Structural Performance Analysis And Reliability Optimum Design Of A SUV Body-in-white

The body-in-white is an important part of the whole vehicle.The structure performance of the body-in-white directly affects the comfort,safety and durability of the vehicle.The optimization of body-in-white structure needs to reduce the body weight based on ensuring its performance,improving its lightweight level.In the traditional optimization design of body-in-white structure,the influence of uncertainty of design variables on the optimization results is often neglected,which may lead to optimization failure.Therefore,the uncertainty of design variables should be fully considered in the optimization design process of the body-in-white structure.In this paper,the reliability optimization design method is used to optimize the body-in-white structure.Firstly,the finite element model of a load-bearing SUV body-in-white is established.On this basis,the low-order modal analysis of the body-in-white is carried out,and compared with the experimental data.Then,the stiffness and strength simulation analysis is carried out.Secondly,thickness of 27 components was selected as design variable by relative sensitivity analysis method,and the Optimal Latin hypercube sampling is used to design the experiment.The appropriate approximate model is selected to fit the relationship between the five output responses of the body-in-white and the design variables,the five output responses are total mass,first-order bending mode,first-order torsion mode,bending stiffness and torsion stiffness.Thirdly,according to the analysis results of the structure performance of the body-in-white,the total mass and the first-order torsional mode are selected as the optimization objectives,and the first-order bending mode,bending stiffness and torsional stiffness are selected as constraints.The deterministic optimization design of the body-in-white structure is carried out by using the non-dominated sorting genetic algorithm-II(NSGA-II).Finally,on the basis of deterministic optimization design,considering the influence of uncertainty of design variables on the optimization results,the reliability optimization design of the body-in-white structure is carried out,and the reliability optimization scheme is verified by simulation.The results show that the weight of the body-in-white is reduced,the modal performance is improved,the stiffness and strength performance meets the design requirements,and the reliability of the system is greatly improved.