A device and method for testing the sensitivity consistency of an acoustic emission sensor

Abstract

A test device and method for the sensitivity consistency of an acoustic emission sensor, wherein the device uses a cylindrical organic glass rod as a test bench; a clamping seat, a clamping block and a mounting tube are installed at one end of the test bench, and under the action of a compression spring, the end face of the sensor under test maintains a pressure-stable coupling contact with the end face of the test bench; a bracket is installed on the other end face of the test bench, and together with a fixing seat and a clamping seat, the test bench is kept horizontally placed on a desktop. By adjusting the width and amplitude of the pulse excitation signal of the signal generator, and according to the sensitivity distribution and aggregation between each sensor under test, a consistency calculation method is used to screen out sensors under test with first, second and third sensitivity consistency. The test device is low in cost, easy to carry and easy to set up, and the test method is simple and quick, easy for users to operate, and the sensitivity consistency test of the sensor can be performed at any time according to the detection requirements.

Description

Technical Field

[0001] The present invention relates to the field of acoustic emission technology, and in particular to a device and method for testing the sensitivity consistency of an acoustic emission sensor. Background Art

[0002] Acoustic emission testing is often used for integrity testing and safety evaluation of large structures, such as large pressure vessels, storage tanks, lifting machinery, building steel structures, etc. According to the actual test object, it is necessary to install several to dozens of acoustic emission sensors for detection and positioning. The good consistency of acoustic emission sensor sensitivity is the premise for effective and reliable test results, which is the guarantee of accurate positioning and evaluation of the sound source in the test object.

[0003] The pre-delivery inspection of acoustic emission sensors can ensure high sensitivity, compliance with inspection standards, and qualified quality. However, after being put into use, the sensor sensitivity is prone to decrease due to harsh on-site environment, wear and tear, improper operation, etc. At present, the calibration of acoustic emission related equipment only requires metrological calibration of acoustic emission sensors once a year, and the calibration is based on GB / T 19800 "First-level calibration of acoustic emission transducers for non-destructive testing" and GB / T 19801 "Second-level calibration of acoustic emission sensors for non-destructive testing". The calibration of acoustic emission sensors in GB / T19800 and GB / T 19801 has the following problems:

[0004] 1. The excitation source is a step function force source, which must be generated by breaking a glass capillary. The specific method is to use a glass capillary with a diameter of about 0.2 mm and place it horizontally on the test block. The force is loaded on the capillary through a solid glass rod. The glass rod applies force downward through a loading screw until the capillary glass tube breaks. This excitation method is complex, difficult to operate, and the excitation effect is unstable.

[0005] 2. The test block used is a steel cylindrical test block. In order to reduce the influence of boundary effect, the diameter of the cylindrical test block is not less than 400mm and the height is not less than 180mm. The test block is large and very heavy.

[0006] 3. The first-level calibration uses a standard capacitive sensor as the reference sensor, and the second-level calibration uses an NBS conical transducer, which is no longer available on the market.

[0007] 4. Use a transient recorder or oscilloscope to record the data, and then use a computer to perform complex calculations on the recorded data to obtain the results.

[0008] 5. Calibration is a test of each sensor and cannot give a direct result of the difference between a group of sensors, that is, it does not give a suitable result for field testing of the consistency of a sensor group.

[0009] 6. Annual calibration can only ensure that the sensitivity of a single sensor meets the minimum detection requirements during and before the test. It is impossible to know the situation after calibration and after wear and tear. Due to the lack of consistency testing of the sensitivity of the acoustic emission sensor before actual testing, large differences in detection sensitivity often occur during acoustic emission testing, resulting in inaccurate positioning and quantitative test results.

