Monitoring of growing fatigue damage using the E/M impedance method

The electro-mechanical (E/M) impedance-based method is one important and effective method in damage detection. The basic concept of the impedance method is to monitor the variations in the structural mechanical impedance spectrum caused by damage in the structure. Comparing the impedance spectrum to a baseline measurement of the undamaged structure, the real part of the E/M impedance reflects the state of structural health in the local area, therefore, the structural damage can be localized, a local-area self-sensing method is implemented. In this paper, an aluminium plate mounted on an electromagnetic shaker is used to detect growing fatigue damage using the impedance method. The growing damage is documented by an increase of the indicators. For the case of a static artificial damage the concept is also demonstrated to an Airbus A320 fuselage part using 9 self-sensing elements on the stringers.