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

TLDR

Guided Lamb waves, particularly the fundamental flexural A0 mode, are employed in this study, though the technique is not limited to this mode. The study proposes a damage detection method using an innovative 2D phased sensor array made of piezoelectric paint for in‑situ detection on thin isotropic panels with guided Lamb waves. The authors design, fabricate, and test a spiral 2D phased sensor array of piezoelectric paint on an aluminum panel, generate steered array responses via directional filtering, and enhance analysis with empirical mode decomposition and Hilbert–Huang transform. A new damage detection algorithm with threshold setting and damage‑index calculation detects holes and a simulated crack, and the damage indices consistently increase with damage size.

Abstract

A damage detection method based on an innovative 2D phased sensor array made of piezoelectric paint is proposed for in situ damage detection of a thin isotropic panel using guided 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 sensor array with a spiral configuration is fabricated using a piezoelectric composite (piezopaint) patch and used for detecting damages in an aluminum panel. Steered array responses are generated from the raw sensor signals using a directional filtering algorithm based on phased array signal processing. The fundamental flexural (or transverse), A0 mode, of the guided Lamb waves is used though the sensing and analysis technique is not limited to the mode used in this work. To enhance the proposed analysis technique, empirical mode decomposition (EMD) and a Hilbert–Huang transform (HHT) are applied. A new damage detection algorithm including threshold setting and damage index (DI) calculation is developed and implemented for detecting damages in the form of holes and a simulated crack. The characteristic damage indices consistently increase as damage size grows.