[0010] In summary, existing acoustic emission sensor testing methods require the use of complex electronic instruments and bulky large steel test blocks. The entire device is complex, costly, and the test calculations are complex. General users do not have the conditions and capabilities to perform the tests. In particular, when using the breakage of a capillary glass tube as an excitation source, a standard capacitive sensor is also required as a reference object in the first-level calibration. General users do not have the conditions and capabilities to perform sensor calibration. If all sensors are sent to the Metrology Institute for calibration before each test, the cost is high and the efficiency is low. Therefore, there is an urgent need for a convenient and effective method for testing the sensitivity consistency of acoustic emission sensors to ensure that users can test and evaluate the consistency of acoustic emission sensors before each test or during routine instrument maintenance, thereby ensuring the validity and reliability of the test data and improving the test efficiency. Summary of the invention

[0011] The purpose of the present invention is to propose a testing method and device to solve the problems of the prior art, such as untimely and inconvenient calibration and inability to provide consistency information.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] A device for testing the sensitivity consistency of an acoustic emission sensor comprises: a signal generator 2, an emission sensor 3, a first signal line 5, a preamplifier 6, a second signal line 7, an acoustic emission instrument 8, a computer device 9 and a third signal line 10; a sensor 4 to be tested is sequentially connected to the second signal line 7, the preamplifier 6 and the first signal line 5 and transmits the signal to be tested to the acoustic emission instrument 8 and the computer device 9, and the computer device 9 calculates and displays the amplitude of the collected acoustic emission signal.

[0014] A cylindrical organic glass rod with a length of 1000 mm and a diameter of 50 mm is used as the test bench 1, and the end of the test bench 1 closer to the sensor 4 under test is the proximal end surface, and the opposite end is the distal end surface;

[0015] The transmitting sensor 3 is placed in a fixing seat 11 at 300 mm from the proximal end surface of the test bench 1, fixed with a cover plate 12 to maintain stable coupling contact with the surface of the test bench, and connected to the signal generator 2 through a third signal line 10; the clamping seat 13 is installed on the proximal end surface of the test bench 1 with a clamping block 16; the sensor 4 to be measured is placed in a mounting tube 14, which has an annular ear piece on its body and a compression spring 15 installed inside. The annular ear piece and the mounting tube 14 are inserted into the corresponding slot of the clamping seat 13 by pressing. Under the action of the compression spring 15, the end face of the sensor 4 to be measured maintains a pressure-stable coupling contact with the end face of the test bench; the bracket 17 is installed on the distal end surface of the test bench 1, and together with the fixing seat 11 and the clamping seat 13, keeps the test bench horizontally placed on the desktop.

[0016] The acoustic emission sensor sensitivity consistency test method based on the above device includes the following steps:

[0017] Step 1, signal excitation and reception; adjust the pulse excitation signal width and amplitude of the signal generator 2 so that the amplitude of the acoustic emission signal received by the above-mentioned sensor 4 under test reaches 80% of the full-scale value of the amplitude; under the condition that the pulse signal remains unchanged, test the response amplitude of the acoustic emission signal received by other sensors 4 under test at the same position one by one;

[0018] Step 2, test the sensitivity consistency deviation ΔAi; the total number of sensors 4 under test is n, the amplitude value obtained by the i-th sensor 4 under test is A(i), in dB; the average amplitude of all sensors 4 under test is Set the sensitivity consistency deviation threshold to X dB and observe the amplitude values ​​of all the sensors under test. The sensitivity value of the sensor 4 under test with a value of ±X dB is recorded as A(i) l(j) , let the number of the tested sensors 4 of this type be m, then the sensitivity consistency deviation ΔAi of each tested sensor 4 within the threshold range is:

[0019]

[0020] The sensitivity consistency deviation ΔAix calculated by the sensitivity consistency deviation threshold is:

