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The drive to reduce costs and increase efficiency in the automotive industry is often the driving force for development of new technologies and methods of engineering. Polypropylene (PP) is widely used as a low cost alternative to “engineering” thermoplastics. This paper outlines the characterisation methods used to develop material models for talc-filled impact-modified PP, which are then used to increase the efficiency of the development process, by using engineering analyses to reduce the prototyping costs and potentially the development time for an application. Instrument panels (IPs), door panels and trim parts are usually subjected to heat requirements and must maintain dimensional tolerance levels for each application. This necessitates extensive prototype testing and often several design iterations in order to reach the requirements. This paper deals with the characterisation of PP creep behaviour and development of a model for use in Finite-Element (FE) - based codes.

The functional performance of the instrument panel has been changing dramatically since the late 80s, with FMVSS 208 legislation and its related impact on the addition of air bags and knee bolsters. In addition to addressing occupant safety legislation through more safety components, as well as navigation, security, comfort, informational and other systems are being added to the instrument panel as the consumers' desire for enhanced features continues. At the same time, consumers still want a product that is uncomplicated, affordable, aesthetically pleasing and - at the same time - doesn't limit valuable interior compartment space. The early efficient integration of these components (electrical, architecture, HVAC, steering) in the design, engineering and assembly process will be the areas of requirement that will have a primary effect on IP system cost in the future.

The passage of FMVSS 201 Extended Rule in November 1993 resulted in the evaluation of a variety of designs and materials for use in the interior trim components such as A and B pillars. Historically these parts had requirements for aesthetics, dimensional stability, and thermal performance. Structural performance with energy absorbing capability to prevent head injury is now a significant addition to these requirements. Visibility concerns limit the amount of packaging space available for implementing countermeasures in this area. Designing countermeasures by trial and error involves extended development time and significant expenditures. This paper discusses the use of the finite element analysis technique that is being increasingly used to accurately simulate head impact situations. The use of high strain rate material property (true-stress, true-strain curves) data is necessary for dynamic impact simulation analysis.

Close-out panels, or knee bolsters, have become an important component of structural instrument panels. Using plastic in these structures has proven successful but can be costly to develop by trial and error technique. Estimating their behavior through mathematical modeling software is one way to reduce development time and cost. This paper discusses the correlation of test parts which have similar structures to bolsters used in production today with results of finite element analysis (FEA) modeling.

The advent of airbags in passenger vehicles has resulted in the need for instrument panel components which are capable of handling high rate, high load impact in order to control kinematics of the occupant and air bags. This paper summarizes information from the development of thermoplastic structures to be utilized in impact areas of instrument panels. It discusses design, molding, and analysis considerations along with presentation of data obtained from testing injection molded parts.

With the implementation of air bags into today's vehicles, the functional requirements of the instrument panel have changed significantly. Screening of different candidate systems is difficult due to the expense and time involved in testing to the FMVSS requirements. Plastic material properties also vary with temperature and strain rate which increases the complexity of the testing required. It is the objective of this paper to investigate the response of PC/ABS blends to this environment. Also, a summary of mathematically modeling plastic materials with commercial software in energy management environments is presented. This paper will discuss the results of testing PC/ABS blends at strain rates and temperatures typical to that of impact conditions and correlation of these tests to different material models used in finite element codes.