Airplane hot spot monitoring using integrated impedance and guided wave measurements

In this paper, an integrated impedance and guided wave (IIG) damage detection technique using permanently embedded lead zirconate titanate (PZT) transducers is advanced specifically for online monitoring of critical hot spots within a composite airplane wing structure. A full-scale airplane wing segment is designed and manufactured to validate the developed online structural health monitoring system. First, structural hot spots, which are vulnerable to damage due to high stress concentration, are determined through finite element analysis during the design stage of the airplane wing segment. Next, the parameters related to PZT design, size, number, cabling, and location are determined, and the PZTs are embedded near the identified hot spots. Then, the applicability of the IIG technique to detection of debonding on a composite skin and bolt loosening on an aluminum fitting lug is experimentally examined under varying temperature and static loading conditions. Finally, the long-term durability of the PZTs is experimentally investigated using a PZT self-diagnosis technique over 2?years. Copyright (C) 2012 John Wiley & Sons, Ltd.