Flexible composite pipe multifunctional complex load test equipment and test method thereof

Abstract

The invention relates to flexible composite pipe multifunctional complex load test equipment and a test method thereof, and the flexible composite pipe multifunctional complex load test equipment comprises a dynamic stretching-torsion power unit, a test unit, a static torsion unit and an installation auxiliary unit. The dynamic tension-torsion power unit, the test unit and the static torsion unit are coaxially and sequentially connected together, the dynamic tension-torsion power unit is connected with the test unit through a pressure torque load transmission short section, and the other end of the test unit is connected with the static torsion unit through a tension torque load transmission short section; the installation auxiliary unit and the dynamic stretching-twisting power unit are arranged on the installation base frame in parallel, the installation base frame is connected with the base frame guide rail in a sliding mode, and the installation auxiliary unit is composed of a plurality of flexible composite pipe brackets arranged side by side. The mechanical property measurement of the flexible composite pipe under the complex load can be realized, one machine has multiple functions, and the investment and the equipment operation and maintenance cost are greatly reduced.

Description

Technical Field

[0001] The present invention relates to testing equipment for flexible composite pipes under complex loads in the field of flexible composite pipe testing, in particular to multifunctional complex load testing equipment for flexible composite pipes and a testing method thereof. Background Art

[0002] The SY / T 6662 standard for "Non-metallic Composite Pipes for the Petroleum and Natural Gas Industry" covers flexible composite high-pressure transmission pipes, steel-reinforced thermoplastic composite coiled pipes, reinforced ultra-high molecular weight polyethylene composite pipes, and flexible composite pipes for downhole use, collectively referred to as flexible composite pipes. These pipes offer advantages such as single length, lightweight, corrosion resistance, and ease of installation. They have been widely used in key sectors such as oil, gas, and water extraction and transportation, becoming a vital component of oil and gas extraction, gathering, transportation, and reinjection pipeline networks. According to the SY / T 6662 standard, these flexible composite pipes must undergo tests such as short-term clean water pressure, short-term burst pressure, minimum bend radius, short-term cycling pressure, and 1000-hour survival tests before leaving the factory. Each test requires specialized testing equipment. For example, testing short-term clean water pressure requires a short-term clean water pressure tester, testing short-term burst pressure requires a burst testing machine, testing minimum bend radius requires a bend testing machine, and testing 1000-hour survival requires a long-term hydrostatic pressure tester. Various specialized test equipment not only increases laboratory construction investment and equipment operation and maintenance costs, but also significantly increases staff labor intensity. Furthermore, due to the inevitable terrain differences in oil and gas transportation, particularly in the Changqing and Yanchang Oilfields in northern Shaanxi, the Puguang, Yuanba, and Tongnanba Gas Fields in northeastern Sichuan, and the Shunbei Oil and Gas Field in the Tarim Basin, the terrain differences in flexible composite pipe installations subject the pipelines to complex loads of compression, tension, bending, and torsion during service. Long-term fatigue damage to pipelines under these complex loads is a major drawback in flexible composite pipe life prediction research due to a lack of testing equipment for these complex loads.

[0003] In summary, how to develop a set of multifunctional complex load test equipment for flexible composite pipes that can simultaneously meet the needs of various mechanical performance tests of flexible composite pipes, reduce the production and operation costs of enterprises, and carry out pipe performance tests under complex load coupling conditions of compression, tension, bending, and torsion, and provide solid data support for the prediction of the service life of flexible composite pipes under complex working conditions, has become the focus of research by the majority of technical staff.

[0004] Therefore, it is necessary to invent a multifunctional testing equipment and testing method for flexible composite pipes to solve the above problems. Summary of the Invention

[0005] One object of the present invention is to provide a multifunctional complex load testing device for flexible composite pipes, which is used for life prediction research of flexible composite pipes; another object of the present invention is to provide a testing method for the multifunctional complex load testing device for flexible composite pipes.

[0006] The technical solution adopted by the present invention to solve its technical problems is: this flexible composite pipe multifunctional complex load testing equipment includes an installation auxiliary unit, a dynamic stretching-torsion power unit, a test test unit and a static torsion unit. The dynamic stretching-torsion power unit, the test test unit and the static torsion unit are coaxially connected together in sequence. The dynamic stretching-torsion power unit is connected to the test test unit through a compressive torque load transmission short section, and the other end of the test test unit is connected to the static torsion unit through a tensile torque load transmission short section, thereby realizing the mechanical property test of the flexible composite pipe sample under multi-load coupling or single load conditions; the installation auxiliary unit and the dynamic stretching-torsion power unit are arranged in parallel on the installation base, and the installation base is slidably connected to the base guide rail. The installation auxiliary unit is composed of a plurality of flexible composite pipe supports arranged side by side. The installation base slides along the base guide rail to drive the installation auxiliary unit and the test test unit to be in the same straight line, and the flexible composite pipe sample placed by the installation auxiliary unit is pushed to the sample fixing frame of the test test unit.

