High Strain Rate Properties of High Strength Steel Sheets

Abstract

High strain rate properties of sheet steel largely depend on its strength level and strengthening mechanisms. The strain rate sensitivity of flow stress has a close relation with the hardness of a softer phase, which indicates superior strain rate sensitivity of multi-phase steels such as DP and TRIP steels. Simple-shear tests have revealed an increase of the flow stress with strain even for ultra high strength steel at large strains. Based on these experimental evidences and physical understandings, an appropriate constitutive model for crash simulation is proposed and discussed.