LNG ultralow-temperature-resistant pipeline tension-torsion test experimental device and test method

Abstract

The invention relates to an LNG ultralow-temperature-resistant pipeline tension-torsion test experimental device and a test method. The device comprises a tensile test mechanism, a torsion test mechanism, a data acquisition mechanism and a pressurization mechanism, the stretching testing mechanism comprises a stretching driving mechanism, a stretching transmission mechanism and a stretching supporting mechanism and is used for simulating the real stretching condition of the LNG flexible pipeline; the torsion testing mechanism comprises a torsion driving mechanism, a torsion transmission mechanism and a torsion supporting mechanism and is used for simulating the real torsion condition of the LNG flexible pipeline; and the pressurizing mechanism is used for injecting gas into the LNG flexible pipeline, increasing gas pressure and simulating a real environment. The data acquisition mechanism records torque and tension data through the torque sensor and the tension driver, and monitors the condition of the LNG flexible pipeline in real time through the camera, so that the critical value during fatigue failure of a test piece in a fatigue mechanical property test is obtained, the overall structure avoids complexity and redundancy of the mechanism, and the space utilization rate can be increased as much as possible.

Description

Technical Field

[0001] The invention belongs to the technical field of LNG flexible pipeline testing, and in particular relates to an experimental device and method for LNG ultra-low temperature resistant pipeline tension and torsion testing. Background Art

[0002] The LNG flexible pipeline tension and torsion combined test device is mainly based on the safety and reliability requirements of flexible pipes and cables in marine engineering. As the difficulty of exploitation of terrestrial oil and gas resources increases and resources are gradually depleted, the development of marine oil and gas resources has become increasingly important. The particularity of the marine environment requires the use of specialized marine oil and gas exploitation equipment, among which flexible pipes and cables have attracted much attention due to their irreplaceable role in marine oil and gas exploitation and transportation.

[0003] In order to ensure the safety of flexible cables during underwater use, they need to be subjected to rigorous mechanical property tests. Traditional testing methods are mainly aimed at single working conditions, such as tension, compression, bending and torsion, but the test of tension-torsion coupling conditions has not yet been systematically established. Since marine flexible cables have a long service life in the deep sea, it is crucial to conduct systematic mechanical property tests on them and fully understand their stress characteristics in order to accurately predict their service life.

[0004] Existing test equipment and methods are mostly based on the superposition of single working conditions to achieve the coupling of combined working conditions, which has problems such as complex test operation, easy errors in testing and low test accuracy. Therefore, the development of a new type of tension-torsion combined test device can realize the performance test of flexible pipes and cables under tension-torsion coupling conditions, which is of great significance for improving test efficiency and accuracy and ensuring the reliability of pipes and cables. Traditional hose tension detection devices usually only detect a single item of tension or torque, and cannot simulate the actual situation of LNG.

[0005] Existing LNG flexible pipeline testing experiments require special requirements for equipment and materials in low-temperature environments. Traditional testing devices are usually carried out at room temperature and cannot simulate real conditions. Under ultra-low temperature conditions, traditional tensile test fixtures are prone to failure due to the cooling effect of liquid nitrogen in the cryogenic box, resulting in insufficient or loose specimen clamping, which affects the accuracy of the test results. Summary of the invention

[0006] The purpose of the present invention is to provide an LNG ultra-low temperature resistant pipeline tension and torsion test experimental device and test method to solve the problems raised in the above background technology.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] An LNG ultra-low temperature resistant pipeline tension and torsion test experimental device, comprising: a tension test mechanism, a torsion test mechanism, a data acquisition mechanism, and a pressurization mechanism;

[0009] The tensile testing mechanism comprises a tensile driving mechanism and a tensile transmission mechanism, wherein the tensile driving mechanism and the tensile transmission mechanism are installed on a tensile supporting mechanism and are used to simulate the actual retraction and tensioning conditions of the LNG flexible pipeline;

[0010] The torsion testing mechanism includes a torsion driving mechanism, a torsion transmission mechanism, and a torsion supporting mechanism, which are used to simulate the real torsion condition of the LNG flexible pipeline;

[0011] The data acquisition mechanism includes a torque sensor, a tension sensor and a camera. The torque sensor is installed on a torque sensor fixing seat. The tension sensor is connected to the test bench through floating joints A and B. The camera is installed outside the water tank to collect torque, tension information and LNG flexible pipeline conditions for further analysis.

