A mechanical strength testing tool for HDPE corrugated pipe

Abstract

The present application provides a mechanical strength test tool for HDPE corrugated pipes, including a first push assembly and a second push assembly, a clamping channel is formed between the first push assembly and the second push assembly, the first push assembly and the second push assembly can be extended and retracted, and the width and curvature of the clamping channel are changed after the first push assembly and the second push assembly are extended and retracted to imitate the shape of a trench, the clamping channel is used to clamp the HDPE corrugated pipe, and a displacement sensor and a pressure sensor are installed on the first push assembly and the second push assembly, the displacement sensor is used to detect the extension amount of the first push assembly and the second push assembly, and the pressure sensor is used to detect the pressure between the first push assembly and the HDPE corrugated pipe and between the second push assembly and the HDPE corrugated pipe. The control variable method is adopted to control the pressure to be constant to analyze and calculate the displacement data, and then the pressure data is calculated and analyzed by controlling the displacement to be constant, so as to accurately obtain the mechanical strength law of the HDPE corrugated pipe when it is bent.

Description

Technical Field

[0001] The present application relates to the technical field of corrugated pipe strength testing, and in particular to a HDPE corrugated pipe mechanical strength testing tool. Background Art

[0002] HDPE corrugated pipe is also called PE corrugated pipe, which is a plastic protective sleeve extruded from polyethylene. It is also called corrugated pipe because of its annular corrugation inside and outside. It protects cables from damage. It has good wear resistance and corrosion resistance. Because PE material is more resistant to corrosion, wear and aging, and is green and environmentally friendly, PE corrugated pipe is also often used as a rainwater and sewage branch pipe.

[0003] When the HDPE corrugated pipe is laid in a curved trench, the outer wall of the HDPE corrugated pipe abuts against the inner wall of the trench, and the inner wall of the trench presses against the HDPE corrugated pipe, causing it to bend along with the trench. As the degree of bending changes, the amount of extrusion deformation of the outer wall of the HDPE corrugated pipe (the depth of the depression toward the inside of the HDPE corrugated pipe) also varies. Generally, the greater the degree of bending, the greater the extrusion deformation. In the production process of HDPE corrugated pipes, it is necessary to test the mechanical strength of HDPE corrugated pipes to obtain the corresponding extrusion deformation of the HDPE corrugated pipes under various preset bending degrees. In the prior art, one end of the HDPE corrugated pipe is usually fixed, and then a push rod is used to press the other end of the HDPE corrugated pipe to cause the HDPE corrugated pipe to bend and deform. However, this bending deformation does not match the bending shape of the trench. The bending shape of the trench is usually an arc. However, the bending shape of one end of the HDPE corrugated pipe is close to a parabola, which is quite different from the actual working conditions. The reliability of the test results is low. Therefore, it is necessary to design a HDPE corrugated pipe mechanical strength test tool to test and obtain the law of the corresponding extrusion deformation of the HDPE corrugated pipe when it is bent in an arc. Summary of the invention

[0004] The present application provides a HDPE corrugated pipe mechanical strength testing tool, which is used to solve the problem in the prior art that the bending shape of one end of the HDPE corrugated pipe is close to a parabola, which is greatly different from the actual working conditions and the reliability of the test results is low.

[0005] In order to achieve the above objectives, the embodiments of the present application propose the following technical solutions:

[0006] A tool for testing the mechanical strength of an HDPE corrugated pipe comprises a first pushing assembly and a second pushing assembly, wherein the first pushing assembly comprises a plurality of first hydraulic cylinders, the first hydraulic cylinders are arranged side by side, the first hydraulic cylinders are arranged on the same plane, and the piston rods of the first hydraulic cylinders face the same direction; the second pushing assembly comprises a plurality of second hydraulic cylinders, the second hydraulic cylinders are arranged side by side, the second hydraulic cylinders are arranged on the same plane, and the piston rods of the second hydraulic cylinders face the same direction; the arrangement plane where the first hydraulic cylinders are located is located on the same plane as the arrangement plane where the second hydraulic cylinders are located, the central axis of the first hydraulic cylinder is located on the same straight line as the central axis of the second hydraulic cylinder, the piston rod of the first hydraulic cylinder faces the piston rod close to the second hydraulic cylinder, and the piston rod of the second hydraulic cylinder faces the piston rod close to the first hydraulic cylinder, and the direction of the piston rod of the first hydraulic cylinder is opposite to that of the piston rod of the second hydraulic cylinder; a clamping channel is formed between the ends of the piston rods of the first hydraulic cylinder and the piston rods of the second hydraulic cylinder that are close to each other;

