The existing vibration-based damage detection methods are commonly suffered from several limitations,such as,low immunity to noises and insensitivity to weak damages.To solve these problems,here a novel damage detection method was developed for plate-like structures using Katz’s fractal dimension sweep trace technique based on denoising with the dual-tree complex wavelet transformation (DT-CWT) and the affine transformation pretreatment. Firstly,the DT-CWT was used to denoise a original measured vibration signal,the denoised vibration signal was then decomposed into a set of modal shape curves in aplate’s vertical and horizontal directions.The decomposed modal shape corves were then transformed with affine transformation with affine transformation to make the lines no curvature turning point.Secondly,the fractal dimension scanning was applied to the transformed lines to form vertical and horizontal fractal dimension trace surfaces.Finally,the fused fractal dimension trace surface obtained by averaging vertical and horizontal ones was formed for the damage detection.The location and sizes of the damage were determined with the location and sizes of the sudden changes in the fused fractal dimension trace surface.The effectiveness of the proposed method and the importance of the DT-CWT denoising and the affine transformation pretreatment were demonstrated with two model tests.
白润波?1,2,徐宗美1,张建刚1. 基于双树复小波降噪和Katz分形维迹线融合的板类结构损伤检测[J]. 振动与冲击, 2017, 36(5): 87-94.
BAI Runbo1,2,XU Zongmei1,ZHANG Jiangang1. Damage detection for plate-like structures based on DT-CWT denoising and fusion of Katz’s fractal dimension trajectories. JOURNAL OF VIBRATION AND SHOCK, 2017, 36(5): 87-94.
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