Consideration of the Elastic Compressive Properties of Cars in Frontal Impact 1999-01-0095

This paper examines on a fundamental basis the elastic deformation of car structures during frontal impact and proposes models for the elastic stiffness of cars. The paper shows that the rebound energy and V_r, rebound velocity is a function of the impact force at the instant of maximum dynamic crush and of the elastic stiffness. Theoretical predictions of the level of V_r, rebound velocity and it’s manner of variation with approach velocity, V_a, for full width barrier impact are similar to the pattern of V_r, rebound velocity variation found from staged tests. The implications of the model for V_r, rebound velocity in offset collisions are reviewed and an explanation is provided for both tangential and normal restitution coefficients at angled impact surfaces.