Effect of External Vibration on PZT Impedance Signature of Plate Structure

摘要

Electromechanical impedance (EMI) technique using lead zirconate titanate (PZT) transducers has been increasinglyapplied to structural health monitoring (SHM) of aerospace, civil and mechanical structures. The PZT transducers areusually surface bonded to or embedded in a structure and subjected to actuation so as to interrogate the structure at thedesired frequency range. The interrogation results in the electromechanical admittance (inverse of EMI) signatureswhich can be used to estimate the structural health or integrity according to the changes of the signatures. In theexisting EMI method, the vibration of the structure caused by the external excitations has been considered only for onedimensional scenario. This paper develops a two dimensional EMI model to account for the effect of externalexcitation on the PZT admittance signature. An application is illustrated with modeling of a simply supported Kirchoffplate interrogated by a single surface-bonded PZT transducer. Numerical simulation is also carried out to verify thetheoretical model. Finally, the effect of external excitation on PZT impedance signature is discussed.