Boundary element modelling of ultrasonic Lamb waves for structural health monitoring

In this paper, a novel boundary element plate formulation is proposed to model ultrasonic Lamb waves in both pristine and cracked plates for structural health monitoring (SHM) applications. Lamb waves are generated and sensed by piezoelectric discs. An equivalent pin-force model is newly proposed to represent the actuation effect of piezoelectric discs, which is more accurate than the classical pin-force model. The boundary element formulation is presented in the Laplace-transform domain based on plate theories, which allows three-dimensional analysis of Lamb wave behaviours, such as propagation and interaction with cracks, in thin-walled structures. A damage detection algorithm is used for crack localization alongside the BEM-simulated data. The BEM solutions show excellent agreement with both 3D finite element simulation and experimental results. (paper)