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Five different nonplanar mirrors were evaluated as driver-side rearview mirrors in a field test using Ford employees. Two were spherical convex (differing in radius of curvature), and three were aspheric (differing primarily in the proportion of their surfaces over which radius of curvature was variable). Each participant drove for four weeks with one of the nonplanar mirrors. At three times during the test the participants filled out questionnaires concerning their experience with the mirrors. Driver preferences for the experimental mirrors increased moderately between surveys at one week and at four weeks. At four weeks, all five nonplanar mirrors were preferred to the standard flat mirror by at least a small amount. For each of the five mirror designs there was a large range of opinion. Most notably, a small number of people strongly disliked the aspheric design that involved the largest variable-radius area.

One of the primary reasons that FMVSS 111 currently requires flat rearview mirrors as original equipment on the driver's side of passenger cars is a concern that convex mirrors might reduce safety by causing drivers to overestimate the distances to following vehicles. Several previous studies of the effects of convex rearview mirrors have indicated that they do cause overestimations of distance, but of much lower magnitude than would be expected based on the mirrors' levels of image minification and the resulting visual angles experienced by drivers. Previous studies have investigated mirrors with radiuses of curvature up to 2000 mm. The present empirical study was designed to investigate the effects of mirrors with larger radiuses (up to 8900 mm). Such results are of interest because of the possible use of large radiuses in some aspheric mirror designs, and because of the information they provide about the basic mechanisms by which convex mirrors affect distance perception.

This paper describes a method for measuring the radius of curvature of mirrors by measuring the size of the reflected image. The image is generated by a video camera, captured using an image grabber board and analyzed using custom software on a standard computer. The system is shown to be capable to higher resolution than the current SAE defined spherometer and capable of determining radius of curvature over a smaller area. The latter is particularly important in using the system for measuring aspheric mirrors.

Occupant protection in side impacts have been actively pursued in recent years. Roughly about one third of all automobile crashes involve side collisions. A majority of fatalities in side collisions are due to injuries in the thorax, head and neck region of the occupant. Modeling and simulation are becoming increasingly popular to help develop restraint systems and enhance the value of the design. The use of analytical tools along with laboratory testing can help improve the effectiveness and the speed of developing and implementing a restraint system to help maximize occupant protection. The development of a detailed and state-of-the-art side airbag modeling and its application in occupant safety in lateral collisions are presented in this paper. A very detailed model of a folded side airbag has been developed and the simulation of the unfolding of the airbag was compared with special airbag testing results.

Side impact accounts for a significant source of societal harm, injury and death. To address this issue, Europe and US have introduced legislation to be met for the new vehicle certification. In an effort to meet these regulations and the market demand for safety, Automotive manufacturers have significantly improved vehicle side structure integrity and introduced side impact airbags are for added protection. Today, passenger vans, light truck and sport-utility type vehicles are all popular consumer choices in the US. These vehicles differ significantly from passenger cars in many respects and as such need special design considerations for side airbags. Here, MADYMO-3D model of a generic passenger van / Sport-Utility type vehicle is created and correlated to FMVSS-214 side impact crash test. This model is used to evaluate both door and seat mounted side airbag designs in different orientations at standard test impact condition and at a higher speed.

The paper reports the results of a project investigating means to predict injury risk created by impacting airbags on eyeballs healed after radial keratotomy surgery. In the first phase of the project, a finite element model of an intact eyeball was prepared. Due of the lack of experimental data to calibrate biomechanical models, the model was validated for impact loading using a series of clinical observations related to perforations of the eyeball by small debris from industrial machines. Typical impacts were simulated over the range of observations and the critical dimensions of impacting debris perforating the cornea and the sclera, as observed clinically, were properly predicted numerically. In the second phase, the model of the intact eyeball was altered to introduce radial keratotomy scars. The simulation of impacting airbag were used to determine the loading on the eye and assess the injury risks based on the strains in the eye tissues.