[0007] The HDPE corrugated pipe mechanical strength testing tool further includes a first displacement sensor and a first pressure sensor, wherein the first displacement sensor is used to detect the distance of extension and retraction of the piston rod of the first hydraulic cylinder, and the first pressure sensor is used to detect the pressure exerted on the piston rod of the first hydraulic cylinder in a direction parallel to the first hydraulic cylinder;

[0008] The HDPE corrugated pipe mechanical strength testing tool also includes a second displacement sensor and a second pressure sensor, the second displacement sensor is used to detect the extension and retraction distance of the piston rod of the second hydraulic cylinder, and the second pressure sensor is used to detect the pressure exerted on the piston rod of the second hydraulic cylinder in a direction parallel to the second hydraulic cylinder.

[0009] In some embodiments, the arrangement spacing of the first hydraulic cylinders is uniform.

[0010] In some embodiments, the distance between the center axes of adjacent first hydraulic cylinders is less than or equal to 50 mm.

[0011] In some embodiments, a first push rod is fixedly connected to the end surface of the piston rod of the first hydraulic cylinder close to the second hydraulic cylinder. The first push rod is cylindrical in shape, and the center axis of the first push rod is perpendicular to the arrangement plane where the first hydraulic cylinders are located.

[0012] In some embodiments, the first pressure sensor is located between the first push rod and the end surface of the piston rod of the first hydraulic cylinder, one side of the first pressure sensor is fixedly connected to the first push rod, and the other side of the first pressure sensor is fixedly connected to the end surface of the piston rod of the first hydraulic cylinder.

[0013] In some embodiments, the HDPE corrugated pipe mechanical strength testing tool also includes a first fixed frame, the cylinder body of the first hydraulic cylinder is fixedly connected to the first fixed frame, the first displacement sensor is fixedly connected to the first fixed frame, the first displacement sensor is an infrared distance sensor, and the infrared emitting end of the first displacement sensor is facing the first push rod in a direction parallel to the first hydraulic cylinder.

[0014] In some embodiments, a second push rod is fixedly connected to the end surface of the piston rod of the second hydraulic cylinder close to the first hydraulic cylinder. The second push rod is cylindrical in shape, and the center axis of the second push rod is perpendicular to the arrangement plane where the second hydraulic cylinders are located.

[0015] In some embodiments, the second pressure sensor is located between the second push rod and the end surface of the piston rod of the second hydraulic cylinder, one side of the second pressure sensor is fixedly connected to the second push rod, and the other side of the second pressure sensor is fixedly connected to the end surface of the piston rod of the second hydraulic cylinder.

[0016] In some embodiments, the HDPE corrugated pipe mechanical strength testing tool also includes a second fixed frame, the cylinder body of the second hydraulic cylinder is fixedly connected to the second fixed frame, the second displacement sensor is fixedly connected to the second fixed frame, the second displacement sensor is an infrared distance sensor, and the infrared emitting end of the second displacement sensor is facing the second push rod in a direction parallel to the second hydraulic cylinder.

[0017] In some embodiments, the HDPE corrugated pipe mechanical strength testing tool also includes a workbench, the upper surface of the workbench is horizontally arranged, the arrangement plane where the first hydraulic cylinder is located is parallel to the upper surface of the workbench, the first hydraulic cylinder and the second hydraulic cylinder are located above the workbench, the cylinder body of the first hydraulic cylinder is fixedly connected to the workbench, and the cylinder body of the second hydraulic cylinder is fixedly connected to the workbench; a positioning plate is provided at one end of the clamping channel, the positioning plate is located above the workbench, the positioning plate is fixedly connected to the upper surface of the workbench, and the positioning plate is perpendicular to the upper surface of the workbench. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the HDPE corrugated pipe mechanical strength testing tool in the embodiment of the present application;

[0019] Figure 2 yes Figure 1 A-direction view;

[0020] Figure 3 yes Figure 1 A partial enlarged view of point B in the middle;

[0021] Figure 4 yes Figure 1 A partial enlarged view of point C in the middle;

[0022] Figure 5 It is a structural schematic diagram of the HDPE corrugated pipe mechanical strength test tooling clamped in the clamping channel in the embodiment of the present application;

[0023] Figure 6 It is a structural schematic diagram of the HDPE corrugated pipe mechanical strength test tool in the embodiment of the present application when the HDPE corrugated pipe is bent in one direction;

[0024] Figure 7 It is a structural schematic diagram of the HDPE corrugated pipe mechanical strength testing tool in the embodiment of the present application when the HDPE corrugated pipe is bent in another direction.

