System and method for testing mechanical properties of in-service plastic pipeline based on indentation method

Abstract

The invention discloses a system and a method for testing mechanical properties of an in-service plastic pipeline based on an indentation method. The test system comprises two groups of fixed ring assemblies which are oppositely distributed, movable ring assemblies which are coaxially distributed on the inner sides of the fixed ring assemblies and are in running fit with the inner side end surfaces of the fixed ring assemblies, and a first power mechanism which is used for driving the movable ring assemblies to rotate; the fixed ring assembly is used for being fixed outside a tested in-service plastic pipeline; a beam body is connected between the two groups of moving ring assemblies, the indentation mechanism is in sliding fit with the beam body, and the second power mechanism is used for driving the indentation mechanism to move along the beam body. The device is used for solving the problem that in the prior art, cutting sampling is needed, and online detection of the mechanical property of the in-service plastic pipeline is difficult, and the purpose that the mechanical property of the in-service plastic pipeline can be effectively detected can be achieved.

Description

Technical Field

[0001] This invention relates to the field of mechanical performance testing of in-service plastic pipes, and specifically to a mechanical performance testing system and method for in-service plastic pipes based on the indentation method. Background Technology

[0002] Plastic pipes, as crucial pressure-bearing carriers in lifeline engineering projects, have occupied a vast market share since their gradual application in the 1930s and 40s. Compared to metal pipes, plastic pipes offer advantages such as lower density, ease of processing, better insulation, corrosion resistance, superior seismic performance, longer lifespan, convenient installation, and lower cost. Therefore, they are widely used as critical pressure-bearing structures in lifeline projects such as urban gas pipelines and water supply pipelines. Conducting long-term performance evaluations of plastic pipes not only involves property safety but also directly relates to the safety of lives of residents along the pipelines. During long-term operation, plastic pressure pipes inevitably experience material aging due to external environmental factors, leading to performance degradation (such as a significant decrease in mechanical properties), and in severe cases, they may no longer be able to withstand the internal medium pressure.

[0003] During the production of plastic pipes, they need to go through processing techniques such as injection molding and extrusion, as well as the mixing and dispersion of additives. These processes can easily lead to non-uniformity in the internal structure of the material (such as molecular orientation and crystallization state) or components (such as additive distribution) in the axial and circumferential directions, resulting in local differences in their mechanical properties, which increases the complexity of evaluating the performance of plastic pipes.

[0004] Current research on the mechanical properties of plastic pipes mostly involves measuring relevant parameters through indoor tests such as tensile, impact, and bending after local sampling of the pipe material. However, with the increasing demands for pipe performance evaluation, the limitations of these traditional methods are becoming increasingly apparent: on the one hand, existing technologies require cutting the pipe for sampling, making them unsuitable for online testing of in-service pipes; on the other hand, local sampling cannot reflect material non-uniformity caused by manufacturing processes, nor can it characterize the overall performance degradation trend within a certain area.

[0005] While some existing technologies disclose methods for inspecting in-service pipelines, most of these technologies are only applicable to metal pipelines with good uniformity, and each inspection can only target a single measuring point. Inspecting multiple measuring points requires frequent installation and disassembly, making them unsuitable for detecting the non-uniformity of mechanical properties and assessing performance degradation trends in in-service plastic pipelines. Therefore, these existing technologies cannot meet the inspection needs of plastic pipelines with significant non-uniformity issues. Summary of the Invention

[0006] This invention provides a mechanical property testing system and method for in-service plastic pipes based on the indentation method, which solves the problem that existing technologies require cutting and sampling and are difficult to conduct online testing of the mechanical properties of in-service plastic pipes, thereby achieving the goal of effectively testing the mechanical properties of in-service plastic pipes.

[0007] This invention is achieved through the following technical solution:

[0008] A mechanical performance testing system for in-service plastic pipes based on indentation method includes two sets of relatively distributed fixed ring assemblies, a rotating ring assembly coaxially distributed inside the fixed ring assembly and rotatably engaged with the inner end face of the fixed ring assembly, and a first power mechanism for driving the rotating ring assembly to rotate; the fixed ring assembly is used to fix it to the outside of the in-service plastic pipe under test.

