Research On Light Weight Of Commercial Vehicle Door Structure Based On Multi Objective Optimization

In recent years, resource consumption and environmental pollution have put forward higher requirements for the development of the automobile industry, and the lightweight of automobile is one of effective ways to solve the above problems. Vehicle door is an important and relatively independent part of automobile. Due to its special performance, it is required to follow a certain scientific method to carry out lightweight research on vehicle door. Relying on the commercial vehicle development project of ChongQing ChangAn Automobile Co in this paper, the stiffness and the free modal of vehicle door with large size structure were optimized according to the performance requirements of stiffness,free modal, dent resistance and safety, and optimization results were verified by safety testing. The main research works of this paper are summarized as follows:1、First, the finite element model of left front door of commercial vehicle was built. The dent resistance of outer panel of the vehicle door was analyzed according to the regulations of a certain company, and the optimization schemes were proposed according to the analysis results. The use of the optimization schemes enabled outer panel of the vehicle door to meet the dent resistance of less than lmm deformation requirements of the enterprise.2、The stiffness conditions of vertical, corner of the window, upper and lower torsion and free modal conditions were established in accordance with the regulations after dent resistance optimization. Afterwards, the stiffness and free modal performance were judged by comparing with the internal standards of the enterprise. In addition, the experiments were carried out to verify stiffness and modal results of vehicle door.3、Based on the results of stiffness and free modal analysis, the main effect method was used to select optimal design variables, and test design of the structure of vehicle door was carried out by Hammersley sampling to fit the two order polynomial response surface models with high precision for stiffness, free modal and quality response. Then, with the performance index of a company as the constraint, and the minimum quality as the goal. The above approximate models were optimized by the sequential two programming method. Finally, the experiments were carried out to verify validity and reliability of optimization results of dent resistance, stiffness and modal of vehicle door.4、This paper described the contact theory of LS-dyna in the collision process and the European NCAP lateral rigid column collision regulations, and established the rigid cylinder collision model of vehicle door. The side passive safety of commercial vehicle door was evaluated by comparing the intrusion velocity and intrusion displacement of the reference points with enterprise standards.