[0025] Reference numerals:

[0026] 101. First pushing assembly; 102. Second pushing assembly; 103. First hydraulic cylinder; 104. Second hydraulic cylinder; 105. Clamping channel; 106. First displacement sensor; 107. First pressure sensor; 108. Second displacement sensor; 109. Second pressure sensor; 110. First push rod; 111. First fixed frame; 112. Second push rod; 113. Second fixed frame; 114. Workbench; 115. Positioning plate; 116. HDPE corrugated pipe. DETAILED DESCRIPTION

[0027] The following is a further detailed description of the implementation of the present application in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application but cannot be used to limit the scope of the present application.

[0028] like Figure 1 , Figure 2 and Figure 5As shown, in an embodiment of the present application, a mechanical strength testing tool for a HDPE corrugated pipe 116 is provided, including a first pushing assembly 101 and a second pushing assembly 102, the first pushing assembly 101 including a plurality of first hydraulic cylinders 103, the first hydraulic cylinders 103 are arranged side by side, the first hydraulic cylinders 103 are arranged on the same plane, and the piston rods of the first hydraulic cylinders 103 are oriented in the same direction; the second pushing assembly 102 includes a plurality of second hydraulic cylinders 104, the second hydraulic cylinders 104 are arranged side by side, the second hydraulic cylinders 104 are arranged on the same plane, and the piston rods of the second hydraulic cylinders 104 are oriented in the same direction; the arrangement plane where the first hydraulic cylinders 103 are located and the arrangement plane where the second hydraulic cylinders 104 are located are located on the same plane, the central axis of the first hydraulic cylinder 103 and the central axis of the second hydraulic cylinder 104 are located on the same straight line, the piston rod of the first hydraulic cylinder 103 faces the piston rod close to the second hydraulic cylinder 104, and the piston rod of the second hydraulic cylinder 104 faces the piston rod close to the first hydraulic cylinder 103. The piston rod of the first hydraulic cylinder 103 is oriented in the opposite direction to the piston rod of the second hydraulic cylinder 104; a clamping channel 105 is formed between the ends of the piston rod of the first hydraulic cylinder 103 and the piston rod of the second hydraulic cylinder 104 that are close to each other; the HDPE corrugated pipe 116 mechanical strength testing tool also includes a first displacement sensor 106 and a first pressure sensor 107, the first displacement sensor 106 is used to detect the extension and retraction distance of the piston rod of the first hydraulic cylinder 103, and the first pressure sensor 107 is used to detect the pressure exerted on the piston rod of the first hydraulic cylinder 103 in a direction parallel to the first hydraulic cylinder 103; the HDPE corrugated pipe 116 mechanical strength testing tool also includes a second displacement sensor 108 and a second pressure sensor 109, the second displacement sensor 108 is used to detect the extension and retraction distance of the piston rod of the second hydraulic cylinder 104, and the second pressure sensor 109 is used to detect the pressure exerted on the piston rod of the second hydraulic cylinder 104 in a direction parallel to the second hydraulic cylinder 104.

[0029] like Figure 5 , Figure 6 and Figure 7As shown, the HDPE corrugated pipe 116 mechanical strength test tool provided in this embodiment, during the working process, the HDPE corrugated pipe 116 is placed in the clamping channel 105, and the first hydraulic cylinder 103 and the second hydraulic cylinder 104 are respectively extended until the ends of the piston rods are in contact with the HDPE corrugated pipe 116. At this time, the ends of the piston rods of the first hydraulic cylinder 103 are located in a straight line, and the ends of the piston rods of the second hydraulic cylinder 104 are located in a straight line, and the arrangement plane where the first hydraulic cylinder 103 is located passes through the central axis of the HDPE corrugated pipe 116, and the hydraulic control system is used to control the first hydraulic cylinder 103 and the second hydraulic cylinder 104 to be respectively in a straight line. 3 and the expansion and contraction of the second hydraulic cylinder 104, so that the clamping channel 105 is bent into a preset arc, and at the same time, the vertical distance between the inner circle and the outer circle of the clamping channel 105 is controlled to be equal to the outer wall diameter of the HDPE corrugated pipe 116. After a period of time, the data detected by the first displacement sensor 106, the second displacement sensor 108, the first pressure sensor 107 and the second pressure sensor 109 are collected by the computer, and the pressure values ​​and deformation corresponding to the inner side of the arc of the HDPE corrugated pipe 116 and the outer side of the arc of the HDPE corrugated pipe 116 and the top pressure points of each hydraulic cylinder are obtained by analyzing and calculating these data. The control variable method is adopted to control the pressure to be constant to analyze and calculate the displacement data, and then the pressure data is calculated and analyzed by controlling the displacement to accurately obtain the mechanical strength law of the HDPE corrugated pipe 116 when it is bent. By controlling the expansion and contraction of the first hydraulic cylinder 103 and the second hydraulic cylinder 104, the clamping channel 105 with various bending degrees can be obtained, so as to test the mechanical strength change law of the HDPE corrugated pipe 116 at different bending degrees.

