DETECTION OF CRACK LOCATION AND SIZE IN STRUCTURES USING HIGHER HARMONICS OF EXCITED FREQUENCY

The major challenge structural engineers ’ face is the problem of detection of crack locations and size in structures. This paper proposed a method on the use of the amplitude of higher harmonic components of excited frequency of vibration for the detection of crack, its location and size. A cantilever beam has been considered for the study and Finite Element (FE) model was developed. Acceleration responses when excited at the first mode were calculated for healthy case and crack at different locations. The presence of higher harmonics of the excited frequency showed that presence of crack and the amplitude of higher harmonic component was used for the detection of its location and sizes. In conclusion, it was observed that spectrum analysis gives a good indication of the presence of cracks because of the presence of higher harmonics of fundamental frequency due to cracks. However, detection of crack location and size at the earliest possible stage is very important as it prevent major failures. Harmonic analysis proves to be an outstanding method necessary to detect the location and size of cracks