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This paper will address several critical aspects of bumper system performance, including vehicle damage protection and crash-severity sensing considerations, energy-absorption capacity and efficiency, and low-speed impact consistency and sensitivity to temperature changes. The objective is to help engineers and designers establish a realistic perspective of the capability of the various technologies based on actual test performance. The scope of the evaluation will include a comparison of several bumper-beam material constructions when subjected to a 16-km/hr swinging barrier impact over a range of temperatures the bumper could see in service (-30 to 60C).

The first single-piece, injection-molded, thermoplastic, front bumper for a light truck provides improved performance and reduced cost for the 1997 MY Explorer® Ltd. and 1988 MY Mountaineer® truck from Ford Motor Company. Additionally, the system provides improved impact performance, including the ability to pass 5.6 km/hr barrier impact tests without damage. Further, the advanced, 1-piece design integrates fascia attachments, reducing assembly time, and weighs 8.76 kg/bumper less than a baseline steel design. The complete system provides a cost savings vs. extruded aluminum and is competitive with steel bumpers.

Over the last decade, on small- and medium-size passenger cars, a new class of front bumper - injection or blow molded from engineering thermoplastics - has been put into production use. These bumper systems provide full 8-km/hr federal pendulum and flat-barrier impact protection, as well as angled barrier protection. Thermoplastic bumpers, offering weight, cost, and manufacturing advantages over conventional steel bumper systems, also provide high surface finish and styling enhancements. However, there remain questions about the durability and engineering applicability of thermoplastic bumper systems to heavier vehicles. This paper presents results of a preliminary study that examines the durability of thermoplastic bumpers drawn from production lots for much lighter compact, and mid-size passenger cars against baseline steel bumper systems currently used on full-size pickup truck and sport-utility vehicles (SUVs). Bumpers were subjected to U.S.

This paper presents results from a series of tests that address safety related issues concerning vehicle glazing. These issues include occupant containment, head impact injury, neck injuries, fracture modes, and laceration. Component-level and full vehicle crash tests of standard and polycarbonate non-windshield glazing were conducted. The tests were conducted as part of a study to demonstrate that there is no decrease in the safety benefits offered by polycarbonate glazing when compared to current glazing. Readers of this paper will gain a broader understanding of the tests that are typically conducted for glazing evaluation from a safety perspective, as well as gain insight into the meaning of the results.

Thermoplastic body panels are emerging in the industry as automotive manufacturers seek to design for advanced aerodynamic styling, lower weight, and cost effective vehicles. To best exhibit the advantages of GE thermoplastic resins in these applications, an extensive study has been completed to demonstrate the impact performance of thermoplastic body panels in the field based on the current success with the Buick LeSabre T-Type, Buick Reatta, and the Cadillac Deville and Fleetwood models using NORYL GTX® 910 resin fenders. This study provides a “real life” scenario of the advantages of thermoplastics compared to steel in body panel applications.

This paper presents a novel approach to design an efficient energy absorber using thermoplastic (PC/PBT - Polycarbonate/ Polybutylene Terephthalate) material. Automotive industry always demands minimum package space between bumper beam and fascia from styling perspective. This requires an efficient energy absorber, which can meet the energy absorption target through an idealized force-intrusion performance. In the present study, thermoplastic energy absorber with sequential failure is designed through geometrical configuration to achieve the idealized Force-Deformation (FD) curve. CAE techniques are used extensively for optimizing the design parameters of energy absorber to achieve the desired performance level. The results in the form of FD curve are compared with the idealized curve and the efficiency is calculated. Comparative studies are also performed with foam energy absorber solution.

Currently, automobile manufacturers receive automotive headlamp assemblies from headlamp manufacturers with outer lenses produced of clear or slightly blue tinted polycarbonate. Such headlamp designed to provide optimized light output have very similar aesthetics, and leave little room to differentiate one car platform from another, using the outer lens color. With edge glow technology a car manufacturer can provide an appealing aesthetic look (edge glow effect) from the outer lens. Additionally, this technology can be used to improve the quality of the beam color emitted through the outer lens. Dependent on the chosen combination of halogen source and lens formulation, a range of beam colors spanning from halogen to HID is attainable, where the beam pattern and color continue to conform to the applicable SAE and ECE beam photometry and color standards and regulations.

