STRUCTURAL SYSTEM IDENTIFICATION UNDER RANDOM EXCITATION BASED ON ASYMPTOTIC WAVELET ANALYSIS

In this paper, a covariance-driven wavelet analysis technique is proposed for identifying the characteristics of linear structural systems from random vibration response measurements. Based on the asymptotic wavelet analysis theory, the paper proves that the ridges of Morlet wavelet coefficient magnitudes of structural covariance response under random excitations contain structural modal information and can be used to estimate structural modal parameters. In addition, if the spectral intensity of the random load is known, structural mass, stiffness and damping matrices can also be estimated. Results of a numerical study on a 3-storey frame show that the proposed technique can accurately estimate structural modal parameters and physical properties under random excitations. An experimental study on the north cable pylon of Sutong Bridge further verifies the accuracy and applicability of the proposed technique.