Frequency-Domain Method of Stiffness Eccentricity Identification Based on Successive Variational Mode Decomposition

An improved frequency-domain method for identifying the center of rigidity in multistorey, noncoaxial stiffness-eccentric structures is presented. This approach utilizes successive variational mode decomposition (SVMD) to analyze acceleration responses at the center of mass. By generating power spectral density (PSD) plots for the decomposed acceleration signals, the method allows for the selection of frequency bands that are close to the target spectral peaks. The proposed technique leverages data from these identified frequency bands in a QR decomposition combined with a least-squares algorithm to determine the center of rigidity. This strategy effectively avoids the matrix inversion procedures typically required in time-domain methods, thus enhancing both computational efficiency and robustness. To validate the effectiveness of this method, a four-storey numerical example is employed. Additionally, the technique has been applied to the Yingxian Wooden Pagoda, where it successfully identified the center of rigidity at each storey, demonstrating its practical utility in actual applications.