A prestressed duct test device and method

Abstract

The present invention relates to the technical field of pipeline testing, and in particular provides a prestressed pipeline testing device and method. The prestressed pipeline testing device includes a frame assembly, an adjustment driving assembly, a locking assembly, and a filling and squeezing fixing assembly. The present invention can ensure the degree of fitting of the connecting wrapper and the trapezoidal clamping block to the outside of the metal bellows during inspection, increase the fitting area, thereby improving the fixing tightness, ensuring a more firm connection between the metal bellows and the device, and ensuring the stable progress of the experimental process. At the same time, the filling and squeezing fixing assembly generates internal stress on the inner wall of the metal bellows, so as to simulate the internal state after the metal bellows is poured. At the same time, the fixing effect of the metal bellows is also enhanced, ensuring the accuracy and reliability of the extrusion and tensile test, and more truly detecting the compressive strength of the metal bellows under the actual stress environment, providing important reference data for engineering design and use.

Description

Technical Field

[0001] The present invention relates to the technical field of pipeline testing, and in particular provides a prestressed pipeline testing device and method. Background Art

[0002] The prestressed pipeline is a traditional prestress technology. By arranging prestressed ducts in structures such as concrete beams, slabs, and columns, the bearing capacity and durability of concrete components can be enhanced. It is usually a metal corrugated pipe. The prestressed pipeline generates compressive stress by applying a pre-determined tensile force, thereby offsetting the stress condition of the concrete during use, improving the overall performance and stability of the structure, effectively reducing cracks and deformations in the concrete structure, and extending the service life of the structure. Therefore, before construction, strict strength and other tests should be carried out on the metal corrugated pipe forming the prestressed pipeline to ensure that it can withstand the design requirements of loads and environmental conditions during subsequent pouring, reinforcement, and use, avoid accidental rupture of the pipeline, and ensure the safety of the structure. Summary of the Invention

[0003] Based on this, it is necessary to provide a prestressed pipeline testing device and method to solve at least one technical problem in the background art.

[0004] A prestressed pipeline testing device includes a frame assembly, an adjustment drive assembly, a locking assembly, and a filling and fixing assembly. The frame assembly includes a fixed mounting frame, a test drive frame, and a test adjustment frame. The bottom of the fixed mounting frame is installed on the test bench. Both ends of the outer bottom of the fixed mounting frame are respectively convex with mounting chutes. The inner side of the test drive frame is installed on the outer top of the fixed mounting frame. The outer bottom of the test drive frame is convex with a cylinder mounting plate. The middle of the top surface of the cylinder mounting plate is concave with a first mounting groove. Both ends of the inner side of the test adjustment frame are respectively convex with adjustment sliders. The two adjustment sliders are respectively slidably installed in the two mounting chutes, and adjustment motors are arranged in both adjustment sliders to drive the adjustment sliders to move. The adjustment drive assembly is installed in the first mounting groove. The locking assembly is installed on the outer side of the test adjustment frame. The top of the filling and fixing assembly is installed at the bottom of the adjustment drive assembly, and the filling and fixing assembly is located in the locking assembly.

[0005] As a further improvement of the present invention, the adjustment drive assembly includes two position adjustment cylinders, a cylinder mounting table, and a test cylinder. The two position adjustment cylinders are respectively installed at both ends of the first mounting groove. Both ends of the top surface of the cylinder mounting table are respectively installed in the two output shafts of the two position adjustment cylinders. The middle of the top surface of the cylinder mounting table is concave with a second mounting groove. The test cylinder is installed in the second mounting groove.

[0006] As a further improvement of the present invention, the locking assembly includes a locking installation cylinder body, a sliding fastening cylinder and a plurality of locking elements. The inner side of the locking installation cylinder body is installed on the outer side of the test adjustment frame. The inside of the locking installation cylinder body is hollow to form a locking installation cavity. A mounting cavity is recessed at the top of the inner wall of the locking installation cavity. A plurality of air inlet mounting holes and a plurality of air outlet mounting holes are recessed at intervals along the circumferential direction in the middle of the mounting cavity. And the plurality of air inlet mounting holes are respectively arranged opposite to the plurality of air outlet mounting holes. An air inlet valve is arranged in each air inlet mounting hole, and an air outlet valve is arranged in each air outlet mounting hole. The plurality of air inlet valves and the plurality of air outlet valves are all connected to an external air pump through pipelines. A limiting ring is convexly provided in the middle of the inner wall of the mounting cavity. An inclined triggering annular surface is convexly provided at the bottom of the inner wall of the limiting ring. A sliding mounting cavity is recessed at the bottom of the inner wall of the mounting cavity. A sliding mounting ring is recessed in the middle of the outer wall of the sliding fastening cylinder. The sliding mounting ring is slidably mounted in the sliding mounting cavity. The plurality of locking elements are installed in the mounting cavity at intervals along the circumferential direction. And the bottoms of the plurality of locking elements are all connected to the top of the sliding fastening cylinder.

