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National Highway Traffic Safety Administration (NHTSA) revised the upper interior head-impact requirements of Federal Motor Vehicle Safety Standard (FMVSS) 201 to reduce abbreviated injury scale (AIS) 3 or greater injuries or fatalities during vehicle collisions. The more-stringent FMVSS 201 requirements have made both OEMs and material suppliers consider new design approaches and new materials with improved performance. This has led to development of several new trim-design options. In this paper we discuss the development of a new headliner substrate material that is believed will meet the FMVSS 201 head injury criterion (HIC) of 1000 or less - a value that is directly equivalent to the AIS 3 scale. Also discussed is how both a headform model and analytical methodology were used to evaluate this new material against existing headliner materials.

A methodology to develop full-vehicle representation in the form of a finite element model for crashworthiness studies has been evolved. Detailed finite element models of two passenger vehicles - 1995 Chevy Lumina and 1994 Dodge Intrepid have been created. The models are intended for studying the vehicle’s behavior in full frontal, frontal offset and side impact collisions. These models are suitable for evaluating vehicle performance and occupant safety in a wide variety of impact situations, and are also suitable for part and material substitution studies to support PNGV (Partnership for New Generation of Vehicles) research. The geometry for these models was created by careful scanning and digitizing of the entire vehicle. High degree of detail is captured in the BIW, the front-end components and other areas involved in frontal, frontal offset and side impact on the driver’s side.

Federal motor vehicle safety standard (FMVSS) 201 [1] stipulates that tests have to be conducted on the upper interior of vehicles to estimate the head injury criteria (HIC) and comply with the requirements of limiting the HIC(d) value to be less than 1000. Multiple impacts at the same location may lead to high values in HIC(d) due to strain hardening of the sheet metal. HIC(d) value is not only dependent on the performance of the countermeasure, but also on the performance of sheet metal underneath the countermeasure. This paper addresses the effect of multiple impacts on the HIC(d) value using finite element analysis. One of the objectives of this paper is to bring awareness of the effect of multiple impacts on head impact performance among the test engineers. A systematic procedure is established to decide vehicle structure change during development testing.