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New Software for Real-time Modal Identification

Y. KAYA, E. SAFAK

Abstract


Framework of the structural health monitoring (SHM) is to detect and locate the damage in structures. SHM involves data collection, continuous monitoring and analyzing them in real-time. Changes in modal properties during structure’s service life are strongly related to the damage potentials on the structure. Accurate estimation of modal properties (modal frequency, damping and mode shapes) is an essential step in SHM. Therefore, monitoring and accurate identification of real-time modal properties are crucial in order to have a good estimate in SHM. In this paper, a realtime modal identification technique for SHM applications has been developed. The technique is based on the modification of standard spectral analysis tools for real-time data, and utilizes running time windows to track time variations. A software package called KOERI-MIDS is developed for real-time modal identification. The software includes various user-selectable algorithms to identify modal properties, as well as options to plot their time variations and animations. The software has been tested with the ambient vibration data recorded from the Hagia Sophia Museum, a 1500 year-old historical structure in Istanbul. Modal properties of the structure have been identified accurately in real-time. Results of the Hagia Sophia test have been compared with the previous studies conducted by different researchers. Comparison shows that the results of the KOERI_MIDS are in good agreement with that of the previous studies

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