[0009] The beam connecting the two sets of moving ring assemblies also includes an indentation mechanism that slides on the beam and a second power mechanism for driving the indentation mechanism to move along the beam.

[0010] To address the problems of existing technologies requiring cutting and sampling, and the difficulty in online testing of the mechanical properties of in-service plastic pipes, this invention first proposes a mechanical property testing system for in-service plastic pipes based on the indentation method. This system includes two sets of relatively distributed fixed-ring assemblies. Each fixed-ring assembly has a rotating ring assembly rotatably fitted to its inner side. The two rotating ring assemblies are connected by several beams. The pipe between the two rotating ring assemblies is within the measurement range of this system. The inner side of the fixed-ring assembly refers to the axial sidewall of one fixed-ring assembly facing the other.

[0011] In practical use, the testing system of this application is installed on the in-service plastic pipe to be tested, with both fixed ring assemblies temporarily fixed to the outside of the pipe. Then, the moving ring assembly is adjusted via the first power mechanism to position the indentation mechanism in the desired circumferential orientation; the indentation mechanism is then adjusted via the second power mechanism to position it in the desired axial position. The indentation mechanism is then activated to apply pressure to the outer wall of the in-service plastic pipe, and pressure and displacement data are recorded. The mechanical properties of a single measuring point are determined based on the indentation method. Subsequently, while keeping the two fixed ring assemblies stationary, the measuring point position of the indentation mechanism can be flexibly adjusted within the area between the two moving ring assemblies via the first power mechanism and / or the second power mechanism to achieve continuous testing of the mechanical properties of multiple points until all preset measuring points of the current pipe section have been tested.

[0012] This application abandons the existing technical approach of cutting and sampling plastic pipes for testing, and achieves online testing of in-service plastic pipes through the indentation method. This is more suitable for the routine inspection of lifeline projects such as urban gas pipelines and water supply pipelines. Furthermore, this application can conduct tests at any point on a pipe section within a certain length range, meaning that a large number of testing points can be completed with a single installation, eliminating the need for frequent disassembly and reassembly. This meets the requirements for testing the mechanical non-homogeneity of in-service plastic pipes and is more suitable for online testing of plastic pipes with strong non-homogeneity. This application enables rapid, large-scale mechanical performance testing of in-service plastic pipes, allowing personnel to promptly grasp the performance non-homogeneity and performance degradation trends of plastic pipes. This provides strong support for ensuring the safe operation of urban gas pipelines and water supply pipelines, and further guarantees the safety of life and property of residents along the pipelines.

[0013] Furthermore, the fixed ring assembly includes two first semi-circular components, each of which has a first threaded hole, a first pin hole, and a first positioning pin on its circumferential end face. The two first semi-circular components are detachably connected by bolts passing through the first threaded holes, and when connected, the first pin holes of the two first semi-circular components cooperate with the first positioning pins.

[0014] When installing the fixed ring assembly, this solution involves placing the two first semi-circular components against the outer walls of the plastic pipe, aligning the first pin hole of one first semi-circular component with the first locating pin of the other. Once the first locating pin is inserted into the corresponding first pin hole, the first threaded holes on the two first semi-circular components are aligned. By screwing in the matching bolts and tightening, a temporary connection between the two first semi-circular components is achieved. This solution facilitates the rapid connection of the fixed ring assembly to in-service plastic pipes, enabling extensive mechanical testing without interfering with normal operation.

[0015] Furthermore, the first semi-circular component is provided with a plurality of radially extending second threaded holes, and also includes a clamping bolt that matches the second threaded holes and an arc-shaped clamping plate that is rotatably fitted at the inner diameter end of the clamping bolt.

[0016] This solution involves screwing the clamping bolt into the second threaded hole. The inner diameter end of the clamping bolt is located inside the fixed ring assembly and is rotatably connected to an arc-shaped clamping plate. Therefore, by simply rotating the clamping bolt, the radial depth of the arc-shaped clamping plate can be infinitely adjusted, thereby adapting to plastic pipes with different outer diameters and significantly improving the versatility of this application.