[0007] As a further improvement of the present invention, a plurality of trapezoidal clamping blocks are convexly provided along the circumferential direction on the top surface of the sliding fastening cylinder. The trapezoidal clamping blocks are made of elastic materials. A first sliding groove is recessed in the middle of the top surface of the trapezoidal clamping block. A second sliding groove is recessed at the bottom of the first sliding groove. A covering forming groove is recessed on the outer side of the top surface of the trapezoidal clamping block. An inclined surface is recessed on the outer side of the top surface of the covering forming groove. The inner side of the trapezoidal clamping block is an arc surface.

[0008] As a further improvement of the present invention, each locking element includes a mounting vertical plate, a test stretcher and a connecting covering device. The outer side of the mounting vertical plate is installed on the inner wall of the mounting cavity. And the height direction of the mounting vertical plate is the same as the height direction of the mounting cavity. An inclined test mounting surface is recessed on the inner side of the bottom surface of the mounting vertical plate. An inclined sliding groove is recessed in the middle of the test mounting surface. An inclined connecting air duct is recessed at the bottom of the inner side of the inclined sliding groove. A connecting air inlet hole and a connecting air outlet hole are recessed in the middle of the outer side of the test mounting surface. The connecting air inlet hole is arranged opposite to the air inlet mounting hole. The air outlet mounting hole is arranged opposite to the connecting air outlet hole. And the connecting air inlet hole and the connecting air outlet hole are both communicated with the inclined connecting air duct. The test stretcher is slidably mounted in the inclined sliding groove through a micro motor. The test stretcher is in the shape of a right trapezoid. A test mounting sliding groove is recessed in the middle of the outer side of the test stretcher. A third sliding groove is recessed at the bottom of the inner side of the test mounting sliding groove. The connecting air duct is recessed at the bottom of the inner side of the third sliding groove. The connecting air duct is communicated with the inclined connecting air duct. The connecting covering device is slidably mounted in the first sliding groove.

[0009] As a further improvement of the present invention, a first limiting slider protrudes from the bottom of the connecting wrapper, and a second limiting slider protrudes from the top of the connecting wrapper. The first limiting slider is slidably installed in the first chute, and the second limiting slider is slidably arranged in the third chute. A micro motor is arranged inside the second limiting slider. A sliding installation hole is recessed in the inner top of the connecting wrapper, and the sliding installation hole communicates with the connecting air duct. A sliding installation pipe is slidably arranged outside the sliding installation hole, and a suction cup is arranged outside the sliding installation pipe. A restoring spring is arranged between the suction cup and the inner side of the connecting wrapper.

[0010] As a further improvement of the present invention, the charging and squeezing fixing assembly includes an installation control column and three charging and squeezing fixing elements. The top of the installation control column is installed in the output shaft of the test cylinder. Three installation plates protrude from the outer wall of the installation control column along the circumferential direction. A strip-shaped chute is recessed in the middle of the side wall of each installation plate. Two first rotation holes are recessed in the top of the side wall of the installation plate along the height direction. First rotation shafts are rotatably arranged in the two first rotation holes, and the three charging and squeezing fixing elements are respectively installed in the three installation plates.

