基于拓扑优化的柴油机下曲轴箱改进设计

Improvement Design of Lower Crankcase of Diesel Engine Based on Topology Optimization

针对某型大功率军用柴油机,运用特征化实体建模技术,利用HyperWorks-Optistruct软件平台,开展了基于拓扑优化的该柴油机下曲轴箱结构改进设计。在优化设计中,以提高下曲轴箱结构刚度为目的,建立了以结构质量最轻为优化目标、下曲轴箱固有频率提高20%为约束函数的拓扑优化设计模型。优化后的下曲轴箱质量有了明显降低,前5阶固有频率也有了不同程度的提高,实现了移频和减质量的结构改进目标,并给出了曲轴箱结构材料的最优分布图。这为有效提高下曲轴箱的结构刚度,进而改善柴油机整机的结构辐射噪声,奠定了基础。

In this paper,Taking a certain type of high-power military diesel engine as a object,improvement design of the lower crankcase of the diesel engine based on topology optimization was carried out by using the feature-based solid modeling techniques and platform of HyperWorks-Optistruct software.In order to increase structural stiffness of the lower crankcase,topology optimization design model was established by setting lightest structure weight as a target and 20%-increased natural frequencies of the crankcase as a constraint function.After optimization,the crankcase＇ weight is significantly reduced and first five order natural frequencies are also increased to various degrees.The goals of frequency shift and structural weight reduction are achieved,and optimal distribution of the structural material of the crankcase is obtained,which lay a foundation for effectively improving the structural rigidity and radiated noise of diesel engine.