This paper examines a variety of thermocouple and infrared measurement techniques as means of obtaining accurate and consistent temperature measurements within a headlamp system. While measuring temperature is straightforward in principle, in practice, these measurements are fraught with potential error. The paper summarizes a succession of experiments conducted at our Parts Design Center (formerly the Application Development Resource Center) in Pittsfield, MA. These experiments lead to the ability to accurately measure temperature at a given location within a lamp assembly. Using these studies and the resulting transfer functions as a foundation, a Design of Experiment (D.O.E.) is presented which explores the effect of a variety of headlamp design factors on the surface temperature of a headlamp reflector at a given location.

OEM and Tier One integrated suppliers are in constant search of cockpit system components that reduce the overall number of breaks across smooth surfaces. Traditionally, soft instrument panels with seamless airbag systems have required a separate airbag door and a tether or steel hinge mechanism to secure the door during a deployment. In addition, a scoring operation is necessary to ensure predictable, repeatable deployment characteristics. The purpose of this paper is to demonstrate the development and performance of a cost-effective soft instrument panel with a seamless airbag door that results in a reduced number of parts and a highly efficient manufacturing process. Because of the unique characteristics of this material, a cost-effective, lightweight solution to meet both styling requirements, as well as safety and performance criteria, can be attained.

Automotive styling and performance trends continue to challenge engineers to develop cost effective bumper systems that can provide efficient energy absorption and also fit within reduced package spaces. Through a combination of material properties and design, injection-molded engineering thermoplastic (ETP) energy absorption systems using polycarbonate/polybutylene terephthalate (PC/PBT) alloys have been shown to promote faster loading and superior energy absorption efficiency than conventional foam systems. This allows the ETP system to provide the required impact protection within a smaller package space. In order to make optimal use of this efficiency, the reinforcing beam and energy absorber (EA) must be considered together as an energy management system. This paper describes the development of a predictive tool created to simplify and shorten the process of engineering efficient and cost effective beam/EA energy management systems.

Automobile headlamps are highly controlled products that must meet various performance standards to be commercialized. The combination of the bulb and lens must emit acceptable color and light output. Commercially available headlamps use different types of bulbs but usually a clear or slightly tinted lens. In the past few years, high performance bulbs have been used. These are known as HID or xenon lamps and are characterized by their bluer color compared to standard halogen bulbs. This paper explores some of the possibilities that new lens material can offer in terms of design and aesthetics with little or no impact on lighting performance as tested per the Society of Automotive Engineers (SAE) J1383 [1]. Light stability of these new lens materials is also discussed.

Three commonly used energy management systems (expanded polypropylene foam, collapsing honeycomb and hydraulic shock absorbers) were fully characterized in 2.2 m/s pendulum bumper impact testing. This work was done to better understand the dynamic energy transfer and absorption of the system components and any synergies which exist between them. The test results showed that the energy absorbing systems which exhibited the best load and deflection performance when considered as individual components do not always work the most synergistically with the reinforcement beam. Simply examining the energy absorber's performance alone did not truly reflect the ability of the beam/absorber system's ability to manage energy.

Automotive industry is looking for weight out options to increase the fuel efficiency of automobiles. Thermoplastics usage is increasing to reduce the dead weight of different automotive components. Traditional steering wheel can be replaced with thermoplastic to make it lighter without compromising its performance requirements. Thermoplastic steering wheel offers overall reduction in cost as well as significant reduction in mass. In addition, thermoplastic steering wheel also offers part integration and styling flexibility. As steering wheel has to meet variety of loading criteria (vibration, static loading, dynamic loading and fatigue), the overall design is a multi objective optimization process. Major challenges of thermoplastic steering wheel are to design the effective model for any particular wheel geometry domain defined by OEM's (Original Equipment Manufacturer) styling studios.

