Acoustic Emission, A Non-Destructive Technique - An Overview

Abstract

Abstract: With increasing number of structures approaching their design life, it became very important for the designers and operators to develop innovative Structural Health Monitoring (SHM) techniques. Structural Health Monitoring (SHM) is the process of monitoring or assessing the condition of a structure in order to gather information on its current state by tracking variables like vibration, strain, stress and other physical phenomena, responses and conditions. It seeks to assist in nondestructive evaluations aimed to detect location and extent of damage, calculate the remaining life of an asset and predict upcoming accidents. Acoustic Emission technique is a passive monitoring approach based on the detection of elastic waves in structural components generated by damages, such as the initiation and propagation of cracks, the failure of steel wires, and the failure of bonds. Its primary goal is to detect, locate, and assess the intensity of damage in a non-invasive way, both when the structure is in-service and during load tests. Its application in SHM (Structural Health Monitoring) started much later compared to other fields, such as the aerospace industry. The interest has increased because elastic waves generated by damages propagate throughout the structure; therefore, it is possible to remotely detect damages in areas that are not easily accessible to visual inspections and direct measurements