An experimental device and testing method for mechanical property and leakage testing of water supply pipeline joints

Abstract

The application discloses an experimental device and a testing method for mechanical property and leakage testing of a water supply pipeline joint, and the experimental device comprises five parts of a testing pipeline, a pipe end fixing device, a water pressure loading device, a pipeline deformation testing device and a water flow information testing device. The pipe end fixing device comprises a flange, a rib plate, a steel plate and a short pipe (compared with the pipe section). The water pressure loading device comprises a valve, a water pipe, a water pump and a water tank, and realizes the circulating flow of water in the pipe through the water pump pressurization. The pipeline deformation testing device comprises a wire pulling type displacement meter and a strain gauge to measure the deformation of the joint and the pipe body. The application can effectively measure the dynamic changes of the joint stiffness and the leakage flow, thereby improving the experimental efficiency; meanwhile, the application has good compatibility for different types of water supply pipelines, can effectively reduce the economic cost, and more importantly, the application can reveal the relationship between the mechanical property parameters of the pipeline joint and the functional parameters of the pipeline joint, and provides a calculation basis for the functional evaluation of the pipeline network under the earthquake action.

Description

TECHNICAL FIELD

[0001] The present application relates to an experimental device and a testing method for performance testing of a water supply pipeline joint, in particular to an experimental device and a testing method for mechanical performance and leakage testing of a water supply pipeline joint. BACKGROUND

[0002] The water supply pipeline is an important part of the urban water supply network and undertakes the important task of water transportation and distribution. It usually has the characteristics of long service time and significant environmental corrosion, and its performance degradation is obvious. Especially under the action of earthquake, the water supply pipeline often appears serious damage, leading to lack of urban water supply, thereby significantly affecting the functions of emergency rescue, fire fighting and other functions after the disaster. For example, in the 1976 Tangshan earthquake, 102 damage points of 3.4 km of cast iron pipeline were found, with an average of 30 points / km. In the 2008 Wenchuan earthquake, the leakage rate of the water supply network in Dujiangyan City was as high as 80%, and after 69 times of pipeline repair in the city, the leakage rate was still 60%. Therefore, it is of great significance to carry out research on the seismic performance of water supply pipeline.

[0003] There are many types of water supply pipelines, but they can be classified into two categories according to the connection method. The first type is sectional water supply pipeline, such as cast iron pipe, ductile cast iron pipe, etc. The second type is integral pipeline composed of steel pipe, PVC pipe, etc. Since sectional pipeline is the main part of water supply network, it has attracted extensive attention and research. The research focus of this type of pipeline is the mechanical properties and leakage model of the joint. Common methods include theoretical analysis, experimental testing, finite element simulation, etc.

[0004] The existing pipeline joint test experiment usually only tests the mechanical properties of the pipeline joint, such as document [1] , or can only realize the qualitative description of the leakage function of the pipeline joint and cannot establish the quantitative analysis of the leakage law of the pipeline joint, such as document [2] , especially cannot reflect the change of the joint function caused by the change of the mechanical properties in the deformation process of the joint, resulting in low experimental efficiency, unable to consider the dynamic change of the stress characteristics of the pipeline joint and the leakage of the joint, unable to reflect the change characteristics of the leakage flow of the pipeline structure in the process of tensile deformation, and more importantly, unable to reveal the relationship between the mechanical performance parameters of the pipeline joint and the function parameters of the pipeline joint, so the present application arises at the historic moment.

[0005] The reference related to the present application is:

[0006] Beijing University of Technology. A test device capable of axial reciprocating loading: China, CN202110026439.1[P]. 2021-04-09

[0007] Zhong Z L, Zhang Y B, Li J Q, et al. Bending performance test of nodular cast iron pipe joint[J]. Journal of Harbin Institute of Technology, 2022. DOI:10.11918 / 202206020. SUMMARY

[0008] In view of the deficiencies of the existing experimental device and test method, the problem to be solved by the present application is to provide an experimental device and test method for testing the mechanical properties and leakage of a water supply pipeline joint, which can test the dynamic changes of the mechanical properties and leakage flow of the joint during tensioning, reflect the change characteristics of the joint leakage flow during the tensioning deformation of the pipeline structure, and reveal the relationship between the mechanical property parameters and the functional parameters of the pipeline joint, thereby laying a model foundation for the seismic function evaluation of the water supply pipeline network.

