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Car Crash Tests of Ejection Reduction by Glass-Plastic Side Glazing | 1983 ejection statistics are reviewed; half of the passenger car ejections, some 36,000 people of whom 5,346 died, are through glazing areas. Previous work has shown the remarkable strength of thin plastic coatings, developed for windshield anti-laceration applications, when applied to the inside of tempered glass side windows, in reducing ejection. In the present work, two tests were made, each with the NHTSA Moving Deformable Barrier (MDB) at 39 mph and all four wheels turned at 26 degrees, striking a stationary Volkswagen Rabbit in a perpendicular impact. The Alfred I. DuPont de Nemours Company provided the plastic coating on tempered glass side windows. The plastic layer extended beyond the sides and top of the glass to be wrapped around steel strips bolted to the window frame. On vehicle impact, the tempered glass broke, but the pieces were held in place by the plastic layer, which then deformed outward as a “safety net” with head contact. In the first test, with a low and short striking vehicle hood line simulation, the top of the door bent out as the bottom was pushed in, and the head bulged the glazing out to hit the elevated base plate of the MDB, although the “safety net” held. In the second test, with a more typical vehicle hood line effect simulation, the “safety net” again held, giving a HIC of 616. A window design to allow window up and down motion with the plastic layer movably secured with a “T edge” in the window channel is under construction. An eight inch sphere Glazing Test Device is being developed, with a skin simulation / chamois coat on the lower hemisphere for laceration measurement, accelerometers for Head Injury Criterion (HIC) measurement, and a weight variable from 10 to 20 to 40 pounds, for ejection reduction measurement. This paper presents the views of the authors, and not necessarily those of the National Highway Traffic Safety Administration (NHTSA). The numbers in parentheses are the references, listed at the end of the paper. This paper is dedicated to the memory of Henry H. Wakeland, late of the National Transportation Board, who was instrumental through his work in New York in establishing government efforts to build experimental safety cars, and to the memory of William Haddon, Jr., M.D., late of the Insurance Institute of Highway Safety, who taught the world that automobile safety is one of the most important areas of preventive medicine, and that cars could be built, passively, not to harm. Both of these giants of automobile safety research died in early 1985. |
Ground Testing Approach for the B-1B Bomber | Existing methods for production ground testing the B-1B would create an undesirable and cumbersome work environment. The noise generated by the equipment along with hoses, cables and ducts on the floor produce a safety hazard. The information presented here deals with a new approach to meet the aircraft delivery rate requirement. Goals were established and a review of existing methods provided the “stepping stones” to the solution. The use of high technology computer applications is discussed along with the equipment types used on the B-1B bomber. This is the first automated approach to ground testing and checkout of complex aircraft mechanical systems. |
The NCSU Low Speed Boundary Layer Wind Tunnel | Procedures employed for the design of a new low speed boundary layer wind tunnel are described. The tunnel is a semi-open circuit facility for the study of large scale two-dimensional boundary layers with or without pressure gradients, A large plenum box is used as a replacement for a diffuser, 90 degree turn and noise attenuation chamber. The modular test section is seven meters long and capable of velocities from 5 to 33 m/sec. Experimental data to evaluate the tunnel performance are also described. |
An Application of Structural-Acoustic Analysis to Car Body Structure | In order to calculate efficiently the characteristics of car body vibration and the acoustic characteristic of the passenger compartment, a structural-acoustic analysis system, ‘CAD-B’, was developed. This system divides the body into three components - front body, main cabin and rear body. The characteristics of front and rear body vibration are expressed in modal parameters. The vibration characteristic throughout the car body is then calculated through the building block approach, while the main cabin remains in finite elements. A good agreement in eigen pairs was seen between this approach and the conventional finite element method. As for the passenger compartment, it is divided into finite elements and its eigen pairs are calculated. Then by linking body vibration with the acoustic characteristic of the passenger compartment, sound pressure in the passenger compartment is calculated. Since in the CAD-B system, the contribution of each panel vibration to sound pressure is calculated and displayed, the parts of the panel to be deadened are derived quickly. This approach has been applied to the problem of road noise reduction, and resultantly, interior noise could be reduced by using only a small quantity of sound deadening material. Some floor panel modifications to reduce noise were also made. |
Hem Flange Evaluation of Corrosion Performance | Field or service testing is the best procedure for evaluating the corrosion resistance of any material. However, in the development of a new product, complete service testing and long atmospheric exposure are impracticial due to the time required to develop data. Historically, the accepted method for accelerated testing has been the ASMT-B117 Salt Fog Test. Unfortunately, many investigators have found that salt fog test results do not correlate with field performance. For example; a light weight electro galvanized steel would be unacceptable based on only salt fog results, while field experience shows it to be marginally acceptable for a three to five year period. With a goal of approximating the conditions inside a car door, an investigation was undertaken to modify the current exterior paint scab cycle test to more closely match actual field conditions. This paper will cover how we developed our cycle test and correlation of our results with actual automotive performance. |
A Study of Vehicle Interior Noise Using Statistical Energy Analysis | The noise and vibration of an automotive vehicle is studied using Statistical Energy Analysis (SEA). Three sources of interior noise - the engine, tires, and air flow - have been measured and used as inputs to the SEA model. The flow of acoustic energy through various structural components is calculated in order to determine the dominant paths of noise transmission to the passenger compartment. The predicted interior noise levels are compared to those measured under different operating conditions. The SEA model also evaluates the expected variation of the interior noise as the result of changes in the design configuration of the vehicle. |
Unconstrained Layer Damping and the Use of Modified PVA as a High Efficiency Lightweight Material | A lightweight polymeric visco-elastic sheet material has been developed called ‘Dedpan’ (thickness 600 micron, surface weight 1.25 Kg/m2). It exhibits excellent vibration damping performance when used as an unconstrained layer on sheet metal panels. Geiger plate decay rates of 26 dB/sec have been measured. The sheet is flexible, non-toxic, and meets automotive and building flammability specifications. The material composition is stable under paint stoving conditions (temperature up to 200°C), and the product has a tendancy to drape form to underlying structures when hot. These properties make it ideally suitable for the vibration deadening of automobile body panels. |
Motorist Head and Body Impact Analysis, Methodologies and Reconstruction | Motorist impact marks and embossments provide valuable data relating to evaluation of injury, crash energy management, occupant positioning and collision severity. Research techniques presented enable analysis of these impacts. Biomechanical techniques for motorist head impact analysis are presented along with static crush calibration and dynamic impact replication of passenger compartment head dents. Evaluation and identification of occupant induced marks on restraint systems are discussed as well as determination of who was driving. Ejection findings of the fifties and sixties are clarified by case studies that show how vehicle design changes may switch the portal of ejection from doors to windows. |
Evaluation of Vibration with Respect to Human Response | Methods of quantifying vibration with respect to human response are fully defined. The procedures may be applied to all types of vibration: multiple-axis and multiple-input motions which are steady-state, random or transient. The procedures are based on experimental research and have been applied to predict the discomfort, annoyance, health risks, interference with activities and motion sickness associated with vibration measured in a wide range of environments. The general method involves the assessment of 12 axes of vibration (the 3 translational and 3 rotational axes on a seat surface, the 3 translational axes at the seat back and the 3 translational axes at the feet). The method may be simplified so as to include only those axes of interest in specific environments. A scale of approximate discomfort, an ‘action level’ guide to the prevention of health effects, magnitudes of vibration which may interfere with activities, and a means of predicting the probability of motion sickness are provided. In all cases the frequencies, axes, locations and durations of the motions responsible for adverse effects can be identified. The application of the procedures to evaluate measurements in vehicles, assess computer predictions of vehicle vibration and optimise seat dynamics is described. |