[0011] As a further improvement of the present invention, each charging and squeezing fixing element includes a charging and squeezing adjusting cylinder, a sliding block, two first telescopic rotating shafts, four first connecting rotating shafts, a charger, a cam, and a second telescopic rotating shaft. The bottom end of the charging and squeezing adjusting cylinder is rotatably installed at the bottom of the charging and squeezing fixing element. The inner side of the sliding block is slidably installed in the strip-shaped chute, and the output shaft of the charging and squeezing adjusting cylinder is rotatably connected to the bottom of the sliding block. Second rotating shafts protrude from both ends of the sliding block, and the bottom ends of the two first telescopic rotating shafts are respectively rotatably installed in the two second rotating shafts. One ends of the four first connecting rotating shafts are respectively installed at both ends of the two first rotating shafts. Two third rotating shafts protrude from the inner sides of both ends of the charger along the height direction, and the other ends of the four first connecting rotating shafts are respectively rotatably installed in the four third rotating shafts. A second rotation hole is recessed in the bottom of the charger, and a third rotation shaft is rotatably arranged in the second rotation hole. The middle of the cam is rotatably installed at one end of the third rotation shaft. A fourth rotation hole is recessed in the middle of the side wall of the charger, and a fourth rotation shaft is rotatably arranged in the fourth rotation hole. The top ends of the two first telescopic rotating shafts are respectively installed at both ends of the fourth rotation shaft. One end of the second telescopic rotating shaft is rotatably installed at the tip of the cam, and the other end of the second telescopic rotating shaft is installed at one end of the fourth rotation shaft.

[0012] As a further improvement of the present invention, the inner wall of the filling and extruding device is hollow to form a filling and extruding cavity. In the middle of both ends of the filling and extruding cavity, sliding grooves are recessed. A sliding trigger plate is slidably arranged between the two sliding grooves. At both ends of the inner side of the sliding trigger plate, telescopic columns are respectively protruded. At the outer ends of the telescopic columns, stop arc-shaped pieces are arranged. Between the outer sides of the stop arc-shaped pieces and the inner sides of the sliding trigger plate, compression springs are arranged. In the middle of the inner side of the filling and extruding cavity, a communication groove is recessed. In the middle of the fourth rotating shaft, an eccentric wheel is arranged. The eccentric wheel is located in the communication groove. The outer wall of the eccentric wheel abuts against the inner side of the sliding trigger plate. Along the length direction, a plurality of second strip-shaped sliding grooves are recessed at both ends of the filling and extruding cavity. A fifth rotating shaft is slidably arranged between the two second strip-shaped sliding grooves. At both ends of the fifth rotating shaft, first bearings are respectively arranged. Between the first bearings and the side walls of the second strip-shaped sliding grooves, first springs are arranged. In the middle of the fifth rotating shaft, a first rotating wheel is arranged. The outer wall of the first rotating wheel abuts against the outer side of the sliding trigger plate. In the middle of the third rotating shaft, a second rotating wheel is arranged. At the top of both sides of the filling and extruding cavity, third strip-shaped sliding grooves are respectively recessed. A sixth rotating shaft is slidably arranged between the two third strip-shaped sliding grooves. At both ends of the sixth rotating shaft, second bearings are respectively arranged. Between the second bearings and the bottom surfaces of the third strip-shaped sliding grooves, second springs are arranged. In the middle of the sixth rotating shaft, a third rotating wheel is arranged. A conveyor belt is sleeved between the third rotating wheel, the second rotating wheel and a plurality of first rotating wheels to achieve transmission connection.

[0013] A prestressed duct test method is provided, which is applied to the above-mentioned prestressed duct test device. The test method includes:

[0014] The beneficial effects of the present invention are as follows:

[0015] 1. The present invention uses the locking component to ensure the fixation of the metal corrugated pipe, and can ensure the fitting degree of the connecting covering device and the trapezoidal clamping block to the outside of the metal corrugated pipe, improve the fitting area, and further improve the fixing tightness, ensure the connection between the metal corrugated pipe and the device is more firm, ensure the stable progress of the experiment process, reduce the interference of external factors, and improve the accuracy and reliability of the experimental data.

[0016] 2. The present invention uses the filling and extruding fixing component to generate internal stress on the inner wall of the metal corrugated pipe, thereby simulating the internal state of the metal corrugated pipe after pouring. At the same time, it also enhances the fixing effect of the metal corrugated pipe, ensures the accuracy and reliability of the extrusion and stretching experiment, and more realistically detects the compressive strength of the metal corrugated pipe in the actual stress environment, providing important reference data for engineering design and use.

[0017] 3. When the metal bellows is subjected to a compressive and tensile force exceeding its critical compressive strength, the multi-components of the filling and extrusion fixing component are used to disperse the unloading force, effectively slowing down the impact force on the inside of the filling and extrusion fixing component when the metal bellows collapses and deforms, avoiding damage to the filling and extrusion fixing component caused by excessive impact, improving the durability and stability of the device. At the same time, it can automatically sense and process the collapse and deformation condition of the metal bellows, protecting the safety and integrity of the equipment and experimental data. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a three-dimensional schematic diagram of an embodiment of the present invention.

