Multi-Material Lightweight Automobile Door Structure Optimization And Solder Joint Layout Optimization

With the continuous development of the automobile industry,people have put forward higher requirements for the performance of automobiles,not only in the driving performance of the vehicles,but also in the environmental protection and economy of the vehicles.As an important part of a car,the performance of the door is closely related to the comfort and safety of the car.Therefore,the door is an important aspect of vehicle research and design.Lightweight,as a key direction of the current automotive industry towards a green development path,is also one of the hot spots in automotive design research.This article focuses on the performance of the car door and its lightweight.It mainly uses the multi-attribute decision-making method based on information entropy and sensitivity analysis to replace the original materials of some parts of the car door,and use new lightweight materials to achieve the light weight of the car door.,And further optimize the design of the door after replacing the material.It can be divided into the following parts:(1)The establishment and performance analysis of the door model;First,establish the finite element model of the door based on the three-dimensional model.Secondly,perform the analysis of the stiffness performance under the droop condition,the upper torsion condition,the downward torsion condition,the lateral bending condition,the inner and outer plate waistline conditions on the model.And free modal analysis,and use these parameters as constraints for subsequent optimization.(2)Selection and replacement of door parts/materials;In order to realize the lightweight design of the door,firstly use the thickness of each part of the door as a design variable to analyze the door quality and modal frequency sensitivity,and obtain some parts that have a greater influence on the door quality and first-order modal sensitivity(finally select 12 Parts)on this basis to replace the materials of these parts.Then,use the multi-attribute decision-making theory to select suitable lightweight materials,and after determining the material selection,replace the selected parts with equal quality materials.Finally,a simulation analysis of the door performance after the replacement of materials found that compared with the original door,the stiffness performance and modal frequency of the optimized door under various working conditions have been improved.(3)Multi-objective optimization analysis of component thickness;First,the Hammersley test design is carried out based on the parts selected in the previous chapter,and the LHD test design method is used to verify the established approximate model.The design variable is selected as the thickness of the component,the maximum displacement deformation under each working condition is the constraint condition,and the minimum mass and the maximum first-order modal frequency are used as the objective function.The results show that the weight of the door is reduced by 7.8% while the frequency of the first-order mode is also increased.(4)Optimization of the layout of the door solder joints;First,establish constraints.Including two aspects,one is the upper limit of the solder joint unit volume is 0.8,0.85,0.9,these three different percentages,and the second is the third-order modal frequency in front of the car door.With the minimum weighted strain energy as the optimization goal,the solder joint volume is optimized,and the solder joints of the model are encrypted.The topology optimization method is used to optimize the layout of the solder joints.The final optimization results show that: without changing the number of solder joints Under the circumstances,the performance of the door can be improved to a certain extent by optimizing the layout of the solder joints.Finally,after the material replacement of the door components and the optimization of the solder joint layout,compared with the original door model,the optimized door model reduced the weight by 7.8%,and the key evaluation indicators of the door stiffness performance and modal vibration performance were improved.