Lamb Wave Actuation and Propagation Using Flexoelectric Transducers

Abstract

In recent years, actuation and propagation using a relatively novel electromechanical effect, namely flexoelectricity, have become an emerging field of research. In this article, we explore the use of flexoelectric dielectrics for Lamb wave actuation and propagation for structural health monitoring (SHM) applications. Towards this objective, an analytical solution is presented for Lamb wave generation and propagation in plate-like structures using flexoelectric-piezoelectric transducers bonded to the host plate surface through an adhesive layer. The model considers both interfacial shear and peel stresses at the interface of the transducer and the plate. These interfacial stresses under applied electric actuation are determined based on a one-dimensional (1D) model, which assumes Kirchhoff plate-like behaviour for both the actuator and the host plate. A 2D elasticity solution is obtained for Lamb wave propagation in the host plate under the interfacial shear and peel stresses obtained from the above 1D model considering plane strain conditions. This solution is obtained in the wave number domain by applying Fourier transform spatially. Finally, the response is obtained in the physical domain by applying the inverse Fourier transform and residue theorem. The strain response at the plate surface is compared with the rigid bonding model to illustrate the effect of bonding compliance. The numerical study demonstrates the effect of the adhesive layer on the response for different excitation frequencies.