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Tensile tests were performed on DP600 and DP780 dual-phase steels to determine the relative effects of bake-hardening on the static and dynamic material response. The quasi-static test variables were prestrain level, specimen orientation (longitudinal, transverse), and heat treatment (as-received, bake hardened). Dynamic tests were performed at rates ranging from 0.001/s to 500/s, with variables of prestrain level and heat treatment. Increases in the ultimate and yield strength for both DP600 and DP780 were mainly due to prestrain and strain rate effects. The bake-hardening effects varied with the material, amount of prestrain, and strain rate. Crush tests were also performed on DP780 tubes in the as-received and bake-hardened conditions at rates ranging from quasi-static up to 7250 mm/s. The energy absorption was similar regardless of the rate.

Crash simulation models require dynamic material property data to produce realistic predictions. The models often have to simulate multi-layered components that can contain polymers, foams, and metals. This paper describes a pilot study on the dynamic tensile properties of energy absorbing foams. The first phase consisted of the development of tensile test procedures suitable for high rate testing of foams. The second phase involved dynamic tensile tests on foams at rates up to 3.0 m/s. A half-scale ASTM D1623 Type A cylindrical tensile dog-bone was used for the dynamic tests. The pilot study showed that dynamic tests on foam were possible. The dynamic ultimate tensile strength, failure strain, and stiffness of three foams at various rates were measured. The groundwork has been laid for the development of a foam tensile test standard for the automotive industry, with the potential of generating shared databases.