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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. |