Device and method for measuring corrosion characteristic parameters of grouting sleeve connecting piece

Abstract

The invention discloses a device and method for measuring corrosion characteristic parameters of a grouting sleeve connecting piece, and belongs to the field of assembly structures, the device mainly comprises a CCD camera and a telescopic probe device, a rigid probe of the telescopic probe device is in contact with the surface of the grouting sleeve connecting piece to be measured, the CCD camera is connected with a computer, and the computer is connected with the CCD camera. The relative positions of the CCD camera and the telescopic probe device are not changed in the moving process, at the beginning, a rigid probe of the telescopic probe device makes contact with the starting point of the measuring area range, when the rigid probe of the telescopic probe device moves to the end point of the measuring area range, measurement is stopped, and in the whole measuring process, the CCD continuously shoots videos and automatically stores the videos in the computer. The method is used for measuring the corrosion characteristic parameters of the grouting sleeve connecting piece based on the device. According to the method, comprehensive and accurate measurement of the size and depth of the rust pit can be realized, and the method has an application value for mechanical property degradation evaluation of a large-scale and wide-range service assembly type structure after corrosion.

Description

Technical Field

[0001] The invention relates to the field of assembled structures, and in particular to a device and method for measuring corrosion characteristic parameters of a grouting sleeve connector. Background Art

[0002] Prefabricated structures have been widely used in buildings and bridges due to their advantages such as fast construction speed and easy quality control. Prefabricated structures are mainly made of reinforced concrete and face the unavoidable risk of corrosion during their service life. Grouting sleeve connectors are key force-transmitting components of prefabricated structures. The degradation of their mechanical properties after corrosion will directly threaten the safety of the structure in service.

[0003] The degradation of mechanical properties of grouting sleeve connectors is directly related to the characteristic parameters of sleeve surface corrosion. Existing studies mostly use visual inspection and weighing methods to obtain the average corrosion degree of sleeves in grouting sleeve connectors, which is difficult to reflect the degradation mechanism of the force transmission performance of grouting sleeve connectors caused by the uncertainty of corrosion, and underestimates the potential harm of corrosion to the mechanical properties of assembled structures. The existing precision detection methods mainly include scanning and ultrasonic detection methods, which have high testing costs, may not be sensitive enough to certain types of corrosion (uniform corrosion), and cannot detect large-volume grouting sleeve connectors due to experimental conditions. Summary of the invention

[0004] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a device and method for measuring the characteristic parameters of corrosion of a grouting sleeve connector, thereby realizing automatic and accurate measurement of the size, depth and position of rust pits on the sleeve surface of the grouting sleeve connector, and solving the defects of high cost and non-universality in the existing detection methods.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned purpose is:

[0006] According to a first aspect of the present invention, a device for measuring characteristic parameters of corrosion of a grouting sleeve connector comprises: a base, a first drive device, a second drive device, a slide rail, a moving device, a CCD camera and a retractable probe device, wherein the base is provided with a clamping device for clamping the grouting sleeve connector to be measured; the first drive device is used to drive the grouting sleeve connector to be measured to rotate around its own rotation axis; the CCD camera and the retractable probe device are fixed to a cantilever steel plate by bolts, and the relative positions of the CCD camera and the retractable probe device remain unchanged at all times, the CCD camera is connected to a computer, and the CCD camera is used to shoot a video of the entire process of the retractable probe device's telescopic deformation; the retractable probe device comprises a rigid probe, a probe housing and a spring , the spring is arranged inside the probe housing, and the top of the spring is against the top wall inside the probe housing; the central axis of the rigid probe and the central axis of the spring are in a straight line, the top of the rigid probe is fixedly connected to the spring, and the lower part of the rigid probe extends out of the probe housing. During measurement, the rigid probe contacts the surface of the grouting sleeve connector to be measured; the probe housing has a calibrated length, which is used to determine the conversion coefficient between the CCD camera pixel and the actual distance of the up and down movement of the rigid probe; the cantilever steel plate can move up and down in the vertical direction relative to the moving device, and can be fixed at a certain position of the moving device; the moving device is slidably matched with the slide rail, the moving device is connected to the second driving device, and moves along the slide rail under the drive of the second driving device; the slide rail is installed on the base.

