基于动态特性分析的油底壳结构优化

Structural Optimization of Oil Pan Based on Modal Analysis

摘要: 通过有限元法对目标柴油机油底壳进行模态分析，掌握其结构动态特性，确保油底壳的固有频率避开柴油机的激励频率。计及油底壳内部油液质量的影响，采用声固耦合法评估了带油液的油底壳的振动特性。结果显示内部油液质量会导致结构固有频率明显降低，一阶模态频率降幅达41.5%，证明在油底壳设计分析中内部油液的重量不能忽视。本文提出五种优化方案对油底壳进行优化设计，通过油底壳湿模态计算结果对比，证明增加筋板为最佳优化方案，并对最优方案模型进行振动响应计算，验证优化后油底壳的振动响应比原模型有大幅降低。

Abstract: Modal analysis of oil pan of diesel engine is carried out by finite element method to ensure that the frequencies are away from the excitation frequency of diesel engine. The vibration characteristics of the oil pan with oil were evaluated by using the sound-structure coupling method, considering the influence of the oil inside the oil pan under working condition. The results show that the fre-quencies of the oil pan with oil inside are significantly lower than those of the dry mode, and the frequency of the first mode is reduced by 41.5%, which indicates that the oil cannot be ignored in the design and analysis. In this paper, five structural optimization schemes are proposed to opti-mize the oil pan. By comparing the results of dynamic characteristics analysis, it is proved that the reinforcement plate is the best optimization scheme. The vibration response calculation of the op-timization model is carried out to verify that the vibration response of the oil pan after optimization is significantly reduced compared with the original model.