[0007] The test unit includes a specimen fixing frame, an axial degree of freedom guide rail, a radial degree of freedom guide rail, a vertical degree of freedom guide rail, an upper fixed shaft, a lower movable shaft, a bending radius loading cylinder, a video monitoring system, and a strain monitoring system. The upper end of the bending radius loading cylinder is connected to the lower movable shaft, and the lower movable shaft is located under the flexible composite pipe sample; the strain monitoring system uses a strain gauge attached to the outer surface of the pipe sample to record the strain data of the pipeline under load conditions; the video monitoring system records the morphological deformation of the outer surface of the sample under load conditions during the pipe sample test process through a camera outside the flexible composite pipe sample, and records the morphological deformation of the inside of the pipe under load conditions through an endoscopic camera inside the flexible composite pipe sample.

[0008] The mechanical properties test of flexible composite pipe samples under multi-load coupling or single load conditions in the above scheme includes the mechanical properties test of samples under tension-torsion-internal pressure load conditions, the mechanical properties test of samples under internal pressure-bending load conditions, and the mechanical properties test of samples under single load conditions of tension, torsion, bending and internal pressure.

[0009] In the above scheme, the sample fixing frame is supported at both ends of the flexible composite pipe sample, and the sample fixing frame is composed of two symmetrically arranged fixed sub-frames, the upper end of the fixed sub-frame is an arc-shaped support surface, and the lower end of the fixed sub-frame is installed on the axial freedom fine-tuning guide rail, and the axial freedom fine-tuning guide rail is slidably connected to a pair of radial freedom adjustment guide rails, each radial freedom adjustment guide rail is installed with a vertical freedom guide rail, and a sliding column of a rectangular pipe rack is slidably installed between the two vertical freedom guide rails, and the upper end of the sliding column is slidably connected to the horizontal guide rail to form a rectangular pipe rack, and the rectangular pipe rack frames the flexible composite pipe sample therein, and the inclined pipe rack also frames the flexible composite pipe sample therein, and the inclined pipe rack is fastened together by the upper ends of two inclined supports through the upper fixed shaft, and the lower end of the inclined support is fixed to the base directly below the flexible composite pipe sample, and the bending radius loading top cylinder is arranged on the base and is located between the two inclined pipe racks; multiple camera brackets are arranged on the base.

[0010] In the above scheme, the flexible composite pipe support of the installation auxiliary unit is set on the pipe support base, and the pipe support base is set on the installation base. The installation auxiliary unit moves left and right through the base guide rail to facilitate the lifting of the flexible composite pipe sample; the flexible composite pipe support has a V-shaped structure and is provided with rollers to facilitate the flexible composite pipe sample to be pushed into the test unit.

[0011] In the above scheme, the dynamic stretching-torsion power unit includes a hydraulic cylinder, a first servo motor and a first planetary reducer. The hydraulic cylinder is located on the hydraulic cylinder base, the first servo motor and the first planetary reducer are located on the first servo motor-planetary reducer base, and the hydraulic cylinder base and the first servo motor-planetary reducer base are on the same installation base plane as the pipe support base; the dynamic stretching-torsion power unit and the installation auxiliary unit are synchronously translated left and right to facilitate the flexible composite pipe sample to be pushed into the test unit; the tension generated by the hydraulic cylinder is transmitted to the coupling through the hydraulic connecting rod on the sleeve through the pull rod, and the torsional load generated by the servo motor is slowly released through the planetary reducer, and the torsional load is transmitted to the coupling at the same time; the coupling and the tension and torsional load transfer short section meet through the flange to realize the transmission of tension and torsional loads.

[0012] In the above scheme, the tensile-torsion load transfer short section includes a first male thread short section and a first female thread short section. The first male thread short section meets the first coupling flange through the first male thread short section flange; the first female thread short section meets the flexible composite pipe-like joint flange through the first female thread short section flange; the first female thread short section is also provided with an endoscope camera and a data cable wire hole.