[0021] Step 3, consistency comparison of multiple sensors 4 under test; determine the first preset deviation range and the second preset deviation range according to the model of the sensor under test and the detection requirements, and any value within the first preset deviation range is smaller than any value in the second preset deviation range, and any value in the second preset deviation range is smaller than the sensitivity consistency deviation ΔAix calculated by the sensitivity consistency deviation threshold; when ΔAi belongs to the first preset deviation range, the first sensitivity consistency is satisfied; when ΔAi belongs to the second preset deviation range, the second sensitivity consistency is satisfied; when ΔAi exceeds the second preset deviation range, the third sensitivity consistency is satisfied; according to the ΔAi obtained from each sensor 4 under test, determine that its sensitivity consistency range belongs to the first sensitivity consistency, the second sensitivity consistency, or the third sensitivity consistency; according to the actual detection requirements for the number of sensors, multiple sensors 4 under test within the first sensitivity consistency range are preferably used for acoustic emission detection; when the number of sensors 4 under test within the first sensitivity consistency range is insufficient to meet the detection requirements, multiple sensors 4 under test within the second sensitivity consistency range are selected, and so on.

[0022] Furthermore, the transmitting sensor is a wide-band sensor whose frequency band range can cover the frequency band range of the sensor to be measured, or a sensor of the same model as the sensor to be measured is used as the transmitting sensor.

[0023] Furthermore, the excitation signal modulated by the signal generator is selected to be a single pulse signal excitation, and the selection of the pulse signal width should match the frequency band characteristics of the sensor to be measured.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The sensitivity consistency test of acoustic emission sensors is to test the relative consistency of a batch of sensors. All the sensors under test can be directly tested for evaluation without using reference sensors.

[0026] 2. The test directly uses the acoustic emission instrument system to obtain the amplitude of the sensor's receiving signal, without the need to use other equipment and perform complex calculations, which simplifies the test device. The test method is simple and fast, and the user is easy to operate. The sensitivity consistency test of the sensor can be performed at any time according to needs.

[0027] 3. The calculation of the sensitivity consistency of the acoustic emission sensor is based on the sensor with the highest sensitivity as a reference, and then the sensor within the preset deviation range of the sensitivity consistency is selected. In this way, under the premise of ensuring that the sensor has high sensitivity, a group of sensors with good sensitivity consistency are selected for acoustic emission detection, which provides a more reliable guarantee for the accuracy of on-site acoustic emission detection results.

[0028] 4. The test device has good reproducibility, and the test is convenient, efficient and portable. (1) The generator modulates the pulse signal to excite the transmitting sensor. The equipment is simple and easy to operate, not subject to human interference, and the excitation signal parameters can be adjusted according to the test sensor. (2) The cylindrical plexiglass rod with a length of 1000mm and a diameter of 50mm is low-cost, light, easy to store and use as a test bench. (3) The use of a cylindrical plexiglass rod as a test bench effectively avoids the interference of the end face echo on the side of the cylinder where the sensor is not installed on the amplitude of the acoustic emission signal received by the sensor under test.

[0029] 5. The cylindrical organic glass rod is fixed by the clamp seat, fixed seat and bracket to prevent it from rolling on the table, thus ensuring the stability of the test bench. The sensor to be tested is placed in the clamp seat by the installation tube, and a fixed pressure is applied to the sensor and the end face of the test bench by the compression spring, which not only facilitates the replacement of the sensors to be tested, but also ensures the consistency of the coupling position and pressure of each sensor to be tested and the test bench.

[0030] The acoustic emission sensor sensitivity consistency test method described in the present invention is convenient, efficient, low-cost, and easy for users to operate. It can timely discover acoustic emission sensors with insufficient sensitivity consistency in a group of sensors used for acoustic emission positioning detection before the implementation of acoustic emission detection or during daily equipment maintenance, and replace them in time, thereby improving the efficiency of acoustic emission on-site detection and ensuring the reliability of acoustic emission detection results. The acoustic emission sensor sensitivity consistency test method and device provided by the present invention uses a signal generator to generate an excitation signal at the center of a plexiglass rod test bench, adopts a method of controlling a single variable, measures the sensitivity consistency deviation between acoustic emission sensors of the same model, compares it with a preset consistency deviation range, and performs an acoustic emission sensor sensitivity consistency test. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a testing device of the present invention is shown;

[0032] Figure 2 Different angle views of the installation of the clamping seat, the mounting cylinder, the compression spring, the clamping block, the fixing seat, the cover plate and the bracket on the test bench are shown;

[0033] Figure 3 The figure shows the waveform of the acoustic emission signal received by a certain sensor under test.

