Damage Identification Using Piezoelectric Impedance Approach and Spectral Element Method

The basic idea of the impedance-based damage detection is that the electrical impedance of the piezoelectric transducer attached to a structure is directly related to the mechanical impedance of the host structure. Therefore, damage effect can be reflected in the change of the piezoelectric impedance curves before and after damage occurrence. As the piezoelectric impedance information can be extracted at relatively high-frequency range, such a method is considered to be sensitive to small-sized damage. Previous studies on this approach mainly focus on declaring damage occurrence. In this research, we develop a model-based method that can identify both the location and the severity of the damage. The model is built upon the spectral element method, which has high computational accuracy and numerical efficiency in the high-frequency range. Using the difference between the impedance curves of the system monitored and the system at its healthy baseline state as input, an inverse identification procedure is formulated to extract directly the property change of the structural elements. Extensive numerical and experimental studies are carried out to demonstrate the effectiveness of the proposed method.