Study On The Anti-collision Structure Optimization In High-speed Crashes

In recent years, with the rapid development of automobile industry, automobile safety has attracted more and more attention.In the high speed crashes, based on the occupants' safety, the reasonable transfer and absorption of the collision energy will be considered in the bumper system design.The optimal parameters of automobile parts mainly include the shape parameters, material parameters, geometric parameters and so on, and these parameters have different degree of influence on collision crashworthiness.There are two phenomena in existing researches,one is that the bumper crashworthiness and lightweight research only based on low speed crashes,the high speed crashes are not taken into account;another is that there is only a single property(material,shape,thickness) changed in the bumper crashworthiness and lightweight research, this single changed research might miss the better optimization structure design.This paper, proposes a new optimization algorithm about the composite structure of the bumper beam based on Fruit Flies Optimization Algorithm,combines the theory of experimental design, computing simulation and statistical methods.Then,the bumper beam composite structure is optimized in this paper.In high speed frontal crashes, considering the occupant safety, the whole paper studied the crashwothiness of the bumper beam by using dynamic explicit finite element simulation method, and numerically simulated the bumper system.First of all,according to China-New Car Assessment Program(C-NCAP),this study simplify the bumper beam structure on the basis of the Finite Element model(FE model) of the frontal crash, and verify the vehicle stability and feasibility of the FE model.Then, it select appropriate design parameters of composite structure by using the orthogonal experimental design method. Third, the layer thicknesses were regarded as design variables, the lower value of the human head injuries was regarded as optimization target,the mass and relative cost of the bumper beam were regarded as constraint function for the following crashworthiness optimization design, it makes polynomial response surface model by using optimal Latin Square Design(LSD) to choose sample points. Finally, this paper establishes the numerical agent model,which has relationship with optimization objective,constraint function and design variables. And it gets the optimal solution by applying FOA.The design of a new type of composite structure of bumper beam based on FOA,the research results show, that not only improved the crashworthiness of bumper beam in frontal crashes, but also reduced the value of human head injuries. This new design method improved the occupant safety and light the weight of bumper system. The method in this paper provides a reference for the optimization design of crashworthiness and lightweight.