[0034] Among them, the correspondence between the components and the figure marks is: test bench 1, signal generator 2, emission sensor 3, multiple sensors under test 4, first signal line 5, preamplifier 6, second signal line 7, acoustic emission instrument 8, computer equipment 9, third signal line 10, fixing seat 11, cover plate 12, clamping seat 13, mounting tube 14, compression spring 15, clamping block 16 and bracket 17. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] A method for testing the sensitivity consistency of an acoustic emission sensor is provided. Taking two groups of 18 acoustic emission sensors of the same model (the first group of acoustic emission sensors has a frequency band range of 100kHz to 450kHz and a center frequency of 150kHz; the second group of acoustic emission sensors has a frequency band range of 100kHz to 850kHz and a center frequency of 350kHz) as examples, sensitivity consistency testing and evaluation are performed respectively.

[0037] Step 1: Build the test device. Figure 1 ; It includes: a cylindrical organic glass rod with a length of 1000 mm and a diameter of 50 mm as a test bench 1, a signal generator 2, an emission sensor 3 with a frequency band range of 100kHz to 900kHz, a plurality of sensors 4 under test, two groups of 18 each, a first signal line 5, a preamplifier 6, a second signal line 7, an acoustic emission instrument 8, a computer device 9 and a third signal line 10;

[0038] A clamp seat 13 is installed at one end of the test bench 1, and the clamp seat 13 is fixed to the end face of the test bench with a clamping block 16. This end face is the proximal end face of the test bench 1, and the opposite end face is the distal end face; a sensor 4 under test of the first group is placed in the installation tube 14, and its wiring port is provided with an avoidance groove at the corresponding position of the installation tube. A compression spring 15 is installed inside the installation tube 14, and an annular ear piece is provided on the body of the installation tube. The sensor 4 under test is pressed by hand to insert it together with the installation tube 14 into the corresponding slot of the clamp seat 13. Under the action of the compression spring 15, the end face of the sensor 4 under test maintains a pressure-stable coupling contact with the end face of the test bench; the transmitting sensor 4 is placed in the installation tube 14, and the sensor 4 under test is placed in the installation tube 14. The sensor 3 is placed in a fixing seat 11 at a distance of 300 mm from the proximal end surface of the test bench 1, and is fixed with the surface of the test bench by a cover plate 12 to maintain stable coupling contact; the signal generator 2 and the emission sensor 3 are connected by a third signal line 10; the bracket 17 is installed on the distal end surface of the test bench 1, and together with the fixing seat 11 and the clamping seat 13, the test bench is kept horizontally placed on the desktop; the sensor 4 to be tested is connected to the second signal line 7, the preamplifier 6, and the first signal line 5 in sequence, and the measured signal is transmitted to the acoustic emission instrument 8 and the computer device 9, and the computer device 9 calculates and displays the amplitude of the collected acoustic emission signal;

[0039] Step 2, signal excitation and reception: Use a signal generator to modulate a single pulse signal to excite the transmitting sensor, and adjust the pulse width and pulse voltage so that the amplitude of the acoustic emission signal received by the first sensor under test is 80dB, recorded as A(1). The above completes the initial test conditions, and the sensitivity consistency deviation threshold is set to 6dB.

[0040] Under the initial test conditions, the pulse signal modulated by the signal generator, the transmitting sensor, the acoustic emission instrument channel, the signal line, the preamplifier, and the signal cable remained unchanged. The other 17 sensors under test in the first group were replaced and tested in turn. The response amplitudes A(2) to A(18) received by each sensor were recorded, as shown in Table 1.

