Mixed-basis superposition method for the perturbation analysis of eigensolutions

✍ Scribed by Han, Wan-Zhi ;Song, Da-Tong ;Chen, Su-Huan

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 609 KB
• Volume: 12
• Category: Article
• ISSN: 1069-8299
• DOI: 10.1002/(sici)1099-0887(199612)12:12<835::aid-cnm24>3.0.co;2-x

✦ Synopsis

The modal superposition method is often used for computing the perturbation of eigenvectors in structural modification and model correction. However, it will bring about significant errors in the solution when the high-frequency modes are truncated. This paper presents a new method, which uses known modes construct a new basis of the N-dimensional Euclidean space (say, the mixed-basis), to calculate the first and second order perturbations of the known eigenvectors. In the present method only the known modes are used. The accuracy of this method not only has no relation to number of the truncated modes but is better than the truncated modal superposition method, in which only the known modes are employed. A numerical example of a truss structure with 36 degrees of freedom is given to illustrate the effectiveness of the method.