[0012] The pressurizing mechanism includes a gas pressurizing pump, a rubber ring, and a pipeline, which are used to inject gas into the LNG flexible pipeline to increase the gas pressure and simulate the real environment.

[0013] Furthermore, the stretching drive mechanism includes a servo motor 1, the servo motor 1 is connected to a reducer 1, and the reducer 1 is installed on the upper part of the fixed flange seat.

[0014] Furthermore, the stretching transmission mechanism includes a left guide rail and a right guide rail, a slider C and a slider D are installed on the left guide rail, and a slider A and a slider B are installed on the right guide rail, the sliders A, B, C and D are installed at the bottom of the fixed flange seat, the reducer 1 is connected to the gear installed on the base through key 3, the gear is meshed with the rack, and the stretching transmission mechanism realizes the movement of the fixed flange seat along the direction of the rack, and the torque output by the reducer is converted into horizontal pulling force through the meshing of the gear and the rack.

[0015] Furthermore, the stretching support mechanism includes a test bench and a fixed flange seat, wherein the fixed flange seat is used to fix the servo motor 1 and the reducer 1; the fixed flange seat is connected to the slider A, the slider B, the slider C, and the slider D to ensure their horizontal movement.

[0016] Furthermore, the torsion drive mechanism includes a second servo motor, the second servo motor is connected to a second reducer, and the second reducer is mounted on a motor fixing seat.

[0017] Further, the torsion transmission mechanism includes a large gear and a small gear, the small gear is installed on the small gear shaft through a key, the small gear shaft is connected to the reducer 2 through a coupling 3, the small gear is meshed with the large gear, and the conversion from high speed and low torque to low speed and high torque is realized through the transmission of the large gear and the small gear;

[0018] The large gear is connected to the torsion flange shaft one through key one, the torsion flange shaft one is connected to the torsion flange shaft two, one end of the torsion flange shaft two is fixed on the base through bearing three; the torsion flange shaft two is connected to coupling two, a torque sensor is provided between coupling two and coupling one, the coupling one is connected to the torsion flange shaft three, and the torsion flange shaft three is installed on the water tank through bearing four, thereby ensuring the smooth transmission of torque.

[0019] Furthermore, the torsion support mechanism includes a motor fixing seat and a torque sensor fixing seat, the motor fixing seat is mounted on the base, and the torque sensor is mounted on the sensor fixing seat.

[0020] Furthermore, the data acquisition mechanism includes a torque sensor, a tension sensor, and a camera, the torsion sensor, tension sensor, and camera are respectively connected to a computer, the computer is connected to a display, the camera is mounted on a tripod and positioned outside the water tank, and the lens of the camera faces the water tank so that it can clearly capture the LNG flexible pipeline, which is used for the entire process of the LNG flexible pipeline from torsion to fracture.

[0021] The present invention may also include: a testing method for the LNG ultra-low temperature resistant pipeline tension and torsion testing experimental device as described above, comprising the following steps:

[0022] (1) Assemble all parts and mechanisms to obtain a test device, turn off the switches of servo motor 1 and servo motor 2, fix one end of the test piece to the torsion flange shaft 3 by bolts, and fix the other end of the test piece to the water tank by bolts and fix it with a locking ring to ensure that the LNG is in a horizontal state;

