Large-diameter bimetal composite pipe stretching and bending combined load test method

Abstract

The invention relates to the field of bimetal composite pipe load tests, in particular to a large-diameter bimetal composite pipe stretching and bending combined load test method. The large-diameter bimetal composite pipe stretching and bending combined load test method comprises the following steps: respectively carrying out a stretching test and a bending test on a large-diameter bimetal composite pipe by using a stretching and bending test machine to provide internal support, and arranging a vertical hydraulic tensile machine and a transverse hydraulic tensile machine, the upper mechanical clamp and the lower mechanical clamp are used for clamping the two ends of the bimetal composite pipe respectively, the upper inner supporting rod and the lower inner supporting rod jointly provide inner supporting for the bimetal composite pipe, the large-area collapse phenomenon is avoided, and the stretching or bending test limit value of the bimetal composite pipe is effectively measured. The technical defects that the bimetal composite pipe has a large-area collapse phenomenon when being stretched due to lack of an inner support in an actual working condition, and a test limit value cannot be obtained are overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of bimetallic composite pipe load test, in particular to a large-diameter bimetallic composite pipe tensile and bending combined load test method. BACKGROUND

[0002] The large-diameter bimetallic composite pipe is a new type of pipe material which combines a metal with good corrosion resistance and a high-strength metal. This composite structure not only retains the advantages of the two materials, but also improves the overall performance of the pipe, making it have a wide application prospect in the fields of marine engineering and oil transportation. Tensile test and bending test are important methods for evaluating the mechanical properties of materials. For large-diameter bimetallic composite pipes, tensile test is mainly used to determine the tensile strength, yield strength and ductility of the base pipe and the overlaying layer, and the purpose of bending test is to determine the bending performance of the material. However, when existing equipment tests bimetallic composite pipes, there is a large area of collapse when the pipes are subjected to tension or bending due to the lack of internal support inside the pipes. Therefore, it is not possible to simulate the test when the bimetallic composite pipe is filled with internal support under real application conditions, and thus the test limit value of the bimetallic composite pipe cannot be obtained. SUMMARY

[0003] In order to overcome the shortcomings of the bimetallic composite pipe lacking internal support in real application conditions, resulting in a large area of collapse when subjected to tension or bending and failing to obtain the test limit value, the present application provides a large-diameter bimetallic composite pipe tensile and bending combined load test method.

[0004] The technical scheme is as follows: a large-diameter bimetallic composite pipe tensile and bending combined load test method, which uses a tensile and bending testing machine to perform tensile test and bending test on the large-diameter bimetallic composite pipe. In the tensile test, internal support is used to avoid collapse, thereby accurately determining the tensile test limit value. A tensile and bending testing machine includes a test table, a vertical hydraulic tension machine, a horizontal hydraulic tension machine, an upper fixed block, an upper mechanical clamp, an inner lining block, an upper internal support rod, a lower fixed block, a lower mechanical clamp, a sleeve, and a lower internal support rod. The test table is connected with the vertical hydraulic tension machine which applies upward tensile load. The vertical lifting part of the vertical hydraulic tension machine is connected with the horizontal hydraulic tension machine which applies horizontal bending load. The horizontal moving part of the horizontal hydraulic tension machine is connected with the upper fixed block. The upper fixed block is connected with the upper mechanical clamp. The inner lining block is fixedly connected in the upper fixed block. The upper internal support rod is connected in the inner lining block to provide upper internal support. The upper internal support rod penetrates downward through the upper mechanical clamp. The test table is connected with the lower fixed block. The lower fixed block is connected with the lower mechanical clamp. The lower fixed block is connected with the sleeve. The sleeve is connected with the lower internal support rod to provide lower internal support. The lower internal support rod penetrates upward through the lower mechanical clamp.

[0005] As a further preferred solution, an adjusting thread structure is provided on the outer surface of the upper inner support rod; the upper inner support rod is screwed to the inner liner block through the adjusting thread structure.