[0041] Table 1 Sensitivity test results of the first group of acoustic emission sensors

[0042] Sensor test value A(1) A(2) A(3) A(4) A(5) A(6) Amplitude(dB) 80.0 81.5 80.2 78.1 80.8 79.6 Sensor test value A(7) A(8) A(9) A(10) A(11) A(12) Amplitude(dB) 82.2 79.8 68.3 80.4 76.5 78.6 Sensor test value A(13) A(14) A(15) A(16) A(17) A(18) Amplitude(dB) 81.2 77.8 80.3 72.1 78.4 80.6

[0043] Step 3, test the sensitivity consistency deviation ΔAi; first, calculate the amplitude mean of the first group of 18 tested sensors Observe the amplitude values ​​of all the sensors under test, exceeding The sensors with a value of ±6dB are A(9) and A(16), so the sensitivity consistency of these two sensors is low, recorded as A(9) l(1) and A(16) l(2) For the test results of 16 acoustic emission sensors within the threshold range, according to the above acoustic emission sensor sensitivity consistency evaluation method, the sensitivity consistency deviation of each acoustic emission sensor is calculated, see Table 2:

[0044] The sensitivity consistency deviation ΔAix calculated by the sensitivity consistency deviation threshold is:

[0045] Table 2 Sensitivity consistency deviation of the first group of acoustic emission sensors

[0046] Sensor consistency deviation <![CDATA[ΔA1]]> <![CDATA[ΔA2]]> <![CDATA[ΔA3]]> <![CDATA[ΔA4]]> <![CDATA[ΔA5]]> <![CDATA[ΔA6]]> Deviation value 0.3％ 2.2％ 0.6％ 2.1％ 1.3％ 0.2％ Sensor consistency deviation <![CDATA[Δ7]]> <![CDATA[ΔA8]]> <![CDATA[ΔA9]]> <![CDATA[ΔA 10 ]]> <![CDATA[ΔA 11 ]]> <![CDATA[ΔA 12 ]]> Deviation value 3.0％ 0.1％ - 0.8％ 4.1％ 1.4％ Sensor consistency deviation <![CDATA[ΔA 13 ]]> <![CDATA[ΔA 14 ]]> <![CDATA[ΔA 15 ]]> <![CDATA[ΔA 16 ]]> <![CDATA[ΔA 17 ]]> <![CDATA[ΔA 18 ]]> Deviation value 1.8％ 2.4％ 0.7％ - 1.7％ 1.1％

[0047] Step 4, consistency comparison of multiple tested sensors; for the consistency of the acoustic emission sensor, according to the sensor type and the actual detection requirements, the first preset deviation range is set to (0, 2.0%] and the second preset deviation range is set to (2.0%, 3.7%]. Therefore, for the first group of 18 acoustic emission sensors tested, their sensitivity deviations are determined according to the consistency deviation method to obtain the sensitivity consistency results of each sensor. The sensor sensitivity consistency belongs to the first preset deviation range, that is, the first sensitivity consistency is recorded as A, the sensor sensitivity consistency belongs to the second preset deviation range, that is, the second sensitivity consistency is recorded as B, and the sensor sensitivity consistency that exceeds the second preset deviation range is recorded as C, see Table 3.

[0048] Table 3 Consistency results of the first group of acoustic emission sensors

[0049] Sensor No. 1 2 3 4 5 6 Sensitivity consistency A B A B A A Sensor No. 7 8 9 10 11 12 Sensitivity consistency B A Low A C A Sensor No. 13 14 15 16 17 18 Sensitivity consistency A B A Low A A

[0050] In summary, according to the above analysis results of the first group of acoustic emission sensor sensitivity consistency test, it is recommended to use 11 acoustic emission sensors with the first sensitivity consistency to perform cylindrical positioning on cylindrical containers for the actual detection object; if the number of sensors is insufficient, add 4 acoustic emission sensors with the second sensitivity consistency to participate in positioning. This acoustic emission sensor selection scheme not only meets the acoustic emission detection needs, but also makes full use of the advantages of the acoustic emission sensor sensitivity consistency to obtain more accurate detection results.

