RU2710080C1 - Device for determining position of small-size metal inclusions in articles from composite materials - Google Patents

Abstract

FIELD: measuring equipment.SUBSTANCE: invention relates to non-destructive testing methods and can be used for detection of small-sized metal inclusions in articles made from polymer composite materials, as well as in any non-conductive materials. Device includes first to fourth amplifiers (1, 4, 5, 9), first to second synchronous detectors (2, 3), two-channel analogue-to-digital converter (6), processing unit (7), indicator (8) and induction transducer (11). Input of first amplifier (1) is connected to induction transducer (11), and its output is connected to the first inputs of the first and the second synchronous detectors (2, 3). Output of the first synchronous detector (2) is connected to the input of second amplifier (4). Output of the second synchronous detector (3) is connected to the input of third amplifier (5). Outputs of the second and third amplifiers (4, 5) are connected to inputs of the two-channel analogue-to-digital converter (6); and its output is connected to processing unit (7) input. First output of processing unit (7) is connected to the second inputs of the first and second synchronous detectors (2, 3), its second output is connected to the input of fourth amplifier (9), and its third output is connected to the input of indicator (8). Output of fourth amplifier (9) is connected to the input of induction transducer (11). Switching device (10) is connected between induction transducer and first amplifier. Induction transducer (11) includes exciting inductance coil (11.1) and measuring inductance coils, outputs of which are connected to corresponding inputs of switching device (10) and which are concentrically located inside exciting inductance coil (11.1); number of measuring coils of induction transducer and their radii are determined proceeding from assumed depth of occurrence and sizes of metal inclusions and necessary error of location of small-sized metal inclusions. Input of induction transducer (11) is input of exciting inductance coil (11.1).EFFECT: high reliability of detecting small-sized metal inclusions.1 cl, 10 dwg

Description

Technical field

The invention relates to non-destructive testing methods and can be used to detect small metallic inclusions (MMB) with sizes from 0.1 to 2 mm in products from polymer composite materials (PCM), as well as in any non-conductive materials.

State of the art

The technical feasibility of this invention is that it marks the coordinates of each small metal inclusion (if the small metal inclusion is not too close to one another).

A device is known (patent No. 2593155, IPC B03C 1/00, 02/10/2016, Bull. No. 4) according to which the content of small particles is determined in fluids. The disadvantage of this device is that it is able to detect only magnetically active particles.

A device is also known (patent No. 2366982, IPC G01V 3/11, 05/27/2008, bull. No. 15), which is the closest analogue of the present invention, designed to detect metal objects in various environments. The disadvantage of this device is that it captures only the presence of rather large objects (weapons, gold jewelry), and the accuracy of the position of the object is recorded only approximately. This is the closest analogue.

Today, there is an urgent need for the detection of small metallic inclusions in PCM products, in the development of a device for diagnosing the technical condition of real complex spatial structures, which can be applied in practice for a wide range of PCM objects.

The disadvantage of this device is that it captures only the presence of rather large objects - weapons, gold jewelry. The location accuracy is recorded with a large error, insufficient for the process of detecting small metal inclusions in PCM.

The prototype error is approximately 30 mm. The required detection error of small metal inclusions in the PCM should not exceed 5 mm.

Fundamentally, an approach to reducing the error in detecting the location of small-sized metallic inclusions in PCM became possible with the development of mathematical modeling software (see, for example, abstracts of the joint user conference ANSYS and “PLM Ural” - 2014), the emergence of new technologies in the field of electronics, control, and informatics (see, for example, the XXVIII International Scientific and Technical Conference "Modern Technologies in the Problems of Control, Automation and Information Processing" - 2018).

Studies have shown that this problem can be solved by several non-destructive testing (ND) methods, for example, X-ray, thermal or ultrasound.

However, this did not lead to the desired results, due to a number of reasons:

1. Modern radiation monitoring systems allow the detection of metal elements in real time in the material of the product. The sensitivity of the control depends on the density of the material and the thickness of the translucent object, its shape and orientation, the mode and conditions of transmission, the method of recording control results. The disadvantages of this control method are the need for human radiation protection, low mobility, high cost of technical equipment, etc.