Occupant Comfort Requirements for Automotive Air Conditioning Systems | This paper will describe - 1. Occupant comfort levels of 7 production vehicles when evaluated under “real world” owner test conditions, 2. Effect of film on glazing surface for interior vehicle temperature. The stylist who designs vehicles to sell must consider what imposition they have placed upon the a/c engineer. Tumble home glass surfaces and large areas increase the greenhouse effect on passenger comfort, whether it is in Michigan or the Southwest desert. Today, the automotive industry is a world market and the products must meet the demand of the owner. Sun Test Engineering has run an a/c evaluation program to determine their level of performance on various a/c products in Phoenix. Arizona the last several years. In the summer of 1985, 17 vehicles were evaluated for customer usage test and the results of 7 vehicles are present in this paper. Additional test programs were conducted on the effect of film applied to the glazing surface. |
A Free-Flight Headform Impact Device for Evaluating the Energy- Absorption Characteristics of Vehicle Interiors | This paper reports on the design, development, and use of a test rig that enables the analysis of the aggressivity of vehicle interiors to the heads of occupants. The equipment comprises a pneumatically controlled free-flight headform device. It can be positioned inside the passenger compartment of any passenger car via any normal window or door aperture. The device fires a simulated headform prescribed in SAE J984 at speeds for 10 to 30 mph. The enormous degree of flexibility in positioning enables impacts to be conducted on almost any part of the vehicle interior. Currently, energy-absorbing characteristics of the interior of passenger cars are assessed using drop rigs or pendulums, which necessitate the dismantling of the vehicle body. This has implications for representativeness in terms of the validity of the stiffness characteristics of the section of the vehicle being tested. The results of testing standard specimens, using all three test devices, are presented and discussed. |
Materials Substitution in Automotive Interiors | Automotive interiors are evolving in the direction of increased: Luxury Passive occupant crash protection Acoustic and vibration isolation Electronic instrumentation Warranty life |
The Future of Random Vibration Screening and Testing in Automotive Engineering | Emphasizing stimulation (using random vibration and thermal shock), this paper first examines ESS (environmental stress screening), a relatively recent electronics production tool. Then it emphasizes simulation (of over-the-road random vibration), environmental laboratory testing during development. While different in their immediate objectives, the two subjects have a common goal: increasing the reliability of vehicles and their onboard electronic and other assemblies. |
An Overview of Automotive Interior Glass Light Scattering Film | Light Scattering Films (LSF) on automobile interior glass surfaces were studied on 35 vehicles. The principal chemical compounds that caused the LSF were identified along with the primary sources for these chemicals. The LSF composition and amount found on the windshields exhibited extreme variability. The causes of this variability are discussed. The health and safety of the occupants exposed to the extremely low levels of volatile airborne precursors of the LSF were also studied. Finally, the techniques are presented to: Measure the tendency of a material to contribute to the LSF. Characterize the composition of the LSF. Minimize the LSF in future automotive interiors. |
Simulation of Road Crash Facial Lacerations By Broken Windshields | The facial laceration test has been proposed as an addition to the dummy injury criteria of Federal Motor Vehicle Safety Standard 208. To better understand laceration conditions as they actually occur, three road crashes of increasing severity, all involving facial laceration by the broken (cracked) windshield and one involving partial ejection, have been simulated physically and analytically. The physical simulations used vehicle test bucks, the Hybrid III head with the chamois facial coverings of the facial laceration test, and a piston - constrained Head Impactor. Computer simulations of the three crashes were also carried out using the CALSPAN 3D “CVS” and the 2D “DRISIM” computer programs. The computer simulations provide insight into the effective mass of the head and body on windshield contact, and the forces, velocities, and accelerations involved. The computer simulations show how the impact velocity and effective mass of the head can be much higher than expected, due to body kinematics and loading of the head by the body during windshield contact. These simulations help explain accidents in which the windshield was broken by head contact in a 7.5 km/hr (5 mph) crash, and in which the head was partially ejected in a 21 km/hr (13 mph) crash. The physical simulations approximated the damage observed in the three accidents. In addition, the reduced laceration and potentially reduced ejection by the use of glass-plastic glazing was demonstrated. This paper presents the views of the authors, and not necessarily those of the National Highway Traffic Safety Administration. |
Interior Noise Control of the Saab 340 Aircraft | A comprehensive development program was performed on the Saab 340 aircraft, with the goal of reducing sound levels at the passenger seats in the plane of the propellers. The test program included in-flight sound measurements and operating deflection shape measurements on the fuselage structure, for various propeller speeds and synchrophase angles, and structural frequency response tests. The noise control approach developed was to reduce the low-order fuselage response with the addition of viscoelastic tuned dampers to the fuselage frames in the plane of the propellers. |
20 Questions About Acoustics in Industry | The potential contributions of acoustical technology to manufacturing companies pervade nearly all of its functions from marketing and product planning to design engineering and quality control. Despite this, however, companies generally feel uneasy when they embark on programs to use acoustics in their operations because the technology seems complicated and somehow harder to “get a handle on” than it is in other cases. But the issues of product sound, and the benefits of acoustics on a diagnostic tool are too important to ignore, so in this paper we discuss these issues in a “20 questions” format to help planners, engineers and managers as they proceed to implement acoustical technology in their organizations. |
Acoustical Measurements for Automotive Sound System Evaluation Using Time Delay Spectrometry | Over the last few years significant emphasis has been placed on the design of automotive sound systems having proper spectral and spatial performance. But often the frequency response of such a system is subjectively perceived as unbalanced. This paper investigates the direct sound field's frequency response in the car and the effect of the early reflections upon the total sound field. In-car acoustics and subjective test methods are discussed as well. |
A Wind-Tunnel Method for Evaluating the Aerodynamic Noise of Cars | In this paper a test method for measuring the car aerodynamic noise in the Fiat wind tunnel is reported. Through this method measurements of vehicle interior noise in the test section generated by air flow are performed. The separation between interior aerodynamic noise and background noise (fan noise, self generated noise in the tunnel, etc.) is performed by simulation of the last one with loudspeakers without air flow. The present method allows also to separate the shape noise contribution from aspiration wind noise and to localize the most critical acoustical areas into the car. By means of this method it is possible to optimize the car shapes and seals in order to improve the vehicle acoustical comfort. |
Automotive Convenience Products Trends and Prospects | The purpose of this paper is to describe the growth and the trends of automotive convenience products. These products contributed to make the driving experience more pleasurable. Electronics have contributed to this growth since the sixties, and its contribution and prospects will be the prime focus of this paper. With the continuing advance of electronic products in the consumer and industrial sectors, the consumer wants' and expectations are changing, especially with the “Baby Boom” generation. More new convenience features will be developed by the prudent use of electronics. The development of these future products require a thorough understanding of consumer wants and needs through market research, careful adaptation of the emerging technology to avoid gimmickry, and dedicated application of engineering know how to design package efficient, cost effective and reliable products. |
A New Dimension in Automotive Trim | Colamco has developed new technologies which have many advantages for automotive soft interior trim applications. The process is particularly suited to molded seat production but has proven to be flexible enough for use on any interior surface. The process combines standard polyether urethane foam with fabric or vinyl and any desired backing material to achieve highly styled parts both in 3-dimensional shaping and embossed designs. Products may also exhibit further characteristics such as softness, multi-densities, full breath-ability, and high durability, as well as noise reduction and acoustical insulation. In the report we will discuss Colamco Technology, materials requirements, automotive seat molding, inherent differences between the Colamco technology and other processes, and special applications of the technology. Emphasis will be on automotive molded seating. |
A Baseline Design for the Space Station Habitat | A baseline design has been selected for the Space Station Habitat (HAB) element. The HAB provides the primary living space to support man's permanent presence in space. The HAB element is designed to provide an environment that maximizes safety and human productivity. This paper outlines some of the current design features including the common core elements and the man-systems hardware. The HAB is arranged in three areas based on crew activity and acoustical considerations. The first area is the quiet zone, which contains the crew quarters. The second area is a buffer zone for noise suppression, where the stowage, medical facilities, and personal hygiene facilities are located. The third area is the active zone which contains the galley/wardroom, laundry and exercise facilities. Each of these three areas will be discussed together with the applicable requirements, the common utility elements, and the man-systems hardware furnishings. |