[0009] An experimental device for testing the mechanical properties and leakage of a water supply pipeline joint includes a test pipeline, a pipe end fixing device, a water pressure loading device, a pipeline deformation testing device, and a water flow information testing device. The test pipeline is fixed on the tension testing machine and the fixed support through the pipe end fixing device. The water pressure loading device realizes the circulation and pressurization of the water flow in the pipeline. The pipeline deformation testing device measures the strain of the pipe body and the deformation of the joint during the process of the tension testing machine pulling open the pipeline joint. The water flow information testing device measures the amount of leakage during the deformation of the joint.

[0010] The pipe end fixing device is composed of two parts. One part is a first flange, a rib plate, and a steel plate welded together, with the first flange perpendicular to the rib plate and the rib plate perpendicular to the steel plate. The other part is a second flange and a short pipe welded vertically, with the two second flanges connected by bolts. The short pipe of the fixing device is connected to the pipe segment by bolts at one end, and the steel plate at the other end is fixed to the MTS testing machine and the fixed support, respectively. Each group has two pipe end fixing devices.

[0011] The water pressure loading device is composed of a valve, a water pipe, a water pump, and a water tank. The water pump pumps the water in the water tank to realize the circulation of the water flow in the pipeline and maintain a certain water pressure. At the same time, a valve is set between the water pump and the pipe segment to facilitate the control of the water flow.

[0012] The pipeline deformation testing device is composed of a tension wire displacement meter and a strain gauge. The tension wire displacement meter is fixed at both ends of the pipeline joint to measure the deformation of the pipeline joint. The strain gauge is arranged along the pipe body to test the deformation of the pipe body during the experiment.

[0013] The water flow information testing device consists of a water pressure sensor, a water pressure gauge, a measuring cup, a mass scale, a stopwatch, a flow meter, and an acrylic glass box. The water pressure sensor is placed inside the pipe joint to test the change in water pressure during leakage. The water pressure gauge is placed at both ends of the pipe (inlet and outlet) to measure and record the water pressure values. The measuring cup collects the volume of water dripping from the joint and places it on the mass scale for data calibration. A water tank, filled with water, is placed on the mass scale to measure the change in water mass during the experiment. The stopwatch records the data at regular intervals, such as 10, 20, and 30 seconds, for each sensor and testing instrument. The flow meter measures the inflow and outflow from the water tank; the difference between the two values ​​can be used to estimate and verify the leakage flow rate. The acrylic glass box effectively collects the leaking water from the joint and directs it into the measuring cup.

[0014] The transparent acrylic box consists of two symmetrical parts that, when combined, completely enclose the tubing connector. The front and back sides of the box have cylindrical structures with inner diameters matching the tubing's outer diameter, connected to the side panels to fit over the tubing. Steel wire is then wrapped around the outside to secure it firmly. The bottom of the box features a funnel-shaped structure with a small circular hole at its lowest point to guide any leaking water into a measuring cup. This acrylic box effectively collects leaking water, reducing the risk of collection failure due to sudden water jets and thus minimizing experimental error.

[0015] The testing methods for the experimental setup include:

[0016] (1) After the experimental setup except for the acrylic box is installed and debugged, ensure that there is no water leakage and that all testing instruments are working properly. Finally, install the acrylic box and fix it on the connector, ensuring that the acrylic box is in close contact with the two pipe sections.