2. A promising method of NDT and diagnostics is a rapidly developing thermal NDT, where information about the parameters of the object is carried by the temperature of its surface, the values of which are mainly determined by the parameters of the excitation of the thermal field, changes in the thermophysical, geometric characteristics of the test object and defect, etc. The disadvantages of this control method are the need for exposure to thermal radiation on the product, which is not always acceptable for PCM products. In addition, thermal control, with all its advantages, has limitations on the detection of defects at a large depth.

3. A fairly popular NK method is ultrasonic NK. However, it is not always able to detect small defects in PCM structures. (see, for example, AO Kuznetsov. Detection of small-sized metal inclusions in products from composite materials by the eddy-current method. In the book: TestMat. Main trends, directions and prospects for the development of non-destructive testing methods in the aerospace industry: abstract. X All-Russian conf., Moscow, February 9, 2018.S. 162-166.)

SUMMARY OF THE INVENTION

The invention is aimed at reducing the detection error of small-sized metal inclusions in PCM in real conditions of production and operation.

That is, ultimately, the invention is aimed at improving the safety of operation of complex potentially hazardous structures.

The technical result achieved when using the claimed group is to increase the reliability of detection of small metallic inclusions by introducing several measuring inductors in the induction transducer and, as a result, rejecting the resonant circuits used in the prototype, since the induction converter system includes the use of resonant circuits unable to provide the required accuracy of detection of small metal opinions.

где Т_ок - максимальная толщина исследуемого объекта, и измерительные катушки индуктивности, выходы которых соединены с соответствующими входами коммутатора и которые концентрично расположены внутри возбуждающей катушки индуктивности; количество измерительных катушек индукционного преобразователя и их радиусы определены, исходя из предполагаемой глубины залегания и размеров металлических включений и необходимой погрешности определения местоположения малоразмерных металлических включений, а вход индукционного преобразователя является входом возбуждающей катушки индуктивности.The technical result is achieved due to the fact that the device for determining the position of small metal inclusions in products made of composite materials, including the first to fourth amplifiers; first - second synchronous detectors; two-channel analog-to-digital converter; processing unit, indicator and induction converter; where the input of the first amplifier is connected to the induction converter, and its output is connected to the first inputs of the first and second synchronous detectors; the output of the first synchronous detector is connected to the input of the second amplifier; the output of the second synchronous detector is connected to the input of the third amplifier; the outputs of the second and third amplifiers are connected to the inputs of a two-channel analog-to-digital converter; and its output is with the input of the processing unit; the first output of the processing unit is connected to the second inputs of the first and second synchronous detectors, its second output is connected to the input of the fourth amplifier, and its third output is connected to the indicator input; the output of the fourth amplifier is connected to the input of the induction converter; a commutator connected between the induction converter and the first amplifier is introduced, while the induction converter includes an exciting inductor whose radius R _is selected taking into account the maximum thickness of the composite product from the condition

where T _ok - the maximum thickness of the investigated object, and measuring inductors, the outputs of which are connected to the corresponding inputs of the switch and which are concentrically located inside the exciting inductor; the number of measuring coils of the induction converter and their radii are determined based on the estimated depth and size of the metal inclusions and the necessary error in determining the location of small metal inclusions, and the input of the induction converter is the input of the exciting inductor.

где

- минимальное возможное значение удельной электропроводимости малоразмерных металлических включений в контролируемом композитном материале, а μ₀ - магнитная постоянная вакуума.The technical result is enhanced due to the fact that the processing unit includes a microprocessor and a harmonic oscillation generator associated with its output, while the frequency ω of the harmonic oscillator is selected from the condition

Where

- the minimum possible value of electrical conductivity of small-sized metal inclusions in a controlled composite material, and μ ₀ is the magnetic constant of vacuum.