[0013] In the above scheme, the torsional load transfer short section includes a second male thread short section and a second female thread short section. The second male thread short section meets the left test pipe sample joint flange of the flexible composite pipe sample joint; the second female thread short section meets the second coupling flange through the second female thread short section flange; the second male thread short section is also provided with a pressurizing hole, which provides internal pressure load for the flexible composite pipe test pipe sample through the pressurizing hole.

[0014] The static torsion unit in the above scheme includes a servo motor, a planetary reducer, and a servo motor-planetary reducer base. This part of the equipment cannot move left or right and can only provide a bidirectional (or standby) torsional load for the specimen.

[0015] The test method of the multifunctional complex load test equipment for flexible composite pipes is to test the mechanical properties of flexible composite pipe samples under multiple load coupling or single load conditions, specifically including the following tests: (1) Mechanical properties test of samples under tension-torsion-internal pressure load conditions: The evaluation system consists of a dynamic stretch-torsion power unit and a static torsion unit, together with a test unit equipped with a flexible composite pipe sample. The torsional torque generated by the first servo motor and / or the second servo motor is slowly released through the corresponding planetary reducer to provide a torsional load for the flexible composite pipe sample. The tension generated by the hydraulic cylinder is transmitted to the flexible composite pipe sample through the pull rod to provide a tensile load for testing the flexible composite pipe sample. The pressure generated by the high-pressure plunger pump provides an internal pressure load for the flexible composite pipe sample through the pressurized hole. The mechanical behavior of the flexible composite pipe sample under the complex load conditions of tension, torsion and internal pressure is recorded in real time by the video monitoring system and the strain monitoring system. (2) Mechanical properties test of samples under internal pressure-bending load conditions: The flexible composite pipe sample is installed only in the test unit and does not interact with the dynamic tension-torsion power unit or the static torsion unit. The test unit completes the test independently. The bending radius loading cylinder applies an upward pressure load to the flexible composite pipe sample to test the minimum bending radius (or three-point bending) test data. The mechanical behavior of the flexible composite pipe sample under the complex bending and internal pressure loading conditions is recorded in real time by the video monitoring system and the strain monitoring system. (3) Mechanical properties test of samples under single load conditions of tension, torsion, bending and internal pressure: Flexible composite pipe samples are only tested for mechanical properties under single tension, torsion, bending or internal pressure load conditions, and the test results are recorded by a video monitoring system and a strain monitoring system. Beneficial effects

[0016] 1. When testing the mechanical properties of flexible composite pipes under complex loads of tension, torsion, and internal pressure, the present invention generates a tensile load through a hydraulic cylinder and a torque load decelerated by a servo motor through a planetary reducer. The load is then transferred to the flexible composite pipe sample joint flange through a coupling and a compression-torsion load transfer nipple. The pressure load is applied to the interior of the flexible composite pipe sample. The video monitoring system records the visual morphological changes of the pipe sample under complex loads, and the strain monitoring system records the real-time strain data of the pipe sample. When testing under internal pressure-bending loads, the bending radius loading cylinder pushes the lower movable shaft upward, applying an external force load to the flexible composite pipe sample, and the pressure load is applied to the interior of the flexible composite pipe sample. The present invention not only realizes the measurement of the mechanical properties of flexible composite pipes under the above-mentioned complex loads, meeting the complex load simulation test of on-site service conditions, but also can test single compression, tension, torsion, and bending loads. It has a "one machine, multiple functions" function, and significantly reduces the investment and equipment operation and maintenance costs of production enterprises.

[0017] 2. The present invention can simultaneously realize the mechanical property test of flexible composite pipe samples under multi-load coupling and single load conditions, realizing "one machine with multiple functions": (1) Performing mechanical property test of samples under tension-torsion-internal pressure load conditions; (2) Performing mechanical property test of samples under internal pressure-bending load conditions; (3) Performing mechanical property test of samples under single load conditions of tension, torsion, bending and internal pressure.

[0018] 3. The present invention simultaneously records various data and videos of the internal and external appearance of the pipeline, enabling data traceability. The strain monitoring system on the surface of the flexible composite pipe sample and the video surveillance cameras installed outside the test unit simultaneously record the mechanical data of the sample test and provide 360° monitoring and recording of the morphological changes of the flexible composite pipe sample during the test process, providing detailed data support for the verification of the service life prediction data of the flexible composite pipe.

