Adhesive interface layer effects in PZT-induced Lamb wave propagation

In PZT-induced acousto-ultrasound techniques, the adhesive layer between a PZT and a host structure significantly affects sensor signals. However, its effects have been barely studied so far. A numerical model is essential to fundamentally understand the role of the adhesive interface. Using the hybrid spectral element, the effects of the adhesive bond-line layer on the Lamb wave generation and reception were modeled and compared with available test data for validation of the hybrid spectral element. The validations were conducted with different adhesive layer thicknesses. The trends in simulation results agreed well with the experiments. Parametric studies are presented to understand the adhesive layer effects. In these studies, adhesive thickness and stiffness, and PZT diameter and thickness, are selected as parameters. The physics of the adhesive layer are then discussed