Владимир Качанов - Academia.edu (original) (raw)

Papers by Владимир Качанов

Measurement Techniques

Problems that arise in ultraacoustic contactless testing of articles across a nonresonant air gap... more Problems that arise in ultraacoustic contactless testing of articles across a nonresonant air gap are considered. Results of the development of high-efficiency, wideband, low-frequency, ultraacoustic piezoelectric transducers for contactless testing of articles made of composite materials are presented.

Measurement Techniques, 2012

Problems of ultrasonic noise-immune testing of complexly structured cast-iron articles are consid... more Problems of ultrasonic noise-immune testing of complexly structured cast-iron articles are considered. It is shown that the extraction of informative echo signals from noise and interference requires, in addition to the fulfillment of optimal signal-filtering conditions, the use of flexible multifunctional equipment for ultrasonic testing that allows formation of various signals, flexible variation of their parameters, and application of numerous radio-engineering operations to signals for adapting the parameters of the instrumentation to the characteristics of a tested object.

Russian Journal of Nondestructive Testing, 2010

The basic propositions of spatiotemporal signal processing as applied to the problems of ultrason... more The basic propositions of spatiotemporal signal processing as applied to the problems of ultrasonic testing of complex-structure articles with a high attenuation of acoustic signals are considered. Different algorithms of extracting informational echo signals from white and structural noise during multichannel spatiotemporal signal processing are studied.

Measurement Techniques - MEAS TECH-ENGL TR, 2009

A new method of measuring the velocity of acoustic waves in large-size concrete products is consi... more A new method of measuring the velocity of acoustic waves in large-size concrete products is considered, based on the use of eigenfrequency methods. It is shown that it is necessary to monitor the velocity at several points on the surface of the article with subsequent calculation of the degree of cross correlation of the experimental and theoretical spectral characteristics for each measurement.

Nondestructive Testing and Evaluation - NONDESTRUCT TEST EVAL, 2001

This article describes the methodology of signal processing in ultrasonic nondestructive testing ... more This article describes the methodology of signal processing in ultrasonic nondestructive testing of materials with structural heterogeneities. Reflections of probing signal from these heterogeneities entail appearance of a peculiar interference a structural noise witb the same spectral composition as the probing signal. Therefore, it is hard to overcome these interferences. The article also discusses the methodology of recognising the signal on the background of structural noise in ultrasonic non-destructive testing using spatially dispersed transducers, focusing antennae, antennae with synthesised aperture, and the most efficient method spatialtemporal signal processing, which suggests multichannel reception of probing signal combined with optimal signal filtration in each channel.

Russian Journal of Nondestructive Testing, 2011

It is shown that the spatial distribution of the acoustic field of a broadband transducer may inf... more It is shown that the spatial distribution of the acoustic field of a broadband transducer may influence the degree of distortion of ultrasonic signals. The principle for forming a uniform acoustic-field distribution within the directivity characteristic of a low-frequency broadband transducer based on the chosen topology of a mosaic transducer is proposed. The comparative spatiotemporal characteristics of mosaic broadband transducers

Russian Journal of Nondestructive Testing, 2010

The well-known method of focusing ultrasonic signals to a point implemented using phased antenna ... more The well-known method of focusing ultrasonic signals to a point implemented using phased antenna arrays is considered as applied to problems of tomography of products manufactured from complexly structured materials. The features of applying broadband ultrasonic complexly modulated signals in phased antenna arrays and the limits of applicability of this method in constructing an image of a reflecting surface are

Russian Journal of Nondestructive Testing

The problem of the creation of stacked (mosaic and composite) broadband transducers that simultan... more The problem of the creation of stacked (mosaic and composite) broadband transducers that simultaneously provide a broad band and a high electroacoustic transduction efficiency is ana lyzed. The mosaic technology is shown to be optimal for the practical implementation of ultrasonic broadband low frequency electroacoustic transducers. Being functionally flexible, the mosaic tech nology allows the development of numerous variants of electroacoustic transducers for the solution of different ultrasonic testing problems and, first of all, for the undistorted transduction of signals.

Russian Journal of Nondestructive Testing

It is shown that structural noise (SN) and informative echo signals can be decorrelated not only ... more It is shown that structural noise (SN) and informative echo signals can be decorrelated not only during ultrasonic flaw detection for extracting signals from SN but also in ultrasonic structuroscopy, in which reflections from a structure are not a disturbance but yield information on the structure of the tested material. Using the technique of wavelet processing of SN signals proposed in this study, signals of acoustic emission that appear during kinetic indentation of metals are analyzed in order to determine physicomechanical characteristics of metals.