Brief Description of the Drawings

The invention and the possibility of achieving a technical result will be more clear from the following description with reference to the position of the drawings, where:

FIG. 1 shows a block diagram of a device;

FIG. 2 shows a coil control zone;

FIG. 3 shows a sample of RMB;

FIG. 4 shows small metal inclusions;

FIG. 5 shows a device;

FIG. 6 is a graph of experimental results;

FIG. 7 is a graph of the error in determining the location and size of metal inclusions.

FIG. 8 shows a diagram of an experiment;

FIG. 9 shows a photo of an experiment;

FIG. 10 shows the results of the experiment.

In the above figures, the following notation:

1 - the first amplifier;

2 - the first synchronous detector;

3 - second synchronous detector;

4 - second amplifier;

5 - the third amplifier;

6 - two-channel analog-to-digital converter;

7 - a signal processing unit based on a microprocessor, including a generator of harmonic oscillations of frequency ω;

8 - indicator;

9 - the fourth amplifier;

10 - switch;

11 - induction converter;

11.1 - exciting inductor of an induction converter;

11.2 - the first measuring inductor of the induction transducer;

11.3 - second measuring inductor of the induction transducer;

11.4 - third measuring inductor of the induction transducer;

N - "N-th" measuring inductor of an induction transducer;

12 - object of control - a product from composite materials (with small metal inclusions);

13 - generated electromagnetic radiation;

14 - received electromagnetic radiation;

15 - PCM sample with artificially introduced small-sized metal inclusions;

16 - small metal inclusion with a size of 0.1 mm;

17 - small metal inclusion size of 0.3 mm;

18 - small metal inclusion size of 0.5 mm;

19 - small metal inclusion size 0.8 mm;

20 - small metal inclusion with a size of 1 mm;

21 - small metal inclusion size of 1.3 mm;

22 - small metal inclusion with a size of 1.5 mm;

23 - small metal inclusion with a size of 2 mm;

24 - induction converter;

25 - device;

R is the radius of the exciting coil (in the prototype);

Z _to - control zone;

R _In - the radius of the exciting inductor of the induction Converter;

R _11.2 is the radius of the first measuring inductor of the induction transducer;

R _11.3 is the radius of the second measuring inductor of the induction transducer;

R _11.4 is the radius of the third measuring inductor of the induction transducer;

Z _k4 - control zone of the third receiving resonant circuit of the induction converter;

T _ok - the thickness of the object of control;

h ₁ - distance from the measurement surface equal to 3 mm;

h ₂ - distance from the measurement surface equal to 12 mm;

h ₃ - distance from the measurement surface equal to 20 mm;

h ₄ - distance from the measurement surface equal to 27 mm;

δ is the measurement error;

PKM - polymer composite material;

ADC - analog-to-digital converter.

Preferred Embodiment

All electronic components used are built on the basis of standard microprocessor circuits and microprocessor assemblies with reprogrammable memory devices. The outputs of the induction converter 11 are connected in series with standard elements: a commutator 10 (see P. Horowitz, W. Hill. The art of circuitry. - M .: Mir, 1993, v. 1), amplifier 1, which are used variable amplifiers current (see P. Horowitz, W. Hill. The art of circuitry. - M .: Mir, 1993, v. 1, p. 185) whose output is connected to synchronous detectors 2, 3 (see P. Horowitz, U Hill, The Art of Circuit Engineering. - M .: Mir, 1993, v. 1, p. 237), the outputs of which are connected respectively with amplifiers 4, 5 (see P. Horowitz, W. Hill. Art of Circuit Engineering and -. M .: Mir, 1993, Vol 1, p 185) and inputs of a two-channel analog-to-digital converter (ADC) 6, which is applied as a firm ADC ANALOG DEVICES (AD 974) description... The output of the ADC 6 is connected to the inputs of the processing unit based on microprocessor 7, which uses Atmel mega 16 * microprocessor from Atmel, which has a harmonic oscillator (see Internet description), the outputs of which are connected to indicator 8. The liquid crystal indicators can serve as indicators DATA VISION indicators (see PLATAN Electronic Components 1999, p. 20) or another means for displaying information. The outputs of the processing unit 7 are respectively connected to the reference inputs of synchronous detectors 2, 3 and the input of the power amplifier 9 (see P. Horowitz, W. Hill. The art of circuitry. - M.: Mir, 1993, v. 1, p. 253 ), the output of which is connected to the input of the induction converter 11.

