考虑多缸静动态特性的柴油机缸体拓扑优化

Topology optimization of internal combustion engine cylinder by considering static and dynamic characteristics of multi-cylinder

针对极限单工况拓扑优化结果无法保证多缸缸体在其他工况下的力学性能问题,基于层次分析法,提出一种综合考虑多缸静动态特性的缸体多目标拓扑优化方法。在分析缸体静态特性、模态的基础上,确定缸体的最恶劣工况及各工况下缸体的拓扑优化空间;考虑缸体的静态多工况刚度和动态多阶固有频率,构建包含12个权重因子的缸体拓扑优化多层次结构模型,利用折衷规划法定义兼顾缸体静动态特性的综合评价函数,并通过层次分析确定各权重因子,从而得到兼顾静态多工况刚度目标和动态多阶固有频率目标的拓扑优化数学模型。仿真结果表明,优化后的缸体拓扑结构更加合理,缸体质量减轻5.22%,静动态特性得到不同程度的改善。

The topological optimization results for the limit single operating conditions cannot guarantee the mechanical performance of the multi-cylinder under other working conditions.Based on the analytic hierarchy process,a multi-objective topology optimization method based on the multi-cylinder static and dynamic characteristics is proposed.On the basis of analyzing the static characteristics and modal of the cylinder,the worst working condition of the cylinder and the topological optimization space of the cylinder under various working conditions are determined.Considering the static multi-condition stiffness and dynamic multi-order natural frequency of the cylinder,the construction is carried out.A multi-level structural model of cylinder topology optimization with 12 weighting factors is used to define the comprehensive evaluation function by considering the static and dynamic characteristics of the cylinder block using the compromise planning method.The weighting factors are determined by the analytic hierarchy process to obtain the static multi-condition stiffness target and a mathematical model of topology optimization for dynamic multi-order natural frequency targets.The study results show that the optimized cylinder topology is more reasonable,the cylinder mass is reduced by 5.22%,and the static and dynamic characteristics are improved.