List of publications in 2012, in which our employees participated:
Vera Barat, Sergey Elizarov, Irina Bolokhova and Evgeniy Bolokhov. Application of ICI Principle for AE Data Processing. Journal of Acoustic Emission, 30, 2012, pp. 124-136 https://www.ndt.net/article/jae/papers/30-124.pdf (full text)
Abstract
During AE data processing, it is often necessary to determine the change points of parameters. The most important problems are arrival time detection and AE data segmentation. The first-arrival time of acoustic emission (AE) signal is very important parameter, which is used for event location and identification. At present there are many advanced arrival time determination methods, which significantly increase accuracy of estimation in comparison with traditional threshold crossing method. However, advanced methods have several disadvantages connected with algorithm parameters selection. Arrival time estimation algorithms are based on a calculation of several statistical parameters within a sliding time window. The time-window length is often chosen empirically by the operator. When criteria for window length selection are undefined an incorrect length selection is possible, as well as incorrect AE signal arrival time definition. This paper describes the method based on intersection of confidence interval (ICI) principle. This method allows one to select time parameters optimally and in automatic mode. Application of ICI principle increases the accuracy and reliability of first-arrival time estimation. The problem of segmentation data arises in connection with the necessity to identify the data. Specifically the definition in the data stream of time intervals corresponding to different stages of the observed processes.
Vera Barat, Sergey Elizarov, Irina Kovalchuk, Evgeniy Bolokhov. Application of ICI Principle for the First-Arrival Time Correction. Proceedings of the 30th European Conference on Acoustic Emission Testing & 7th International Conference on Acoustic Emission EWGAE 30 / ICAE 7, Granada, 12-15 September 2012, pp. 506-515 https://www.ndt.net/article/ewgae2012/content/papers/44_Barat_Rev1.pdf (full text)
Abstract
The first-arrival time of acoustic emission (AE) signal is very important parameter, which is used for event location and identification. At present there are many advanced arrival time determination methods, which significantly increase accuracy of estimation in comparison with traditional threshold crossing method. However, advanced methods have several disadvantages connected with algorithm parameters selection. Arrival time estimation algorithms are based on a calculation of several statistical parameters within a sliding time window. The time-window length is often chosen empirically by the operator. When criteria for window length selection are undefined an incorrect length selection is possible, as well as incorrect AE signal arrival time definition. This paper describes the method based on intersection of confidence interval (ICI) principle. This method allows to select time parameters optimally and in automatically mode. Application of ICI principle results in increasing of accuracy and reliability of first-arrival time estimation.
Sergey V. Elizarov, Alexander L. Alyakritskiy, Vassily G. Koltsov , Vera A. Barat, Pavel N. Trofimov. Portable NDT Instrument “Uniscope”. Proceedings of the 30th European Conference on Acoustic Emission Testing & 7th International Conference on Acoustic Emission EWGAE 30 / ICAE 7, Granada, 12-15 September 2012, pp. 711-715 https://www.ndt.net/article/ewgae2012/content/papers/13_Elizarov_Rev3.pdf (full text)
Abstract
The multipurpose NDT device "Uniscope" is presented below. This instrument has two wide band analog inputs for the connection of different transducers and two universal digital inputs for external measurement units. In the basic configuration "Uniscope" is a full-function 2-channel AE-system. As an option, the instrument can be equipped with parametric measuring blocks to register temperature, pressure, stress values and etc., leak testing software, estimating the amount of leakage, and vibration analysis elements. Such universality is reached through using various external measuring units to be connected to the common computing device, provided with generic software with the modern friendly interface. The instrument is made as a portable single-unit construct, with an operating keyboard, placed on the front face, and color LCD-display to visualize data. "Uniscope" has long operating time from two built-in rechargeable batteries. Storage of large bulk of data is available on readily accessible information media. The environmental protection and extended temperature range let to use "Uniscope" under difficult weather conditions.
Alexander Sagaidak, Sergey Elizarov, Nina Reshetilova. Experience in application of acoustic emission method for estimation of building construction condition. Proceedings of the 30th European Conference on Acoustic Emission Testing & 7th International Conference on Acoustic Emission EWGAE 30 / ICAE 7, Granada, 12-15 September 2012, pp. 679-685 https://www.ndt.net/article/ewgae2012/content/papers/45_Sagaidak_Rev1.pdf (full text)
Abstract
In this paper the experience in practical application of the acoustic emission (AE) method for estimation of the crane trestle condition at the Sayano-Shushenskaya Hydroelectric Plant after an accident, and the perspectives of the AE method for estimation of the building construction condition have been considered. To estimate the crane trestle condition at the Sayano-Shushenskaya Hydro, cyclic loadings of massive reinforced concrete constructions of the crane trestle were used. The Kaiser effect was applied for estimating stresses operating in the construction. The technique for estimation of the building construction condition has been developed and approved, which allows for defining the occurrence of structural damage beforehand. Results of the studies conducted is useful in monitoring of the critical structures.
Denis Terentyev, Yuri Borodin. Use of Lamb Wave Dispersion Curve Extraction from AE Signal Spectrogram for Determination of Distance to AE Source. Proceedings of the 30th European Conference on Acoustic Emission Testing & 7th International Conference on Acoustic Emission EWGAE 30 / ICAE 7, Granada, 12-15 September 2012, pp. 217-221 https://www.ndt.net/article/ewgae2012/content/papers/43_Terentyev_Rev1.pdf (full text)
Abstract
Case of AE testing of gas pipeline is described. Owing to the large value of acoustic signal attenuation and the large distance between sensors, signals from AE sources arrived only to one of the nearest sensors. This made it impossible to carry out usual location of sources based on the arrival time differences. At the same time the Lamb wave dispersion curves were observed on a number of AE signal spectrograms. Therefore, the technique of Lamb mode dispersion curves extraction from AE signal spectrograms by using the Hough transform was applied. Application of the offered technique on these objects appeared successful. The sources co-ordinates were calculated, and then, with the use of the known attenuation coefficient the effective amplitudes of signals were calculated, that enables AE classification. Furthermore, the use of dispersion curves analysis allowed for determining an average value of the wall thickness between AE source and AE sensor.