This paper includes madymo simulations and sled tests for airbag depowering. A compact vehicle's driver and passenger airbags, developed for previous FMVSS 208 regulation, were depowered 20% and 30%. Sled tests and madymo simulations were performed with the sine sled pulse for baseline and depowered airbags under unbelted condition. The results of simulation were compared with those of sled tests which were conducted according to the procedure of amended regulation. In addition, so-called “ridedown energy” management technique was introduced to improve the understanding of physical differences between sine sled pulse and vehicle barrier pulse. By comparing the sine pulse with barrier pulse of a compact vehicle and a mid sized vehicle, it was found that the sine pulse is a typical body pulse of a large sized vehicle and a compact vehicle pulse normally has shorter vehicle rebound time and higher deceleration peak than sine pulse because of small energy absorbing spaces in engine room.

This paper discusses the consumer and news media perceptions about air bags that had to be taken into account by the National Highway Traffic Safety Administration in making rulemaking decisions in 1997. Addressing these perceptions was a major concern as the agency made preparations to allow identifiable groups of people at risk from an air bag deployments to have on-off switches installed in their vehicles.

Vehicle sensitivity to brake induced vehicle vibration has been one of the key factors impacting overall vehicle quality. This directly affects long term customer satisfaction. The objective of this investigation is to understand the sensitivities of a given suspension, and steering system with respect to brake induced vehicle vibration, and develop possible solutions to this problem. Design of experiment methods have been used for this chassis system sensitivity study. The advantage of applying the design of experiment methodology is that it facilitates an understanding of the interactions between the hardware components and the sensitivity of the system due to the component change. The results of this investigation have indicated that the friction of suspension joints may affect vehicle system response significantly.

Two beam elements chassis/suspension models with rigid vehicle body representation and finite element tires were studied under proving ground conditions. The only difference between the two models was that one used flexible beam elements and the other used rigid beams. Several proving ground road surfaces were modeled and used in the analysis, including a washboard road surface, a Belgian block type track and a pothole track,. Also analyzed were the low speed driveway-ramp and (relatively) high speed lane-change cases. The proving ground simulation results, and system compliance results as well, were compared between the two models. The differences revealed the importance and necessity of using finite element model (even just using deformable beam elements) to include the component flexibility in conducting vehicle chassis/suspension dynamic analysis.

High mileage NVH performance is one of the major concerns in vehicle design for long term customer satisfaction. Elastomeric bushings and brake rotors are key chassis components which tend to degrade as vehicle mileage accumulates with time. The degradation of these components normally causes the overall degradation of vehicle NVH performance. In the current paper two categories of problems are addressed respectively: road-induced vibration due to bushing degradation, and brake roughness due to rotor wear. A system integration approach is used to derive the design strategies that can potentially make the vehicle more robust in these two NVH attributes. The approach links together bushing degradation characteristics, brake rotor wear characteristics, the design of experiment (DOE) method, and CAE modeling in a systematic fashion. The concept and method are demonstrated using a production vehicle.

In this paper, a design procedure for the optimized light weight front cross member, which is a sub frame of the car chassis, without sacrificing basic functional requirements is presented. As the first step, optimal structural integrity was calculated and extracted using a CAE technique with the available volume constraint of the package layout. Quantitative design loads for the cross member was achieved by measurement. Dynamic load analysis using ADAMS was also performed to determine the loads. Later, these calculated loads were applied to the FEM stress analysis of the cross member. Furthermore, durability analysis was also performed using load profile database measured from ‘Hyundai Motor Co. Proving Ground’. Four constant amplitude durability tests and two static tests were performed on the cross member prototypes to confirm design reliability.

In automotive-, truck-, and rail-vehicle sub-systems involving rotating and sliding surfaces, problems often arise with wear, friction, and noise in various combinations. These problems have been reduced or eliminated by replacing steel, nylon, acetal and other materials with ultra-high-molecular-weight polyethylene (UHMWPE) components. The objective of this paper is to show how UHMWPE can be effectively utilized to eliminate the above problems. We will present advancements in processing and application of UHMWPE with case study examples. Laboratory studies of various material properties will be compared and contrasted with other more common materials. We will also present principles of part design for manufacturability.