[0023] (2) After completing the above work, complete the preliminary debugging of the test device: turn on the torque sensor, tension sensor, computer and camera to ensure their normal operation; turn on the servo motor 1 and servo motor 2 of the tensile test mechanism and the torsion test mechanism respectively to load the LNG with a small amplitude, observe the recording of the torque sensor, tension sensor, computer and camera, and turn off the motor when the test requirements are met, and then start the test;

[0024] (3) Based on the test requirements, liquid nitrogen was injected into the water tank and the gas pressure pump was turned on to simulate the real environment;

[0025] (4) According to the experimental requirements of selecting a tensile test, a torsion test, or a tension-torsion test combination, select servo motor 1 of the tensile test mechanism and servo motor 2 of the torsion test mechanism to open, and select the corresponding motor speed according to the required tension and torque, and observe the computer data and record it at the same time.

[0026] Furthermore, the camera captures the entire deformation process of LNG, and at the same time, analyzes and processes the data collected by the torque sensor, the tension sensor and the camera, and finally compares the theoretical calculation results, and combines the two results to obtain the stress condition and life calculation of LNG.

[0027] The beneficial effects of the present invention are:

[0028] The supporting mechanism of the present invention is fixed on the experimental table, the tensile test structure is driven by a servo motor, and the torque is converted into tension through the meshing transmission of the gear rack, and the torsion test structure is driven by a motor, and the high speed and low torque are converted into low speed and high torque through the meshing transmission of the small gear and the large gear, thereby simulating the actual stress situation of the specimen LNG flexible pipeline (specimen), and at the same time, the pressurizing mechanism injects gas into the LNG flexible pipeline, and liquid nitrogen is added into the water tank to simulate the actual operation of LNG. The data acquisition mechanism records the torque and tension data through the torque sensor and the tension transmission device, and monitors the situation of the LNG flexible pipeline in real time through the camera, so as to obtain the critical value of the fatigue failure of the specimen in the fatigue performance test.

[0029] The servo motor and reducer of the torsion transmission mechanism of the present invention can be used as a torque transmission mechanism. The torsion transmission mechanism converts the high speed and low torque of the motor into low speed and high torque, thereby making it suitable for the needs of the device and ensuring its stability in the experiment.

[0030] In order to better obtain the corresponding torque, the present invention adds necessary torque sensors and tension sensors to the designed transmission mechanism, so that when the test piece is determined, the fatigue testing machine of the present invention can directly obtain the critical value of fatigue failure of the test piece in the fatigue performance test.

[0031] The present invention uses a servo motor, which avoids the complexity and redundancy of the mechanism and can maximize the space utilization. At the same time, it optimizes the positioning accuracy, speed control and dynamic response to the greatest extent. It has high torque density and achieves excellent torque in the entire speed range.

[0032] The present invention can simulate the actual working situation of the LNG flexible pipeline more realistically by injecting liquid nitrogen into the water tank and injecting pressure into the pipe through the pressurizing system.

[0033] The present invention can flexibly select a combination method of tension and torque, and can flexibly adjust tension and torque by adjusting the motor speed, so as to simulate various real situations and be widely promoted in the fields of LNG flexible pipeline torsion testing, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Attached Figure 1 It is a structural schematic diagram of the present invention.

[0035] Attached Figure 2It is the front view of the present invention.

[0036] Attached Figure 3 This is a partial structural cross-sectional view of the torsion transmission mechanism of the present invention. Figure 1 .

[0037] Attached Figure 4 This is a partial structural cross-sectional view of the torsion transmission mechanism of the present invention. Figure 2 .

[0038] Attached Figure 5 Yes Figure 2 Left view of .

[0039] Attached Figure 6 It is a schematic diagram of the present invention when the test piece is not installed.

