A review of structural health monitoring and damage detection using wavelet transform: the case study of damage detection in cantilever beams

Structures suffer local damages due to various reasons. If these damages are not identified, they could be aggravated by natural disasters such as earthquakes or artificial factors such as unprincipled excavations, leading to total destruction of the structure. As a result, health monitoring in structures and their elements is regarded as one of the most significant research topics in civil, mechanical, and aerospace engineering. A damage detection method is to process the time or frequency domain of structural responses. In this context, wavelet transform is one of the processing methods for both time and frequency domains, and many studies have utilized it to investigate structural health monitoring. In this paper, a comprehensive review was conducted on the published studies. Besides, damage detection was performed by considering the vibration mode shapes of a defective cantilever, which were used as wavelet-transform input signals. The diagram of the detail coefficients resulting from the wavelet analysis of the input signal presented the maximum and minimum values in the defective positions. These findings support the efficiency of using wavelet transform in damage detection. Further, the sensitivity of damage detection based on wavelet transform to the severity of damages showed that with the rise in damage severity in a location, a larger relative jump occurs in the output signal of all modes.