Mechanical behaviour and health monitoring by acoustic emission of sandwich composite integrated by piezoelectric implant

The feasibility of embedding piezoelectric sensor to detect the acoustic emission (AE) activities in sandwich composites has been investigated experimentally. A series of sandwich specimens with and without embedded piezoelectric sensor were tested in three-point bending in static and fatigue loading while continuously monitoring the response by the AE technique. Experimental results show that the incorporation of piezoelectric sensor causes low degradation of mechanical properties of material. The analysis and observation of AE signals leads to the identification of the acoustic signatures of four damage mechanisms in sandwich materials. One of the major differences between the two types of materials (with and without embedded sensor) is the intense acoustic activity in the integrated material.