Impedance resonant frequency sensitivity based structural damage identification with sparse regularization: experimental studies

Electromechanical impedance (EMI) based structural health monitoring methods have been successfully applied to various engineering fields. However, the studies on damage quantification using EMI based techniques are still limited. In general, conventional EMI based methods evaluate the changes in the host structure by comparing the difference between impedance responses from undamaged and damaged structures, with statistical damage indicators, i.e. root mean square deviation (RMSD) and cross correlation. These damage indicators can detect the existence of damage in structures, but are not able to precisely locate and identify the severity of damages. This paper presents experimental validations on a novel structural damage identification approach based on the sensitivity of resonance frequency shifts in the impedance and sparse regularization technique. The coupled finite element model of the piezoelectric transducer and host structure is developed and calibrated for the damage quantification. A limited number of measured resonance frequency shifts are used to identify the damage in a number of segments in the host structure. Experimental verifications are conducted on narrow aluminum plates to demonstrate the accuracy and performance of the presented approach. The identification results demonstrate the effectiveness and performance of using the proposed approach for structural damage localization and quantification. To investigate the capacity of impedance based technique for SHM with the proposed approach, numerical studies are further conducted to discuss the sensitivity range of this method.