EPCA basaed Modal Parameters Identification with Test data

During the process of modal parameters identification by traditional principal component analysis (PCA), to reduce the effects of the magnitude influence of response data on different discrete points, a method of identifying modal parameters from test data based on equalization PCA (EPCA) is proposed in this paper. The basic idea of this method is equalizing the test data before identifying modal parameters by PCA. Besides, to decrease the undesirable influence of the trend in the test data, we will first remove the trend in the response data. To verify the method proposed in this paper, two different beams’ modal tests have been taken. The modal parameters have been obtained by the modal tests and the response data with different points has been collected either. The modal parameters are identified by traditional PCA and EPCA with the same constraints of principal component cumulative contribution rate with the response data. The results show that, compared with the traditional PCA, the modal shapes identified by EPCA are more similar to the modal shapes obtained by the modal tests.