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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.

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.

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 discusses a Design for Six Sigma (DFSS) based methodology for designing an injection molded bumper energy absorber to help meet vehicle pedestrian protection requirements. The development process is described, and an example is presented of its use in designing an injection molded energy absorber for a range of various vehicle styling parameters. First, an idealized set-up incorporating the car styling parameters critical for pedestrian protection requirements was developed. Then, the vehicle and Energy Absorber (EA) geometries were parameterized and a DFSS process was employed to investigate the design space using Finite Element Impact Analysis with a commercially available Lower Leg Form Impactor.

This paper describes a bumper system designed to meet the current FMVSS (Federal Motor Vehicle Safety Standard) and ECE42 legislation as well as the European Enhanced Vehicle Safety Committee (EEVC) requirements for lower leg pedestrian impact protection [1] (The EEVC was founded in 1970 in response to the US Department of Transportation's initiative for an international program on Experimental Safety Vehicles. The EEVC steering committee, consisting of representatives from several European Nations, initiates research work in a number of automotive working areas. These research tasks are carried out by a number of specialist Working Groups who operate for over a period of several years giving advice to the Steering Committee who then, in collaboration with other governmental bodies, recommends future courses of action designed to lead to improved safety in vehicles).

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.

The automotive industry is continually striving for opportunities to take additional cost and mass out of vehicle systems. Large parts such as an Instrument Panel retainer are good candidates because a small percent reduction in mass can translate into a significant material mass savings. Multiple requirements for a soft instrument panel including safety, stiffness, adhesion, etc. can make these savings difficult to achieve. This paper will describe how a new material and process development for the fabrication of a soft instrument panel can produce 50% weight savings with a 20% cost reduction potential. In addition, this new technology exhibits improved performance over existing materials during safety testing.

This paper describes a bumper system design that satisfies both current FMVSS legislation as well as the European Enhanced Vehicle Safety Committee (EEVC) requirements for lower leg pedestrian impact protection. The dual performance solution is achieved through a combination of material properties and design. Using Computer Aided Engineering (CAE) modeling, the performance of an injection molded energy absorber (EA) was analyzed for pedestrian protection requirements of knee bending angle, knee shear displacement, and tibia acceleration, 4Kph pendulum and barrier impacts (ECE42, FMVSS), and 8Kph pendulum and barrier impacts (CMVSS, FMVSS). The results demonstrate how an injection molded EA using polycarbonate/polybutyelene terephthalate (PC/PBT) resin (Figure 1) can meet both FMVSS and pedestrian safety requirements and can do so within a packaging space typical of today's vehicle styling.

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.

There are a multitude of opportunities to utilize two-shot or overmolding technology in the automotive industry. Two-shot or overmolding a thermoplastic elastomer onto a rigid substrate can produce visually appealing, high quality parts. In addition, use of this technology can offer the molder significant reductions in labor and floor space consumption as well as a reduction in system cost. Traditionally, two-shot applications were limited to olefinbased TPE's and substrates, which often restricted rigidity, structure and gloss levels. With the development of thermoplastic elastomers that bond to engineering thermoplastics, two-shot molding can now produce parts that require higher heat, higher gloss and greater structural rigidity. This paper will outline engineering thermoplastics that bond with these new elastomers, discuss potential applications, and review circumstances that offer the best opportunity to call upon the advantages of two-shot and overmolding technology.

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.

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.

This paper will describe an approach to satisfying proposed European Enhanced Vehicle Safety Committee (EEVC) legislation for lower leg pedestrian impact. The solution for lower leg protection is achieved through a combination of material properties and design. Using Computer Aided Engineering (CAE) modeling, the performance of an energy absorber (EA) concept was analyzed for knee bending angle, knee shear displacement, and tibia acceleration. The modeling approach presented here includes a sensitivity analysis to first identify key material and geometric parameters, followed by an optimization process to create a functional design. Results demonstrate how an EA system designed with a polycarbonate/polybutyelene terephthalate (PC/PBT) resin blend, as illustrated in Figure 1, can meet proposed pedestrian safety requirements.

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.

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.

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.

As the need for plastic components with high-performance and low systems cost continues to escalate, the issues associated with bringing applications to automotive market have become more complex. Automotive applications such as seamless integral Passive Supplemental Inflatable Restraint (PSIR) systems can have tearseams that are either molded-in or laser scored. Molded-in tearseams in seamless Instrument Panels (IP) eliminate the secondary operation of laser scoring, but they warrant thin wall molding conditions. This paper describes material characterization under thinwall molding conditions wherein the effects of processing on mechanical properties are explored. This paper also discusses results from a proprietary finite element code developed at GE to predict the processing parameters, which affect the mechanical properties of the material at the tearseam in a seamless IP system.

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.

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.

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.