空间相机桁架结构模态相关性分析

为有效地预示空间相机桁架结构的动态特性，需要对其进行模态相关性分析，目的在于检验分析结果的有效性和准确度，发现结构中的薄弱部位，但由于桁架结构是一复杂的杆板组合结构，计算结果中存在着大量次模态，从而无法与试验结果进行对比。基于上述问题，提出一种利用模态应变能比值来定量区分的方法，从密集的计算模态群中识别出桁架结构的主模态。主模态经模态向量缩减后与试验结果进行比较，鉴定它们之间的总体相关程度，若误差超过规定的界限，则通过调整模型参数、修改模型构型来寻找可能的误差源，反复这一过程，直到有限元模型能够很好地模拟实际结构的主要动态特性为止。分析结果预示了较好的试验和计算模态相关性，验证了有限元模型的有效性，为进一步的响应分析和振动控制设计提供了依据。

Model Correlation Analysis of Frame Structure of a Space Camera

To indicate the dynamic characteristic of the space camera effectively , the technique for correlation evaluation of the tested and calculated modes is studied in order to prove the validity and accuracy of the calculated result . But the calculated result including great deal partial modes fails to be compared with the tested result because the frame structure is a complicated beam - shell - composed structure. To solve this problem, a method which can distinguish these two kinds of modes conveniently with ratio of the modal strain energy , is then given . The correlation extent in collectivity is judged by comparing the primary modes reduced by modal vector with the tested result, thus , if the errors exceed regular limit, the error source is searched through regulating model parameter and amending model construction. This course is repeated until the model can simulate the primary dynamic characteristic of the actual structure . The final correlation is satisfactory and the finite element model of the frame structure certified in this paper can be used in the design of vibration control systems.