[0006] As a further preferred solution, the sleeve is slidably connected to the lower fixed block; a height adjustment screw is rotatably connected inside the test bench; the height adjustment screw is screwed to the sleeve; and an adjustment motor is installed on the fixed plate inside the test bench to drive the height adjustment screw to rotate.

[0007] As a further preferred embodiment, a hollow cavity structure is provided in the upper inner support rod; a liquid inlet pipe structure connected to the hollow cavity structure is provided on the upper inner support rod; a plurality of drainage thread structures are provided on the outer surface of the lower inner support rod; a liquid collecting trough structure connected to the drainage thread structure is provided on the sleeve; a vertical channel structure connected to the liquid collecting trough structure is provided in the sleeve; and a collection pipe is inserted into the vertical channel structure of the sleeve.

[0008] As a further preferred solution, a sealing ring for sealing the lower port of the bimetallic composite pipe is fixedly connected in the lower mechanical clamp.

[0009] As a further preferred solution, a suction pump is installed on the fixed plate connected to the regulating motor; the inlet end of the suction pump is connected to the lower outlet end of the collecting pipe.

[0010] As a further preferred solution, the upper end of the lower inner support rod is provided with a sealing protrusion structure adapted to the hollow cavity structure of the upper inner support rod.

[0011] As a further preferred solution, the upper inner support rod is provided with a plurality of liquid outlet structures connected to the hollow cavity structure.

[0012] As a further preferred solution, the outer surface of the upper inner support rod is provided with guide thread structures corresponding to the number of the liquid outlet hole structures, and the guide thread structures are connected to the corresponding liquid outlet hole structures.

[0013] As a further preferred solution, a temperature sensor for performing temperature testing on the bimetallic composite pipe is installed in the lower mechanical clamp.

[0014] Beneficial effects: the large-diameter bimetal composite pipe tensile and bending composite load test method of the application is to use a tensile and bending testing machine to provide internal support for large-diameter bimetal composite pipe to carry out tensile test and bending test respectively, the tensile and bending testing machine provided by the application is provided with a vertical hydraulic tension machine and a horizontal hydraulic tension machine, the two ends of the bimetal composite pipe are clamped by the upper mechanical clamp and the lower mechanical clamp respectively, in the tensile test, the upper inner support rod cooperates with the lower inner support rod to provide complete internal support for the bimetal composite pipe, so as to avoid large-area tensile collapse phenomenon and accurately obtain the tensile test limit value of the bimetal composite pipe, in the bending test, the upper inner support rod cooperates with the lower inner support rod to provide internal support with a cavity for the bimetal composite pipe, the cavity is aligned with the bending area of the bimetal composite pipe, so as to avoid large-area bending collapse phenomenon and effectively measure the bending test limit value of the bimetal composite pipe; the technical defects that the bimetal composite pipe cannot obtain the test limit value due to the lack of internal support in the actual working condition and the existence of large-area collapse phenomenon when subjected to tensile or bending are overcome. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a perspective view of a tensile and bending testing machine of the application; Figure 2 It is a perspective view of a vertical hydraulic tension machine and a horizontal hydraulic tension machine of the tensile and bending testing machine of the application; Figure 3 It is a perspective view of an upper inner support rod of the tensile and bending testing machine of the application; Figure 4 It is a perspective view of a lower fixed block of the tensile and bending testing machine of the application; Figure 5 It is a perspective view of a lower mechanical clamp of the tensile and bending testing machine of the application; Figure 6 It is a sectional perspective view of a lower fixed block of the tensile and bending testing machine of the application; Figure 7 It is a partial sectional perspective view of a sleeve of the tensile and bending testing machine of the application; Figure 8 It is a partial perspective view of a height-adjusting screw rod of the tensile and bending testing machine of the application.

