RU2284519C1 - Method for diagnosing of rail lengths of metal bridge and apparatus for effectuating the same - Google Patents

Abstract

FIELD: diagnosis of rail lengths of metal bridge.

SUBSTANCE: method involves continuously measuring longitudinal and transverse deformations of rail and rate of changing longitudinal and transverse deformations, said measurements being performed upon coming of train onto rail; starting acoustic signals receiving and detecting operations when rate of changing longitudinal deformation differs from zero, and ceasing said operations when rate of changing transverse deformation differs from zero; renewing acoustic signal receiving operation when rate of changing transverse deformation is equal to zero and ceasing said operation when rate of changing longitudinal deformation is equal to zero.

EFFECT: provision for obtaining of reliable control results and reduced volume of measurement information.

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Description

The invention relates to non-destructive testing and technical diagnostics by the acoustic emission method of railway rail lashes on a metal bridge structure.

A known method of controlling the quality of welded joints of rails, which consists in the fact that they weld the joint, cut the burr, register the acoustic emission signals when the weld is cooling, measure the count rate of the acoustic emission signals and judge the quality of the weld by its value. In addition, the control time is divided into intervals, in each of which the weld temperature decreases by 10% of the maximum temperature at the time of burr cutting, and the weld joint is rejected if the acoustic signal count exceeds the threshold value in at least one of the intervals (A.s No. 1629837, MKI 5 G 01 N 29/14, BI No. 7, 1991, adopted as an analogue);

The disadvantage of this method is the fact that it can only be used in welding control, but cannot be used in the quality control of rails laid in the path on a bridge structure. This significantly limits the scope of its use. In addition, the count rate of acoustic emission signals varies significantly and depends on many parameters, for example, the grade of steel from which the rails are made, the nature of the defect (crack, lack of penetration, etc.). As a result, the reliability of control during welding when using this method is low.

Known multi-channel acoustic emission diagnostic system of structures (RF Patent No. 2217741, MKI 7 G 01 N 29/14, BI No. 33, 2003), consisting of 1 ... n channels, each of which contains a series-connected acoustic transducer, a preamplifier, a filter, a main amplifier, a comparator, the output of which is connected to a timer, a pairing device, a digital-to-analog converter, the output of which is connected to a non-inverting input of the comparator, and also contains an analog-to-digital converter, the output of which is connected to the first random access memory input. In addition, the main amplifier in the system is programmable, and its output is connected to the inverting input of the comparator and the analog-to-digital converter, the output of the random access memory is connected to the first input of the signal processor, the output of which is connected to the interface device, and the output of the interface device is connected to the local network, which, in turn, is connected to a computer, the timer output is connected to the input of the control device, and the first output of the control device is connected to the input of the generator, the output to which is connected via a key to an acoustic transducer, the second output of the control device is connected to the control input of the random access memory, the third output of the control device is connected to the second input of the signal processor, and the control device is also capable of issuing a command to increase the response threshold, which is digital-to-analog the converter is installed at the input of the comparator.

In this device, channels 1 ... n allow registration and preliminary processing of acoustic emission signals. The disadvantage of this device is the inability to measure strains in the area of the investigated structure, in which acoustic transducers are installed. The lack of data on deformations and mechanical stresses in the design significantly reduces the reliability of the results of AE diagnostics.

Closest to the proposed solution is a method for diagnosing metal bridge structures, including receiving, recording and evaluating the parameters of acoustic emission signals at the time of loading the bridge metal structure, for example, by a passing train, digitizing acoustic signals, calculating the spectrum of acoustic signals from it, their preliminary processing, filtering interference, recording the time of arrival of acoustic signals and calculating the coordinates of developing defects from it. In addition, simultaneously with the registration of signals from acoustic transducers, dynamic deformation is recorded, and the main parameters of acoustic signals, the coordinates of developing defects and their spectral characteristics are recorded at the time the design reaches its maximum mechanical deformation (RF Patent No. 2240551. IPC 7 G 01 N 29 / 04. A method for diagnosing bridge metal structures and a device for its implementation / Stepanova L.N., Muraviev V.V., Kruglev V.M. et al., Priority dated June 20, 2001, adopted a prototype).