[0019] Figure 2 It is a three-dimensional schematic diagram of another embodiment of the present invention.

[0020] Figure 3 It is an internal schematic diagram of an embodiment of the present invention.

[0021] Figure 4 It is an internal schematic diagram of the locking component in an embodiment of the present invention.

[0022] Figure 5 It is an internal schematic diagram of the locking component in another embodiment of the present invention.

[0023] Figure 6 It is a three-dimensional schematic diagram of the filling and extrusion fixing component in an embodiment of the present invention.

[0024] Figure 7 It is an internal schematic diagram of the filling and extrusion fixing element in an embodiment of the present invention.

[0025] In the figure:

[0026] 10. Frame assembly; 11. Fixed mounting frame; 111. Mounting chute; 12. Test drive frame; 121. Cylinder mounting plate; 122. First mounting groove; 13. Test adjustment frame; 131. Adjustment slider; 20. Adjustment drive assembly; 21. Position adjustment cylinder; 22. Cylinder mounting table; 23. Test cylinder; 24. Second mounting groove; 30. Locking assembly; 31. Locking mounting cylinder body; 34. Locking mounting cavity; 341. Mounting cavity; 342. Intake mounting hole; 343. Exhaust mounting hole; 344. Intake valve; 345. Exhaust valve; 346. Limiting ring; 347. Triggering annular surface; 348. Sliding mounting cavity; 32. Sliding fastening cylinder; 320. Sliding mounting ring; 321. Trapezoidal clamping block; 322. First chute; 323. Second chute; 324. Wrapping formation groove; 325. Inclined surface; 33. Locking element; 331. Mounting vertical plate; 332. Test stretcher; 333. Connecting wrapper; 334. Test mounting surface; 335. Inclined chute; 336. Inclined connecting air duct; 337. Connecting intake hole; 338. Connecting exhaust hole; 339. Test mounting chute; 330. Connecting air duct; 36. Third chute; 351. First limiting slider; 352. Sliding mounting hole; 353. Sliding mounting pipe; 354. Suction cup; 355. Recovery spring; 350. Second limiting slider; 40. Filling and squeezing fixing assembly; 41. Mounting control column; 411. Mounting plate; 412. Strip chute; 413. First rotation hole; 414. First rotation shaft; 42. Filling and squeezing fixing element; 421. Filling and squeezing adjustment cylinder; 422. Sliding block; 423. First telescopic rotating shaft; 424. First connecting rotating shaft; 425. Filling and squeezer; 426. Cam; 427. Second telescopic rotating shaft; 428. Second rotating shaft; 429. Third rotating shaft; 431. Second rotation hole; 432. Third rotation shaft; 420. Fourth rotation hole; 430. Fourth rotation shaft; 433. Filling and squeezing cavity; 434. Sliding groove; 435. Sliding trigger plate; 436. Telescopic column; 437. Stopping arc piece; 438. Compression spring; 439. Connecting groove; 441. Eccentric wheel; 442. Second strip chute; 443. Fifth rotating shaft; 444. First rotating wheel; 445. Second rotating wheel; 446. Third strip chute; 447. Sixth rotating shaft; 448. Third rotating wheel; 449. Conveyor belt. Detailed implementation manner

[0027] For the convenience of understanding the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that the disclosure of the present invention can be understood more thoroughly and comprehensively.

[0028] In the description of the present invention, it should be noted that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0030] See also Figures 1 to 7 A prestressed pipe test device includes a frame assembly 10, an adjustment drive assembly 20, a locking assembly 30 and an extrusion fixing assembly 40. The frame assembly 10 includes a fixed mounting frame 11, a test drive frame 12 and a test adjustment frame 13. The bottom of the fixed mounting frame 11 is installed on the test bench. Both ends of the outer bottom of the fixed mounting frame 11 are respectively provided with mounting slide grooves 111. The inner side of the test drive frame 12 is installed on the outer top of the fixed mounting frame 11. The outer bottom of the test drive frame 12 is provided with a cylinder mounting plate 121. The top surface of the cylinder mounting plate 121 is provided with a cylinder mounting plate 121. A first mounting groove 122 is recessed in the test adjustment frame 13, and adjustment sliders 131 are convexly provided at both ends of the inner side of the test adjustment frame 13. The two adjustment sliders 131 are respectively slidably installed in the two mounting grooves 111, and adjustment motors are provided in the two adjustment sliders 131 to drive the adjustment sliders 131 to move. The adjustment drive assembly 20 is installed in the first mounting groove 122, the locking assembly 30 is installed on the outer side of the test adjustment frame 13, the top of the squeezing and fixing assembly 40 is installed at the bottom of the adjustment drive assembly 20, and the squeezing and fixing assembly 40 is located in the locking assembly 30.