[0016] Fig. 1 is a test bench, 21 is a vertical hydraulic tension machine, 22 is a horizontal hydraulic tension machine, 31 is an upper fixing block, 32 is an upper mechanical clamp, 33 is an inner lining block, 34 is an upper inner support rod, 3401 is an adjusting screw structure, 3402 is a hollow cavity structure, 3403 is a liquid inlet pipe structure, 3404 is a liquid outlet hole structure, 3405 is a flow guide screw structure, 41 is a lower fixing block, 42 is a lower mechanical clamp, 43 is a sleeve, 4301 is a liquid collecting groove structure, 4302 is a vertical channel structure, 44 is a height adjusting screw rod, 45 is an adjusting motor, 46 is a lower inner support rod, 4601 is a drainage screw structure, 4602 is a plug bump structure, 47 is a collecting pipe, 48 is a sealing ring, 49 is a suction pump, and 5 is a temperature sensor. DETAILED DESCRIPTION

[0017] The technical solutions of the present application are further described below in combination with the drawings.

[0018] In Example 1, a large-diameter bimetal composite pipe tensile and bending composite load test method is provided by using a tensile and bending testing machine to provide internal support for the large-diameter bimetal composite pipe to perform tensile test and bending test.

[0019] As shown in Figures 1-8 , the tensile and bending testing machine of the present embodiment comprises a test bench 1, a vertical hydraulic tension machine 21, a horizontal hydraulic tension machine 22, an upper fixing block 31, an upper mechanical clamp 32, an inner lining block 33, an upper inner support rod 34, a lower fixing block 41, a lower mechanical clamp 42, a sleeve 43, and a lower inner support rod 46; the test bench 1 is connected with the vertical hydraulic tension machine 21, the vertical hydraulic tension machine 21 can apply an upward tensile load to the bimetal composite pipe; the vertical lifting part of the vertical hydraulic tension machine 21 is connected with the horizontal hydraulic tension machine 22, the horizontal hydraulic tension machine 22 can apply a horizontal bending load to the bimetal composite pipe; the horizontal moving part of the horizontal hydraulic tension machine 22 is connected with the upper fixing block 31; the upper fixing block 31 is connected with the upper mechanical clamp 32; the inner lining block 33 is fixedly connected in the upper fixing block 31; the upper inner support rod 34 is connected in the inner lining block 33; the upper inner support rod 34 penetrates downward through the upper mechanical clamp 32; the test bench 1 is connected with the lower fixing block 41; the lower fixing block 41 is connected with the lower mechanical clamp 42; the lower fixing block 41 is connected with the sleeve 43; the sleeve 43 is connected with the lower inner support rod 46; the lower inner support rod 46 penetrates upward through the lower mechanical clamp 42; the upper mechanical clamp 32 cooperates with the lower mechanical clamp 42 to clamp the two ends of the bimetal composite pipe; the upper inner support rod 34 cooperates with the lower inner support rod 46 to provide internal support for the bimetal composite pipe.

[0020] As shown in Figure 3As shown, the upper inner support rod 34 is provided with an adjusting threaded structure 3401 on the outer surface; the upper inner support rod 34 is screwed with the inner lining block 33 through the adjusting threaded structure 3401; the operator manually rotates the upper inner support rod 34 to drive it to move along the inner lining block 33 in the upward and downward directions, so as to realize the manual adjustment of the extension length of the upper inner support rod 34.

[0021] As shown, Figures 6-8 The sleeve 43 is slidingly connected with the lower fixed block 41; the test bench 1 is rotatably connected with a height-adjusting screw rod 44; the height-adjusting screw rod 44 is screwed with the sleeve 43; a fixed plate in the test bench 1 is provided with an adjusting motor 45; the output shaft of the adjusting motor 45 is fixedly connected with the height-adjusting screw rod 44; the adjusting motor 45 drives the height-adjusting screw rod 44 to rotate, and at the same time, the height-adjusting screw rod 44 drives the sleeve 43 to move along the lower fixed block 41 in the upward and downward directions, so as to realize the adjustment work of the sleeve 43 driving the lower inner support rod 46 to extend from the lower mechanical clamp 42.