The Rolls-Royce Civil Engine Family - Today and into the Future | Rolls-Royce Civil Engine strategy calls for technology development for derivative engine programs and application to longer term new propulsion concepts. In the near future, further development of the turbofan for the next generation of derivative aircraft is planned. Reductions in fuel consumption, noise, weight, and cost will be achieved with engine cycles in the range currently in service and by refinements to component efficiency and application of advanced materials and manufacturing techniques. This derivative approach is likely to continue until the relationship between first and operating cost changes dramatically. As fuel prices rise, or the demand for more rapid travel develops, changes to the basic engine cycle will be necessary. For long range, high subsonic speed operation, substantial increases in turbofan bypass ratio will be needed to realize further fuel burn reductions. For intermediate ranges the propfan may have limited application, but economics will probably dictate retention of a more conventional powerplant for short range aircraft. |
Strength Problems of Low-Floor Urban Buses | The main characteristics of up-to-date urban buses are the low floor level, high capacity, and the many large-size doors. The longitudinal bending load bearing elements of the frame structures of thin window and door supports, suitable for today's popular line design pattern, are the sidewalls and beams without door openings. The main torsional load bearing element, on the other hand, is the master beam made up of the longitudinal beams by means of the floor cover and the lattice joint of the latter's lower flanges. Since the structural height of the longitudinal beams playing the critical role in load bearing is governed, at a certain minimum free height provided for, by the height of the floor level, reduction of the latter will have to be associated with that of their dimensions as well |
Improved Laminated Windshield with Reduced Laceration Properties | A new laminated automobile windshield called Triplex “Ten-Twenty,” fabricated from two thermally stressed glass plies of 2.3 mm soda-lime float glass laminated with a 0.76 mm HPR polyvinyl butyral interlayer, has been biomechanically evaluated by Triplex Safety Glass Co., Ltd., using a dropping headform and a skull impactor, and by Wayne State University, using a 50th percentile anthropomorphic dummy on the WHAM III sled test facility. The results of these evaluations at velocities up to 60 km/h are expressed in terms of Gadd index, head injury criterion, and various laceration scales including the new Triplex laceration index (TLI). Some details are also given of other properties of the windshield. The results of the evaluations indicate that the Ten-Twenty windshield offers a reduction of about two units on the TLI scale equivalent to one of the following: 1. A 99% reduction in the number of cuts when the length and depth of cuts remain unaltered. 2. A 90% reduction in the length of cuts when the number and depth of cuts remain unaltered. 3. A change in depth of cuts from one layer of skin simulation to another, but in particular a 78.5% reduction in the depth of cuts into the polyvinyl chloride base layer when the number and length of cuts remain unaltered. In practice, the length, number, and depth of cuts all change together so that one typical example taken from the test program of a two-unit reduction in TLI is: 1. A 62% reduction in the average depth of cuts into the polyvinyl chloride base. 2. A 27% reduction in the average length of cuts. 3. No increase in the total number of cuts. On the basis of these results, Ten-Twenty is a much safer laminated automobile windshield than those now commercially available due to decreased laceration to the occupants during a collision. |
European Legislative Requirements for Agricultural Tractors and Farm Machinery | This paper outlines the structure and interrelationships of the numerous European standards making organizations, with particular reference to agricultural machinery. Because many of the standards being developed by these organizations are becoming part of legislation in the various Common Market countries, their work is of great interest to the machinery manufacturers. Covered are the highway code-constructional requirements, safety constructional requirements, test codes, and engineering standards. The current status of requirements for lighting, tractor cabs (including structural tests, noise, and emissions), maximum speed limits, brakes, hitches, and safety in the various contries are discussed. |
The Design of a Cost-Effective Quiet Diesel Truck | This paper reports the results of a project whose aim was to develop a quiet truck in a cost-effective manner. In the paper a method of approach to identification of noise sources and diesel truck noise control is presented, along with a demonstration of noise control techniques and the results obtained. The final drive-by noise level, as measured by SAE J366a procedures, was 72 dB(A). The approach was to take a standard production truck and modify its exhaust system, fan, transmission, and cab enclosure. Although no modifications were made to the engine, a quieting kit consisting of dampening panels was fitted to it. |
The Environmental,Commercial and Regulatory Implications of SAE Recommended Practice J57a for Truck Tire Sound Levels | There can be no control over environmental pollution without methods for measuring how the environment is being affected by mankind. Consequently, when traffic noise was identified in 1964 by communities as an important form of pollution, it became necessary to measure the amounts of noise present and to assign relative importances to various sources in vehicular traffic. Truck tires were identified as being significant contributors and engineers from the tire and truck manufacturing industries acting under the auspices of the SAE set about to develop a test procedure that satisfied the immediate need - to initiate control over truck tire noise. This paper is a review of the outcome of that effort by one who participated in the earlier work on the testing standard. How well the method works, and how well it serves to meet the objectives now on the horizon are the preliminary topics of this discussion. The paper contains a discussion of the accumulated experience in testing tire noise and the current indications for a meaningful test procedure. |
Photovoltaic Glazing for Automotive Applications | A computer simulation of an automobile has been prepared which enables the spectral characteristics of the glass windows, semitransparent photovoltaic sunroofs, and special solar control coatings and films to be incorporated into the thermal analysis. This paper presents the resultant interior temperatures for three vehicle configurations when subjected to various ventilation flow rates, convection conditions, and solar control coatings. |
A Comprehensive Programme for Hearing Conservation and Noise Control | Emphasis is placed on noise control at source in the hearing conservation programmes in the U.K. factories of Lucas companies, especially when new plant is ordered. This paper briefly describes the overall plan and Company standards with five case studies to illustrate how they work in practice. It concludes with a summary of the key steps in the Company strategy. |
A Unique Approach to Mobile CB | A new 40-channel CB Radio System has been developed by a major automotive manufacturer as a regular production option for a number of its 1978 cars and trucks. To maximize theft resistance, the system uses a remote chassis, detachable microphone, and a tri-band antenna. The factory-installed CB features a uniquely styled power microphone, digital channel display, automatic scan, switchable noise blanker, memory for emergency channel 9, automatic noise limiter, and extensive vehicle noise suppression. Vehicle speaker(s) are time-shared with the entertainment system. This state-of-the-art system is presented here in terms of component functions, design development, manufacture, and test equipment and procedures. |
Quiet Tires-An Overview | Vehicle and tire manufacturers are currently working to produce quiet commercial vehicles and tires. While much time has been spent by both government and industry to gather data to cut vehicle noise, it seems that industry and government now wish to interpret this data and make use of it in a short period of time. But this cannot be done without consideration of cost. We must consider the initial investment of new tires, the labor involved and importantly the national availability of these products as replacements are needed. Only with the full cooperation of government, manufacturers, and the transportation industry can this be accomplished. |
S-65-200 Commercial Compound Aircraft Design for Maintenance | In the design of the S-65-200 Commercial Compound Aircraft - a 230 knot, 86 passenger transport - maximum consideration was given to meeting a high dispatch reliability goal and to ease of performing maintenance. This paper describes how maintenance and reliability of this compound helicopter is enhanced by use of new and improved technology. Use of built-in test equipment reduces electronic component maintenance by approximately 43%. An airborne integrated data system reduces line level maintenance by approximately 16% and provides trend information for detection of incipient malfunctions. A newly developed rotor head bifilar vibration absorber reduced aircraft vibration levels, thereby reducing airframe and structure maintenance by almost 15%. A modularized engine allows for minimum disassembly at intermediate levels of maintenance. New and high grade materials, such as composites and vacuum-melt steels, improve life characteristics of structure and dynamic components. The ability to inspect subsystems is increased, and all components are readily removable. Almost 95% of all maintenance actions are performed from outside the aircraft. The cumulative result of these features of the S-65-200 Commercial Compound Aircraft is a predicted 0.98 dispatch reliability. Direct maintenance is estimated at 9.3 maintenance manhours per flight hour for all levels of aircraft maintenance. |