A new protocol for assessing the photooxidation characteristics of high performance, exterior automotive basecoat/clearcoats appears to be both reliable and useful in predicting long term weathering performance of such systems. This has allowed quicker utilization of new technologies or process changes to the mutual benefit of vendor and customer. The protocol is based upon measuring the rate of generation of photooxidation products after accelerated weathering, by FTIR spectroscopy.

Previously, a wear-testing standard was defined that is relevant to high performance bearing materials under realistic automotive powertrain conditions [1]. Using this experimental protocol, studies were extended to include the following bearing grade materials, 450FC30 pol-yaryletherketone (PAEK), polyimide (PI), polyamideimide (PAI) (as received and annealed), polyphthalamide (PPA) and a PTFE bronze sinter. Prior to tribological testing, surface defects or skin/core moulding effects were removed using a defined break-in protocol [1]. The data allowed the bearing materials to be ranked in terms of their wear performance. The PAEK and PI exhibited low wear rates suitable for automotive powertrain applications. The PTFE sinter bronze initially exhibited low wear rates but failed catastrophically after short periods of unlubricated sliding contact. The materials PAI and PPA all gave high wear rates at the lowest pv conditions and consistently failed at the higher pv conditions.

The purpose of this study was to analyze and quantify the effects of accelerated weathering on the surface of various “weatherable” polymers currently utilized for molded-in-color exterior automotive applications. Evaluations consisted of gloss/color retention and surface changes after accelerated weathering exposure, with and without intermittent washing, to simulate product life cycle. Results were found to be affected by both polymer type and interim surface treatments. Data are presented as a means to define specific performance and aesthetic capabilities of these various polymers in a mold-in-color environment to optimize material selection for related component applications.

Over the past 20 years, polyvinyl chloride (PVC) has almost replaced metal in stationary glass reveal moldings with dramatic part cost savings on cars and trucks world-wide. The process of assembly is generally simple and convenient but to replace a reveal molding can be difficult. Many times, in order to replace the molding, it may also be necessary to replace or reseal the glass. In short, PVC reveal moldings, relatively inexpensive parts, are very expensive to service. Outside of general assembly and processing issues, there are 5 variables that may cause a failure in the performance of a stationary glass reveal molding. They are as follows: material degradation, crystallization, plasticizer loss, material properties, and molded-in stress. Because of modern standard PVC formulations and the material requirements of most automotive companies, material degradation, crystallization and plasticizer loss do not commonly cause failure. Material properties and molded-in stress do.

Recently, in the automobile industry, developing a plastic material type distinction system has been highly demanded for plastic recycling. We have developed a handy plastic distinction device which distinguishes between polypropylene (PP) and polyurethane (PU) and also distinguishes between 3 types of plastic wheel caps according to the electrostatic capacity and the light reflection pattern of the plastic. The device is operated by a dry battery (9V), so that it can be easily placed in the recovery field of waste automobile plastic parts.

Engineering plastics, such as polybutylene terephthalate (PBT) with high levels of short glass fibers exhibit unusual flow behavior during injection molding which may affect the final properties of moulded pieces. Through short-shots experiments it is obvious that jetting during cavity filling was systematically associated with highly filled materials, while neat polymers fill cavities through the simple laminar flow. Jetting phenomenon was related with very low, if any, post-extrusion swelling of highly filled materials. In order to study the high shear rheological properties of engineering plastics, in conditions similar to industrial processing, an injection capillary rheometer was developed and fixed on an injection machine. In that case, pressure, shear rate, material plastification and injection are representative of the processing. For comparison, standard laboratory rheometer was performed.

This paper discusses the rationale for, and details of, the engineering requirements, program management process (PMP), and validation requirements utilized for designing and bringing to production a new and viable alternative for electrical carriers and shelf packages which together provide an effective modular rear shelf system. Also addressed is how child tether requirements are incorporated into the design without negatively affecting time-to-market considerations or cost. The electrical carrier, traditionally fabricated from stamped steel, can now be functionally improved to accommodate speaker housings, keyless entry module and other feature electrical modules. Proper program management both at Cambridge Industries and the OEM customer (which cannot be identified at this time since the vehicle is in pre-production stage) allowed for advancing this application from steel to plastic in the example provided.