基于刚度与模态的某皮卡车车架优化设计

Optimization Design of Pick-up Truck′s Frame Based on Stiffness and Model

针对某皮卡车特定车速下的异常振动问题进行有限元建模分析,结合相关实车试验分析结果确定异常振动的原因。对比车架模态仿真与试验结果以验证有限元模型的精确度,进而对样车车架进行扭转与弯曲工况下的刚度分析、灵敏度分析。基于有限元分析结果,选取车架部分部件板厚为设计变量,车架低阶模态频率与刚度为约束,车架总质量最小化为目标对样车车架进行结构优化。优化结果表明:车架低阶模态避开了可能发生共振的频段,同时又实现了车架的刚度优化与轻量化设计。

Finite element analysis for abnormal vibration of a pick-up truck at specific speed is made,combined with vehicle tests, the cause of abnormal vibration is determined. The accuracy of finite element analysis is verified by comparing modal simulation with test results,then analysis of torsional stiffness,bending stiffness,sensitivity for the frame parts thickness can be made. According to the results of finite element analysis, the thickness of some frame parts is chosen as design variables,low order modal frequencies and stiffness as constraints,minimizing the mass of frame as an objective for the frame structure optimization. The optimization results show that lower modes of frame not only avoid resonant frequency, but also achieve frame stiffness optimization and light-weight design.