[0007] According to a specific embodiment of the present invention, the clamping device includes a first support, a second support, a first clamping component and a second clamping component. The first support and the second support are installed on the base by bolts. The first clamping component is detachably installed on the first support, the second clamping component is detachably installed on the second support, and the first driving device is installed on the first support.

[0008] According to a specific embodiment of the present invention, the first clamping component and the second clamping component are spring clamps.

[0009] According to a specific embodiment of the present invention, the first driving device is a stepping motor.

[0010] According to a specific embodiment of the present invention, the moving device includes a steel clamp, a vertical slide rail, a connecting plate and a base plate. The steel clamp is fastened to the cantilever steel plate by bolts. The steel clamp is arranged on the vertical slide rail. The steel clamp can move along the length direction of the vertical slide rail and be locked at different positions. The vertical slide rail is fixed to the base plate by a connecting plate, and the connecting plate and the base plate are integrally formed. The connecting plate is connected to the output end of the second driving device. A slide groove matching the slide rail is arranged at the bottom of the base plate, and the second driving device is used to drive the moving device to move along the slide rail.

[0011] According to a specific embodiment of the present invention, the second driving device is a stepping motor.

[0012] According to a specific embodiment of the present invention, the rigid probe is a rigid probe with a ball needle.

[0013] According to a second aspect of the present invention, a method for measuring characteristic parameters of corrosion of a grouting sleeve connector is provided. The method is based on the device for measuring characteristic parameters of corrosion of a grouting sleeve connector according to claim 1, and specifically comprises:

[0014] Step 1: Soak, derust and dry the grouting sleeve connector to be tested in dilute hydrochloric acid with a mass concentration of 3.5%;

[0015] Step 2: Determine the starting point and end point of the measurement area on the surface of the grouting sleeve connector to be measured and mark them;

[0016] Step 3: Place the grouting sleeve connector to be tested on the device for measuring the characteristic parameters of rusting sleeve connectors, make the rigid probe contact the starting point of the measuring area, and adjust the lens of the CCD camera to clearly capture the entire rigid probe and the calibrated length value on the probe housing;

[0017] Step 4: According to the measurement accuracy requirements, adjust the parameters of the first driving device and the second driving device, determine the rotation speed of the grouting sleeve connector to be measured and the translation distance of the mobile device each time, and adjust the shooting frame rate of the CCD camera according to the measurement accuracy requirements;

[0018] Step 5: Control the first driving device to rotate the grouting sleeve connector to be tested 360 degrees at the rotation speed described in step 4. During the rotation of the grouting sleeve connector to be tested, the rigid probe contacts the surfaces of the grouting sleeve connector to be tested with different corrosion conditions, and continuously expands and contracts through the spring to reflect the size, depth and position of the rust pits on the sleeve surface of the grouting sleeve connector to be tested, and obtain the detection data of the grouting sleeve connector to be tested for one week, pause for 2 seconds, and then control the movement of the moving device through the second driving device, and drive the CCD camera, cantilever steel plate and retractable probe device to move. The single translation distance is determined by the accuracy required for measurement. After the movement is completed, pause for 2 seconds;

[0019] Step 6: Repeat step 5 continuously. When the rigid probe moves to the end point of the measuring area, the measurement is stopped. During the whole measuring process, the CCD camera continuously takes videos and automatically stores them in the computer.

[0020] Step 7: Decompose the video taken by the CCD camera into pictures, and use the digital image correlation algorithm. The corresponding pixel in the CCD camera is Y, in pixels. According to the ratio, the conversion coefficient is determined as K=S / Y, where S represents the calibrated length on the probe housing, in mm. In the actual detection process, the telescopic distance of the rigid probe is represented by p pixels in the CCD camera, in pixels. Then the actual rigid probe movement size L=K*p. The three-dimensional discrete points of the true value of the rigid probe telescopic distance are obtained by linear interpolation method to obtain the distribution characteristic parameters of the position, size and depth of the rust pits on the surface of the rusted sleeve to be tested, and then the distribution law of the rust pits on the sleeve surface can be statistically analyzed.