[0040] The above drawings include the following reference numerals:

[0041] 1. Servo motor 1; 2. Reducer 1; 3. Fixed flange seat; 4. Left guide rail; 5. Rack; 6. Test bench; 7. Right guide rail; 8. Slider A; 9. Slider B; 10. Computer; 11. Tripod; 12. Camera; 13. Torque sensor fixed seat; 14. Coupling 1; 15. Torque sensor; 16. Coupling 2; 17. Torsion flange shaft 2; 18. Pinion; 19. Motor fixed seat; 20. Coupling 3; 21. Reducer 2; 22. Servo motor 2; 23. Large gear; 24. Torsion flange shaft one; 25. Base; 26. Torsion flange shaft three; 27. Gas booster pump; 28. Pipeline; 29. ​​Water tank; 30. Test piece; 31. Locking ring; 32. Floating joint A; 33. Tension sensor; 34. Floating joint B; 35. Slider D; 36. Slider C; 37. Key two; 38. Bearing one; 39. Shaft; 40. Bearing two; 41. Key one; 42. Bearing three; 43. Bearing; 44. Gear; 45. Key three. DETAILED DESCRIPTION

[0042] It should be noted that, in the absence of conflict, the examples and features in the examples of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with examples.

[0043] In order to make the purpose, technical solution and advantages of the examples of the present invention clearer, the technical solution in the examples of the present invention will be clearly and completely described below in conjunction with the drawings in the examples of the present invention. Obviously, the described examples are only part of the examples of the present invention, not all of the examples. The following description of at least one exemplary example is actually only illustrative and is by no means a limitation on the present invention and its application or use. Based on the examples in the present invention, all other examples obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the term "comprising" or "including" is used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0045] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values ​​set forth in these examples do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary examples may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0046] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0047] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0048] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0049] According to an embodiment of the present invention, a LNG ultra-low temperature resistant pipeline tension and torsion test experimental device is provided, comprising: a tensile test mechanism, a torsion test mechanism, a data acquisition mechanism, a pressurization mechanism; a torque data acquisition mechanism, which is used to collect torque information;

[0050] The tensile testing mechanism described in this embodiment includes: a tensile driving mechanism, a tensile transmission mechanism, and a tensile supporting mechanism. The tensile driving mechanism is used to provide torque; the tensile transmission mechanism is used to convert the torque into tension and transmit the tension to the LNG flexible pipeline; the tensile supporting mechanism is used to fix each mechanism to maintain stability.

[0051] The following is a description of the drawings. Figure 1 As shown, the stretching drive mechanism includes a servo motor 1 and a reducer 2, and the reducer 2 converts the high speed and low torque of the servo motor 1 into a low speed and high torque.

[0052] As attached Figure 5 As shown, reducer 2 and gear 44 are connected via key 3 45 .

[0053] As attached Figure 1 , 5As shown, the stretching transmission mechanism includes a gear 44, a rack 5, a left guide rail 4, a right guide rail 7, a slider A8, a slider B9, a slider C36, a slider D35, and a fixed flange seat 3. The left guide rail 4 and the right guide rail 7 are installed on the experimental table, the slider A8 and the slider B9 are installed on the right guide rail 7, the slider C36 and the slider D35 are installed on the left guide rail 4, the slider A8, the slider B9, the slider C36 and the slider D35 are connected to the fixed flange seat 3 by screws, the servo motor 1 and the reducer 2 are installed on the fixed flange seat 3, and the torque output by the reducer 2 is converted into a horizontal pulling force through the meshing of the gear 44 and the rack 5.

[0054] As attached Figure 1 As shown, one end of the test piece 31 is fixed to the water tank 29 using a locking ring 31. During the test, the test piece 31 and the fixed flange seat 3 transmit the tensile force to the test piece through the locking ring 3.

[0055] Through the above embodiments, the tensile testing mechanism of the present invention is used to simulate the actual tensioning condition of the LNG flexible pipeline.

[0056] The torsion testing mechanism described in this embodiment includes: a torsion driving mechanism, a torsion transmission mechanism, and a torsion support mechanism, wherein the torsion testing mechanism is used to provide torque; the torque transmission mechanism is used to transfer the torque to the LNG flexible pipeline and convert high speed and low torque into low speed and high torque; the torsion support mechanism is used to fix each mechanism to keep it stable.

