Embedded Damage Localization Subsystem Based on Elastic Wave Propagation

This article presents an embedded signal processing subsystem constituting a part of a whole structural health monitoring system (SHM). Typical SHM system is responsible for elastic wave generation and sensing, signal acquisition, and signal processing. Signal processing subsystem was designed with the aim of localizing damage utilizing elastic wave propagation in the interrogated structure. The embedded signal processing subsystem is realized in a field programmable gate array chip, which also implements a damage localization algorithm designed for creating damage maps that can indicate elastic wave reflection sites within the investigated structure. Elastic waves are generated and received using a prototype electronic system developed specially for this purpose. Piezoelectric transducers are arranged in networks with different geometrical configurations (strip, cross, and square). Elastic waves are excited by a five-cycle tone burst signal with carrier frequency of 220 kHz. The investigated structure is a simple isotropic panel made out of aluminum alloy. First, dispersion curves are computed on the basis of registered elastic wave signals. These are subsequently used in the damage localization process. The damage localization process utilizes the base antisymmetric A0 mode. This article presents results of experimental verification of the developed damage localization algorithm as well as results of damage localization by the embedded subsystem.