Russian Journal of Nondestructive Testing

Methods for extracting ultrasonic echo signals from interferences (electroacoustic interference a... more Methods for extracting ultrasonic echo signals from interferences (electroacoustic interference and structural noise) correlated with a probing signal are studied in detail. These methods are based on the frequency separation of the spectra of the informative signal and noise. Frequency-separation methods involving lock-in signal detection are considered. Various aspects of using a lock-in detector in flaw detection and tomography of complexly structured articles are analyzed. Examples of applying the frequency decorrelation of signals in ultrasonic testing of large old cast bronze bells of the Ivan the Great Bell Tower in the Moscow Kremlin and large bells of the Cathedral of Christ the Savior in Moscow are considered.

Russian Journal of Nondestructive Testing

The main concepts of the theory of optimal signal processing as applied to tasks of ultrasonic te... more The main concepts of the theory of optimal signal processing as applied to tasks of ultrasonic testing of articles with high integral damping of acoustic vibrations are considered. The conditions for ensuring the optimal transfer coefficient of the receiving section of an ultrasonic flaw detector's electroacoustic channel are formulated. The requirements for the characteristics of broadband piezoelectric transducers aimed at the insurance of undistorted transmission of ultrasonic signals are formulated.

Russian Journal of Nondestructive Testing

Problems of ultrasonic noise-immune testing of complexly structured cast-iron articles are consid... more Problems of ultrasonic noise-immune testing of complexly structured cast-iron articles are considered. It is shown that the extraction of informative echo signals from noise and interference requires, in addition to the fulfillment of optimal signal-filtering conditions, the use of flexible multifunctional equipment for ultrasonic testing that allows formation of various signals, flexible variation of their parameters, and application of numerous radio-engineering operations to signals for adapting the parameters of the instrumentation to the characteristics of a tested object.

Measurement Techniques

Problems of acoustic monitoring of extensive concrete building structures are considered. The dis... more Problems of acoustic monitoring of extensive concrete building structures are considered. The disadvantages of existing methods of measuring the thickness of concrete articles are demonstrated. A new resonance-multiplicative method is proposed that increases measurement accuracy and reliability. Results are provided for a test model of a thickness meter.

Russian Journal of Nondestructive Testing

Broadband low frequency mosaic ultrasonic piezoelectric transducers with apertures comparable wit... more Broadband low frequency mosaic ultrasonic piezoelectric transducers with apertures comparable with acoustic wavelengths, which are designed as sets of acoustically coupled piezoelectric elements of different heights, are considered. Examples of small aperture broadband mosaic trans ducers and their production technology are presented.

Russian Journal of Nondestructive Testing

These and subsequent articles present the results of the studies of interference resistant method... more These and subsequent articles present the results of the studies of interference resistant methods and devices for ultrasonic testing of extended items made of complexly structured materials. The presented results are based on the radio-engineering R & D that have been conducted for over 30 years by the Department of Electronic Devices of the Moscow Power Engineering Institute. The studies are concurrently focused on the development of methods for separating echo signals from white and structural noise, on the application of complexly modulated signals, on the development of spatial and temporal methods for processing signals, on the development of broadband mosaic transducers, and on the design of multifunctional devices for ultrasonic testing. The necessity of such a comprehensive approach to ultrasonic testing is substantiated in this article by analysis of the problems of ultrasonic testing of complexly structured items with strong integral attenuation of ultrasound.

Indian Journal of Science and Technology, 2015

Indian Journal of Science and Technology, 2015

Russian Journal of Nondestructive Testing, 2010

The features of algorithms for identifying the configurations of reflecting objects (points, sphe... more The features of algorithms for identifying the configurations of reflecting objects (points, spheres, planes, cylinders, etc.) in ultrasonic tomography of complexly structured concrete products are considered. The results of a practical solution to the problem of recognizing a pattern and deter mining the coordinates of a flat reflector using ultrasonic phased antenna arrays are presented for the example of applying the algorithm of focusing to a plane.

Measurement Techniques, 2008

Problems of acoustic monitoring of extensive concrete building structures are considered. The dis... more Problems of acoustic monitoring of extensive concrete building structures are considered. The disadvantages of existing methods of measuring the thickness of concrete articles are demonstrated. A new resonance-multiplicative method is proposed that increases measurement accuracy and reliability. Results are provided for a test model of a thickness meter.

Russian Journal of Nondestructive Testing

It is shown that the quality of transformation of ultrasonic signals in a broadband transducer is... more It is shown that the quality of transformation of ultrasonic signals in a broadband transducer is affected by not only the amplitude-frequency but also the spatial characteristics of broadband probes. To evaluate the quality of transformation of ultrasonic broadband signals, integral spatiotemporal characteristics of a broadband probe are introduced, viz., the correlation field distribution and the correlation directivity characteristic. The experimental correlation spatiotemporal characteristics of a mosaic low-frequency broadband transducer are presented. Keywordsultrasound–broadband low-frequency piezoelectric transducer–mosaic transducer–directivity characteristic–correlation field distribution–correlation directivity characteristic

Measurement Techniques

Problems that arise in ultraacoustic contactless testing of articles across a nonresonant air gap... more Problems that arise in ultraacoustic contactless testing of articles across a nonresonant air gap are considered. Results of the development of high-efficiency, wideband, low-frequency, ultraacoustic piezoelectric transducers for contactless testing of articles made of composite materials are presented.