[0031] The adjustment drive assembly 20 includes two positioning cylinders 21, a cylinder mounting platform 22 and a test cylinder 23. The two positioning cylinders 21 are respectively installed at the two ends of the first mounting groove 122, and the two ends of the top surface of the cylinder mounting platform 22 are respectively installed in the two output shafts of the two positioning cylinders 21. A second mounting groove 24 is recessed in the middle of the top surface of the cylinder mounting platform 22, and the test cylinder 23 is installed in the second mounting groove 24.

[0032] The locking assembly 30 includes a locking mounting cylinder 31, a sliding fastening cylinder 32 and a plurality of locking elements 33. The inner side of the locking mounting cylinder 31 is mounted on the outer side of the test adjustment frame 13. The locking mounting cylinder 31 is hollow inside to form a locking mounting cavity 34. A mounting cavity 341 is recessed on the top of the inner wall of the locking mounting cavity 34. A plurality of air inlet mounting holes 342 and a plurality of air outlet mounting holes 343 are recessed at intervals along the circumferential direction in the middle of the mounting cavity 341. The plurality of air inlet mounting holes 342 are respectively arranged opposite to the plurality of air outlet mounting holes 343. An air inlet valve 344 is arranged in each air inlet mounting hole 342, and a plurality of air outlet mounting holes 343 are arranged in each air outlet mounting hole 343. An exhaust valve 345 is provided, and multiple exhaust valves 344 and multiple exhaust valves 345 are all connected to an external air pump through pipelines. A limiting ring 346 is convexly provided on the middle of the inner wall of the installation cavity 341, and an inclined trigger annular surface 347 is convexly provided on the bottom of the inner wall of the limiting ring 346. A sliding installation cavity 348 is recessed on the bottom of the inner wall of the installation cavity 341, and a sliding installation ring 320 is recessed on the middle of the outer wall of the sliding fastening cylinder 32. The sliding installation ring 320 is slidably installed in the sliding installation cavity 348. Multiple locking elements 33 are installed in the installation cavity 341 at intervals along the circumferential direction, and the bottoms of the multiple locking elements 33 are all connected to the top of the sliding fastening cylinder 32.

[0033] A plurality of trapezoidal clamping blocks 321 are convexly provided along the circumferential direction on the top surface of the sliding fastening cylinder 32, and the trapezoidal clamping blocks 321 are made of elastic material. A first slide groove 322 is recessed in the middle of the top surface of the trapezoidal clamping block 321, and a second slide groove 323 is recessed on the bottom surface of the first slide groove 322. A covering forming groove 324 is recessed on the outer side of the top surface of the trapezoidal clamping block 321, and an inclined surface 325 is recessed on the outer side of the top surface of the covering forming groove 324, and the inner side of the trapezoidal clamping block 321 is an arcuate surface.

[0034] Each locking element 33 includes a mounting vertical plate 331, a test tensioner 332 and a connection cover 333. The outer side of the mounting vertical plate 331 is mounted on the inner wall of the mounting cavity 341, and the height direction of the mounting vertical plate 331 is the same as the height direction of the mounting cavity 341. An inclined test mounting surface 334 is recessed on the inner side of the bottom surface of the mounting vertical plate 331. An inclined slide groove 335 is recessed in the middle of the test mounting surface 334. An inclined connecting airway 336 is recessed at the bottom of the inclined slide groove 335. A connecting air inlet hole 337 and a connecting air outlet hole 338 are recessed in the middle of the outer side of the test mounting surface 334. The connecting air inlet hole 337 is arranged opposite to the air inlet mounting hole 342. The air outlet mounting hole 343 is arranged opposite to the connecting air outlet hole 338, and the connecting air inlet hole 337 and the connecting air outlet hole 338 are both connected to the inclined connecting airway 336. The test stretcher 332 is slidably installed in the inclined slide groove 335 through a micro motor. The test stretcher 332 is a right-angle trapezoid. A test mounting slide groove 339 is recessed in the middle of the outer side of the test stretcher 332. A third slide groove 36 is recessed at the bottom of the inner side of the test mounting slide groove 339. A connecting airway 330 is recessed at the bottom of the inner side of the third slide groove 36. The connecting airway 330 is connected to the inclined connecting airway 336. The connecting cover 333 is slidably installed in the first slide groove 322.

