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Engineering thermoplastics are widely used in a variety of automotive components systems because of their excellent balance of mechanical performance, design flexibility, aesthetics, parts integration, and low specific gravity. This combination of properties allows for the creation of highly integrated modules, which can increase assembly efficiency and reduce mass, part count, warranty and ergonomic issues, and systems costs. As a result, the use of engineering thermoplastic materials can enhance market competitiveness at a time of increased global competition. To evaluate the economic advantages of polymers in a specific vehicle system, a design for assembly (DFA) case study was conducted with the goal of determining the variable system cost case for a generic thermoplastic door module system vs. conventional-build door systems based on assembly savings gains. This paper will describe the study and show the results achieved.

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.

The thermal performance of an automotive forward-lighting assembly is predicted with a computational fluid-dynamics (CFD) program. A three-dimensional, steady-state heat-transfer model seeks to account for convection and radiation within the enclosure, conduction through the thermoplastic walls and lens, and external convection and radiation losses. The predicted temperatures agree well with experimental thermocouple and infrared data on the housing. Driven by the thermal expansion of the air near the bulb surface, counter-rotating recirculation zones are predicted within the enclosure. The highest temperatures in the plastic components are predicted on the inner surface of the shelf above the bulb where airflow rising from the hot bulb surface impinges.

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.

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.

Automotive exterior paint systems can significantly affect the impact performance of thermoplastic body panels. To utilize the benefits of predictive engineering as a tool to assist in the design and development of thermoplastic body panels, thermoplastic body panel materials have been characterized with typical automotive paint systems for use for finite element modeling and analysis. Paint systems used for exterior body panels can vary from rigid to more flexible, depending on the vehicle manufacturer's specifications. Likewise, thermoplastics for body panels vary in mechanical properties, primarily depending on the heat performance requirements of the application. To understand the effects of paint systems on impact performance of thermoplastic body panels, two different paint systems, representing “rigid” and “more flexible,” were evaluated on two body panel grades of thermoplastics with different mechanical properties.

The consumption of blow molded bumpers for passenger vehicles is increasing, particularly for small to mid-size vehicles. The performance required for bumpers in this class of vehicles varies by geographic region, as “global” vehicles are increasingly specified outside of the United States. For this reason, it is important to understand the impact performance provided by materials that could be blow molded into bumpers for this class of vehicles. This paper will compare the relative performance of polycarbonate/polybutylene terephthalate (PC/PBT) alloys vs. polyolefins for impact protection, weight, and processing performance.

As automakers struggle to meet often conflicting safety, weight, styling, and performance requirements, engineering thermoplastics (ETPs) are making increasing inroads into applications that once were the exclusive domain of metals, glass, and thermosets. A good example of this is in the door systems area, where the performance, design flexibility, aesthetics, parts integration, and lower specific gravity offered by ETPs are allowing highly integrated and efficient modules to be created that, in turn, increase assembly efficiency and reduce mass, part count, warranty issues, and systems costs. This paper will use several case studies on innovative door hardware modules and door panels to illustrate the advantages offered by this versatile class of engineering materials.

The history behind Polymer Class “A” Body Panels for automotive applications is very interesting. The driving factors behind these applications have not changed significantly over the past sixty years. Foremost among these factors is the need for corrosion and dent resistance. Beginning with Saturn in 1990, interest in polymer body panels grew and continues to grow up to the present day, with every new global application. Today, consumers and economic factors drive the industry trend towards plastic body panels. These include increased customization and fuel economy on the consumer side. Economic factors such as lower unit build quantities, reduced vehicle mass, investment cost, and tooling lead times influence material choice for industry. The highest possible performance, and fuel economy, at the lowest price have always been a goal.

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.

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.

The I-Section bumper design has evolved over the past 10 years into a lightweight, low cost, high performance alternative to traditional bumper beams. Initial I-Section Bumpers were developed with 40% Chopped fiberglass GMT. Through the development of lower cost Mineral-Filled/Chopped fiberglass GMT, improved static load and dynamic impact performance results have been achieved in I-Section Bumper Designs.

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.

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.

A technique for estimating the lateral loads exerted on the vehicle frame during centerline pendulum impacts has been developed. These loads can either be determined by sophisticated hand calculations or by using beam finite-element analysis. The loads can either be determined as a fraction of the peak impact load, or as an absolute number. The dependence of the lateral load on frame stiffness, bumper cross-section, and bumper sweep will be shown to be quite dramatic.

Automotive styling trends point to reduced bumper overhang, greater sweeps, and reduced overall package space for the bumper system. At the same time engineers are charged with improving bumper performance to reduce collision repair costs and enhance occupant safety further. Two key performance parameters for the bumper to meet these conflicting objectives are fast but controlled loading and efficient energy absorption (EA). The majority of today's North American passenger-car bumper systems consist of a reinforcing bar either of steel, aluminum, or composite construction, and an energy absorption media. The most widely used energy-absorber construction is made from an expanded-polypropylene foam (EPP). Honeycomb energy absorbers, which are made from an ethylene vinyl acetate (EVA) copolymer, are also still used on some of today's cars. This paper will address an alternative to the bumper energy absorber systems described above.

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.

This paper documents the design methodology, part performance, and economic considerations for a generic hardware module applied to a front passenger-car door. Engineering thermoplastics (ETPs), widely used in automotive applications for their excellent mechanical performance, design flexibility, and parts integration, can also help advance the development of modular door-hardware systems. Implementation of these hardware carriers is being driven by pressures to increase manufacturing efficiencies, reduce mass, lower part-count numbers, decrease warranty issues, and cut overall systems costs. In this case, a joint team from GE Plastics, Magna-Atoma International/Dortec, and Excel Automotive Systems assessed the opportunity for using a thermoplastic door hardware module in a current mid-size production vehicle. Finite-element analysis showed that the thermoplastic module under study withstood the inertial load of the door being slammed shut at low, room, and elevated temperatures.

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).

This paper will discuss, compare, and contrast current materials, designs, and manufacturing options for fuel filler doors. Also, it will explore the advantages of using conductive thermoplastic substrates over other materials that are commonly used in the fuel filler door market today. At the outset, the paper will discuss the differences between traditional steel fuel filler doors, which use an on-line painting process, and fuel filler doors that use a conductive thermoplastic substrate and require an in-line or off-line painting process. After reviewing the process, this paper will discuss material options and current technology. Here, we will highlight key drivers to thermoplastics acceptance, and look at the cost saving opportunities presented by the inline paint process option using a conductive thermoplastic resin, as well as benefits gained in quality control, component storage and coordination.