NDTnet 1998 Aug, Vol.3 No.8

Abstract

During the last decade, Acoustic Emission has been widely accepted as a well established technique for both development and routine inspection of Composite Structures. This was achieved due to the advances [1] in AE instrumentation, as well as the evolution of methods for AE data interpretation. This paper is concerned with the latter and demonstrates the use of Pattern Recognition techniques for the identification of Signature of Acoustic Emission signals emitted from Composite Structures.The proposed method [2] consists of procedures for descriptors selection, data clustering and, most important, of techniques to validate the resulting partitions. The three previously mentioned essential steps for the application of the proposed pattern recognition technique in AE are presented and representative results from various composite structures, ranging from model specimens to GFRP pressure vessels and storage tanks are discussed.

The figure on the right shows thecumulative hits of the resulted classesof AE signals vs. the applied low. The figure clearly indicates the variousstages of damage initiation andevolution from each failure mechanism encountered in the material. The methodology enables the characterisation of damage severity by calculating the ratio between hits from the different signal classes.

The results prove the great help the method provides to the AE analyst in order to discover the statistical nature of both AE descriptors and signals, as well as to make useful correlation with the source of emission. Finally, the possibility of coupling the proposed method with existing data bases from field testing and/or other artificial intelligence techniques is discussed.

The economic balance in inspection

References
1. Sotirios J. Vahaviolos, in NDT, eds. D. Van Hemelrijck & A.Anastassopoulos, Balkema 1996, 101-115.
2. A. A. Anastassopoulos, T. P. Philippidis, J. of Acoustic Emission, VoL 13, Noa 112, 1995, 11-21.

Abstract Source:
Book of Abstracts, 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN: 87-986898-0-00

Full-Text Source:
Proceedings of the 7th European Conference on Non-Destructive Testing, 26-29 May 1998, ISBN:

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