Research On The Application Of Tailor Rolled Blank In Vehicle Crashworthiness

In the face of the increasing car ownership and increasingly severe environmental pollution in China,vehicle lightweight technology has become a new green development trend to achieve effective energy saving and emission reduction.However,in the process of vehicle weight reduction,the vehicle crash safety must be considered,so it is particularly important to consider the vehicle body lightweight and crashworthiness design simultaneously.The research shows that tailor rolled blank(TRB)has great potential in improving vehicle crashworthiness and it is an effective way to solve the above problems.At the same time,the application of TRB structure in vehicle crashworthiness and lightweight design has high engineering research value.In order to further explore the role of TRB structure in vehicle crashworthiness,this thesis first introduces it into the improved design of a pure electric vehicle front-end structure,and combines the finite element analysis and numerical optimization method to systematically optimize the structural parameters of TRB,so as to improve the crashworthiness of the whole vehicle.The main content is listed as follows:(1)To study the impact of the TRB structure on vehicle crashworthiness,the finite element models of vehicle front impact and TRB front-end structures are constructed and verified.First of all,based on the full-frontal crash condition of China-New Car Assessment Program(C-NCAP),the finite element simulation model of whole vehicle is established,and compared with the physical experiment,the validity of the model is verified.Secondly,based on the dynamic impact test,a TRB finite element simulation model of typical hat-shape beam is established,and the accuracy of the model is verified by comparing with the experimental data;then the TRB finite element models of the key energy absorbing parts of vehicle are constructed by the verified method.Finally,the full-frontal impact simulations of two different front-end models are carried out to compare and analyze the crashworthiness performance,so as to provide reference for the subsequent optimization.(2)To solve the computational efficiency of the finite element model,the hybrid kernel function support vector regression(HKF-SVR)approximate model is constructed based on the DOE sample points.At the same time,in order to better fit the highly nonlinear mathematical relationship and improve the accuracy of the approximate model,particle swarm optimization(PSO)algorithm is used to optimize the kernel function parameters of the approximate model,and the results show that the optimized approximate model has higher fitting accuracy.(3)To further improve the crashworthiness of the whole vehicle,the geometric parameters of TRB front-end structures are optimized.In the process of optimization,the parameters are optimized with the combination of design of experiment,improved HKF-SVR surrogate model and multi-objective particle swarm optimization algorithm to improve vehicle crashworthiness and realize the lightweight of the structure.In addition,the reliability of the system is optimized based on the deterministic optimization results.The final results show that the lightweight rate of the optimized TRB front-end structures is up to 11.5%,the crashworthiness and reliability of the whole vehicle have also been significantly improved.