Abstract
Repeated or closely packed modal frequencies are common physical occurrences for vibrating structures which are complex or possess multi-planes of symmetry. The computation of the sensitivity to structural modifications for these frequencies and mode shapes is made difficult by the fact that the mode shapes are not unique, since any linear combination of eigenvectors corresponding to a repeated eigenvalue is also an eigenvector. This paper extends the work of Chen and Pan, who used modal expansion techniques for accommodating the sensitivity analysis of structures with repeated eigenvalues. Starting with a discussion of the physical significance of sensitivity analysis for repeated frequency modes, the paper presents a derivation of the governing equations for the derivatives of a repeated eigenvalue.
Original language | English (US) |
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Pages (from-to) | 197-213 |
Number of pages | 17 |
Journal | NASA Conference Publication |
State | Published - 1987 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Aerospace Engineering