[0017] (2) Zero all testing instruments, start the MTS testing machine and begin timing, pull the pipe section to start moving, and record the force value F measured on the testing machine every 10 seconds. T Simultaneously, the values ​​from other sensors are recorded. This primarily includes the readings D from the wire displacement gauge. T The readings ε of the two strain gauges T1 and ε T2 The water pressure sensor reading is H. T The stopwatch reading is t, and the measuring cup reading is L. T The readings of the mass scale and the mass scale are respectively m T1 and m T2 The readings of the two flow meters are Q T1 and Q T2 The readings of the water pressure gauges are respectively H T1and H T2 .

[0018] (3) Verification between multiple test data, mainly including:

[0019] ① Verification of tensile data, including the calculation formulas for the axial tensile forces of the two pipe sections after strain occurs in the pipe body:

[0020] F1 = E P ε T1 (1)

[0021] F2 = E P ε T2 (2)

[0022] Where F1 and F2 are the axial forces of the two pipe sections, E P It is the elastic modulus of the pipe section / material. (This is achieved through F...) T The comparison of F1 and F2 can verify the accuracy of the test data and at the same time realize the test of the deformation of the pipe section during the pulling process.

[0023] ② Verification of leakage volume: This involves converting the mass of the leakage volume into volume and comparing it with the volume of the leakage measured by a measuring cup. The conversion formula is as follows:

[0024]

[0025] L1 is the volume of leaked water calculated based on the mass of water measured by the mass scale below the measuring cup.

[0026] Meanwhile, the volume of leaked water can also be obtained from the reading on the mass scale below the water tank, calculated using the following formula:

[0027]

[0028] Where L2 is the volume of leaked water calculated from the mass of water measured by the mass scale under the measuring cup, in meters. T2-0 and m T2-t These are the initial readings at the start of the experiment using the mass scale in the water tank and the reading at time t, respectively.

[0029] In addition, the volume of the leaked water can be calculated based on the difference between the readings of the two flow meters, using the following formula:

[0030] L3=(Q T1 -Q T2 )t (5)

[0031] Where L3 is the volume of leaked water calculated based on the difference in flow meter readings, and t is the stopwatch time.

[0032] By comparing LT L1, L2, and L3 can be used to verify the amount of water leakage.

[0033] ③ For the verification of water pressure at the leakage point, the water pressure at the leakage point can be directly determined based on the value H collected by the water pressure sensor. T Confirmed, in addition, the readings of the two water pressure gauges can be used to determine H. T1 and H T2 The calculation determines the formula as follows:

[0034]

[0035] H1 is the calculated water pressure at the joint leakage point.

[0036] By comparing H T H1 can be used to verify the water pressure at the leakage point.

[0037] The aforementioned data verification work can effectively reduce the error of the test data. On the other hand, it can also provide a backup source of calculation data when some of the sensors fail to work due to accidents, thereby improving the accuracy of the experiment.

[0038] (3) Draw the tension F of the tension joint. T Deformation of the joint D T The relationship curve. Abstracting the joint as a mechanical model composed of a tension spring, the stiffness of the axial tension spring is calculated based on the slope of the curve. The calculation formula is:

[0039]

[0040] Where k T It is the calculated stiffness of the axial spring of the joint, where d represents the differential calculation.

[0041] (4) The calculation formula for the joint leakage coefficient is as follows:

[0042]

[0043] Among them l k π is the joint leakage coefficient, π is pi, and g is the gravitational acceleration constant.

[0044] Based on the joint leakage coefficient at different times l k Deformation of pipeline joints D T By determining the relationship between the two, a curve showing their relationship is plotted to obtain the relationship between the joint leakage rate and joint deformation. The calculation formula is as follows:

[0045]

[0046] Among them, l T It is the rate of change of the joint leakage coefficient.

[0047] (6) Adjust the axial spring coefficient k of the pipeline T Leakage coefficient of pipeline joint l T The relationship is plotted in the figure to establish the mechanical performance parameter k of the pipeline joint. T Leakage coefficient of pipeline joint l k The relationship between the mechanical performance parameters of pipeline joints and their functional parameters was analyzed.

