A Time Domain Identification Technique: The Oversized Eigenmatrix (OEM) Method

Abstract

A method of identifying natural frequencies and associated damping ratios of a structure from its free decay response is presented. The method is based on the Prony’s algorithm with which the idea of using an oversized math model as in ITD to reduce the noise effect is incorporated. Two approaches are proposed for use in distinguishing the true poles from the extraneous poles introduced by oversizing the eigenmatrix. The simulated experiments on a cantilever beam show high efficiency of the method in reducing the noise effect on the identification results under extremely noisy conditions.