CRACK DETECTION IN STRUCTURES USING VIBRATION MODAL PARAMETERS AND TIME DOMAIN RESPONSE

Detection of cracks in engineering materials, structures and machines at the early stage is an important issue of concern in the field of engineering. Cracks often occur first on the surface of concrete structures under load and provide an indication for further degradation. Fatigue can have significant influence on crack. It is therefore imperative to detect crack at the early stage to avoid catastrophic effects. For this reason, a number of methods have been developed by researchers to meet this objective. In this paper, a simple cantilever beam was considered to detect the presence of crack from measured vibration data. A beam with crack at different locations and another beam without crack were considered for the experiments. At different crack locations, natural frequencies, mode shapes and acceleration responses were determined. It was found that natural frequencies and mode shapes gave no significant presence of crack but time domain acceleration response method was able to detect the presence of crack.