[0021] Through the above design scheme, the present invention can bring the following beneficial effects:

[0022] First, the device proposed in the present invention can realize the positioning and reconstruction of rust pits of grouting sleeve connectors with different geometric sizes and different degrees of corrosion, providing a basis for evaluating the degree of corrosion of large-scale and widespread prefabricated bridges and prefabricated building structures.

[0023] Second, the core idea of ​​the present invention is to convert the corrosion depth of the sleeve surface in the grouting sleeve connector into a high-precision identification of the extension and retraction amount of the probe probe using a digital image correlation algorithm, and cooperate with a high-precision electric translation stage and a Phytron ESS45 / 2.200.2,5 stepper motor with adjustable speed to achieve precise positioning of the distribution, size and shape of rust pits, thereby automatically and comprehensively acquiring the three-dimensional corrosion morphology data of the sleeve surface.

[0024] Third, the present invention can make up for the deficiency that the average corrosion degree of the sleeve obtained by the visual inspection method and the weighing method is difficult to reflect the degradation mechanism of the force transmission performance of the grouting sleeve connection caused by the uncertainty of corrosion, and underestimates the potential harm of corrosion to the mechanical properties of the assembled structure.

[0025] Fourth, the measuring device of the present invention has a simple structure, multiple parts can be disassembled and assembled, and it is easy to operate. While ensuring the accuracy of the measurement data, the cost of the measuring equipment is lower than that of the 3D laser scanning method and the ultrasonic detection method, and it can make up for the shortcomings that it may not be sensitive enough to certain types of corrosion (uniform corrosion) and cannot detect large-volume grouting sleeve connectors due to experimental conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 This is a schematic diagram of the structure of the device for measuring the corrosion characteristic parameters of the grouting sleeve connecting piece proposed by the present invention;

[0028] Figure 2 is a schematic diagram of the structure of the mobile device;

[0029] Figure 3 is a schematic structural diagram of a retractable probe device;

[0030] The markings in the attached drawings are as follows: 1-base; 2-connecting part of the grouting sleeve to be tested; 3-first support; 4-second support; 5a-first driving device; 5b-second driving device; 6-slide rail; 7-moving device; 7a-steel clamp; 7b-vertical slide rail; 7c-connecting plate; 7d-base plate; 8-CCD camera; 9-cantilever steel plate; 10-retractable probe device; 11-computer; 12-rigid probe; 13-probe housing; 14-spring. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In order to avoid confusing the essence of the present invention, well-known methods, processes, processes, components and circuits are not described in detail. It should be understood that the terms "first" and "second" are only used for descriptive purposes, and the features defined as "first" and "second" do not represent any order, quantity or importance, but are only used to distinguish different components.

[0032] See also Figures 1 to 3The device for measuring the corrosion characteristic parameters of the grouting sleeve connector proposed by the present invention comprises a base 1, a first driving device 5a, a second driving device 5b, a slide rail 6, a moving device 7, a CCD camera 8 and a retractable probe device 10, wherein the base 1 is provided with a clamping device for clamping the grouting sleeve connector 2 to be measured; the first driving device 5a is used to drive the grouting sleeve connector 2 to be measured to rotate around its own rotation axis; the CCD camera 8 and the retractable probe device 10 are fixed to the cantilever steel plate 9 by bolts, and the retractable probe device 10 and the CCD camera 8 are connected to the cantilever steel plate by the retractable probe device 10 and the CCD camera 8. 9 is rigidly connected to the moving device 7, and the moving device 7 includes a steel clamp 7a, a vertical slide rail 7b, a connecting plate 7c and a base plate 7d. In the moving device 7, the vertical slide rail 7b is fixed on the connecting plate 7c, the connecting plate 7c is connected to the output end of the second driving device 5b, and the connecting plate 7c is integrally formed with the base plate 7d. A slide groove matching the slide rail 6 is provided at the bottom of the base plate 7d. By adjusting the parameters of the second driving device 5b, the distance of a single movement of the moving device 7 along the slide rail 6 is adjusted. By controlling the switch of the second driving device 5b, the movement and stop of the moving device 7 are controlled. The cantilever steel plate 9 is fixed to the steel clamp 7a at the top of the moving device 7 by bolts. The steel clamp 7a can move up and down along the vertical slide rail 7b. When it moves to the position where the retractable probe device 10 works normally, it is fixed by bolts. The retractable probe device 10 and the CCD camera 8 move synchronously with the moving device 7, and the relative positions of the CCD camera 8 and the retractable probe device 10 remain unchanged during the movement. The rigid probe 12 of the retractable probe device 10 contacts the surface of the grouting sleeve connector 2 to be tested. The CCD camera 8 is connected to the computer 11. By controlling the CCD camera 8 to shoot the video of the entire process of the retractable probe device 10 telescopic deformation, the depth of the rust pit on the sleeve surface is obtained according to the proportional relationship between the pixel coordinates and the real coordinates. The second driving device 5b adopts a Phytron ESS45 / 2.200.2,5 stepper motor.

