Lightweight Design And Spot Weld Layout Topology Optimization Of Minicar Door

The vehicle door as the important panel of the car body provides a closed space for crews.The basic performance of the door is directly related to the overall vehicle safety,durability and comfort. At the same time, reducing the vehicle quality is an important means to reduce the fuel consumption, the significance of lightweight door is very important to reduce the pollution of the environment and energy using.Therefore, in this paper, the static and dynamic characteristics of the minicar door and lightweight research were carried on the base of size optimization, sensitivity analysis and topology optimization. The main research contents are as follows:(1) The finite element model of the minicar door was built and the performances of the door was analyzedFirstly, the finite element model of the door was established, and then the free modal and the door window frame stress condition, sinking condition, torsion condition,finite element stiffness and strength properties of the door under those conditions of analysis. According to the analysis results evaluated the initial performance of the door.All of the above provided reference and standard for the lightweight design and performance optimization of the following steps.(2) The lightweight design of the door based on sensitivity analysis and size optimizationIn order to maintain the shape and structural characteristics of the door, just the thickness of the door’s panels were optimized in this paper. Firstly, 23 parts of the door were chosen as the design variables to do the sensitivity analysis. From this got the performance sensitivity and relative sensitivity. Then, the optimal variables were determined by the results of relative sensitivity with the door stiffness and first-order natural frequency as constraints and the size optimization was carried on the panels of the door. The final optimization results showed that the quality of the door was reduced by 3%, at the same time to verify the performance of the optimized door found that the door had a small increase in performance compared with the initial performance.(3) Spot weld layout optimization based on topology optimizationFirst of all, the optimization model was established.The constraint conditions were the three different spot weld volume limit on the minicar door and the objective function was the weighted strain energy minimization of the door. The number of spot weld preliminary optimization plan was determined by comparing the results of threeoptimization schemes. On the basis of this, the spot weld model was encrypted, using topology optimization method to optimize the layout of the spot weld. Finally,on the premise of not increasing the number of spot weld the performance of the door were increased.In this paper, through the size optimization of the panels and topology optimization of the spot welds achieved the loss of quality and the improving of the performance.After the optimization the door’s quality is reduced to 17.75 kg, about 3% less than the original quality. And the number of spot weld is reduced to 94, a decrease of approximately 13% compared with the original model. On this basis, the performances of the door are promoted. The entire design process has reference significance to lightweight design and the spot weld optimization of vehicle.