[0051] Similarly, the sensitivity consistency test and evaluation of the second group of 18 acoustic emission sensors were carried out using the above steps, and the sensitivity consistency deviation threshold was set to 6dB. Since the test steps are the same as the first group, they will not be repeated here, and only the test and analysis results are shown as follows:

[0052] The response amplitudes received by the second group of 18 tested sensors are shown in Table 4.

[0053] Table 4 The second group of acoustic emission sensor sensitivity test results

[0054]

[0055] Calculate the amplitude mean of the second group of 18 measured sensors Observe the amplitude values ​​of all the sensors under test, exceeding The sensors with a value of ±6dB are A(9), A(13) and A(14). The sensitivity consistency of these three sensors is low, recorded as A(9). l(1) and A(13) l(2) and A(14) l(3) Based on the test results of 15 acoustic emission sensors within the threshold range, the sensitivity consistency deviation of each acoustic emission sensor is calculated, as shown in Table 5:

[0056]

[0057] The sensitivity consistency deviation ΔAix calculated by the sensitivity consistency deviation threshold is:

[0058] Table 5 The second group of acoustic emission sensor sensitivity consistency deviation

[0059] Sensor consistency deviation <![CDATA[ΔA1]]> <![CDATA[ΔA2]]> <![CDATA[ΔA3]]> <![CDATA[ΔA4]]> <![CDATA[ΔA5]]> <![CDATA[ΔA6]]> Deviation value 0.5％ 1.1％ 1.2％ 2.6％ 2.7％ 0.1％ Sensor-Consistency Deviation <![CDATA[ΔA7]]> <![CDATA[ΔA8]]> <![CDATA[ΔA9]]> <![CDATA[ΔA 10 ]]> <![CDATA[ΔA 11 ]]> <![CDATA[ΔA 12 ]]> Deviation value 1.6％ 0.8％ - 3.7％ 1.9％ 2.1％ Sensor consistency deviation <![CDATA[ΔA 13 ]]> <![CDATA[ΔA 14 ]]> <![CDATA[ΔA 15 ]]> <![CDATA[ΔA 16 ]]> <![CDATA[ΔA 17 ]]> <![CDATA[ΔA 18 ]]> Deviation value - - 0.01％ 3.1％ 1.3％ 0.01％

[0060] According to the sensor type and actual detection requirements, the first preset deviation range is set to [0, 2.0%] and the second preset deviation range is set to [2.0%, 3.5%]. Therefore, for the second group of 18 acoustic emission sensors tested, their sensitivity deviations are determined according to the consistency deviation method, and the sensitivity consistency results are shown in Table 6.

[0061] Table 6 Consistency results of the second group of acoustic emission sensors

[0062] Sensor No. 1 2 3 4 5 6 Sensitivity consistency A A A B B A Sensor No. 7 8 9 10 11 12 Sensitivity consistency A A Low C A B Sensor No. 13 14 15 16 17 18 Sensitivity consistency Low Low A B A A

[0063] In summary, according to the above-mentioned second group of acoustic emission sensor sensitivity consistency test analysis results, for the actual detection object of steel structure acoustic emission detection, it is recommended to give priority to the use of 10 acoustic emission sensors with the first sensitivity consistency for positioning; if the number of sensors is insufficient, add 4 acoustic emission sensors with the second sensitivity consistency to participate in positioning. With this acoustic emission sensor selection scheme, although the 9th and 14th acoustic emission sensors with the highest sensitivity are not selected, a group of sensors with high sensitivity consistency are selected for detection, which provides a higher guarantee for the accuracy of the positioning results.

