基于模态相关性和模型修改的发动机整机模态分析

Modal Analysis of Engine Structure Based on the Modal Correlation and Model Modification

建立了发动机实体和有限元模型,介绍了计算模态分析和模态相关性分析的一般方法与理论.对某发动机整机进行了计算模态分析,得到其计算模态频率以及相应的振型.通过试验得到试验模态频率及振型,对所建立的试验和计算模型的模态相关性进行了计算和评估,得到计算和试验模态间的MAC矩阵及各自由度上的Co-MAC结果;利用模态相关性结果,修正原始有限元模型,从而提高了其模拟实际结构的精度,并为基于此有限元模型的更高精度动态分析模型的建立奠定了基础.

The method of the calculated modal analysis and the modal correlation is introduced, and the geometrical model and finite element model are established. The calculated modes of the engine under consideration are analyzed and its natural frequencies and the corresponding modes are calculated. At the same time the frequencies and modes are measured through experiments. A comparison between measured and calculated frequencies and modes is given, and then the MAC and the COMAC between calculated and measured modes are also presented. Using the results of the modal correlation, the finite element model is modiffied furthermore, in order to improve the precision of its simulating factual model.