Development and Analysis of Door Side-Impact Reinforcements | A door side-impact reinforcement beam has been developed that allows efficient use of material in resisting side crush loads. The beam section can be roll formed, thus permitting further economies in fabrication. Analytical techniques have been developed that evaluate and handle bending, buckling, and crippling in beam design. This paper covers the development that led up to these results and includes a detailed description of how to apply the analytical methods. |
Importance of Acoustical Leaks in Passenger Car Bodies | In its treatment of acoustical leaks in passenger car bodies, this paper considers the general principle of noise control in a passenger compartment, the concept of acoustical leaks, examples of such leaks, and design guidelines for acoustical isolation. The paper states that the basic problems can actually be designed into vehicles through lack of understanding of acoustical principle, and various examples are given in illustration. Remedies for some of these deficiences are also proposed. Finally, design principles formulated to eliminate acoustic leaks are presented. |
System Engineering - A Window System | Many of the formal system engineering procedures and techniques developed in the aerospace industry have convenient informal application to the analysis, evaluation, and qualification of new automotive design. This paper describes such “systemization” from a product engineering viewpoint in the development of a hardtop window project. The project is traced through its several design and development stages; and the advantages of the system engineering approach, as well as some of the problems encountered, are explored. The paper concludes with a discussion of additional controls that would have been required to yield the full information recording/retrieval capability demanded for complete system integration on larger projects. THE COMPLEXITY OF the present-day automobile is as evident in its door window systems as it is beneath the hood. Current usage of curved glass, repeatably positionable at superhighway speeds in a frameless or hardtop application, has posed new challenges for the designer. Additional emphasis on sealing capability, reduced operator effort, and low noise levels has compounded the design challenge. The designer has met these challenges by producing systems much more sophisticated than those in earlier cars. Optional hardware configurations that can be added or deleted from the system and partial modification of existing systems with during-model-run effectivity points are routine. Also, the cost of both materials and the labor associated with assembly, adjustment, and service are receiving additional emphasis today. All of these factors combine to make the product engineer's task in verification testing of window systems more difficult, and at the same time more important than it was previously. |
Consumer Acceptance of the Volvo Passive Belt System | Consumers' acceptance of and attitude toward a passive three-point belt system have been studied and evaluated in a personal interview investigation of 325 people. These participants were provided with the opportunity to try out the belt system in two demonstration cars-2-door and 4-door sedans. The method of selecting the respondents complied very well with the requirements of public representation. The results of the inquiry are presented in the full survey as related to driver, passenger, age, sex, etc. The main question in the study-the convenience when entering or leaving the demonstration car-was very positively judged. The most frequent opinion on a 7-point evaluation scale was as high as 7 (most positive); the average value of 6.2-5.9 was given for wide- and half-open doors, respectively. |
An Update on Noise Control at International Harvester | International Harvester has testified to the Environmental Protection Agency about present noise levels and has stated what it considers to be reasonable goals. Noise control work is progressing, especially in the area of environmental noise on lawn and garden equipment and operator noise on larger tractors. The engineering community must take every opportunity to present the case for cost-benefit considerations in noise control. |
Comparison of Three Types of Front Body Construction of Sub-Compact Cars | Three different types of front suspension and the corresponding body construction configurations were selected for comparison among unitary constructed sub-compact cars with a weight range between 2,500 lb and 3,000 lb and which are being manufactured by Toyota. These were compared and evaluated in terms of weight, productivity, noise and vibration characteristics, and crashworthiness. The pros and cons of each type were analyzed and the results of this analysis are presented in this paper. From these results, it has been concluded that when only the front body is considered, these three types of front body design are preferable in the following order. 1. McPherson type. 2. Double wishbone type with upper and lower arms installed on the fender apron. 3. Double wishbone type with upper and lower arms mounted on the suspension member. |
180 Cu Yd Stripping Shovel | Because of the size and weight of the various components going into the machine, new approaches were used to solve the practical limitations of manufacturing facilities, shipping clearances, and erection procedures. Although the general appearance of the machine is similar to previous units, there are a number of new design features incorporated in the unit. This paper will be limited to the major design considerations as follows: adaption to stripping two seams of coal simultaneously; dipper with two doors; computerized hydraulic steering maintaining Ackerman correction; double end drive crawlers and belt tensioning; and electrical innovations. |
Noise Abatement of Vibratory Feeders | Three principal noise-generating mechanisms were identified in the vibratory feeder as structural vibrations, interaction between the conveyed parts and the track surface and radiation from the bowl cavity. Treatment of the track surface based on theoretical analysis of the vibration-stimulated conveyance, structural damping treatment of the bowl and “see through, load through, reach through” acoustical screen have been developed. These treatments lead to 20–25 dBA reduction of the sound pressure level accompanied by substantial reduction of part delivery time. |
Past, Present and Future of Elastomeric Body Sealers in Automotive Application | Automotive body sealing has progressed from the time when the internal combustion engine replaced the horse on the buggy, which had no windshield, windows or doors, to the present time when every effort is made to make the passengers as comfortable as possible by isolating them from heat, cold, wind, water and noise. This pursuit of comfort has not only been made possible by but has also created the need for new developments in designs, materials, manufacturing procedures and tooling. |
Metal Stamping Presses Noise Investigation and Abatement | Noise generating mechanisms connected with steel-blanking operation has been identified and their engineering treatments developed and tested. Use of rubber-metal laminates proved to be successful for cushioning impacts in kinematic pairs and joints. Use of plastic for the stripper plate construction was recommended. The “die stiffener” concept was developed to reduce main noise peak associated with punch breakthrough. Screening of the die cavity by a transparent curtain of overlapping PVC strips was shown to be effective. A pulse load simulator with adjustable load rate and amplitude has been developed to facilitate testing of presses. |
Optimum Subsonic, High–Angle–of–Attack Nacelles | Many proposed advanced aircraft - but especially tilt-nacelle, subsonic-cruise, V/STOL aircraft - require nacelles that operate over a wide range of aerodynamic conditions. The optimum design of such nacelles and their inlets is described, including how the inlet low-speed design conditions are selected, the conditions for which the various regions of the inlet are designed, and appropriate criteria of merit. For low-speed operation the optimum internal surface velocity distributions and skin friction distributions are described for three categories of inlets: those without boundary-layer control (BLC), those with BLC, and those with blow-in door slots and retractable slats. Experimental results are presented that show the performance of the various types of inlets. At cruise speed the effect of factors that reduce the nacelle external surface area and the local skin friction is illustrated. These factors are cruise Mach number, inlet throat size, fan-face Mach number, and nacelle contour. The interrelation of these cruise-speed factors with the design requirements for good low-speed performance is discussed. Finally an inlet design without BLC and an optimized inlet design with slots and slats are compared to illustrate the possible reductions in nacelle size. |
Energy Conservation Aircraft Noise, and the Bottom Line | The established distribution system is in the process of being restructured to combat the effects of high cost energy, inflation and environmental restrictions. As a part of this system, the air freight industry, also, must re-examine its options in equipment, energy reduction, financial risk and services offered. In the area of investment and energy reduction a cost effective solution is already available. That is, equip a portion of the existing cargo fleet with new technology, quiet, fuel efficient engines. Ten airlines have stepped up to this solution and are re-engining their fleets of DC8 aircraft with CFM56 engine. |
A General Aviation Operator Views His Equipment | Each new model change usually brings improvements over earlier models. From the point of view of increasing window area and designing more pleasing appointments, there have been significant advances. With regard to engine reliability and time between overhauls, significant advances have also been made. Solutions to some of the other problems, however, have made little gains. Examples are pilot sitting position and ease of seeing outside the cockpit area; noise level for effective verbal communications between instructor and student; and shoulder space for instructor and student in trainers. An area where major strides are yet to be made is in panel, cockpit, instrument, and control layout and function. A continuing concern expressed by pilots is the transition time from one aircraft to another or the problems of regularly operating in two or more aircraft. This suggests that there is a need to provide more commonality between airplane layouts. Since the hourly maintenance labor costs are increasing, the original design should consider labor-saving methods during routine inspections such as accessible location of battery. Performance data and aircraft systems descriptions should be more uniform between manufacturers. |
