A transverse fatigue testing machine for self-anchored pipe joints

Abstract

The application discloses a kind of transverse fatigue testing machines of steel pipe self-anchored interface, belong to self-anchored pipe testing technical field, including frame and installation component, frame is the rectangular frame built by several steel frames, and the both ends of frame are respectively provided with test joint, two sections of self-anchored pipe are connected and other two sections are respectively self-anchored with two test joints, form three test points in series;Test joint is installed in frame by installation component, and installation component includes limiting rod and first monitoring unit, test joint is provided with installation through-hole, limiting rod is assembled with test joint by passing through installation through-hole, and first detection unit is arranged on the surface of limiting rod, for detecting the load of test joint, the construction of the application is constructed by three test points in series, the continuity of pipeline system is constructed Environment, so that the transmission and distribution of load between interfaces can be accurately measured.

Description

Technical Field

[0001] This invention belongs to the field of self-anchoring pipe testing technology, specifically relating to a transverse fatigue testing machine for self-anchoring interface steel pipes. Background Technology

[0002] Self-anchoring piping systems, with their advantages of self-anchoring interfaces, reliable sealing, and good seismic performance, have been widely used in critical engineering fields such as municipal water supply and drainage, and oil and gas transportation. Their core performance directly depends on the structural integrity and sealing of the pipe interfaces under complex service environments. Therefore, precise laboratory testing of self-anchoring pipe interfaces is a prerequisite for ensuring project safety.

[0003] Currently, the industry standard for interface performance testing primarily employs a single-interface testing mode. This mode anchors two pipe sections to strong, rigid clamps at both ends of the testing machine, forming a test interface between the two sections. During testing, actuators apply axial tensile, bending, or cyclic internal pressure loads to this interface to evaluate its performance. However, this traditional testing method has inherent and increasingly prominent limitations, making it difficult to accurately reflect the behavior of the piping system under actual operating conditions.

[0004] Real pipelines are continuous systems consisting of dozens or even hundreds of joints connected in series. When pipelines deform due to temperature changes, uneven foundation settlement, or external loads, the load is transferred and distributed between adjacent joints. Traditional single-joint testing isolates the joint under test, with the pipe sections at both ends rigidly anchored. This is equivalent to assuming that adjacent joints are infinitely rigid, ignoring the continuity effect of the pipeline system. As a result, the test results are too idealized and cannot assess the true stress state of the joint in the system's anchoring chain.

[0005] Therefore, a transverse fatigue testing machine for self-anchored steel pipes is needed. Summary of the Invention

[0006] To address the aforementioned problems in the existing technology, this invention provides a transverse fatigue testing machine for self-anchored steel pipes, which solves the problem that traditional single-interface testing isolates the interface to be tested, making it impossible to assess the true stress state of the interface in the system's anchoring chain.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A transverse vibration testing machine for a fully self-anchored steel pipe includes a frame and an installation assembly. The frame is a rectangular frame constructed from several steel frames. Test joints are provided at both ends of the frame. Two sections of the self-anchored pipe are connected, and the other two sections are self-anchored to two test joints respectively, forming three test points in series.

[0009] The test connector is mounted on the frame via the mounting assembly, which includes a limiting rod and a first monitoring unit. The test connector has a mounting through hole, through which the limiting rod passes and is assembled with the test connector. The first monitoring unit is disposed on the surface of the limiting rod and is used to detect the load on the test connector.

[0010] Preferably, the vertical cross-section of the limiting rod is I-shaped, the limiting rod is a cylinder, and its upper part is a detachable height limiting block.

[0011] Preferably, it further includes a soil constraint unit, which is used to simulate the lateral force of the soil layer on the self-anchor pipe; the soil constraint unit includes a mounting frame, a holding member, and a transmission member; the mounting frame is mounted on the frame and consists of two sections, the holding member and the transmission member are coaxially mounted with the mounting frame and located inside the mounting frame, and the number of holding members is three; the three holding members are respectively connected to the transmission member, and the transmission member is used to drive the three holding members to move radially along the self-anchor pipe.

