In Situ Detection of Surface-mounted Pzt Transducer Defects Using Linear Reciprocity

Guided waves generated by Lead Zirconate Titanate (PZT) transducers are often used to detect structural damage for nondestructive evaluation (NDE) and structural health monitoring (SHM) applications. It is generally assumed that the surface-mounted PZT transducers are both undamaged and properly bonded to the host structure during usage. However, this assumption may not be valid, particularly under realistic operating conditions. In this study, a methodology for PZT transducer diagnosis is developed to identify abnormal transducers using linear reciprocity of guided wave propagation between pairs of surface-mounted transducers on metallic structures. The advantage of the proposed technique is that transducer bonding problems and PZT defects can be detected even when the system being monitored is subjected to varying operational, environmental or structural conditions. In addition, the complexity of the boundary conditions and the geometry of the structure do not affect performance. The effectiveness of this diagnostic technique is evaluated via numerical simulations and experiments with PZT transducers instrumented on an aluminum plate.