[0064] It is particularly noted that the method described in the present invention is applicable to engineering inspection applications that use multiple sensors to detect acoustic emission signals and are arranged in an array to locate acoustic emission sources. In practice, multiple purchased probes need to be calibrated before on-site inspection. However, for multiple probes in different situations such as worn probes and newly purchased probes, the positioning effect may not be optimal when used together. The reason is that positioning requires the coordination of an array of multiple probes. When the sensitivity of only one or a few probes is much higher than the requirements of the inspection site, the positioning accuracy of the combined array with the other majority of probes is not high. This is closely related to the amplitude threshold positioning principle of the probe. Therefore, the present invention proposes a consistency test method to ensure that the sensitivity of the array probe meets the test requirements, and to minimize the difference between the sensitivities of multiple different sensors used in the inspection, thereby improving the positioning accuracy by about 20%-40%. This breaks the common technical inertia of thinking that the higher the sensor sensitivity, the more accurate the positioning. For example, when a probe with a sensitivity of 98dB is positioned with a group of probe arrays of about 87dB-90dB, due to the noise on site, the noise threshold of the 98dB probe often needs to be 6dB higher than that of other probe sensors, and the advantage of high sensitivity is not actually brought into play. At the same time, the setting of the noise threshold requires empirical adjustment and estimation, which is not conducive to the precision control and reproducibility of the test results. After the present invention adopts consistency testing, it ensures that the sensitivity of the probes used at the test site is clustered and consistent, the noise threshold is set consistently, the positioning accuracy is greatly improved, and the accuracy and effectiveness of the test results are effectively ensured.

[0065] Special instructions on sensitivity consistency and sensitivity calibration described in the present invention are as follows:

[0066] 1. The two have different concepts and meanings. Sensitivity reflects the response value of the sensor to the signal received. Generally, the higher the better. The detection standard sets a minimum sensitivity requirement for a single sensor. However, sensitivity consistency reflects the regularity and uniformity of the response value of a group of sensors to the same sound source. The smaller the difference between the upper and lower amplitudes, the better. The present invention sets a maximum value requirement for the consistency difference.

[0067] 2. The two are used for different purposes. Calibration measures the spectrum curve of a single sensor, and the purpose is to obtain the sensor's response amplitude at different frequencies, that is, to test the absolute value of the sensor's sensitivity based on theoretical calculations, and provide a basis for selecting sensor types for different detection purposes; sensitivity consistency testing is based on actual engineering needs, under the guidance of theoretical calculations, to determine reasonable and fixed test conditions, and test the response amplitude of a group of sensors, in order to obtain the relative difference in sensor sensitivity consistency, and provide a basis for a group of sensors with good consistency for detection implementation.

[0068] 3. The actual application requirements of the test are different. The sensitivity test is conducted before the on-site acoustic emission detection is implemented. It can effectively remove the response difference factors of the sensor in the sensitivity verification of the on-site acoustic emission system, timely discover the faults such as the system channel connection, and improve the detection efficiency. The sensitivity consistency test is a combination of actual engineering needs and theoretical calculations. It focuses on testing the sensitivity-related uniformity of a group of sensors, which is conducive to simplifying the test equipment and test methods, and improving the positioning accuracy of the positioning group and the accuracy of the amplitude test.

[0069] 4. According to the sound velocity of organic glass and the acoustic path difference of sound wave propagation in the test bench, the echo of the far end surface of the test bench arrives some time after the sensor under test receives the transmission signal, which has no effect on the amplitude test of the received signal. Figure 3 .

[0070] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An acoustic emission sensor sensitivity consistency test device, comprising: A signal generator (2), an emission sensor (3), a first signal line (5), a preamplifier (6), a second signal line (7), an acoustic emission instrument (8), a computer device (9) and a third signal line (10); the sensor (4) to be tested is connected to the second signal line (7), the preamplifier (6) and the first signal line (5) in sequence and transmits the signal to be tested to the acoustic emission instrument (8) and the computer device (9), and the amplitude of the collected acoustic emission signal is calculated and displayed by the computer device (9), characterized in that: a cylindrical organic glass rod with a length of 1000 mm and a diameter of 50 mm is used as a test bench (1), and the end of the test bench (1) closer to the sensor (4) to be tested is a proximal end surface, and the opposite end is a distal end surface; The transmitting sensor (3) is placed in a fixing seat (11) at 300 mm from the proximal end surface of the test bench (1), fixed with the surface of the test bench by a cover plate (12) to maintain stable coupling contact, and connected to the signal generator (2) by a third signal line (10); the clamping seat (13) is installed on the proximal end surface of the test bench (1) by a clamping block (16); the sensor to be tested (4) is placed in a mounting tube (14), the mounting tube body is provided with a circular ear piece, and a compression spring (15) is installed inside, and the circular ear piece and the mounting tube (14) are pressed to be inserted into the corresponding slot of the clamping seat (13), and under the action of the compression spring (15), the end face of the sensor to be tested (4) maintains pressure-stable coupling contact with the end face of the test bench; the bracket (17) is installed on the distal end surface of the test bench (1), and together with the fixing seat (11) and the clamping seat (13), keeps the test bench horizontally placed on the desktop.

