Asymmetric Acoustic Scattering for Structural Health Monitoring

Abstract

Methods for constructing damage localization maps from networks of piezoelectric lead zirconate titanate (PZT) acoustic sensor measurements were investigated. A new approach, asymmetric acoustic Scattering (AAS), for damage detection and localization using PZT sensor arrays was developed, and the conclusions were favorable compared to commercial software results. The AAS method is simple, computationally efficient, and general because it does not require geometric details of the component or complex physical models. The approach estimates damage in five stages: (1) damage index (DI) measures are computed for individual sensors, (2) DI-weighted averages are computed for pairs of sensors, (3) DI-weighted averages are used to generate local DI maps, (4) local DI maps are combined into frequency-dependent global DI maps, and (5) frequencydependent DI maps are combined into global DI maps. The AAS algorithm generates temporal DI curves to increase the confidence of damage detection, whereas damage localization is accomplished with static distributed DI maps. Accuracy, robustness, and sensor array minimization methods for improving damage detection and localization were also investigated.