendicular, in comparison to the patterns of an unloaded tempered glass broken by a locally applied sharp pointed object. This explains the sharpness and many lacerations of tempered glass shattered in road crashes, often under conditions of bending or shock loading of the edges of the glazing before it fails. Modification of Federal Motor Vehicle Safety Standard 205 to include fragment studies and laceration effects are suggested."
Front and Side Brake Lights,"Most applications in the ever-expanding automobile safety arena can be categorized in one of two ways: (a) accident prevention and (b) occupant protection. This is for accident prevention. With this application there will be 360 degree brake lights on a vehicle; two units mounted on the front of the vehicle below the vision of the operator, one on each side and a unit mounted on the right and one mounted on the left side of the vehicle in front of the front door and behind the front fender well (preferred location). All of the rear (red), front (blue), and both sides (blue) are energized to emit light 360 degrees when the brake system is applied."
Seamless Passenger Side Air Bag Doors,"Passenger side air bags have been rapidly accepted by the public for the protection they provide; however, in exchange, they have created an issue with fit and finish detracting from the harmony and flow-through styling presently in vogue in vehicles. With the current plethora of materials and processes used to manufacture separate passenger side air bag doors and the inability to build components to a line on line fit, attempts to tune all these factors is a lesson in frustration. In 1992, a design and development team from Textron, Chrysler, Dow, and Allied Signal were given the assignment of making the 1996 Voyager/Caravan the industies first fully integrated seamless passenger air bag (PAB) door. Several critical factors had to be addressed: 1) split seam appearance 2) pab deployment at all temperatures 3) instrument panel integrity 4) customer abuse 5) head impact 6) manufacturability 7) foam retention As a result of their effort, a padded surface instrument panel without any visible seams over the PAB, was implemented into production on the 1996 Chrysler Voyager and Plymouth Caravan models. A vinyl skin is cast with a preferentially weakened section to allow predictable tearing during air bag deployment. The shell is processed using conventional means to provide an instrument panel with a mid-mount PAB canister and an insert molded plastic/steel door that has no distinguishing features to indicate where the bag will deploy. This provides a seamless flow-through appearance, optimizing color, gloss, grain and dimensional match."
Aerodynamic Simulations by Using Discontinuous Interface Grid and Solution Adaptive Grid Method,"Aerodynamic simulations of automobiles with an airflow type rear spoiler (a spoiler that guides part of the flow on the roof onto the rear window of a one-box or two-box car to reduce the adhesion of snow or dust on the rear window) using a discontinuous interface grid method and around a rear view door mirror using a solution adaptive grid method are presented. These new methods have made it possible to capture the detail phenomena around equipment items such as spoilers and door mirrors, thereby improving the accuracy of the CFD (Computational Fluid Dynamics) simulations and shortening the time required."
A Sound Quality System for Engineers,"In the eighties, the main concern in the automotive industry from a designer's standpoint was a level issue. In the nineties, the market has put more stringent requirements on the automotive industry with respect to noise in general and psychoacoustics. The governments have imposed lower limits with respect to pass-by noise standards. Customers are spending more time in their car than in the past and are demanding acoustical comfort. All of this is leading to an environment where a sound quality system is becoming a daily tool in the design and trouble-shooting world. This paper describes what should be looked for in a sound, how to quantify these properties and what tools are needed. These steps are then applied in a case study."
The Perfectly Silent Car - An Engineering Goal?,"A look at the car development of today shows that even strictly cost oriented cars try to give their customers comfort and calm riding. High value cars explain themselves as a substitution for your home when you are on the road. Even from the environmental point of view, people, governments and many associations claim for more reduction of the noise emitted by vehicles. So can it be really a question that the main scope of engineering should be the development of cars as silent as possible? Noise or sound is something that is present even if it seems to be silent. Information are exchanged and emotions controlled. The answer to the above question is not only a technical one but also is touched by marketing and political issues. On the way through the global vehicle noise vibration and harshness (NVH) the following lecture shows that sound design and engineering, acoustic quality, customers expectations and noise legislation are the important areas to define the noise behavior of a car."
Development of a Power Window Switch with Improved Ergonomics,"This paper explains a methodology to develop a Power Window Switch (PWS) that is easy to operate. Many PWS knobs use a pivot movement. The most popular shapes are: 1.Pull-up/Push-down, 2.Rocker, and 3. Toggle. In the Pull-up/Push-down PWS, the knob motion matches the window motion. Since the design of the knob prevents an object or a part of clothing from catching, and pulling the knob up, potential injury from the window coming up is avoided. The knob top surface of the pull up PWS is pushed down to open the window, and the knob front surface is pulled up to close it. One weakness of this design is that the operating finger posture changes each time the window direction changes, the finger will often become tired with the repetitive posture changes. Another weakness of the Pull-up/Push-down PWS is the flush top surface of the knob to the bezel. The size of the knob and corresponding finger well limits the size of the finger and length of the fingernail."
Design for Automotive Glass Removal Using Active Disassembly,"Active Disassembly is a well researched technique for creating assemblies or casings that can break themselves apart for recycling using a heat trigger. ‘Chiodo’ has applied this principle to consumer electronic goods since the mid nineties. In response to pending EU legislation, the scope of active disassembly has broadened to include automotive disassembly. The first automotive demonstrators produced have been to make self-disassembling window glass retaining channels that enable easy glass removal for recycling. This waste glass can then be used in coastal defences as an alternative to landfill. Both shape memory alloy and shape memory polymer solutions have been examined. The shape memory alloy solution has been successful. Optimisation for the polymer solution is required."
Glazing for Vehicle Interior Noise Reduction,"As noise levels within vehicle cabins continue to be reduced, wind noise and traffic noise transmitted through the glazing increase in importance in the quest to achieve further reduction. With consumers ranking cabin noise as an important factor in vehicle purchase decisions, and with the projected increase in vehicle telematics, including speech recognition systems, the need for even quieter interiors will continue. NVH engineers have not recognized that vehicle glazing offers an effective option for noise reduction; often, only monolithic glass has been considered, where the only option for improvement has been to increase the mass (increasing the thickness and the vehicle weight). This paper presents sound pressure loss data for laminated glass compared to the tempered glass typically used for side, rear and roof glazing today. The sound pressure loss results show a significant opportunity for improvement in the 2000 to 6000 Hz region, a key range for human conversation and the key range for wind noise. Along with this acoustic improvement is a reduction in mass of the glazing."
Increasing Performances by Using Multi-Thicknesses Blanks,"Multi-thickness blanks (MTB) enable the dimensional optimization of steel parts by modulating thickness and mechanical properties. Traditionally, this is done by the addition of reinforcement to the basic part after the drawing of both. With MTBs, we first assemble the two flat blanks to obtain a single blank, which is then drawn without further assembly. MTBs comprise the Tailored Welded Blank (TWB), already widely used in automobiles, and a new category “Patchwork”. The TWB is a butt-welded assembly of two blanks with neither overlap nor superimposition. The patchwork blank is made by either the adhesive bonding or welding of a blank onto the surface of the base blank, at the point to be reinforced. These products enable the increase of performance objectives (impact, rigidity, vibration and fatigue resistance, etc.) whilst permitting weight reduction and thus adding to the potential of high resistance steels. They also enable, in numerous cases, the reduction of overall costs. Examples of applications are; side members, shock towers and pillar reinforcements. Illustration of design principles permitting the better understanding and exploitation of MTB potential are shown in this paper."
3D Inside Vehicle Acoustical Holography,"A continuously growing demand comes from the automotive industry in order to get an experimental tool allowing for the optimization of materials and sound insulating products implementation inside the car, so as to propose the best acoustic performance at reduced costs. The acoustical imaging system LORHA provides part of the solution and its demonstrated capability of measuring the acoustic field inside a vehicle makes it an advanced tool for performing extensive studies of the acoustic transparency of car openings. This paper focuses on the methodology and recent operational results obtained within the tight collaboration established between METRAVIB RDS, its partner HUTCHINSON and well known car manufacturers."
Trends and developments in Automotive Glass Encapsulation with PUR materials,"The encapsulation of automotive glassparts started mid '80. It was a step forward in an attempt to supply ready-to-mount glass parts to the automotive production lines. These encapsulated glassparts have a moulded gasket all-around the periphery. Encapsulation can be done with different materials. In this lecture we will focus on the use of polyurethane (PUR) - more specific aliphatic polyurethane - and make a comparison with other materials such as PVC, TPE and EPDM. Since that time, encapsulation has really evolved from the original design function, towards a medium where more and more other elements can be integrated into the window. This can be combined with the fact that today large, complex and even laminated windows need to be encapsulated. Due to these functional integration opportunities the overall cost can be reduced combined with a much larger freedom of design and esthetics."
Welding of Energy Management Systems and Air Duct Systems to Headliner,"This paper reviews the use of vibration welding for joining crash impact pad's and air duct systems to headliner. Increasing government regulation and the evolution of automotive safety are demanding a new innovative welding technology for crash impact pad's as well air duct systems to the headliner. Vibration welding is an approved welding technology to join both similar and dissimilar materials and is used in many automotive applications is an innovative solution for such headliner applications. Driven by customer needs, energy management is an important consideration in protecting the occupants of a vehicle from injury in a crash situation. Air ducts are becoming more and more important to distribute air to the rear passenger. In this case both are placed between the headliner and the roof of the vehicle. Not only does vibration welding produce major cost savings, which is related to no consumables (no adhesive required), but also improves product quality, which means no smelling (no fogging through adhesive), and also provides higher pull off strength without variance with temperature is important in competition."
“Active Mass Absorber” at a 4×4 Transmition System,"The extensive use of rotative machines in the diverse branches of the modern world has made the rising undesirable mechanical and acoustic vibration levels to be a problem of special importance for the machines normal operation as for the communities that are each time more affected by the problem. It makes the study of vibration and acoustic phenomena also to be even more important and the applications of its concepts more sophisticated. Several are the concepts used for decreasing vibration levels, like common dampers, hydraulic dampers, active dampers, natural frequencies changes and others. The choice of use of one or another depends greatly on the engineering possibilities (weight, energy, physical space, other components functional interference, vibration levels, etc.) as well as the cost of implementation of each one. As a general rule, normal dumpers is usually the best method to decrease vibration levels, because of the smaller prices and not often collateral undesirable effects. In this work is presented a problem of vibration of the powertrain system of a 4×4 car that could not be easily solved by the use of normal dumpers and therefore another vibration-decreasing concept has been used: the “Active Mass Absorber”. “Dynamic Absorber” is a concept based on a phenomenon related to one specific vibration absorption by one auxiliary vibrating system attached to the main system, which the vibration level is wanted to be decreased. It works as it was draining the vibration movement of one specific frequency, so the main system vibration level decreases and the attached system (active mass damper) vibrates. In a normal car there are several exciting vibration and acoustic sources, such as the engine, tires, road roughness, air intake and exhaust system. The active mass absorber concept, which is designed for one only frequency absorption, is not an effective approach for the general vibration and acoustic problem solution. In the present study, however, the second order engine vibration was detected to be transmitted to the rear part of the car by the driveshaft and resonating in the back seats area. This resonation caused high sound pressure levels inside the vehicle and could not be decreased by normal dampers between the rear differential and the vehicle body. The solution proposed to this problem was attaching an active mass damper to the rear differential that absorbs part of the vibration energy before it flows to the car body."
Application of LIN Network Interface for Ford South America Vehicles,"Some communication buses are too powerful and expensive for simple digital on/off operations such as activating lights, wipers, windows, etc. For these applications the LIN bus is currently the most promising communication protocol across the world's automotive industry. This paper addresses a study using LIN (Local Interconnect Network) for Ford South America vehicles. This will propose a new electrical architecture designed with LIN network, which will be replacing the conventional rear and front lights cables in Trucks, where other higher protocols, such as CAN, are not cost effective. LIN is a new low cost serial communication system intended to be used for distributed electronic system that will allow gaining further quality enhancement and cost reduction on cables, connectors and switches."
NVH Highlights and (Pot)Holes 1972-2001,"The NVH performance of motor vehicles has been improved dramatically during the 1972-2001 period. The paper identifies the main advances made, i.e. the development highlights and indicates a number of points where a lot of work still needs to be done (Holes or with and automotive flavor “Potholes”). The paper is structured as indicated below. 1 Introduction 2 Highlights 2.1 Vehicle 2.1.1 Body rigidity 2.1.2 Body leakage 2.1.3 Engine efficiency and vibration isolation 2.1.4 Suspension systems 2.2 Noise Control proper 2.2.1 Passby noise treatment and Aerodynamics 2.2.2 Interior treatment simulation and optimization 2.2.3 Noise Control material improvements 2.2.4 Multi-functional parts 2.2.5 Dissipative treatment packages 2.2.6 Noise Quality engineering 2.2.7 Development Methodology: Benchmarking 3 (Pot)Holes 3.1 Modeling car subsystems 3.2 Optimization; application to ever-larger subsystems 3.3 Simulation and Optimization of Passby Noise 3.4 Diagnostics 3.5 Materials and Shapes 3.6 Understanding the vehicle development process"
Improved Methodology for Dynamics of Orbiter Payload Bay Doors,"The Payload Bay Door Dynamics Simulation (PBDS) computer program simulates the mechanical behavior of the space-shuttle payload bay doors and their latching and driving mechanisms during opening, closing, latching, and unlatching. PBDS was developed to replace an older program that was computationally inefficient and that simulated the door hinges incorrectly. In PBDS, the large system of dynamical equations of the payload-bay-door system is decomposed into smaller systems of dynamical equations at the mechanism level. This decomposition involves decoupling through neglect of the inertial parameters of the driving and latching mechanisms, which are small relative to those of the doors. The equations of motion of the doors, which are flexible, are derived by use of a Cartesian flexible-body formulation. The equations of motion of the mechanisms are derived by use of an efficient recursive formulation. Though decoupled dynamically, the door and the mechanisms are coupled kinematically. In solving the mechanism equations, the responses of the door at points where the door is attached to the mechanisms are fed as inputs to the mechanism equations. The outputs of the mechanism equations are forces and torques, which are fed back to the door equations to complete the computational cycle."
Ford looks to spread Corning's new lightweight Gorilla Glass beyond the 2017 GT,"While many supercar enthusiasts have “gone ape” over the Ford 2017 GT, the program development engineers have done the same for a new lightweight glazing solution. Called “Gorilla Glass,” the three-layer laminate is claimed by its supplier, Corning Inc., to deliver more than five times the strength, pound for pound, of conventional automotive glass while offering significant mass reduction. In the case of the GT, more than 12 lb (5.4 kg) was saved by using Gorilla Glass in three areas: the windshield (first use for a production vehicle), the rear window, and in an acoustic separator in the rear bulkhead. It also helped reduce the car's center of gravity by 3 mm (0.12 in)."
Opel designs a new Astra,"Opel launched the fourth-generation Astra at the 2015 IAA (Frankfurt Motor Show). The car is more compact than the model it replaces and weighs up to 200 kg (440 lb) less. A five-door hatchback and five-door Sports Tourer estate were on display at the show. The Astra (a Vauxhall in the U.K.) will be the first vehicle to feature General Motors' OnStar Connectivity system in Europe and comes with the option of matrix LED headlights, which Opel claims is the first time this feature has been offered on a European C-segment car."
Automotive Engineering International 2005-03-01,"Production preview from Detroit Attendees of the 2005 North American International Auto Show in the ""Motor City"" this January were treated to nearly 70 vehicle introductions, 24 of which were worldwide production cars and trucks. AEI editors present the technical highlights of some of the more significant 2005 and 2006 production vehicles. Significantly this year, the cars we've highlighted outnumber trucks by more than two to one. DSPs start progressing Math processors will help to provide more functionality in the cabin and improve motion contorl throughout the vehicle. Sliding doors the Toyota way Door openings are about more than hinges and pillars, according to the Japanese automaker. Accelerating technology Hybrid technology is gaining in popularity, broadening its scope to embrace performance, and driving industry collaborations. SAE 2005 World Congress preview General Motors is host company of the April 11-14 event, and has high expectations for its success in SAE's centennial year. Design ""demarqueation"" PSA's new design center will improve collaboration between teams while preserving individual brand identity, according to the company. Connected SAE 100 Future look: When an automotive designer is asked to envision a vehicle of the future, the response is likely to be, ""Define the society of the future and I can create a vehicle responsive to that society."" Tomorrow's smart car will make drivers better, smarter SAE 100 Future look: Driving on today's expressways is as dangerous as ever. Drivers face the daily challenges of extremely congested roads and distractions from cell phones, passengers, and even in-vehicle DVD systems. Powertrain electronics: a systems evolution SAE 100 Future look: Market forces, driven by consumer and regulatory demands, coupled with advances in technology, have created tremendous opportunities for engineering innovation. Telematics to focus on OEM ROI SAE 100 Future look: It is no secret that a couple yearas ago many in the automotive industry wrote off telematics as a dead issue. That chapter has long since passed, and what you will see emerge in the coming years is a reborn telematics industry that has little resemblance to what we have seen in the past. A gateway to the connected car SAE 100 Future look: Each generation of cars has not only brought drivers sleeker designs and more powerful engines, but also more advanced electronics in the form of features such as satellite radio and navigation. Testing resources This special edition of Product Briefs highlights some of the latest equipment used to develop cleaner, quieter, and safer vehicles."
Improved Design for Manufacture in Minivan Body Systems,"The design for manufacturability process has been recognized as a very effective method for improving the overall quality in mechanical product design. The first part of the paper deals with an extended DFM which encompasses all the various Quality issues in product development. The importance of the three major elements quality, cost and timing are highlighted in the mathematical model for Design for Quality (DFQ). The second part of the paper describes the application of DFQ in the design and development of minivan body and interior systems. The best value of the DFQ is recognized when the process is used proactively during the early stages of the development cycle. Such is the case of the applications discussed in this paper which covers the following systems: hood assembly, seamless door system, sliding door system, instrument panel and message center installation, and fuel filler door-and-housing system."
Comparison of Airbag-Aggressivity Predictors in Relation to Forearm Fractures,"Four unembalmed human cadavers were used in eight direct-forearm-airbag-interaction static deployments to assess the relative aggressivity of two different airbag modules. Instrumentation of the forearm bones included triaxial accelerometry, crack detection gages, and film targets. The forearm-fracture predictors, peak and average distal forearm speed (PDFS and ADFS), were evaluated and compared to the incidence of transverse, oblique, and wedge fractures of the radius and ulna. Internal-airbag pressure and axial column loads were also measured. The results of this study support the use of PDFS or ADFS for the prediction of airbag-induced upper-extremity fractures. The results also suggest that there is no direct relationship between internal-airbag pressure and forearm fracture. The less-aggressive system (LAS) examined in this study produced half the number of forearm fracture as the more-aggressive system (MAS), yet exhibited a more aggressive internal-pressure performance. Both the peak-internal pressure and the initial-inflation rate of the LAS were higher than for the MAS, but the PDFS, ADFS, and axial column loads of the LAS were lower. This inverse relationship between internal-airbag pressure and airbag aggressivity prompted an investigation of the LAS and MAS design characteristics. The closed-module design of the LAS, coupled with longer, thicker tear seams, results in higher peak-internal pressures and greater rates of pressure increase when compared to the MAS. Therefore, more inflator energy must be used to achieve bag egress from the LAS module, making less energy available to be imparted to a forearm. The reduced and more distributed mass and size of the LAS doors may assist in the reduction of focused energy transfer to a forearm and the less-aggressive-tank-test characteristics compared to the MAS inflator. A combination of these factors causes a reduction in the level of fracture predictors, such as PDFS and ADFS, when using the LAS, and a reduction in the incidence and severity of forearm fractures."
Preliminary Studies on the Effects of Injection Rate Modulation on the Combustion Noise of a Common Rail Diesel Engine,"The present work deals with tests on a DI Diesel engine equipped with two different types of Common Rail injectors, the second one allowing a “smoother” fuel rate in the first stage of injection. The work aims at understanding how injection parameters and different injection rates may affect the combustion process in terms of in-cylinder pressure, noise and vibrations of the engine block. The tests performed for the same engine torque generally showed that engine speed, injection pressure and pilot injection duration are the most significant parameters that affect engine noise emissions. As regards the injection rate modulation, experiments showed that it is possible to reduce combustion noise at low engine speeds if the initial rate of injection is lower during the first stage of injection."
Friction-Induced Vibrations of Window Sealing Systems,The problem of squealing from vehicle windows opened or closed in partly wet conditions has been investigated. Experiments were conducted using a glass-run seal sample and a tangentially moving glass piece installed on a test bench. The instantaneous velocity of the glass was measured along with the total dynamic frictional force for varying normal static loads and sprayed-water distributions. The characteristics of squeal vibrations and the influence of normal load and water distribution are discussed. The relation between friction force and speed was also investigated. An idealized model consisting of a one-dimensional continuous rod excited by a moving frictional point force was then investigated. The method of averaging was applied to solve the nonlinear equations of motion. The response became unstable when the magnitude of the negative slope and the normal force were large regardless of boundary conditions. Frequency jumps appeared in the numerical simulations due to the variation of the modal amplitudes according to the position of the contact force on the rod. The model provided an adequate qualitative description of many of the trends observed in the experiments.
Door Courtesy Switch,"This SAE Recommended Practice defines the test conditions, procedures, and performance requirements for 6, 12, and 24 V Door Courtesy Switches which are intended for use in motor vehicles."
Automotive Manufacturing Task Analysis: An Integrated Approach,"Automotive manufacturing presents unique challenges for ergonomic analysis. The variety of tasks and frequencies are typically not seen in other industries. Moving these challenges into the realm of digital human modeling poses new challenges and offers the opportunity to create and enhance tools brought over from the traditional reactive approach. Chiang et al. (2006) documented an enhancement to the Siemen's Jack Static Strength Prediction tool. This paper will document further enhancements to the ErgoSolver (formerly known as the Ford Static Strength Prediction Solver). These enhancements include integration of: Jack's Low Back Analysis tool; a modified Rohmert equation for muscular fatigue analysis; strength scaling equations to account for frequency and duration; the initial HUMOSIM Framework (Reed et al., 2006) for standing posture prediction; an automated measuring tool for common human-related measurements; vision windows and head/eye behavior settings; and Excel and PowerPoint reporting capability. Some of the functionality integrated into the ErgoSolver is existing Jack functionality. The goal of integrating these features was to ease the learning curve and increase efficiency for new and experienced users alike. Attempts were made to bring together, organize and present commonly used functionality in a fashion targeted towards the assembly ergonomics professional. Where functionality gaps were found in Jack, new functionality was created and integrated. While some of these features are pure usability features (i.e. shortcut methods for performing routine tasks), others are based on new and emerging research."
Development of a Broad Delta Airframe and Propulsion Concepts for Reducing Aircraft Noise around Airports,"This paper describes the impact of noise on the civil aircraft design process. The challenge to design ‘silent’ aircraft is the development of efficient airframe-engine technologies, for which integration is essential to produce an optimum aircraft, otherwise penalties such as higher fuel consumption, and, or noise are a concern. A description of work completed by Cranfield University will cover design methodologies used for a Broad delta airframe concept, with reference to future studies into alternate concepts. Engine cycle designs for ultra-high bypass ratio, constant volume combustor, and recuperated propulsion cycles are described, with a discussion of integration challenges within the airframe."
Analytical Simulation of the Effects of Noise Control Treatments on an Excavator Cab using Statistical Energy Analysis,"The objective of this study was to utilize Statistical Energy Analysis (SEA) to simulate the effects of a variety of noise control treatments on the interior sound pressure level (SPL) of a commercial excavator cab. In addition, the effects of leaks on the SPL of the excavator cab were also investigated. This project was conducted along with various tests that were used to determine the inputs needed to accurately represent the loads that the cab experienced during operation. This paper explains the how the model was constructed, how the loads were applied to the model, the results that were obtained from application of treatments, and a study of the effects of introducing leaks to the cab structure in the SEA model."
ECoustics -- Vehicle Sound Package Inspired by Environmental Design,"The environmental issues are mounting for a global automotive industry associated with ever-increasing output. Major issues include fuel consumption, vehicle emissions, consumption of non-renewable materials, and recycling of waste materials. This paper provides an overview of recent advances in new acoustic materials based on recycled and sustainable sources for “environmental” vehicle sound packages that address NVH and trim acoustics requirements. Thanks to new eco-design standards, both the OEM and suppliers can increase and improve eco-friendly aspects such as recycling end of life vehicles. The use of end of life materials in a new car includes: automotive shredded residue (ASR) such as tire fibers included in damping materials, chips foam from seats for acoustical shields, and automotive shredded residue for acoustical dash insulators."
SEA Modeling of Vehicle Wind Noise and Load Case Representation,"Vehicle wind noise is becoming increasingly important to customer satisfaction. Early wind noise assessment is critical to get things right during the early design phase. In this paper, SEA modeling technique is used to predict vehicle interior noise caused by the exterior turbulence. Measured surface turbulence pressures over vehicle greenhouse panels are applied as wind noise load. SEA representation of wind noise load case is investigated. It has been found that current SEA wind noise load case over-estimates at frequencies below window glass coincident frequency. A new concept of noise source pole index is introduced and a new wind noise load coupling has been developed. Comparison with vehicle wind tunnel measurements shows that the proposed load case significantly improved prediction accuracy."
Experimental Characterization of the Unsteady Flow Field behind Two outside Rear View Mirrors,"The unsteady flow fields behind two different automobile outside side rear view mirrors were examined experimentally in order to obtain a comprehensive data base for the validation of the ongoing computational investigation effort to predict the aero-acoustic noise due to the outside rear view mirrors. This study is part of a larger scheme to predict the aero-acoustic noise due to various external components in vehicles. To aid with the characterization of this complex flow field, mean and unsteady surface pressure measurements were undertaken in the wake of two mirror models. Velocity measurements with particle image velocimetry were also conducted to develop the mean velocity field of the wake. Two full-scale mirror models with distinctive geometrical features were investigated."
Sound Quality of Exhaust Pipes Through Semi-Active Noise Control,"Due to the increasing demands on NVH levels Sound Quality has become a major issue for the vehicle development. This includes the care taken with the internal noise levels as well as with the way noise is perceived. A different issue relates to the sensation the vehicle leaves through the type of noise coming from the engine to the car exterior. A major part of this sensation comes from the exhaust system through the mufflers which also contribute to the interior noise to some extent. In situations involving one-dimensional wave propagation as in engine exhaust systems, the use of active noise control is a strategy with increasing interest. Nevertheless, considerable restrictions due to the actuators and to the computational power needed for an active control system reduce the possible practical applications. The design and implementation of a semi-active noise control system for ducts based on Helmholtz resonators are presented in this work, in order to overcome these shortcuts. The engine speed, related to predominant frequency components of the noise, is used as reference for an active tuning of the passive, dynamical characteristics of a Helmholtz resonator by varying parameters like resonator volume through a computer controlled mechanism. The practical implementation of the system and an experimental setup are discussed together with the necessary procedures for the system."
Tackling NVH ONE dB PER DAY,"New tools and technologies are helping engineers reduce vehicle Noise, Vibration and Harshness. The vehicle chief engineer did not like what he was hearing on this recent evaluation ride. He was reviewing a new transmission scheduled for production in his company's iconic sporty car. But the marriage of transmission and platform was generating unacceptably high cabin-noise levels. The CE wasn't pleased. His design and manufacturing engineers explained that the new gearbox featured a thin-wall aluminum case for reduced mass. However, the lightweight case was the noise transmitter."
Foam for NVH solutions,New innovations for a wide variety of sound-deadening applications.
Nissan targets cabin NVH with big investment in Sentra upgrade,"Significant updates to the seventh generation Sentra make the 2016 model Nissan's quietest and most dynamic-driving compact sedan to date. The automaker invested more than three times its typical outlay for a mid-cycle refresh on Sentra, according to Chris Schwerkoske, senior product planner. The 2016 model contains more than 550 new parts involving the exterior, interior, suspension, and steering systems, Schwerkoske told Automotive Engineering."
Armored Response Vehicle for Bomb Disposal Teams,"Lenco Industries Pittsfield, MA 413-443-7359"
Analysis and Optimization of a Window Latch Effort Problem,A mathematical model was first developed for the opening effort analysis of vehicle side window latch. The model was then linked to an optimization program to perform optimization studies. The optimization parameters are the coordinates of key joints and the shifts of contact surface profile. Both deterministic and random optimization problems were formulated and solved. Results of the optimization studies were compared and conclusions were drawn from the results.
Cabin Interior Noise Acoustic Assessment under the Influence of Air Intake System: Simulation and Experimental Investigation,"This paper presents an assessment of the cabin interior noise under the influence of the AIS (Air Intake System). The AIS is one of the four main noise sources present in the vehicle and is therefore necessary to evaluate its contribution and thus improve its noise emission levels. It is also important to achieve the acoustics targets during the development phase, as noise and vibration are still amongst the main causes for problems at the last design and even pre-release stages. In order to assess the vibroacoustic behaviour and reduce the extent of the virtual prototype phase, durability and acoustic models was integrated. Using these models, stress and fatigue were checked. Modal and structural analyses were performed, orifice noise and radiated noise evaluated. Also SPL (Sound Pressure Level) was computed at the driver and passenger's ear location. Fluid/structure interaction analyses verify the AIS and cabin coupled response effects in the interior noise. Following that, simulation and experimental measurements were compared. The comparison shows the AIS structural frequencies that have significant contribution to the interior sound pressure level. These analyses also show the advantages of the integration between durability and acoustic numerical models, reducing cost and time during the project virtual phase. From now this paper gives a brief description on how to perform cabin interior noise analyses under the influence of AIS."
On Simulating Passenger Car Side Window Buffeting,"Side window buffeting is simulated for a passenger car using unstructured mesh and a finite volume based CFD solver. We first provide a description of the analysis method. Two vehicle configurations are considered: front window open and rear window open. The accuracy of RNG k-ε and LES turbulence models is evaluated for this application by comparing predicted buffeting frequency spectrum with corresponding experimental measurements made in a wind tunnel. Further, the effects of several parameters on buffeting frequency and amplitude are studied. They include vehicle speed, yaw angle, inlet turbulent intensity, observer location inside the passenger compartment, presence of exhauster and side view mirror design. Simulation results prove to follow the trends observed in the experiments."
Experimental Verification of Residual Compression in Tempered Automotive Glass with Holes,"Tempered float glass is commonly used for both side windows and backlites in the automotive industry. The success of such products is primarily attributed to high level of residual compression, following tempering, which provides abrasion resistance as well as 3X higher functional strength to sustain mechanical, vibrational and thermal stresses during the vehicle's lifetime. Certain applications of tempered glass, however, require mounting holes whose surface-finish must be controlled carefully to withstand transient tensile stresses during tempering. Simultaneously, the nature and magnitude of residual compression at the hole must provide sufficient robustness to bear mounting, vibrational and thermal stresses throughout the life of the vehicle. This paper presents (i) analysis of residual compression at the hole, (ii) measurement of biaxial strength of annealed glass with hole at center, and (iii) measurement of biaxial strength of tempered glass with hole at center. Both fractographic analysis and the biaxial strength data of annealed and tempered glasses are used to deduce the magnitude of residual compression at the hole. These data show excellent agreement between analytical solution for residual compression and that inferred from biaxial strength. The nature of residual stresses at the hole, which differs considerably from that of classical tempering, is highlighted."
Influence of Cabin Modal Density on Vehicle Interior Noise,The increasing trends towards smaller power units running at high speeds together with the increasing use of diesel engines in passenger vehicles have resulted in higher vehicle interior noise and vibration levels. The customer awareness towards comfort of vehicle specifically with reference to perceived noise levels has become a selling point for vehicle manufacturers. In this paper experimental and analytical techniques used to study the influence of cabin related parameters on interior noise are presented. These techniques were applied to study interior noise of truck cabins. The noise and vibration signals were measured at body panels and at Operators Ear Location (OEL) for different engine speeds. The natural frequencies of body panels were identified by using frequency response function measurements. The modal analysis of acoustic cavity was carried out using finite element technique.
New Cockpit Human-Machine-Interface Concept,"More and more features in today's vehicles put increasing demands on the driver's ability to process information, operate functions and simultaneously concentrate on driving. This necessitates simplifying and optimizing the human-machine-interface (HMI). Therefore, Siemens VDO has developed a cockpit study, “Breeze”, showing a new, ergonomic HMI concept in an attractive design. The number of switches is minimized by implementing a force feedback switch, allowing intuitive operation of several functions via a menu system displayed on a 10 inch monitor. Specific driver functions are operated by mulit-function keys in the steering wheel with a secondary display. The turn indicator is operated by squeezing the steering wheel grips. Vibration elements are activated in dangerous situations to alert the driver. Additional features include flat panel loudspeakers and instrumentation with 3D-effect Many technical details are presently under development, however, some solutions are already in production."
Reduction of Road Noise by the Investigation of Contributions of Vehicle Components,"The mobility technique is used to analyze the transfer functions of road noise between the suspension and the body structure. In the previous analyses, the suspension system and the body structure are altogether modeled as subsystems in the noise transfer path. In this paper, the mobility between the suspension and the body structure is analyzed by the dynamic stiffness at the connecting points. The measured drive point acceleration FRF at the connecting point in the transfer path was used to estimate the contributions of subsystems. The vibration modes of tire, the acoustic noise of tire's interior cavity, the vibration modes of the car's interior room, and the vibrations of body structure and the chassis are also considered to analyze the coupling effects of the road noise. Analyzing the measured results, direction for modification of car components is suggested. The road noise around 250Hz in car's interior room is reduced by the modifications of the housing panel near the rear suspension."
An Analysis of Idling Vibration for a Frame Structured Vehicle,A finite element model for an entire frame-structured sports utility vehicle was made to evaluate the characteristics of the idling vibrations for the vehicle. The engine exciting forces were determined by Souma's method to simulate the idling vibrations. The modeling of the power plant and the entire vehicle was verified by the reasonable agreement of the experiment and calculation results. Attention was focused on the frequency of the first-order vertical bending mode for the frame. It has become clear that the idling vibration level of the vehicle is lowered by decreasing the frequency of the first-order frame bending mode.
Micro Step vs. Full Step - A Quantitative Competition,"Stepper motors are used in a wide range of automotive applications. High reliability at low cost, low power dissipation, and low noise are the main requirements for those applications. Compared to full stepping, micro stepping has better performance concerning reliability, accuracy, low-noise, and also on wear out. With micro stepping, a low resolution low cost stepper motor may have the same or better performance then a more expensive stepper motor with higher resolution with full stepping. To decide either to realize micro stepping or full stepping, quantitative criteria are required for the competition. This article gives those criteria based on the physics of the stepper motor."
Evaluation of Aerodynamic Noise Generated in Production Vehicle Using Experiment and Numerical Simulation,"Aerodynamic noise generated in production vehicle has been evaluated using experiment and numerical simulation. Finite difference method (FDM) and finite element method (FEM) are applied to analyze the flow field, and Lighthill's analogy is employed to conduct acoustic analysis. The flow fields around front-pillar obtained by numerical simulations agree with those by experiment for two cases with different front-pillar shape. Moreover, the distribution of acoustic source predicted by FEM is consistent with that obtained by experiment. Present study ascertained the feasibility and applicability of FEM with SGS model towards prediction of aerodynamic noise generated in production vehicle."
Development of a Luxury Vehicle Acoustic Package using SEA Full Vehicle Model,"Interior noise has become a significant performance attribute in modern passenger vehicles and this is extremely important in the luxury market segment where a quiet interior is the price of entry. With the elimination of early prototype vehicles to reduce development costs, high frequency analytical SEA models are used to design the vehicle sound package to meet targets for interior noise quality. This function is important before representative NVH prototypes are available, and later to support parameter variation investigations that would be cost prohibitive in a hardware test. This paper presents the application of an analytical full vehicle SEA model for the development of the acoustic package of a cross over luxury utility vehicle. The development concerns addressed were airborne powertrain noise and road noise. Power flow analysis was used to identify the major noise paths to the interior of the vehicle. The SEA model allowed the performance of alternative designs to be assessed, the reduction of the power input from the major noise paths to be quantified and optimization of the acoustic package for both road noise and powertrain noise to be completed. The SEA model was used to drive acoustic package design to meet not only acoustic targets but also the mass and costs targets and deliver an optimized package. The other major benefit of the full vehicle model that this paper will present are the impacts of not meeting sub-system requirements that are usually rolled down to the supplier. This is invaluable as it informs the vehicle design team what the impact is on the sound pressure level at the “drivers ear” of not meeting subsystem requirements, for example the “engine compartment absorption or front of dash transmission loss requirement”. It is concluded that the use of a detailed SEA model is a highly valuable design tool to support ‘A’ to ‘B’ design and material comparisons, to identify major noise paths, and to provide direction to the program."
Power Steering Pump Sound Quality and Vibration - Test Stand Development,"The quietness of the interior of automobiles is perceived by consumers as a measure of quality and luxury. Great strides have been achieved in isolating interiors from noise sources. As noise is reduced, in particular wind and power train noise, other noise sources become evident. Noise reduction efforts are now focused on components like power steering pumps. To understand the contribution of power steering pumps a world-class noise and vibration test stand was developed. This paper describes the development of the test stand as well as it's objective to understand and improve the sound quality of power steering pumps."
"Squeak and Rattle Behavior of Elastomers and Plastics: Effect of Normal Load, Sliding Velocity, and Environment","The use of plastics and elastomers, for interior and exterior automotive components, presents a risk of frictionally incompatible materials contacting each other, resulting in squeaks, ticks, chirps… Ford's NVH S&R Department, and MB Dynamics have developed a tester (Figures 1 and 2) that can measure friction, and sound, as a function of sliding velocity, normal load, surface roughness, and environmental factors that allows us to provide up-stream engineering information to Forward Model Design Engineers. When material pairs undergo sliding contact, friction forces can cause elastic deformation adjacent to the contacting surfaces. The elastic deformation is a mechanism for storing energy and sound is produced when the energy is released. The sound that we hear may be a squeak or squeal (multiple stick-slip) or a tick (single stick-slip). However if the sliding material composition (e.g. coatings, low friction additives…) and the structure (surface roughness or stiffness/compliance) of the sliding components is properly selected, we can avoid or minimize noise by minimizing elastic deformation and therefore the release of stored elastic energy. The release of the stored elastic energy can occur when the kinetic friction is less than the static friction. This difference can be duplicated during single excursion events or when undergoing sine or random vibration. In the case of thermoplastics, cold temperatures can have a major influence on acoustic properties by reducing chain mobility (Tg) at the sliding contact surface leading to an increase in the surface contact stiffness and therefore changing the elastic deformation properties."
Wind Noise and Drag Optimization Test Method for Sail-Mounted Exterior Mirrors,"An L18 Taguchi-style Design of Experiments (DOE) with eight factors was used to optimize exterior mirrors for wind noise and drag. Eighteen mirror properties were constructed and tested on a full size greenhouse buck at the Lockheed low-speed wind tunnel in Marietta, GA. Buck interior sound data and drag measurements were taken at 80 MPH wind speed (0° yaw angle). Key wind noise parameters were the fore/aft length of mirror housing and the plan view angle of the mirror housing's inboard surface. Key drag parameters were the fore/aft length of the mirror housing, the cross-section shape of the mirror pedestal, and the angle of the pedestal (relative to the wind)."
Identification of Annoying Noises in Vehicles,"During its initial use the vehicles go through a period of adjustment, in which the structure and moving parts show their problems of looseness, tightness, stress, excess or lack of torque by emitting characteristic noises of different intensity and frequency. These noises are bothersome for the user. Car manufactures and private companies have specially-trained personnel who are able to identify the source of those noises simply by listening to them. Once the source is identified, the problem is often solved by tightening the moving parts and/or using polymer materials. For the companies that provide the service of elimination of annoying noises inside the cabin, however, this dependence on such specially trained people is a problem. As an alternative, there is a proposal to develop a system that measures the noise patterns inside the cabin during dynamic tests, subtracts the engine noise, identifies the annoying noise, obtains the frequency spectra of the detected noise by using the Fourier and Hilbert transforms, compares these spectra with the spectra of the most frequently annoying noises found inside cabins of vehicles and, finally, reports the potential sources of the annoying noise detected. This paper describes the system assembled for this purpose and its performance in the elimination of annoying noises inside vehicle cabins."
A Case Study on Airborne Road Noise Reduction of a Passenger Vehicle,"This paper presents a case study on reducing road noise of a passenger vehicle. SEA, insertion loss and sound intensity measurements were the tools used in the study. A SEA model was constructed to predict the primary paths (panels or area) contributing to the overall interior sound field. Insertion loss measurements were used to verify the primary contributing paths identified using SEA. To provide further details of the primary paths, intensity maps of identified panels were measured allowing detailed reconstruction of the contributory panels. The SEA model, insertion loss, and intensity maps aided in providing possible design fixes that will effectively reduce road noise. Finally, comparisons of predicted results versus actual results at both a subsystem and a full vehicle level are included in this paper."
The Rattle Trap,"This paper addresses the fundamental mechanisms associated with Buzz, Squeak and Rattle (BSR) sounds and the analysis of their acoustic signatures. These sounds will be generated and analyzed individually with a conventional popular metric in the presence of typical background sound. Baseline computations of the background will be performed for comparison. This paper will present a look at the sensitivity of the current popular metrics ability to identify BSR specific sounds in the presence of background noise levels. This understanding of the measurement and quantification of the specific BSR sound signatures can be the basis for design target setting with respect to specific BSR phenomena. As well, this can lead to a better understanding of whether or not it is appropriate to quantify these phenomena together or if there is a need for a “Rattle Trap” metric, a “Buzz Trap” metric or a “Squeak Trap” metric."
Vehicle Panel Vibro-Acoustic Behavior and Damping,"Damping treatments are widely used in passenger vehicles, but the knowledge of damping treatments is often fragmentary in the industry. In this study, vibro-acoustics behavior of a set of vehicle floor and dash panels with various types of damping treatments was investigated. Sound transmission loss, sound radiation efficiency as well as damping loss factor were measured. The damping treatments ranged from laminated steel construction (thin viscoelastic layer) and doubler plate construction (thick viscoelastic layer) to less structural “bake-on” damping and self-adhesive aluminum foil-backed damping treatments. In addition, the bare vehicle panels were tested as a baseline and the fully carpeted floor panel was tested as a reference. The test data were then examined together with analytical modeling of some of the test configurations. As expected, the study found that damping treatments add more than damping. They also add mass and change body panel stiffness. Each of the three factors affects different aspects of noise and vibration of vehicle panels."
Motorhome Acoustical Issues: An Overview,"Motorhomes or recreational vehicles (RV's) are unique vehicles in that they pose many interesting design challenges to acoustical engineers. This type of vehicle has many of the typical NVH (Noise Vibration and Harshness) issues seen in passenger cars and heavy trucks; however, there is an entire arena of NVH issues that are not seen in these other products. The issues are not present in these other markets; because a motorhome, not only serves as a means of transportation, it also serves in a secondary role as a home. The dual role of the coach creates many residential noise concerns. Some of these issues include managing generator sound levels while the coach is either parked in a campsite or on road, controlling engine noise levels for designs where the bed serves as the engine cover, and controlling wind noise to improve speech communication between the driver and passengers. Complicating these issues is the fact that each unit is semi-customized. In many cases the owner also has a choice of chassis, generator, engine and drivetrain along with appliances and other amenities that affect the acoustics. With the high cost of these vehicles, owners demand low noise levels and high sound quality in all aspects of vehicle operation. This paper presents an overview of numerous Class A motorhome sound quality studies and presents typical sound levels and techniques for controlling undesirable sounds."
A Comparison of Seven Different Noise Identification Techniques,"Today's NVH engineers have at their fingertips a myriad of different noise source identification techniques available with which to locate noises. Unfortunately, with so many different techniques available, it is not always clear which technique is the best for a specific application. Should one use Sound Intensity? Or is Acoustic Holography a better tool? But if there are noises above 5kHz, which technique works then? And what is Beamforming? Would that work? With so many choices, it is required to know before the test which technique is the best choice. This paper will give an overview of 7 popular techniques to help the practicing NVH engineer decide which technique is the best for a specific application. A practical explanation along with a real life example will be given to help make clear where and how a technique can be used."
Windshields With New PVB Interlayer for Vehicle Interior Noise Reduction and Sound Quality Improvement,"Noise transmission through automotive windshields is the subject of extensive laboratory acoustic and full scale high-speed track NVH evaluation. Standard windshields transmit structure-borne noise through resonances at low frequencies, and wind noise and airborne noise due to coincident effect at high frequencies. Approaches to enhance windshields NVH performance and to improve vehicle interior noise quality are explored. The study shows that the most effective approach is to design a new interlayer for windshields. This leads to the development of an acoustic grade PVB interlayer. To quantify the noise reduction by windshields with the new PVB interlayer, Solutia commissioned NVH testing of the windshields installed on cars, comparing these with factory-equipped standard windshields. Dynamic responses of the windshields were studied in laboratory on a dynamometer and resulting frequency response functions measured. A considerably high damping of resonant vibrations and significant reduction of structure-borne noise were noted. Further studies on the windshields for enhanced noise reduction, in particular wind and road noise, were conducted with several vehicles on high-speed test tracks. Test results show that the use of the windshields with new PVB interlayer results in 2 - 6 dB reduction in the cabin noise in high frequency range and up to 2 - 3 dB reduction in low to mid frequency range. Both subjective and objective results indicate that these windshields can greatly improve the vehicle wind noise and road noise performance and noise quality within the cabin, and result in the quieter passenger compartment."
Exhaust System Robustness Analysis Due to Flex Decoupler Stiffness Variation,"The function of flex decoupler is to reduce the vibration transferred from the engine to the vehicle body. The stiffness of the flex decoupler is a key parameter in the vibration control. This paper deals with decoupling exhaust hot end and cold end to minimize vibration transfer. A computer aided engineering (CAE) based design of experiment (DOE) is used to investigate the coupling stiffness. A finite element model is built to analyze the exhaust vibration responses. Robustness of the exhaust system is analyzed. The analysis reveals that vertical stiffness of the flex decoupler is the key parameter for the hanger force response. The main control factors for exhaust vertical and lateral bending frequencies are vertical and lateral stiffnesses of the decoupler, respectively."
Light-Weight Localized Structural Reinforcements for Structural and NVH Applications,"The use of adhesively bonded localized reinforcements is a relatively new concept in the automotive industry. Although use of this reinforcement method is in its early stages, these reinforcements are now used for a variety of applications in the automotive industry including crash worthiness, fatigue resistance, and NVH. This approach can provide relatively fast, easy, non-intrusive, and cost effective solutions for OEM's when compared to traditional reinforcement methods. Also overall weight can be simultaneously reduced since the reinforcement is placed only where it is needed instead of filling an entire section with foam or changing the metal thickness along an entire body member. Materials and concepts have been developed that can be used to improve the structural stiffness and the resulting NVH performance of the vehicle. This paper will discuss the use of localized reinforcements including materials, applications, and potential uses and the benefits."
Improved Acoustics Through Perforated Plastic Panels,"In an effort to further reduce noise inside the passenger compartment of automobiles, a new approach has been made to incorporate parts not traditionally considered to be acoustic in nature. Through use of patented technology, the acoustic improvement can even be tuned to specific audible ranges to quiet background noise and improve audio clarity for devices such as hands free cellular phone devices. This paper will discuss the theory of using perforations for acoustic applications, demonstrate how the acoustic response can be tuned with flat sample development and illustrate actual invehicle data showing potential improvement of perforated plastic components."
Portable NVH Dynamometers,"Noise Vibration and Harshness (NVH) characteristics have become a key differentiator between “Good” vehicles and “Best-In-Class” vehicles. While all OEM's and most Tier 1 suppliers have on-site in-ground chassis dynamometers, a need was identified to design, develop and bring to market, a fully capable portable NVH full vehicle chassis system. The original concept entailed a device, which could be brought to the customer's location, be fully self contained, requiring no external power, and provide data acquisition using transducers that would not contact the vehicle. With traditional instrumentation taking several hours to install, non-contacting lasers would be used to provide significant timesaving, and prevent any possible damage to the vehicle from pinched wires. The new methodology should provide data acquisition in as little as 20 minutes. Analysis would be accomplished immediately following testing, with hard copies available before the next vehicle was ready to run. Full vehicle NVH root cause analysis, including system balancing would be done in minutes, at the customer's location, assembly plant, engineering center, or Visteon site. Along with the NVH capabilities, performance data would also be available including horsepower, fuel testing, etc. This paper presents history, design, development, implementation, use, and future developments for the Visteon Portable NVH/Performance Dynamometers that are now in service. Showcasing how the portable dynamometers support a vehicle level NVH design methodology is presented, which seeks an optimum balance of system design criteria. This is possible by providing bumper-to-bumper NVH root cause analysis, driveline imbalance sensitivity to first order forces, driveline imbalance cross-talk analysis, wheel/tire imbalance and force variation sensitivity, system resonance identification, and dynamic mount transmissibility analysis."
Acoustic Sources localization: Application to Wiper Aerodynamic Noises,"The reduction of aerodynamic noise sources is today an important topic in automotive industry. In order to localize the different sources on the arm and blade, a 48 microphones acoustic antenna coupled with a software based on the beam-forming imaging method has been used. Obtained results are validated inside the car on track. Aerodynamic numerical simulations are compared to aerodynamic measurements. The turbulent kinetic energy distribution obtained from the simulations is then compared with measured sound sources localization maps: the results are presented and commented for two wiper configurations."
Vehicle Retention Methods for Four-Wheel Chassis Dynamometer Testing,"Four-Wheel Anechoic Chassis dynamometers are an established and valuable tool used extensively in the development of noise control systems for the automotive industry. Variations in vehicle platforms, exterior styling, as well as, increases in vehicle test load condition ranges have changed the methods required to secure vehicles to chassis dynamometers. This paper will investigate two methods used to retain vehicles for four-wheel chassis dynamometer testing. These methods affect the acoustic signature of the test vehicle and can influence the measured performance of acoustic treatments. The performance of a typical acoustic interior system will be measured and analyzed under different vehicle retention methods as well as the influence of retention force variation. Best practice recommendations are then discussed."
Collision Performance of Automotive Door Systems,"Historically, most safety related improvements to door systems have involved retention of occupants within the vehicle. However, such improvements have not been without some safety trade-offs. The recent update to FMVSS 214 (Side Impact Protection) has focused attention on increased occupant protection in side impacts. The standard essentially increases vehicle side strength requirements in order to reduce intrusion into the occupant space. The safety consequences associated with strengthening vehicle side structure will be evaluated with respect to various impact configurations. Energy management considerations of current as well as conceptual door systems during a collision will also be discussed. Individual latch and hinge component testing as currently required by FMVSS 206 does not completely evaluate the collision performance of the door as a system. From field collision evaluation, it has been seen that doors and surrounding side structure must act as a system to efficiently manage collision forces and distribute occupant loads. Procedures for evaluating current and future door systems by means of revised laboratory testing procedures will be evaluated."
Application of Experimental Design in the Steady State Particulate Exposure Levels in a 1992 International School Bus,"A steady state mobile test was developed to measure the concentration of breathable particles that can enter the cabin of a school bus. The principles of experimental design were used to identify the experimental conditions for the test and to analyze the data. The design consisted of a series of steady-state tests using a 1992 International school bus. The testing was performed on a closed three mile track at the Army Test Center in Aberdeen, MD. The mass concentrations of particles smaller than 2.5 microns were measured at three locations inside the bus and at the air intake into the engine. The number concentration of particles was measured at the tailpipe. Three factors were varied at three levels in a Box-Benhken design. The steady state speed was set at 5, 30, and 55 mph. A load was applied to the engine with a mobile dynamometer to simulate a 0, 0.67% and 1.33% road grade. Tests were performed with three window configurations: all windows open, all windows closed, and all windows half open. Steady state averages for PM2.5 mass concentrations inside the bus ranged from 2.2 μg/m3 to 111 mg/m3. An analysis of variance indicates that there was a significant difference in the concentration of particles inside the bus as a result of the varying speed and windows conditions. At the 95% confidence interval the factors of speed and windows had a significant effect on the particle mass concentration. Furthermore, the effect of speed on the particle concentration was dependent on the window configuration used."
An Efficient Light Weight all Plastic Dual Rack and Pinion Window Lift Mechanism for Automotive Vehicles,"In the latter half of 2004, a new concept of window lift mechanism will be supplied to a major OEM for a high volume passenger car in the North American market. This new concept of window lift mechanism, marketed by Dura Automotive Systems, Inc. as the Racklift™, was jointly developed in conjunction with an independent inventor. The Rack Lift mechanism is essentially an all-plastic construction, which results in a very light weight unit. Plastic gears are driven along each side of an injection molded unitary dual rack providing a quiet and efficient operation. The higher efficiency of this mechanism, compared to traditional designs, allows use of smaller, lighter and lower output electric motors. The plastic mechanism is greaseless and thus produces a constant efficiency over the required operating temperature range. The combination of high efficiency, lightweight and robustness to temperature makes this an ideal concept for automotive applications."
Comparison of Indoor Vehicle Thermal Soak Tests to Outdoor Tests,"Researchers at the National Renewable Energy Laboratory conducted outdoor vehicle thermal soak tests in Golden, Colorado, in September 2002. The same environmental conditions and vehicle were then tested indoors in two DaimlerChrysler test cells, one with metal halide lamps and one with infrared lamps. Results show that the vehicle's shaded interior temperatures correlated well with the outdoor data, while temperatures in the direct sun did not. The large lamp array situated over the vehicle caused the roof to be significantly hotter indoors. Yet, inside the vehicle, the instrument panel was cooler due to the geometry of the lamp array and the spectral difference between the lamps and sun. Results indicate that solar lamps effectively heat the cabin interior in indoor vehicle soak tests for climate control evaluation and SCO3 emissions tests. However, such lamps do not effectively assess vehicle skin temperatures and glazing temperatures."
On The Causes of Image Blurring in External Rear View Mirrors,"Effective rear view vision from external mirrors is compromised at high speed due to rotational vibration of the mirror glass. Possible causes of the mirror vibration are reviewed, including road inputs from the vehicle body and a variety of aerodynamic inputs. The latter included vibrations of the entire vehicle body, vibrations of the mirror “shell”, the turbulent flow field due to the A-pillar vortex (and to a lesser extent the approach flow) and base pressure fluctuations. Experiments are described that attempt to understand the relative influence of the causes of vibration, including road and tunnel tests with mirrors instrumented with micro accelerometers. At low frequencies, road inputs predominate, but some occur at such low frequencies that the human eye can track the moving image. At frequencies above about 20Hz the results indicate that at high speeds aerodynamics play a dominant role. When the vehicle is yawed, significantly greater aerodynamic inputs arise from the leeside vortex than from the vortex on the upwind side. However since the mounting of the mirror glass is part of a complex dynamic system the results are configuration specific."
LIN Protocol -Technology Review and Demonstration in Power Window Application,"This paper describes and investigates the possibilities and the advantages of using LIN as a multiplexed electrical system in a vehicle. LIN is a communication protocol designed for controlling simpler electrical components in a vehicle, like for example switches, sensors and actuators. Investigations have been done concerning the technique behind LIN as well as the recourses needed in order to implement LIN-communication between components on the power window of a Maruti Suzuki's ZEN car. Clearly the benefits of using LIN are low cost to feature ratio and at the same time reducing harness costs and enabling higher reliability of the vehicle functions."
“Clear Vision” Automatic Windshield Defogging System,The present paper describes the system design for the Clear Vision auto defog system and the improvements made to the Integrated Dew Point and Glass Temperature (IDGT) sensor. The Clear Vision auto defog system has been implemented on a 2000 Cadillac DeVille. Preliminary validation tests demonstrate satisfactory performance.
New Procedure for Noise Source Mapping During Pass-By Noise Measurements,"Acoustic source identification is an important issue in both early and prototype validation stages of NVH design. OEMs and suppliers need to assess the entire description of vehicle noise emission, to understand and address interior comfort and exterior radiation issues. Today, none of the existing methods allow engineers to get a quick snapshot of sources contributing to the external pressure level affecting pass-by noise emission compliance, requiring long and arduous testing projects with & without physically masked components. A new acoustic imaging technique provides an important solution. The method is based on a microphone array. Like a camera, but unlike current holographic methods, the software delivers focused, near-realtime 2D colour snapshots and movies, corresponding to the sound pressure level at the region of interest. Typically, the entire side of a vehicle can be analysed during one pass-by run. Examples are given to demonstrate the time-space or frequency-space resolution of mappings, using one data set for numerous configuration analyses in a very short time. The technique is also being used successfully for trains, aircraft, trucks, tractors, and other vehicles for optimising exterior sound radiation characteristics"
Nonlinear Model Validation for Automotive Seat Cushion-Human Body Combined Structure,"In this paper, a nonlinear dynamic model for automotive cushion-human body combined structure is developed based on a nonlinear seat cushion model and a linear ISO human body model. Automotive seat cushions have shown to exhibit nonlinear characteristics. The nonlinear seat cushion model includes nonlinear stiffness and nonlinear damping terms. This model is verified by a series of tests conducted on sports car and luxury car seats. The transfer functions from the tests for human body sitting on an automotive seat changes with the vibration platform input magnitudes. This indicates that the combined structure possesses nonlinear characteristics. The nonlinear model is validated by the transfer functions from the test. The paper discusses the influence of the parameters of the nonlinear structure on the design of seat and assessment of human body comfort."
"Automotive Buzz, Squeak and Rattle (BSR) Detection and Prevention","Recent advances in automotive noise control engineering have reduced the general level of noise in the passenger car compartment and focused more attention on irritating noises. Buzz, Squeak and Rattle (BSR) have surfaced as major concerns. Customers increasingly perceive squeak and rattle as direct indicator of vehicle build quality and durability as revealed from the J. D. Power surveys. The high profile nature of squeak and rattle has motivated the manufacturers to pay attention during early phase of vehicle development program. Traditional methods of prevention and elimination of squeak and rattle have been found to be no longer sufficient to develop acceptable products in shortened product development cycle. Basic causes, design guidelines and validation technique using laboratory simulation and digital data acquisition have been successfully developed to push the BSR prevention process upstream in the development cycle. A test procedure to map the vehicle BSR performance with the use of laboratory simulation and digital data acquisition tools has been developed. The vehicle BSR performance is evaluated based on the subjective rating system. As commitment towards customer to meet his expectations in quality right from purchase till the useful life of vehicle, the vehicle BSR performance is monitored till the end of life. Lab simulation technique allow determination of sub-system or prototype vehicle degradation much early in the development process. Simulation is used to map the progression of noise with respect to vehicle life and usage conditions. Targeting at reducing noises after durability exposure, effectively later in the vehicle life, is crucial in ensuring new vehicle quality."
Vehicle Interior Noise Source Identification and Analysis for Benchmarking,"The acceptance criterion of any vehicle in terms of user comfort invariably depends on the vehicle interior noise and vibration characteristics. The levels of sound energy and structural excitation inside the vehicle compartment measures the amount of annoyance in terms of quality and comfort. For vehicle interior noise abatement and noise treatment, it is desirable to quantify the noise sources by determining the sound power contribution from each vehicle component/panel, acoustic leakages inside the vehicle, body panel vibrations, gearshift lever and steering wheel vibrations. Many a times, it is necessary to arrive at benchmarks or targets for the various sources of noise in order to refine the systems. The present paper describes a methodology for interior noise source identification and its analysis for benchmarking. Two different vehicles of the same class but of different makes were compared and evaluated for interior noise and vibration levels. Intensity mapping of the complete interior of both the vehicles was carried out and compared. Similarly, the vibration and sound pressure levels were measured and compared at selected locations and at anti-node points. The effectiveness of the firewall, silencers and engine mounts were also checked and compared. The sound intensity measurements at stationary condition with different engine speeds inside the vehicle helped in computing the sound power from different vehicle panels, and identifying sources and their contribution. The correlation between pressure and vibration levels of different sources with acoustical and structural transfer paths were studied. The modal behaviour of the acoustic cavity and the structural panels were studied using finite and boundary element techniques, to predict the sound pressure levels at selected locations and the contribution of different vehicle panels. This provided benchmarking - sourcewise, acoustic as well as structural and system noise-engine, firewall, different panels, silencers, etc. enabling to set individual system targets."
Vibration Testing and Modal Analysis of Airplanes – Recent Advances,"The paper will introduce some recent advances in vibration testing and modal analysis of airplanes. Recently, a very promising parameter estimation method became available, that has the potential to become the new standard. The main advantage of this so-called PolyMAX method is that it yields extremely clear stabilization diagrams even for broadband and high-order analyses. The method will be applied to two aircraft cases: a Ground Vibration Test using broadband shaker excitation on a small composite aircraft and in-flight data using natural turbulences as excitation. These two data sets allow illustrating both the classical Frequency Response Function based as well as the operational output-only modal analysis process."
Dynamic Modal Analysis and Optimization of a Mechanical Sensor Arm Deployment System for a C-130 Aircraft,"During structural engineering design two of the most overlooked design facets of a finished product is understanding the behavior characteristics of how the product will react when resonated at its natural frequencies and actually defining and understanding the overall vibration profile responsible for the excitation of the structure. A C-130 mechanical arm/pod system has been developed to accommodate 1,000-pounds of sensor payload deployable in flight from a C-130 Hercules military aircraft (variants B thru J). The mechanical arm/pod system will be subjected to a profile of vibration from numerous sources during deployment and while in the final operating position. A general vibration profile for the mechanical arm/pod will be compiled from the plane’s four T-56-A-15 turboprop engines, the atmospheric turbulence and random gust loads. A pitot-accelerometer sensor probe was used to obtain vibration data of the C-130 ramp during a zero-light turbulence category flight for indicated airspeeds of 130 knots and 150 knots. The mid/low frequency values with worse case scenario magnitudes induced by buffeting, flutter and gust loads were computed. A formal vibration analysis was conducted utilizing the Finite Element Approach and Modal Analysis using Pro/ENGINEER and Pro/MECHANICA software packages. The natural frequency modes for the mechanical arm/pod system was computed in the x, y and z directions with three different geometrical configurations of the structural cross-member supports."
Vibro-Acoustic Modeling of Aircrafts Using Statistical Energy Analysis,"The Statistical Energy Analysis – SEA is one of the main methods used to study the vibro-acoustic behavior of systems in the aeronautic, automotive and naval industries. The principal advantages of this method are the possibility of analysis in the mid and high frequencies range, the reduced computational costs when compared with other methods (like Finite Element Method or Boundary Element Method) and ease modeling of different sources of noise and vibration. As a statistical method, SEA provides results associated with average values in time, space and in an ensemble of similar structures. In aerospace applications, where the noise and vibration sources are usually random, SEA is particularly indicated. SEA also allows the straightforward modeling of the noise control treatments used in commercial aircraft and the further optimization of these treatments, reducing weight and costs. In this work, the steps followed at the development of an EMBRAER aircraft SEA model are presented. The hypotheses adopted during the subsystems definitions are discussed. The noise and vibration sources considered at the model are described and the calculations of the power inputs are demonstrated. Finally, some results obtained through the model are shown and some possibilities of analysis using the model are explored."
Analytical Design of Cockpit Modules for Safety and Comfort,"This paper reviews the state of the art on analytical design of cockpit modules in two most crucial performance categories: safety and comfort. On safety, applications of finite element analysis (FEA) for achieving robust designs that meet FMVSS 201, 208 and 214 requirements and score top frontal and side NCAP star-ratings are presented. On comfort, focus is placed on Noise, Vibration and Harshness (NVH) performance. Cutting-edge analytical tools for Buzz, Squeak and Rattle (BSR) avoidance and passenger compartment noise reduction are demonstrated. Most of the analytical results shown in this paper are based on the development work of a real-life application program. Correlations between the analytical results and physical test results are included. Examples of Computational Fluid Dynamics (CFD) analysis for climate control are also included. At the end, the road map toward 100 percent virtual prototyping and validation is presented."
Part Design and Material Selection for Single Shot Injection Molded Passenger Airbag Deployment Doors,"The passenger airbag (PAB) deployment door is a very critical component of the passenger airbag restraint system because of the many demands put upon the door. As an aid to those in the field who lack technical expertise and experience, this paper is intended to be a somewhat indepth set of guidelines for the part design and material selection for single shot injection molded PAB deployment doors. Disadvantages and advantages of this type of door are discussed. In regards to part design, some areas covered are size, hinge, tear seam, gap hiders, and surface. Environmental factors, mechanical properties, structural factors, and processing parameters -- all of which are important for material selection -- are defined and described."
HVAC Vacuum Duct Door,"The duct door (also referred to as “valve” or “flap”) which is used to regulate the air flow in a vehicle's HVAC system (Figure 1), has undergone a significant technological evolution since the early eighties. During the past decade, this evolution has centered on the raw materials used and on the manufacturing processes in order to gain in reliability and quality as well as in weight and cost reduction. Following the review of this evolution, we will present a new development: the vacuum duct door (“VDD”). This patented concept consists in activating the rotation of the door by creating an air depression, thereby doing away with the mechanical components utilized up until now for that purpose"
Measurement of Aeroacoustically Induced Door Glass Vibrations Using a Laser Vibrometer,"Work has been performed to study side glass vibrations of a typical automobile using a scanning laser vibrometer. The objective of this work was to achieve better understanding of the source and path mechanisms for aeroacoustically generated wind noise. As a tool for measuring aeroacoustically generated vibrations, the laser vibrometer presents many advantages over traditional methods. These advantages, discussed in this paper, include rapid setup, full field imaging, high spacial resolution, non-contact operation, and wide dynamic and frequency ranges."
Calculating the Loudness of Impulsive Sounds,"In this paper, a procedure for calculating the loudness of impulsive sounds is presented. Impulsive sounds are defined as short duration (< 500 msec), high energy sounds usually caused by an impact. Each of the six steps in this procedure are discussed in some detail. Validation of the method is obtained by psychoacoustic testing using both loudness matching and modified Levitt (up-down) techniques. The implementation of the impulsive loudness metric is then illustrated for door closing and power lock sounds."
Vehicle Closure Sound Quality,"This paper describes an investigation into the sound quality of passenger car and light truck closure sounds. The closure sound events that were studied included side doors, hoods, trunklids, sliding doors, tailgates, liftgates, and fuel filler doors. Binaural recordings were made of the closure sounds and presented to evaluators. Both paired comparison of preference and semantic differential techniques were used to subjectively quantify the sound quality of the acoustic events. Major psychoacoustic characteristics were identified, and objective measures were then derived that were correlated to the subjective evaluation results. Regression analysis was used to formulate models which can quantify customers perceptions of the sounds based on the objectively derived parameters. Many times it was found that the peak loudness level was a primary factor affecting the subjective impression of component quality. In several other cases, however, factors such as the length of the sound, the existence of multiple impacts, and sharpness proved to be more important for subjective preference. The resulting regression models can be used to quantify the sound quality of future closure hardware changes and guide engineers in the design of closure systems with optimal sound quality."
New Material for Supplemental Inflatable Restraint Doors,"New specialty urethane foams have been developed for use in composite type air bag doors (doors which consist of a vinyl skin, a foamed urethane core, and a supporting substrate). These air bag door foams are characterized by: high strength and tear resistance (much greater than typical instrument panel (IP) foam), good low and high temperature physical properties (required for varied deployment conditions) excellent heat aged physical properties (required for long life in vehicle service), and low vinyl staining rivaling good IP foam. Detailed descriptions of the air bag door foam physical properties are presented along with recent developments."
Aerospace Engineering 2004-09-01,"Marotta turns things around The valve-making company used to have trouble getting product out the door on time, but it has improved its turnaround dramatically via lean thinking. A view from the factory Manufacturing techniques and materials used in other industries may be debuting at aerospace factories near you. Reverse engineering Using digital processes accelerates design and increases manufacturing quality. Fine-tuning aerodynamics The aerospace industry relies on massive amounts of computing power to continually simulate, test, and optimize vehicles for reliability and accuracy."
Flexible “Skin” Senses Shear Force,"To date, it has been difficult or impossible for most robotic and prosthetic hands to accurately sense the vibrations and shear forces that occur, for example, when a finger is sliding along a tabletop, or when an object begins to fall. Some robots today use fully instrumented fingers, but that sense of touch is limited to that appendage, and its shape or size cannot be changed to accommodate different tasks. The other approach is to wrap a robot appendage in a sensor skin, which provides better design flexibility; however, such skins have not yet provided a full range of tactile information."
Disc Brake Squeal,"Chapters written by professional and academic experts in the field cover: analytical modeling and analysis, CEA modeling and numerical methods, techniques for dynamometer and road test evaluation, critical parameters that contribute to brake squeal, robust design processes to reduce/prevent brake squeal via up-front design, and more."
Up-Front Body Structural Designs for Squeak and Rattle Prevention,"Squeak and rattle is one of the major concerns in vehicle design for customer satisfaction. Traditionally squeak and rattle problems are found and fixed at a very late design stage due to lack of up-front CAE prevention and prediction tools. A research work at Ford reveals a correlation between the squeak and rattle performance and diagonal distortions at body closure openings and fastener accelerations in an instrument panel. These findings make it possible to assess squeak and rattle performance implications between different body designs using body-in-prime (B-I-P) and vehicle low frequency noise, vibration and harshness (NVH) CAE models at a very early design stage. This paper is concerned with applications of this squeak and rattle assessment method for up-front body designs prior to a prototype stage."
Aerospace Engineering 2005-08-01,"Global technologies Much of the excitement surrounding such aircraft as the point-to-point 787, hub-to-hub A380, and 7X business jet is due to the application of new technologies. Engineering a career With an impending shortage of aerospace engineers, industry and academia team to mold future engineering talent for an increasingly global environment. Taking research to the bank Behind the doors of BAE Systems' Advanced Technology Center. Testing toward perfection In a competitive global market, commercial aircraft need to be lighter, faster to market, cheaper to build, easier to maintain, and safer than ever."
Automotive Engineering International 2003-04-01,"Phantom materializes BMW's Rolls-Royce Motor Cars unveils its first model, an aluminum-bodied sedan with rear-hinged rear doors and a new V12. Protecting the cabin from powertrain NVH OEMs are getting help from suppliers such as Collins & Aikman and Bayer in damping NVH, thanks to innovation in plastics. Forced induction Environmental pressures prompt renewed interest in turbochargers and superchargers. Collaboration software emerges Interactive product development tools that can decrease design time and cost, enhance quality, and improve engineering processes are now widely available. Validated virtual testing DaimlerChrysler and MTS Systems have verified that component load histories can be predicted before prototypes are built. Automation: a tool, not an end Toyota and its suppliers try to strike a balance between automation and manual labor at their U.S. plants. Rouge: symbol of past points to future A rebirth at Ford's famous manufacturing complex honors the past but puts the focus on the future. Aluminum and the XJ Its construction and the techniques used to build it dominate the sixth-generation Jaguar sedan's technology story. Driving the Hy-wire GM's Larry Burns sees the alliance of fuel-cell and by-wire technologies as an essential element in the development of tomorrow's vehicles."
Automotive Engineering International 2005-11-01,"Frankfurt (Hybrid) Motor Show Dual-power technology was driven through the doors of the huge German complex in a way that has never been seen before. Bringing good things to light Emerging lighting technologies deliver more design flexibility as they get brighter, smarter, and smaller. Tightening supply chain links Improved electronic tools and more outsourcing fuel increased collaboration. Extreme two-wheeler engineering American Motorcyclist Association Superbike racing spurs development of truly super street bikes. Engineering for the aftermarket Suppliers that serve the OE market are setting their sights on the growing market for customization."
Two Projects and Free Advice,"A review of two particular projects from the '60s, will be presented. One pertains to doing a modal, before they were called that, using accelerometers and an oscilloscope for manual readout and graphing. The other relates to making best use of an early hardware design for best available noise control. The free advice will relate to presentations of data purporting to represent how people may judge in-vehicle sound and how we might learn about human response from the another industry."
An Advanced Optic Rear Vision Device for Motor Vehicles,"The outside rear view mirrors on motor vehicles are located outside a vehicle's solid body, normally attached to the side doors. Owing to their contour and positions, they present certain drawbacks which may cause dangers on the road, especially under unfavorable conditions when both the side door glasses and the surface of the outside mirrors are contaminated. An advanced optic rear view mirror unit has been designed and developed, with the aim to eliminate all the drawbacks of said outside rear view mirrors and hence to enhance the traffic safety. It shows that the said mirror unit eliminates the aerodynamic drags and sight blocks caused by the protrusion of conventional outside mirror bodies, places the rear vision inside a vehicle at a more logical physical position related to the driver, and provides an always clear view to the rear area regardless the outside weather conditions."
A New State-of-the-Art Keyless Entry System,"A new keyless entry system, for automotive security and comfort applications, has been developed. The system utilises a single chip transponder for vehicle immobilisation, keyless entry and remote control functionality. The transponder system can be embedded into a key fob or an ISO smart card. System security and communication speed is provided by an advanced anti-collision protocol in combination with sophisticated challenge response and uni-directional protocols. The system can be activated by using either a push-button transponder, where long range access to the vehicle is provided, or by touching an actuator near the door or trunk. Due to the inductive coupling between the transponder and the vehicle mounted antennas, the vehicle door or trunk opens on successful verification as if there were no locks. Additionally, inside the vehicle, the transponder can be used as an immobiliser."
Recycling of Mixed Color Automotive Thermoplastics,"A method for recycling of mixed color automotive thermoplastic scrap into appearance automotive interior parts has been developed and shown to satisfy the following three requirements: 1) material performance 2) color appearance, and 3) economically sound. The technique developed is based on minimal separation of the colors into hues (groups of similar colors) and repigmenting to the desired color. The studies included computer formulations, laboratory verifications and plant runs. Plant runs were carried out to produce automotive interior doors (base level S-truck) with polypropylene (PP) regrind and B-pillar 325 parts with acrylonitrile-butadiene-styrene (ABS) regrind at the Delphi - Adrian plant. Two colors, ruby red and medium gray, were selected because they are the most difficult colors to match. The results of the plant runs demonstrated that color matching can be successfully achieved. The total color difference in CIELAB color space (DE) of the recycled automotive parts to GM color standards was less than 0.87 with compositions of 20% and 30% of a one hue dominant PP and ABS regrind fraction at less than 2% pigment loading. The recycled automotive parts also met other requirements for mechanical and physical properties specified by the GM standards including GM's UV resistance requirements."
Total Interior Systems Integration,"The current and future greatness challenge for the car and light truck manufacturer is to develop less costly, weight efficient vehicles within shorter lead times. Based upon these circumstances, the technique of “systems design”, “systems integration” and “total interior systems integration” will be discussed in detail. Component integration and systems integration has been taking place in automotive interior design for sometime. However, total systems integration is relatively new. A potential area for interior systems integration application is in side impact “upgrade”. For added side impact protection the door structure and impact beam can be upgraded, a side air bag utilized, door/sill interlock, crushable arm rest, etc. Individually, each of these systems could meet the new side impact requirements; however, at a cost, weight and quality penalty. Utilizing two or more of these systems in combination could lead to an optimum solution (total systems integration). Other systems related to the body interior that can be designed by total systems integration are seats and I/P's. In addition to the interior system integration examples presented, a discussion will be presented regarding a new CAD design and CAM processing method called “morphing” which can enhance the optimization of systems integration."
Evaluation of Tailor Welded Blanks Through Technical Cost Modeling,"In the past decade, the demand for and development of tailor-welded blanks (TWBs) has increased dramatically. TWBs help reduce body mass, piece count and assembly costs, while potentially reducing overall cost. IBIS Associates, Inc. has performed a cost analysis of tailor welded blank manufacturing through the use of Technical Cost Modeling (TCM), a methodology used to simulate fabrication and assembly processes. IBIS has chosen the automobile door inner panel for comparison of TWBs and conventionally stamped door inners with added reinforcements. Manufacturing costs are broken down by operation for variable costs (material, direct labor, utility), and fixed costs (equipment, tooling, building, overhead labor, maintenance, and cost of capital). Analyses yield information valuable to process selection by comparing cost as a function of manufacturing method, process yield, production volume, and process rate."
Application of Fibre-Reinforced Composites in the Car Side Structure,"In this paper the general requirements for a passenger-car side door made of FRP are presented as well as a description of different concepts for self supporting monocoque FRP-doors. For one conceptual design static and dynamic analyses have been made to investigate more detailed the potential of composites in this application. The results of the structural analyses, which have been investigated by commercial FEA-codes, are presented. The research data resulting from completed testing of components are compared with the simulation results. On the basis of this research a prospect for the application of FRP in the field of side impact protection is given."
PVB Interlayer Performance Requirements for Laminated Side Glazing,"Laminated side glazing is a rapidly growing new application, driven by consumer demand for improved intrusion resistance and increased comfort. Performance requirements for movable door glass applications are different from laminated windshield (LWS) needs. Criteria for satisfactory performance are discussed and the performance of commercially available interlayers compared. Performance differences are significant, indicating that interlayer selection is critical for acceptable side glazing performance. The most important performance attribute is the ability to maintain adhesive bond strength to glass at the high interlayer moisture content present at exposed edges."
An Objective Measure of Severity for Small Topographical Defects in Automotive Paint,"In this evaluation eight observers viewed small topographical defects in paint samples out of doors and in a mock inspection facility. Each observer rated defect severity and the probability of returning a new vehicle with these defects to the dealer for repair. Severity ratings for defects viewed under the recommended inspection lighting were the same as those made outdoors. A nonlinear model relating the probability of a repair request to defect severity (R2 = .95) is provided. A method of measuring the essential physical attributes of the defect, specular highlight area and modulation, is described. A second model relating defect severity to the essential defect attributes (R2 = .88) is provided."
Static Electricity in Automotive Interiors,"Seats and carpets were evaluated for generating static charges on vehicle occupants. Active measures that eliminate or reduce static accumulation, and passive measures that dissipate static charge in a controlled manner were investigated. The active measures include using durable anti-static finishes or conductive filaments in seating fabrics. The passive measures include adopting conductive plastics in a steering wheel, seat belt buckle release button, or door opening handle. The effectiveness of these measures was tested in a low humidity environment."
Input Loading for Squeak & Rattle CAE Analysis,"A method to create a CAE load by utilizing the vibration motions at structure attachments has been developed. This method employs the concept of enforced motion as the constraints of boundary conditions to create an equivalent input force/moment matrix for a sub-structure with multi-point attachments. The main assumption is that motions at the attachments of the sub-structure should be the same as the known motions of the main structure under the generated input load. The key concept of the developed methodology is the calculation of the input dynamic compliance matrix for sub-structure attachment locations. This method is developed to create a system level input load to be used for squeak and rattle CAE analysis on a component or sub-system. It can also be used for minor component design change evaluation using only the component CAE model, yet as if it is assembled in the vehicle. It also enables the creation of CAE system level loads for non-structural trimmed body components such as the door trim panel and the floor console which are not included in a typical trimmed body CAE model. Two example cases are provided to show the usage and accuracy of the methods. The first example is a simple rectangular plate to serve as a benchmarking problem. The second one is an instrument panel on a typical sedan."
USING CROSS-LINKED OLEFIN FOAM IN AUTOMOTIVE INTERIOR PADDED TRIM COMPONENTS,"Considerable changes are occurring in automotive interior components in terms of design, aesthetics, and performance expectations. Consequently, new combinations of materials and production methods are being evaluated to meet these changing demands and requirements. One promising example of this is the use of a lightly cross-linked, olefin-blend foam sheetstock for many of the most visible interior padded trim components: door panels, instrument panels, consoles, glove-box/airbag doors, and seatbacks. Olefin foam sheet has a versatile processing profile using any of several interior-trim molding processes, including low-pressure molding, vacuum forming, compression molding, and structural reaction injection molding. In addition, the olefin foam offers excellent formability, with potential overall reduction of processing steps and systems costs. This paper describes the features and benefits of these new padded trim materials in different molding processes vs. competitive expanded polyvinyl chloride foams, including results of recent testing. Data on various skin/foam laminates are presented in terms of key properties required for each of the major processing methods for door trim panels and instrument panels."
A BE Model for the Analysis of the Effects of Seats in the Passenger Compartment Acoustic Behaviour,"The aim of this work is to validate a BE numerical methodology to calculate how the acoustic properties of seats can affect the acoustic behaviour of the passenger compartment of a vehicle. An analytical model, based on the Delany and Bazley approach, was implemented in order to simulate the acoustic impedance of the foam-fabric system. This model has been validated with absorption coefficient measurements on a certain number of foam-fabric combinations. The calculated impedance was used as input for a BEM analysis of the interior cavity of a trimmed vehicle. The measured impedance of trimming components as floor carpet, door panels and parcel shelf were included into the cavity model. The acoustic field due to a known source with and without seats was calculated, in the frequency range 20-400 Hz: the calculated FRFs are in good agreement with the measured ones. The analysis has demonstrated that the presence of seats does not improve the absorption of the passenger compartment in the frequency range investigated: the seats modify the peak position in the FRFs but do not lower their level. Reverberation time measurements made in the passenger cavity with and without seats have, on the contrary, put into evidence an important seat contribution in lowering the interior noise above 1000 Hz: the reverberation time in this frequency region has been reduced by about 50% by the presence of seats."
Use of FEA Concept Models to Develop Light-Truck Cab Architectures with Reduced Weight and Enhanced NVH Characteristics,"Many recent developments in automotive technology have resulted from the need to improve fuel economy without sacrificing passenger comfort or safety. This paper documents an effort to reduce the weight of dual-use military/civilian vehicles through the use of innovative design architectures. Specifically, a number of crossmember architecture concepts were developed for the cab floorpan of a light-duty truck. The floorpan is a key structural component of any vehicle, providing a significant contribution to noise, vibration, and harshness parameters such as stiffness and normal modes. Finite element concept models of the baseline cab and concept cabs are used to show that changes in the crossmember architecture can significantly reduce cab weight without compromising structural performance."
Continuously Produced Honeycomb Sandwich Materials for Automotive Applications,"The demands for automotive interior and exterior panels request an optimal combination of materials and cost efficient production processes. Mechanical and acoustical requirements and a weight target result today often in the selection of a sandwich design with a cost efficient and recyclable core material. Two new cost efficient honeycomb materials and their continuous production processes have been developed at the K.U.Leuven. These materials and production methods enable an automated in-line production of paper and polypropylene (PP) based honeycombs for automotive sandwich panels and parts. The production concepts, possible material combinations and basic material properties for automotive sandwich parts are presented."
Proposal on New Design of Laminated Glass for Weight and Cost Reduction,"This paper presents the proposal on the new design of laminated glass to solve the problems which conventional laminated glass will face when the adoption of laminated glass to side and rear windows extends even to mid-priced models from the safety and security requirements. The thermoset transparent adhesive foils tradenamed “EVASAFE” and the hard coated PET films which are the important elements enabling the proposed laminated glass are first introduced in details and then, the various test results on the proposed laminated glass are indicated and its advantages are made clear."
Panel Noise Contribution Analysis: An Experimental Method for Determining the Noise Contributions of Panels to an Interior Noise,"A new method for estimating the sound pressure level (SPL) at a defined position of the interior is presented. It is possible to recalculate the interior noise dependent on the sound radiated by specified panels which encloses the interior. It could be applied to analyse the interior acoustics under different operating conditions. This could be normal driving on real roads or pure wind noise inside wind tunnels. Also it is possible to study the interior noise under an artificial force excitation applied to the trimmed body. The method is based on the theoretical background of TPA (= Transfer Path Analysis /1/ ) via matrix inversion. It was tested on a simple cuboid structure with an artificial force excitation. The comparison of the measured and recalculated SPL of the interior shows a good correlation. Also the influence of some physical modifications at identified critical areas corresponds with the expected influence to the measured SPL inside this structure. After this first test, for a wind noise excitation a real car structure was investigated. Again the comparison of the measured and recalculated SPL inside the car shows a good correlation for a wide frequency range. At last the method is discussed dependent on possible applications and alternatives which can be used for determining the noise contribution of the panels. Also a perspective in next steps of development and further applications is given."
Automotive Noise and Vibration Control Practices in the New Millennium,"The approaches used to develop an NVH package for a vehicle have changed dramatically over the last several years. New noise and vibration control strategies have been introduced, new materials have been developed, advanced testing techniques have been implemented, and sophisticated computer modeling has been applied. These approaches help design NVH solutions that are optimized for cost, performance, and weight. This paper explains the NVH practices available for use in designing vehicles for the new millennium."
Full- and Model-Scale Scrutiny of the Effects of Vehicle Windshield Defrosting and Demisting on Passenger Comfort and Safety,"Maintaining adequate visibility at all times, through a vehicle windshield, is critical to the safe usage of the vehicle. The ability of the windshield defrosting and demisting system to quickly and completely melt ice on the outer windshield surface and remove mist formed on the inner surface is therefore of paramount importance. The objectives of this paper are to investigate the fluid flow and heat transfer on the windshield as well the effect of the air discharge from the defroster vents on passenger comfort. The results presented are from numerical simulations validated by experimental measurements both carried out a model and full-scale. The numerical predictions compare well with the experimental measurements at both scales. The effects of the defrosting and demisting air on occupants' comfort and safety are examined."
Automatic Demisting Control of Automobile Windshield Glass,"This paper describes the development of the control device for automatic demisting. The control is started from the mist possibility(MP) = 0, which is defined as the temperature difference between dew point and glass surface temperature. The control strategy for automatic demisting was installed in FATC unit and successfully demonstrated by the vehicle test in cold and hot chamber, ranging from 0° to 30°C."
Parametric Study on Automotive Windshield Defrost Pattern using CFD,"Prediction of automotive windshield defrost pattern using CFD is becoming increasingly important as a complement to cold chamber and field testing to achieve the improved windshield defrosting performance while reducing vehicle development time and cost. Although CFD simulation is popular and convenient, the efficiency and accuracy of simulation somewhat strongly depend on the simulation parameters such as choice of computational grid system, boundary conditions handling, flow consideration including turbulence model, and so on. In this investigation, parametric study on automotive windshield defrost pattern using CFD was performed about simplified passenger compartment. The objectives of this study are to examine the effects of each para-meter and derive the optimized simulation methodology of windshield defrost pattern."
Reducing Vehicle Auxiliary Loads Using Advanced Thermal Insulation and Window Technologies,"Advanced lightweight insulation and window technologies can contribute significantly to achieving industry and government goals of substantially improving fuel economy without loss of vehicle performance or passenger comfort. Two conventional passenger automobiles, a 2001 sport-utility vehicle (SUV) and a 1999 mid-size sedan, were retrofitted with lightweight insulation; the sedan was also fitted with specially designed windows. The body insulation and windows reduce heating and cooling loads, which allows downsizing of heating, ventilation, and air conditioning (HVAC) equipment. Benefits derived from the use of advanced insulation and window technologies include: Demonstrated reductions in cooling loads; Fuel savings for conventional and hybrid vehicles; Extended range for electric vehicles; Greatly improved passenger comfort; Reduced degradation of interior surfaces; and Improved safety. The research vehicles were retrofitted with Lawrence Berkeley National Laboratory's (LBNL) patented gas-filled panel (GFP) insulation. GFPs are multi-layer baffle constructions made from lightweight films and filled with a low-conductivity gas. These lightweight panels can be up to three times as effective as conventional foam insulations depending on the type of gas used. The GFPs used in the automobile retrofits had a krypton or xenon gas fill, which provides an effective thermal resistance of R-12 per inch and R-20 per inch, respectively. By comparison, expanded polystyrene has a thermal resistance of R-5 per inch. The solar-control glazings used in the sedan retrofit consist of special coatings, which create a narrow-band-pass filter that rejects ultra-violet and infrared (IR) wavelengths. The result is much less heat gain into the interior of the car and less degradation of interior surfaces. The retrofitted cars were tested under driving conditions in a wind tunnel and in an outdoor setting. Test results show that vehicle warm up under soak conditions (vehicle parked in the sun) was delayed compared to a factory vehicle."
Guidelines for Using Fast Multipole BEM to Calculate Automotive Exterior Acoustic Loads in SEA Models,"Automotive interior noise at mid and high frequencies is typically dominated by the airborne noise from acoustic sources that are spatially distributed around a vehicle. Each source is typically spatially compact (for example, a tire contact patch) but the source radiates sound that then propagates across the entire exterior surface of the vehicle. To characterize a source it is therefore necessary to know both the sound pressure level in the vicinity of the source and also the way in which sound from the source diffracts around the vehicle. The former depends on the details of the source, the latter typically depends on the overall vehicle geometry. When creating Statistical Energy Analysis (SEA) models of interior noise, the diffraction of airborne loads around a vehicle is often measured experimentally. Since SEA deals with averaged quantities, it is typically only necessary to obtain an approximate estimate of the space and frequency averaged sound pressure level across various surface regions of the vehicle (rather than a very detailed narrowband prediction of the diffraction). This paper provides a numerical investigation of the diffraction of typical acoustic sources around a vehicle using the Fast Multipole Boundary Element Method (FMM BEM). In particular, the paper investigates the sensitivity of the space and frequency averaged diffracted field to various modeling details (for example, geometric detail, mesh density/quality, surface impedance, frequency resolution etc.). The objective of the study is to investigate how much “detail” is needed in an FMM BEM model in order to get accurate predictions of the exterior acoustic loads for use in Statistical Energy Analysis (SEA) models. Significant reductions in computational expense can be obtained by matching the level of detail in the FMM BEM model to the level of detail required in the input results for an SEA model (and therefore avoiding “over computing” results that are subsequently frequency and space averaged)."
Development of a New Squeak and Rattle Detection Algorithm,"A new algorithm to detect and to quantify the seriousness of the detected squeak and rattle (S&R) events was developed. A T-F analysis technique called AWT, the Zwicker loudness model and leaky integration are employed to define new concepts we called transient specific loudness time histories and perceived transient loudness time history. The detection threshold of the perceived transient loudness was identified by a clever interpretation of jury test results. The proposed algorithm showed a good promise producing results that are well correlated with the jury tests. The new algorithm developed in this work will be able to automate detection and rating of the S&R events with good accuracy and with minimum possibility of false alarm under normal operating conditions"
Theoretical/Experimental Study on the Vibrations of a Car Engine,"The influence of the inertia properties (mass, centre of gravity location, and inertia tensor) on the dynamic behaviour of the engine-gearbox system of a car is studied in this paper, devoting particular attention to drivability and comfort. The vibration amplitudes and the natural frequencies of the engine-gearbox system have been considered. Additionally, the loads transmitted to the car body have been taken into account. Both the experimental and the theoretical simulations confirmed that the engine-gearbox vibrations in the range 10 - 15 Hz are particularly sensitive to slight variation of the inertia properties. The effects on engine-gearbox vibrations due to half-axles, exhaust system, pipes and inner engine-gearbox fluids have been highlighted."
Vehicle NVH Analysis Using EFEA & EBEA Methods,"The Energy Finite Element Analysis (EFEA) has been developed for computing the structural vibration and the interior noise level of complex structural-acoustic systems by solving governing differential equations with energy densities as primary variables. Results from EFEA simulations have been compared successfully with test results for Naval, automotive, and aircraft structures. The Energy Boundary Element Analysis (EBEA) has been developed for exterior acoustic computations using the acoustic energy density as primary variable in the formulation. EBEA results have been compared successfully to the test results in the past for predicting the exterior acoustic field around a vehicle structure due to external noise sources. In this paper, the EBEA and EFEA methods are combined for predicting the interior noise levels in a vehicle due to exterior acoustic sources. The EBEA is employed for computing the acoustic field around a vehicle structure due to exterior acoustic noise sources (i.e. tire source, engine source, etc.). The computed exterior acoustic field comprises the excitation for the EFEA analysis. The vehicle structure, the acoustic treatment, and the interior acoustic volumes are represented in the EFEA model. The interior noise level in the vehicle is computed by the EFEA. Predictions of interior noise level (expressed in a noise reduction format) are compared favorably with test results for two separate types of excitation."
High Frequency Vibro-Acoustic Analysis Using Energy Finite Element Method,"As an alternative method to Statistical Energy Analysis (SEA), Energy Finite Element Method (EFEM) offers several unique advantages for vibro-acoustic analysis of structural-acoustic systems. In this paper, the theory of the energy finite element method is overviewed. The main developments of a recently available EFEM code are presented. This is followed by the investigation of several example problems using EFEM; (a) the acoustic pressure computation in an acoustical duct, (b) the sound transmission loss of an automotive dash, and (c) the vibro-acoustic analysis of a truck cab. The EFEM predictions are compared to the analytical solutions, SEA predictions or test data and good correlations are observed. Further, the advantages of EFEM in the solution of high and middle frequency vibro-acoustic problems are discussed."
Probabilistic Reanalysis Using Monte Carlo Simulation,"An approach for Probabilistic Reanalysis (PRA) of a system is presented. PRA calculates very efficiently the system reliability or the average value of an attribute of a design for many probability distributions of the input variables, by performing a single Monte Carlo simulation. In addition, PRA calculates the sensitivity derivatives of the reliability to the parameters of the probability distributions. The approach is useful for analysis problems where reliability bounds need to be calculated because the probability distribution of the input variables is uncertain or for design problems where the design variables are random. The accuracy and efficiency of PRA is demonstrated on vibration analysis of a car and on system reliability-based optimization (RBDO) of an internal combustion engine."
Glass Debris in Rollover Accidents,"Vehicles involved in rollover accidents almost always leave a debris trail. This debris trail is useful for the accident reconstructionist; it assists with identifying the vehicle path during the rollover and the location and orientation of the vehicle at various vehicle to ground contacts. Often it is helpful to know when and where various vehicle windows fractured. This is possible by comparing glass obtained from the accident site with glass samples still attached to the accident vehicle. The limit of this analysis is controlled by the manufacturing tolerance of the vehicle glass and the specified pane thickness. This paper presents a series of measurements made on various automotive tempered windows and presents: 1) the thickness range in individual panes, and 2) the thickness variation seen from pane to pane in the same vehicle."
CAL STATE FULLERTON FINDS WINNING FORMULA IN COMBINING ART AND ENGINEERING,Team wins Generation Auto video contest in a year marked by great improvement in its Formula SAE performance. THE CHALLENGE: Create and submit a 1-2 minute video highlighting the diverse aspects of the automotive industry that make it an attractive or “cool” industry to work in. The qualification: Participate in an SAE International Collegiate Design Series event.
Modeling process and validation of Hybrid FE-SEA method to structure-borne noise paths in a trimmed automotive vehicle,"The Finite Element Method (FEM) and the Statistical Energy Analysis (SEA) are standard methods in the automotive industry for the prediction of vibrational and acoustical response of vehicles. However, both methods are not capable of handling the so called “mid frequency problem”, where both short and long wavelength components are present in the same system. A Hybrid method has been recently proposed that rigorously couples SEA and FEM. In this work, the Hybrid FE-SEA method is used to predict interior noise levels in a trimmed full vehicle due to broadband structure-borne excitation from 200Hz to 1000Hz. The process includes the partitioning of the full vehicle into stiff components described with FE and modally dense components described with SEA. It is also demonstrated how detailed local FE models can be used to improve SEA descriptions of car panels and couplings. After review of the Hybrid FE-SEA models of a full vehicle that were built, sample experimental validation results of interior SPL and panel vibration are shown."
Acoustic and Structural Treatment of Body-in-White,"Automotive body structures are developed to meet vehicle performance requirements primarily based on ride and handling, crashworthiness, and noise level targets. The body is made of a multitude of sheet metal stampings welded together. Other closures such as fenders, hood, doors and trunk lid are developed to match body interfaces, to contribute and participate in the overall vehicle response, and to meet the sub-system and system structural requirements. In order to improve performance and achieve weight reduction of the overall vehicle steel structure, new polymeric materials and treatment strategies are available to body structural engineers to optimize the response of the vehicle and to tune vehicle performance to meet specified functional requirements. If early integrated to the design cycle, these materials help not only improve the structural body response, but also decrease the weight of the integrated body structure."
Family of High Modulus (HMG) Nylon Based Plastics Increases Mileage and Reduce Weight,"Resent developments were oriented on two high-flow, high-modulus grades fiber-glass reinforced nylon 6 (HMG series) grades for transportation, autos and other industrial applications requiring high stiffness, high strength and high fatigue resistance. These materials combined the following improved technological (injection molding, vibration and hot plate welding, etc.) and mechanical performance properties such as greater dimensional stability, higher short-term (strength and stiffness) and long-term (fatigue and creep with the influence of temperature effects). Both HMG series grades Capron®1 HMG10 and Capron® HMG13 - are for injection molded parts where stiffness, strength, impact resistance, and good surface and improved appearance are preferred. The current and possible applications of these plastics includes auto mirror housing brackets, clutch pedals, clutch master cylinders, ski bindings, steering wheels, levers, auto seat frames, door handles and door lock mechanisms."
