In Lamb wave based techniques for damage detection, Piezoelectric Wafer (PW) transducers are often used for actuating Lamb wave. They offer advantages such as portability and, cost effectiveness. However, because of prolonged use, excessive voltage supply, or improper bonding onto the host structure, these PW actuators may get partially debonded from the host structure. In this paper, the nonlinear effect of this debonding on the behavior of Lamb wave manifested in the form of higher harmonics, is studied both experimentally and through Finite Element (FE) simulation. Augmented Lagrangian algorithm is used in FE simulation to solve the contact problem at the breathing debond. Three higher harmonics are observed in the experiments and also in the FE simulation. Morlet wavelet transform is implemented in the study for time-frequency analysis and the results are reported in the paper. Nonlinearity parameter β obtained from fundamental and second harmonics in the experiments and the simulation, is found to be increasing with increase in the debonding area. This shows that actuator debonding produces contact nonlinearity and thereby induces higher harmonics in the Lamb wave. Therefore, in damage detection using Lamb wave based nonlinear techniques, the higher harmonics produced may get influenced by the false higher harmonics produced by actuator debonding, leading to incorrect results. Also these false higher harmonics resulting from actuator debonding may show illusory presence of defect in a pristine material, if bonding of the actuator is not taken care of properly.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.