某轻型商用车车架多性能约束下的轻量化研究

Research on Lightweight of a Light Commercial Vehicle Frame Under Multi Performance Constraints

为了提高某商用车可靠性能并降低生产成本,采用基于代理模型的优化方法对其车架进行面向静动态性能的轻量化设计。基于Hyperworks建立了车架有限元模型并进行静动态性能有限元分析,通过车架灵敏度分析,确定了包括纵梁在内的17个关键零件。进一步以关键零件部件厚度为设计变量,考虑静动态性能约束,结合径向基函数(RBF)代理模型构建了车架轻量化优化设计模型,应用多目标遗传算法(NSGA-Ⅱ)协同最小距离法的确定了各点到原点距离的最优解集。优化后车架仿真分析表明:车架重量降低5.6kg,车架静动态性能中一阶模态频率提高1.45%,而弯曲和扭转刚度下降4%以内,同时优化后车架的可靠性被疲劳寿命仿真试验验证反馈。

In order to improve the reliability of a commercial vehicle and reduce the production cost,the optimization method based on agent model is adopted to carry out the lightweight design of its frame for static and dynamic performance.Based on Hyperworks,the finite element model of the frame is established and the static and dynamic performance is analyzed.Through the sensitivity analysis of the frame,17 key parts including the longitudinal beam are determined.Taking the thickness of key parts as the design variable,considering the static and dynamic performance constraints,combined with the radial basis function(RBF)proxy model,the lightweight optimization design model of the frame is constructed.The optimal solution set of the distance from each point to the origin is determined by using the multi-objective genetic algorithm(NSGA-Ⅱ)and the cooperative minimum distance method.The simulation analysis of the optimized frame shows that the weight of the frame is reduced by 5.6kg,the firstorder modal frequency in the static and dynamic performance of the frame is increased by 1.45%,while the bending and torsional stiffness are reduced by less than 4%.At the same time,the reliability of the optimized frame is verified and fed back by the fatigue life simulation test.