[0012] Preferably, the transmission component includes a stabilizing platform, a transmission shaft, a transmission block, and a connecting block; the stabilizing platform is fixedly disposed inside the mounting frame and is a concentric ring, and the transmission block converts the rotational motion of the transmission shaft into the radial movement of the connecting block along the anchor pipe.

[0013] Preferably, the drive shaft is mounted on the stabilizing platform and has a gear on its outer periphery; one side of the drive block has a straight tooth portion that meshes with the gear; the top of the drive block is also provided with a plurality of inclined sliding grooves, which are slidably connected to a sliding portion provided at the bottom of the connecting block; the mounting bracket is radially provided with a guide groove, and the connecting block is slidably mounted on the guide groove.

[0014] Preferably, it further includes a vibration assembly for driving the two mounting brackets to vibrate; the vibration assembly includes a driver, a vibration arm, and a control system; the driver is fixedly mounted on the side of the frame, one end of the vibration arm is connected to the output shaft of the driver, and the other end is connected to the outside of the mounting bracket to drive the mounting bracket to vibrate; the control system is electrically connected to the driver and is used to adjust the frequency and amplitude of the vibration.

[0015] Preferably, it also includes a system analysis unit. The first monitoring unit is multiple and is respectively set at the connection of the two test joints and the two self-anchoring pipes, for synchronously monitoring the dynamic load of the three test points excited by the vibration component during the vibration process. The system analysis unit is communicatively connected to the first monitoring unit and is used to analyze the transmission and attenuation law of the vibration wave based on the phase difference and amplitude change rate of the dynamic load.

[0016] Preferably, it further includes a displacement monitoring unit and a dynamic constraint control unit; the displacement monitoring unit is used to monitor the rotation angle of the test point; the system analysis unit calculates the dynamic bending stiffness of each test point in real time during the vibration process based on the dynamic load monitored by the first monitoring unit and the dynamic rotation angle monitored by the displacement monitoring unit; the dynamic constraint control unit is communicatively connected to the system analysis unit and is used to adjust the radial constraint force applied by the soil constraint unit to the self-anchor pipe in real time according to the change of dynamic bending stiffness, so as to simulate the dynamic constraint effect of soil on pipeline vibration response.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention constructs a continuous environment for the pipeline system through a three-test-point series structure, enabling accurate measurement of load transfer and distribution between interfaces. The flexible constraint design of the installation components effectively simulates the actual boundary conditions of the pipeline, avoiding stress distortion caused by rigid clamps. Combined with adjustable soil constraints and dynamic monitoring, it can accurately reflect the mechanical behavior of the pipeline under different burial environments, providing more reliable experimental data for pipeline performance testing. Attached Figure Description

[0019] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0020] Figure 1 This is a front view of the transverse vibration testing machine provided in one embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the self-anchoring pipe anchoring state structure provided in one embodiment of the present invention;

[0022] Figure 3 This is a schematic cross-sectional view of a soil constraint unit provided in one embodiment of the present invention;

[0023] Figure 4 This is a top view of the transverse vibration testing machine provided in one embodiment of the present invention;

[0024] Legend: 1. Frame; 2. Mounting assembly; 21. Limiting rod; 22. First monitoring unit; 3. Soil restraint unit; 31. Mounting frame; 32. Wrapping component; 331. Stabilizing platform; 332. Drive shaft; 333. Drive block; 334. Connecting block; 335. Guide groove; 4. Sliding groove; 5. Vibration assembly; 51. Driver; 52. Vibration arm; 6. Test connector; 7. Self-anchoring pipe. Detailed Implementation

[0025] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0026] Traditional self-anchored pipe 7-interface testing uses a single-interface mode, rigidly anchoring both ends of the interface under test and testing in isolation. This method cannot simulate the continuous effect of dozens or hundreds of interfaces connected in series in a real pipeline system, and ignores the transfer and distribution of load between adjacent interfaces. This results in overly idealized test results, which cannot reflect the actual stress and deformation state of a specific interface in the entire pipeline chain under actual working conditions such as temperature changes and foundation settlement. It is difficult to accurately assess its safety and reliability.