[0022] The tensile test method of the tensile and bending testing machine of the embodiment is as follows.

[0023] First, the operator controls the vertical hydraulic tension machine 21 to drive the upper fixed block 31 and the upper mechanical clamp 32 connected with the horizontal hydraulic tension machine 22 to move downward, clamps the upper end and the lower end of the bimetallic composite pipe between the upper mechanical clamp 32 and the lower mechanical clamp 42 respectively, and inserts the upper inner support rod 34 into the upper side of the bimetallic composite pipe and the lower fixed block 41 into the lower side of the bimetallic composite pipe, then the adjusting motor 45 drives the height-adjusting screw rod 44 to rotate, the height-adjusting screw rod 44 drives the sleeve 43 and the lower inner support rod 46 connected with the sleeve 43 to move upward, so that the upper end of the lower inner support rod 46 tightly abuts against the upper inner support rod 34, so that the upper inner support rod 34 and the lower inner support rod 46 jointly provide complete inner support to the bimetallic composite pipe, then the vertical hydraulic tension machine 21 pulls the upper mechanical clamp 32 to apply an upward tensile load to the bimetallic composite pipe, and at the same time, the upper inner support rod 34 and the lower inner support rod 46 jointly provide inner support to the bimetallic composite pipe, so as to avoid the large-area tensile collapse of the bimetallic composite pipe during the tensile process, so that each tensile area of the bimetallic composite pipe maintains a complete tubular structure for tensile test, and the tensile test limit value of the bimetallic composite pipe is effectively measured.

[0024] The bending test method of the tensile and bending testing machine of the embodiment is as follows.

[0025] First, the operator adjusts the length of the upper inner support rod 34 from the upper mechanical clamp 32, and then controls the vertical hydraulic tensioner 21 to drive the upper fixed block 31 and the upper mechanical clamp 32 connected by the horizontal hydraulic tensioner 22 to move downward, so that the upper end and the lower end of the bimetallic composite pipe are clamped between the upper mechanical clamp 32 and the lower mechanical clamp 42, and the upper inner support rod 34 is inserted into the upper side of the bimetallic composite pipe, and the lower fixed block 41 is inserted into the lower side of the bimetallic composite pipe. Then, adjust the motor 45 to drive the height adjustment screw rod 44 to rotate, and the height adjustment screw rod 44 drives the sleeve 43 and the lower inner support rod 46 connected thereto to move upward, so that the upper end of the lower inner support rod 46 moves upward to approach the upper inner support rod 34, but the lower inner support rod 46 does not tightly adhere to the upper inner support rod 34, so that the lower inner support rod 46 and the upper inner support rod 34 have a short distance cavity structure inside the bimetallic composite pipe, and the cavity structure is aligned with the area of the bimetallic composite pipe to be tested for bending. In this way, the upper inner support rod 34 and the lower inner support rod 46 jointly provide internal support for the area of the bimetallic composite pipe that does not need to be tested for bending, and then the horizontal hydraulic tensioner 22 drives the upper fixed block 31 to drive the upper mechanical clamp 32 to apply a bending load to the right of the bimetallic composite pipe. At this time, the upper inner support rod 34 and the lower inner support rod 46 jointly provide internal support for the area of the bimetallic composite pipe that does not need to be tested for bending, and only allow the area of the bimetallic composite pipe to be tested for bending to appear bending deformation under the action of the bending load to the right, so as to avoid the phenomenon of large area bending collapse of the bimetallic composite pipe during bending, and effectively measure the bending test limit value of the bimetallic composite pipe.

[0026] The tensile and bending composite test method of the tensile and bending testing machine of the embodiment is as shown below.

