Wavelet transform with reduced edge effects for damage identification in the beams under incremental damage

Document Type : Original Article

Authors

Faculty of Civil Engineering, University of Tabriz, Tabriz, Iran

10.22091/cer.2024.10087.1521

Abstract

In this study, wavelet transform with reduced edge effects is used to detect, localize and estimate the incremental damage at various levels in steel beams with different support conditions. For this purpose, a steel beam is modeled using finite element method for two types of support conditions, and three levels of incremental damage is defined by changing the stiffness of the member at a specified location. Then, dynamic displacement response of the beam under impulse loading was extracted and processed with continuous wavelet transform. The continuous wave-let transform of a finite length signal produces abnormally large coefficients close to the borders of the signal which is called "edge effects". To handle edge effects, different methods of signal extension are investigated. The obtained results from the process of extrapolated response by the cubic spline method show that the false indicators caused by edge effects are reduced significantly. In this case, there is a meaningful correlation between relatively large wavelet coefficients and damage location. The wavelet coefficients obtained from several measurements at the detected location of damage is used then to estimate changes in the level of incremental damage. It is shown that the variation of wavelet coefficients at the location of damage is reasonably estimate the various damage levels. Finally, the effects of the presence of low levels of noise in the measured responses of the beam on the proposed damage detection process are evaluated.

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Civil Infrastructure Researches

Articles in Press, Accepted Manuscript
Available Online from 03 April 2024

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