[0017] Furthermore, a first bearing is provided on the inner end face of the first semi-circular component, and the outer end face of the dynamic ring assembly has a groove that matches the first bearing.

[0018] The radial outer wall of the first semi-circular component is further provided with an outwardly protruding support block, and a through hole is formed on the support block, the axis of which is parallel to the axis of the first semi-circular component; it also includes a tie rod that matches the through hole. For the two sets of opposing fixed ring assemblies, their respective support blocks are directly opposite each other. By connecting the two corresponding support blocks through the tie rod, the two sets of fixed ring assemblies can be fixedly connected, further improving the overall usability and stability of this application.

[0019] In this design, the inner end face of the first semi-circular component refers to the end face connected to the rotating ring assembly along the axial direction. A first bearing is installed on this end face and engages with the rotating ring assembly through a slot, thereby achieving rotational engagement between the rotating ring assembly and the fixed ring assembly.

[0020] Furthermore, the moving ring assembly includes two second semi-circular components, the circumferential end faces of which are provided with a third threaded hole, a second pin hole, and a second positioning pin; the two second semi-circular components are detachably connected by bolts passing through the third threaded holes, and when connected, the second pin holes of the two second semi-circular components cooperate with the second positioning pins.

[0021] During the installation of the rotating ring assembly, this solution involves placing two second semi-circular components against the outer walls of the plastic pipe on both sides, achieving a rotatable engagement with the corresponding rotating ring assembly. The second pin hole of one second semi-circular component aligns with the second locating pin of the other, ensuring the second locating pin enters its corresponding second pin hole. At this point, the third threaded holes on the two second semi-circular components are aligned. Screwing in matching bolts and tightening them achieves a temporary connection between the two second semi-circular components. This solution facilitates rapid installation of the rotating ring assembly, enabling extensive mechanical testing without interfering with normal pipeline operation.

[0022] Furthermore, the first power mechanism includes a half gear fixedly sleeved on the outside of the second semi-circular component, a transmission gear meshing with the half gear, and a handle for driving the transmission gear to rotate; when the two second semi-circular components are connected, the two half gears are spliced ​​together to form a complete gear.

[0023] When the circumferential orientation of the indentation mechanism needs to be adjusted, the handle is manually turned, which drives the transmission gear to rotate, thereby driving the half gear and the second semi-circular component to rotate synchronously, realizing the overall rotation of the moving ring assembly. This scheme is beneficial for ensuring the indentation method can be used to detect measuring points in any circumferential orientation.

[0024] Furthermore, the second power mechanism includes a transverse guide rail disposed on the beam, a connecting plate slidably fitted on the transverse guide rail, and a first motor for driving the connecting plate to slide along the transverse guide rail; the indentation mechanism is mounted on the connecting plate.

[0025] When it is necessary to adjust the axial position of the indentation mechanism, the connecting plate is moved to the set position along the transverse guide rail by the first motor. This allows for flexible adjustment of the axial position of the indentation mechanism on the pipeline, which is beneficial for ensuring that the indentation method can be used to detect any axial position of the measuring point between the two sets of moving ring components.

[0026] Furthermore, the indentation mechanism includes a longitudinal base plate disposed on the connecting plate, a longitudinal guide rail located on the surface of the longitudinal base plate, a mounting plate slidably fitted on the longitudinal guide rail, a second motor for driving the mounting plate to slide along the longitudinal guide rail, and an indenter for applying pressure.

[0027] When installing or removing the testing system of this application, the mounting plate is driven by the second motor to slide radially outward, keeping the indenter as far away as possible from the plastic pipe being tested, thereby reducing the risk of unnecessary damage to the pipe or the indenter. After the indentation mechanism is adjusted to the correct position, this scheme uses the second motor to drive the mounting plate to slide radially inward, so that the indenter contacts or is about to release from the plastic pipe being tested, preparing for subsequent indentation testing.