An Evaluation of Laminated Side Window Glass Performance During Rollover,"In this study, the occupant containment characteristics of automotive laminated safety glass in side window applications was evaluated through two full-scale, full-vehicle dolly rollover crash tests. The dolly rollover crash tests were performed on sport utility vehicles equipped with heat-strengthened laminated safety glass in the side windows in order to: (1) evaluate the capacity of laminated side window safety glass to contain unrestrained occupants during rollover, (2) analyze the kinematics associated with unrestrained occupants during glazing interaction and ejection, and (3) to identify laminated side window safety glass failure modes. Dolly rollovers were performed on a 1998 Ford Expedition and a 2004 Volvo XC90 at a nominal speed of 43 mph, with unbelted Hybrid II Anthropomorphic Test Devices (ATDs) positioned in the outboard seating positions. Vehicle dynamics, occupant kinematics, and glazing failure modes were evaluated through: on-board instrumentation, analysis of on-board and off-board high speed video and film, a survey of the evidence in the rollover debris field, and post-test inspection of the vehicle, ATDs, and glazing. Laminated side window safety glass did not prevent complete ejection of the ATDs. Five of the six ATDs in the Expedition were completely ejected from the vehicle, and 3 of the 4 ATDs were fully ejected in the XC90 test. Containment of the two ATDs that were not completely ejected was unrelated to glazing contact; the laminated window adjacent to each ATD vacated the window opening and both were partially ejected during the roll sequence. Side window glass fracture and failure was observed in association with ATD loading, ground contact deformation, and combinations thereof. On the basis of the performance observed in this study, it is concluded that heat-strengthened trilaminate glass is not a suitable candidate for occupant containment during rollover. Comparison of these full-scale rollover tests to prior laboratory-based evaluations of laminated side glass demonstrates that the prior studies fail to account for several aspects of the rollover environment, which contribute significantly to glazing loading, fracture, and failure."
CFD-based Modelling of Flow Conditions Capable of Inducing Hood Flutter,"This paper presents a methodology for simulating Fluid Structure Interaction (FSI) for a typical vehicle bonnet (hood) under a range of onset flow conditions. The hood was chosen for this study, as it is one of the panels most prone to vibration; particularly given the trend to make vehicle panels lighter. Among the worst-case scenarios for inducing vibration is a panel being subjected to turbulent flow from vehicle wakes, and the sudden peak loads caused by emerging from a vehicle wake. This last case is typical of a passing manoeuvre, with the vehicle suddenly transitioning from being immersed in the wake of the leading vehicle, to being fully exposed to the free-stream flow. The transient flowfield was simulated for a range of onset flow conditions that could potentially be experienced on the open road, which may cause substantial vibration of susceptible vehicle panels. As these conditions cannot generally be replicated in the wind tunnel, a comprehensive numerical simulation methodology is required if this issue is to be addressed before vehicle prototypes are built. Transient aerodynamic simulations were performed using a Lattice-Boltzmann Method (LBM) and several different approaches were used to create dynamic onset flow conditions approaching the vehicle, such as simulating a: instantaneous transition to a twenty-degree yaw crosswind; twenty-degree harmonic yaw at 10 Hz; flow behind a ‘bluff body’ turbulence generating grid; ‘passing disturbance’; vehicle in the wake of another vehicle, at a range of separation distances. A structural solver was used to predict the amplitude of vibration of the hood under these flow conditions. The amplitude response was largest when the frequency content of the oncoming flow matched the natural frequencies of the hood; the turbulence grid was found to produce the largest vibration for this reason. This study shows that transient aerodynamics simulation coupled with a structural solver can be used to predict the onset of vibration for different flow conditions, which could be encountered on the road but cannot be easily reproduced in the wind tunnel."
Validation of Interior Noise Prediction Obtained using Statistical Energy Analysis and Fast Multipole BEM,"Statistical Energy Analysis (SEA) is an effective tool for evaluating the acoustic performance of a vehicle structure and sound package. SEA is typically used to predict both interior noise levels and to set noise reduction targets for various components. A typical full vehicle SEA model includes acoustic loads from airborne sources such as engine, tire and exhaust noise [1]. Each source is typically spatially compact (for example, a tire contact patch) but the source radiates sound that then propagates across the entire exterior surface of the vehicle. In order to characterize a source it is therefore necessary to know both the sound pressure level in the vicinity of the source and also the way in which sound from the source diffracts around the vehicle. A companion paper has investigated the numerical prediction of the diffraction of acoustic sources around a vehicle using the Fast Multipole Boundary Element Method [2]. In this paper, the exterior loads predicted by the FMM BEM method are applied to a full vehicle SEA model and used to predict the interior noise within the vehicle. The results are compared with experimental measurements and good agreement is observed. Modeling guidelines and assumptions are presented and discussed."
Development of Sound Source Search Technology for High Frequency Noise in Vehicle Interiors,"Continuously variable transmission (CVT) and hybrid systems, which have metal belts and electrical units not found in conventional transmissions, are susceptible to extremely High Frequency belt and electromagnetic noise between 5 to 10 kHz. The evaluation and reduction of high frequency (HF) noise of 5 kHz and more is therefore a critical point for improving the quietness of vehicles installed with such systems. This article describes new sound source search technology capable of identifying sources of noise up to 15 kHz in the vehicle interior. Unlike conventional beamforming methods, this new system uses an improved microphone array provided with additional acoustic material. This article outlines the development of the system and its application to sound source identification of HF noise in a hybrid vehicle."
Why Thermoplastic Door Hardware Systems Make Economic Sense Now,"Engineering thermoplastics are widely used in a variety of automotive components systems because of their excellent balance of mechanical performance, design flexibility, aesthetics, parts integration, and low specific gravity. This combination of properties allows for the creation of highly integrated modules, which can increase assembly efficiency and reduce mass, part count, warranty and ergonomic issues, and systems costs. As a result, the use of engineering thermoplastic materials can enhance market competitiveness at a time of increased global competition. To evaluate the economic advantages of polymers in a specific vehicle system, a design for assembly (DFA) case study was conducted with the goal of determining the variable system cost case for a generic thermoplastic door module system vs. conventional-build door systems based on assembly savings gains. This paper will describe the study and show the results achieved."
An Alternative Approach to Robust Design: A Vehicle Door Sealing System Example,"Designing a high-quality door sealing system at low cost is an economic and technological engineering challenge. Robust design is a systematic and efficient technique to meet this challenge of design optimization for performance, quality, and cost. This technique, also called parameter design, focuses on making product and process designs insensitive (i.e. robust) to hard-to-control variations called noise factors. In this paper, we illustrate and apply the principles of robust design using a response model approach to a door sealing system design problem where vehicle interior sound is the primary response being studied. The Appendix contains a glossary of all italicized words for reference."
Measurement of Transient Vibrational Power Flow in a Car Door Panel Using Intensity Technique,"In a structure, the noise source does not always coincide with the origin of excitation. Vibrational energy is transmitted in the structure and noise is radiated from the surface. For noise and vibration control in beam or shell structures, it is important to clearly identify the excitation sources and vibrational energy transmission characteristics. In this paper, measurement of transient vibrational power flow in a car door excited by impact using the envelope vibration Intensity technique is described. Vibrational power flow caused by flexural vibration in the car door panel is measured with the three channel method. The vibrational power flow is expressed with vibration intensity vectors at each measuring point. Instantaneous distributions of measured vibration intensity vectors in the car door panel are shown in this paper. Temporal and spatial variations of the vibrational power flow are discussed."
Use of FCRASH in a Door Openability Simulation,"During frontal and rear end type collisions, very large forces will be imparted to the passenger compartment by the collapse of either front or rear structures. NCAP tests conducted by NHTSA involve, among other things, a door openability test after barrier impact. This means that the plastic/irreversible deformations of door openings should be kept to a minimum. Thus, the structural members constituting the door opening must operate during frontal and rear impact near the elastic limit of the material. Increasing the size of a structural member, provided the packaging considerations permit it, may prove to be counter productive, since it may lead to premature local buckling and possible collapse of the member. With the current trend towards lighter vehicles, recourse to heavier gages is also counterproductive and therefore a determination of an optimum compartment structure may require a number of design iterations. In this article, FEA is used to simulate front side door behavior. Ford guidelines require the side doors, hatches and lift gates to be designed to remain closed during 35 mph perpendicular front (fixed) barrier crash tests. These guidelines also require the side doors to be designed to be capable of being opened without tools after the impact. While earlier analytical techniques [2] to handle door openability were based on door aperture deformation computations, this work describes a technique that is based on more realistic approach which directly simulates the process of door openability itself, using a finite element simulation. Therefore, it enables the simulation of an actual door behavior during and after perpendicular fixed barrier impacts."
Development of a Door Test Facility for Implementing the Door Component Test Methodology,"This paper describes the development of an automated Door Test Facility for implementing the Door Component Test Methodology for side impact analysis. The automated targeting and loading of the door inner/trim panels with Side Impact Dummy (SID) ribcage, pelvis, and leg rams will greatly improve its test-to-test repeatability and expedite door/trim/armrest development/evaluation for verification with the dynamic side impact test of FMVSS 214 (Occupant Side Impact Protection). This test facility, which is capable of evaluating up to four (4) doors per day, provides a quick evaluation of door systems. The results generated from this test methodology provide accurate input data necessary for a MADYMO Side Impact Simulation Model. The test procedure and simulation results will be discussed. Other features and advantages of the automated Door Test Facility are: elimination of “cut and weld” of structural braces of the old process accommodation of passenger car and light truck doors through a wide range of SID rams “seating” adjustments synchronization of SID rams movement and loading rate “freezing” the forward movement of “bottomed-out” SID ram(s) to maintain constant force to prevent trim panel spring back automated retraction of SID rams upon test completion."
"Glazing Effects of Door or Deformations in Crashes, Part 2","The non-uniformity of temper of 27 motor vehicle door windows as measured by the polarization method is presented, illustrated by two photographs of windows between crossed polarizers. The tempered glass fracture characteristics of 11 Geo Prism door windows are illustrated by two video frames of the windows after fracturing by door deformation slowly applied at bumper level. The speed of some moderate sized fragments was measured to exceed 60 km/h, due to strain relief rather than contact by an intruding object. Glazing history is briefly summarized, with our support of the NHTSA conclusion that more than 1300 lives per year could be saved cost effectively by replacing tempered glass by an “advanced glazing.”"
Pressure Fluctuations in a Flow-Excited Door Gap Cavity Model,"The flow-induced pressure fluctuations in a door gap cavity model were investigated experimentally using a quiet wind tunnel facility. The cavity cross-section dimensions were typical of road vehicle door cavities, but the span was only 25 cm. One cavity wall included a primary bulb rubber seal. A microphone array was used to measure the cavity pressure field over a range of flow velocities and cavity configurations. It was found that the primary excitation mechanism was an “edge tone” phenomenon. Cavity resonance caused amplification around discrete frequencies, but did not cause the flow disturbances to lock-on. Possible fluid-elastic coupling related to the presence of a compliant wall was not significant. A linear spectral decomposition method was then used to characterize the cavity pressure in the frequency domain, as the product of a source spectral distribution function and an acoustic frequency response function. The method was used to assess the effects of modifying the cavity geometry, adding sound absorbing material, and blocking the cavity orifice."
Experimental Development of a Unique Door Cavity Sound Absorber,"Airborne sound traveling through vehicle doors was a significant source of unwanted noise entering the passenger compartment of Saturn vehicles. To reduce these sound pressure levels, several different noise controls were assessed using nonstandard acoustical tests. The noise controls tested include door trim absorbers, barrier watershields, and various noise controls applied in the door cavity. Only when the noise controls were applied in the door cavity were significant noise reductions seen. The final developed part for use in the door cavity further enhanced noise reduction by using a combination of sound absorption and sound transmission loss."
High Strain-Rate Tensile Testing of Door Trim Materials,"The objective of this study was to determine dynamic tensile characteristics of various door trim materials and to recommend a practical test methodology. In this study, Polypropylene (PP) and Acrilonitryl Butadiene Styrene (ABS) door trim materials were tested. Slow speed (quasi-static-0.021 mm/s) and high speed tests were conducted on a closed loop servo-hydraulic MTS system. The maximum stress of these materials increased from quasi-static to dynamic test conditions (as much as 100%). The dynamic stiffness of PP increased two times from quasi-static tests. No significant change in stiffness was observed for ABS during quasi-static and dynamic tests at different strain-rates. Quasi-static and medium strain-rate (10-20 mm/mm/s) tests may be adequate in providing data for characterizing the dynamic behavior of trim materials for CAE applications. Strain gages can be used to measure the quasi-static and in some cases, dynamic strain. Strain gage effect on material properties can be assessed by comparing the maximum stress from tests with and without strain gages."
"Sound Power Measurement in a Semi-Reverberant, Volume Deficient Chamber","Sound power can be determined using a variety of methods, but precision methods require the volume of the noise source to be less than 1% of the chamber volume leading to relatively large test chambers. Automotive torque converter performance and noise testing is completed in an enclosed metallic test fixture which inhibits the use of precision methods due to volume and space limitations. This paper describes a new method developed to accurately determine sound power of an automotive torque converter in a relatively small enclosure through characterization of the test environment. The test environment was characterized using two reference noise sources designed to represent torque converter noise output and physical geometry. Sound pressure levels of the sources were measured at multiple microphone locations and at three source amplitude levels to characterize the environment. Test results were analyzed statistically to determine the microphone positions that best represent the overall sound levels in the chamber. Optimum measurement positions were found to depend on source size but independent of source amplitude. Accuracy was determined based on the variance between the sound pressure levels at each microphone position. Sound power correction factors were found using sources of known sound power and the optimum microphone positions. The new method allows estimation of sound power of operational torque converters in a dynamometer test fixture."
"Acoustic Diagnostic Network Algorithms, their Description and Implementation from Concept into a Comprehensive Vehicle Optimization Program.","Acoustic Diagnostic Network Algorithms (DNA) are experimental methods that extract airborne acoustic characteristics from a motor vehicle and decompose this information into a set of networks from which the source, path and receiver noise sources and paths can be determined. Unlike traditional transfer path analysis Acoustic DNA takes the problem into the fine detail. It answers questions such as what, where and how does a vehicle's acoustic systems need to be changed in order to achieve any given objective. This paper describes the fundamental methodology and features together with how it has been implemented into a computer program that has been used successfully in over 50 vehicle projects within the Authors Research and Development group on a wide range of motor vehicles."
Understanding the aeroacoustic noise mechanisms and noise control techniques of roof rack systems,"Aeroacoustics is one of the top NVH concerns in the automotive industry. HEV/EV have increased the challenge in rebalancing wind noise, and SDC is pushing sound quality requirements to be significantly more demanding than they are in conventional ICE manually-driven vehicles. The most severe aeroacoustic phenomena in ground vehicles are the ones with a tonal nature. Roof rack systems are directly exposed to the airflow and generate broadband noise and a discrete aeolian tone. Typical crossbar profiles are variations over an elliptical profile, i.e. not as blunt as a circular cylinder, neither as thin as a wing section, and a particular solution optimized for one profile will prove less effective in different designs. Therefore, the objective of this project is to investigate the noise mechanisms involved in elliptical crossbars through actual acoustic measurements taken on track. The first part of the project correlated exterior acoustic pressure and intensity measurements taken on track and in an aeroacoustic wind tunnel with the objective of assessing accuracy and repeatability. Exterior sound pressure on-track has demonstrated good accuracy in capturing both narrow and broadband noise effects, despite the uncontrolled background noise. The crossbar wake interaction with the roof plane was investigated through local flow visualization and reference aeroacoustic measurements. The second part of the project compared the noise generated by an elliptical cylinder with that generated by a circular cylinder and a NACA 0012 airfoil with the same thicknesses and at the same operational conditions. Results have shown that the elliptical crossbar noise characteristics have similarities when compared to those of blunt bodies at low Reynolds numbers and wing sections at higher speeds. Different leading and trailing edge geometries demonstrated that the trailing edge is the key contributor to the aeolian tone, while the leading edge affects primarily the broadband noise. Noise control techniques such as Angle of Attack and two and three-dimensional Boundary Layer Tripping (BLT) were investigated. Positive and negative incidence angles presented opposite trends towards noise reduction and have proven to be ineffective at higher speeds. 2D and 3D BLT did not eliminate the main tone but reduced its amplitude and bandwidth. 3D BLT techniques have demonstrated an advantage over 2D BLT. Innovative solutions such as Perforation and active Trailing Edge Blowing (TEB) were assessed. Both Perforation and TEB were effective in reducing the aeolian tone but presented side effects such as high frequency whistling, thus requiring further geometric optimization."
Instructions for New Projects and Validation Guidelines of Tonneau Covers for Pickup Truck Bed,"The purpose of this paper is to suggest guidelines for new projects of soft tonneau covers for pickup truck beds made up of aluminum framework and soft coverage. As the main objective, this paper will make an overall about new accessories projects focusing on each one of the main components of the assembly. The target is to obtain a low cost tonneau cover with a great performance regarding functionality, water accumulation, sealing, noise, robustness, vibration and compatibility with another pick up box's accessories. This article also explores basic procedures for testing and validation of a new soft tonneau covers or a carry over one, with its use extended to a different pickup truck. It is one of the first technical documents about truck soft tonneau covers available, so few references could be found in technical databases. Into this scenario, this article had the objective of give an overall about the subject, offering basic information for new developments and being a start point for future and in-depth studies about this truck component."
CAA Application to Automobile Wind Throb Prevention Design,"When a window opens to provide the occupant with fresh air flow while driving, wind throb problems may develop along with it. This work focuses on an analytical approach to address the wind throb issue for passenger vehicles when a front window or sunroof is open. The first case of this paper pertains to the front window throb issue for the current Ford Escape. Early in a program stage, CAA (Computational Aeroacoustics) analysis predicted that the wind throb level exceeded the program wind throb target. When a prototype vehicle became available, the wind tunnel test confirmed the much earlier analytical result. In an attempt to resolve this issue, the efforts focused on a design proposal to implement a wind spoiler on the side mirror sail, with the spoiler dimension only 6 millimeters in height. This work showed that the full vehicle CAA analysis could capture the impact of this tiny geometry variation on the wind throb level inside the vehicle cabin. The independent wind tunnel effort came to the same conclusion, and the difference between the analysis and testing is only about 1 dB. With the implementation of this spoiler, the program target was finally met. The second case of this paper deals with the sunroof throb issue for an SUV. The work concentrates on the modeling method of wind deflectors made of meshed fabric material and carrying out CAA analysis to access the sunroof wind throb level. The result shows that CAA can predict very well the impact of the wind deflector made of meshed fabric material on the wind throb level, in line with the subjective evaluation on proving ground. In summary, this work manifests that CAA is a very effective tool for wind throb prevention design when hardware prototypes are not available."
Custom Configuration of a Vehicle Electrical Control System for Production and Service,"International Truck Engineering has incorporated a cab electrical system controller (ESC) into their vehicle design. This was done to facilitate a larger number of configurations with a simpler hardware design. The ESC makes use of SAE J1939 and J1708 to communicate with instrument cluster, door, power train and other modules. It also has various discrete inputs and outputs. A proprietary operating program written for the ESC uses a set of binary configuration structures stored in flash ROM and includes a proprietary “byte code” interpreter. The configuration describes how to process all I/O signals to/from a central data array, byte code to execute and the instrument cluster layout. Byte code operates on the data array between input and output processing. The switches and gauges in the instrument cluster plug into network modules. Due to the variability of the International Truck & Engine vehicle products, the content of the ESC configuration can vary widely from vehicle to vehicle. It is the IT (Information Technology) organization's task to provide a specific configuration for each ESC. Based on customer ordered features, the configuration must contain the proper byte code modules, I/O processing and cluster configuration information. IT must also select the proper switches, gauges and warning lights and their locations, as well as match the discrete I/O to signals on pre-existing wiring harnesses. The software and hardware included in the configuration must be validated to prevent software and hardware conflicts. In addition to the initial configuration, IT must also provide vehicle service support. This includes reconfiguration of the ESC for software updates, recall support and customer driven additions or modifications. The system that IT developed to solve these issues is discussed."
Closed-Loop Recycling of Monomaterial Door-Panel Systems,"Pressures to increase the recyclable and recycled content of passenger vehicles are accelerating. In Europe, there is interest in eliminating halogenated polymers. Globally, more and more concern is focused on materials and methods that are ecologically friendly. Automakers and their suppliers are being encouraged to design and assemble components in new ways to facilitate separation, identification, and resource recovery at the end of the vehicle’s useful life - something that is not only good for the environment, but also the bottom line. One area of the vehicle that has proved challenging for applying such design for disassembly and recycling (DFD/R) principles has been the interior, owing to the sheer number of materials used there, and the great number of laminate structures that make disassembly nearly impossible. A good example is a door panel inner, which typically consists of a rigid plastic substrate, a foam pad, and a vinyl, leather, or cloth covering. This component is usually comprised of different materials tied with adhesives and polyester scrim fabrics. Fortunately, recent material developments as well as process enhancements have now made it possible to quickly and efficiently manufacture all-olefin door panels without adhesives or scrim, making the monomaterial door panels excellent candidates for recycling. But how recyclable are these systems? A recent manufacturing study successfully recycled fully covered door-trim panels comprised of an olefin-based coverstock, a cross-linked olefin foam pad, and a polypropylene (PP) substrate. Processing scrap was chopped and reintroduced - at predetermined weight ratios - back into the virgin resin feedstream used to produce additional PP door substrates. A variety of tests were performed both on plaques and full door panels comprised of varying ratios of virgin + recycled material to see if the presence of the recycled material affected any physical or mechanical properties, processability, or other engineering specifications. The results of this testing program are presented here, along with recommendations for implementing a closed-loop recycling program."
An Integrated Automobile Keyless Operation System,"An integrated automobile keyless operation system is developed. The system consolidates the ignition key and lock/switch, security and keyless entry and other functions into one unit. The system uses a small handheld portable wireless remote controller to replace the ignition key, the door key and the trunk key. A receiver replaces the ignition switch and functions as controlling switches for door-locks and/or trunk-lock. The system incorporates the latest advancement in wireless technologies and digital-signal processing. By consolidating components, the design cuts manufacturing cost, improves reliability and offers outstanding convenience and enhanced security."
Sensory Evaluation of Commercial Truck Interiors,"Vehicle interior harmony is related to human factors but it deals with human emotional attachment to the product. Kansei, or sensory engineering provides an effective approach to address harmony issues. This paper reports a preliminary investigation of human sensory evaluation of commercial truck interiors, especially the door interiors. To investigate the end users' needs and preference, a questionnaire survey was administered to twenty-six commercial truck drivers. Responses on usability, styling, harmony, and ergonomics issues of each driver's own truck were recorded. Furthermore, a set of 12 semantic differential scales, together with a preference ranking scale, was served to evaluate six truck door interiors. Results show that commercial truck drivers are more concerned with functionality and usability than styling and visual harmony. However, concerns on interior styling and harmony represent more than one-third of the design issues reported by the participants, indicating that interior harmony issues should not be overlooked. Three factors of door interior visual harmony were identified: color and emotion, geometric shape, and spatial arrangement. The color and emotion factor showed a high correlation with preference ranking merit value. Future work will be carried out to associate principal harmony factors with design parameters of door interiors."
Foresight Vehicle: Large Area Flexible Circuits for Automotive Applications Manufacturing Technology - A Review of Process Options,"It is the intention of motor vehicle manufacturers to achieve weight and cost savings by replacing wiring harnesses with flexible printed circuits in doors, roof liners, boots and cockpits. These circuits will be required in high volume and must meet the requirements of the vehicle and equipment suppliers with respect to cost effectiveness and reliability while presenting an achievable, economically sound manufacturing technology to the circuit suppliers. Design issues include requirements for CAN-bus1, EMC/RFI protection, 42 volt systems and the integration of functional modules 2,3,4. Alternative construction options and criteria for their assessment are proposed. The range of processes from which a manufacturing technology can be established are identified and discussed. The challenges presented to available processes and equipment by the potentially very large circuits are examined."
A Development Procedure to Improve the Acoustical Performance of a Dash System,"This paper discusses a development procedure that was used to evaluate the acoustical performance of one type of dashpanel construction over another type for a given application. Two very different constructions of dashpanels, one made out of plain steel and one made out of laminated steel, were studied under a series of different test conditions to understand which one performs better, and then to evaluate how to improve the overall performance of the inferior dashpanel for a given application. The poorly performing dashpanel was extensively tested with dashmat and different passthroughs to understand the acoustic strength of different passthroughs, to understand how passthroughs affect the overall performance of the dash system, and subsequently to understand how the performance can be improved by improving one of the passthroughs."
Massive Point Cloud Data Sets and Single Point Measurement Acquisition in the Production Floor Environment,"In typical production lines of automotive manufacturers, body parts are produced every several minutes. Sample parts are measured at certain intervals with a CMM machine at approximately 30 points to verify correct production. The points measured on each sample part are compared with reference points of a golden part or with the CAD model. This paper presents results achieved with a high-accuracy non-contact 3D measurement system capable of measuring both the full surface of sample parts and surface points (surface point measurement, or SPM), after production, on the production floor. The technology used enables high-speed image acquisition of large data sets together with CMM-like capability of measuring individual points, both accomplished simultaneously. SPM measurement of a car door requires approximately 15 minutes; measurement of a full door surface, including SPM, requires less than 1 hour if operated manually, or alternatively 3 minutes for SPM and approximately 10 minutes for full surface measurement if performed by a robot-based system. The system is capable of measuring shiny, oily and/or dirty parts, which makes it suitable for measurement right on the production floor. The resulting surfaces and points measured are aligned to vehicle coordinates by the system, and compared to the CAD design. SPMs are compared to their reference points, and reports are exportable. Examples of series of COP/CAD comparisons will be presented, taken on the production floor, illustrating the gradual development of a production defect and its detection with the full surface data. Such defects can immediately be found, when measuring the entire surface of each part, during production (in process). Corrective action can be taken before inaccuracies get out of control."
A Method to Determine the Power Input Associated with Rain Excitation for SEA Models,"Statistical Energy Analysis is used to predict the sound pressure level (SPL) in the interior of the vehicle. This is accomplished by knowing the energy sources (tire, engine, wind, etc) affecting the interior as well as the acoustic performance (absorption and transmission loss) of the interior trim components (headliner, door panels, instrument panel, etc). One of the noise sources that has not been seriously examined to-date is panel excitation by precipitation. The excitation of the roof due to raindrops can be a major noise source. Knowing how to properly model this power input would help analyze different headliners or roof treatments to minimize the SPL in the interior cavity. This will involve computational determination of mass, speed, and energy of standard water droplets for one of rain condition. A power spectrum is presented for one rain intensity condition on a test fixture."
E-Modularization of Rear Closures: Integration of New Generation of Electrical Systems,"This paper presents the potential for rear closure submodules. Side door modules and lightweight rear closures have attracted a lot of attention in recent years. However the characteristics of future liftgates allow the design of specific mechatronic sub-modules (e-modulesTM). Beside structure, rear closures satisfy three main functions: rear vision, rear signaling and rear access. All are undergoing a generation change that will be outlined in the first part of this paper, system by system. Each time the rationale behind modular integration, whether electronic or mechanical, will be reviewed. The second part presents examples of e-modulesTM that illustrate the potential gains in terms of ease of assembly, packaging optimization and network integration."
Development of Composite Body Panels for a Lightweight Vehicle,"Recently weight reduction is increasingly needed in automotive industry to improve fuel efficiency and to meet a CO2 emission requirement. In this paper, we prepared composite body panels for the lightweight vehicle based on a small passenger car. Fender, roof, door, side outer panel, and tailgate are made from hand layup using a glass/carbon hybrid reinforcement. Hood is made from low pressure sheet molding compound (SMC) to investigate feasibility of mass production. Both hand layup and low pressure SMC materials are newly developed and their physical properties are examined. CAE simulation was done for strength analysis and optimization of thickness for the body panels."
A New Wavelet Technique for Transient Sound Visualization and Application to Automotive Door Closing Events,"Transient automotive sounds often possess a complex internal structure resulting from one or more impacts combined with mechanical and acoustic cavity resonances. This structure can be revealed by a new technique for obtaining translation-invariant scalograms from orthogonal discrete wavelet transforms. These scalograms are particularly well suited to the visualization of complex sound transients which span a wide dynamic range in time (ms to s) and frequency (∼100Hz to ∼10kHz). As examples, scalograms and spectrograms of door latch closing events from a variety of automotive platforms are discussed and compared in light of the subjective rankings of the sounds."
Percentile Frequency Method for Evaluating Impulsive Sounds,"The Percentile Frequency method originated in an attempt to quantify the frequency content of door slam sounds. The method is based on the Specific Loudness Patterns of Zwicker Loudness. Zwicker states that the area of the Specific Loudness Pattern is proportional to the total loudness. The method summarizes each Pattern as seven frequencies identifying the contributions of fixed percentages of the total area (i.e. 10%, 20%, 30%, 50%, 70%, 80% and 90%). Applying the method to each Pattern in a time series generates a family of curves representing the change in relative frequency content with time. The process, in effect, normalizes the frequency content of the impulse for loudness and reduces the data to a two dimensional plot. On a Percentile Frequency plot a simple impulse appears as a pattern of “nested, inverted check marks.” More complicated impulses, such as rattles, have more complicated shapes that are still “nested” together. Applying this understanding to practical problems, the method has been used to visually show the progress of a project to reduce rattles occurring in door slam sounds. The method also has been used to quantify the low pitched “thump” of a door slam sound. In addition, a further extension of the method has been successful in differentiating high pitched door latch closing sounds. By incorporating these techniques into a general door slam sound test, it should be possible to evaluate objectively for rattles, latch sound, and “thump” as well as loudness."
Door System Design for Improved Closure Sound Quality,"Door closing sounds are an important element of the craftsmanship image of a vehicle. This paper examines the relationship between closure sound quality and door system design. The perception of door closing sound quality is shown to be primarily related to it's loudness and sharpness. Of the two, sharpness is more important than loudness. Other factors, like ring-down may also affect closure sound quality. The door system is made up of a number of components. The most important in terms of sound quality are the door and body structure, latch, and door seals. Each of these are classified as either a sound source, a transmission path or a sound radiator. Methods for improving the design of these components for good closure sound quality are discussed in some detail."
A Study on The Hybrid Finite Element Modeling for Side Impact Simulation,"In this study we suggest simplified and design oriented hybrid modeling methodology to the development of crashworthy structure. This hybrid model consists of main structure, which are modeled by beam and springs and doors modeled by shells. The main structures such as B-pillar roof rail and side sill are represented by nonlinear springs which have the same section properties as shell model have. The localized collapse of main structures are represented by non-linear spring elements whose moment-rotation characteristic is calculated based on Wierzbicki’s equation. The joint parts are represented by non-linear springs, which have the same moment-rotation characteristics as those of real parts to hold actual collapse characteristics. To represent force transition between structure and door, anti-sliding shells are introduced in the area of side-sill and lower part of Bpillar. Using this hybrid modeling methodology, we can get a good correlated result for full model and reduce calculation times around 80% for full FE shell model."
CFD Simulation of Side Glass Surface Noise Spectra for a Bluff SUV,"Simulation of local flow structures in the A-pillar/side glass region of bluff SUV geometries, typical of Land Rover vehicles, presents a considerable challenge. Features such as relatively tight A-pillar radii and upright windscreens produce flows that are difficult to simulate. However, the usefulness of aerodynamics simulations in the early assessment of wind noise depends particularly on the local accuracy obtained in this region. This paper extends work previously published by the author(1) with additional data and analysis. An extended review of the relevant published literature is also provided. Then the degree to which a commercial Lattice-Boltzman solver (Exa PowerFLOW™) is currently able to capture both the local flow structure and surface pressure distribution (both time averaged and unsteady) is evaluated. Influential factors in the simulation are shown to be spatial resolution, turbulence and boundary layer modelling. It is demonstrated that, whilst reasonable predictions are obtained for the surface noise spectra, both the size and strength of the A-pillar vortex are substantially over-predicted. Finally an attempt is made to estimate the frequency range that the simulation could be reasonably expected to capture. This analysis suggests that the simulation is bounded by the limitations of the turbulence model, rather than spatial resolution."
Low-Cost Audio for Automobiles,"Much design effort is given to the development and tuning of high-end automotive audio systems. Typically, premium speakers, separate amplifiers and careful tunings are used to create very high audio performance levels. Lower cost vehicles and vehicles of lower trim levels often feature more ordinary speakers and no separate amplifier. This typically leaves a number of listeners with little option for enjoying adequate bass performance, improved stereo imaging, etc. Small changes in acoustical component features and specifications can produce significant returns in spectral performance. Additionally, low-cost, powerful audio digital signal processing (DSP) has made its way into modern receivers. As the processing power of these devices improves, there are new opportunities for lower-level vehicles to produce customer-pleasing levels of audio performance. This paper addresses issues facing designers of lower-end audio systems and proposes solutions for potentially vexing problems such as those caused by non-linear speaker excursion. Informal listening test results from expert and non-expert listeners are also included."
Study and Application of Prediction Method for Low Frequency Road Noise,"When a vehicle drives over road seams or a bumpy surface, low-frequency noise called drumming is generated, causing driver discomfort. The generation of drumming noise is closely related to the vibration characteristics of the suspension, body frame, and body panels, as well as the acoustic characteristics of the vehicle interior. It is therefore difficult to take measures to get rid of drumming after the basic vehicle construction has been finalized. Aiming to ensure drumming performance in the drawing review phase, we applied the Finite Element Method (FEM) to obtain acoustical transfer functions of the body, and Multi Body Simulation to get suspension load characteristics. This paper presents the results of the study of drumming prediction technology using this hybrid approach. The paper also describes the results of 1) analyzing actual driving behavior when drumming occurs using a multi-point simultaneous measuring system, 2) analyzing suspension vibration characteristics as a cause of drumming, and 3) validating the correlation between the FEM model and an actual vehicle using Robot-controlled 3D Scanning Laser Vibrometers. Modifications made to the actual body structure are also introduced as a case study on effective drumming reduction."
An Iterative Approach Based on Prony's Method to Calculate the Surface Impedance of Acoustic Materials Measured in situ,"In many cases the in situ measurement of the absorption coefficient requires an iterative method for the correct calculation of the surface impedance of a sample. This happens because when spherical waves reflect on a sample's surface the pressure field above it is a function of the sample's surface impedance. As the pressure field involves an integral term, numerical integration is required in the iterative algorithm, which can be time consuming. The aim of this paper is to present an iterative approach based on Pony's method, which instead of numerical integration uses a series expansion with a few terms. Therefore the time of processing is decreased. Besides the description of the method, simulations and measurements (with a p-u probe inside an office room and a car) are presented. A comparison, with numerical integration, regarding the accuracy and the time of processing of Pony's method is also discussed."
Auditory Localization of Backup Alarms: The Effects of Alarm Mounting Location,"Sound localization of a backup alarm is important in situations when vehicles are reversing. Previous work has demonstrated the effects of ambient noise level and the spectral content of the backup alarm on localization. In the current study, we investigate the effects of backup alarm mounting location on localization performance. To address this question, we asked blindfolded listeners to localize backup alarms installed in positions that provided either direct (e.g., installed on the outer rear aspect of the vehicle) or indirect (e.g., installed within the inner frame rails of the vehicle) sound propagation paths to the listener. Additionally, we explored the effects of ambient noise level and the direction of origin of the alarm (behind, in front of, or to the left or right of the listener), and the interactions among all three factors (alarm location, ambient noise, and alarm direction relative to the listener). Localization performance was examined in terms of percent correct localization, as well as percent front-back confusion errors. When the alarm stimuli were presented in front, the alarm that was mounted directly in front of the listener -- providing a direct path to the listener --produced more correct localizations than the other alarms. This direct-path alarm also resulted in the least front-back confusions overall. However, when the alarm stimuli were presented behind the listener, the alarm mounted at the top of the rear of the truck --providing a direct but elevated path to the listener -- produced the worst performance and the most front-back confusion errors. An important factor affecting listeners' localization performance was the orientation of the listener relative to the direction from which the alarm stimuli originated. When the alarm was to the right or left of the listener, all alarm mounting locations produced equally good performance and no front-back confusions. Alarms originating from behind the listener, however, generally produced the worst performance, and the most front-back confusions, for the majority of the alarm mounting locations."
Efficient CFD Simulation Process for Aeroacoustic Driven Design,"The transport industries face a continuing demand from customers and regulators to improve the acoustic performance of their products: reduce noise heard by passengers and passersby; avoid exciting structural modes. In both the aerospace and automotive areas, flow-induced noise makes a significant contribution, leading to the desire to understand and optimize it through the use of simulation. Historically, the need for time-consuming, computationally expensive transient simulations has limited the application of CFD in the field of acoustics. In this paper are described efficient simulation processes that, in some instances, remove the requirement for transient analyses, or significantly reduce the total process time through intelligent pre-processing. We will outline this process and provide both automotive and aerospace industrial examples, including analyses of highly complex geometries found in real life. Section 2 describes a modeling hierarchy which includes steady-state, transient and frequency-based time-periodic methodologies. Section 3 contains four popular classes of application spread across the transportation sectors: - Airframe noise simulation of a complex nose landing gear; - Aeroacoustics of avionic cooling rack in an Airbus cockpit; - Automotive sunroof buffeting with structural impedance; - Fan noise signature in the presence of gusts. For these case studies, the main focus is the prediction of aeroacoustic noise sources. The propagation of noise to the far-field is not considered here, though some qualifying comments are made in section 2.4."
Optimization of Bus Body Based on Vehicle Interior Vibration,"In order to solve the abnormal vibration of a light bus, order tracking analysis of finite element simulation and road test was made to identify the vibration source, finding that the rotation angular frequency of the wheels and the first two natural frequency of the body structure overlaps, resonance occurring which lead to increased vibration. To stagger the first two natural frequency and excitation frequency of the body, thickness of sheet metal and skeleton of the body-in-white were chosen as the design variables, rise of the first two natural frequency of the body-in-white as the optimization objective, optimal design and sensitivity analysis of the body-in-white was carried out with the modal analysis theory. Combining with the modal sensitivity and mass sensitivity of sheet metal and skeleton, the optimum design was achieved and tests analysis was conducted. Comparing the test results before and after optimization, the effectiveness and rationality of the optimization is verified."
Assessment of a Vehicle's Transient Aerodynamic Response,"A vehicle on the road encounters an unsteady flow due to turbulence in the natural wind, due to the unsteady wakes of other vehicles and as a result of traversing through the stationary wakes of roadside obstacles. There is increasing concern about potential differences between the steady flow conditions used for development and the transient conditions that occur on the road. This paper seeks to determine if measurements made under steady state conditions can be used to predict the aerodynamic behaviour of a vehicle on road in a gusty environment. The project has included measurements in two full size wind tunnels, including using the Pininfarina TGS, steady-state and transient inlet simulations in Exa Powerflow, and a campaign of testing on-road and on-track. The particular focus of this paper is on steady wind tunnel measurements and on-road tests, representing the most established development environment and the environment experienced by the customer, respectively. Measurements of the surface pressure on the front sideglass were used for comparisons as this area exhibits a complex flow which is highly sensitive to yaw angle and which is also an important region, for wind noise considerations in particular. It was found that, if the transient on-road environment is known then steady-state wind tunnel measurements can be used to predict accurately the transient surface pressures, provided the methodology is sufficiently rigorous. Admittance or transfer function techniques are commonly used to compare transient and steady-state results and the limitations of these methods are shown here when the spectra of self-excited and externally imposed unsteadiness overlap. A new method is introduced to obtain a “true” transfer or admittance function, unconfused by the presence of self-excited unsteadiness. The aerodynamic admittance was found to be close to unity up to a frequency of 2-10 Hz and it then drops progressively."
A Comparative Study of Automotive Side Window Occupant Containment Characteristics for Tempered and Laminated Glass,"This study investigates occupant containment characteristics of tempered and laminated automotive moveable side glass in rollover collisions. FMVSS 216 test protocols were used to induce roof damage or sheet metal damage around the window opening in Lincoln Navigators equipped with tempered and laminated side glass. Dummy-drop tests were then performed to investigate relative containment. The results demonstrate that, for rollovers in which the window structure is compromised, tempered side glass and laminated side glass perform comparably relative to occupant containment. Also discussed are the general strength characteristics of different types of glass construction, the availability of laminated side glass in recent model U.S. vehicles, and anecdotal data supporting the conclusions of testing."
On the Use of the Fast Multipole Method for Accurate Automotive Body Panel Acoustic Load Predictions,"Knowledge of the external sound field around a car body is critical for vehicle acoustic development. Airborne isolation predictions, and thus panel and trim design depend on this data. Nowadays, such information is the result of experimental methods, as previously investigated simulation solutions proved either too costly, or not precise enough. In this paper, we investigate the use of a method combining computational efficiency and results accuracy: the Fast Multipole Method. This boundary-integral method uses an iterative solver and does not require a full assembly and factorization of the system matrix, thus allowing precise calculations over an extended frequency range even for large objects. In the present study, we demonstrate the potential of the method on a mid-range van, the Renault Scenic."
SEA Model Development Considerations for Cost-Driven or Developing Market Vehicles,"In South America and other developing markets the NVH development of a vehicle is often limited by the cost of the sound package components. In an era where cost reduction is crucial not only in developing markets, but also in developed markets where any cost or weight savings is a large competitive advantage, lessons learned from considerations for NVH analysis for vehicle design in developing markets can be applied to vehicle NVH design everywhere. A Statistical Energy Analysis (SEA) model was used to target and identify the dominant paths in need of sound package modifications to decrease the over sound pressure levels and also to identify paths in which sound package (and cost) could be reduced or deleted with no discernable degradation to the overall interior levels. This model will be used to support or challenge ongoing proposed sound package modifications to the vehicle and serve as a baseline template for design phase work for other vehicles of a similar body style."
Contribution Analysis of Vehicle Interior Noise Using Air-borne Noise Transfer Function,"The efficient insulation of noise transmitted from the powertrain is one of the important issues in developing the variation or minor change of the vehicle. This paper deals with the contribution analysis of each path of interior noise by window mask method using air-borne noise transfer function and shows the application of Taguchi method in finding the best combination of the insulation countermeasures. To this aim, the vehicle interior cabin is segmented into 25 windows and the air-borne noise transfer functions between source and receiver points are measured by acoustic reciprocal method."
Investigation of Factors Influencing Vehicle Audio Speaker Locations for Better Sound Quality and Spread,"The NVH performance of today's automobiles has been improved to levels where common user can easily perceive the issues related to sound quality inside the passenger compartment. With NVH development resulting in quieter and quieter driving conditions, the importance of better acoustic in car-entertainment has been improved by 2-3 notches. The focus of this paper is further concentrated on the methodology to evaluate and optimize speaker location in a MPV. The speaker location was optimized for its location inside passenger compartment and its mounting characteristics. Two different configurations of speaker fitment locations for different seating patterns were tested in vehicle. Frequency Response Function and sound quality parameters were measured experimentally and calculated using sound quality algorithm respectively. The optimal position of speaker location is then determined by analyzing the data for a) uninterrupted reach of the signal to all passenger locations throughout its frequency range. b) Noise contamination of the source because of reflections from nearby interior components. c) Influence of support stiffness on the source contamination. The evaluation methodology was established as a standard practice for using on different vehicles for speaker location optimization."
Operating Noise Synthesis on a Class 8 Truck Cab,"The objective of this work was to synthesize the time and space average operating airborne noise excitation field from discrete noise sources, to the exterior surfaces of a Class 8 truck cab while operating fully loaded at 60 mph. This noise field was subsequently used as input to a statistical energy analysis (SEA) model, for designing a sound package to reduce interior noise. As a relatively simple and inexpensive alternative approach to direct measurements using a heavy-duty chassis dynamometer in a semi-anechoic chamber, the method nevertheless provided an acceptable input for the SEA development work."
Using the Hybrid FE-SEA Method to Predict Structure-borne Noise Transmission in aTrimmed Automotive Vehicle,"A Hybrid method that rigorously couples Statistical Energy Analysis (SEA) and Finite Element Analysis (FEA) has been used to predict interior noise levels in a trimmed vehicle due to broadband structure-borne excitation from 200Hz to 1000Hz. This paper illustrates how the Hybrid FE-SEA technique was applied to successfully predict the car response by partitioning the full vehicle into stiff components described with FE and modally dense components described with SEA. Additionally, it is demonstrated how detailed local FE models can be used to improve SEA descriptions of car panels and couplings. The vibration response of the untrimmed body-in-white is validated against experiments. Next, the radiation efficiency and vibration response of bare and trimmed vehicle panels are compared against reference numerical results. Finally, interior noise levels in bare and trimmed configurations are predicted and results from a noise path contribution analysis are presented."
CAE Interior Cavity Model Validation using Acoustic Modal Analysis,"The ability to predict the interior acoustic sound field in a vehicle is important in order to avoid or to minimize unwanted noise conditions, such as boom or high pressure levels at cavity resonance frequencies. In this work an acoustic modal analysis is carried out for a minivan. The testing procedure is discussed and some results are shown. With the seats removed and for low frequencies the interior of the vehicle is similar to a rectangular box for which an analytical solution exists. At higher frequencies and with the seat, the interior acoustic field displays complex mode shapes."
Root Cause Identification and Methods of Reducing Rear Window Buffeting Noise,"Rear Window Buffeting (RWB) is the low-frequency, high amplitude, sound that occurs in many 4-door vehicles when driven 30-70 mph with one rear window lowered. The goal of this paper is to demonstrate that the mechanisms of RWB are similar to that of sun roof buffeting and to describe the results of several actions suspected in contributing to the severity of RWB. Finally, the results of several experiments are discussed that may lend insight into ways to reduce the severity of this event. A detailed examination of the side airflow patterns of a small Sport Utility Vehicle (SUV) shows these criteria exist on a small SUV, and experiments to modify the SUV airflow pattern to reduce RWB are performed with varying degrees of success. Based on the results of these experiments, design actions are recommended that may result in the reduction of RWB."
Prediction and Improvement of High Frequency Road Noise of a Mid-Size Sedan,"An airborne SEA model to predict high frequency interior noise is built for a mid-size sedan. The 60 KPH running condition is simulated based on this model and then the corresponding result is compared to the measured interior noise. A very similar prediction is found. Also, weak points of sound insulation and effective absorption area in this vehicle are identified using the model. It is shown that in an early design stage and when the proto vehicle is not available yet, the airborne SEA model is very useful to find out weak points of vehicle sound packages."
Investigation of Gravel Noise Mechanisms and Impact Noise Transfer,"Impact noise, inside a car, due to tire-launched gravel on the road can lead to loss of quality perception. Gravel noise is mainly caused by small-sized particles which are too small to be seen on the road by the driver. The investigation focuses on the identification of the mechanisms of excitation and transfer. The spatial distribution of the particles flying from a tire is determined, as well as the probable impact locations on the vehicle body-panels. Finally the relative noise contributions of the body-panels are estimated by adding the panel-to-ear transfer functions. This form of Transfer-Path-Analysis allows vehicle optimization and target setting on the level of the tires, exterior panel treatment and isolation."
Long-Range Human Body Sensing Modules with Electric Field Sensor,"The authors have developed a long range version human body sensing module. This module has a high measurement accuracy with a capacitance of less than two femto Farads and can detect more distant human bodies compared with conventional sensors. Furthermore, optimizing the electrode structure of this module, noise tolerance and directivity have been improved. We produced some prototypes of this sensor module and evaluated the sensitivity of them in a vehicle. The results show that the prototype can detect a hand at the distance of 300 mm from the sensor electrode."
A Development And Test Environment for Automotive LIN Network,"“LIN-BOX” is designed as a development tool for simulation, implementation and test of the automotive LIN (Local Interconnect Network) control devices or entire network. The tool can be used to simulate master and/or slaves around LIN system. The configurable signal processing makes it possible to simulate and test the communication behavior. LIN-BOX monitors the bus traffic in the vehicle. The data on LIN bus can not only be shown on various windows but also written into log files. LIN-BOX has been used by several cases for debugging and validation, the result shows that it is a powerful tool for LIN cluster design, simulation and test."
Study cases using the method of Statistical Energy Analyse SEA for airborne sound transmission in a vehicle body,The acoustics insulation on the car body is ones of the more important target in the NVH (Noise Vibration and Harshness) vehicle development process. The method of SEA is a validated statistical approach to solve airborne noise transmission problems. In the vehicle analysis above 300 Hz where material trim and leakage paths makes a important contribution in the vehicle interior acoustics shows the methodology its advantages over deterministic methods.
Sound Quality Engineering of a New Transport Refrigeration Unit,"The redesign of a diesel driven transport refrigeration unit is described, with focus on sound quality goals. Acoustic level and quality goals were set with customer feedback based on jury tests. Sound source levels of specific components were identified, with the noise level of the diesel intake and exhaust, the condenser fan, and noise of the gearbox having the most impact on sound quality. A post-design jury test confirmed the effectiveness of the redesign effort."
Modeling of Firewall Panel with Laminated Metal using Experiment and Numerical Methods,"For the automotive industry, the sound quality inside the vehicles is very important. This importance has increased significantly in the last years within the globally competitive automotive market. The interior vibroacoustic behavior depends on the dynamic characteristics of the car body. Several treatments are used to reduce the structural energy of the body panels. For instance, it may be applied passive damping technology, by use of viscoelastic materials, to control their noise and vibrations. This paper presents a comparison of the vibroacoustic characteristics of two firewall panels, made with normal and quiet steel. Experimental and numerical (FEM and BEM) techniques are used to get modal and acoustic data."
Scan & Listen: a simple and fast method to find sources,The particle velocity field close to a source almost matches the surface vibration whereas the sound pressure field is mainly caused by the background noise. Here a new method is proposed that is to simply listen to the particle velocity field to find sources. The method shows to give a very fast first impression of the acoustic problem at hand.
Seat/Floor Coupling CAE Study for Body/Vehicle NVH,"In today's competitive automobile environment with shorter vehicle development time and fewer prototypes/tests, CAE is becoming very crucial for vehicle development. Seat is a critical system of automobiles for customer satisfaction because seat provides support, safety, and comfort especially NVH for vehicle occupants. In this paper, the effects of seat system on body and vehicle NVH were studied. How the seat system affected body and vehicle NVH, and how seat to floor coupling affected vehicle NVH were investigated. Two groups of finite element body models, body-on-frame and unitized body, were used for this study to ensure the effect of body architecture was included in this study. In the baseline body models, the seats were represented by detailed finite element models. Then, several versions of body models were built by modeling seats in different finite element representations. Three critical vehicle road load cases (engine idle, coarse road at 30mph, and rough road at 40mph) were investigated in this study. Body NVH performance (local/global modes and seat track/floor attachment responses) and vehicle road NVH performance (front/rear interior sound and seat track/floor attachment vibration) of different body versions were assessed against that of baseline models. The conclusions would determine the seat contribution (seat/floor coupling) for body/vehicle NVH performance. The results would also guide the seat modeling methods for body/vehicle NVH CAE analysis."
NVH Optimization for Passenger Car Thermal Systems,"Noise and vibration of passenger car thermal systems are some of the major contributing factors to customer satisfaction. The optimization of these characteristics requires an integrated approach involving detailed analysis, simulation and testing. This paper describes selected noise, vibration and harshness (NVH) issues, discusses solutions and provides examples of its successful applications for thermal systems in passenger cars. The major components of a thermal system include condenser, radiator and fan module, main HVAC module, auxiliary HVAC module as well as air conditioning (AC) additional components such as lines, seals, hoses and vibration isolators. All components can contribute individually or as a system to the noise problem. Significant sound level reductions and improvements in sound quality have been achieved applying detailed analysis, Computer Aided Engineering (CAE) tools, and advanced testing methods. Examples presented in this paper include an auxiliary HVAC module of half the size and equivalent overall sound level compared to past designs, considerable reductions in objectionable noises such as aspirator and defrost bleed noises, and improvements in vibration through optimized placement of stiffening members."
Integrated Approach and Ideas for Designing Lightweight NVH Parts in Passenger Vehicle,"The Interior noise is now one of the signatures of passenger vehicles. It contributes significantly to a customer's perception of quality. The vehicle acoustic package can be an important piece to the acoustic signature, and can be used not only to reduce sound level inside the vehicle but also to shape the sound such that it meets the expectation of customer and increasing competition between the Vehicle Manufacturers. The conflicting objective of maintaining high Noise, Vibration and Harshness (NVH) characteristics at the same time reducing the weight of the vehicle is a major priority within the Automotive Industry. Moreover to meet ever-growing demand to minimize emission and to achieve greater efficiency from automobiles, there has been a constant effort to reduce the weight of the vehicle body structure along with improving NVH of vehicle. This paper reflects various measures used in the new generation automobiles to provide a superior acoustic package to the customer for a quite and pleasant drive along with improving vehicle body structure by means like bead pattern optimization and tailor rolled blank design in terms of weight reduction to give a highly efficient and greener car for creating greater customer satisfaction."
Application of Acoustic FEA to the Automotive and Aircraft Industry,Numerical simulation techniques are widely used in automotive and aircraft sectors. The optimization of industrial products with respect to acoustic performance requires appropriate modeling strategies in order to handle various noise sources and different propagation paths. The present paper focuses on the application of finite element techniques (FE) to the solution of vibro-acoustic and aero-acoustic problems. State-of-the-art FE techniques are reviewed and illustrated by appropriate examples.
Difficulties Encountered in the Correlation of Vehicle Response to Bench Testing of Driveline Gearboxes for NVH Attributes,Correlating a bench test stand to predict the response of a driveline gearbox in the vehicle can be very difficult. Many sources of variation and error may prevent correlation. This paper outlines the issues related to both vehicle and bench testing that prevents proper correlation. The importance of understanding both the NVH measurements and statistics are vital to proper interpretation. The identified issues are backed up with real test cases where these issues occurred in a series production gearbox program. A successful correlation case study is presented for comparison.
Predicting the Acoustics of Squeak and Rattle,"This paper discusses the development of a computationally efficient numerical method for predicting the acoustics of rattle events upfront in the design cycle. The method combines Finite Elements, Boundary Elements and SEA and enables the loudness of a large number of rattle events to be efficiently predicted across a broad frequency range. A low frequency random vibro-acoustic model is used in conjunction with various closed form analytical expressions in order to quickly predict impact probabilities and locations. An existing method has been extended to estimate the statistics of the contact forces across a broad frequency range. Finally, broadband acoustic radiation is predicted using standard low, mid and high frequency vibro-acoustic methods and used to estimate impact loudness. The approach is discussed and a number of validation examples are presented."
TEST EQUIPMENT MAKER'S COOPORATIVE APPROACH TO THE MEASUREMENT NEXT GENERATION AUTOMOTIVES: COMPARISON OF NOISE AND VIBRATION CHARACTERISTICS BETWEEN ICE VEHICLE AND EV,"The car's ride of electric vehicle (EV) is quite different from that of internal combustion engine(ICE)vehicle. Nonetheless, only limited discussion has held so far. We have carried out noise and vibration measurements using EV in order to compare to ICE vehicle. We have found that sound quality index in addition to sound pressure level are useful to evaluate distinguished sound of EV. Also, the characteristics of sound field in cabin are found to be quite different each other."
Improving SEA Predictions with Experimental Data,"Statistical Energy Analysis (SEA) has been used widely by industry and academia for more than 20 years to predict the mid-to-high frequency range behavior of complex acoustic systems. At Gulfstream Aerospace Corporation (GAC), SEA models have been developed to predict the interior cabin noise levels of completed Gulfstream aircraft. These models are also used for acoustic evaluations of design changes prior to implementation as well as a diagnostic tool for investigating noise and vibration issues. Throughout the development of the SEA models, extensive experimental testing in GAC's Acoustic Test Facility (ATF) was conducted on numerous aircraft components represented in the models. This paper demonstrates the importance of using experimental data to improve the accuracy of the SEA predictions by accurately adjusting the material properties and acoustic parameters of the SEA model to better match the ATF experimental data. This is particularly important for complicated SEA models with thousands of subsystems and junctions."
Prediction of Vehicle Interior Sound Pressure Distribution with SEA,"Statistical Energy Analysis (SEA) is the standard analytical tool for predicting vehicle acoustic and vibration responses at high frequencies. SEA is commonly used to obtain the interior Sound Pressure Level (SPL) due to each individual noise or vibration source and to determine the contribution to the interior noise through each dominant transfer path. This supports cascading vehicle noise and vibration targets and early evaluation of the vehicle design to effectively meet NVH targets with optimized cost and weight. A common misconception is that SEA is only capable of predicting a general average interior SPL for the entire vehicle cabin and that the differences between different locations such as driver's ear, rear passenger's ear, lower interior points, etc., in the vehicle cannot be analytically determined by an SEA model. However, because the interior acoustic energy distribution varies due to absorption and distance effects that can be modeled, an SEA model is capable of predicting the SPL at different interior locations with good accuracy at high frequencies. This paper discusses the SEA modeling assumptions used to generate a typical model of a vehicle cabin interior and surrounding structure. The distribution of acoustic absorption and its effect on the local interior SPL responses are addressed. Measurements of transfer functions to various points of the vehicle interior from exterior and interior acoustic sources and structureborne sources for a typical vehicle are presented and compared to SEA model predictions. Observations and recommendations about typical interior transfer function correlation, modeling limitations, and use of the SEA model as a design tool are given."
SEA Wind Noise Load Case for Ranking Vehicle Form Changes,"Vehicle manufacturers demand early design assessment of vehicle wind noise attribute so as to eliminate engineering waste induced by late design changes. Vehicle wind noise attribute can be simulated with a Statistical Energy Analysis (SEA) model using exterior surface turbulence pressure on the vehicle greenhouse panel as the wind noise load. One important application of SEA wind noise model is the wind noise assessment for vehicle form design. Vehicle form optimization for wind noise plays an important role in lightweight vehicle architecture, since that reduction in the wind noise load will compensate the loss of vehicle body acoustic attenuation caused by down-gauge glazing and body panels. In this paper, two SEA wind noise load cases currently used in vehicle SEA wind noise modeling have been analyzed and evaluated against vehicle measurements. Two types of evaluations have been made: prediction of the interior cabin noise level at driver's ear location and simulation of level change in the interior cabin noise corresponding to different exterior mirrors. The correlation result shows that current wind noise load cases over-predict the interior cabin noise and mis-simulate the level change in interior cabin noise in response to mirror shape change. A new SEA wind load case has been proposed. The prediction of the interior cabin noise from the proposed load case shows a good correlation with vehicle measurement. The correlation result shows that the proposed load case improves the simulation of change in the interior cabin noise in response to mirror shape change. Further effort is needed to improve the determination and representation of acoustic energy in the pseudo acoustic near field."
An Efficient Modeling Approach for Mid-frequency Trim Effects,"In traditional FE based structure-borne noise analysis, interior trims are normally modeled as lump masses in the FE structure model and acoustic specific impedance of the trim is assigned to the FE acoustics model when necessary. This simplification has proven to be effective and sufficient for low frequency analysis. However, as the frequency goes into the mid-frequency range, the elastic behavior of the trim may impose some effects on the structural and acoustic responses. The approach described in this paper is based on the structural FE and acoustic SEA coupling analysis developed by ESI, aiming to improve the modeling efficiency for a possible quick turnaround in virtual assessments. The idea is to reassemble the FE-SEA hybrid analysis results for the trimmed condition by combining radiated sound power from untrimmed body structure with trim component absorption, insertion loss data and other necessary information which can be extracted easily and quickly from an untrimmed FE model, and/or SEA model."
Reconstruction of Vibro-Acoustic Responses of a Complex Vibrating Structure Using Helmholtz Equation Least Squares,"This paper presents an experimental study on using the Helmholtz equation least squares (HELS) based nearfield acoustic holography (NAH) method for reconstructing the vibro-acoustic responses on the surfaces of arbitrarily-shaped structures. Specifically, we demonstrate the capability of HELS to reconstruct normal surface velocity (NSV) and perform panel contribution analysis. The test object is a hexagonal-shaped structure made of eight panels and frames that mimic a scaled automotive passenger compartment. The test was conducted inside a fully anechoic chamber with the structure excited by a point force using random input signals. The radiated acoustic pressures were measured via a linear array of microphones at a very close distance to the structural surfaces, and taken as the input to the HELS codes to reconstruct NSV and surface acoustic pressures (SAP). The first part of the study establishes the accuracy of the HELS reconstructions by comparing the reconstructed NSV to the benchmark NSV directly measured using a laser vibrometer. The second part is panel acoustic contribution examination (PACE) that utilizes the reconstructed NSV and SAP to determine the normal-component of the time-averaged acoustic intensity on the panel surfaces. The relative contributions from individual panels toward sound pressure level at any field point inside the compartment are determined by summing the acoustic power flow from individual panels to the field point. PACE enables one to establish the ranking of each panel for its contribution to the sound pressure level (SPL) at any field point, say, the driver ear position. The major advantage of using the HELS approach is that it can characterize the structure-borne noise on the source surface and surrounding fluid medium, as well as determine the panel contributions toward SPL values at any number of field points based on a single set of pressure measurements."
Scan and Paint for Acoustic Leakage Inside the Car,"Leakage ranking of vehicle cabin interiors is an important quality index for a car. Noise transmission through weak areas has an important role in the interior noise of a car. Nowadays the acoustic leakage inside a cabin can be measured with different techniques: Microphone array-based holography, Trasmission loss measurement, Beamforming analysis, Sound intensity P-P measurements and ultrasound waves measurements. Some advantages and limits of those measurement approaches for quantifying the acoustic performance of a car are discussed in the first part of this paper. In the second part a new method for fast leakage detection and stationary noise mapping is presented using the Microflown PU probe. This method is called Scan & Paint. The Microflown sensor can measure directly the particle velocity which in the near field is much less affected by background noise and reflection compared with normal microphones. This makes the sensor very suitable for measurements inside a complex and reactive environment like the interior of the car. A camera is used to film the sweep measurement procedure of some surfaces in the cabin interior of a Toyota Avensis. The audio data is processed and synchronized with the video data. A velocity or intensity colormap can be calculated for the different interior parts of the car under test."
Improved Noise Source Identification Using Sound Quality Metrics Mapping in Vehicle Noise Measurements,"A method of mapping a sound field using sound quality metrics has been investigated with an aim of identifying noise sources based on their sound characters rather than traditional measures such as sound pressure level (SPL) and intensity. The method having 11 metrics was implemented in four different array applications, namely near-field acoustical holography, planar beamforming, spherical beamforming, and patch acoustical holography. The sound quality metrics (SQ) mapping was applied to diesel engine measurements as well as vehicle interior measurements. In both applications, there have been a number of attempts to identify impulsive noise sources and therefore in this investigation an impulsiveness metric was developed. The proposed metric was validated against ideal impulses as a function of impulse repetition frequency, amplitude and duration of impulses. The results of noise source identification in both applications revealed that the proposed impulsiveness mapping enabled the detection of impulsive or rattling sources to be more effective compared to the use of SPL and intensity. Furthermore, a number of potential improvements on the SQ mapping are discussed."
Sensation and Measurement of Low and Very Low Frequency Time-Varying Sounds in Accordance with the Very Short Impulse Response of Low-Frequency Human Hearing,"Human hearing, with its active transducers, attention process and remarkable signal-processing abilities, challenges the transportation-product sound quality engineer to measure accordingly and has clearly given rise to the practice and tools of sound quality engineering. Transient events and/or level changes of various durations and magnitudes and over various frequency bandwidths are measurable with due care in the majority of “real-world” acoustic time-signal histories, and frequently carry subjective importance. Inspired by recent work with wind-turbine sound situations, the focus of this paper is to suggest reconsideration of some low-frequency measurement methodologies in the transportation realm. Results will be presented coherent with the hearing system's unusually short impulse response at low and very low frequencies (principal magnitude within about 10 milliseconds, slight effect to about 75 milliseconds), which make low-frequency impressions not only sensitive to time variation, but even to very short-term transitory levels. Hearing-event evaluation is strongly weighted by short-term near-peak values not revealed in overall results and largely erased in conventional constant-percentage-bandwidth measures versus time such as 1/3-octaves. This sound quality concept is generally known and applied at mid and high frequencies, but would be productive to extend to low and very low-frequency sensation and measurement."
Measuring Damping Loss Factors of High Performance LASD Coatings,"One of the most effective NVH solutions used in the automotive industry to reduce structure-borne noise is to apply vibration damping treatments to the vehicle structure. These damping treatments need to meet increasing weight reduction targets, while offering the same or better damping properties. While Liquid Applied Structural Dampers (LASD) are now delivering high damping performance at lower densities, traditional damping measuring techniques are falling short in describing the performance of these extensional layers when applied onto more realistic test samples or real structures. This paper discusses the damping performance of LASD technology, in particular the newer generations of acrylic-based waterborne LASD materials, which through improvements in polymer architecture are achieving increased damping efficiencies together with reduced density. The paper further describes a test method for evaluating the composite damping loss factor (CDLF) properties of LASD treatment layers applied to metal panels used as test samples. The panel test method is based on the calculation of the reverberation time as determined from the initial decay rate of the band filtered impulse response functions. The damping data determined by using this test method is found to be in good agreement with similar data measured independently by using power injection methods (PIM). Correlations between damping performance of LASD treatments measured by using panel testing, one dimensional beam testing, and body-in-white testing methods are also discussed. The damping measurement technique described was used as a validation tool for the latest generation, lower weight, high performance, LASD materials. Panel measurements correlate well with existing test techniques and provide useful information on damping performance, in a high modal density environment, which can be used as input into advanced NVH modeling techniques."
Damping Mass Effects on Panel Sound Transmission Loss,"The primary function of damping treatment on a vibrating panel in a vehicle is to reduce vibration levels or radiated sound power by the dissipation of energy. However, in automotive applications the mass effects of damping materials should not be ignored, especially with regard to airborne noise performance. In this paper, a Finite Element-Statistical Energy Analysis (FE-SEA) hybrid analysis is used to evaluate the mass effects of applied damping materials on Sound Transmission Loss (STL). The analysis takes into consideration effects on both the elastic properties and modal mass of the panel. It is shown that while uniformly distributing the mass of the damping material over the panel generally over-estimate the mass effects on STL, an area weighting approach underestimates the effects. Results are confirmed by laboratory testing. A nomogram is generated to show the total effect of the mass of the damping material on STL."
Simulation of Noise Reduction in Passenger Trains Using Metal Foams,"One of important problems in railway transportation systems is control of noise and vibration. Metal foams are very good medias for absorbing noise. So in this paper, noise of motion of a train is simulated by MATLAB software and the reduction of noise level in a compartment of passenger car that is equipped by metal foam sheets is considered. Commonly, the sound absorption coefficients are obtained experimentally and they are available in datasheets and references. The different parameters that influence on the capability of this equipment were considered. For example the microstructure, thickness, magnitude of compaction, relative density and etc of metal foam is effective parameters. High porosity has good effect on the performance of absorber sheet. By increasing of compaction ratio, in frequency domain we will have enhancing of absorption of the noise. Compaction process is done by two different ways: one is direct and else is progressively. Relative density has inverse relation with reduction of sound pressure level. So with these considerations the absorption ability of metal foams is less than glass wool as one of the best available noise absorbers in industry. But by changing the microstructure such as rolling, compaction and derailment and also increasing area of used metal foam, we can achieve to high level performances."
Spirit AeroSystems Acoustics Lab: Measurement and Analysis Capabilities,"Previously part of a larger OEM, Spirit AeroSystems became a standalone company 5 years ago and is currently a Tier One supplier of aerostructures. Products include fuselage components, wing structures, engine struts and nacelles, and at the request of various OEMs, fully stuffed fuselages and podded engines where all of the wiring, heating, duct work, etc. is installed prior to delivery. While operating as part of the Propulsion Structures and Systems Business Unit, the design, testing and analysis services provided by the acoustics lab potentially impact all programs at all stages of development because of increasing noise regulations and material certification requirements for implementation in high noise environments. In order to address these issues, the acoustics lab has three main objectives: support design and development of engine nacelle lining technologies, ensure components meet structural fatigue requirements and ensure aircraft interiors meet noise regulation exposure limits. Historically, the primary focus of the lab has been the development and testing of acoustic liners and their components and qualification of assemblies and materials that will be exposed to high level noise environments. One objective of this paper will be to discuss the methods used to design, develop, and verify the performance of an acoustic liner and the structural integrity of not only the acoustic liners but any assembly or material installed in a high level noise environment. A second objective will be to discuss the development of new testing and analysis capabilities that arose from the relatively recent requirement to address structural acoustic and interior noise requirements."
A Pragmatic Approach to Production NVH Test of Seat Adjusters,"A powered seat adjuster is a complex mass-produced assembly that is heavily optimized for low cost and light weight. The consequence is an inevitable degree of uncontrolled variation in components, subassemblies, and final product. Automakers are driving an exceptional focus on quality and the showroom experience of the car buyer is paramount. Therefore, any seat adjuster with the potential to not satisfy the customer's expectation is likely to be screened on the production line. This paper describes NVH metric design in the context of automated production line detection of seat adjuster defects. A key requirement of the production environment is that the metrics offer intuitive explanations of possible defects and are based on industry-standard formulations. The metric set is a hybrid of objective and subjective parameters with a focus on ensuring a robust sorting process that maximizes detection while minimizing the possibility of failing acceptable product. As a set, the metrics are therefore capable of correlation to human subjective impression of the seat track sound as well as direct indication of specific defects that may fail one or more objective metrics."
Practical Considerations of Driveline Vibration and Acoustic Test Cell with Case Study of McLaren's Driveline Dynamometers,"Test Facilities for Vibrations and Acoustics can be very complicated. With the addition of necessary high power motor dynamometers for load application, the complexity of the test cell increases dramatically. The motors and subsequent additional fixtures and shafts necessary to apply loading conditions can produce additional source noises that would interfere with test measurements. In addition, facility interfaces can dramatically influence the test cell setup and reduce the measurement capabilities. This paper addresses common considerations needed in considering a new test cell for driveline vibration, acoustics, efficiency, and durability testing using motored dynamometers. In addition to outlining common design points, a practical application of 2 new dynamometers utilized for vibration, acoustics, efficiency, and durability testing and their subsequent capabilities are outlined."
VALIDATE - Basis for New Sophisticated Research Platform for Virtual Development of Vehicle Systems,"The Stuttgart Driving Simulator currently under construction at the University of Stuttgart makes out the main component of the University's new automotive research platform. The facility will be one of the largest of its kind in Europe. The simulator is based on a powerful eight axes motion system to realistically recreate the linear and rotary motion as perceived by the driver during a real trip. To add further value to the driving simulator, it is designed to house a real vehicle which can be easily exchanged - from small passenger cars up to large luxury sedan vehicles as well as SUVs. To assure a sound testing environment, the driving simulator features a realistic graphical and acoustic representation of the vehicle environment such as roadway, environment, and traffic. This is achieved through a complex surround visualization system with very high level of detail as well as an advanced spatial acoustic noise generator. Additional to this, high-quality dynamic force feedback systems at the control elements (pedals, steering wheel, gear stick, etc.) ensures a realistic vehicle and driver milieu. The research platform currently set up is predominantly specialized for energetic topics within the automotive research and development and hence well suited for contemporary topics like sustainable mobility. A major research topic will cover the field of driver influences. With the measurement vehicle, as a further component of the research platform, a first, for German conditions representative study, has been conducted. The acquisition of the driving resistances and power flows in IC, the onboard electrical system, auxiliaries, exhaust system, and cooling system during real drives confirms the strong influence of the driver on the fuel consumption and thus the CO₂ emissions. On average, the driver accounts for a 6.5% fuel consumption variation and in a standard situation variations in fuel consumption up to 65% due to driving style have been measured. Based on the knowledge about the saving potential in various driving situations, appropriate assistance systems can be designed and qualitatively and quantitatively tested and verified in the new driving simulator environment."
Optimum Constraint Strategy for Liftgates,"The present study defines the functional requirements for a liftgate and the body in order to avoid rattle, squeak, and other objectionable noises. A Design For Six Sigma (DFSS) methodology was used to study the impact of various constraint components such as bumpers, wedges, and isolated strikers on functional requirements. These functional requirements include liftgate frequency, acoustic cavity frequency, and the stiffness of the liftgate body opening. It has been determined that the method of constraining the gate relative to the body opening has a strong correlation to the noise generated. The recommended functional performance targets and constraint component selection have been confirmed by actual testing on a vehicle. Recommendations for future liftgate design will be presented."
Experimental Analysis of the Filter Element Influence in A/C System,"The study objective is to evaluate the thermal comfort and vehicle safety emphasizing on air-conditioning system. Several aspects of automobiles thermal comfort are associated with security issues as the windows defogging and defrosting, and air quality inside the vehicle. For the automotive industry, constant air flow in the vehicle is the reason of continuous research on the improvement of the stream and quality of the air that reaches the occupants. This work presents flow bench and vehicle experimental tests results ass an evaluation of the possibilities of the filter element improvement, for the flow, air filtering and temperature adjustment optimization inside the vehicle. Comfort and safety evaluations were made by the air stream inside the vehicle and experimental tests in a climatic chamber. All the tests were made in the same vehicle. Local head losses were evaluated at the flow bench and the vehicle conditioning at the climatic chamber. The pressure inside the vehicle was analyzed during the flow variation, to ensure a comfortable condition for vehicle occupants."
Door Latch Strength in a Car Body Environment,"Federal Motor Safety Standard (FMVSS) 206 regulates the minimum strength of side door latches in passenger carrying vehicles. The purpose of the standard's requirements is “to reduce the likelihood of occupants being ejected from vehicles in real world accidents.” Investigation of unwanted door openings during accidents has revealed various types of latch failures that do not produce latch and/or striker damage consistent with that found in Federal Motor Vehicle Safety Standard compliance testing. An intersection collision in which a striking vehicle contacts the struck vehicle aft of the affected door has for many years been considered the “most critical to door latch performance” (1). This type of car to car collision will often result in structural separation of the door end panel, “B” post striker panel or latch/striker assembly. These structural failures combine tensile and shear loading on the latch/striker assembly. This paper defines the state of the industry with regard to vehicle door latch strength using a simple testing method that produces door latch separations more consistent with common intersection side impact collisions. The test methodology simultaneously applies both longitudinal and lateral loads as the vector sum of the FMVSS 206 defined loads. To place the test findings in perspective, results are normalized using the existing 206 requirements."
Development of Cabin Air Quality System,"In recent years, concern among car users regarding air quality has been steadily increasing. Pollen and diesel vehicle exhaust gases entering the cabin and smoke from fellow passengers not only reduce the quality of experience for everyone in the car, but are also harmful to the health. Therefore, we developed: 1 A low pressure loss, dust-removing, selectively deodorizing filter that effectively absorbs malodor from diesel vehicle exhaust gas, without affecting A/C performance. 2 An automatic intake door control system that excludes outside exhaust gas 3 An optic catalytic air purifier with germ removal and long life deodorizing functions. We here report on the system combining these functions."
Effects of Vehicle A-pillar Shape on Local Mean and Time-Varying Flow Properties,"Separated flow is the main generator of aerodynamic noise in passenger vehicles. The flow around the A-pillar is central to the wind noise as many modern vehicles still have high fluctuating pressures due to flow separations in this region. Current production vehicle geometry is restricted due to the amount of three dimensionality possible in laminated windscreen glass (and door opening etc). New materials (e.g., polycarbonate) offer the possibility of more streamlined shapes which allow less or no flow separation. Therefore, a series of experimental investigations have been conducted to study the effects of the A-pillar and windshield geometry and yaw angles on the local flow and noise using a group of idealised road vehicle models. Surface mean and fluctuating pressures were measured on the side window in the A-pillar regions of all models at different Reynolds numbers and yaw angles. Flow visualisation was also used to see the flow structure and supplement the surface mean and fluctuating pressure data. Frequency based analysis was conducted. The studies show that depending upon the curvatures of A-pillar and windshield, the fluctuating pressure coefficients can be reduced significantly. Reynolds number sensitivities were minimal and the surface mean and fluctuating pressures can be scaled if no feedback mechanism is present. A relationship between the surface fluctuating pressure coefficients and local A-pillar radii was established."
System Design Parameters in Determining Automotive Sidelite Glazing Performance,"A study has been conducted to develop design criteria for materials for use in glazing systems and to identify the parameters affecting actual intrusion-resistance. The intent is to be able to provide the automotive consumer with enhancements in occupant security and safety through incorporation of enhanced protective glass (EPG) in body glass locations. Based on actual sidelite attacks and measurements of human applied forces, an appropriate and comprehensive test methodology has been developed. The test method extends beyond simple impact by providing a measure of the applied force or energy to gain entry to the vehicle through the sidelite as installed in a vehicle. Tests have revealed that the performance level depends not only on the particular glazing type utilized, but how it engages with the door system which in turn controls the in-service performance. Information generated by this methodology has compared favorably with time-to-vehicle-entry obtained from direct human attack. This type of comprehensive testing has provided valuable information for guiding glazing development and outlining parameters for proper design of door systems. The sidelite testing and product evaluation has also provided insight into factors which relate to occupant interaction and safety when occupant contact with body glass occurs. Many of the relationships overlap between occupant security and safety, such that, if a reasonable degree of intrusion-resistance is provided, there will be a commensurate benefit in occupant safety (c.f., ejection-mitigation)."
ISS Crew Refrigerator Freezer Rack - Comparing EcosimPro and ESATAN Modeling,"The Crew Refrigerator/Freezer Racks (RFR) are being developed and built at Astrium Friedrichshafen under ESA contract. The RFR will provide conditioned storage volume for astronaut food during transport in the MPLM and on board the ISS. To support the design of the RFR a thermal model has been established at Astrium in the early project phase using the ESATAN software which is the ESA standard thermal analysis tool. This model has been extended to allow full operational simulation of the RFR during a typical mission scenario. For demonstrating the capabilities of EcosimPro, a state of the art tool to address Environmental Control and Life Support analysis, the same model is built up with EcosimPro. The results are validated by comparing them to those from the ESATAN simulation. Three simulation cases are investigated: steady state operation mode, 8 hours passive period with increase of ambient temperature from 30°C to 49°C and recovery, door opening every 3 hours for up to 30 seconds at ambient temperature of 30°C."
“A Dry Aircraft is a Safer Aircraft – Beating Condensation by Using Dry Air”,"The airline industry seems to be providing more leisure features on planes like inflight entertainment, Internet access and Digital TV, but it seems the airline industry has ignored the issue of excess condensation on aircraft, which had plagued carriers since the birth of the airline industry. How safe are passengers when a wide body aircraft carries in excess almost a half ton of water and ice between the cabin and skin of the aircraft? Besides the added weight straining the aircraft, excess condensation soaks wires and connectors which can cause electrical shorts. There have been instances of emergency doors frozen shut, locked by ice stemming from excess water dripping inside the plane. Extra water also causes “rain-in-the-plane”, an issue that has gained national attention and causes passenger discomfort. It's time for the industry to address what has become a serious issue. With decision makers searching for an answer on how they can ensure their passengers' safety, one way is to prevent excess condensation in aircraft. Up until now, solutions were expensive, temporary and vacuous. CTT has taken the lead in addressing these problems and understanding the root causes. They have developed technology to which addresses these problems economically and permanently. With commercial airlines searching for the answer, CTT can present strategies to prevent these problems and help airline executives keep their passengers as safe as possible. The speaker is the CEO of CTT Systems. The company developed a system that solves the condensation by using dry air."
Peugeot Fractal demonstrates a new take on sound design,"Peugeot used the 2010 SR1 concept to introduce its i-Cockpit touchscreen-based system, designed to control heating and ventilation, navigation, audio, connectivity, and the trip computer. The first-gen system entered production in the 2012 Peugeot 208. The company took the i-Cockpit concept one stage further in the Fractal electric urban coupe concept at the 2015 IAA Frankfurt Show, to include sound. The concept plays a “sound signature,” created by DJ and sound designer Amon Tobin, which is triggered when the driver opens the car using the smart watch remote locking system. “Behind this concept of an electric car-that is not really new, there was this question that electric cars emit no sound,” explained Matthias Hossann, Head of Concept Cars and Advanced Design at Peugeot."
"Momentum, the Magazine for Student Members of SAE International 2010-09-01","High-speed education @ formula hybrid event Annual competition provides a hands-on learning experience for undergraduate and graduate engineering students. Body-shaped for supermileage Six different single-occupant vehicles designed and built by teams of collegiate engineering students snared four-digit fuel economy at Eaton Corp.'s Marshall, MI, test track during the 31st annual SAE Supermileage competition in June. Mercedes-AMG goes with the current flow Opening the doors on new technology. First flight approaches for 'disruptive' new UAV engine An earlier iteration of UAS' Nightwind 2 in flight, powered by an off-the-shelf industrial engine. Three resume tips for college grads Employers often hire recent graduates to mold new hires to their own corporate culture and work philosophy, leading some employers to look more for potential than for specific experience. SAE, Deere announce 'learn twice' initiative Students involved in SAE International's Collegiate Design Series can get their team's registration fee reimbursed by working with local elementary and high school teachers to teach science, technology, engineering, and math concepts through the ""A World In Motion"" curriculum. EngineerXChange being launched to help attract younger members With the launch of EngineerXchange in October, SAE is hoping to communicate with young engineers via the Web and social media."
Automotive Engineering: March 2021,"Engineering Ford's future Product platform and operations chief Hau Thai-Tang on navigating the microchip shortage, compact-unibody trucks, EV and AV challenges, and driving engineering efficiencies amid the lockdown. NAWA aims for 5-minute EV charge A new nano-based carbon electrode is key to reducing electric-vehicle charging time. Hemphill's mission: Support the innovation ecosystem Schaeffler America CTO Jeff Hemphill brings impressive technical chops and well-honed communication skills to his new role as 2021 SAE International president. Editorial The legacy of the pioneering, controversial EV-1 SAE Standards News Help wanted: SAE tech standards committee, task force seeks new members SUPPLIER EYE Electrification and the Two-Cycle Imperative Electrified Corvettes in development German OEMs flex 3D manufacturing muscle ZF builds 'middleware' to address vehicle software escalation TDK unveils power-generating wheel sensor Bosch consolidates computing talent in new mobility division Ford F-150 Raptor goes 4-door only; R version next year Q&A Celina Mikolajczak, VP of battery technology for Panasonic Energy of North America, discusses The relentless pace of EV battery development and manufacturing"
"Momentum, the Magazine for Student Members of SAE International 2012-10-31","The Nano in retrospect A senior graduate student in the Department of Mechanical Engineering at the Indian Institute of Technology looks at the development of the world's cheapest car and its effect on Indian car users. A different riff on your basic two-seat electric car Markus Lienkamp, Chair of Automotive Engineering at the Technical University of Munich, is leading the Visio.M project, a German government-supported R&D effort to produce a low-cost, high-utility electric car that might attract the interest of the middle European mass market. Materials lead the way to vehicle mass reduction Reducing a vehicle's mass opens the door for a downsized engine and transmission, a lighter cradle and body structure, smaller wheels and brakes, as well as a weight-slimmed suspension. The start point for this ripple effect is materials."
Momentum: October 2014,"Buckeye Current's TT triumph The Ohio State University reprised its third-place finish in the 2014 TT Zero for all-electric motorcycles, beating some of the pros on the world's toughest race circuit. Kettering FSAE team improved as season progressed Lowest priced may not mean the best, but certainly not the worst. Leveling the field: getting #girlsinstem Despite facing the brunt of gender segregation, women are forging ahead and dramatically improving STE M, both academically and professionally. Mercedes-AMG's SLS departure opens door to new GT Powering the car is an all-new biturbo 4.0-L V8 available with two power levels: hot (GT) at 340 kW (456 hp) and exceedingly hot (GTS) at 375 kW (503 hp)."
Analytical and Experimental Approach to Acoustic Package Design,"The interior noise signature of passenger vehicles is a significant contributor to a customer's perception of quality. The vehicle acoustic package can be an important piece to the acoustic signature, and can be utilized not just to reduce the sound levels inside the vehicle but also to shape the sound such that it meets the expectations of the customer. For this reason the definition, design, and development of an acoustic package can be vital to meeting vehicle-level acoustic targets. In many situations this development is conducted experimentally, requiring the availability of prototype vehicles and acoustic package components. Of more value is the ability to develop components early in the design phase, leveraging analytical tools to define component-level requirements and targets to meet the vehicle-level targets, and ultimately meet the final customer expectations. This paper presents efforts made to further combine the benefits of experimental and analytical approaches to acoustic package design. The benefits of which include the ability to predict interior sound levels for alternative acoustic package configurations early in the design phase, allowing for listening studies to verify component and vehicle-level targets. Additionally, the performance of alternative designs can be quantified in the frequency domain and using sound quality metrics, while minimizing the necessity for physical testing. A current market vehicle was utilized for this development, in which experimental measurements were developed and conducted for optimum cooperation and utilization of analytical tools. The acoustic package was characterized to predict the sound levels for alternate acoustic package designs, listening studies were performed and metrics were calculated for each configuration to verify performance against the vehicle-levels targets, and developed solutions were verified through experimental testing."
A CFD/SEA Approach for Prediction of Vehicle Interior Noise due to Wind Noise,"For most car manufacturers, aerodynamic noise is becoming the dominant high frequency noise source (> 500 Hz) at highway speeds. Design optimization and early detection of issues related to aeroacoustics remain mainly an experimental art implying high cost prototypes, expensive wind tunnel sessions, and potentially late design changes. To reduce the associated costs as well as development times, there is strong motivation for the development of a reliable numerical prediction capability. The goal of this paper is to present a computational approach developed to predict the greenhouse windnoise contribution to the interior noise heard by the vehicle passengers. This method is based on coupling an unsteady Computational Fluid Dynamics (CFD) solver for the windnoise excitation to a Statistical Energy Analysis (SEA) solver for the structural acoustic behavior. The basic strategy is to convert the time-domain pressure signals generated by CFD everywhere on the panels into structural power inputs, which in turn are used as input to an SEA model leading to the noise inside the cabin. This approach quantifies the windnoise contribution coming from different panels (e.g. side windows, windshield) at various locations inside the vehicle (driver and passenger headspace). In this paper the key technical and numerical aspects of the approach are presented, and interior noise predictions corresponding to real automotive cases are compared to experimental measurements. As examples of the usage, a vehicle exterior shape design study and an acoustic package optimization study are presented."
A Systematic and Disciplined Process for Developing Drive Files for Squeak and Rattle and Durability Tests in the Lab,"The pressure to shorten vehicle product development time-to-launch means more in-lab tests must be performed earlier, and before vehicle prototypes are available for road or test track evaluations. Squeak and Rattle (S&R) evaluations of subsystems/modules and components must be performed using realistic road excitation conditions. How S&R performance degrades as the vehicle, module or component accumulates customer miles or kilometers must be assessed before the design is frozen. Durability tests must be performed earlier in the design/development timeline as well. All these pressures point to having a systematic, disciplined and streamlined methodology or protocol for acquiring and processing road vibration data useful for S&R and durability tests. The protocol must comprehend data acquisition, sampling, and signal processing; properly editing acceleration time histories for either in-lab replication as time histories or as PSD random vibration; creation of drive files that replicate multiple road surfaces; combining multiple road surfaces and speeds into fewer (if not one) tests that replace one-test-for-one-road-condition approaches; selecting overall vibration amplitudes for composite multiple roads; and performing such tests in order to satisfy S&R and durability experts, design/release engineers seeking design validation, and multiple other stakeholders. This paper presents such a protocol based on the expertise from different engineers working on a multitude of vehicle development programs from different companies in different countries over many years."
A Generic Model for Analysis and Optimization of Fuel Filler Door with Torsional Spring,"A mathematical model was developed for the analysis of a fuel filler door with a torsional spring. The model calculates performance indices such as opening and closing forces, kinetic energy during opening and closing and the maximum spring stress. The model was integrated with an optimization program. Two types of optimization problems were formulated: the traditional problem which does not include the effects of random design parameters, and the stochastic type optimization, which does. An example shows how the mathematical model, in conjunction with optimization techniques, can help determine fuel filler door designs."
Modelling the Dissipative Effect of Seal Air Hole Spacing and Size on Door Closing Effort,"Door weather strip seals are designed with ventilation holes spaced at regular intervals along the seal system to expedite the flow of air from the seal system during the door closing process. The flow of air through the ventilation holes represents a nonlinear damping mechanism which, depending upon hole size and spacing, can significantly contribute to door closing effort. In this study we develop one- and two- dimensional versions of a nonlinear damping model for seal compression load deflection (CLD) behavior which incorporate the effects of seal damping response due to air flow through the ventilation holes. The air flow/damping models are developed from first physical principles by application of the mass and momentum balance equations to a control volume of entrapped air between consecutive air ventilation holes in the seal system. Both model formulations indicate that the damping component of seal force per unit length generated during seal compression is directly proportional to , where L and D represent, respectively, the spacing distance and diameter of the air ventilation holes. Numerical predictions for the damping force at a section in a production vehicle door seal system during closing are made using the two models and results compared."
Door Structural Slam Durability Inertia Relief Approach,"The automotive industry faces many competitive challenges including weight and cost reduction to meet CAFE standards. In particular, a thin door panel optimized for weight reduction can cause high manufacturer warranties and durability problems. Traditionally, the assessment of door slam durability is accomplished by tests rather than using computer aided techniques. Many simple CAE techniques such as simple linear static and dynamic analyses have been used to evaluate the door structural integrity. However, the door slam event requires complex analysis due to the transient impact phenomenon. To solve this complex door slam event with a computer based technique is a challenging and interesting problem for CAE engineers. However, a simplified technique has been developed to anticipate the potential durability problem in the door. This technique involves the use of the computer- based finite element method incorporating inertia relief and fatigue life prediction. Actual testing validated the analytically predicted results. This method provides an inexpensive way of predicting door slam durability reducing development time and product cost. As a result, the new approach aided the door design robustness."
Research on the Application of Aluminum Door Beams for Automobiles,"The effect of cross-section and type of alloy on the performance of aluminum extrusions as door beams was investigated. As a result, aluminum door beams were developed which have bending properties comparing favorably with those of door beams made of high tensile strength steel with a tensile strength of 1470 N/mm2. Furthermore, a technology to design door beams with the required performance and bending properties dealing with various car models was developed by making the most of the versatility of aluminum extrusions produced in various types of cross-sections."
Response of the Eurosid-1 Thorax to Lateral Impact,"The Eurosid-1 dummy was subjected to a series of lateral and oblique pendulum impacts to study the anomalous “flat-top” thorax deflection versus time-histories observed in full-scale vehicle tests. The standard Eurosid-1, as well as two different modified versions of the dummy, were impacted at 6 different angles from -15 to +20 degrees (0 degrees is pure lateral) in the horizontal plane. The flat-top deflections were observed in the tests with the standard Eurosid-1, while one of the modified versions reduced the flat-top considerably. Full scale vehicle tests with the standard and modified Eurosid-1 suggest similar reductions. A second series of tests was conducted on the modified Eurosid-1 to investigate the effect of door surface friction on the shoulder rotation and the chest deflection. The data suggested that increasing the friction on the door surface impeded shoulder rotation and ultimately reduced the chest deflection in the Eurosid-1."
An Investigation of Vehicle HVAC Cabin Noise,"Noise and vibration have an important influence on a customer's perception of vehicle quality and cabin interior noise levels are a key criteria. The interior sound levels of automobiles have been significantly reduced over the years, with reductions in power train, tire and external wind noise. One of the highest in-cabin noise levels now arises from heating, ventilating and air conditioning systems, generated by the air-rush noise at various HVAC settings. Thus quieter climate control systems are desired by car manufacturers. A systematic benchmarking study was performed to investigate the in-cabin noise of vehicles. 21 passenger cars including compact, mid-size, full-size, and a truck were selected. Tests were conducted on relatively new production vehicles in various conditions. A binaural head system was used in front passenger seat to measure noise levels. The methodology used and the experimental results were presented in this paper. It was found that the design of the HVAC system has a major influence on the vehicle in-cabin acoustic performance. The size/price of the vehicle may not correlate to the cabin quietness due to the complexity of acoustic effects in the HVAC system."
Class A Application/Definition,"This SAE Information Report will explain the differences between Class A, B, and C networks and clarify through examples, the differences in applications. Special attention will be given to a listing of functions that could be attached to a Class A communications network."
Investigation on Wiping Noises and NVH Design Consideration in a Wiper System,"As automobiles become increasingly quieter, the wiper operation noise becomes more noticeable by the customer. This paper deals with the experimental approach and the methodology to investigate the Friction induced wiping noise. Role of design in a wiper system plays a very imperative task in meeting the performance of wipers but at the same time it does not cater to the NVH issues. Some of the important design parameters which affect the NVH properties of the wiper system are highlighted in this paper. For better understanding of the system some of the best in class vehicles for SUV category were tested and compared with our test vehicle. In this study more importance given to analytical part which is more important to investigate and in depth study of the friction induced noise. For analytical study some techniques such as time frequency domain i.e. Wavelet transforms, frequency domain and time domain where extensively used. Finally ranking of the NVH design factors based on the criticality are stated in this document. These factors may be helpful during design of wiper system for better NVH, without deteriorating the functional performance."
Sound Absorbers in Small Cavities,"The automotive industry is often interested in controlling noise radiated from trim pieces in the passenger cabin. In general, there is a small air gap that separates these trim pieces from the sheet metal that is the actual source of the noise. It is common practice to place an acoustically absorbent material in this space to reduce radiated noise. In this paper the in situ noise control performance of a variety of materials is examined by placing them in a test fixture that simulates the sound field in the vicinity of vehicle pillar trim. In this fixture a noise source is positioned behind a piece of sheet metal. A flat plastic sheet that is similar in composition to pillar trim is placed a small distance away from the sheet metal. The sides and rear of the fixture are sealed so that the plastic sheet is the only significant radiator of the sound radiated from the sheet metal. The random incidence and normal incidence performance of a variety of absorbers are compared to their performance in this test fixture. In addition, the theory that relates the acoustic absorption of a material to its ability to decrease noise levels will be considered."
Application of an Elastomeric Tuned Mass Damper for Booming Noise on an Off-highway Machine,"NVH is gaining importance in the quality perception of off-highway machine performance and operator comfort. Booming noise, a low frequency NVH phenomenon, can be a significant sound issue in an off-highway machine. In order to increase operator comfort by decreasing the noise levels and noise annoyance, a tuned mass damper (TMD) was added to the resonating panel to suppress the booming. Operational deflection shapes (ODS) and experimental modal analysis (EMA) were performed to identify the resonating panels, a damper was tuned in the lab and on the machine to the specific frequency, machine operational tests were carried out to verify the effectiveness of the damper to deal with booming noise."
A New Modeling Technique of Large Trim Part Air Passages for An Accurate Acoustic Model,"Finite element models based on the design drawing information are widely applied in the early development stage in the automotive industry. During this stage, the performances of noise and vibration of a vehicle are evaluated by the calculation using FE models. Therefore, it is extremely important to secure the accuracy of the calculation by FE models. Otherwise the problem does not solved with the countermeasures implemented in FE models. To predict sound pressure levels in the passenger compartment, an acoustic model for the compartment must be precisely created. Experimental analysis have shown in the past that narrow air gaps between interior trim parts or between a trim part and a body structure have a high impact on the acoustic transfer functions even in the low frequency range where the issues on booming noise and road noise are often addressed. However, the narrow gaps are usually not modeled in FE models because a lot of small finite elements are needed to express the narrow gaps and much resource is required for the calculation. In this study an acoustic leakage element is proposed to model the narrow air gaps. This element consists of one hexahedral element representing air gaps and several rigid elements connecting adjacent acoustic fields. Specifications for the hexahedral element are experimentally identified by using Helmholtz resonator. The proposed method is verified by the comparisons between the measured and calculated acoustic transfer functions of a vehicle."
Brake Grind Noise Reduction Potential on Vehicle Level - A TPA Study,"Rust accumulated on disc rotor surfaces causes brake judder and excessive grind noise. This low frequency noise phenomenon is audible especially at low vehicle speed without masking from other noise sources like wind and road noise or power train sound. This often leads to customer complaints resulting in significant warranty costs. Alternative drive systems like hybrid or full electric power trains will emphasize this problem. Most studies concentrate on optimization of the brake system to reduce low frequency brake noise. In this work, the potential for optimization on vehicle level was investigated. The most effective NVH optimization can be achieved by improving and matching the acoustic properties of the vehicle and the brake system. In a first step, the main structure borne noise transfer paths have been identified by means of Transfer Path Analysis. A detailed analysis of the relevant transfer paths shows critical sound transmission of the suspension system and its attachments to the vehicle body. The potential of this approach for brake noise optimization is demonstrated by an example. As a second step, the radiating body surfaces contributing to the perceived brake noise have been identified using panel contribution analysis. This helps to optimize the vehicle body structure and trim package. The potential for improvements has been predicted using a modified interior noise synthesis model. The results have been verified experimentally by principal modifications to the vehicle."
Operational Modal Analysis Techniques used for Global Modes Identification of Vehicle Body Excited from a Vehicle in Idle Engine,"With the purpose to identify the root cause of increased levels of vibration felt at idle speed in a popular vehicle prototype a study was conducted using techniques for analysis of vibration transmission between components of a vehicle, using Mechanical Vibrations Analysis and Operational Modal Analysis, for the analysis of the operational modes was used ODS - Operational Deflection Shape technique which is possible only see the shapes related to probable modes. The experimental results were compared with results for the modal analysis by Finite Element Method (FEM). The vehicles used are identical prototypes, but with different levels of vibration. Therefore, to study there is a vehicle with satisfactory levels and a second with unsatisfactory levels. This study demonstrates the methodology used to identify the cause of the different behaviors between cars and also discuss the improvements made in the body according to the results of the numerical experimental confrontation."
CHARACTERISATION OF PASSENGER VEHICLE IN-CABIN NOISE USING OMA AND SOUND QUALITY TECHNIQUES - AN INTEGRATED APPROACH,"In the recent past, interior noise quality has developed into a decisive aspect for the evaluation of overall vehicle quality. The paper discusses the effect of structural modes of vibration caused in a passenger car during its operational conditions and its effect of noise inside the cabin. In order to characterize the body modes under road operation, OMA is used and the Interior noise quality of car cabin is judged by the Sound quality tools. Based on the jury evaluation, the problem is identified and problem area is identified with operational modal analysis techniques to take the countermeasure and verification of the study is done. The relation of body modes is established to overall cabin noise performance and improvements are checked with use of Modification Prediction tool after identifying the critical areas. This study is helpful in developing the new vehicle modal faster and also to analyze and to take countermeasure at earlier stages of developments."