[0030] The first hydraulic cylinder 103 and the second hydraulic cylinder 104 can work together to perform bidirectional bending detection on the HDPE corrugated pipe 116. When the first hydraulic cylinder 103 contracts and the second hydraulic cylinder 104 extends, the HDPE corrugated pipe 116 bends toward the first hydraulic cylinder 103; when the first hydraulic cylinder 103 extends and the second hydraulic cylinder 104 contracts, the HDPE corrugated pipe 116 bends toward the second hydraulic cylinder 104.

[0031] In some implementations, the arrangement intervals of the first hydraulic cylinders 103 are uniform.

[0032] In some implementations, the distance between the central axes of adjacent first hydraulic cylinders 103 is less than or equal to 50 mm.

[0033] Through the above implementation, the smaller the distance between the central axes of the first hydraulic cylinders 103, the denser the points where the first hydraulic cylinders 103 push the outer wall of the HDPE corrugated pipe 116, the larger the collected data samples, and the higher the detection accuracy.

[0034] like Figure 2 and Figure 3As shown, in some embodiments, a first push rod 110 is fixedly connected to the end surface of the piston rod of the first hydraulic cylinder 103 close to the second hydraulic cylinder 104. The first push rod 110 is cylindrical in shape, and the central axis of the first push rod 110 is perpendicular to the arrangement plane where the first hydraulic cylinder 103 is located.

[0035] Through the above-mentioned embodiment, the HDPE corrugated pipe 116 will be deformed to a certain extent when being pressed and its axis may deviate from the arrangement plane where the first hydraulic cylinder 103 is located within a certain range. The first push rod 110 is set to be cylindrical and perpendicular to the arrangement plane where the first hydraulic cylinder 103 is located, so that the HDPE corrugated pipe 116 will not slip off the first push rod 110.

[0036] like Figure 3 As shown, in some embodiments, the first pressure sensor 107 is located between the first push rod 110 and the end surface of the piston rod of the first hydraulic cylinder 103, one side of the first pressure sensor 107 is fixedly connected to the first push rod 110, and the other side of the first pressure sensor 107 is fixedly connected to the end surface of the piston rod of the first hydraulic cylinder 103.

[0037] Through the above implementation, the first pressure sensor 107 uses a piezoresistive sheet, which can detect the axial (direction parallel to the central axis of the first hydraulic cylinder 103) compressive stress exerted on the piston rod of the first hydraulic cylinder 103, thereby obtaining the pressure exerted on the HDPE corrugated pipe 116 at the corresponding point.

[0038] like Figure 1 and Figure 2 As shown, in some embodiments, the mechanical strength testing tool for the HDPE corrugated pipe 116 also includes a first fixed frame 111, the cylinder body of the first hydraulic cylinder 103 is fixedly connected to the first fixed frame 111, the first displacement sensor 106 is fixedly connected to the first fixed frame 111, the first displacement sensor 106 is an infrared distance sensor, and the infrared emitting end of the first displacement sensor 106 is facing the first push rod 110 in a direction parallel to the first hydraulic cylinder 103.

[0039] Through the above implementation, the first displacement sensor 106 detects the distance between itself and the first push rod 110 through infrared rays. After the first hydraulic cylinder 103 is extended or retracted, the first infrared sensor transmits the changed inspection data to the computer for analysis and calculation.

[0040] In some embodiments, a second push rod 112 is fixedly connected to the end surface of the piston rod of the second hydraulic cylinder 104 close to the first hydraulic cylinder 103. The second push rod 112 is cylindrical in shape, and the central axis of the second push rod 112 is perpendicular to the arrangement plane where the second hydraulic cylinder 104 is located.

