Damage detection in structures using vibration measurements

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Date

2003

Author

Aydoğan, Mustafa Özgür

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Cracks often exist in structural members that are exposed to repeated loading, which will certainly lower the structural integrity. A crack on a structural member introduces a local flexibility which is a function of the crack depth and location. This may cause nonlinear dynamic response of the structure. In this thesis, a new method is suggested to detect and locate a crack in a structural component. The method is based on the fact that nonlinear response of a structure with a crack will be a function of the crack location and crack magnitude. The method suggested is the extension of a recently developed technique for identification of non-linearity in vibrating multi degree of freedom system. In this method, experimentally measured receptances at different forcing levels are used as input, and the existence and location of a nonlinearity are sought. In order to validate the method, simulated experimental data is used. Characteristics of a cracked beam are simulated by using experimentally obtained analytical expressions, given in the literature. The structure itself is modelled by using finite element method. Several case studies are performed to test and demonstrate the applicability, efficiency and sensitivity of the method suggested. The effect of crack depth on nonlinear system response is also studied in numerical examples.

Subject Keywords

Nonlinear theories, Dynamics

URI

http://etd.lib.metu.edu.tr/upload/1058809/index.pdf
https://hdl.handle.net/11511/13797

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Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

M. Ö. Aydoğan, “Damage detection in structures using vibration measurements,” M.S. - Master of Science, Middle East Technical University, 2003.