[0057] The following is a description of the drawings. Figure 1 As shown, the torque driving mechanism includes a servo motor 22 and a reducer 21. The reducer 21 is connected to the servo motor 22, and the reducer 21 converts the high speed and low torque of the servo motor 22 into a low speed and high torque.

[0058] The torque transmission mechanism includes a large gear 23, a small gear 18, a torsion flange shaft 1 24, a torsion flange shaft 2 17, and a coupling 2 16. The reducer 21 and the shaft 39 are connected together by a key 37, the large gear 23 and the torsion flange shaft 2 17 are connected together by a key 41, the reducer 21 drives the shaft 39 to rotate through the coupling 2 16, the shaft 39 and the large gear 18 are meshed for transmission, the large gear 18 and the torsion flange shaft 1 24 are connected together by bolts, and the torsion flange shaft 1 24 and the torsion flange shaft 2 17 are connected together by bolts.

[0059] As attached Figure 3 As shown, one end of the shaft 39 is fixed to the motor fixing seat 19 through a bearing 1 38 , and the other end is installed on the base 25 through a bearing 2 40 , which ensures the smooth rotation of the shaft 39 .

[0060] As attached Figure 1As shown, one end of the test piece 30 is fixed to the torsion flange shaft three 26 by bolts. The test piece 30 is the LNG flexible pipeline. During the test, the test piece 30 and the torsion flange shaft three 26 are connected by bolts to transmit the torque to the test piece 30.

[0061] As attached Figure 4 As shown, one end of the torsion flange shaft 2 17 is fixed to the base 25 through the bearing 3 42, and the other torsion flange shaft 3 26 is installed on the water tank 29 through the bearing 4 43, which ensures the smooth transmission of torque.

[0062] The tension sensor model in this embodiment is KD40S, and the tension range of this tension sensor is 0 to 10 kN.

[0063] Through the above embodiments, the torsion testing mechanism of the present invention is used to simulate the actual torsion condition of the LNG flexible pipeline.

[0064] The reducer 1 and reducer 2 described in the above implementation are worm gear reducers, and their output speed range is 40-50r / min and their output power is 0.85kW.

[0065] The servo motor 1 and the servo motor 2 are MSME-1000 servo motors.

[0066] The bearings are deep groove ball bearings. The one connected to the shaft is a 6208 deep groove ball bearing, and the one connected to the torsion flange shaft is a 6213 deep groove ball bearing.

[0067] The data acquisition mechanism described in this embodiment includes: a stretching data acquisition mechanism, a torque data acquisition mechanism, and a camera (12).

[0068] The following is a description of the drawings. Figure 1-2 As shown, the tensile data acquisition mechanism includes a tension sensor 33 and a computer 10. One end of the tension sensor 33 is connected to the experimental table through a floating joint A32, and the other end is connected to the fixed flange seat 3 through a floating joint B34. The fixed flange seat 3 can transmit the tension to the tension sensor 33 when being pulled by the slider A8, the slider B9, the slider C36 and the slider D35. The tension sensor 33 is connected to the computer 10.

[0069] The tension sensor model in this embodiment is KD40S, and the tension range of this tension sensor is 0 to 10 kN.

[0070] As attached Figure 1As shown, the torque data acquisition mechanism includes: a torque sensor 15, a computer 10, the torque sensor 15 is installed on the sensor fixing base 13, the sensor fixing base 13 is installed on the base 25 by screws, the torsion flange shaft 2 17 and the torsion flange shaft 3 26 are connected to the torque sensor 15 by the coupling 2 16 and the coupling 1 14 respectively, the torque is transmitted to the torsion flange shaft 26, and the torque sensor 15 is connected to the computer 10.

[0071] The torque sensor described in this embodiment is CYT-302, with a torque measurement range of 0 to 1000 N·m and a rotation speed range of 0 to 1000 r / min.