Acoustic-Structural Sensitivity Analysis and Optimism of Car Body Multilayer Panels,"Acoustic-structural sensitivity analysis for coupled acoustic-structural systems can be conveniently and quickly used in dynamic modifications of car body panels to reduce interior sound pressure level. In practice, car body panels are multilayered structure which consists of the outside skin, the interior trim, and the air gap or absorbent layer between them. The vibration characteristics and the capability of sound insulation of multilayer panels are very important factors which dominate acoustic response in car cavity. A simplified car body model is made to investigate the effects of multilayer panels on interior sound levels. With the model, the relation between the acoustic response of the cavity and the property of multilayer panels are achieved. The validity of theoretical analysis is verified through a comparison between the experiment and the numerical simulation results. Finally, acoustic-structural sensitivity analysis of car body multilayer panels is evaluated synthetically. The panels’ structure is optimized, and car interior sound level is improved."
Modeling Airborne Noise Transmission in a Truck using Statistical Energy Analysis,"Statistical Energy Analysis (SEA) was used during the design of a new heavy duty truck. This paper provides an overview of the building and validation process of an airborne SEA model of a typical commercial vehicle. Predictions of interior noise levels are compared against tests. A noise path contribution analysis is presented, demonstrating how the impact of potential design changes on the interior sound levels can be evaluated with an SEA model."
Vehicle Airborne Noise Analysis Using Boundary Element and Finite Element Energy Based Methods,"The Energy Finite Element Analysis (EFEA) has been developed for computing the structural vibration and the interior noise level of complex structural-acoustic systems by solving governing differential equations with energy densities as primary variables. A finite element approach is employed for the numerical solution of the governing differential equations. Results from EFEA simulations have been compared successfully with test results for Naval, automotive, and aircraft structures. The Energy Boundary Element Analysis (EBEA) has been developed for conducting exterior acoustic simulations using the acoustic energy density as primary variable in the formulation. EBEA results have been compared successfully to the test results in the past for predicting the exterior acoustic field around a vehicle structure due to external noise sources. In this paper, the EBEA and EFEA methods are combined for predicting the interior noise levels in a vehicle due to exterior acoustic sources. The EBEA is employed for computing the acoustic field around a vehicle structure due to exterior acoustic noise sources (i.e. tire source, engine source, etc.). The computed exterior acoustic field comprises the excitation for the EFEA analysis. The vehicle structure, the acoustic treatment, and the interior acoustic volumes are represented in the EFEA model. The interior noise level in the vehicle is computed by the EFEA. Predictions for the interior noise level (expressed in a noise reduction format) are compared favorably with test results for two separate types of excitation. A generic case study is presented for computing the interior noise due to exterior acoustic excitation from a transmission and a driveline."
Acoustics Inside the Space Shuttle Orbiter and the International Space Station,"The acoustics environment in enclosed habitable space vehicles and modules is important to mission safety, crew health, and efficient operations. Noise is unwanted sound that can interfere with crew communications and sleep, creating habitability concerns, hearing loss, or other health issues. This paper discusses the acoustic environment and the noise control efforts in the Space Shuttle Orbiter and the International Space Station, and the lessons learned from these efforts. Included is the need to apply the design discipline of acoustics early in the design process, to establish reasonable acoustic limits and “design them into” vehicles/modules, and to apply noise control to ensure that limits are met. Program management needs to be supportive of these efforts."
Optimization of Sound Packages for Commercial Vehicles Using Panel Contribution Analysis,"Microphone array-based Panel Contribution Analysis (PCA) is a new technique used for Sound Package design optimization for commercial vehicles. The technique allows for noise control performance and cost optimization. This technique ranks the contribution of fully trimmed structural panels (e.g. floor, roof, etc.) and leaks in a vehicle cabin to the noise levels experienced by a driver while the vehicle is in cruising operation. Often the noise and vibration sources (engine, transmission, exhaust, aerodynamic noise, tires, etc) cannot be easily modified, thus the only practical action to solve noise problems is to design the noise control treatments applied to the vehicle panels. Panels that have a large contribution to the noise levels at the driver's ear are heavily treated with noise control materials, whereas panels with low contribution get little to no treatment. This paper describes a microphone array-based PCA technique, and the results of a successful application of it to optimize the interior noise level performance of a new commercial vehicle. The application results clearly indicated the dominant contributing panels to the sound pressure levels at the driver's ear."
A PU Probe Array Based Panel Noise Contribution Analysis Whilst Driving,"This paper presents new developments on hot wire anemometer based panel noise contribution analysis. The used sensor allows the direct measurement of particle velocity. Some historical remarks are given and the latest developments of the technique are reported. Four steps are required to determine the panel noise contribution of the interior of a vehicle and to visualize the results in 3D. In a first step the probes are positioned on the interior surfaces and their x, y, z coordinates are measured. Based on these data a 3D geometry model is created. The geometry data are acquired using a specially designed 3D digitizer. The second step is a measurement in a certain mode of operation. This step can be done in a laboratory but it is also possible to perform the measurement whilst driving the vehicle on the road. Stationary as well as non stationary running conditions like e.g. run ups are accessible and do not limit the applicability of the method. The third step is the determination of the transfer paths from the panels to a certain listening position. This measurement is done reciprocally. In a fourth and last step the transfer paths are linked with the operational data gathered in step two. The results are then visualized using the 3D geometry model. This paper describes the measurement of a conventional car with a resolution of 180 panels. Since an array of 45 probes was used step 2 and step 3 had to be repeated 4 times. The complete measurement typically takes approximately 3 days."
Mapping 3D Sound Intensity Streamlines in a Car Interior,"Sound source localization techniques in a car interior are hampered by the fact that the cavity usually is governed by a high number of (in)coherent sources and reflections. In the acoustic near field, particle velocity based intensity probes have been demonstrated to be not susceptible to these reflections allowing the individual panel contributions of these (in)coherent sources to be accurately determined. In the acoustic far field (spherical) beam forming techniques have been used outdoors in the free field, which analyze the directional resolution of a sound field incident on the array. Recently these techniques have also been applied inside cars, assuming that sound travels in a straight path from the source to the receivers. However, there is quite some evidence that sound waves do not travel in a straight line. The Maritime Institute of Stetting in Poland made numerous 3 D sound intensity measurements demonstrating an erratic pattern of sound intensity streamlines [1], [2] His approach was transferred from a lab to an actual car cabin upon request of a larger European car manufacturer. At 900 positions inside the car the 3D intensity is measured with a 3 D sound intensity probes using three particle velocity sensors. Such a probe is not susceptible to the pressure-intensity index. Several speakers that are driven in sequence are used as controlled sound sources. The results demonstrate that even with a single sound source, the 3D intensity streamlines are strongly bending, suggesting that far field techniques do not point towards the sound source."
A Balanced Approach for Wind Noise Control,"A balanced approach for wind noise control is presented in this paper. This approach is focused on improved sound insulation and low mass. Initially, the Sound Transmission Loss (STL) of tempered, standard laminated and acoustic laminated glasses for different thicknesses was measured in a STL suite. The critical frequency range was identified from in-vehicle noise measurements. These STL data and in-vehicle results provided the relevant information for a proposal with better acoustic performance and lower mass. The efficiency of this proposal was confirmed with new in-vehicle measurements."
Ultrasound Techniques for Leak Detection,"Leak detection of vehicle cabin interiors is an important quality inspection phase that typically has been handled with various time consuming, or potentially product damaging techniques. Leak detection in tank or pressure vessel applications is almost always a concern for gas or fluid containment in vehicles and in many other industries. Numerous techniques exist for the detection of leaks in these and other types of structures. When testing is required in a production environment, often the speed of leak detection is very important if all samples must be tested. The use of several ultrasound based methods for leak detection in vehicle cabins and pressure vessel applications is presented here. Ultrasound waves are typically classified as having spectral content greater than 20 kHz. In the case of leak detection in a production environment, frequently the ultrasonic spectrum is largely free from background noise content that dominates the audible spectrum. The method for the response measurement of ultrasonic signals presented here is with the implementation of high frequency microphones. The excitation methods presented here are an active method utilizing an ultrasonic emitter, a passive method relying on the passing of air through leak locations, and a vibro-acoustic method utilizing a small electro-dynamic shaker. The methods presented here have been tested for the existence of leaks in some structures, but have not been tested in this paper for the existence flaws and defects that may potentially lead to leaks in some structures after prolonged use."
Shearplate – A New Innovative Approach to Reduce Powertrain Noise,"This Paper is evaluating the development and effectiveness of using a Shearplate, a new and innovative approach to reduce powertrain noise and vibrations. The results show that the approach is offering monumental improvements in terms of reduced noise and vibrations. Sound quality evaluations also show very clearly that the approach is an effective countermeasure to the targeted problems. With the knowledge gathered during the development and with what is partly presented in this paper we now have an additional tool that car manufacturers can deploy in their efforts to design more fuel efficient and cleaner burning engines without sacrificing NVH performance."
How Advances in On-Road NVH Simulator Technology Have Enabled Firm Targets for Delivery at the Concept Phase,"One of the great challenges of the NVH development process is to ensure that customers and stakeholders in the vehicle team are involved in sound quality decision making throughout a new vehicle programme. Recent developments of interactive NVH simulators have enabled a cost-effective customer-focused method for capturing the opinions and decision making processes of people who are not NVH experts. This paper describes the latest enhancement to the NVH Simulator approach which allows the sounds of virtual vehicles to be evaluated whilst driving on-road. The sounds are created and presented to the driver in such a way that they appear totally natural and the assessor is not aware that they are synthesized. Since the subjective evaluations are performed on normal roads, key decision makers can understand, sign up with confidence to, and appreciate the value of the proposed sounds. The main emphasis of this paper is a recent case study in which the “On-Road” and “Desktop” simulators were used at the concept stage to deliver an exciting sound to enhance and compliment a new B-segment vehicle. The paper explains how the tools were used to: Set vehicle level sound quality targets to enhance the appeal of the vehicle, including customer surveys and the use of the On-Road Simulator for final sign off at target confirmation drive events. Understand the path and source contributions of a donor vehicle and key competitor. Create and demonstrate a strategy for practical realisation of the vehicle level target. The paper concludes with a discussion of the benefits of the approach and summarizes the next steps in the development of the technology and process."
Use of SEA to Support Sound Package Design Studies and Vehicle Target Setting,"Statistical Energy Analysis (SEA) vehicle models are well-accepted tools for predicting the high-frequency interior acoustic effects of a design change to the structure or sound package of the vehicle. [1] SEA models do not strongly depend on geometric details, which allows SEA to be uniquely used as an analysis tool very early in the vehicle design phase to identify potential Noise, Vibration, and Harshness (NVH) issues caused by proposed changes to acoustic or vibration source levels, component materials, construction details, or sound package details of the vehicle. SEA models can also be used to suggest alternatives while the vehicle is still in the development stages to compensate for a predicted or known degradation to NVH in a vehicle due to a design or source level change. This paper presents a case study in which validation testing and an SEA model were combined to obtain recommendations for the most effective sound package changes to meet NVH targets. The motivation behind this study and the role and benefits of the SEA model are presented. An overview of standard uses of SEA for vehicle design for component-level and full-vehicle level is given. SEA model validation methodology and results are discussed. A description of the measurement test plan and methodology is provided. The use of the SEA model to predict combinations of sound package changes to compensate for changes and to reach NVH targets for a new vehicle and the corresponding results are presented. Conclusions from the work are summarized."
In Situ PU Surface Impedance Measurements for Quality Control at the End of an Assembly Line,"With PU probes the sound pressure and acoustic particle velocity can be measured directly. Over recent years, the in situ surface impedance method, making use of such a probe, has proven to be an alternative to Kundt's tube measurements for product development type of work. The in situ method can also be used for the purpose of quality control on the acoustic material, be it during manufacturing or assembly, ensuring the best possible way to monitor the practical effectiveness of the acoustic package designed earlier on. In order to assess the variance of the acoustic package material leaving the assembly line, a relevant number of samples were taken over time. The quality of both the headliners, and the passenger seats were measured, of 25 cars of the same type. The robustness of the measurement method will be discussed, and the results will be presented."
Squeak and Rattle Prevention in the Design Phase Using a Pragmatic Approach,"Squeaks and Rattles (S&R) today are one of the main issues leading to a down ranking in quality perception of interiors in vehicles. Being annoyed by these types of noises, customers are driving up warranty and goodwill cost to many billion per vehicle model on lifetime. Still most of the problems are solved by automotive manufacturers and suppliers after they appear in hardware testing. Usually expensive solutions like felts and oil/grease are selected to solve the problem. However prevention is the key to eliminate unwanted Squeaks and Rattles early in the design phase based on CAD data and material information. This paper shows a pragmatic approach to support the design engineer to create a virtually S&R free CAD-model."
Modeling of In-Cabin Climate and Fogging of Windshield,"Passenger safety is considered as the central issue in vehicle design. One of the important factors that strongly affect driving safety is visibility through the windshield. Present model is mainly focused on the problem of fogging of windshields including the effects of latent heat and humidity. Model was studied for different climatic conditions like hot humid climate and cold climate. The effect of surface parameters like static contact angle, on defogging was also studied. Further, the effect of AC on in-cabin climate was also studied. Experimental results for condensation on a glass plate very well resembled with the glass-model results. The model helps in predicting fogging and understanding the actual thermal parameters leading to it and hence can be useful in optimizing these parameters so as to reduce fogging. It serves as a useful tool in optimizing the performance of an air conditioner."
A Review and Analysis of the Performance of Laminated Side Glazing in Rollover Accidents,"Advanced glazing has been investigated as a means by which to reduce occupant ejection in rollover accidents. However, most testing on these advanced glazing materials has not effectively captured the occupant kinematics typically seen in actual rollover accidents, and as a result, passing these tests does not ensure occupant retention. While current work has attempted to characterize the dynamic (impact) and static (push-out) material properties necessary for understanding the containment performance of advanced glazing, most testing has consisted of single impacts. Rollover accidents typically include multiple impacts and potentially long duration centrifugal forces on the side glazing. As such, there is little test and/or simulation data to support the theory that advanced glazing would substantially reduce the risk of occupant ejection in rollover accidents. The risk of head injury due to occupant impacts may not be significantly different between tempered and laminated glazing, but higher neck forces have generally been reported for laminated glazing. The laceration potential of laminated glazing may also be significant. This paper reviews the existing literature and testing in the area of automotive glazing materials, with specific emphasis on the containment potential of advanced glazing. We also present an analysis of the centrifugal forces on side window glazing due to occupant contact during rollover accidents. These forces most likely exceed the containment potential of laminated glazing."
Reducing a Sports Activity Vehicle's Aeroacoustic Noise using a Validated CAA Process,"Developing a low interior noise level of vehicles is a big challenge - even a greater one if one thinks about aeroacoustics. Aeroacoustic noise and its origins are usually identified with the help of prototypes when exterior design changes or the replacement of exterior parts like side mirrors are very limited. However, computational aeroacoustic (CAA) methods in virtual project phases offer more design options for the vehicle's geometric shape. The early consideration of aeroacoustic relevant design changes helps to keep project costs low by avoiding tool changes. This paper describes MAGNA STEYR's virtual aeroacoustic process starting from standardized model generation and simulation of wind noise, including the validation of computational results via comparison with measurement data gathered in an acoustic wind tunnel. The simulations are carried out using the commercial CAA code “PowerFLOW” (Exa) based on the Lattice-Boltzmann method. CAA post-processing results with the aim to detect hot spots and to derive effective measures are presented. As a typical application, a design modification example is highlighted: Pressure fluctuations on a vehicle's side window are influenced strongly by the design of the a-pillar. Improvement potential was identified by analyzing simulations results and a-pillar modifications were developed which led to a validated interior noise reduction of 1 dB(A)."
Vibro-Acoustic Simulation of Side Windows and Windshield Excited by Realistic CFD Turbulent Flows Including Car Cavity,"Nowadays, the interior vehicle noise due to the exterior aerodynamic field is an emerging topic in the acoustic design of a car. In particular, the turbulent aerodynamic pressure generated by the air flow encountering the windshield and the side windows represents an important interior noise source. As a consequence PSA Peugeot Citroën is interested in the numerical prediction of this aerodynamic noise generated by the car windows with the final objective of improving the products design and reducing this noise. In the past, several joint studies have been led by PSA and Free Field Technologies on this topic. In those studies an efficient methodology to predict the noise transmission through the side window has been set up. It relies on a two steps approach: the first step involves the computation of the exterior turbulent field using an unsteady CFD solver (in this case EXA PowerFlow). The second step consists in the computation of the vibro-acoustic transmission through the side window using the finite element vibroacoustic solver Actran. The present paper extends this methodology for the handling of multiple windows, i.e., the two front side windows and the windshield. The complete car cavity is modeled as well. First, a complete description of the method and the finite element model is provided, from the boundary conditions to the different components involved, like the windows, the seals and the car cavity. The total wind noise level results and the relative contributions of the different windows are then presented and compared to measurements for a real car model. The influence of the flow yaw angle (0° versus 10° orientation) is also assessed."
Studies on Neutral Gear Rattle in Early Stage Design,"In today's competitive automobile market, customers have become more sensitive towards NVH behavior of the vehicle than ever. The noise generated by gear rattle is one of the main contributors towards customer's overall NVH perception. This paper adopts a model based design approach towards gear rattle phenomenon to predict the tendency of gear rattle at a very early stage of design. This up-front understanding of gear rattle will potentially reduce the expensive design changes and iterations at later stages. A single unloaded gear pair is modeled in AMESim software, which is then extended to the complete gearbox in neutral condition. The sensitivity of rattle index for different input parameters is studied. Analysis on uncertainty propagation is carried out to find the rattle index distribution for Gaussian variation of input parameters. A novel rattle index based on Jerk is proposed and compared with the existing index. Both the indices are later predicted for the complete gearbox and the contribution of each pair towards rattle is analyzed."
Design Optimization of Acoustic Enclosure for Noise Reduction of Diesel Generator Set,"Diesel engine generator (DG) sets used in industrial plants and residential/official buildings cause serious noise problems if not (canopised) properly. Generally, DG set engines used are with rotational speed of 1500 rpm. In present study automotive diesel engine with 3000 rpm speed was converted for Genset application. Due to higher speed, engine noise levels and its cooling requirements were quite high. Objective of the study was to optimize the design of an enclosure for the said DG set to meet requirements of low noise and proper ventilation to comply MoEF legislative limits. A detailed Noise Source Identification (NSI) was carried out to identify and rank different noise sources. A Hybrid approach which consists of experimental DOE and simulation based on Boundary Element Method (BEM) was used for enclosure design. Design variables like enclosure dimensions, sound absorbing materials and louvers were used in optimization study. Final validation was done on modified enclosure prototype for noise level and internal temperature. Substantial noise level reduction of 8 dB was achieved with appropriate ventilation."
Road Test Measurement and SEA Model Correlation of Dominant Vehicle Wind Noise Transfer Paths,"In order to effectively use CAE to meet wind noise NVH targets, it is important to understand the main wind noise transfer paths. Testing confirmation of these paths by means of acoustic wind tunnel test is expensive and not always available. An on-road test procedure including a “windowing” method (using barriers) was developed to measure wind noise contribution at important higher frequencies through the main transfer paths, which were shown by test to be the glasses at a typical operating condition in which wind noise was dominant. The test data was used to correlate a full-vehicle SEA (Statistical Energy Analysis) model that placed emphasis on the glass properties, main noise transfer paths, and interior acoustic spaces while simplifying all other transmission paths. A method for generating wind noise loads was developed using measured glass vibration data, exterior pressure data, and interior acoustic data. The individual glass paths were correlated and a baseline model was developed including the noise contribution of all glass paths and a lumped non-glass flanking path. Design studies of the glass properties were performed, especially to explore the overall acoustic performance potential of laminated glasses, individually and in combination, which have potential to reduce vehicle weight. These results and recommendations of how this technique and baseline model can be extended to other vehicle body styles and conditions are presented."
Can You Hear It Now? Time-Domain Source-Path-Contribution Applied To a Diesel Engine,"Source-Path-Contribution (also known as transfer path analysis or noise path analysis) comprise a well-known set of techniques that have traditionally been performed in the frequency domain. With advancements and modern techniques, these same principles can be applied accurately in the time-domain. Foremost among the benefits of this are an ability to analyze transient events, and the ability to listen to the contributions from various sources instead of merely viewing them. This paper demonstrates the analysis of a diesel engine vehicle utilizing time-domain source-path-contribution techniques."
Influence of the Gyroscopic Effects on Friction Induced Vibration in Aircraft Braking in System,"Aeronautical brakes are subject to non-linear unstable vibrations. In particular, two modes appear and present a risk for the structure. Firstly, the whirl modes consist of a rotating bending motion of the axle out-of-phase with the brake torque tube. It is due to a coupling of two bending modes of the axle in orthogonal directions. Secondly, the brake squeal mode resulting from stick-slip or sprag-slip phenomena consists of a rotational motion of the brake around the axle. Those vibrations are not resulting from an external excitation but are friction-induced self-excited. Hence, they are dependent on tribological phenomena specific to carbon disks and are in particular controlled by the friction coefficient μ. In order to take into account the dynamical aspect in brake design, Messier-Bugatti-Dowty wants to simulate modes and acceleration g's levels. This article deals with the improvement of such a model. A finite element of the brake exists. It is able to reproduce whirl modes and squeal mode. In order to improve it, physical phenomena must be introduced. Here, the impact of gyroscopic effects is evaluated. For this, an analytical model is built to determine the consequences on frequencies and stability."
A Study of Experimental Acoustic Modal Analysis of Automotive Interior Acoustic Field Coupled with the Body Structure,"The accuracy of the vibro-acoustic coupled system model for the low frequency range depends on how accurately modal characteristics are represented at the input, output, and the structure-acoustic coupling surface. This study focus on extracting the detailed acoustic mode shapes on the coupling surface for the improvement of the model accuracy. In order to extract the acoustic mode shapes on the coupling surface from an experimental test, the applied method is initially evaluated by FE model results. As the next step, the same procedure in the previous step is applied to the test data of an actual vehicle for the purpose of extracting the detailed acoustic mode shapes at the coupling surface of the body structure and cabin interior acoustic field."
Vehicle Mid-Frequency Response Using the Superelement Component Dynamic Synthesis Technique,"This paper presents the Component Dynamic Synthesis (CDS) superelement creation, which contains the loading frequency information and is much faster than the Component Mode Synthesis (CMS) method in the residual run. The Frequency Response Functions (FRFs) are computed using the direct frequency response method and the inversion of dynamic stiffness matrix is done using the singular value decomposition (SVD) method for every discrete frequency in the frequency range of interest. The CDS will be very efficient and economical for design of experiments and robust optimization, where hundreds of runs are required. The CDS super element can be used when there is a large number of residual runs on a very large vehicle model at higher end of the frequency range of study. For the residual analysis to run as fast as possible, all components, except very small ones, need to be converted into CDS superelements. Numerical results demonstrate the efficacy of the CDS method for the prediction of mid-frequency responses for vehicle vibration and noise."
Method for Detecting Planar Surfaces in Outdoor Urban Environments,"The ability to detect and recognize buildings is important to a variety of vision applications operating in outdoor urban environments. These include landmark recognition, assisted and autonomous navigation, image-based rendering, and 3D scene modeling. The problem of detecting multiple planar surfaces from a single image has been solved with this technology."
Practical Loop-Shaping Design of Feedback Control Systems,"An improved methodology for designing feedback control systems has been developed based on systematically shaping the loop gain of the system to meet performance requirements such as stability margins, disturbance attenuation, and transient response, while taking into account the actuation system limitations such as actuation rates and range. Loop-shaping for controls design is not new, but past techniques do not directly address how to systematically design the controller to maximize its performance. As a result, classical feedback control systems are designed predominantly using ad hoc control design approaches such as proportional integral derivative (PID), normally satisfied when a workable solution is achieved, without a good understanding of how to maximize the effectiveness of the control design in terms of competing performance requirements, in relation to the limitations of the plant design."
Safely Stopping Motion Using Discrete Wiring,"Functional machine safety using discrete wiring is an established way to protect workers from injury, and protect companies from the expense associated with accidents and downtime."
SOFIA Closed- and Open-Door Aerodynamic Analyses,"Work to evaluate the aerodynamic characteristics and the cavity acoustic environment of the SOFIA (Stratospheric Observatory for Infrared Astronomy) airplane has been completed. The airplane has been evaluated in its closed-door configuration, as well as several open-door configurations (see figure). Work performed included: acoustic analysis tool development, cavity acoustic evaluation, stability and control parameter estimation, air data calibration, and external flow evaluation."
EDITORIAL: The unforgettable pyramid on the hood,"If you're old enough to remember 1990, you may recall the best television ad of the year. It showed the front end of the all-new Lexus LS400 sedan against a black background. A multi-level pyramid of champagne glasses glistened in the center of the car's hood. It was demonstration time, and the demo was all about Noise, Vibration and Harshness-and the lack of it."
How a Tier 2 tackles NVH,"Saint-Gobain invested in anechoic testing so small components can make a big NVH difference. Saint-Gobain is a company that understands how vital NVH R&D is for perceived quality. Unwelcome noise is a major challenge in premium cars, but it is the minor components that matter. For Saint-Gobain that means particularly its bearings and tolerance rings. The French company, founded in the 17th century, has become so determined these components can assist with reducing vehicle NVH that it has built its own semi-anechoic chamber, hardly a routine investment for a Tier 2 supplier. Until recently, Saint-Gobain used facilities at European universities and a specialist test site in Germany for NVH development, but its own chamber in the U.K. will help the company to better understand OEMs' systems and improve performance. The ISO 3745- and 3744-compliant facility in Bristol was established with support from Southampton University's Institute of Sound and Vibration Research (ISVR Consulting) and by Brüel & Kjaer, with headquarters near Copenhagen, Denmark."
"Compact, Lightweight, CMC-Based Acoustic Liner","In the wake of recent developments that have reduced fan and jet noise contributions to overall jet-engine noise, aircraft designers are turning their attention toward reducing engine core noise. Innovators at NASA’s Glenn and Langley Research Centers are developing a compact, lightweight acoustic liner based on oxide/oxide ceramic matrix composite (CMC) materials."
"2017 Pacifica is first hybrid minivan, rides on all-new FCA platform","Despite the popularity of SUVs and CUVs, nothing beats a minivan for its combination of interior flexibility, ingress/egress, passenger comfort, cargo hauling and, in some cases, fuel efficiency. While the segment isn't as large as it was in 2000, when sales peaked at 1.37 million deliveries in North America, about 500,000 minivans are still sold annually-ample profit-spinning volume that analysts expect will be sustained through at least 2020. As millions of customers would likely attest, the minivan is “still the best transportation ‘tool’ for families,” observed Tim Kuniskis, head of FCA's passenger car brands, when he pulled the cover off Chrysler's 2017 Pacifica-the company's sixth generation minivan. It was shown to Automotive Engineering and other media on embargo prior to the car's official debut at the 2016 North American International Auto Show."
Enhancing Image Clarity in the SWIR,"A chromatic or color-corrected lenses for use in the visible portion of the electromagnetic spectrum have been addressed in literature, textbooks, and industry journals as early as the 18th Century. Many of these accounts by scientists and optical designers detail a method of selecting two dissimilar materials to form an achromatic pair or doublet with the ability to greatly counter image blurring resulting from the dispersive nature of refractive optical elements. Whether these tried and true optical formulae produce equally successful results in wavelengths beyond the visible range warrants further examination."
Using Fan-poled Crystals to Tune Ti:S Lasers,"Titanium:Sapphire (Ti:S)-based laser systems have revolutionized ultrafast research from biological imaging to high energy physics. Ti:S has a very broad gain bandwidth (680-1080 nm) but many applications require even broader tuning ranges covering UV, visible, and longer IR wavelengths. Frequency doubling, tripling, and quadrupling extend access to the 190-540 nm range. Ultrafast optical parametric oscillators (OPOs) pumped by Ti:S lasers reach beyond 1080 nm and fill in the “Ti:S gap” (540 to 680 nm)."
Experimental Sensitivity Studies on Glass Bonding Urethanes,"This paper investigates the sensitivities of glass bonding adhesives to the dynamic characteristics of automotive body structures. Experimental modal analysis was conducted to study the damping, response amplitude, and stiffness of different adhesives to a door assembly and a vehicle body. Three different glass bonding adhesives were used in this study. Performance advantages of using these adhesives are given."
Design and Construction of a Small Reverberation Chamber,"As a manufacturer of a complete line of acoustical materials American Acoustical Products needed to construct a laboratory that would allow the characterization of the acoustical properties of its materials. Reference panels of materials were available that had been previously measured for absorption in a full scale reverberation chamber. A design for a small reverberation chamber was developed based on the Toyota Specification TSL 0600G-4 which includes a small transmission window for STL measurements. This design has the advantage of being constructed with no parallel surfaces, is tall enough to walk into and is optimized for measuring samples between 9 and 30 square feet in surface area. In order to allow the facility to function effectively several innovative techniques have been employed. To maximize the reverberation time the walls were constructed using constrained layer damped and mass loaded sheetrock on a timber frame. The walls and roof were constructed without cavities to avoid resonances and all the internal surfaces including the door and transmission window sealing panel were tiled with ceramic tiles for maximum reflectivity. The room's external surfaces were lined with sound absorbing foam to improve the sound transmission loss measurements. To generate a diffuse sound field, the chamber was excited by a NXT® Distributed Mode Loudspeaker which has virtually no directivity. To measure the room response, pressure zone microphones were placed in the corners of the room where all the resonant modes have pressure maxima. Finally the analysis of the RT60 sound decay was measured by a two channel real time analyzer using a studio mixing desk to switch between microphones. Results from the small reverberation room will show how closely the measurements agree with the full scale tests carried out to ASTM C423 at the Hudson Valley Acoustics Laboratory12"
N-Hance: Software for Identification of Critical BSR Locations in Automotive Assemblies using Finite Element Models,"Today's highly competitive automotive industry is constantly looking for ways to improve the perceived quality of its vehicles. Perceived quality defined as the sense of touch, feel and sound that the customer perceives in a vehicle is seen as one of the areas with maximum potential for increasing customer satisfaction. Buzz, Squeak and Rattle (BSR) is one of the major contributors towards the perceived quality in a vehicle. Almost all of the annoying noises that the customer hears can be classified into a buzz, squeak or rattle. Traditionally BSR in subsystems and components of a vehicle have been identified and rectified through extensive hardware testing. With the auto companies and suppliers being challenged to cut structural costs, eliminate costly hardware builds, and bring products to market faster by reducing development cycles, increasing math analysis of subsystems and components for such perceived quality issues is desirable. In line with the needs of the industry to perform math-based analysis and to improve the perceived quality of vehicles, Lohitsa and GM partnered to validate N-hance. BSR. N-hance.BSR is a software tool developed exclusively to identify BSR critical-locations, for the finite element model that is subjected to a vibration profile of interest. The software has been fully automated to rank order the issues based on their severity and thus enables analysis and interpretation of the results, with minimum user input. N-hance.BSR is a fully contained software including pre and post processors, user friendly GUI and report generating capabilities. The tool was used to predict critical-locations on two different subsystems and the results from the analysis were then correlated to BSR issues identified through hardware testing. In both cases the correlation was greater than 75%, taking into account only those issues from hardware components that were adequately represented in the finite element model. An overview of the method is presented followed by results from the BSR evaluation of an instrument panel and a door."
Solution for Direct Solar Impingement Problem on Landsat-7 ETM+ Cooler Door During Cooler Outgas in Flight,"There was a thermal anomaly of the landsat-7 Enhanced Thematic Mapper Plus (ETM+) radiative cooler cold stage during the cooler outgas phase in flight. With the cooler door in the outgas position and the outgas heaters enabled, the cold stage temperature increased to a maximum of 323 K when the spacecraft was in the sunlight, which was warmer than the 316.3 K upper set point of the outgas heater controller on the cold stage. Also, the outgas heater cycled off when the cold stage was warming up to 323 K. A corrective action was taken before the attitude of the spacecraft was changed during the first week in flight. One orbit before the attitude was changed, the outgas heaters were disabled to cool off the cold stage. The cold stage temperature increase was strongly dependent on the spacecraft roll and yaw. It provided evidence that direct solar radiation entered the gap between the cooler door and cooler shroud. There was a concern that the direct solar radiation could cause polymerization of hydrocarbons, which could contaminate the cooler and lead to a thermal short. After outgas with the cooler door in the outgas position for seven days, the cooler door was changed to the fully open position. With the cooler door fully open, the maximum cold stage temperature was 316.3 K when the spacecraft was in the sunlight, and the duty cycle of the outgas heater in the eclipse was the same as that in the sunlight. It provided more evidence that direct solar radiation had entered the gap between the cooler door and cooler shroud. Cooler outgas continued for seven more days, with the cooler door fully open. The corrective actions had prevented overheating of the cold stage and cold focal plane array (CFPA), which could damage these two components. They also minimized the risk of contamination on the cold stage, which could lead to a thermal short."
MAGDOOR - Magnesium in Structural Application,"The objectives of the project is to contribute to reduced emissions by weight reduction, which in this study is made by replacing the inner door steel structure with cast magnesium. Weight target is 55 % relative steel, implying vehicle lightening by more than 25 kg, hence saving 200 litre fuel during the life of the vehicle. A magnesium door concept is expensive in high volumes, and the risks include incomplete die filling, multimetal incompatibility and low strength. Cost efficiency implies to design for integration and commonality. Ductile alloys, correct ingate shape and optimized wall thickness is necessary to meet the impact and quality requirements of the door structure. Joining Al to Mg is mainly limited to adhesives and promising Mg surface treatment alternatives to chromateing have been evaluated."
Localized Nonlinear Model of Plastic Air Induction Systems for Virtual Design Validation Tests,"Plastic air induction system (AIS) has been widely used in vehicle powertrain applications for reduced weight, cost, and improved engine performance. Physical design validation (DV) tests of an AIS, as to meet durability and reliability requirements, are usually conducted by employing the frequency domain vibration tests, either sine sweep or random vibration excitations, with a temperature cycling range typically from -40°C to 120°C. It is well known that under high vibration loading and large temperature range, the plastic components of the AIS demonstrate much higher nonlinear response behaviors as compared with metal products. In order to implement a virtual test for plastic AIS products, a practical procedure to model a nonlinear system and to simulate the frequency response of the system, is crucial. The challenge is to model the plastic AIS assembly as a function of loads and temperatures, and to evaluate the dynamic response and fatigue life in frequency domain as well. This paper presents a modeling procedure for nonlinear plastic products, such as AIS assemblies, by using an array of locally linearized systems, for virtual design validation tests. The measurement results of physical DV tests are first presented to quantify the basic nonlinear response behaviors of the plastic AIS products. The proposed finite element modeling method is then evaluated based on correlation with the measured test results. The localized nonlinear model is thus employed to simulate the frequency response of the plastic AIS products and to identify weak spots of the design. Durability evaluation of the AIS product is then conducted in terms of estimated life, based on the simulated dynamic stresses and material fatigue properties. The presented procedure has helped the engineering team to identify potential durability design problems without a prototype, and to guide the design changes and modifications."
Standard Metrology for Vehicular Displays,"The scope of this SAE Standard is to provide methods to determine display optical performance in all typical automotive ambient light illumination - with focus on High Ambient Contrast Ratio, which is critical for display legibility in a sunshine environment. It covers indoor measurements and simulated outdoor lighting. It is not the scope of this document to set threshold values for automotive compliance, however some recommended values are presented for reference."
Effects of Brake Pad Boundary Contact Surfaces on Brake Squeal,"The disc brake corner assembly is comprised of several subsystems (brake pad, caliper, rotor etc.) which have interfaces between two or more of these structures. The brake pad assembly as the subsystem connecting the rotor to the caliper has specific areas of contact which influence the onset and potential to control brake squeal. The primary excitation interface occurs between the friction pad and rotor surface. The contact is initiated by the piston apply force on the brake pad insulator. Contact interface reaction forces, displacements and deformations are generated and form the natural and geometric boundary conditions of the overall system. Brake squeal characteristics are strongly affected by these conditions. The study focuses on brake system dynamic response to interface contact conditions. The brake insulator and pad assembly interacting with the brake piston as well as caliper are evaluated. Modifications that change the system dynamics through these interfaces are also assessed by dynamometer testing. Properties including compliance, interface friction and traction, damping, decoupling and isolation are discussed with respect to their potential impact on mechanisms leading to brake squeal. Three practical solutions that have been proven to decrease brake squeal via interface modifications are demonstrated at two interface areas 1) Piston to insulator modifications via changes in friction level as well as decoupling and damping 2) Caliper assembly interface with the backing plate incorporating friction level changes with decoupling and damping at the attachment point. Comparative test results indicating the effect of these modifications are presented."
Improvement in Noise Transmission Across Firewall of a Passenger Car,"Firewall of a car separates the engine compartment from the cabin and acts as a barrier for engine noise entering the passenger compartment. Hence noise transmission through the firewall plays an important role in determining the interior noise of a car. Noise Reduction measurement technique is useful to evaluate existing and potential acoustic treatments of the firewall of a car. This paper presents two systematic measurement approaches for quantifying the acoustic performance of firewall insulation materials across the firewall of a car. First a Volume Velocity Source was placed in the passenger compartment and noise reduction was measured across the firewall with different configurations of firewall acoustic treatments. Similar exercise was repeated by installing an actual vehicle firewall in a sound transmission loss suite and measuring the noise reduction across the firewall. Measurement techniques such as leakage detection and sound intensity mapping were used to enhance the understanding of the noise transmission paths through the firewall and to rank the dominant leakage areas. Based on the above, appropriate modifications to the car have been carried out and evaluated for reducing the noise transmitted through the firewall of the car. To assess the influence of improvement in noise reduction across the firewall on the interior noise of the car, in cab noise measurements were carried out with the engine running on the test track."
Brake NVH: Testing and Measurements,"As other vehicle systems have become more refined, more attention must be placed on brake NVH issues because they can cause a negative customer experience. From the laboratory to the road, the use of technology as well as further study by engineers is helping to lessen noise, judder, and vibration in cars. This book provides readers with a fundamental understanding of current practices for measuring and testing brake NVH. From coverage of basic definitions and concepts to in-depth analysis of on-road testing procedures, it will serve as a comprehensive reference guide for brake test technicians, test engineers, lab managers, and others who work on making brakes quieter, smoother, more refined, and more reliable. Readers will learn how to test for brake noise, what tools to use, and which recent standards and practices have led to the successful measurement of brake noise and vibration. Topics covered include: • Common brake noise and vibration issues • Instrumentation, transducers, and other technical details • Measurement practice for laboratory and on-road testing • Brake pad damping and natural frequencies • Current trends in brake noise and vibration measurements"
Principles of Vibration Analysis with Applications in Automotive Engineering,"This book, written for practicing engineers, designers, researchers, and students, summarizes basic vibration theory and established methods for analyzing vibrations. Principles of Vibration Analysis goes beyond most other texts on this subject, as it integrates the advances of modern modal analysis, experimental testing, and numerical analysis with fundamental theory. No other book brings all of these topics together under one cover. The authors have compiled these topics, compared them, and provided experience with practical application. This must-have book is a comprehensive resource that the practitioner will reference time and again."
Dispersion of Test-Based NVH Characteristics at Various Trim Levels,"A broad measurement campaign was run at Volvo aiming at the evaluation of dispersion in test-based NVH characteristics of a car body and at the derivation of reference data for judging the accuracy of CAE predictions. Within this work 6, nominally identical, vehicles were tested. Tests included operational noise on Complete Vehicle (CV) level (road noise, engine noise and idling noise), NTF, VTF & Acoustic FRF measurements in CV, Trimmed Body (TB) & TB-Stripped (TBS) configurations. Additionally, modal analysis and NTF, VTF, AFRF tests were carried out on 4 BIPs of the same vehicle type. Further, limited tests were carried out on 28 vehicles of the same type. The aim of the work was to study the development of dispersion with increasing complexity of the test object, from the BIP to TB and CV. In this respect this study is unique - there has been several studies regarding the dispersion in test results but the studies that trace the dispersion between different levels of complexity of the test object are scarce if not non-existent. In parallel with this, CAE activities were carried out in order to create CAE models corresponding exactly to the test objects, for all trim levels. Even the boundary conditions were modeled with great detail. In this way, it was possible to study the development of CAE prediction accuracy with increasing complexity of the test object. Further on, several classes of measurement points' locations were studied. In the paper the dispersion results will be presented and some comments regarding prediction accuracy and its assessment will be given."
Influence of Tire Air-borne Noise on Vehicle Loudness Predicted during Design Phase Based on Hybrid Internal Noise Contribution Model,"The development of new technologies that reduce engine size and improve performance, combined with the introduction of hybrid and electric vehicles, make tire noise critically important for the new generation of automobiles. Tire noise transmission into the passenger compartment can be classified as either air-borne or structure-borne sound. Both of these mechanisms are very complex to predict because tires are highly non-linear, subject to large static, dynamic and centrifugal loads; they suffer from impact, stick and slip forces; and the pumping of air in the tire grooves is complicated. Customers today demand more sophistication of products in terms of interior noise; thus, sound quality metrics have earned an important role during the design phase allowing human perception of noise to be predicted and improved with reduced cost in a way that addresses consumer preferences. Of the various metrics, loudness has been shown to be the most important metric due to consideration of masking effects on human hearing. This paper discusses global loudness assessment of a vehicle during its design phase for two different types of tires through a hybrid internal noise contribution model with the following inputs: i - powertrain forces (surrogate data); ii - tire radiated noise (measured from a carryover vehicle through of a chassis roll dynamometer within a hemi-anechoic chamber), iii - noise transfer functions (simulated using FEM), iv - acoustic noise reduction functions (simulated using SEA)."
Automotive Electronics Testing for Conductive Coated Heat Reflective Windows,"The electromagnetic interference between the conductive coating in heat reflecting automotive glass and vehicle electronics can limit the application of such technology. A number of methods are available to maintain electromagnetic compatibility and the function of RF electronics in the passenger compartment, while accruing the heat load reduction benefits of the coating. This paper provides detailed test data showing the antenna performance differences resulting from the conductive windshield transmission of RF signals."
Engineering Moveable Glass Window Seals of Automotive Door Using Upfront CAE,"The traditional moveable glass window seal development process has relied heavily on physical prototypes for design verification. Due to frequent styling changes and an overall reduction in design time, physical prototypes for the glass window seals have proven to be inadequate. Utilization of computer aided engineering (CAE) tools is necessary in order to shorten lead time. CAE tools will help to decrease expensive prototyping, free up valuable manufacturing line time, and improve overall quality. A cross functional approach has been applied to expand the scope beyond traditional methods of moveable glass window seal design, such as wedged boarding, into new computerized modeling methods. The CAE was used to address major requirements of the glass window seals including glass velocity, glass stall force, sealing-ability, seal durability, seal assembly, seal appearance, and regulator motor current. A systematic process is used for the glass window system design development using CAE to insure that production parts will meet all functional and assembly process objectives."
Dimensional Management Process Applied to Automotive Door Systems,The processes utilized in building-up and installing automotive door assemblies to a body are required to address a complex interaction of dimensional requirements. The Dimensional Management Process is employed to arrive at the optimum design and process to achieve the many functional and appearance related requirements of the door system. This paper will demonstrate the application of the Dimensional Management Process to the typical automotive door system and the use of integrated three-dimensional tolerance analysis to compare different door assembly and installation methods for the purpose of achieving an optimum appearance and functionality of the door system.
Testing of New Composite Side Door Concepts,"Car side doors are one of the most complex parts of the body, because this component has to meet a lot of requirements. Independent of the material - steel, aluminum, magnesium, or fiber-reinforced plastics (FRP) - there are multiple important requirements. In this paper, testing methodologies for self-supporting car side doors made from FRP are presented based on different conceptual design studies using these innovative materials. These doors and related testing methodologies have been developed in joint research and pre/advanced-development projects with different partners, car manufacturers as well as suppliers. The importance and benefit of benchmarks, advanced experimental material analysis, substructure and full-size component testing in the product development process is discussed. Furthermore important links to the CAE-process are referred and the significant value on the whole development process is demonstrated. Test data for new composites car side doors based on different conceptual design are presented and methodologies for further improvement of the development process suggested."
Analytical Robust Door Hinge System Design Taguchi Approach,"The automotive industry faces many competitive challenges including weight and cost reduction to meet CAFE standards. In particular, a non robust door hinge optimized for weight reduction may cause high warranty and durability problems in the field. Many analytical techniques such as optimization and sensitivity analysis have been widely used in a hinging system design. However, none of the techniques include robustness and the design variation in the analysis. This paper presents an application of finite element method coupled with the parameter design using Taguchi's design of experiment. This approach identified the hinge design variables in the pillar-hinge-door system and improved the robustness of vertical rigidity performance."
Slam Life Assessment Method for Closures Durability,"The Slam Life Assessment Method (SLAM) is a CAE solution that predicts the durability of automotive closures subject to a repetitive slamming load. Moreover, SLAM is a fully automated program that integrates several software and CAE analyses into a single turnkey solution. SLAM employs the physics of the slam event to succeed where prior analysis methods fail. Standard CAE analyses such as inertia relief, normal modes, and forced loading response cannot capture the physics of the dynamic stress states that occur during a durability slam event. Furthermore, SLAM produces insight into the behavior of the door system that cannot be gained through testing. We have shown that it is possible to predict the performance of a door subject to a slam-closed event with 80-90% reliability. This method has been realized via motivation to solve numerous door panel cracking issues associated with preliminary door designs. Correlation of SLAM methods with physical tests led to the ability to “virtually” slam and redesign doors before prototypes were made. To date, SLAM is used mainly on door systems, however, it is easily extended to hood, decklid, and liftgate systems. SLAM simulations have proven their usefulness on aluminum hood “tea cup” designs. SLAM saves product development time and money by reducing the number of prototypes needed to evaluate a design proposal. It allows evaluation of more design alternatives, reduces weight, and results in fewer production level failures. As the automotive industry moves towards a 10-year durability life, the testing times and number of samples continues to increase in order to meet these tougher requirements. Door slam testing can take several months to schedule and complete, whereas, SLAM can reduce this process to a few hours. The net result is a benefit to the customer in the form of a structurally optimized closure assembly that has no durability problems."
Ultralight Intercostal Automatic Fastening System,"A high level directive is in place at the St. Louis facility to increase the use of automation in our assembly processes. Likewise, the C-17 program has implemented a series of cost reduction initiatives. In line with these initiatives we have been implementing automatic fastening equipment into a variety of non-traditional applications. The C-17 Cargo Door Intercostals can easily be described as “non-traditional” and represent unique challenges for automatic fastening. The concept for The Intercostal Riveter uses proven drill and riveting techniques. However, it has miniaturized components and will be utilized like a portable power tool. Manipulated by a single operator, it will be maneuvered around and throughout the C-17 Cargo Door Assembly Jig. It is ultra-lightweight and will have a C-Frame constructed from carbon-epoxy composite material."
A New Component Test Methodology Concept for Side Impact Simulation,"This paper describes the development of a new component test methodology concept for simulating NHTSA side impact, to evaluate the performance of door subsystems, trim panels and possible safety countermeasures (foam padding, side airbags, etc.). The concept was developed using MADYMO software and the model was validated with a DOT-SID dummy. Moreover, this method is not restricted to NHTSA side impact, but can be also be used for simulating the European procedure, with some modifications. This method uses a combination of HYGE and VIA decelerator to achieve the desired door velocity profile from onset of crash event until door-dummy separation, and also takes into account the various other factors such as the door/B pillar-dummy contact velocity, door compliance, shape of intruding side structure, seat-to-door interaction and initial door-dummy distance. This method is capable of reproducing the characteristic “double-peak” of the door velocity profile and, can be used for side airbag evaluation, by simulating the close-in velocity and distance between the side structure and dummy. In this approach, the door velocity profile is simulated in four phases: In the first phase, a pre-crushed door mounted on a ‘Door sled’ (at approximately the same distance from the dummy as in a car), is accelerated by the HYGE until it impacts the stationary dummy, to generate the first peak. In the second phase, from the onset of dummy contact, the door sled is decelerated by a honeycomb block (mounted on another ‘Base sled’), simulating the first ride-down of the velocity profile. During this phase, the HYGE is dormant. In the third phase, the HYGE accelerates both the Door and Base sleds together to simulate the second peak. In the fourth phase, the Door and Base sleds are decelerated until door-dummy separation by means of a VIA decelerator system, thus simulating the entire door velocity profile from start of crash event until the door and dummy separate. In conclusion, the MADYMO model demonstrates the feasibility of the concept, pending experimental prove-out on the sled."
Thermal Qualification of the Sciamachy Passive Cryogenic Cooler,"This paper describes the design and qualification of this SCIAMACHY Radiant Cooler and focuses on the methods and results of the thermal balance and thermal verification test of the Radiator Reflector Unit flight model, performed late summer 1998. A new type of temperature control has been used that proved to increase speed, simplicity and accuracy of the test itself as well as the evaluation afterwards. The RRU TB/TV test was successful in gathering all significant thermal parameters. After refurbishment of the cooler door and a requalification test of its transient performance all cooler parameters are acceptable and its thermal performance is within specification."
Accuracy Determination of Sheet Metal Forming Simulation Using One-Step Code,"The use of numerical simulation in the design of stamped components has become common industrial practice. Inverse one-step codes are among the fastest to provide answers but, unlike incremental codes, they need an additional verification phase. Given this context, IVECO has conducted experimental testing work on the plastic deformations measured on two industrial components obtained by means of sheet steel stamping. The two components, one with structural functions (sliding door upper reinforcement) and the other one with esthetic functions (rear left door skin), have been selected as representative of the various feasibility and process issues connected with sheet metal drawing."
Experimental and Computational Study of Vehicle Surface Contamination on a Generic Bluff Body,"This paper focuses on methods used to model vehicle surface contamination arising as a result of rear wake aerodynamics. Besides being unsightly, contamination, such as self-soiling from rear tyre spray, can degrade the performance of lighting, rear view cameras and obstruct visibility through windows. In order to accurately predict likely contamination patterns, it is necessary to consider the aerodynamics and multiphase spray processes together. This paper presents an experimental and numerical (CFD) investigation of the phenomenon. The experimental study investigates contamination with controlled conditions in a wind tunnel using a generic bluff body (the Windsor model.) Contamination is represented by a water spray located beneath the rear of the vehicle. The aim is to investigate the fundamentals of contamination in a case where both flow field and contamination patterns can be measured, and also to provide validation of modelling techniques in a case where flow and spray conditions are known. CFD results were obtained using both steady RANS and unsteady URANS solvers, combined with particle tracking methods. Steady RANS does not capture the wake structures accurately and this affects the contamination prediction. URANS is able to recover the large-scale wake unsteadiness seen in the experimental data, but the difference between the experimental and computational contamination distributions is still notable. The CFD is also able to provide further insight by showing the behaviour of particles of different sizes. Large particles are found to take on a ballistic trajectory and penetrate the wake. In contrast, small particles are shown to be less likely to become entrained into the wake."
PSV Emergency Exits: Passenger Behaviour and Exit Design,"This study tested the speed and ease with which individual passengers could open and use the emergency exits currently provided on buses and coaches. The survey found that passengers believed that certain emergency exits, such as doors and hinged windows, would be easy to use in an emergency, that they knew how to use them and that instructions would help if they were uncertain. Twenty exit types were then tested with passengers, including emergency doors, ‘continental’ doors, roof hatches, hinged windows, breakglass windows and the emergency operation of service doors. It was found that passengers' expectations were generally not being met. Inappropriate handle design, location, feedback, anti-tamper cover guards and unclear instructions were found to result in significant delays in evacuation. The study recommends design improvements in these areas together with a consistent approach to the design and provision of emergency exit signage, conspicuity and instructions. It also recommends that high level doors are equipped with steps and that if window exits are to be retained these should be hinged rather than break-glass as the latter have severe disadvantages."
Safety and Security Considerations of New Closure Systems,"A closure system for automotive security and driver comfort has been developed. The system combines a passive entry system and an electronic door latch system. The passive entry system utilises a single chip transponder for vehicle immobilisation, passive entry and remote control functionality. The form factor free transponder enables the integration into a key fob or a smart card. The system can be activated by either pulling the door handle or by using a push button transponder. Due to the inductive coupling between the transponder and the vehicle mounted antennas, the vehicle door or trunk opens on successful verification as if there were no locks. Additionally, inside the vehicle, the transponder can be used as a far range immobiliser. The electronic door latch system utilises electronically controlled latches. Symmetrical housing of the electronic latch (E-latch) and the absence of a mechanical connection to the actuators enable the latch to be used not only for the left and right side doors but also for trunk applications. The locking pawl of the E-latch is controlled by an electric motor and the functionality is entirely software dependent."
Design and Development of a Generic Door Hardware Module Concept,"This paper documents the design methodology, part performance, and economic considerations for a generic hardware module applied to a front passenger-car door. Engineering thermoplastics (ETPs), widely used in automotive applications for their excellent mechanical performance, design flexibility, and parts integration, can also help advance the development of modular door-hardware systems. Implementation of these hardware carriers is being driven by pressures to increase manufacturing efficiencies, reduce mass, lower part-count numbers, decrease warranty issues, and cut overall systems costs. In this case, a joint team from GE Plastics, Magna-Atoma International/Dortec, and Excel Automotive Systems assessed the opportunity for using a thermoplastic door hardware module in a current mid-size production vehicle. Finite-element analysis showed that the thermoplastic module under study withstood the inertial load of the door being slammed shut at low, room, and elevated temperatures."
Sound Quality of Impulsive Noises: An Applied Study of Automotive Door Closing Sounds,"This paper discusses four general attributes which quantify the character of an impulsive sound event. These attributes include the time duration, amplitude and frequency content of the impulsive noise. A three dimensional plot relating time, frequency and amplitude have been developed for the presentation of the measured data. This format allows graphic illustration of the noise event, providing fast interpretation and communication of the measured sound. Application of this methodology to the sound of an automotive door closing event is presented here. Representative door closing sound events are analyzed, with correlation presented between the attributes above to dynamic events of the physical hardware within the door and vehicle systems. Modifications of the door-in-white, internal door hardware, seal systems and additional content are investigated for their effect on the sound quality of the door closing event. Finally, recommended values for these attributes are presented. In general, a pleasing door closing sound event will be developed if the stated values are obtained. Furthermore, general insight is also provided that would indicate how directional changes to these attributes may allow customization of the door closing sound event to achieve a desired sound quality."
Sound Transmission Analysis of Vehicle Door Sealing System,"A finite element-based acoustic-structure interaction analysis tool has been developed to determine the noise transmission loss characteristics of door seal systems. This tool has been applied to determine the effects of the individual parameters, such as seal material density, seal constitutive model, separation distance between seal layers, external cavity shape, and seal prestress field, on noise transmission characteristics. Our findings indicate that the external and internal cavity shapes, seal material density, and deformed seal geometry are the key factors affecting the noise transmission through seal system. Increasing seal material density decreases the resonance frequencies and increases the overall sound transmission loss. Changing the separation distance between seal layers changes the sound transmission characteristics without changing the compression load deflection behavior of the seal system. Moving the resonant frequencies to desired frequency regions, we can reduce seal system contribution to the vehicle interior noise level. The nature of the resonance frequencies of this coupled system have also been determined. This analysis tool was applied to determine the noise transmission characteristics of a vehicle door seal system, and the seal system contribution to the vehicle interior noise level."
A Field Evaluation of the S-1 Pedestrian Guard: Transit and Shuttle Bus Applications,"The need to reduce the injury to pedestrians that are run over or pinned beneath a bus is an ongoing concern for transit authorities and other operators. Occasionally, a pedestrian will be run over by the right rear wheel while exiting the rear door. This accident occurs in various scenarios such as when people exit the bus and become entangled in the door grab bars, or when they fall between the curb and the bus while it approaches or departs. With all scenarios, the S-1 Gard acts similar to a cow catcher, pushing the fallen pedestrian out and away from the rear tire. This paper will: outline various incident scenarios, evaluate the S-1 Gard's performance in a city environment, review installation of the guard as well as its maintenance requirements. The purpose of this paper is to bring to the attention of transit authorities and shuttle operators the overall value of this device."
Performance Improvement in Leak Noise Reduction,"One of the most important quality required for luxury vehicle is quieter cabin. Up to the present, for its improvement, various countermeasures have been carried out. For example, additional weather-strips were added around door for noise reduction and quieter engines were developed. But, with all these performance improvements, local leak noise becomes major remaining. In order to achieve quieter vehicles, the noise has to be stopped by every possible means. In this report, performance improvement in noise reduction is studied by connecting both ends of inner belt weather-strip and glass run. And the influence of connecting portion for glass sliding durability is evaluated."
Development and Application of Laser Scanning Method to Automotive Component Manufacturing,"The majority of current measurement methods in the manufacturing arena use coordinate measurement machines (CMM) and special gages with fixtures. The use of CMM's for offline metrology is prevalent throughout the manufacturing community, however the time required to inspect a part is sometimes prohibitive. The special low cost gages open the door to operator error and in most cases it cannot capture more than few measurements at once. Automated laser scanning equipment was selected to evaluate the possibility of reduced inspection as well as for global quality feedback. Although many laser scanning methods and applications are available in the market today, very little is understood with regards to its capabilities and its use in the automotive manufacturing arena particularly for the inspection of large parts. This paper explores the methodology one can use to apply such devices to improve upon current quality methods for both large and small automotive parts."
Surface Finishing Compression Molding (SFC): A Comparative Cost Study for Paint vs. Paint Film Finishing,"New technologies are required to sustain an industrial society. Their fragile early life must be nurtured by the risk takers in the beginning stages of development for new technologies to survive. In the automotive industry, new technologies that focus on reduced cost, reduced pollution and/or reduced energy consumption are being carefully evaluated. The Valyi Surface Finishing Compression Molding (SFC Molding®) process addresses all three issues1,2. This process is in the early stage of development. Large, thermoplastic, exterior panels (door/hood size) have been made on commercial equipment to demonstrate general feasibility but there are no “show me” production parts for the risk averse. In the absence of production case studies, an investor (licensee candidate) must examine the potential benefits of the process relative to the state-of-the-art technology. This paper examines an approximation of the cost to produce a major exterior panel (roof) by SFC molding versus conventional steel and paint."
A Study of Occupant Ejection Mitigation During Rollovers for Front Row Occupants,"As a part of its ejection mitigation research, the National Highway Traffic Safety Administration (NHTSA) has proposed a linear impact test that uses a featureless head-form to impact a vehicle's side windows' daylight opening at various positions. The test measures the excursion of the head-form beyond the plane of the window glazing. The intention is to evaluate the ability of a vehicle's ejection mitigation countermeasures, such as the curtain airbag or other vehicle features, to manage the impactor energy and limit excursion. However, at this time NHTSA has not yet established the performance criteria for the excursion. Additionally, there is no clear agreement on the energy level to be used for ejection mitigation testing. The agency has considered three energy levels for the head-form impact: 178, 280, and 400 Joules [ 9 ]. This paper discusses the results from computer modeling used to study an ejection representative energy level that can be employed for evaluating ejection mitigation systems. Additionally, the authors will present a parameter study in which the stiffness of a curtain airbag has been optimized considering both the NHTSA's ejection mitigation research test method as well as side impact performance."
"A FE Based Procedure for Optimal Design of Damping Package, with Presence of the Insulation Trim","Typically, in the automotive industry, the design of the body damping treatment package with respect to NVH targets is carried out in such a way to achieve panel mobility targets, within given weight and cost constraints. Vibration mobility reduction can be efficiently achieved thanks to dedicated CAE FE tools, which can take into account the properties of damping composites, and also, which can provide their optimal location on the body structure, for a minimal added mass and a maximized efficiency. This need has led to the development of different numerical design and optimization strategies, all based on the modeling of the damping composites by mean of equivalent shell representations, which is a versatile solution for the full vehicle simulation with various damping layouts. However, these approaches, which can estimate correctly the beneficial vibration effect of damping pads application on the vehicle body, address the body NVH target with no consideration of the impact that the presence of the insulation on body panels can have on the final vibration result. On the other hand, the efforts carried out in the last years for FE implementations of Biot's system of equations have led to simulation methods at vehicle level, which can take into consideration the dynamical behaviour of porous materials and which allow including in an efficient and flexible way sound package parts into vehicle FE models used for NVH analyses. This paper presents a FE-based procedure, thanks to which it is possible to design the optimal damping lay-out with respect of panel mobility targets, while taking into account the presence of the insulation part on body panels. In a first section a design methodology for damping layout is presented. This method, that is completely integrated in Nastran, is able to provides the ranking and vibration pattern of the vehicle panels with highest mobility for a given frequency range and set of loads in order to maximize the effect of the damping treatment. Then the problem of the influence of the acoustic treatment on the panel vibrations has been addressed. The proposed solution is represented by an implementation in MSC/Nastran of the Biot-Allard theory for porous media. This procedure allows a smart coupling of structural FE model with a FE boundary representation of the acoustic part. In the last section, the benefits of the joined use of the two techniques are highlighted by mean of their application on a simple test case as well as on a full-vehicle."
Electromagnetic Compatibility of Conductive Heat Reflecting Automotive Windows,One of the challenges of automotive designs which utilize heat reflecting glazing is the conductivity of the reflective coating. Significant attenuation of electromagnetic energy occurs when devices which send or receive signal through the glazing are mounted on or very near heat reflecting windows. A number of methods are available to maintain electromagnetic compatibility and the function of these and other devices in the passenger compartment which communicate with devices outside of the vehicle.
Helmholtz Resonators Acting as Sound Source in Automotive Aeroacoustics,"Helmholtz-resonators are discussed in technical acoustics normally in conjunction with attenuation of sound, not with amplification or even production of sound. On the other hand everybody knows the sound produced by a bottle, when someone blows over the orifice. During the investigation of the sound produced in body gaps it was found that the underlying flow physics are closely related to the Helmholtz-resonator. But different from the typical Helmholtz-resonator generated noise – as for example the blown bottle or, from the automotive world, the sun roof buffeting – there is no fluid resonance involved in the process. For body gaps the random pressure fluctuation of the turbulent boundary layer is sufficient to excite the acoustic resonance in the cavity. The sound generation is characterized by a continuous rise in sound pressure level with increasing velocity, the rise is proportional to U with varying exponents. It will be shown that the fluid resonance is shifted to much higher velocities than one would expect from Rossiters feedback model. This is the reason that it can not be found in body gaps. Nevertheless even without fluid resonance the body gaps represent the most important noise source for modern automobiles. A vehicle is much more silent in the interior if all gaps are closed as if, for example, the wing mirrors are removed and the A-Pillar-radius is doubled. The shift of the fluid resonance to higher velocities mentioned above is associated with a reduced transport velocity for vortices over small orifices. Experimental evidence will be shown that this transport velocity is dramatically reduced for orifices buried under a thick turbulent boundary layer."
Scaling Laws in Automotive Aeroacoustics,"Scaling laws - for example the variation of sound pressure with wind speed - are a key to the physical understanding of aeroacoustic phenomena. Aeroacoustics in Automotive applications differs from other fields of aeroacoustics: It is limited to low Mach numbers, the flow field is dominated by separated flows and the radiation into the far field is typically not of primary interest. On the other hand there are of course many common problems and findings shared with other fields in aeroacoustics. Therefore it is important to identify common areas with other, probably more advanced directions in aeroacoustics. But this has to be done without forgetting the practical demands of automotive application. Main sources for interior wind noise in vehicles are leakage noise, cavity noise and the noise generated by separated flows at the outer surface. All three of these noise sources will be investigated in this paper. Of special interest will be the dependence on the wind velocity. It will be shown that three different exponents (U4, U6 and U8), corresponding in aeroacoustics to monopole, dipole and quadrupole noise, can be present in a single source."
Time - Frequency Analysis Techniques Applied to Automotive Noise and Vibration Signals,"Automotive stationary noise and vibration signals are normally analyzed using Fourier methods. However, many noise and vibration signals are non-stationary (transient or time-varying). In those situations, the time characteristics of the signals can be lost using standard Fourier methods. Lately, time-frequency (TF) analysis methods have become more popular and are applied in many different areas of NVH (Noise, Vibration, and Harshness) in order to preserve the time-frequency information. The objective of this paper is to present some of the different time-frequency analysis tools, such as the Short Time Fourier transform (spectrogram), the Gabor Transform, the Wavelet transforms (scalograms), and the Wigner-Ville Distribution. Examples of application of these techniques to automotive non-stationary noise and vibration signals are presented."
Noise Source Localization on Washing Machines by Conformal Array Technique and Near Field Acoustic Holography,"The acoustic emission of a washing machine has been deeply studied by comparing three different techniques, which are: - conventional acoustic intensity, - planar near-field acoustic holography and - conformal array technique based on the Helmotz Equations Least Squares method. These techniques have been used to measure the front of a washing machine, i.e. the more critical side from the acoustic comfort point of view in the working environment. The acoustic intensity measurement has been taken as reference for the comparison of the two other techniques. The sound intensity probe has been scanned over a grid of several discrete positions and the acoustic intensity and pressure on the measurement plane have been determined. For both the conformal and planar near-field acoustic holography techniques an antenna of 30 microphones has been employed scanning over several positions in order to cover the entire washing machine front with a spatial resolution of 2.5 cm (maximum frequency 13720 Hz). Advantages and limitations of the noise source location techniques have been examined thoroughly."
Experimental Investigation into Friction Induced Noise of Automotive Wiper System,"The test is carried out to examine the vehicle interior noise, windscreen vibration and wiper blade vibration induced by wiper friction, under the combination conditions with various wiping speed and windscreen wetness. The noise's time-frequency characteristics, influence factors and noise source were approached by means of time domain, frequency domain and time-frequency domain analysis. The results indicated that wiper noise can be classified into reversal noise and wiping noise. The reversal noise is characterized by impulsive noise, and wiping noise is featured by wide-band noise with harmonic components. The nature of both types of noises is strongly affected by the windshield wetness; however, it is far less affected by the wiping speed. The wiping noise is mainly resulted from lateral and vertical vibration of wiper blades. Nevertheless, the wiping noises under wet and half-dry conditions are respectively caused by the wiper blade vibration of driver side and that of co-driver side."
Aeroacoustics Predictions of Automotive HVAC Systems,"Acoustics comfort is a key point for the ground transportation market and in particular in the automotive area. A significant contributor to the noise levels in the cabin in the range 200Hz to 3000Hz is the HVAC (Heating, Ventilating, and Air Conditioning) system, consisting of sub-systems such as the air intake duct, thermal mixing unit, blower, ducts, and outlet vents. The noise produced by an HVAC system is mainly due to aeroacoustics mechanisms related to the flow fluctuations induced by the blower rotation. The structure borne noise related to the surface induced vibrations and to the noise transmission through the dash or plastic panels may also contribute but is not considered in this study. This study presents a digital approach for HVAC aeroacoustics noise predictions related to the ducts and outlet vents. In order to validate the numerical method flow and acoustics measurements are performed on production HVAC systems placed in an anechoic room. The flow is generated using a fan located outside the room and a muffler is used to create a silent incoming flow. The dependency between the volume flow rate and the noise levels is investigated together with the effect of the outlet vents on the aeroacoustics mechanisms. The aeroacoustics simulations are performed using a time explicit, unsteady and compressible method in which flow and acoustics are calculated at the same time. The numerical results are compared to the experimental ones and certain analyses, not easily accessible through measurements, are provided. In particular, duct mode behavior and the influence of the outlet vents on the acoustic radiation are highlighted. The numerical predictions are shown to correlate reasonably well to the test measurements, and the developed method can be used during the vehicle development process to evaluate and optimize the aeroacoustics performance of the HVAC system."
Attenuation of Vehicle Noise using Different Trunk Insulation Systems,Attenuation of noise from the rear of a vehicle was evaluated for different trunk insulation systems using a combination of poro-elastic material modeling and a full vehicle SEA model. The model considered the interaction between the trunk and the passenger cabin. The sound absorption coefficients and acoustic impedance for each of the material systems used in the trunk were measured and the poro-elastic Biot properties were calculated to define the acoustic treatments in the SEA model. Several levels of acoustical treatment for the trunk were studied ranging from a trunk with no decorative liner to a trunk with a liner and maximum acoustical treatment. The results show the contribution of the trunk material in reducing cabin noise for different levels of noise originating at the rear of the vehicle. These results demonstrate the value of combining poro-elastic material modeling and SEA models for selecting efficient material systems early in a vehicle design. They also highlight vehicle designs that require acoustically tuned trunk material to prevent compromises in the overall NVH performance.
"Vehicle Noise, Vibration, and Sound Quality","This book gives readers a working knowledge of vehicle vibration, noise, and sound quality. The knowledge it imparts can be applied to analyze real-world problems and devise solutions that reduce vibration, control noise, and improve sound quality in all vehicles—ground, aerospace, rail, and marine. Also described and illustrated are fundamental principles, analytical formulations, design approaches, and testing techniques. Whole vehicle systems are discussed, as are individual components. The latest measurement and computation tools are presented to help readers with vehicle noise, vibration, and sound quality issues. The book opens with a presentation of the fundamentals of vibrations and basic acoustic concepts, as well as how to analyze, test, and control noise and vibrations. The next 2 chapters delve into noise and vibrations that emanate from powertrains, bodies, and chassis. The book finishes with an in-depth discussion on evaluating noise, vibration, and sound quality, giving readers a solid grounding in the fundamentals of the subject, as well as information they can apply to situations in their day-to-day work. This book is intended for: •Upper-level undergraduate and graduate students of vehicle engineering •Practicing engineers •Designers •Researchers •Educators"
International Space Station United States Operational Segment Crew Quarters On-orbit vs. Design Performance Comparison,"The International Space Station (ISS) United States Operational Segment (USOS) received the first two permanent ISS Crew Quarters (CQ) on Utility Logistics Flight Two (ULF2) in November 2008. As many as four CQs can be installed in the Node 2 element to increase the ISS crew member size to six. The CQs provide crew members with private space that has enhanced acoustic noise mitigation, integrated radiation-reduction material, communication equipment, redundant electrical systems, and redundant caution and warning systems. The rack-sized CQ system has multiple crew member restraints, adjustable lighting, controllable ventilation, and interfaces that allow each crew member to personalize his or her CQ workspace. The deployment and initial operational checkout during integration of the ISS CQ to Node 2 is described in this paper. On-orbit to original design performance is also compared for the following key operational parameters: interior acoustic performance, airflow rate, temperature rise, and crew member feedback on provisioning and re-straint layout."
International Space Station USOS Crew Quarters Development,"The International Space Station (ISS) United States Operational Segment (USOS) currently provides a Temporary Sleep Station (TeSS) as crew quarters for one crewmember in the Laboratory Module. The Russian Segment provides permanent crew quarters (Kayutas) for two crewmembers in the Service Module. The TeSS provides limited electrical, communication, and ventilation functionality. A new permanent rack sized USOS ISS Crew Quarters (CQ) is being developed. Up to four CQs can be installed into the Node 2 element to increase the ISS crewmember size to six. The new CQs will provide private crewmember space with enhanced acoustic noise mitigation, integrated radiation reduction material, controllable airflow, communication equipment, redundant electrical systems, and redundant caution and warning systems. The rack sized CQ is a system with multiple crewmember restraints, adjustable lighting, controllable ventilation, and interfaces that allow each crewmember to personalize their CQ workspace. Providing an acoustically quiet and visually isolated environment, while ensuring crewmember safety, is critical for crewmember rest and comfort to enable long term crewmember performance. The numerous human factor, engineering, and program considerations during the concept, design, and prototyping are outlined in the paper."
Development of an Automatic Windshield Defogging System,The development of an automatic defogging system using an accurate windshield humidity sensor and the existing HVAC hardware is described herein. Improved cabin temperature control and forward visibility for the driver was achieved using a sophisticated automatic defogging strategy integrated into the Automatic Temperature Control microprocessor. Laboratory tests were conducted under various weather conditions and test modes using a climate wind tunnel and field tests were conducted in North America The automatic defogging system worked well in all cases
Modelling of the Combustion Influence on Diesel Engines Noise Level for MAR-I Applications,"Since January 2015, Brazil put into effect the PROCONVE/MAR-I (Programa de Controle da Poluição do Ar por Veículos Automotores para Máquinas Agrícolas e Rodoviárias), which drives the country to the same stringent emissions standards used by the American (EPA Tier III) and European (Euro Stage IIIA) markets. As a result, new pollutants and noise emissions levels were established and although very important for the society health, this issue (noise) has been left behind in this kind of vehicle. Therefore, an extremely challenging target has to be pursued, regarding the current political and economical situation and also the resources availability to achieve those targets. The present work investigates the influence of the noise generated during the combustion process in MAR-I engines by modeling the calibration parameters, which allows to identify the contribution of the combustion in the global engine noise and possibly reducing it and hence the product reckoned costs."
Vibroacoustic Transfer Function Study in the Design of Vehicle Suspensions,"Noise, vibration and Harshness in the automotive industry became important mainly because the development of modern automobiles and the increased of customer demands for quieter vehicles and with comfortable vibration levels. The sources of vibration and noise inside the vehicle are caused by the engine, tires, transmission systems, suspension, air conditioning, among others. In this work, vibroacoustic transfer function is obtained to analyze the internal noise in two sport utility vehicle with distinctive silhouette. Furthermore, it was analyzed the influence of elastomeric bushings rigidity of the damper in reducing internal noise and vibration and the effect of adding mass in some framework positions for attenuation of vibration peaks due to structural resonance. In the physical tests, it was used accelerometers installed on top of the fixing bracket of the damper and in specific positions in the vehicle body, a microphone installed on the right ear position of the passenger of the right rear seat and an impact hammer used to excite the system to obtain the vibroacoustic transfer function. Temporal measurements are carried out with vehicles on irregular track to a constant speed. The data are processed and analyzed in the frequency domain. The results show that the use of vibroacoustic transfer function is important for understanding and analysis of the noise within the vehicle cabin and that changes in the stiffness of the dampers bushings can reduce noise within the vehicle. Furthermore, the adding of mass to the structure was efficient to attenuate the vibration due to structural resonance."
Practical Approaches for Detecting DoS Attacks on CAN Network,"Some of the recent studies reveal that it is possible to access the in-vehicle networks and inject malicious messages to alter the behavior of the vehicle. Researchers have shown that, it is possible to hack a car’s communication network and remotely take control of brake, steering, power window systems, etc. Hence, it becomes inevitable to implement schemes that detect anomalies and prevent attacks on Controller Area Network (CAN). Our work explores the complete anomaly detection process for CAN. We cover the techniques followed, available tools and challenges at every stage. Beginning with what makes CAN protocol vulnerable, we discuss case studies about attacks on CAN with major focus on Denial of Service (DoS) attack. We analyze the pattern of normal CAN messages obtained from real vehicle, along with patterns of simulated attack data using different methods/tools. The work in this paper presents a statistical data analysis based machine learning algorithm with two approaches “time-based” and “message-based” to detect DoS attack on CAN bus. Comparative analysis of observations and accuracy results are highlighted. The average accuracy obtained for “time-based” approach is 81% while that for “message-based” is 80%."
CFD/CAE Combinations in Open Cavity Noise Predictions for Real Vehicle Sunroof Buffeting,"Though some practitioners consider the simulation process for sunroof and side window buffeting to be mature, there remain considerable uncertainties and inefficiencies as how in predictive methodologies to account for interior panel flexibility, vehicle structural stiffness, seals leakages and interior materials surface finish. Automotive OEMs and component suppliers rightly target flow simulation of open sunroofs and passenger windows with a view to reducing the severely uncomfortable low-frequency booming disturbance. The phenomenon is closely related to open cavity noise experienced also in other transportation sectors; for example in Aerospace, landing gear and store release cavities, and in Rail Transportation, cavities for HVAC intakes and the bogie environment. Recent studies published by the author demonstrate that the uncertainties can be correctly quantified by modeling. This publication defines a hierarchy of CFD/CAE based methods which overcome many of the a-posteriori tuning of simulations based on experiment, and considerably improve the predictive nature and efficiency of the simulation process. The methods range from fully deterministic simulations to phenomenological models requiring standard experimental pre-qualifications of the acoustical response of the system. The former involves CAE-coupling of CFD (Computational Fluid Dynamics) to CAA (Computational Aeroacoustics) and to CSM (Computational Structural Mechanics). The latter incorporates new correlation models published here for the first time."
Dynamic Alert Generation Technology for Health & Usage Monitoring Systems,"Current alert setting methodologies based on setting defect detection alert thresholds for vibration and other Health & Usage Monitoring Systems (HUMS) indicators have many limitations, principally there is necessarily a compromise to be achieved between the true negative and false positive diagnostic metrics. This is true for all alert detection techniques from fixed thresholds through to Support Vector Machines. In this paper we describe techniques, validated using helicopter HUMS data, which do not invoke this compromise and independently minimise both the true negative and false positive rates. This paper will also demonstrate how the alert processing can be made more robust and overcome the problems introduced by HUMS data being both non-stationary, non-ergodic i.e. characteristics that change both with time and from platform to platform. Two techniques utilised in the CFAR-Autotrend proprietary alert detection technology are described; a) The Constant False Alarm Rate technique for setting thresholds based on signal amplitude and detecting level changes b) The Box- Car technique for the automatic detection of local trends. These techniques produce alerts that are based on a significant change in local, not global, conditions in the data stream and are not based on an a priori model of the statistics of the signal. The performance of these techniques on real world HUMS generated vibration data and the engineering of the processes to automatically produce reliable and robust alerts are reviewed. False positives have been verified to be reduced to be less than 10% of true positives; a level where the diagnostics process becomes robust. The sensitivity to defects is improved to a level where the true negative rate has been reduced to a level where the diagnostic processes can be relied on and the prognostic interval becomes reliable. The consequential impact of this level of performance on HUMS dynamic alert processing is assessed. The automation of alert processing breaks the link between the number of aircraft fitted with HUMS and the manpower required to process the data. More importantly it will permit the scarce resource of HUMS specialists trained to diagnose defects to be concentrated on that task, not dissipated processing false alerts. For the future the Remaining Useful Life (RUL) realised from the increased sensitivity of the technique is at a magnitude where the benefits promised by Condition Based Maintenance can become a reality."
Direct Aeroacoustics Predictions of Automotive HVAC Systems based on Lattice Boltzmann Method,"The demand for low noise level in vehicle cabin continues to rise lately. In particular, noise generated by eco-friendly cars such as hybrid and electric ones tends to become lower and lower. In this market environment, the noise contributions caused by HVAC systems are also increasing. Therefore, it becomes increasingly important to accurately predict noise generated by HVAC systems and analyze the noise sources and resolve the noise issue. In this study, direct acoustics prediction approach based on Lattice Boltzmann Method is applied to predict the flow-induced noise from HVAC systems including blower and ducts and find noise sources. In order to validate the simulation result, acoustics measurements are performed on HVAC systems in an anechoic room and the results are compared to each other. A new technique is applied to finding a noise source for a specific frequency and shows improved noise level through modifying the geometry related to noise sources detected by the simulation."
Comprehensive Hybrid Stiff Insulators Family: The Chips Urethane Contribution,"The lightweighting research on noise treatments since years tends to prove the efficiency of the combination of good insulation with steep insulation slopes with broadband absorption, even in the context of bad passthroughs management implying strong leakages. The real issue lies more in the industrial capacity to adapt the barrier mass per unit area to the acoustic target from low to high segment or from low petrol to high diesel sources, while remaining easy to manipulate. The hybrid stiff insulator family can realize this easily with hard felts barriers backfoamed weighting from 800 g/m2 to 2000 g/m2 typically with compressions below 10 mm. Above these equivalent barrier weights and traditional compressions of 7 mm for example, the high density of the felts begins to destroy the open porosity and thus the absorption properties (insulation works anyway here, whenever vibration modes do not appear due to too high stiffness…). The felt costs begin to be critical for these intermediate weights above 2000 g/m2 as well. From 2000 g/m2 up to 3000 g/m2 or 3500 g/m2 equivalent barriers, the use of a traditional intermediate heavy layer is still not relevant from a process and cost point of view (ABA - Absorber/Barrier/Absorber systems). An original way to circumvent the issue consists in using a double porosity material like compressed chips urethane bound with bicomponent thin fibers. Airflow resistivities and porosities remain high while reasonable even at high compressions and thus deliver very good absorption, while being stiff enough to allow mass-spring like insulation slopes, as well as not too stiff in order to avoid bad modal resonances. The acoustic performance of this unconventional hybrid stiff insulator solution will be discussed with poro-elastic finite element modeling compared to measurements and to other hybrid stiff or ABA existing solutions of the same mass per unit area."
A Subjective Evaluation Method for Sound Insulation of Vehicle Body in Reverberation Room and an Objective Prediction Model,"A subjective evaluation method for the air-borne sound insulation of vehicle body in reverberation room is developed and the correlation between the subjective preference and objective noise reduction level (NRL) is investigated in this paper. The stationary vehicle's interior noise is recorded by using a digital artificial head under a given white noise excitation in the reverberation room, which demonstrates more credible than those in traditional road test methods. The recorded noises of six different vehicles are replayed and evaluated subjectively by 22 appraisers in a sound quality room. The paired comparison scoring method is employed and the check and statistic methods for the subjective scores are introduced. The subjective preference is introduced and calculated by the statistics and normalization of the effective scores, which can indicate an overall preference ranking of all the six vehicles numerically. Furthermore, an objective prediction model is established based on the correlation analyses and linear regressions. The subjective preference is proved to be attributed to the average NRL in 2k-5kHz frequency range only. The subjective evaluation method and the prediction model provide the guidance for the evaluation, prediction, target setting and optimization of the vehicle sound insulation."
Improved Full Vehicle Finite Element Tire Road Noise Prediction,"This paper presents the application to full vehicle finite element simulation of a steady state rolling tire/wheel/cavity finite element model developed in previous work and validated at the subsystem level. Its originality consists in presenting validation results not only for a wheel on a test bench, but for a full vehicle on the road. The excitation is based on measured road data. Two methods are considered: enforced displacement on the patch centerline and enforced displacement on a 2D patch mesh. Finally the importance of taking the rotation of the tire into account is highlighted. Numerical results and test track measurements are compared in the 20-300 Hz frequency range showing good agreement for wheel hub vibration as well as for acoustic pressure at the occupant’s ears."
An Optimal Camera Monitor System (OCMS) to Improve the Visibility Performance and Safety of Commercial Vehicles and Trucks,"Similar to Passenger Vehicles (PV), Commercial Vehicles and Trucks (ComVecT) use standard rearview mirrors to improve the visibility of the surrounding environment and facilitate a safer maneuvering of large vehicles. Standard rearview mirrors used in ComVecT are large and flat to cover outside areas as specified in theFMVSS 111 standard, or other requirements like ECE-R46. In addition, ComVecT are also equipped with optional mirrors with different Field of View (FoV), such as wide angle, look-down cross proximity, and front mirrors. These optional mirrors cover wider or specific areas around the vehicle which might not be possible otherwise with standard mirrors only. While these mirrors tend to enhance the visibility around the truck, they create undesirable blind zones to the driver. These blind zones can be gaps between the direct vision through the windows and indirect vision provided by the mirror. These can also be invisible areas occluded by the vehicle structure and hidden to the driver. Or, these can be obstructed areas concealed behind the mirror. In this paper, we demonstrate the feasibility and design of an Optimal Camera Monitor System (OCMS) to ideally eliminate the blind zones around the ComVecT with the goal of enhancing the driver visibility. We show that blind zones occur naturally due to the vehicle structure and large dimensions; number of mirrors used and mirror sizes. The optimal design takes into consideration not only the position, FoV, and resolution of the camera, but also the position, size, and resolution of the display inside the vehicle. The optimal design takes also into consideration human constraints like driver position and visual acuity of the human eye."
Interior Noise Design of a Light Rail Vehicle Using Statistical Energy Analysis,"This paper addresses the NVH design of a light rail vehicle whose maximum allowable interior SPL levels at certain speeds are regulated and may vary between countries, states, and cities. The objective of this study was to predict sound pressure levels (SPL) at several interior locations across a wide range of frequencies and estimate if the current design configuration will meet the noise level limits. Statistical Energy Analysis (SEA) was used to predict interior SPL and to understand and rank the various noise contribution paths and give a better understanding of the physics of transmission and what types of design changes are most effective to reduce the overall interior SPL to meet targets. A typical light rail vehicle is composed of a frame-like structure covered by lightweight panels and with interior panels that are increasingly made from composites, sandwich, laminated, or honeycomb materials or extruded panels. These lightweight structures made from materials that have previously been used primarily in aerospace applications have modal characteristics and transmission properties that require more advanced modeling than for simpler monolithic panels. Evaluation of the dominant noise transmission paths from the dominant sources allows sensitivity studies to evaluate which noise paths are the best candidates for improvement to overall vehicle NVH and which parts may be candidates for cost and weight reduction without significant degradation of the acoustic performance. This paper describes the motivation for this study and the details of the light rail vehicle construction. The SEA modeling approach is discussed, including the modeling of the structures and the main contributing sources. The contribution path ranking and the interior SPL predicted by the SEA model at several target locations are presented and compared to measured interior SPL data. Conclusions about the results and recommendations for future work are given."
Application of Near-field Acoustic Holography to Low Temperature Engine Start-up Noise Issue Resolution,"An issue of engine squealing in low temperature range (around −25°C) right after start-up emerged for a significant number of vehicles in a vehicle program. The earlier effort had focused on typical common culprits such as the pulley-belt systems etc. However, much effort, by subjective listening and guestimating hardware replacement, yielded no fruitful results for more than a year. The application of near-field acoustic holography on top of the engine in a climate chamber quickly identified several noise source locations. Further noise source identification effort on top, front and left side of the engine pinpointed the top three noise source locations: the idler pulley and water pump on front, the air compressor on right side, and the air intake throttle on top. Then a series of experiments were subsequently conducted, leading to a conclusion that the idler pulley was the source of the issue. Finally, investigation of the pulley system confirmed that the insufficient lubricating capacity at low temperature was the root cause. By switching to a type of lower base oil viscosity lubricating grease characterized by lower rotation torque in cold temperature conditions, the issue was successfully resolved."
MMLV: NVH Sound Package Development and Full Vehicle Testing,"The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The Mach-1 vehicle design, comprised of commercially available materials and production processes, achieved a 364 kg (23.5%) full vehicle mass reduction, enabling the application of a 1-liter 3-cylinder engine resulting in a significant environmental benefit and fuel reduction. This paper includes details associated with the noise, vibration and harshness (NVH) sound package design and testing. Lightweight design actions on radiating panels enclosing the vehicle cabin typically cause vehicle interior acoustic degradation due to the reduction of panel surface mass. To reduce this deficiency, an MMLV vehicle sound package development was conducted to improve NVH performance of MMLV with ultra-light weight sound package technologies. The project goal was to improve acoustical performance of MMLV by 2 dB without increasing the total sound package weight of “Vehicle A” which is the baseline vehicle for MMLV. This paper presents the lightweight sound package development process for MMLV as well as the full vehicle NVH test results in the high frequency range of 200-10000 Hz. Floor damping treatment strategy and body NVH test results in the low frequency range are also discussed. Full vehicle SEA (Statistical Energy Analysis) simulations are used to evaluate and guide the design and development of MMLV sound package. The final MMLV vehicle sound package design improves the vehicle's engine noise reduction (ENR) by 3.3 dB and improves the front tire patch noise reduction (TPNR) by 1.2 dB without increasing the baseline sound package weight."
A Virtual ECU and Its Application to Control System Analysis - Power Window System Demonstration,"A virtual power window control system was built in order to look into and demonstrate applications of microcontroller models. A virtual ECU simulated microcontroller hardware operations. The microcontroller program, which was written in binary digital codes, was executed step-by-step as the virtual ECU simulation went on. Thus, production-ready codes of ECUs are of primary interest in this research. The mechanical system of the power window, the DC motor to lift the window glass, the H-bridge MOSFET drivers, and the current sensing circuit to detect window locking are also modeled. This means that the hardware system of the control system was precisely modeled in terms of mechanical and circuit components. By integrating these models into continuous and discrete co-simulation, the power window control system was analyzed in detail from the microscopic command execution of the microcontroller to the macroscopic motion of the window mechanism altogether. The minute microcontroller operation in a few nanosecond time span and slower window lifting were observed in the same time traces. Obviously, the accuracy and the simulation time of the co-simulation were a trade-off. In this paper the techniques to deal with the causes of the timing errors in co-simulation were discussed. Possible use of this technology includes detailed analysis of control operation and verification of the fail-safe response to component failures. As the co-simulation includes both the control system hardware in component level and the control software in execution format, components failures are easily injected in any level. This work was one of the outcomes of the vECU-MBD WG (Virtual ECU Model-Based Development Working Group) in Japan."
Anti-Pinch Mechanism for Power Window,"New generation automobiles are equipped with power windows which eases the passenger’s effort in moving the vehicle windows up and down. Many of them are stuffed with advanced features like automatic up/down option for ensuring functionality with a single press of the switch. Even though it adds comfort to driver & passenger, inadvertent use of power window can be fatal if a person’s body part gets trapped inside. An effective solution for this problem is anti-pinch mechanism, which releases the object safely just when it gets trapped. It detects the object trapped and immediately moves the window down so that trapped object will get released easily. The anti-pinch algorithm used in this project is based on the “Method of Monitoring Movable Element”, method monitor traveling distance of a power window pane. In order to achieve this different from conventional techniques we are using Ultrasonic sensor. The anti-pinch technology of power window has to meet standards issued by EU and United States. The maximum force a power window is allowed to exert on any object is 100N. Compliance with this limit must be monitored and enforced in a range of 4mm to 100mm from the top window frame, which is successfully meet by prototype designed. The goal of this project is to provide ultimate protection from power window injuries by implementing this simple & effective safety system to vehicles which are already running on road. Compactness & independent functionality ensures great compliance of this accessory with existing power windows."
Windows Opening Influence on the Drag Coefficient of a Hatchback Vehicle,"Aerodynamics plays a key role in nowadays vehicle development, aiming efficiency on fuel consumption, which leads to a green technology. Several initiatives around the world are regulating emissions and efficiency of vehicles such as EURO for European Marketing and the INOVAR Auto Project to be implemented in Brazil on 2017. In order to meet requirements in terms of performance, especially on aerodynamics, automakers are focusing on aero-efficient exterior designs and also adding deflectors, covers, active spoilers and several other features to meet the drag coefficient. Usually, the aerodynamics properties of a vehicle are measured in both CFD simulations and wind tunnels, which provide controlled conditions for the test that could be easily reproduced. During the real operations conditions, external factors can affect the flow over the vehicle such as cross wind in open highways. The aerodynamic behavior of the vehicle can also be affected by the influence of the user such as by opening the windows in order to cool down the cabin, which is the main topic of this paper. In this work, 12 different window-opening combinations are presented and the drag values compared with a baseline model, considering fully closed windows. The study was conducted using CFD simulations of a current production hatchback vehicle, with two passenger inside and full interior cabin representation. Results show drag increment for all presented cases, compared with baseline configuration, which also implies in fuel consumption increase. Further studies on cabin cooling effects and passenger’s thermal comfort are conducted in order to complement this paper."
Design Optimization of Vehicle Body NVH Performance Based on Dynamic Response Analysis,"Noise-vibration-harshness (NVH) design optimization problems have become major concerns in the vehicle product development process. The Body-in-White (BIW) plays an important role in determining the dynamic characteristics of vehicle system during the concept design phase. Finite Element (FE) models are commonly used for vehicle design. However, even though the speed of computers has been increased a lot, the simulation of FE models is still too time-consuming due to the increase in model complexity. For complex systems, like vehicle body structures, the numerous design variables and constraints make the FE simulations based optimization design inefficient. This calls for the development of a systematic and efficient approach that can effectively perform optimization to further improve the NVH performance, while satisfying the stringent design constraints. In the present work, an efficient method to optimize the structural dynamic response is proposed considering the low-frequency NVH performances. As a first step, to reduce computational burden, a response sensitivity analysis is performed to detect the most important variables prior to the design optimization. Then an analytical approximation model of vibration resonance peak is constructed and coupled with the adaptive simulated annealing (ASA) algorithm to replace the time-consuming finite element analysis. Subsequently, an optimization of NVH performance considering dynamic response is formulated and carried out. The methodology aims at improving the NVH behavior of body structure by simultaneously suppressing several resonance peaks. Finally, the proposed method and its process are successfully illustrated through a vehicle body example. The results demonstrate that the proposed method of incorporating response surface model with ASA algorithm is feasible and cost-efficient in solving the vibration optimization problem."
Modelling Techniques for Noise and Vibration Control of the Body and Chassis,"The basic function of a motorcycle frame is somewhat similar to that of the skeleton in the human body, i.e. to hold together the different parts in one rigid structure. One of the major benefits (for a motorcycle enthusiast) of using an advanced frame design lies in the sporty handling characteristics of the bike. A well designed frame can add to the joy of riding a motorcycle as the bike would feel more stable, effortless, and confident around corners, in straight lines and while braking. A well approved modeling [2] techniques or adequate guide line principles have to be followed while designing the body and chassis in order to achieve the vibration within control. This paper depicts a methodological right approach (guide lines) while designing the body and chassis of a two wheeler in order to control noise and vibration of the body and chassis."
Optimization of Bushing Stiffness Using Numerical Approximation Model to Improve Automotive NVH Performance,"An efficient method to determine optimal bushing stiffness for improving noise and vibration of passenger cars is developed. In general, a passenger vehicle includes various bushings to connect body and chassis systems. These bushings control forces transferred between the systems. Noise and vibration of a vehicle are mainly caused by the forces from powertrain (engine and transmission) and road excitation. If bushings transfer less force to the body, levels of noise and vibration will be decreased. In order to manage the forces, bushing stiffness plays an important role. Therefore, it is required to properly design bushing stiffness when developing passenger vehicles. In the development process of a vehicle, bushing stiffness is decided in the early stage (before the test of an actual vehicle) and it is not validated until the test is performed. If it turns out that vehicle performances are not satisfied in the test, another test with bushing changed needs to be conducted, which requires additional costs. Several tests are usually performed to identify bushings which achieve target performances. In addition, the decision of bushing stiffness is complicated since there is typically a conflict between requirements for bushing stiffness from various vehicle performances, such as ride, handling, noise, and vibration. Therefore, in the design stage, the validation of bushing stiffness is desirable to save costs of the vehicle development and ensure the performances of the vehicle. In this paper, a novel optimization methodology based on a numerical approximation model is presented. This method is used to determine optimal stiffness values of bushings in a vehicle for improving the vehicle noise. By using the method, it is found that bushing stiffness is well optimized while reducing the noise."
Characteristics of Non-Stationary Sources of Wind Noise Measured with a Surface Pressure Array,Measurements of interior wind noise sound pressure level have shown that dBA and Loudness are not adequate metrics of wind noise sound quality due to non-stationary characteristics such as temporal modulation and impulse. A surface microphone array with high spatio-temporal resolution has been used to measure and analyze the corresponding non-stationary characteristics of the exterior aero-acoustic loading. Wavenumber filtering is used to observe the unsteady character of the low wavenumber aero-acoustic loading components most likely to be exciting glass vibration and transmitting sound.
A Research on the Sound Quality Contribution of Vehicle Body Panel,"Sound quality of vehicle interior noise affects passenger comfort. In order to improve the sound quality of a micro commercial vehicle, the vehicle interior noise under different conditions such as idle, constant speeds and accelerating is recorded by using artificial head with dual microphones. The sound quality of recorded noise is evaluated in both objective and subjective ways. Physical parameters of interior noise are calculated objectively, and annoyance score is analyzed subjectively using paired-comparison method. According to the regression analyzing of the annoyance score and the physical parameters, an objective evaluation parameter of the sound quality is employed. To analyze the vehicle body panel contribution to interior noise sound quality, the location and spectrum characteristics of major panel emission noise sources are identified based on partial singular valued decomposition (PSVD) method. By investigating the contribution of each noise sources to the sound quality evaluation formula, the dominant interior noise source is determined. That provides technical support for subsequent research on improving the sound quality of vehicles."
Evaluation on the Solar Reduction Glass in an Electric Vehicle by Experimental Measurements in a Climate Chamber,"Solar energy through glass windows has an influence on the thermal environment in the cabin and thermal comfort of occupants. A medium-size electric vehicle (EV) is conducted for evaluating the performance of solar reduction glass under summer conditions in the climate chamber by experimental measurements. For this purpose, two kinds of glass are attached to the medium-size EV with different performance of solar reduction rate (IR-cut type and normal type). In this paper, two types of experimental measurements, steady state and unsteady state conditions, are conducted. Surface temperature, air temperature and electric consumption of air conditioner are measured under some conditions of air-conditioner. EHT (Equivalent Homogeneous Temperature) by thermal manikin, thermal sensation and thermal comfort by male and female subjects are also measured. Significant difference in the measured surface temperature of the instrument panel where solar radiation reaches through the glass window is found between IR-Cut glass and normal glass. In addition, one or two rank difference in the thermal comfort at the part where solar radiation reaches is found, and “hot” thermal sensation and discomfort in the female subject is much improved. Heat load of the air conditioner can be decreased by 20% from the view point of controlling the air conditioner by thermal comfort of the occupants. The solar reduction glass such as IR-cut glass has a significant influence on the thermal sensation, thermal comfort of car occupants and electric consumption of EV."
