基于复杂工程约束的车身梁截面优化设计

Optimization Design for Auto-body Beam Section Based on Complex Engineering Constraints

通过对车身梁截面设计约束问题的研究,将车身薄壁梁截面形状优化设计问题和截面的材料、厚度等离散参数优化问题耦合起来。以工程设计中的可装配性和可制造性为设计约束,建立车身梁截面多目标优化方法。该方法以车身梁结构性能、成本、质量为目标,通过对梁截面形状进行独特的编码,实现以梁截面的形状、厚度、材料为设计变量的多目标优化模型,该模型采用NSGA-II遗传算法实现了多目标优化问题计算。基于该方法实现相应的软件模块并建立材料参数与厚度数据库。实例证明,该方法既可用于车身概念设计阶段确定满足设计目标且符合工程要求的梁截面形状参数,也适用于详细工程设计阶段对现有车身截面进行局部优化以增加车身刚度和减小部件质量。

Through the study of the automotive body beam cross-section optimization, the method couples the continuous optimization problem, such as cross-section shape, with the discrete variable optimization problems, such as types of section material and their thickness. With the assembly and manufacturability in the engineering design as design constraints, an automotive body thin-walled beam cross-section multi-objective optimization method is established. The method build a multi-objective optimization model with the vehicle body beam structure performance, cost, weight as design goals, the section shape, thickness, material as design variables by using a special coding way for the section shape. NSGA-II genetic algorithm is applied to solve the multi-objective optimization, and a material parameters and standard thickness database is built in the method. The case proves that this method not only can be used to quickly obtain the beam cross-sectional shape and material parameters, which meets the design goals and the requirements of engineering design in the conceptual design phase, but also can work in detailed engineering phase to optimize the local shape for the beam to improve the body stiffness while decreasing the body mass.