部件试验模态综合的简便方法

本文将一种基于完备模态基的模态综合技术应用于子结构的试验模态综合,获得成功。这种半试验半理论的模态综合方法是一种较为简便的、要求试验工作量较小的试验模态综合法,因为它只要求测量子结构的振动模态和频率即可。数值仿真结果表明,这种简便的试验模态综合法是行之有效的。

Simplified Method for Synthesis of Component Test Modes

The synthesis of component test modes and/or the synthesis technique of analytical and experimentalmodes have been investigated by some researchers.According to classical free interface method,so-calledStatic Residual Flexibility(SRF)needs to be measured with the case that the component is fixed,which isnot ease.Some years ago,the concept of Dynamic Residual Flexibility(DRF)that describes the contribu-tion of truncated high order modes was proposed.The dynamic residual flexibility is a kind of deformationshape generated by harmonic force with very low frequence.Whether SRF or DRF,measuring them is dif-ficult.In order to avoid this difficult,a simplified synthesis technique of combined experimental/analyticalmodes is developed in this paper.The technique requires only measurement of normal modes of variouscomponents.Then these test normal modes and a set of equivalent analytical high order modes,are com-bined as the complete basic vector space in Ritz analysis.It is common knowledge that the precision of Ritzmethod is depended principally on degree of the completeness of basic vector space and is not given simplyby the shape of each basic vectors.Also we know that Ritz solution is accurate when the basic vector spaceis complete.Base upon the principle above-mentioned,the simplified method does not need substructural fi-nite element models possessing high precision.Finally point out,adopting popular model correction tech-nique is necessary in the simplified method.Example shows that stated method is successful,because itsprecision is very satisfactory.