Experimental and numerical studies on damage localization of simply supported beams based on curvature difference probability method of waveform fractal dimension

摘要

Accurate structural damage localization in engineering is still a challenge due to high noise and low accuracy of the structural finite element model. With the most basic type of construction, the simply supported beam is the most widely used type of structures in short and medium span bridges. Therefore, it is imperative to study their damage detection methods, which can be used in engineering. To solve this problem, an alternative method for damage detection is proposed in this study on the basis of fractal theory and curvature mode shapes method: the curvature difference probability method of waveform fractal dimension. The influence of different amplitudes of excitation on results and the robustness against noise are also discussed. Based on a simply supported beam model in the laboratory, both the experimental and numerical results using the technique under step or pulse excitation indicate that the proposed method can be used in damage localization very well, and it exhibits high-noise insusceptibility: it is still feasible even if the noise level is up to 15%, which lays a good foundation for engineering application. Moreover, the proposed technology needs no finite element model of the detected structures. Therefore, it is quite simple in the procedure.