Hot Stamping Process Research And Yield Stress Distribution Optimization Of Side Impact Beam

With the increasing number of automobile, the trend of impact accidents caused by automobile in all kinds of traffic status is raising. Side-impact collisions are the second leading cause of death and injury in the traffic accidents after frontal crashes. Side impact beam are developed to reduce the velocity and depth of door intrusion into the passenger compartment in side impact crashes. Assessing the effectiveness of side impact beam is significant for reducing occupant fatalities and serious injuries.In order to impove its side crashworthiness, a method using the hot formed side impact beam was proposed. The method produces the side impact beam with uniform thickness and varying yield strength by different cooling rate at hot forming. To make the distribution of the yield strength in the hot formed side impact beam reasonable, an optimization design was performed by the finite element analysis.Ultra high strength steel was successfully produced by using hot stamping process. The microstructure of the samples was analyzed by microscope, and the tension strength and the hardness distribution of the samples were tested. The static character of side impact beam is analyzed by LS-DYNA through the interface of Hypermesh and LS-Prepost. The finite element model was built up according to FMVSS-214 and validated by the test data.Based on the above results, an optimal distribution of the yield strength in the side impact beam material was obtained using the numerical optimization method of response surface and component collision simulation analysis. Before and after improvement simulation results show that the displacement, crashworthiness force and the effect of energy absorption are increase. The obtained results indicate that the crashworthiness of the front door and the whole car's side can be improved by optimizing the side impact beam and finding the best distribution of material strength in certain range.