某皮卡车门布置设计及多目标轻量化优化设计研究

发布时间：2019-03-22 06:06

【摘要】：由于环境污染和资源枯竭的问题日益加重,在汽车领域进行轻量化研究成为了汽车开发的重要课题。本文通过对某款皮卡车型的车门结构进行布置和设计,以此车门为研究对象建立车门扭转刚度、下垂刚度、侧向弯曲刚度、模态频率和抗凹性的有限元模型,并对车门的各项性能进行分析与评价。根据车门结构的轻量化需求,对车门进行多目标优化设计研究,且考虑到不确定因素的干扰,在多目标优化的基础上进行稳健性的检验与分析,使车门不仅达到轻量化目标,还具备良好的稳健性,具体研究工作与成果如下:(1)在车门的布置阶段,通过车门中各个主断面图来完成车门铰链、玻璃升降器、限位器、锁体、内外手柄和防撞梁的布置。在车门的设计阶段,根据车门的布置内容,对车门内各个零件进行设计,其中包括对叉臂式玻璃升降器的平顺性、玻璃升降器电机的快速选型、限位器主臂形状和密封条进行深入研究。在车门完成布置和设计后,利用CATIA的DMU模块,并根据车门实际运动状况和约束自由度的分析建立车门运动仿真机构,检测关键零件之间的最小运动间隙,以保证车门布置和设计的合理性。(2)将车门模型导入HyperMesh中进行几何清理和网格划分,在检查和控制车门网格质量以后,按照焊接、螺栓和涂胶的连接方式,将各个零件的有限元模型进行连接,并定义结构件的材料属性,建立车门扭转刚度、下垂刚度、侧向弯曲刚度、模态频率和抗凹性有限元模型。在车门有限元模型的基础上,运用Optistruct计算车门各项性能的仿真数值,并将其与企业标准相对比,各项性能都符合设计要求,但仍然存在较大的轻量化空间。(3)首先,根据车门有限元分析结果和参数试验设计,筛选出贡献量较大的8个设计变量进行设计样本的采样。其次,以采样数据和响应面近似模型原理为依据,构建车门质量、刚度、抗凹性和模态响应面近似模型,并检验近似模型的精度。最后,以筛选的车门零件为设计变量,以车门扭转刚度、下垂刚度、侧向弯曲刚度和抗凹性满足要求为约束条件,以车门质量最小和车门前三阶模态频率最大为目标函数,构建车门多目标优化的近似模型,并利用NSGA-Ⅱ遗传算法进行求解,获得车门质量与第一阶模态频率的Pareto非劣解的解集,从中挑选出满足优化条件的最优解。优化后的车门性能不仅满足企业标准,还实现了第一阶模态频率提高和车门轻量化的目标,其中车门的质量为17.19kg,减轻了0.97kg,减轻的幅度达到5.34%,而车门第一阶模态频率为34.59Hz,提高了0.27Hz。通过蒙特卡洛模拟中的描述性抽样技术对多目标优化后的车门质量水平和可靠度进行分析,获得各个输出响应的Sigma质量水平和可靠度分别为8Sigma和1,则此多目标优化后的车门已经具备良好的稳健性,无需进行6Sigma稳健性优化。
[Abstract]:Due to the increasingly serious problems of environmental pollution and resource depletion, lightweight research in the automotive field has become an important subject of automobile development. In this paper, the structure of a pickup car door is arranged and designed, and the finite element models of the torsional stiffness, drooping stiffness, lateral bending stiffness, modal frequency and concave resistance of the door are established. The performance of the door is analyzed and evaluated. According to the lightweight demand of the door structure, the multi-objective optimization design of the door is studied. Considering the disturbance of the uncertain factors, the robustness of the door is tested and analyzed on the basis of the multi-objective optimization, so that the door can not only achieve the goal of lightweight. Also has good robustness, the specific research work and achievements are as follows: (1) in the door layout stage, through each main section diagram of the door to complete the door hinge, glass elevator, position limiter, lock body. Layout of inner and outer handles and anti-collision beams. In the design phase of the door, according to the layout of the door, the various parts of the door are designed, including the smoothness of the fork-arm glass elevator and the quick selection of the glass elevator motor. The shape of the main arm of the limiter and the sealing strip are studied in depth. After the car door is arranged and designed, the DMU module of CATIA is used, and the simulation mechanism of the door motion is established according to the analysis of the actual motion condition and the constraint degree of freedom of the door, and the minimum motion gap between the key parts is detected. To ensure the rationality of the car door layout and design. (2) introduce the door model into the HyperMesh for geometric cleaning and mesh division. After checking and controlling the quality of the door mesh, according to the welding, bolt and glue-coated connection mode, The finite element model of each part is connected, and the material properties of the structural member are defined. The torsional stiffness, sag stiffness, lateral bending stiffness, modal frequency and concave resistance of the door are established. On the basis of the finite element model of the door, the simulation value of the performance of the door is calculated by Optistruct, and compared with the enterprise standard, all the performances accord with the design requirements, but there is still a large lightweight space. (3) first of all, there is a lot of light space for the performance of the car door. According to the results of the finite element analysis of the door and the experimental design of the parameters, eight design variables with large contribution were selected to sample the design samples. Secondly, based on the sampling data and the principle of response surface approximation model, an approximate model of door mass, stiffness, concave resistance and modal response surface is constructed, and the accuracy of the approximate model is tested. Finally, taking the selected door parts as the design variables, taking the door torsional stiffness, droop stiffness, lateral bending stiffness and concave resistance as the constraint conditions, the objective function is the minimum quality of the door and the maximum of the first third-order modal frequency of the door. The approximate model of door multi-objective optimization is constructed and solved by NSGA- 鈪，

本文编号：2445317