The Structure Optimization Of Energy Absorbing Box Of Bumper On Low Speed Crash

With the rapid increasing of vehicle, road traffic accidents in china has show a rising trend. As a effective approach reducing injure of vehicle collision accident, study of security vehicle body is significant. Meanwhile, As a technical barrier of auto industry, the level of collision safety influence the performance of domestic auto market. Therefore, from this two perspective, well crashworthiness design of vehicle structure and safety research related technology has both important theoretical and practical significance.In this paper, regarding the key absorbing energy component (crash-box) in the front vehicle bumper system as object of study, various factors that influence the absorbing property of crash-box were analyzed. On that basis, combined with the regulatory requirements of RCAR(Research Council of Automobile Repairs) regulation, using of the multi-program comparison,and optimal selection with optimization theory,these two ideas to to expand the optimization of various factors (section shape, pattern of welding fabrication, predeformation and wall thickness) which are absorption of energy absorption characteristics. The following specific research work:Firstly, studied the implementation process of standard crash experiment required by RCAR.Built the platform of FEA simulation used in this paper with the current mainstream software in crash simulation filed, and tested using this platform to prove that the collision simulation of the entire process is efficient., introduced the model of vehicle finite element model of the necessity and the principle of simplification,and detailed description of the process from the two levels from the combination of theory and application simulation platform for this paper.Secondly, the discipline that this three factors (section shape, pattern of welding fabrication, predeformation and wall thickness) affect the energy absorbing indicators (maximum energy absorption quantity and peak impact force).The best option of this three factors is selected by comparing a variety of possible option. Simulation result show that the best option of energy absorbing property to be much better than the original program.Finally, based on 21 sample points that obtained by average separation of single factor DOE, the proximate mathematical model of relationship between thickness and energy absorbing property is established by adopting the Moving Least Squares method. Then, using the proximate mathematical model to execute iterative optimization by Feasible Direction optimization algorithm obtains the optimal thickness value of crash-box wall. The test results verify that the optimization method based on approximate mathematical model is feasible and effective.