[0027] First, the operator adjusts the length of the upper inner support rod 34 extending from the upper mechanical clamp 32, and then controls the vertical hydraulic tensile machine 21 to drive the upper fixed block 31 and the upper mechanical clamp 32 connected to the horizontal hydraulic tensile machine 22 to move downward, clamping the upper and lower ends of the bimetallic composite pipe between the upper mechanical clamp 32 and the lower mechanical clamp 42 respectively, and inserting the upper inner support rod 34 into the upper side of the bimetallic composite pipe, and inserting the lower fixed block 41 into the lower side of the bimetallic composite pipe. Then, the adjustment motor 45 drives the height adjustment screw rod 44 to rotate, and the height adjustment screw rod 44 drives the sleeve 43 and the lower inner support rod 46 connected to it to move upward, so that the upper end of the lower inner support rod 46 is upward and close to the upper inner support rod 34, but the lower inner support rod 46 is not tightly attached to the upper inner support rod 34, so that the lower inner support rod 46 and the upper inner support rod 34 are in the bimetallic composite pipe. A short-distance cavity structure is left in the inner part, and the cavity structure is aligned with the area of ​​the bimetallic composite pipe to be subjected to the bending test, so that the upper inner support rod 34 and the lower inner support rod 46 can jointly provide internal support for the area of ​​the bimetallic composite pipe that does not need to be subjected to the bending test, and then the vertical hydraulic tensile machine 21 pulls the upper mechanical clamp 32 to apply an upward tensile load to the bimetallic composite pipe. At the same time, the horizontal hydraulic tensile machine 22 pushes the upper fixed block 31 to drive the upper mechanical clamp 32 to apply a rightward bending load to the bimetallic composite pipe. At this time, the upper inner support rod 34 and the lower inner support rod 46 jointly provide internal support for the area of ​​the bimetallic composite pipe that does not need to be subjected to the bending test. The bimetallic composite pipe is subjected to the upward tensile load and the rightward bending load at the same time and produces corresponding deformation, thereby effectively measuring the tensile and bending composite test limit values ​​of the bimetallic composite pipe.

[0028] Example 2, based on the above example 1, Figures 1-8 As shown, a hollow cavity structure 3402 is provided in the upper inner support rod 34 of this embodiment; a liquid inlet pipe structure 3403 connected to the hollow cavity structure 3402 is provided at the upper end of the upper inner support rod 34, and the liquid inlet pipe structure 3403 is externally connected to the output port of the heat transfer oil delivery device; a plurality of drainage thread structures 4601 are provided on the outer surface of the lower inner support rod 46; a liquid collecting tank structure 4301 connected to the lower outlet end of all the drainage thread structures 4601 is provided on the sleeve 43; A vertical channel structure 4302 connected to the liquid collecting tank structure 4301 is provided in the cylinder 43; a collecting pipe 47 is inserted into the vertical channel structure 4302 of the sleeve 43; a sealing ring 48 is fixedly connected to the lower mechanical clamp 42 to seal the lower end of the bimetallic composite pipe; a suction pump 49 is installed on the fixed plate connected to the regulating motor 45; the inlet end of the suction pump 49 is connected to the lower outlet end of the collecting pipe 47; the outlet end of the suction pump 49 is externally connected to the reflux port of the heat transfer oil conveying equipment.

[0029] In this embodiment, when the bimetallic composite pipe is clamped between the lower mechanical clamp 42 and the upper mechanical clamp 32, the lower end of the bimetallic composite pipe is tightly sealed against the sealing ring 48, the lower inner support rod 46 and the upper inner support rod 34 are both inserted into the interior of the bimetallic composite pipe, and the lower inner support rod 46 and the upper inner support rod 34 are not in close contact with each other, leaving a long distance cavity structure between the lower inner support rod 46 and the upper inner support rod 34 inside the bimetallic composite pipe. Then, the external heat conducting oil conveying device continuously conveys heat conducting oil at a specified temperature into the hollow cavity structure 3402 through the liquid inlet pipe structure 3403 of the upper inner support rod 34. The heat conducting oil flowing out of the hollow cavity structure 3402 enters the cavity structure between the lower inner support rod 46 and the upper inner support rod 34 inside the bimetallic composite pipe. The heat conducting oil then flows along the drainage thread structure 4601 of the lower inner support rod 46, through the inner wall of the bimetallic composite pipe, and into the liquid collection groove structure 4301 of the sleeve 43. Finally, the suction pump 49 sucks the heat conducting oil in the liquid collection groove structure 4301 through the collection pipe 47 and conveys it back to the external heat conducting oil conveying device, achieving the adjustment of the temperature of the bimetallic composite pipe to a specified temperature by the continuous flow of heat conducting oil through the cavity structure inside the bimetallic composite pipe. In this way, the bimetallic composite pipe can be subjected to corresponding tensile testing or bending testing under different specified temperature conditions. The temperature sensor 5 is installed in the lower mechanical clamp 42 and continuously monitors the temperature of the bimetallic composite pipe to determine whether the bimetallic composite pipe is in a specified temperature condition.

