Damping Matrix Identification Using the Spectral Basis Technique

Abstract

This paper presents a method for estimating the damping matrix of a structural system when the stiffness matrix, mass matrix, and frequency response data are given. The method is based on the fact that the forced responses of a structure can be decomposed into linear combinations of sets of frequency-dependent function. A set of orthonormal basis vectors of the frequency response is first determined. The forced responses are then expressed as linear combinations of these basis vectors. The coefficients of the damping matrix are then solved using the pseudo inverse of these basis vectors. Because the vectors that span the space of the frequency response are required to be linearly independent, an orthogonalization process is used to identify the number of significant basis vectors. Several examples are presented to illustrate the use and advantages of the proposed method.