[0048] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0049] (1) This invention has the characteristics of clear principle, simple installation and operation. Through the MTS test machine and the rod displacement gauge at the pipeline joint, the relationship between the tension of the MTS test machine and the displacement of the pipeline joint can be easily obtained, thus providing an effective basis for determining the stiffness of the pipeline joint.

[0050] (2) This invention can also effectively observe the characteristics and conditions of pipeline water leakage as pipeline joints are subjected to tensile deformation. At the same time, based on the measured leakage amount and the relationship between the water pressure at the joint, the relationship between the leakage flow rate, water pressure and joint deformation at the pipeline joint is established, thereby establishing a leakage model of the pipeline joint and revealing the variation law of the leakage coefficient of the pipeline joint.

[0051] (3) This invention can effectively measure the dynamic changes of joint stiffness and leakage flow, reveal the relationship between the mechanical performance parameters and functional parameters of pipeline joints, clarify the leakage mechanism of pipeline joints, and provide a calculation basis for the functional evaluation of pipeline network under seismic action.

[0052] (4) At the same time, the experimental setup has excellent compatibility and can be used to measure pipelines with different diameters, materials, or joint types, thereby reducing the experimental testing costs for the characteristics of different types of water supply pipeline joints. In addition, the arrangement and testing methods of multiple sensors can effectively verify the data, reduce the testing error of the experimental data, and improve the accuracy of the experiment. Attached Figure Description

[0053] To more clearly illustrate the design details of this invention, the accompanying drawings required in the description are briefly introduced below. The drawings are merely embodiments of this invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0054] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0055] Figure 2 This is a three-dimensional schematic diagram of the plexiglass box in an embodiment of the present invention.

[0056] Figure 3 These are the front view, right view, and top view of the plexiglass box in an embodiment of the present invention.

[0057] Figure 4 This is a schematic diagram showing the relationship between the tensile force of the joint and the deformation of the joint in an embodiment of the present invention.

[0058] Figure 5 This is a schematic diagram showing the relationship between the joint leakage coefficient and the pipeline joint deformation in an embodiment of the present invention.

[0059] Figure 6 This is a schematic diagram showing the relationship between the mechanical performance parameters of the joint and the leakage coefficient of the pipeline joint in an embodiment of the present invention. Detailed Implementation

[0060] The present invention will be further explained below with reference to the embodiments and accompanying drawings, but this is not intended to limit the scope of protection of this application.

[0061] Example 1: This invention proposes an experimental apparatus and method for testing the mechanical properties and leakage of water supply pipeline joints. For example... Figure 1 As shown, the experimental setup comprises five parts: a test pipeline, a pipe end fixing device, a water pressure loading device, a pipeline deformation testing device, and a water flow information testing device. The test pipeline is fixed to the tensile testing machine and a support frame via the pipe end fixing device. The water pressure loading device circulates and pressurizes the water flow within the pipeline. The pipeline deformation testing device measures the strain of the pipe body and the deformation of the joint during the tensile testing machine's opening of the pipe joint. The water flow information testing device measures the amount of water leaking during the joint deformation process.

[0062] Test pipeline such as Figure 1 As shown, it includes a first pipe section 1 and a second pipe section 2, which are connected by a pipe joint 3.

[0063] The pipe end fixing device consists of two parts. One part is welded together from a first flange 4, a rib plate 5, and a steel plate 6, with the first flange 4 perpendicular to the rib plate 5 and the rib plate 5 perpendicular to the steel plate 6. The other part is a second flange 7 welded perpendicularly to a short pipe 8. The two flange parts are connected by bolts 9. One end of the short pipe is connected to pipe section 1 by bolts 10, and the other end of the steel plate 6 is fixed to the MTS testing machine 22 and the fixing bracket 23. Each group has two pipe end fixing devices.

