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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.

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.

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.

Electrostatic painting of exterior body components is considered standard practice in the automotive industry. The trend toward the use of electrostatic painting processes has been driven primarily because of environmental legislation and material system cost reduction efforts. When electrostatically painting thermoplastic body panels, side by side with sheet metal parts, it is imperative that the thermoplastic parts paint like steel. Electrostatic painting of thermoplastics has traditionally required the use of a conductive primer, prior to basecoat and clearcoat application. The use of conductive plastics eliminates the need for this priming step, while improving paint transfer efficiency and first pass yield. These elements provide an obvious savings in material and labor. The most significant benefit, is the positive environmental impact that occurs through the reduction in the emission of volatile organic compounds (VOC's).

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.

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 evolution toward the use of electrostatic painting processes has been driven primarily by environmental legislation and efforts to improve efficiencies in the painting process. The development of conductive substrate material compliments the industry trend toward a green environment through further reductions in emissions of volatile organic compounds during the painting process. Traditionally, electrostatic painting of thermoplastics requires that a conductive primer be applied to the substrate prior to topcoat application. The conductive polymer blend of polyphenylene ether and polyamide provides sufficient conductivity to eliminate usage of conductive primers. Additional benefits include improved transfer efficiencies of the primer and top coat systems, uniform film builds across the part, and improved painting of complex geometries.

The formulation of injection moldable thermoplastics with small loadings of graphite nanotubes provides sufficient conductivity in molded parts to allow for use in electrostatic painting applications. Normally, plastic parts need to be painted with a conductive primer prior to the electrostatic painting of base and clear coats. The use of conductive plastics eliminates the need for the priming step, and improves paint transfer efficiency and first pass yield. These elements provide obvious savings in materials and labor. What is less obvious, however, is the dramatic positive environmental impact that can occur through the reduction in emissions of volatile organic compounds (VOCs). Graphite nanotube technology provides advantages over other technologies such as conductive carbon black. In order to reach the percolation threshold for conductivity in carbon-black-containing resins, the loading of carbon black required tends to embrittle the polymer.

Automotive engineers and designers are working to develop pillar-trim concepts that will comply with the upper interior head-impact legislation, FMVSS 201U. However, initial development cycles have been long and repetitive. A typical program consists of concept development, tool fabrication, prototype molding, and impact testing. Test results invariably lead to tool revisions, followed by further prototypes, and still more impact testing. The cycle is repeated until satisfactory parts are developed - a process which is long (sometimes in excess of 1 year) and extremely labor intensive (and therefore expensive). Fortunately, the use of finite-element analysis (FEA) can greatly reduce the concept-to-validation time by incorporating much of the prototype and impact evaluations into computer simulations. This paper describes both the correlation and validation of an FEA-based program to physical free-motion head-form testing and the predictive value of this work.

The purpose of this paper is to discuss design methodology, manufacturing considerations, and testing proveout for a prototype gas-assist-molded, energy-absorbing, glovebox door program. The design used a single gas pin mounted in a multiple-gas-channel component and an internal gas manifold to form an efficient energy absorbing system. The end goal for the development program was to manufacture a glovebox door in a system that could meet the customer's targets for cost, surface appearance, and safety considerations without degrading function and fit. This paper will discuss the ability of a design methodology to predict actual component performance using engineering calculations, analytical tools, and prototype testing/molding during the development.

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.

An Instrument Panel (IP) cockpit is one of the most complex vehicle systems, not only because of the large number of components, but also because of the numerous design variations available. The OEM can realize maximum benefit when the IP cockpit is assembled as a module. This requires increased performance attributes including safety, durability, and thermal performance, while meeting styling and packaging constraints, and optimizing the program imperatives of mass and cost. The design concept discussed in this paper consists of two main injection molded parts that are vibration welded to form a stiff structure. The steering column is attached to the cowl and plastic structure by a separate steel column support. The plastic IP structure with integrated ducts is designed and developed to enable the IP cockpit to be a modular system while realizing the benefits of mass and cost reduction.

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.

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.

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

Textron Automotive Trim, Valeo Climate Control, and Torrington Research Company, with assistance from GE Plastics, have developed an integrated instrument panel system to meet ever-increasing industry targets for: Investment and piece-cost reduction; Mass/weight savings; Quality and performance improvements; Packaging and space availability; Government regulation levels; and Innovative technology. This system, developed through feedback with the DaimlerChrysler Corporation, combines the distinctive requirements of the instrument panel (IP) with the heater-ventilation-air-conditioning (HVAC) assembly. Implementing development disciplines such as benchmarking, brainstorming, and force ranking, a number of concepts were generated and evaluated. Using a current-production, small, multi-purpose vehicle environment, a mainstream concept was designed and engineered.

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.

The high costs of prototyping, revisions, and production tooling, with a higher emphasis on quality, concurrent with demands for miniaturization, higher-density packaging, stricter performance, and a shortened product development cycle, have led to the development of advanced analysis techniques that address the performance issues associated with failure prevention in automotive connectors. Because of the complex material and geometric nonlinearity demands in performance, traditional calculations are inadequate, and new methods, utilizing finite element analysis techniques were developed. These highly specialized analysis techniques will enable the designer and engineer to predict connector performance with a high degree of confidence. Concurrent with concept designs, structural analyses (in the areas of assembly, disassembly, and terminal retention) must be done prior to design release.

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.

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.