Lamb wave generation and detection using piezoceramic stack transducers for structural health monitoring applications

Recently, multifunctional devices called smart fasteners have been proposed and studied for structural health monitoring applications. Smart fasteners have an embedded piezoceramic stack transducer that can apply transverse force to a clamped structure or detect transverse vibration in the structure. Although the working principle of the smart fasteners is simple, how prestressed piezoceramic stack transducers can generate and detect guided Lamb waves in thin plate-like structures has not been studied. In this study, mathematical models for the Lamb wave generation and detection were derived in cylindrical coordinates based on stress boundary conditions, and the solutions were obtained in closed form. Then, the models were experimentally compared with a thin aluminum plate clamped by piezoceramic stack transducers. The experimental results match well with the theoretical prediction and show that the excited Lamb waves are predominantly in the symmetric mode due to the inherent symmetric boundary conditions. (paper)