| With the development of automobile technology and the improvement of people’s demand,power sliding doors(PSD)gradually appear in multi-purpose vehicle(MPV)models,improving their practicality and comfort.However,due to immature technology development,the durability of the transmission mechanism of PSD in some domestic MPV models is low and cannot meet China’s automotive industry standards;under the pressure of environment and energy,various technical routes,plans and policies on automotive development released by the state and industry have included automotive lightweight as an important content,and automotive lightweight will become one of the core technologies of the automotive industry.MPV is an important component in the whole vehicle,its lightweight level will directly affect the weight and lightweight level of the whole vehicle.In order to solve the above problems,this paper takes the PSD of an MPV of an enterprise as the research object and carries out structural improvement and lightweight design.The specific research contents and conclusions of this paper are as follows:(1)In order to solve the problems of short life and large space occupation of the rope transmission mechanism in the PSD system,we proposed to improve it into a rack and pinion transmission mechanism and redesigned the lower walking wheel arm to form the PSD-1.The PSD-1 multi-body dynamics model was established in Adams and the smoothness analysis and improvement were carried out.The fatigue test was conducted on the PSD-1 system with rack and pinion transmission mechanism installed in the whole vehicle,and the results showed that the mechanism is durable and has a life of more than100,000 cycles,which meets the enterprise standard.(2)The finite element model of PSD and PSD-1 was finally established through geometric cleaning,mesh division,connection relationship establishment,material attribute ascription and other operations.Through the stiffness simulation analysis and experimental comparison of PSD,the simulation error is 2.8%,which proves the accuracy of the finite element model of PSD and the reliability of the modeling method in this paper,and provides a basis for further analysis and optimization of the performance of PSD and PSD-1.(3)The finite element simulation analysis of the modal,torsional stiffness,window line stiffness,sagging stiffness and window frame stiffness of PSD-1 and PSD-1 is carried out.The results show that the modal frequency and stiffness of PSD-1 are slightly smaller than that of PSD-1,but it still meets the requirements of enterprises and has a certain margin,which can be followed by lightweight design.(4)Sensitivity analysis and relative sensitivity analysis were performed on the thickness variables of 19 components of PSD-1 regarding stiffness and modal performance,and the thickness of 11 components were selected as the optimized design variables.Finally,the maximum shape variable under each stiffness is taken as the optimization constraint,and the two objectives of minimum mass and maximum first-order modal frequency are taken as the optimization objectives to establish the multi-objective lightweight mathematical model of PSD-1.(5)150 fitted sample points were collected using Hammersley series sampling and 10 test sample points were collected using Latin hypercube sampling,respectively.Then,polynomial response surface model was used to fit the PSD-1 mass and radial basis function model to fit the relationship between PSD-1 stiffness and mode and design variables,and the accuracy analysis proved that the accuracy of the established approximate model was high and met the requirements of engineering optimization design.Finally,the multi-objective genetic algorithm was used to solve the multi-objective lightweighting mathematical model,and the optimized PSD-2 mass was reduced by 2.461 kg,which was 11.22% lighter,and the first-order modal frequency was increased by 1.628 Hz,with an optimization rate of 5.61%,and the optimization effect was obvious. |
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