[0033] The clamping device includes a first support 3, a second support 4, a first clamping component and a second clamping component. The first support 3 and the second support 4 are installed on the base 1 by bolts. The first clamping component is detachably installed on the first support 3, and the second clamping component is detachably installed on the second support 4. The first driving device 5a is installed on the first support 3. The relative distance between the first support 3 and the second support 4 can be adjusted according to the size of the grouting sleeve connector 2 to be measured. The first clamping component and the second clamping component adopt spring chucks to meet the measurement requirements of grouting sleeve connectors 2 of different diameters to be measured. The spring chucks are commercially available products and will not be described in detail here. The first driving device 5 is installed on the first support 3. The first driving device 5a adopts a Phytron ESS45 / 2.200.2,5 stepping motor, and its rotation angle during the measurement process can be adjusted according to specific accuracy requirements. By matching the rotation speed of the Phytron ESS45 / 2.200.2,5 stepper motor and the distance of each movement of the moving device 7, the position of the rust pits on the surface of the grouting sleeve connector 2 to be tested and the three-dimensional geometric dimensions can be fully and accurately measured.

[0034] The rigid probe 12 is a rigid probe with a ball needle, and the ball needle can ensure that the rigid probe 12 moves smoothly on the surface of the sleeve.

[0035] The present invention also proposes a method for measuring characteristic parameters of corrosion of a grouting sleeve connector, comprising:

[0036] Step 1: Soak the grouting sleeve connector 2 to be tested in dilute hydrochloric acid with a mass concentration of 3.5%, remove rust and dry;

[0037] Step 2: Determine the starting point and end point of the measurement area on the surface of the grouting sleeve connector 2 to be measured and mark them;

[0038] Step three: fix the grouting sleeve connector 2 to be tested on the base 1 through the clamping device, and fix the CCD camera 8 and the retractable probe device 10 on the cantilever steel plate 9 through bolts. The retractable probe device 10 and the CCD camera 8 are rigidly connected through the cantilever steel plate 9 and the moving device 7, and move synchronously with the moving device 7. During the movement, the relative positions of the CCD camera 8 and the retractable probe device 10 remain unchanged, and can be fixed by bolts when moved to a position where the retractable probe device 10 can work normally. Make the rigid probe 12 contact with the starting point of the measuring area. At this time, the spring 14 in the retractable probe device 10 is in a normal working retracted state, and adjust the CCD camera 8 lens to clearly capture the entire rigid probe 12 and the calibrated length on the retractable probe device 10;

[0039] Step 4: According to the measurement accuracy requirements, adjust the parameters of the first driving device 5a and the second driving device 5b to determine the rotation speed of the grouting sleeve connector 2 to be measured and the translation distance of the mobile device 7 each time; adjust the shooting frame rate of the CCD camera 8 according to the measurement accuracy requirements;

[0040] Step 5: Control the first driving device 5a to rotate the grouting sleeve connector 2 to be tested 360 degrees at the rotation speed described in step 4. During the rotation of the grouting sleeve connector 2 to be tested, the rigid probe 12 contacts the surfaces of the grouting sleeve connector 2 with different corrosion conditions, and continuously expands and contracts through the spring 14 to reflect the size, depth and position of the rust pits on the sleeve surface of the grouting sleeve connector 2 to be tested, and obtain the detection data of the grouting sleeve connector 2 to be tested for one week, pause for 2s, and then control the movement of the moving device 7 through the second driving device 5b, and drive the CCD camera 8, the cantilever steel plate 9 and the retractable probe device 10 to move. The single translation distance is determined by the accuracy required for the measurement. After the movement is completed, pause for 2 seconds;

