2015 CSCE Annual Conference Regina - Building on our Growth Opportunities

2015 CSCE Annual Conference Regina - Building on our Growth Opportunities Conference


Title
DAMAGE IDENTIFICATION USING FREQUENCY SENSITIVITY FUNCTIONS

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Author(s)
Mr. Ayman Thabit, The American University in Cairo (Presenter)
Mr. Mohamed Abdel Mooty
Dr. Ezzat Fahmy, The American University in Cairo
Abstract

The inevitable occurrence of damage in structures necessitates the availability of an efficient and reliable damage identification routine. The recent boom in construction and the surge in the scale of structures have proven that relying solely on the classical approach to damage detection lacks practicality. Vibration-based techniques, which emerged in the early 1970s, have been successfully utilized in many damage detection applications. One of the most widely known vibration-based methods relies on detecting damage through the measured shift in resonant frequencies. Although this technique has the advantage of simplicity of the measurement process, its sensitivity to damages in large scale structures has been a subject of investigation. Additionally, the influence of variations in ambient conditions has been found to be measurable. This paper presents a new technique for detecting damage in beam-type structures by utilizing the frequency sensitivity functions of the first few vibration modes. The proposed method was successfully tested on Finite Element models of single-spanned beams. The effect of changes in both uniform and gradient temperatures was also addressed in this research. The capability of the presented method in identifying damage in relatively long period structures was investigated by applying the proposed technique on a numerical model of a cable-stayed bridge.  The method was also tested using the results of pervious experimental investigation in which damage was simulated at different locations of a cantilever beam. The presented technique showed promising capabilities in identifying the location and magnitude of damage.