The disadvantage of this method is the following circumstance. The method includes receiving, recording and evaluating the parameters of acoustic emission signals, digitizing acoustic signals, calculating the spectrum of acoustic signals from it, pre-processing it, filtering interference, recording the time of arrival of acoustic signals and calculating the coordinates of developing defects from it, registering dynamic deformation when it reaches a maximum mechanical deformation of the structure. However, this method cannot be implemented when testing railway rail lashes due to the fact that when the train moves along the rail, high-level noise and interference occur. AE signals should be recorded not at the time of maximum deformation (as in the prototype), but at times when the rate of change of longitudinal deformation becomes different from zero. When the rate of change of the transverse deformation becomes nonzero, the acoustic signals are stopped, since powerful wheel shocks on the rail, noise and high-level noise occur. When the wheel leaves the rail, the rate of change of the transverse deformation becomes equal to zero, i.e. There are no wheel bumps on the rail, but there is longitudinal deformation, at this moment the reception of acoustic signals continues. Acoustic signals are stopped when the longitudinal strain is zero.

The closest in technical essence is a multi-channel acoustic emission device for the diagnosis of bridge metal structures, consisting of n blocks, each of which contains a channel consisting of a series-connected acoustic transducer, pre-amplifier, filter, as well as analog-to-digital transducer, random access memory and interface devices. In addition, in the first channel, the filter output is connected to a series-connected analog-to-digital converter, random access memory, signal processor and interface device, and it is also equipped in each block with a second channel consisting of a series-connected strain gauge, an analog converter, an analog-to-digital converter , a processor and an interface device, the outputs of the interface devices of the first and second channels of the unit being connected to the signal bus of the computer; which, in turn, is connected to a computer. Moreover, the second processor output of the second channel of the unit is connected to the second inputs of random access memory and the signal processor of the first channel, as well as to the input of the generator, the output of which is connected to a key, the output of which is connected to the acoustic transducer (RF Patent No. 2240551, IPC 7 G 01 N 29 / 04. A method for diagnosing bridge metal structures and a device for its implementation / Stepanova LN, Muravyov VV, Kruglov VM and others, priority of 06/20/2001, adopted as a prototype).

The main disadvantages of this device include:

- lack of filtering signals by deformations;

- a large flow of spurious AE signals, in connection with which the loss of useful information is possible;

- low reliability of information of AE signals at the time of passage of a train along a rail section containing a defect.

When developing the proposed method for diagnosing rail lashes on a bridge metal structure and a device for its implementation, the task was to increase the reliability of the monitoring results and reduce the amount of measurement information.

и в случае, если скорость изменения продольной деформации становится отлична от нуля, начинают прием и регистрацию акустических сигналов, прекращают прием акустических сигналов, когда скорость изменения поперечной деформации окажется отличной от нуля, прием акустических сигналов возобновляется, когда скорость изменения поперечной деформации равна нулю, и прекращается, когда продольная деформация равна нулю.The problem is solved due to the fact that in the proposed method for diagnosing rail lashes, a metal bridge, reception and registration of dynamic deformation and parameters of acoustic emission signals at the time of loading of a rail by a passing train are carried out, digitization of acoustic signals, calculation of the spectrum of acoustic signals from it, their preliminary processing, filtering interference, recording the time of arrival of acoustic signals and calculating the coordinates of developing defects from it. In addition, at the time of train collision with the rail, longitudinal and transverse deformations of the rail and the rate of change of longitudinal and transverse deformations are continuously measured

and if the rate of change of the longitudinal strain becomes non-zero, the reception and registration of acoustic signals are started, the reception of acoustic signals is stopped when the rate of change of the transverse strain is non-zero, the reception of acoustic signals is resumed when the rate of change of the transverse strain is zero, and stops when the longitudinal strain is zero.

