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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.

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.

Automotive interiors are undergoing rapid transformation with the introduction of invisible PSIR integral systems. This styling trend requires continuous class A surface for the Instrument Panel (IP) and introduces complexities in the design and analysis of PSIR integral systems. The most important criterion for airbag doors is that it must open as intended, at the tearseam, within the deployment temperature range and without fragmentation. Consequently it is imperative that in analytical simulations, the finite element model of the tearseam is accurate. The accuracy of the model is governed by (a) optimal level of refinement, (b) surface geometry representation and (c) material model. This paper discusses modeling methodology for tearseams with respect to mesh refinement and the effect of geometry.

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.

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.

A new front bumper, blow molded from an engineering thermoplastic, is being used to provide full 8 km/h federal pendulum and flat-barrier impact protection, as well as angled barrier protection on a small passenger car. The low intrusion bumper is compatible with the vehicle's single-sensor airbag system and offers a 5.8 kg mass savings compared with competitive steel/foam systems. This paper will describe the design and development of the bumper system and the results achieved during testing.

Traditional knee bolster designs consist of a first-surface plastic component covered by paint or vinyl skin and foam, with a subsurface steel plate that transfers knee loads to 2 steel crush brackets. The design was developed to meet FMVSS 208 and OEM requirements. More recently, technological developments have allowed for the steel plate to be replaced by a ribbed plastic structure, which offers cost and weight savings to the instrument panel system. However, it is still a hybrid system that combines plastic with the 2 steel crush brackets. This paper will detail the development of an all-plastic design, which consolidates the plastic ribbed reinforcement plate with the 2 steel crush cans in a single engineering thermoplastic component. The new system is expected to offer further cost and weight savings.

As a result of the increased reliance on predictive engineering to reduce vehicle development resources, increasingly accurate predictive finite element models are important to help engineers meet cost and timing restrictions. For components made of engineering thermoplastics, accurate material modeling that helps predict part performance is essential. This material modeling accuracy is even more important where high speed and high loading conditions exist such as in airbag doors, knee bolsters and pillar trim. This paper addresses material modeling of engineering thermoplastics for finite element models that are subjected to high impact and high speed loading. Here, the basics of plastics behavior are introduced and a comparison of the accuracy of different material characterizations in an impact loading is presented. The material under analysis here is a polycarbonate - acrylonitrile butadiene styrene blend, PC-ABS.

Using a combination of engineering test experience, explicit finite-element analysis, and advanced materials characterization, a predictive engineering method has been developed that can assist in the development of active top pads. An active top pad is the component of the instrument panel that covers the passenger airbag module and articulates during a crash event, allowing the airbag to deploy. This paper highlights the predictive analysis method, analytical results interpretation, and suggestions for future development.

An efficient energy absorber (EA) will absorb impact energy through a combination of elastic and plastic deformation. However, the EA is typically coupled with a steel reinforcing beam, which can also elastically and plastically deform during an impact event. In order to design and optimize an EA/Beam system that will meet the specified vehicle impact requirements, the response of the entire assembly must be accurately predicted. This paper will describe a finite element procedure and material model that can be used to predict the impact response of a bumper system composed of an injection molded thermoplastic energy absorber attached to a steel beam. The first step in the process was to identify the critical material, geometric, and boundary condition parameters involved in the EA and Beam individually. Next, the two models were combined to create the system model. Actual test results for 8km/hr.