Acoustic emission source location and damage detection in a metallic structure using a graph-theory-based geodesic pproach

Gangadharan, R and Prasanna, G and Bhat, MR and Murthy, CRL and Gopalakrishnan, S (2009) Acoustic emission source location and damage detection in a metallic structure using a graph-theory-based geodesic pproach. In: Smart materials structures, 18 (11).

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Abstract

A geodesic-based approach using Lamb waves is proposed to locate the acoustic emission (AE) source and damage in an isotropic metallic structure. In the case of the AE (passive) technique, the elastic waves take the shortest path from the source to the sensor array distributed in the structure. The geodesics are computed on the meshed surface of the structure using graph theory based on Dijkstra's algorithm. By propagating the waves in reverse virtually from these sensors along the geodesic path and by locating the first intersection point of these waves, one can get the AE source location. The same approach is extended for detection of damage in a structure. The wave response matrix of the given sensor configuration for the healthy and the damaged structure is obtained experimentally. The healthy and damage response matrix is compared and their difference gives the information about the reflection of waves from the damage. These waves are backpropagated from the sensors and the above method is used to locate the damage by finding the point where intersection of geodesics occurs. In this work, the geodesic approach is shown to be suitable to obtain a practicable source location solution in a more general set-up on any arbitrary surface containing finite discontinuities. Experiments were conducted on aluminum specimens of simple and complex geometry to validate this new method.

Item Type:	Journal Article
Publication:	Smart materials structures
Publisher:	Institute Of Physics
Additional Information:	Copyright for this article belongs to Institute Of Physics.
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	09 Dec 2009 09:50
Last Modified:	19 Sep 2010 05:52
URI:	http://eprints.iisc.ac.in/id/eprint/24906

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