[0035] A first limiting slider 351 is protrudingly provided at the bottom of the connecting cover 333, and a second limiting slider 350 is protrudingly provided at the top of the connecting cover 333. The first limiting slider 351 is slidably installed in the first slide groove 322, and the second limiting slider 350 is slidably installed in the third slide groove 36. A micro motor is arranged in the second limiting slider 350. A sliding mounting hole 352 is recessed at the top of the inner side of the connecting cover 333. The sliding mounting hole 352 is communicated with the connecting airway 330. A sliding mounting tube 353 is slidably provided on the outer side of the sliding mounting hole 352. A suction cup 354 is arranged on the outer side of the sliding mounting tube 353, and a restoring spring 355 is arranged between the suction cup 354 and the inner side of the connecting cover 333.

[0036] The extrusion fixing assembly 40 includes an installation control column 41 and three extrusion fixing elements 42. The top of the installation control column 41 is installed in the output shaft of the test cylinder 23. Three mounting plates 411 are protruding from the outer wall of the installation control column 41 along the circumferential direction. A strip-shaped slide groove 412 is recessed in the middle of the side wall of each mounting plate 411. Two first rotating holes 413 are recessed in the height direction on the top of the side wall of the mounting plate 411. A first rotating shaft 414 is rotatably arranged in the two first rotating holes 413. The three extrusion fixing elements 42 are respectively installed in the three mounting plates 411.

[0037] Each squeezing fixed element 42 includes a squeezing regulating cylinder 421, a sliding block 422, two first telescopic rotating shafts 423, four first connecting rotating shafts 424, a squeezing device 425, a cam 426 and a second telescopic rotating shaft 427. The bottom end of the squeezing regulating cylinder 421 is rotatably mounted on the bottom of the squeezing fixed element 42. The inner side of the sliding block 422 is slidably mounted in the strip slide groove 412. The output shaft of the squeezing regulating cylinder 421 is rotatably connected to the bottom of the sliding block 422. The two ends of the sliding block 422 are respectively convexly provided with a second rotating shaft 428. The bottom ends of the two first telescopic rotating shafts 423 are respectively rotatably mounted in the two second rotating shafts 428. One end of the four first connecting rotating shafts 424 is respectively mounted on the two ends of the two first rotating shafts 414. The two ends of the squeezing device 425 are respectively Two third rotating shafts 429 are respectively protruded on the inner side of the end along the height direction, the other ends of the four first connecting rotating shafts 424 are rotatably installed in the four third rotating shafts 429 respectively, a second rotating hole 431 is recessed at the bottom of the charger 425, the third rotating shaft 432 is rotatably installed in the second rotating hole 431, the middle part of the cam 426 is rotatably installed on one end of the third rotating shaft 432, a fourth rotating hole 420 is recessed in the middle of the side wall of the charger 425, the fourth rotating shaft 430 is rotatably installed in the fourth rotating hole 420, the top ends of the two first telescopic rotating shafts 423 are respectively installed at both ends of the fourth rotating shaft 430, one end of the second telescopic rotating shaft 427 is rotatably installed on the tip of the cam 426, and the other end of the second telescopic rotating shaft 427 is installed on one end of the fourth rotating shaft 430.