[0019] 4. The test unit of the present invention includes an axial freedom guide rail, a radial freedom guide rail, and a vertical freedom guide rail. By adjusting the axial freedom guide rail, the radial freedom guide rail, and the vertical freedom guide rail, flexible composite pipe samples of different calibers can be tested and evaluated. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 2. This is a general schematic diagram of a multifunctional complex load test equipment for flexible composite pipes according to an embodiment of the present invention; Figure 2 is a schematic diagram of an installation auxiliary unit and a dynamic stretch-torsion power unit according to an embodiment of the present invention; Figure 3 is a schematic diagram of an experimental test unit according to an embodiment of the present invention; Figure 4 is a front view schematic diagram of a test unit according to an embodiment of the present invention; Figure 52. It is a front view schematic diagram of a multifunctional complex load testing device for flexible composite pipes according to an embodiment of the present invention; Figure 6 is a schematic diagram of a static torsion unit according to an embodiment of the present invention; In the figure: 1. Installation auxiliary unit; 11. Flexible composite pipe support; 12. Pipe support base; 13. Roller; 14. Mounting base; 15. Base guide rail; 2. Dynamic stretch-torsion power unit; 211. Hydraulic cylinder base; 212. Hydraulic cylinder; 213. Sleeve; 214. Hydraulic connecting rod; 215. First servo motor; 216. Pull rod; 217. First planetary reducer; 218. First servo motor-planetary reducer base; 219. First coupling; 220, tension and torsion load transfer nipple; 2201, first male thread nipple; 2202, first male thread nipple flange; 2203, first female thread nipple; 2204, first female thread nipple flange; 2205, endoscope camera; 2206, data line lead hole; 3, test unit; 311, flexible composite pipe test tube sample; 3111, left test tube sample joint flange; 3112, right test tube sample joint flange; 312, sample holder; 313, axial freedom fine-tuning guide rail; 314, radial freedom adjustment guide rail; 315, vertical freedom adjustment guide rail; 316, upper Fixed shaft; 317, lower moving shaft; 318, bending radius loading top cylinder; 319, outside pipe video monitoring system; 320, strain monitoring system; 4, static torsion unit; 411, second servo motor-planetary reducer base; 412, second servo motor; 413, second planetary reducer; 414, second coupling; 4141, second coupling flange; 415, compressive torque load transfer short section; 4151, second male thread short section; 4152, second male thread short section flange; 4153, pressurized hole; 4154, second female thread short section; 4155, second female thread short section flange. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings: See Figures 1-6 This flexible composite pipe multifunctional complex load testing equipment includes a dynamic stretching-torsion power unit, a test test unit and a static torsion unit. The dynamic stretching-torsion power unit, the test test unit and the static torsion unit are coaxially connected together in sequence. The dynamic stretching-torsion power unit is connected to the test test unit through a compressive torque load transmission short section, and the other end of the test test unit is connected to the static torsion unit through a tensile torque load transmission short section.

[0022] The installation auxiliary unit is arranged parallel to the dynamic stretch-torsion power unit on the installation base. The installation base is slidably connected to the base rails. The installation auxiliary unit is composed of multiple flexible composite pipe supports arranged side by side. The flexible composite pipe supports are mounted on a pipe support base. The flexible composite pipe supports have a V-shaped structure and are equipped with rollers to facilitate the lifting and pushing of the flexible composite pipe sample into the test unit. The pipe support base is fixed to the installation base. The installation auxiliary unit and the dynamic stretch-torsion power unit are located on the same installation frame. The installation base slides along the base rails, driving the installation auxiliary unit and the test unit to be aligned. The flexible composite pipe sample placed by the installation auxiliary unit can be pushed to the specimen fixing frame of the test unit. The base rails can be moved left and right to facilitate the lifting of the test pipe sample and its installation in the test unit.

[0023] The dynamic tension-torsion power unit includes a hydraulic cylinder base, a hydraulic cylinder, a sleeve, a hydraulic connecting rod, a first servo motor, a tie rod, a first planetary reducer, a first servo motor-planetary reducer base, a tension-torsion short-circuit, and a first coupling. The hydraulic cylinder base and the first servo motor-planetary reducer base are fixed to a mounting frame. The torsional torque generated by the first servo motor is slowly released through the first planetary reducer. The tensile load generated by the hydraulic cylinder is then transmitted through the hydraulic connecting rod, tie rod, and coupling system on the sleeve, via a tension-torsion load transfer sub, to provide a tensile load for testing the flexible composite pipe sample. Specifically, the tension generated by the hydraulic cylinder 212 is transmitted through the hydraulic connecting rod 214 on the sleeve 213, and then through the tie rod 216 to the first coupling 219. The torsional load generated by the first servo motor 215 is slowly released through the first planetary reducer 217, while simultaneously being transferred to the first coupling 219. The first coupling 219 and the tension-torsion load transfer sub 220 meet through a flange, enabling the transmission of tensile and torsional loads. The hydraulic cylinder base 211 and the servo motor-planetary reducer base 218 are located on the same plane as the pipe support base 12 as the mounting base 14. The dynamic stretching-torsion power unit 2 can be translated left and right synchronously with the installation auxiliary unit 1 to facilitate the flexible composite pipe sample 311 to enter the test unit 3.

