大型自卸车车架静动态性能拓扑优化研究

Static and dynamic performance topology optimization of large dump truck frame

为使大型矿用自卸车车架的静动态性能同时得到提升,采用惯性释放法对大型矿用自卸车车架进行了有限元分析,并在此基础上进行了拓扑优化。将多工况下的平均柔度和前6阶弹性模态平均特征值通过一个权值进行组合成为多目标函数,约束车架体积,以单元密度作为设计变量,试算出6种不同权值下的车架拓扑结构。通过理想点法构造的评价函数,挑出一个使多目标函数取得理想解的权值,最终得到一个承载能力与动力学特性相匹配的最优化车架拓扑结构。优化后的新车架质量减少了1 371 kg,刚度提高了30%,第一阶弹性模态固有频率由原来的4.93 Hz提高到5.90 Hz,避开了路面激励频率范围,最大应力在多种工况下降低10%。研究表明该拓扑优化方法可以在减轻结构质量的同时,改善结构的承载能力和抗振动性能。

In order to improve the static and dynamic performance of large dump truck frame, iner-tial relief of finite element method was used to analyze a large dump truck frame. A weighted multi-objective function was conducted from the average flexibilities under several working conditions and the average eigenvalues of 6 modals. With constrained frame volume and element density as design variables, 6 kinds of different topological structures were obtained by using 6 different weighted fac-tors. Then the evaluation function was established through ideal point method and the right weighted factor was found to fit the multi-objective function. Finally, the optimized structure meets both strength and vibration requirements. After optimization, the mass of new frame decreased by 1 371 kilograms , and the stiffness increased by 30%. The first elastic mode natural frequency of optimized vehicle frame increased from 4.93 Hz to 5.90 Hz. The frequency of the frame avoided the road exci-tation frequency range, and the maximum stress reduced by 10% under a variety of conditions. The research shows that this topology optimization method can reduce the weight of structure, and im-prove the loading ability and vibration resistance performances.