[0038] The inner wall of the charger 425 is hollow to form a charging cavity 433. Sliding grooves 434 are recessed in the middle of both ends of the charging cavity 433. A sliding trigger plate 435 is slidably arranged between the two sliding grooves 434. Telescopic columns 436 are respectively protruded at both ends of the inner side of the sliding trigger plate 435. Stopping arc pieces 437 are arranged at the outer ends of the telescopic columns 436. A compression spring 438 is arranged between the outer side of the stopping arc piece 437 and the inner side of the sliding trigger plate 435. A connecting groove 439 is recessed in the middle of the inner side of the charging cavity 433. An eccentric wheel 441 is arranged in the middle of the fourth rotating shaft 430. The eccentric wheel 441 is located in the connecting groove 439. The outer wall of the eccentric wheel 441 is against the inner side of the sliding trigger plate 435. A plurality of second strip sliding grooves 442 are recessed along the length direction at both ends of the charging cavity 433. A fifth rotating shaft 443 is slidably arranged between the two second strip sliding grooves 442. , first bearings are respectively provided at both ends of the fifth rotating shaft 443, a first spring is provided between the first bearing and the side wall of the second strip slide groove 442, a first rotating wheel 444 is provided in the middle of the fifth rotating shaft 443, the outer wall of the first rotating wheel 444 is pressed against the outer side of the sliding trigger plate 435, a second rotating wheel 445 is provided in the middle of the third rotating shaft 432, third strip slide grooves 446 are respectively recessed at the tops of both sides of the filling cavity 433, a sixth rotating shaft 447 is slidably provided between the two third strip slide grooves 446, second bearings are respectively provided at both ends of the sixth rotating shaft 447, a second spring is provided between the second bearing and the bottom surface of the third strip slide groove 446, a third rotating wheel 448 is provided in the middle of the sixth rotating shaft 447, and a conveyor belt 449 is sleeved between the third rotating wheel 448, the second rotating wheel 445 and the plurality of first rotating wheels 444 to realize transmission connection.

[0039] The present invention also provides a prestressed pipe test method, which is applied to the above-mentioned prestressed pipe test device and comprises the following steps:

[0040] Step S1: The bottom end of the metal bellows is fixedly installed in the test bench, and the top end of the metal bellows is arranged in the locking installation cavity 34;

[0041] Step S2: synchronously start the micro motors in the plurality of test stretchers 332 to drive the test stretchers 332 to move upward along the inclined slide slot 335, so that the test stretchers 332 will follow the trapezoidal clamping block 321 of the sliding fastening cylinder 32 pulled by the connecting cover 333 to move upward and inward, so that the inner sides of the connecting cover 333 and the trapezoidal clamping block 321 are attached to the outer wall of the metal bellows;

[0042] Step S3: Synchronously start the two positioning cylinders 21 to drive the cylinder mounting platform 22 to carry the test cylinder 23 and the squeezing and fixing assembly 40 to move downward, so that the squeezing and fixing element 42 moves to the top of the sliding and fastening cylinder 32;

[0043] Step S4: Synchronously start the three filling and extrusion regulating cylinders 421 so that the conveyor belt 449 fully fits the inner wall of the metal bellows;

[0044] Step S5: Start the multiple test stretchers 332 again to test the compressive strength of the metal bellows.

[0045] For example, in one embodiment: the bottom end of the metal bellows is fixedly installed in the test bench, and the top end of the metal bellows is set in the locking installation cavity 34, and then the micro motors in the multiple test stretchers 332 are synchronously started, so that the test stretchers 332 move upward along the inclined slide groove 335, so that the test stretcher 332 will pull the trapezoidal clamping block 321 of the sliding fastening cylinder 32 through the connecting cover 333 to follow the upward movement. Since the test installation surface 334 is an inclined surface and the test stretcher 332 is a right-angled trapezoid, when the test stretcher 332 moves, it will pull the connecting cover 333 to move inward. At the same time, an inclined trigger annular surface is convexly provided on the bottom of the inner wall of the limit ring 346 347, and the outer side of the top surface of the covering forming groove 324 is concavely provided with an inclined surface 325. When the test stretcher 332 is pulled upward, the trapezoidal clamping block 321 made of elastic material will be squeezed and moved inward until the top of the inner side of the trapezoidal clamping block 321 is pressed against the outer wall of the metal bellows. At the same time, the external air pump will start to synchronously deliver gas to multiple air inlet valves 344 to form an extruded airflow. The extruded airflow will enter the connecting airway 330 through the air inlet mounting hole 342 and the inclined connecting airway 336 in sequence. The extruded airflow in the connecting airway 330 will push the connecting wrapper 333 to move inward along the third slide groove 36, so that the sliding mounting tube 353 moves with it, and the suction cup 354 moves with it. The sliding mounting tube 353 moves to the outer wall of the metal bellows, and then, as it continues to move inward, the sliding mounting tube 353 moves outward along the sliding mounting hole 352, and the restoring spring 355 is compressed. Since the sliding mounting hole 352 is connected to the connecting airway 330, part of the extruded air flow enters into the suction cup 354 along the sliding mounting hole 352 and the inner wall cavity of the sliding mounting tube 353, so that the suction cup 354 cannot be completely fastened and adsorbed on the outer wall of the metal bellows until the connecting cover 333 is pushed into the test installation slot 339. Then, the micromotor in the second limiting slider 350 will start, driving the connecting cover 333 to move upward along the third slot 36 inclined inward, thereby pulling the trapezoidal clamping device Block 321 moves further upward and inward, so that the inner side of the connecting cover 333 and the trapezoidal clamping block 321 further fits against the outer wall of the metal bellows, and when the connecting cover 333 moves upward, the sliding mounting hole 352 will follow the upward movement and will no longer be connected to the connecting air channel 330, and the squeezed airflow in the suction cup 354 will disappear, so that the suction cup 354 will fit tightly against the outer wall of the metal bellows under the action of the restoring spring 355, and the squeezed airflow will impact the outer bottom of the trapezoidal clamping block 321 along the connecting air channel 330 through the third slide groove 36 and the test installation slide groove 339, so as to increase the fitting area between the trapezoidal clamping block 321 and the metal bellows, so that the fitting and fixation of the metal bellows is tighter.