[0030] In embodiment 3, based on the above-mentioned embodiment 2, as shown in the figure, the upper end of the lower inner support rod 46 of this embodiment is provided with a plug block structure 4602 adapted to the lower outlet end of the hollow cavity structure 3402 of the upper inner support rod 34. Figures 1-8

[0031] ​In the present embodiment, after the lower inner support rod 46 and the upper inner support rod 34 are brought close to each other and tightly attached, the plug block structure 4602 at the upper end of the lower inner support rod 46 is blocked at the outlet end of the hollow cavity structure 3402 of the upper inner support rod 34, and the lower outlet end of the flow guide thread structure 3405 is aligned with the upper inlet end of the flow guide thread structure 4601. At this time, the heat conducting oil in the upper inner support rod 34 cannot flow out from the lower outlet end of the hollow cavity structure 3402, and the heat conducting oil in the upper inner support rod 34 flows out from the liquid outlet hole structure 3404 into the flow guide thread structure 3405, and then flows along the flow guide thread structure 3405 to the corresponding flow guide thread structure 4601. The heat conducting oil can continue to flow along the flow guide thread structure 3405 and the flow guide thread structure 4601 through the inner wall of the bimetallic composite pipe, and the heat conducting oil continuously flowing through the inner wall of the bimetallic composite pipe can continuously heat and conduct the bimetallic composite pipe, so that the bimetallic composite pipe can continuously be in the specified temperature condition to complete the tensile test work. In addition, the heat conducting oil flowing through the flow guide thread structure 3405 and the flow guide thread structure 4601 can also act as a lubricant to provide lubrication for the inner wall of the bimetallic composite pipe, reducing the resistance of the upper inner support rod 34 and the lower inner support rod 46 moving in the bimetallic composite pipe. Not only can the upper inner support rod 34 and the lower inner support rod 46 be more easily inserted and pulled, but also can reduce the wear of the upper inner support rod 34 and the lower inner support rod 46 when moving in the bimetallic composite pipe.

[0032] The technical principles of the embodiments of the present application are described above in combination with specific embodiments. These descriptions are only to explain the principles of the embodiments of the present application, and cannot be interpreted in any way as a limitation on the protection scope of the embodiments of the present application. Based on the explanations here, those skilled in the art can think of other specific embodiments of the embodiments of the present application without creative labor, and these embodiments will fall within the protection scope of the embodiments of the present application.

