The crashworthiness of vehicles with finite element method depends on the geometry modeling and material properties. In order to ensure the impact characteristics of auto-body structures by a finite element method, the dynamic behavior of sheet metals must be examined. In this paper, high strain rate tensile tests have been carried out with a tension type split Hopkinson bar apparatus specially designed for sheet metals. Simulation of auto body structures has been carried out by an elasto-plastic finite element method with explicit time integration. The crashworthiness of auto-body structures analyzed with quasi-static constitutive relation is compared with the one with rate dependent constitutive model. The frontal frames , the hood and a square tube used in numerical simulation. The impact characteristics such as the deformed shapes and the impact energy absorption of auto-body structures are investigated with the variation of the strain rate.