[0027] like Figures 1-4 As shown, a transverse vibration testing machine for a fully self-anchored joint steel pipe includes a frame 1 and an installation assembly 2. The frame 1 is a rectangular frame constructed from several steel frames. Test joints 6 are respectively provided at both ends of the frame 1. Two self-anchored pipe sections 7 are connected, and the other two sections are self-anchored to the two test joints 6 respectively, forming three series test points. During the test, the series pipe sections are subjected to transverse vibration by external excitation. The vibration load will pass through the three test points in sequence. Due to the flexibility of the joint, the load will be redistributed during the transmission process. The deformation of each joint will be constrained and affected by the adjacent joints. The first monitoring unit 22 monitors the load of each test point in real time, thereby capturing the dynamic response of each joint and its mutual coupling relationship when the vibration wave propagates in the pipeline system, and obtaining systematic mechanical data.

[0028] Traditional rigid clamps completely lock the pipe section, failing to simulate the non-perfectly rigid constraint of adjacent pipe sections on the interface in a real piping system. The test connector 6 is mounted on the frame 1 via mounting assembly 2, which includes a limiting rod 21 and a first monitoring unit 22. The test connector 6 has a mounting through-hole, through which the limiting rod 21 passes and assembles with the test connector 6. The first monitoring unit is located on the surface of the limiting rod 21 and is used to detect the load on the test connector 6. The mounting assembly 2 forms an assembly connection through the limiting rod 21 passing through the mounting through-hole of the test connector 6. This limiting rod 21 does not completely lock the connector but rather uses a clearance fit to... It provides controllable flexible constraints, allowing the test joint 6 to undergo small relative displacements under lateral vibration excitation. During this process, the vibration load is transmitted to the test joint 6 through the pipeline and further acts on the limiting rod 21, causing it to generate corresponding strain. The first monitoring unit 22, which is directly fixed to the surface of the limiting rod 21, senses the strain in real time and converts it into an electrical signal output, thereby measuring the dynamic load borne by the test joint 6. This achieves direct and quantitative acquisition of the boundary reaction force of the pipeline system, solving the problems of stress concentration and boundary condition distortion caused by simple rigid support, and making the load applied to the interface more realistic.

[0029] In traditional testing, limiting mechanisms are often single-function, either completely rigidly fixed or lacking precise displacement control capabilities. They cannot provide the necessary support stiffness while flexibly adjusting and limiting the displacement amplitude of the interface during vibration. In one embodiment, the vertical cross-section of the limiting rod 21 is I-shaped, and the limiting rod 21 is a cylinder with a detachable height limiting block at the top. The limiting rod 21 is designed as a composite functional structure: the I-shaped vertical cross-section ensures excellent bending stiffness in the direction of force to provide stable constraints; the cylindrical shape of the rod facilitates smooth adjustment or rotational freedom in the through hole of the test joint 6; during vibration testing, when the pipeline system undergoes lateral deformation, the test joint 6 moves accordingly, and its movement amplitude is constrained by the limiting rod 21, thereby further simulating the real self-anchoring state of the multi-segment self-anchoring pipe 7, and realizing displacement control under flexible constraints through the rigid constraint of the limiting rod 21, improving the simulation capability and flexibility of the testing machine.