[0072] Through the above embodiments, the torque data acquisition mechanism of the present invention can clearly capture the LNG flexible pipeline and is used for the entire process from the beginning of torsion to the fracture of the LNG flexible pipeline.

[0073] The camera 12 is installed on the tripod 11 , and the camera 12 is connected to the computer 10 .

[0074] The camera 12 is a high-speed camera, which is used for the entire process from the twisting to the breaking of the LNG flexible pipeline. The sampling frame number of the high-speed camera reaches 60 frames / s, and high frame rate shooting is adopted to collect the breaking time of the LNG flexible pipeline.

[0075] The pressurization system described in this embodiment includes a gas pressure pump, a rubber ring, and a pipeline. The gas pressure pump is connected to the LNG flexible pipeline through a pipeline, and there are rubber rings at both ends of the connection to prevent gas leakage. The gas pressure pump 27 injects gas into the LNG flexible pipeline through the pipeline 28 and adjusts the pressure to 1-5MPa.

[0076] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above examples, those skilled in the art should understand that they can still modify the technical solutions described in the above examples, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the examples of the present invention.

Claims

1. An LNG ultra-low temperature resistant pipeline tension and torsion test experimental device, characterized in that: include: Tensile testing mechanism, torsion testing mechanism, data acquisition mechanism, pressurization mechanism; The tensile testing mechanism comprises a tensile driving mechanism and a tensile transmission mechanism, wherein the tensile driving mechanism and the tensile transmission mechanism are installed on a tensile supporting mechanism and are used to simulate the actual retraction and tensioning conditions of the LNG flexible pipeline; The torsion testing mechanism includes a torsion driving mechanism, a torsion transmission mechanism, and a torsion supporting mechanism, which are used to simulate the real torsion condition of the LNG flexible pipeline; The data acquisition mechanism comprises a torque sensor (15), a tension sensor (33) and a camera (12), wherein the torque sensor (27) is mounted on a torque sensor fixing seat (13), the tension sensor (33) is connected to a test bench (6) via a floating joint A (32) and a floating joint B (34), and the camera (12) is mounted outside a water tank (29) and is used to collect torque, tension information and conditions of the LNG flexible pipeline for further analysis; The pressurizing mechanism comprises a gas pressurizing pump (27), a rubber ring, and a pipeline (28), and is used to inject gas into the LNG flexible pipeline to increase the gas pressure and simulate a real environment.

2. The LNG ultra-low temperature resistant pipeline tension and torsion test experimental device according to claim 1 is characterized in that: The stretching drive mechanism comprises a servo motor (1), the servo motor (1) is connected to a reducer (2), and the reducer (2) is installed on the upper part of a fixed flange seat (3).

3. The LNG ultra-low temperature resistant pipeline tension and torsion test experimental device according to claim 1 or 2 is characterized in that: The stretching transmission mechanism comprises a left guide rail (4) and a right guide rail (7); a slider C (36) and a slider D (35) are installed on the left guide rail (4); a slider A (8) and a slider B (9) are installed on the right guide rail; the slider A (8), the slider B (9), the slider C (36) and the slider D (35) are installed at the bottom of the fixed flange seat (3); the reducer 1 (2) is connected to a gear (44) installed on the base (3) through a key 3 (45); the gear (44) is meshed with a rack (5); the stretching transmission mechanism realizes the movement of the fixed flange seat (3) along the direction of the rack (5); the torque output by the reducer (2) is converted into a horizontal pulling force through the meshing of the gear (44) and the rack (5).

4. The LNG ultra-low temperature resistant pipeline tension and torsion test device according to claim 3 is characterized in that: The stretching support mechanism comprises a test bench (6) and a fixed flange seat (3), wherein the fixed flange seat (3) is used to fix the servo motor 1 (1) and the reducer 1 (2); the fixed flange seat (3) is connected to the slider A (8), the slider B (9), the slider C (36), and the slider D (35) to ensure their horizontal movement.

