Numerical Analysis for Evaluating the Cumulative Impact Damage of Automotive Bumpers

We performed numerical analyses using an explicit code to evaluate the cumulative impact damage of an automotive front-end bumper during low-speed crash events, as described by CMVSS215. The CMVSS215 regulation consists of a series of test cases for the same parts. To evaluate the crash performance of a bumper, we used a coupled numerical analysis scheme and considered several matters such as the removal of residual vibrations and the evaluation of the bumper back beam recovery. We also used an EWK rupture model in the PAM-CRASH code to improve our damage and fracture estimates. Tensile test experiments were conducted to tune the performance of the EWK rupture model; the resulting material properties and fracture criterion were incorporated into the numerical analyses of the low-speed frontal crash events. The coupled analysis scheme was verified by comparing the output with bumper impact test data. The results indicate that the EWK rupture model is a good candidate for several applications.