Airport Noise, Sonic Booms, and Public Health | Different adverse effects of noise are treated in the context of defining public health problems posed by exposure to sonic booms and to operational aircraft noise around airports. These aircraft sounds can affect states of social and mental well-being through masking speech communication or other desired sounds, disrupting behavior and subjective feelings, and interfering with needs for privacy, rest, and sleep. Such adverse effects fall short of what may be called mental disorders, but the long-term cumulative impact of these noise disturbances remains to be fully evaluated from the standpoint of mental as well as physical health. There may, however, be some potential risk of hearing loss caused by the maximum current aircraft noise exposures in neighborhoods bordering airports. Evidence for other physical ailments connected with exposures to aircraft sounds intruding in airport communities is suggestive at present and requires more medical verification. The most pressing research needs are for retrospective and prospective studies of the physical and mental health status of communities subjected to different amounts of aircraft noise and sonic booms. |
Sound Attenuation After the Fact | The noise levels of earthmoving equipment, in the operator's cab and outside the machine, are discussed. Ways and means of lowering the dB ratings for increased operator and by-stander comfort are taken into account. Suggestions are made for ways of mounting the cab itself and lessening vibratory reactions from the engine, including rubber engine and cab mounts, plus acoustical material for reducing inside the cab noise. |
The Economic Necessity of Viable Door to Door Air Cargo Service | Air freight is and will continue to be a small shipment business. The rapid increase in the amount of freight carried has induced a state approaching chaos on the ground. The result is delay, losses, and damage to shipments. The air cargo industry must now develop a sophisticated door to door capability offering improved service and lower costs to the user. Satellite air freight depots, with perhaps several airlines in a single building, must be developed in major commercial areas. Door to door container usage, at present faltering, should be encouraged. A new rating system, with door to door prices that taper with distance, should be devised. |
A Passive Safety Belt System | The geometry and behavior of several front-seat passive belt configurations have been studied and evaluated. General design criteria are discussed. The preferred solution is a three-point belt with two ends attached to the door. The belt straps automatically, and for comfortable exit, the occupant may make a slight manual operation. Crash tests indicate that the belt performs approximately as a standard three-point belt. Door strength, retractor strength, strap strength and tension, seat influence, etc., have been tested. Curves are given for recorded and computed data, including old and new severity index. |
One-Wire Automotive Electrical Systems | A single-wire vehicle electrical control system is applied to the various vehicle electrical functions. The resultant three-wire system (signal, power, ground) reduces wire bulk in the floor, door, instrument panel, and engine compartment of the vehicle. Increased control switch and component complexity, due to the additional solid-state components required, may affect overall reliability. Improved power bus and signal bus protection must be added to the control system. Failure of the entire single-wire control system, due to accidental grounds or opens, limits application to certain noncritical vehicle electrical systems. |
Summerization of Construction Equipment | This paper discusses some of the problems encountered in “summerizing” or air conditioning a cab used on construction equipment. The environmental conditions of high temperature and high relative humidity combined with severe dust shock and vibration conditions affect the design of components. Components discussed are compressors, condensers, evaporator coils, filters, air ducts, air diffusers and heaters. Installation for ease of maintenance and replacement is emphasized. |
Evaluation of Aircraft Internal Noise | From the standpoint of marketing as well as safety, control of aircraft interior noise is of considerable interest to the manufacturers of business aircraft. The interior acoustics engineer in the industry, having no fund of accumulated experience or research to draw from in the industry itself, has to piece together a working design procedure from a knowledge of boundary-layer theory, jet noise, random vibrations, and architectural acoustics to meet an acceptable cabin noise criterion for the small aircraft. In this paper, methods are outlined to calculate the cabin noise levels due to the three main noise sources-the boundary-layer pressure fluctuations, jet exhaust, and internal equipment. Formulas for quick estimation of overall noise levels due to these sources as well as methods to obtain octave band levels are given. The paper also discusses manufacture or service-related noises and methods for identifying their sources. |
Window System Design Using Computer Analysis | Soon after the styling door surface, glass drop, and belt height are determined, the placement of window system components is critical in effecting a smooth operating window system with low effort. For single arm - single post window systems, a computer analysis technique has been developed to position the post and regulator in the most optimum location. The computer program used displays results through the use of computer graphics. This graphic output allows instantaneous evaluation of how variations in geometry effect the window system operation. |
A Consideration of Vehicle's Door Shutting Performance | Many papers have mentioned, in passing, a phenomena that is known as “airtightness”, which is one factor that hinders automobile doors from closing. It also causes the eardrums of any passengers in the vehicle to be temporarily pressurized when the door is closed. However, few documents have considered this phenomena in detail. In this paper, we investigate the magnitude of “airtightness” as it affects ear pressure and examine its relationship to such factors as the volume of the passenger compartment, door's opening area and its inertial moment. Finally, we utilized estimation methods to predict its influence on the force required to close the door and the amount of the resultant air draft. |
Development of Door Guard Beams Utilizing Ultra High Strength Steel | Door guard beams have been developed through the utilization of ultra high strength steel (tensile strength>100 kg/mm2). At first, the sheet metal gauge was reduced in proportion to the strength of the ultra high strength without changing the shape of the beam section. This caused beam buckling and did not meet guard beam specifications. Analyzing this phenomena in accordance with the buckling theory of thin plates, a design criteria that makes effective use of the advantages of ultra high strength was developed. As a result, our newly designed small vehicle door guard beams are 20% lighter and 26% thinner than conventional ones. This makes it possible to reduce door thickness while increasing interior volume. |
Vibration Analysis by Double Pulsed Laser Holography | The use of a giant pulse laser with 30 ns double pulses makes it possible to holograph different phases of an object vibration within time intervalls from 100 μs to 1 ms onto the same plate. The vibration phases into which the first and second laser pulse are fired can be exactly preselected by means of an electronic trigger system. The simultaneous reconstruction of the holograms taken by the first and the second laser pulse generates on the object surface a system of interference fringes which are loci of equal displacement. Adjoining fringes correspond to displacement differences of half a wavelength of the laser's light. In this way, it is possible, for instance, to visualize the vibration pattern of car bodies and drive units excited by the running engine. The method of measurement and a hologram camera especially constructed for making double pulsed holograms of automobiles are described. Several examples of application are quoted in order to illustrate this technique. |
Development of an Indoor Noise Test Procedure for Trucks | An alternate, indoor, noise test procedure for truck exterior noise is being developed in order to overcome the weather problems associated with the presently employed outdoor test method. The feasibility of a reverberation room measurement of sound power level has been demonstrated through a series of comparative indoor and outdoor measurements for several vehicles. An indoor test procedure has been broadly defined and an experimental effort is continuing to complete its development and to demonstrate its equivalence to the outdoor passby test. |
Aircraft Noise Control Practices Related to Ground Transport Vehicles | Aircraft noise control practices which may have application to ground vehicles are presented. Noise sources, design criteria, prediction methods and test facilities are described. Recent application of aircraft noise control methods in the use of sound insulation, structural damping, air conditioning and engine noise are discussed. The overall technical approach (design process) to solving airplane noise problems is emphasized. |
Materials for Noise Control | The purpose of this paper is to present a basic overview of the technology and materials available for controlling airborne noise and structural vibration. The paper will be oriented to the truck industry. Materials and applications will be presented with this bias. The paper will cover technology of absorption, reflection and vibration damping. Material properties, availability and practical considerations to selection will be presented. Typical applications for materials in the truck market will be briefly highlighted. |