A device for determining the position of small metal inclusions in products made of composite materials includes the first and fourth amplifiers 1, 4, 5, 9; first - second synchronous detectors 2, 3; two-channel analog-to-digital converter 6; processing unit 7, indicator 8 and induction converter 11.

The input of the first amplifier 1 is connected to the induction converter 11, and its output is connected to the first inputs of the first and second synchronous detectors 2, 3. The output of the first synchronous detector 2 is connected to the input of the second amplifier 4. The output of the second synchronous detector 3 is connected to the third amplifier 5 The outputs of the second and third amplifiers 4, 5 are connected to the inputs of the two-channel analog-to-digital converter 6; and its output is with the input of the processing unit 7. The first output of the processing unit 7 is connected to the second inputs of the first and second synchronous detectors 2, 3. Its second output is connected to the input of the fourth amplifier 9, and its third output is to the input of the indicator 8.

The output of the fourth amplifier 9 is connected to the input of the induction converter 11. Between the induction converter 11 and the first amplifier 1, a switch 10 is connected.

где Т_ок - максимальная толщина исследуемого объекта, и измерительные катушки индуктивности 11.2-11.4,, выходы которых соединены с соответствующими входами коммутатора 10 и которые концентрично расположены внутри возбуждающей катушки индуктивности 11.1. Количество измерительных катушек индукционного преобразователя и их радиусы определены, исходя из предполагаемой глубины залегания и размеров металлических включений и необходимой погрешности определения местоположения малоразмерных металлических включений. Вход индукционного преобразователя 11 является входом возбуждающей катушки индуктивности 11.1. Блок обработки 7 включает микропроцессор и связанный с его выходом генератор гармонических колебаний при этом частота ω генератора гармонических колебаний выбрана из условия

где

- минимальное возможное значение удельной электропроводимости малоразмерных металлических включений в контролируемом композитном материале, а μ₀ - магнитная постоянная вакуума.The induction converter 11 includes a drive inductor 11.1, the radius of which R _{in is} selected taking into account the maximum thickness of the product from a composite material from the condition

where T _ok - the maximum thickness of the investigated object, and measuring inductors 11.2-11.4 ,, the outputs of which are connected to the corresponding inputs of the switch 10 and which are concentrically located inside the exciting inductor 11.1. The number of measuring coils of the induction converter and their radii are determined based on the estimated depth and size of the metal inclusions and the necessary error in determining the location of small metal inclusions. The input of the induction converter 11 is the input of the exciting inductor 11.1. Processing unit 7 includes a microprocessor and a generator of harmonic oscillations connected with its output, while the frequency ω of the harmonic oscillator is selected from the condition

Where

- the minimum possible value of electrical conductivity of small-sized metal inclusions in a controlled composite material, and μ ₀ is the magnetic constant of vacuum.

Above the surface of the object of control 12 is a driving coil 11.1 connected to the output of the amplifier 9, the input of which is connected to the output of the processing unit 7, forming rectangular pulses of harmonic oscillations, from the measuring coils 11.2, 11.3, 11.4 of different radii R _11.2 > R _11.3 > R _11.4 signals enter the input of the switch 10, through the amplifier 1, enter the inputs of synchronous detectors 2, 3, the outputs of which are connected to amplifiers 4, 5, the outputs of which are connected to the inputs of the two-channel ADC 6, the output of which is connected to the inputs of the processing unit 7. If the detected signal from the switching fixed all measuring coils 11.2, 11.3, 11.4, this means that small-sized metallic inclusion is disposed in the proximal zone (Z _k11.4) (top) and its coordinates are determined from the coil signal of 11.4 (as more precise). If the signals come from coils 11.2, 11.3, then the inclusion is located in the middle zone (further than the control zone Z to _11.4 ) and the coordinates correspond to the signal of coil 11.3, etc. The number of zones (i.e. the number of coils) is determined by the thickness of the tested object from the composite and technological requirements.

