Fe analyses for the assessment of the coverage area of a guided waves SHM system

Ultrasonic guided waves (GW) can inspect large structures since they can propagate long distances with low attenuation. They are widely used in Structural Health Monitoring (SHM) to extract useful information about the actual state of the component. However, in a finite plate, due to scattering caused by both damage and boundaries, the extraction of damage features from the recorded signals can be tricky and plays a key role in the implementation of this technology on real components. In this paper, starting from a developed damage detection algorithm, the sensitivity of an SHM system, based on GW propagation and piezoelectric (PZT) sensors, is numerically investigated. The test case consists of an aluminium plate equipped with five PZTs. Different damages are modelled outside the PZTs network coverage area, positioning them increasingly distant from the PZTs. Results of the Finite Element (FE) analyses allow to evaluate the effectiveness of the developed damage detection method and also to estimate the threshold distance across which detecting damage is prevented.