The automotive industry continues to strive for mold-in-color (MIC) solutions that can provide metallic flake appearances. These MIC solutions can offer a substantial cost out opportunity while retaining a balance of weathering performance and physical properties. This paper discusses a predictive engineering package used to hide, minimize and eliminate flow lines. Material requirements and the methods used to evaluate flowline reduction and placement for visual inspection criteria are detailed. The Nissan Quest® luggage-rack covers are used to illustrate this application. The paper also explores how evolving predictive packages offer expanding possibilities.

Recent vehicle design trends require bumper systems to be crashworthy under more demanding circumstances, e.g. tighter package space, heavier vehicle mass, and wider rail spans. Meanwhile, pressure to reduce cost and weight of bumpers continues at a time when roles in the supplier community are changing. These factors have combined to increase the importance of optimizing bumper design and material properties for specific platforms. Materials suppliers have responded by developing a range of specialized engineering thermoplastic (ETP) resins that can help meet increasing performance requirements yet also offer the potential for improved manufacturing productivity, significant weight savings, and systems cost reductions. Material suppliers have also increased the level of technical design support provided to OEMs and 1st Tier suppliers.

Engineering thermoplastics are being used increasingly in automotive exterior body applications; most of these applications require that the panels be painted “on line” with the rest of the car body at relatively high temperatures. The high temperatures associated with the painting/conditioning of the car have been shown to cause dimensional stability problems on automotive fenders molded from NORYL GTX®. This paper contains the results of an extensive FEA investigation targeted at determining what factors cause dimensional problems in fenders exposed to high heat. The ABAQUS FEA software was used to perform computer simulations of the process and the C-PACK/W software was used to determine molded in stress values.

The C-section bumper design has developed through an evolutionary process and has come to be regarded as a reasonable geometry for frontal bumper impacts, especially for use with glass-filled sheet-stampable thermoplastic composite materials. C-section bumpers are now well proven and accepted in the automotive industry, performing satisfactorily in a variety of crash situations. A new and more complicated cross-section geometry (I-type with multiple ribbing) has recently been proposed for glass-filled thermoplastic composites. While, in some specialized cases, these highly engineered bumper cross-sections can be useful, they may not perform adequately in all reasonable crash scenarios. Further, it is important to consider manufacturing limitations and the realities of material performance in such complex geometries. Data will be presented to question the practical advantages of the use of ribbed bumper designs over the traditional C-section beam.

The August 1996 expansion of FMVSS 201 established head impact performance criteria for upper interior components This standard has forced automotive manufacturers, designers, and suppliers to change their thinking for interiors, especially pillars, compliance with FMVSS 201 will require new, structural designs and energy-absorbing materials An ongoing study has examined the implications of FMVSS 201 and its effect on pillars The results of this study have demonstrated how energy-absorbing engineering thermoplastics can be used to meet and exceed the requirements of the head impact legislation through single-piece pillar trims

A conceptual step-pad bumper system has been designed for a sport utility vehicle. This bumper incorporates an all-thermoplastic solitary beam/fascia with a Class A finish and a replaceable, grained thermoplastic olefin (TPO) or urethane step pad. The rear beam is injection molded and the cover plate features integrated through-towing capabilities and electrical connections. The bumper is designed to pass FMVSS Part 581, 8 km/h impacts. The system can potentially offer a 5.0-13.6 kg weight savings at comparable costs to conventional step-pad bumper systems. This paper will detail the design and development of the concept and finite-element analysis (FEA) validation.

Designers and engineers encounter many challenges in developing vehicles for the small-car market. They face constant pressure to reduce both mass and cost while still producing vehicles that meet environmental and safety requirements. At the same time, today's discriminating consumers demand the highest quality in their vehicles. To accommodate these challenges, OEMs and suppliers are working together to improve all components and systems for the high-volume small-car market. An example of this cooperative effort is a project involving an integrated structural instrument panel (IP) designed to meet the specific needs of the small-car platform. Preliminary validation of the IP project, which uses a compression-molded, glass-mat-thermoplastic (GMT) composite and incorporates steel and magnesium, indicates it will significantly reduce part count, mass, assembly time, and overall cost.