High Strain Rate Deformation Behaviour of Steels for Auto-Body
Hiroshi TAKECHI, Manabu TAKAHASHI, Kouichi ITO, Takao ENDO, Yo TOMOTA
It has been one of the major interests in automobile industries to improve crashworthiness of auto-bodies as well as the fuel consumption. Crash energy absorption of a component depends not only on the geometry but also the mechanical properties of the materials used. Buckling of thin wall tube structures, which is a typical example of the deformation during crash, is studied theoretically to clarify the effect of strain rate dependence of flow stress. Geometrical and material factors that control the energy absorbing property of components are reviewed. Flow stress at a strain rate up to approximately 103/s can be estimated by using thermal activation models for dislocation motion. Theoretical background and problems remained for application of the models are briefly reviewed. These methods are of use for machine design coupled with materials selection and/or development when high-speed deformation like automobile collision is taken into consideration.