Moving window self-iteration PCE based OMA for slow linear time-varying structures

In order to reduce the time and space complexity of operational modal analysis (OMA) for slow linear time-varying (SLTV) structures based on moving window principal component analysis (MWPCA), this paper proposes a new moving window self-iteration principal component extraction (MWSIPCE) method. Different from getting principal components by singular value decomposition (SVD) or eigenvalue decomposition (EVD) in MWPCA algorithm, MWSIPCE just extracts the first-several-orders principal components by self-iteration. Comparing with MWPCA, MWSIPCE has lower time and space complexity. What’s more, this paper explains the reason of modal exchange in some data windows in detail, and gives an illustration to how to set window length L. The OMA results on non-stationary vibration response simulation signal of time-varying cantilever beam under white noise excitation show that this method can well identify the time-varying transient modal parameters (natural frequencies and modal shapes) for SLTV structures and has less time and space consume, the algorithm is also more precise than MWPCA.