Experimental Investigation of Crack Detection and Quantification Using PWAS Array

Abstract

Crack detection and size estimation are two key functionalities of a structural health monitoring algorithm. An experiment of crack detection in an aerospace grade aluminum sheet metal alloys was designed using an array of piezoelectric wafer active sensors (PWAS). Gaussian-distribution based damage mapping algorithm was used for analyzing the guided wave signals. Since multiple modes of Lamb waves often complicate the guided wave scattering, this can pose a significant challenge for an algorithm’s functionality. Mode rejection using appropriate tuning of the PWAS was used to selectively excite a single Lamb wave mode. In this case, symmetric Lamb waves were excited in the structure. A pitch-catch experimental mode was utilized. The crack was detected, localized, and the crack size was estimated