[0028] Furthermore, the indentation mechanism also includes a piezoelectric stack assembly disposed on the mounting plate and a sensor assembly for monitoring the pressure and displacement of the indenter head; the indenter head is connected to the piezoelectric stack assembly and extends radially inward along the pipe; the piezoelectric stack assembly includes a plurality of piezoelectric ceramic sheets connected in series by flexible hinges.

[0029] Traditional indentation methods are designed for metal pipes, requiring a large torque and measurement range from the indentation mechanism to meet the indentation requirements. However, for indentation testing of in-service plastic pipes, existing indentation mechanisms, due to their softer material compared to metal, often produce excessive torque and displacement, failing to meet the needs of plastic pipes and potentially causing excessive indentation that can disrupt normal operation or even damage the pipes. To overcome these issues, this solution uses a piezoelectric stack assembly composed of connected piezoelectric ceramic sheets as the driving element to provide the driving voltage, generating a small deformation. This small deformation is applied to the indenter, creating a micron-level indentation on the outer wall of the tested plastic pipe. The magnitude of the force and the depth of the indentation are recorded by a sensor. This indentation method has the advantages of rapid response, high accuracy, stability and real-time performance; moreover, it can generate small displacements with low speed and high torque, while having excellent resolution, which significantly improves the accuracy of indentation operations. It is more suitable for online testing of in-service plastic pipes that contain fluid media inside. Under the premise of being able to generate indentations stably, it can ensure operational safety and reduce the operational risks of online detection.

[0030] The test method based on the in-service plastic pipe mechanical property testing system in this application includes the following steps:

[0031] S1. Install the test system on the in-service plastic pipe to be tested;

[0032] S2. Adjust the moving ring assembly using the first power mechanism to position the indentation mechanism in the desired circumferential orientation; adjust the indentation mechanism using the second power mechanism to position the indentation mechanism in the desired axial position.

[0033] S3. Start the indentation mechanism to apply pressure to the outer wall of the in-service plastic pipe being tested, and record the pressure and displacement data;

[0034] S4. Change to different measuring points and repeat steps S2 to S3 until all set measuring points of the current pipe section have been tested; disassemble the test system.

[0035] Compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0036] 1. The present invention provides a mechanical performance testing system and method for in-service plastic pipes based on the indentation method. This invention completely abandons the technical approach of disassembling or cutting plastic pipes for mechanical performance testing, which requires disassembly or cutting for sampling in the prior art. The indentation method enables online testing of in-service plastic pipes, which is more suitable for daily testing of lifeline projects such as urban gas pipelines and water supply pipelines.

[0037] 2. The present invention provides a mechanical performance testing system and method for in-service plastic pipes based on the indentation method, which can conduct tests on any point on a pipe section within a certain length range. A large number of test points can be tested with a single installation without frequent disassembly and assembly, and can meet the online testing requirements for the heterogeneous mechanical properties of in-service plastic pipes.

[0038] 3. The present invention provides a mechanical performance testing system and method for in-service plastic pipes based on the indentation method, which can quickly conduct large-scale mechanical performance testing on in-service plastic pipes. This allows staff to promptly grasp the heterogeneity and mechanical performance degradation trend of plastic pipes, providing strong support for ensuring the safe operation of urban gas pipelines, water supply pipelines, etc., and further guaranteeing the safety of life and property of residents along the pipelines.

[0039] 4. The present invention provides a mechanical performance testing system and method for in-service plastic pipes based on the indentation method, which can be adapted to plastic pipes with different outer diameters and has high versatility.

[0040] 5. The present invention provides a mechanical property testing system and method for in-service plastic pipes based on indentation. The indentation method provided has the advantages of rapid response speed, high accuracy, stability and real-time performance; it can also generate small displacements with low speed and high torque, and has excellent resolution, which significantly improves the accuracy of indentation operation. It is more suitable for online testing of in-service plastic pipes with fluid media inside. Under the premise of being able to generate indentations stably, it can ensure operational safety and reduce the operational risks of prior testing. Attached Figure Description

[0041] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0042] Figure 1 This is a front view of a specific embodiment of the present invention;

[0043] Figure 2 This is a top view of the second power mechanism in a specific embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of the structure of the first semi-circular component in a specific embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of the inner end face of the fixed ring assembly in a specific embodiment of the present invention;

[0046] Figure 5 This is a schematic diagram of the outer end face of the fixed ring assembly in a specific embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram of the structure of the second semi-circular component in a specific embodiment of the present invention.

