Simulation And Parameters Analysis For Crash Performance Of An Automotive Thin Walled Column

Car safety is the research focus of vehicle development in the twenty-first century, passive safety of car is an important part of safety studies. Frontal crash safety is essential element of passive safety study, the front rails is the most important impact energy absorption components in the car frontal crash, so the research of the front rails collision characteristics is of great significance.The structure and failure state of automotive front rails is similar to thin walled straight beam, thin walled straight beam can be instead of front rails to study safety of it. Currently, the finite element method has been widely used in research and design of body structure. In this paper, the influence of groove length, radius of corner, wall thickness and material strength parameters on the collision performance of thin walled column is systematic studied by using HyperMesh and LS-DYNA. Also, the formulas between collision energy absorbing and material strength and thickness of thin walled straight beam are fitted. Based on the simulation and analysis, the following conclusions can be drawn:thin walled column crash performance relative to the groove length is robust under axial loading. The specific energy absorption (the ratio of energy absorption and mass) of corner part is about three times more than that of plane part, and the radius increases can increase specific energy absorption. So in the simulation study the fillet must be considered. Under the same distance of deformation, there is power function which exponent is less than 1 between energy absorption and strength of material, and the exponent is greater than 1 between energy absorption and thickness of thin walled column.In this paper, the optimal results of thin walled column crash performance is obtained by doing multi-objective optimization with orthogonal and response surface proxy model approximation theory. The design variables of multi-objective optimization is wall thickness, aspect ratio and radius of rectangular pieces of thin-walled straight beam and the objective function is energy absorption, peak load and the average load. The law of section width and aspect ratio influence on the straight beam energy absorption is obtained by the results of orthogonal experiment. The research and conclusions have important guiding significance on the design and improvement of automotive front rails.