[0024] The tensile-torsion load transfer pup section 220 includes a first male threaded pup section 2201 and a first female threaded pup section 2203. The first male threaded pup section 2201 meets the first coupling flange 2191 through the first male threaded pup section flange 2202; the first female threaded pup section 2203 meets the flexible composite pipe-like 311 joint flange through the first female threaded pup section flange 2204; the first female threaded pup section 2203 is also provided with an endoscope camera 2205 and a data cable wire hole 2206.

[0025] The test unit includes a specimen holder, an axial freedom guide rail, a radial freedom guide rail, a vertical freedom guide rail, an upper fixed axis, a lower movable axis, a bending radius loading cylinder, a video monitoring system, and a strain monitoring system. The specimen holder is supported at both ends of the flexible composite pipe sample. It consists of two symmetrically arranged fixed sub-frames. The upper ends of the fixed sub-frames are curved support surfaces, and the lower ends of the fixed sub-frames are mounted on axial fine-tuning guide rails. These axial fine-tuning guide rails are slidably connected to a pair of radial adjustment guide rails, each of which is mounted on a vertical guide rail. A sliding column of a rectangular pipe rack is slidably mounted between the two vertical guide rails. The upper ends of the sliding columns slide and connect to horizontal guide rails to form a rectangular pipe rack. The rectangular pipe rack frames the flexible composite pipe sample, and the inclined pipe rack also frames the flexible composite pipe sample. The inclined pipe rack consists of two diagonal braces fastened together at their upper ends by an upper fixed shaft. The lower ends of the diagonal braces are fixed to a base directly below the flexible composite pipe sample. A bending radius loading cylinder is located on the base, between the two diagonal braces. Multiple camera mounts are mounted on the base. By adjusting the axial, radial, and vertical guide rails, pipe samples of varying diameters can be tested and evaluated. The bending radius loading cylinder can be used to apply an upward pressure load to the test pipe sample, which is used to test the minimum bending radius of the pipe sample or obtain three-point bending test data. The video monitoring system uses multiple cameras. The external camera of the pipe sample records the morphological deformation of the sample's outer surface under load conditions during the test. The endoscope camera inside the flexible composite pipe sample records the morphological deformation of the pipe's interior under load conditions. The strain monitoring system uses strain gauges attached to the outer surface of the pipe sample to record the strain data of the pipe under load conditions, facilitating the real-world stress calculation of each part of the sample, which is used to verify the service life prediction data of the flexible composite pipe.

[0026] Adjustment of the status of flexible composite pipe sample 311 in test unit 3: The sample holder 312 is provided with an axial degree of freedom fine-tuning guide rail 313, a radial degree of freedom adjustment guide rail 314 and a vertical degree of freedom adjustment guide rail 315. By adjusting the bearing position, the steel joints of the flexible composite pipe samples 311 of different diameters can be installed on the holder 312.

[0027] Load transfer method for flexible composite pipe sample 311 in test unit 3: The right test tube sample joint flange 3112 at one end of the flexible composite pipe sample 311 meets the first female threaded short section flange 2204 on the tensile-torsion load transfer short section 220 to realize the transmission of compression, tension and torsional loads; the left test tube sample joint flange 3111 at the other end meets the compressive-torsion load transfer short section 415 through the second male threaded short section flange 4152 to realize the torsional load transmission or serve as a backup torsional load transmission carrier.

[0028] Test unit 3 conducts bending deformation test on flexible composite pipe sample 311: The flexible composite pipe test tube sample 311 is fixed between two upper fixed shafts 316 and a lower movable shaft 317. The bending radius loading cylinder 318 applies an upward pressure load to the lower movable shaft 317, pushing the flexible composite pipe test tube sample 311 to generate bending deformation.

