List of publications in 2014, in which our employees participated:
Sergey Elizarov, Vera Barat, Arkady Shimansky. Nonthreshold Acoustic Emission Data Registration Principles. Proceedings of the 31st Conference of the European Working Group on Acoustic Emission, Dresden, 03-05 September 2014 https://www.ndt.net/article/ewgae2014/papers/we3b4.pdf (full text)
Abstract
Traditional way of acoustic emission (AE) signals registration is a threshold method. AE impulse is registered when acoustic signal exceeds preset threshold, and impulse standard parameters (amplitude, arrival time, rise time, duration and others) are counted in on-line mode. Threshold method is simple and stable one, but has a set of drawbacks. First of all, threshold value is set by operator, thus it could be set incorrectly due to human factor. Secondly, AE - impulse arrival time is calculated as time of threshold crossing, this value differs from real one, what leads to imprecision in AE sources location. Thirdly, threshold method considers acoustic emission as an impulse process with stationary noise background, this model does not suit to continuous emission or non-stationary noise cases. Intelligent nonthreshold method, based on theory of signal detection, may be considered as alternative to threshold method for AE impulse detection. In this approach AE impulses are detected as fragments of continuous data flow, which has specific waveform and frequency characteristics. Method implementation involves usage of adaptive and matched filtering and change point detecting algorithms in on-line mode. Intelligent method allows to evaluate impulses arrival times and detect impulses with amplitudes below noise level with help of adaptive filtering. High time accuracy AE - impulses detecting provides precise AE - sources location and criteria estimation, which enhances AE - testing method validity. By means of digital signal processing impulse and continuous signal products are extracted. AE signal continuous component is analyzed separately. Continuous component analysis allows to identify leaks, technological noise and pre-destruction continuous emission. Currently, due to the high level of circuit technology development nonthreshold algorithm of AE data acquisition can be implemented in hardware.
Sergey Elizarov, Arkady Shimansky, Vera Barat. Intelligent Acoustic Emission System. Proceedings of the 31st Conference of the European Working Group on Acoustic Emission, Dresden, 03-05 September 2014 https://www.ndt.net/article/ewgae2014/papers/p4.pdf (full text)
Abstract
Acoustic emission (AE) - testing method has a set of standing out special features, distinguishing it from other testing methods. It's a passive control method with high defects-detecting sensitivity, that does not need scanning of object surface and provides remote object testing with defects location on distances from meters to hundreds of meters. AE - method drawbacks are: high acoustic noise level induced by work of testing equipment, complexity of defects parameters estimation, high labor intensity and requirements to qualification of personnel, performing AE - testing. Nowadays different schools of sciences perform investigations for further development of AE - testing method, its possibilities enhancing, accuracy improving and practical field enlargement. Current article presents intellectual AE - system principles, such a system has upgraded AE - testing process by means of automation and intellectualization of functions, commonly performed by operator. Intellectual AE - system has automation of next functions: sampling rate assignment for correct time and frequency resolution, adaptive filtering of AE - signals for their efficient detecting against technological equipment noise background, and automated data registration without setting of threshold, sceto and other parameters by operator. Data registration procedure uses non-threshold statistical method of AE - impulses extraction on the basis of acoustic stationary noise properties changing. By means of digital signal processing pulse and continuous signal products are extracted, continuous product allows to identify leaks, technological noise and pre-destruction continuous emission. Intelligent AE system can improve the accuracy and reliability of the AE testing. Precise detection of acoustic emission impulses improves the AE sources location result, and precise location provides the precise AE source evaluation. Automatic determination of the setting parameters allows us to reduce the human factor influence on the results of the AE testing.
Alexander Sagaidak, Vladimir Bardakov, Sergey Elizarov, Denis Terentyev. The Use of Acoustic Emission Method in the Modern Construction. Proceedings of the 31st Conference of the European Working Group on Acoustic Emission, Dresden, 03-05 September 2014 https://www.ndt.net/article/ewgae2014/papers/fr1a3.pdf (full text)
Abstract
The method of acoustic emission is a very effective NDT method, which is widely used in nuclear power, oil, gas and chemical industry, mining and health care. The method of acoustic emission is widely used and standardized in many countries. In the modern construction of the method of acoustic emission finds wide application in non-destructive testing and evaluating the condition of building structures. The goals of this report are review of the regulatory standards and perspective investigations on the application of the acoustic emission method in modern construction and present results of several scientific researches on this topic. The main provisions of the report will be presented in accordance with the following content: current state of standards and guidelines on acoustic emission in the construction field, comparative analysis and prospects; the results of research conducted by authors in the Research, Design and Technological Institute for Concrete and Reinforced Concrete named after Gvozdev and practical experience of application of the obtained results. Civil construction buildings form a class of the test objects, for which the estimates of the structural integrity by acoustic emission method can become a successful commercial application.
Vasil'ev I.E., Matvienko Ju.G., Ivanov V..I., Elizarov S.V. Method of identifying sources of acoustic emission signals arising from degradation of material, cracking and structural failure. Russian patent №2569078 (2015). eLibrary ID: 37459314
Abstract
Field: physics. Substance: method includes measuring maximum pulse amplitude, the number of emissions and the duration of signal pulses, after which acoustic emission signal sources are identified based on said measurements. Effect: high reliability of identifying acoustic emission signal sources.
D. A. Terentyev, Yu. S. Popkov. Determination of the parameters of the dispersion curves of Lamb waves with the use of the Hough transform of the spectrogram of an AE signal. Russian Journal of Nondestructive Testing. January 2014, Volume 50, Issue 1, pp 19-28. DOI: 10.1134/S1061830914010082. eLibrary ID: 21877427
Abstract
A method for the recognition of dispersion curves on the spectrogram of acoustic-emission signals has been developed based on the Hough transform. The method was successfully tested in an experiment using a Hsu-Nielsen source. It has been determined that the suggested method can determine the distance from the source of a signal, even when the signal arrives only at one acoustic emission transducer. This enables one to perform AE testing only with one-sided access to any dimensional object or when there is a sufficiently large distance between transducers, when an AE signal reaches only one of them.