[0048] The attached diagram shows the markings and corresponding component names:

[0049] 1-Fixed ring assembly, 2-First bolt, 3-Moving ring assembly, 4-Indenter, 5-Clamping bolt, 6-Beam, 7-Sensor assembly, 8-Mounting plate, 9-Longitudinal guide rail, 10-Longitudinal base plate, 11-Second motor, 12-Second bolt, 13-Third bolt, 14-Fourth bolt, 15-Piezoelectric stack assembly, 16-Transmission gear, 17-Support block, 18-Second bearing, 19-Handle, 20-First bearing, 21-Flexible hinge, 22- 23-Connecting plate, 24-Transverse base plate, 25-Transverse guide rail, 26-Ball screw, 27-Coupling, 28-Motor base, 29-First motor, 30-Eccentric shaft, 31-First locating pin, 32-First pin hole, 33-Second threaded hole, 34-Second locating pin, 35-Second pin hole, 36-Half gear, 37-Slot, 38-First threaded hole, 39-Arc-shaped clamping plate, 40-Through hole, 41-Third threaded hole, 42-Opening. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are for explaining the invention only and are not intended to limit the invention. In the description of this application, it should be understood that terms such as "front," "rear," "left," "right," "upper," "lower," "vertical," "horizontal," "high," "low," "inner," and "outer," indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application.

[0051] Example 1:

[0052] like Figures 1 to 6 The in-service plastic pipe mechanical performance testing system based on indentation method is shown, including two sets of relatively distributed fixed ring components 1, a rotating ring component 3 coaxially distributed inside the fixed ring components 1 and rotatably engaged with the inner end face of the fixed ring components 1, and a first power mechanism for driving the rotating ring component 3 to rotate; the fixed ring components 1 are used to fix the in-service plastic pipe under test to the outside.

[0053] The two sets of moving ring assemblies 3 are connected to the beam 6, and also include an indentation mechanism that slides on the beam 6 and a second power mechanism for driving the indentation mechanism to move along the beam 6.

[0054] The fixed ring assembly 1 includes two first semi-circular components. The circumferential end face of the first semi-circular components is provided with a first threaded hole 38, a first pin hole 32, and a first positioning pin 31. The two first semi-circular components are detachably connected by bolts passing through the first threaded hole 38. When connected, the first pin hole 32 of the two first semi-circular components and the first positioning pin 31 cooperate with each other.

[0055] The first semi-circular component is provided with a plurality of radially extending second threaded holes 33, and also includes clamping bolts 5 that match the second threaded holes 33, and an arc-shaped clamping plate 39 that is rotatably fitted at the inner diameter end of the clamping bolts 5. In this embodiment, the number of second threaded holes 33 is two.

[0056] The inner end face of the first semi-circular component is provided with a first bearing 20, and the outer end face of the moving ring assembly 3 has a groove 37 that matches the first bearing 20.

[0057] The radial outer wall of the first semi-circular component is also provided with an outwardly protruding support block 17, and a through hole 40 is opened on the support block 17. The axis of the through hole 40 is parallel to the axis of the first semi-circular component; it also includes a pull rod 22 that matches the through hole 40.

[0058] The moving ring assembly 3 includes two second semi-circular components. The circumferential end face of the second semi-circular components is provided with a third threaded hole 41, a second pin hole 35, and a second positioning pin 34. The two second semi-circular components are detachably connected by bolts passing through the third threaded hole 41. When connected, the second pin hole 35 of the two second semi-circular components and the second positioning pin 34 cooperate with each other.

[0059] In this embodiment, the slot 37 is disposed on the axial inner wall of the second semi-circular component.

