Modal Parameters Identification Based on Equalization Principal Component Analysis

Abstract

Aiming at the magnitude influence of different discrete points in modal parameters identifications with traditional principal component analysis (PCA), a method of modal parameters identifications by equalization PCA is proposed in this paper. The basic idea is using the mean of time domain response data before identifying modal parameters with PCA. On the premise of not losing the main information of the original data, the influence of magnitude on the data is weakened. Taking a doubly-clamped beam as an example, modal parameters of the beam are identified by traditional PCA and equalization PCA with the same constraints of principal component cumulative contribution rate. The results show that compared with the traditional PCA, equalization PCA can effectively identify more orders of modal parameters. The errors of vibration modal shapes and natural frequencies identified by equalization PCA are allowable.