IDENTIFICATION OF STRUCTURAL MODAL PARAMETERS WITH WAVELET TRANSFORMATION

Structural modal parameters reflecting intrinsic characteristics of a structure are critical factors in vibration-based damage detection and health assessment. Firstly,application of wavelet analysis for important identification of structural modal parameters under environmental excitation is introduced.First several natural frequencies of civil engineering structures are mainly in low frequency region and signal-noise ratio of structural response signals under environmental excitation is usually lower,thus,emphasis has then been laid on the denoising technology based on wavelet analysis,which filters the curde signals and gains more worthy information by restraining high frequency components and extracting low frequency ones.The comparison between identified results of an actual tall building through field test by using traditional Fourier transformation(FT), short-time Fourier transformation(STFT) and Wavelet transformation(WT) and the theoretical results from its finite element model indicates that the wavelet-based method is able to extract its characteristics more accurately and more effectively.