[0064] The water pressure loading device consists of a valve 11, a water pipe 12, a water pump 13, and a water tank 14. The water pump 13 pumps the water in the water tank 14 to circulate the water in the pipeline and maintain a certain water pressure. At the same time, a valve 11 is installed between the water pump 13 and the second pipe section 2 to facilitate the control of the water flow.

[0065] The pipeline deformation testing device consists of a wire-type displacement gauge 15, a first strain gauge 16, and a second strain gauge 17. The two ends of the wire-type displacement gauge 15 are fixed to both sides of the pipeline joint 3 to measure the deformation of the pipeline joint. The first strain gauge 16 and the second strain gauge 17 are arranged circumferentially along the pipeline to test the deformation of the pipe body during the experiment.

[0066] The water flow information testing device consists of a water pressure sensor 18, a first water pressure gauge 26 and a second water pressure gauge 27, a measuring cup 19, a first mass scale 20 and a second mass scale 21, a stopwatch 29, a first flow meter 24 and a second flow meter 25, and an acrylic box 28. The water pressure sensor 18 is placed inside the pipe joint to test the change in water pressure during leakage. The first water pressure gauge 26 and the second water pressure gauge 27 are placed at the inlet and outlet pipes of the pipe, respectively, to test and record the water pressure values. The measuring cup 19 is used to collect the volume of water dripping from the joint and is placed on the first mass scale 20. After the water tank is filled with water, it is placed on the second mass scale 21 to measure the change in water mass during the experiment. The stopwatch 29 is a timing device that records the data of each sensor and testing instrument at regular intervals, such as 10, 20, and 30 seconds. The first flow meter 24 and the second flow meter 25 can test the inflow and outflow flow rates of the water tank; by comparing the difference between the two, the leakage flow rate can be estimated and verified. The plexiglass box 28 can effectively collect water leakage from the joint and guide it into the measuring cup 19.

[0067] The acrylic box is transparent, and its three-dimensional structure diagram is shown below. Figure 2 As shown, its front view, right view, and top view are respectively as follows: Figure 3 As shown, the box comprises a symmetrical first part, box B1, and a second part, box B2. B1 and B2 are combined to completely enclose the connector 2 of the pipeline. On both sides of the box are cylindrical structures B4, whose inner diameter is the same as the outer diameter of the pipeline, and which are connected to the side panel B3, allowing them to fit over the pipeline. Steel wire is wrapped around B4 to secure it firmly to the pipeline. The lower part of the box has a funnel-shaped structure B5, with a small circular hole B6 at the top of B5 to guide water leaking from the connector into a measuring cup 19. The glass box effectively collects leaking water from the connector, reducing collection failures caused by sudden water jets and thus minimizing experimental errors.

[0068] The testing method is as follows:

[0069] (1) After the experimental setup except for the acrylic box 28 is installed and debugged, ensure that there is no water leakage and that all testing instruments are working properly. Finally, install the acrylic box 28 and fix it on the connector 3 to ensure that the acrylic box 28 is in close contact with the first pipe section 1 and the second pipe section 2.

[0070] (2) Zero all testing instruments, start the MTS testing machine 22 and begin timing, pull the first pipe section 1 to start moving, and record the force value F measured on the testing machine every 10 seconds. T Simultaneously, the values ​​from other sensors are recorded. This primarily includes the reading D from the wire displacement gauge 15. T The readings ε of the first strain gauge 16 and the second strain gauge 17 T1 and ε T2 The value of water pressure sensor 18 is H. T The stopwatch reading is t, and the measuring cup 19 reading is L. T The readings of the first mass scale 20 and the second mass scale 21 are respectively m T1 and m T2 The readings of the first flow meter 24 and the second flow meter 25 are Q, respectively. T1 and Q T2 The readings of the first water pressure gauge 26 and the second water pressure gauge 27 are respectively H T1 and H T2 .