The problem is also solved due to the fact that the multichannel acoustic emission device for diagnosing rail lashes of a metal bridge, consisting of n blocks, each of which contains a channel consisting of a series-connected acoustic transducer, pre-amplifier, filter, analog-to-digital converter, operational the storage device and the interface device, the signal processor, in the first channel, the filter output is connected to a series-connected analog-digital a converter, random access memory, a signal processor and a pairing device, and a second channel consisting of a load cell, an analog converter, an analog-to-digital converter, a processor and a pairing device, the outputs of the pairing devices of the first and second channels of the unit being connected to the computer signal bus, which, in turn, is connected to a computer, and the second processor output of the second channel of the block is connected to the second inputs of random access memory a signaling device and a signal processor of the first channel, as well as with the input of a generator, the output of which is connected to a key, the output of which is connected to an acoustic transducer. In addition, according to the invention, a second filter, a first and second comparators and a voltage reference are additionally introduced into the second channel, the output of the analog converter connected to the second filter and to the first input of the first comparator, the output of the second filter connected to the first input of the second comparator, the output of which is connected with the first processor input, the second processor input is connected to the second input of the second comparator, and the second input of the first comparator is connected to the reference voltage source, and the output of the first comparator coupled to a third input of the processor.

The proposed system in comparison with the existing acoustic emission system (RF Patent No. 2240551, IPC 7 G 01 N 29/04. Method for diagnosing bridge metal structures and device for its implementation / Stepanova LN, Muraviev VV, Kruglov V .M. Et al., Priority of June 20, 2001), it is possible to significantly increase the reliability of the control, since acoustic emission signals are recorded at a time when the rate of change of longitudinal deformations in the rail lane is non-zero, and measurements are taken at the moment when in the rail creates uniaxial tensile-compression deformation, i.e. practically no wheel bumps on the rail. Stop receiving acoustic signals when the rate of change of the transverse strain is nonzero, i.e. when powerful wheel bumps occur on the rail.

Figure 1 shows the time diagram of deformations explaining the work of the proposed method for diagnosing rails laid in the path on a bridge structure. Figure 2 shows the functional diagram of the information conversion unit. Figure 3 shows the timing diagram of deformations and control pulses that explain the collection of information in the proposed device. Figure 4 shows a rail with transverse and longitudinal load cells mounted on it.

A device that implements a method for diagnosing rail lashes on a bridge metal structure (figure 2), contains:

1 ... n are blocks;

2 - acoustic transducer;

3 - pre-amplifier;

4 - filter;

5, 11 - analog-to-digital converter;

6 - random access memory;

7, 13 - interface device;

8 - signal processor;

9 - strain gauge;

10 - analog converter;

12 - processor;

14 - computer signal bus;

15 - computer;

16 - generator;

17 - key

18 - filter;

19 - two-threshold comparator;

20 - a comparator;

21 is a voltage reference source.

The practical implementation of the proposed device that implements a method for diagnosing rail lashes on a bridge metal structure is performed according to known schemes using the following components:

- signal processor TMS320LC548; programmable logic integrated circuit of the MAX7000 EPM7192SOC160-7 family;

- random access memory UM628100; digital to analog converter TLC7528; operational amplifiers AD797, МС33282; analog-to-digital converters AD9260; ETHERNET NE8392C interface. Comparator type LM 311.

Their main characteristics are described in the following sources:

1. FPGA company ALTERA: design of signal processing devices - M .: DODEKA, 2000, p.18.

2. Internet sites of Texas Instruments-www.ti.com, Analog Devices-www.ad.com; Motorolla firms - www.motco.com; Altera firms - www.altera.com.

