Variable Residue Method for Modal Parameter Estimation

Abstract

A new method for the estimation of modal parameters is presented in this paper. Unlike the majority of the existing methods which involve complicated curve fitting and interpolative procedures, the proposed method calculates the modal parameters by using different sets of frequency response function (FRF) data points around resonance and assumes that the residue (contribution of other modes) of the mode to be analyzed can vary with different frequency. Such features can make the proposed method be very accurate and versatile, especially in the case where modal parameters of close modes are to be identified. The method is further developed to cope with the practical case where FRF data are measured from nonlinear structures and has been found to be very effective. To demonstrate its practical applicability, the method has been applied to data measured from real engineering structures, both linear and nonlinear, and promising results have been obtained.