动力学参数修改的耦合模态子空间摄动法

在结构动力学设计中，如果系统的质量矩阵和刚度矩阵有小修改，则矩阵摄动法是结构动态特性再分析的重要方法，当系统具有重频或近频耦合模态时，常规的矩阵摄动法失效。本文研究了多组耦合模态结构动力学参数修改的子空间摄动法，将系统振动模态分布为耦合模态与弧立模态，由数组相互耦合的模态张成耦合模态子空间，采用初始模态坐标变换后，在维数不大的耦合模态子空间内进行了特征分析，然后作第二次耦合模态子空间坐标交换，最扣

Coupled-Mode Subspace Perturbation Method for Dynamic Parameter Modification

In the dynamic design of structural systems,the matrix pertrubation method is an important one for analyzing the structural dynamic characteristics when the mass and stiffness matrices of the structural system have small changes. The ordinary matrix perturbation method fails to deal with the structural system of repeated or closed frequency modes. A subspace perturbation method for structural dynamic modification of several groups of coupled-modes vibration systems is studied. The vibration modes are divided into two classes:separated and coupled.The coupled-mode subspace is spanned by the groups of coupled modes. After taking the coordinate transformation by initial modes,the solution of a low-order eigenvalue problem is calculated in the coupled-mode subspace.Having carried out the next coupled-mode subspace modal transformation, a completely.perturbed eigensolution of the updated system is given by the present coupled-mode subspace perturbation method. It is demonstrated by the sample problem that the method presented here is simple,accurate,useful and efficient.