3. The system of circuit simulation MICRO-CAP5-M .: "SOLON", 1997.

4. Microcircuits for analog-to-digital conversion and multimedia. - M .: DODEKA, 1996, Issue 1, p. 214.

A multi-channel acoustic emission device for diagnosing rail lashes of a metal bridge (Fig. 2), consisting of n blocks, each of which contains a channel consisting of a series-connected acoustic transducer 2, pre-amplifier 3, filter 4, analog-to-digital converter 5, operational memory device 6, interface device 7, signal processor 8. In the first channel, the output of the filter 4 is connected to a series-connected analog-to-digital Converter 5, operational memory device 6, a signal processor 8 and a pairing device 7. The second channel consists of a series-connected load cell 9, an analog converter 10, an analog-to-digital converter 11, a processor 12 and a pairing device 13, the outputs of the pairing devices of the first (7) and second (13 ) the channels of the block are connected to the signal bus of the computer 14, which, in turn, is connected to the computer 15, and the second output of the processor 12 of the second channel of the block is connected to the second inputs of the random access memory 6 and the main processor 8 of the first channel, as well as with the input of the generator 16, the output of which is connected to the key 17, the output of which is connected to the acoustic transducer 2. In addition, the second filter 18, the first 19 and second 20 comparators and the reference voltage source are additionally introduced 21. Moreover, the output of the analog converter 10 is connected to the second filter 18 and to the first input of the first comparator 19. The output of the second filter 18 is connected to the first input of the second comparator 20, the output of which is connected to the first input of the processor 12, the second CPU 12 is coupled to move with the second input of the second comparator 20, and the second input of the first comparator 19 is connected to a reference voltage source 21, and the output of the first comparator 19 is connected to the third input of the processor 12.

The proposed method and device operate as follows.

First, before diagnosing rail lashes on a bridge metal structure, a rail lash is tested, which consists in determining the propagation velocity of ultrasonic pulses in the rail where the diagnostics are carried out. To do this, a command from the processor 12 of the second channel of unit 1 connects the key 17 to the acoustic transducer 2 and starts the generator 16, which gives a short pulse. In this case, the acoustic transducer 2 converts the pulse into an acoustic signal that propagates in the rail and is received by the acoustic transducers of the remaining blocks. The system measures the propagation time of the acoustic signal along the rail and calculates the propagation speed of the acoustic signal as

where a is the distance from the acoustic transducer operating in radiation mode to the acoustic transducer operating in reception mode; t is the propagation time of the acoustic signal from the acoustic transducer operating in the radiation mode to the acoustic transducer operating in the receiving mode.

Deformations in the rail are measured by the strain system. To do this, the longitudinal and transverse strain gauges are pre-installed on the rail, after which they are interrogated to determine the strain-free zero readings in the rail (the beginning of section A in figure 1). In this case, the design is completely unloaded. In the future, the calculation of deformations arising from the movement of the train is carried out relative to the zero reference.

Rails laid on a metal bridge are rigidly fastened together by side plates. When the train moves in front of it, an elastic longitudinal deformation is created by the moving train load. The design of the anti-theft rails after the passage of the train removes elastic longitudinal deformation (Railway track / T.G. Yakovleva, N.I. Karpuschenko, S.I. Klinov and others / Edited by T.G. Yakovleva - M .: Transport, 1999 , 405 p.).

Figure 1 shows the dependence of longitudinal deformations in the rail on time. The rail before running over the train experiences significant longitudinal deformations (end of section A and section B in FIG. 1). When the train hits the rail, where the strain gauges are installed, intense fluctuations in internal stresses occur, determined by the longitudinal and transverse deformations of the rail by the strain gauges (section C in Fig. 1). At the moment of contact of the wheel with the rail section, where acoustic emission transducers and strain gauges are installed, longitudinal and transverse strains and a large number of AE signals that are spurious are close to maximum values. After the passage of the train in the rail, the longitudinal stresses of the opposite sign gradually decrease (section D in FIG. 1).