[0029] Monitoring of the test process of flexible composite pipe sample 311 in test unit 3: The off-pipe video monitoring system 319 is located outside the flexible composite pipe test tube sample 311, with two groups arranged on the upper part of the flexible composite pipe test tube sample 311, and the other four groups arranged on the left and right sides of the flexible composite pipe test tube sample 311 respectively; the strain monitoring system 320 is arranged on the surface of the flexible composite pipe test tube sample 311 in the form of applied strain gauges; the endoscope camera 2205 is set at one end of the connector of the flexible composite pipe test tube sample 311; various monitoring systems realize 360° monitoring of the test process of the flexible composite pipe test tube sample 311, and real-time record the morphology change data and strain real-time data during the test process.

[0030] The static torsion unit includes a second servo motor, a second planetary reducer, a second servo motor-planetary reducer base, and a second coupling 414. This equipment cannot be moved left or right and can only provide bidirectional (or standby) torsional loads to the specimen. The torsional load transfer nipple 415 includes a second male nipple 4151 and a second female nipple 4154. The second male nipple 4151 connects to the left test pipe flange 3112 of the flexible composite pipe sample 311. The second female nipple 4154 connects to the second coupling flange 4141 via the second female nipple flange 4155. A pressure port 4153 is also provided on the second male nipple 4151 to provide internal pressure loads to the flexible composite pipe test pipe sample 311.

[0031] During the test of the present invention, after the flexible composite pipe sample to be tested is hoisted on the flexible composite pipe support 11, the mounting base 14 is moved to the left as a whole through the base guide rail 15, and the flexible composite pipe sample 311 slides through the roller 13 and enters the test unit 3.

[0032] When the flexible composite pipe sample 311 is about to enter the test unit 3, the radial freedom adjustment guide rail 314 and the vertical freedom adjustment guide rail 315 can be adjusted to move the flexible composite pipe sample 311 to the sample holder 312, and the bearing position can be fine-tuned through the axial freedom fine-tuning guide rail 313 so that the sample holder 312 is supported on the steel joint of the flexible composite pipe sample 311.

[0033] (1) Mechanical properties test of flexible composite pipes under complex load conditions of tension, torsion and internal pressure ①Connection of each part The first female threaded short section flange 2204 at one end of the tension-torsion load transfer short section 220 meets the right test pipe sample joint flange 3112 of the flexible composite pipe sample 311; the first male threaded short section flange 2202 at the other end meets the first coupling flange.

[0034] The second male threaded short section flange 4152 at one end of the compressive torque load transmission short section 415 meets the left test pipe sample joint flange 3111 of the flexible composite pipe sample 311; the second female threaded short section flange 4155 at the other end meets the second coupling flange 4141.

[0035] ②Tensile load loading The hydraulic system is started to enable the hydraulic cylinder 212 to provide a tensile load, and the sleeve 213 transmits the tensile force in sequence through the sleeve 213 - hydraulic connecting rod 214 - pull rod 216 - first coupling 219 - tensile-torsional load transfer short section 220 to the flexible composite pipe test pipe sample 311.

[0036] ③Torsional load loading The torque load generated by the first servo motor 215 in the dynamic tension-torsion power unit 2 is decelerated by the first planetary reducer 217 and transmitted to the flexible composite pipe test tube sample 311 through the first coupling 219-first coupling flange-compression-tension-torsion load transmission short (220). It should be noted that the second servo motor 412 in the static torsion unit 4 is an emergency backup device for generating torque loads. In the event of failure of the first servo motor 215 and the second planetary reducer 217, the static torsion unit 4 can generate the same torque load at the other end of the flexible composite pipe test tube sample 311.

[0037] ④ Internal pressure load The pressure load generated by the electric pressure test pump is provided by the high-pressure hose through the pressurized hole 4153 to provide an internal pressure load for the flexible composite pipe test pipe sample 311.

[0038] ⑤Data monitoring and collection The off-pipe video monitoring system 319 monitors the visual morphological changes of the outer surface of the flexible composite pipe test tube sample 311 under the complex load conditions of tension, torsion and internal pressure; the endoscope monitoring system records the visual morphological changes of the inner surface of the flexible composite pipe test tube sample 311 under the complex load conditions of tension, torsion and internal pressure; the strain monitoring system 320 records the real-time strain data of the flexible composite pipe test tube sample 311 under the complex load conditions of tension, torsion and internal pressure.

[0039] (2) Mechanical properties test of flexible composite pipe under internal pressure-bending load conditions ①Connection of each part The right test pipe sample joint flange 3112 at one end of the flexible composite pipe sample 311 meets the first female threaded short section flange 2204 on the tensile-torsion load transfer short section 220; the left test pipe sample joint flange 3111 at the other end meets the compressive-torsion load transfer short section 415 through the second male threaded short section flange 4152.

