Experimental study on impedance-based damage detection considering temperature effect and operating condition

Impedance-based damage detection technique has been pointed out as a useful method for structural health monitoring. However, it is needed to consider the temperature effect on the impedance signature to apply this technique in real structures. Also, for practical application, it is advantageous to consider the operating conditions such as vibration and live load. And, the correlation between the measured impedance data and the analysis results can improve the capability of structural health monitoring. In this study, an impedance-based damage detection method considering the temperature effect and operating conditions is experimentally researched for an aluminum beam, and the correlation between the impedance damage indices obtained from experiment and the equivalent bending stiffness for the cracked beam calculated by analysis is investigated. The long-term measurement under vibration is carried out, and it is found that the damage can be clearly estimated, while monitoring the warning criterion together, after compensating the temperature effect. It is also found that as the crack size increases, the variation in the damage indices increases, and the correlation between the impedance damage index due to crack propagation and the analyzed equivalent bending stiffness of the cracked beam is partially identified.