大修改结构特征向量重分析的混合基展开法

Mixed-basis Superposition Method for Eigenvector Reanalysis of Large Modified Structures

为拓展基于矩阵摄动理论的结构重分析方法在实际工程中的适用范围,提高重分析计算精度,针对结构模态空间不完备和参数大修改提出了结构动力重分析的混合基展开法。利用已知的少数几个可能不连续的低阶模态构造出整个模态空间的一个混合基,同时将反映结构参数改变的质量矩阵和刚度矩阵的增量表示为高次增量形式,保留了经典摄动法简单易行的特点。数值算例表明,所提出方法适用范围广,极大提高了结构大修改下的动力重分析计算精度。

In order to extend the application range of the structure reanalysis method based on the matrix perturbation theory in engineering practice,and to improve the calculation precision of reanalysis,an improved mixed-basis superposition method of dynamical reanalysis is proposed for large modified structures without complete modal space.The known modes are used to construct a new mixed-basis of the modal space,and the changes in the stiffness matrix and mass matrix reflecting the changes of structural physical parameters are represented as the incremental form of higher order.The present method is as simple and easy to operate as the classical perturbation method.The numerical results show that the presented method yields high precision for dynamical reanalysis of large modified structures.