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This paper deals with the effects of various approaches for modeling of strain rate effects for mild and high strength steels (HSS) on impact simulations. The material modeling is discussed in the context of the finite element method (FEM) modeling of progressive crush of energy absorbing automotive components. The characteristics of piecewise linear plasticity strain rate dependent material model are analyzed and various submodels for modeling of impact response of steel structures are investigated. The paper reports on the ranges of strains and strain rates that are calculated in typical FEM models for tube crush and their dependence on the material modeling approaches employed. The models are compared to the experimental results from drop tower tests.

Afin de determiner comment les aciers revetus de zinc ou d'alliage de zinc reagissent avec les materiaux des matrices de formage en presence de lubrifiants, des essais sont realises sur une gamme d'aciers doux revetus par immersion a chaud ou par electrogalvanisation et lors de differentes conditions de formage avec des outils prototypes en acier dur ou tendre et differents lubrifiants

Frictional characteristics and galling tendencies were examined for three sheet metal forming die materials ― cast steel, gray cast iron, and nodular cast iron ― with four die treatments ― unhardened, flame hardened, ion nitrided, and chrome plated. Repetitive testing was performed using a draw bead simulator and an electrogalvanized, free zinc coated steel with a nominal coating weight of 70 g/m 2 per side