Multi-disciplinary And Multi-objective Lightweight Design Of Commercial Vehicle Cab Body In White

Cab is an important part of the whole vehicle.The lightweight of the cab structure plays an important role in the lightweight of the whole vehicle structure.In this paper,the cab of a heavy commercial vehicle is taken as the research object.Considering the performance of the cab,such as bending and torsional stiffness and low-order natural frequency,a multidisciplinary integration process is constructed to carry out the lightweight design of the cab structure.The main research contents of this paper are as follows:Modular modeling method is used to build the implicit parameterized model of cab.In order to verify the accuracy of the implicit parameterized model,the static stiffness performance and low-order natural frequency of the finite element model of the wheelhouse body-in-white were simulated and analyzed,and the test platform was built to compare the simulation analysis results with the test results.The results show that the relative errors of the stiffness performance and the natural frequency performance of the wheelhouse are less than 15%.The modeling accuracy of the parameterized model of the wheelhouse body-inwhite meets the actual engineering needs of enterprises.In order to solve the problem of reading modal data when the order jump of mode shape occurs in the process of experimental design and optimization,a mode tracking method based on the modal confidence criterion MAC is adopted to establish a mode tracking system,which can automatically recognize the mode shape and read the modal value.On this basis,a multidisciplinary integrated interactive optimization platform was built,and the optimal Latin hypercube experimental design method was selected to sample points,and the contribution degree of each design variable to the output response was obtained.In order to solve the problem of variable selection for multi-objective output responses,a variable selection method based on combinational weight-TOPSIS method was adopted to screen out 30 design variables with large comprehensive contribution from 126 implicit parameterized design variables.The response surface approximation model was constructed to replace the real simulation analysis model.Aiming at the problem of low fitting accuracy of the first-order bending mode,the mixed approximation model was used to deal with the residual of the response surface approximation model to improve the fitting accuracy of the approximation model.The anti-generation distance was used to verify the diversity and convergence of the NSGA-Ⅲ algorithm.Taking mass,torsional stiffness and first-order torsional mode as objectives,and bending stiffness and first-order torsional mode as constraints,the NSGA-Ⅲ algorithm was used to design and verify the multi-objective lightweight of the cab body in white.The results show that the torsional stiffness and torsional mode of the improved cab body in white model are increased by 10.48% and 9.16%,respectively.The weight decreased by 19.755 kg,and the better lightweight effect was achieved.