Thin-wall Structure Optimization Method Based On Reanalysis

In the process of automobile research and development,the design of automobile products is particularly critical.In terms of body design,body-in-white models usually consist of thin-walled beams whose structure determines the performance of the entire body.In addition,the structure of the thin siding also has a significant effect on the stiffness and frequency of the body frame.Therefore,it is necessary to optimize the thin-wall structure to improve the performance of the automobile structure.In the traditional body structure design,the complete simulation analysis is needed every time the design parameters are changed,which will reduce the computational efficiency.Reanalysis can be used to analyze the initial structure and quickly calculate the modified structure,so as to avoid the complete analysis and solution of similar structures for many times and improve the computational efficiency.In order to solve the problem of low efficiency in thin-wall structure optimization design,this paper uses reanalysis method instead of finite element analysis to quickly analyze the modified structure.The main research contents are as follows:(1)The reanalysis theory based on finite element method and the reanalysis method for static stiffness and dynamic stiffness are introduced,which provides the basis for the reanalysis method for thin-walled body structures.Finally,the static stiffness analysis and modal analysis of the perforated plate are carried out to provide a basis for the subsequent thin-wall structure optimization design.(2)According to the basic theory of thin-wall structure of body,including the basic theory of thin-wall beam structure and thin-wall panel structure,the reanalysis program for thin-wall structure of body is written,and the static stiffness analysis and modal analysis of thin-wall structure are carried out respectively.In the last example,finite element analysis is compared with reanalysis method to verify the accuracy and efficiency of the latter.(3)The differential evolution algorithm is introduced to optimize the thin-wall structure of the car body.The influence of mutation strategy and control parameters of differential evolution algorithm on searching ability and convergence rate of the algorithm is introduced in detail.In addition,the search ability and the convergence speed of differential evolution algorithm are improved by changing the mutation operator.In order to improve the computational efficiency of the algorithm,the reanalysis method is introduced to replace the complete finite element method.By comparing the convergence rate and operation results of the algorithm based on reanalysis and finite element method in three numerical examples,it is confirmed that the proposed algorithm can improve the optimization design efficiency of thin-wall structure.