Identification of Vibro-Acoustic Coupled Modes for Vehicle,"In performing noise control design for vehicles, there is a benefit to identifying important vibro-acoustic coupled mode. The purpose of this study is “identifying the coupled mode of a vehicle through FRF (frequency response function) measurement”. A speaker which measure the internal acoustic pressure was used as a new experimental method. An acoustic input is estimated by the fluctuation of the acoustic pressure inside the speaker box. Acoustic pressures are measured by using some microphones, the vibrations of the structure are measured by using some accelerometers. Main experiment was carried out for measure the vibro-acoustic mode. First acoustic mode was identified in about 66 Hz. And structure associated mode with this mode was identified. Hence, the vibro-acoustic mode identification was carried out."
Experimental Determination of Acoustic Cavity Resonances of Vehicle Sub-Systems,"The present quiet and comfortable automobiles are the result of years of research carried out by NVH engineers across the world. Extensive studies helped engineers to attenuate the noise generated by major sources such as engine, transmission, driveline and road excitations to a considerable extent, which made other noise sources such as intake, exhaust and tire perceivable inside. Many active and passive methods are available to reduce the effect of said noise sources, but enough care needs to be taken at the design level itself to eliminate the effect of cavity resonances. Experimental investigation of cavity resonances of real systems is necessary besides the FEA model based calculations. Acoustic cavity resonance of vehicle sub systems show their presence in the interior noise through structure borne and air borne excitations. Cavity resonances for some systems e.g. intake can only be suppressed through resonators. The exact location and nature of acoustic cavity resonance needs to be found as accurately as possible to bring out the best from a resonator. Different approaches are used to excite and identify the cavity resonances depending on the operational differences of various systems. Cabin cavity modes are analyzed by arranging an array of microphones inside the cabin and exciting the cavity with help of a low frequency volume acceleration source. The cavity modes of inflated tire are analyzed by placing accelerometers circumferentially and exciting the cavity by intermittent deflation. The cavity resonances of intake system are investigated using microphones by providing excitation through a low frequency volume acceleration source. Acoustic modal analysis is carried out to identify and understand the mode shapes."
Method for Measuring and Analyzing Transient Powertrain Vibrations of Hybrid Electric Vehicles on an Acoustic Roller Test Bench,"In terms of customer requirements, driving comfort is an important evaluation criterion. Regarding hybrid electric vehicles (HEVs), maneuver-based measurements are necessary to analyze this comfort characteristic [1]. Such measurements can be performed on acoustic roller test benches, yielding time efficient and reproducible results. Due to full hybrid vehicles’ various operation modes, new noise and vibration phenomena can occur. The Noise Vibration Harshness (NVH) performance of such vehicles can be influenced by transient powertrain vibrations e.g. by the starting and stopping of the internal combustion engine in different driving conditions. The paper at hand shows a methodical procedure to measure and analyze the NVH of HEVs in different driving conditions. In order to investigate the influence of noise and vibrations by restarting and stopping the internal combustion engine (ICE) (like switching between electric and hybrid driving or the start-stop function) on the driver, acoustic and vibration measurements are performed inside the vehicle. A binaural artificial head is used to examine the acoustic effects on the vehicle interior noise. The vibration behavior is analyzed using acceleration sensors at defined measurement positions. Regarding the human perception of the NVH performance, characteristic values, related to the vibrational response of the vehicle, are needed for a vehicle evaluation. By combining the measurement data of the transient powertrain vibrations with evaluation approaches (ISO 2631-1, DIN EN 61672-1, spectrograms using Fourier transform (FFT) and subsequent psychoacoustic criteria) a frequency-dependent vibration analysis is performed. The analysis, depending on measurements on an acoustic roller test bench, supports the development of HEVs’ NVH performance, regarding the perceived driving comfort by the customer."
Analysis of Gear Rattle Noise and Vibration Characteristics Using Relative Approaches,"Noise signals of the driver’s right ear include those of engine, environment, chassis dynamometer, loaded gears and unloaded gears when they are recorded in full vehicle on chassis dynamometer in semi-anechoic room. Gear rattle noise signals of the driver’s right ear caused by unloaded gear pairs can’t be identified or quantified directly. To solve the problems, relative approaches are used to identify and quantify the gear rattle noise signals. Firstly, the rattle noise signals of the driver’s right ear are filtered by human ear characteristic functions and steady noise signals are extracted by regression and smoothing processes. The noise signals are regressed at 200ms interval in the hearing critical frequency bands and smoothed in the flanking frequencies. Then, the noise relative approaches are obtained by subtracting the steady noise signals from the filtered noise signals, which are the transient noise signals of the unloaded gear pairs inducing the rattle noise. Finally, the occurrence time, frequency and level of the rattle noise are obtained from the noise relative approaches. Through this method, ten rattle noise signals of the highest relative approaches are identified within 3.5 s in the full vehicle test. The results show that the occurrence time obtained by the rattle noise relative approaches is entirely coincided with that of the ten rattle noise signals which is recorded in the raw noise signals playback. The results of the rattle noise identification are consistent with that of the subjective perception. Thus the gear rattle noise is identified accurately. The interference of the noise signals of the engine, the chassis dynamometer, the environment and the loaded gears is effectively removed by the noise relative approaches to avoid false diagnosis. Gear rattle vibration signals on transmission housing obtained in the full vehicle test are similar to those of the rattle noise. Therefore, the occurrence time, frequency and level of the rattle vibration also can be obtained by the relative approaches. Results show that bigger relative approach represents higher gear rattle noise and vibration level. The gear rattle vibration signals of the transmission housing always coincide with all the rattle noise signals of the driver’s right ear which delay the rattle vibration signals for 0.01∼0.04 s. Thus the transmission housing is the major transfer pathway of the gear rattle noise. The frequency range of the gear rattle noise is within that of the rattle vibration because of the noise transfer function from the transmission housing to the driver’s right ear. The gear rattle vibration characteristics of each surface and direction are different. Therefore, the rattle anisotropy can be considered when rattle mechanism is investigated. The rattle vibration of the upper, front and left surfaces on the transmission housing is higher than other surfaces. Those three surfaces are the major improvement targets for optimization of the rattle performance."
A Multiproduct Multimaterial Solution for Lightweight Vehicle Doors,"Light weighting of vehicle doors is a challenge faced by all vehicle manufacturers - whether passenger cars and vans or large commercial vehicles like trucks and buses. This need is driven not only by the desire to improve the vehicle's fuel economy, but also by the implication of the doors on the buyer's perception of the vehicle's quality. The best solutions to these needs emerge from an unbiased consideration of different materials and product forms in the design and development of lightweight doors. To demonstrate this notion, a truck door was designed that has the potential of providing both improved fit as well as enhanced structural performance. The concept also simplifies the manufacturing process thereby minimizing system cost while offering approximately 7% additional weight saving compared the door already made from light weight materials (aluminum). This paper describes the design concept for lightweight vehicle doors using aluminum in its various product forms as well as other materials."
Development of Power Sliding Door (PSD) System with Push-Pull Cable Driving Method,"We have developed a power sliding door (PSD) system driven by a push-pull cable. The door closure and slide are operated by different actuators to limit the force required for a compact, light-weight drive unit. This paper introduces the concept of the PSD system using a push-pull cable drive. Two new technologies to achieve the PSD system are also described. One is the door position control for increasing the push-pull cable reliability. The other is a compact position sensor to accurately detect the sliding door's position."
Door Open Overload: Margin and Flushness Approach,"Since doors are repeatedly used by vehicle owner, they have a great influence on his or her perception of vehicle quality. The door open overload is an abusive load requirement for customer usage. The doors must withstand loads which force the door open against its stop, leading to concern over the effects of permanent set to the functioning of the door system and the margins/ flushness. Traditionally, the CAE is utilized to objectively evaluate the deflections and permanent set at the door latch to evaluate door open overload requirement. In this study, the FEA methodology has been applied to expand the scope beyond traditional method to simulate door open overload condition. The change in the margin and flushness due to the permanent set are evaluated using nonlinear analysis (ABAQUS). The results show that the method helps designers to ensure the door meets the margin/flushness criteria for door open overload condition during early stage of the door design process."
Experimental Assessment Of Door Window Glass Smooth Operation And Tracking,"Since the door glass windows are used regularly, they have a great influence on the vehicle owner's perception of vehicle quality. Today's customers demand that moveable door window glass operates smoothly. Experimental methods have been developed to evaluate window glass smoothness and positional stability. This paper presents experimental results that quantify the chattering and positional stability of the window glass. For window glass smooth operation and tracking, the measurements were taken on glass chatter, glass velocity, motor current, motor voltage, and glass stall force. The change in glass position was measured on the vehicle during several stages of four poster durability testing to evaluate window glass positional stability during road induced vibrations. Using these experimental methods, the designers should be able to evaluate several window glass functional requirements and achieve cost/time savings."
Sled System Requirements for the Analysis of Side Impact Thoracic Injury Criteria and Occupant Protection,"This paper discusses struck-side occupant thoracic response to side-impact loading and the requirements of a sled system capable of reproducing the relevant motions of a laterally impacted vehicle. A simplified viscoelastic representation of a thorax is used to evaluate the effect of the door velocity-time profile on injury criteria and on the internal stress state of the thorax. Simulations using a prescribed door velocity-time profile (punch impact) are contrasted against simulations using a constant-velocity impact (Heidelberg-type impact). It is found that the stress distribution and magnitude within the thorax, in addition to the maximum thorax compression and viscous response, depend not only on the door-occupant closing velocity, but also on the shape of the door velocity-time profile throughout the time of contact with the occupant. A sled system capable of properly reproducing side-impact door and seat motion is described."
Analysis and Design of Slow Build Studies During Sheet Metal Assembly Validations,"Several manufacturers are adopting six sigma programs in efforts to reduce stamping variation. This requires the crucial step of establishing dimensional relationships for the stamping dimensional outputs that become key process inputs to the assembly process. This paper describes a methodology used to determine the root cause of dimensional changes in a front door assembly. Among the key findings in this study are the importance of understanding the effects of the datum-locating scheme and the significant influence of assembly processing variables, rather than stamping variability, on the final door assembly dimensional quality."
Parametric study of side impact thoracic injury criteria using the MADYMO human body model,"This paper presents a computational study of the effects of three parameters on the resulting thoracic injury criteria in side impacts. The parameters evaluated are a) door velocity-time (V-t) profile, b) door interior padding modulus, and c) initial door-to-occupant offset. Regardless of pad modulus, initial offset, or the criterion used to assess injury, higher peak door velocity is shown to correspond with more severe injury. Injury outcome is not, however, found to be sensitive to the door velocity at the time of first occupant contact. A larger initial offset generally is found to result in lower injury, even when the larger offset results in a higher door velocity at occupant contact, because the increased offset results in contact later in the door V-t profile - closer to the point at which the door velocity begins to decrease. Cases of contradictory injury criteria trends are identified, particularly in response to changes in the pad modulus. Maximum chest deflection and maximum viscous criterion gradually decrease as the padding modulus increases. TTI, however, increases with some increases in pad modulus. Complex interactions among the three parameters are observed, and their interpretation is shown to depend on the specific injury criterion analyzed."
Evaluation of Variation in the Excursion Measured in the FMVSS 226 Ejection Mitigation Test Resulting from Test Vehicle Setup,"Federal Motor Vehicle Safety Standard 226 outlines a component test methodology that consists of a linear impact test that uses a featureless head-form with a mass of 18 kg to impact a vehicle's side windows' daylight openings at various positions. The test measures the excursion of the head-form beyond the plane of the window glazing. The intention is to evaluate the ability of a vehicle's ejection mitigation system, such as the curtain airbag or other vehicle features, to manage the impactor energy and limit excursion. However, there are several factors which may cause variation in the amount of excursion measured in the test. These factors include how the vehicle is restrained for the test, the friction of the linear impactor shaft and the lateral deflection of the impactor shaft among others. This paper will present background information from a previous study on variability involving the impactor shaft as well as a study which identifies the effects of vehicle restraint on the excursion measured in the Federal Motor Vehicle Safety Standard (FMVSS) 226 test."
Structural-Acoustic Analysis of Vehicle Body Panel Participation to Interior Acoustic Boom Noise,"A structural-acoustic finite element model of an automotive vehicle is developed and applied to evaluate the effect of structural and acoustic modifications to reduce low-frequency ‘boom’ noise in the passenger compartment. The structural-acoustic model is developed from a trimmed body structural model that is coupled with an acoustic model of the passenger compartment and trunk cavities. The interior noise response is computed for shaker excitation loads at the powertrain mount attachment locations on the body. The body panel and modal participation diagrams at the peak response frequencies are evaluated. A polar diagram identifies the dominant body panel contributions to the ‘boom’ noise. A modal participation diagram determines the body modes that contribute to the ‘boom’ noise. Finally, structural and acoustic modifications are evaluated to determine their effect on reducing the ‘boom’ noise and on the overall lower-frequency sound pressure level response."
NVH Improvement for Three Wheeler,"In India, demand for three wheelers with low noise is increasing among the customers thereby the noise reduction of three wheelers is necessary. In order to overcome the demand in the market, manufactures are giving more importance to noise levels at passenger ear level and driver ear level. In test vehicle it was found that engine is the main noise source, biggest challenge was to reduce noise transfer from engine compartment to passenger and driver ear. In three wheelers it is more difficult as there is no close cabin. This paper main objective is to reduce noise levels at driver and passenger ear level. The objective and subjective evaluations of both vehicles were carried out to identify the levels at driver ear level and passenger ear level. First task was to find out noise sources in engine. Most dominating noise source was tappet and flywheel area. Modifications were done on tappet cover and flywheel cover to reduce noise levels. Different techniques were used in this project like partial enclosure of engine, modifications in vehicle engine compartment. The result shows reduction in sound levels at passenger and driver ear level in modified vehicle comparing with old vehicle."
Use of Statistical Energy Analysis in Vehicle NVH Design Cycle,"Statistical Energy Analysis (SEA) is used to predict high-frequency acoustic and vibration response in vehicle NVH design. Early in the design cycle prototype hardware is not yet available for testing and the geometry is still too poorly defined and changing too quickly for Finite Element Analysis or Boundary Element Analysis to be an effective NVH analysis tool. For most of the concept phase and early design phase, SEA uniquely offers the ability to virtually predict the main noise transfer paths and to support target setting for component and full vehicle NVH design. At later stages of the design process, SEA combines with NVH testing to provide more accurate predictions and to provide guidance for more efficient testing. This paper describes the established uses of SEA in the vehicle industry and presents an overview of the NVH design cycle and how SEA is used to support NVH development at different stages. The synergy between SEA analysis and full-vehicle and component-level NVH testing is discussed. The types of testing that most effectively validate the SEA models and the methodology for validating the models are presented. Case studies for several vehicle NVH applications are presented with examples of the use of SEA prediction and validation measurements. Overall advantages, limitations, and use of SEA to increase the efficiency of the NVH development test effort are summarized."
Acoustical Performance of Baffle Design Options for Water Management,"Expandable cavity sealers have become a critical component of the overall acoustic package that contributes to the documented noise reduction in passenger car applications over the course of the last twenty years. They encompass a variety of technologies, some of which are delivered into the supply chain as bulk materials and others which are highly engineered parts and assemblies. As the market for smaller and more fuel efficient vehicles continues to expand, design architectures of the base vehicle platforms are evolving to include body designs with smaller spaces between adjacent layers of sheet metal. As this space, or cavity, between the adjacent layers of sheet metal is shrinking, the complexity of components that must be integrated into the space between these layers of steel is increasing. Complex arrays of airbags, corresponding wire harnesses, and water management tools are now standard requirements in the design process. To manage the complexity of these lightweight and fuel efficient vehicle architectures, new engineering design solutions are required to meet stringent acoustic requirements. The supply base of acoustic products to the automotive OEMs has also matured over this time period, creating a very competitive environment, both regionally and globally. Design solutions that go beyond the basic functionality of a cavity filler are becoming more common. This paper will evaluate a recent design challenge presented by an OEM to improve visibility for the driver. Here, the hardware to direct water drainage is moved from outside the windshield pillar cavity body metal to inside the cavity metal. A new cavity filler solution is conceptualized to manage this unique packaging and acoustic performance need. Although it's in its infancy, the solution, along with other means of water management, are measured for Insertion Loss and compared. This initial study supports the promise for acoustic performance of a solution that does not exist in the market today."
ULSAC - Lightweight Steel Automotive Closures,"Following the success of the UltraLight Steel Auto Body (ULSAB) in 1997, the UltraLight Steel Auto Closure (ULSAC) Consortium representing steel producers from all over the world was founded. Porsche Engineering Services, Inc. (PES) was commissioned to conduct a concept study for the development of UltraLight Steel Auto Closure concept designs for all types of automotive closures that were structurally sound at affordable cost. The Validation Phase began in November 1998. In spring 2000, the ULSAC DH Door Structures featuring stamped Door Outer Panels were built and tested for structural performance, dent resistance and oil canning. The tested doors show state-of-the-art structural performance compared to today's frameless door structures, and the mass reduction ranges from 22 to 42% compared to the normalized mass of benchmarked doors. In the Validation Phase, a cost model was developed and the cost to produce the ULSAC frameless door structure was calculated. The results of this cost estimation show that the ULSAC door can be manufactured in high-volume production with no cost penalty."
Dimensional Management - Setting Static and Dynamic Dimensional Goals Concurrently,"The main element of dimensional management is specification cascading where customer requirements are translated into dimensional targets. It also includes GD&T, datum strategy, and tolerance optimization. These elements can only be effective if all of the work is done concurrently among various disciplines of an organization that have a stake in the fit, finish, and performance of the final product. When setting static dimensional goals during product development, vehicle performance targets and dynamic goals have to be defined simultaneously. One example is of the final door appearance for gaps and flushness on an automotive body from static standpoint. The wind-noise and door flutter are examples of dynamic performance goals. It becomes very costly to fix static fit and finish issues caused by the dynamic state of the vehicle late into the product development cycle or at the customer locations."
Developing a Sonar-Assisted Device for the Blind,"At Wake Forest University, Winston-Salem, NC, a biology professor researching echolocation in bats teamed up with an associate professor of computer science and an interdisciplinary team of students to develop a device that can help the visually impaired navigate better. Their research focused on developing a device that could be worn like a watch by a visually-impaired person as a supplement to other aids like a cane or guide dog."
Automotive Engineering: May 2018,"Testing for cold-climate comfort AE goes way north to the Arctic Circle for an inside look at Hyundai's winter testing of the new Nexo FCV and Kona EV and their unique and critical HVAC systems. Innovation more than skin deep A new wave of engineered plastics are delivering structural, mass-reducing, and aesthetic benefits for new vehicle applications. A secret weapon for roof-crush testing Before you crush that bus or racecar chassis, find out how engineers at CAPE are optimizing test-rig performance. Editorial: Tesla's Model 3 is two very different cars SAE Standards News A hive of activity Supplier Eye Why aren't there more unibody pickups? The Navigator We can't trust humans to supervise machines Acura and ArcelorMittal debut world-first hot-stamped door ring system on 2019 RDX Powertrain analyst: Light-vehicle fleet needs big gains to meet tightening emissions regs Toyota unveils more gasoline ICEs with 40% efficiency IAV using 3D-printed pistons for engine testing 2018 Kona debuts Hyundai's new B-SUV platform Nissan variable-compression engine gets first shot at volume with new 2019 Altima Q&A Honeywell's Geoff Duff talks turbos"
"Windshield Defrosting Systems Test Procedure and Performance Requirements—Trucks, Buses, and Multipurpose Vehicles","This SAE Recommended Practice establishes uniform test procedures and performance requirements for the defrosting system of enclosed cab trucks, buses, and multipurpose vehicles. It is limited to a test that can be conducted on uniform test equipment in commercially available laboratory facilities. Current engineering practice prescribes that for laboratory evaluation of defroster systems, an ice coating of known thickness be applied to the windshield and left- and right-hand side windows to provide more uniform and repeatable test results, even though under actual conditions such a coating would necessarily be scraped off before driving. The test condition, therefore, represents a more severe condition than the actual condition, where the defroster system must merely be capable of maintaining a cleared viewing area. Because of the special nature of the operation of most of these vehicles (where vehicles are generally kept in a garage or warmed up before driving) and since defrosting under steady-state over-the-road operations is the main concern, test conditions have been adopted which assume that the engine is warm before the vehicle is driven. There are two options for producing hot coolant in this recommended practice. Testing using these two approaches on the same vehicle will not necessarily provide identical results. Many vehicle models are offered with optional engines, and each engine has varying coolant temperatures and flow rates. If the test is being conducted to compare the performance of one defroster design to another defroster design, then the external coolant source approach (Test A) will yield the most comparable results. If the test is being conducted to validate the defroster installation on a specific vehicle model with a specific engine, then using the engine to heat the coolant (Test B) will be more appropriate. This document will be reviewed and revised as technological progress in vehicle defroster test procedure requires."
Road Noise Identification and Reduction Measures,"In a scenario where cost and weight targets are becoming critical, we tend to produce lighter and more powerful vehicles. In this context, NVH becomes one of crucial parameters in overall performance delivery. Other than power train, road induced noise also becomes an important parameter within vehicle development. Predecessor vehicle is body over frame structure and here a monocoque vehicle is considered for study. Different techniques like transfer path analysis, vibro-acoustic modal analysis, operational deflection shapes are used to identify the major force paths, radiating panels and their sensitivity to noise at operator ear location. Simulation model of body is built with good correlation and input forces are given at different attachment points to predict the noise levels. This combined approach helped us in reducing the overall noise level at certain constant speed by 4 dB(A) and also with great ease. All recommendations from this exercise are implemented"
Vehicle Airborne Noise Analysis Using the Energy Finite Element Method,"The Energy Finite Element Analysis (EFEA) has been developed for computing the structural vibration and the interior noise level of complex structural-acoustic systems by solving numerically governing differential equations with energy densities as primary variables. In this paper a complete simulation process for evaluating airborne noise in an automotive vehicle is presented and validated through extensive comparison to test data. The theoretical elements associated with the important paths of the noise transfer from the exterior of the vehicle to the interior acoustic space are discussed. The steps required for developing an EFEA model for a vehicle are presented. The model is developed based on the physical construction of the vehicle system and no test measurements are utilized for adjusting the numerical model. An acoustic noise source is placed at each one of four vehicle locations (engine compartment, front left tire patch, rear left tire patch, and exhaust) where typical exterior noise sources are present in an operating vehicle. The exterior acoustic field is evaluated numerically by the Energy Boundary Element Analysis (EBEA). The acoustic loading from each source is applied on all of the outer parts of the vehicle EFEA model and the interior noise level is computed in the frequency range of 200Hz - 8,000Hz. Predictions for the interior noise level (expressed in a noise reduction format) are compared with test results for all four excitations. The ability of the EFEA method to conduct a panel contribution analysis is used for identifying the panels which contribute the most to the power flow from the structure to the interior acoustic space. Such information is useful in making design decisions when implementing noise mitigation strategies."
A Software Library for Active Control of Automotive Engine Noise,"A general-purpose software solution for active control of engine noise within vehicle cabins is described. The feed-forward system, based on FxLMS algorithm, reduces engine orders below 150 Hz by emitting independent control signals from one or more loudspeakers in the cabin, and uses one or more microphones inside the cabin to monitor noise levels and adapt control filters. The software solution is a C/C++ callable library with floating-point and fixed-point versions, which would normally be ported to a DSP or application processor situated in the head-unit or power amplifier of the audio/infotainment system. We provide a comparative analysis of our integrated software library versus a mass-production solution in a Honda Odyssey, which shows that the software library, with a very reasonable computational complexity, provides a low-cost alternative to a dedicated ANC system whilst achieving comparable performance and robustness."
Correlation of Dominant Noise Transfer Paths in Statistical Energy Analysis Vehicle Model from Test as Basis for Variant Vehicle Development,"For purposes of reducing development time, cost and risk, the majority of new vehicles are derived strongly or at least generally from a surrogate vehicle, often of the same general size or body style. Previous test data and lessons learned can be applied as a starting point for design of the new vehicle, especially at early phases of the design before definite design decisions have been finalized and before prototype of production test hardware is available. This is true as well of vehicle NVH development where most new vehicles being developed are variants of existing vehicles for which the main noise transfer paths from sources of interest are already understood via test results and existing targets. The NVH targets for new vehicles are defined via benchmarking, market considerations, and other higher-level decisions. The objective is then to bridge the gap between test data from surrogate vehicles to direct support of the NVH development of new vehicle programs. Because of its strength in providing analysis predictions of the effect of design changes on vehicle NVH at higher frequencies, Statistical Energy Analysis (SEA) is an established tool for using available test data to correlate an SEA model that can be adapted for early design phase NVH development of new vehicles. The effect of changes to materials, gage thickness, sound package, source levels, or geometry changes on the interior noise levels can be predicted by SEA with good accuracy to support design decisions that must be made early in the program. This paper illustrates with a concrete example an idealized implementation of this process. The main test plan design considerations for a baseline surrogate vehicle are discussed. Some key test results and their uses are presented. The updating and correlation of an SEA model representing the baseline vehicle are shown. The objective methods for determining the effectiveness of the correlation are given using this vehicle as an example. Finally, the use of a correlated SEA model to effectively support the NVH development of several variant vehicle programs at an early phase of the design process is presented along with suggestions for the best use of this design tool, its advantages and limitations, and the most effective roles it can serve to support the overall vehicle design cycle."
Ventilation Improvement in a Non-AC Bus,"Ventilation is a crucial factor affecting passenger comfort in any vehicle. In a non-air-conditioned bus, ventilation caters to the dual requirement of fresh breathing air as well as providing a cooling sensation by enhanced evaporation of sweat. The higher the velocity of air around the passengers, the greater the cooling effect experienced by them. The ventilation mechanism of a non-air-conditioned bus is primarily the air flow through the windows due to relative motion between the bus and the air around it. This paper describes studies carried out to identify the right combination of open windows which would provide optimum air flow at the passenger head level plane in a bus. A bus model with 12 windows, 6 on each side is used for the study and air velocity at certain points in the head level plane, arising out of different combination of window openings is evaluated using CFD. The minimum value of velocity observed among the points, which is indicative of the minimum level of comfort provided by the combination, is compared for different combinations of openings and the optimum identified. Since a comparison of all possible combinations would involve evaluating 312 CFD runs, Design of Experiments (DOE) is used to obtain the optimum using a reduced number of analyses. Through this study it is attempted to place windows only at few strategic locations that would contribute to optimum air flow at all points within the bus by eliminating the non contributing windows without reduction in passenger comfort, thereby changing bus design philosophies and providing greater freedom in bus design. The optimum configuration of windows was found to provide ∼17% reduction in window area."
Active Noise Control for the 4.0 TFSI with Cylinder on Demand Technology in Audi's S-Series,"To significantly increase fuel efficiency while keeping power and performance of its signature S models, AUDI developed a new 4.0 TFSI engine with Cylinder on Demand technology and introduced it with its new S6, S7 and S8 models. To manage upcoming NVH issues due to this new technology and keep the intended sporty V8 note of the engine under all operating conditions, a broad range of new and advanced technologies was introduced with these vehicles. This paper focusses on the Active Noise Control system and its development. It describes the ANC system from a control theory perspective in addition to the acoustical perspective. Special features of the system include the availability of multiple tunings (4/8 cylinder mode) to support the specific overall sound character and the fast switching process as switching between different cylinder configurations might be as fast as 300 ms. In addition, the system also includes specific features that allow an advanced audio system diagnosis. Last but not least, some aspects of the development process will be highlighted."
Further Development of Velocity-based Airborne TPA: Scan & Paint TPA as a Fast Tool for Sound Source Ranking,"The interior noise of a car is a general quality index for many OEM manufacturers. A reliable method for sound source ranking is often required in order to improve the acoustic performance. The final goal is to reduce the noise at some positions inside the car with the minimum impact on costs and weight. Although different methodologies for sound source localization (like beamforming or p-p sound intensity) are available on the market, those pressure-based measurement methods are not very suitable for such a complex environment. Apart from scientific considerations any methodology should be also “friendly” in term of cost, time and background knowledge required for post-processing. In this paper a novel approach for sound source localization is studied based on the direct measurement of the acoustic particle velocity distribution close to the surface. An airborne transfer path analysis is then performed to rank the sound pressure contribution from each sound source. The method called “Scan & Paint TPA” makes use of only one probe that is swept along the surface. The reciprocal transfer functions are measured by a second sweep with the same probe and a monopole sound source in the driving position. A new methodology for applying “Scan & Paint TPA” in a complex acoustic environment is given along with an experimental validation in a car interior."
Functional Vehicle Design for Urban Mobility,"When approaching new mobility solutions such as car-sharing, it soon becomes apparent that it may be necessary to develop specific vehicles for this application. In this paper, Applus IDIADA explains its experience in the development of the iShare, an electric vehicle conceived as a demonstrator of our complete vehicle development capabilities following the principle of “development led by functionalities”, with the consideration that it would be used in open car-sharing fleets running according to the MIT's (Massachusetts Institute of Technology) “mobility-on-demand” concept. This paper explains the process followed in order to reach the definition of the different parts, systems and components that are the result of the consideration of the Technical Functionalities, such as Active Safely, Passive Safely, Driveability, NVH, Fleet Management, Maintenance and Comfort, that in their turn result from the basic vehicle specifications defined from the analysis of the key functionalities of this vehicle that are suitability for the car-sharing business model and the mobility requirements of the potential customers. In particular, the paper includes details about the vehicle layout analysis and why a 4-wheel and 2-parallel seats configuration was chosen instead of 2- o 3-wheel or 2-tandem seats configuration, the powertrain, steering, suspension, braking, Passive Safety and energy efficiency concepts explored, the process allowing a customer to book and have access to a given vehicle without a physical key and finally the systems to allow the car-sharing operator to keep the cars in good conditions by replacing interior and exterior trims easily and inexpensively and recycling the materials to make new trims out of it."
Seat Squeak Measurement and Diagnosis,"BSR (Buzz, Squeak and Rattle) is one of the oldest concerns in automobiles which directly reflect the build, assembly and manufacturing quality of a vehicle. In a cabin all the areas where there is relative motion between two components, such as trims, instrument panel and seats, are prone to squeak. This paper explains the study of seat squeak measurement and diagnosis which is a major concern for one of the products which is already in the market. Since squeak is a friction induced non stationary phenomenon, lot of effort was required to generate squeak in both component as well as vehicle level. At component level, electrodynamic shaker was extensively used for generation of squeak signals. In Vehicle level, driving through different road patterns, pave track and forced excitation on four posters are performed for generation of squeak signals. In this paper usage of wavelet and Zwikker loudness are explained for the diagnosis of seat squeak to identify the problematic frequencies. Results in both pave track condition and in four poster excitation method are presented."
Multidisciplinary Design Optimization of a Hatchback Structure,"Lightweight automobile has an important role in saving the energy, improving the fuel economy and reducing the exhaust emission. However, reducing the mass of the automobile need to meet the structural and NVH (Noise, Vibration and Harshness) performance requirements. With the rapid development of Computer Aided Engineering (CAE) technology, more and more people tend to research the complex engineering application problem by computer simulation. An important challenge in today's simulation is the Multidisciplinary Design Optimization (MDO) of an automobile, including mass, stiffness and modal etc. This paper presents a MDO study in a minicar hatchback. The aim of the study is to minimize the mass of the hatchback while meeting the following requirements: (1) Structural performance. the bending stiffness is higher than the original data and the sagging residual deformation is less than the original data. (2) NVH performance. the lowest natural vibrational frequency is higher than the original data. The sample points are obtained by the Design of Experiment (DOE) with optimal Latin Hypercube and the approximation models of mass, modal, bending stiffness, sagging are established with polynomial response surface method. The thicknesses of the major components in the hatchback are selected as design variables. The approximation models are optimized by sequential quadratic programming method. A good agreement between the predictive values of the approximation and the results of finite element simulation with the error less than 5% is demonstrated. The predictive values of the approximation meet the engineering requirement. Consequently, the optimized results have higher accuracy. In the process of the optimization design, the weight of the hatchback reduced by 6.5% and the new hatchback meets all the prescribed requirements about structural and NVH performance."
Effect of Glazing Thermal Conductivity on Cabin Soak Temperature,"Previous papers by the present authors described use of computational fluid dynamics (CFD) to quantify the effect of glazing thermal conductivity on steady-state heating, ventilation and air-conditioning (HVAC) load under wide-ranging climate and state of motion scenarios, and to estimate the significance of this effect for electric battery performance. The CFD simulations yielded the total heat transfer between the ambient and the cabin of a model car, including radiative and convective heat transfer. The five-fold lower inherent thermal conductivity of polycarbonate relative to glass was found to reduce steady-state HVAC load by several percent in all scenarios, leading to reduced greenhouse gas emission or increased electric range, according to the type of vehicle. This paper complements the previous study by quantifying through simulation the effect of glazing thermal conductivity on cabin soak temperature, the latter reflecting a balance between radiative and convective heat transfer in a closed, unventilated, parked car with HVAC off, in a hot, sunny environment. Soak temperature has been a focus in the regulatory arena as an initial condition in proposed tests of air-conditioning contribution to tailpipe emissions. Two glazing configurations are simulated: a baseline configuration with glass at all locations, and a reduced thermal conductivity configuration with polycarbonate glazing substituted at the backlite and rooflite. A difference in soak temperature of less than 1°C is found for the two glazing configurations under the conditions of relatively high solar radiation and ambient temperature in Phoenix, Arizona at mid-day in June. This difference is small compared to both the soak temperature relative to the ambient and the variation in soak temperature found for a range of optical and heat transfer parameters for non-glazing elements of the cabin. The insignificance of glazing thermal conductivity for soak temperature is reconciled with its significance for steady state HVAC load in terms of air movement at the inside and outside glazing surfaces."
A Development of Smart Ventilation System,"There are some problems “windows fog up a lot” for ventilation system. We have Test Development Procedure to prevent the fog problems. But, Many fog problems occurred in the cars that we made. So in this paper, new ventilation system is needed and developed. The Smart Ventilation System automatically controls indoor air quality even though the blower motor is off. There are two sensors that is used for AutoDefogSensor system and CO2 CONTROL system.. The sensor is on when blower motor and heater control is off. We use these signals and make new ventilation logics. We evaluate this system in chamber & '13 winter test in USA."
Development of an Acoustic Material Database for Vehicle Interior Trims,"Characterizing the acoustic properties of sound-absorbing materials is costly and time consuming. The acoustic material database helps the automotive designers design their interior trims in accordance with target level for interior noise. In this paper, a two-microphone impedance tube was used to measure the normal sound absorption coefficient. The main parameters that are used in the theoretical model for interior noise level assessment are investigated. These parameters include thickness, airflow resistivity, porosity, tortuosity, viscous and thermal characteristics length. The measured results have been validated by the theoretical models. The validation of normal sound absorption coefficient was found to be in agreement with its corresponding measurement data. Finally, the sensitivity of the sound absorption coefficient which is related to the physical properties mentioned above is further analyzed."
Optimal Design of Vehicle Dash and Floor Sound Package Based on Statistical Energy Analysis,"An increasing demand for vehicle noise control has been proposed and at the same time, vehicle weight and fuel economy have become critical for the automotive industry. The methodology of statistical energy analysis (SEA) is used to balance both light weight and high noise insulation performance. In this paper, the vehicle dash and floor sound package systems, which are two of the major paths for vehicle interior noise, are studied and optimized by CAE and testing technology. Two types of sound packages which are the conventional insulation system and the lightweight one are chosen for the vehicle dash and floor system. The vehicle dash and floor systems are modeled by SEA and the transmission loss (TL) of the dash and floor system is analyzed, respectively. Several influence factors of the TL are also analyzed, such as sound package coverage, the leaks, etc. The results of the TL analysis show that under certain sound package coverage or leaks, the TL of the dash and floor system with the conventional sound package is a little larger than the TL with the lightweight one. However, the lightweight sound package system has better absorption property and the advantage of weight reduction. Meanwhile, the full vehicle SEA model is built up and the noise transfer path is analyzed. By using the full vehicle noise reduction tests, the full vehicle SEA model and the main noise transfer paths are validated. Then, the vehicle exterior sound pressure levels (SPL) are tested under several load cases inside a semi-anechoic chamber. By applying the vehicle exterior SPLs to the full vehicle SEA model, the correlations are performed between the simulation and tests. Finally, the sound package systems of the dash and floor are analyzed and optimized by the full vehicle CAE and testing analysis."
"Scientists Build Thinnest-Possible LEDs To Be Stronger, More Energy Efficient","Most modern electronics, from flat-screen TVs and smartphones to wearable technologies and computer monitors, use tiny light-emitting diodes, or LEDs. These LEDs are based on semiconductors that emit light with the movement of electrons. As devices get smaller and faster, there is more demand for semiconductors that are tinier, stronger and more energy efficient."
SUPPLIER EYE,"Are you innovating for NVH? I'll never forget the experience, as a kid, of lifting the massive steel hood of my father's 1971 Dodge Monaco and seeing nothing but V8 engine and a few rubber hoses. The vast compartment was so uncluttered, I could look straight down and see the pavement. By comparison, the view under today's vehicle hoods reveals a dense landscape of technologies aimed at acoustic control: covers, shields and insulators designed to keep injector clatter, induction honk and even pulley whirl muffled. Supplier innovations are central to winning the ongoing war with NVH-noise, vibration and harshness. The battle started decades ago and will certainly increase in the future. This is an engineering realm with numerous tradeoffs involving total piece cost, capital cost, stranded fixed capital, tooling complexity/count, system optimization, flexibility, intellectual property and even downstream warranty. But because NVH (more accurately, the lack of it) has direct impact on the end customer, it has become a commitment rather than an option across vehicle segments."
Lincoln unveils Big-SUV future with Navigator concept,"Intent on staying on its message of reinvigorating its brand under the banner of “quiet luxury,” Ford's premium-vehicle unit, Lincoln, used the 2016 New York auto show to reveal what almost certainly will be remembered as one of the most audacious concept cars ever, the Lincoln Navigator Concept. Two stupendously-sized gullwing doors lift to allow full access to the SUV's first and second seating rows, with 30-position adjustable seats “floating” on pedestal attachments that eliminate traditional seat tracks, full-length “concertina” steps are power-deployed to create a waterfall of steps for entry and exit, and a “wardrobe management system” in the cargo area looks like something Tony Stark dreamed up to secure his Iron Man gear."
Autonomous Robotic Manipulation (ARM),"Autonomous robotic manipulators have the potential to increase manufacturing efficiency, provide in-home care, and reduce the risk to humans in hazardous situations. The current challenge in autonomous robotic manipulation is to approach the capabilities of dedicated, one-off manipulators in known environments with versatile, inexpensive, and ubiquitous manipulator systems that can operate in a range of environments with only high-level human input."
Dual-Compartment Inflatable Suitlock,"There is a need for an improvement over current NASA Extravehicular Activity (EVA) technology. The technology must allow the capacity for quicker, more efficient egress/ingress, allow for “shirtsleeve” suit maintenance, be compact in transport, and be applicable to environments ranging from planetary surface (partial-g) to orbital or deep space zero-g environments. The technology must also be resistant to dust and other foreign contaminants that may be present on or around a planetary surface. The technology should be portable, and be capable of docking with a variety of habitats, ports, stations, vehicles, and other pressurized modules."
The Thermal Hogan — A Means of Surviving the Lunar Night,"A document describes the Thermal Hogan, a new shelter concept that would be used on the Moon to moderate the extreme nighttime temperatures, allowing survival of equipment with minimal heater power. It is lightweight, has few mechanical parts, and would be relatively easy to deploy on the Moon."
Dual-Compartment Inflatable Suitlock,"A paper discusses a dual-compartment inflatable suitlock (DCIS) for Extra-vehicular Activity (EVA) that will allow for dust control, suit maintenance, and efficient EVA egress/ingress. The expandable (inflatable technologies) aspect of the design will allow the unit to stow in a compact package for transport."
"Wearable, Artificially Intelligent, Bionic Device","eLEGS is a wearable, artificially intelligent, bionic device that enables people with paralysis to stand up and walk again. The exoskeleton is battery-powered and rechargeable, fitting comfortably and securely over clothing."
Microcontroller Based Low Cost Illumination Control and Warning System,"This paper demonstrates the design, development and validation techniques for the vehicle illumination control system typically used for emerging market applications with limited program variable costs and more features needs to be packed in a controller module. The system, powered by an 8-bit RISC Harvard microcontroller, controls the in-car illumination by triggered time delay and a PWM controlled theatre-dimming effect for predefined duration. It further alarms the driver and co-driver if the exterior lamps are left ON and doors opened. The module is packed on a 30 mm square base with height 50 mm and mounted in the CJB. The paper concludes with a generic methodology for designing such robust systems for the cost and quality conscious automotive society."
"The Design of an Acoustics Laboratory for Off-Highway, Heavy Truck, and Recreational Vehicles","The new Blachford Acoustics Laboratory was designed specifically for acoustical testing of large vehicles, such as off-highway machines, recreational vehicles, and heavy trucks. While there are many automotive and architectural test laboratories for which a new laboratory can be based, there are very few acoustics laboratories capable of testing these larger vehicles. However, by drawing on the experience with the previous Blachford Laboratory, several off-highway manufacturers' test facilities, and the newer automotive manufacturer and supplier laboratories, a functional and cost effective design was developed. This design features indoor and outdoor test areas, including a large hemi-anechoic chamber equipped with a chassis dynamometer, a reverberation room with several transmission loss openings, work rooms, office areas, and a 10 meter radius outdoor drive-by pad. Special design considerations included door size, component test opening dimensions, dynamometer axle and floor loading capabilities, cooling and exhaust extraction flow rates, and special electrical connections. In addition, the site chosen for the laboratory also provided many challenges."
"Wavelet-Based Visualization, Separation, and Synthesis Tools for Sound Quality of Impulsive Noises","Recent applied mathematics research on the properties of the invertible shift-invariant discrete wavelet transform has produced new ways to visualize, separate, and synthesize impulsive sounds, such as thuds, slaps, taps, knocks, and rattles. These new methods can be used to examine the joint time-frequency characteristics of a sound, to select individual components based on their time-frequency localization, to quantify the components, and to synthesize new sounds from the selected components. The new tools will be presented in a non-mathematical way illustrated by two real-life sound quality problems, extracting the impulsive components of a windshield wiper sound, and analyzing a door closing-induced rattle."
Interior Fittings – A Global View,"In today's global economy, the automotive design engineer's responsibilities are made more complex by the differences between regulatory requirements of the various global markets. This paper compares instrument panel head impact requirements of FMVSS 201 with its European counterparts, ECE 21, and EEC/74/60, Interior Fittings. It describes the similarities and differences between these regulations and explains the unique requirements for each market. It then compares processes for development and validation testing in both markets. It also covers related topics like self-certification, witness testing, radii, projections, and interior compartment doors. The cockpit design engineer will gain an understanding of the factors involved in ensuring that their design fully meets the requirements of the subject regulations."
Use of Acoustical Holography for Efficient 3D Measurement in Car Interiors,"A continuously growing demand comes from the automotive industry for optimization of materials and sound insulating product packaging inside the car, so as to propose the best acoustic performance at reduced costs. A new acoustical holography system provides part of the solution to meet such a demand. The capability of measuring the acoustic field inside a vehicle with high spatial resolution makes it an advanced tool for performing extensive studies of the acoustic transparency of car openings and interior components in various environmental conditions (acoustic chamber, on road, in wind tunnel). The method allows for: Detailed localization of noise sources or leaks, Knowledge of the acoustic energy distribution on elementary surfaces (such as doors, windscreen, roof, sealing components, …), Reconstruction of the energy radiated by elementary surfaces in order to predict the acoustic pressure at driver's and passengers' ears, Introduction of local modifications on subsystems and components in order to predict their effect on the acoustic field. In conjunction with some numerical prediction methods, this technique will allow to apply integrated acoustic engineering design methods for a complete understanding and control of the large variety of components and systems involved in the car performance."
"Automotive Body Structure Enhancement for Buzz, Squeak and Rattle","Today, the interior noise perceived by the occupants is becoming an important factor driving the design standards for the design of most of the interior assemblies in an automotive vehicle. Buzz, Squeak and Rattle (BSR) is a major contributor towards the perceived noise of annoyance to the vehicle occupants. An automotive vehicle consists of many assemblies such as instrumentation panel, doors, sun/moon-roof, deck lids, hood, etc. which are the potential sources of BSR noise. The potential locations of critical BSR noise could be contained within such assemblies as well as across their boundaries. An extensive study is made regarding the overall structural behavior as well as their interaction under typical road loads to come up with enhanced design for improved quality from the BSR noise perspective. The alternative designs were comparatively evaluated for their relative noise level from buzz, squeak and rattle perspective using an analytical tool - N-hance.BSR. Critical noise sources both at the system as well as the assembly levels were identified and the relative noise levels were compared critically to determine the influence of the design changes on the BSR quality of the system and its assemblies. In this paper, a brief introduction is provided regarding the typical product background and the noise quality requirements, typical design changes that influence the BSR characteristics followed by a brief introduction to the software N-hance.BSR. The results of such a comparative design evaluation from N-hance.BSR are presented at the end. The observations of the critical squeak and rattle locations were confirmed by physical tests on the baseline and enhanced models."
Model Based System Development in Automotive,"The paper presents a major part of the STEP-X project (Structured Development Process by the example of X-By-Wire-Application in the automotive), namely a seamless, model based software development process in automotive engineering. Our process is model based and supported by a tool chain. The tool DOORS is used for requirements management and engineering whereas the CASE tool Artisan RtS based on the Unified Modeling Language (UML) and the CASE tool Ascet SD are used for specification and design purposes. Each of these tools has its particular strength in a certain design phase. We propose designing rules and modeling guidelines for the development of state based behavior which conforms to seamless model transformation in our tool chain. The rules are checked by an embedded rule-checker. Additionally we illustrate our approach in a case study on a subsystem of the Volkswagen car electronics. The case study is characterized by state-oriented and concurrent behavior as well as time and value-discrete information processing."
Challenges in Vibroacoustic Vehicle Body Simulation Including Uncertainties,"During the last decades, big steps have been taken towards a realistic simulation of NVH (Noise Vibration Harshness) behavior of vehicles using the Finite Element (FE) method. The quality of these computation models has been substantially increased and the accessible frequency range has been widened. Nevertheless, to perform a reliable prediction of the vehicle vibroacoustic behavior, the consideration of uncertainties is crucial. With this approach there are many challenges on the way to valid and useful simulation models and they can be divided into three areas: the input uncertainties, the propagation of uncertainties through the FE model and finally the statistical output quantities. Each of them must be investigated to choose sufficient methods for a valid and fast prediction of vehicle body vibroacoustics. It can be shown by rough estimation that dimensionality of the corresponding random space for different types of uncertainty is tremendously high. Therefore, a substantial reduction of the dimensionality is crucial. Next important step is to choose a proper method to model uncertainties and include them in the FE model. Here, many different methods are available: From well-known sampling based methods like Monte-Carlo to more sophisticated spectral methods like generalized Polynomial Chaos. Finally, the output of these simulations is not a single deterministic value but rather completely new results like mean value, variance and probability distribution. Therefore, the mindset has to change from comparing single deterministic curves and values to an evaluation of stochastic quantities and their relations. This new kind of output requires dealing with new demands as well as a new mindset from simulation engineers."
Concept Study on Windshield Actuation for Active Control of Wind Noise in a Passenger Car,"The windshield is an integral part of almost every modern passenger car. Combined with current developments in the automotive industry such as electrification and the integration of lightweight material systems, the reduction of interior noise caused by stochastic and transient wind excitation is deemed to be an increasing challenge for future NVH measures. Active control systems have proven to be a viable alternative compared to traditional passive NVH measures in different areas. However, for windshield actuation there are neither comparative studies nor actually established actuation concepts available to the automotive industry. This paper illustrates a comparative conceptual study on windshield actuation for the active control of wind noise in a passenger car. Making use of an experimental modal analysis of the windshield installed in a medium-sized vehicle, a reduced order numerical simulation model is derived. Possible actuation concepts are briefly recapitulated and a comparative, preliminary study assists the selection of possible actuation positions of the windshield. Two basic actuation concepts (i.e. an electrodynamic inertial mass actuator as well as windshield actuation by means of piezo-electric stack actuators) are investigated in detail and generalized design requirements are derived for both actuator types."
High Frequency Vibration Transmission Analysis on Agricultural Tractor by Using Combined Dynamical Energy Analysis and Transfer Path Analysis Approach,"Dynamical Energy Analysis (DEA) has recently been introduced as a mesh-based high frequency method modelling structure borne sound for complex built-up structures. Using DEA, the structure-borne sound of an assembled agricultural tractor was calculated and good agreement between measurement and DEA calculations has been shown. However, it is still difficult to model a solid structure as currently DEA is based on wave-transmission calculations through plates and plate-to-plate junctions. Additionally, it is often difficult to generate accurate FE meshes of assembled complex structures because of welds, bolts, and rubber brushes between components. In this paper, we propose a novel method to generate DEA elements based on measurement data in order to model solid parts of a complex structures. The method of Advanced Transfer Path Analysis (ATPA) is employed to extract energy-transmission characteristics of a structure. Firstly, Frequency Response Functions (FRFs) are measured between interface points on a structure. Then the direct transfer functions between all interface points are calculated using ATPA. Finally, DEA elements connecting interface points are calculated. They are based on the ATPA result and therefore represent energy-transmission characteristics of the structure. the proposed method is applied to an agricultural tractor structure in order to generate DEA-TPA elements of a gear casing demonstrating the effectiveness of the proposed method."
Vibration Energy Harvesting Damper in Vehicle Suspension,The road roughness is one of the main sources of a severe undesired vehicle vibration. The vehicle suspensions are the front lines of defense protecting the passengers and vehicle equipment from harsh vibrations caused by the ground road roughness. The recent tendency is to combine the process of vibration mitigation and additional electrical power generation. It allows scavenge the power from a vehicle’s vibrations and convert these vibrations into electrical power for use in vehicle systems. New Vibration Energy Harvesting Damper (VEHD) is based on author’s US Patents and consists of two main components: Tuned Mass Damper with automatic self-tuning properties and Generator of Electricity. The analysis of dynamical performance and effectiveness of developed rectilinear VEHD for Jeep Sport Wrangler vehicle suspensions is presented. Mathematical model of dynamical behavior is developed and the simulation analysis illustrates the direction of optimal parameter’s selection for getting VEHD with minimal mass. Test results demonstrate the efficiency of proposed VEHD and some new opportunities for their applications in vehicle suspensions.
Evaluation and Improvement of Greenhouse Wind Noise of a SGMW SUV using Simulation Driven Design,"At SAIC-GM-Wuling (SGMW) the greenhouse wind noise performance of their vehicles has gained a lot of attention in the development process. In order to evaluate and improve the noise quality of a newly developed SUV a digital simulation based process has been employed during the early stage of the design. CFD simulation was used for obtaining the flow induced exterior noise sources. Performance metrics for the quality were based on interior noise levels which were calculated from the exterior sources using a SEA approach for the noise transmission through the glass panels and propagation to the driver’s or passenger’s head space. Detailed analysis of the CFD results allowed to identify noise sources and related flow structures. Based on this analysis, design modifications were then applied and tested in a sequential iterative process. As a result an improvement of more than 2 dB in overall sound pressure level could be achieved."
CFD Water Management Design for a Passenger Coach with Correlation,"Side window clarity and its effect on side mirror visibility plays a major role in driver comfort. Driving in inclement weather conditions such as rain can be stressful, and having optimal visibility under these conditions is ideal. However, extreme conditions can overwhelm exterior water management devices, resulting in rivulets of water flowing over the a-pillar and onto the vehicle’s side glass. Once on the side glass, these rivulets and the pooling of water they feed, can significantly impair the driver’s ability to see the side mirror and to see outwardly when in situations such as changing lanes. Designing exterior water management features of a vehicle is a challenging exercise, as traditionally, physical testing methods first require a full-scale vehicle for evaluations to be possible. Additionally, common water management devices such as grooves and channels often have undesirable aesthetic, drag, and wind noise implications. Being able to detect water management issues such as A-pillar overflow, as well as to develop strategies to resolve them in parallel with early design cycle exterior aerodynamic development, is highly desirable for this reason. This paper details a collaborative effort where a CFD method is first validated against on road testing and then applied to a design study. The Lattice Boltzmann code based results presented show an excellent correlation with on-road test data. One successive design variants is created, with the design process being driven by the understanding provided by the CFD results."
Enhancing Driver Awareness Using See-Through Technology,"This paper presents a real-time application of see-through technology using computer vision (e.g., object detection) and Vehicle-to-X (V2X) communication (e.g., Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I)). Each access point (AP) was connected to Chattanooga’s fiber optics internet, supporting a data transfer rate up to 10-Gbps. Using a 5Ghz frequency, vehicular communications were set up with a seamless handover for transferring real-time data. Two web cameras acting as clients were mounted on the windshield of two of three vehicles to send image data to the offsite server. Using multi-threaded programming, both image feeds were processed simultaneously. Once the server received the images, it performed an object recognition algorithm on each image using a convolutional neural network (CNN). Post- identification, the images from the second vehicle were sent and overlaid dynamically to the third vehicle’s image. This repetitive overlapping of images allowed the third vehicle to “see-through” the second vehicle in real-time. This experiment was showcased during the US Ignite Smart Cities Summit in June 2017 to emphasize the benefits of drivers being able to “see-through” the car in front to make more intelligent decisions when passing a vehicle, stopping for a pedestrian, or seeing an upcoming detour due to construction before the view is within their line of sight. Using V2X communication with computer vision gives the driver a higher level of awareness and allows better decision making in the case of a roadway conflict, ultimately increasing the level of safety on our roadways."
"Application of CAE (Computer Aided Engineering) Superelement Technique for NVH (Noise, Vibration and Harshness) Attributes on a Trimmed-Body Vehicle Structure in Order to Assist Supplier Commodity Development Based Also on NVH Requirements","The business environment is ever changing, several innovations have allowed companies to transcend borderlines and become global entities. While the opportunities are numerous so are the challenges. In this fiercely competitive global marketplace, success requires companies to pay closer attention to supplier relations. The relationship between an automotive industry and its suppliers is an example of it, so the application of CAE (Computer Aided Engineering) superelement technique may improve, in terms of NVH (Noise, Vibration and Harshness), the vehicle development efficiency, without compromising confidentiality directives. Most of NVH requirements must be tracked through Transfer Functions (TFs) analyses at response points located on the Trimmed-Body Finite Element Model (FEM), as for example: Point Mobility, Vibration Transfer Function (VTF) and Acoustic Transfer Function (ATF). As the Trimmed-Body is an assembly of sub-systems, some of them developed in-house and other by external suppliers, FEM and TFs must be cascaded to all sub-system developers, including external suppliers. Confidentiality directives do not allow FE models sharing with external suppliers, precluding commodities development by suppliers to be driven by NVH attribute targets and requirements. Although the Global Static Stiffness is not a TF analysis, it is also considered part of NVH requirements. This paper shows how to obtain the static and dynamic reductions of the stiffness, damping, fluid-structure coupling, load and mass matrices of the Trimmed-Body FEM in order to generate a superelement representation with all design variables, as geometries, materials and properties hidden, with no reversal engineering possibility. It will allow external suppliers to develop their own sub-assemblies, considering NVH attribute targets and requirements. It is also part of this paper to propose the inclusion of superelements use on the engineering statement of work (SOW) in order to integrate the suppliers to all phases of new vehicle programs."
Restoring and Upgrading of a Ford Motor Company Reverberation Room Test Suite,"This paper presents the upgrades and improvements needed to bring an old and seldom used reverberation room test suite up to current standards. The upgrades and improvements included eliminating a below-floor pit that was open to the reverberation room, improving the acoustical diffusion within the room, enlarging the opening between the reverberation room and an adjacent anechoic chamber, renovating the anechoic receiving chamber, constructing an innovative sound transmission loss test fixture, and installing of a high power reverberation room sound system."
Evolution of Trim Modeling with PEM for Structureborne Noise Prediction in Full Vehicle,"The need in the automotive industry to understand the physical behavior of trims used in a vehicle is high. The PEM (poro-elastic method) was developed to permit an explicit representation of the trims in the FEM full vehicle models and to give tools to diagnose the effect of the trims and test design changes (porous material property, geometry, etc.,). During the last decade, the evolution of software and hardware has allowed the creation of models with highly detailed trim description (porous material using Biot parameters, plastic trims, etc.,). These models can provide good correlation up to 400Hz compared to measurements in contrast to classical NSM (Non Structural Mass) methodology which shows limitations. This paper will first introduce the classical method using non-structural masses, local masses and high values of acoustic damping to represent the trim which shows limitations for predicting the response above 200Hz and does not allow a detailed analysis of the effect of trims on the vibro-acoustic behavior of the vehicle. A review of the literature of the evolution of the modeling techniques for full vehicles with PEM representation of the trims is presented from early models with only some porous trims represented as PEM to the latest ones where most of the trim parts ranging from acoustic porous trim (dash insulator, absorbers, etc.,) to the elastic plastic parts (dashboard, pillar trims, etc.,) are included in the model. The influence of modeling accurately the coupling conditions between the trims and the inner cavity or the structure will be discussed. The different results available to diagnose the problems and the influence of the design improvements and visualize them via methods such as intensity contour plots will be introduced."
Non-Linear Dynamic Analysis of a SuperPlug™ Door Module Response to a Door Slam Event,"The SuperPlug™ door module is a new Delphi innovation. It is a one-piece composite structure, which integrates several door components into one assembly. This reduces the total part count, simplifies the vehicle level assembly process, and reduces labor cost (see the Appendix). The door slam durability test is an important factor in door module design. As more hardware is integrated into the SuperPlug, this subsystem performance in a door slam test becomes important. Therefore, the correct placement of components and the supporting structure is critical. Currently, the evaluation of door slam durability for the SuperPlug is a process of build then test. This is time consuming and costly due to a long testing lead-time and the expense of tooling a new mold. It was realized that a numerical process for assessing the effect of door slam would be required. This process would compute the dynamic response using finite element analysis (FEA). The first attempt within the Doors Systems group to simulate door slam used static FEA [1]. It was based on the assumption that the maximum dynamic loads could be modeled as point forces at the center of gravity of each component. This approach had the advantage of producing results quickly. However, the results are not considered realistic because factors like inertia, time and contact were not included in the analysis. It was then recommended to apply dynamic FEA methods that can consider these factors. This paper is a summary of a master’s degree thesis work on door slam [1]. It will describe how dynamic FEA was used to determine the response of a SuperPlug to a door slam. Discussion on how the FEA results compare with door slam tests will be presented."
Autoliv’s Sound and Vibration Laboratory for Automotive Safety Component Development,"The new sound and vibration laboratory at Autoliv’s Ogden Technical Center (OTC) was purpose-built with a focus on automotive safety restraint product development (air bags, seat belts, steering wheels, etc.). The laboratory requirements stem from the continued industry trend of quieter vehicles which drives the need for components with extremely low levels of rattle noise. The laboratory at OTC complements similar Autoliv testing facilities around the world. Test articles range from several cubic inches up to approximately one cubic foot and contain varying degrees of moving elements. With the new laboratory at OTC, Autoliv can test new product designs earlier in the development process and obtain test results and feedback faster. The function of the OTC test lab is vibration-induced rattle noise; shake components with a known input and measure the resulting noise. To provide an acceptable signal to noise ratio, the new laboratory was designed to have a 25 dBA re 20 μPa noise floor, reasonable Transmission Loss though the various partitions, modest internal reverberation control, and an ultra-quiet electrodynamic shaker. Achieving these goals required a site acoustic and vibration survey during the project planning phase, the results of which were compared to the performance criteria to drive the various architectural decisions. The resulting facility is capable of generating, recording, and analyzing the target sounds without concern for noise contamination. With this high quality vibro-acoustic information, design decisions can be made early in the product design cycle."
The Noise and Vibration Response of Eight Light Vehicles on Sinusoidal and Conventional Rumble Strips,"Noise and vibration measurements were conducted on eight light vehicles ranging from small compact passenger cars to a large sport utility vehicle on and off shoulder rumble strips of two different designs to assess the input to a vehicle operator when the vehicle departed from the travel lane. The first design was a more conventional design, consisting of cylindrical indentions ground into the pavement at regular 30 cm intervals, and a continuous sinusoidal profile with a peak-to-peak length of 36 cm. Triaxial vibration measurements were made at six locations, including the steering wheel and column, the seat cushion and track, and the front and rear spindles. Interior noise was measured at six locations, one at the operator’s outward ear and five at the front seat passenger (three in the fore/aft locations of the seat and at outboard and inboard ear locations). In addition to the in/on vehicle measurements, pass-by noise levels were made. The measurements were performed at 97 km/h and 72 km/h. The primary purpose of the measurements was to develop a recommendation for a standard rumble strip evaluation procedure that could be implemented by transportation agencies to assure comparable results when considering rumble strip designs that produce minimal exterior noise while maintaining sufficient warning input to the vehicle operator. This research did reveal some markedly different results between the test vehicles in both interior noise and vibration as well as pass-by noise. In this paper, these results are presented, and initial draft test procedures are reviewed."
Practical Uses for Road Noise Cancellation,"Today’s automotive customers have come to expect luxury and electric vehicles to be quiet and refined pieces of machinery. As customers have come to expect powertrain cancellation in most vehicles today, they are also increasingly looking for a reduction in road noise to improve their overall perception of luxury and electric vehicles. While the field of noise cancellation is ever expanding, several auto makers are exploring the possibility of introducing a real time Road Noise Cancellation (RNC) system to meet these customer expectations. An RNC system can be integrated into the vehicle infotainment system and be utilized to either noticeably reduce or shape the vehicle noise floor. This paper will look at the current traditional Noise and Vibration (N&V) methods of reducing road noise and then also the benefits associated with actively controlling the amount of road noise using an RNC system."
Human Resources Integration Master Plan: A Response to Revolving Door Management,"Taylor (1999) reported the effects of national cultures on the work values of aviation mechanics and Patankar (1999) reported the effects of their professional and organizational cultures. Taylor and Patankar (1999) found effects of national and professional cultures on the outcomes of maintenance human factors programs. Considering those effects, this paper focuses on a strategy that would encourage the champions of human factors programs to develop a human resources master plan and integrate it with the organizational culture."
Structural Modules with Improved Crash Performance Using Thermoplastic Composites,"A new group of composite materials “Advanced GMT” which are used for the economic production of light weight complex shaped parts in the automotive industry are presented. Advanced GMT consist of a combination of different technical textiles such as woven or stitched fabrics and non-woven mats which are impregnated with a polypropylene resin to a laminate. The laminate is flow molded to complex shaped components with a total cycle time of 30 to 60 seconds using standard equipment. The use of advanced GMT for weight saving and performance improvement of structural modules is discussed. Examples of such modules include hatchback or side door modules, front-end modules, bumper beams with integrated energy absorbers (crash cones) or spare wheel wells and structural elements in the power train. Common for all these type of modules or components is the need for geometric freedom in the design, crash worthiness including high specific energy absorption and ductile failure behavior, structural stiffness and economic production of large series. A case study of a side door module is presented. Aspects of the functional integration is shown with the complex features of the part allowing mounting of several elements such as side window railings, the lock, speakers etc. The versatility of advanced GMT is shown by a comparison in the crash behavior of the door module. The addition of local reinforcement of advanced GMT to a GMT structure increased the crash energy absorption with 300%, without weight increase."
A Discussion On Using A Pendulum as a Method for Impact Testing Vehicle Sub-Systems,"The purpose of this paper is to discuss the use of a pendulum as a repeatable method for impact testing vehicle subsystems and components. Tests on three different vehicle subsystems are presented as examples of impact testing that has been performed using a pendulum. Impact testing on two different roll bar designs to compare effectiveness, impact testing on various van side cargo doors to compare door latch integrity, and impact testing on various fuel tanks to compare the integrity of the fuel tank with and without shields installed. These tests were not intended to replicate the forces, energy, or impact pulse on the vehicle in the actual collision but rather evaluate how the vehicle subsystem reacted to impacts that were similar to that which occurred in the collision. Using proper instrumentation, it can be used to determine the forces or energy required to cause a localized failure or event, determine if an engineered solution has corrected the problem, and used to compare one design to another."
Material and Design Innovation Techniques for Expanded Polypropylene (EPP) Products Used in Automotive Interior Applications,"The use of Expanded Polyolefin foams including Expanded Polypropylene (EPP) material for interior applications has grown over the years to include applications throughout the vehicle. The demand for weight and cost reduction has forced designers to seek out the most versatile material available to satisfy the need for performance, durability, as well as design flexibility. The role of light-weight materials such as EPP has expanded. As such, the design challenges have also enabled the use of EPP in applications requiring energy management, as well as structural, acoustic, and storage/stowage functions. This paper will review the design guidelines that enable EPP to be used in numerous automotive interior applications. As EPP foam becomes more widely specified, and as the applications become more multifunctional, it is important to understand the potential solutions available to satisfy all aspects of design, performance, quality, and safety. Recent material developments and innovations allow for EPP to be specified in a wide range of densities, and with a variety of surface finishes and textures, as well as surface properties that allow it to be used in applications subject to NVH (Noise, Vibration and Harshness) requirements, and those requiring material compatibility. Technical innovations now allow for material optimization, which enable EPP to conform to the stringent performance requirements and BSR (Buzz, Squeak and Rattle) guidelines for today's automotive interiors. Performance can be affected using either mechanical or chemical solutions to satisfy OEM requirements. This paper will also highlight current production examples of EPP applications and their latest design and performance characteristics. Examples of recent performance studies will be cited; including graining and textured surfaces, acoustic enhancements, low friction solutions, and molded part operational and attachment methods."
Advanced Source Localization Techniques Using Microphone Arrays,"Microphone arrays used in vehicle acoustics are mainly designed for fast setup and basic evaluation (e.g. using delay-and-sum beamforming) resulting in a restriction to free field environments. Applications in vehicle interiors require advanced source localization techniques taking into account the reflections at the different panels appearing as mirror sources. Coherence filtering techniques allow for the detection of these mirror sources. An additional sensor is placed as a reference close to the main source. This reference signal is used to filter the array signals increasing the overall dynamic range of the acoustic source mapping. The discrimination of the original source and the reflections is obtained by manipulating the impulse responses between the reference signal and all microphone signals. Other advanced signal processing techniques can be used to increase the limited dynamic range of conventional beamforming such as principal component analysis removing the dominant sources. An implementation allowing for online application based on spatial filters will be presented. In addition the production requirements of large scale arrays, for example wind tunnel measurements and pass-by or fly-over measurements, are discussed. Manufacturing a large scale array with an appropriate precision for the microphone positions and the video system would be very expensive. A very efficient solution turns out to be a combination of a small calibrated camera module (consisting of a video system plus a small number of microphones with high-precision positioning) and a large scale array containing microphones with low-precision positioning. Array measurements using a standard loudspeaker for excitation serve as input for nonlinear optimization techniques to identify the positions of all microphones based on the orientation of the camera module. The techniques also allow for combining small arrays to increase the spatial resolution. This paper describes the theoretical background of different source localization techniques based on microphone arrays. Application examples are used to illustrate not only their advantages but also their potential drawbacks."
Evaluation of Ground Vehicle Wind Noise Transmission through Glasses Using Statistical Energy Analysis,"The contribution of wind noise through the glasses into the vehicle cabin is a large source of customer concern. The wind noise sources generated by turbulent flow incident on the vehicle surfaces and the transmission mechanisms by which the noise is transmitted to the interior of the vehicle are complex and difficult to predict using conventional analysis techniques including Computational Fluid Dynamics (CFD) and acoustic analyses are complicated by the large differences between turbulent pressures and acoustic pressures. Testing in dedicated acoustic wind tunnel (AWT) facilities is often performed to evaluate the contribution of wind noise to the vehicle interior noise in the absence of any other noise sources. However, this testing is time-consuming and expensive and test hardware for the vehicle being developed is often not yet available at early stages of vehicle design. In addition, modifications of the vehicle exterior geometry that may be beneficial to interior noise are often difficult to implement during the testing or to evaluate properly via test. This paper describes a test-based approach to measuring and understanding the contribution of exterior wind noise to the interior cabin noise through the individual glasses and the development of a correlated Statistical Energy Analysis (SEA) model capable of predicting the effect of a design change to any combination of thickness or material changes to the glasses. AWT testing was performed with interior microphones, accelerometers on the glasses, and arrays of flat exterior pressure transducers to establish the acoustic and structural-acoustic transfer functions to the interior. An underbody skirt, extensive taping of exterior gaps, and “blocker” parts on the interior of the glasses were used in order to isolate the noise contribution through individual glasses. Two versions of the front side glass -monolithic and laminated - were tested to compare the effect of the glass material and damping on transmitted wind noise and to provide a reference from which the wind noise load at this important location could be inferred. The data set from this testing was processed and used to correlate an SEA model of the test vehicle capable of being used for design studies of the effect of the glasses on the interior wind noise."
Progress in Aeroacoustic and Climatic Wind Tunnels for Automotive Wind Noise and Acoustic Testing,"There has been significant progress in developing test facilities for automotive wind noise and automotive components since the early 1990s. The test technology is critical to the development of modern vehicles, and essentially every major automotive manufacturer owns and operates their own aeroacoustic wind tunnel, or has rental access to one and conducts a significant amount of wind noise testing. The current status for climatic wind tunnels is that many new CWTs are being defined with acoustic test requirements. These test capabilities in AAWTs and CWTs will continue to enable the development of vehicles with better wind noise attributes, fewer problems with sunroof ‘booming’, and lower noise levels for HVAC and auxiliary systems. In the future, it is expected that the test demand for AAWTs and CWTs with low acoustic background noise will continue to increase as customers expect better automotive products, especially across more of the product line. The objective of this work is to present some of the progress and challenges involved in designing wind tunnels with low background noise in order to meet the requirements of automotive companies for their product development needs."
Miga Aero Actuator and 2D Machined Mechanical Binary Latch,"Shape memory alloy (SMA) actuators provide the highest force-to-weight ratio of any known actuator. They can be designed for a wide variety of form factors from flat, thin packages, to formmatching packages for existing actuators. SMA actuators can be operated many thousands of times, so that ground testing is possible. Actuation speed can be accurately controlled from milliseconds to position and hold, and even electronic velocity-profile control is possible. SMA actuators provide a high degree of operational flexibility, and are truly smart actuators capable of being accurately controlled by onboard microprocessors across a wide range of voltages."
Automotive Engineering: January/February 2021,"Gearing EVs for greater efficiency Ingear, an innovative 2-speed transmission born in Canada, aims to unlock electric-vehicle performance and efficiency. Built-in Google vehicle apps arrive Android Automotive OS opens the door, cautiously, for third-party developers. Riding on air: Activated carbon aims at autos An old piece of science is set to bring new applications across the mobility spectrum. Allison builds a testing powerhouse Allison Transmission's new Vehicle Environmental Test center in Indianapolis is open for business for external and in-house customers alike. The VET has everything vehicle development teams need to improve testing efficiencies. Editorial The EVs are coming. Now what? SAE Standards News SAE J3178 Information Report for battery adhesives, sealants available Supplier Eye On my 2021 radar What We're Driving CES 2021: GM creates BrightDrop electrified delivery and logistics company Magna execs warn of impending EV complexities Hyperscreen brings new meaning to 'widescreen' display Dana's twin-clutch axle boosts Ford Bronco Sport's off-road cred Sparkling RWD platform underpins Genesis GV80 Nissan's 2021 Rogue is a COVID beater"
"Noise, Vibration and Harshness of Electric and Hybrid Vehicles","The noise, vibration, and harshness (NVH), also known as noise and vibration (N&V), is a critical feature for customers to assess the performance and quality of vehicles. NVH characteristics are higher among factors that customers use to judge the vehicle's quality.This book sets out to introduce the basic concepts, principles, and applications of the NVH development and refi nement of Battery Electric Vehicles (BEV), Hybrid Electric Vehicles (HEV), and Fuel Cell Electric Vehicles. Each type comes with its own set of challenges."
Passive Noise Reduction Possibilities for Trucks,"Passive noise reduction decreases the transmission of noise and vibrational energy without altering or changing the noise generating components and mechanisms. The lessening of the transmission of noise and vibrational energy is achieved through the use of noise control materials and parts which provide vibration damping, insulation, or sound absorption. Noise sources radiate sound power and vibrate. The airborne noise propagates to the exterior and causes a particular maximum “A” weighted level to be measured during pass-by tests. Exterior or pass-by noise, and interior or in-cab noise are the two major noise problems for trucks. The major tasks of soundproofing a truck include the definition of treatments for exterior and interior noise and the choice and application of damping insulation and absorption materials in the cabin and engine compartment."
The Building and Test-Track Evaluation of an Aluminum Structured Bertone X1/9 Replica Vehicle,"A vehicle build and evaluation program to demonstrate the feasibility of Alcan's Aluminum Structured Vehicle Technology (ASVT) is described. Five replica Bertone Xl/9 sports cars have been built on the production manufacturing facilities of Carrozzeria Bertone in Turin. The all-aluminum alloy body structures were produced with strength and stiffness equivalent to production steel bodies but with a weight reduction of approximately one third. Modes and frequencies of vibration, interior noise characteristics and 30 mph barrier test results for vehicles with aluminum and steel bodies are compared. High load input, 1000 mile pave and accelerated corrosion tests have proved the vehicles' durability."
Analysis of the Sound Field in an Automobile Cabin by using the Boundary Element Method,"A method of analyzing the three-dimensional sound field in a full-size automobile cabin was studied. The acoustic resonant frequency and the acoustic mode of the cabin were calculated by using the boundary element method (BEM), and were then compared with an experiment conducted on a full-size cabin model made of plaster. The calculated resonant frequencies agreed with measured ones to within about 3% below 170 Hz, and the calculated modes and frequency response curves were in good agreement with experiments when the cabin wall was rigid. In the case of a wall partially lined with absorbing materials, the calculated resonant frequency and the damping ratio were approximately the same as the experimental ones. From these studies, it is concluded that the BEM is useful for analyzing the sound field in a full-size automobile cabin."
Insulating Glazing in Side Windows,"The main problem with the car climate while running is thermal asymmetry on the human body. This asymmetry is caused by solar radiation, drafts from cold air and drafts due to radiation from cold surfaces. During winter, the cold surfaces of the side windows are a major source of discomfort, not only because of the above-mentioned cold radiation towards the outer upper body parts, but also as a result of the air stream needed for demisting the windows. This air stream has a very low temperature when reaching the B-pillar, where it easily deflects, hitting the driver's/passenger's shoulder. In order to avoid these problems, tests have been carried out with side-lights consisting of two hermetically sealed panes with a small air space in between. It was found that the surface temperature is significantly raised, by some 15°C, at low ambient temperatures. Not only are the heat losses reduced, but mist formation is also prevented. Negative aspects are weight and cost. For future development, chemically tempered glass might create possibilities for lighter solutions."
Environmental Influence on the Acoustic Performance of OEM Automotive Loudspeakers,"Automotive audio systems and loudspeakers are typically designed, evaluated, and optimized, for best acoustical performance under indoor laboratory testing conditions. Review of the current loudspeaker engineering test standards, including those published by the car manufacturers, confirms this. Environmental testing is limited primarily to accelerated life tests which are subjective in analysis and often destructive. Although there are some post environmental test requirements for irreversible changes to acoustical performance, there are no requirements on how much the acoustical performance of loudspeakers may change while exposed to either high humidity or non - temperate temperature conditions. The effect of humidity and water on the acoustical performance of today's “waterproof” automotive loudspeakers is shown to be potentially audible. Recommendations are made for designing more environmentally robust automotive loudspeakers."
Time Delay Imaging for Automotive Sound Systems,Delayed arrivals of a stereo source are manipulated to suppress undesirable vehicle cabin acoustics and replace them with optimum acoustics for reproduction of commercial recordings. These optimum playback acoustics are derived from concert hall and listening room measurements. An experimental vehicle sound system implementing these concepts is described.
Towards an Objective Estimate of the Subjective Reaction to Diesel Engine Noise,"A microcomputer-based analyser is being developed to estimate subjective reaction to noise from diesel-powered road vehicles. An interactive technique is envolving to match certain combinations of objective measurements to the subjective preferences of individuals, using a control signal from the microcomputer. For a pilot experiment on diesel engine noise at cold idle conditions, the sound stimuli were obtained from engine surface vibration signals. The pilot experiment results suggest that the impulsive characteristic of the sound could be more important than the overall level."
Applications of Shape Memory Alloys in the Transportation Industry,"Shape memory alloys (SMAs) - which have the ability to change from a “deformed” state to an original “remembered” state when triggered thermally - offer engineering properties available in no other material. Their potential has not been fully exploited. Existing applications for SMAs in the transportation industry include electric fog lamp louvers and a device to reduce rattling noise in manual transmissions. Future applications in the transportation industry include the use of high density, zero insertion force electric connectors, which are capable of withstanding extreme shock and vibration."
New Concepts for Acoustic Material Selection,"Significant developments in moldable noise reduction materials will allow design engineers of off-highway equipment to incorporate molded parts concepts into their design schemes for both the cab and engine compartments as their use of contoured shapes continues to increase. When properly designed, and used in conjunction with complementary treatments which have been carefully selected on the basis of proven acoustic test criteria, molded sound barriers and sound absorption parts are more cost effective than the oft seen overkill of conventional materials."
Aerodynamic Characteristics of Subaru XT,"In recent years much more attention is being paid to aerodynamics, resulting in vehicles that are far more highly refined aerodynamically emerging one after another. SUBARU's belief is that aerodynamic design of such vehicles should be well balanced with engine cooling, aerodynamic noise, field of view, dirt splash and other aspects and should not impair roominess, driving comfort, safety, and other requirements while properly controlling aerodynamic force. At SUBARU, vehicle aerodynamic design usually takes the following steps. First, 1/5-scale models are built and the aerodynamic characteristics of the actual vehicle are evaluated mainly based on such models. This is followed by building full-scale models with which equipment, underfloor, and other details are subjected to further evaluation, and thus development is promoted."
Experimental Research on Vibratory Properties of an Engine Hood,"A method and measurement system are developed for the experimental determination of vibratory properties of complex structures and applied to the determination of the engine hood for the passenger car “ZASTAVA”. Using a mechanical transfer impedance, the vibratory properties and damping factors are determined. The driving force at one point and the velocities at different points of the engine hood are measured. The vibratory properties of the engine hood have been analyzed and compared with regard to the stages of production completion: (1) engine hood without reinforcements, paint, and anti-rumble material; (2) engine hood without paint and anti-rumble material; and (3) engine hood complete. In all cases the engine hood was mounted on the nude car body for testing. Three levels of constant sinusoidal vibration force were applied in the middle point of the engine hood. The results are given in the form of velocity-frequency curves (velocity spectrum) for different measured points, force levels and different assembly stages in production. The hood reinforcements resulted in decreased output velocity levels of a factor between 2.0 and 2.5. On the other hand, the increase of the stiffness of the engine hood structure shifts the resonance frequencies and extends the peak outputs toward lower frequencies. A method for determination of the damping factor and relative damping are presented. By applying the anti-rumble material noise levels decreased by 1.0 to 1.5 dB(A). The output vibration levels decreased as well."
Acoustic Analysis of a Light Truck Cab,"Acoustic analysis of a Light Truck cab in the frequency range of 0 to 140 Hz was performed by utilizing an analytical method combined with experimental data. The structural and acoustic modes of the cab were determined by utilizing the MSC/NASTRAN dynamic analysis capability. Chassis, powertrain, and suspension components were simulated with the experimental modal data, acquired from dynamic testing of an actual vehicle. Triaxial transfer functions were obtained at all six cab-mount locations due to shaker excitation at the pinion nose and the 4 spindles, as well as neutral engine run-ups. The overall system model was constructed by combining analytical structural and acoustic modes with the experimental modal data using the modal synthesis technique and an in-house developed computer code called MOTRAN. The acoustic mode shapes, response at critical cab-structure locations, and interior sound level at the driver's ear were obtained. After the validity of the model was shown, the model was used to improve the acoustic response of the cab structure in terms of noise-related problems such as boom and drone. A new post processing method was developed to identify and determine the effects of ""panel deadening"" on the acoustic response of the vehicle. After extensive analytical iterations, an effective set of structural improvements were determined, and the recommended design modifications implemented on the vehicle. Subjective and objective evaluations were conducted to verify that the noise characteristics of the cab structure were indeed improved with the proposed design change."
Effect of Glass Angles on the Cooling Loads of Automobile Air Conditioners,"The characteristics of the directional total transmissivity of solar insolation through the glass panels of windshield, backlight and windows of automobiles are presented. The effect of the glass angles on the interior air temperature of the automobiles and the cooling loads of their air conditioners are discussed."
Car Crash Tests of Ejection Reduction by Glass-Plastic Side Glazing,"1983 ejection statistics are reviewed; half of the passenger car ejections, some 36,000 people of whom 5,346 died, are through glazing areas. Previous work has shown the remarkable strength of thin plastic coatings, developed for windshield anti-laceration applications, when applied to the inside of tempered glass side windows, in reducing ejection. In the present work, two tests were made, each with the NHTSA Moving Deformable Barrier (MDB) at 39 mph and all four wheels turned at 26 degrees, striking a stationary Volkswagen Rabbit in a perpendicular impact. The Alfred I. DuPont de Nemours Company provided the plastic coating on tempered glass side windows. The plastic layer extended beyond the sides and top of the glass to be wrapped around steel strips bolted to the window frame. On vehicle impact, the tempered glass broke, but the pieces were held in place by the plastic layer, which then deformed outward as a “safety net” with head contact. In the first test, with a low and short striking vehicle hood line simulation, the top of the door bent out as the bottom was pushed in, and the head bulged the glazing out to hit the elevated base plate of the MDB, although the “safety net” held. In the second test, with a more typical vehicle hood line effect simulation, the “safety net” again held, giving a HIC of 616. A window design to allow window up and down motion with the plastic layer movably secured with a “T edge” in the window channel is under construction. An eight inch sphere Glazing Test Device is being developed, with a skin simulation / chamois coat on the lower hemisphere for laceration measurement, accelerometers for Head Injury Criterion (HIC) measurement, and a weight variable from 10 to 20 to 40 pounds, for ejection reduction measurement. This paper presents the views of the authors, and not necessarily those of the National Highway Traffic Safety Administration (NHTSA). The numbers in parentheses are the references, listed at the end of the paper. This paper is dedicated to the memory of Henry H. Wakeland, late of the National Transportation Board, who was instrumental through his work in New York in establishing government efforts to build experimental safety cars, and to the memory of William Haddon, Jr., M.D., late of the Insurance Institute of Highway Safety, who taught the world that automobile safety is one of the most important areas of preventive medicine, and that cars could be built, passively, not to harm. Both of these giants of automobile safety research died in early 1985."
Ground Testing Approach for the B-1B Bomber,"Existing methods for production ground testing the B-1B would create an undesirable and cumbersome work environment. The noise generated by the equipment along with hoses, cables and ducts on the floor produce a safety hazard. The information presented here deals with a new approach to meet the aircraft delivery rate requirement. Goals were established and a review of existing methods provided the “stepping stones” to the solution. The use of high technology computer applications is discussed along with the equipment types used on the B-1B bomber. This is the first automated approach to ground testing and checkout of complex aircraft mechanical systems."
The NCSU Low Speed Boundary Layer Wind Tunnel,"Procedures employed for the design of a new low speed boundary layer wind tunnel are described. The tunnel is a semi-open circuit facility for the study of large scale two-dimensional boundary layers with or without pressure gradients, A large plenum box is used as a replacement for a diffuser, 90 degree turn and noise attenuation chamber. The modular test section is seven meters long and capable of velocities from 5 to 33 m/sec. Experimental data to evaluate the tunnel performance are also described."
An Application of Structural-Acoustic Analysis to Car Body Structure,"In order to calculate efficiently the characteristics of car body vibration and the acoustic characteristic of the passenger compartment, a structural-acoustic analysis system, ‘CAD-B’, was developed. This system divides the body into three components - front body, main cabin and rear body. The characteristics of front and rear body vibration are expressed in modal parameters. The vibration characteristic throughout the car body is then calculated through the building block approach, while the main cabin remains in finite elements. A good agreement in eigen pairs was seen between this approach and the conventional finite element method. As for the passenger compartment, it is divided into finite elements and its eigen pairs are calculated. Then by linking body vibration with the acoustic characteristic of the passenger compartment, sound pressure in the passenger compartment is calculated. Since in the CAD-B system, the contribution of each panel vibration to sound pressure is calculated and displayed, the parts of the panel to be deadened are derived quickly. This approach has been applied to the problem of road noise reduction, and resultantly, interior noise could be reduced by using only a small quantity of sound deadening material. Some floor panel modifications to reduce noise were also made."
Hem Flange Evaluation of Corrosion Performance,"Field or service testing is the best procedure for evaluating the corrosion resistance of any material. However, in the development of a new product, complete service testing and long atmospheric exposure are impracticial due to the time required to develop data. Historically, the accepted method for accelerated testing has been the ASMT-B117 Salt Fog Test. Unfortunately, many investigators have found that salt fog test results do not correlate with field performance. For example; a light weight electro galvanized steel would be unacceptable based on only salt fog results, while field experience shows it to be marginally acceptable for a three to five year period. With a goal of approximating the conditions inside a car door, an investigation was undertaken to modify the current exterior paint scab cycle test to more closely match actual field conditions. This paper will cover how we developed our cycle test and correlation of our results with actual automotive performance."
A Study of Vehicle Interior Noise Using Statistical Energy Analysis,"The noise and vibration of an automotive vehicle is studied using Statistical Energy Analysis (SEA). Three sources of interior noise - the engine, tires, and air flow - have been measured and used as inputs to the SEA model. The flow of acoustic energy through various structural components is calculated in order to determine the dominant paths of noise transmission to the passenger compartment. The predicted interior noise levels are compared to those measured under different operating conditions. The SEA model also evaluates the expected variation of the interior noise as the result of changes in the design configuration of the vehicle."
Unconstrained Layer Damping and the Use of Modified PVA as a High Efficiency Lightweight Material,"A lightweight polymeric visco-elastic sheet material has been developed called ‘Dedpan’ (thickness 600 micron, surface weight 1.25 Kg/m2). It exhibits excellent vibration damping performance when used as an unconstrained layer on sheet metal panels. Geiger plate decay rates of 26 dB/sec have been measured. The sheet is flexible, non-toxic, and meets automotive and building flammability specifications. The material composition is stable under paint stoving conditions (temperature up to 200°C), and the product has a tendancy to drape form to underlying structures when hot. These properties make it ideally suitable for the vibration deadening of automobile body panels."
"Motorist Head and Body Impact Analysis, Methodologies and Reconstruction","Motorist impact marks and embossments provide valuable data relating to evaluation of injury, crash energy management, occupant positioning and collision severity. Research techniques presented enable analysis of these impacts. Biomechanical techniques for motorist head impact analysis are presented along with static crush calibration and dynamic impact replication of passenger compartment head dents. Evaluation and identification of occupant induced marks on restraint systems are discussed as well as determination of who was driving. Ejection findings of the fifties and sixties are clarified by case studies that show how vehicle design changes may switch the portal of ejection from doors to windows."
Evaluation of Vibration with Respect to Human Response,"Methods of quantifying vibration with respect to human response are fully defined. The procedures may be applied to all types of vibration: multiple-axis and multiple-input motions which are steady-state, random or transient. The procedures are based on experimental research and have been applied to predict the discomfort, annoyance, health risks, interference with activities and motion sickness associated with vibration measured in a wide range of environments. The general method involves the assessment of 12 axes of vibration (the 3 translational and 3 rotational axes on a seat surface, the 3 translational axes at the seat back and the 3 translational axes at the feet). The method may be simplified so as to include only those axes of interest in specific environments. A scale of approximate discomfort, an ‘action level’ guide to the prevention of health effects, magnitudes of vibration which may interfere with activities, and a means of predicting the probability of motion sickness are provided. In all cases the frequencies, axes, locations and durations of the motions responsible for adverse effects can be identified. The application of the procedures to evaluate measurements in vehicles, assess computer predictions of vehicle vibration and optimise seat dynamics is described."
Occupant Comfort Requirements for Automotive Air Conditioning Systems,"This paper will describe - 1. Occupant comfort levels of 7 production vehicles when evaluated under “real world” owner test conditions, 2. Effect of film on glazing surface for interior vehicle temperature. The stylist who designs vehicles to sell must consider what imposition they have placed upon the a/c engineer. Tumble home glass surfaces and large areas increase the greenhouse effect on passenger comfort, whether it is in Michigan or the Southwest desert. Today, the automotive industry is a world market and the products must meet the demand of the owner. Sun Test Engineering has run an a/c evaluation program to determine their level of performance on various a/c products in Phoenix. Arizona the last several years. In the summer of 1985, 17 vehicles were evaluated for customer usage test and the results of 7 vehicles are present in this paper. Additional test programs were conducted on the effect of film applied to the glazing surface."
A Free-Flight Headform Impact Device for Evaluating the Energy- Absorption Characteristics of Vehicle Interiors,"This paper reports on the design, development, and use of a test rig that enables the analysis of the aggressivity of vehicle interiors to the heads of occupants. The equipment comprises a pneumatically controlled free-flight headform device. It can be positioned inside the passenger compartment of any passenger car via any normal window or door aperture. The device fires a simulated headform prescribed in SAE J984 at speeds for 10 to 30 mph. The enormous degree of flexibility in positioning enables impacts to be conducted on almost any part of the vehicle interior. Currently, energy-absorbing characteristics of the interior of passenger cars are assessed using drop rigs or pendulums, which necessitate the dismantling of the vehicle body. This has implications for representativeness in terms of the validity of the stiffness characteristics of the section of the vehicle being tested. The results of testing standard specimens, using all three test devices, are presented and discussed."
Materials Substitution in Automotive Interiors,Automotive interiors are evolving in the direction of increased: Luxury Passive occupant crash protection Acoustic and vibration isolation Electronic instrumentation Warranty life
The Future of Random Vibration Screening and Testing in Automotive Engineering,"Emphasizing stimulation (using random vibration and thermal shock), this paper first examines ESS (environmental stress screening), a relatively recent electronics production tool. Then it emphasizes simulation (of over-the-road random vibration), environmental laboratory testing during development. While different in their immediate objectives, the two subjects have a common goal: increasing the reliability of vehicles and their onboard electronic and other assemblies."
An Overview of Automotive Interior Glass Light Scattering Film,"Light Scattering Films (LSF) on automobile interior glass surfaces were studied on 35 vehicles. The principal chemical compounds that caused the LSF were identified along with the primary sources for these chemicals. The LSF composition and amount found on the windshields exhibited extreme variability. The causes of this variability are discussed. The health and safety of the occupants exposed to the extremely low levels of volatile airborne precursors of the LSF were also studied. Finally, the techniques are presented to: Measure the tendency of a material to contribute to the LSF. Characterize the composition of the LSF. Minimize the LSF in future automotive interiors."
Simulation of Road Crash Facial Lacerations By Broken Windshields,"The facial laceration test has been proposed as an addition to the dummy injury criteria of Federal Motor Vehicle Safety Standard 208. To better understand laceration conditions as they actually occur, three road crashes of increasing severity, all involving facial laceration by the broken (cracked) windshield and one involving partial ejection, have been simulated physically and analytically. The physical simulations used vehicle test bucks, the Hybrid III head with the chamois facial coverings of the facial laceration test, and a piston - constrained Head Impactor. Computer simulations of the three crashes were also carried out using the CALSPAN 3D “CVS” and the 2D “DRISIM” computer programs. The computer simulations provide insight into the effective mass of the head and body on windshield contact, and the forces, velocities, and accelerations involved. The computer simulations show how the impact velocity and effective mass of the head can be much higher than expected, due to body kinematics and loading of the head by the body during windshield contact. These simulations help explain accidents in which the windshield was broken by head contact in a 7.5 km/hr (5 mph) crash, and in which the head was partially ejected in a 21 km/hr (13 mph) crash. The physical simulations approximated the damage observed in the three accidents. In addition, the reduced laceration and potentially reduced ejection by the use of glass-plastic glazing was demonstrated. This paper presents the views of the authors, and not necessarily those of the National Highway Traffic Safety Administration."
Interior Noise Control of the Saab 340 Aircraft,"A comprehensive development program was performed on the Saab 340 aircraft, with the goal of reducing sound levels at the passenger seats in the plane of the propellers. The test program included in-flight sound measurements and operating deflection shape measurements on the fuselage structure, for various propeller speeds and synchrophase angles, and structural frequency response tests. The noise control approach developed was to reduce the low-order fuselage response with the addition of viscoelastic tuned dampers to the fuselage frames in the plane of the propellers."
20 Questions About Acoustics in Industry,"The potential contributions of acoustical technology to manufacturing companies pervade nearly all of its functions from marketing and product planning to design engineering and quality control. Despite this, however, companies generally feel uneasy when they embark on programs to use acoustics in their operations because the technology seems complicated and somehow harder to “get a handle on” than it is in other cases. But the issues of product sound, and the benefits of acoustics on a diagnostic tool are too important to ignore, so in this paper we discuss these issues in a “20 questions” format to help planners, engineers and managers as they proceed to implement acoustical technology in their organizations."
Acoustical Measurements for Automotive Sound System Evaluation Using Time Delay Spectrometry,Over the last few years significant emphasis has been placed on the design of automotive sound systems having proper spectral and spatial performance. But often the frequency response of such a system is subjectively perceived as unbalanced. This paper investigates the direct sound field's frequency response in the car and the effect of the early reflections upon the total sound field. In-car acoustics and subjective test methods are discussed as well.
A Wind-Tunnel Method for Evaluating the Aerodynamic Noise of Cars,"In this paper a test method for measuring the car aerodynamic noise in the Fiat wind tunnel is reported. Through this method measurements of vehicle interior noise in the test section generated by air flow are performed. The separation between interior aerodynamic noise and background noise (fan noise, self generated noise in the tunnel, etc.) is performed by simulation of the last one with loudspeakers without air flow. The present method allows also to separate the shape noise contribution from aspiration wind noise and to localize the most critical acoustical areas into the car. By means of this method it is possible to optimize the car shapes and seals in order to improve the vehicle acoustical comfort."
Automotive Convenience Products Trends and Prospects,"The purpose of this paper is to describe the growth and the trends of automotive convenience products. These products contributed to make the driving experience more pleasurable. Electronics have contributed to this growth since the sixties, and its contribution and prospects will be the prime focus of this paper. With the continuing advance of electronic products in the consumer and industrial sectors, the consumer wants' and expectations are changing, especially with the “Baby Boom” generation. More new convenience features will be developed by the prudent use of electronics. The development of these future products require a thorough understanding of consumer wants and needs through market research, careful adaptation of the emerging technology to avoid gimmickry, and dedicated application of engineering know how to design package efficient, cost effective and reliable products."
A New Dimension in Automotive Trim,"Colamco has developed new technologies which have many advantages for automotive soft interior trim applications. The process is particularly suited to molded seat production but has proven to be flexible enough for use on any interior surface. The process combines standard polyether urethane foam with fabric or vinyl and any desired backing material to achieve highly styled parts both in 3-dimensional shaping and embossed designs. Products may also exhibit further characteristics such as softness, multi-densities, full breath-ability, and high durability, as well as noise reduction and acoustical insulation. In the report we will discuss Colamco Technology, materials requirements, automotive seat molding, inherent differences between the Colamco technology and other processes, and special applications of the technology. Emphasis will be on automotive molded seating."
A Baseline Design for the Space Station Habitat,"A baseline design has been selected for the Space Station Habitat (HAB) element. The HAB provides the primary living space to support man's permanent presence in space. The HAB element is designed to provide an environment that maximizes safety and human productivity. This paper outlines some of the current design features including the common core elements and the man-systems hardware. The HAB is arranged in three areas based on crew activity and acoustical considerations. The first area is the quiet zone, which contains the crew quarters. The second area is a buffer zone for noise suppression, where the stowage, medical facilities, and personal hygiene facilities are located. The third area is the active zone which contains the galley/wardroom, laundry and exercise facilities. Each of these three areas will be discussed together with the applicable requirements, the common utility elements, and the man-systems hardware furnishings."
The Rolls-Royce Civil Engine Family - Today and into the Future,"Rolls-Royce Civil Engine strategy calls for technology development for derivative engine programs and application to longer term new propulsion concepts. In the near future, further development of the turbofan for the next generation of derivative aircraft is planned. Reductions in fuel consumption, noise, weight, and cost will be achieved with engine cycles in the range currently in service and by refinements to component efficiency and application of advanced materials and manufacturing techniques. This derivative approach is likely to continue until the relationship between first and operating cost changes dramatically. As fuel prices rise, or the demand for more rapid travel develops, changes to the basic engine cycle will be necessary. For long range, high subsonic speed operation, substantial increases in turbofan bypass ratio will be needed to realize further fuel burn reductions. For intermediate ranges the propfan may have limited application, but economics will probably dictate retention of a more conventional powerplant for short range aircraft."
