Vladimir K. Kachanov ¹, Igor V. Sokolov ¹, Alexey A. Sinitsyn ¹, Maksim B. Fedorov ¹

Affiliations
1 National Research University, Moscow Power Engineering Institute,Electrical Engineering Faculty, Moscow, RU

Abstract

It is shown that to improve the accuracy of Ultrasonic (US) thickness measurements of the large-sized products made of polymeric composite materials it is required to use Phase-Shift Keyed (PSK) Signals, known from Radio Engineering, and to determine echo signal time delay by the maximum of compressed PSK pulse. In order to improve the measurement accuracy US PSK Huffman encoding signals (M-signals) should be used in the continuous repetition mode, providing simultaneously high measurement accuracy and the greatest possible control sensitivity for a given period of repetition of probing pulses.

Keywords

Phase-Shift Keyed Signals, Polymeric Composite Materials, Measurement Accuracy, Ultrasonic Thickness Measurement

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Vladimir K. Kachanov ¹, Igor V. Sokolov ¹, Alexey A. Sinitsyn ¹, Maksim B. Fedorov ¹, Michael A. Karavaev ¹, Roman V. Kontsov ¹

Affiliations
1 National Research University, Moscow Power Engineering Institute, Electrical Engineering Faculty, Moscow, RU

Abstract

The results of analysis of the possibilities to use Complex-Modulated radio pulses as probing signals in US flaw detection are given. It is shown that the application of Complex-Modulated echo signals in the receiving path optimal filters improves the basic parameters of the echo control method – sensitivity and resolution capability, and, in presence of white noise and not correlated interference, generally increases the reliability of the testing method.

Keywords

Complex-Modulated Signals, Electro acoustic Pickup, Frequency-Modulated Pulse, Optimal Filtering, Phase- Shift Keyed Signal, US Flaw Detection

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Vladimir K. Kachanov ¹, Igor V. Sokolov ¹, Alexey A. Sinitsyn ¹, Maksim B. Fedorov ¹, Michael A. Karavaev ¹

Affiliations
1 Moscow Power Engineering Institute (National Research University), Russia

Abstract

Background/Objectives: The use of simple radio-technical processing of signals – synchronous detection – in the ultrasonic testing of products with large frequency-dependent attenuation of ultrasound is considered. Methods: The use of radar in the ultrasonic flaw detection methods allows for control of objects with a high level of attenuation of ultrasonic vibrations in a material. Findings: It is demonstrated that synchronous detection increases the accuracy of echo signal temporal position measurement and increases the reliability of US testing in the presence of narrowband interference and the correlation with the probing signal of the electroacoustic pickup. Improvements: The use of synchronous detection will significantly increase the sensitivity and noise immunity of the ultrasound equipment used to control the complex structural materials with high attenuation of ultrasound, such as concrete, cast iron, plastic, etc.

Keywords

Ultrasonic Flaw Detection, Synchronous Detection, Optimal Filtering, Complex-Modulated Signals, Electroacoustic Pickup.

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Vladimir K. Kachanov ¹, Igor V. Sokolov ¹, Alexey A. Sinitsyn ¹, Roman V. Kontsov ¹

Affiliations
1 Moscow Power Engineering Institute (National Research University), Russia

Abstract

Background/Objectives: The article discusses problems of isolating signals from the structural noise correlated with a sounding signal using the ultrasonic echo method of measuring the thickness of large items with complex structure. Methods: The article demonstrates that in addition to spatial decorrelation of the bottom signal and the interference correlated with it, it is possible to use algorithmic decorrelation by using phased arrays and the signal processing algorithm which searches for the reflecting planes. Findings: Preliminary spatial correlation of the “useful” signal from structural noise is a condition for signal isolation. Measurement of the thickness of large, complexly structured concrete items is used to demonstrate that the use of the “focusing on a plane” algorithm will improve the bottom signal/structural noise ratio and thus increase the measurable thickness of the concrete items. Applications/ Improvements: The use of the algorithm, "focusing on the plane" in modern thickness gauges and scanners applied for monitoring concrete structures can significantly increase the reliability and accuracy of defect detection.

Keywords

Focusing on a Spot, Focusing on a Plane, Structural Noise, Tomography, Ultrasonic Phased Array.

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