2. The testing method of the acoustic emission sensor sensitivity consistency testing device according to claim 1, comprising the following steps: Step 1, signal excitation and reception; adjusting the width and amplitude of the pulse excitation signal of the signal generator (2) so that the amplitude of the acoustic emission signal received by the above-mentioned sensor (4) under test reaches 80% of the full-scale value of the amplitude; under the condition that the pulse signal remains unchanged, testing the response amplitude of the acoustic emission signal received by other sensors (4) under test at the same position one by one; Step 2, test the sensitivity consistency deviation ΔAi; the total number of the tested sensors (4) is n, the amplitude value obtained by the i-th tested sensor (4) is A(i), in dB; the average amplitude of all the tested sensors (4) is Assume that the sensitivity consistency deviation threshold is X dB, and observe the amplitude values ​​of all the sensors under test. The sensitivity value of the sensor (4) under test with a value of ±X dB is denoted by A(i) 1(j) , let the number of the tested sensors (4) of this type be m, then the sensitivity consistency deviation ΔAi of each tested sensor (4) within the threshold range is: The sensitivity consistency deviation ΔAix calculated by the sensitivity consistency deviation threshold is: Step 3, comparing the consistency of multiple sensors (4) under test; determining a first preset deviation range and a second preset deviation range according to the model of the sensor under test and the detection requirements, and any value within the first preset deviation range is smaller than any value within the second preset deviation range, and any value within the second preset deviation range is smaller than a sensitivity consistency deviation ΔAix calculated by a sensitivity consistency deviation threshold; when ΔAi belongs to the first preset deviation range, the first sensitivity consistency is satisfied; when ΔAi belongs to the second preset deviation range, the second sensitivity consistency is satisfied; when ΔAi exceeds the second preset deviation range, the third sensitivity consistency is satisfied; according to the ΔAi obtained for each sensor under test (4), determining that the range to which its sensitivity consistency belongs is the first sensitivity consistency. The method comprises the following steps: first, a first sensitivity consistency, a second sensitivity consistency, or a third sensitivity consistency; based on the actual detection requirement for the number of sensors, a plurality of sensors (4) to be tested within the first sensitivity consistency range are preferentially selected for acoustic emission detection; when the number of sensors (4) to be tested within the first sensitivity consistency range is insufficient to meet the detection requirement, a plurality of sensors (4) to be tested within the second sensitivity consistency range are selected, and so on; when the plurality of sensors (4) to be tested selected after the consistency detection are used for acoustic emission positioning detection and monitoring, the consistency of the sensitivity response makes the setting of various detection parameters of each sensor simple and consistent, thereby enhancing the debugging convenience of the positioning test and improving the positioning accuracy, and ensuring the accuracy and effectiveness of the detection results.

3. The testing method of the acoustic emission sensor sensitivity consistency testing device according to claim 2, characterized in that: The transmitting sensor should be a wide-band sensor whose frequency band can cover the frequency band of the sensor to be tested, or a sensor of the same model as the sensor to be tested can be used as the transmitting sensor.

4. According to the test method for the sensitivity consistency of the acoustic emission sensor described in claim 2, the excitation signal modulated by the signal generator is selected to be a single pulse signal excitation, and the selection of the pulse signal width should match the frequency band characteristics of the sensor being tested.

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