考虑载荷不确定性的转向节结构优化研究

Structural optimization of knuckle under load uncertainty considerations

针对铝合金转向节几何形状复杂、承受随机载荷、工况恶劣、安全性要求苛刻而导致的轻量化设计难度大等问题,对转向节的结构优化与设计方法进行了研究。建立了双叉臂悬架的多体动力学模型,对转向节典型工况下的载荷进行了提取;开展了转向节的有限元模拟分析,采用拓扑优化的方法对转向节进行了减重设计;基于拓扑优化结果,利用区间不确定性稳健优化方法对转向节进行了二次优化,在考虑转向节随机载荷的基础上提高了优化结果的稳健性;设计了双层嵌套优化模型并进行了迭代计算;采用无重复饱和析因设计方法以提高二次优化过程的效率,减少了试验次数。研究结果表明:在降低最大应力值的基础上实现了铝合金转向节的轻量化,重量减轻比达7%,且在耐久性试验条件下转向节性能符合技术要求。

Aiming at the problems of light weight design difficulty caused by complex geometric shape of automotive aluminum alloy knuckles,bearing random loads,harsh working conditions,and strict safety requirements,the structure optimization and design methods of the knuckle were investigated.The multi-body dynamic model of the double-wishbone suspension was established to get the load of the steering knuckle under typical working conditions.On account of the finite element simulation analysis of steering knuckle,the method of topology optimization to weight reduction design of steering knuckle was adopted.Based on the topological optimization results,the method of interval uncertainty robust optimization was used to perform the quadratic optimization of the steering knuckle,and the robustness of the optimization results was improved by considering the random load of the steering knuckle.A double-layer nesting optimization model was designed for iterative calculation.On the other hand,the method of non-repetition saturation factorial design was used to improve the efficiency of the quadratic optimization process and reduce the number of tests.The results indicate that the aluminum alloy steering knuckle can be lightweight and the weight reduction ratio can reach 7%on the basis of reducing the maximum stress value,and the performance of the steering knuckle can meet the technical requirements under the durability test.