Abstract:

A coupled-mode subspace perturbation method is presented in this paper. When the structural system has closed natural frequencies, the modes are coapled and the ordinary matrix perturbation method is invalid. By use of the initial modal coordinate transformation, the coupled-mode subspaca is defined. After the next subspace modal transformation, the coupled-mode subspace perturbation method gives the complete perturbed eigensolution. The sample problems demonstrat that the method presented here is accurate and efficient.

Key words: structural dynamics, vibration analysis method, perturbation method, small parameter method