An Example of Noise Control Treatment for Construction Machinery Cab Interiors | The effect of noise on the operator has become of increasing concern to manufacturers of construction machinery in recent years. Although the noise generated by heavy duty construction equipment is much greater when compared to other types of machines such as the passenger car, the problems are similar. Many of the lessons learned in reducing interior noise within the automobile can be used to reduce noise within the operator's cab of construction machinery. This paper represents the results of a joint effort between Fiat-Allis Construction Machinery, Inc., and Globe Industries, Inc. to apply these lessons to reduce the noise within the cab of a medium sized crawler tractor. |
Durability of Rubber Modified SMC | A carboxylated butadiene-styrene elastomer has been developed as a low profile modifier for polyester resins used in sheet molding compounds. The elastomeric modifier will provide Class A surfaces with low long-term wavi-ness, energy absorbing characteristics and zero shrinkage. Especially outstanding results are obtained when molding large, thin, flat panels such as roof, door, hood and tailgate panels from rubber modified SMC. Surface appearance properties are subjective, but properties such as radial bend, tension testing, high impact and reverse impact tests are shown to demonstrate the energy absorbing and toughening characteristics imparted by the modifier. |
A Bus for Denver’s Mall | A unique shuttle bus is being constructed by Minicars, Inc., and Walter Vetter Karosserie-werk for Denver’s Transitway/Mall. The bus is designed for frequent stop, low speed service in a downtown pedestrian environment. It features a very low floor and multiple wide doors for rapid passenger boarding and deboarding. Two versions will be supplied for comparative evalation, a low noise diesel configuration and a battery-electric configuration. Either version can subsequently be converted to the alternative propulsion system. |
State-of-the-Art-Ergonomics and Motor Vehicle Safety | The use of ergonomics in the design of vehicular equipment is presented. It is proposed that the wider use of the principles and methods of this discipline might aid in the more effective integration of the driver and his equipment. It has been shown that the effectiveness of any man-machine system depends upon the integration of the biological characteristics of the operator with the mechanical design of the equipment and working areas. The initial phase of a program in ergonomics should always consist of an advance analysis of the equipment, including a survey of the nature of the task, the work surroundings, the location of controls and instruments, and the way the operator performs his duties. In highway safety the application of human engineering principles has been shown to be of great importance in the design of windshields, rear view mirrors, and vehicle lighting, and other visual aids to the drivers. The field of crash injury research is proving to be especially important in understanding the parts of the vehicle most likely to give rise to injury. Current research is tending to give more precise measurements not only in regard to the forces involved, but also to the thresholds and patterns of injury. The various research programs in the field of ergonomics as related to highway safety in various parts of the world have greatly increased in recent years. |
Reducing Construction Equipment Cooling System Noise to Meet the French Noise Requirement | A major noise source on construction equipment is the cooling system when tested according to the French Noise Test Procedure. This paper describes the procedure and methods used to reduce economically the Case 580B CK loader-backhoe cooling system noise to 75 dB(A), well below the French limit of 80 dB(A) for the whole vehicle, and remain within the desired physical and performance constraints. This was accomplished primarily by reducing fan speed and using a larger capacity radiator to maintain adequate cooling. |
Experimental Studies of the Space Shuttle Payload Acoustic Environment | Two series of experiments were conducted to reduce the uncertainties concerning the Space Shuttle payload bay acoustic environment. Tests using a one-fifth scale model showed large changes in level below 125 Hz with the introduction of typical payloads. The changes were associated with particular acoustic modal behavior and were sensitive to the type of acoustic excitation. Another series of experiments evaluated the noise reduction of the first orbiter vehicle (OV-101). The results showed consistently greater noise reduction for grazing excitation than for diffuse excitation. The results were extrapolated to OV-102 using mass law relations and acceleration measurements. |
Light Vehicle Frontal Impact Protection | This paper addresses the protection of occupants in light vehicles. It presents data and techniques for identifying and measuring potential crashworthiness improvements that would mitigate injuries to occupants striking frontal interior components such as the steering wheel, instrument panel and windshield. Both restrained and unrestrained occupants can be injured by frontal interior components in crashes. The focus of this paper is on the unrestrained occupant. However, performance criteria and associated countermeasures will have to be developed considering the differences in the mechanisms of injury to both the restrained and unrestrained occupants. Work on the restrained occupant and the similarities and differences between both conditions remains to be considered. The paper presents information on the magnitude and types of injuries received from frontal interior components and on how the performance of these components and the vehicle structure affect the resultant injuries. |
GMC Fiberglass Truck Door | A new fiberglass door was designed to replace steel doors on GMC heavy duty trucks as a quality improvement while reducing cost and weight. A feasibility study led to the selection of SMC for the door material. The new design incorporated unique design features and innovative materials applications. Finite element analysis was used to determine optimum material distribution for reducing stress and weight and for increasing stiffness. A test program was conducted which verified the design criteria and objectives were met. |
A Subjective Assessment of Truck Ride Quality | A subjective assessment of ride quality was undertaken in order to estimate the relationships among 22 factors that affect concepts of ride quality and to assess the interaction of these factors with 7 ride quality issues. Nine line-haul drivers drove and rated each of 16 tractor-trailer vehicles. The factors, driver vibration, ease of steering, and interior cab noise determined overall impressions of ride quality. Of the issues, front axle load, tractor configuration, tractor rear suspension, trailer suspension, trailer load, wheel base length, and newer and older cab designs, the latter evoked the clearest differentiation of ride quality between paired vehicles. |
Reduction of Traffic Noise Impacts Via Path Controls | Path control measures to reduce traffic noise impacts include roadway alignment, site planning, noise barriers, and building insulation. Roadway alignment and site planning are most effective when included during the project planning stages. For existing noise problems, roadside noise barriers are effective, providing reductions of up to 15 dB(A). Some sites require building insulation to reduce traffic noise impacts. Three levels of modifications are considered: (1) sealing leaks, (2) modification of small structure elements, and (3) wall panel modifications. |
Side Impact Modelling Using Lumped Mass and CAL-3D CVS Simulations | Experimental research to improve protection levels offered to automobile occupants in lateral collisions has focused on the study of responses of the 50th percentile male as a result of the availability of the Side Impact Dummy of that size. The question of the suitability of protective measures developed for the 50th percentile male for the other occupant sizes is of concern. Hence, a major objective of this study was to analytically evaluate injury potential of a broad range of occupant sizes in lateral collisions in combination with various types of padding. Two computer models were used in the study. The first was a one-dimensional lumped mass model. The CAL-3D crash victim simulation was also configured to represent an occupant in a lateral collision with intruding door motion. Results of the study indicate that padding on the interior of the door surface is beneficial to all occupant sizes. |
Interior Noise Reduction in a Recreational Van | A study was made to determine the effect of combinations of acoustic treatments on the interior noise levels in a 3/4 ton van. The effect of barriers, absorbers and vibration dampers in various combinations on the dBA levels are given for both idle and highway operating conditions. A noise reduction of up to 10 dBA was obtained for certain barrier and absorber combinations. |
APPLICATION OF THE FINITE ELEMENT METHOD TO THE DOOR INTRUSION AND ROOF CRUSH ANALYSIS OF A PASSENGER CAR | In order to satisfy the various international safety standards which currently exist, it is necessary that nearly all new vehicles be subject to a number of destructive tests before being made available to the public on the open market. Development programmes involving a series of such tests are very expensive and there is a growing need that reliable and economical design/analysis methods be made available. This paper attempts to present such a method. Using a relatively simple finite element computer program which has been adapted to the particular needs of the motor industry, the analysis of a new prestige limousine is described. A background to the analytical method is presented, but the emphasis of the paper is on the engineering aspects of using the method. Reference is made to practical design considerations in several instances. The results of calculations predicting the performance of the structure when subject to FMVSS 214 and 216 are presented. |
