Influence of structure-actuator interactions and temperature on piezoelectric mechatronic signatures for NDE

Abstract

In recent years, the piezoelectric-ceramic (PZT) patches are increasingly been used as impedance transducers for non-destructive evaluation (NDE) of structures. In this application, the electrical admittance of a PZT patch surface bonded to the structure is utilized as a diagnostic signature of the structure. The operating frequency is typically maintained in the kHz range for optimum sensitivity in damage detection. The electro-mechanical interaction between the host structure and the bonded patch is key to the detection of damage in this NDE technique. Although the method is well established for a wide variety of structures and material types, very little research has focused on the fundamental structure-PZT interaction. This paper reviews the fundamental electro-mechanical coupling between the structure and the PZT patch and introduces a new concept of 'active' signatures, whereby it is possible to utilize the direct interactive component of the signature for NDE afte filtering the 'inert' component. Consequences of this concept, which include increased sensitivity to damage and reduced influence of temperature fluctuations on signatures are highlighted.