Strength Problems of Low-Floor Urban Buses,"The main characteristics of up-to-date urban buses are the low floor level, high capacity, and the many large-size doors. The longitudinal bending load bearing elements of the frame structures of thin window and door supports, suitable for today's popular line design pattern, are the sidewalls and beams without door openings. The main torsional load bearing element, on the other hand, is the master beam made up of the longitudinal beams by means of the floor cover and the lattice joint of the latter's lower flanges. Since the structural height of the longitudinal beams playing the critical role in load bearing is governed, at a certain minimum free height provided for, by the height of the floor level, reduction of the latter will have to be associated with that of their dimensions as well"
Improved Laminated Windshield with Reduced Laceration Properties,"A new laminated automobile windshield called Triplex “Ten-Twenty,” fabricated from two thermally stressed glass plies of 2.3 mm soda-lime float glass laminated with a 0.76 mm HPR polyvinyl butyral interlayer, has been biomechanically evaluated by Triplex Safety Glass Co., Ltd., using a dropping headform and a skull impactor, and by Wayne State University, using a 50th percentile anthropomorphic dummy on the WHAM III sled test facility. The results of these evaluations at velocities up to 60 km/h are expressed in terms of Gadd index, head injury criterion, and various laceration scales including the new Triplex laceration index (TLI). Some details are also given of other properties of the windshield. The results of the evaluations indicate that the Ten-Twenty windshield offers a reduction of about two units on the TLI scale equivalent to one of the following: 1. A 99% reduction in the number of cuts when the length and depth of cuts remain unaltered. 2. A 90% reduction in the length of cuts when the number and depth of cuts remain unaltered. 3. A change in depth of cuts from one layer of skin simulation to another, but in particular a 78.5% reduction in the depth of cuts into the polyvinyl chloride base layer when the number and length of cuts remain unaltered. In practice, the length, number, and depth of cuts all change together so that one typical example taken from the test program of a two-unit reduction in TLI is: 1. A 62% reduction in the average depth of cuts into the polyvinyl chloride base. 2. A 27% reduction in the average length of cuts. 3. No increase in the total number of cuts. On the basis of these results, Ten-Twenty is a much safer laminated automobile windshield than those now commercially available due to decreased laceration to the occupants during a collision."
European Legislative Requirements for Agricultural Tractors and Farm Machinery,"This paper outlines the structure and interrelationships of the numerous European standards making organizations, with particular reference to agricultural machinery. Because many of the standards being developed by these organizations are becoming part of legislation in the various Common Market countries, their work is of great interest to the machinery manufacturers. Covered are the highway code-constructional requirements, safety constructional requirements, test codes, and engineering standards. The current status of requirements for lighting, tractor cabs (including structural tests, noise, and emissions), maximum speed limits, brakes, hitches, and safety in the various contries are discussed."
The Design of a Cost-Effective Quiet Diesel Truck,"This paper reports the results of a project whose aim was to develop a quiet truck in a cost-effective manner. In the paper a method of approach to identification of noise sources and diesel truck noise control is presented, along with a demonstration of noise control techniques and the results obtained. The final drive-by noise level, as measured by SAE J366a procedures, was 72 dB(A). The approach was to take a standard production truck and modify its exhaust system, fan, transmission, and cab enclosure. Although no modifications were made to the engine, a quieting kit consisting of dampening panels was fitted to it."
"The Environmental,Commercial and Regulatory Implications of SAE Recommended Practice J57a for Truck Tire Sound Levels","There can be no control over environmental pollution without methods for measuring how the environment is being affected by mankind. Consequently, when traffic noise was identified in 1964 by communities as an important form of pollution, it became necessary to measure the amounts of noise present and to assign relative importances to various sources in vehicular traffic. Truck tires were identified as being significant contributors and engineers from the tire and truck manufacturing industries acting under the auspices of the SAE set about to develop a test procedure that satisfied the immediate need - to initiate control over truck tire noise. This paper is a review of the outcome of that effort by one who participated in the earlier work on the testing standard. How well the method works, and how well it serves to meet the objectives now on the horizon are the preliminary topics of this discussion. The paper contains a discussion of the accumulated experience in testing tire noise and the current indications for a meaningful test procedure."
Photovoltaic Glazing for Automotive Applications,"A computer simulation of an automobile has been prepared which enables the spectral characteristics of the glass windows, semitransparent photovoltaic sunroofs, and special solar control coatings and films to be incorporated into the thermal analysis. This paper presents the resultant interior temperatures for three vehicle configurations when subjected to various ventilation flow rates, convection conditions, and solar control coatings."
A Comprehensive Programme for Hearing Conservation and Noise Control,"Emphasis is placed on noise control at source in the hearing conservation programmes in the U.K. factories of Lucas companies, especially when new plant is ordered. This paper briefly describes the overall plan and Company standards with five case studies to illustrate how they work in practice. It concludes with a summary of the key steps in the Company strategy."
A Unique Approach to Mobile CB,"A new 40-channel CB Radio System has been developed by a major automotive manufacturer as a regular production option for a number of its 1978 cars and trucks. To maximize theft resistance, the system uses a remote chassis, detachable microphone, and a tri-band antenna. The factory-installed CB features a uniquely styled power microphone, digital channel display, automatic scan, switchable noise blanker, memory for emergency channel 9, automatic noise limiter, and extensive vehicle noise suppression. Vehicle speaker(s) are time-shared with the entertainment system. This state-of-the-art system is presented here in terms of component functions, design development, manufacture, and test equipment and procedures."
Quiet Tires-An Overview,"Vehicle and tire manufacturers are currently working to produce quiet commercial vehicles and tires. While much time has been spent by both government and industry to gather data to cut vehicle noise, it seems that industry and government now wish to interpret this data and make use of it in a short period of time. But this cannot be done without consideration of cost. We must consider the initial investment of new tires, the labor involved and importantly the national availability of these products as replacements are needed. Only with the full cooperation of government, manufacturers, and the transportation industry can this be accomplished."
S-65-200 Commercial Compound Aircraft Design for Maintenance,"In the design of the S-65-200 Commercial Compound Aircraft - a 230 knot, 86 passenger transport - maximum consideration was given to meeting a high dispatch reliability goal and to ease of performing maintenance. This paper describes how maintenance and reliability of this compound helicopter is enhanced by use of new and improved technology. Use of built-in test equipment reduces electronic component maintenance by approximately 43%. An airborne integrated data system reduces line level maintenance by approximately 16% and provides trend information for detection of incipient malfunctions. A newly developed rotor head bifilar vibration absorber reduced aircraft vibration levels, thereby reducing airframe and structure maintenance by almost 15%. A modularized engine allows for minimum disassembly at intermediate levels of maintenance. New and high grade materials, such as composites and vacuum-melt steels, improve life characteristics of structure and dynamic components. The ability to inspect subsystems is increased, and all components are readily removable. Almost 95% of all maintenance actions are performed from outside the aircraft. The cumulative result of these features of the S-65-200 Commercial Compound Aircraft is a predicted 0.98 dispatch reliability. Direct maintenance is estimated at 9.3 maintenance manhours per flight hour for all levels of aircraft maintenance."
Development and Analysis of Door Side-Impact Reinforcements,"A door side-impact reinforcement beam has been developed that allows efficient use of material in resisting side crush loads. The beam section can be roll formed, thus permitting further economies in fabrication. Analytical techniques have been developed that evaluate and handle bending, buckling, and crippling in beam design. This paper covers the development that led up to these results and includes a detailed description of how to apply the analytical methods."
Importance of Acoustical Leaks in Passenger Car Bodies,"In its treatment of acoustical leaks in passenger car bodies, this paper considers the general principle of noise control in a passenger compartment, the concept of acoustical leaks, examples of such leaks, and design guidelines for acoustical isolation. The paper states that the basic problems can actually be designed into vehicles through lack of understanding of acoustical principle, and various examples are given in illustration. Remedies for some of these deficiences are also proposed. Finally, design principles formulated to eliminate acoustic leaks are presented."
System Engineering - A Window System,"Many of the formal system engineering procedures and techniques developed in the aerospace industry have convenient informal application to the analysis, evaluation, and qualification of new automotive design. This paper describes such “systemization” from a product engineering viewpoint in the development of a hardtop window project. The project is traced through its several design and development stages; and the advantages of the system engineering approach, as well as some of the problems encountered, are explored. The paper concludes with a discussion of additional controls that would have been required to yield the full information recording/retrieval capability demanded for complete system integration on larger projects. THE COMPLEXITY OF the present-day automobile is as evident in its door window systems as it is beneath the hood. Current usage of curved glass, repeatably positionable at superhighway speeds in a frameless or hardtop application, has posed new challenges for the designer. Additional emphasis on sealing capability, reduced operator effort, and low noise levels has compounded the design challenge. The designer has met these challenges by producing systems much more sophisticated than those in earlier cars. Optional hardware configurations that can be added or deleted from the system and partial modification of existing systems with during-model-run effectivity points are routine. Also, the cost of both materials and the labor associated with assembly, adjustment, and service are receiving additional emphasis today. All of these factors combine to make the product engineer's task in verification testing of window systems more difficult, and at the same time more important than it was previously."
Consumer Acceptance of the Volvo Passive Belt System,"Consumers' acceptance of and attitude toward a passive three-point belt system have been studied and evaluated in a personal interview investigation of 325 people. These participants were provided with the opportunity to try out the belt system in two demonstration cars-2-door and 4-door sedans. The method of selecting the respondents complied very well with the requirements of public representation. The results of the inquiry are presented in the full survey as related to driver, passenger, age, sex, etc. The main question in the study-the convenience when entering or leaving the demonstration car-was very positively judged. The most frequent opinion on a 7-point evaluation scale was as high as 7 (most positive); the average value of 6.2-5.9 was given for wide- and half-open doors, respectively."
An Update on Noise Control at International Harvester,"International Harvester has testified to the Environmental Protection Agency about present noise levels and has stated what it considers to be reasonable goals. Noise control work is progressing, especially in the area of environmental noise on lawn and garden equipment and operator noise on larger tractors. The engineering community must take every opportunity to present the case for cost-benefit considerations in noise control."
Comparison of Three Types of Front Body Construction of Sub-Compact Cars,"Three different types of front suspension and the corresponding body construction configurations were selected for comparison among unitary constructed sub-compact cars with a weight range between 2,500 lb and 3,000 lb and which are being manufactured by Toyota. These were compared and evaluated in terms of weight, productivity, noise and vibration characteristics, and crashworthiness. The pros and cons of each type were analyzed and the results of this analysis are presented in this paper. From these results, it has been concluded that when only the front body is considered, these three types of front body design are preferable in the following order. 1. McPherson type. 2. Double wishbone type with upper and lower arms installed on the fender apron. 3. Double wishbone type with upper and lower arms mounted on the suspension member."
180 Cu Yd Stripping Shovel,"Because of the size and weight of the various components going into the machine, new approaches were used to solve the practical limitations of manufacturing facilities, shipping clearances, and erection procedures. Although the general appearance of the machine is similar to previous units, there are a number of new design features incorporated in the unit. This paper will be limited to the major design considerations as follows: adaption to stripping two seams of coal simultaneously; dipper with two doors; computerized hydraulic steering maintaining Ackerman correction; double end drive crawlers and belt tensioning; and electrical innovations."
Noise Abatement of Vibratory Feeders,"Three principal noise-generating mechanisms were identified in the vibratory feeder as structural vibrations, interaction between the conveyed parts and the track surface and radiation from the bowl cavity. Treatment of the track surface based on theoretical analysis of the vibration-stimulated conveyance, structural damping treatment of the bowl and “see through, load through, reach through” acoustical screen have been developed. These treatments lead to 20–25 dBA reduction of the sound pressure level accompanied by substantial reduction of part delivery time."
"Past, Present and Future of Elastomeric Body Sealers in Automotive Application","Automotive body sealing has progressed from the time when the internal combustion engine replaced the horse on the buggy, which had no windshield, windows or doors, to the present time when every effort is made to make the passengers as comfortable as possible by isolating them from heat, cold, wind, water and noise. This pursuit of comfort has not only been made possible by but has also created the need for new developments in designs, materials, manufacturing procedures and tooling."
Metal Stamping Presses Noise Investigation and Abatement,Noise generating mechanisms connected with steel-blanking operation has been identified and their engineering treatments developed and tested. Use of rubber-metal laminates proved to be successful for cushioning impacts in kinematic pairs and joints. Use of plastic for the stripper plate construction was recommended. The “die stiffener” concept was developed to reduce main noise peak associated with punch breakthrough. Screening of the die cavity by a transparent curtain of overlapping PVC strips was shown to be effective. A pulse load simulator with adjustable load rate and amplitude has been developed to facilitate testing of presses.
"Optimum Subsonic, High–Angle–of–Attack Nacelles","Many proposed advanced aircraft - but especially tilt-nacelle, subsonic-cruise, V/STOL aircraft - require nacelles that operate over a wide range of aerodynamic conditions. The optimum design of such nacelles and their inlets is described, including how the inlet low-speed design conditions are selected, the conditions for which the various regions of the inlet are designed, and appropriate criteria of merit. For low-speed operation the optimum internal surface velocity distributions and skin friction distributions are described for three categories of inlets: those without boundary-layer control (BLC), those with BLC, and those with blow-in door slots and retractable slats. Experimental results are presented that show the performance of the various types of inlets. At cruise speed the effect of factors that reduce the nacelle external surface area and the local skin friction is illustrated. These factors are cruise Mach number, inlet throat size, fan-face Mach number, and nacelle contour. The interrelation of these cruise-speed factors with the design requirements for good low-speed performance is discussed. Finally an inlet design without BLC and an optimized inlet design with slots and slats are compared to illustrate the possible reductions in nacelle size."
"Energy Conservation Aircraft Noise, and the Bottom Line","The established distribution system is in the process of being restructured to combat the effects of high cost energy, inflation and environmental restrictions. As a part of this system, the air freight industry, also, must re-examine its options in equipment, energy reduction, financial risk and services offered. In the area of investment and energy reduction a cost effective solution is already available. That is, equip a portion of the existing cargo fleet with new technology, quiet, fuel efficient engines. Ten airlines have stepped up to this solution and are re-engining their fleets of DC8 aircraft with CFM56 engine."
A General Aviation Operator Views His Equipment,"Each new model change usually brings improvements over earlier models. From the point of view of increasing window area and designing more pleasing appointments, there have been significant advances. With regard to engine reliability and time between overhauls, significant advances have also been made. Solutions to some of the other problems, however, have made little gains. Examples are pilot sitting position and ease of seeing outside the cockpit area; noise level for effective verbal communications between instructor and student; and shoulder space for instructor and student in trainers. An area where major strides are yet to be made is in panel, cockpit, instrument, and control layout and function. A continuing concern expressed by pilots is the transition time from one aircraft to another or the problems of regularly operating in two or more aircraft. This suggests that there is a need to provide more commonality between airplane layouts. Since the hourly maintenance labor costs are increasing, the original design should consider labor-saving methods during routine inspections such as accessible location of battery. Performance data and aircraft systems descriptions should be more uniform between manufacturers."
"Airport Noise, Sonic Booms, and Public Health","Different adverse effects of noise are treated in the context of defining public health problems posed by exposure to sonic booms and to operational aircraft noise around airports. These aircraft sounds can affect states of social and mental well-being through masking speech communication or other desired sounds, disrupting behavior and subjective feelings, and interfering with needs for privacy, rest, and sleep. Such adverse effects fall short of what may be called mental disorders, but the long-term cumulative impact of these noise disturbances remains to be fully evaluated from the standpoint of mental as well as physical health. There may, however, be some potential risk of hearing loss caused by the maximum current aircraft noise exposures in neighborhoods bordering airports. Evidence for other physical ailments connected with exposures to aircraft sounds intruding in airport communities is suggestive at present and requires more medical verification. The most pressing research needs are for retrospective and prospective studies of the physical and mental health status of communities subjected to different amounts of aircraft noise and sonic booms."
Sound Attenuation After the Fact,"The noise levels of earthmoving equipment, in the operator's cab and outside the machine, are discussed. Ways and means of lowering the dB ratings for increased operator and by-stander comfort are taken into account. Suggestions are made for ways of mounting the cab itself and lessening vibratory reactions from the engine, including rubber engine and cab mounts, plus acoustical material for reducing inside the cab noise."
The Economic Necessity of Viable Door to Door Air Cargo Service,"Air freight is and will continue to be a small shipment business. The rapid increase in the amount of freight carried has induced a state approaching chaos on the ground. The result is delay, losses, and damage to shipments. The air cargo industry must now develop a sophisticated door to door capability offering improved service and lower costs to the user. Satellite air freight depots, with perhaps several airlines in a single building, must be developed in major commercial areas. Door to door container usage, at present faltering, should be encouraged. A new rating system, with door to door prices that taper with distance, should be devised."
A Passive Safety Belt System,"The geometry and behavior of several front-seat passive belt configurations have been studied and evaluated. General design criteria are discussed. The preferred solution is a three-point belt with two ends attached to the door. The belt straps automatically, and for comfortable exit, the occupant may make a slight manual operation. Crash tests indicate that the belt performs approximately as a standard three-point belt. Door strength, retractor strength, strap strength and tension, seat influence, etc., have been tested. Curves are given for recorded and computed data, including old and new severity index."
One-Wire Automotive Electrical Systems,"A single-wire vehicle electrical control system is applied to the various vehicle electrical functions. The resultant three-wire system (signal, power, ground) reduces wire bulk in the floor, door, instrument panel, and engine compartment of the vehicle. Increased control switch and component complexity, due to the additional solid-state components required, may affect overall reliability. Improved power bus and signal bus protection must be added to the control system. Failure of the entire single-wire control system, due to accidental grounds or opens, limits application to certain noncritical vehicle electrical systems."
Summerization of Construction Equipment,"This paper discusses some of the problems encountered in “summerizing” or air conditioning a cab used on construction equipment. The environmental conditions of high temperature and high relative humidity combined with severe dust shock and vibration conditions affect the design of components. Components discussed are compressors, condensers, evaporator coils, filters, air ducts, air diffusers and heaters. Installation for ease of maintenance and replacement is emphasized."
Evaluation of Aircraft Internal Noise,"From the standpoint of marketing as well as safety, control of aircraft interior noise is of considerable interest to the manufacturers of business aircraft. The interior acoustics engineer in the industry, having no fund of accumulated experience or research to draw from in the industry itself, has to piece together a working design procedure from a knowledge of boundary-layer theory, jet noise, random vibrations, and architectural acoustics to meet an acceptable cabin noise criterion for the small aircraft. In this paper, methods are outlined to calculate the cabin noise levels due to the three main noise sources-the boundary-layer pressure fluctuations, jet exhaust, and internal equipment. Formulas for quick estimation of overall noise levels due to these sources as well as methods to obtain octave band levels are given. The paper also discusses manufacture or service-related noises and methods for identifying their sources."
Window System Design Using Computer Analysis,"Soon after the styling door surface, glass drop, and belt height are determined, the placement of window system components is critical in effecting a smooth operating window system with low effort. For single arm - single post window systems, a computer analysis technique has been developed to position the post and regulator in the most optimum location. The computer program used displays results through the use of computer graphics. This graphic output allows instantaneous evaluation of how variations in geometry effect the window system operation."
A Consideration of Vehicle's Door Shutting Performance,"Many papers have mentioned, in passing, a phenomena that is known as “airtightness”, which is one factor that hinders automobile doors from closing. It also causes the eardrums of any passengers in the vehicle to be temporarily pressurized when the door is closed. However, few documents have considered this phenomena in detail. In this paper, we investigate the magnitude of “airtightness” as it affects ear pressure and examine its relationship to such factors as the volume of the passenger compartment, door's opening area and its inertial moment. Finally, we utilized estimation methods to predict its influence on the force required to close the door and the amount of the resultant air draft."
Development of Door Guard Beams Utilizing Ultra High Strength Steel,"Door guard beams have been developed through the utilization of ultra high strength steel (tensile strength>100 kg/mm2). At first, the sheet metal gauge was reduced in proportion to the strength of the ultra high strength without changing the shape of the beam section. This caused beam buckling and did not meet guard beam specifications. Analyzing this phenomena in accordance with the buckling theory of thin plates, a design criteria that makes effective use of the advantages of ultra high strength was developed. As a result, our newly designed small vehicle door guard beams are 20% lighter and 26% thinner than conventional ones. This makes it possible to reduce door thickness while increasing interior volume."
Vibration Analysis by Double Pulsed Laser Holography,"The use of a giant pulse laser with 30 ns double pulses makes it possible to holograph different phases of an object vibration within time intervalls from 100 μs to 1 ms onto the same plate. The vibration phases into which the first and second laser pulse are fired can be exactly preselected by means of an electronic trigger system. The simultaneous reconstruction of the holograms taken by the first and the second laser pulse generates on the object surface a system of interference fringes which are loci of equal displacement. Adjoining fringes correspond to displacement differences of half a wavelength of the laser's light. In this way, it is possible, for instance, to visualize the vibration pattern of car bodies and drive units excited by the running engine. The method of measurement and a hologram camera especially constructed for making double pulsed holograms of automobiles are described. Several examples of application are quoted in order to illustrate this technique."
Development of an Indoor Noise Test Procedure for Trucks,"An alternate, indoor, noise test procedure for truck exterior noise is being developed in order to overcome the weather problems associated with the presently employed outdoor test method. The feasibility of a reverberation room measurement of sound power level has been demonstrated through a series of comparative indoor and outdoor measurements for several vehicles. An indoor test procedure has been broadly defined and an experimental effort is continuing to complete its development and to demonstrate its equivalence to the outdoor passby test."
Aircraft Noise Control Practices Related to Ground Transport Vehicles,"Aircraft noise control practices which may have application to ground vehicles are presented. Noise sources, design criteria, prediction methods and test facilities are described. Recent application of aircraft noise control methods in the use of sound insulation, structural damping, air conditioning and engine noise are discussed. The overall technical approach (design process) to solving airplane noise problems is emphasized."
Materials for Noise Control,"The purpose of this paper is to present a basic overview of the technology and materials available for controlling airborne noise and structural vibration. The paper will be oriented to the truck industry. Materials and applications will be presented with this bias. The paper will cover technology of absorption, reflection and vibration damping. Material properties, availability and practical considerations to selection will be presented. Typical applications for materials in the truck market will be briefly highlighted."
An Example of Noise Control Treatment for Construction Machinery Cab Interiors,"The effect of noise on the operator has become of increasing concern to manufacturers of construction machinery in recent years. Although the noise generated by heavy duty construction equipment is much greater when compared to other types of machines such as the passenger car, the problems are similar. Many of the lessons learned in reducing interior noise within the automobile can be used to reduce noise within the operator's cab of construction machinery. This paper represents the results of a joint effort between Fiat-Allis Construction Machinery, Inc., and Globe Industries, Inc. to apply these lessons to reduce the noise within the cab of a medium sized crawler tractor."
Durability of Rubber Modified SMC,"A carboxylated butadiene-styrene elastomer has been developed as a low profile modifier for polyester resins used in sheet molding compounds. The elastomeric modifier will provide Class A surfaces with low long-term wavi-ness, energy absorbing characteristics and zero shrinkage. Especially outstanding results are obtained when molding large, thin, flat panels such as roof, door, hood and tailgate panels from rubber modified SMC. Surface appearance properties are subjective, but properties such as radial bend, tension testing, high impact and reverse impact tests are shown to demonstrate the energy absorbing and toughening characteristics imparted by the modifier."
A Bus for Denver’s Mall,"A unique shuttle bus is being constructed by Minicars, Inc., and Walter Vetter Karosserie-werk for Denver’s Transitway/Mall. The bus is designed for frequent stop, low speed service in a downtown pedestrian environment. It features a very low floor and multiple wide doors for rapid passenger boarding and deboarding. Two versions will be supplied for comparative evalation, a low noise diesel configuration and a battery-electric configuration. Either version can subsequently be converted to the alternative propulsion system."
State-of-the-Art-Ergonomics and Motor Vehicle Safety,"The use of ergonomics in the design of vehicular equipment is presented. It is proposed that the wider use of the principles and methods of this discipline might aid in the more effective integration of the driver and his equipment. It has been shown that the effectiveness of any man-machine system depends upon the integration of the biological characteristics of the operator with the mechanical design of the equipment and working areas. The initial phase of a program in ergonomics should always consist of an advance analysis of the equipment, including a survey of the nature of the task, the work surroundings, the location of controls and instruments, and the way the operator performs his duties. In highway safety the application of human engineering principles has been shown to be of great importance in the design of windshields, rear view mirrors, and vehicle lighting, and other visual aids to the drivers. The field of crash injury research is proving to be especially important in understanding the parts of the vehicle most likely to give rise to injury. Current research is tending to give more precise measurements not only in regard to the forces involved, but also to the thresholds and patterns of injury. The various research programs in the field of ergonomics as related to highway safety in various parts of the world have greatly increased in recent years."
Reducing Construction Equipment Cooling System Noise to Meet the French Noise Requirement,"A major noise source on construction equipment is the cooling system when tested according to the French Noise Test Procedure. This paper describes the procedure and methods used to reduce economically the Case 580B CK loader-backhoe cooling system noise to 75 dB(A), well below the French limit of 80 dB(A) for the whole vehicle, and remain within the desired physical and performance constraints. This was accomplished primarily by reducing fan speed and using a larger capacity radiator to maintain adequate cooling."
Experimental Studies of the Space Shuttle Payload Acoustic Environment,Two series of experiments were conducted to reduce the uncertainties concerning the Space Shuttle payload bay acoustic environment. Tests using a one-fifth scale model showed large changes in level below 125 Hz with the introduction of typical payloads. The changes were associated with particular acoustic modal behavior and were sensitive to the type of acoustic excitation. Another series of experiments evaluated the noise reduction of the first orbiter vehicle (OV-101). The results showed consistently greater noise reduction for grazing excitation than for diffuse excitation. The results were extrapolated to OV-102 using mass law relations and acceleration measurements.
Light Vehicle Frontal Impact Protection,"This paper addresses the protection of occupants in light vehicles. It presents data and techniques for identifying and measuring potential crashworthiness improvements that would mitigate injuries to occupants striking frontal interior components such as the steering wheel, instrument panel and windshield. Both restrained and unrestrained occupants can be injured by frontal interior components in crashes. The focus of this paper is on the unrestrained occupant. However, performance criteria and associated countermeasures will have to be developed considering the differences in the mechanisms of injury to both the restrained and unrestrained occupants. Work on the restrained occupant and the similarities and differences between both conditions remains to be considered. The paper presents information on the magnitude and types of injuries received from frontal interior components and on how the performance of these components and the vehicle structure affect the resultant injuries."
GMC Fiberglass Truck Door,A new fiberglass door was designed to replace steel doors on GMC heavy duty trucks as a quality improvement while reducing cost and weight. A feasibility study led to the selection of SMC for the door material. The new design incorporated unique design features and innovative materials applications. Finite element analysis was used to determine optimum material distribution for reducing stress and weight and for increasing stiffness. A test program was conducted which verified the design criteria and objectives were met.
A Subjective Assessment of Truck Ride Quality,"A subjective assessment of ride quality was undertaken in order to estimate the relationships among 22 factors that affect concepts of ride quality and to assess the interaction of these factors with 7 ride quality issues. Nine line-haul drivers drove and rated each of 16 tractor-trailer vehicles. The factors, driver vibration, ease of steering, and interior cab noise determined overall impressions of ride quality. Of the issues, front axle load, tractor configuration, tractor rear suspension, trailer suspension, trailer load, wheel base length, and newer and older cab designs, the latter evoked the clearest differentiation of ride quality between paired vehicles."
Reduction of Traffic Noise Impacts Via Path Controls,"Path control measures to reduce traffic noise impacts include roadway alignment, site planning, noise barriers, and building insulation. Roadway alignment and site planning are most effective when included during the project planning stages. For existing noise problems, roadside noise barriers are effective, providing reductions of up to 15 dB(A). Some sites require building insulation to reduce traffic noise impacts. Three levels of modifications are considered: (1) sealing leaks, (2) modification of small structure elements, and (3) wall panel modifications."
Side Impact Modelling Using Lumped Mass and CAL-3D CVS Simulations,"Experimental research to improve protection levels offered to automobile occupants in lateral collisions has focused on the study of responses of the 50th percentile male as a result of the availability of the Side Impact Dummy of that size. The question of the suitability of protective measures developed for the 50th percentile male for the other occupant sizes is of concern. Hence, a major objective of this study was to analytically evaluate injury potential of a broad range of occupant sizes in lateral collisions in combination with various types of padding. Two computer models were used in the study. The first was a one-dimensional lumped mass model. The CAL-3D crash victim simulation was also configured to represent an occupant in a lateral collision with intruding door motion. Results of the study indicate that padding on the interior of the door surface is beneficial to all occupant sizes."
Interior Noise Reduction in a Recreational Van,"A study was made to determine the effect of combinations of acoustic treatments on the interior noise levels in a 3/4 ton van. The effect of barriers, absorbers and vibration dampers in various combinations on the dBA levels are given for both idle and highway operating conditions. A noise reduction of up to 10 dBA was obtained for certain barrier and absorber combinations."
APPLICATION OF THE FINITE ELEMENT METHOD TO THE DOOR INTRUSION AND ROOF CRUSH ANALYSIS OF A PASSENGER CAR,"In order to satisfy the various international safety standards which currently exist, it is necessary that nearly all new vehicles be subject to a number of destructive tests before being made available to the public on the open market. Development programmes involving a series of such tests are very expensive and there is a growing need that reliable and economical design/analysis methods be made available. This paper attempts to present such a method. Using a relatively simple finite element computer program which has been adapted to the particular needs of the motor industry, the analysis of a new prestige limousine is described. A background to the analytical method is presented, but the emphasis of the paper is on the engineering aspects of using the method. Reference is made to practical design considerations in several instances. The results of calculations predicting the performance of the structure when subject to FMVSS 214 and 216 are presented."
External Surface Noise Radiation Characteristics of Truck Diesel Engines - Their Far-Field Signatures and Factors Controlling Abatement,"The engine is an important source of diesel powered vehicle noise, and becomes dominant after proper treatment of exhaust and cooling system noise at vehicle speeds below fifty miles per hour. This paper presents the results of a comprehensive study dealing with surface noise radiation characteristics and the ranking of sources on three truck diesel engines. A special acoustic facility constructed to emphasize the acquisition of diesel engine noise data is describad. Information is presented on measurement methodology and its viability for quantification of engine noise, directivity, and radiation patterns from engine surfaces. Acoustic measurements, conducted over a range of engine loads and speeds, include spectral analysis of the sound pressure field derived from a thirtytwo microphone spherical array. Various noise identification techniques are explored under comparative testing to ascertain potential candidates for quantification and ranking of engine external surface radiation. For the engines studied, the sound power output varies, depending on design; the loudest being the naturally aspirated; and the quietest being of prechamber design. This range varies between 8 and 10 dB (A) at maximum throttle and is speed dependent. Turbocharged engines exhibit a marked change in sound power output under increased load conditions. This is most pronounced at lower engine speeds. The sound pressure field of two in-line turbocharged four-stroke diesel engines contained a high degree of asymmetry whereas the sound pressure field of a two stroke vee configuration engine appeared representative of a finite monopole acoustic radiating source. Major external engine surface acoustic radiators, common to all engines tested, included engine front, block sides, and valve covers. Other major external sources were after-coolers and exhaust manifolds for specific engine designs. Oil pan noise, although a lesser contributor to overall engine noise, depends on factors which include the design, material and construction. Finally, comparisons are made of noise data acquired for the acoustic facility and data acquired for the same engine installed in a typical highway truck chassis located out of doors."
Noise Reduction of a U.S. Army 5-Ton Truck,"Research is demonstrating that it is possible to significantly reduce the in-cab noise levels of the Army's current truck fleet, with accompanying exterior noise reduction. Results are applicable to future Army trucks as well and are reported on a program utilizing a 5-Ton Army Truck. This type of truck was found generally to exceed the applicable limits established in the new MIL-STD 1474, “Noise Limits for Army Material.” The program identified major noise sources and important paths for sound to enter the cab and resulted in the selection of optimum sound absorption, sound barrier and vibration damping materials. The effect of a prototype exhaust system and its placement relative to the cab and the importance and optional means of controlling cooling fan and engine noise were also investigated."
The Evolution of Sound Testing at Kohler Co.,"The purpose of this paper is to discuss the development of Kohler Company's Small-Engine Noise Test Program. Particular emphasis will be placed on noise instrumentation and analysis techniques. The paper will not dwell on the specifics of each noise study technique, but will be an overview, describing the evolution of Kohler's Noise Test Program in general."
Development of Lightweight Door Intrusion Beams Utilizing an Ultra High Strength Steel,"Door intrusion beams have been fabricated from an ultra high strength steel resulting in an efficient side impact protection system. Despite the ultra high strength (yield strength∼150 ksi) the steel may be roll formed into beams from thin gauge material (0.035 in) resulting in significant vehicle weight savings while still meeting all federal specifications. This paper covers the development of this door intrusion beam system and includes detailed descriptions of beam design, beam testing and steel properties."
Hailstone Response of Body Panels - Real and Simulated,"The dent resistance of aluminum and steel autobody panels has been studied under controlled laboratory conditions and by field observations and measurements of actual hailstone damage. Analysis of the results shows that very nearly the same response occurred in the lighter weight aluminum components as occurred in the steel panels. The autobody components were all 1977 model year production panels. Laboratory testing included four steel and four aluminum hoods, both painted and unpainted. The hailstone damaged components included a steel hood, aluminum doors and an aluminum fender. The aluminum and steel panels were damaged in the same hailstorm during May 1977. The analysis of denting resistance presented in this paper is based on insight and experience gained from a four-year cooperative program of Reynolds Research and several automobile companies. The results given here supplement previously published laboratory data and confirm the conclusion that lighter weight aluminum autobody panels can be designed to give at least comparable, if not better, dent resistance than conventionally used steel panels, and at a weight savings of 50 percent."
New Designs Through Vibration Welding,"A new plastics assembly technique has been developed which offers new opportunities in product design and assembly as well as new solutions to existing problems. This method, based on friction welding, overcomes many limitations of conventional welding processes such as part size, shape, material and speed of operation. It produced strong, pressure tight joints."
Evaluation of Cooling System Design for a Portable Air Compressor Designed to Meet EPA Noise Requirements,"A cooling system design for a gasoline engine powered portable air compressor designed to meet EPA noise standards is evaluated. This paper covers the development that took place in order to devise an adequate cooling system for a silenced compressor with noise reduced by shrouding of the machine with a sound attenuating housing. The successful cooling system consisted of resolving maximum engine coolant temperature and maximum compressor discharge temperature while maintaining a compressor noise level of 76 dBA at 7 m. The cooling system design procedure involved is outlined. Noise evaluation at Sullair Corporation, and cooling system testing at McCord Corporation are reported."
Highlights of UMTA's Rail Program,"This paper highlights the role rail research programs of the Urban Mass Transportation Administration (UMTA). Included are descriptions of several recently developed commuter transit cars-the state-of-the-Art Car, The Advanced Concept Train and dual-powered, gas turbine/electric cars. Also discussed are efforts by UMTA in developing test facilities for urban rail vehieles and in furthering research in tunneling technology and noise abatement."
Designing Body Panels for Corrosion Prevention,"To aid in avoiding the corrosive elements of the environment, the designer of sheet metal body panels should consider principles which provide optimal drainage and access for the application of protective coatings. Major vehicle body components are considered individually or in closely related pairs such as door inner and outer panels. The general guidelines for preferred construction of drain holes, shingling, shielding and access for material application are outlined for each major component."
A Method for Assessing Turbine Engine Run-Up Noise Impact on Airport Neighbors,"A methodology for assessing ground run-up noise exposure/impact resulting from turbine engine performance testing on outdoor facilities was developed. The overall methodology consists of three calculation procedures using dBA levels (measured or estimated) to predict the Day-Night Level (LDN) at any location across existing terrain. The methodology provides the analysis capability required to 1) study noise suppressor requirements in order to minimize costs, 2) locate run-up and test-cell pads, and 3) study the impact of run-up operations changes. It also provides a potential capability for assessing noise exposure from 1) takeoff power check run-ups, or 2) other (non-turbine) static noise sources."
Experimental Approach to Reduction Technique for Engine Noise in Passenger Compartment,"This paper deals with high frequency noise in the passenger compartment which are caused by transmitted engine noise. For the purpose of noise reduction, several evaluation methods are developed. For the evaluation of a body transmission loss, a combination of a reverberant room and an anechoic room is used. The noise absorption of the compartment is evaluated under the concept of the saturated sound pressure level. And sufficient standard samples are measured to support the noise reduction development."
Noise Control on a Heavy-Duty Mobile Crane,The intent of this paper is to illustrate how simple testing techniques and application of elementary noise concepts helped attenuate the noise in the operator cabs of a heavy-duty mobile crane to within the 8 hour/90 dBA limit established by the Occupational Health and Safety Act of 1970.
"A Modern Technology, Open-Ocean Seaplane Design","Modern technology has been applied to derivation of a viable open-ocean seaplane design capable of operation from, and sea sitting in, sea state 5. Beginning with a delineation of traditional seaplane limitations and philosophically unencumbered by orthodoxy, the design features a blended catamaran-fuselage hull, hydrofoil, high wing, twin boom, and Vee tail with top-mounted engines. Weighing 1.25 million pounds including weapons and avionics suite, the design has been applied to a Sea Control mission. Consideration has been given to concepts for inhibition of motion sickness."
Flight Displays for the Next Generation Aircraft,"The influence of the increasing complexity of the commercial transport operating environment is cited as the reason for applying advanced display technology to new aircraft design. Principal factors are the fuel crisis, sensitivity of the environmental noise, and the need for increased traffic capacity. Industry-wide development programs for fully configured flight decks, as well as specific subsystems, are reviewed."
Reduction of JT8D Powered Aircraft Noise By Engine Refanning,The purpose of the Refan Program is to establish the technical feasibility of substantially reducing the noise levels of existing JT8D powered aircraft. This would be accomplished by retrofitting the existing fleet with quieter refan engines and new acoustically treated nacelles. No major technical problems exist that preclude the development and installation of refanned engines on aircraft currently powered by the JT8D engine. The refan concept is technically feasible and provides calculated noise reductions of from 7 to 8 EPNdB for the B727-200 aircraft and from 10 to 12 EPNdB for the DC-9-32 aircraft at the FAR Part 36 measuring stations. These noise levels are lower than both the FAR Part 36 noise standards and the noise levels of the wide-body DC-10-10. Corresponding reductions in the 90 EPNdB footprint area are estimated to vary from about 70% for the DC-9 to about 80% for the B727. The refanned aircraft should perform typical range/payload missions with a negligible effect on block fuel. Production retrofit kits could be available in 1976 for the DC-9 at a unit cost of about $1.0 million and in 1977 for the B727 at a unit cost of $1.7 million.
A Noise Control Study of Certain Diesel-Powered Strip Mine Vehicles,"This paper describes the work performed in three distinct noise studies on typical diesel-powered strip mining equipment and discusses their results. Mufflers lowered diesel exhaust noise exposure for adjacent workers and the community at large, but had little effect on the noise level at the operator's position. Properly designed and installed noise control kits can be an effective method of reducing the operator's exposure to an acceptable level, and can simultaneously dampen vibration inside the cab."
An Investigation of the Noise and Overpressure Generated by the Safety Air Cushion,"The results of an experimental study of air cushion noise and overpressure are presented, and methods to reduce these effects are investigated. Free-field studies of inflator noise are made in an open anechoic room, and various silencing devices are tested. Studies are also made of the combined inflator noise and overpressure in a closed passenger compartment. Tests are made for different window openings in the compartment. Results are presented for a new experimental air cushion that draws in air from the passenger compartment as it inflates. Some of the implications of the data with regard to risk criteria for damage to human hearing are discussed."
Experimental and Theoretical Study of the Rolling Noise in a Passenger Car,"This paper presents an analysis of low frequency noise production by experimental measurements and mathematical model calculations. It shows vibration coupling between train, body and cavity modes and it points out different possibilities to reduce noise in the passenger compartment."
A Method of Sound-Field Simulation for Automobile Passenger Compartments,"By estimating the sound field characteristics of an automotive cabin at a period prior to the actual manufacture of a car using available information on interior size, shape and acoustic materials, it is possible to realize a car audio system of high quality through appropriate placement of loundspeakers and determination of best electrical compensation networks, among others. We have established a computer-aided method based on the sound ray-tracing method and digital signal processing techniques usually applied to the analysis of large concert hall acoustics, which simulates the transmission characteristics between a loundspeaker and a listening position."
Advances in Vibration Welding Technology,"The primary objective of this paper will be to focus attention on recent major advances in vibration welding technology which directly apply to the automotive industry. Breakthroughs in large part welding capabilities, combined with product improvements, now extend the range of current joining possibilities, opening the way for new and innovative automotive product design. Welding reinforcements up to 50” (127cm) long, to an all plastic bumper, has become a reality with the development of a large part vibration welder (LPVW). Currently in production, this new technology and equipment can also be applied to other large part applications, such as welding structural or support members onto large exterior components, i.e.: hood and trunk lids, quarter panels, valence panels and spoilers. Improvements in standard sized welders such as advanced process controls and built-in flexibility will offer significant gains in weld quality, automation, adaptation and overall productivity. A discussion of basic theory and principles of operation will be essential for background Information, along with equipment descriptions ranging from standard welders to special large part vibration welders. Details such as part size capabilities, operating parameters, and equipment selection relative to specific types of applications will be described thoroughly. Examples of successful assembly applications in areas such as fuel management, exterior lighting, ducts, and under-the-hood components will be used for capability familiarization."
Dolby Noise Reduction in Automotive Applications,"In the past decade, the high frequency response of automotive tape playback equipment has been extended, the efficiency of loudspeakers has increased and the cost of high power amplifiers has been reduced. Consequently, tape noise can be a significant problem when listening in the car. This paper discusses the design philosophy of the Dolby B-type and C-type noise reduction systems that are now widely used throughout the in-car entertainment industry to overcome the tape noise problem. Information relating to basic tape parameters, to other approaches to noise reduction and to noise reduction system defects is also included."
Recent Development of Plastic Material for Automotive Interior Application,"In addition to weight reduction and cost reduction, maintenance of the initial quality has become an important subject including color matching after long years of use since automobiles are used for longer years these days. This paper decsribes an outline of our manufacturing process of instrument panel pads, characteristics of the new surface material which we developed for above requirements, quality comparison of the surface material with those by other methods, possibility of applying this new method to other interior parts, for example, door trim, and so on."
Noise and Vibration Reduction Measures Applied to Diesel Engine Cars,"Some instances of the corrective activities concerning the noise and vibration problems such as idle noise, idle shake, driveline rattle, intake noise and booming noise experienced in the development stage of new diesel engine passenger cars are introduced here."
Application of Acoustic Modeling Methods for Vehicle Boom Analysis,"This paper describes a system modeling technique for predicting passenger compartment “boom” for a specific car design prior to the building of a prototype vehicle. Since “boom” — defined here as auditory response in the 20 Hz to 80 Hz frequency range — is dependent on body panel vibrations as well as air acoustic properties, three-dimensional finite element models of both body and air are constructed. These models are incorporated in existing vehicle models which include powertrain and chassis representations of the type previously used for performing shake and harshness analyses. To avoid non-symmetric mass and stiffness matrices, a modal method using auxilliary variables is utilized to couple the acoustic and body models. Included in the paper are discussions of modeling issues unique to structural acoustic simulation as well as several examples of studies in which sound pressure level response to realistic inputs is predicted and reduced by simulated design modifications. Test results are presented for comparison. Finally, graphical presentation of panel acoustic contributions is shown to be a useful tool in selecting possible body structure design changes for “boom” improvement."
A Review of Glazing Road Use Conditions and Laboratory Simulations,"This paper addresses glazing road use conditions and presents the results of a research program which investigated laboratory simulations of road use A review of current testing requirements for glazing used in locations through which driver vision is required is presented to introduce the development of improved glazing performance factors. The focus of this paper is the perceived need to insure the continuing use of realistic safety performance tests as new glazing technology emerges. This paper presents results of test simulations on glass, plastic, and glass-plastic materials using elements of a road use exposure model. Both sequential and non-sequential types of testing were evaluated."
Application of Finite Element Methods to Vehicle Interior Acoustic Design,"This paper describes the capabilities of the finite element method for vehicle interior acoustic analysis. Structural and acoustic finite element models of a van-type vehicle are employed to illustrate the implementation of the method in the design stage. Included as representative examples are studies of the acoustic resonances and forced acoustic response of the compartment cavity, which provide preliminary guidelines for initial compartment acoustic design. At a later stage, when the vehicle structural model has been developed, the finite element models of the structure and the passenger compartment cavity can be coupled for a total vehicle system evaluation. The paper illustrates the accuracy of the coupled model by comparison with the measured response in the van. Finally, the systematic application of this finite element methodology in a computer-aided procedure for the acoustic design of the passenger compartment is discussed."
Analysis Systems for Acoustic Intensity Noise Measurements,"The sound intensity calculation techniques have been implemented on a variety of instruments, but an integrated system application of the intensity technique offers more functional freedom and expandable processing options. This paper deals with a brief background of the system implementation of sound intensity methodology and its general application."
Development of Sound Localization Control System for Car Stereo,"In a two-loudspeaker stereophonic reproduction system of a passenger car, the geometrical configuration of the right and left loudspeakers has the disadvantage of being asymmetrical to the listener. For this system, we have made both theoretical and experimental verifications of the effects of strongly reflected sounds on the sound pressure level difference and phase difference between two ears which determine the location of sound image in a small compartment of a passenger car. On the basis of these verifications, we have developed a new sound localization control system. With this system, acoustical effects such as sound expansion and ambience have been greatly improved in a passenger car. In this system, input signals to the loudspeakers are controlled so that the sound image produced by the loudspeaker nearer to the listeners may acoustically move so as to position itself symmetrically with the other loudspeaker with regard to the listeners. The corner-mounted loudspeaker and the sound localization control circuit constitute the distinctive features of this system. The corner-mounted loudspeaker suppresses strongly reflected sounds, which are characteristic of the sound fields in a passenger car, and improves the definiteness of acoustical sound localization. The corner-mounted loudspeakers are installed toward the corners of the intersections of the instrument-panel near the right and left doors so that the directivity axis of loudspeakers makes an equal angle of 45 degrees with the two vertical planes passing through the instrument-panel and each door. The sound localization control circuit consists of an inverter, a pre-amplifier and a delay circuit unit. This control circuit is connected to the power amplifier output stage of a conventional audio components. With this circuitry, acoustical effects such as sound expansion and ambience are greatly improved."
Aerodynamic Characteristics of the Fiat UNO Car,"The purpose of this article is to describe the work conduced in aerodynamic field throughout the 4-year development and engineering time span required by the project of the UNO car. A description is given of all the parametric studies carried out. Through these studies two types of cars at present in production were defined and the characteristics of a possible future sports version laid down. A movable device, to be fitted in the back window, was also set up and patented. When actuated it reduces soiling of back window. A description is also provided of the measurements made in the car flow field and some considerations are outlined about the method applied. This method is still in development phase but it already permits some considerations and in-depth investigations to be made on the vehicle wake."
The National Highway Traffic Safety Administration's Evaluations of Federal Motor Vehicle Safety Standards,"A history of the evaluation of existing motor vehicle safety devices by the National Highway Traffic Safety Administration and other researchers. The discussion emphasizes observations of researchers toward the safety standards and the extent to which these have influenced or were influenced by evaluations. Issues concerning energy absorbing steering columns, head restraints, side door beams and windshield glazing and bonding are covered in detail. This paper presents the views of the author and not necessarily those of the National Highway Traffic Safety Administration (NHTSA)."
System Electromagnetic Compatibility Through Component Testing - An Overview,"By nature, automotive electronic systems are susceptible to Electromagnetic Interference (EMI). Devices capable of suppressing EMI have become an integral part of the automotive electronic system design. Methods of testing these devices individually and as part of the total electronic system have been developed and used as a design tool by the engineer. These methods range from individual component tests to total electronic system analysis and cover such areas as radiated noise susceptibility and the effects of electrical transients on the electronic system. The ability to test components in the laboratory allows the engineer to assemble reliable subsystems from which a total electronic system may be designed. Components and subsystems may be tested using a TEM cell, anechoic chamber and/or direct injection of noise signals. Computer control of the test provides repeatable results and better turn-around time than can be obtained by manual testing. This paper will present different methods of performing Electromagnetic Compatibility testing on components and electrical subsystems. Procedures for characterizing susceptibility to EMI will be reviewed and its applicability to the design process will be discussed. Case histories will be included to illustrate the advantages of component and subsystem testing to total vehicle analysis."
Application of Acoustic Intensity Measurement to High Frequency Interior Noise,"This paper describes the application of an acoustic intensity measurement method to high-frequency interior noise. Technical problems in applying an averaging technique via surface scanning to high-frequency interior noise were conquered, and detailed quantitative contribution analysis of interior surfaces was made possible. Based on the analysis of a small passenger car, the effectiveness of additional noise control treatment can be roughly estimated, and an acoustic confort of the car was improved by a minimum additional treatment required."
Aeroacoustic Flight Test of Four Single Engine Propellers,"A flight test program has been conat the Aeronautical and Astronautical Research Laboratory (AARL) of The Ohio State University to measure performance and acoustic characteristics of four propellers designed for use on single-engine general-aviation airplanes. Three of the propellers were designed to reduce acoustic noise, while the fourth was a standard production propeller used for comparison. The tests show that notacible reduction in near-field noise was achieved at a constant propeller rpm, and that comparable aircraft performance may still be maintained."
Application Of The Finite Element Method To The Design Of The Front Door Of A Light Commercial Vehicle,"The paper describes the development and application of a relatively fine mesh model, analysed using MSC NASTRAN, to predict absolute values of deflections which correlated closely to the mean measured deflections of the actual door. The model has proved valuable in identifying and correcting at the pre-production stage the problem of the front door fit conditions. The paper then discusses the application of the model for structural analysis using strain energy techniques. The resulting design gives 21% reduction in deflection and stress at critical points with only 3% increase in mass. This contributed to significant savings in proto-type testing and in addition, provided more efficient use of the material in the structure."
Development of Multiplex Wiring System with Optical Data Link for Automobiles,"This paper contains an explanation of a Multiplex Wiring System with Optical Data-Link for cars, which has been installed in the Toyota “Century” since 1982. In this system, a total of 64 signals related to door wiring are transmitted in a multiplex fashion, and the number of wires from the front right-hand door to the interior could be reduced from 46 wires, which were used with conventional wiring techniques, to 10 wires including 2 plastic optical fibers. This system also has various control functions which includes a door-lock control function. In order to give high reliability to this system, we have developed a new optical data-link as well as a new custom micro-computer. And in the automobile industry, such a large scale multiplex wiring system having high reliability is very innovative in our opinion and will surely have a large impact in the future."
Maxi-Mini Car,This paper investigates an alternate design for a small car with maximum interior space. The most advantageous design was found to be a three seater vehicle with a possible fourth seat. The driver is positioned in the center of the vehicle. All seats are movable front and aft and sideways and the trunk is variable giving maximum space utilization and versatility. The car has unique folding doors which swing up far into the roof for easy accessability to all seats. Space for 3 or 4 people is provided in a vehicle of less overall dimensions than current designs. Through use of plastic materials weight is also lower guaranteeing excellent fuel economy.
The Ejection Reduction Possibilities of Glass-Plastic Glazing,"Ejection is a major problem in motor vehicle safety, with some 43,000 people per year being ejected from passenger cars, with some 6000 of these killed. About half of these people killed are ejected through glazing areas. The November, 1983, amendment of Federal Motor Vehicle Safety Standard 205 now allows the use of glass-plastic glazing anywhere in a motor vehicle. Our study has explored the “safety net” implications of glass-plastic glazing, produced by Saint-Gobain Vitrage, 3M, and DuPont for the anti-laceration implications but tested in our study for reducing ejections by controlled deformation after the glass layer or layers break. The inner plastic layers holds the broken pieces of a tempered side glazing together enough to reduce adult head partial ejection in side impacts, with the plastic layer trimmed to the glazing edges. By extending the plastic layer and securing it to the window channels, a 44 pound child moving at 20 mph toward the window may be stopped without ejection, with severe but possibly tolerable neck loads. Plastic layers which allow a greater deformation without failure appear desirable, to give glass-plastic glazing both a reduced laceration and a designed reduced ejection capability. This paper presents the views of the authors and not necessarily those of the National Highway Traffic Safety Administration (NHTSA)."
The Performance of Automobile Glazing in Urban Accidents,"Laminated glass windshields have not yet been demonstrated to be safer than a less expensive, single sheet of tempered glass. Data from injury-producing urban traffic accidents in Australia, involving tempered glass windshields, reveal that while the windshield is a major cause of injuries, they were generally slight and rarely disfiguring. By modifying the method of mounting the tempered windshield and by controlling the particle count near the periphery of the windshield, the risk of laceration may be greatly reduced."
Correlation Between Windshield Head Injuries and Laboratory Tests Part I: Feasibility of Relating Headform Impacts to Clinical Head Injuries,"By duplication of glass fracture patterns, the feasibility of relating 22 lb headform impacts to head injuries sustained by occupants contacting the windshield in crashed vehicles has been established. For each suitable windshield sample selected from available 1966 to 1969 crashed automobiles, a vehicle analysis was performed. The unbroken sections of 33 selected windshields were subjected to dynamic loads using the 22 lb portable headform. This portable device mounted in a van is described. At impact, the deceleration and velocity were measured and lacerations rated on the basis of damage to simulated tissue and moist chamois. Achievement of duplication between headform and occupant head impacts permits a numerical assessment of windshield lacerative injuries and presents a tentative method for future programs involving correlation between laboratory and service performance."
Side Impact Structures,"New side safety structural changes have been developed for some 1969 model General Motors cars. The research covered two years, during which time crash situations were simulated and analyzed, field data were studied, and various approaches to side protection were investigated. A low-weight, high-strength steel beam was developed and positioned horizontally in the door. In addition, the supporting body structures were reinforced. The resultant structure reduced penetration into the passenger compartment during side collision tests by causing a deflecting action between the two cars, and by preventing ride-over of the striking vehicle into the struck car. Fisher Body has recently developed the basis for a static laboratory technique of testing that measures the strength of side impact structure in such a way as to allow tryouts of designs early in the program. Because of the number of GM cars designed each year, this will curtail the extensive time and cost factors previously involved in dynamic testing."
Elastic Vibration Analysis of Passenger Car Bodies (Bending and Torsion),"This paper presents the outline of a theoretical analysis of bending and torsional vibration of passenger car bodies. Body structure is simulated by a framework with tension rigs and additional panel stiffnesses. The framework is a three-dimensional model for the bending and torsional vibration, or two-dimensional for the bending vibration, and is analyzed by the lumped mass system. All input data are calculated from drawings, and therefore characteristics of body structure are forecast and controlled in the design process. The analysis is also applicable to coupled vibration and forced vibration problems."
Perforation Corrosion at Lapped and Cold Formed Portions in Cold Rolled and Galvanized Sheet Steels,"In order to prevent corrosive parts such as hood, trunklid, door and side sill in an automotive body from corrosion, a new perforation corrosion test to simulate the corrosion at lapped and cold formed portions was conducted on cold rolled, galvanized, and zinc rich primer coated steels. Anti-perforation of galvanized steels with zinc of 95 or 128 g/m2 and galvannealed steel with zinc-iron of 59 g/m2 is remarkably improved compared to cold rolled DDQ mild steel so that they decrease the reduction in thickness to about 1/2 or 1/3. Especially galvannealed steel showed the highest protectivity. On the other hand, effect of steel itself on perforation is also observed among three uncoated steels. The EDDQ high strength steel has excellent resistance. The reason can be attributed to low manganese content and lack of surface segregation of manganese due to short time continuous annealing."
Realization of Pedestrian Protection Measures on Cars,"For the first time a working group of german universities developed an efficient, environmentally compatible and safe passenger car. The design of the UNI-CAR was specifically adjusted to the safety of persons outside the vehicle. Thus, for protecting pedestrians and drivers of two-wheeled vehicles, several of the bodywork components were primarily developed on the basis of polyurethane integral skin foam to cushion the impact of a person upon the car from outside. For instance, the car was given a reversibly deformable front end and a cushioned bonnet as well as cushioned window frames and roof edges, without impairing the design or aerodynamics of the vehicle. The report explanes the aspects of materials selection and vehicle design, the problems and experiences associated with the manufacture and application of these plastics components as well as test results."
The All-Aluminum Auto Body - A Study Based on the Porsche 928,"An all-aluminum body in a unitized construction of a sportscar has been developed as a prototype. Design features, forming, welding, and surface treatment have been studied as well as the results of the test trials. A weight-saving of 47 % compared to an all-steel body was achieved with good characteristics of static and dynamic stiffness, operational reliability, passive safety properties, corrosion resistance, noise level, and repairability."
Electric Vehicle Operational and Impact Safety Testing-Presentation of Test Results and Safety-Related Vehicle Problem Identification,"The National Highway Traffic Safety Administration has completed safety-related testing of 13 electric vehicle models which are presently on the market. This report summarizes the results of the hydraulic brake, windshield defroster, and 30 mph frontal barrier impact tests which were conducted. Performance trends are discussed and safety-related problems and defects are identified."
RIM Urethane/Vinyl Composites as interior Trim Parts,"Approximately four years ago, new production process for automobile door liners was introduced in Europe. The process consisted of stretching a sheet of unsupported, expanded PVC over the mold cavity. The mold was closed and clamped and a polyurethane structural foam mixture was injected by the RIM method through the top half of the mold. The pressure and temperature of the expanding mixture forced the vinyl to conform to the contours of the cavity thus producing a finished door liner (polyurethane foam/vinyl composite). This process showed promise but had several drawbacks. Over the past two years, cycle times have been reduced to 2 minutes, intricate surface detail has been achieved and other formable surfaces have been substituted for the vinyls. These improvements have made it a candidate product for the U.S. auto industry."
Quantitative Measurement and Predictive Techniques for Radio Frequency Interference,"A technique for measuring and predicting radio frequency interference has been developed which can quantify an individual component’s performance, The assessment of a quantitative performance objective for each component provides a means to acheive a desired level of noise rejection for the system independant of environmental variances."
Materials for Panel Damping in Motor Vehicles,This paper describes the application possibilities of materials for panel damping in modern motor vehicle construction. The basic parameters which govern damping are given; it is shown how they relate to motor vehicles. Two laboratory test methods are discussed for determining the damping performance of materials typically used in motor vehicles. Examples of the effectiveness of such treatment in the motor vehicle under normal operating conditions is presented and discussed. The influence of damping materials when combined with other typical noise control materials is shown in regards to performance and weight optimization.
Torsional Vibration Measurement and Analysis: A New Technique,"Torsional vibration measurements, while varying in complexity, are probably the least familiar type of vibration measurement. The high output demands imposed on today's engines require a complete understanding of torsional vibration. This understanding is necessary to insure proper function and durability of these engines and their components. The need for an accurate, reliable and durable measurement system that could be used for the evaluation of any engine application is essential. The measurement system has two basic components, an engine mounted transducer and signal conditioning/data reduction equipment. The transducer must be selected before other system components can be identified or developed. A prototype transducer has been evaluated and proven to meet the above criteria. Its performance has been verified with the use of redundant test methods. This instrumentation included proximity probes, linear accelerometers, an angular velocity transducer and optical methods. The linearity response of the transducer was excellent on all the subjected test set-ups. The device responded equally well to either rotating or non-rotating inputs. Eccentric locations of the transducer were shown to have minimal effects on the output response. Temperature compensation must be built into the production transducer and accurate readings can be expected from 25°F (−3.8°C) to 250°F (121°C). The future of this device looks very promising and the range of applications extend from torsional testing and machinery diagnosis to continuous systems monitoring."
Evaluation of the Acoustic Intensity Approach to identify Transmission Paths in Aircraft Structures,"The new two-microphone acoustic intensity technique has been applied to the determination of the transmission paths of sound into an airplane cabin interior. It appears that, provided sufficient care is taken in the measurements, accurate quantitative information can be obtained with this technique on the dominant paths of acoustic energy transmission. This information can be used to make design changes to the fuselage wall to reduce interior cabin noise."
Brief Status Summary for Automatic Speech Recognition at the start of the 80’s,"Automatic speech recognition has demonstrated high capability, first in the laboratory and now in field operations. This summary presents the characteristics of today’s research and commercial systems, and discusses issues and trade-offs affecting their performance. Independently conducted tests of Dialog System’s new speaker dependent, real time continuous speech recognition system demonstrated 99.5% word recognition accuracy in a task with a vocabulary of 10 digits plus 10 control words. The words were spoken by 5 speakers (3 male, 2 female) in a variety of regional American dialects against a background of heavy machine clatter and other noise."
The Effect of Noise Legislation on Vehicle Diesel Engine Design,"Proposals in both Europe and the United States for future reductions in vehicle noise limits can be expected to have radical effects on the design and installation of truck diesel engines. A review of published accounts of quietened trucks shows that mostly engine enclosure has been used. There are short term incentives for manufacturers to use this approach, but it is not the most cost effective solution in the long term and has numerous problems including that of maintaining noise levels throughout the service life of the vehicle. Greater incentive is needed for radical redesign of the diesel engine to make it inherently quiet and to minimise both the on-cost and the energy penalty of noise reduction. This paper develops the theoretical background to this problem. Starting from the basic characteristics of vehicle noise, a philosophy of noise control is developed and practical means of achieving the desired noise control are discussed."
700 H.P. TRUCK TRANSPORT,"SIGNIFICANT REDUCTION IN THE TRANSPORTATION COST PER TON MILE OF BULK PRODUCTS IS ATTAINABLE BY THE PROPER ADAPTATION OF A TRUCK TRAIN TRANSPORT. IMPROVED HAUL ROADS, GREATER DISTANCES, AND INCREASED DEMAND FOR MINE PRODUCTS AT COMPETITIVE PRICES ARE RESULTING IN A RE-EVALUATION OF ALL COST ASPECTS OF MATERIAL MOVEMENT. THE TRUCK TRAIN CONCEPT USING RELATIVELY SMALLER TIRES THAN LARGE PIT TRUCKS OPENS THE DOOR TO REDUCED OPERATING COSTS BY LOWERING CYCLE TIMES AND COST PER MILE OF TIRES AND CAPITAL INVESTMENT."
Analysis of 30 MPH Frontal Barrier Utilizing Half-Scale Metal Models,"A cost-effective early indicator of frontal barrier performance relative to government and corporate goals has been provided by half-scale metal models. These models provide direct indications of steering column kinematics and performance of specific components with respect to the windshield intrusion zone. Some indications of fuel system integrity and windshield retention evaluations have been inferred from half-scale model barrier tests. Model tests have provided early standard barrier data on vehicle crush modes and distances, barrier loads, and deceleration rates, in addition to generating data beyond what is available in standard barrier tests."
"Rollover, Ejection, and the Potential Effectiveness of Restraints in Heavy-Truck Occupant Fatalities","Rollover and ejection are associated with heavy-truck occupant fatalities almost twice as frequently as with passenger-car occupant fatalities. A panel reviewed 41 in-depth cases to assess the possible effectiveness of restraint use and the contribution of rollover and ejection to the fatal injuries. The panel's responses indicated that belt use was expected to be particularly effective in preventing fatalities resulting from occupant ejection. A review of the proportion of ejections by model year indicated that 1972 model year and newer heavy trucks have about 20 percent fewer ejections than pre-1972 heavy trucks. Ejection through the doors was reduced by 80 percent. This difference seems to reflect the effectiveness of FMVSS 206, which required stronger door latches."
The Basic Design of Two-Stroke Engines,"This informative publication is a hands-on reference source for the design of two-stroke engines. The state-of-the-art is presented in such design areas as unsteady gas dynamics, scavenging, combustion, emissions and silencing. In addition, this comprehensive publication features a computer program appendix of 28 design programs, allowing the reader to recreate the applications described in the book. The Basic Design of Two-Stroke Engines offers practical assistance in improving both the mechanical and performance design of this intriguing engine. Organized into eight information-packed chapters, contents of this publication include: Introduction to the Two-Stroke Engine Gas Flow Through Two-Stroke Engines Scavenging the Two-Stroke Engine Combustion in Two-Stroke Engines Computer Modelling of Engines Empirical Assistance for the Designer Reduction of Fuel Consumption and Exhaust Emissions Reduction of Noise Emission from Two-Stroke Engines"
Case Studies Involving the Use and Non-Use of Seatbelts,This paper presents the case study results of several actual motor vehicle accidents which occurred in the western U.S. Each case was analyzed to determine the characteristics of impact to the vehicle and the resulting occupant injuries. The most frequent injury was facial laceration from impacting the windshield. The main benefit of restraint systems lies in their ability to reduce or prevent contact between the occupant and the interior during the crash.
MF 60 TDL,This paper provides a brief review of some of the more significant features of the new Massey-Ferguson MF 60 Backhoe Loader. The machine incorporates a new “load sensing” hydraulic system and a low noise cab. These features together with the basis for its structural design are reviewed.
A History of Headlining,"This paper describes the history of the design and method of installation of cut-and-sew headlining and how it is affected by the design of the body beginning with the all-wooden construction of the first Chrysler up to the present day design. Construction of the headlining listing seam, the drafting procedure for determining their location and trim off around the window and door openings is described."
A Modular Cab for Farm Tractors,"This paper discusses the design of the modular cab for the White Farm A4T tractor. The modular concept creates new problems in cab and tractor design and has a significant effect on tractor assembly line operations. The cab is particularly quiet and well sealed. Data regarding operator noise levels are presented with comparisons shown to similar products and recent legislative activities in the area of noise control. Operator environmental control is improved with the modular concept, and performance data and specifications are discussed. The end product is the result of a close cooperative effort by the tractor manufacturer and cab manufacturer brought forth by the need to provide the customer with a greatly improved cab."
A Balanced Approach - A Lawyer's Viewpoint,"Laws controlling noise and the role of various local, state and federal agencies must be balanced against their respective interests, limitations of technology and environmental goals. Past attempts to control noise sustain the need for a balanced approach. The interest of obtaining realistic, uniform standards which are enforced by realistic, uniform procedures will advance the cause of noise control. Inconsistent standards and enforcement procedures will only impede effective noise control."
Control of Diesel Engine Exhaust Noise,"The contribution of exhaust noise to total vehicle noise is identified by isolation and near field techniques. Control of exhaust noise by using the principles of absorptive, reactive, and dispersive mufflers and their combinations is examined. Guidelines are presented to help the engine designer in the selection of mufflers within the design limitations of size, weight, and engine performance loss."
Establishment of Roof Rail Sealing Parameters for Automobile Bodies,"The reduction of sound levels in modern automobiles has called attention to wind whistles in the body side sealing systems. Methods employed to establish sealing design parameters are reviewed and the primary cause of wind noise in the body side sealing system is defined as a loss of glass-to-weatherstrip contact, produced by door glass “blowout” in vehicles traveling at highway speeds. A program of controlled dynamic testing resulted in design parameters that have produced body side sealing systems which, together with improved assembly techniques, have increased the first test-run wind noise acceptability rate for 1970 model year vehicles."
Minimum Noise Pod Design,"The necessity for realizing a major reduction in community noise from that produced by the current air transport fleet was recognized at the inception of the design of the Lockheed L-1011 Trijet wide-bodied transport. This paper summarizes the technical considerations and design procedures used to ensure attainment of the low-noise objective. It is shown that the Rolls-Royce RB.211 engine selected for the L-1011 incorporates the latest state of the art noise reduction features, including the novel shaft-slowing provision. These features result in a significant reduction in basic noise level compared to low by-pass ratio engines currently in service, even at the considerably increased size required for the L-1011. The additional noise reduction required to satisfy the low community noise objective and the FAR Part 36 limits is attained by incorporation of advanced noise suppression materials into an efficient propulsion pod design. The technology, design restraints, and system requirements which must be combined into the practical optimum minimum noise pod design are described."
An Ultrasonic Leak Detector for Automotive Field Service,"A wind noise, dust, and water leak detector has been developed for use in the automotive dealership service environment. The detector effectively indicates the precise location of leaks and presents a quantitative indication of the magnitude of the leaks in any body compartment. The new kit embodies a unique application of advanced ultrasonic detection techniques by employing an ultrasonic source and an ultrasonic detector. The device is inexpensive, relatively simple to operate and results in a significant reduction in the manhours required to detect wind noise, dust, and water leaks in automobiles."
The Case for V/STOL Aircraft in Short-Haul Transportation,"The case for a VTOL transport system is presented primarily against the background of European requirements, based on the use of fast low noise fan lift V/STOL aircraft. The main benefits are: 1. Passenger and airline appeal - time saving, convenience, competitive fares. 2. Community acceptance - reduced noise, reduced proliferation of large airports. 3. Operational advantages - flexibility, enhanced all-weather operation, safety and ATC. 4. Reduced investment - on a total system basis. The fan lift formula leads to a wide range of V/STOL aircraft to meet worldwide STOL, V/STOL, and VTOL requirements, with excellent long-term development prospects."
Legal Aspects of Military Sonic Booms,"Sonic booms from aircraft are a relatively recent phenomena. However, the law has developed to meet the new challenges and old rules of liability have been modified to fit the changed conditions. The following paper is an attempt to show some of the legal developments which have resulted from military supersonic flight, since only military or government type aircraft have flown supersonically in the United States to date. Various theories of liability for sonic boom damages have been considered by the courts and these are set forth in this article for comparison purposes. From a review of these decisions, we may be able to anticipate how future courts will handle similar problems."
Earthmoving Equipment Cab Design,"The history of the development of enclosed cab design is discussed. The advent of mechanical power meant that attention could be given to making the equipment operator more comfortable with respect to seating, work space, air conditioning, and visibility. These items are discussed, along with the improvements in rollover protection and noise control."
On the Noise Reduction of a Rectangular Box with Application to Tractor Cabs,The mechanisms by which airborne sound energy is transmitted into a vehicle cab are discussed. Airborne noise reduction of cabs is seen to deviate considerably from the masslaw behavior of the constituent materials. Various acoustical treatments are evaluated experimentally by directly measuring the noise reduction on a cab-like enclosure. The experimental results agree fairly well with available theoretical methods of computing noise reduction.
Wax Method of Determining Windshield Defroster Performance,"This paper describes a procedure for determining defroster performance using wax. The approach is a useful tool for establishing breakthrough points, and developing balanced defroster air distribution patterns prior to cold room testing. Since it can be conducted at room temperature, the wax method is considerably more convenient and can be executed with greater frequency than in a cold room. Although the wax procedure is a good barometer of the relative effectiveness of different defroster systems, and does provide valuable preliminary studies, it does not duplicate cold room conditions. The test method described, therefore, is not a substitute for, nor can it be used in place of, actual cold room testing. The paper provides information on the test facility, test equipment, test preparation, wax mixture and application, and conducting the test."
The Objective Method of Evaluating Aspiration Wind Noise,"The automobile industry places a major emphasis on reducing car interior noise levels to attain a more pleasant and comfortable ride. In recent years, improved superhighways, allowing higher car speeds, have created a rise in the aspiration wind noise due to high aerodynamic pressure differentials causing air to pass by the body seals. No longer is a car body sealed merely against water leaks. With the increased use of air conditioning in cars, the closed side windows have lowered the ambient interior noise, thereby exposing the broad band frequency aspiration wind noise. A need for an objective method for the quality control and development of body seals was imminent. This report analyzes the aspiration wind noise parameters and presents two objective methods of measuring aspiration wind noise. These methods, using a meter, replace the previously used method of subjective evaluation of the loudness of wind noise."
Rear Axle Noise Quality Inspection Method,"For many years axle plants have needed a practical testing method for rating the noise quality of rear axle assemblies before installation in cars. This report describes the development of such a test method. Creation of noise requires an energy source. The energy source of rear axle noise is the periodic variation in tooth meshing action of the gears. The frequency of axle noise is always related to tooth mesh frequency. A previous study of rear axle gear dynamics indicated the existence of a nearly vertical resonance of rear axle pinions excited by tooth meshing action. The dynamic resonant amplitude of the motion of the pinions related directly to the in-car noise quality of the gear sets. In general, other resonances within the drive line-axle housing-suspension system can be excited by gear action and produce “axle” noise. An indication of the amplitude of the resonant member (or another responsive member within the system) directly relates to the relative noise quality of the gear set. To verify this relationship, the dynamic pinion response of a group of 30 axle assemblies was measured. The in-car noise ratings were obtained by using a jury of three experienced raters. The correlation between the dynamic pinion motion measured in a test stand and the in-car noise ratings was found to be very good, indicating the feasibility of using this method in axle plants. A statistical analysis was made of the data to determine the degree of correlation and the validity of the data. Details of the test stand operation, noise rating method and tests results are included in the report."
The Uniflo Personal Rapid Transit System,"A personal rapid transit system has been developed, capable of providing urban areas with public transportation service that is competitive with the automobile in speed, availability, accessibility, and comfort. The system contributes no pollution in terms of air, noise, or vibration; it is relatively small in size; and it can be installed elevated, on grade, or below grade. These qualities make it an acceptable addition to a community. Because this personal rapid transit system is highly automated, a significant reduction in the amount of labor required to provide transportation service is anticipated. This could mean that it would again be possible to make money moving people."
A North European Tractor Cab,"A farm tractor protection cab made of thin steel sheet pressings is described. The cab is designed and produced using entirely automotive-type procedures. Curved glasses and a dampening suspension of the glasses are found to be an important means of achieving a low noise level in the cab. Using the pressing technique when producing a steel cab makes it possible to give the various cab details rigidity with a minimum of material. When welded together, these details form a very stiff cab body, which gives the necessary mechanical strength. The curved surfaces, the radii, and the round forms, which from a tooling point of view are natural for pressed steel parts, also have a vibration-dampening effect on the entire cab construction, thus making it easier to design a quiet tractor cab. Mounted on a farm tractor of conventional design, the cab meets the noise rating number ISO N85."
Door Crashworthiness Criteria,"A study of the biomechanical factors concerned with the design of side structures and doors for crashworthiness has been made. Questions regarding optimum stiffness, location of reinforcing members, effect of armrests, and padding have been answered within the framework of injury criteria models. Results of animal studies, cadaver studies, and anthropometric dummies have been combined to produce injury criteria for lateral impacts to the head, thorax, and abdomen. Impacts were applied utilizing a specially designed “air gun” in a laboratory environment emphasizing reproducibility and control. Full-scale crash simulations were performed on an impact sled to verify the results of the more specialized tests and analyses. Scaled models of current production doors were used in the animal series. Scaling relationships for various species of animals have been developed and extrapolated to man. Significant differences in right and left side tolerances to impact were noted and detailed. Additional verification of the Maximum Strain Criteria Model (MSC) is reported. Critical impact velocities for various body sites have been developed for several categories of impact and are presented in ways thought to be most meaningful to designers."
Automotive Safety in Review,"This paper broadly surveys the continuing research and development by automotive engineers in designing safer automobiles. Door latch redesign, seat belts, energy absorbing steering columns, laminated windshields, energy absorbing instrument panel and its knobs and levers, dual brake systems, seat back impact absorbing tops, head restraints, and bias-ply tires are among the improvements discussed. Passenger restraint remains the most important factor in saving lives, however, and the public has been careless in using such systems. Passive restraints, such as the air bag, are under development. The need for good driver training programs, the problem of alcohol, and the need for continuing improved highway design are also touched upon."
Power Plant Design for Noise Suppression,"The design configuration of turbofan power plant installations for commercial aircraft is significantly influenced by the requirement for reduced aircraft noise. This paper describes the design evolution of the installation of the CF6, high-bypass ratio engine in the McDonnell Douglas DC-10 as it was influenced by the need for noise suppression measures. The candidate alternatives and the basic trade-off criteria leading to the selected configuration are presented. This paper also includes some considerations associated with choice of material, construction, and design techniques applicable to various areas of sound treatment within the nacelle."
Noise Considerations in the Design of Advanced Subsonic Transport Turbofan Engines,"The problems and choices in the design of an advanced subsonic transport turbofan for reduced noise and improved aircraft performance are examined in this paper. The effects of bypass ratio, fan pressure ratio, and fan tip speed on jet noise, fan noise, and acoustic treatment suppression are described. The results do not indicate a clear optimum bypass ratio considering the effects upon installed engine performance and weight as well as acoustic performance. Low fan tip speed designs with the associated high aerodynamic loading are compared to high tip speed low loading designs. Other factors affecting noise such as the installation and other noise sources are discussed. The long duct installation is indicated to have potential advantages over the short duct separate flow installation. The problem of assuring that growth models of an engine also have low noise is discussed."
Airtransit's First Six Months of Operating The Canadian STOL Demonstration Service,"A complete STOL (Short Take-off and Landing) system is currently providing public transportation service between the urban centres of two large Canadian cities. Passenger and public reaction, plus operating experience in a competitive environment is providing some interesting data, useful in developing future STOL systems as an important component in the improvement of transportation in general. The Demonstration is showing that STOL systems are capable of quickly providing fast, convenient, short-haul service, while at the same time respecting the composite concerns of society, encompassing air-pollution, noise, land-use, energy-consumption and economics."
"Planning, Implementation, and Operation of the Philadelphia-Lindenwold Line","Through careful planning and implementation the Delaware River Port Authority has developed a highly successful mass transit system, the Philadelphia-Lindenwold Line. They have realized their goal of creating a rapid transit line which would win the patronage of potential passengers and be constructed and operated within the economic resources of the Authority. The one to six car trains are operated by a one man train crew who is, in fact, part of the automated or computerized process. He notifies the computer as to the length of the train; opens and closes doors; determines the length in time of each stop; initiates acceleration; and can eliminate station stops. The computer prevailing determines train speed for each track section and right of way conditions; causes the train to decelerate at the optimum rate; and stops at the station with the center of the train at the center of the platform. The Lindenwold Line has demonstrated that motorists will leave their cars if superior transportation is provided; quality transit service can reduce air and noise pollution and conserve energy; traffic congestion can be reduced; technology is now available to create desirable rapid transit service, and that rail rapid transit can be planned, constructed, and efficiently managed to meet operating and maintenance costs out of the fare box."
NASA REFAN PROGRAM STATUS,"The objective of the refan program is to demonstrate the technical feasibility of substantially reducing the noise levels of existing JT8D powered aircraft. The program consists of the design, manufacturing and testing of the refan engines and modified nacelles and airplanes. Experimental testing has been completed for the refan engine both at sea level and at altitude conditions. Ground testing for the B727 side- and center-engine installations and flight testing of the DC-9 with refan engines and acoustic nacelles have been performed. Analyses of the test results are in progress. Preliminary results presented in this paper show that substantial noise reductions were achieved."
A Technique for Measuring Interior Wind Rush Noise at the Clay Model Stage of Vehicle Design,"A technique has been developed to evaluate interior wind rush noise during wind tunnel tests of full-size clay models of vehicles. A small, box-like enclosure with acoustic characteristics made similar to those of a typical vehicle interior is inserted into the clay model behind an actual front sideglass. The wind rush noise coming through the sideglass is directly measured by microphones located within the enclosure. The technique can readily detect wind rush noise changes due to body modifications in the vicinity of the windshield-pillar. In addition, the wind tunnel results agree well with those found on-road."
Interior Noise Problems of Small Diesel-Powered Buses,"This paper discusses interior noise problems characteristic of the combination of diesel engines with typical small bus geometries. One noise problem is the potential for low-frequency resonances. Natural air vibration modes for typical small bus interior dimensions are calculated and shown to give frequencies that can be stimulated by noise and vibration at engine firing frequencies. Measurements of noise and vibration at resonance are given. Other noise problems are associated with internal front engine covers, and leaks and low transmission loss paths in the console area. Some practical suggestions, with examples, are given to reduce interior noise."
Application of Microprocessors to the Automobile,"This paper describes microprocessor technology as it may be applied to the automobiles of the future. The microprocessor requirements described in this paper were generated as a result of the evaluation of the Alpha IV vehicle system which utilizes a solid-state, digital 4-bit, microprocessor to perform several vehicle control and display functions. The development of the Alpha IV system encompassed not only the interface circuit design and microprocessor programming, but also, the derivation of the digital algorithms and control laws for the functions which have traditionally been performed in an analog fashion. The control functions performed include: Cruise Control, Four-Wheel-Lock Control, Traction Control, Speed Warning, Speed Limiting, Ignition Spark Advance and Dwell, Automatic Door Locks, and Anti-Theft System. The display functions include: Speedometer (both analog and digital), Odometer, Trip Odometer, Tachometer, Clock, and Elapsed Time."
The Rovac Automotive Air Conditioning System,"The ROVAC air conditioning system, a new system that employs air as the refrigerant, is a combination rotary compressor/expander unit. A prototype has been modeled, designed, fabricated, laboratory tested, and field tested in a full size four door 1973 Dodge Coronet. The description of the new system, the analysis, design and actual test results are reported here. The objective of the engineering program was to demonstrate and prove the capability of the ROVAC system to effectively and efficiently air condition automobiles. The prototype system installed in the Dodge Coronet produces delivered cooling capacity on the order of one to one and a half tons per thousand rpm and has produced delivered coefficients of performance at relatively high humidity levels (150-180 grains water per pound of dry air) rivaling the best developed conventional vapor compression air conditioning systems. While the present system reported herein has not reached the levels of performance predicted by detailed computer models, continued hardware improvement is facilitating actual performance very near the levels predicted to be practically achievable. During actual in-car jury tests, the prototype ROVAC air conditioning system brings the average passenger compartment temperature from a thermally soaked condition of 107°F down to 72°F in less than two min with five passengers at an average road speed of 30 mph."
Evaluation of Two Convex Mirror Systems by Government Drivers,"A nationwide field study of two types of convex mirror systems was made by the National Highway Traffic Safety Administration (NHTSA) with the cooperation of the General Services Administration (GSA) for a 10-month period starting in January 1974. One convex mirror system, called the Type I system, consisted of a non-adjustable convex mirror on the right fender, the original outside mirror on the driver's door, and a larger inside mirror. The Type II mirror system consisted of an adjustable convex mirror mounted on each fender and the original inside rearview mirror. A total of 515 Federal employees evaluated these two convex mirror systems at six major test locations to provide 627 questionnaires. An analysis of the questionnaires shows that drivers preferred the Type II convex mirror system over the Type I. From comments received, it seems that the drivers objected mostly to the non-adjustable feature and restricted field of view of the Type I system rather than to the fact that it was only a one-convex mirror system as compared to a two-convex mirror system. However, neither convex mirror system was rated as highly as the periscope system was evaluated in a previous field test of 50 periscope equipped GSA automobiles (1)*. This suggests that drivers would prefer unit magnification mirror systems with larger rearward fields of view over convex mirror systems with roughly the same view; nevertheless, drivers also prefer the convex mirror systems tested over conventional mirror systems because the convex mirrors provide greater rearward visibility."
Acoustic Performance of a Large Semi-Anechoic Test Chamber,This paper describes a large indoor semi-anechoic facility for testing construction machines and discusses the procedures used to determine its acoustic performance characteristics. Data were obtained and analyzed employing controlled pure tone and broad band noise sources with varied microphone distances and elevations. The ground-plane microphone proved to be the most practical way to obtain representative data. Comparisons to an outdoor test site are included.
J58/YF-12 Ejector Nozzle Performance,"The Lockheed YF-12 aircraft uses a blow-in door ejector nozzle, which consists of a variable area, primary nozzle mounted on the afterburner of a Pratt & Whitney Aircraft J58 engine and blow-in doors, a convergent-divergent spool piece, and variable exit area free-floating flaps integrated into a Lockheed YF-12 airframe. Performance data from cold-flow, wind tunnel models and hot-flow, static stand models were correlated and compared with actual flight test data. It was found that these data showed agreement when both internal thermodynamic and external aerodynamic effects were considered."
Environmental Guidelines for the Designer of Automotive Electronic Components,"This paper describes the climatic, dynamic, and electromagnetic environments in which electronic packages must survive at various locations in the automobile. Previously available climatic data is organized to be useful to the designer. New dynamic information that provides power spectral information for various locations on the automobile is presented. The electromagnetic information includes power line transients, voltage regulation, and steady-state noise information."
Design of Elastomeric Vibration Isolation Mounting Systems for Internal Combustion Engines,"The Internal Combustion engine, by nature a dynamic vibration source, requires a properly designed flexible mounting system to isolate those disturbing vibrations. To do this it is necessary to consider all six degrees of freedom of the engine and to use the computer to determine vibratory outputs for given inputs. An example of such a computer program is given. In addition, the design of a mount system requires consideration of static and dynamic force resistance and reduction, motion limitation, environmental resistance and service life requirements. Elastomeric mounts can provide substantial noise reduction but due to the complexity of the noise problem, the prediction of the actual amount of reduction is more of an art than a science. High frequency problems caused by “standing waves” in an elastomeric mount are very much less likely to occur than those due to structural resonances. Examples of noise reductions due to the addition of elastomer mounts, on some actual vehicles, are given."
Safety Performance of Securiflex Windshield,"An improved windshield with a special, thin, plastic inner surface attached to the inner surface of a three layer windshield similar to those used in the United States minimizes lacerations from occupant impact to the windshield during a collision. The plastic coats the sharp edges of the broken glass preventing or minimizing laceration. It was evaluated by comparing its laceration performance with that of a standard windshield in simulated barrier crashes at velocities up to 65 km/h. No lacerations resulted from impact to the Securiflex windshield at Barrier Equivalent Velocities up to 65 km/h. Substantial laceration resulted at velocities above 20 km/h with the standard windshield. It is concluded that the Securiflex windshield essentially eliminates lacerations in the particular vehicle involved at velocities up to at least 65 km/h."
Less Noise From Diesel Trucks,"An indepth study to reduce noise produced by a typical highway diesel truck is being conducted to determine levels and costs attainable by practical means. Truck noise reduction involves isolating several individual noise sources, that is, fan, exhaust, engine-radiated, intake system, and others, and developing means to reduce each. Tire noise and major engine revisions are not considered in this project. Goals of 78 dB(A) (per SAE J366a) without engine enclosure and 75 dB(A) with engine enclosure are believed possible on the vehicle configuration being studied. This project is sponsored by the U.S. Department of Transportation Office of Noise Abatement, and industry."
Propulsion Integration for a Hybrid Propulsive-Lift System,"In a discussion of STOL vehicles with conventional high-lift devices, the need for efficient power-augmented lift systems is presented and the implications of quiet operation are noted. The underlying philosophy of a promising hybrid lift system with major interactions between aerodynamic, thermodynamic, acoustic, and configuration design technologies is derived. The technique by which engine and airframe-related characteristics for this application may be matched in an optimum manner is described and illustrated by describing the features of a particular short-haul commercial STOL vehicle."
Human Engineering Applied to the Design and Grouping of Electrical Controls in the Motor Vehicle,"A study has been made of motor vehicle driver environment in order to determine the most desirable design features and the optimum grouping of electrical controls conducive with minimum conscious thought and physical effort in location and operation under any given set of conditions. Consideration is given to the psychological aspects of control operating noise level and action “feel,” to styling and standardization of layout with the ultimate objective of driver fatigue reduction, and to a worthwhile contribution in road safety improvement."
Sound Attenuation in Operator Enclosures,"This paper outlines parameters for the design of operator's enclosures (cabs), with special reference to noise control. Specific suggestions for the solution of noise pollution include shock mounting of the cab, plugging all holes through which noise can enter, attenuating large sheet metal areas by damping, effectively using large amounts of glass, diverting the exhaust outlet away from the cab, providing a fan shroud, not mounting sound generating components to enclosure walls. Such steps should reduce the sound level by 15-20 dB, but will add 12-15% to the overall cost of the enclosure."
Interior Window Fogging - An Analysis of the Parameters Involved *,"Many factors are directly related to the occurrence of window fogging and flash fogging. The pertinent variables affecting the problem are identified and discussed. In simple terms, fogging is dependent upon the difference between the dew point temperature of the interior environment and the glass surface temperature. Several dew point and glass temperature curves have been computed which typify various operating conditions. Alternatives that will help to eliminate fogging are discussed."
New Methods of Reducing Noise in External Gear Pumps,"The noise from external gear pumps has been significantly reduced by a new design which consists of two sets of gears, half the width of a standard gear, and offset about 1/2 pitch. The new pump makes use of a housing which is externally basically the same as a standard pump. This paper presents test stand and field measurements of the pump."
Advanced Olympus for Next Generation Supersonic Transport Aircraft,"The paper summarises the background studies which have led to the proposal for an advanced Olympus engine, with mechanical noise suppression, to power the next generation supersonic transport aircraft. The recent international collaborative test programme on real engine scale ejector suppressors is described and reference is made to other Rolls-Royce experimental work at model scale. The envisaged changes to the design of the in-service Concorde engine are outlined and some installation aspects are discussed. It is emphasised that detailed refinement of the engine cycle must depend on the result of aircraft/engine integration and optimisation studies."
Bulldozer Noise Control,"Bulldozer noise is the most serious noise problem for surface miners today. Not only are bulldozers the most common type of mobile equipment, but the majority of their operators are also exposed to more noise than current federal regulations allow. In 1977, the Bureau of Mines responded to this problem by developing retrofit noise control treatments which reduce the noise that reaches the operator. These treatments were specifically designed to be readily installed in the field at low cost. In 1978, these treatments were installed on two Caterpillar D9G’s in surface coal mines to demonstrate the noise reduction that can be achieved under actual production conditions. This paper presents the results of the field demonstrations."
Side Impact Sled and Padding Development,"IN A ONE YEAR LABORATORY STUDY, a side impact sled was designed, built, and validated. Using the sled and a newer generation of side impact dummy, a number of energy-absorbing materials were tested and superior materials identified. Initially this study concentrated on the crash test data for a number of V.W. Rabbits crashed in a previously completed study. The crashed vehicles were obtained, and interior crush tests were performed with a specially designed body form. This was done to determine how the effective stiffness (as seen by the occupant of the struck vehicle) of the interior door increases as the bullet vehicle presses against the interior door trim from the opposite side. An acceleration-type sled buck was then designed and built with an “interior door” mounted to mimic the interior stiffness determined from the crush tests. The sled was dynamically tested with a Haversine sled pulse similar to the door crash pulse. The sled was validated by reproducing the crash environment of a car-to-car collision. The criteria considered for matching the two were: (1) acceleration-time curve of the interior door, (2) the velocity-time curve of the interior door, (3) kinematics of the Part 572 surrogate, and (4) accelerations on the surrogate."
Evaluation of Pelvic Fracture Tolerance in Side Impact,"Pelvic fracture is a typical lesion sustained by the occupant of a vehicle involved in a lateral impact collision who is seated on the impact side. If this fracture is generally not severe by itself, it is nevertheless often associated with severe abdominal lesions. Study of injury mechanisms in lateral impact collisions shows that there are two ways of ensuring a better protection of the occupant in this type of accident: first by preventing intrusion so that the contact velocity “occupant/inner door” is decreased, secondly by absorbing the shock of the occupant against the inner door, especially at pelvis and thorax levels. It is necessary to have a good knowledge of human tolerance to fracture of the considered body segment in order to determine the mechanical properties of the padding material. The aim of this study is to determine the tolerance of the human pelvis. This study takes into account results of 36 impact tests against the pelvis of 10 cadavers and proposes injury criteria values to characterize the risk of pelvic fracture."
Vehicle Design Considerations For Older Drivers,"During the next half century, the older driver population will increase dramatically as the Baby Boom becomes a Senior Boom of similar proportions. Therefore a proper understanding and awareness of the changes that take place in our vision and cognition through aging, can be useful to engineers designing automobile systems for a more mature market. How these changes brought about by aging affect our interaction with such vehicle systems as controls and displays, mirrors, head-lighting, seating, and entry and exit is the subject of the following discussion. Recommendations also are made, based upon the current literature, for modifying these vehicle systems to meet the needs of older drivers."
Physical Characteristics Of Heat-Absorbing Glass And Their Influence On The Driver,"The characteristics of heat-absorbing glass for passenger cars are described with regard to climate perception and visibility of the driver, both of which are important aspects of active safety. Such modern types of glass reduce the transparency to heat and at the same time maximise light in the visible spectrum. To be in a position to quantify the advantages and disadvantages in the visible spectrum as regards transparency, dazzling, reflectance and diffused light, practical road-test runs were carried out on the same public roads under different conditions in light and climatic environmental. The tests comprised physico-technical, physical and psychological data with regard to driving behaviour of and strain on the drivers. The results confirm the predominance of advantages of heat-absorbing glass and provide, indications as to optimising the side and rear windows by increasing the degree of heat-absorbing."
Investigation of Vehicle Side Impact Stiffness - Comparison of Static and Dynamic Tests,"The purpose of this investigation on vehicle side-impact stiffness and the comparison of the static and dynamic tests was to contribute guidelines for a final test procedure with two advantages: to be, on the one hand, simply practicable and reproducible and, on the other hand, to provide results corresponding as close as possible to real accidents. Additionally, the investigation emphasized testing of side parts significant to the objectives of the test: door only, door and sill, or door, sill and roof. New cars as well as heavily rusted vehicles were used for the test. Therefore this paper also treats the question of what degree a test of only new cars will be useful, without considering the state of corrosion of older vehicles."
A Study of the Vehicle Acoustic Control for Booming Noise Utilizing the Vibration Characteristics of Trunk Lid,"An acoustic control technique for reducing booming noise caused by road surface roughness is described. This noise, mainly in the frequency range between 25 and 40Hz and accompanied by a pressure sensation, is closely related to suspension vibration characteristics and the acoustic response of the vehicle compartment. A reduction method which separates the highest acoustic response from suspension resonance in this frequency region is proposed. An acoustic simulation model is used to estimate the effects of the luggage compartment on this noise and of trunk lid vibration characteristics in optimizing acoustic properties of the compartment. As a result, a frequency region for trunk lid resonance which lowers booming noise is obtained. Estimated booming noise reduction is experimentally confirmed in road tests. A study of human auditory characteristics is also conducted to ascertain the frequency range and booming noise level which produce uncomfortable sensations."
Prevention of Frost Formation on Automobile Glazing,"Energy radiation during clear mornings causes a temperature drop on outdoor surfaces. If this drop is big enough, moisture will condense and lead to frost formation during cold weather. This is a nuisance and a safety risk for the driver when it occurs on car windows. If the surface of the glazing is coated so that the emissivity within certain spectral bands is low, frost formation can be prevented in most situations. In the autumn of 1986, Volvo introduced a windshield on these lines. Tests indicate that the number of mornings when scraping is necessary is reduced by more than 80% in the Swedish coastal climate."
Special Considerations in Outfitting a Space Station Module for Scientific Use,"This paper addresses some of the key issues involved with outfitting a space station module for life sciences research, namely the integration of a large diameter centrifuge for holding control specimens at 1G (or fractions thereof); accommodating international participation in the design and construction of key elements of the lab module (including the module itself); and maintaining biological isolation between the experimental animals and the crew. Several design concepts are presented that address these specific issues. Centrifuge vibration - once thought to be a major problem in a station that also houses materials technology experiments - will be virtually eliminated by the use of an active magnetic suspension and automated rotor balancing. Bioisolation is provided by housing the animals in special isolator cages and performing all experimental work in a laminar flow isolation hood."
Performance Criteria for Speakers in Digital Car Audio Systems,"In an automotive sound system, the environment plays a major role in the total acoustical performance. Most of the design goals are the same as in home entertainment systems. However, the presence of road noise and restricted space availability for the speaker location must be considered as design criteria. High excursion requirement to overcome the masking effects introduces several nonlinearities. Since cars behave differently under dynamic conditions, speakers must be designed selectively for high performance."
Machine Vision Correlation to Master Gauges,"Machine vision technology is a tool being utilized in the new GMT-400 pickup truck Body Shops for process monitoring and control. These real-time Machine Vision Dimensional Gauging systems monitor 100% of the production's critical build features such as door and window openings, hinge locations, and fender mounting brackets, Traditional gauges typically can provide data on only a small sample of production −1% or less. Correlating the machine vision systems to master gauges allows accurate data to be collected on every job as it is being built. This complete dimensional control data provides information for process monitoring as well as a means to detect tooling adjustment requirements and the ability to detect build problems, even if they occur intermittently. Several methods of performing this correlation have been investigated, with the goal being to define a correlation procedure that works well in the plant environment."
Study of the Hydrodynamic and Viscoelastic Properties Affecting the Surface Appearance of Extruded EPDM Compounds,"An experimental study was aimed at understanding the mechanisms establishing the surface appearance of extruded EPDM compounds for applications where aesthetic appearance is critical. The study shows that surface appearance is directly proportional to the extent of viscous heating in the die, and hence can be controlled by the degree of shearing action, either by screw and die design or screw speed. Both surface appearance and extrudate swell can be related to the viscoelastic properties of the EPDM polymer through the dimensionless Deborah and Euler numbers. Knowledge of the parameters affecting surface appearance can be applied to better design of EPDM polymers for such applications as automotive seals for windows and doors, which are comprised of both dense and sponge extruded profiles."
A Body Switching System using the SAE J1850 (CarLink) Protocol,"The recent approval by the SAE Motor Vehicle Council of the serial protocol J1850 is a major milestone in the development of an open and flexible network approach to vehicle wiring. However, it is now necessary to evaluate the practical implementation of the protocol in some real vehicle applications. This paper describes one such exercise which considers a three station installation including the doors and a central body computer function, together with a diagnostic capability. It is, of course, anticipated that this simple system will be extended to include other areas of the vehicle as confidence is gained in its performance and the benefits of system integration are realised."