External Surface Noise Radiation Characteristics of Truck Diesel Engines - Their Far-Field Signatures and Factors Controlling Abatement | The engine is an important source of diesel powered vehicle noise, and becomes dominant after proper treatment of exhaust and cooling system noise at vehicle speeds below fifty miles per hour. This paper presents the results of a comprehensive study dealing with surface noise radiation characteristics and the ranking of sources on three truck diesel engines. A special acoustic facility constructed to emphasize the acquisition of diesel engine noise data is describad. Information is presented on measurement methodology and its viability for quantification of engine noise, directivity, and radiation patterns from engine surfaces. Acoustic measurements, conducted over a range of engine loads and speeds, include spectral analysis of the sound pressure field derived from a thirtytwo microphone spherical array. Various noise identification techniques are explored under comparative testing to ascertain potential candidates for quantification and ranking of engine external surface radiation. For the engines studied, the sound power output varies, depending on design; the loudest being the naturally aspirated; and the quietest being of prechamber design. This range varies between 8 and 10 dB (A) at maximum throttle and is speed dependent. Turbocharged engines exhibit a marked change in sound power output under increased load conditions. This is most pronounced at lower engine speeds. The sound pressure field of two in-line turbocharged four-stroke diesel engines contained a high degree of asymmetry whereas the sound pressure field of a two stroke vee configuration engine appeared representative of a finite monopole acoustic radiating source. Major external engine surface acoustic radiators, common to all engines tested, included engine front, block sides, and valve covers. Other major external sources were after-coolers and exhaust manifolds for specific engine designs. Oil pan noise, although a lesser contributor to overall engine noise, depends on factors which include the design, material and construction. Finally, comparisons are made of noise data acquired for the acoustic facility and data acquired for the same engine installed in a typical highway truck chassis located out of doors. |
Noise Reduction of a U.S. Army 5-Ton Truck | Research is demonstrating that it is possible to significantly reduce the in-cab noise levels of the Army's current truck fleet, with accompanying exterior noise reduction. Results are applicable to future Army trucks as well and are reported on a program utilizing a 5-Ton Army Truck. This type of truck was found generally to exceed the applicable limits established in the new MIL-STD 1474, “Noise Limits for Army Material.” The program identified major noise sources and important paths for sound to enter the cab and resulted in the selection of optimum sound absorption, sound barrier and vibration damping materials. The effect of a prototype exhaust system and its placement relative to the cab and the importance and optional means of controlling cooling fan and engine noise were also investigated. |
The Evolution of Sound Testing at Kohler Co. | The purpose of this paper is to discuss the development of Kohler Company's Small-Engine Noise Test Program. Particular emphasis will be placed on noise instrumentation and analysis techniques. The paper will not dwell on the specifics of each noise study technique, but will be an overview, describing the evolution of Kohler's Noise Test Program in general. |
Development of Lightweight Door Intrusion Beams Utilizing an Ultra High Strength Steel | Door intrusion beams have been fabricated from an ultra high strength steel resulting in an efficient side impact protection system. Despite the ultra high strength (yield strength∼150 ksi) the steel may be roll formed into beams from thin gauge material (0.035 in) resulting in significant vehicle weight savings while still meeting all federal specifications. This paper covers the development of this door intrusion beam system and includes detailed descriptions of beam design, beam testing and steel properties. |
Hailstone Response of Body Panels - Real and Simulated | The dent resistance of aluminum and steel autobody panels has been studied under controlled laboratory conditions and by field observations and measurements of actual hailstone damage. Analysis of the results shows that very nearly the same response occurred in the lighter weight aluminum components as occurred in the steel panels. The autobody components were all 1977 model year production panels. Laboratory testing included four steel and four aluminum hoods, both painted and unpainted. The hailstone damaged components included a steel hood, aluminum doors and an aluminum fender. The aluminum and steel panels were damaged in the same hailstorm during May 1977. The analysis of denting resistance presented in this paper is based on insight and experience gained from a four-year cooperative program of Reynolds Research and several automobile companies. The results given here supplement previously published laboratory data and confirm the conclusion that lighter weight aluminum autobody panels can be designed to give at least comparable, if not better, dent resistance than conventionally used steel panels, and at a weight savings of 50 percent. |
New Designs Through Vibration Welding | A new plastics assembly technique has been developed which offers new opportunities in product design and assembly as well as new solutions to existing problems. This method, based on friction welding, overcomes many limitations of conventional welding processes such as part size, shape, material and speed of operation. It produced strong, pressure tight joints. |
Evaluation of Cooling System Design for a Portable Air Compressor Designed to Meet EPA Noise Requirements | A cooling system design for a gasoline engine powered portable air compressor designed to meet EPA noise standards is evaluated. This paper covers the development that took place in order to devise an adequate cooling system for a silenced compressor with noise reduced by shrouding of the machine with a sound attenuating housing. The successful cooling system consisted of resolving maximum engine coolant temperature and maximum compressor discharge temperature while maintaining a compressor noise level of 76 dBA at 7 m. The cooling system design procedure involved is outlined. Noise evaluation at Sullair Corporation, and cooling system testing at McCord Corporation are reported. |
Highlights of UMTA's Rail Program | This paper highlights the role rail research programs of the Urban Mass Transportation Administration (UMTA). Included are descriptions of several recently developed commuter transit cars-the state-of-the-Art Car, The Advanced Concept Train and dual-powered, gas turbine/electric cars. Also discussed are efforts by UMTA in developing test facilities for urban rail vehieles and in furthering research in tunneling technology and noise abatement. |
Designing Body Panels for Corrosion Prevention | To aid in avoiding the corrosive elements of the environment, the designer of sheet metal body panels should consider principles which provide optimal drainage and access for the application of protective coatings. Major vehicle body components are considered individually or in closely related pairs such as door inner and outer panels. The general guidelines for preferred construction of drain holes, shingling, shielding and access for material application are outlined for each major component. |
A Method for Assessing Turbine Engine Run-Up Noise Impact on Airport Neighbors | A methodology for assessing ground run-up noise exposure/impact resulting from turbine engine performance testing on outdoor facilities was developed. The overall methodology consists of three calculation procedures using dBA levels (measured or estimated) to predict the Day-Night Level (LDN) at any location across existing terrain. The methodology provides the analysis capability required to 1) study noise suppressor requirements in order to minimize costs, 2) locate run-up and test-cell pads, and 3) study the impact of run-up operations changes. It also provides a potential capability for assessing noise exposure from 1) takeoff power check run-ups, or 2) other (non-turbine) static noise sources. |
Experimental Approach to Reduction Technique for Engine Noise in Passenger Compartment | This paper deals with high frequency noise in the passenger compartment which are caused by transmitted engine noise. For the purpose of noise reduction, several evaluation methods are developed. For the evaluation of a body transmission loss, a combination of a reverberant room and an anechoic room is used. The noise absorption of the compartment is evaluated under the concept of the saturated sound pressure level. And sufficient standard samples are measured to support the noise reduction development. |
Noise Control on a Heavy-Duty Mobile Crane | The intent of this paper is to illustrate how simple testing techniques and application of elementary noise concepts helped attenuate the noise in the operator cabs of a heavy-duty mobile crane to within the 8 hour/90 dBA limit established by the Occupational Health and Safety Act of 1970. |
A Modern Technology, Open-Ocean Seaplane Design | Modern technology has been applied to derivation of a viable open-ocean seaplane design capable of operation from, and sea sitting in, sea state 5. Beginning with a delineation of traditional seaplane limitations and philosophically unencumbered by orthodoxy, the design features a blended catamaran-fuselage hull, hydrofoil, high wing, twin boom, and Vee tail with top-mounted engines. Weighing 1.25 million pounds including weapons and avionics suite, the design has been applied to a Sea Control mission. Consideration has been given to concepts for inhibition of motion sickness. |
Flight Displays for the Next Generation Aircraft | The influence of the increasing complexity of the commercial transport operating environment is cited as the reason for applying advanced display technology to new aircraft design. Principal factors are the fuel crisis, sensitivity of the environmental noise, and the need for increased traffic capacity. Industry-wide development programs for fully configured flight decks, as well as specific subsystems, are reviewed. |