[0071] (3) Verification between multiple test data, mainly including:

[0072] ① Verification of tensile data, where the calculation formulas for the axial tensile forces of pipe section 1 and pipe section 2 after strain occurs in the pipe body are as follows:

[0073] F1 = E P ε T1 (1)

[0074] F2 = E P ε T2 (2)

[0075] Where F1 and F2 are the axial forces of pipe segment 1 and pipe segment 2, respectively, and E P It is the elastic modulus of the pipe section / material. (This is achieved through F...) T The comparison of F1 and F2 can verify the accuracy of the test data and at the same time realize the test of the deformation of the pipe section during the pulling process.

[0076] ② Verification of leakage volume: The mass of the leakage volume is converted into volume and compared with the volume of leakage measured by measuring cup 19. The conversion formula is as follows:

[0077]

[0078] L1 is the volume of the leaking water calculated based on the mass of water measured by the first mass scale 20.

[0079] Meanwhile, the volume of the leaking water can also be obtained based on the reading of the second mass scale 21, calculated using the following formula:

[0080]

[0081] Where L2 is the volume of the leaked water calculated from the mass of water measured by the mass scale 21, in m T2-0 and m T2-t These are the initial readings at the start of the second mass scale experiment and the readings at time t, respectively.

[0082] In addition, the volume of the leaked water can also be calculated based on the difference between the readings of the first flow meter 24 and the second flow meter 25, using the following formula:

[0083] L3=(Q T1 -Q T2 )t (5)

[0084] Where L3 is the volume of leaked water calculated based on the difference in flow meter readings, and t is the stopwatch time.

[0085] By comparing L T L1, L2, and L3 can be used to verify the amount of water leakage.

[0086] ③ For the verification of water pressure at the leakage point, the water pressure at the leakage point can be directly determined based on the value H collected by the water pressure sensor 18. T Furthermore, the readings of the first water pressure gauge 26 and the second water pressure gauge 27 can be used to determine H. T1 and H T2 The calculation determines the formula as follows:

[0087]

[0088] H1 is the calculated water pressure at the joint leakage point.

[0089] By comparing H T H1 can be used to verify the water pressure at the leakage point.

[0090] The aforementioned data verification work can effectively reduce the error of the test data. On the other hand, it can also provide a backup source of calculation data when some of the sensors fail to work due to accidents, thereby improving the accuracy of the experiment.

[0091] (3) Draw the tension F of the tension joint. T Deformation of the joint D T The relationship curve, and its possible schematic diagram are as follows: Figure 4 As shown.

[0092] The joint is abstracted as a mechanical model composed of a tension spring. Based on the slope of the curve, the stiffness of the axial tension spring is calculated using the following formula:

[0093]

[0094] Where k T It is the calculated stiffness of the axial spring of the joint, where d represents the differential calculation.

[0095] (4) The calculation formula for the joint leakage coefficient is as follows:

[0096]

[0097] Among them l k π is the joint leakage coefficient, π is pi, and g is the gravitational acceleration constant.

[0098] Based on the joint leakage coefficient at different times l k Deformation of pipeline joints D T To illustrate the relationship between the two, draw a relationship curve. A possible relationship diagram is shown below. Figure 5 As shown, the relationship between the joint leakage rate and joint deformation is obtained, and the calculation formula is as follows:

[0099]

[0100] Among them, l T It is the rate of change of the joint leakage coefficient.

[0101] (6) Adjust the axial spring coefficient k of the pipeline T Leakage coefficient of pipeline joint l T The relationship is plotted in the figure to establish the mechanical performance parameter k of the pipeline joint. T Leakage coefficient of pipeline joint l k The relationship between pipeline joint mechanical performance parameters and their functional parameters is analyzed. A possible schematic diagram of the relationship is shown below. Figure 6 As shown.

[0102] The above description of specific embodiments is provided to facilitate understanding and application by those skilled in the art. Those familiar with the art can easily modify the above process and apply this principle to other examples without repeating creative work. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made to the present invention by those skilled in the art based on the disclosure thereof should be within the scope of protection of the present invention.

