Structural Optimization Design Of Automobile Crash Box Under Low-Speed Collision

With the continuous development of the times and economy,automobiles have become an indispensable tool in people's lives.While automobiles bring convenience to people,they also bring environmental pollution,travel safety and other issues,especially the occurrence of low-speed collisions is becoming more and more frequent.Crash box is a component that plays an important role in the low speed collision of automobiles.It can absorb collision energy by collapsing itself and reduce the damage to drivers and cars caused by impact.However,there are problems in the design of crash box of automobiles on the market nowadays,such as excessive collision peak force and insufficient energy absorption,which can easily cause damage to important parts such as front longitudinal beam,engine and driver.Therefore,the research on optimal design of crash box has a good theoretical and practical significance for passive safety and collision energy absorbing structure.By comparing the crash standards and laws at home and abroad,this paper chooses RCAR(Research Council for Automobile Repairs)standard as the reference to establish the crash analysis model of crash box based on the theory of nonlinear finite element,completes the realization of low-speed crash test on simulation platform,and simplifies the model under the condition of guaranteeing the accuracy of solution,which greatly improves the efficiency of analysis.Select the appropriate material of crash box and its performance evaluation index to guide the design of crash box.The main work of this paper can be summarized as follows:(1)An optimized tapered and multi-cell crash box structure is established to enhance the specific energy absorption of crash box and better embody the concept of lightweight design.By analyzing the characteristics of traditional crash box and polygon crash box,groove crash box,multi-cell crash box and tapered crash box,a tapered and multi-cell crash box is built with tapered and multi-cell structure.The effect of wall thickness and taper on the performance of tapered and multi-cell crash box was analyzed and optimized by using response surface model.Compared with the original multi-cell crash box,the peak collision force of the optimized structure is reduced by 59.08% and the specific energy absorption is increased by 77.11%.(2)The machine learning method is used to predict,analyze and optimize the origami crash box.In view of the application and characteristics of origami structure in various industries,the simulation model of origami crash box is established,and the automatic modeling of origami crash box is realized by parametric modeling method.The influence of geometric parameters of origami crash box on its performance and collapse mode is analyzed by machine learning method.Then the structure is optimized by multi-objective optimization method.Finally,the origami crash box with good performance is obtained.The peak collision force of the optimized structure is 17.65% lower than that of the traditional octagonal crash box,and the total energy absorption and the specific energy absorption are increased in varying degrees.The analysis process of this research verifies the reliability of the application of machine learning method in engineering,and lays a foundation for the application of thin-walled energy absorption structure and machine learning method in engineering.