[0041] Step 6: Repeat step 5 continuously. When the rigid probe 12 of the retractable probe device 10 moves to the end point of the measuring area, the measurement is stopped. During the whole measuring process, the CCD camera 8 continuously takes videos and automatically stores them in the computer 11.

[0042] Step 7: Decompose the video captured by the CCD camera 8 into pictures, and use the digital image correlation algorithm. The probe housing 13 has a calibrated length in mm, with an accuracy of 0.001 mm. The corresponding pixel in the CCD camera 8 is Y in pixel. The conversion coefficient K is determined based on the ratio, K = S / Y, where S is the calibrated length; in the actual detection process, the probe telescopic distance is represented by p in the pixel of the CCD camera 8, with a unit of pixel, and the actual probe movement size L = K*p. The three-dimensional discrete points of the true value of the probe telescopic distance are obtained by linear interpolation method to obtain the distribution characteristic parameters of the position, size and depth of the rust pits on the surface of the rusted sleeve to be tested, and then the distribution law of the rust pits on the sleeve surface can be statistically analyzed.

[0043] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A device for measuring the corrosion characteristic parameters of a grouting sleeve connector, characterized in that: include: A base (1), a first drive device (5a), a second drive device (5b), a slide rail (6), a moving device (7), a CCD camera (8) and a retractable probe device (10), wherein the base (1) is provided with a clamping device for clamping a grouting sleeve connector (2) to be tested; the first drive device (5a) is used to drive the grouting sleeve connector (2) to be tested to rotate around its own rotation axis; the CCD camera (8) and the retractable probe device (10) are fixed to a cantilever steel plate (9) by bolts, and the relative positions of the CCD camera (8) and the retractable probe device (10) always remain unchanged; the CCD camera (8) is connected to a computer (11), and the CCD camera (8) is used to capture a video of the entire process of the retractable and retractable deformation of the retractable probe device (10); the retractable probe device (10) comprises a rigid probe (12), a probe housing (13) and a spring (14), wherein the spring (14) is arranged inside the probe housing (13), and The top of the spring (14) abuts against the inner top wall of the probe housing (13); the central axis of the rigid probe (12) and the central axis of the spring (14) are in a straight line, the top of the rigid probe (12) is fixedly connected to the spring (14), and the lower part of the rigid probe (12) extends out of the probe housing (13); during measurement, the rigid probe (12) contacts the surface of the grouting sleeve connector (2) to be measured; the probe housing (13) has a calibrated length for determining the conversion coefficient between the pixel of the CCD camera (8) and the actual distance of the up and down movement of the rigid probe (12); the cantilever steel plate (9) can move up and down in the vertical direction relative to the moving device (7) and can be fixed at a certain position of the moving device (7); the moving device (7) is slidably matched with the slide rail (6), the moving device (7) is connected to the second drive device (5b), and moves along the slide rail (6) under the drive of the second drive device (5b); the slide rail (6) is installed on the base (1).

2. The device for measuring the corrosion characteristic parameters of the grouting sleeve connector according to claim 1, characterized in that: The clamping device comprises a first support (3), a second support (4), a first clamping component and a second clamping component. The first support (3) and the second support (4) are mounted on a base (1) by means of bolts. The first clamping component is detachably mounted on the first support (3). The second clamping component is detachably mounted on the second support (4). The first driving device (5a) is mounted on the first support (3).

3. The device for measuring the corrosion characteristic parameters of the grouting sleeve connector according to claim 2, characterized in that: The first clamping member and the second clamping member are spring clamps.

4. The device for measuring the corrosion characteristic parameters of the grouting sleeve connector according to claim 2, characterized in that: The first driving device (5a) is a stepping motor.