[0041] Through the above-mentioned embodiment, the HDPE corrugated pipe 116 will be deformed to a certain extent when being pressed and its axis may deviate from the arrangement plane where the second hydraulic cylinder 104 is located within a certain range. The second push rod 112 is set to be cylindrical and perpendicular to the arrangement plane where the second hydraulic cylinder 104 is located, so that the HDPE corrugated pipe 116 will not slip off the second push rod 112.

[0042] like Figure 4 As shown, in some embodiments, the second pressure sensor 109 is located between the second push rod 112 and the end face of the piston rod of the second hydraulic cylinder 104, one side of the second pressure sensor 109 is fixedly connected to the second push rod 112, and the other side of the second pressure sensor 109 is fixedly connected to the end face of the piston rod of the second hydraulic cylinder 104.

[0043] Through the above implementation, the second pressure sensor 109 uses a piezoresistive sheet, which can detect the axial (direction parallel to the central axis of the second hydraulic cylinder 104) compressive stress exerted on the piston rod of the second hydraulic cylinder 104, thereby obtaining the pressure exerted on the HDPE corrugated pipe 116 at the corresponding point.

[0044] like Figure 1 and Figure 2 As shown, in some embodiments, the mechanical strength testing tool for the HDPE corrugated pipe 116 also includes a second fixed frame 113, the cylinder body of the second hydraulic cylinder 104 is fixedly connected to the second fixed frame 113, the second displacement sensor 108 is fixedly connected to the second fixed frame 113, the second displacement sensor 108 is an infrared distance sensor, and the infrared emitting end of the second displacement sensor 108 is facing the second push rod 112 in a direction parallel to the second hydraulic cylinder 104.

[0045] Through the above implementation, the second displacement sensor 108 detects the distance between itself and the second push rod 112 through infrared rays. After the second hydraulic cylinder 104 is extended or retracted, the second infrared sensor transmits the changed inspection data to the computer for analysis and calculation.

[0046] In some embodiments, the mechanical strength testing tool for the HDPE corrugated pipe 116 also includes a workbench 114, the upper surface of the workbench 114 is horizontally arranged, the arrangement plane where the first hydraulic cylinder 103 is located is parallel to the upper surface of the workbench 114, the first hydraulic cylinder 103 and the second hydraulic cylinder 104 are located above the workbench 114, the cylinder body of the first hydraulic cylinder 103 is fixedly connected to the workbench 114, and the cylinder body of the second hydraulic cylinder 104 is fixedly connected to the workbench 114; a positioning plate 115 is provided at one end of the clamping channel 105, the positioning plate 115 is located above the workbench 114, the positioning plate 115 is fixedly connected to the upper surface of the workbench 114, and the positioning plate 115 is perpendicular to the upper surface of the workbench 114.

[0047] Through the above implementation, the workbench 114 can support the lower surface of the HDPE bellows 116. The HDPE bellows 116 is placed horizontally to reduce the interference of gravity on the detection results and improve the detection accuracy. Preferably, lubricating oil is applied to the upper surface of the workbench 114 to reduce the friction between the HDPE bellows 116 and the upper surface of the workbench 114, thereby reducing the interference of friction resistance on the detection results. The length of the HDPE bellows 116 is cut to a preset length. After the end of the HDPE bellows 116 abuts against the positioning plate 115, the center position of the arrangement length of the first hydraulic cylinder 103 can be aligned with the center position between the two ends of the HDPE bellows 116.