(Т_ок - толщина исследуемого объекта), частоту генератора гармонических колебаний выбирают из условия

где

- минимальное значение удельной электропроводимости металлических частиц металлов, которые могут иметь место при производстве исследуемого композита (для определенности можно принять

). Выбор частоты из вышеприведенного условия уменьшает погрешность влияния удельной электропроводимости металлических частиц на сигналы измерительных катушек (см. Герасимов В.Г., Покровский А.Д., Сухоруков В.В. Неразрушающий контроль. В 5 кн. Кн. 3. Электромагнитный контроль: Практ. пособие; под ред. В.В. Сухорукова. - М.: Высш. шк., 1992. - 312 с.: ил.). Зона чувствительности катушки индуктивности (т.е. пространство, в котором существует ее магнитное поле) представляет собой яйцеобразное тело вращения, осевой разрез половины которого представлен на Фиг. 2. Размер зоны контроля Z_к, т.е. величина расстояния от катушки до поверхности объекта контроля - зависит от радиуса катушки Z_к ≈ 4÷5R. Устройство снабжено несколькими измерительными катушками разного радиуса, сигналы которых зависят от наличия и положения металлических частиц и через схемы обработки поступают на индикаторный блок.The technical effect obtained in solving this problem, which consists in determining the position of a small metal inclusion in the PCM under study, is achieved by the fact that in a known device containing a microprocessor, including a harmonic oscillation generator, exciting and measuring coils, a signal processing unit of the measuring coil, an indicator where the output of the harmonic oscillator is connected to the exciting coil, the measuring coil is connected to the signal processing unit, to the output of which th indicator is attached, the radius R _in the exciting coil is selected from the condition

(T _ok - the thickness of the investigated object), the frequency of the harmonic oscillation generator is selected from the condition

Where

- the minimum value of the electrical conductivity of metal particles of metals that may occur in the production of the studied composite (for definiteness, you can take

) The choice of frequency from the above condition reduces the error of the influence of the electrical conductivity of metal particles on the signals of the measuring coils (see Gerasimov V.G., Pokrovsky A.D., Sukhorukov V.V. Nondestructive testing. In 5 book, book 3. Electromagnetic testing: Practical manual; edited by V.V. Sukhorukov. - M .: Higher school, 1992. - 312 pp., Ill.). The sensitivity zone of the inductor (i.e., the space in which its magnetic field exists) is an egg-shaped body of revolution, the axial section of half of which is shown in FIG. 2. The size of the control zone Z _to , ie the distance from the coil to the surface of the test object depends on the radius of the coil Z _to ≈ 4 ÷ 5R. The device is equipped with several measuring coils of different radii, the signals of which depend on the presence and position of metal particles and are fed to the indicator unit through processing circuits.

Experimental studies were carried out on PCM samples (Fig. 3) with artificial metal inclusions of different sizes (Fig. 4) located at different depths relative to the control surface. A photograph of the experimental setup is shown in FIG. 5.

As the results of the experiment in FIG. Figure 6 shows the dependence of the readings on the dimensions of the metal inclusion in the PCM.

From FIG. Figure 6 shows that the proposed device can detect small inclusions up to 2 mm in size, which is several times smaller than the device adopted as a prototype.

)), k - коэффициент пропорциональности, определяемый по формуле

где N - количество измерительных катушек) исходя из предполагаемой глубины залегания и размеров металлических включений.Fig. 7 shows the results of various experiments to determine the location and size of metal inclusions in the PCM, modeled in the ANSYS Maxwell software environment. The dependences of the error Δ = kZ (where Z is the maximum scanning depth (

)), k is the proportionality coefficient determined by the formula

where N is the number of measuring coils) based on the estimated depth and size of metal inclusions.

