Detecting Crack Damage in Beam Bridges under Moving Loads by Combining Discrete Wavelet Transform and Independent Component Analysis of Two Sensor Measurements

It is still a challenging problem to detect crack damage in beam bridges under moving loads using limited sensor measurements with noise pollution. This study proposes a baseline-free crack damage localization method for beam bridges by combining the discrete wavelet transform (DWT) with independent component analysis (ICA). By considering the acceleration responses of the beam bridge structure at two locations under moving loads and the influence of measurement noises, the noisy acceleration responses are decomposed by wavelet transform, and the high-frequency parts of the wavelet coefficients from the two responses are utilized for signal reconstruction. Subsequently, the reconstructed signals from the two sensors as input, the FastICA algorithm is employed to separate independent components from the mixed signals. Finally, independent component signals containing crack damage information can be obtained, and the crack damage of the beam bridge is localized through the position of singular values in these independent component signals. Numerical simulations of localizing single and multiple cracks in a simply supported beam under moving loads are used to demonstrate that the method exhibits strong robustness against measurement noises and remains effective under various moving load configurations.