Measurement Techniques, 2012

Problems of ultrasonic noise-immune testing of complexly structured cast-iron articles are consid... more Problems of ultrasonic noise-immune testing of complexly structured cast-iron articles are considered. It is shown that the extraction of informative echo signals from noise and interference requires, in addition to the fulfillment of optimal signal-filtering conditions, the use of flexible multifunctional equipment for ultrasonic testing that allows formation of various signals, flexible variation of their parameters, and application of numerous radio-engineering operations to signals for adapting the parameters of the instrumentation to the characteristics of a tested object.

Russian Journal of Nondestructive Testing, 2010

The basic propositions of spatiotemporal signal processing as applied to the problems of ultrason... more The basic propositions of spatiotemporal signal processing as applied to the problems of ultrasonic testing of complex-structure articles with a high attenuation of acoustic signals are considered. Different algorithms of extracting informational echo signals from white and structural noise during multichannel spatiotemporal signal processing are studied.

Measurement Techniques - MEAS TECH-ENGL TR, 2009

A new method of measuring the velocity of acoustic waves in large-size concrete products is consi... more A new method of measuring the velocity of acoustic waves in large-size concrete products is considered, based on the use of eigenfrequency methods. It is shown that it is necessary to monitor the velocity at several points on the surface of the article with subsequent calculation of the degree of cross correlation of the experimental and theoretical spectral characteristics for each measurement.

Nondestructive Testing and Evaluation - NONDESTRUCT TEST EVAL, 2001

This article describes the methodology of signal processing in ultrasonic nondestructive testing ... more This article describes the methodology of signal processing in ultrasonic nondestructive testing of materials with structural heterogeneities. Reflections of probing signal from these heterogeneities entail appearance of a peculiar interference a structural noise witb the same spectral composition as the probing signal. Therefore, it is hard to overcome these interferences. The article also discusses the methodology of recognising the signal on the background of structural noise in ultrasonic non-destructive testing using spatially dispersed transducers, focusing antennae, antennae with synthesised aperture, and the most efficient method spatialtemporal signal processing, which suggests multichannel reception of probing signal combined with optimal signal filtration in each channel.

Russian Journal of Nondestructive Testing, 2011

It is shown that the spatial distribution of the acoustic field of a broadband transducer may inf... more It is shown that the spatial distribution of the acoustic field of a broadband transducer may influence the degree of distortion of ultrasonic signals. The principle for forming a uniform acoustic-field distribution within the directivity characteristic of a low-frequency broadband transducer based on the chosen topology of a mosaic transducer is proposed. The comparative spatiotemporal characteristics of mosaic broadband transducers

Russian Journal of Nondestructive Testing, 2010

The well-known method of focusing ultrasonic signals to a point implemented using phased antenna ... more The well-known method of focusing ultrasonic signals to a point implemented using phased antenna arrays is considered as applied to problems of tomography of products manufactured from complexly structured materials. The features of applying broadband ultrasonic complexly modulated signals in phased antenna arrays and the limits of applicability of this method in constructing an image of a reflecting surface are

Russian Journal of Nondestructive Testing

The problem of the creation of stacked (mosaic and composite) broadband transducers that simultan... more The problem of the creation of stacked (mosaic and composite) broadband transducers that simultaneously provide a broad band and a high electroacoustic transduction efficiency is ana lyzed. The mosaic technology is shown to be optimal for the practical implementation of ultrasonic broadband low frequency electroacoustic transducers. Being functionally flexible, the mosaic tech nology allows the development of numerous variants of electroacoustic transducers for the solution of different ultrasonic testing problems and, first of all, for the undistorted transduction of signals.

Russian Journal of Nondestructive Testing

It is shown that structural noise (SN) and informative echo signals can be decorrelated not only ... more It is shown that structural noise (SN) and informative echo signals can be decorrelated not only during ultrasonic flaw detection for extracting signals from SN but also in ultrasonic structuroscopy, in which reflections from a structure are not a disturbance but yield information on the structure of the tested material. Using the technique of wavelet processing of SN signals proposed in this study, signals of acoustic emission that appear during kinetic indentation of metals are analyzed in order to determine physicomechanical characteristics of metals.

