Damage detection of beam-like structures using wavelet transform and subtraction of intact and damaged mode shapes

Abstract

Detecting damages with low levels presents a significant challenge in structural assessment. Many existing methods fail to detect damages or cracks below a severity threshold of 10%. Localizing on-surface damages, especially those with low levels, adds to this complexity. This study introduces a novel technique to address these issues by employing wavelet transformation on the difference between damaged and intact mode shapes. A finite element model is developed to derive the governing equations for thin beams, yielding the mode shape signals necessary for analysis. These signals are subsequently decomposed using wavelet transform. Both numerical simulations and experimental validations confirm the method’s efficacy in detecting on-surface damages below the 10% level.