NDTnet 1998 Aug, Vol.3 No.8

Abstract

This paper describes a new instrument for the detection and localization of Acoustic Emission (AE) sources AEBIL (Acoustic Emission BInary Localizer), meeting the requirements for long-term structural integrity monitoring in an operating plant environment. AEBIL is designed to identify and locate concentrated AE sources in the presence of a high rate of spatially scattered AE events, a typical condition encountered in on-line monitoring of operating plant components. The system uses a limited number of conventional piezoelectric transducers, with innovative signal acquisition and conditioning modules, simplified AE processing procedures and correlation of AE with plant operating parameters. AE sources location is restricted to the axial coordinate in the case of elongated components. Real-time source location and screening are thus achieved; the amount of diagnostically significant data to be stored, transferred and examined turns out to be limited.The main processing steps are as -follows:


• acquisition and binary conversionof the AE signal (fig. 1).simultaneously on all channels (12 transducers maximum);
• double time correlations among three binary time sequences generated by each preselected triplet of transducers;
• identification and screening of localized AE sources by processing the distribution of delay time couples (T₂₁ ,T₃₁) generated by each transducer triplet.

The long-term performance and reliability of the system have been assessed by in-plant tests, on high temperature power plant components steam headers and steamline sections) in different operating conditions (steady load, load variations, startup/shutdown transient) and, finally, by over one year of continuous monitoring of different items in two ENEL power plants. Part of this work has been carried in the frame of BRITE-EURAM Project 6056 "SIMON" with the financial support of the UE Commission.

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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