The task of AE control during the passage of a train can be solved by processing large data flows of a noise signal to identify the internal fine structure of the signal in real time. However, solving such problems requires large powers of computing systems and a complete theory of AE signal generation in solids by various sources. Almost all signals from AE sources located inside the rail were received during time intervals B and D. The remaining recorded signals were associated with various noise sources and came mainly in time interval C (A.N. Seryoznov, L.N. Stepanova., VV Muraviev et al. Diagnostics of transport objects by acoustic emission method. - M.: Mashinostroenie, 2004, p. 351-358).

In figure 3, the letters A, B, C, D, E denote the time intervals of the passage of the train along the bridge structure. Time interval A corresponds to the moment the train starts to run onto the rail lash, during this interval the bridge structure under the tested rail lash is not sufficiently deformed and low logic levels at the outputs of the comparators 19 and 20. Acoustic signals are not allowed at this time. The time interval B corresponds to the approach of the train to the tested rail lash. In this case, the rate of change of the longitudinal strain becomes nonzero. At the output of the two-threshold comparator 19, a high logic level appears, allowing the reception of acoustic signals, and at the output of the comparator 20, a low logic level remains. The time interval C corresponds to the moment from the train entering the section (or rail section) where acoustic emission transducers and strain gauges of transverse deformations of the rail lash are installed, and until the train leaves this section. This interval is characterized by a high level of alternating transverse deformations, signals appear at the outputs of the comparators 19 and 20. The signals from the output of the comparator 20 are prohibited from receiving acoustic signals. The time interval D begins from the moment the train leaves the test rail lash and is characterized in that the rate of change of the transverse strain is zero. At the output of the comparator 20, a low logic level appears, and at the output of the comparator 19, a high logic level is received, allowing the reception of acoustic signals. The time interval E corresponds to the departure of the train from the bridge structure, longitudinal strains are equal to zero, and at the outputs of the comparators - low logic levels, the reception of acoustic signals is prohibited.

To increase the reliability of diagnosing rail lashes laid on a metal bridge, it is necessary to know exactly the location of the train relative to the diagnosed rail due to the large flow of AE signals at the time the train passes along the rail. A large number of spurious signals and high-amplitude noise caused by the passage of a train along a rail lash makes it practically impossible to digitize all signals from acoustic transducers. This is due to the limited memory capacity and speed of modern acoustic emission systems. The proposed diagnostic method allows to reduce the amount of measurement information and increase the reliability of the monitoring results due to the fact that the registration of acoustic signals is carried out not the entire period of time the train is on the bridge structure, but only at a certain point preceding the train's direct approach to the rail and immediately after the train leaves rail, when the rate of change of longitudinal deformation will be non-zero or the rate of change of transverse deformation is zero.