To confirm the operability of the proposed device and its destination indicators from the point of view of reducing the error in determining the coordinates of detected inclusions, experimental studies were conducted on real material.

As the object of study, we used a polymer composite material (a plate 30 mm thick) in which four metal inclusions were located at a predetermined depth - metal balls (steel 20) with a diameter of 0.5 mm at different distances from the measurement surface: 3 mm, 12 mm, 20 mm, 27 mm.

In FIG. 8 shows the experimental design.

Fig. 9 is a photograph of an experiment process.

In accordance with the formula of the proposed application for the invention, the radius of the exciting coil is determined based on the parameters of the controlled material according to the formula:

In accordance with the application formula defined:

- frequency of the harmonic oscillator according to the formula

- the number of measuring inductors based on the estimated depth and size of metal inclusions and the error in determining the location of small metal inclusions: N = 4,

- the radii of the measuring inductance coils:

R _11.2 = 12 mm is the radius of the first measuring inductor of the induction transducer;

R _11.3 = 9.5 mm is the radius of the second measuring inductor of the induction transducer;

R _11.4 = 7 mm is the radius of the third measuring inductor of the induction transducer;

R _11.5 = 3.5 mm is the radius of the fourth measuring inductor of the induction converter.

Based on the results obtained, an induction converter is manufactured.

Experimental studies were carried out in accordance with FIG. 8 and FIG. 9.

The purpose of the experimental research is to determine the error in measuring the depth of metal inclusions of the claimed device and the device adopted as a prototype.

The results of experimental studies are shown in FIG. 10.

From the results of the experiment it can be seen that the error in determining the occurrence depth of small-sized metal inclusions by the claimed device was no more than 10% and unchanged for all inclusions (metal balls). Using the device adopted as a prototype, the error in determining the depth is approximately 1.5-2 2 times more and amounts to 20% ..

The invention has the following advantages:

- detect small metal inclusions with sizes from 0.1 to 2 mm in PCM products with a detection error of less than 10%;

- improves the quality of PCM structures due to the timely and reliable detection of the location of metal inclusions, which allows for their timely repair.

Claims (19)

1. A device for determining the position of small metal inclusions in products made of composite materials, including: first - fourth amplifiers (1, 4, 5, 9); first - second synchronous detectors (2, 3); two-channel analog-to-digital converter (6); processing unit (7); indicator (8) and induction converter (11); moreover the input of the first amplifier (1) is connected to the induction converter (11), and its output is connected to the first inputs of the first and second synchronous detectors (2, 3); the output of the first synchronous detector (2) is connected to the input of the second amplifier (4); the output of the second synchronous detector (3) is connected to the input of the third amplifier (5); the outputs of the second and third amplifiers (4, 5) are connected to the inputs of a two-channel analog-to-digital converter (6); and its output - with the input of the processing unit (7); the first output of the processing unit (7) is connected to the second inputs of the first and second synchronous detectors (2, 3), its second output is connected to the input of the fourth amplifier (9), and its third output is connected to the indicator input (8); the output of the fourth amplifier (9) is connected to the input of the induction converter (11); characterized in that a switch (10) connected between the induction converter and the first amplifier is introduced into it, while induction converter (11) includes exciting inductor (11.1), the radius of which R _in selected taking into account the maximum thickness of the product from a composite material from the condition

where T _ok - the maximum thickness of the investigated object, and measuring inductors, the outputs of which are connected to the corresponding inputs of the switch (10) and which are concentrically located inside the exciting inductor (11.1); the number of measuring coils of the induction converter and their radii are determined based on the assumed depth and size of the metal inclusions and the necessary error in determining the location of small-sized metal inclusions, and the input of the induction converter (11) is the input of the exciting inductor (11.1). 2. The device according to p. 1, characterized in that: processing unit (7) includes a microprocessor and a harmonic oscillation generator associated with its output, while the frequency ω of the harmonic oscillator is selected from the condition

Where

- the minimum possible value of electrical conductivity of small-sized metal inclusions in a controlled composite material, and μ ₀ is the magnetic constant of vacuum.

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