[0040] ② Internal pressure load The pressure load generated by the electric pressure test pump is provided by the high-pressure hose through the pressurized hole 4153 to provide an internal pressure load for the flexible composite pipe test pipe sample 311.

[0041] ③ Bending load loading The flexible composite pipe test tube sample 311 is fixed between two upper fixed shafts 316 and a lower movable shaft 317. The bending radius loading cylinder 318 applies an upward pressure load to the lower movable shaft 317, pushing the flexible composite pipe test tube sample 311 to generate bending deformation.

[0042] ④Data monitoring and collection The external video monitoring system 319 monitors the visual morphological changes of the outer surface of the flexible composite pipe test tube sample 311 under the conditions of internal pressure-bending load; the endoscope monitoring system records the visual morphological changes of the inner surface of the flexible composite pipe test tube sample 311 under the conditions of internal pressure-bending load; the strain monitoring system records the real-time strain data of the flexible composite pipe test tube sample 311 under the conditions of internal pressure-bending load.

[0043] (3) Mechanical properties test of flexible composite pipe under single load conditions of tension, torsion, bending and internal pressure: Flexible composite pipe samples are only tested for mechanical properties under single tension, torsion, bending or internal pressure load conditions, and the test results are recorded by a video monitoring system and a strain monitoring system.

Claims

1. A multifunctional complex load testing equipment for flexible composite pipes, characterized by: This multifunctional complex load testing equipment for flexible composite pipes includes an installation auxiliary unit, a dynamic stretching-torsion power unit, a test test unit and a static torsion unit. The dynamic stretching-torsion power unit, the test test unit and the static torsion unit are coaxially connected in sequence. The dynamic stretching-torsion power unit is connected to the test test unit through a compressive torque load transfer short section. The other end of the test test unit is connected to the static torsion unit through a tensile torque load transfer short section, thereby realizing the mechanical property test of the flexible composite pipe sample under multi-load coupling or single load conditions. The installation auxiliary unit and the dynamic stretching-torsion power unit are arranged in parallel on the installation base frame, and the installation base frame is slidably connected to the base frame guide rail. The installation auxiliary unit is composed of a plurality of flexible composite pipe supports arranged side by side. The installation base frame slides along the base frame guide rail to drive the installation auxiliary unit and the test test unit to be in the same straight line, and the flexible composite pipe sample placed on the installation auxiliary unit is pushed to the sample fixing frame of the test test unit. The test unit includes a specimen holder, an axial degree of freedom guide rail, a radial degree of freedom guide rail, a vertical degree of freedom guide rail, an upper fixed shaft, a lower movable shaft, a bending radius loading cylinder, a video monitoring system, and a strain monitoring system. The upper end of the bending radius loading cylinder is connected to the lower movable shaft, and the lower movable shaft is located under the flexible composite pipe sample; the strain monitoring system uses strain gauges attached to the outer surface of the pipe sample to record the strain data of the pipeline under load conditions; the video monitoring system records the morphological deformation of the outer surface of the sample under load conditions during the pipe sample test process through the external camera of the flexible composite pipe sample, and records the morphological deformation of the inside of the pipe under load conditions through the endoscopic camera inside the flexible composite pipe sample.

2. The multifunctional complex load testing equipment for flexible composite pipes according to claim 1 is characterized by: The mechanical property test of the flexible composite pipe sample under multi-load coupling or single load conditions includes the mechanical property test of the sample under tension-torsion-internal pressure load conditions, the mechanical property test of the sample under internal pressure-bending load conditions, and the mechanical property test of the sample under single load conditions of tension, torsion, bending and internal pressure.

3. The multifunctional complex load testing equipment for flexible composite pipes according to claim 2 is characterized by: The sample fixing frame is supported at both ends of the flexible composite pipe sample. The sample fixing frame is composed of two symmetrically arranged fixed sub-frames. The upper end of the fixed sub-frame is an arc-shaped support surface. The lower end of the fixed sub-frame is installed on the axial freedom fine-tuning guide rail. The axial freedom fine-tuning guide rail is slidably connected to a pair of radial freedom adjustment guide rails. Each radial freedom adjustment guide rail is installed with a vertical freedom guide rail. The sliding column of the rectangular pipe rack is slidably installed between the two vertical freedom guide rails. The upper end of the sliding column is slidably connected to the horizontal guide rail to form a rectangular pipe rack. The rectangular pipe rack frames the flexible composite pipe sample. The inclined tube rack also frames the flexible composite tube sample. The inclined tube rack is fastened together by the upper ends of two inclined supports through the upper fixed shaft, and the lower end of the inclined support is fixed on the base directly below the flexible composite tube sample. The bending radius loading top cylinder is set on the base and located between the two inclined tube racks; multiple camera brackets are set on the base.