становится отличной от нуля, и фильтр 18 пропускает такой сигнал, который заставляет срабатывать компаратор 20. На фиг.3 показана диаграмма работы фильтра 18 и компараторов 19 и 20 в зависимости от входного сигнала. Сигнал с компаратора 20 поступает на управляющий вход микропроцессора 12, который переводит на время Δt сигнальный процессор 8 в режим считывания и обработки информации из оперативного запоминающего устройства 6, запрещая прием новых акустических сигналов, и одновременно сбрасывает компаратор 20 в исходное состояние. Через время Δt микропроцессор 12 считывает информацию с компаратора 20. Если компаратор сработал, то цикл повторяется, а если на выходе компаратора нет сигнала, то микропроцессор 12 подает команду сигнальному процессору 8, который разрешает аналого-цифровому преобразователю 5 запись в оперативное запоминающее устройство 6. Таким образом, обеспечивается непрерывная запись информации с акустического преобразователя 2 первого канала блока 1 в оперативное запоминающее устройство 6. В те периоды времени, когда скорость изменения продольной деформации в рельсовой плети становится отличной от нуля, а скорость изменения поперечной деформации равна нулю (моменты до захода поезда на рельсовую плеть и момент схода поезда с рельсовой плети, обозначенные на фиг.3 как интервалы В и D), осуществляется запись всех сигналов акустической эмиссии, поступающих с акустического преобразователя 2. Сигнальный процессор 8 рассчитывает их основные параметры (амплитуда, спектр, энергия, скорость нарастания переднего фронта, длительность, активность и т.д.). Сигнальный процессор 8 рассчитывает спектральные характеристики сигналов акустической эмиссии и записывает их в оперативное запоминающее устройство 6. В оперативном запоминающем устройстве 6 хранится информация о спектральных характеристиках сигналов акустической эмиссии. Центральный процессор компьютера 15 формирует команду, по которой сигнальный процессор 8 считывает информацию из оперативного запоминающего устройства 6 и через устройство сопряжения 7 информация пересылается по общей шине данных 14.When the rail lash is loaded by the train running, the acoustic signals are amplified in the pre-amplifiers 3, then they are filtered in the filter 4, which allows to remove low-frequency noise, after which the signals are fed to the input of an analog-to-digital converter 5, which digitizes them. Simultaneously with the digitization of acoustic emission signals, a continuous measurement of mechanical strains in the area of the location of this acoustic transducer is carried out. In this case, the output of the strain gauge 9 mounted on the rail lash is connected to the input of the analog converter 10. From the output of the analog converter 10, the signal is fed to the input of the analog-to-digital converter 11 of the second channel of the unit for measuring deformations. Then, a digitized signal containing information about the mechanical deformations of the rail lash is fed to the input of the microprocessor 12. To increase the reliability of diagnosis, a filter 18 is introduced into the second channel, to which an analog signal from the analog converter 10 is supplied, the output of the filter 18 is connected to the input of the comparator 20, the output of which connected to the control input of microprocessor 12. A two-threshold comparator 20 is also introduced, the first input of which receives a signal from analog converter 10, and is connected to the second input the output of the reference voltage source 21. If the rate of change of longitudinal deformations becomes nonzero, then the filter 18 does not pass the signal from the analog converter 10. In this case, the comparator 20 does not work, and when the reference voltage of the source 21 is exceeded (Fig. 1), a two-threshold comparator is triggered 19. The microprocessor 12 issues a command to the signal processor 8, which controls the acoustic channel 1 of the unit 1 of the device, allowing the reception and processing of acoustic signals. When the train wheels hit a controlled rail, the rate of change of lateral deformation

becomes non-zero, and the filter 18 passes a signal that causes the comparator 20. The figure 3 shows a diagram of the filter 18 and the comparators 19 and 20 depending on the input signal. The signal from the comparator 20 is fed to the control input of the microprocessor 12, which transfers the signal processor 8 to the mode of reading and processing information from the random access memory 6 for a time Δt, prohibiting the receipt of new acoustic signals, and at the same time resets the comparator 20 to its original state. After a time Δt, the microprocessor 12 reads the information from the comparator 20. If the comparator has worked, then the cycle repeats, and if there is no signal at the output of the comparator, the microprocessor 12 sends a command to the signal processor 8, which allows the analog-to-digital converter 5 to write to the random access memory 6. Thus, a continuous recording of information from the acoustic transducer 2 of the first channel of unit 1 to the random access memory 6 is provided. In those time periods when the rate of change of the longitudinal strain the train lane becomes nonzero, and the rate of change of the transverse deformation is zero (moments before the train enters the rail lash and the moment the train leaves the rail lash, indicated in Fig. 3 as intervals B and D), all acoustic emission signals are recorded coming from the acoustic transducer 2. The signal processor 8 calculates their main parameters (amplitude, spectrum, energy, rise rate of the leading edge, duration, activity, etc.). The signal processor 8 calculates the spectral characteristics of the acoustic emission signals and writes them to the random access memory 6. The random access memory 6 stores information about the spectral characteristics of the acoustic emission signals. The central processor of the computer 15 generates a command by which the signal processor 8 reads information from the random access memory 6 and through the interface device 7 the information is sent via a common data bus 14.

