【摘要】 鉴于概念设计在车身设计中具有重要地位,提出了车身结构概念设计流程,构建了车身简化空间框架模型,采用半刚性梁和传递矩阵法建立车身刚度链模型。求解仅约束静动态性能的优化模型,分析优化后梁单元的应变能和应变能密度。为协调优化多工况下材料的利用和分配,引入变异系数作为约束指标。该设计方法,考虑了应变能因素的车身半刚性梁刚度链,以车身轻量化为目标,以弯扭刚度、固有频率和各工况应变能密度的均匀程度为约束条件,运用遗传算法,优化主断面参数。与标杆车仿真结果进行了对比。结果表明:应变能密度均匀化可以提高车身材料的效用,改善车身性能。因此,该设计方法具有可行性。更多还原

【Abstract】 A conceptual design process of vehicle body structure was presented with a simplified space frame model being established since conceptual design is important for vehicle body design. A stiffness chain model of vehicle body was established by using a semi-rigid beam and transfer matrix method. The strain energy and strain energy density of the optimized beam element were analyzed by solving the optimization model with constrains only including the static and dynamic performance. The coefficient of variation was introduced as the constraint index to coordinate and optimize the utilization and distribution of materials under multiple working conditions. The design method considered the vehicle body semi-rigid beam stiffness chain and the strain energy factor. Body lightweight was taken as the objective function, and the vehicle body static stiffness, natural frequency, and the uniformity of the strain energy density at each working condition were taken as constraints for optimization. The genetic algorithm was used to solve the optimization problems and determine the main crosssection parameters. The results of the design method were compared with the simulation results of benchmark vehicle. The results show that the uniformity of strain energy density can improve the utility of the material and the performance of the vehicle body. Therefore, the design method is feasible.更多还原