基于模态分析的船用柴油机油底壳结构优化

Structure Optimization for Oil Sump of Marine Diesel Engine Based on Modal Analysis

以某船用柴油机油底壳为研究对象,采用有限模态分析方法,研究单因素结构变化对比分析不同结构布置及参数对动态特性的影响,为结构优化提供参考,证明并利用了模态振型的正交性,完成了油底壳的优化设计。针对优化后油底壳开展了有限元与试验模态分析方法,相应模态振型的模态频率偏差较小,装机状态油底壳具有良好的动态特性,模态频率能完全避开柴油机最高转速的激励频率,避免了发动机运行时共振的可能。

This paper applies FEM modal analysis method on the oil sump of a Marine diesel engine to study the influence of different structure arrangement and parameters on the dynamic characteristics of single factor structure,provides reference for structure optimization,and demonstrates the orthogonality of modal modes,with which the optimization of the oil sump was completed.The FEM and experimental modal analysis are carried out for the optimized oil sump,the modal frequency deviation of the corresponding modal mode is small.The oil sump in the installed state has good dynamic characteristics.The modal frequency can completely avoid the excitation frequency of the diesel engine and avoid the possibility of resonance.