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Strength and fatigue life prediction is very difficult for stamped structural steel parts because the manufacturing process alters the localized material properties. Traditional tensile tests cannot be used to obtain material properties due to size limitations. Because of this, FEA predictions are most often “directional” at best. In this paper an improved prediction methodology is suggested. With a material library developed from standard homogenous test specimens, or even textbook material property tables, localized strength and plastic strain numbers can be inferred from localized hardness tests(1). The new method, using standard ABAQUS static analysis (not commercial fatigue analysis software with many unknowns), is shown to be very accurate. This paper compares the new process FEA strength and fatigue life predictions to laboratory test results using statistical confidence intervals.

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.