Towards improved damage location using acoustic emission

Abstract

The acoustic emission technique is a passive non-destructive testing technique that has significant potential for use as a structural health monitoring technique for many large-scale structures, allowing continuous global monitoring. The location capability of the acoustic emission technique is its most beneficial attribute; however, the location accuracy can often be limited in complex materials and structures. This article discusses recent advances in the location of acoustic emission signals. The key sources of errors are identified as signal arrival time measurement and processing algorithm limitations. A series of strategies for reducing the effects of both causes of error are presented. Additionally, the results of a case study are used to demonstrate a novel mapping technique for acoustic emission source location of fatigue crack signals in an aircraft landing gear component. Improvements in location accuracy of up to 87.5% were observed when compared with standard location calculation algorithms.

A Bayesian Approach for Localization of Acoustic Emission Source in Plate-Like Structures

“…The increasing emphasis on integrity of critical structures such as aircrafts urges the needs to monitor structures in situ and real-time to detect damages at an early stage to prevent catastrophic failure. In general, an effective online structural health monitoring system should consist of two major components: active monitoring and passive monitoring [1,2]. Active monitoring needs both actuators and sensors to evaluate the damage of a structure, while passive monitoring uses only sensors to "listen" to the acoustic emission (AE) wave signals emitted by internal or external sources such as propagating cracks or impacts.…”

Failure Assessment and Evaluation of Damage Development and Crack Growth in Polymer Composites Via Localization of Acoustic Emission Events: A Review

“…On the other hand, research is being done with fiber optic sensors 7 and other transduction methods. 4 The basic challenge of monitoring AE is to distinguish between transient (burst-type) and continuous signals.…”

“…This is due to the fact that the AE signals are released from mechanically activated sources (i.e., structures under stress). 4 To make use of AE, the sensors have to be able to detect and record minute surface displacements caused when the wave incidents upon the surface of the investigated test coupon or part. A peculiar feature of AE waves is that they travel in solid plates as Lamb-waves.…”

“…Next we shall report on selected techniques because the comprehensive overview on the various methods (e.g., location refining algorithms [11][12][13][15][16][17] ) and techniques (e.g., sensor arraying) are beyond the scope of this review. 4,11,17 Our intention is to show recent developments in studying the fracture, damage development, and crack growth in polymeric systems. It should be borne in mind that for the above-listed tasks, the location of the AE is just the tool.…”

Acoustic Emission Source Location in I Girder Based on Experimental Study and Lamb Wave Propagation Simulation

“…c) comparison of the measured (∆ti,mea) and calculated (∆ti,calc) arrival time difference is used to determine the point of best agreement between the measured and calculated arrival times. The minimisation of the objective function X [5] is expressed in Eq. (1) and (2):…”