[0060] In this embodiment, the two first semi-circular components are detachably connected by the first bolt 2 passing through the first threaded hole 38; similarly, the two second semi-circular components are detachably connected by the first bolt 2 passing through the third threaded hole 41.

[0061] Preferably, the inner end face of the first semi-circular component is provided with a plurality of axial holes, and an eccentric shaft 30 is installed inside them. The axial holes and the eccentric shaft 30 are transition fits, and a first bearing 20 is installed at the end of the eccentric shaft 30; the first bearing 20 is a support ball bearing.

[0062] Preferably, the axial inner wall end face of the second semi-circular component is provided with an opening 42 that matches the beam 6, for cooperating with the beam 6 for axial hole transition fit.

[0063] Example 2

[0064] A mechanical property testing system for in-service plastic pipes based on the indentation method, as described in Example 1, such as... Figures 1 to 6 As shown, the first power mechanism includes a half gear 36 fixedly sleeved on the outside of the second semi-circular component, a transmission gear 16 meshing with the half gear 36, and a handle 19 for driving the transmission gear 16 to rotate; when the two second semi-circular components are connected, the two half gears 36 are spliced ​​together to form a complete gear.

[0065] The second power mechanism includes a transverse guide rail 25 disposed on the beam 6, a connecting plate 23 slidably fitted on the transverse guide rail 25, and a first motor 29 for driving the connecting plate 23 to slide along the transverse guide rail 25; the indentation mechanism is mounted on the connecting plate 23.

[0066] The indentation mechanism includes a longitudinal base plate 10 disposed on the connecting plate 23, a longitudinal guide rail 9 located on the surface of the longitudinal base plate 10, a mounting plate 8 slidably fitted on the longitudinal guide rail 9, a second motor 11 for driving the mounting plate 8 to slide along the longitudinal guide rail 9, and an indenter 4 for applying pressure.

[0067] In this embodiment, the indentation mechanism further includes a piezoelectric stack assembly 15 disposed on the mounting plate 8 and a sensor assembly 7 for monitoring the pressure and displacement of the indenter 4; the indenter 4 is connected to the piezoelectric stack assembly 15 and extends radially inward along the pipe; the piezoelectric stack assembly 15 includes a plurality of piezoelectric ceramic sheets connected in series via flexible hinges 21. The sensor assembly 7 in this embodiment includes a displacement sensor and a pressure sensor.

[0068] Preferably, a transverse base plate 24 is fixedly connected to the connecting plate 23, and the longitudinal base plate 10 is mounted on the transverse base plate 24.

[0069] Preferably, the handle 19 passes through the support block 17 via the second bearing 18 and is rotatably engaged with the support block 17.

[0070] Preferably, the second motor 11 is mounted on the longitudinal base plate 10 by the second bolt 12; the longitudinal guide rail 9 is mounted on the longitudinal base plate 10 by the third bolt 13; the mounting plate 8 is slidably engaged with the longitudinal guide rail 9 by a slider, and the slider is connected to the mounting plate 8 by the fourth bolt 14.

[0071] Preferably, the first motor 29 is installed in the motor base 28, and the output end of the first motor 29 is connected to the ball screw 26 through the coupling 27, and the connecting plate 23 is driven to slide along the transverse guide rail 25 through the ball screw 26.

[0072] Example 3

[0073] A method for testing the mechanical properties of in-service plastic pipes based on indentation, employing methods such as... Figures 1 to 6 The test system implementation shown includes the following steps:

[0074] S1. Install the test system on the in-service plastic pipe to be tested;

[0075] S2. Adjust the moving ring assembly 3 using the first power mechanism to position the indentation mechanism in the desired circumferential orientation; adjust the indentation mechanism using the second power mechanism to position the indentation mechanism in the desired axial position.

[0076] S3. Start the indentation mechanism to apply pressure to the outer wall of the in-service plastic pipe being tested, and record the pressure and displacement data;

[0077] S4. Change to different measuring points and repeat steps S2 to S3 until all set measuring points of the current pipe section have been tested; disassemble the test system.