5. The LNG ultra-low temperature resistant pipeline tension and torsion test experimental device according to claim 1 is characterized in that: The torsion drive mechanism comprises a second servo motor (22), the second servo motor (22) is connected to a second reducer (21), and the second reducer (21) is mounted on a motor fixing seat (19).

6. The LNG ultra-low temperature resistant pipeline tension and torsion test experimental device according to claim 5 is characterized in that: The torsion transmission mechanism comprises a large gear (23) and a small gear (18), wherein the small gear (18) is mounted on a small gear shaft via a key, and the small gear shaft is connected to the second reducer (21) via a coupling (20), and the small gear (18) is meshed with the large gear (23), and the conversion from high speed and low torque to low speed and high torque is achieved through the transmission of the large gear (23) and the small gear (18); The large gear (23) is connected to the torsion flange shaft (24) through a key (41), the torsion flange shaft (24) is connected to the torsion flange shaft (17), one end of the torsion flange shaft (17) is fixed to the base (25) through a bearing (42); the torsion flange shaft (17) is connected to the coupling (16), a torque sensor (15) is provided between the coupling (16) and the coupling (14), the coupling (14) is connected to the torsion flange shaft (26), the torsion flange shaft (26) is installed on the water tank (29) through a bearing (43), thereby ensuring smooth transmission of torque.

7. The LNG ultra-low temperature resistant pipeline tension and torsion test experimental device according to claim 5 or 6, characterized in that: The torsion support mechanism comprises a motor fixing seat (19) and a torque sensor fixing seat (13); the motor fixing seat (19) is mounted on a base (25); and the torque sensor (15) is mounted on the sensor fixing seat (13).

8. The LNG ultra-low temperature resistant pipeline tension and torsion test device according to claim 1 is characterized in that: The data acquisition mechanism comprises a torque sensor (15), a tension sensor (33), and a camera (12); the torque sensor (15), the tension sensor (33), and the camera (12) are respectively connected to a computer (10); the computer (10) is connected to a display; the camera (12) is mounted on a tripod (11) and is located outside a water tank; the lens of the camera (12) faces directly at the water tank (29), so that the camera (12) can clearly capture the LNG flexible pipeline, and is used for the entire process of the LNG flexible pipeline from torsion to fracture.

9. A test method for the LNG ultra-low temperature resistant pipeline tension and torsion test device according to any one of claims 1 to 8, characterized in that: The steps include: (1) Assemble various parts and mechanisms to obtain a test device, turn off the switches of servo motor 1 (1) and servo motor 2 (22) at the same time, fix one end of the test piece (30) to the torsion flange shaft 3 (26) by bolts, and fix the other end of the test piece (30) to the water tank by bolts and fixed with a locking ring (31) to ensure that the LNG is in a horizontal state; (2) After completing the above work, complete preliminary debugging of the test device: turn on the torque sensor, tension sensor, computer and camera to ensure that they are working properly; turn on the servo motor 1 and servo motor 2 of the tensile test mechanism and the torsion test mechanism to load the LNG with a small amplitude, observe the recording of the torque sensor (15), tension sensor (33), computer (10) and camera (12), and turn off the motors after meeting the test requirements, and then start the test; (3) Based on the test requirements, liquid nitrogen is injected into the water tank (29) and the gas pressure pump (27) is turned on to simulate the real environment; (4) According to the experimental requirements of selecting a tensile test, a torsion test, or a tension-torsion test combination, select servo motor 1 of the tensile test mechanism and servo motor 2 of the torsion test mechanism to open, and select the corresponding motor speed according to the required tension and torque, and observe the computer data and record it at the same time.

10. The testing method of the LNG ultra-low temperature resistant pipeline tension and torsion testing experimental device according to claim 9 is characterized in that: The camera (12) captures the entire deformation process of the LNG. At the same time, the data collected by the torque sensor (15), the tension sensor (33) and the camera (12) are analyzed and processed, and finally the theoretical calculation results are compared. The two results are combined to obtain the stress condition and life calculation of the LNG.

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