4. The multifunctional complex load testing equipment for flexible composite pipes according to claim 3 is characterized by: The flexible composite pipe support of the installation auxiliary unit is arranged on the pipe support base, and the pipe support base is arranged on the installation base. The installation auxiliary unit moves left and right through the base guide rail to facilitate the lifting of the flexible composite pipe sample; the flexible composite pipe support has a V-shaped structure and is provided with rollers to facilitate the pushing of the flexible composite pipe sample into the test unit.

5. The multifunctional complex load testing equipment for flexible composite pipes according to claim 4 is characterized by: The dynamic stretching-torsion power unit includes a hydraulic cylinder, a first servo motor and a first planetary reducer. The hydraulic cylinder is located on the hydraulic cylinder base, the first servo motor and the first planetary reducer are located on the first servo motor-planetary reducer base, and the hydraulic cylinder base and the first servo motor-planetary reducer base are on the same installation base plane as the pipe support base; the dynamic stretching-torsion power unit and the installation auxiliary unit are synchronously translated left and right to facilitate the flexible composite pipe sample to be pushed into the test unit; the tension generated by the hydraulic cylinder is transmitted to the coupling through the hydraulic connecting rod on the sleeve through the pull rod, and the torsional load generated by the servo motor is slowly released through the planetary reducer, and the torsional load is transmitted to the coupling at the same time; the coupling and the tension and torsional load transmission short section meet through the flange to realize the transmission of tension and torsional loads.

6. The multifunctional complex load testing equipment for flexible composite pipes according to claim 5 is characterized by: The tensile-torsion load transfer short section includes a first male thread short section and a first female thread short section. The first male thread short section meets the first coupling flange through the first male thread short section flange; the first female thread short section meets the flexible composite pipe-like joint flange through the first female thread short section flange; the first female thread short section is also provided with an endoscope camera and a data cable wire hole.

7. The multifunctional complex load testing equipment for flexible composite pipes according to claim 6, characterized in that: The torsional load transfer short section includes a second male thread short section and a second female thread short section, the second male thread short section meets the left test pipe sample joint flange of the flexible composite pipe sample joint; the second female thread short section meets the second coupling flange through the second female thread short section flange; the second male thread short section is also provided with a pressurizing hole, which provides an internal pressure load for the flexible composite pipe test pipe sample through the pressurizing hole.

8. The multifunctional complex load testing equipment for flexible composite pipes according to claim 7 is characterized by: The static torsion unit includes a servo motor, a planetary reducer and a servo motor-planetary reducer base.

9. A test method for the multifunctional complex load test equipment for flexible composite pipes according to claim 8, characterized in that: The test is a test of the mechanical properties of flexible composite pipe samples under multiple load coupling or single load conditions, specifically including the following tests: (1) Mechanical properties test of samples under tension-torsion-internal pressure load conditions: The evaluation system consists of a dynamic stretch-torsion power unit and a static torsion unit, together with a test unit equipped with a flexible composite pipe sample. The torsional torque generated by the first servo motor and the second servo motor is slowly released through the corresponding planetary reducer to provide a torsional load for the flexible composite pipe sample. The tension generated by the hydraulic cylinder is transmitted to the flexible composite pipe sample through the pull rod to provide a tensile load for testing the flexible composite pipe sample. The pressure generated by the high-pressure plunger pump provides an internal pressure load for the flexible composite pipe sample through the pressurized hole. The mechanical behavior of the flexible composite pipe sample under the complex load conditions of tension, torsion and internal pressure is recorded in real time by the video monitoring system and the strain monitoring system. (2) Mechanical properties test of samples under internal pressure-bending load conditions: The flexible composite pipe sample is only installed in the test unit and is not connected to the dynamic tensile-torsion power unit and the static torsion unit. The bending radius loading cylinder applies an upward pressure load to the flexible composite pipe sample to test the minimum bending radius or three-point bending test data. The mechanical behavior of the flexible composite pipe sample under the complex bending-internal pressure load conditions is recorded in real time by the video monitoring system and the strain monitoring system. (3) Mechanical properties test of samples under single load conditions of tension, torsion, bending and internal pressure: Flexible composite pipe samples are only tested for mechanical properties under single tension, torsion, bending or internal pressure load conditions, and the test results are recorded by a video monitoring system and a strain monitoring system.

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