[0078] In a more preferred embodiment, step S1 specifically includes:

[0079] S101. The two first semi-circular components of the fixed ring assembly 1 are fitted and sealed on both sides of the in-service plastic pipe to be tested through the cooperation of the first positioning pin 31 and the first pin hole 32, and the two first semi-circular components of the fixed ring assembly 1 are fixed with the first bolt 2.

[0080] S102. Screw the clamping bolt 5 into the second threaded hole 33;

[0081] S103. The beam body 6 and the second semi-circular component of the moving ring assembly 3 are fixed by the shaft hole transition fit through the opening 42; the two second semi-circular components are sealed on both sides of the measuring pipe by the matching sleeve of the second positioning pin 34 and the second pin hole 35, and the two second semi-circular components are fixed by the first bolt 2. At the same time, they are clamped on the first bearing 20 of the fixed ring assembly through the slot 37 to achieve mutual cooperation with the fixed ring assembly 1.

[0082] S104, rotate the clamping bolt 5, adjust the extension length of the arc-shaped clamping plate 39, and lock the clamping bolt 5 after ensuring that the fixed ring assembly 1 is coaxial with the plastic pipe to be tested;

[0083] S105. Pass the pull rod 22 through the support block 17 and tighten the nuts at both ends of the pull rod 22;

[0084] S106. Install the indentation mechanism and the second power mechanism on beam 6 to complete the installation.

[0085] In a more preferred embodiment, the method for installing the indentation mechanism and the second power mechanism on the beam 6 includes:

[0086] S1061. A transverse guide rail 25 is fixedly connected to the beam 6, and a sliding connection plate 23 is installed on the transverse guide rail 25.

[0087] S1062. Install components such as ball screw 26, coupling 27 and first motor 29 so that the first motor 29 can drive the connecting plate 23 to slide.

[0088] S1063. Install an indentation mechanism on the connecting plate 2.

[0089] It should be noted that during the above installation process, it is necessary to ensure that the two sets of half gears 36 are spliced ​​into a complete external gear, and that the external gear meshes with the transmission gear 16.

[0090] It should be noted that during the above installation process, the pressure head 4 is moved away from the pipe surface by the second motor 11; after the installation is completed, the pressure head 4 is brought into contact with the pipe surface by the second motor 11.

[0091] Furthermore, the activation of the indentation mechanism in step S3 refers to energizing the piezoelectric stack assembly 15. The minute deformations generated by each piezoelectric ceramic sheet are transmitted to the indenter 4, applying indentation to the pipe under test. The sensor assembly 7 begins recording the indentation depth and load data. When the indentation depth or load reaches a set threshold, the power supply to the piezoelectric stack assembly 15 is turned off. The piezoelectric stack assembly 15 resets, the indenter 4 is unloaded, and the sensor assembly 7 outputs the measurement results.

[0092] In this application, the area between the two sets of dynamic ring components 3 is the measurable range. If a test point is located outside the aforementioned measurable range, simply drive the indenter 4 of the indentation mechanism outward away from the pipe surface, loosen the clamping bolts 5, and move the test system of this application laterally on the pipe under test until the test point enters the measurable range. Then, retighten the clamping bolts 5 to continue the required testing.

[0093] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0094] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Additionally, the term "connection" as used herein, unless otherwise specified, can refer to a direct connection or an indirect connection via other components.

Claims

1. A mechanical property testing system for in-service plastic pipes based on indentation method, characterized in that, It includes two sets of relatively distributed fixed ring assemblies (1), a rotating ring assembly (3) coaxially distributed inside the fixed ring assembly (1) and rotatably engaged with the inner end face of the fixed ring assembly (1), and a first power mechanism for driving the rotating ring assembly (3) to rotate; the fixed ring assembly (1) is used to fix it to the outside of the tested in-service plastic pipe; The two sets of moving ring assemblies (3) are connected to a beam (6), and also include an indentation mechanism that slides on the beam (6) and a second power mechanism for driving the indentation mechanism to move along the beam (6).