[0030] Traditional pipeline testing is conducted in air, completely ignoring the wrapping and constraint effect of soil on the pipe body in the actual laying environment. Testing with insufficient soil constraint cannot reflect the critical working condition of pipe-soil interaction, reducing the authenticity of the test data. In one embodiment, a soil constraint unit 3 is also included. The soil constraint unit 3 is used to simulate the lateral force of the soil layer on the self-anchored pipe 7. The soil constraint unit 3 includes a mounting frame 31, a retaining component 32, and a transmission component. The mounting frame 31 is mounted on the frame 1 and consists of two sections. The retaining component 32 and the transmission component are coaxially mounted with the mounting frame 31 and located inside the mounting frame 31. The number of retaining components 32 is three. Each of the three holding pieces 32 is connected to a transmission component, which drives the three holding pieces 32 to move radially along the self-anchoring pipe 7. During operation, the transmission component receives a control signal and drives the three holding pieces 32 to move synchronously toward or away from the center along the radial direction of the mounting frame 31, thereby gripping the outer wall of the pipe from three directions and applying a settable radial pressure. The applied pressure is equivalent to the lateral earth pressure exerted by the soil on the pipe. During vibration testing, the constraint force is continuous. When the pipe undergoes lateral deformation, the holding piece 32 provides continuous lateral resistance. Its force is collected in real time by the first monitoring unit 22, thereby completely reproducing the vibration response of the pipe constrained in the soil.

[0031] In this embodiment, three radially movable holding members 32 are used to form a dynamic constraint ring. The opening and closing of the ring are precisely controlled by the transmission component. The three-part structure is superior to the integral ring hoop, which can better simulate the non-uniform constraint characteristics of the soil and realize the dynamic loading and unloading of the constraint force, thus reproducing the interaction environment between the pipeline and the soil.

[0032] In the prior art, the mechanism for driving the radial movement of the holding member 32 often suffers from insufficient stability, low transmission efficiency, or inability to guarantee the synchronous movement of the three holding members 32. This leads to uneven constraint force applied to the pipe, making it impossible to accurately simulate the lateral pressure of real soil on the pipe in a uniform or specific distribution around the circumference. In one embodiment, the transmission component includes a stabilizing platform 331, a transmission shaft 332, a transmission block 333, and a connecting block 334. The stabilizing platform 331 is fixedly installed inside the mounting frame 31 and is a concentric ring. The transmission block 333 converts the rotational motion of the transmission shaft 332 into the radial movement of the connecting block 334 along the anchor pipe 7. Furthermore, the transmission shaft 332 is mounted on the stabilizing platform 331 and has gears on its outer periphery. One side of the transmission block 333 has a straight tooth portion that meshes with the gears. The top of the transmission block 333 is also provided with several inclined sliding grooves 4, which are slidably connected to the sliding portion at the bottom of the connecting block 334. The mounting frame 31 is radially provided with a guide groove 335, and the connecting block 334 is slidably mounted on the guide groove 335.

[0033] The drive shaft 332 rotates, and through the meshing of the gear and the spur gear, the drive block 333 is constrained in its direction of movement by the rod that passes through it, so that the drive block 333 moves axially horizontally along the stable platform 331. When the drive block 333 moves, the inclined sliding groove 4 at its top moves relative to the sliding part at the bottom of the connecting block 334. Since the connecting block 334 is constrained by the radial guide groove 335 on the mounting bracket 31, it can only move radially along the pipe. The inclined surface of the sliding groove 4 forces the connecting block 334 to produce an upward radial displacement, thereby pushing the holding member 32 to press against the pipe wall. Reverse rotation of the drive shaft 332 will release it, efficiently converting the rotational motion into radial linear motion. The transmission chain is short and the rigidity is good, ensuring that the constraint force applied to the three holding members 32 is highly synchronized and uniform.