Claims

1. A method for testing the combined tensile and bending loads of large-diameter bimetallic composite pipes, characterized by: This method uses a tensile and bending testing machine to perform tensile tests and bending tests on large-diameter bimetallic composite pipes. During the tensile test, internal supports are used to prevent collapse, thereby accurately determining the tensile test limit value. A tensile and bending testing machine comprises a test bench (1), a vertical hydraulic tensile machine (21), a transverse hydraulic tensile machine (22), an upper fixed block (31), an upper mechanical clamp (32), an inner lining block (33), an upper inner support rod (34), a lower fixed block (41), a lower mechanical clamp (42), a sleeve (43) and a lower inner support rod (46); the test bench (1) is connected with a vertical hydraulic tensile machine (21) for applying an upward tensile load; the vertical lifting component of the vertical hydraulic tensile machine (21) is connected with a transverse hydraulic tensile machine (22) for applying a transverse bending load; the transverse moving component of the transverse hydraulic tensile machine (22) is connected with the ... A fixed block (31); an upper mechanical clamp (32) is connected to the upper fixed block (31); an inner lining block (33) is fixedly connected to the upper fixed block (31); an upper inner support rod (34) for providing upper inner support is connected to the inner lining block (33); the upper inner support rod (34) passes through the upper mechanical clamp (32) downward; a lower fixed block (41) is connected to the test bench (1); a lower mechanical clamp (42) is connected to the lower fixed block (41); a sleeve (43) is connected to the lower fixed block (41); a lower inner support rod (46) for providing lower inner support is connected to the sleeve (43); the lower inner support rod (46) passes through the lower mechanical clamp (42) upward.

2. A method for testing a large-diameter bimetallic composite pipe under combined tensile and bending loads according to claim 1, characterized in that: An adjusting thread structure (3401) is provided on the outer surface of the upper inner support rod (34); the upper inner support rod (34) is screwed to the inner lining block (33) via the adjusting thread structure (3401).

3. The method for testing a large-diameter bimetallic composite pipe under combined tensile and bending loads according to claim 1, characterized in that: The sleeve (43) is slidably connected to the lower fixed block (41); a height adjustment screw rod (44) is rotatably connected in the test bench (1); the height adjustment screw rod (44) is screwed to the sleeve (43); and an adjusting motor (45) for driving the height adjustment screw rod (44) to rotate is installed on the fixed plate in the test bench (1).

4. The method for testing a large-diameter bimetallic composite pipe under combined tensile and bending loads according to claim 1, wherein: A hollow cavity structure (3402) is provided in the upper inner support rod (34); a liquid inlet pipe structure (3403) connected to the hollow cavity structure (3402) is provided on the upper inner support rod (34); a plurality of drainage thread structures (4601) are provided on the outer surface of the lower inner support rod (46); a liquid collecting trough structure (4301) connected to the drainage thread structure (4601) is provided on the sleeve (43); a vertical channel structure (4302) connected to the liquid collecting trough structure (4301) is provided in the sleeve (43); and a collecting pipe (47) is inserted into the vertical channel structure (4302) of the sleeve (43).

5. A tensile and bending combined load test method for large-diameter bimetallic composite pipes according to claim 4, characterized in that: A sealing ring (48) for sealing the lower end of the bimetallic composite pipe is fixedly connected to the lower mechanical clamp (42).

6. A tensile and bending combined load test method for large-diameter bimetallic composite pipes according to claim 4, characterized in that: A suction pump (49) is mounted on a fixed plate connected to the regulating motor (45); the inlet end of the suction pump (49) is connected to the lower outlet end of the collecting pipe (47).

7. The method for testing a large-diameter bimetallic composite pipe under combined tensile and bending loads according to claim 4, characterized in that: The upper end of the lower inner support rod (46) is provided with a sealing protrusion structure (4602) adapted to the hollow cavity structure (3402) of the upper inner support rod (34).

8. The method for testing a large-diameter bimetallic composite pipe under combined tensile and bending loads according to claim 4, wherein: The upper inner support rod (34) is provided with a plurality of liquid outlet structures (3404) connected to the hollow cavity structure (3402).

9. A tensile and bending combined load test method for large-diameter bimetallic composite pipes according to claim 8, characterized in that: The outer surface of the upper inner support rod (34) is provided with guide thread structures (3405) corresponding in number to the liquid outlet hole structures (3404), and the guide thread structures (3405) are connected to the corresponding liquid outlet hole structures (3404).

10. A tensile and bending combined load test method for a large-diameter bimetallic composite pipe according to any one of claims 4 to 9, characterized in that: A temperature sensor (5) for performing temperature testing on the bimetallic composite pipe is installed in the lower mechanical clamp (42).

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