2. The in-service plastic pipe mechanical property testing system based on indentation method according to claim 1, characterized in that, The fixed ring assembly (1) includes two first semi-circular components. The circumferential end face of the first semi-circular components is provided with a first threaded hole (38), a first pin hole (32), and a first positioning pin (31). The two first semi-circular components are detachably connected by a bolt passing through the first threaded hole (38). When connected, the first pin hole (32) of the two first semi-circular components and the first positioning pin (31) cooperate with each other.

3. The in-service plastic pipe mechanical property testing system based on indentation method according to claim 2, characterized in that, The first semi-circular component is provided with a plurality of radially extending second threaded holes (33), and also includes a clamping bolt (5) that matches the second threaded holes (33) and an arc-shaped clamping plate (39) that is rotatably fitted at the inner diameter end of the clamping bolt (5).

4. The in-service plastic pipe mechanical property testing system based on indentation method according to claim 2, characterized in that, The inner end face of the first semi-circular component is provided with a first bearing (20), and the outer end face of the dynamic ring assembly (3) has a groove (37) that matches the first bearing (20). The radial outer wall of the first semi-circular component is also provided with an outwardly protruding support block (17), and a through hole (40) is opened on the support block (17). The axis of the through hole (40) is parallel to the axis of the first semi-circular component; it also includes a pull rod (22) that matches the through hole (40).

5. The in-service plastic pipe mechanical property testing system based on indentation method according to claim 1, characterized in that, The moving ring assembly (3) includes two second semi-circular components. The circumferential end face of the second semi-circular components is provided with a third threaded hole (41), a second pin hole (35), and a second positioning pin (34). The two second semi-circular components are detachably connected by a bolt passing through the third threaded hole (41). When connected, the second pin hole (35) of the two second semi-circular components and the second positioning pin (34) cooperate with each other.

6. The in-service plastic pipe mechanical property testing system based on indentation method according to claim 5, characterized in that, The first power mechanism includes a half gear (36) fixedly sleeved on the outside of the second semi-circular component, a transmission gear (16) meshing with the half gear (36), and a handle (19) for driving the transmission gear (16) to rotate; when the two second semi-circular components are connected, the two half gears (36) are spliced ​​into a complete gear.

7. The in-service plastic pipe mechanical property testing system based on indentation method according to claim 1, characterized in that, The second power mechanism includes a transverse guide rail (25) disposed on the beam (6), a connecting plate (23) slidably fitted on the transverse guide rail (25), and a first motor (29) for driving the connecting plate (23) to slide along the transverse guide rail (25); the indentation mechanism is mounted on the connecting plate (23).

8. The in-service plastic pipe mechanical property testing system based on indentation method according to claim 1, characterized in that, The indentation mechanism includes a longitudinal base plate (10) disposed on the connecting plate (23), a longitudinal guide rail (9) located on the surface of the longitudinal base plate (10), a mounting plate (8) slidably fitted on the longitudinal guide rail (9), a second motor (11) for driving the mounting plate (8) to slide along the longitudinal guide rail (9), and an indenter (4) for applying pressure.

9. The in-service plastic pipe mechanical property testing system based on indentation method according to claim 8, characterized in that, The indentation mechanism also includes a piezoelectric stack assembly (15) disposed on the mounting plate (8) and a sensor assembly (7) for monitoring the pressure and displacement of the indenter (4); the indenter (4) is connected to the piezoelectric stack assembly (15) and the indenter (4) extends radially inward along the pipe; the piezoelectric stack assembly (15) includes a plurality of piezoelectric ceramic sheets connected in series by flexible hinges (21).

10. A test method for an in-service plastic pipe mechanical property testing system based on indentation method as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Install the test system on the in-service plastic pipe to be tested; S2. Adjust the moving ring assembly (3) through the first power mechanism to place the indentation mechanism in the required circumferential orientation; adjust the indentation mechanism through the second power mechanism to place the indentation mechanism in the required axial position; S3. Start the indentation mechanism to apply pressure to the outer wall of the in-service plastic pipe being tested, and record the pressure and displacement data; S4. Change to different measuring points and repeat steps S2-S3 until all set measuring points of the current pipe section have been tested; disassemble the test system.

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