Discussion on Strain Rate Effects in Numerical Simulation of Vehicle Crash

The Cowper-Symonds constitutive equation is used for simulation of vehicle crash. The effects of strain rate sensitivity to the behavior of vehicle structure in material modeling in the frontal impact are investigated. As an illustrative example, a series of impact analyses of the front rail of a vehicle are carried out. The results show that the energy absorption and the loading capacity of the structure are significantly influenced by strain rate. The effects of strain rate to a full vehicle frontal crash analysis are then investigated. Two analyses are performed with the same FE model. One considers strain rate effect and another without strain rate effect. The results from this study indicate that when incorporating strain rate in the frontal crash analysis, computed crush displacement, velocity, and the deceleration of vehicle are closer to test results than those without strain rate effect.