Modal Parameter Identification of Beam Structures Based on Improved Empirical Fourier Decomposition

Abstract In order to enhance the accuracy of modal parameter identification for beam structures, this paper proposes an improved empirical Fourier decomposition (EFD) method to decompose signals and identify modal parameters under environmental excitations. The identification method includes two aspects. First, the segmentation boundaries of signal frequencies are determined through multiple signal classification (MUSIC), replacing the Fourier spectrum that is susceptible to noise interference. Second, an improved EFD (EFDM) is employed to decompose the collected vibration responses into multiple modal components. The free vibration responses of these modal components are obtained through the Hilbert transform (HT) and random decrement technique (RDT), and applied to identify the modal parameters of the target structure. Numerical and experimental studies confirm the effectiveness and accuracy of the proposed method to identify the modal parameters of the structures, demonstrating its noise resistance and robustness.