计算特征向量摄动量的混合基展开法

在结构修改和模型校正中，模态展开法是计算特征向量摄动量的常用方法之一，但当高阶模态被截断时，它会带来很大的截断误差。本文利用已知的有限阶模态，构造了Ｎ维欧氏空间的一个新基－混合基，并将特征向量的摄动量在新基上展开来计算特征向量的一、二阶 摄动量。该方法使得不管截模态个数的多少，其精度总与全模态展开法相同，且计算量都远少于全模记展开法；与改进的部分民开法相比，本方法不要求所截留的模态边连续的低阶模态

MIXED-BASIS SUPERPOSITION METHOD FOR COMPUTING THE PERTURBATION OF EIGENVECTORS

The modal superposition method is often used for computing the Perturbation of eigenvectors in the modification for structural and correCtion for model. However, it will bring about significant errors in the solution when the high-frequency modes are truncated. This paper presents a method, which uses the known modes to constructe a new basis of the N-dimension Euclidean space, to calculate the first and second order perturbation of the known eigenvectors. The new basis is called mixed-basis. The accuracy of this method is independent of the number of the truncated modes and is as accurate as that of the modal method, even for the case that the known modes are arbitrary. In addition, the computing work is less than that of using modal method. So it is very imporant in the modification for structure based on the test modes.