Numerical Simulation of Air and Heat Flow in a Heater Unit,"Heat flow phenomena in the heater unit of an automobile air conditioning system have been analyzed by direct simulation, solving the Navier-Stokes' equation in which an upwind finite difference method of third-order accuracy is adopted with a 2-D model. The analytical results presented visually to ascertain air and heat flows in the heater unit. In addition, a comparative experiment was carried out to compare test results with calculated results. The heater unit in the air conditioning system controls the temperature of air in the automobile. The heater unit consists of a unit inlet, outlet, mixing door and heater, as shown in Fig. 1 (1). Air, entering the heater unit inlet is mixed with warm air heated by the heater to a suitable temperature, and then blown out of the outlet. The shape and size of the heater unit are restricted by the size of an automobile's engine compartment and the layout of other auxiliary devices. Therefore, warm air must be mixed with cool air efficiently in this limited space. The shape of the heater unit has been determined based on experience. The development of the heater unit requires a fairly long period of time and much labor. To improve the efficiency of this development process, the authors quantitatively analyzed air mixing phenomena in the heater unit. The Navier-Stokes' equation was solved directly by the third-order accuracy upwind method."
A Low Cost Door Control System,"The ability to achieve a low-cost replacement for the conventional wiring harness is difficult when considering a multiplexing system designed for a minimum wire count. This paper looks at a specific problem - getting a large number of cables across the ‘A post’ into the driver's door, and considers the issues affecting the design of partially multiplexed solutions. A summary of the technical and cost implications of the new system is included."
"Electrochemical Metallizing, Tooling Design, and Application","Electrochemical metallizing (ECM) has been widely used in aircraft maintenance and OEM applications, but is far from reaching it's potential. Although ECM has been around for more than twenty years, it still represents a small part of metal finishing as a whole, thus making information describing the process not readily available. Most of the problems experienced with the process, aside from solution contamination, stem from improper tooling design, and will be the focus of this paper. Tooling and other areas covered will be as follows: 1 Anode design: choosing proper anode design for the job. 2 Flow-thru anodes: for more efficient distribution of electrolytes. 3 Precision build-ups: plating to size. 4 Solution and anode cooling: to prevent over-heating of solutions at the anode/work-piece interface and the effects on the deposit. 5 Masking techniques: how to make the tape work for you by reducing high and low current density problems. 6 Heavy build-up: depositing .050″ or more. This paper will cover areas which help us get closer to creating ideal ECM conditions, therefore improving repeatability and opening doors to new applications."
Fabrication of Interior Door Trim Using Ceramic Dies,"To produce high quality appearance interior parts, precise pattern forming or gloss reduction of three-dimensional door trim cover materials are utilized. In the preparation of formed trim cover using polyvinyl chloride (PVC), prior pattern forming on original cover material or post-pattern forming with vacuum forming dies are employed. In the latter case, the die is usually made of epoxy resin. Although vacuum holes are prepared on the resin die as necessary, the lack of uniformity in air permeability causes inferior pattern transferability. In this development, special porous ceramic die is used as die material so that trim cover material can be evenly sucked through the fine pores on its surface. As a result, a door trim forming die of superior pattern transferability has realized. The features of this- die are as follows. 1) The addition of metal powder, metal fiber, and binder to the ceramic powder has achieved well balanced air permeability, compressive strength, and dimensional change rate. 2) The uniform, high air permeability can produce deep and precise grain and stitching pattern (patterns) transfer with a low surface gloss rate. A work area with a stable surface quality can also be secured. 3) A shorter lead time of manufacturing and lower die making cost have achieved."
A Steel-Plastic Hood Concept for Passenger Cars,"A novel hood of steel and plastic has been designed to achieve an effective balance between weight and cost. The design concept uses a thinner (lighter weight) 0.024-inch-thick steel sheet for the outer component and a compression molded SMC inner component combined with an inner very thin (0.015-inch-thick) steel sag pan. Cost estimates of the hybrid hood were made using a mathematical cost model developed by MIT and indicated costs similar to an all-steel hood, but significantly lower than for an all-SMC hood. In addition, the weight of the hood is less than the all-steel hood. The steel outer optimizes the surface characteristics of the hood and maintains appearance compatibility with other exposed steel body panels. The inner steel sag pan is used in membrane tension to work with and complement a minimal weight SMC panel. The inner SMC portion also acts in compression and bending to significantly limit panel deflections and greatly increase the assembly's stiffness. Key adhesive bonding tests were successfully conducted with bare and coated steel substrates selectively bonded to SMC during the SMC molding cycle. The encouraging engineering analysis of the novel hood and the attractive combination of low weight and cost suggest that similar benefits could be derived from combining steel and plastic in other two-piece assemblies (deck lids and doors)."
Development of Practical Multiplexed Wiring System,"This paper describes a new approach to solving various problems inherent in conventional multiplexed wiring systems. These problems include the fact that the quantity of cut leads, which determines the cost, is not reduced even though the bulk of the wire harness is decreased. Another problem is that the communications system has a very complex configuration. With the approach proposed here it has been found that the number of cut leads can be reduced by housing the communications circuits individually in each piece of electrical equipment. This can be accomplished by grouping together the wiring in which the signals activating electrical load units all flow in the same direction. Custom LSI circuits have been developed to simplify the communications circuits. All of these developments have been combined into practical multiplexed wiring systems for controlling the power Windows, automatic door locks and power seats."
Energy Management of Thermoplastic Composites in Automotive Instrument Panels/Components: An Option for FMVSS 208,"Federal requirements for unrestrained occupant protection, recent automotive designs requiring increased part integration and modular assemblies, high costs for tooling and secondary operations, and intensifying competition are primary incentives for automotive engineers and designers to consider thermoplastic composite materials for replacing and complementing many current metal parts. Nowhere is the scrutiny of material choice more significant than in parts where energy management and stiffness are major design concerns; parts such as bumper beams, door structures, seating, and instrument panel components. Thermoplastic composites offer designers materials which are lightweight, perform consistently over wide temperature ranges, and manage energy to meet part performance requirements."
An Integrated Door System Using Multiplexing,"Many separate door systems are integrated into a single functional system that uses multiplexed wiring techniques. This system shows advantages over conventional techniques in many areas. Some of the advantages are: Reduced wiring, less part numbers, reduced car-to-car variability, increased functions, better build, and better servicing."
Door Module of Polyurethane: A New Concept,"This is a specification for a car door made of polyurethane plastics with the following features: Door body of GF/PU combined with an integrated metal support. The outside door panel from the waist line down to the bottom edge of the door is fixed to the door body with an adhesive-bonded joint. A metal support designed as a stiffening frame and a supporting element for fittings. Permanently bonded, form-fitting window combined with multi-purpose window that can be lowered. The costs show that this concept is able to compete with conventional metal solutions."
Ten Years of Plastic Applications in Fiat Car Exterior Components: Review and Preview,"The paper outlines the evolution of the plastic component in Fiat passenger cars as far as the outerpart is concerned. A first section is devoted to bumpers and their evolution into front and rear ends where different materials (thermosetting and thermoplastic ones) and finishing procedures (grained in-mass pigmented or smooth and painted) were adopted. Further the evolution of a rear door is quoted dealing with the design concept of two wall adhesivated structure and with the selection of the appropriate manufacturing technology. In conclusion, taking also care of the service performances, trouble shooting and technology evolution during the last ten years, some considerations are quoted, demonstrating that the approach to fully plastic body panels will require in each case peculiar studies and development works."
Car Occupant Ejection in 919 Sampled Accidents in the UK-1983-86,"Vehicle and injury data from 919 accidents in the UK are analysed for frequency, cause, and consequences of occupant ejection. Injury consequences are shown to be severs, the fatality rate rising with ejection by a factor of 4.3 among unrestrained occupants, and evidence is offered that ejection prevention would reduce injury levels to those of not-ejected occupants. The rear window was found in this sample to be the most frequent ejection route, followed by side doors, side glass, and the tailgate. Complete ejection was slightly more frequent from hatchbacks than from saloons. Door openings are analysed for frequency and release mechanism, and the ejection risk for exposed occupants is seen to be very high. These results are considered in relation to possible countermeasures, of which restraint use is shown to be by far the most effective, and bonded laminated or glass-plastic glazing is particularly recommended for rear windows."
New Developments in Materials and Fabrication Processes for Automotive Interior Trim Skin Materials,"Automotive interiors consist of sandwich type components (e.g., instrument panel, door trim, headliner); hard trim (e.g., pillar trim) and functional solid components (e.g., load floor, seat backs, etc.) The intermaterials competition among new processes for fabricating these 3 types of components were described previously (1)*. This paper examines new developments specifically in the area of skin materials used for the sandwich type interior trim components."
A Survey of Vehicular Side Wall Constructions,"Starting with the vintage flat built up side wall constructions in the form of door and quarter trim panel trim, this paper discusses the resinated felt, wood fiber, filled plastic extruded sheet, injected molded, molded in place, reinforced reaction injection molded (RRIM), structurally reinforced reaction injection molded (SRIM) side wall constructions. It further discusses cover materials for interior trim in the United States, Europe and the Orient. The future trends along with modular doors are discussed. A conclusion is made regarding the responsibility to be undertaken as assigned by the end using customer."
Application Study of Vibration Damping Composite Steel Sheet to the Car Body Panels,"The vibration damping composite steel sheet was improved in properties such as dependence on temperature, bending rigidity, press formability and spot weldability and compared with damping materials currently used by reviewing composition and adhesion strength of the resin and the mechanical property of the steel skin sheets. By applying the above-mentioned materials to the floor and wheel-house panels, a reduction in noise and vibration was obtained in the application test, and improvement in door shutting noise was also revealed when applying these materials to the door panels."
Relationship Between the Physical and the Psychoacoustic Parameters of the Sound Field in an Automobile,"A new method of measuring physical factors that prescribe the sound field of the vehicle interior has been used to evaluate the differences in the sound field for 4 types of two-channel loudspeaker systems, which are installed in the front part of the vehicle. The physical property which prescribes the sound field inside the vehicle is related to the directional properties of the sound, such as lateral, forward and backward component of the early reflection sound energy. Psychological experiments have also been conducted under the same conditions as that for the physical measurement, and then the correlation between the psychological factor and the physical factor has been examined. The following conclusions have been reached: (1) L/M (the ratio of low frequency sound energy vs. medium frequency sound energy) is highly correlated with spatial impression. (2) F/B (the ratio of forward directional energy vs. backward directional energy) greatly contributes to the preference of the sound quality. (3) L/R (the ratio of left directional energy vs. right directional energy) is highly correlated with the localization (left and right) of the sound image. (4) Among the four types of two-channel loudspeaker systems, “mounted in the front doors” has a wide sound image and is more preferable in comparison with the other loudspeaker locations."
Status and Update of MVMA Component Testing,"At the Tenth ESV Conference, MVMA reported on the development of a component side impact test device developed for MVMA by MGA Research Corporation. Since that time, the test device has been modified by MGA to improve its biofidelity. Testing has shown that the modified device better meets the force-time corridors derived by MVMA from cadaver drop test data. The improved test device was used to test twelve 1985 Ford LTD doors at speeds of 25.7 and 37 km/h. The interior door surfaces were trimmed with either thin fiber board or foam padding identical to doors in vehicles tested by MVMA using NHTSA's full-vehicle test procedure. The tests showed that the MVMA device is simple to set up and run, is highly repeatable and easily discriminates between the unpadded and padded doors. A major issue for future research and development is how to select a priori a component test device impact speed which can account for differences in car size and side structure stiffness."
Development of a Rigid Passenger Safety Compartment Made of Composite Material-Application for Front Door Frames,"Based an extensive preparatory work and analyses, suggestions have been drawn up with regard to solutions for front door frames in the following regions:- door hinge mountings, seat belt anchorage mountings of B pillars, cross sections for the top of A pillars. At the same time as the design work, FEM calculations should be carried out to ensure optimization of the concepts. Economy reasons and experiences in production runs point towards a very strong fibre glass-reinforced door frames manufacutred in the SMC procress. The complete door frame is examined in comparison with geometrically similar sheet metal parts on a test frame and in the vehicle."
The Effect of Door Topography on Abdominal Injury in Lateral Impact,"Seventeen left lateral impact experiments were performed using anesthetized swine to determine the biomechanics of injury production in this impact mode. Two series of eight animals were used and one animal served as a control. In the first series of experiments, rigid thoracic and pelvic loading surfaces were separated by an “interplate gap” of 20.3 cm (8”). In the second series of experiments, the interplate gap was filled by a rigid plate mounted flush with the thoracic and pelvic loading surfaces. Impact velocities ranged from 7.2 to 15.0 m/s (about 15 to 30 mph). Injury patterns for the liver, spleen, and rib cage were significantly different in the two series of experiments (level of significance > 90%). The causative factor responsible for the different injury outcomes was the interplate gap. The conclusion of this report is that loading-surface discontinuities can cause significant injury. Therefore, in design of side doors and interiors, consideration should be given to the location of surface indentations (such as map pockets) as well as surface protuberances (such as armrests)."
The Importance of the Test Method in Determining the Effects of Door Padding in Side Impact,"This study examines the influence of padding in thorax side impact response under free-flight impact and velocity pulse impact. It was found that padding reduces rib and spine accelerations in both types of impact. However, in free-flight impact, padding reduces chest V and VC response without significant deformation change, while in velocity pulse impact, padding reduces chest V but substantially increases VC and deformation. It appears that free-flight impact lacks spacing effect and the correct velocity profile to simulate the door/occupant impact in car-to-car side collision. On the other hand, velocity pulse impact has the essential characteristics of the door/occupant impact in car-to-car side collision and is a more suitable method for subsystem test."
Corrosion Protection of Galvanized Steel Sheet - Corrosion Investigation of Field Vehicle and Its Laboratory Evaluation Methods,"For the accumulation of knowledge of perforation corrosion, three doors of three field vehicles made with one-side galvanized steel on the inside of the outer panels were investigated with some microscopic and analytical methods after 8 or 10 years’ field running in the snow-belt areas of North America. For these doors, perforations were found within the lapped part of the door hems. Outer panel perforation began as zinc layer corrosion of the inside surface of the outer panel at the lapped part and/or as “bent part” corrosion of the outer panel at the door hem. The inside of the outer panel lightly corroded at the open part in spite of the lack of primer on the inside surfaces of the outer and inner panels. The corrosion behavior of a lapped panel specimen test was studied and compared with that of investigated door hem corrosion. In the case of these doors, the test provided a result having a fairly good agreement with the field vehicle doors’ behavior."
Concept of a “Flexible” Combi Aircraft,"An airframe manufacturer is compelled to include the requirements of the air cargo transport market, existing and anticipated, in the definition of its products- A combi aircraft, derived from the passenger version, requires configuration flexibility. With the addition of an aft located main deck cargo door, six (6) 96 in × 125 in pallets may be carried on the main deck. All six (6) pallets can be loaded to a 96 in high contour, with both lateral upper corners cut. A number of other ULDs can be accommodated, e.g the AHA container, up to the 20 ft pallet. The flexibility to adapt to market requirements and i.e. airline route networks is achieved by the convertibility from the typical passenger layout with six (6) to five (5) to four (4) pallet combi configurations up to an all-passenger mode, with particular attention to conversion times."
“Optimization” of Lower Deck Cargo Systems,"The ability to carry cargo efficiently in passenger aircraft has influenced airline economics to the point that optimisation of the freight capacity is mandatory. This document discusses the alternative loading possibilities in defined Lover Deck Compartments and their doors to cater for current and future trends in ULD dimensions. As a result items for study centred on: 1) Optimisation of the available volumes Freight capacity resulting in the selection of “Pallets”-doors for both the Forward and AFT Compartments. Flexibility to meet Freight and Baggage requirements. Possible load arrangements to optimize aircraft C of G 2) Bulk Cargo Compartment Additional LD3 Container position in AFT/Bulk compartment to cater for an uneven number of Baggage container, allowing the carriage of an additional pallet. What is regarded as an optimum is presented."
Some Problems Concerning the Application of Sound Intensity Measurement to Automobile Noise Analysis,"Even if the sound intensity measurement (SIM), the most advanced sound measuring technique, has been used in the field of automobile noise control for over 6 years, there are still many technical problems pending for further research. Some of the problems involving the influence of sound source frequency features on the measuring accuracy of sound intensity (SI), application of SI map inside the automobile cab and the use of taperecorders are discussed in this paper and some useful results are presented."
Chassis Dynamometer Simulation of the Tractive Resistance of Vehicle,"This paper deduces a mathematical model to determine the road load force using coastdown techniques, and determines the model parameters using numerical integration by analysis in theory and verification in practice. On the basis of analysis and comparison of the vehicle load on the road and on a chassis dynamometer, it gives the relevant transformational relation, constitutes a set of new method of test and computation to determine the road load force by simple coastdown test and provides the foundation for vehicle performance test in doors."
Quieter rides,"SAE 100 Future look: Cell phones, high-end stereos, satellite radios, navigation systems, CD and DVD players. No it's not necessarily the inventory at your local consumer-electronics store. These are just some of the audio-related devices used in cars today, and surely these and others will be staples in the car of tomorrow. As a result, automobiles will have to become significantly quieter, keeping the noise out so passengers inside can enjoy the latest advances in communications and entertainment technologies."
Advances in Diesel Protection Systems,"Over the last several years, the use of D.C. solenoids and electronics to ensure safe and reliable diesel engine shutdown has grown significantly. These devices are used during normal engine operation and in the event of a malfunction. Applications include both on and off-highway vehicles as well as generator sets. The use of key start in off-highway equipment has also had a major impact on the use of D.C. solenoids. Reliability has been improved through the use of computerized coil design, constant volume protection boots, external switching and electronic timers. Testing methods (for vibration. shock and temperature extremes) have been developed to promote trouble free product life."
Numerical Simulation of Door Frame Deformation due to Aerodynamic Suction Force,Negative pressure around the front pillar of a vehicle travelling at high speed deforms the door frame in the outward direction. This causes the aspiration noise. Finding a method for the reduction of the resulting air aspiration noise is a goal of this study which analyzes this phenomenon. The method proposed here can be applied to find effective measures to reduce aspiration noise at the early stages of vehicle development.
Road Noise Reduction Using Transfer Function Synthesis Method,"An experimental simulation method has been developed for predicting the noise and vibration characteristics of a complete vehicle when body frame stiffness is changed. This method was developed by means of an improved transfer function synthesis method. Advantages over numerical simulation methods, such as finite element analysis include dramatic reductions in computation time. This experimental method is also very easy to carry out with a few measurement data. By applying this method to investigate the effects of stiffness changes of different vehicle components on low frequency road noise, effective ways of reducing road noise were proposed in the first stage of vehicle development."
Aeroacoustics Development at Pininfarina,"This paper reports recent developments made at Pininfarina in the aeroacoustic field with the aim of reducing the background noise in the test section of its full scale wind tunnel as well as for improving the measuring techniques which are used during the acoustic development of new cars. The first part of the paper describes the changes made to the wind tunnel drive-line, i.e. new motor, new low-noise fan and new acoustic treatments. The new background noise levels are reported and compared with the old values, already published in ref. (2). The second part describes the three acoustic techniques (acoustic intensimetry, acoustic holography and acoustic mirror) which have been developed or improved in the meantime, to measure the exterior noise of new cars from the first stage of their design. Examples of results of these measurements are reported as well as an indication of the capabilities and limitations of each technique."
Application of Derived Characteristics from Dynamic Test Data for Simulation of Car-to-Car Side Impacts Using a Lumped Mass Approach,"Lumped spring/mass modelling approaches are described for the simulation of structural and occupant response in side impacts (driver side). Special attention is placed on modelling techniques and procedures for mass assignments, derivation of force versus deflection characteristics and model redundancy checks. The force versus deflection characteristics were derived from dynamic test data and the inverse solution of the nonlinear equations of motion for the system. Unique procedures are also presented for estimating rib to spine damping characteristics and driver body segment internal and contact compliances. Three models are presented and evaluated. Simulations showing the effect of changes in striking car stiffness, struck car stiffness-, impact angle, impact speed, occupant to door clearance and interior door pad thickness and strength are presented and discussed. Model limitations and various factors affecting the applicability of the methodology are also discussed."
Vehicle Testing with Flat Surface Roadway Technology,MTS Systems has built and operated a vehicle test system called the Flat-Trac® Roadway Simulator. The system measures the handling characteristics of a running automobile while holding it stationary in a laboratory. The system can also test the vibration and durability characteristics of an automobile due to driving on rough roads by moving the surface beneath each tire vertically. The automobile is driven as on the road with the machine providing relative motion by moving a flat surface beneath each tire. This paper presents the results of operating a vehicle on the system with a rough road simulated during maneuvering.
Accelerometers Equivalency in Dummy Crash Testing,"The National Highway Traffic Safety Administration has initiated research to develop performance specifications for dummy-based accelerometers in the crash test environment, and to provide criteria for defining and establishing equivalent performance among accelerometers from different manufacturers. These research efforts are within the general guidelines on transducer equivalency outlined in the current revision of the Society of Automotive Engineers recommended practice, Instrumentation for Impact Test, SAE 211/2 March 1995. Representative data from vehicle crash and component level tests have been analyzed to determine the acceleration levels and frequency content in a realistic dynamic environment for dummy-based accelerometers. A series of component level tests (head drop calibration tests) and initial calibration tests (using a State-of-the Art commercially available comparison shock calibrator) were performed with a selection of accelerometers to determine dynamic response variability. A limited series of glazing tests is presented with discussion of the implications that high frequency accelerometer resonance response has on accelerometer selection and data acquisition practices. The results of these tests and recommendations for possible test procedures for evaluating accelerometer performance and equivalency in the crash test environment are presented."
The Future of Sunvisors,"A brief history of the sunvisor is laid in chronological order as well as the design of passenger cars with relation to shape and aerodynamic characteristics. A description of the slope of the windshield and the subsequent flattening of the roof line is also described and illustrated. The changing role of the visor is given in detail and describes today's visor and it's function and features. As the vehicle shape changes, so too, the visor and it's mission, of necessity, must accommodate this natural evolution. The role of the visor is shifting from that of sun blocker and feature support, to that of safety component. Described herein are the materials and processes that will be the future visor. Also, the end of the sunvisor as we know it is mentioned and how that will be accomplished. The main thrust of tomorrow's visor is impact management and safety for the occupants."
Research on the Evacuation Readiness of Bus Crews and Passengers - Investigation of the Effect of a New Type of Exit,"This research was conducted to propose appropriate emergency exits for bus crews and passengers. We developed the improved emergency exit based on the results of current bus exit performance tests, and investigated its effect on evacuation readiness. Tests employing human subjects were conducted to measure the time required to evacuate using the improved emergency exit. The subjects' psychological responses during evacuation were also studied to identify any evacuation problems. We also carried out tests of group evacuation through windows in a current bus to obtain the relationship between the evacuation time, the number of evacuation subjects, and the number of windows. The results show that the improved emergency exit is effective in improving evacuation readiness. It is clear that there is a positive correlation between the evacuation time, the number of subjects, and the number of windows."
Statistical Energy Analysis of Airborne and Structure-Borne Automobile Interior Noise,"This paper describes the application of Statistical Energy Analysis (SEA) and Experimental SEA (ESEA) to calculating the transmission of air-borne and structure-borne noise in a mid-sized sedan. SEA can be applied rapidly in the early stages of vehicle design where the degree of geometric detail is relatively low. It is well suited to the analysis of multiple paths of vibrational energy flow from multiple sources into the passenger compartment at mid to high frequencies. However, the application of SEA is made difficult by the geometry of the vehicle's subsystems and joints. Experience with current unibody vehicles leads to distinct modeling strategies for the various frequency ranges in which airborne or structure-borne noise predominates. The theory and application of ESEA to structure-borne noise is discussed. ESEA yields loss factors and input powers which are combined with an analytical SEA model to yield a single hybrid model. Results from model validation and correlation with measured data are presented."
The Creation of a Car Interior Noise Quality Index for the Evaluation of Rattle Phenomena,"Rattle noise produced in the vehicle interior due to broadband excitation by road irregularities is a major concern with respect to driving comfort, and therefore has become one of the most important topics of acoustic development in recent years. A quantification i.e. measurement of this rattle noise is of fundamental importance for systematic development work and production control. Common noise level measurements (dB, dBA, etc. ) do not represent the rattle character in the vehicle interior as revealed during initial investigations. To overcome this problem and to substitute the subjective assessment with a combination of measurable parameters, the psychoacoustic software AVL-EAR was applied to create an Interior Rattle Quality Index. Based on more than 40 different vehicles that have been subjectively assessed by approximately 70 test persons, the index was generated by means of multiple pair comparisons and statistics on measurement data. The index correlates appropriately with the subjective rattle impression, with correlation coefficients of about R = 0.88 for the individual vehicle categories."
Acoustic Performance Analysis of an Air Handling System,"In the present study, the acoustic performance of an automotive air handling system is analyzed using computational aeroacoustics methods. The purpose of this study is to develop a comprehensive method to quantify noise sources and predict sound quantities at any location in the system as well as in the exterior field. Flow of air and vibration of structures are solved simultaneously in the time domain. Results are then postprocessed to derive sound sources. Sound pressure levels at desired locations in the exterior field are then predicted. Predictions were compared with preliminary test data. Also compared is a simulation of the same system using a Helmholtz equation solver, but without taking into account the average fluid flow."
Experimental Body Panel Contribution Analysis for Road Induced Interior Noise of a Passenger Car,"This paper describes more in detail the methodology, the measurements and the results of the ASQ method. The Airborne Sound Quantification method aims at identifying the acoustical contribution of the different body panels surrounding a cavity. The contribution of different body panels is the product of the acoustical strength (or volume velocity) of each panel with the corresponding acoustic transfer function between the panel and the interior microphone position. These volume velocities are the product of the corresponding normal velocity and the surface. The normal velocity has been measured by means of accelerometers attached to the different subpanels. In the next step, the acoustical FRF's are measured in an indirect way using the reciprocity principle. This means that the pressure response at all the subpanels is measured when the acoustical excitation takes place at the target interior noise microphone position. A high quality low frequency sound source has been used. Finally, this synthesized interior noise has been compared with the directly measured interior noise. The correlation between both proved to be very good and the most dominant body panels have been successfully identified."
Determination of Vehicle Interior Sound Power Contribution Using Sound Intensity Measurement,"For vehicle interior noise abatement and noise treatment, it is desirable to quantitatively determine sound power contribution from each vehicle component because: (1) Sound packages can be designed with maximized efficiency if sound power contribution into a vehicle is known; (2) Acoustic leakage inside a vehicle can be determined by comparing sound power contributions from adjacent vehicle components; and (3) Sound power flow information can be used to verify Statistical Energy Analysis (SEA) model. Simple sound pressure measurement does not produce any information about sound power flow and is unsuitable for these purposes. This paper describes an in-situ determination of sound power contribution inside a vehicle using sound intensity measurements. Sound power contribution from each vehicle component was determined for engine noise at idle speed. Acoustic leakage in the vehicle was also determined. Practical considerations on the selections of measurement surface, measurement distance, and length of sound sampling time are presented. Sound intensity instrumentation and difficulties associated with near field sound intensity measurements are discussed."
Aeroacoustic and Acoustic Testing of Automobile Side Windows,"Several different automobile windows were tested for transmission of noise Bench-scale flow noise tests, full-scale wind tunnel flow noise tests, and acoustic tests were performed The windows tested were the front side windows of a Chrysler sedan The transmission of external airborne noise was measured in a hemianechoic chamber at the Chrysler Technical Center A loudspeaker was used as a white noise source The transmission of the white noise into the vehicle interior was measured Aeroacoustic or flow noise tests were performed in the Chrysler Wind Tunnel in Chelsea, Michigan The test car was placed in a 112 km/hour flow and the resulting flow-induced noise was measured in the vehicle interior Bench-scale flow noise tests were performed at the Cornell University Low Noise Wind Tunnel, using the same set of window constructions The paper describes the results of all three types of tests The bench-scale test data from the Cornell University Wind Tunnel correlated well with the corresponding data measured in the Chrysler wind tunnel"
Glazing for Motor Vehicles - 1995,"THERE ARE four viable types of glazing for use in motor vehicles: 1. Laminated 2. Tempered 3. Laminated glass-plastic 4. Tempered glass-plastic Laminated and laminated glass-plastic glazing will pass the MVSS Standard 205 for windshields, and all four types can now be used in side and rear windows. Laminated and to a limited extent laminated glass-plastic windshield glazing has been used in production, but the glass-plastic was not durable enough so it has been discontinued. Tempered glass has been used exclusively in side and rear windows since the early 1960's due to the strength requirements, and is the best choice for these locations. Recent experimental attempts to use tempered glass-plastic glazing in side windows have been unsuccessful due to high neck loads, and additional hazards in the designs. Even more important is the lack of durability due to more severe exposure than the glass-plastic windshield experienced."
A Structural Instrument Panel from Glass-Mat Thermoplastic for the Small-Car Market,"Designers and engineers encounter many challenges in developing vehicles for the small-car market. They face constant pressure to reduce both mass and cost while still producing vehicles that meet environmental and safety requirements. At the same time, today's discriminating consumers demand the highest quality in their vehicles. To accommodate these challenges, OEMs and suppliers are working together to improve all components and systems for the high-volume small-car market. An example of this cooperative effort is a project involving an integrated structural instrument panel (IP) designed to meet the specific needs of the small-car platform. Preliminary validation of the IP project, which uses a compression-molded, glass-mat-thermoplastic (GMT) composite and incorporates steel and magnesium, indicates it will significantly reduce part count, mass, assembly time, and overall cost. Investigation of the IP system by finite-element analysis (FEA) indicates the system demontrates the ability to pass Federal Motor Vehicle Safety Standard (FMVSS) 208 requirements for femur load and OEM requirements for noise, vibration, and harshness (NVH), while fulfilling consumer expectations. The concept-to-validation program, described in this paper, was undertaken by engineers and designers from two materials suppliers and one OEM organization to investigate the viability of the structural IP system."
Modeling of Airborne Tire Noise Transmission into Car Interior by Using the Vibro-acoustic Reciprocity and the Boundary Element Method,"In this paper, the vibro-acoustic transmission characteristics are investigated in the view point of the airborne noise in the interior cavity due to the tire wall vibrations. The analysis is carried out by categorizing the airborne noise transfer path into the two separate consecutive events. First, the noise transfer from the vibrating tire wall to the exterior car panels is modeled by using the direct boundary element method (BEM). To this end, after discretizing the whole geometry of exterior body panels, tires, and ground into BEM models, vibro-acoustic transfer characteristics are investigated at several frequency components associated with the cavity resonances of tire. Here, cavity resonance frequencies of tire are estimated by BEM and the distribution of tire wall vibrations excited by a special vibro-acoustic source is measured at those frequencies. Acoustic pressure distribution over the exterior car panels can thus be predicted and the contribution of local vibrational velocity of tire wall to car panels are estimated by the vectorial summation of resultant acoustic pressures. Second, vibro-acoustic transfer functions between the various points of car panels and the receiver's ear position in the car interior is measured by utilizing the vibro-acoustic reciprocity principle. Combining these two transmission path models in series, the airborne noise transmission from tire wall vibration to driver's ear can be analyzed. From the results, contributions of tire wall vibration to the interior noise can be estimated and the main possible transmission paths of airborne tire noise can be identified."
A CAE Methodology for Reducing Rattle in Structural Components,"Squeak and rattle has become a primary source of undesired noise in automobiles due to the continual diminishment of engine, power train and tire noise levels. This article presents a finite-element-based methodology for the improvement of rattle performance of vehicle components. For implementation purposes, it has been applied to study the rattle of a glove compartment latch and corner rubber bumpers. Results from the glove compartment study are summarized herein. Extensions to other rattle problems are also highlighted."
Computer Simulation of In-Vehicle Boom Noise,"In the design of an automobile, an important consideration is to minimize the amount of “boom” noise that the vehicle occupant could experience. Vehicles equipped with four cylinder engines can experience powertrain boom noise in the 40 to 200 Hz frequency range. Boom noise can also be generated by road input, and it is just as annoying. In this paper, a CAE methodology for predicting boom noise is demonstrated for a vehicle in the early design stage in which only 3-D CAD geometry exists. From the CAD geometry, a detailed finite element (FE) model is constructed. This FE model is then coupled with an acoustic model of the interior cavity. The coupled structural-acoustic model is used to predict acoustic response due to powertrain inputs. As a part of the detailed design process, various design modifications were considered and implemented in the vehicle system model. Many of these modifications proved successful at reducing the boom levels in the vehicle. A comparison of responses for baseline and modified designs will be shown. Comparisons will also be made to measured response from prototype and production vehicles."
Tire Noise Reduction Treatment for a Passenger Car Used as a Tow Vehicle for Pass-by Noise Testing,"The possibility of using a trailer to measure pass-by sound levels of tires has been limited by the tire noise generated by the tow vehicle. In order to verify the viability of the trailer method for passenger car tires, a trailer and tow vehicle were constructed and tested. A reduction goal of 3 dB(A) below the tow vehicle and trailer with the test tire was required for the tow vehicle alone. The noise reduction treatment, designed and developed for this project, successfully reduced the tow vehicle sound level enough to permit the coast-by trailer method to be used for tires as small as P145/80R13."
"Design, Construction and Application of a World Class Vehicle Acoustic Test Facility","The allowable noise emission of vehicles has been continuously reduced by legislation in the past. In parallel the interior noise level and noise quality have been improved dramatically. Even small size cars show today remarkable sound quality. This general effort to reduce vehicle noise has brought about a reduction in the combined effects of noise and vibration on the passengers. Today's vehicles exhibit more closely matched noise contributions from the engine, transmission, inlet and exhaust systems as well as road inputs via the suspension. For a further improvement of vehicle noise levels and sound quality, simple reduction of individual noise sources is no longer a suitable approach. A full understanding of their combined effect on vehicle noise is required, for cost-effective and production-feasible solutions to lead to the desired noise reduction or the achievement of a typical “Brand Sound” through sound engineering. For such development work, a vehicle acoustic test facility is absolutely indispensable. To qualify as a full partner in the Automotive Industry, AVL has established a vehicle test facility equipped with the very latest technology, capable of handling vehicles under all operating conditions. In this paper the vehicle acoustic test facility will be presented in detail, illustrating its use for noise reduction development activities ranging from reducing individual vehicle noise sources via trouble-shooting to sound engineering."
The Laboratory Simulation of Tyre Noise,A laboratory technique has been developed for simulating high frequency tyre noise in a car. The technique characterises air-borne tyre noise and its transmission from the tyre and road contact patch to the occupant positions. The technique could be applied to the rapid definition of design modifications in a laboratory environment and the generation of competitive criteria for vehicle benchmarking.
Noise Radiation from Axial Flow Fans,"A semi-empirical formula [1] for predicting noise spectra of an engine cooling fan assembly is developed. In deriving this formulation it is assumed that sound radiation from an axial flow fan is primarily due to fluctuating forces exerted on the fan blade surface. These fluctuating forces are correlated to the total lift force exerted on the fan blade, and is approximated by pressure pulses that decay both in space and time. The radiated acoustic pressure is then expressed in terms of superposition of contributions from these pressure pulses, and the corresponding line spectrum is obtained by taking a Fourier series expansion. To simulate the broad band sounds, a normal distribution-like shape function is designed which divides the frequency into consecutive bands centered at the blade passage frequency and its harmonics. The amplitude of this shape function at the center frequency is unity but decays exponentially. The decay rate decreases with an increase in the number of bands. Thus, at high frequencies the narrow bands merge to form a broad band-like spectrum. The noise spectra thus obtained are compared with measured ones from three different types of axial flow fans running under various conditions. The calculated total sound pressure levels from these fans are also compared with the measured ones and those obtained by using the fan laws."
Acoustic Optimization of HVAC Systems,"For HVAC systems this paper describes “excellent” acoustics and criteria and tools for acoustic evaluation. Focusing on the HVAC subsystem “air flow”, it further outlines four columns on which acoustic is based. Finally this paper discusses aspects how the vehicle design process which can facilitate acoustic optimization of HVAC systems."
Piezoelectric Actuator Configuration Optimization for Active Structural Acoustic Control in Aircraft,"This paper has presented a technique for the determination of an optimal configuration of fuselage mounted piezoelectric actuators for active structural acoustic control of interior noise in aircraft. The technique has demonstrated much potential in preliminary experiments where actuators were configured to couple into the first principal component of the acoustically coupled fuselage vibration. In this test, average reductions of 6 dB at the error microphones and 4 dB at five auxiliary microphones were observed for a pure tone disturbance at the left forward engine pylon of a business jet. This disturbance was used to simulate an oscillating force due to engine unbalance."
Correlation of Various Test Methodologies with Vehicle Seat Acoustical Performance,"Quietness is a primary metric of vehicle interior sound quality. Seats have always had the potential of enhancing interior quietness. An acoustic study was undertaken with seats to determine the similarity of result rank using different acoustic test methodologies. The component of test were seats for a production minivan. Nine complete seat sets underwent various acoustic tests. The nine seat sets were of various fabrics and construction. The acoustic tests were normal incidence sound absorption, random incidence sound absorption, in-vehicle sound absorption and artificial source noise reduction. A comparison of acoustical performance rank of seat sets from the various tests were obtained. Ranks obtained from various materials with in laboratory acoustical tests showed consistency."
An Assessment of the Tire Noise Generation and Sound Propagation Characteristics of an ISO 10844 Road Surface,"A road surface complying with the new International Standards Organization (ISO) specification was installed at an Arizona test facility (DPG site) in the winter of 1995/96. As part of the acoustic qualification of this site, comparative tests were conducted between this new surface, a Society of Automotive Engineers (SAE) sealed asphalt surface and an existing ISO surface in Michigan (MPG site). Initial testing with one vehicle and tire combination indicated that the new ISO surface produced ISO 362-1994 passby and coastby levels about 2 dB lower than sealed asphalt. Relative to the Michigan surface, the levels for the new Arizona ISO surface were 3 to 3½ dB lower. These differences were much greater than expected based on previously published studies of these two test surface types. Since the new surface was constructed to the ISO specification and meet the physical requirements for sound absorption coefficient, porosity, and surface texture, further investigation was conducted to determine if sound propagation or tire noise generation differences accounted for the differences. Experimental work to understand this difference included the use of on-board sound intensity measurements to isolate tire noise generation under both acceleration and coast and static sound propagation tests to isolate surface reflective properties. Analytically, a sound reflection model was developed to predict differences in attenuation based on measured surface impedance data. Taken together, the results of this investigation support the conclusion that a majority of the differences observed are due to tire noise generation. However, in comparing the new ISO surface to the SAE, a significant portion was also found to be attributable to sound propagation differences."
NVH Research Facilities at The Ohio State University: Existing Facilities and Envisioned Enhancements,"The automotive NVH research infrastructure at Ohio State includes the Center for Automotive Research, the Acoustics and Dynamics Laboratory, and the Gear Dynamics and Gear Noise Research Laboratory. This paper describes the facilities of these laboratories. Two unique existing facilities, namely the transmission error measurement of gears and a laboratory for the experimental measurement of engine breathing systems, will be emphasized. Also covered are the enhancements that are envisioned through a recent grant from the Ohio Board of Regents."
“Next Generation” Means for Detecting Squeaks and Rattles in Instrument Panels,"Engineers doing squeak and rattle testing of instrument panels (IP's) have successfully used large electrodynamic vibration systems to identify sources of squeaks and rattles (S&R's). Their successes led to demands to test more IP's, i.e., to increase throughput of IP's to reflect the many design, material, and/or manufacturing process changes that occur, and to do so at any stage of the development, production, or QA process. What is needed is a radically different and portable way to find S&R's in a fraction of the time and at lower capital cost without compromising S&R detection results."
Statistical Energy Analysis for Road Noise Simulation,"Statistical Energy Analysis (SEA) is being actively pursued in the automotive industry as a tool for vehicle high frequency noise and vibration analysis. A D-class passenger car SEA model has been developed for this purpose. This paper describes the development of load cases for the SEA model to simulate road noise on rumble road. Chassis roll test with rough shells was performed to simulate rumble road noise. Sound radiation from tire patch and vibration transmission through spindles were measured to construct the SEA load cases. Correlation between SEA model predictions and measured data was examined. Test and SEA result comparisons have shown that simulation of airborne road noise requires only a trimmed body SEA model, while simulation of structure-borne road noise may require SEA modeling of chassis components."
"Panel Contribution Study: Results, Correlation and Optimal Bead Pattern for Powertrain Noise Reduction","To understand how the passenger compartment cavity interacts with the surrounding panels (roof, windshield, dash panel, etc) a numerical panel contribution analysis was performed using FEA and BEA techniques. An experimental panel contribution analysis was conducted by Reiter Automotive Systems. Test results showed good correlation with the simulation results. After gaining some insight into panel contributions for power train noise, an attempt was made to introduce beads in panels to reduce vibration levels. A fully trimmed body structural-acoustic FEA model was used in this analysis. A network of massless beam elements was created in the model. This full structural-acoustic FEA model was then used to determine the optimal location for the beads, using the added beams as optimization variables."
Statistical Analysis of Vehicle High Mileage NVH Performance,"High mileage NVH performance is one of the major concerns in vehicle design for long term customer satisfaction. The current paper is concerned with performance analysis of high mileage vehicles which cover four automobile manufacturers and five vehicle families of the same weight class based on subjective evaluation data. The analysis includes the assessment of five vehicle families from the following aspects: overall and NVH performances, performance by individual attribute, degradation history of each vehicle family, performance variation within each vehicle family. Since the data are statistical in nature, statistical methods are employed, numerically and graphically, in the analysis. The performance categories which exhibit most degradation are identified. The analysis method presented in this paper is applicable to any high mileage vehicle fleet subjective data. The knowledge derived in the study can be used as a guideline in designing vehicles for high mileage NVH robustness."
An Engineering Approach to Sound Quality,"The subjective quality of sounds is a topic of increasing importance in the automotive industry. The first consideration is to describe the perceptual characteristics of this quality by means of jury tests or appropriate metrics. Once a NVH problem is determined in terms of an appropriate Sound Quality description, an in-depth analysis of the underlying physical phenomena must be made and engineering solutions newel to be proposed and validated This involves: • the detailed analysis of the signal structure in the time, frequency and order domain and identifying the signal Components Critical to the relevant sound quality dimension • the Correlation of the critical signal components to specific sources noise or vibration transmission paths and vibro-acoustic system characteristics. Ultimately this should lead to the prediction of the effect of feasible modifications in sound quality terms through the use of engineering models. This is up to now however only possible for a limited set of NVH problems due to limitations of Current modelling methods. The above procedure will be reviewed for a typical selection of sound quality cases. • a road noise problem (broad-band signal) • the sound of a door-slam (transient signal) Finally an overview of present research on the level of modelling for sound quality will be given; and the Collaborative EC project “SOQCRATES” on automotive sound quality engineering will be presented"
"FE Analysis, Dynamic Test and Correlation of Vehicle Structures","Computer simulation using finite element analysis techniques was used to predict and improve the performance of vehicle components and structures. In order to determine the actual loading and validate the FE model, extensive physical testing which involved data acquisition and analysis was undertaken. The paper shows the application of FE analysis and testing with examples for optimization of an automotive wheel, drive line vibration, car body shell interior acoustics and a railway vehicle structure."
"Acoustical Quality Control, Specifically Various Gear Wheels and Electrical Motors","The following describes a structure-borne noise measuring technology that is successful as an acoustical quality control for serial test. There are 2 examples for very efficient applications: 1.0 Already in 1981 the first full automatically working test decices have been installed. Since then more than 30 million step wheels for car gears were tested by this procedure. The rolling noise is judged by limit values with exact adjustable conditions. 2.0 The first “selfteaching”, computer-controlled electronics for electrical motors is working till today. Since 1985 the electrical and acoustical values of more than 10 million fans are tested automatically, whereby the tact rate per 2 fans amounts to 10 s."
Engineering Development and Performance of the Chrysler Dakota Fully-Integrated Thermoplastic Instrument Panel,"A fully-integrated thermoplastic structural instrument panel (IP) system will be implemented on Chrysler's Dodge Dakota Truck Platform. The structural IP consists of a three-piece monocoque thermoplastic injection molded structure that replaces the traditional retainer, air delivery ducts, steel beams and reinforcements typically used in IP designs. Ribbed thermoplastic bolster systems have been incorporated as part of the energy management system. The structural IP provides the required stiffness to satisfy noise, vibration, and harshness (NVH) quality targets and the necessary strength and rigidity to effectively meet FMVSS No. 208 requirements for managing occupant and passenger air bag (PAB) deployment loading during 48 km/h (30 mph) frontal crashes. This paper discusses the engineering development process and performance of the Dakota structural IP system as predicted by finite element simulations and the correlation of the predicted behavior through frontal barrier vehicle crashes."
Body Electronics Area Network (BEAN),"This paper describes the multiplex communication protocol, BEAN (Body Electronics Area Network), developed for body control system on passenger cars which in recent years has increased the scope of multiplex communication. BEAN is based on a protocol developed in 1992 (SAE920231) but expands upon the performance in areas, such as the suitability of the ID system for increase of ECUs, the variable data length enabling the transmission of diagnostic data, and the transmission rate, while keeping the cost and radiation noise level low. The software size of BEAN is compact enough to be implemented by general purpose 8bit MCUs which have recently seen improvements in performance. The BEAN communication devices are available corresponding to the scale of the application and configuration of the ECU taking into account the software capability. This protocol was evaluated using simulation with the body control system on luxury passenger cars."
"The General Purpose Work Station, A Spacious Microgravity Workbench","The General Purpose Work Station (GPWS) is a laboratory multi-use facility, as demonstrated during the Spacelab Life Sciences 1 (SLS-1) flight. The unit provided particulate containment under varying conditions, served as an effective work space for manipulating live animals, e.g., rats, served as a containment facility for fixatives, and was proposed for use to conduct in-flight maintenance during connector pin repair. The cabinet has a front door large enough to allow installation of a full-size microscope in-flight and is outfitted with a side window to allow delivery of items into the cabinet without exposure to the spacelab atmosphere. Additional support subsystems include inside cabinet mounting, surgical glove fine manipulations capability, and alternating or direct current power supply for experiment equipment, as will be demonstrated during Spacelab J. The GPWS, integrated and maintained in a double flight-rack, interfaces to spacelab systems including water cooling, avionics and cabin air, and power. Verification has been completed for multiple spacelab scenarios including SLS-2, SL-J, and SLS-3."
Mounting Systems for Plastic Glazing-Part 1-Component Level Testing,"This paper presents several mounting systems or installation techniques that can be used with plastic automotive glazing. The window designs are shown to be low cost, light weight, and meet several occupant headform safety goals. The designs employ double sided foam tape, or polyurethane windshield sealant and breakaway sections. The Side impact Dummy Hybrid III headform was impacted onto prototype windows at several head velocities to record Head Injury Criteria (HIC), laceration potential, and window retention characteristics. The HIC values for all the window designs are below the 1000 value set forth in FMVSS 208."
Headform Impact Testing of Plastic Glazing Materials,"The primary objective of this study was to compare the safety performance of two different plastic glazing materials to that of tempered glass in a moveable window application. A headform impact test method was used to determine if the use of plastic glazing materials offers the potential to reduce the risk of head injuries and fatalities inside impact collisions. These tests were conducted to simulate the dummy head velocity as it penetrates the side glazing area during Federal Motor Vehicle Safety Standard (FMVSS) 214 full-scale, side impact, crash testing. The two plastic glazing materials tested were an abrasion resistant (AR) coated copolymer of methyl methacrylate and N-methyl glutarimide (i.e., acrylic-imide or PMMI), and a polycarbonate (PC). Each of these window materials was evaluated in the driver's door of a Pontiac 6000 vehicle. The safety performance of these glazing materials was evaluated in each of the three categories: lacerations, head injuries due to contact, and containment. None of the materials tested resulted in lacerations which penetrated through the outer layer of chamois. This result indicates that each of the materials offered acceptable laceration characteristics. Head injury criteria (HIC) and 3 millisecond Clip values were used to assess the potential for head injuries due to contact forces. The highest HIC value measured was 262, which is much lower than the 1000 limit specified for FMVSS 208 frontal impacts. Additionally, the highest 3 ms Clip value measured was 55 g which is well below the 80 g limit specified for FMVSS 201. Therefore, the potential for head injuries due to contact is considered unlikely for each of the glazing materials. The test windows offered total containment at the following headform impact velocities: PMMI at 26 km/h (16 mph), PC at 17.5 km/h (11 mph), and tempered glass at 14 km/h (8.7 mph). The category of containment revealed the largest differentiation between these glazing materials and showed that PMMI offered total containment at much higher headform impact velocities compared to polycarbonate, followed by tempered glass."
Noise Problems Associated with Geometrically Stiffened Panels,"Although geometric stiffeners (ribs, beads, dimples, etc.) may initially appear to reduce the low frequency (<300 Hz) sound radiation capacity of otherwise flat panels, when sensitivity to treatment and automobile excitation mechanisms are considered, no significant acoustic or vibration benefits are apparent. Testing does reveal that stiffeners reduce the number of low frequency resonance modes, but add on vibration treatments are unavoidable since not all of the resonance modes can practically be raised to frequencies above primary engine excitation. Further, after even relatively Light treatments are added, flat panels exhibit lower Intuition might suggest that since increased panel stiffness can effectively reduce the overall surface velocities of untreated panels, add on treatments can be reduced and current sound levels will be maintained. However, this is not the case. Although initial reductions have been made, resulting in an initial decrease in sound radiation, evidence suggests that the sound radiation from a beaded panel (treated or untreated) is seldom as low as that from a treated flat panel."
Noise and Noise Reducing Materials,"Multilayer composites consist of viscoelastic polymers laminated between two metal “skins”. The polymeric core in the composite is subjected to shear, thus absorbing the incoming mechanical energy which is then dissipated as heat. This entire process acts to prevent generation of noise. These vibration damping composites are commercially more attractive because they can now be made by a continuous process in coil form rather than by the conventional, non-continuous laminating press procedure."
Structural-Acoustic Analysis for the Prediction of Vehicle Body Acoustic Sensitivities,"Body acoustic sensitivity, defined as the interior sound pressure due to a unit force applied to the body, has a major influence on the powertrain and road noise of a vehicle. Body acoustic sensitivity can be predicted analytically in the design stage of a vehicle program using structural-acoustic analysis. Recognition and correction of potential problems at this stage is a cost effective approach to improving a vehicle’s NVH performance. This paper describes the structural-acoustic analysis procedure. Techniques for developing the structural and acoustic models and coupling them to form a structural-acoustic system model are discussed. An application of the procedure for prediction and improvement of body acoustic sensitivity is given for a passenger vehicle."
Small Size Devices for Accurate Acoustical Measurements of Materials and Parts Used in Automobiles,"For sound absorption and sound transmission loss measurements, the existing international standards concern primarily building acoustics. The required measuring facilities are therefore very large and the corresponding surface areas of the samples are hardly comparable with the size of parts used in automobiles. Such measurements are, however, of great importance for development, comparison and optimization of sound proofing materials. Consequently, although a very large number of small size devices have been proposed which are ingenious and useful when taken separately, each one gives results which are different from the others. In this paper two devices will be presented. A small size reverberation room, which is a dimensional scale reduction 1:3 of a standardized room, is used for absorption measurements. A small emission room coupled with this small size reverberation room allows transmission loss measurements to be made. The surface area of the normal samples is 1.2 m2 for both devices and the results are comparable to those obtained according to the ISO Standards. With regard to the efforts being made to standardize methods which are well adapted to automobile acoustics, it is suggested that these two devices could be taken into consideration."
(Paint) Film Finishing in Practice,"(Paint) film as an alternative to spray applied paint has received growing attention in recent years. The potential for economic and environmental advantage and quality enhancement with this technology has been reported in several technical papers (Ref. 1, 3 and 4). The actual practice of film finishing, however, has received only limited notice. Film finishes have been applied to aluminum, stainless steel, PVC, and ABS. Starting in 1982, part applications include: wheel covers, door edge guards, window surrounds, roof drip moldings, lower windshield moldings, rocker panels, body side moldings, B pillars, and A pillars. Industry awareness and acceptance of film finishing as a viable alternative to spray applied paint is increasing. The two technologies are similar in many ways, yet distinctly different in other ways. They share a common goal: To yield a durable finish, economically and with superior visual impact. This paper reviews the unique aspects of film finishing."
Development of an Experimental Modal Synthesis Method for Coupled Acoustic-Structural Systems,"This paper describes an experimental modal synthesis method for determining the noise characteristics of coupled acoustic-structural systems. This method was developed to provide an essential tool for analyzing passenger compartment noise levels. With this method, it is possible to obtain the coupled acoustic-structural parameters directly from experimental measurements of noise and vibration. The resulting modal parameters provide the basis for predicting how structural modifications will affect interior noise characteristics. This paper presents the theory on which the method is based and gives examples of its application to passenger compartment noise analyses."
Application of a Generalised Frontal Crush Model of the Car Population to Pole and Narrow Object Impacts,This paper examines the deformation patterns of car fronts involved in both narrow object and offset frontal collisions and shows that the car side or sides not involved in direct crushing are pulled towards the centre of the car about a hinge point located 0.32 of the overall length to the rear of the front of the car. This corresponds with the location of the front of the car door/front bulkhead. The resulting crush profiles can be represented by simple geometric shapes. These are combined with a previously derived Specific Energy Absorption representation for the overall car population and applied to narrow object and pole impacts with car fronts. When compared with 19 staged pole impacts carried out by NHTSA high correlation is obtained and it is shown that the 95% confidence limits for calculated speed is +/- 9 km/hr.
Flexible SMC for Vertical Body Panels: Two Approaches for Success,"Sheet molding compound (SMC) has long been the composite material of choice for horizontal automotive body panels. The excellent surface, dimensional stability and stiffness have made it preferred for hoods, deck lids and roofs. Softer thermoplastic and thermosetting (RIM) materials have been considered for fenders and occasionally doors, i.e., vertical body panels. However recent work has shown some performance problems with these materials and automobile companies are examining the low profile SMC alternative. For fender applications increased flexibility over current horizontal body panel materials is desirable. Obtaining this flexibility can be readily achieved but usually at the expense of surface smoothness. This paper reports on work done to achieve a Class A flexible SMC system for compression molding. Markedly greater flexibility of molded parts has been achieved by new combinations of low profile additive and unsaturated polyester resin technology. Discussions of surface and flexibility testing will be presented."
Polymeric Reflective Materials: The Future of Body Ornamentation and Lighting,"Polymeric Reflective Materials (PRM) offer the automotive designer a unique new material and processing technology for vehicle ornamentation and lighting. PRM is a highly reflective multi-layer thermoplastic extruded sheet containing no metallization or surface coatings to create it's reflective appearance. PRM's ability to “transflect” light is a very unique characteristic. Transflection is the ability to simultaneously transmit and reflect light. PRM enables the integration of lighting components and exterior ornamentation to create uninterrupted exterior styling lines. PRM allows lighting components to disappear. Targeted applications include rear lighting lenses, illuminated body trim, emblems, door edge guards, safety lights, etc. Additionally, unique visual effects are created by front and second surface decorating. PRM also offers many interior styling options. The design concept is to have components appear bright metallic (silver, gold, copper, etc) and change appearance and or/color when back illuminated. PRM is formed and fabricated by conventional thermoforming methods. Conventional methods are utilized to trim formed PRM parts."
"A Single-Supply, Monolithic, MIL-STD-1553 Transceiver Implemented in BiCMOS Wafer Fabrication Technology","An integrated circuit has been designed for use as a single supply, MIL-STD-1553 transceiver using BiCMOS technology. Use of the BiCMOS fabrication process has advantages over both Bipolar and CMOS technologies. These advantages include: reduced standby current drain, increased flexibility in mating the transceiver to various remote terminals, increased control over output amplitude and rise/fall times, easier methods for adjusting filter response and residual voltage, and reduced chip size (over a CMOS transceiver). Development of this monolithic transceiver opens the door to future advances in remote terminal design. By combining the current driving capacity of Bipolar with the digital design capability of CMOS, the next probable step in the progression of MIL-STD-1553 technology would be a fully monolithic remote terminal. This device would combine a transceiver with the encoder/decoder and protocol logic on a single semiconductor device."
DNC/CNC Riveting Cells Applied in the International Aircraft Industry,"During the past decade, the number of implemented DNC/CNC Riveting and Assembly Systems has substantially increased and new applications have been introduced into areas where only manual or semi-automatic assembly was once considered. The main reason for developing these systems was the increasing demand for a better level of quality and higher production rates. This paper describes new upper tooling conceived as modular building blocks used on C-frame riveting machines. In addition, applications of C-frame riveting machines for the automatic assembly of pressure bulkheads and freight room-/passenger doors are discussed. Other applications described include the automatic floor grid assembly of large commercial aircraft."
Considerations for Plastic Abrasion Resistant Coated Windows for the Automotive Industry,"With the advent of today's abrasion resistance (AR) coating and plastic technologies, an alternative to glass glazing is now feasible. Automotive use of earlier forms of these products have pushed the research and development efforts of material suppliers and processors to the present state. Where this technology has been, how it has progressed, and what considerations are required for its utilization today will be discussed. The object of this paper is to define the design and processing characteristics required for the successful application of AR coated plastic, as a glazing material."
Development of a Practical DSP Car Audio System,"Digital signal processors (DSPs) are being used widely for sound field reproduction. However, it is difficult to apply a DSP to a car audio system because of the complicated acoustic characteristics of the passenger compartment. The authors have developed a new car audio system which employs special DSP software and a new speaker layout to provide excellent presence. The DSP has five output channels to generate stereophonic reflection from the front and rear speakers. The DSP software is programmed for each individual car model. A center speaker and A-pillar tweeters are used to produce a natural sound field in front through effective utilization of reflection from the windshield. This system is featured in 1992 Nissan models."
Cold Start Improvement by use of Latent Heat Stores,"Engine and cabin heating problems associated with cold starts at subzero conditions are greatly reduced by use of a Heat Battery. This is a latent heat store, collecting waste heat from the engine and storing it by use of efficient heat insulation. On the next cold start the heat is released with high initial power. The performance increases with colder environment conditions. Startability of the engine and the warm-up performance are improved. Emissions of hydrocarbons and carbonmonoxide are reduced up to 80 % in the CVS test at -7°C (20°F) and Diesel noise is lowered. The windshield is cleared of ice and frost and kept free of mist. Passenger comfort improves since hot air flows into the cabin within seconds after the Heat Battery is engaged."
Reconnaissance Capable F/A-18D Optical and Infrared Window Antifog Systems,"Aircraft modifications have been developed to make F/A-18D Hornets capable of being converted to a reconnaissance configuration which includes both optical and infrared sensors. A major design challenge was to prevent fog formation on the two exterior moldline windows used for viewing by these sensors. Antifogging was required during a rapid 7620 m/min (25,000 ft/min) descent into humid atmospheric conditions following a sustained cold soak at altitude. This paper describes the design development and laboratory verification testing of the two unique antifog systems selected to meet this requirement."
Enhanced Heat Transfer by a Spiral Spring Augmentive Device Inside a Round Tube,"The use of augmentive devices in round tubes to promote heat transfer has been known to the industry for some time. Early work has shown that the improvement in heat transfer in a round tube is considerably greater with an augmentive device when in the heating mode than in the cooling mode. As a result, the bulk of the effort, thus far, appears to be in the heating mode. This work is set to prove that the augmentive devices are as efficient in the cooling mode as in the heating mode. This work also opens the doors to many applications where space and cooling equipment size are a factors to be considered during the design of systems. This study utilizes a spiral spring augmentive device in four wire diameters and in four turns per inch for each wire diameter in a nominal 0.375 diameter copper tube. The coil diameter of the augmentive device was sized to fit inside the tube with a minimum clearance."
The Effects of Instrument Panel Top Color and Windshield Angle on Veiling Glare,"This Paper summarizes the results of research on the causes of windshield veiling glare in automotive vehicles. A special test apparatus was and built to simulate real-world windshield glare conditions. Four subjects were required to perform identification tasks under various levels of veiling glare. Error frequency and discomfort rating were used as the measurement of glare level. Results show the influence windshield glare from such parameters as solar brightness, solar position, windshield angle and instrument panel top color. Instrument panel color was evaluated using the Munsell attributes of Hue, Value, and Chroma."
A System Approach to Safe Winter Driving Considerations: The Visual System,"A systems approach is used to analyze the problem of providing optimum visual capabilities to deal with the demands required for safe driving in cold weather. Using a systems analysis approach, the problem is divided into its constituent parts (e.g. road conditions, vehicle features and design, the human components, etc.) and then these components, as they pertained to the defined visual system, are addressed.. Under temperate driving conditions, visual acuity and field of view are two of the most important considerations for safe driving. While these still remain important during winter driving conditions, windshield clarity and the problems associated with it, becomes extremely important. These three requirements have many related characteristics that may be overlooked when a systems approach is not used."
Vertical Body Panels: Flexible Class A Surface Composites Via Compression or Injection Molding,"Low Profile Class A sheet molding compound (SMC) is recognized as the composite material of choice for horizontal automotive body panels. The excellent surface, dimensional stability, stiffness and coefficient of thermal expansion have made it preferred for hoods, deck lids and roofs. softer thermoplastic and thermosetting (RIM) materials have been more considered for fenders and occasionally doors. recent studies have shown performance problems with these materials and SMC composites are being considered as an alternative. Increased flexibility over standard rigidity SMC is considered desirable for vertical body panels, particularly fenders. This flexibility can be achieved but normally at a major price in surface smoothness. This paper reports on research and development work done to achieve Class A surface flexible SMC/BMC composites that can be either compression or injection molded. these advancements have been made by a combination of shrinkage control agent (low profile additive) chemistry, unsaturated polyester structure, fiber wetting agent and fiberglass size technology. A comparison is made of surface characteristics, flexibility and physical properties which can be obtained via these two processing/molding techniques."
Improvements and Applications of Permanent Magnet Materials in Automotive Sensors,"Advancement of automotive electronic technology is leading to a greater use of permanent magnet materials. New vehicle specifications demand sensors and D.C. motors to be lighter and more efficient. Magnet manufacturers are developing materials and processes to meet these needs, both for the present and the future. Permanent magnets today are used in a wide range of industrial, domestic, automotive and aerospace applications. Their special, technological importance derives from their ability to act contactlessly on ferromagnetic material, either by attraction or repulsion, and to provide a permanent magnetic flux with no energy input and, hence, at no operating cost. The current usage of permanent magnets in domestic applications averages 50 per household in the United States, as illustrated in Figure 1. Perhaps the most surprising range of permanent magnet uses are the numerous applications in a modern passenger vehicle. These applications include an array of D.C. electric motors such as the starter, heater and air conditioner blower, windshield wiper, window lift, door lock and fuel pump motors. A fully equipped car can have more than 30 D.C. electric motors. Other uses include actuators, gauges and sensors, as shown in Figure 2. In all these examples, higher performance magnetic materials may afford the advantages of increased operating efficiency and reduction in size and weight. The continuing improvement in magnetic materials together with advances in power and integrated electronics has seen the development of a wide range of devices in which field coil windings are replaced by permanent magnets. These developments have also led to a dramatic increase in the use of permanent magnets in automotive sensor applications."
Automotive Testing Requirements in the Design of a Reverberation Chamber,"The purpose of this paper is to identify various concerns that need to be evaluated prior to the design and construction of a reverberation chamber, such that the chamber can be used for various automotive related acoustical measurements. Some of the concerns involve issues such as room shape and size, the degree of sound and vibration isolation required, the use of conventional building materials versus traditional massive construction, construction cost, and the performance requirements for the test noise generation system. Various uses of a reverberation chamber include random incidence sound absorption measurements, small sample sound transmission loss measurements, vehicle insertion loss tests, dash panel, door, and other “buck” evaluation tests, and sound power level measurements of small automotive components and devices. These uses have differing and in some cases conflicting requirements that compete in the selection of room design parameters. The paper discusses these issues including the requirements for sound level generation in the chamber for proper measurements. The paper also provides case studies on the use of reverberation chambers for automotive applications."
Acoustical Performance Testing of Automotive Weatherseals,"Advances in vehicle noise control are leading the automotive industry to place increasing emphasis on weatherseals to block exterior noise. As a result, properly evaluating the acoustical performance of automotive weatherseals is of increasing importance. There is no current specific standard for this testing. Rather, there has been reliance on adaptations of SAE Standard 51400 “Laboratory Measurement of the Airborne Sound Barrier Performance of Automotive Materials and Assemblies” by testing laboratories. However, the 51400 standard addresses testing of flatstock materials and does not readily lend application to pre-formed parts such as weatherseals. For this reason, adaptation of the standard can vary significantly from facility to facility and manufacturer to manufacturer. These differences can be significant and can render comparisons between test results on competing materials very difficult. This paper explores some of the limitations of using SAE J1400 to evaluate weatherseal performances and the likely impact of these limitations on test results. It also offers some considerations on developing a test procedure for an appropriate standard for evaluating weatherseals."
Automotive Squeak and Rattle Prevention,"Recent advances in automotive sound quality have reduced the general level of noise in the passenger compartment and focused more attention on irritating noises. Traditional methods of prevention and elimination of irritating noises such as squeaks and rattles are no longer sufficient to develop acceptable products in shortened product development cycles. Basic causes, design rules for prevention, and evaluation techniques using integrated digital data acquisition, laboratory simulation, acoustic and modal analysis techniques have been successfully developed to push the prevention process upstream in the development cycle."
Design of Automotive Audio Systems Using the Acoustic Transfer Function Measurement,"The small, irregular volume of the typical automotive cabin can induce large, unpredictable variations in the low frequency response (<200 Hz) of woofers in the audio system. Acoustic transfer function measurements of these effects, made using a reciprocity technique, show these variations at the listener's position. The response of a subwoofer design at any position in the vehicle can be predicted and optimized through computer aided convolution of the woofer response and the acoustic transfer function. A commercially available loudspeaker acoustic simulator, SPEAK, was used for woofer system design and simulation in an automobile."
"Engineering, Optimization, and Tuning of vehicle interior Sound Absorption and Other mechanisms for Sound Reduction","This paper treats the engineering, optimization and tuning of vehicle sound absorption with emphasis on headliners. It covers the methodology of measuring sound. The mechanisms for sound reduction damping are discussed. The report compares the acoustical performance of worldwide headliner constructions at different frequencies and leaves it up to the reader to make his/her own evaluation. The Authors discuss means to enhance and optimize and tune headliners to increase the acoustic functionality of the parts. The paper also shows the relative acoustic performance of interior trim parts. Future trends and methodology are explored along with the European trend to eliminate roof bows and the headliner being robotically adhered to the roof to improve acoustics, structural effectiveness and lower cost."
Vehicle Drive Line Dynamic Behaviour Simulation,"A mathematical model was built up and a computer programme was developped in order to simulate the drive line of a vehicle. Particular attention was given to the possibility to incorporate non linearities such as teeth clearence and torsional stiffness of the clutch plate. With the model it is possible to study rattling and hammering of the gearbox and in particular the influence of the clutch on it. Also the influence of a vibration absorber on resonance frequencies is investigated. Due to a extrapolation of the programme, we are also able to analyse the interaction between the torsional stiffness of the driveline and the axle vibration on his suspension."
"The Application of Bonded Aluminum Sandwich Construction Technology to Achieve a Lightweight, Low Cost Automotive Structure","Bonded Aluminum Sandwich Construction Technology offers a new approach for automotive manufacturers to rapidly develop low volume niche products that achieve world class results for weight, cost, styling and surface finish with minimal tooling investment. Using sandwich panel construction in the development of their new ultra lightweight sleeper, Western Star Trucks was able to reduce the product weight by 50%, manufacturing costs by 25%, and tooling and development cost by 75%, while significantly reducing development time. In less than one year the company was able to deliver a new family of Star Light Sleepers that replaced a conventional stamped steel body-in-white structure with the same basic body shape but with improved styling detail and surface finish. Additional benefits encountered included increased ease of assembly and interior finishing, and improved reparability and noise and thermal attenuation."
Aeroacoustics of an Automobile A-Pillar Rain Gutter: Computational and Experimental Study,"Noise due to the flow over an automobile A-pillar rain gutter in isolation was computed using a two step procedure. Initially the flow solution was obtained by solving the Reynolds Averaged Navier Stokes (RANS) equations. Acoustical Sources were extracted from the flow solution and propagated to the far-field using the Lighthill-Curle equation. Experiments were conducted to evaluate the computations. Compared results include steady pressures, time dependent pressures, and sound intensity levels. Computed results and experimental data were reduced in a similar way to ensure a one to one comparison. Computed results are in good agreement with the experimental values. A-weighted noise levels are predicted reasonably well."
Booming Noise Analysis Method Based On Acoustic Excitation Test,"A method for analyzing and decreasing booming noise in the cabin of a minivan using acoustic excitation tests has been developed. To ensure a pleasant ride for passengers of minivans equipped with four-cylinder engines, decreasing cabin noise from secondary components of engine revolution has become a priority. “Booming noise” in the cabin originates from engine vibration that passes through engine mounts to shake the body structure and body panels. To decrease the level of sound pressure resulting from this shaking, one effective approach is to reduce the level of the mechanical-acoustical transfer function (MATF) in the interval from engine mounts to passengers' ears. This paper reports on a specific method for reducing the level of MATF. In this method, a speaker is positioned near a passenger's ear to measure the vibration-response level at the points where engine mounts are installed when exciting the body structure, and the level is reduced by modifying the body structure. This method makes use of the relationship between MATF and vibration response during acoustic excitation, which can be considered equivalent according to the reciprocity principle. The following conclusions were reached when applying this method to decreasing 60- to 120-Hz booming noise in minivans that mount the engine under the driver's seat. The pattern of vibration distribution measured when exciting body structure by a shaker is generally different from that measured by acoustic excitation, and the proposed method that modifies body structure to suppress the latter vibration can improve MATF levels in a relatively short time. In other words, when exciting body structure by a shaker or when running the vehicle, the vibration components of body structure that excite the cabin resonance mode and generate booming noise are normally hidden by vibration components that do not result in sound."
Four Legs in the Morning: Issues in Crew-Quarter Design for Long-Duration Space Facilities,"In designing habitats for long-duration space missions, one of the primary issues to address is that of sleep spaces, commonly known as Crew Quarters. While ergonomic design plays a major role in short-duration crew quarters (CQ) design, longer term missions must take into account the significant effect which environmental factors have on crew productivity; to that end, the establishment of private space for each individual crew member, as well as a range of semiprivate work and rest areas represents a significant departure from established norms in space habitat design. Both for proposed planetary habitats and microgravity habitats, various systems must be studied to enhance the wellbeing of the crewmembers. Improved lighting, color, and acoustic environments as well as the introduction of diurnal simulation systems, virtual windows, flexible partitions and other potential innovations are being investigated by the Space Habitation Design Group as means of developing efficient, high-acceptability crew accommodations."
Everyday Noise - All Day,"In the Lunar-Mars Life Support Test Project chamber, crewmembers collected various sound level measures starting with the entry day ceremonies and ending with the welcome home celebrations. Crewmembers recorded sample decibel(A) levels in the 80s and 70s in the mechanical area; 70s and 60s in the common living and work areas; and 50s and 40s in the individual crew quarters. Medical personnel evaluated crewmembers for threshold hearing shifts comparing audiometry readings before and after the chamber experience. The discussion relates the chamber findings to the operational requirements for space stations and planetary habitation, as well as for long duration exposures on Earth."
Aeroacoustic Testing Improvements at Pininfarina,"Aeroacoustics is playing an increasing role in the development of new passenger cars. However, most existing wind tunnels, with few recent exceptions, have been designed and built with little or no attention to their aeroacoustic aspects. Building new wind tunnels with excellent low noise levels is technically feasible today, however it is not often justifiable from an economic standpoint. In the case of the Pininfarina wind tunnel, built in 1972 without any specific noise target, a decision was taken in 1984 to progressively upgrade the facility and the acoustic measuring techniques. A target of reaching a background noise level low enough to allow satisfactory acoustic development work on new cars, with the contemporary use of more modern measuring techniques, was established. This decision implicitly assumed that, to do this development work, it is not necessary to reach the very low noise levels of a pure acoustic wind tunnel. The paper reports a short description of the main modifications made to the facility, in the years 1985-90, and the main results obtained. Then, it describes some of the new measuring techniques which have been set up in the meantime. They are optimized so as to be as efficient as possible in the presence of the background noise. This noise has a relatively low level and a favorable spectrum when compared with other aerodynamic wind tunnels, but this noise still remains worse than that of the acoustic wind tunnels. In order to further improve the existing situation, a new three-year research program has been recently started (mid 1992). Its main aim is to improve the capability of detecting the noise sources on the outer surfaces of cars. To do that, new measuring techniques are in course of development and testing. At the same time, further modifications to the facility are going to be carried out, mainly to its fan-drive system, to reduce the background noise level. An overview of this new research program is reported in the second part of the paper, together with some examples of the latest experimental results."
Measurement and Prediction of the Sound Transmission Loss of Automotive Glazing Materials,"The transmission of sound through automotive glazing materials was investigated. The sound transmission loss in one-third octave bands of several different automobile windows was measured at a testing laboratory. The materials tested included monolithic (single-layer) glass, monolithic polycarbonate, and a double glazing with an air gap in between the two panes. The experimental data are given in the paper. Subsequently, a computer spreadsheet program was written and developed to predict the sound transmission loss of single-layer glazing materials, using empirical equations found in the literature. The predicted sound transmission loss values showed good agreement with the experimental values. The sound transmission loss spreadsheet is a useful, easy-to-use tool to predict the acoustic performance of automobile window glazing materials."
Multilayer Laminated Composites for Noise and Thermal Control - PRE FINISH METALS,"Continuous developments in car design and customer attention to performance and comfort have created necessities for improvements in external and internal noise reduction in cars, trucks and busses and thermal control around engine and exhaust areas. Solutions to these “challenges” are usually combinations of novel designs and selection of more efficient engineering materials. The authors describe the development of laminated composites consisting of outer metal “skins” with a specially selected core material between them. Depending on the noise damping and/or thermal insulation properties required by the application, the core materials may be viscoelastic polymers or inorganic materials.. As the result of this development, “families” of different materials for such applications are presented with the description of material properties and potential uses. These material systems include composites for noise reduction of parts in engine compartment, body parts, brakes, and materials for thermal control in under-the-hood, exhaust, and catalytic converter applications."
In-Car Early Reflection Studies Using In-the-Ear Microphone Techniques,"After prototyping numerous sound systems for automobiles, it is often frustrating for the design engineer to gather a number of listeners and each turns out to have their own perception of the system performance. Some people are sensitive to localization problems in the car yet are unaware of reflection induced frequency response problems. The converse holds true for other listeners that notice small anomalies in frequency but are oblivious to localization difficulties. A trained listener can often balance the frequency and imaging issues though by tilting their head or mentally biasing the acoustical data. The reasons for these differences in listeners is often due to the pinna, which is the visible part of the outer ear. In-The-Ear™ microphones, recently developed by Etymotic Research [1], are placed in the ear canals of several listeners to measure these influences in hope of understanding why these contrasting opinions exist."
Experimental Investigaton of Radio Antenna Wind Noise,"Recent advances in the field of vehicle noise control have subjected the automobile to the “drained swamp syndrome”. Quieter engines, powertrains and bodies, combined with passive sound treatments for the interior have unearthed the stumps; radio antenna wind noise is one of them. This has prompted various innovative designs and redesigns for radio antennas that have been employed by major manufacturers in recent vehicles. This paper aims to determine the optimal antenna design through experimental testing both on the road and in the laboratory."
Engine Sound Quality in Sub-Compact Economy Vehicles: A Comparative Case Study,"A comparative study was undertaken to investigate engine noise in sub-compact vehicles under typical highway operating conditions. Baseline acoustical testing was performed. Typical sound quality metrics indicated that passenger cabin noise levels and sound quality were similar among all vehicles tested. However, poorer subjective sound quality in a vehicle equipped with a 3-speed automatic transmission was related to a higher degree of perceived periodicity than in other models. Further study of the 3-speed vehicle indicated that installing a 4-speed transmission would reduce noise more effectively than any substantial changes to the vehicle structure or engine mounting system. Damping or barrier treatments applied to the firewall or toe pan did not provide significant benefit."
Design and Test of Voice Interfaces in Cars,Voice interfaces are of much interest for car designers: they are a safe way to operate various devices. However car compartments are very hostile environments for voice capture and emission because road noise is very loud. For every new car much time must be spent on their optimization which involves tools for quality evaluation. Comparing configurations is not practical while driving. A simple model of voice interfaces based on impulse responses makes reliable tests much easier to implement. This paper describes its practical application and shows a few objective results.
Effects of On-Road Turbulence on Automotive Wind Noise: Comparing Wind-Tunnel and On-Road Tests,"For high-speed driving conditions, the air flow around a car creates wind noise that is transmitted into the cabin, which can dominate other noises. If an atmospheric wind is present, it will create a turbulent cross wind, which not only changes the air flow velocity and direction as experienced by the vehicle, but leads to continuously varying wind noise, as heard inside the car. The purpose of this paper is to look at how the on-road wind environment affects wind noise, and to evaluate the need to simulate real on-road conditions such as fluctuating yaw angles and velocities in vehicle wind tunnels."
Assessment of Air Bag Module Durability Test Specifications Using CAE Techniques,"Several air bag module vibration testing issues are identified. Eight OEM air bag module vibration test specifications are compared in terms of predicted fatigue lives using computer simulation. The specifications differ significantly in the type of loading (sine sweep, fixed sine and random), frequency range, and test duration. The comparison results indicate large variation in the relative severity of specifications based on the computed fatigue lives. This variation indicates that a more standardized approach for deriving representative vibration test specifications is desirable. The unrepresentative specifications can lead to overdesigned components, diminishing the value of the air bag system. Experimental results used to validate the analytical predictions are presented along with the simulation results. A computer program developed to perform the fatigue life calculations for both sine sweep and random vibrations is also described. Several suggestions for developing representative specifications are provided."
Importance of Sealants for Interior Noise Control of Automobiles,"Sealant materials are used in todays automobiles for many applications such as, sealing of body seams, sealing access holes and the filling of hollow cavities. The primary reasons for these applications are to prevent corrosion, prevent water intrusion, and to reduce the noise level in the passenger compartment. However, the noise control capabilities of sealant materials have not been explored until recently. This paper discusses the requirements that a noise control material must possess, and reviews how a sealant material can fulfil these requirements. Properly designed sealant materials can possess sound transmission loss (barrier) properties, vibration damping properties over a given frequency and temperature range of interest, and often sound absorption properties with proper formulation. This paper provides case studies to substantiate the acoustical capabilities of sealant materials."
Automotive Rollover Angular Rate Sensors and Evaluation,"This paper presents a test methodology for evaluating angular rate sensors used for detecting vehicle rollover. The key electrical parameters over temperature are tested with a rate table. Immunity to linear accelerations is evaluated at room temperature with a vibration table and a thruster. The vibration test provides mechanical resonance information and rough road performance, while the thruster test provides g-sensitivity parameters under severe impact conditions such as with vehicle frontal and side impact events. The vehicle level evaluation includes severe vehicle maneuvers, rough road and gravel road tests, as well as full-scale vehicle rollover tests."
Vehicle Passenger Door Hinge Systems,The scope of this SAE Recommended Practice is to establish recommended uniform test procedures and minimum static load requirements for vehicle passenger door hinge systems. Tests are described that can be conducted on test fixtures and equipment in laboratory test facilities. The test procedures and minimum performance requirements outlined in this recommended practice are based on currently available engineering data. It is intended that all portions of the recommended practice be periodically reviewed and revised as additional knowledge regarding vehicle hinge system performance under impact conditions is developed.
Application of Formable and Self-Skinning Polyurethane Foams in Headliners,"The initial function of headliners in automobiles was to conceal the rough appearance of the exposed roof construction. As the roof construction evolved towards solid metal, the requirements for headliners grew to include acoustic and styling properties. Today, fiberglass-based headliners have the major share of the North American market in high and mid-line vehicles. However, there is a recent trend to find substitutes for fiberglass headliners because of their skin irritation effects on assembly workers. Headliners based on formable and self-skinning polyurethane foam have gained wide acceptance in Europe as an alternative to fiberglass. This paper discusses the different PUR processes involved and the characteristics of the finished headliners produced with these PUR foams."
"Simple, Passive, Non-Contact Class A Multiplexing Method Using Programmable Surface Acoustic Wave Devices","This paper describes a novel technique for class A sensor-to-module multiplexing using surface acoustic wave (SAW) technology. This technique converts information on the status of N switches to a series of N pulses in the time domain. The basic enabling technology is a programmable SAW reflector, which may be programmed to either a nonreflecting or partially reflecting state by closing or opening a switch connected to the reflector. The SAW device consists of a transducer and N programmable reflectors printed on a piezoelectric substrate such as lithium niobate. To read the status of the switches, an electronic module sends an interrogating rf pulse to the transducer. At a series of later times determined by the spacing of the reflectors from the transducer and the SAW velocity, return pulses are generated whose amplitudes are determined by the corresponding switch settings. Coupling between the electronic module and SAW device utilizes a pair of coupling coils. This allows the status of switches on a rotating or moving object such as a steering wheel, tire, or door, to be read without making any electrical contact to the moving object. Only the switches, the SAW device, and a coil, all passive components, need to mounted on the moving object. A system to read 15 switches on a steering hub has been developed utilizing a simple SAW device and low-cost electronics, and it is straightforward to extend the system to a higher number of switches."
Use of Continuously Annealed Bake Hardenable Steels for Automobile Outer Panels,"The automotive industry's ongoing effort to improve quality and reduce weight without added cost has led to the investigation of many medium strength steels. This study presents a comparison of continuously annealed Bake Hardenable Steels (BHS) with current DQSK production materials for outer panel applications. While all steels exhibit strength increases from work hardening during forming, BHS has a unique and ideal characteristic which produces an increase in yield strength due to strain aging during the paint baking process at the automotive assembly plants. This results in an increase in dent resistance. BHS is a desirable material for relatively flat outer panels which often receive only small strains during forming such as in doors, hoods and decklids. Improved durability against dents, dings, and palm printing are obtained in the BHS parts. Similarly, quality improvements are realized in the stamping and assembly plants by a decrease in handling and transit damage."
A Multilayer Membrane-Tension Automotive Door-Barrier System,"An alternative device based on the membrane-tension principle was developed to improve the resistance of vehicle doors to side impact. The device is comprised of several layers of sheets. The outermost layer is essentially flat and the other layers are corrugated, each with the same pitch but with a successively greater depth. The ends of each layer are attached to tabs which are connected to the door frame in a manner suitable for developing the required forces. In this concept, the side impact pushes inward on the outer sheet and causes it to develop membrane tension because its axial movement is restrained at its ends. As the inward intrusion increases, the outer sheet stretches inelastically and eventually ruptures. This action continues as successive sheet layers are stretched to rupture. The computer program, DOOR1, was developed to aid in designing the device to suit various geometries and packaging criteria. Tests were conducted on prototype specimens and compared to a companion test of an existing system. The tests indicated that the new door barrier device acting alone can deform up to 18 inches and reach a maximum load of at least 11,000 pounds in a typical three-layer, 46-1/2-inch span configuration. Details can be selected so that the load-deformation curve can be engineered to provide a desired shape. Because it appears that the new device could potentially improve crash resistance, full-scale tests on a vehicle are planned."
Characteristics of Box-Annealed Bake-Hardenable Steels,"Bake-hardenable steel optimizes the combination of higher formability (low strength and high ductility) needed for part formation and higher final strength needed for dent resistance in the finished part. In outer panel design, it is important to understand the bake-hardening mechanism and its relationship to strain states in the part, bake temperatures and time. Bake-hardening steel exhibits carbon strain-aging that significantly increases the material's strength after part formation. The aging mechanism is created in box-anneal sheet product by the control of annealing parameters and heat composition. Property data from bake-hardenable material currently being used on a door outer application is discussed. Two different aging studies show the relationships between bake hardenability and the variables of strain, baking temperature and baking time. A third study demonsrates that, once strain is induced, strain-age hardening begins to occur at room temperature."
Soft and Light Door Trim by Using Double Slushed Skin and Glass Mat Reinforced Rigid Polyurethane Foam Core,"As for recent market needs, there is an increasing demand for the total coordination of the vehicles interior trims, the enhancement of adaptability for freer designs, soft touch and weight reduction. In order to meet these demands, we have developed a door trim reflecting this new concept. This door trim is manufactured by foaming rigid polyurethane foam as the core material after the double slush skin (1st layer: PVC, 2nd layer: PVC foam) and the glass mat are set together in the foaming mold. Employment of double slushed skin allows an improvement in flexibility of design, softer materials to be manufactured and further coordination of color, gloss and grain pattern with those of instrument pad. In addition, we have succeeded in reducing the weight by using glass mat reinforced rigid polyurethane foam. Since the center ornament fabric is formed together with the skin, the look at the joint section of the fabric and skin has been improved remarkably compared to conventional products. We also succeeded in reducing the number of processes by abolishing the ornament assembly process and by improvement in the treatment of periphery and terminal of parts."
Turnkey Processes for Window Encapsulation,"As window encapsulation technology advances, the requirement for process improvements to decrease cycle time, improve part quantity, and to minimize labor requirements becomes very important to the manufacturers. Traditional module systems have advanced to include closed-loop control metering units; fast acting, reliable presses; and SPC data collection systems. Turnkey automatic systems include robotic load/unloading, centering station, automatic/semi-automatic priming station, and robotic IMC/mold release. The demands to reduce overall costs has led manufacturers to consider several alternatives that prove best for their application. This paper is to list and expand on these alternative solutions."
Passive Venting for Alleviating Helicopter Tail-Boom Loads,"The tail boom of a single-rotor helicopter is subjected to a complex flow field that includes the wakes of the main and tail rotors, the freestream, and the wake from the forward fuselage. Hovering and sideward flight present the operational regimes that are most critical with respect to adverse sideward and downward loads on the tail boom. These adverse loads necessitate additional engine power, thereby reducing payload, performance, and available yaw-control margins. In addition, nonlinear side-force gradients near conditions of boom stall can make precise yaw control very difficult for the pilot. The addition of strakes to the tail boom is one method that has been used to modify the flow field and reduce these adverse loads."
A Flexible Lateral Seam Riveting System for Circular Aircraft Structures,"The need for a flexible and automated seam riveting system has opened the door for a new approach to machine design. The Flexible Lateral Seam Riveting system (FLSR) proposed by Gemcor will be able to automatically, under CNC and tracer control, rivet both lateral and radial joints without the use of dedicated and fixed machine track systems. The FLSR system is adaptable to a wide range of part diameters and configurations with lengths up to 10m (394 inches). Applications include aircraft fuselage sections as well as any other circular section which is assembled with rivets or other standard aerospace fastener systems including interference fit type."
Study on Test and Product Variations of Noise Reduction Capabilities of Headliners,"This paper discusses the importance of studying different variabilities (test and product variations) that may affect the noise reduction capabilities of automotive headliners, constructed from different materials. For this purpose, interior noise measurements were made at a position approximating the operator ear level, with different headliner materials under various operating conditions. For better understanding of the effect of different variabilities on acoustical performance, various single number values were computed from the measured data reduced in 1/3 octave band frequencies. Statistical data analyses show that the acoustical performance evaluation of headliners is affected by the product variation from one headliner to another, as well as experimental variation due to vehicle performance and test variation."
A Mathematical Model for Calculating the Dent Initiation Loads at the Door Centers,"A computational procedure is presented to evaluate the static dent resistance at the center of a steel door panel. Using the design parameters of geometric shape, thickness and the stress-strain relations of the steel, the static dent initiation load can be calculated. The method is based on the concept of plastic work which is the non-recoverable energy dissipated in the panel by the applied load. A threshold value of plastic work of 0.02 joule is used to signal the dent initiation. A comparison of the computed and measured dent initiation loads of ten experimental panels shows the maximum deviation is less than 20 newtons."
Automobile Aerodynamic Noise,"As engine, tire, and other automobile noise is reduced and as driving speeds increase, aerodynamic noise sources on ground vehicles are becoming relatively more important. They often dominate at cruise speeds above 60 mph. Aspiration and leak noise are strong sources but generally can be controlled by known methods. Turbulent pressure fluctuations due to separated and vortical flows are also strong sources. Much interior noise is caused by transmission of these external pressure fluctuations through windows and other surfaces. The paper presents the variety of aeroacoustic sources on automobiles and reviews the state of experimental data, of analysis methods, and noise reduction principles. A new correlation method for predicting external fluctuating pressures in separated regions is presented."
Built-In Speaker Car Sound System,"The acoustic characteristics of the sound field inside a vehicle cabin were analyzed. On the basis of the analysis results, a three-way horn speaker system for vehicles was developed, comprising a woofer, a mid-range, and a tweeter. For a woofer, we developed a speaker system utilizing resonation of acoustic tubes, in which the acoustic tubes provide acoustic impedance well matched to the acoustic impedance of a vehicle cabin space. In this paper, to identify the influence of standing waves inside a vehicle cabin, we evaluate the sound field reactivity in terms between sound field reactivity and sound image localization or the frequency characteristics. For a mid-range, we developed a speaker system with its directivity controlled by a sound source with a rectangular shape, thereby realizing a well-diffused sound field even in a restricted narrow cavity providing us with the tendency of an expanding sound image. For comparison with the conventional speaker system, data including the accumulative power characteristics and binaural correlation characteristics of this speaker system are presented in this paper. For a tweeter, we developed a system which combines a directivity controlled multi-horn speaker and a digital filter, thus realizing an improved asymmetric sound field and definite sound image localization. For this development, we analyzed the sound field inside a vehicle cabin using the acoustic ray tracing method, and the wave front in the horns by the finite element method. With the above systems, a car audio system has been realized which permits definite sound image localization just in front of a listener, and stereophonic balanced sound reproduction for both the driver's and passenger's seats, for all frequency ranges."
Combining Materials and Functions for Low Cost Manufacturing of Headliners,"Headliners are large parts that must be lightweight, sound absorbent and sturdy enough to carry a complement of other interior components as well. And as the dashboard becomes loaded with more and more technologies, there is a drive to spread some of that complexity over the rest of the interior of the car. Automotive headliners offer an opportunity for slashing vehicle production costs by integrating components and functions in a one-step operation. The headliner is the ideal candidate not only to accept sun visors, lighting systems and hand grips, but also garage door openers, cellular telephones and audio speakers. This paper will discuss the use of low pressure injection molding as a way to reduce headliner production costs while expanding functionality. It will also examine the equipment requirements and the implications of this process for designers and manufacturers of vehicle headliners."
Agricultural Cab Operator Comfort,"Modern agricultural machines are very complex, requiring extensive monitoring of multiple operations at the same time as they travel over very rough terrain. Hence, the cabs must be designed to provide not only good visibility of all monitors and easy access to all controls, but operator comfort and safety as well. This includes climate control (temperature, humidity, dust, noise, etc.), vibration damping, easy access on to and off of the tractor, good visibility from the cab and no controls jutting out where they could constitute a hazard. Good cab design promotes efficiency, comfort and safety."
Gantry 5 Axis DNC/CNC High Speed Milling and Drilling Machine with Integrated Multiflexible Universal Holding Fixture for the Aerospace Industry,"An airplane fuselage structure basically consists of many individual fuselage panels which differ considerably in size and shape. Each individual panel is automatically assembled from individual components, such as the panels, frames, stringers, clips, shear ties, window frames, etc."
The Modern Chassis Dynamometer as a Testing Device in the Acoustic Laboratory,"Development work for the reduction of vehicle noise Is mostly performed in laboratories. The paper describes testing equipment of the latest state of the art that is used in a laboratory for vehicle acoustics. The test specimen and testing equipment are installed in an acoustic chamber. All design measures for noise reduction will be described. The equipment for noise measurement and analysis is included in the chassis dynamometer control and automation system. Noises and vibrations are picked up by special measuring devices and analysed in a separate computer, which is linked to the test stand computer. The results of measurement will be presented and explained."
Recycling Polyurethanes - An Industry Update from the Polyurethanes Recycle and Recovery Counsel (PURRC),"The Polyurethanes Recycle and Recovery Council (PURRC), a unit of the Polyurethane Division of the Society of the Plastics Industry, Inc., continues to evaluate the technical and commercial viability of current and evolving technologies to recover and recycle polyurethanes. This report will update key PURRC projects targeting automotive polyurethane recovery and recycling issues. Candidate part applications will be reviewed. A project was completed in 1994 to collect post consumer seats from salvage yards and to recover the flexible foam. Process economics and seat collection viability were evaluated. Acoustical foams derived from rigid, semi-flexible and flexible foam scrap combinations are being evaluated. Flexible Slabstock foam production using up to 18% seating scrap has been demonstrated. PURRC is currently recovering polyurethane foam from instrument panels and evaluating techniques to process this scrap into acoustical padding, rebond carpet underlay and industrial structural parts. A study is underway to evaluate the most effective methods to grind flexible polyurethane scrap into powder to be used in the production of seating and headrests."
Key Considerations when Engineering a Ten Year Instrument Panel,"This paper outlines field performance shortcomings historically observed in automotive instrument panels (I/Ps) and discusses the role materials play in these deficiencies. Additionally, specific material development requirements for a ten year instrument panel are discussed. While design and the placement of adjacent vehicle components, such as windshield glass, play key roles in affecting the durability of an I/P, functional and cosmetic performance in large part depend on the materials chosen for construction. Tradeoffs in short term performance (processability during manufacture) and long term performance (field weatherability) often exist for the chemical constituents comprising instrument panel assemblies. In order to obtain an optimal combination of properties, specific performance criteria must be identified and prioritized. Well-defined test methods must be clearly documented and correlated with actual field performance in order to have a methodology to evaluate various material choices. Hopefully, this paper will serve as a framework for discussions focusing on instrument panel constructions for extended vehicle life."
Data and Methods for Estimating the Severity of Minor Impacts,"Front, rear, lateral and side-swipe collisions were staged to correlate passenger vehicle damage to motion. Data from the staged collisions are used to develop severity-prediction methods for the four collision types. Human volunteers were present in many of the vehicles tested. Their responses, and the responses of human volunteers to staged impacts in other studies, are discussed in terms of impact severity. For front and rear impacts, data are presented that correlate the post-impact condition of bumper systems to impact severity. These data build on data previously presented1,2,3. A method for computing velocity change (ΔV) for vehicle to vehicle collisions from vehicle to barrier data is presented. Data from staged low-speed lateral collisions correlate target and bullet vehicle damage to linear and angular velocity change (ΔV, Δω), impact location, pavement friction and collision force. It is shown how momentum, energy and restitution principles can be used to predict ΔV and Δω from damage. For staged side-swipe collisions, damage details are correlated to the target vehicle acceleration-time history. The vehicle motion is characterized as a vibration dose."
A Survey of Automobile Aeroacoustic Activities in Germany,"This survey reports on the salient features of the approaches being pursued in Germany by automobile manufacturers, research organizations etc. to control and inhibit the noise emission from automobiles. The results reviewed are those presented by a number of experts from industry, research organization and universities during a Symposium held in February 1994 in Germany. Topics of concern were among others: sources of noise in automobiles, noise emission measurement techniques, aeroacoustic optimisation of car body and air conditioning equipment, design of and operational experience with new aeroacoustic wind tunnels in Germany."
"Silicone Elastomer Reduces Noise, Vibration, and Squeaks in Vehicle Instrument Panels","Felt tape has traditionally been used as a cushion material between thermoplastic instrument panel (IP) components such as bezels, steering column covers, and trim to reduce noise, vibration, and squeaks that normally develop when plastic materials are adjacent to one another. However, felt tape is expensive as a raw material, and its application is labor intensive. While searching for an alternative cushion material, exploration showed that the use of a one-part, room-temperature vulcanizing (RTV) silicone elastomer offered lower raw material and labor costs versus the felt tape. The RTV silicone elastomer also did a superior job of reducing noise, vibration, and squeaks and provided improved fit for a higher level of overall quality. This paper will describe the process of evaluating the silicone elastomer as a desirable alternative and the cost comparisons of both silicone and felt tape materials. The actual process of applying the silicone elastomer as a cushioning material on the IPs of 1995 General Motors C/K light truck and sport utility vehicles will also be described. Background material on the chemistry of silicone RTVs and some of their other applications in the automotive industry will be presented as well."
Occupant Retention Glazing for Automotive Sidelites,"This paper summarizes joint efforts by Monsanto Company and Excel Industries to develop a cost effective integrated system for automotive sidelites to achieve improved occupant retention. A cost/ performance analysis of a proprietary polyurethane RIM attachment system in combination with two candidate laminate structures (Monsanto “experimental plastic”/ tempered bilaminate + annealed glass/polyvinyl butyral/ annealed glass trilaminate) was completed. While both systems yielded high energy containment capabilities, the trilaminate system was rated higher because it showed superior membrane characteristics after impact and significantly lower fabrication costs. It was determined that such a system could be implemented for an incremental cost of < $100 per vehicle."
Establishment of Countermeasures in Side Impact by Simulations,"To check sharply increasing traffic accident casualties, activities have been underway to analyze accidents and develop safety equipment Automobile makers have placed a great emphasis on improving safety in collision. In this situation, a new side impact standard was introduced in FMVSS 214 in October 1990 and will be applied to passenger cars in 1993 model year. The standard requires an additional full scale dynamic test in which an aluminum honeycomb moving deformable barrier (MDB) simulating the front end of a car is crashed at 33.5 mph into the side of a standstill car at an angle of 27 degrees. The Side impact Dummy's (SID) Thoracic Trauma index (TTI(d)), which is the average of the maximum rib acceleration and the maximum lower spine acceleration, is limited to 90 g's for a 2-door passenger car and 85 g's for a 4-door car. The dummy's pelvic maximum acceleration must remain no greater than 130 g's for both types of cars. Because most compact cars have no more than 300mm crash space between the door and the dummy, this new standard is even more stringent than the frontal impact requirements. This is especially so for a 2-door car, of which lateral rigidity is normally lower than that of a comparable 4-door car, and there have in fact been few makes which met the new standard. In order to ensure compliance with the new FMVSS 214. We have reviewed our conventional development method carefully so that necessary countermeasures for 2-door cars can be incorporated into prototypes and thus much time and money can be saved by avoiding unnecessary design reworks and retests. Previously, we used experimental methods to work out safety provisions on vehicles, but such methods could be time-consuming and expensive, and variations in test had to be always taken into account, often causing delay in engineering release for prototypes. Therefore, the method of numerical simulations was chosen to quickly perform a series of operations from factor analysis to verification of countermeasures worked out As a result goals were achieved in a relatively short time. This paper presents the method of numerical simulation."