Russian Journal of Nondestructive Testing

Methods for extracting ultrasonic echo signals from interferences (electroacoustic interference a... more Methods for extracting ultrasonic echo signals from interferences (electroacoustic interference and structural noise) correlated with a probing signal are studied in detail. These methods are based on the frequency separation of the spectra of the informative signal and noise. Frequency-separation methods involving lock-in signal detection are considered. Various aspects of using a lock-in detector in flaw detection and tomography of complexly structured articles are analyzed. Examples of applying the frequency decorrelation of signals in ultrasonic testing of large old cast bronze bells of the Ivan the Great Bell Tower in the Moscow Kremlin and large bells of the Cathedral of Christ the Savior in Moscow are considered.

Russian Journal of Nondestructive Testing

The main concepts of the theory of optimal signal processing as applied to tasks of ultrasonic te... more The main concepts of the theory of optimal signal processing as applied to tasks of ultrasonic testing of articles with high integral damping of acoustic vibrations are considered. The conditions for ensuring the optimal transfer coefficient of the receiving section of an ultrasonic flaw detector's electroacoustic channel are formulated. The requirements for the characteristics of broadband piezoelectric transducers aimed at the insurance of undistorted transmission of ultrasonic signals are formulated.

Russian Journal of Nondestructive Testing

Problems of ultrasonic noise-immune testing of complexly structured cast-iron articles are consid... more Problems of ultrasonic noise-immune testing of complexly structured cast-iron articles are considered. It is shown that the extraction of informative echo signals from noise and interference requires, in addition to the fulfillment of optimal signal-filtering conditions, the use of flexible multifunctional equipment for ultrasonic testing that allows formation of various signals, flexible variation of their parameters, and application of numerous radio-engineering operations to signals for adapting the parameters of the instrumentation to the characteristics of a tested object.

Measurement Techniques

Problems of acoustic monitoring of extensive concrete building structures are considered. The dis... more Problems of acoustic monitoring of extensive concrete building structures are considered. The disadvantages of existing methods of measuring the thickness of concrete articles are demonstrated. A new resonance-multiplicative method is proposed that increases measurement accuracy and reliability. Results are provided for a test model of a thickness meter.

Russian Journal of Nondestructive Testing

Broadband low frequency mosaic ultrasonic piezoelectric transducers with apertures comparable wit... more Broadband low frequency mosaic ultrasonic piezoelectric transducers with apertures comparable with acoustic wavelengths, which are designed as sets of acoustically coupled piezoelectric elements of different heights, are considered. Examples of small aperture broadband mosaic trans ducers and their production technology are presented.

Russian Journal of Nondestructive Testing

These and subsequent articles present the results of the studies of interference resistant method... more These and subsequent articles present the results of the studies of interference resistant methods and devices for ultrasonic testing of extended items made of complexly structured materials. The presented results are based on the radio-engineering R & D that have been conducted for over 30 years by the Department of Electronic Devices of the Moscow Power Engineering Institute. The studies are concurrently focused on the development of methods for separating echo signals from white and structural noise, on the application of complexly modulated signals, on the development of spatial and temporal methods for processing signals, on the development of broadband mosaic transducers, and on the design of multifunctional devices for ultrasonic testing. The necessity of such a comprehensive approach to ultrasonic testing is substantiated in this article by analysis of the problems of ultrasonic testing of complexly structured items with strong integral attenuation of ultrasound.

Indian Journal of Science and Technology, 2015

Indian Journal of Science and Technology, 2015

Russian Journal of Nondestructive Testing, 2010

The features of algorithms for identifying the configurations of reflecting objects (points, sphe... more The features of algorithms for identifying the configurations of reflecting objects (points, spheres, planes, cylinders, etc.) in ultrasonic tomography of complexly structured concrete products are considered. The results of a practical solution to the problem of recognizing a pattern and deter mining the coordinates of a flat reflector using ultrasonic phased antenna arrays are presented for the example of applying the algorithm of focusing to a plane.

Measurement Techniques, 2008

Problems of acoustic monitoring of extensive concrete building structures are considered. The dis... more Problems of acoustic monitoring of extensive concrete building structures are considered. The disadvantages of existing methods of measuring the thickness of concrete articles are demonstrated. A new resonance-multiplicative method is proposed that increases measurement accuracy and reliability. Results are provided for a test model of a thickness meter.

Russian Journal of Nondestructive Testing

It is shown that the quality of transformation of ultrasonic signals in a broadband transducer is... more It is shown that the quality of transformation of ultrasonic signals in a broadband transducer is affected by not only the amplitude-frequency but also the spatial characteristics of broadband probes. To evaluate the quality of transformation of ultrasonic broadband signals, integral spatiotemporal characteristics of a broadband probe are introduced, viz., the correlation field distribution and the correlation directivity characteristic. The experimental correlation spatiotemporal characteristics of a mosaic low-frequency broadband transducer are presented. Keywordsultrasound–broadband low-frequency piezoelectric transducer–mosaic transducer–directivity characteristic–correlation field distribution–correlation directivity characteristic