в рельсовой плети становится отличной от нуля, то начинается прием акустических сигналов, их оцифровка, локализация, определение спектральных характеристик и т.д. Прием акустических сигналов сразу же прекращается, когда колесо заходит на рельс, возрастает скорость изменения поперечных деформаций и становится отличной от нуля. При этом возникают шумы и помехи большого уровня и регистрация акустических сигналов в этот момент невозможна. Прием акустических сигналов возобновляется, когда колесо уходит с рельса и скорость изменения поперечных деформаций равна нулю. При этом уровень шумов и помех невысокий и система принимает, оцифровывает и обрабатывает акустические сигналы. Когда поезд уходит с рельса, то продольные деформации становятся равными нулю и снова прекращается прием акустических сигналов.Thus, if the rate of change of the longitudinal strain

in the rail lash becomes different from zero, then the reception of acoustic signals begins, their digitization, localization, determination of spectral characteristics, etc. Acoustic signals immediately cease when the wheel enters the rail, the rate of change of transverse deformations increases and becomes non-zero. In this case, noise and noise of a large level arise and the registration of acoustic signals at this moment is impossible. Acoustic signal reception resumes when the wheel leaves the rail and the rate of change of lateral deformations is zero. In this case, the level of noise and interference is low and the system receives, digitizes and processes acoustic signals. When the train leaves the rail, the longitudinal strains become equal to zero and the reception of acoustic signals ceases again.

The proposed device in comparison with the prototype has a higher reliability, since the registration of signals occurs at the most informative points in time (immediately before the train enters the rail and after the train leaves the rail lash).

Claims (2)

1. A method for diagnosing rail lashes of a metal bridge, including receiving, recording and evaluating dynamic deformation and parameters of acoustic emission signals when the rail is loaded, for example, by a passing train, digitizing acoustic signals, calculating the spectrum of acoustic signals from it, their preliminary processing, filtering interference, recording time the arrival of acoustic signals and calculating from it the coordinates of developing defects, characterized in that when the train hits the rail, the longitudinal e and lateral deformations of the rail and the rate of change of longitudinal and transverse deformations, and the reception and registration of acoustic signals begin at a rate of change of longitudinal deformation other than zero, and stop at a rate of change of transverse deformation other than zero and resume the reception of acoustic signals at a rate of change of transverse deformation equal to zero, and stop at a rate of change of longitudinal strain equal to zero. 2. A multi-channel acoustic emission device for diagnosing rail lashes of a metal bridge, consisting of n blocks, each of which contains a channel consisting of a series-connected acoustic transducer, pre-amplifier, filter, analog-to-digital converter, random access memory and signal processor, device pairing, in the first channel, the filter output is connected to series-connected analog-to-digital Converter, random access memory a property, a signal processor and an interface device, and a second channel, consisting of a series-connected load cell, an analog converter, an analog-to-digital converter, a processor, and an interface device, the outputs of the interface devices of the first and second channels of the unit being connected to the signal bus of the computer, which in turn connected to a computer, and the second processor output of the second channel of the block is connected to the second inputs of random access memory and the signal processor of the first channel, as well as with the input of the generator, the output of which is connected to a key, the output of which is connected to an acoustic transducer, characterized in that the second channel further comprises a second filter, first and second comparators and a voltage reference source, the output of the analog transducer connected to the second filter and with the first input of the first comparator, the output of the second filter is connected to the first input of the second comparator, the output of which is connected to the first input of the processor, the second input of the processor is connected to the second input the second comparator, and the second input of the first comparator is connected to a reference voltage source, and the output of the first comparator is connected to the third input of the processor.

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