Correction of Finite Element Model for Vibration Analysis Using the Identification System,"At the early stage of a new automobile or a new motorcycle development, it is important to grasp and improve its vibration characteristics. To satisfy this demand, finite element method has been applied to vibration analysis in recent years. However, a poor finite element model can cause not only insufficient vibration estimation but also additional development period. Conventionally, an inaccurate finite element model is corrected by trial and error technique to correspond with the experimental results. In this study, a finite element model identification system referring to experimental modal parameters has been developed. The system mainly consists of structural analysis, sensitivity analysis, numerical optimization technique, and evaluation of mode shape correlation. All these processes collectively minimize the difference of calculated and experimental natural frequencies. The system has been applied to automobile and motorcycle structures, and is confirmed to be effective in correcting a finite element model."
Challenges To Meet Heavy Duty Diesel Engine Euro II And US 1998 Emission Regulations,"The paper presents results of engine development and research activities demonstrating the potential of technology currently being developed to meet forthcoming emission regulations for heavy-duty diesel engines in Europe and USA. Development strategies demonstrated in the paper concentrate primarily on the reduction of NOx and PM exhaust emissions while maintaining engine fuel economy and durability. Furthermore, decisive aspects of engine competitiveness are considered, such as minimum necessary complexity of the technical solution in order to minimize production costs, and low engine noise characteristics."
Tools For Sound Quality Analysis In Complex Sound Fields,"As worldwide competition for agricultural and construction equipment increases, manufacturers need to distinguish their products in areas such as operator comfort and perceived quality. Advances in digital audio recording and high speed computers have presented the noise and vibration engineer with the possibility of new tools and techniques for analyzing and processing sound. This paper discusses some of the recent developments in sound quality analysis in passenger cars and how they can be applied to similar engineering problems in off-highway vehicles."
A New Test Cell Computer for Exhaust and Evaporative Emission Testing,"For the increased requirements on computer automatization and data evaluation in the field of emission testing, new programming / computer - technologies are required. To fulfill the requirements of the programmer and the user of the software, Windows NT with object oriented programming was found to provide the best possibilities to control such highly automated, complex systems. Under these directions the new Emission Test Cell Computer (short ETCC) was developed with use of the latest software and hardware technology. The Test Cell Computer provides a control system with integrated storing and paperless documentation of all relevant test data as well as protocols with all today's possibilities to create printouts. Also the managing work necessary for multiple tests running in parallel at the same time in different rooms with progress monitoring is included. The ETCC can easily be integrated into network environments and connected e.g. to existing networks. Data evaluation stations for research and development work can operate on the same network. With the integrated client/server-database, all evaluation stations have access to available data even with multiple test cell computers connected in the network. This was realized by using new technologies for the man machine interface, based on the well known Windows operating interface."
Investigation Into the Noise Associated With Air Bag Deployment: Part I - Measurement Technique and Parameter Study,"High-amplitude, short-duration noise is called impulse noise. A large body of literature on impulse noise has been developed primarily by military researchers for multiple exposures such as those caused by weapons firing. Some research into the impulse noise associated with air bag deployments was performed in the late 1960's and early 1970's to ascertain the risk of hearing loss. Several criteria for risk of noise-induced hearing loss were proposed and much was learned about the sources of the noise. Unfortunately, the instrumentation used to measure the noise in many of those studies lacked adequate low frequency response characteristics. Perhaps more importantly, results from experiments with human volunteers do not seem to agree with the proposed criteria. For this study, a new system consisting of commercially available pressure transducers and microphones was assembled and a new software package was developed. This system allows analysis of the pressure-time data using two analysis methods and criteria proposed in the early 1970's. A series of experiments using this system was run over a four year period to investigate the parameters that affect the impulse noise associated with a deploying air bag. Some observations are presented and conclusions drawn from the data."
Mathematical Simulation of Driver and Restraint Systems in Racing Saloon Car Impacts,"MADYMO 3D software was used to model a racing driver with helmet, racing harness and competition seat, and to evaluate injury parameters in a racing saloon car under European Type Approval impact conditions. Parametric changes in the safety systems were evaluated. The systems protected the driver well, although high neck torques were predicted in frontal impact. Loads on the head restraint were substantially higher than the strength required in regulations. In side impact the head passed through the open window. A window net prevented this, but the predicted loads exceeded the strength of a net tested in the laboratory."
Noise Attenuation for Polyamide Intake Manifold,"Noise Attenuation for Polyamide Intake Manifolds Since the stiffness of polyamide is lower than aluminum, special techniques have been developed to increase local and global stiffnesses of polyamide intake manifolds. The increased stiffness results in parts with noise emissions equal to or less than equivalent aluminum intake manifolds with twice the wall thickness. These special techniques enable engineers not only to attenuate noise, but to “tune” the remaining noise emissions for a desirable sound quality."
The Aero-Acoustic Wind Tunnel of Stuttgart University,"The noise emission of cruising vehicles essentially consists of tire/road noise, drivetrain noise (engine with intake and exhaust system, transmission and driving axle) and aerodynamic noise due to the flow around bodywork, chassis, wheels and cooling air flow (fan). Engines and drivetrains have become quieter due to many man-years of engineering attention and tire noise has also been reduced - at least the noise reaching the passenger compartment. Consequently, the aerodynamic noise of ground vehicles has become dominant at driving speeds above 100 kph both in interior and exterior noise. In order to determine the contribution of aerodynamic noise to the overall noise, measurements are carried out more and more in specially equipped automotive wind tunnels. Besides wind tunnels in which aeroacoustic testing was already envisaged in the specification and design phase, existing wind tunnels can be upgraded to acoustic testing by a suitable treatment of the tunnel airpath and the plenum chamber. The existing 22.45 m2 Open-Jet Automotive Wind Tunnel of Stuttgart University - Institute of Internal Combustion Engines and Automotive Engineering (IVK) - built in 1988 was converted into an aeroacoustic wind tunnel in 1993 by a novel silencing concept. In the return duct of this Göttingen-type wind-tunnel two U-bend silencers were installed upstream and downstream of the fan, using membrane absorbers as thin and smooth vertical splitters (for the low frequency range) in conjunction with profiling the turning vanes with coated porous Polyesterfoam (for the middle and high frequency range). An anechoic plenum chamber was achieved with a new type of broadband absorbers, mounted on the plenum walls and ceiling. Due to its very low self-noise level the IVK Aero-Acoustic Wind Tunnel provides a high potential for the acoustic rating of design optimizations in the development of future vehicles."
New Acoustic Feedback System,"The acoustic feedback (AFB) system is to detect the acoustic signals radiated from a loudspeaker with a microphone, and feed them back to the previous stage of the amplifier. However, there were many problems to put it into practical use. A new AFB system has been developed, where the above problems are solved by setting the microphone at the optimum position and adopting a new feedback method. This was achieved by reviewing the loudspeaker performance from a new point of view. Thus, a wide-range feedback and the improvement in the speaker response have been obtained. Also, the problems of oscillation have been solved."
A Numerical Investigation of Two-Dimensional Cavity Flow,"Results are presented for the application of an acoustic/viscous splitting technique to die computation of flowfields within two-dimensional rectangular cavities for moderate Reynolds numbers. This technique has been previously applied to cavity flows but results were studied only in die acoustic far field and limited to low Reynolds numbers. Implementation of a large eddy simulation model has allowed the Reynolds number range to be extended and direct comparison of computations with wind tunnel results for the cavity near field demonstrates that this technique, which is two-dimensional, may be used to study three-dimensional cavities, provided such cavities are fairly large in their transverse direction. In addition, the flowfield calculation is shown to be sensitive to such parameters as boundary layer thickness, filter width used in the large eddy simulation implementation, and incoming velocity profile."
Road Noise Modelling Using Statistical Energy Analysis Method,"A mathematical model was developed to evaluate design options for control of road noise transmission into the interior of a passenger car. Both air-borne and structure-borne road noise over the frequency range of 200-5000 Hz was able to be considered using the Statistical Energy Analysis (SEA) method. Acoustic and vibration measurements conducted on a laboratory rolling road were used to represent the tire noise “source” functions. The SEA model was correlated to in car sound pressure level measurements to within 2-4 db accuracy, and showed that airborne noise dominated structure-borne noise sources above 400 Hz. The effectiveness of different noise control treatments was simulated and in some cases evaluated with tests."
Acoustic Modeling and Optimization of Induction System Components,"Several aspects of the acoustic design optimization of induction systems are considered. The important role of the inlet manifold in the induction system is shown by constructing mathematical models of two levels of sophistication. A plane wave representation of the manifold is adequate when the geometry of the manifold supports only longitudinal acoustic modes. When the geometry supports transverse modes it is necessary to include the acoustic modal structure in the mathematical model comparing three mathematical models. The manifold with a conventional runner arrangement is shown to introduce harmonics of the firing frequency other than the generally assumed multiples of the number of cylinders. A manifold with runners coupled in a common plane is considered as a means of eliminating undesirable harmonics. It is shown by considering the ninth harmonic (order 4.5), that harmonics other than the integer multiples of the number of cylinders are drastically reduced in amplitude. The difficult problem of generating a good source model for the inherently nonlinear aeroacoustic source at the inlet valve is approached by the use of a simple linear model with source strength and source impedance adjusted to match with data over limited frequency ranges. The car body transfer function is shown to be an important element in the design optimization process which is based on the reduction of driver's ear noise, rather than on snorkel noise. The design process is systematized by using a SIMPLEX optimization scheme in conjunction with a plane wave modeling code. The design procedure is shown to depend heavily on access to acoustic data from a prototype vehicle. This data is required to calibrate the noise source, to establish background noise levels which limit the benefits achievable by induction system optimization, and to provide a transfer function for the car body."
Blower Motor Whining Noise - A Case Study,"Vehicle interior sound quality is regarded as a major quality attribute by automobile consumers and manufacturers. Whining noise, due to its steady state and tonal nature, is easily perceived as an annoyance to normal driving comfort. The blower motor in the climate control air-handling system can be a source of whining noise, especially when the motor is located in the passenger compartment. This paper describes a systematic case study carried out to identify the major noise generating mechanisms of a whining noise from the climate control air-handling system. The paper discusses the use of commonly available tools and techniques to resolve typical automotive NVH concerns resulting in improved sound quality. Particular measurement and analysis techniques presented include sound field mapping using acoustic intensity, resonance identification using transfer functions, three-axis spectrum analysis, and some physical modifications to the source and propagation paths. A variety of objective noise and vibration data is presented and explained. The investigation concludes the source of the whining noise as a type of brush noise. The path is identified as structureborne noise transmitted from the brush-commutator interface, through the motor support structure, to the blower assembly casing, where it is radiated from various positions as airborne noise. The recommended solution is to mount the motor so that it is vibration isolated. Data measured on an iso-mount design is presented to confirm this solution."
Analytical and Empirical Evaluation of the Impact of Solar Control Glazing on the Thermal Environment in Vans,"Spectrally selective glazings that reduce the amount of solar energy entering a vehicle have been developed by PPG to enhance overall passenger comfort and help automotive designers and engineers manage the thermal environment in vehicles. That environment is being affected by such factors as the use of larger glass surfaces, smaller engines, fuel economy goals and refrigerant issues. To quantify the effects of a variety of solar control glazings on passenger comfort and thermal environments, PPG has conducted in-vehicle tests in Arizona evaluating the following glazing systems: the SUNGATE® Automotive windshield, which uses a transparent infrared-reflective coating; SOLARGREEN® Glass, a special composition that reduces infrared energy transmittance, and GL-20™ Glass, a deep-tint privacy glass. The evaluations included measurements of passenger compartment air temperatures, material temperatures, air flow, heat flux through non-glass surfaces, passenger comfort and air conditioner performance. Test results show that these glazing systems are effective in reducing maximum temperatures in parked vehicles, improve cooldown performance following static exposure and reduce compressor work loads. This all leads to improved passenger comfort, improved fuel economy and less damage to interior materials. While desert testing will continue to play a role in assessing in-vehicle performance of glazing systems, there is a need to provide such information in real time as auto manufacturers continue to reduce their development cycle. To that end, a predictive analytical model has been developed. The foundation for that approach is a thermal simulation code that has been modified to allow changes in orientation and the capability to use short time step boundary conditions. Initial efforts in this project, both analytically and empirically, have been focused on simulation of the minivan vehicles. The dynamic nature of both the simulation and the empirical drive test required observation of additional temperature, flow and heat flux sensors throughout the vehicle. Comparisons of the simulation models to empirical results confirm that the analytical approach captures the measured performance of new glazing products in vehicles."
Acoustics and Microgravity Flight,"The effects of acoustic levels in manned space vehicles was not thoroughly appreciated until the STS 40 mission, Spacelab Life Sciences 1 (June, 1991). Previous to that mission, waivers were submitted and equipment operated without overwhelming effect on ongoing flight activities. The factors of multiple pieces of noise producing equipment operating simultaneously, operating in the vicinity of crew sleep stations, and operating for this long of a mission (10 days) became relevant in crew tolerance, fatigue, communication, and permanent shifts in hearing thresholds. Because this was a life sciences mission, accurate instrument measurements were obtained of acoustic levels in the middeck, flight deck and spacelab during flight and physiological measurements were obtained from the crew members during all phases of the mission. Due to the STS 40 results, a Spacelab/Payloads Acoustics Working Group (SPAWG) was formed post flight to address acceptable acoustic limits. The charter of this group was to: Identify and assess orbiter, spacelab, subsystems, and experiment hardware with the objective of reducing the overall acoustic levels on the Middeck and within the Spacelab module to acceptable flight levels. Members of the group represented NASA headquarters, field centers, and payload developers. This paper will briefly address the acoustic impact on crew persons during STS 40, the recommendations of the SPAWG, and current means of addressing acoustic issues within life sciences hardware flown on microgravity missions."
Customer Based Holometric Analysis,"This paper describes a test-based process used to identify structural characteristics of a vehicle windshield wiper system that contribute to customer impression of the sound. The method of paired comparisons determined which wiper system sounds customers preferred. Annoyance ratings of sound components then identified contributors to customer preference. Wiper motor noise was identified as the major annoyance factor affecting system sound quality. This information guided a study of the structures responsible for radiated motor noise. Laser based test methods were used to interrogate the structures clearly identifying transmission paths into the surrounding structure. Paths were then modified reducing structure-borne motor sound as measured with acoustic retests. Thus, a logical technique for hardware testing and modification guided by customer perceptions is presented allowing efforts to be focussed on the most critical aspects of vehicle sound quality."
Objective Analyses of Binaural Recordings,"Aurally-adequate sound measurement technology makes use of both present psychoacoustic knowledge, e.g. loudness, roughness, fluctuation, sharpness and so forth, and Artificial Head measurement technology with transmission characteristics comparable to human hearing. By taking into account psychoacoustic evaluation parameters very often good results for judging sound events with regard to sound quality, as compared to subjective impressions, can be achieved. If a sound situation is relatively complex, i.e. if it consists of various single sound sources at different spatial positions, significant level and phase differences between the left and right ear occur which - in comparison with a monaural evaluation - can yield different results. Such effects have been observed for some time already. Speech intelligibility in a noisy environment, e.g., depends on the positions of the sound sources. Furthermore, investigations into noise in workplaces showed that binaural recordings as compared to monaural recordings caused significantly different physiological reactions of the test subjects. Moreover, it became evident that noise annoyance of single sound sources in a complex mixture of sounds does not only depend on absolute parameters such as A-weighted SPL, loudness etc., but also on their localization. In the interior of a car, for instance, the individual engine orders can produce significant amplitude and phase differences between the left and the right ear, due to wave and multipath propagation, influencing the subjective evaluation. There are no objective measurement procedures available at present. In the last decades a lot of scientific basic research was done on binaural signal processing. Due to the complexity of signal processing in human hearing there have been no complete models yet which simulate binaural signal processing in a simple way and thus constitute a basis for the objective determination of sizes, derived from a binaural measurement to describe subjectively perceived sound quality. Therefore, investigations aiming at the selection of certain signal components from a complex mixture of sounds were carried out, based on additional information such as directional sound incidence of the sound sources under test or engine r.p.m. for selecting individual engine orders. On the basis of known models to predict speech intelligibility in a noisy environment, binaural models for the objective determination of sound quality, based on these simple application examples and Artificial Head recordings, were developed."
Engine Noise Reduction Using Narrowband Feedback Control,"A narrowband feedback control is developed to cancel periodic noise. The method consists of digital bandpass filters centered at a reference frequency and its harmonics. Each of these bandpass filters is then followed by a finite impulse response (FIR) filter which changes the phase of the control signal to achieve the 180° phase shift in the open loop system. A gain is applied to the control signal to adjust the overall noise reduction, considering reasonable stability margins in the system. In a set of experiments the proposed technique was compared with the filtered-x adaptive feedforward control method. The periodic noise, introduced by a noise speaker, inside a reverberant box was controlled (reduced) using both techniques. With the gain properly adjusted, the amount of noise reduction at the microphone was slightly less than that achieved by the filtered-x adaptive control, but the stability characteristics of the feedback control system was considerably better. The feedback system was able to maintain a gain margin of about 6 dB's and a phase margin of 45° over the entire frequency range of interest while the feedforward controlled system became unstable at a few frequencies even with very slow adaptation rates. The proposed feedback technique was also used to attenuate the interior noise, due to the firing of the engine, in an automobile. The reduction of up to 8 dB's in sound pressure level at the driver's head was achieved."
Application of Noise Control and Heat Insulation Materials and Devices in the Automotive Industry,"Automotive noise control involves many aspects of the total vehicle design - the powertrain, body structure, chassis and so forth. Noise control materials in conjunction with intelligent vehicle design can help produce a pleasant, desirable vehicle. Understanding the basic functions and uses of noise control materials is one of the objectives of this paper. In some situation, thermal insulation materials are combined with or used in conjunction with noise control materials, and an understanding of the thermal properties of materials can be useful. Vibration isolators are important devices in controlling the transfer of sound and vibration energy and these are discussed."
Investigation of Different Techniques for Quantifying Automotive Panel Noise Radiation,"In the process of determining optimal treatment locations and compositions for automotive noise control parts, it is necessary to know both low frequency and high frequency sound contributions of automotive interior sheet metal panels. Several techniques of experimentally assessing individual panel contributions to coherent, low frequency noise as well as incoherent, high frequency noise are investigated. These include use of a sound intensity probe, a pressure gradient microphone and an accelerometer for measurement of panel vibrations. Acoustical insulation of all interior surfaces except a particular surface of interest (the “windowing” method) and boundary element modeling (for exclusively low frequency characterization) are also investigated. While no one technique is ideally suited to determining contributions in the entire audible frequency range, the boundary element method was found to be particularly useful for coherent source characterization, while the more traditional “windowing” method is well-suited to incoherent source characterization."
Sound Quality Assessment of Powered Seat Adjusters,With the extensive improvements achieved in vehicle driveline and road noise quality manufacturers are turning their attention to component and ancillary noise sources and expecting their suppliers to include sound quality in the assessment of their designs. This paper describes an investigative project into the principal components contributing to the perceived sound quality of powered seat adjusters in passenger vehicles and the statistical methods of analyzing jury preference data.
The Ford Motor Company Advanced Engineering Center,"The Ford Motor Company Advanced Engineering Center contains 100,000 square feet of sound and vibration laboratories, induding full vehicle chassis dynamometers, powertrain dynamometers, and sound quality evaluation chambers. The facility houses the first U.S. All-Wheel-Drive NVH Chassis Dynamometer (4 independent motor drive), the first U.S. All-Wheel-Drive NVH Powertrain Dynamometer (4 independent motor drive) and other unique elements, such as innovative wedge construction for the acoustic chambers."
The Chrysler 3/8-Scale Pilot Wind Tunnel,"The Chrysler 3/8-scale model automotive wind tunnel is a pilot facility for a planned full-size tunnel of the same design. The 3/8-scale tunnel, which has a complete compliment of instrumentation including a pressure system and high-precision balance, will also be used for 3/8 model aerodynamic development testing of vehicles after piloting is complete. The tunnel is convertible from a slotted-wall test section to a semi-open jet test section. Commissioning, calibration, and piloting results show the performance of some features being piloted including slotted-wall effectiveness, open jet collector performance, and tunnel background noise levels. Calibration results include static and dynamic pressure distributions."
On the Induced Noise of Test Sections in Different Wind Tunnels and in the Cabin of a Passenger Car,An acoustic comparison test of eleven European and two American full-scale automotive wind tunnels was carried out with a passenger car. The scope of investigation comprised in-flow and out-of-flow background noise measurements of the empty test sections as well as interior noise measurements inside the passenger compartment of a standard type Volkswagen Passat Variant CL. For this purpose seven different vehicle configurations were investigated in the various wind tunnels. The aim of this experimental investigation was to establish physical criteria in order to carry out a suitable acoustic comparison between wind tunnels with different types of test sections and to establish upper limits of wind tunnel background noise levels where acoustic measurements inside a passenger compartment are questionable.
Measurement and Analysis of Gaseous Exhaust Emissions from Recreational and Small Commercial Marine Craft,"In general, propulsion systems used in recreational and small commercial marine craft exhibit some unique design and installation characteristics, which demand special attention from the standpoint of emissions measurement and data interpretation. For example, the exhaust system is often a compact folded design which terminates partially or completely underwater. Also, water is normally present throughout much of the exhaust ducting in order to provide cooling, noise reduction, and tailored exhaust tuning characteristics. Marine industry efforts have led to the development of a measurement standard (ICOMIA 34-88) which is being used to evaluate marine propulsion systems in anticipation of future exhaust emission regulations. This paper discusses the rationale used to develop the measurement and data analysis procedures, and presents the complete ICOMIA standard as an appendix."
Standardization of a Test Track Surface for Use During Vehicle Noise Testing,"A group within the International Organization for Standardization has worked out a standard for a road surface intended to be used during vehicle noise measurements according to the ISO 362 and 7188 procedures. The surface should be equally suited for use in similar measuring procedures where full-throttle operation of vehicles is needed and where the influence of the surface on noise emission and propagation must be kept at a minimum. Several test tracks have been laid according to the proposed specifications. A Round Robin Test has been conducted in which five cars and one truck were run on a number of test tracks in Europe and Japan. The results show that the surface meets the basic requirements of giving low tire/road noise while still having negligible sound absorption characteristics. Also, the site-to-site variability is low. In this paper, the convener of the working group presents the work and a preliminary proposal. The final proposal is scheduled to be presented in the summer of 1991."
Active Control of Simulated Road Noise,"Active noise control is a potential method for controlling troublesome low frequency road noise in the passenger cabin of automobiles. In this investigation, the control of simulated road noise in a four door automobile is studied. Active control of road noise requires that the inputs to the controller sense a significant part of the energy causing the noise. Only the coherent energy between the input sensors and the performance microphone is controllable. An investigation is conducted of the control achievable using accelerometers mounted at various positions near the rear wheel of the vehicle as inputs to the controller. The best input sensor location was used with a commercial active noise controller to reduce simulated road noise near the driver's head location. The measured reduction is compared with the results predicted using the coherence. Additional controller simulations were developed to predict and better understand the performance of various controller types in this automobile."
Acoustic Analysis of Truck Cab,"This paper presents the results of acoustic analyses of light duty truck cabs by actual vehicle testing and by numerical analysis utilizing the boundary element method (BEM). In the resonance mode analysis using BEM, by taking into account the vibration characteristics of cab panels, the presence of the modes other than the purely acoustic cavity resonance modes were confirmed. The contribution of the panel vibrations to booming noise that occurs in actual light duty trucks was analyzed. BEM analysis showed that some of the panel vibration had a negative contribution to booming noise. In other words, decreasing vibration in such a section was shown to increase sound pressure. The results of the BEM analysis match well with actual test results. It has thus been demonstrated that BEM is an effective method for analyzing truck interior noise reduction."
Integrated Flight-Propulsion Control Concepts for Supersonic Transport Airplanes,"Integration of propulsion and flight-control systems will provide significant performance improvements for supersonic transport airplanes. Increased engine thrust and reduced fuel consumption can be obtained by controlling engine stall margin as a function of flight and engine operating conditions. Improved inlet pressure recovery and decreased inlet drag can result from inlet control system integration. Using propulsion system forces and moments to augment the flight-control system and airplane stability can reduce the flight-control surface and tail size, weight, and drag. Special control modes may also be desirable for minimizing community noise and for emergency procedures. The overall impact of integrated controls on the takeoff gross weight for a generic high speed civil transport is presented."
Development and Application of Simulation for Low-Frequency Boom Noise and Ride Comfort,"This paper investigates a new approach to the quantification technique for road induced vehicle interior noise and vibration within the frequency range up to 40 Hz. By employing the least squares method, both vertical and fore-aft load to each wheel were quantified using transfer function and actual vibration response of the vehicle driven on a road. The coupled structural-acoustic vehicle model using the finite element method, which is also detailed in this paper, is combined with the quantified input load to simulate road induced interior noise and vibration response. Experimental verification, which indicates reasonable accuracy of the simulation, and an application for the prototype development are also presented."
Development of Composite Materials Applications to Production Nacelle Component Structures,"The main engineering problems requiring solution in a development programme aimed at the application of composite materials to selected nacelle components are reviewed. The components chosen were characterised by important special features including acoustic performance, fireproof capability and resistance to fan-blade off effects. The subsequent application of the developed technology to meet production nacelle requirements and Airworthiness compliance needs is discussed."
Corrosion Protection of Galvanized Steel Sheet-Corrosion Investigation of Field Vehicle,"Three doors from three field vehicles made with one-side galvanized steel on the inside of the outer panels were investigated for perforation corrosion using microscopic and analytical methods after 8 or 10 years' field exposure in the snow-belt areas of North America. Perforation of these doors occurred within the lapped part of the door hems. Outer panel perforation began at the zinc layer on the inside surface of the outer panel at the lapped part and/or at the “bent part” of the outer panel of the door hems. Details of the micro corrosion behavior for the inside surface of the outer panel were made clear using EPMA analyses. The corrosion products on the inside surface of the outer panel were identified with X-ray diffraction. Initially, zinc corrosion begins at the zinc coating layer of the upper side at the wax-free zone of the lapped part. Eventually zinc corrosion occurred beneath the wax layer as “Under-film corrosion”, proceeding gradually from the bottom to the top of the lapped part. The zinc is transformed into ZnO from the protective ZnCl2·4Zn(OH)2 initial product. Eventually, the steel substrate corrodes after the zinc coating loses its sacrificial corrosion protection. The steel is transformed into Fe3O4 and α, γ-FeOOH. It was found that this corrosion behavior was a common phenomena for the observed door hems."
Rollover Crash and Laboratory Tests of Ejection Reduction By Glass-Plastic Side Windows and Windshields,"About one fourth of the occupant deaths in passenger cars in the United States involve either complete or partial ejection. Approximately one half of these ejections are through glazing areas. This paper presents research results which demonstrate the potential of glass-plastic glazing to significantly reduce ejections through motor vehicle windows. Four passenger car and four light truck and van rollover experimental crashes were conducted. All the vehicles had glass-plastic front side window glazing. One of these included the improved glazing with a movable encapsulated “offset T-edge” design. Two in addition had glass-plastic windshields. Even with glass breakage and window frame distortion, the glass-plastic glazings maintained their “safety net” ejection reduction function. Laboratory dummy drop and sled tests of the movable glass-plastic glazing side windows are reported. Component tests are discussed which use 10 pound and 40 pound, eight inch diameter, chamois - covered spheres as test devices to evaluate the characteristics of the improved glazing relative to the Head Injury Criterion, laceration, and ejection reduction. Research remains to be carried out to assure sufficient deformation of the safety net glazing system to provide acceptable neck loads under severe glazing contact conditions."
Carbon Epoxy Perforated Skin for Nacelle Acoustic Treatment,"The acoustic treatment requirement for jet engine nacelle inner flowpath leads to using perforated skin. Formerly in light alloy these skins are now composite and new techniques have been developped to achieve the perforation. After reviewing different possible techniques (mandrel tool, abrasion, stamping, mechanical drilling,…) one process is chosen and described in terms of skin mechanical properties, cost, and production facilities."
Parameter Identification for Noise Prediction in Car Structures,"The investigation of the static behaviour of structures, especially car bodies, by analytical methods is a very important and widely used tool in the automotive industry. It is much more difficult to predict noise phenomena. The key point is that many physical quantities determine the sound in the car (1)*. The relevant physical effects must be identified in order to get a reliable mathematical model. The paper describes how this can be done by a combination of experimental and analytical works. The frequency range of interest is up to 200 Hz"
Using Fiber Optics and Laser Fluorescence for Measuring Thin Oil Films with Application to Engines,"A new method has been developed for measuring the oil films on cylinder walls in engines that offers benefits in improved understanding of oil transport and consumption. The unique aspect of this work is that fiber optics and laser induced fluorescence are combined to measure the oil film thickness. As a result the system is much less intrusive than previous methods using windows to observe the fluorescence. Static tests were used to demonstrate the characteristics of the technique. Dynamic tests, performed on a Cameron Plint wear tester, showed the capability of the system to measure thin films under dynamic conditions and at high loads and temperatures. Finally, the system was installed in a diesel engine and used to measure oil film thicknesses under fired conditions."
Side Impact Crashworthiness Design: Evaluation of Padding Characteristics Through Mathematical Simulations,"The National Highway Traffic Safety Administration (NHTSA) has developed a lumped mass computer model which simulates the interaction of a struck car door and an adjacent two dimensional seated dummy in side impacts. This model was used to investigate the effect of various vehicle design parameters on occupant responses and to define various methods to improve vehicle safety performance. This paper discusses the effectiveness of door padding and side structural stiffness to minimize potential for occupant thoracic injuries in 90° side impacts. Occupant response data were obtained with the aid of the computer model for a Moving Deformable Barrier striking a car at lateral velocities of 25, 30 and 35 mph. To determine the optimal padding and structure needed to minimize potential occupant injury, the Thoracic Trauma Index (TTI) was mapped in terms of different levels of struck car side stiffness and padding characteristics."
About the Threshold for Fatal or Potentially Fatal Injuries in Car-to-Car Side Collisions - A Comparison Between Real Accidents and PMHS-Tests,"This analysis is part of a retrospective real accident study of 670 occupants in 428 cars. In most cases the real accidents were reconstructed from police reports by means of photographs, accident drawings and descriptions of the damaged cars. In fatal crashes the cars, and in most cases the sites of the accidents were examined. Among 272 occupants involved in car side collisions, we found 41 belt protected near side front passengers, whose cars were impacted by another car with main impact points at the front passengers' doors and B-pillars. The analysis of the correlation between technical parameters of the real accidents and injuries of the passengers showed a high significant discrimination between MAIS and some regional AIS 0-3 on one hand, and MAIS and some regional AIS 4-6 on the other hand already for each of the technical variables EES, delta v and maximum deformation. The comparison between these 41 real accident cases and 57 PMHS (postmortem human subjects) tests (15)* proved a significant difference between the thresholds for fatal injuries in respect to maximum deformation. The mean values of maximum deformation for fatal injuries in the real accidents were significantly higher than in the PMHS-tests. The possible causes of the differences are discussed."
Cold Start Improvements With a Heat Store,"The Heat Battery, a latent heat store, accumulates waste heat of the engine and preserves it by efficient heat insulation. On the next cold start, after a day or a weekend, the heat is released with an initial power of 50 to 100 kW. This energizes the vehicle heating system within seconds, allowing for hot air to flow instantly to the cabin and to the windshield. The passenger comfort is immediately felt, and the windshield can be defrosted or demisted without manual help. Due to the high heating power the engine will warm up within 30 seconds so that the tailpipe emissions of carbon monoxide are reduced up to 50% and unburnt hydrocarbons up to 30% in the first bag of the CVS-Test."
Overview of a Study on Direction-of-Motion Stereotype Strengths for Automobile Controls,"Virginia Polytechnic Institute and State University recently conducted an SAE sponsored research study investigating directional stereotypes of six types of automobile controls: power mirrors, power windows, manual windows, stalks, generic controls, and power door locks. The objective was to determine stereotype strength and the reasons for the strengths. Two hundred subjects participated in this study. This paper provides an overview of the results of the study and recommendations made therefrom."
A Plan to Prevent ESD Damage on Electronic Components at an Auto Radio Process Assembly,"Everybody has already had the ungrateful experience of walking on a carpet tile and receiving an electric shock just by touching a door knob. What many people don't know is that, simply the fact of walking a few meters over the carpet can generate some kilovolts of electrical charge and cause a damage of some thousand dollars on electronic devices such as computers, radios, electronic controls, etc, due to the fact that they have components sensitive to a few hundred volts or less. The most common way of generating Electrical Static Charge is frictioning two different materials against each other. Electrons are transfered from one surface to the other making one more positive then the other this imbalance can easily reach the order of some hundred volts. Today, the automotive industry uses a large quantity of a wide range of electronic components in its products (cars, trucks, etc.) not only for entertainment, but also on the drive control area, (engine, powertrain control etc.). Where no failure can be admitted because driveability and safety can not be jeopardized. So, it is very easy to undestand why an Electronic Assembly Plant that uses millions of sensitive devices every year needs a well defined plan to prevent the effects of Electrostatic Discharge."
Use of One ST9 Timer for Handling a J1850 50 Kbit/Sec. Implementation,"This paper describes a mixed hardware and software implementation for the SAE-J1850 protocol (1). This implementation is general and can be adapted to most J1850 based systems. Each node is entirely managed by one ST9 microprocessor. That means that the same micro controls the application and the bus. To interface with the bus the micro uses one ST9 16-bit timer and two register banks. As a result this system can be implemented using any ST9 microprocessor. Only a simple external circuitry is needed to drive and buffer the bus, as well as filtering the incoming signals. Bit decoding, CRC check/generation and consistency checks are done internally to the micro, thanks to the sophisticated hardware of the standard ST9 16-bit timer. The data link, network, transport, session and presentation layers are implemented by software. Therefore this implementation is perfectly suited for nodes with application layers of medium complexity, such as doors, lights, speed control, A/C control, instrumentation, distributed audio modules, etc."
Temperature Measurements During Flash Welding Thin-Walled Door-Frame Components,"This study was conducted to examine the effect of flashing conditions on the resulting temperature profile during flash welding automobile door frames. Previous work on temperature profiles of flash welds has shown that at some point in the welding cycle a steady state temperature is reached, minimizing the need for further flashing. The indication of such a minimum flashing time allows flashing conditions for any application to be optimized. Unfortunately, previous work has been limited to rather heavy section materials, and the results could not be directly applied to the flash welding thin sections typical for door frames. This program was a preliminary study to examine the effects of initial flashing velocity and flashing acceleration on the resulting temperature profiles in U-shaped channel sections. Work was done on a cam driven flash welding machine supplied. Flashing conditions were varied by using cams with different profiles. The first cam was a linear cam typical of that used for production of this part. In addition, three new cams were prepared. These included a cam with a linear flashing profile using twice the initial flashing velocity of the production cam, and two cams with parabolic flashing profiles. Both parabolic cams profiles used half the initial flashing velocity of the original cam. All cams used roughly the same flashing time, resulting in different degrees of burn-off. Temperature measurements were made by locating thermocouples at increasing distances from the original interface. During welding, temperature was recorded from these thermocouples as temperature versus time data. For each set of flashing conditions, separate experiments were run to characterize temperature profiles on the three sides of the channel section. Resulting temperature versus time data was then transformed to temperature versus distance from the flashing interface data. This data was curve fit to an exponential expression, and the results of that curve fit used to calculate effective forge depth of the workpiece. The results of this program show that the parabolic cams reach steady state temperature faster than the linear cam, and are consistent with the published literature on heavier section flash welding. However, it was also noted that excessive flashing velocities (as a result of either a high initial flashing velocity or too high a flashing acceleration) tended to overheat the part. Higher flashing velocities result increase the rate of heat generation during flash welding. It is believed that the relatively long stick-out lengths used in this application, and the relatively poor conductivity of the dies prevented heat from being extracted at a sufficient rate to maintain a stable temperature profile. Apparently, heat generation needs to be balanced between that necessary to achieve stable temperature conditions in a reasonable time, while not overheating the workpiece."
Advances in Thermoset Injection Molding,"Injection molding of thermosetting materials such as low profile SMC/BMC composites found increasing application in the transportation industry in the eighties. Such automotive parts as front end panels and rear/hatchback doors have grown in usage. The rear doors have reached exceptional production levels of 2500/day in a single plant. The injection process offers the advantages of greater automation for the mass production of body panel parts compared to compression molding. However, the injection molding of fiber reinforced low profile composites suffers from a severe reduction in physical properties. This is particularly true for impact strength which can be one-third that of similar compression molding materials. A primary reason for this is due to the degradation of the reinforcement during the processing/molding. Efforts at increasing the physical properties through processing changes have many times caused problems with the surface smoothness of the moldings. Should major improvements in impact strength be coupled with excellent surface appearance the injection process could be applicable to automotive hoods, doors, deck lids, etc. The resultant application of automation could provide a more favorable cost structure for these composites versus metal even at high volumes of production. This paper reports on a concerted study of this problem involving examination of the organic matrix system, shrinkage control materials, interfacial agents, glass sizing changes, chemical thickening and various processing parameters and injection molding machines. This work has resulted in truly super Class A surface molding at impact strengths 80% above those of the best standard injection materials. Progress of this nature signals the beginning of a new day in low profile thermoset injection molding."
Gas Injection Molding of Thermoplastic Composite Window Guidance Channel,"Gas injection molding of reinforced engineering plastics for structural applications is a very innovative approach, but is still in an infancy stage. The requirements for window guidance channel are: dimensional stability, high strength to weight ratio, no warpage and low wear. The composite materials with hollow tubular structure can only meet these requirements based on FEA analysis. We evaluated 30% glass filled polyester (short and long glass fibers). The part and tool designs are the key parameters for successful results which are discussed. Information on current gas injection molding technologies is discussed. The new software ‘C-Gas flow analysis’ was used to optimize gate design and process parameters. The design of experiments based on Taguchi method was used. Both available technologies, i.e., gas through nozzle and gas through runner or cavity were tested. The cross section analysis was done using CAT Scan. This is the first structural application of gas injection technology which is fully tested and approved according to GM specifications. We received Society of Plastic Industries (SPI) ‘Award of Excellence’ for design and application development in February 1990."
Aerodynamic Noise of Ground Vehicles,"As engine, tire, and other automobile noise is reduced and as driving speeds increase, aerodynamic noise sources on ground vehicles are becoming relatively more important. They often dominate at cruise speeds of 65 mph. Aspiration and leak noise are strong sources but generally can be controlled by known methods. Turbulent pressure fluctuations due to separated and vortical flows are also strong sources. Much interior noise is caused by transmission of these external pressure fluctuations through windows and other surfaces. The paper presents the variety of aeroacoustic sources on automobiles and reviews the state of experimental data, of analysis methods, and noise reduction principles. A new correlation method for predicting external fluctuating pressures in separated regions is presented."
Climate Measurements for Glass with Different Energy Properties,"Recent developments in glass treatment techniques have made it possible to improve vehicle compartment climate considerably. At the same time, it has become obvious that traditional temperature measurements do not cover the total need for describing climate properties. This is due to the fact that human heat balance, which is the fundamental process behind feeling cold or hot, is a function not only of temperature but also of draft and radiation. Coating glass is one means of preventing solar radiation from coming into the compartment. In doing so, the solar heat load through the glazing can be reduced by some 50 %. This, of course, gives a lower compartment temperature in parking conditions and also a faster cool-down in hot climate. It has two major secondary impacts on the human being: At a given air flow through the compartment, the necessary inlet temperature is increased, thereby causing less draft. Direct radiation on body surfaces is also reduced. The total evaluation of glass with reflecting or absorbing properties must therefore include measurements with instruments like the Bruel & Kjaer comfort meter or the Voltman system as presented in SAE reports nos. 850042 and 890049. The latter system, which gives a total picture of heat load on different body parts in a given situation, is of course the most sophisticated method for this part of the evaluation. In this paper, some suggestions are given for testing routines. They include: parking heat-up and idling cool-down tests. Voltman on-road testing and simulated on-road testing outdoors."
Development of a Test Procedure for Quantifying Performance Benefits of Solar Control Glazings on Occupant Comfort,"The evaluation of the performance benefits of solar load reducing glazings using production vehicles is key to the establishment of the product cost/benefit ratio. Climatic windtunnels normally used to evaluate heat gain and vehicle cooldown can not provide true solar simulation. Comparative testing using a test car and a control vehicle must therefore be conducted outside in uncontrollable ambient conditions. The subject paper deals with the development of a testing methodology capable of quantifying thermal performance differences, as low as 5%, resulting from component differences, including glazings. The procedure described includes the use of B & K Thermal Comfort Meters to standardize the refrigeration system performance and to evaluate the rate of vehicle interior cooldown. Data taken during summer test programs in the Southwest for evaluation of heat absorbing glazings will be reviewed. Data to be presented include interior air and surface temperatures during soak testing and cooldown comparisons under city drive conditions. The general relationship of comfort meter data to driver comfort index will also be discussed."
Solar Control Glass with Neutral Color for Automobiles,"This paper describes monolithic solar control glass with high durability and neutral color (colorless reflection) for automotive windows. Layer systems of the solar control coating are composed of double layers (oxide/nitride/glass) and triple layers (oxide/nitride/oxide/glass), where a titanium nitride film is chosen for solar energy reduction and a novel zirconium based oxide film with a low refractive index is used as a protective layer together with reducing optical interference color. The nitride film and the oxide film are prepared by reactive dc magnetron sputtering from a titanium target and an alloy target without intentional substrate heating, respectively. Durability of the double layer coating is investigated against abrasion, chemicals and weathering. When the coating is applied to all windows of a passenger car, the reduction of a solar heat load is evaluated through an air-conditioner at simulated car speed under simulated solar radiation."
Non-Destructive Replication Technique for the Examination of Phosphate Crystal Morphology on Vehicle Assembly Lines,"Destructive or indirect methods have been available for evaluating phosphate crystal morphology on car bodies pretreated on a vehicle production line. Either the panel in question is removed, thereby destroying the car, or flat panels are hung in the window openings with the assumption that the same morphology exists over similar substrate surfaces on the stamped autobody. The replication technique described in this report has proven to be a viable option for examining the phosphate crystal morphologies present on various automobile substrates. The details of this replication technique along with crystal morphologies associated with different substrates and degrees of forming are included in this report."
Air Conditioning Electric Vehicles with an Electronically Driven Variable Speed Scroll Type Compressor,"A realistic air conditioning system for electric vehicles, (EV), which minimizes the sacrifice of drive range is proposed in this paper. A variable speed semi-hermetic scroll compressor and an automatic louver outlet air temperature control method for a small delivery van are used to attain suitable cooling performance and interior temperature controllability with acceptable noise characteristics. This air conditioning system, (A/C), offers a pre-cooling feature simply by tapping power from commercial electricity outlets before departing for service. The effect of a practical heat influx reduction applied to the vehicle, and of condenser improvement, is evaluated in terms of the electric power consumption and the actual sacrifice of the vehicle's drive range."
On-Line Paintable Polypropylene Compounds for Automobile Body Panels,"The use of plastics to make the bumpers, doors, fenders and other exterior body panels has increased greatly in recent years. Efforts have been made to achieve on-line paintability so that plastic and steel body parts can be painted at the same time. This has already been accomplished for polyamides and certain polymer alloys such as polyphenylene ether/polyamide. In the field of general-purpose plastics such as polypropylene, recent advances in composite material technology have made it possible to develop general-purpose plastics that display properties comparable to those of engineering plastics. We have succeded in developing new polypropylene compounds which combine excellent thermal properties, high impact strength, and low coefficient of linear expansion. In addition, they can be painted on-line in lamp finisher and front bumper applications."
Development of Rubber Contacts Used for Power Window Switches,"We have developed a power window switch unit for use in multiplex wiring systems for automobile doors. As the systems are multiplexed, signal switches mounted on PC boards prove to be more advantageous than conventional switches having a metal spring and metal contact. We chose to use a rubber contact in one of the signal switches, and combined a good operational feeling into the rubber contact, thereby succeeding in designing a switch structure that requires less parts. We expressed the operational feeling of the switch by four values, and designed the switch with the help of CAE to meet each of the values. We could therefore develop a rubber contact with an operational feeling as high as we had aimed without the need to make any prototypes."
On Determining the Relationship Between Vehicle Value and Interior Noise,"A PC based survey tool has been used to measure the value of a luxury vehicle as a function of its interior noise level at 70 mph. Two straight lines were required to fit the change in value (measured in dollars) with noise level depending upon whether noise was greater or less than a baseline level of 66 dB(A). The slopes of the lines differed by a factor of two with the value loss curve asociated with a noise increase from the baseline level being the steeper of the two. A difference in the value relationships between gains and losses in this manner is expected from prospect theory. When the noise level in dB(A) was adjusted to represent a sones-like scale using a conversion based upon a broadband noise spectrum, the measurements followed a single straight line reinforcing the view that the sones scale is more nearly a “pure” psychometric scale than dB(A). The results also suggest that, when persons are asked for their willingness to pay, their response threshold for losses is much more sensitive than their threshold for gains. The findings are discussed in terms of their implications on designing automobiles for competitive markets."
Safety Testing and Evaluation of Polycarbonate Vehicle Glazing Using Full Scale Crash Testing Procedures,"This paper presents the results of a comprehensive research program addressing the safety issues pertaining to using Polycarbonate glazing for non-windshield vehicle glazing. A series of crash test procedures were used to evaluate the Polycarbonate glazing alternative. The test procedures utilized included High Speed Lateral Impact (HSLI), Narrow Object Intrusion or Pole Impact, Dynamic Rollover, and Inverted Vehicle Drop tests. It should be noted that component-level dynamic impact testing of a variety of Polycarbonate designs was previously conducted as part of this ongoing research program [1]. This testing included 40 lb guided headform and Free Motion Headform (FMH) testing. In regard to vehicle glazing, there are a number of important occupant safety issues. These include occupant containment, injury due to occupant impact with glazing, and laceration. Throughout the project, emphasis was placed on the careful monitoring of the test results with regard to these three issues. The intent of this study was not to specifically highlight the safety benefits of Polycarbonate glazing, but more to fully investigate the Polycarbonate glazing alternatives to determine whether there are increased safety risks accompanying a switch to this type of glazing. The vehicles that were used for this project are quite popular to the North American market. These vehicles included a 1997 Ford Taurus, a 1997 Chevrolet Cavalier, and a 1997 Dodge Grand Caravan. For each Polycarbonate test, the vehicle's non-windshield Tempered Glass glazing was replaced with 4 mm Polycarbonate glazing. The Polycarbonate glazing was bonded into the vehicle using an automotive adhesive common to the industry. Although this approach is not feasible for moveable window applications, one of the reasons it was chosen was to produce the highest possible loads on the Polycarbonate window. Throughout this study, it became increasingly clear that there are many safety issues to consider with both Polycarbonate and Tempered Glass. From an injury standpoint, the three most common areas associated with glazing are laceration potential, impact injuries, and ejection. This project focused on these three areas. For the most part, the evaluation of the glazing performance with respect to these areas is direct and the techniques used for assessing these injuries is accepted by the safety industry. The difficulties arise when considering the relationship between impact injury and ejection. When considering overall safety, if there is glazing breakage, then there is higher potential for occupant ejection. Conversely, if there is not glazing breakage, then the potential for occupant ejection is eliminated (at least through the glazing), yet the injury potential due to glazing impact is increases. The issue arises as to how the injury due to the glazing impact compares to the injury potential when there is a partial or full ejection. Whenever there is an ejection of any kind, the range of objects that an occupant can strike is quite substantial and difficult to measure in laboratory testing. Therefore, one must carefully evaluate all potential and/or avoided injuries when considering the overall safety provided by one particular form of glazing compared to another. In order to set the stage for the rest of the paper, it is important to briefly define a few terms as they are used here. A “Primary” impact is defined here as when there is direct glazing contact between the occupant and glazing.“Secondary” impact is defined as any occupant impact that is only possible when there is glazing breakage. The testing results revealed a number of significant trends. Based on the tests conducted in this study, the Polycarbonate glazing did not result in any major fractures due to the initial impact event in any of the test cases. Secondly, based on the testing, it has been shown that the impact injury potential of the Polycarbonate glazing appears to be no greater than other interior components of the vehicle. This is based upon film and data analysis in which contact between the occupant and glazing and other surfaces was studied. Overall, the results of this testing indicate that there does not appear to be an added safety risk with Polycarbonate glazing when all the facets of occupant injury potential are considered, and, in addition, there may be a significant safety benefit in the form of occupant ejection containment."
Locking Actuators Today and Beyond,"Hydraulic actuators with internal mechanical locks are attractive when safe repeatable positioning is required along with insensitivity to load and hydraulic pressure variations. Internal locking designs generally offer a lighter, smaller, better protected solution than external locks for applications such as: landing gear, doors, highlift devices, inlet/exhaust geometry control, and armament positioning. The evolution of higher pressure hydraulic systems imposes design challenges because of smaller areas, higher stresses, and high release loads. This paper looks at the experience of one supplier of locking actuators, Dowty Decoto, Inc. (DDI), and at the technology that is, and will be, required to provide the industry with functional, reliable locking actuators."
A Consideration Of Wind Noise Reduction By Air Flow Control,"The relation between the wind noise level at high speed cruising and the vehicle body shape was studied. The wind noise level in the vehicle depends on the external aerodynamic noise and the noise isolation characteristic of the weatherstrip, body panel and so on. In order to reduce the wind noise level; the modification of the body shape is an important Batter. Based on model experiments, it is shown that the aerodynamic noise is generated mainly on the front door windshield glass and its level is effected by the air flow around front pillar. As the aerodynamic noise is induced by the velocity or pressure fluctuation of air flow, the relationships among the front body shape, the air flow fluctuation and the aerodynamic noise are described analytically. The results were applied to the improvement of design of the production vehicles."
Evaluation of Composite Components on the Bell 206L and Sikorsky S-76 Helicopter,"Progress on two programs to evaluate structural composite components in flight service on Bell 206L and Sikorsky S-76 commercial helicopters is described. Forty ship sets of composite components that include the litter door, baggage door, forward fairing, and vertical fin have been installed on Bell Model 206L helicopters that are operating in widely different climates. Component installation started in 1981 and selected components are being removed and tested at prescribed intervals over a 10-year evaluation. Four horizontal stabilizers and ten tail rotor spars that are production components on the S-76 helicopter are being tested after prescribed periods of service to determine the effects of the operating environment on their performance. Concurrent with the flight evaluation, materials used to fabricate the components are being exposed in ground racks and tested at specified intervals to determine the effects of outdoor environments. In this paper, results achieved from 73,000 hours of accumulated service on the 206L components and 50,000 hours on the S-76 components are reported. Six ship sets of 206L components have been removed and tested. Results of 5 years of ground exposure of materials used to fabricate the 206L components are presented. Results of tests on three S-76 horizontal stabilizers and seven tail rotor spars are presented. Panels of material used to fabricate the S-76 components that were exposed for 4 years have been tested and results are presented."
Automotive Mini Disc Changer Mechanism,"A new automotive Mini Disc (MD) changer mechanism has been developed which fits a 1 DIN size chassis. This mechanism, mainly consisting of a disc change mechanism and an anti-vibration mechanism employing a floating disc drive unit system, offers a high vibration resistance, quick disc change capability and a size small enough to set a unit in an instrumental panel (I/P)."
"ITS, A New Restraint System for Side Impact Protection","The Inflatable Tubular Structure (ITS) is a safety system intended to provide head protection during side-impact car accidents. The ITS is an inflatable device fixed at two points; at the front end, to the A-pillar, and at the aft end, to the roof rail behind the B-pillar. It is stowed over the side window under the trim of the A-pillar and the headliner. At one end, a gas generator is electrically connected to the side-impact crash-sensing system which inflates the ITS when needed. The ITS is fabricated in a unique way so that, upon inflation, its diameter greatly increases and its length correspondingly decreases. This causes the ITS to pull itself out of its stored location over the side window into a straight line between its anchor points. The ITS thereby forms a taut semi-rigid structural member across the window opening. The ITS is brought to a pressure higher than an air bag, and is unvented so that, even upon the cooling of the gas, it retains its position independent of window glass support to provide protection in secondary collisions and rollovers."
Study of Whistles with a Generic Sidebranch,"The coupling of shear layer instabilities with the acoustic resonances at the interface of two ducts, a main duct and a connecting sidebranch, leads to whistle noise. The present study investigates experimentally the mechanism of such pure tone noise. A generic sidebranch adapter is fabricated to allow for: (1) the ability to mount downstream of the throttle body in the induction system of a production engine; (2) the adjustment of sidebranch length; and (3) the changes in the diameter of the branch duct. Experiments are conducted both in a flow facility and an engine dynamometer facility for the same set of flow rates. The correlation of the whistle noise between these two facilities is examined in terms of frequency and the dimensionless numbers, including Strouhal and Mach."
Adaptive Camouflage,"Lightweight optoelectronic systems built around advanced image sensors and display panels have been proposed for making selected objects appear nearly transparent and thus effectively invisible. These systems are denoted ""adaptive camouflage"" because unlike traditional camouflage, they would generate displays that would change in response to changing scenes and lighting conditions."
E-BEAM Treatment of Organically Contaminated Water,"Energetic electrons injected into water abundantly create short-lived radicals that initiate rapid reactions. This leads to the break-up of organic contaminants into harmless products. The process works without catalyst (or other consumables) at ambient temperature and pressure. It is highly energy-efficient. We discuss preliminary results concerning removal of trichloro-ethylene, chloroform, benzene, and toluene using an electron beam (E-BEAM) system. On the basis of these results, we review the development of a compact E-BEAM system that can be used in space inhabitation and long-term space travel. Portability is achieved by using a relatively low beam energy, ~250 keV. We discuss newly available electron transparent windows, the development of a high-efficiency accelerator and power supply that control the power consumption to a level acceptable by NASA standards."
A Semi-Empirical Approach for Modeling Greenhouse Surface Wind Noise,"A CAE procedure for modeling the aerodynamic excitation of greenhouse surface vibration and its reradiation as noise is described. The procedure begins with a description of the steady flow over the surfaces. This is used as a basis for estimating the spatially varying unsteady pressure loading. The approach is semi-empirical, utilizing normalized pressure data collected through wind tunnel testing of production vehicles. The unsteady pressures are utilized within a normal mode analysis to predict vibration of the greenhouse panels. Interior noise associated with the panel vibration is estimated from a statistical energy analysis model. We show that contributions of multiple surfaces can be significant."
Booming Noise Analysis in a Passenger Car Using a Hybrid-Integrated Approach,"A hybrid-integrated approach is presented to analyze the structure-borne booming noise in a passenger car. We identify the critical noise transfer path from the engine to the target by the transfer path analysis. However, it does not give the answer for why the noise transfer function is so high at that path. Therefore, an integrated approach which applies the analysis tools systematically is presented. The running mode analysis gives us the operating motion of each component in the body structure. However, there is no evidence that the components that vibrate severely are the sources of this problem. The modal characteristics from the structural modal test enable us to describe the real motion of the body completely in terms of the structural modes. Similarly, the acoustic modal characteristics from the acoustic modal analysis describe the fundamental behavior of the cabin cavity. The introduction of the experimental running mode data of the structure to the acoustic finite element model makes the hybrid analysis possible. Through the structural and the acoustic modal analysis, we verify the mode that contributes to the booming noise. The panel contribution analysis points out the components that have the greatest influence on the booming noise. The modification of the body based on the results of the hybrid-integrated approach results in the great decrease of the noise level."
Development of Vehicle Underbody Acoustic Holography,Acoustic holography is adopted in identifying the noise sources of a vehicle's underbody. Wind noise from a vehicle's underbody accounts for a large portion of the overall noise level due to the complex flow structure. Current study presents the development process of acoustic holography in the vehicle underbody. Difficulties associated with using acoustic holography as well as the method to eliminate the effect of sound reflection will be addressed.
Experimental and Hybrid Modeling of the Medium Frequency Behaviour of Car Panels,"This paper discusses an approach to identify critical car panels and to derive detailed experimental models for these critical panels. The research was conducted in the framework of the Brite/Euram project SALOME and the EUREKA project HOLOMODAL. The panel identification method is based on a numerical or experimental contribution analysis, assessing the partial noise contributions of individual panels to the interior noise. The second step in the approach consists of the derivation of detailed modal analysis models for the critical panels. A novel Electronic Speckle Pattern Interferometry (ESPI) system was developed, and integrated in a classical CAE system. The components of this system are briefly reviewed, and their application to several industrial cases is shown."
Plastic Product Implementaion into Production -Steps from Concepts to Production Reality,The high temperatures associated with paint curing of automobiles fenders causes dimensional variation at the door and hood areas. This paper details the experimental techniques used to study the dimensional changes in fenders after they are processed and assembled “online”. Specific dimensional changes are presented and recommendations for computer-aided -engineering predictions are enumerated. Current work to reduce dimensional variations is described.
Evaluation Methodologies for Automobile Side Impact Development,"A comprehensive strategy for applying quasi-static and dynamic tests in the development of automobile side impact protection systems is presented. The approach is geared towards providing an understanding of how vehicle components relate to occupant protection as measured by the FMVSS 214 dynamic side impact test. These test methods are viewed as being complimentary, rather than competitive, tools to be employed in the overall strategy. The approach begins with obtaining detailed data from an FMVSS 214 dynamic test. Additional instrumentation is required so that the results of the test can be used to form the basis for setting conditions for subsequent quasi-static and dynamic tests. The Composite Test Procedure (CTP) is an integral part of the process. As described here, the CTP can be conducted under three different methods; three step procedure, continuous computer control, and continuous manual control. The principal value of the CTP method is to obtain spatial relationships within the door structure, overall force-deflection properties of the vehicle body structure, and input for a simplified, linear spring mass model to represent the FMVSS 214 dynamic test. Door structures are tested to provide a preliminary evaluation of door modifications, including both structure and trim panel, without resorting to full vehicle body development and build. The methods for door tests include both quasi-static, where the door structure and trim panel are evaluated, and dynamic (sled), where door trim panels are evaluated. Results obtained from these component tests can be related to full scale crash testing through mathematical modelling. The complimentary nature of these test methods is then discussed relative to improving performance in an FMVSS 214 dynamic test. A flow chart showing the relationship to a complete vehicle development program is presented and discussed."
Transient Vibration Analysis During the Door Closing by Using the Laser Holography Method,"The door closing sound is one of the important quality of a vehicle, and it is useful to study the improvement method of closing sound. As a step to clarify the relationship between the door structure and closing sound, it is attempted to correlate the formation of closing sound with the vibration, and explained that the effect of structural modification aimed to improve the closing sound from the viewpoint of vibration. First, the formation process of the vibration during the door closing is clarified through the analysis method of transient vibration using the pulse laser holography. And the quality of closing sound are evaluated based on the time historical fluctuation of frequency characteristics. Next, the correlation between the closing vibration and sound are studied, and for the case of that the closing sound are changed by the structural modification, the correlation are confirmed."
The Corrosion Resistance of Organic Composite-Coated Steel Sheets,"In order to investigate the corrosion resistance of organic composite-coated steel sheets ( OCS ) in a real automotive environment, many kinds of corrosion tests were performed on test pieces and real automotive doors. Tests with a corrosive solution including iron rust were introduced to simulate the real corrosive environment of automotive doors. The relationship between the components of OCS and the corrosion resistance in the rust-including tests was examined. In addition, electrochemical studies were performed. Results indicate OCS has much better corrosion resistance than plated steel sheets with heavier coating weight in all tests. OCS shows excellent corrosion resistance in rust-free corrosive solution, however, some types of OCS do have corrosion concerns in rust-including tests. It became clear that these OCS types have an organic coating with lower cross-linking. With respect to the components of lower cross-linking OCS, Chromate coating has little effect on corrosion resistance in rust-including solution. On the other hand, an organic coating with higher cross-linking shows remarkable improvement of corrosion resistance in rust-including test solutions. Therefore, it is likely that thin organic coatings are susceptible to damage by rust including test solution. Electrochemical measurement actually shows that impedance of OCS after exposing in rust-including solution is lower than before exposing. Consequently, the rust-including tests did simulate the real automotive corrosive environment. It is important to use a proper organic coating with high resistance against rust, because rust exists in real automotive corrosive environments."
Perforation Corrosion of Automobiles - Field Car and Laboratory Investigation,"In order to clarify the effect of design and materials of the hem as well as the climatic factors on perforation corrosion of the automobile doors, field car and laboratory investigation has been carried out Field car investigation revealed that corrosion of the hem can be minimized by using two side galvanized steel plus adhesives. The ratio of wet/dry environment was evaluated in laboratory on hemmed sample, and it was found that the design of the hem in conjunction with the various wet/dry ratio affected the corrosion rate differently."
Flexvalve: An Innovation in Air Flow Control,"This paper describes a flexible-film bladder, mode door. An air line is attached directly to the flexible valve through the mode housing or air duct for vacuum or positive pressure actuation. This technology addresses the need for more compact designs, part reduction and weight savings. It is designed to replace current mode valve doors, actuators and associated brackets. The propounded benefits of this design are outlined along with design considerations and part/system validation testing."
Estimation of the Noise and Vibration Response in a Tractor Cabin Using Statistical Energy Analysis,"The purpose of this paper is to establish a method of predicting the noise and vibration of tractor cabins in the engine-idling state by using Statistical Energy Analysis (SEA). At first, an analytical model of a tractor cabin is constructed, and power flow equations are formulated for the tractor cabin. To solve these equations, SEA parameters are estimated experimentally and analytically. These parameters are the modal density, loss factor, coupling loss factor, and input power. With these parameters, the noise and vibration responses of the tractor cabin are calculated. Good agreements are found between the analytical and experimental data."
Maturing Fiber Reinforced Thermoplastic Technology for Automobile Body Structural Applications,"With the increasing emphasis on fuel efficiency and environmentally friendly vehicles, much effort is being directed by the auto industry to develop efficient, lightweight and alternative-powered vehicles. One of the ongoing research programs at DaimlerChrysler's Liberty and Technical Affairs is not only aimed at reducing the overall weight of the automobile body structure, but also reducing the cost of manufacturing it. In addition, an automobile body structure needs to meet the requirements of noise, vibration and harshness (NVH), durability, crashworthiness and recyclability. The objective of this paper is to provide a review of the ongoing research and development activities leading to an automobile body structure that meets the above objectives. The paper highlights the many different technology development challenges faced during the process. Discussions of the choice of material systems, injection molding of very large body structural panels using these material systems, their applications to different products, cost implications and supplier issues are included in this paper."
Rapid Development and Deployment of Dynamic Graphical Human-Machine Interfaces Within Automotive Environments,"Emerging ‘glass’ displays make possible the benefits of Super Integration (SI) including weight, volume, and part count reductions as well as quality, reliability, serviceability, NVH, and manufacturability improvements [1]. This paper discusses an alternative to the hand-coding of displays aimed at facilitating the iterative development of Human-Machine Interfaces (HMIs) and the rapid generation of small-footprint, high-performance embeddable code for use in development, testing, simulation, documentation, and actual product environments. The process of code generation and rehosting at the heart of this technology will be described as will the architecture of the resulting software. Implementation experience will also be cited."
Optimizing Sensor and Actuator Arrays for ASAC Noise Control,"This paper summarizes the development of an approach to optimizing the locations for arrays of sensors and actuators in active noise control systems. A type of directed combinatorial search, called Tabu Search, is used to select an optimal configuration from a much larger set of candidate locations. The benefit of using an optimized set is demonstrated. The importance of limiting actuator forces to realistic levels when evaluating the cost function is discussed. Results of flight testing an optimized system are presented. Although the technique has been applied primarily to Active Structural Acoustic Control systems, it can be adapted for use in other active noise control implementations."
Intrusion Resistance Test Development for Automotive Glazing,"Consumers worldwide are demanding intrusion resistant automotive glazing. In response, carmakers are installing laminated side and rear glazing for enhanced protection. To insure enhanced protective glass (EPG) performance, a test is being developed to measure intrusion resistance in three simulated break-in modes. The three test modes are: glazing point attack; exterior impacts to penetrate the glazing or separate it from the vehicle body; continuous force to pull the glazing out of the body. The strength of the glazing and the strength of the glazing/vehicle attachment are both important for intrusion resistance. An intrusion resistance test method is recommended."
Establishment of Stamping Process Windows,"A stamping process window is a set of ranges of the critical input variables in the process. Quality parts can be produced only if all of these variables fall within their respective ranges. To achieve this, the window has to be wide enough and the process properly located within the window. In this paper, various input variables in stamping are examined and the variables that have to be strictly controlled are identified. The establishment, transfer, adjustment, protection, deterioration and re-opening of stamping process windows are described. Examples from production are presented."
Measurement and Evaluation of Aerodynamic Noise,"Recently, aerodynamic noise which originates in the flow of the body surroundings is actualized as a main cause of an automobile interior noise when running at high speed, because engine, power train and tire noise have been greatly decreased. Along with it, the measurement technology for the phenomenon elucidation and the evaluation has been demanded to decrease aerodynamic noise. In this paper, typical measurement examples of aerodynamic noise are introduced. These measurement technologies can be classified, and arranged to four types of measurements, which are flow, external noise, transmission psth and interior noise. This paper presents how the advancement of these measurement technologies has contributed to the aerodynamic noise elucidation. Moreover, the latest evaluation method of aerodynamic noise and the trend in the future to the demand of customer's many topics are introduced."
Review of Aerodynamic Noise Prediction Using CFD,"Recently, computational fluid dynamics (CFD) has made great progress. This paper reviews published papers on aerodynamic noise simulated by CFD and studies to what level CFD can predict aerodynamic noise for basic models and for applied models of automobiles. Based on noise generation mechanisms, aerodynamic noise is basically classified into two types, that is, noise induced by two-dimensional flow and by three-dimensional flow. As typical examples of noise generated by two-dimensional flow, wind throb at opened sliding roof, edge tone at the end of liftgate and aeolian tone generated by a cylindrical antenna are simulated by several computational schemes. As typical examples of three-dimensional flow, noise generated by A-pillar longitudinal vortex and noise from a side view mirror are computed by using a wing model and a actual vehicle, respectively. Noise by two-dimensional flow can be almost estimated whereas noise by three-dimensional flow cannot be predicted at sufficient accuracy especially in high frequency range. In order to predict noise with high accuracy it is necessary to improve computational techniques, based on noise data obtained by a carefully conducted wind-tunnel experiment which studies basic flow patterns with simple models."
Life-Cycle Optimization of Car Components,"The environmental impact of the automobile and its components is of growing importance not only in public debates but also in the complex decision making process regarding future car concepts. To calculate the environmental compatibility of car components BMW has developed various quantifying instruments and a holistic Life-Cycle Analysis (LCA) approach. The development phase significantly affects the entire life-cycle of a product. Suitable design criteria, recycling requirements and in-house standards have therefore been developed and established. One of the most important objectives in optimizing the environmental compatibility of the automobile is the realization of intelligent lightweight concepts. This means one has to find the most appropriate solution in terms of ecology and economy. Due to modern development processes car manufacturers and their suppliers have to intensify their cooperation also in this area. This paper presents some results of the cooperation between BMW and Hydro Aluminium for optimizing the life-cycle of various lightweight door concepts. Some general conclusions and „lightweight laws” have been deduced therefrom. This integrated life - cycle approach on a component base has the potential to become a practical development tool for managing the additional conflict of objectives with a view to the life-cycle ecology and economy of the automobile."
Low Frequency Design Considerations for Automotive Audio Systems,"The automobile interior is a challenging environment for the audio system designer. Yet, the literature related to automotive acoustics is sparse compared to the amount of published information on the acoustics of rooms and performance spaces. This paper addresses three areas of importance to the design of high fidelity autosound systems. First, it is difficult to accurately predict the nature of the listening acoustics in a car at low frequencies because complex interior geometries make mode calculations almost impossible. At the same time, the cabin interior introduces acoustic gain in the first three octaves of musical reproduction. Secondly, the car environment is subject to constantly changing levels of so-called road noise that mask musical material at low frequencies. Finally, a simplified model is proposed for the characterization of the car door as a loudspeaker enclosure. Measurement data are presented to illustrate the nature of low frequency gain in automobile cabins and to evaluate the feasibility of the proposed enclosure model."
High Performance Executive Transport Design Employing Twin Oblique Lifting Surfaces,"This paper presents a new Trans-Atlantic high performance executive transport suitability equipped to offer accommodation for 19 first class passengers. The unique feature of this conceptual design is application of Twin Oblique Lifting Surfaces or TOLS configuration. Minimum goals for the design included: similar maximum takeoff gross weight; satisfactory field performance; good stalling characteristics; and, competitive fuel burn qualities at high-transonic and low-supersonic speeds, i.e. M0.90–1.20, compared to contemporary M0.75–0.85 large and super-large business jets. The vehicle is to be powered by two medium by-pass derivative engines based on the BMW-Rolls Royce BR715 in an effort to maximize the likelihood of availability, ensure adequate en route performance efficiency and fulfillment of yet to be ratified Stage 4 noise compliance requirements."
Assessment of a Vehicle Concept Finite-Element Model for Predicting Structural Vibration,"A vehicle concept finite-element model is experimentally assessed for predicting structural vibration to 50 Hz. The vehicle concept model represents the body structure with a coarse mesh of plate and beam elements, while the suspension and powertrain are modeled with a coarse mesh of rigid-links, beams, and lumped mass, damping, and stiffness elements. Comparisons are made between the predicted and measured frequency-response-functions (FRFs) and modes of (a) the body-in-white, (b) the trimmed body, and (c) the full vehicle. For the full vehicle, the comparisons are with a comprehensive set of measured FRFs from 63 tests of nominally identical vehicles that demonstrate the vehicle-to-vehicle variability of the measured FRF response."
"A Method and Apparatus for Generating Full Vehicle Roof System Rain Noise for the Purpose of Development, Benchmarking and Interior Noise Performance Measurement","The direct excitation of a vehicle roof system by a repeatable method and the corresponding interior sound pressure level generated by that excitation can be a key characteristic of the total interior acoustic signature of a vehicle. After nine years of work and five design iterations, a test method and apparatus has been developed that exposes a vehicle to a repeatable and measurable artificial rain excitation. The test apparatus, method and performance data are reviewed. Performance data is shown for several different vehicles and roof systems."
Feasibility of Using Acoustic Room Models and Measured Sound Power to Estimate Vehicle Interior Noise,"In this paper, interior noise of a heavy commercial truck was modeled with the room equation. This approach assumed that large truck cabins may be adequately modeled as a practical room as is done in architectural acoustics, where ray theory and statistical concepts are suitable, and where application of complicated wave theory may not be necessary. This simplifies computational requirements, making a semi-empirical scheme useful for timely product development. This study employed sound power measurements at thirty-four surface patches encompassing the interior cabin boundary. Each surface-patch constituted an individual interior noise source. Predicted and measured results correlated well, demonstrating the capability to estimate driver-position noise level from predicted periphery sound intensity changes."
New Developments on Glazings,"Increase of size and bending of glazings, and general improvements concerning NVH, has made of glazings one of the weak points to be treated. No specific acoustic solutions existed. First question was to determine exactly concerning which problems glazings were involved, and then what and how solutions could be found. Main problems were found concerning booming noise, transmission of airborne external noise and aerodynamic noise. To dispose of good specifications concerning products, simulations had to be done and validated: finite elements code for low frequency behavior (booming and airborne), SEA and modal superposition concerning medium and high frequency (aerodynamic and airborne). This was done for monolithic and laminated glass with their shape, free-free and taking into account boundary conditions: glues, extrusion, encapsulation. The way it has been done is presented: measurements of the characteristics of components (interlayers, glues), use of FEM and FEM-BEM methods from CAD shapes, use of SEA. Validations are also presented. Problems to solve were mostly coupling between windshield eigenmodes and internal modes of the cavity excited by the engine (low frequency), and whistling due to coincidence frequency of glass concerning mostly aerodynamic noise. Solutions are found by using specific interlayer instead of standard PVB within the laminated glass, or by improving boundary conditions by using specific shapes and/or material of the joint, first defined by a specific software. Psychoacoustic criteria are used to optimize the solutions. Shape influence is also studied. Some specific studies concerning both problems are presented. Some glass solutions now exist to reduce NVH problems within cars, and/or to compensate reduction of weight, which is one main topic of car industry."
Noise and Vibration Reduction Technology in Hybrid Vehicle Development,"The world's first mass production gasoline hybrid passenger car, the “Prius”, was introduced into the Japanese market in 1997. By the time it was introduced into the American and European markets in Mid-2000, its fuel consumption and exhaust emissions had been further improved while achieving superior NV performance compared with conventional vehicles with 1.5-liter engines even in these competitive markets. This paper describes NV reduction technology for problems peculiar to the hybrid vehicle such as engine start/stop vibration, drone noise and vibration at low engine speed and motor/generator noise and vibration. It also compares the overall NV performance of the hybrid vehicle with conventional gasoline engine vehicles."
"Automatic Detection of Buzz, Squeak and Rattle Events","In the world of BSR (Buzz, Squeak and Rattle) testing, there is a high level of sophistication regarding the test machines employed to excite the items under test as well as the techniques used to ensure that the test is representative of real-life operating conditions. However, the object of the measurements, i.e., the identification of transient acoustic events classified as Buzz, Squeak or Rattle, is mostly a subjective procedure with classification in terms of Sound Pressure Level in dB(A) or Stationary Loudness. These “standard” metrics have proven, in general, unreliable in assessing the importance of individual transient events, and inappropriate to describe the vehicle signature from a BSR standpoint. This paper presents a methodology that has been developed for the BSR test of a vehicle using a road simulator to: 1 Demonstrate the feasibility of an automated system of detection of BSR events that can replace the “subjective” detection 2 To establish “vehicle BSR” indices that can be used to assess design targets and specifications."
Vehicle Wind Noise Analysis Using a SEA Model with Measured Source Levels,A series of tests have been performed on a production vehicle to determine the characteristics of the external turbulent flow field in wind tunnel and road conditions. Empirical formulas are developed to use the measured data as source levels for a Statistical Energy Analysis (SEA) model of the vehicle structural and acoustical responses. Exterior turbulent flow and acoustical subsystems are used to receive power from the source excitations. This allows for both the magnitudes and wavelengths of the exterior excitations to be taken into account - a necessary condition for consistently accurate results. Comparisons of measured and calculated interior sound levels show good correlation.
Condition Monitoring of a Gear Box Using Vibration and Acoustic Emission Based Artificial Neural Network,"The objective of this study is to investigate and develop an Artificial Neural Network approach based on vibration and AE signals for the detection, and characterization of wear, damage, and malfunction of an experimental gearbox. Five artificial defects were introduced to the gearbox and these are; (1) tooth face wear, (2) full tooth breakage (missing tooth), (3) clearance or backlash, (5) axial gear looseness, and (5) single internal bearing race wear. The signals, collected from extensive experimentation, were analyzed using time-frequency harmonic wavelet transform, Power Spectral Density (PSD), and four statistical measures of the time domain that captured the salient features of the vibration and AE signals. The results of the time and frequency domain analysis were used in developing a neural network-based estimator for on-line monitoring of gearbox operational condition. The results strongly suggest that vibration and acoustic emission (AE) signals have tremendous promise for machine health monitoring and diagnostics. The proposed technique can be adopted for on-line monitoring of power train and Engine systems, which could be a second phase of this project."
A Comparison of NVH Treatments for Vehicle Floorpan Applications,"Under the constraints of improved vehicle refinement, automotive OEMs are challenged to improve vehicle noise, vibration and harshness (NVH) characteristics, reduce vehicle weight, and streamline manufacturing and assembly processes. In support of these objectives, alternate methods of vehicle noise control are being investigated. This paper will address one area where alternate material strategies are being investigated to meet these requirements. Floorpan damping treatments are a primary component of the overall vehicle noise package. This paper will investigate three floorpan damping treatments. Comparisons will be made between asphaltic melt sheets, constrained layer dampers, and spray-on dampers. Performance of these treatments will be measured using laboratory methods and will feature a case study using a Body-In-White (BIW) to demonstrate performance of the different materials."
The Application of Direct Body Excitation Toward Developing a Full Vehicle Objective Squeak and Rattle Metric,"In order to engineer Squeak & Rattle (S&R) free vehicles it is essential to develop an objective measurement method to compare and correlate with customer satisfaction and subjective S&R assessments. Three methods for exciting S&Rs -type surfaces. Excitation methods evaluated were road tests over S&R surfaces, road simulators, and direct body excitation (DBE). The principle of DBE involves using electromagnetic shakers to induce controlled, road-measured vibration into the body, bypassing the tire patch and suspension. DBE is a promising technology for making objective measurements because it is extremely quiet (test equipment noise does not mask S&Rs), while meeting other project goals. While DBE is limited in exposing S&Rs caused by body twist and suspension noises, advantages include higher frequency energy owing to electro-dynamic shakers, continuous random excitation, lower capital cost, mobility, and safety. Results show that almost all S&R issues found on the road and simulator are found on DBE. In many cases additional issues are discovered because of the lack of background noise. Initial data tends to show that using DBE to excite interior S&Rs is preferable to actual roads or to 4-post road simulators for making objective measurements."
Use of Layered Media for Noise Abatement in Automotive Interiors: A Balanced Approach,"Concepts for dual density materials for usage as absorbers and decouplers are based on well-established layered media principles and have been applied for many years in non-automotive applications. Balancing the mass, air flow resistance, and thickness allows for improved noise attenuation in the low to mid frequency range which is of particular interest for automotive NVH management. Using these principles, products were tuned via mass and airflow resistance to reduce noise levels while also significantly reducing mass. Validation in various vehicles confirmed that up to a 55% reduction of a sound package's mass is possible. The considerable weight reductions of dash insulators and carpet systems are possible at the same times as the sound level in the vehicle interior is at least maintained and frequently improved. Product designs utilize non-woven fabrics and vertically and or horizontally lapped fibers to provide excellent fit and finish at low weight in an all-thermoplastic, recyclable product. Here, product development is described, which utilized computer modeling to provide a balance between transmission loss and absorption properties. Test results showing the effects of various properties on sound transmission loss and normal incidence absorption as well as in vehicle performance are given."
“Digital Prototype” Simulations to Achieve Vehicle Level NVH Targets in the Presence of Uncertainties,"“Digital Prototype” simulations have been used at DaimlerChrysler to achieve vehicle level NVH objectives. The effectiveness of these simulations to guide the design when faced with vehicle parameter uncertainties is discussed. These uncertainties include, but are not limited to, material properties, material gauges, damping, structural geometry, loads, boundary conditions and weld integrity. Manufacturing and assembly processes introduce variations in the nominal values of these parameters resulting in a scatter of vehicle level NVH simulation responses. An example of a high frequency NVH concern will be studied and modified to arrive at robust design guidance when faced with uncertainty. The validity of a “deterministic digital prototype” simulation model and its relevant role as a “trend predictor” rather than “absolute predictor” tool in guiding the design is also discussed."
Development and Experimental Evaluation of a Vehicle Structural-Acoustic Trimmed-Body Model,A structural-acoustic finite-element model of an automobile trimmed-body is developed and experimentally evaluated for predicting body vibration and interior noise for frequencies up to 200 Hz. The structural-acoustic model is developed by coupling finite element models of trimmed-body structure and the passenger-compartment acoustic cavity. Frequency-response-function measurements of the structural vibration and interior acoustic response for shaker excitation of a trimmed body are used to assess the accuracy of the structural-acoustic model.
Active Noise Control and Sound Quality Design in Motor Vehicles,"Interior noise in motor vehicles is essentially influenced by the engine which may contribute via both, structural and acoustic transmission paths. This engine related interior noise components may be controlled deliberately by active control measures without changing any source or transfer paths characteristics. Besides attenuating dominant noise components, the approach may equally be used to optimise interior sounds with respect to sound quality. Based on general considerations how active noise and vibration control measures may effect subjective criteria, the paper gives examples how different, sometimes extremely contrasting noise characteristics may be realised in a given car."
Safety Related Testing and Results of Polycarbonate and Tempered Glass Non-Windshield Glazing Applications,"This paper presents results from a series of tests that address safety related issues concerning vehicle glazing. These issues include occupant containment, head impact injury, neck injuries, fracture modes, and laceration. Component-level and full vehicle crash tests of standard and polycarbonate non-windshield glazing were conducted. The tests were conducted as part of a study to demonstrate that there is no decrease in the safety benefits offered by polycarbonate glazing when compared to current glazing. Readers of this paper will gain a broader understanding of the tests that are typically conducted for glazing evaluation from a safety perspective, as well as gain insight into the meaning of the results."
Package Tray Optimization Using Experimental and Analytical Techniques,The area in the neighborhood of the package tray can be a significant path for road noise and exhaust noise. Air extraction routes and loudspeakers add to the difficulty of effective system design. A variety of designs were prototyped and their transmission loss measured in a standard SAE J1400 sound transmission loss suite. The performance of the various designs was compared to an untrimmed piece of sheet metal with embedded air extraction holes. The addition of trim added from 1 dB to 14 dB to the transmission loss. Statistical energy analysis (SEA) models of a variety of package tray systems will also be shown. Both of these techniques can provide design guidance at an early stage of vehicle program development.
THE WINDOWBAG: AN INNOVATION IN SIDE IMPACT PROTECTION,A new additional airbag system will provide enhanced protection in side impact collisions. The so - called Window Bag will be installed in some Mercedes cars beginning with the E-Class Sedan for the MY99 and in the new S - Class.
Dispelling the Misconceptions about Side Impact Protection,"Those responsible for designing cars to meet the European Side Impact Test Procedure are tending to find it more difficult than they originally expected. The conventional wisdom has been that strengthening the car and providing padding should improve protection. However, many are finding that attempts to meet the test requirements, by reducing door intrusion or intrusion velocity, are proving ineffective. Extensive research carried out at TRL has helped to explain why strengthening the car side is ineffective. It has also given an insight into the side impact injury process and provided design guidelines which can be used to ensure that cars meet the test requirements. The difficulties experienced by car designers may explain why alternative test procedures have been suggested and proposals have been made which would reduce the severity and effectiveness of the full scale test procedure. This paper reports on the extensive research carried out by TRL, explains why the conventional wisdom was flawed, details the design guidelines and provides reasons why the beneficial use of quasi-static and component testing of doors is likely to be limited."
The Application of the Simulation Techniques to Reduce the Noise and Vibration in Vehicle Development,"An overview of the analytical noise and vibration simulations performed to support the design and development of the passenger car was presented. Analytical models of the structural vehicle and acoustic cavity were developed, and several simulations related to the NVH were performed in the prototype development stage. All of the simulations were performed to minimize development time as well as to optimize the cost, weight, and performance of the NVH and the maximum frequency of these analyses is 200 Hz. The modal analysis and design sensitivity analysis of the body-in-white was performed to minimize the mass while maintaining the body stiffness by using the concept model and detailed model. Most of the subsystems such as engine mount, steering, suspension and exhaust pipe system were analyzed respectively and in the combined system for the design studies of the idle shake and high-speed wheel shake analysis. Structure-borne noise due to both road-induced vibration and engine vibration were considered. Most of the analysis was performed before prototype vehicles were tested to make the design implementation. The vehicle design cycle was reduced and the noise and vibration quality was improved by application of these simulations."
CUPOLA Environmental Control System,"The Cupola Environmental Control System (ECS) has the task to ensure the required Cupola internal environment using passive and active control means, in response to the relevant applicable Cupola requirements. The ECS is subdivided into a Thermal Control Subsystem (TCS) and an Environmental & Life Control Subsystem (ECLS). The particular characteristics of Cupola design requires a non standard way to control the internal environment conditions: TCS controls the Cupola primary structures through an High Temperature water Loop (HTL) avoiding shell heaters necessity in the cold cases and representing also an heat sink for the windows assy in the hot cases; ECLS design realizes the air distribution inside the cabin volume using the gap existing between the primary and secondary structure without dedicated ducts. The major ECS functions are: to control the primary and secondary structure temperatures, to homogenize the structural walls temperature using the HTL, to prevent the condensate formation inside the Cupola, to control the Cupola Internal Pressure, to guarantee a fire protection inside Cupola, to define an air distribution concept, to support a safe, habitable, shirtsleeve environment inside the Cupola. The paper describes also the extensive analysis campaign planned to support the Cupola TCS and ECLS design and verification phases."
Subcompact Sport Vehicle Development,"Considering that the sport cars versions are normally derived from medium car segment, the big challenge in this program was to transform one subcompact in a real sport car. With the focus at the consumer that looks for performance and enjoys sporty driving in conjunction with project financials and competition data the preliminary content was established together with all involved areas, Marketing, Finance, Manufacturing and Quality. Based on the items that indicate high performance, the items considered mandatory or desired by the customer and items detected by Quality research including internal indicators and external indicators, ICCD (Intensified Customer Concern Definition) and TGW (Things Going Wrong), the content was developed in three main directions towards Customer Satisfaction, I) Characterize the vehicle as a high performance car, a pure sport car with outstanding performance for power train, suspensions and brakes mainly. II) Identify the items considered mandatory by the customer for a sport car, for example. Alloy wheels, low profile tires, spoiler and rocker panel cladding, etc. III) Incorporate Quality and Durability improvements at modified or new systems. As part of the actions included at content the project objectives were established for Performance, Fuel Economy, Noise/Vibration/Harshness, Brakes, etc. These atributes was considered strategic for this product, a real sport car. With content preliminarily defined and the project strategy defined the development started with a timing plan defined with progressive phases until Job#1. The development phases consist in the verification and confirmation of product attributes with attribute and confirmation prototypes with durability and certification tests, resulting at engineering signoff and subsequent phases at production, with the 1st production prove out, and first field evaluation units and consequent production acceleration curve and the start of production."
Comparison of Performance between Several Vehicle Windshield Defrosting and Demisting Mechanisms,"The safety and comfort aspects of passenger cars are significant sales argument and have become a topic of rising importance during the development process of a new car. The objective of this study is to compare the performance of several current model vehicles, highlight the drawbacks of current defrosting/demisting systems and point the way to improved passive mechanisms. The investigation is experimental. The experiments are carried out using full-scale current vehicle models. The results show that the current designs of the defroster nozzle give maximum airflow rates in the vicinity of the lower part of the windshield, which decrease gradually towards the upper parts of the windshield. This hinders and limits the vision of the driver, particularly at the top of the windshield, which can be uncomfortable and indeed dangerous."
Development and Application of an Integrated Dew Point and Glass Temperature Sensor,"With the optimization of HVAC system controls for comfort, air quality and energy efficiency the potential for fogging the glass has increased. To maintain occupant safety, a method to predict when such fogging conditions exist is necessary to be able to execute proactive control corrections to prevent fogging. Windshield fog conditions are predicated on windshield surface temperature, cabin relative humidity and the reference temperature of the humidity sensor. This has driven a joint development project between Delphi Automotive Systems divisions to develop an Integrated Dew Point and Glass Temperature (IDGT) sensor. This sensor is a combination of three elements: a glass temperature sensor, a relative humidity sensor, and a humidity reference temperature sensor. Using this sensor package, the cabin dew point is calculated from the relative humidity and humidity reference temperature for comparison with the windshield glass temperature. When the windshield glass temperature drops to or is below the cabin dew point temperature, fog will form on the windshield. Utilizing this information, a proactive automatic climate control system implements corrections before the occurrence of fogging. This paper discusses the following issues concerning this new technology: Sensor design and development. A comparison between the existing technologies and the new sensor design. Vehicle / system integration of the sensor."
Integration of Fluid Flow Modelling in the Vehicles Renault Development Process,"This paper presents some of Renault's knowhow in modelling aerodynamic flows obtained in an operational environment on development configurations. The methodologies, developed from Navier Stokes equations averaged for turbulence, are used indeed to size openings and body elements, determine positions and optimize the geometry of the various air inlets and outlets, reduce pressure losses in the cab ventilation circuits, improve exchanger efficiency, optimize the underhood architecture devise encapsulation solutions, model windscreen de-icing, reduce aerodynamic noise and improve the understanding of certain physical processes associated with fouling."
Conditions for Incipient Windshield Fogging and Anti-Fog Strategy for Automatic Climate Control,"This paper describes a strategy, suitable for use in a climate control ATC (Automatic Temperature Controller) for predicting the onset or existence of fog (or misting) conditions and automatically taking action to avoid or reduce such conditions. Two variables currently measured by the ATC, cabin air temperature and ambient (outside) temperature are combined with cabin air relative humidity information provided by an additional sensor to allow the calculation of a degree of likelihood of windshield/window fogging. As fogging conditions are approached, a staged alteration of climate control strategy can relieve or even avoid altogether windshield fogging."
42V Design Process,"Demands for new features, increasing electrical loads, and improved fuel-economy are driving development of 42V PowerNets in automobiles. Shorter design cycles, increased complexity and a focus on quality are making robust design processes a strategic advantage for competitive manufacturers. Hardware prototypes are both time-consuming and inadequate for the task of verifying performance over a broad range of operating modes, environmental conditions and part-to-part variations. This paper outlines the use of an advanced design-flow, from idea to manufacturing, for vehicle power systems. It starts with the analysis of different topologies down to the subsystem modeling of a power window system. Finally it integrates everything to a Digital Mock-Up (DMU) and analysis of the entire system. Dynamic interactions among the various supplies, converters and loads are examined. System stability and performance are assessed under normal and extreme operating conditions."
Automotive Glazing: Issues and Trends,"Key current issues and future trends in automotive glazing were identified through extensive interviews of global OEM and supplier engineers. Although the performance of tempered glass has significantly improved, application of laminated glass to side and rear windows is expected to increase globally. Plastic, most notably polycarbonate (PC), glazing is also under development although the material technology has not reached a level for mass application. Incorporating multiple features and functions into glazing is another important technology development area. Needs and acceptance as to new materials and technologies vary by the automaker and the geographic market."
Use of PVB in Laminated Side Glass for Passenger Vehicle Interior Noise Reduction,"Polyvinyl butyral (PVB) is used in laminated side glass on several new vehicles. One of the major benefits of PVB-laminated side glass is the reduction of interior noise. To quantify this benefit, Solutia commissioned NVH testing of an S80® passenger car from Volvo with factory-equipped laminate side glass, comparing that with factory-equipped tempered glass. The noise source was a tractor-trailer truck traveling side-by-side with the vehicle. Significant noise reduction was noted (-2-6 dB in the 2k - 6k Hz range). The dampening characteristics of the PVB laminate interlayer reduced wind noise and greatly reduced traffic noise entering the cabin. A secondary benefit is that the NVH reduction was achieved while lowering the weight of the side glass by 11%. In this paper, results of the S80 vehicle testing will be reviewed and comparisons to conventional tempered glass shown. Also discussed will be OEMs, including Audi and Peugeot, which are marketing this benefit to customers."
Comfort and Durability of Cabin of Commercial Vehicle,"With the opening up of the economy and globalization in India, provision of reliable infrastructure has become a priority area in order to facilitate faster economic growth. The backbone for the economic growth is transportation. In transportation, the commercial vehicle industry plays a lion's role and hence demands urgent attention. One of the neglected areas in the commercial vehicles is its cabin. Driving commercial vehicle in India, is hard and hazardous work lasting for long hours in distant and unknown places of varying environmental conditions. In India, most often, the driver of a commercial vehicle is an employee unlike in developed countries where he is a owner driver. Further, most of the commercial vehicles supplied in India today are drive-away chassis and with the engine in the driver's compartment unlike the built-in cabins abroad. The design of the cab and the compartment of the driver and its comfort which is essential for safe driving, an area left to the whims and fancies of body builders, calls for immediate attention for improvement. This paper details many of the parameters required to be looked into such as space, ergonomic design, noise, vibration, heat, safety features, materials used in the cabin, durability, etc. This paper also compares quantitatively the above parameters between the Indian scenario and advanced design/developed countries, as well as mandatory requirements imposed by Occupational Safety and Health Act (OSHA), Bureau of Motor Carrier Safety (BMCS), Federal Highway Administration, US Department of Transportation, etc. It also suggests recommendations for the improvement of the cab as a work place. This paper also presents a case study on a detailed exercise carried out in characterisation and improvement of the vibration levels and methodology of carrying out vibration durability and structural integrity of the cab design for commercial vehicles."
Automotive Engineering International 2000-09-01,"Improving lightweight vehicle dynamics Bosch engineers used numerical simulation to evaluate vehicle concepts using variable semi-active components, tire specifications, and suspension spring rates. Dr. Reitzle's prescription for Jaguar His vision for the brand is to ""use top-level technology and do so in a very emotional way."" Dual-voltage power networks Lear Automotive EEDS has developed an innovative electrical and electronic architecture to handle future high-power requirements in vehicles. New door closure concepts Bosch and Temic engineers are developing technologies for passive entry, vehicle immobilization, and remote control. TwinCAN: one module for two nodes The ability to use one module to control two CAN nodes provides benefits including reduced hardware and software requirements, improved functionality, and lower CPU load, according to Infineon researchers. Java for telematics Motorola engineers believe the Java framework will allow the secure deployment of infotainment services to the automobile. Car computing device analysis Unique solutions are required to match computer devices to human needs for a safer, more comfortable driving environment. Electricity builds for Convergence 2000 The automotive and electronics worlds are meshing to an ever-greater extent. Convergence 2000 provides a forum in which engineers and related professionals who populate those worlds come together to explore just how ""wired"" the vehicle can become."
Aerospace Engineering 2000-01-01,"Simulation solves C5 cargo door problem Dynamic analysis software allows engineers to solve fatigue-related problems without prototypes. UAV development Although unmanned aerial vehicles (UAVs) have been employed successfully by the U.S. military to date, many development and operational challenges remain for these to become viable alternatives for manned aircraft. Aircraft engine testing: the test tig developer Engineers at Belcan's Advanced Engineering & Technology Division share their insights and experiences on the development of aircraft gas turbine test rigs and stands. This is the first installment of a three-part series on aircraft engine testing. Looking back at factory automation The ability to improve quality while substantially reducing the cost of production and span times is becoming a necessity to complete in today's aerospace industry. Matt Borland, Director of Production Integration on the C-17, Airlift, and Tanker programs, talked about the value that automation presented to the C-17 assembly program."
Structure Borne Sound Transmission Through a Motor Vehicle,"Sound transmission at joints in a motor vehicle is studied using Statistical Energy Analysis. It is shown that transmission at edges of windows can be modelled successfully as transmission past an elastic interlayer. Coupling from the car body to the doors is modelled as transmission across a pin. Corner cross and tee joints between panels are also studied. Measurements were carried out on a motor vehicle using an impulsive noise source and results for acceleration level differences and damping are presented. The measured results are compared with results obtained using a Statistical Energy Analysis model for sound transmission, where only bending wave transmission is considered. Large acceleration level differences are measured and predicted results show good agreement. The results show that Statistical Energy Analysis techniques can be used to study structure borne sound transmission in motor vehicles."
A Multiplexing Communication IC for Automotive Body-Electronic Control,"In the field of automotive body electronic control such as control of door locks, power windows, and wipers, there is a growing need of multiplexing communication to reduce the amount of wire harnesses. To meet this need, we developed a multiplexing communication protocol particularly suited to the body electronic control. Based on the developed protocol, we designed a communication control IC and a simple driver/receiver circuit with a few discrete components. The bus access method of the communication is the CSMA/CD with nondestructive bit arbitration, and its bit rate is 5 kbps. Its transmission media is a single wire. The communication IC has a multiplexing control block and a serial I/O block for an interface with a host CPU. It was fabricated using CMOS technology and has a chip of 2.6mm x 3.0mm in size that contains about 5,000 transistors. The driver/receiver circuit consists of one transistor, one capacitor and several resistors. Therefore, the cost of the circuit is quite low. This paper gives a detailed description of the design specification and features of the communication control IC and the driver/receiver circuit."
The Design Considerations of an Anechoic Chamber,"There are a number of factors that dictate the size, type, and resultant over all cost of a controlled acoustical environment in which measurements can be made accurately and reliably. The type of acoustical environment is generally specified in the appropriate SAE, ISO, ANSI or ASTM standards. The purpose of this paper is to concentrate upon the design considerations of a properly engineered anechoic chamber. Anechoic is defined as “free from echoes or reverberations”. An ideal chamber would contain no reflections of sound from its walls, ceiling, or floor and an acoustical free-field condition would exist. Probably the best testing environment is outside with no boundaries to cause reflections. However, temperature, pressure, humidity, and wind can significantly and unpredictably disturb the uniform radiation of sound waves. In an ideal free-field environment, the inverse square law would function perfectly. This means the sound pressure level from a sound source would decrease six decibels for each doubling of distance from the source. For anechoic chambers to function as required to meet the various standards, a number of acoustical, mechanical, electrical, and aerodynamic considerations apply. This paper is intended to briefly address these considerations which include some, or all, of the following: Test object size Anechoic treatment selection Cut-off frequency Test object noise levels Parent room noise levels Vibration isolation Ventilation system requirements Structural requirements Physical access requirements Lighting and electrical requirements Visual requirements Housekeeping requirements RF shielding requirements"
Fast Determination of Vehicle Sound Level per ISO 5130,"Noise from vehicles is a major contributor to community noise. While at high speed often the pavement-tire interaction may be the predominant source, engine noise may also be significant, especially at low speeds. In some European countries most trucks, autos, and motorcycles must be tested at regular intervals per ISO 5130 (1982) “Acoustics- measurement of noise emitted by stationary vehicles- Survey method.” The standard requires a measure of the maximum emitted exhaust Fast, A-weighted sound level between a given engine RPM and an idle condition. In the past, the RPM has required a significant time to measure since it requires connecting a transducer somewhere in the engine compartment. This paper discusses an instrument that extracts the engine RPM from the acoustic signal at the exhaust, based on different engine types. This eliminates the need for a direct connection and considerably speeds vehicle tests."
