Research On Properties Of Automobile Energy Absorber Under Low Speed Impact

As the rapid development of Chinese automobile industry, the automobile impact had been an important problem in vehicle research field. At present, most of the research work focus on the high speed impact in China; only few of reseach work are baout low speed impact. Therefore, the low speed impact problems are researched in this paper.The Finite Element Method is applied in this research. Aiming at low speed impact, the structural and material characters of automobile energy absorber are analysed under the platform of LS-DYNA, especially the material characters, and the optimum design paln is proposed.In the research on structural properties, the energy absorber is simplified to be thin-walled beams. The impact process is simulated by Finite Element Method, and the simulative results are obtained. Comparing with the results obtained by numerical calculation method, the correctness of Finite Element Method is validated.The material strain rate and bend strength, which influence the absorbing capability of energy absorber, are researched, and the absorbing performances of energy absorber with different strain rate and bend strength are calculated. Based on the calculation results, the material model is improved and the energy absorber which has better absorbing capability is obtained.The optimum design plan is proposed from both structural and material aspects. As to the structural aspect, in order to reduce the peak impact force, derivational groove is added to energy absorber with medial welding line. About the material aspect, the absorbing ability of mild steel and aluminum alloy is compared. By analyzing the aluminum alloy model with different sections, it is obtained that absorbing performance of aluminum alloy model with hexagon section is the optimum design plan. At last, the energy absorber of a certain car is researched, and primary improving suggestions are proposed. The research results in this paper provide the theoretical basis and referenced data to research the bending characters of automobile front bumper under low speed impact.