[0048] The above embodiments are merely explanations of the present application and are not limitations of the present application. After reading this specification, those skilled in the art may make modifications to the implementation methods of the present application as needed without any creative contribution. However, as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A HDPE corrugated pipe mechanical strength test tool, characterized in that: It comprises a first pushing assembly and a second pushing assembly, wherein the first pushing assembly comprises a plurality of first hydraulic cylinders, the first hydraulic cylinders are arranged side by side, the first hydraulic cylinders are arranged on the same plane, and the piston rods of the first hydraulic cylinders are oriented in the same direction; the second pushing assembly comprises a plurality of second hydraulic cylinders, the second hydraulic cylinders are arranged side by side, the second hydraulic cylinders are arranged on the same plane, and the piston rods of the second hydraulic cylinders are oriented in the same direction; the arrangement plane where the first hydraulic cylinders are located is located on the same plane as the arrangement plane where the second hydraulic cylinders are located, the central axis of the first hydraulic cylinder is located on the same straight line as the central axis of the second hydraulic cylinder, the piston rod of the first hydraulic cylinder is located on the piston rod close to the second hydraulic cylinder, and the piston rod of the second hydraulic cylinder is oriented in the opposite direction to the piston rod of the second hydraulic cylinder; a clamping channel is formed between the ends of the piston rods of the first hydraulic cylinder and the piston rods of the second hydraulic cylinder that are close to each other; The HDPE corrugated pipe mechanical strength testing tool further includes a first displacement sensor and a first pressure sensor, wherein the first displacement sensor is used to detect the distance of extension and retraction of the piston rod of the first hydraulic cylinder, and the first pressure sensor is used to detect the pressure exerted on the piston rod of the first hydraulic cylinder in a direction parallel to the first hydraulic cylinder; The HDPE corrugated pipe mechanical strength testing tool also includes a second displacement sensor and a second pressure sensor, wherein the second displacement sensor is used to detect the extension distance of the piston rod of the second hydraulic cylinder, and the second pressure sensor is used to detect the pressure exerted on the piston rod of the second hydraulic cylinder in a direction parallel to the second hydraulic cylinder. The HDPE corrugated pipe mechanical strength testing tool also includes a workbench, the upper surface of the workbench is horizontally arranged, the arrangement plane where the first hydraulic cylinder is located is parallel to the upper surface of the workbench, the first hydraulic cylinder and the second hydraulic cylinder are located above the workbench, the cylinder body of the first hydraulic cylinder is fixedly connected to the workbench, and the cylinder body of the second hydraulic cylinder is fixedly connected to the workbench; a positioning plate is provided at one end of the clamping channel, the positioning plate is located above the workbench, the positioning plate is fixedly connected to the upper surface of the workbench, and the positioning plate is perpendicular to the upper surface of the workbench; the upper surface of the workbench is provided with lubricating oil; A first push rod is fixedly connected to the end surface of the piston rod of the first hydraulic cylinder close to the second hydraulic cylinder. The first push rod is cylindrical in shape, and the central axis of the first push rod is perpendicular to the arrangement plane where the first hydraulic cylinders are located; The first pressure sensor is located between the first push rod and the end surface of the piston rod of the first hydraulic cylinder, one surface of the first pressure sensor is fixedly connected to the first push rod, and the other surface of the first pressure sensor is fixedly connected to the end surface of the piston rod of the first hydraulic cylinder; A second push rod is fixedly connected to the end surface of the piston rod of the second hydraulic cylinder close to the first hydraulic cylinder. The second push rod is cylindrical in shape, and the central axis of the second push rod is perpendicular to the arrangement plane where the second hydraulic cylinder is located; The second pressure sensor is located between the second push rod and the end surface of the piston rod of the second hydraulic cylinder, one surface of the second pressure sensor is fixedly connected to the second push rod, and the other surface of the second pressure sensor is fixedly connected to the end surface of the piston rod of the second hydraulic cylinder.

2. The HDPE corrugated pipe mechanical strength testing tool according to claim 1, characterized in that: The arrangement spacing of the first hydraulic cylinders is uniform.

3. The HDPE corrugated pipe mechanical strength testing tool according to claim 2, characterized in that: The distance between the central axes of adjacent first hydraulic cylinders is less than or equal to 50 mm.

4. The HDPE corrugated pipe mechanical strength testing tool according to any one of claims 1 to 3, characterized in that: The HDPE corrugated pipe mechanical strength testing tool also includes a first fixed frame, the cylinder body of the first hydraulic cylinder is fixedly connected to the first fixed frame, the first displacement sensor is fixedly connected to the first fixed frame, the first displacement sensor is an infrared distance sensor, and the infrared emitting end of the first displacement sensor is facing the first push rod in a direction parallel to the first hydraulic cylinder.

5. The HDPE corrugated pipe mechanical strength testing tool according to any one of claims 1 to 3, characterized in that: The HDPE corrugated pipe mechanical strength testing tool also includes a second fixed frame, the cylinder body of the second hydraulic cylinder is fixedly connected to the second fixed frame, the second displacement sensor is fixedly connected to the second fixed frame, the second displacement sensor is an infrared distance sensor, and the infrared emitting end of the second displacement sensor is facing the second push rod in a direction parallel to the second hydraulic cylinder.

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