[0034] In one embodiment, a vibration assembly 5 is further included for driving the two mounting brackets 31 to vibrate; the vibration assembly 5 includes a driver 51, a vibrating arm 52, and a control system; the driver 51 is fixedly mounted on the side of the frame 1, one end of the vibrating arm 52 is connected to the output shaft of the driver 51, and the other end is connected to the outside of the mounting bracket 31, driving the mounting bracket 31 to vibrate; the control system is electrically connected to the driver 51 and is used to adjust the frequency and amplitude of the vibration. The control system sends a start command to the driver 51, and the output shaft of the driver 51 begins to rotate, driving the vibrating arm 52 fixed thereon to perform circular motion; due to The other end of the vibrating arm 52 is movably connected to the outside of the mounting frame 31. When the vibrating arm 52 rotates with the output shaft, the arc motion trajectory generated at its end abuts against the mounting frame 31, causing the mounting frame 31 to vibrate. As the output shaft continues to rotate, the vibrating arm 52 periodically pushes and pulls the mounting frame 31, causing it to generate stable vibration within the lateral constraint range. During this process, the control system controls the vibration frequency by adjusting the rotation speed of the driver 51 in real time and controls the amplitude by limiting the rotation angle of the output shaft, thereby achieving regulation of the vibration characteristics of the mounting frame 31. The vibration component 5 causes the connected self-anchor pipe 7 to vibrate, simulating the environment of uneven settlement of the self-anchor pipe 7 in the soil layer, further testing the connection stability at the connection point.

[0035] Traditional single-interface testing can only measure static or single dynamic loads and cannot capture the propagation characteristics of vibration loads between continuous interfaces in a piping system. Due to the lack of multi-point synchronous monitoring and correlation analysis, it is impossible to know the key dynamic parameters such as energy attenuation, transmission speed, and phase change of the vibration wave when passing through each interface. Therefore, it is difficult to evaluate the overall response performance and wave propagation mechanism of the pipeline system under dynamic load. In one embodiment, a system analysis unit is also included. Multiple first monitoring units 22 are respectively set at the connection points of the two test joints 6 and the two self-anchoring pipes 7. They are used to synchronously monitor the dynamic load of the three test points excited by the vibration component 5 during the vibration process. The system analysis unit is communicatively connected to the first monitoring unit 22. It is used to analyze the transmission and attenuation law of the vibration wave based on the phase difference and amplitude change rate of the dynamic load. The system analysis unit synchronously collects the dynamic load time series data of the three test points during the vibration process. By calculating the time delay between the load signals of the downstream measuring point and the upstream measuring point, it analyzes the transmission speed of the vibration wave crossing the interface. By calculating the ratio of the load amplitude of adjacent measuring points, it quantifies the degree of energy attenuation of the vibration wave during the transmission process, the propagation law of the vibration wave in the pipeline system, and the dynamic characteristics of each interface.

[0036] Soil constraint unit 3 can typically only apply constant static pressure, failing to simulate the dynamic constraint response of real soil due to its elastic-plastic properties during pipeline vibration. In one embodiment, it further includes a displacement monitoring unit and a dynamic constraint control unit. The displacement monitoring unit monitors the rotation angle of the test point. The system analysis unit calculates the dynamic bending stiffness of each test joint during vibration in real time based on the dynamic load monitored by the first monitoring unit 22 and the dynamic rotation angle monitored by the displacement monitoring unit. The dynamic constraint control unit is communicatively connected to the system analysis unit and is used to adjust the radial constraint force applied by the soil constraint unit 3 to the self-anchor pipe 7 in real time according to the change in dynamic bending stiffness, so as to simulate the dynamic constraint effect of soil on pipeline vibration response. The measurement unit 22 synchronously collects the rotation angle and load of the interface. The system analysis unit calculates the dynamic bending stiffness in real time and instructs the dynamic constraint control unit to adjust the radial force of the soil constraint unit 3 accordingly, thus realizing the physical simulation of the dynamic constraint effect of the soil. The system analysis unit receives the load and rotation angle signals in real time and calculates the dynamic bending stiffness of each interface. The dynamic bending stiffness reflects the flexibility of the interface under instantaneous vibration. If the stiffness decreases, it indicates that the interface deformation increases. The system then determines that the pipeline needs stronger soil constraint and instructs the dynamic constraint control unit to increase the radial pressure of the wrapping component 32, and vice versa. This dynamically simulates the constraint change of the soil and realizes the laboratory simulation of the dynamic interaction between the pipeline and the soil, which greatly improves the realism of the pipeline system test under complex dynamic loads.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A transverse fatigue testing machine for a self-anchored joint of a steel pipe, characterized by, It includes a frame and mounting components. The frame is a rectangular frame constructed from several steel frames. Test connectors are provided at both ends of the frame. Two sections are connected by self-anchored pipes, and the other two sections are self-anchored to two test connectors respectively, forming three test points in series. The test connector is mounted on the frame via the mounting assembly, which includes a limiting rod and a first monitoring unit. The test connector has a mounting through hole, through which the limiting rod passes and is assembled with the test connector. The first monitoring unit is disposed on the surface of the limiting rod and is used to detect the load on the test connector. The vertical cross-section of the limiting rod is I-shaped, and the limiting rod is a cylinder with a detachable height limiting block at its upper part. It also includes a soil constraint unit, which is used to simulate the lateral force of the soil layer on the self-anchor pipe; the soil constraint unit includes a mounting frame, a holding component, and a transmission component; the mounting frame is mounted on the frame and consists of two sections, the holding component and the transmission component are coaxially mounted with the mounting frame and located inside the mounting frame, and the number of holding components is three; the three holding components are respectively connected to the transmission component, and the transmission component is used to drive the three holding components to move radially along the self-anchor pipe.