Claims

1. An experimental apparatus for testing the mechanical properties and leakage of water supply pipeline joints, comprising five parts: a test pipeline, a pipe end fixing device, a water pressure loading device, a pipeline deformation testing device, and a water flow information testing device; characterized in that: The test pipeline is fixed to the tensile testing machine and the fixed bracket by the pipe end fixing device; the water pressure loading device realizes the circulation and pressurization of water flow in the pipeline; the pipeline deformation testing device measures the strain of the pipe body and the deformation of the joint during the tensile test machine pulling open the pipeline joint; the water flow information testing device measures the amount of water leakage during the joint deformation process. The test pipeline includes a first pipe section (1) and a second pipe section (2), and the pipe sections are connected by a connector (3); The pipe end fixing device consists of two parts. One part is a first flange (4), a rib (5), and a steel plate (6) welded together. The first flange (4) is perpendicular to the rib (5), and the rib (5) is perpendicular to the steel plate (6). The other part is a second flange (7) and a short pipe (8) welded together. The two flanges are connected by a first bolt (9). One end of the short pipe of the fixing device is connected to the first pipe section (1) by a second bolt (10). The steel plate (6) connected to the rib is fixed on the MTS testing machine (22) and the fixing bracket (23) respectively. Each group has two pipe end fixing devices, and the two fixing devices are designed symmetrically. The water pressure loading device consists of a valve (11), a water pipe (12), a water pump (13), and a water tank (14). The water pump (13) pumps the water in the water tank (14) to circulate the water in the pipeline and maintain a certain water pressure. At the same time, a valve (11) is set between the water pump (13) and the second pipe section (2) to facilitate the control of the water flow. The pipeline deformation testing device consists of a pull-wire displacement gauge (15), a first strain gauge (16), and a second strain gauge (17). The two ends of the pull-wire displacement gauge (15) are fixed to both sides of the pipeline joint (3) to measure the deformation of the pipeline joint. The first strain gauge (16) and the second strain gauge (17) are arranged circumferentially along the pipeline to test the deformation of the pipe body during the experiment. The water flow information testing device consists of a water pressure sensor (18), a first water pressure gauge (26), a second water pressure gauge (27), a measuring cup (19), a first mass scale (20), a second mass scale (21), a stopwatch (29), a first flow meter (24), a second flow meter (25), and an acrylic box (28). The water pressure sensor (18) is placed inside the pipe joint to test the change in water pressure at the joint during leakage. The first water pressure gauge (26) and the second water pressure gauge (27) are placed at the outlet and inlet pipes at both ends of the pipe to test and record the water pressure values. The measuring cup (19) is used to collect water pressure data from the joint. The volume of the leaking water is measured and placed on the first mass scale (20) for data verification; after the water tank is filled with water, it is placed on the second mass scale (21) to measure the change in water mass during the experiment; the stopwatch (29) is a timing device that records the readings of the second water pressure gauge (27) and the first mass scale (20) at regular intervals; the first flow meter (24) and the second flow meter (25) measure the flow rate in and out of the water tank, and the leakage flow rate can be estimated by comparing the difference between the two; the plexiglass box (28) collects the water leaking from the joint and guides it into the measuring cup (19).

2. The experimental apparatus for testing the mechanical properties and leakage of water supply pipeline joints as described in claim 1, characterized in that: The plexiglass box is transparent and consists of two symmetrical parts, namely the first part (B1) and the second part (B2). The first part (B1) and the second part (B2) are combined to completely enclose the connector (3) of the pipeline. There are cylindrical structures (B4) on the front and back sides of the box. The inner diameter of the structure is the same as the outer diameter of the pipeline and is connected to the side panel (B3) to fit on the pipeline. The cylindrical structure (B4) is wrapped with steel wire to firmly fix it to the pipeline. The bottom of the box is a funnel-shaped structure (B5). At the bottom of the funnel-shaped structure (B5) is a small circular hole (B6) to guide the water leaking from the connector into the measuring cup (19).

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