5. The device for measuring the characteristic parameters of corrosion of grouting sleeve connectors according to claim 1, characterized in that: The moving device (7) comprises a steel clamp (7a), a vertical slide rail (7b), a connecting plate (7c) and a base plate (7d); the steel clamp (7a) is fastened to the cantilever steel plate (9) by bolts; the steel clamp (7a) is arranged on the vertical slide rail (7b); the steel clamp (7a) can move along the length direction of the vertical slide rail (7b) and be locked at different positions; the vertical slide rail (7b) is fixed to the base plate (7d) by the connecting plate (7c); the connecting plate (7c) and the base plate (7d) are integrally formed; the connecting plate (7c) is connected to the output end of the second driving device (5b); a slide groove matching the slide rail (6) is arranged at the bottom of the base plate (7d); the second driving device (5b) is used to drive the moving device (7) to move along the slide rail (6).

6. The device for measuring the characteristic parameters of corrosion of grouting sleeve connectors according to claim 5, characterized in that: The second driving device (5b) is a stepping motor.

7. The device for measuring the characteristic parameters of corrosion of grouting sleeve connectors according to claim 1, characterized in that: The rigid probe (12) is a rigid probe with a ball needle.

8. A method for measuring the characteristic parameters of corrosion of grouting sleeve connectors, characterized in that: The method is based on the device for measuring the corrosion characteristic parameters of the grouting sleeve connector according to claim 1, and specifically comprises: Step 1: soak the grouting sleeve connector (2) to be tested in dilute hydrochloric acid with a mass concentration of 3.5%, remove rust and dry; Step 2: Determine the starting point and the end point of the measurement area on the surface of the grouting sleeve connector (2) to be measured and mark them; Step 3: placing the grouting sleeve connector (2) to be tested on the device for measuring the characteristic parameters of rusting sleeve connectors, making the rigid probe (12) contact the starting point of the measuring area, and adjusting the lens of the CCD camera (8) to clearly photograph the entire rigid probe (12) and the calibrated length value on the probe housing (13); Step 4: According to the measurement accuracy requirements, adjust the parameters of the first driving device (5a) and the second driving device (5b), determine the rotation speed of the grouting sleeve connector (2) to be measured and the translation distance of the moving device (7) each time, and adjust the shooting frame rate of the CCD camera (8) according to the measurement accuracy requirements; Step 5: Control the first driving device (5a) to rotate the grouting sleeve connector (2) to be tested 360 degrees at the rotation speed described in step 4. During the rotation of the grouting sleeve connector (2) to be tested, the rigid probe (12) contacts the surface of the grouting sleeve connector (2) to be tested with different corrosion conditions, and continuously retracts and retracts through the spring (14) to reflect the size, depth and position of the rust pits on the sleeve surface of the grouting sleeve connector (2) to be tested, and obtain the detection data of the grouting sleeve connector (2) to be tested for one week, pause for 2 seconds, and then control the movement of the moving device (7) through the second driving device (5b), and drive the CCD camera (8), the cantilever steel plate (9) and the retractable probe device (10) to move. The single translation distance is determined by the accuracy required for the measurement. After the movement is completed, pause for 2 seconds; Step 6: Repeat step 5 continuously, and stop measuring when the rigid probe (12) moves to the end point of the measuring area. During the whole measuring process, the CCD camera (8) continuously takes video and automatically stores it in the computer (11); Step 7: Decompose the video captured by the CCD camera (8) into pictures, and use a digital image correlation algorithm. The pixel corresponding to it in the CCD camera (8) is Y, with a unit of pixel; determine the conversion coefficient K=S / Y based on the ratio thereof, wherein S represents the calibrated length on the probe housing, with a unit of mm. In the actual detection process, the telescopic distance of the rigid probe (12) is represented by a pixel p in the CCD camera (8), with a unit of pixel. Then, the actual rigid probe (12) movement size L=K*p, and the three-dimensional discrete points of the true value of the telescopic distance of the rigid probe (12) are obtained by using a linear interpolation method to obtain the distribution characteristic parameters of the position, size and depth of the rust pits on the surface of the rusted sleeve to be tested, and then the distribution law of the rust pits on the sleeve surface can be statistically analyzed.

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