Piezoelectric-paint-based two-dimensional phased sensor arrays for structural healthmonitoring of thin panels

Abstract

A damage detection method based on an innovative 2D phased sensor array made ofpiezoelectric paint is proposed for in situ damage detection of a thin isotropic panel usingguided Lamb waves. A design analysis of candidate 2D arrays based on spiral,cruciform and circular element layouts is performed. In this study, a 2D phased sensorarray with a spiral configuration is fabricated using a piezoelectric composite(piezopaint) patch and used for detecting damages in an aluminum panel. Steered arrayresponses are generated from the raw sensor signals using a directional filteringalgorithm based on phased array signal processing. The fundamental flexural(or transverse), A0 mode, of the guided Lamb waves is used though the sensingand analysis technique is not limited to the mode used in this work. To enhancethe proposed analysis technique, empirical mode decomposition (EMD) and aHilbert–Huang transform (HHT) are applied. A new damage detection algorithmincluding threshold setting and damage index (DI) calculation is developed andimplemented for detecting damages in the form of holes and a simulated crack.The characteristic damage indices consistently increase as damage size grows.