Reduction of JT8D Powered Aircraft Noise By Engine Refanning | The purpose of the Refan Program is to establish the technical feasibility of substantially reducing the noise levels of existing JT8D powered aircraft. This would be accomplished by retrofitting the existing fleet with quieter refan engines and new acoustically treated nacelles. No major technical problems exist that preclude the development and installation of refanned engines on aircraft currently powered by the JT8D engine. The refan concept is technically feasible and provides calculated noise reductions of from 7 to 8 EPNdB for the B727-200 aircraft and from 10 to 12 EPNdB for the DC-9-32 aircraft at the FAR Part 36 measuring stations. These noise levels are lower than both the FAR Part 36 noise standards and the noise levels of the wide-body DC-10-10. Corresponding reductions in the 90 EPNdB footprint area are estimated to vary from about 70% for the DC-9 to about 80% for the B727. The refanned aircraft should perform typical range/payload missions with a negligible effect on block fuel. Production retrofit kits could be available in 1976 for the DC-9 at a unit cost of about $1.0 million and in 1977 for the B727 at a unit cost of $1.7 million. |
A Noise Control Study of Certain Diesel-Powered Strip Mine Vehicles | This paper describes the work performed in three distinct noise studies on typical diesel-powered strip mining equipment and discusses their results. Mufflers lowered diesel exhaust noise exposure for adjacent workers and the community at large, but had little effect on the noise level at the operator's position. Properly designed and installed noise control kits can be an effective method of reducing the operator's exposure to an acceptable level, and can simultaneously dampen vibration inside the cab. |
An Investigation of the Noise and Overpressure Generated by the Safety Air Cushion | The results of an experimental study of air cushion noise and overpressure are presented, and methods to reduce these effects are investigated. Free-field studies of inflator noise are made in an open anechoic room, and various silencing devices are tested. Studies are also made of the combined inflator noise and overpressure in a closed passenger compartment. Tests are made for different window openings in the compartment. Results are presented for a new experimental air cushion that draws in air from the passenger compartment as it inflates. Some of the implications of the data with regard to risk criteria for damage to human hearing are discussed. |
Experimental and Theoretical Study of the Rolling Noise in a Passenger Car | This paper presents an analysis of low frequency noise production by experimental measurements and mathematical model calculations. It shows vibration coupling between train, body and cavity modes and it points out different possibilities to reduce noise in the passenger compartment. |
A Method of Sound-Field Simulation for Automobile Passenger Compartments | By estimating the sound field characteristics of an automotive cabin at a period prior to the actual manufacture of a car using available information on interior size, shape and acoustic materials, it is possible to realize a car audio system of high quality through appropriate placement of loundspeakers and determination of best electrical compensation networks, among others. We have established a computer-aided method based on the sound ray-tracing method and digital signal processing techniques usually applied to the analysis of large concert hall acoustics, which simulates the transmission characteristics between a loundspeaker and a listening position. |
Advances in Vibration Welding Technology | The primary objective of this paper will be to focus attention on recent major advances in vibration welding technology which directly apply to the automotive industry. Breakthroughs in large part welding capabilities, combined with product improvements, now extend the range of current joining possibilities, opening the way for new and innovative automotive product design. Welding reinforcements up to 50” (127cm) long, to an all plastic bumper, has become a reality with the development of a large part vibration welder (LPVW). Currently in production, this new technology and equipment can also be applied to other large part applications, such as welding structural or support members onto large exterior components, i.e.: hood and trunk lids, quarter panels, valence panels and spoilers. Improvements in standard sized welders such as advanced process controls and built-in flexibility will offer significant gains in weld quality, automation, adaptation and overall productivity. A discussion of basic theory and principles of operation will be essential for background Information, along with equipment descriptions ranging from standard welders to special large part vibration welders. Details such as part size capabilities, operating parameters, and equipment selection relative to specific types of applications will be described thoroughly. Examples of successful assembly applications in areas such as fuel management, exterior lighting, ducts, and under-the-hood components will be used for capability familiarization. |
Dolby Noise Reduction in Automotive Applications | In the past decade, the high frequency response of automotive tape playback equipment has been extended, the efficiency of loudspeakers has increased and the cost of high power amplifiers has been reduced. Consequently, tape noise can be a significant problem when listening in the car. This paper discusses the design philosophy of the Dolby B-type and C-type noise reduction systems that are now widely used throughout the in-car entertainment industry to overcome the tape noise problem. Information relating to basic tape parameters, to other approaches to noise reduction and to noise reduction system defects is also included. |
Recent Development of Plastic Material for Automotive Interior Application | In addition to weight reduction and cost reduction, maintenance of the initial quality has become an important subject including color matching after long years of use since automobiles are used for longer years these days. This paper decsribes an outline of our manufacturing process of instrument panel pads, characteristics of the new surface material which we developed for above requirements, quality comparison of the surface material with those by other methods, possibility of applying this new method to other interior parts, for example, door trim, and so on. |
Noise and Vibration Reduction Measures Applied to Diesel Engine Cars | Some instances of the corrective activities concerning the noise and vibration problems such as idle noise, idle shake, driveline rattle, intake noise and booming noise experienced in the development stage of new diesel engine passenger cars are introduced here. |
Application of Acoustic Modeling Methods for Vehicle Boom Analysis | This paper describes a system modeling technique for predicting passenger compartment “boom” for a specific car design prior to the building of a prototype vehicle. Since “boom” — defined here as auditory response in the 20 Hz to 80 Hz frequency range — is dependent on body panel vibrations as well as air acoustic properties, three-dimensional finite element models of both body and air are constructed. These models are incorporated in existing vehicle models which include powertrain and chassis representations of the type previously used for performing shake and harshness analyses. To avoid non-symmetric mass and stiffness matrices, a modal method using auxilliary variables is utilized to couple the acoustic and body models. Included in the paper are discussions of modeling issues unique to structural acoustic simulation as well as several examples of studies in which sound pressure level response to realistic inputs is predicted and reduced by simulated design modifications. Test results are presented for comparison. Finally, graphical presentation of panel acoustic contributions is shown to be a useful tool in selecting possible body structure design changes for “boom” improvement. |
A Review of Glazing Road Use Conditions and Laboratory Simulations | This paper addresses glazing road use conditions and presents the results of a research program which investigated laboratory simulations of road use A review of current testing requirements for glazing used in locations through which driver vision is required is presented to introduce the development of improved glazing performance factors. The focus of this paper is the perceived need to insure the continuing use of realistic safety performance tests as new glazing technology emerges. This paper presents results of test simulations on glass, plastic, and glass-plastic materials using elements of a road use exposure model. Both sequential and non-sequential types of testing were evaluated. |
Application of Finite Element Methods to Vehicle Interior Acoustic Design | This paper describes the capabilities of the finite element method for vehicle interior acoustic analysis. Structural and acoustic finite element models of a van-type vehicle are employed to illustrate the implementation of the method in the design stage. Included as representative examples are studies of the acoustic resonances and forced acoustic response of the compartment cavity, which provide preliminary guidelines for initial compartment acoustic design. At a later stage, when the vehicle structural model has been developed, the finite element models of the structure and the passenger compartment cavity can be coupled for a total vehicle system evaluation. The paper illustrates the accuracy of the coupled model by comparison with the measured response in the van. Finally, the systematic application of this finite element methodology in a computer-aided procedure for the acoustic design of the passenger compartment is discussed. |
Analysis Systems for Acoustic Intensity Noise Measurements | The sound intensity calculation techniques have been implemented on a variety of instruments, but an integrated system application of the intensity technique offers more functional freedom and expandable processing options. This paper deals with a brief background of the system implementation of sound intensity methodology and its general application. |