航空相机的模态分析及轴承模型的修改

Mode Analysis of the Aerial Camera and Modification of the Bearing Model

为了研究航空相机的动态结构刚度,运用有限元分析和试验相结合的模态分析法获得系统的固有频率和模态振型。应用大型通用有限元软件MSC.Nastran/Patran建立了航空相机的有限元模型,分析得出该相机的固有频率和模态。利用有限元分析结果中的模态振型指导试验模态分析中测点位置的选择,通过试验测得相机系统固有频率的实际值,并与有限元分析结果进行比较,验证了有限元分析的合理性,确定相机结构达到了设计性能指标。在有限元建模中采用改进的线性轴承模型后,降低了系统的计算难度,使有限元分析结果与试验值更加接近。

For studying the dynamic structural stiffness of the aerial camera, the thesis obtains the natural frequencies and the modes by combining FEA with experiment mode analysis. The FEM model of the aerial camera is established using the finite element software MSC. Nastran/Patran. The natural frequencies and the modes of the camera are acquired by FEA. The results of the FEA direct the selection of measuring points in the experiment mode analysis. The real value is obtained from the experiment and compared with the analysis result. The experiment verifies the rationality of the analysis of the FEM and confirms that the structure achieves the design performance index. Using the modified linear bearing model reduces the computation difficulty. Moreover, the result of FEA is closer to the experimental data.