Open Access

ABSTRACT

Damage detection on beam structures based on fractal theory and wavelet packet transform

by Yong Huang¹, Hui Li¹, Jinping Ou¹

1 School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China
2 School of Civil and Hydraulic Engineering, Dalian University of Technology, Dalian 116024,China

The International Conference on Computational & Experimental Engineering and Sciences 2009, 12(2), 53-64. https://doi.org/10.3970/icces.2009.012.053

Abstract

A new damage identification method based on Fractal theory and wavelet packet transform is presented in the paper. The damage identification method utilize frequency-based domain message, time-based domain message and space based domain message effectively. NeXT method were first employed to reduce loading effect of random vibration measured from structures and then the vibration sinal were decomposed into the certain level wavelet packet components. For every time array of wavelet packet component then need to calculate the mean FD values as the ultimated FD values to reduce noise effect. The location of damage in the beam can be determined by the dramatic fluctuation appearing on contour of estimated FD and the extent of the damage can be estimated by FD-based damage index of δ. As a validation, the proposed method is applied to detect damage in a simply supported beam by numerical study. The successful detection of the damage in the beam demonstrates that the method is capable of assessing both the location and size of the damage. Noise stress tests are also carried out to demonstrate the robustness of the method under the influence of noise by considering all the information of every wavelet packet component synthetically.

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Keywords

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