Performance Analysis And Optimization Of An MPV Door

As China’s "three-child" birth policy is gradually implemented,the requirements for car for family travel have changed.Families with more children have upgraded their demand for larger vehicles,and multi-purpose vehicles(MPV)with wider space and more comfortable seating have become the focus of attention.In the context of the major strategy of carbon peak and carbon neutrality propose to respond to global warming,lightweighting of automobiles have become a hot research topic in the transportation industry to improve energy utilization efficiency and reduce greenhouse gas emissions.Door is the key component of vehicle system,and its performance is related to the direct experience of users.In the current research on car door performance optimization,the problem of simultaneously optimizing multiple targets is often transformed into a single-target optimization problem through constraints and weighting,in order to obtain the optimal solution for a single target.Therefore,this thesis took the door of a certain MPV as the research object,established its finite element simulation model,and simulated and analyzed its comprehensive performance such as NVH,stiffness,strength,and durability.Then it is tested and verified.Finally,the thickness of each sheet metal component of the door was taken as the design variable,and the lowest door weight,the highest inner plate modal frequency,and the highest door frame stiffness were set as the optimization targets.The research content was as followed:(1)The finite element model of the door was established,including simplification model,mesh division,attribute assignment,definition of connection relationship,and mesh quality check,providing the finite element model foundation for subsequent analysis and optimization.(2)Through finite element analysis of the door,the modal,window frame stiffness,door frame stiffness,torsional stiffness,waistline stiffness,sagging,opening and closing durability,and dent resistance simulation results of the door were obtained,and a comprehensive analysis was carried out to obtain more comprehensive door strength,stiffness,durability,and NVH performance.The results showed that all performance indicators of the door meet enterprise requirements,and there was great potential for lightweight optimization.(3)The accuracy of the finite element simulation model was verified through experimental research on the door,and the modal,window frame stiffness,and torsional stiffness of the door were tested and compared with the corresponding finite element analysis results in Chapter 2.(4)Multi-objective optimization of the door was completed.Firstly,seven design variables that had a greater impact on door weight,modal and door frame stiffness were selected from the 17 thicknesses of various components of the door.Comparing the response surfaces constructed by LSR,MLSR,HK,and RBF fitting methods,the response surface with the best fitting effect was selected for the next multi-objective optimization.The lowest door weight,the highest inner plate modal frequency,and the lowest redundant door frame stiffness were set as the objective functions.By comparing the Pareto solution sets obtained by different optimization algorithms,the multi-objective genetic algorithm based on non-dominated sorting and reference points(NSGA-III)with better comprehensive performance was selected.After determining the optimal solution,the model parameters were modified,and the accuracy of the optimization results was verified by using finite element analysis to determine the final optimal solution.The results show that using the multi-objective optimization method based on non-dominated sorting and reference points can reduce the weight by 13.63% while the door frame stiffness and inner panel modal frequency are still up to the standard.Compared with traditional multi-objective optimization methods based on crowding distance mechanism,the solution set of this method has better uniformity and convergence,which is conducive to finding more optimal solutions.Therefore,this thesis focuses on the performance analysis and optimization of MPV doors,including the analysis of various comprehensive performance indicators such as NVH,stiffness,strength,and durability;multi-objective optimization research and comparative analysis with real vehicle verification.The results are reasonable and effective,establishing a comprehensive analysis and optimization method for the performance of MPV doors,which has certain engineering reference and application value.