Practical Applications of SEA CAE Analysis in Vehicle Sound Package Development,"Vehicle sound package serves two basic functions: general acoustic insulation and local problem treatment. The former is often done at the up-front phase of the vehicle development process, and the latter at the downstream phase when representative prototype hardware becomes available and specific noise problems are identified. This paper examines the goals and key tasks of practical SEA CAE applications in the two phases of the sound package development process. Topics on CAE model requirement, typical analysis applications, and ways to improve the effectiveness of SEA applications to compliment hardware testing are discussed."
Wind Noise and Aerodynamic Drag Optimization of Outside Rear View Mirrors,"Automotive outside rear view mirror shape has become an important consideration in achieving wind noise and aerodynamic performance objectives. This paper describes a two step process used to develop a mirror shape which meets both wind noise and aerodynamic objectives. First, basic understanding of door mounted verses sail mounted mirrors and shape parameters was obtained by evaluating selected shapes and studying their physical measurements relative to their measured responses. Relationships between the wind noise and drag responses revealed performance range limitations for sail mounted mirrors. Second, a central composite experimental design was utilized to more closely investigate door mounted mirror shape parameters to determine optimal mirror performance potential. The resulting empirical models developed were used to determine the best overall solution."
Development of Door Beam ERW Tubing Made of 1470N/mm2 Cold Rolled High Strength Steel Sheet,"To develop ultra high strength ERW tubing for the door beams of passenger cars using cold rolled steel sheet, an FEM analysis was performed using a tubing deformation model which simulated door beam testing. In the elastic and plastic FEM analysis, the effects of the yield strength and tensile strength of the steel sheet on tubing properties were investigated. The results showed that the tubing peak load in three-point bending increases with an increase in tensile strength. An increase in yield strength enhances the endurance load in the early stages of deflection while it slightly accelerates buckling. The analysis resulted in the production of TS 1470N/mm2 grade cold rolled sheet to be manufactured into ERW tubing. A 0.22%C-0.4%Si-2.4%Mn-0.03%Nb cold rolled steel with a thickness of 2mm was processed in a continuous annealing line which employed water quenching. An ultra high tensile strength along with a relatively high yield ratio was obtained by the introduction of large amounts of tempered martensite into the microstructure. ERW tubing made from cold rolled sheet with a tensile strength of 1470N/mm2 and a yield ratio of 0.82 showed, in actual door beam testing, as high a peak load and absorbed energy as conventional induction heated and quenched ERW tubing made from hot rolled steel. These results show the potential for a more economical manufacturing process."
Clean Digital Data Acquisition With Anti-Aliasing Filters,"When acquiring low-data-rate signals such as temperature, engineers sometimes forget that low-data-rate sampling does not guarantee an uncontaminated recording. Regardless of the sample rate employed in digital data acquisition, signals entering the sampler above half the sampling frequency will be reflected and added into the band below to distort and corrupt the signal of interest."
A New Optimization Approach in the Field of Structural-Acoustics,"It is shown in how far modal correction techniques can contribute to reduce the CPU effort in the scope of numerical structural-acoustic investigations. Due to this technique a quasi-online interactive acoustic optimization of a basic system configuration can be achieved. In this context special focus is pointed on structural optimization aspects. Finally, the limits of validity as to the accuracy of the results obtained by the modal correction approach in the case of larger modifications are determined."
Improving Vehicle Windshield Defrosting and Demisting,"This paper examines the prevailing fluid flow and heat transfer on the windshield of a full–scale vehicle and examines ways of promoting efficient de–icing and demisting. It establishes that present methods of defrosting and demisting windshields are inefficient; since the first area cleared is below the driver's eye level and even this result only occurs some considerable time after the blower has been switched on. The complexity of the windshield topography and the defroster nozzle geometry yield inadequate flow mixing, poor momentum interchange and consequently dead flow zones in critical visibility areas. This study explores ways of improving the defrosting and demisting process through passive means and using the existing air handling system of the vehicle. The results presented are from numerical simulations validated by experiment."
Acoustical Selection of Class 8 Truck Floormats,"Class 8 truck manufacturers use a wide variety of materials for cab floor construction. These include traditional steel and aluminum plate as well as aluminum honey-comb and balsa wood core composites. Each of these materials has unique transmission loss properties. The acoustical performance of the floor system, (cab floor, decoupler, and barrier) depends not only on the acoustical performance of the decoupler and barrier, but also on the cab floor material. This paper outlines an experimental technique for selecting an acoustical floormat system utilizing vehicle and laboratory tests that takes these factors into account."
Squeak and Rattle - State of the Art and Beyond,"Modern trends in noise control engineering have subjected the automobile to the “drained swamp” syndrome. Squeaks and rattles (S&R) have surfaced as major concerns. Customers increasingly perceive S&R as direct indicators of vehicle build quality and durability. The high profile nature of S&R has led manufacturers to formulate numerous specifications for assemblies and components. Even so, a large majority of buzz, squeak and rattle (BSR) issues are identified very late in the production cycle, some often after the vehicle is launched. Traditionally, the “find-and-fix” approach is widely adopted, leading to extensive BSR warranty bills. The “design-right-the-first-time” approach must replace the “find-and-fix” approach. Due to the vast breadth and depth of S&R issues, a comprehensive summary of the present state of the art is essential. This paper includes a literature survey of the current state of the art of S&R, and discusses the methods available to further advance it. Dedicated and focused attempts to advance the state of the art require the formulation of an integrated design strategy that attacks S&R during the earliest stages of design and development, leading to substantial savings in fix and warranty bills."
Enhanced Series of Mid-Size Agricultural Tractors,"The J I Case Company recently introduced a new series of Maxxum tractors (Figure 1). The product line now offers 60, 67, 75, and 84 PTO kW versions. The all new 84 kW version features a new fuel delivery system providing both greater power and reduced exhaust emissions. The powertrain also features increased capacity components required for the reliability of the increased power, 84 kW model. The new series incorporates numerous customer requested improvements of the 5100 Series, including increased comfort, convenience, and visibility features such as swivel seat, in-cab remote coupler flow controls, fender mounted hitch controls and all glass doors."
Upper Extremity Injuries Related to Air Bag Deployments,"From our crash investigations of air bag equipped passenger cars, a subset of upper extremity injuries are presented that are related to air bag deployments. Minor hand, wrist or forearm injuries-contusions, abrasions, and sprains are not uncommonly reported. Infrequently, hand fractures have been sustained and, in isolated cases, fractures of the forearm bones or of the thumb and/or adjacent hand. The close proximity of the forearm or hand to the air bag module door is related to most of the fractures identified. Steering wheel air bag deployments can fling the hand-forearm into the instrument panel, rearview mirror or windshield as indicated by contact scuffs or tissue debris or the star burst (spider web) pattern of windshield breakage in front of the steering wheel."
A Methodology for Evaluating Barriers and Aids to Vehicle Ingress/Egress,"A methodology for evaluating aids and barriers to vehicle Ingress/Egress (I/E) was developed to assess subject performance with prototype features designed to improve I/E. The measures used included Perceived User Difficulty, Total Time to perform a task, and Observed Body Movements identified during video analysis of the I/E tasks. The observed movements included foot/door interference, movement discontinuity, trunk rocking, and upper extremity usage. Pilot testing of this methodology showed that subjective and objective user preference and performance data could be measured and that this information provided a more complete understanding of the problems associated with specific prototype solutions."
Current and Future Trends of Cabin Trining Simulation,"Currently, the airline industry is demanding increased performance from its training staff and training systems. And today, optimal training performance depends on new technology. This challenge has led to the creation of systems that offer a broader range of cabin training solutions. One new system is the IntelliDoor™. This new system is an intelligent door training program that integrates the latest touchscreen computer technology with multi-media interaction and proven instructional methods. The result is a product that delivers consistent, precise, self-paced training without the need for constant instructor supervision."
High Precision in Car Body Manufacturing,"Flexible car body production, including prototyping, is one answer to the market targets where customers ask for an increasing number of models / variants and shorter lead time. The in-house interests of car builders are, besides investment and manpower flexibility, also improved product quality. Quality in body in white is mainly related to geometry (= high precision), to make sure that the final assembly shops will have the right conditions to keep customers satisfied (flush in doors, hood, fenders etc.). The consequences are that both the product and the process equipment have to be in a stable condition to guarantee low spread in the complete car-body. CAD technology is one of the keys to reach this goal, where: Off-line tooling Off-line programming Flow simulation Measurement strategy, off-line / in-line are the main powerful tools to reduce lead time as well as costs. In the realisation phase of the new flexible body shop, in VTK / Gothenburg Sweden, new methods were used for the interaction with all process-suppliers. The co-operation at early stages was highlighted under the aspect of simultaneous engineering. The bottleneck was to find an overall measurement strategy that could be used in all phases of the project, including maintenance during later production. Geometry-wise the targets, for the complete car body, were focused on completely new demands in body-in-white history, with dimensions defined as: ≤ 0.2 mm spread in stamped parts, ≤ 0.5 mm spread in pre assembled parts, ≤ 0.7 mm spread in complete car bodies, for functional values. To reach these values, a metrological concept was developed with a Norwegian company, before the start of the project, and later implemented in our work routines as a standard tool. Process equipment from the main suppliers for the new flexible body shop was controlled geometrically by Volvo-teams with transportable Metronor systems during the three phases: Equipment assembly at suppliers site, Installation on site, Maintenance in production, using the same method of measurement. The result out of this project was that car no. 1 already showed customer quality, even if control-fixtures were not used in the flexible body shop."
"Sound Quality in Cars: New Ideas, New Tools","In recent years, car manufacturers have been shifting their efforts towards improving quality of interior noise, rather than simply reducing noise levels. One of the most important issues, which is today widely accepted, is that noise contains information. Slamming noise should warn us that doors are safely closed, control panel pushbutton “clicks” inform us about the correct turning on of devices, etc.. One of the acoustic researchers' task is therefore to modify the original noise to emphasize quality of information and to reduce annoying components. For these reasons, it is very important to affect noise timbre, by investigating the relationships between mechanical and acoustical parameters. In this paper we describe a workstation (which we have called N.O.T.E.: Noise Optimizator for Thermal Engine) for intake and exhaust system noise synthesis, that integrates an acoustical simulation code with a synthesizer. By means of this flexible system, it is possible to lay out the engine acoustical model, starting from physical laws and using a few general purpose predefined blocks (such as noise sources, resonators, filters, etc.) in a CAD environment. The most important feature of the sound synthesis workstation is the possibility of changing all parameters in real time, making it feasible to “play” every kind of engine noise, before building any prototype."
"Glass Drop Design for Automobile Windows - Design of Glass Contour, Shape, Drop Motion, and Motion Guidance Systems","This paper presents a new computerized approach for designing the automobile window glass contour, the glass drop motion, and the regulator systems. The three-dimensional geometrical relationship of the glass contour, the drop path, and its guidance system have been studied. Methods for barrel and helical drops are presented for optimizing the glass profile and drop path trajectories. Criteria for perfecting the glass contour are developed for shaping the profile of the vehicle clay model. Methods for correcting the glass contour and shape are presented. Examples are provided to illustrate how to improve the design. This approach integrates the development works of glass contour, drop motion and regulator systems. Through this design approach the window glass can fit and move perfectly in the door assembly."
J1850 Compliant Chip Set,"The J1850 Automotive Multiplexing System is opening up new opportunities for automotive designers. Multiplexing not only reduces wiring, weight and cost; but is also adding features by sharing information among modules. For example a door module could communicate that the car is being unlocked and who is unlocking it. The body controller can use this information and tell smart seats and mirrors to adjust themselves to that driver's preferences; tell the radio to turn to a particular station and start the engine. The number of modules that are being multiplexed are increasing in both number and function. Everything from sophisticated engine controllers to simple actuator/sensor nodes are being multiplexed. The challenge with Multiplexing a large number of modules is how to make an integrated circuit that fits all their diverse needs. A complex module, like an engine controller, requires the integrated circuit to be sophisticated enough to handle all the message buffering and filtering functions. Whereas a very cost sensitive, low end module does not require the same performance. How does an IC meet the conflicting needs of an increasing number of modules? Harris Semiconductor found an answer by taking a building block approach. Harris implemented the J1850 analog and digital functions into separate integrated circuits. Doing this not only developed a flexible solution but one optimized to a degree not possible using a single integrated circuit. This article will explain how the three Harris J1850 integrated circuits (HIP7010, HIP7020 and the HIP7030) make up a flexible and cost effective solution for the J1850 Variable Pulse Width Modulation (VPW) Standard."
Designing Mobile Air–conditioning Systems to Provide Occupant Comfort,"The designer of mobile air–conditioning systems must consider the total vehicle in order to provide occupant comfort. An effective refrigerant circuit is only one portion of the vehicle “Comfort System” and without the system's ability to deliver adequate cooling it will not meet the consumer's expectations. A significant considered is the design of the vehicle's body, including the panel outlets and the extent of window glazing surfaces. The location of the panel outlets to provide the occupant's adequate and controllable system airflow for changing weather conditions is a major factor in achieving comfort. Window glazing locations and areas have a major effect on increasing the air–conditioning thermal load by allowing direct solar radiation into the vehicle. Unfortunately, the styling of the vehicle dictates these areas and these constraints very often result in the customer having an air–conditioning system that provides an unsatisfactory level of performance. This paper provides an overview of some areas that are not always given adequate consideration during development of a new vehicle and its air–conditioning system."
Geometries of Simple Hinges Hidden by Flush Contoured Surface Doors,"Doors are very important parts of transportation products as exemplified by the large number of them. In addition to doors for occupants to enter and exit there are doors for access to engine, cargo, luggage, air flow, fuel fill, etc. For transportation products, doors are usually designed to be flush with surrounding surfaces -- and most of them have hidden hinges . There are only a few mechanical alternatives to provide for the opening of doors and the use of simple pivoting hinges is predominant. There are two kinds of simple pivot hidden hinges -- in swinging and outswinging. These are named according to the initial motion of the edge of door with respect to its adjacent surface. Inswinging hinges are most prevalent for occupant entry/exit doors since they are required for most rear doors and they provide more pleasing cut line shapes for current surfaces, usually at lower cost. The door cut lines for hidden hinges which studio designers initially style on proposed products frequently cannot be achieved due to the inherent limitations. While achievable cut lines can be developed using trial -and- error methods, quicker and more reliable results together with a true understanding of the problems requires an analysis which identifies causes and simplifies their visualization. Such an analysis has led to a system for establishing the limits of surfaces and cut lines which has been named the “Volume-in- Space” method. It was developed originally for automotive occupant doors but is also applicable to other transportation items such as doors for luggage, engine, air flow, fuel, etc. as well as other pivoted parts such as convertible tops and aerodynamic suspension arms -- and even non- transportation hinged applications such as cabinets and machinery housings. As the top end view of a hinge center line for automotive occupant doors is observed, there are four basic limits to the volume in which the edge of the door must be contained. These limits are (1) the Swing-By Limit, determined by the requirement of the door swinging clear as it passes by the adjacent panel (or door) at initial movement, (2) the Molding Clearance Limit, determined by the requirement that any randomly located molding on the vehicle surface must not be contacted when the door is fully opened, (3) the Swung Limit, determined by the requirement that the door and the body parts must not contact each other when the door is swung fully opened, and (4)) the Inner Limit, determined by the most inward exterior surface possible with respect to the hinge on the door or other hardware in the door. By examining the parameters which affect each limit, projections can be made regarding ways of increasing the size of the limiting “Volume- in-Space”. Additional discussion is included on advantages for occupant entry/exit which have been gained in some products by orientating the hinge centerline at angles up to 4° from vertical. There are also opportunities for improving the door openings for both body structure and occupant entry/exit."
Advanced Materials and the Pivoting Door Reverser,"HUREL-DUBOIS patented a new concept of thrust reverser in 1981 known as “the door forward reverser”. It gives numerous advantages over the conventional cascade reverser, and in particular is inherently lighter. The extensive use of advanced materials has allowed a highly competitive weight to be achieved. This paper describes the work currently under way for the pivoting door reverser for the ROLLS-ROYCE Trent engine and covers: Thrust Reverser door structure predominantly in composite. Acoustic treatment with composite sandwich. IFS design with carbon bismaleimide material This reverser will be used on MD11 and Airbus A330 aircraft."
Innovations in Design and Functionality of Acoustical Insualtion,"In response to the demands of today's automotive market, advancements have been made where acoustical insulation does much more than just reduce noise. Insulators are now being manufactured to precise tolerances allowing for improved value added features, while also reducing part count and simplifying assembly. In addition, methods have been developed to reduce part weight and provide a product that is fully recyclable while maintaining superior acoustical performance."
Investigation into the Noise Associated with Airbag Deployment: Part II - Injury Risk Study Using a Mathematical Model of the Human Ear,"Airbag deployments are associated with loud noise of short duration, called impulse noise. Research performed in the late 1960's and early 1970's established several criteria for assessment of the risk of impulse noise-induced hearing loss for military weapons and general exposures. These criteria were modified for airbag noise in the early 1970's, but field accident statistics and experimental results with human volunteers exposed to airbags do not seem to agree with the criteria. More recent research on impulse noise from weapons firing, in particular that of Price & Kalb of the US Army Research Laboratory, has led to development of a mathematical model of the ear. This model incorporates transfer functions which alter the incident sound pressure through various parts of the ear. It also calculates a function, called the “hazard”, that is a measure of mechanical fatigue of the hair cells in the inner ear. The repeatability of the model was examined in the present study by comparing its predictive behavior for airbag noise impulses generated by nominally identical airbag systems. Calculations of potential “hazard” made by the model were also examined for reasonableness based on mechanical and biomechanical considerations. A large number of airbag noise pulses were examined using the model. The results provide some counter-intuitive insights into the mechanism of noise-induced hearing loss from deployment of airbag systems. They also indicate that, based upon testing of feline subjects (which are believed to be a good indicator of the risk to the more susceptible segment of the human population), there could be a risk of temporary and possibly permanent threshold shifts in approximately sixty seven percent of the 1990-1995 model year vehicles from 19 manufacturers which were tested and assessed using the human ear model. A statistical estimate of the risk for the human population has yet to be quantified, but work is in progress to do so. Work is also underway to develop a pre-production airbag component test for deployment noise that component suppliers can incorporate into the design and development process. Once injury risk curves and test protocols are established, it is recommended that the ARL Human Ear Model be utilized by the automotive community as the assessment method of choice."
An Innovative Light Weight Instrument Panel Reinforcement Structure,"A light weight, cost effective IP reinforcement structure with a high degree of resistance to steering wheel vibration and with a safe and efficient crash energy management has been developed by Alcoa Automotive Structures (AAS). It also demonstrates other desirable attributes like modularity for world-car platform applications and improved dimensional consistency. The design was analyzed using finite element methods (FEM) for vibration and crash performance and prototype assemblies have been tested. Results demonstrate conformance to vibration and crash response expectations. The concept demonstrates viability and benefits of Alcoa's multiple material and product form solution for IP structures. This paper describes the design and shows some of the analysis and test results"
Anti-Trap Function for Electrical Power Windows,Today electrically driven windows are a standard feature in many automobiles. Further technical enhancements like express up/down or remote controlled central closing are important features for increased comfort and ease of operation. Some of these new functions cannot be implemented without inherent safety precautions to avoid the risk of being trapped and severely injured by automatically moving window panes. A sophisticated technical approach is described which solves this problem using state of the art electronics and modern software design combined to yield high cost efficiency. This patented concept is based on motor current detection. Theoretical explanations and practical results illustrate that it is superior to other approaches. Examples are shown of high volume applications currently in production.
Practical Noise and Vibration Optimization of HVAC Systems,"Next to air temperature, humidity, and air quality, it is sound emission that exerts a significant impact on the driver's and passenger's comfort. Major progress in vehicle acoustics has motivated vehicle manufacturers and systems suppliers to evaluate HVAC systems no longer by their air conditioning performance alone. Sound emissions and sound quality have become additional important criteria for the development of new HVAC systems. In the initial conception phase, where systems and packaging considerations are made, acoustic optimization must begin with preliminary system studies and feasibility studies. In this phase acoustics should be based on fairly general systems specifications which describe the desired degree of acoustic comfort. In the subsequent design phase follows the specification of the acoustic goals and the optimization of the HVAC unit. Detailed analysis and optimization of air flow and blower are the common targets for improvement at this time. Finally, component optimization starts with including the detailed design process and the mounting of possible noisy components. The paper further outlines four pillars, on which good acoustics of an HVAC system is based, focusing on the subsystem ‘air flow’. These are reduction of pressure drop, flow optimization, sound proofing and sound deadening, and at least the insulation of structure borne sound."
Psychoacoustic Considerations in Vehicle Ergonomic Design,"In order to experience harmony among the various perceptual cues experienced by an automobile customer, the acoustic environment must be considered. Acoustic events generated by automotive systems can have a dramatic effect on a customer's impression of vehicle quality and reliability. Additionally, certain vehicle segments are partially defined by the vehicle's sound characteristic. For example, luxury segments are defined by quiet and smooth powertrain sound, whereas some sports car segments are defined by loud and rough powertrain sound. This paper is a discussion of the impact automotive acoustic events can have on the customer. Addressed will be the methods typically used in both data collection and subsequent jury evaluations. Two case studies will be discussed. Finally, there will be a brief discussion on the future role of psychoacoustics in the vehicle environment. Exploring the relationships between acoustic, visual and haptic stimuli is an area which has been largely unexplored. Additionally, auditory warnings and displays may become increasingly important in advanced safety and navigational systems and can be positively influenced by psychoacoustic principles and methods."
"International Space Station Temperature and Humidity Control Subassembly Hardware, Control and Performance Description","The temperature and humidity of the air within the habitable areas of the International Space Station are controlled by a set of hardware and software collectively referred to as the Temperature and Humidity Control (THC) subassembly. This subassembly 1) controls the temperature of the cabin air based on a crew selected temperature, 2) maintains humidity within defined limits, and 3) generates a ventilation air flow which circulates through the cabin. This paper provides descriptions of the components of the THC subassembly, their performance ranges, and the control approach of the hardware. In addition, the solutions of the design challenges of maintaining a maximum case radiated noise level of NC 45, controlling the cabin air temperature to within ±2°F of a setpoint temperature, and providing a means of controlling microbial growth on the heat exchanger surfaces are described."
Laminated Sidelights and Asymmetrical Windshields for Cars,"This paper deals with new concepts for automotive glazing applications, with reference to weight reduction, improved security, and enhanced robustness: Laminated sidelights and asymmetrical windshields are considered. Main advantages are reviewed. Best designs are proposed considering the main functionalities of both products, particularly the mechanical properties required for automotive glazing."
Evaluating the Intrusion Resistance of Installed Motor Vehicle Glazing,Intrusion resistant glazing increases the time and effort required to gain unauthorized entry to a motor vehicle. This paper presents the results from a series of tests designed to measure the performance of laminated intrusion resistant glazings as installed. These tests were conducted as part of a study to evaluate the performance of different polyvinyl butyral (PVB) interlayer thicknesses and adhesions for penetration resistance. Readers of this paper should gain a broad understanding of the performance of these glazings and their level of resistance.
Interior Noise Analysis Based on Acoustic Excitation Tests at Low-Frequency Range,"An experimental analysis is performed on structure-borne sound in the low-frequency range under 50 Hz by applying an acoustic excitation test to a fully trimmed vehicle. This analysis makes use of the structural-acoustic reciprocity technique in which the vibration distribution of the car body is measured while the vehicle is being acoustically excited by a loudspeaker placed at the position of a passenger's ear. This paper explains why the concept of reciprocity should be applied to the study of low-frequency structure-borne sound, and discusses the causes of road noise, a typical problem in structure-borne sound associated with passenger cars."
Experimental Evaluation of Wind Noise Sources: A Case Study,"Several of the authors have recently developed procedures to efficiently evaluate experimentally the relative contributions of various wind noise paths and sources. These procedures are described and, as a case study, results are provided for the noise in the interior of a production automobile subjected to wind tunnel airflow. The present measurements and analysis indicate that for the tested vehicle significant contributions to interior noise are provided by underbody and wheel well flows, radiation from the roof and seal aspiration. A significant tone associated with vortex shedding from the radio antenna was also noted."
Empirical Noise Model for Power Train Noise in a Passenger Vehicle,"Power train noise reaches the interior through structureborne paths and through airborne transmission of engine casing noise. To determine transfer functions from vibration to interior noise a shaker was attached at the engine attachment points, with the engine removed. A simple engine noise simulator, with loudspeaker cones on its faces, was placed in the engine compartment to measure airborne transfer functions to interior noise. Empirical noise estimates, based on the incoherent sum of contributions for individual source terms times the appropriate transfer function, compared remarkably well with measured levels obtained from dynomometer tests. Airborne transmission dominates above 1.5kHz. At lower frequencies engine casing radiation and vibration contributions are comparable."
Analysis of Vehicle Pillar Cavity Foam Block Effect on Interior Noise Using SEA,"Closed cell foam has been used for filling vehicle pillar cavities at select locations to block road noise transmitted through pillars. In the past, most pillar foam implementations in vehicle programs were driven by subjective improvements in interior sound. In this study road test results are used to correlate a detailed CAE (Computer-Aided Engineering) model based on the statistical energy analysis method. Noise reduction characteristics of pillar with a number of foam block fillings were then studied using the CAE model. The CAE models provided means to model and understand the mechanism of noise energy flow through pillar cavities. A number of insightful conclusions were obtained as result of the study."
Perceptual Transfer Function for Automotive Sound Systems,Measurement of acoustic frequency response is extended to include aspects of speech and music perception in rooms. An apparatus is described that combines established and new techniques in a computer based measuring system. The resulting objective plot has a better correlation with subjective assessment than previous methods. The flexibility of the measurement platform encourages future development.
All Olefinic Interiors-What Will It Take To Happen?,"TPO is getting wider acceptance for automotive applications. An exterior application like a fascia is a very good example. Interiors are still a challenge due to many reasons including overall system cost. For interior applications, “all-olefin” means it mainly consists of three materials: TPO skin, cross-linked olefinic-based foam and PP substrate. The driving force for TPO in Europe is mainly recyclability while in the USA, it is long-term durability. This paper describes the key limitations of the current TPO systems which are: poor grain retention of TPO skin, shrinkage in-consistency of the skin, high cost of priming (or other treatments) and painting of the skin, lower process window of the semi-crystalline TPO material during thermoforming or In-mold lamination / Low pressure molding, high cost of the foam, low tear strength of the foam for deep draw ratio etc. The paper shows the different ways of manufacturing the all olefinic parts which are: thermoforming over PP substrate, different Low pressure molding with in-mold lamination techniques, expanded PP foam process, slush molding etc. The limitations for each process and suggestions to overcome the disadvantages will be discussed to make all olefinic TPO interior parts viable and cost effective. The possibility of reducing the overall system cost will also be discussed such as: general information on formulation development to reduce the skin thickness for thermoforming, how to improve the properties of foam to reduce the thickness without affecting the formability and resiliency, value added recyclability of the skin/foam offal from production, and improving the paint efficiency etc."
Frequency Domain Considerations in Vehicle Design for Optimal Structural Feel,"A vehicle perceived to be solid and vibration free is said to have good “structural feel”. Specification for vehicle design to achieve a good stuctural feel depends heavily on the management of resonant modes existing in the low frequency domain. These resonances include vehicle rigid body, chassis subsystem, body flexure and large component modes. A process to specify the placement of resonant modes in the low frequency domain is discussed. This process allocates blocks within the frequency domain for classes of resonant modes stated above. Segregation of these blocks of resonant modes in the frequency domain limits modal interaction, thereby minimizing sympathetic vibration. Additionally, known areas of human body sensitivity within this low frequency domain are stated. Lastly, known vibration inputs are identified. This process is cognizant of these inputs and avoids overlapping with the vehicle resonant modes to provide further insurance of minimal modal interaction."
The Strategy of Accelerated Reliability Testing Development for Car Components,"This paper analyzes the reasons why current accelerated reliability testing (ART) results for passenger cars often cannot give accurate information for sufficient reliability, fatigue, and durability evaluation and prediction in the field. Why does accelerated testing (AT) give often minimum benefits for companies that use it? The basic principles of strategy that can help to eliminate these reasons will be described. In order to execute this strategy the following will be shown: the full hierarchy of the car and its components in a connection and interaction with each other; how accelerated environmental testing can be improved if a simultaneous combination of basic environmental factors (temperature, humidity, pollution, radiation, etc.) will be used; how each of these factors can be simulated more accurately in the laboratory; how one can improve accelerated corrosion testing of the car components if one takes into account that it is a combination of chemical, mechanical, motion, etc. influences; how one can improve vibration testing if one takes into account that the car's vibration is complicated and acts simultaneously with the rotation of the wheels; etc."
The Effects of Outlet Geometry on Automotive Demister Performance,"The established method of clearing a misted car windshield or of maintaining a clear view under misting conditions is through the application of an air supply via jet outlets in the instrument panel. The ability of such arrangements to perform adequately is a function of the prevailing environmental conditions, the vehicle speed, the condition of the demist air source and the geometry and arrangement of the jet outlets. This paper presents experimental data obtained in a purpose built environmental chamber designed to accommodate simple rectangular jets impinging on a misted glass surface. The facility consists of three conditioned air sources applied to a test chamber designed to represent the external, internal and demist air flows. Mist conditions on the glass surface are determined using a novel technique employing a CCD camera acquiring grey scale images which are digitally analysed to generate mist detection, grading and clearing contour data. The test facility and mist analysis techniques are described. Transient jet performance is investigated in a parametric study that addresses the effects of jet aspect ratio, offset, impingement angle and mean volume flow rate on clearing performance. Results are presented in terms of parameters derived from the images recorded during the clearing process. These parameters include rate of clearing terms, breakthrough time and location of clearing centre relative to geometric impingement point. Steady state performance is presented for a number of representative geometries by examining the size of the clear area for a range of interior humidity levels."
The Importance of Sealing Pass-Through Locations Via the Front of Dash Barrier Assembly,"An improvement in a vehicle's front of dash barrier assembly's acoustical performance has in the past been addressed by both adding individual absorbers and increasing the overall weight of the dash sound barrier assembly. Depending upon the target market of the vehicle, adding mass may not be an option for improved acoustical performance. Understanding the value of an increase in vehicle mass and / or cost for a specific level of improved acoustical performance continues to plague both Original Equipment Manufacturer (OEM) Engineers and Purchasing representatives. This paper examines the importance of properly sealing the front of dash pass-through areas and offers recommendations which can improve the overall vehicle acoustical performance without the addition of cost and mass to the vehicle. It also examines how the acoustical performance of an engineering change can be determined and relates this performance to a Value Statement in an effort to assist the engineering community in judging the overall value of this engineering change."
The Next Step in Acoustical Part Weight Reduction,"Weight reduction with maintained part performance is a continuing trend throughout the automotive industry. Acoustical insulation parts (carpet underlay and dash insulators) are no exception. Several years ago, ICI Polyurethanes led the industry in establishing a molded density standard of 48 kg/m3. Although this is the current production standard, the technology drive is toward even lower weights. Recent technological demonstrations show that molded densities of 35-38 kg/m3 are achievable. In addition to removing weight, acoustical performance can be maintained with no deficiencies in physical characteristics."
Acoustical Advantages of a New Polypropylene Absorbing Material,"Sound absorption is one way to control noise in automotive passenger compartments. Fibrous or porous materials absorb sound in a cavity by dissipating energy associated with a propagating sound wave. The objective of this study was to evaluate the acoustic performance of a cotton fiber absorbing material in comparison to a new polypropylene fibrous material, called ECOSORB ®. The acoustical evaluation was done using measurements of material properties along with sound pressure level from road testing of a fully-assembled vehicle. The new polypropylene fibrous material showed significant advantages over the cotton fiber materials in material properties testing and also in-vehicle measurements. In addition to the performance benefits, the polypropylene absorber provided weight savings over the cotton fiber material."
Assessing the Performance of Electrically Heated Windshield,"The safety and comfort aspects of passenger vehicles are significant sales argument and have become a topic of rising importance during the development process of a new vehicle. The objective of this study is to compare the performance of several current model vehicles, highlight the drawbacks of current defrosting/demisting systems and point the way to improved passive mechanisms. The investigation is experimental. The work presented is an experimental and numeric investigation of the clear-up pattern of a current vehicle fitted with an electrically heated windshield. Nottingham FDL climatic wind tunnel is used to perform the experimental tests. The clear up pattern developed utilising the vehicle defroster system is digitally captured and compared to the clear up pattern developed utilising the electrical heated windshield. Moreover, the clear up pattern developed using the vehicle defroster system is used to validate a computational model. The aim is to build a confidence on the relatively new developed numerical tools for phase change simulation. The design features of electrically heated windshields and the associated gadgets are briefly discussed. With the predicted shift to use 42V powernet, the market will require more vehicles to be installed with electrically heated windshields. The main benefit to the vehicle customer is the convenience of reducing the clear up times."
Safety Performance of a Chemically Strengthened Windshield,"Safety performance of an experimental windshield with a thin, chemically tempered inner pane is compared with the standard windshield and other experimental windshields. The chemically tempered windshield has a penetration velocity of 35 mph compared with 26 mph penetration velocity for the standard windshield and has lower peak head accelerations than other types used in the experiments. The windshield tested produces a bulge on impact, which decelerates the head over a long distance with low accelerations. The bulge or pocket is lined with particles that are less lacerative than the standard annealed glass."
A Vibro-Acoustic Test System for Simulation of Saturn V Dynamic Launch Environment on Major Space Vehicle Structures,A description of the largest Acoustic and Vibration Test Facilities in existence for the simulation of major launch vehicle dynamic environment is given and the operational characteristics of both are discussed. Sinusoidal and random excitation techniques are described and unique vibration control methods presented. A comparison of the effects of vibration and acoustic excitation on major space vehicle structures is made.
Causes of Significant Injuries in Nonfatal Traffic Accidents,"The Vehicular Trauma Research Group of the UCLA School of Medicine is currently conducting intensive studies of selected traffic accidents. Data is presented from an analysis of the first 150 traffic accidents studied. The role of vehicular design, mechanical failure and the performance of the new 1966 windshield in injury causation are discussed and illustrative examples are presented. The importance of detailed studies of traffic accidents is stressed as a method of yielding information not readily available by other methods of study. This approach is mandatory to evaluate new and pending vehicular design modifications and may be the only method of detecting and assessing the role of mechanical failure in traffic accident causation."
Ejection - The Leading Cause of Death in Automobile Accidents *,"From on-scene investigations of 139 fatal automobile accidents during four years, it was found that of 177 persons killed, 48, or 27%, died by ejection, which is thus the leading cause of death. As would be expected, most (two-thirds) were ejected through opened doors; others were ejected through windshields, open convertible roofs, or door windows. From the investigations it is postulated that 80% of the ejection deaths would have been prevented had the ejectees worn seat belts."
Passenger Protection from Front-End Impacts,"Scientific methodology and engineering techniques were applied to a series of thirteen automobile collision experiments involving the front-end impact exposures of full-size passenger vehicles rear ending identical sedans. The purpose was to evaluate the relative protective merits of seat designs, steering columns, windshields, restraints and general interior surface design with respect to the many variables common to front-end impacts. The front-end collisions reported in this paper provide additional design data for protection of motorists from collision-injuries for the wide range of exposure speeds from 10 through 55 mph."
Automotive Piston-Engine Noise And Its Reduction - A Literature Survey,"This paper reviews the sources of externally radiated automotive piston engine and vehicle noise and describes them in detail. The effects of various design and operational characters on intensity and character of noise, noise measurement, and analysis and identifications procedures are given extensive examination. A summary of current research on the reduction of engine noise is presented."
Basic Facts about Noise as Related to Aviation,"NOISE has two aspects: (1) subjectively, it is any unwanted sound; (2) objectively, it is characterized by many variables. The subjective view is important in determining the response of people to aircraft noise and in establishing engineering design objectives for noise control. The engineering of noise control deals with the objective aspect in three parts: 1. The noise source — characterized by its total noise power output and the distribution of this power with respect to frequency and space. 2. The path — propagation in structures, through the air, and over terrain as influenced by properties of materials, geometry, meteorological conditions, and topography. 3. The received noise — its sound level, frequency spectrum, time pattern, and other variables as required to correlate with the subjective response of man in the aircraft, on the line or in the community."
Safety Glass Breakage by Motorists During Collisions,"Five intersection-type collision experiments were conducted at 40 mph to provide data on several categories of collision performance. This paper presents the interactions of passenger heads with car windshields and side-glass. Instrumentation included 60 channels of force and acceleration data, supported by the photographic coverage of 40 cameras. Tri-axial accelerometers, mounted in anthropometric dummy heads and chests, and strain gauges bonded to windshields facilitated data collection on the relative collision performances of different types of safety glass."
Accidental Motorist Ejection and Door Latching Systems,"A general dissertation on the factors relating to accidental door opening, including: nomenclature, classification of the various types of loading of significance; description of five known causes of accidental door opening not associated with door latch strength; supporting evidence from full-scale collision research; photographic display of 1964 model door latches; review of the factors relating to the evaluation of door latch installation and three suggested test configurations to cover the most significant causes of accidental door opening."
A Review of ACIR Findings,"During a period of ten years, ACIR has amassed a large accident sample, drawn from a total of 28 states. Statistical analysis has aimed at (1) identification of leading injury sources and (2) statistical evaluation of car safety features. Studies show that ejection, the steering wheel, instrument panel, and the windshield are the four categories most often associated with car occupant injuries. Countermeasures include seat belts, safety door latches, recessed-hub steering wheels, and instrument panel padding. Studies have shown partial-to-substantial countermeasure effectiveness for seat belts, safety door latches, and instrument panel padding. Analysis of other safety devices is under way."
Modern Concepts in Rapid Transit and the Use of Rubber Tires for Transit Vehicles,"A resurgence of interest in rapid transit has resulted in a multiplicity of systems being proposed. Among these have been proposals to use guided rubber tired vehicles. The history and current status of development of a number of these systems is presented. The development of a new supported, dual track rubber tired system is described together with a review of operation and design considerations. Rolling resistance and acoustical factors are discussed and costs of several types of systems are compared. While rubber-tired systems are more costly than those having conventional steel wheels, special consideration of grades and community acceptance may justify their use."
Tooling for Multiple Lead Applications of Electrical Discharge Machining,"Multiple lead enables electrical discharge machining to compete as a production method with conventional machining methods, provided proper tooling is used. In this paper, the electrical discharge power supply, the machine, the work and electrode holding fixtures, the electrodes, and the dielectric are all considered as tools. Each has its individual function in obtaining an efficient EDM cut which is essential for multiple-lead operation. The power supply must be capable of producing discharges that are compatible with the electrodes and workpieces being used. Machines must furnish the servo function and auxiliary cycling equipment. Work and electrode holding fixtures must hold precision relationship between electrodes and workpieces as well as eliminate electrode vibration and direct dielectric flow. The electrodes must be suitable to the application, and because they are expendable, must be economically produced. The dielectric must be suitable to the application and must be adequately filtered and directed."
General Approach to the FLUTTER PROBLEM,"AGENERAL approach to the flutter problem is outlined, which can be used to investigate any mode of flutter of any structure provided the air-forces are known. The method can be used to investigate the possibility of flutter on such structures as airplane wings, tail surfaces, and bomb doors, aircraft propeller blades, vehicular bridges, buildings, and so on. With a well-known solution for the air-forces for two-dimensional flow over an airfoil with an aileron, equations have been derived which can be used to determine the flutter speed for the wing or tail surfaces of any conventional airplane. The use of still-air vibration tests in obtaining the structural friction of structures, and in checking a part of the flutter computations experimentally is indicated. Finally, to suggest the possibilities in the use of this method, a standardized procedure for its general application to aircraft flutter problems is outlined briefly."
"Heating, Ventilating, and Cooling of Passenger Cars","MANY question whether a complete job of air-conditioning passenger cars for all weather conditions can be done at a price which most car buyers care to pay and with assurance that dependable and acceptable results can be guaranteed, Mr. Chase reports in prefacing this paper, a comparative study of existing heating, ventilating, and cooling systems. Some 1939 and many more 1940 car models, he believes, yield greatly improved results in heating the entire car and ventilating it well with all windows closed, but, he points out, the design of such systems is still in a state of flux. Mr. Chase divides all currently available systems into four classifications for convenient discussion: (1) heating by recirculation only, ventilation incidental; (2) heating in which part of the air is recirculated and part taken from outside and can be heated before delivery; (3) heating in which all air passing through heater is taken from outside; (4) systems which include means for heating, cooling by refrigeration, and at least incidental circulation. The author describes and compares current systems in each of the classifications and comments on the problems, advantages and disadvantages involved in each of the designs. He includes also structural considerations, mentioning that, except for compressors, valves, and a few other somewhat special parts, most of the components of all these systems are produced largely from sheet metal or are die-cast in zinc alloy."
DEFICIENCIES of CONVERTED PASSENGER AIRPLANES for CARGO TRANSPORT and OPERATING REQUIREMENTS,"SHORTCOMINGS of the converted passenger plane are at least 10 in number, says Mr. Froesch, classifying them as follows: (1) floor slope and irregularity of floor at door causing concentration of load at that point; (2) floors too weak, requiring reinforcing; (3) doors too narrow for entrance of bulky loads; (4) no anchorage for load fasteners; (5) no provisions for cargo handler station; (6) hard to distribute load so as to give a satisfactory center-of-gravity location; (7) lavatory in the wrong place; (8) insufficient fire extinguisher protection; (9) door sill heights too variable; (10) circular or oval fuselage shape, which cannot be used effectively. A big problem is to get the rate down to the point where repeat business will follow. Eventually this might mean a 10 to 12¢ per mile rate under proper designing, Mr. Froesch declares. But, he says, size and capacity of the cargo plane cannot be predicted until a thorough analysis of the air express and freight market has been made. A density-volume ratio of 8 to 9 lb per cu ft can be used, Mr. Froesch says, as a design criterion in figuring size of compartment. He points out heating and ventilation aspects of the cargo compartment and explains desirability of having a small compartment for protection of valuables close to the cockpit. The airplane should also be designed so that preventive maintenance and service methods can be best applied."
Passenger-Car Road Noise,"THE authors introduce their paper by outlining the various sources of noise existing in the motor car, together with some of the suppression means. Noise measurement, test methods, and the mechanism of the transmission of forces generated by the contact between the tire and the road to the body and frame are discussed. The authors state that, since these forces produce motion and deflection of the body, they are responsible for the road noise, and conclude that the proper approach to a method for suppressing road noise is through the structural design of the vehicle. They suggest, in the main, the localizing of stress to stress members, the raising of the resonant frequencies of the structure, the detuning of the suspension system, the body, and the frame, together with some isolation at selected points."
What Motor Cars Can Be,"FUTURE motor-car development, Mr. Stout contends, will follow the functional art of bus and airplane development rather than motor-car precedents. The interior instead of the exterior, he believes, is the basic thing to be studied, pointing out that passenger room has been growing less and less. The car of the future, therefore, he predicts, will have an interior that extends out the full width of the car with no running boards, will have totally enclosed wheels, will have a unit frame and body, the engine in the rear, and either double or sliding doors. The effect of rear-engine construction on ride, bounce control, braking, and traction on muddy and icy roads is explained. New body materials, such as plastics, are looked for on future cars to insulate them from the radiant heat of the sun, especially for roofs. Mr. Stout sees light-weight air-cooled engines in future cars, weighing not over 3½ lb per hp. The possibilities of rubber springs are discussed."
WOOD FOR AUTOMOBILE BODIES 1,"Shortage of the most desirable kinds of wood for automobile-body purposes has necessitated the substitution of second-choice woods having the essential required properties and the buying of stock for body parts in cut-up dimensions that conform in size with those now produced in the cutting-room. An investigation by the United States Forest Products Laboratory as to the species, kinds, grades, sizes and amounts used by the automotive industry shows that maple and elm comprise over one-half the total amount used and that ash and gum constitute one-half of the remainder. Although the quantity of ash used has not decreased, the increase in the production of medium and low-priced cars in the last few years bas caused a proportional increase in the demand for maple and elm. Classifying cars for purposes of analysis into four groups, small, medium, medium-large and large, the investigators found that the woods most used in small cars are hard and soft maple, elm, birch, beech, oak, gum and pine; that maple, elm and birch are used extensively in bodies of the medium and medium-large classes; and that ash predominates in the large cars, with hard maple as an alternative choice. Fifty-one per cent of the running-boards are made of pine, and 17 per cent are made of sound wormy oak. Oak, ash and elm are used for top-bows in the proportion of 92, 7 and 1. The grade of lumber used in bodies is very high, 40 per cent being firsts and seconds, and 49 per cent No. 1 common and selects. The problem of eliminating light or brash ash is important and, while there are no visual means by which tough and brash ash can be separated, the factors that afford a fairly reliable criterion of strength and toughness are density, rate of growth, proportion of summerwood and the original position of the wood in the tree. Seasoned ash that has good weight and is sound will have strength. Unseasoned ash, on the other hand, cannot be judged by weight. Little or no uniformity in size of corresponding parts was found among the various makes of body, although the majority fall within very narrow limits. Charts have been prepared showing the range and grouping of the sizes of several of the main body parts, such as the body and door pillars of closed bodies, the main side sills, the side roof-rails, the front and rear roof-rails and the rear belt-rails. The stock used in the larger bodies is of very high quality; in open bodies a few small defects are allowed; in smaller and lighter bodies the requirements are not so severe, a mixture of woods is used, and some defects, such as small sound knots, are allowed; in soft maple, elm and gum, considerable amounts of stain and dote are admitted. When the requirements are not exacting it would be possible to utilize sound low-grades; the use of clear stock where sound stock is sufficient introduces unwarranted expense and wastes material that might serve higher purposes. As the waste in cutting ranges from 20 to 50 per cent, it is evident that careful work at the saws may result in considerable saving. Other ways in which saving may be effected are the gluing-up of stock to get required sizes and a more general use of ready-cut small-dimension stock. As automobile builders are much interested in finding woods that may be substituted for those now in use, a table is given showing the specific gravity, strength, stiffness, shock-resisting ability and hardness of the principal species as compared with those of forest-grown white ash; and the advantages and disadvantages of first and second-growth timber, and such woods as ash, hard and soft maple, rock and white elm, birch, red and sap gum, oak and the softwoods are discussed."
GLIMPSES OF BALLOON-TIRE PROGRESS,"The balloon tire has run the gauntlet of skepticism and credulity and has received scientific and popular approval from engineers and car-owners. The reasons for its acceptance are satisfactory appearance, practicability and transportation comfort. Tire and rim sizes, masquerading for years under wrong dimensional markings, have caused immeasurable inconvenience. This condition resulted from poor standards or entire lack of standards supervision. A committee with backbone is needed to fix and to maintain standards. Rapid balloon-tire tread-wear depends on tread profile, pressure and movement. Increased inflation-pressure and a scientifically designed tread will reduce the rapidity of this wear. Tread-contact areas and pressures are pictured to explain the advantages of a properly designed tread, and to demonstrate that the casing carries an appreciable part of the tire load. Tread configuration should assure traction, flexibility, easy steering, and good wear and should be not too rugged. Tread surface should be largely non-skid for best all-year and all-highway service. The public is confused by diverse balloon-tire inflation-pressure tables offered by tire and vehicle makers. One standard table can and should be adopted for all balloon tires. Increasing the number of plies in a balloon tire increases the ease of entry of a puncturing object into the tread, but decreases the probability of complete penetration and actual deflation from puncture. Gradual loss of air from tires is due chiefly to diffusion through the tube rubber. The rate depends on daily mileage, road conditions and tube quality and thickness. Average diffusion amounts to from 1 to 5 lb. per week. Volume of noise in closed cars is no greater with balloon tires than with high-pressure tires, as indicated by audiometer measurements. Different cars show important differences in noise volume, due principally to differences in engines. Balloon tires are not a fundamental cause of shimmying. Improper balance between front-end units appears to offer the chief cause. There is no common remedy. More original and thorough research by experts in their particular fields is urged so that America will lead in the refinement as well as in the production of tires and automobiles."
PYROXYLIN ENAMEL OVERCOMES FINISH FAILURES,"Public demand for more durability in automobile finishes has led to new developments in finishing materials and methods through cooperation of finishing materials manufacturers and automobile builders. By experimentation it has been found that certain cellulose nitrate materials, when applied over suitable under-coats, dry quickly in the air by evaporation of the solvents and leave a film that is hard and tough. Its durability is many times greater than that of the most durable finishing-varnish and, as it has been discovered that sufficient luster can be produced by rubbing and polishing the unprotected cellulose-nitrate surface, one of the large automobile production plants adopted, in July, 1923, as its standard method of finishing, the use of such a finishing coat over primer and surfacer coats, obtaining the luster by polishing the cellulose-nitrate top-coat. A number of companies have now adopted this process. Certain finishing-material companies, having discovered how to increase the quantity of cellulose-nitrate in solution without increasing the viscosity, made possible its use for automobile finishing. The change from a varnish to a pyroxylin finishing-system seems simple but a cellulose-nitrate finishing-material is complex. A large number of gums and oils can be used to obtain the desired properties but considerable study is required to determine the kinds and the quantities to use. The softeners and the stabilizers may be part of the solvents but they have their own duties to perform. The solvents hold the cellulose nitrate in solution and their evaporation permits the film to be deposited and harden. The nature of the solvents greatly influences the character of the film. Not all pyroxylin materials have great durability. This is obtained only by using the proper basic materials, combined in the right proportion and applied in the correct way. The fundamental cause of the failure of finishes is the contraction of the top material while the underlying material is still moist. During exposure to rain or other dampness out of doors, the entire film absorbs moisture, swells and softens. When the sun comes out, the outer surface dries and contracts and, if the material is not sufficiently elastic to withstand the stresses, cracks develop. Durability can be increased by reducing the severity of these factors. By nature, the pyroxylin film is much less absorbent than the varnish film and the particles of pigment shade the materials beneath so that only the extreme outer surface is exposed to the sunlight. In time, the moisture and sunlight do, however, cause a type of failure known as “chalking.” This effect is of such microscopic depth that it can be removed easily by washing with a mild abrasive or by polishing, thereby exposing a fresh surface, and in the case of a good cellulose-nitrate finish the washing or polishing can be repeated many times before any serious wearing away of the surface occurs. By mild polishing every few weeks, together with ordinary cleaning of the car, the finish can be kept with an appearance as good as it had on the showroom floor. The author describes the fundamental operations in finishing an automobile body with paints and varnishes, explaining the purposes of the different coatings and the filling and rubbing, and classifies the successive coatings in all finishing systems as (a) primer, (b) surfacer, (c) color and rubbing, and (d) finishing. To determine the cause of the rapid failure of finishes, test panels were exposed to the weather during different periods of the year and it was found that the length of life of varnishes depends greatly upon the season, varying with the amount of sunlight and heat, being shortest in summer and longest in winter. These tests also showed that the primer and surfacer coats were very durable but that the color and rubbing varnishes were of low durability, failing in from 1 to 5 weeks when unprotected by finishing varnish. The real reason for the short life of the ordinary automobile-finish was discovered to be the failure of the color and rubbing varnishes, which crack and take the finishing varnish with them. However, the finishing varnish is itself partially responsible for the failure of the color and the rubbing coats, because its film is easily scratched by grit and cleaning or by other mechanical injury, and failure of the underlying coat starts at these unprotected spots. The life of a varnish surface is shortened by regular polishing even if it is washed regularly only with water. A polish that is as nearly harmless as any is made of linseed oil mixed with enough turpentine to prevent the application of too heavy a film of oil. The life of ordinary production varnish-finishes can be doubled or quadrupled by the use of color and rubbing varnishes of high durability but they require a long time for air-drying and forced drying is likely to injure the color."
HEADLIGHTS,"Two points are cited as illustrating the difficulty of enforcing the present regulations, namely, (a) the variation in the angle of the headlight beam caused by the compression of the springs when the loading of the car is changed from no load to full load and (b) the variation of the tilting of the beam caused by the pitching of the car on an ordinary road, the effect being similar to that produced by flashes of lightning in a pitch-dark night. Denial is made of the author's alleged advocacy of diffused lighting and comparison is made of the distribution-curves obtained with frosted bulbs and those obtained with fairly good lamps conforming to the Society's specifications. Attention is called to three points in this comparison: (a) the light from the frosted bulb along the horizontal is only about 50 per cent of that available with a lamp conforming to the Society's specification, (b) the foot-candle illumination measured perpendicularly to the beam at various points on the surface of a level road is much less with the frosted bulb than with the lamp of the Society's specification, how much harm a bright illumination immediately in front of the car interferes with acuity of vision is a subject for additional research and (c) the light from the frosted bulb does not change appreciably for any angle through which the chassis is likely to move as a result of road shocks; consequently, when the frosted bulb is used, road shocks and spring vibration do not affect the eyes of an approaching driver. Sharp cut-off above the horizontal is considered in-advisable. The possibilities of non-symmetrical lighting, the author believes, are worth considering, and the results of some experiments are detailed. He expresses a preference for the use of two diffused lights as regular equipment and of a third lamp, adjusted according to the Society's specifications, so that the maximum candlepower would be horizontal. Reference is made to the test target in use by the Royal Automobile Club and to the results of tests made with it, but this method is said to be objectionable as a basis of specifications because it is tedious and the results depend largely upon the condition of the observer's eyes. Although measurements of all the imaginable functions of the human eye have apparently been made, such tests should be repeated under automobile-lighting conditions, for factors that previously may have been neglected in tests frequently become important when the conditions are changed. As the normal eye requires nearly 1 sec. to adjust itself to radically changed conditions of illumination, this period is dangerously long when a car is running at high speed."
"Automobile Bodies, from the Abstract Customer's Viewpoint","CONSTRUCTIVE criticism of automobile bodies as now built is given herein, based on experience gained in driving five-passenger sedan cars of many makes a total distance of nearly 10,000,000 miles in one year in tests at the General Motors Proving Ground. The fault finding, although humorously exaggerated, will be valuable if taken seriously, as it gives to all body designers and builders the benefit of testing experience that few companies are in a position to gain at first hand. The author treats his subject from the viewpoint of the abstract customer; that is, the automobile-purchasing public as a whole and as represened by the imaginary average man, who is assumed to have average stature and body structure and to drive all the different makes of car. Thus he is assumed to change from one to another make frequently, instead of becoming used to only one or two cars. Factors that influence the initial and the repeated purchase of a car are given in the order of their importance, and the index by which the customer measures the merit of the car is said to be the maximum satisfaction he has experienced with each individual characteristic in all the other cars he has driven. In other words, the best in all cars is his basis of comparison of the individual car and body, and he can be completely satisfied only if one car is as good in every respect as the best that has been found in any car for that particular feature. Standardization of fundamental dimensions based on the measurements of the average figure of all drivers is indicated as a need of primary importance. Strictures are laid on various bodies because of interference with vision in front and through the rear window, because of squeaks and rattles and many other details that, because they are constantly evident to eye or ear, are more annoying than faults of the chassis. No attempt is made, however, to set up specifications for a body that will give complete satisfaction to various classes of user."
DAMPING IN SUSPENSIONS,"THE various types of damping present in vehicle suspensions and their effect on the ride are discussed by Mr. O'Connor, who compares the characteristics of the various types of damping with the mathematically adaptable viscous damping. The ideal damper and the present-day practical approach are considered. The discussion is maintained on a nonmathematical plane throughout, as the author believes that the mathematics of vibration theory is ably covered in numerous texts on the subject."
Stress Testing Methods in Body Structures,"SINCE theoretical and empirical engineering formulas do not always apply to automobile body structure, reliance must be put on structural testing to supplement available information. In this paper the author presents a technique for complete car structural and road testing in conjunction with body tests for such purposes as: 1. Aiding development of experimental body designs. 2. Assisting in the standardization of quality control methods. 3. Solving special problems in fabrication. 4. Furthering the improvement of body-frame unit structural efficiency. 5. Investigating the use of new materials. 6. Determining safety factor of body. The search for adequate methods of determining the safety factor led to the development of the roll-over test. It is accomplished by towing a car so that the wheels on one side go up a ramp at a 15-deg angle, and at a speed of 50 mph. The car is rolled in such a manner that the windshield header receives the greatest impact."
INSTRUMENTATION OF VIBRATION IN AN AUTOMOBILE BODY,"A short movie will be shown indicating the cars being tested for shake on the road and in the laboratory, and some of the equipment will be seen in operation. Next, eight slides will be shown and a detailed description will be made of each slide. The major context will be to show: 1. The functional arrangement of the equipment. 2. The method of interpreting the data for a single point under shake conditions. 3. The method of obtaining curves for multiple point studies. 4. The solution for a general problem."
TRENDS IN MODERN AIRCRAFT STRUCTURAL DESIGN,"Although the Electra structure is based on past good practice, its higher performance and use of prop-jet engines have injected certain new situations of interest to structural engineers. Such items include the new CAA gust criteria, loads created by prop-jet engine failure, development of the “No-Hazard” windshield, engine nacelle design loads, wing loads when taxiing with full wing fuel, fail safe and fatigue, the use of large die forgings, and the bleed air duct system used for de-icing."
PRINCIPLES OF NOISE REDUCTION,"THIS paper explains a few of the basic principles of the character of sound and the mechanism of human hearing. The author describes some simple experiments which demonstrate the relationship between intensity and loudness and the nature of harmony. He also points out the difficulties of accurately analyzing sound electronically, and the resulting importance of combining the finest electronic equipment with sharp, attentive human faculties. Five basic ways to reduce noise and the mechanics of each are described. The effect of these methods on the work of the sound engineer is indicated."
Acoustic Design and Performance of Turbojet Test Facilities,"THE high noise level associated with turbojet testing creates two noise problems: 1. The reduction of noise in the neighborhood of the installation to an acceptable level. 2. The protection of operating personnel from excessive noise. Desirable sound levels are established and, on the basis of these levels, specifications are written for the acoustic treatment of the turbojet facilities. The acoustic treatment must not only be satisfactory from the point of view of noise reduction, but it must also be able to withstand the very rigorous operating conditions. High-temperature and high-velocity flow of gases through the exhaust stack makes for these rigorous conditions. Designs which meet these specifications are discussed in this paper, together with performance data obtained on these designs."
Human Problems in Jet Air Transportation,"THE human problem with jet aircraft begins even before take-off, the author points out, with discomfort and loss of efficiency from noise, and ground injuries on the field or in repair shops. In the air, although noise and vibration in the jet plane are less than with the reciprocating engine, human tolerance is matched against other extreme forces of acceleration, direction changes, temperature and pressure variations. Through detailed examination of what happens to passengers and crew in the many situations that can arise to challenge human limitations, the author shows why he believes there is need for closer cooperation between the biologist and the engineer, and for better education of crewmen in the effective use of their equipment and in their own physical limitations."
SOUND and FUROR THE JET NOISE SUPPRESSION AGE,"BEFORE an evaluation of suppressors can be made or before a sensible discussion of suppression goals can be carried on, terms, conditions, and possibilities must be understood. A five-number system for evaluating suppressors is proposed. Methods of jet noise suppression undergoing general development today include frequency shifting, jet spreading, and jet velocity reduction. Basic types of jet spreaders and velocity reducers are shown and ratings given. Combinations of types have resulted in increased suppression in many instances."
Automobile Body Loads,"SINCE passenger-car bodies cannot practically be designed to meet the abnormal stresses of collision, normally needed rigidity is a major design criterion for the modern body. Bodies must be stiff enough, the author points out, not to respond easily to the excitation caused by vibration of the unsprung mass of wheels and suspensions, but not too stiff to ride comfortably. Recent trends toward more glass area and lower body height have increased the importance of determining body loads and structural requirements. Discussed here are some of the ways in which these factors are investigated, and the results which have been achieved."
LIGHTING THE MOTORBUS,"General considerations that affect the attainment of adequate lighting are mentioned, it being stated that proper lighting of the interior of a motorbus is influenced by limitations peculiar to the service, such as vibration, scant headroom, a restricted energy supply and relatively large voltage-variations. Available types of bus-lighting equipment are analyzed as to their suitability, from six different standpoints that are stated. “Glare” is defined and means of obviating it are suggested, inclusive of a discussion of desirable types of finish for the interior with regard to reflecting surfaces. The severe vibration produced by many motorbuses demands head-lamps of more rugged construction than that used for the headlighting of private cars. Eight essentials for motorbus head-lamps are specified. A very large percentage of the glare and poor illumination of the motor vehicles on the roads results from improper adjustment or the lack of any means for adjustment of the head-lamps. Tail-lamps, stop and direction signals, step-lamps, trouble-lamps, lights for the signs and marker-lights are discussed. Standard incandescent lamps are recommended for use. The most suitable type of electrical system for motorbus service is outlined briefly, consideration being given to the wiring needed to minimize voltage-drop, switches, lamp sockets, fuses, generator and voltage regulator."
The Satellite Airport System and the Community,"This paper presents an answer to the ground barrier problem. Studies have defined problems in the following areas: maximum terminal capacity, internal roadway systems, automobile parking, freeways and access roads, airfreight, and noise. To find solutions to the above problems, a satellite system of airports has been developed which will smooth out the interfaces with all other forms of transportation for people and commodities, and will disperse the volumes entering the system. In our satellite airport system studies, the Metroport, with short elevated runways capable of handling the new vertical and short take-off aircraft, has evolved. An elevated rail, and in some cases a subway system, travelling clear of ground congestion will be a vital link in the transportation network. The Los Angeles satellite airport concept is one of the best answers to bringing air transportation to all sections of the metropolitan areas."
Canada's Role in the Second Decade of the Space Age — Inner Space Supersonics,"This paper, presented to all types of Canadian engineers, has as its objective the stimulation of their interest in the many problems yet unsolved in the aviation industry. The paper describes briefly the SST programs - the British/French “Concorde,” theUnitedStates “Boeing2707” andtheU.S.S.R. “TU-144.” Then various engineering problems such as sonic boom, sideline noise during takeoff, cosmic rays, fuel consumption, reliability, and airport requirements, are considered. Finally, ways to reduce ground time are examined."
Passenger Car Ventilation by Design,"Favorable ventilating systems in passenger cars and their influence on the rate of air flow in the passenger compartment are shown. One example shows the pressure distribution along the centerline of the body and the differences in the pressure between possible body air inlets and outlets which determine the rate of air flow with any particular ventilation system. Several ventilating methods are shown which satisfy the requirements of increased air flow, reduced noise level and defined air flow in passenger compartment, prevention of water entry, and elimination of drafts. In view of the increasing desire for a reduction of noise level inside the passenger compartment, the noise created by the wind when the windows are opened or when the doors and windows are insufficiently sealed should be eliminated by specific ventilation openings."
Preliminary Studies of a Supersonic Business Jet,"This paper discusses two possible designs, an unswept trapezoidal wing model and an essentially delta wing model for a 10 passenger Mach 2.2 Supersonic Business Jet. The studies are quite preliminary in nature and the result of team efforts in two different Senior Aerospace Vehicle Design courses at the Georgia Institute of Technology. The philosophy of the course and the selection of this particular aircraft as a project design are touched upon briefly. The body of the paper compares the two designs, and discusses in an elementary manner their aerodynamic performance, engines, and propulsion systems; some of the design details; cost; and probable noise level, including the sonic boom problem. They are not considered solution aircraft, but the designs are believed to be fairly representative of what the resulting aircraft would resemble. The work is continuing through re-cycling and optimization of the performance by computer techniques."
Effects of The Super Sixty Series DC-8 on Airport Requirements,"A welcome relief to airport runway, taxiway, gate position saturation, and air traffic congestion is offered by the new Super Sixty Series DC-8, which now carries twice as many passengers per flight. Airplane operators benefit from substantially lower direct operating costs per seat-mile and more efficient utilization of pilot manpower in an area of growing shortage. These airplanes have a special family of problems in common with earlier jets, including community annoyance caused by noise, runway strength limitations, and the requirement for an increase in terminal people and bag gage handling equipment."
"Design, Manufacture and Marketing of Cabs for Industrial and Agricultural Equipment","This paper reviews what has happened in the cab industry since earliest developments and defines the “state-of-the-art” at the present time, pointing out areas of design, engineering, and marketing that should be investigated. Some of the new developments in cab design such as pressurization for dust elimination, air conditioning, and noise abatement are discussed."
Automatic Light Aircraft Readiness Monitor,"A study has been made of the feasibility of performing maintenance inspections on Army aircraft using automatic electrical methods. Sensing devices discussed are for vibration, temperature, pressure, liquid levels, interlocks, chip detectors, and engine speed. Evaluation of tests show that much work needs to be accomplished before electrical inspection is practically feasable."
Evaluation of Automobile Body Design,"The automobile body is a total environment. An evaluation of this environment should include consideration of: seats, vision, noise level, heating system, ease of entry, ease of maintenance, instrumentation, trunk space, exterior, and styling. These points and others are reported in an annual survey made by Popular Mechanics magazine. The owners' report is sent to drivers all over the country who evaluate their new cars on the basis of likes and dislikes. The tabulated results can be a guide of the engineer and stylist alike."
Delivering the Mail with Diesels - The Post Office Department Looks at Diesel Engines,"To determine to what extent diesel power should be introduced into the 60,000 truck postal fleet, a comprehensive evaluation-type study was undertaken by the Automotive Division of the Post Office Department. The study encompassed the complete range of truck sizes from the large 65,000 gcw tractor-trucks to the small 1/4-ton three wheel scooters. Considered in the evaluation were such factors as reliability, noise level, driver reaction and vehicle performance characteristics, in addition to the usual comparison of fuel consumption. Although the complete life cycle of the representative gasoline and diesel vehicles being studied is not complete, certain interim findings concerning vehicle performance and driver acceptance do support the trend to more general use of diesel powered vehicles."
Sonic Boom Problems And Noise from High Performance Propulsion Systems,The development of aircraft noise consciousness in its relation to the environments of persons in the airplane and on the ground is discussed. Measures to control aircraft noise in both connections are presented. The significance of environmental noise in the development of the supersonic commercial transport is considered.
Recommended Practices for Use in the Measurement and Evaluation of Aircraft Neighborhood Noise Levels,"SAE Committee A-21, Aircraft Exterior Noise Measurements, was formed in 1961 to develop recommended practices for use in the evaluation of aircraft noise as it relates to airport neighborhood annoyance problems. The general areas of interest to the committee include the measurement, propagation, prediction and subjective rating of aircraft noise. This paper discusses the evaluation of aircraft neighborhood noise levels and describes the subjective measures by which comparisons can be made. Included in the discussion are the recommended practices adopted by SAE and those that are being studied by Committee A-21."
RESILIENT MOUNTINGS for Passenger-Car Powerplants,THIS paper discusses the application of resilient mountings to passenger-car powerplants. Resilient mountings have a threefold purpose: 1. They isolate engine vibration and torque impulses from the rest of the vehicle. 2. They insulate the engine mass from incoming excitations due to road irregularities. 3. Nos. 1 and 2 must be accomplished without allowing the powerplant mass to get into synchronous vibration with any component of the vehicle.
Conditions of the Perfect Windshield *,This paper deals with the question of how windshields must be constructed and installed in order to provide the highest degree of protection for passengers in a crash. Material characteristics and mounting methods of laminated safety glass are discussed from the viewpoint of actual conditions (internal automobile dimensions and possible head-to-glass impact velocity) and concrete performance data are given. A test specification is also proposed.
Manned Spacecraft Structure Versus Unmanned Spacecraft Structure,The large difference between the total numbers of manned and unmanned spacecraft and their respective missions is discussed. The environmental and functional requirements having different effects on the two spacecraft types are described. The materials characteristics involved in those requirements and the resulting typical configurations are reviewed. It is concluded that vibration and pressurized gas containment have the outstanding influence on spacecraft structural systems. It is noted that new structural factors of safety have not been derived on the basis of any rational consideration of the design conditions for stability or pressure critical structure.
Moisture Protection of Window Lift Motors,"This is an evaluation and description of the methods and materials used to moisture proof window lift motors as applied inside automotive doors. An environmental test cabinet is described. The materials and methods were tested for their ability to seal, their resistance to abuse, their application to the motor housing, their resistance to lubrication, and their cost. The methods of moisture protection investigated were: drain holes, moisture proofing materials, and positioning. Considering all aspects, gasket seals between the motor frame and the housing proved to be a superior way to protect motors from water damage."
United States Supersonic Transport Development Program - Sonic Boom and Noise Research,"Performance objectives for the United States supersonic transport airplane provide for minimum sonic boom levels, and engine noise levels no greater than generated by current large subsonic jet aircraft. A national program of sonic boom research has been pursued by the NASA, DOD, and FAA. A National Academy of Sciences committee is now providing guidance and counsel for this effort. Major recent sonic boom flight research programs, which have yielded extensive data, were the study of public reaction to sonic boom in the Oklahoma City area last year and the structural response program recently concluded at the White Sands Missile Range, New Mexico. Findings in these two sonic boom programs are presented. Engine noise, which has received attention since the inception of supersonic transport research and under design contracts, may be less for the SST than for current large subsonic jets under most conditions. A discussion of this subject is presented."
Road Noise Control for a Car with a Tray Construction on Chassis,"This paper describes experiments to find the source of the road noise in automobiles and methods for correcting it. To find the major source of road noise, the time lag of the sound waves was measured. Characteristics of a tray frame construction car were found by comparing the vibration modes of its frame with those of body-frame and unit construction cars. As a result of experiments, it was found that the tray frame construction car combines desirable features of both body-frame and unit construction cars."
AUTOMOBILE FINISHING-VARNISH,"Annual Meeting and Detroit Section Paper - As the success or failure of the finish of an automobile depends largely on the finishing-varnish, a plea is made for more scientific analyses of the problems of automobile finishing and more care in selecting and applying a suitable varnish. The qualities to be desired in a finishing-varnish are divided into two classes: the shop qualities and the service qualities. The shop qualities include color, body or viscosity, working, flowing, setting, hardening, fullness and the safety of working. The service qualities, or those that enable the varnish to withstand the various conditions of use, include resistance to break-down under the chemical action of the actinic rays of sunlight, to the destructive action of moisture and the alkalis in mud and soap, to expansion and contraction, to vibration and to abrasion. The three most important factors in estimating the service-giving qualities of varnish are said to be elasticity, moisture-resistance and the film factor. Each of the various terms mentioned is carefully defined, analyzed and explained. Among the constants that must be determined, either for checking uniformity or for use as bases of tests, are the non-volatile content, which is the starting-point in the test for elasticity and in computing the film factor, or thickness of the dried film; the ash, the flash-point and the acid number. An empirical formula is derived by which the thickness of the dried film can be estimated with accuracy; and in a series of appendices the details are given concerning tests for the drying, the safety of working, non-volatile content, ash, flash-point and acid number; the Kauri reduction test; and tests for moisture and alkali resistance."
SPRING-MOVEMENT AND VIBRATION STUDY OF CARS IN ACTION,"Previous efforts to obtain comfortable riding-qualities for passenger-carrying automobiles are mentioned, and a device that combines a recording seismograph and a spring-action recorder is illustrated and described, since such a device is essential in conducting investigations of this character. Methods governing the use of the device when studying spring action and chassis vibration are outlined, and the results obtained are presented graphically and discussed. Several unique features characterize these tests and are worthy of consideration, not only because of the results obtained thereby but as being good illustrations of what can be accomplished by substituting unusual and perhaps spectacular methods in special instances for ordinary practice that has failed to produce some desired result."
The Chassisless or Unit-Car Question,"THE experience gained over a period of many years in the development of light-weight, high-strength structures is now finding its way into the bus industry. Investigation of present-day bus operations showed the need for a road vehicle that would carry the greatest possible payload of passengers with a smaller horsepower engine without dragging along a load of dead weight and useless structure that would eat up gasoline instead of miles. A motor coach is now available in which are incorporated aircraft materials, design, and construction features resulting in a vehicle that is approximately 1000 lb. lighter than the lightest conventional design with the same engine horsepower and seating accommodations. Motor-bus operators today can reduce costs by the use of light-weight equipment provided there is no sacrifice of strength and reliability. They must also meet the ever-increasing demands of the public for quietness, comfort, absence of vibration and engine odors - all of which can be accomplished by placing the engine in the rear which automatically gives a better distribution of weight than has heretofore been possible with the front-engine design."
Cab-Over-Engine Trucks - Their Status and Advance in Design,"DEPENDING upon the location of the front wheel, the door and step are placed either at the front or back of the cab. Some designs incorporate a protruding “hood” portion, whereas others extend the cab fully forward. The engine compartment is either immediately back of the radiator or under the cross seat. The floor and seat heights are relatively higher than in the conventional truck, and better visibility is obtained. The engine hood is well insulated for heat and sometimes for sound as well. Most powerplants are removable readily for major repairs although, in most instances, major maintenance operations can be done readily within the cab. Front axle treads have been increased in order to give greater stability on the road as well as to avoid an excessively large wheelhouse. The change in weight distribution has called for considerably more study on braking distribution. The shortened wheelbase requires a more accurate location of the fifth wheel in tractor-semi-trailer service; has emphasized the importance of the steering-angle conditions of the front axle; and has brought riding qualities to the fore. Specifications and dimensional data accompany the paper, as well as drawings of typical layouts showing the cab, engine, and front-axle relationships."
AUTOMOBILE BODY DESIGN,"The author first considers the style and arrangement of the seats, the position of the rear axle as affecting the rear kick-up in the chassis frame, and the position of the rear wheels as determining the distance from the back of the front seat to a point where the curve of the rear fender cuts across the top edge of the chassis frame. The location of the driver's seat and of the steering-wheel are next considered, the discussion then passing to the requirements that affect the height of the body, the width of the rear seat, and the general shape. The evolution of the windshield is reviewed and present practice stated. Structural changes are then considered in relation to the artistic requirements, as regards the various effects obtained by varying the size or location of such details as windows, doors, moldings, panels, pillars, belt lines, etc., and the general lines necessary to produce an effect in keeping with the character of the car. The design of the wings or fenders, the weight, producing effects of light construction, and the use of aluminum are also considered, the conclusion reached being that the design of the highest type of automobile body should always be based primarily upon a high degree of practicability."
Automobile Engineering Progress,"GENERAL DESIGN and detail mechanical developments that have been made in the last year and incorporated in automobile, truck and motorcoach models for 1932 are reviewed by the author, who also points out noticeable trends in a number of directions. He deals in order with the cars as a whole and with each major component, from the powerplant to the tires and body, as found in many leading makes. Decision of the industry not to announce the details of new models until the end of the year, at or immediately before the opening of the New York Automobile Show in January, interfered with the presentation at this time of a complete picture of all the improvements made in American motor-vehicles, but enough information is believed to be given to show the more important developments and the ways in which the automotive engineers have responded to the desire of the times for greater refinement and efficiency in automobiles. The improvements are reflected in better appearance; greater comfort; reduction of air resistance, noise and weight; insulation against heat from the engine; easier control; improved visibility; longer service life of some parts; avoidance of vapor lock; enhanced safety; increased operating economy; and simplified servicing in some cases."
The Aircraft Trend in Body Design from the Aircraft Viewpoint,"AIRCRAFT have taken more from automobile design than they have given, but they can now repay much of the obligation without necessarily transgressing the requirements of production economy and reasonable design stability. Some of these possibilities are: (1) Improved streamlining of necessary exposed parts, particularly underneath, and incorporation of other accessories in the general body lines. (2) Use of curved glass in the windshield and lightening of all window material. (3) Reduction of the frame to the status of an assembly unit, with structural significance only in combination with the body. (4) More effective distribution of flange material around the doors. (5) Lightening of skin by use of internal stiffeners, particularly on top. (6) Development of a smaller, more efficient radiator and lightening of various engine parts. Most important is the mental attitude behind the work. Phenomenal production economy has been attained because almost every man in the industry has concentrated on it. Worthwhile weight and drag reduction would result if even one competent man were assigned specifically to that duty. Lightening, with streamlining, is a beneficent cycle that permits still further lightening, resulting directly in substantial operating economies and, indirectly, in lower production cost."
New Technique for Noise Reduction,"GREAT simplification of understanding and unusual results in production often follow new approaches to old problems. When noise problems are stated in terms of the familiar physical units of pressure, velocity, weight, and stiffness, basic ideas are obtained which can be applied directly to practice. In this way, most of the mysteries and the contradictions of noise problems are eliminated. In their elements, noise problems involve only simple physical factors which are understood easily, and which can be measured with available equipment. Similarly, the solutions involve the straightforward application of known and definite engineering principles. Although simple in their elements, most practical noise problems are very complex because of their combinations. Often much ingenuity is required to measure the physical characteristics of the noise which determine the human impressions obtained from it. Such determinations can be made by proper modification of the attack and the measuring equipment, and are the key to successful noise reduction. This paper gives a classification of the various means of quieting, and outlines the technique of applying them to production. The viewpoint is quite different from that usually employed, and the practicability of the method is illustrated by examples of actual jobs."
A Designer-Manufacturer Viewpoint of Transport-Aircraft Needs,"ONE of the most essential points in the development of any airplane is the necessity for complete cooperation between the operator and the contractor in regard to necessary and desirable features to be incorporated, and this is particularly important for a commercial-transport airplane. This coordination was carried through to a remarkably efficient culmination in the development of the Douglas transport for T.W.A. Points discussed include arrangement of cabin and cockpit, seating facilities, upholstery, elimination of vibration, heating and ventilating, soundproofing, toilet facilities, lighting, vision and maintenance. The care with which all these practical considerations were worked out is discussed, and special emphasis is laid on the important points of soundproofing and maintenance in which a remarkable degree of perfection has been attained. This care and attention to details is well worthwhile and only in this manner can a really successful transport be designed incorporating all the technical and practical knowledge of the operator, manufacturer and other specialists who assist in perfecting the various installations."
Relation of Headlamp Construction to Headlamp Roadway-Performance,"HEADLAMP construction is presented in summarized form, twelve needful factors being stated by the authors. Accelerated mechanical tests, which are designed to give within a few days results of what may be expected to take place after several years of road service, are conducted in the Headlight Laboratory of the University of California. These are described and illustrated under the headings: Vibration, durability, moisture, dust and electrical insulation, and the results are stated. A few correlation tests are commented upon. Headlamp vibration is treated at length, together with an analysis of headlamp vibration-characteristics, and a differentiation is made between vibration due to the engine and that due to roadway shocks. Measurement of headlight glare upon the roadway was made by obtaining continuous records of the illumination of the driver's eye from opposing cars or other equipment, the apparatus used including a photoelectric cell mounted inside the windshield in a direct line with the driver's eyes, an amplifier specially designed to cover the range of illumination and an oscillograph for obtaining a photographic record. Partial results of these tests are given. The general conclusions reached are set forth in six divisions, the last being that 0.07 ft-candle at 100 ft. is indicated as a criterion of glare."
Practical Noise Treatment of Automobile Bodies,"THE noise problem in the automobile body is complex and encompassing due to the fact that no single angle of attack is either complete or by itself sufficient to produce the desired results. Such results must be in the final analysis appreciable to the passenger's ear. For practical purposes and to meet the requirements of the industry, the problem has been divided into two parts: (a) To secure better results or greater improvements, for the same cost or less, by finding the best materials suitable in the general body-insulation practices of today. (b) To secure a complete and well-balanced job, involving a broader application of materials found to be most practical and economical, or to develop unusual products possessing unusual properties and larger capacities to function properly under given conditions. The instruments and very thorough method used are just means to an end, as in other fields of research or experimentations in which so many here have played a part. Or we may say that he who rides and hears, may also ride and see what he hears, and what we see can readily be recorded accurately."
Design Criteria for Turbomachinery Periodic Structures to Improve Tolerance to Inflow Distortion and Resonant Oscillatory Flows,"The purpose of this paper is to discuss typical problems caused by pressure waves of large amplitude propagating in a circumferential direction in turbomachinery. Opportunities for design control of cascade resonance as a means of protecting turbomachinery from these pressure waves are presented. Some of the critical areas are compressor rear frame diffuser and main combustor instability, afterburner screech, shock wave flutter instability of high-pressure ratio, variable-geometry jet nozzles, compressor stall, compressor stage 1 blade fatigue failures, and labyrinth air seal fatigue failures caused by flexural vibration of the thin walls."
Booster Engines for Commercial Airliners,"This paper discusses some of the fundamental advantages of using a special booster engine (s) for augmenting the takeoff thrust of commercial transports. The additional thrust provided by this principal offers increased route segment versatility by providing a wider range of tradeoffs in the takeoff distance, payload, range, safety, and noise level patterns for a particular aircraft. It further describes the flexibility in configurations that this principle provides the manufacturer for a given model. Also discussed in general terms is how the limited flight envelope and short operating time required for booster engines can be used to effectively reduce the engine's weight and volume."
Ford “S” Frame,"Since statistics indicate that front impact is the major accident type, Ford has been studying energy-absorbing structures for some time. Early designs such as the “ball and tube” and “rail splitter” were discarded in favor of the “S” frame. Details of the design approach and testing are given in this paper. Design objectives were increased effective collapse distance, compatibility with production practices, and maintenance of satisfactory noise, vibration, and harshness levels. Safety objectives are improved passenger compartment integrity and reduction of seat belt loads. Barrier crash tests at 30 mph (equivalent to collision into standing vehicle at 50 mph) were used to evaluate the design of the “S” frame. Results of testing indicate that occupant restraint with seat belts, combined with front end structural improvements, offer the most promise for injury reduction during service front impact accidents."
747 ENGINE INSTALLATION FEATURES,"New approaches to problems such as noise, temperature control of accessories and equipment in the nacelle, as well as improved safety features, are necessary in a modern high by-pass engine installation. The means of supporting the engine, cowling design, and maintainability features combine to improve the state of the art that a more economic airplane will result."
Producing a Quiet and Comfortable Cab,"Farm tractor cab design with respect to quiet comfort and convenience is discussed. The areas of visibility, accessibility, environmental control, and noise suppression are investigated. Various approaches to accomplish optimum conditions in these areas are analyzed, components are evaluated, and design recommendations are made."
Methods and Problems in Noise Reduction on High Speed Diesel Engines,"This paper describes a newly constructed research facility which was specifically designed for noise reduction work on internal combustion engines. Various approaches for reducing engine noise are discussed, and a method which permits locating individual sources of structure-borne sound is reviewed. A measuring system for airborne sound, radiated from the engine surfaces, is described. Some new findings and new problems encountered in noise reduction work are discussed."
Crash Research for Vehicle Safety,"The Impact Sled, a full-scale laboratory facility which simulates vehicle accidents, has been in use at the General Motors Proving Ground since late 1962. This paper describes the facility and supporting instrumentation, and reviews some of the many types of tests that were run in the first year of operation. These range from tests of complete vehicles loaded with passenger dummies to tests of single components such as seat belts, seat adjusters, door locks, and windshields. This new research tool, which produces results comparable to those of the classical barrier impact test, has proved to be a valuable and versatile addition to the automotive testing facilities at the Proving Ground."
Aerodynamic Effects on Automotive Components,"The range of automotive components that are affected by air flow around the car is surveyed, with examples of the application of aerodynamic knowledge to brake and engine cooling, wind noise, dirt accumulation, wiper lift, body ventilation, and air leakage. Air pressure distribution patterns over an automobile are shown along with air flow visualization techniques."
Recent Developments in Penetration Resistance of Windshield Glass,A twofold improvement in penetration resistance of laminated safety glass for use in vehicle windshields has been achieved. A new test procedure has been established which will provide better correlation of test conditions to accident conditions than present tests do. Present windshield material and the new safety glazings are compared.
Airport Compatibility with the SST - Problems of Ground Support Equipment,"The compatibility of a supersonic transport with 15 international United States civil airports is examined in the principal areas of: terminals, passenger handling, and ground support equipment; runway length and pavement strength; and airport and community noise. Some new support equipment and facilities will be required although they are considered to be evolutionary in nature rather than requiring radical departures from current design. Runways and pavement strengths are generally acceptable as they exist today. Noise, both in the terminal areas and in the surrounding community, is expected to be equivalent to, or less than that of contemporary subsonic jet transport aircraft."
Automobile Driver Eye Position,"This paper reports results of a driver eye position survey made to provide the automobile industry with standardized data on driver eye location. Coordinate anthropometric measurements of eye position and top of head were recorded on film by a special photogrammetric technique. Data were smoothed into elliptical tangent cutoff percentile contours referenced to car body inch-lines and to points on the manikin. Results revealed a new shape to the driver’s eye position zone, compared to the area outlined in SAE J906, Glazing Manual."
Efficiency in the Use of Shop Space,"The growth rate of motor common carriers of general commodities has been greatest from 1950–1960. Being a service business, the increased facilities required, primarily the freight terminals and garage buildings, necessarily lagged behind the business being handled. Many factors must be considered before construction is begun. Planning necessarily includes geographical location, adequacy to handle the vehicles that will be assigned for maintenance, design of the building, and the extremely difficult matter of cost. The author’s concept of the most efficient garage building is that it be rectangular in shape, have a flat roof, parallel service bays of a standard width with corresponding power-operated overhead doors, space heaters of the self-contained type mounted overhead, storage space located on second floors, and all stationary shop equipment mounted overhead or under the floor. Most important though is the efficient use of all floor space."
An Approach to the Isolation and Control of Vibration in Light Business Aircraft,"This paper presents an approach utilized by a light business aircraft manufacturer in resolving vibrational problems. The discussion relates the principle sources of vibration; objective briefly explores the consideration of priority in the operational range of the aircraft. The approach phases--preventive measures, theoretical application, and practical application--are illustrated through an actual vibration problem solution. It is concluded that this approach has proved satisfactory and that the importance of the practical aspect cannot be underestimated."
An Automotive Living Room on wheels,"The family car of a not-too-distant tomorrow will be “an automotive living room on wheels.” An air-conditioned vehicle equipped with television for back-seat riders, pull-out tables for games or dining, vanity-table and clothes-storage compartments, seats that convert into luxuriously upholstered davenports, or serve as sleeping couches when the car's recessed window blinds are pulled down. The power plant and driving line will be simplified to one of three procedures: a front engine front drive, a rear engine rear drive, or a turbine or fuel cell all-wheel drive. The entire design will be based on the largest possible “living room” mounted between the most reasonable wheelbase and without noticeable overhang."
A Shipbuilder's Views on River Towboat Vibration,"This paper discusses causes, prevention, and possible corrective measures for river towboat vibration. Also discussed is the problem of resolving the amount of vibration acceptable to both owners and builders before corrective action is indicated in a specific vessel. The author suggests that sufficient research into towboat vibration be accomplished to establish some numerical parameters that can be used as standards of acceptance for vibration limits."
Wind Noise - A Practical Approach,The principle cause of objectionable wind noise in the modern automobile is small air leaks in certain critical areas. The aerodynamic shape is insignificant in overall wind noise. The critical areas in order of importance are: 1. Vent window and door to “A” post sealing from the roof rail to about a foot below the beltline. 2. “C” post area at beltline. 3. Upper rear of front door area. 4. All other areas from roof rail to a foot below the beltline. Conclusions reached after extensive testing show that wind noise can be eliminated by good sealing about the doors and windows.
Vehicle Vertical Vibration and Tire Performance,"In the first part of this paper methods recently developed for the study of the oscillations of running vehicles are described as well as two types of analysis. Some information about the apparatus used for recording and analysis are given. In the second part the results of the analysis of the vertical vibration of a car fitted with three types of tires running on various types of road at various speeds are presented and discussed. Finally, in the third part, the possible influences of tires on the vertical vibration of the vehicle are surveyed. The viscoelastic deformations of the tires cause middle frequency oscillations which are transmitted from the tires to the unsprung masses and to the car body."
THE POSTWAR CAR AND THE A-BLAST…WHAT ARE THE ODDS?,"WHAT would happen if an atomic bomb were to explode at noon tomorrow without warning of any kind? Would the automobile turn out to be a death trap for many of us or would it offer as much protection as the ordinary building? Would there be any advantage in having the car turned away from the center of the blast or to having the windows rolled down? Would it be safer to crouch down on the floor of the car at the first sign of an atomic explosion? Would it be safe to enter our cars as soon as the first effects of the explosion have subsided? Would the cars run? It was to find the answers to some of these questions that a group was invited to observe an experiment at the Nevada Proving Ground of the Atomic Energy Commission. This group - which became the SAE-FCDA Advisory Committee - wrote the accompanying report, which tells about the experiment and some of the things that were learned. A. L. Haynes of Ford is chairman of the committee. Other members are: R. B. Alexander of Packard, William Christensen of Nash-Kelvinator, V. B. Corey of Willys, N. F. Hadley of Chrysler, E. J. Martin and M. V. Muzzy of GMC, W. W. Smith of Studebaker, A. D. Wagner of Hudson, and R. C. Sackett of SAE, secretary."
A TECHNIQUE FOR DETERMINING THE OCTANE NUMBER REQUIREMENTS OF COMMERCIAL VEHICLES,"Despite the size and importance of the fleet market, refiners have little information on the antiknock requirements of commercial vehicles. Considerable interest has been displayed in obtaining reliable data in this area. Some road survey data have been obtained in the past; however, truck engines are more prone to high-speed knock due to today’s more sensitive fuels and higher governed speeds. Knock under these conditions is more damaging and cannot be heard due to the masking effect of the high level of vehicle noise on the road. A chassis dynamometer technique has been developed to overcome this noise barrier and thereby provide realistic octane requirement data. Data obtained with this technique on commercial-type fuels were used to construct what is described as an “octane requirement map”. This map extends the usefulness of the data and is a unique and effective means of expressing octane requirements, particularly how requirements are related to the sensitivity of the fuel. The map is also used to describe a new concept in determining relative engine severity."
"Automobile Side-Impact Collisions, Series II","Engineering methodology and research techniques, applied to 12 intersection-type automobile collision experiments, provided data on four speeds of impact and on three positions of impact. Anthropometric dummy motorists provide collision force and kinematic data for several conditions of restraint. Advanced photographic equipment identify new approaches to solution of the motorist collision injury problem. Specific data include tri-axial acceleration patterns for motorist head and chest and for car passenger compartment; identification of many factors associated with door latch failure and motorist ejection; demonstration of protection provided by the shoulder strap and lap belt combination; preliminary findings on tempered side window glass breakage and related head impact accelerations; collision dynamics and why modern car design has reduced probability for intersection collision roll-over; car collision deformation, skid patterns, and cost to repair damages are given for these controlled exposures. Successful programming of collision transducer patterns for data reduction by 7090 computer also is described."
SST Operations and Maintenance Considerations,"The SST pilot will have at his command more automatic equipment and better readout and displays to control noise level near the airport, to program the climb for minimum sonic boom, and to operate the airplane to lower weather minimums than on any previous transport. Yet, Boeing believes the typical senior airline captain will make the transition without any difficulty. The SST mechanic will have new and larger facilities, will handle bigger and heavier equipment, will learn to maintain airplanes still hot with residual heat, and will learn to maintain and repair that new metal titanium. Yet, the mechanic will find the SST maintenance and repair the best planned and organized of any airplane program to date."
The Body Engineer's Role in Automotive Aerodynamics,"Aerodynamic streamlining is assuming greater importance with our sustained driving speeds on new expressways. Benefits of streamlining include reduced wind noise, reduced lift and better stability, improved acceleration at passing speeds, higher cruising and top speeds, better fuel economy, and reduced initial costs. Basic principles of aerodynamics for automobiles are presented. Application of these principles are discussed and depicted for different types of automobiles and a tractor-trailer unit. Tables, formulas, and examples are included. Trends show aerodynamics as a factor of increasing importance for the automobile. It is suggested that a joint training program be initiated for body engineers and aerodynamicists with classroom studies based on detail design problems."
A New Look at the Aircraft Noise Problem,"This paper presents an analysis of the airport community noise problem, based on the assumptions that some significant adjustments will be made to reduce the impact of aircraft noise on the community, and that these adjustments can be made in an atmosphere of cooperation among engine and airplane manufacturers, airline and airport operators, and communities. Such cooperation can make available combined know-how to arrive at adjustments that will cause minimum loss to all interested parties."
Control of Double Images in Automobile Glass,"This paper first examines the optical principles involved in the formation of double images so that glass may be evaluated for this property in the design stage of automobile windshields. It then describes a new instrument, the local curvature and wedge meter, which has proved to be useful in determining the extent to which each of the three factors of curvature, inclination, and wedge has contributed to the presence of double images."
Silent Mercury Rankine Cycle Power System,"A silent mercury Rankine cycle power system is under development at TRW for U. S. Army Mobility Command's Engineer Research and Development Laboratories, Fort Belvoir, Va. The 3 kwe SCAP (Silent Compact Auxiliary Power) system is a power generator unit designed for various hydrocarbon fuels. The main advantages are portability and the inaudibility at 100 ft with a low ambient noise level. The system consists of a mercury boiler, a high-speed mercury driven turboalternator pump unit, an aircooled mercury condenser, and necessary system controls. Since this system converts heat through a closed loop mercury Rankine cycle engine into useful electrical power, the design is adaptable to burning indigenous fuels. A complete 3 kw useful electrical output system burning hydrocarbon fuels will weigh 125 lb and have a fuel consumption of 6.35 lb/hr."
Lead for Noise Control,"A variety of forms of lead and leaded materials for controlling noise and vibration is available today. These forms are classified by type and use, and the theory of their performance is examined cursorily in this paper. To describe the application of these materials for acoustic purposes, five examples are given to show their effectiveness in reducing sound levels."
Electrical Discharge Machining in Production,"Republic Aviation Corp. had a manufacturing problem with drilling the speed brake door of the F-105 airplane. The door is composed of annealed and heat treated Rene 41, Inconel X and titanium. To overcome this problem, electrical discharge machining was utilized to produce required holes, resulting in significant cost savings over traditional methods."
Injury in Non-Fatal Accidents *,"The research paper presented here is the result of an investigation by a medical-engineering team. The study applies techniques of experimental automobile-collision injury analysis to human injuries resulting from accidental collisions. The accident characteristics, observed injury patterns, and human kinematics are presented and analyzed. The study emphasizes injuries sustained from windshield glass. Present glass characteristics are discussed and suggestions based on the cases presented are made regarding future glass technology."
Aerodynamic Wind Throb in Passenger Cars,"Most automobiles, at certain speeds with at least one window open, develop a pulsating pressure which is felt mainly through the ears and is objectionable to the occupants. While this “aerodynamic wind throb” is noticeable over a range of speeds, there is a fairly pronounced peak in the effect at one speed. This problem is studied analytically and experimentally. It is established that the car is a dynamic system consisting of a Helmholtz resonator excited by an edge tone. It is shown that the trouble can be corrected by changing the natural frequency, minimizing or eliminating the excitation, or increasing damping of the system."
The WHY and HOW of THE RUBBER-TIRED RAILROAD-COACH,"Railroads are facing a crisis in operating costs, the urge toward reduction of unnecessary weight has become widespread and the crusade for noise abatement is no longer to be denied, according to the author. The pneumatic-tired railroad-coach not only answers these requirements, he says, but anticipates a demand for a new traveling comfort. The desire to rubberize railroad equipment is old but much fruitless research has resulted from directing it chiefly toward solid-rubber or cushion tires. Road and rail surfaces present entirely different problems so far as the tire is concerned. No uniformity of conditions obtains on highways but rails are even and smooth. A badly aligned joint such as would wreck a metal wheel makes no impression on a pneumatic tire. As simple as the tire problem may seem, its solution represents years of courageous and skillful research on the part of the Michelin company in France. Out of this has been evolved a rail-car tire which has a life comparable with that of tires in highway service and therefore is commercially acceptable. Facts from tire-performance data are stated and it is shown that light coach weight is the major need. The Budd-Michelin rail-coach is described and also the Reading-65 rail-coach. Weight comparisons are made and rail-coach body-design is discussed, as well as cost of weight."
The Place of Sound Measurements in Automotive-Noise Reduction,"THE desirability of measuring sound by soundmeter, rather than by listening with human ears, is expressed by the author, who states that soundmeter measurements indicate definitely just what components of noises must be reduced and also just what has been accomplished by any given change. Usually, they may be taken so as to indicate the part responsible for the noise, and even the nature of the defect. He then considers some fundamental characteristics of human ears and of various sounds. The apparent inconsistencies of the mass of data obtained from soundmeter measurements made in connection with practical noise-problems are explained, and the physical problem of what soundmeters measure is presented, together with a discussion of the subject of sound pressure and the use of the decibel scale of sound measurement which includes definitions of the various terms and units employed. The psychological problem, that is, the interpretation of sound measurements in terms of ear sensations, is presented at length and followed by a summary. The practical problem, that is, the technique of noise reduction, is analyzed also, quieting methods are suggested under seven specific headings, and it is stated as a conclusion that sound measurements obtained with measuring instruments are an indispensable aid in achieving logical noise-reduction."