2. The transverse fatigue testing machine for self-anchored steel pipe joints according to claim 1, characterized in that, The transmission component includes a stabilizing platform, a transmission shaft, a transmission block, and a connecting block; the stabilizing platform is fixedly disposed inside the mounting frame and is a concentric ring, and the transmission block converts the rotational motion of the transmission shaft into the radial movement of the connecting block along the self-anchor pipe.

3. The transverse fatigue testing machine for self-anchored steel pipe joints according to claim 2, characterized in that, The drive shaft is mounted on the stabilizing platform and has gears on its outer periphery. One side of the drive block has a straight toothed portion that meshes with the gears. The top of the drive block also has several inclined sliding grooves, which are slidably connected to the sliding portion at the bottom of the connecting block. The mounting bracket has guide grooves radially, and the connecting block is slidably mounted on the guide grooves.

4. The transverse fatigue testing machine for self-anchored steel pipe joints according to claim 1, characterized in that, It also includes a vibration assembly for driving the two mounting brackets to vibrate; the vibration assembly includes a driver, a vibration arm and a control system; the driver is fixedly mounted on the side of the frame, one end of the vibration arm is connected to the output shaft of the driver and the other end is connected to the outside of the mounting bracket to drive the mounting bracket to vibrate; the control system is electrically connected to the driver and is used to adjust the frequency and amplitude of the vibration.

5. A transverse fatigue testing machine for self-anchored steel pipe joints according to claim 4, characterized in that, It also includes a system analysis unit. The first monitoring unit consists of multiple units, which are respectively set at the connection points of the two test joints and the two self-anchoring pipes. They are used to synchronously monitor the dynamic load of the three test points excited by the vibration component during the vibration process. The system analysis unit is communicatively connected to the first monitoring unit and is used to analyze the transmission and attenuation law of the vibration wave based on the phase difference and amplitude change rate of the dynamic load.

6. The transverse fatigue testing machine for self-anchored steel pipe joints according to claim 5, characterized in that, It also includes a displacement monitoring unit and a dynamic constraint control unit; the displacement monitoring unit is used to monitor the rotation angle of the test point; the system analysis unit calculates the dynamic bending stiffness of each test point in real time during the vibration process based on the dynamic load monitored by the first monitoring unit and the dynamic rotation angle monitored by the displacement monitoring unit; the dynamic constraint control unit is communicatively connected to the system analysis unit and is used to adjust the radial constraint force applied by the soil constraint unit to the self-anchor pipe in real time according to the change of dynamic bending stiffness, so as to simulate the dynamic constraint effect of soil on pipeline vibration response.

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