[0046] Subsequently, the two adjusting cylinders 21 are synchronously started to drive the cylinder mounting platform 22 to carry the test cylinder 23 and the extrusion fixing assembly 40 downward until the extrusion fixing element 42 moves to the top of the sliding fastening cylinder 32. Subsequently, the extrusion adjusting cylinder 421 is started to drive the sliding block 422 to move upward along the strip slide 412, so that the two first telescopic shafts 423 will rotate and move upward around the two second shafts 428, so that the four first connecting shafts 424 follow and move outward, so that the extruder 425 moves outward until the conveyor belt 449 on the extruder 425 abuts against the metal corrugated plate. At the same time, when the two first telescopic rotating shafts 423 move upward, the fourth rotating shaft 430 will rotate, so that the eccentric wheel 441 will rotate accordingly, and then the sliding trigger plate 435 will move outward along the sliding groove 434, and then synchronously push the multiple first rotating wheels 444 to move outward, so that the conveyor belt 449 is fully fitted to the inner wall of the metal bellows to simulate the internal stress provided by the metal bellows after casting, and then, the micro motors in the multiple test stretchers 332 will be started again to extrude and stretch the metal bellows to test the compressive strength of the metal bellows.

[0047] For example, in one embodiment: when the extrusion and stretching force applied to the metal bellows exceeds the critical point of the compressive strength of the metal bellows, the top end of the metal bellows will collapse and deform inward, thereby impacting the outside of the extruder 425, causing the multiple first rotating wheels 444 to move inward, causing the sliding trigger plate 435 to move inward to rotate the extrusion eccentric wheel 441, causing the fourth rotating shaft 430 to rotate, causing the two first telescopic rotating shafts 423 to extend, and at the same time, two compression springs 438, multiple first springs and second springs are used to relieve pressure. At the same time, the conveyor belt 449 is connected with the third rotating wheel 448, the second rotating wheel 445 and the multiple first rotating wheels 444 with pulleys to relieve pressure on the tensile direction force, so as to reduce the impact of the collapse and deformation of the metal bellows and extend the service life of the extrusion fixing assembly 40.

[0048] Installation process: install the bottom of the fixed mounting frame 11 on the test bench, install the inner side of the test drive frame 12 on the outer top of the fixed mounting frame 11, and slide the two adjusting sliders 131 in the two mounting grooves 111 respectively. The two adjusting cylinders 21 are installed at the two ends of the first mounting groove 122 respectively. The two ends of the top surface of the cylinder mounting platform 22 are installed in the two output shafts of the two adjusting cylinders 21 respectively. The test cylinder 23 is installed in the second mounting groove 24. Install the inner side of the locking mounting cylinder 31 on the outer side of the test adjustment frame 13, slide the sliding mounting ring 320 in the sliding mounting cavity 348, install the outer side of the mounting vertical plate 331 on the inner wall of the mounting cavity 341, and the height direction of the mounting vertical plate 331 is the same as the height direction of the mounting cavity 341. The test stretcher 332 is slidably installed in the inclined groove 335 by a micro motor, and the connecting cover 333 is slidably installed in the first groove 322. The first limit slider 351 slides The first and second limit sliders 350 are slidably arranged in the third slide groove 36. The top of the control column 41 is installed in the output shaft of the test cylinder 23. The bottom end of the charging and extrusion adjusting cylinder 421 is rotatably installed on the bottom of the charging and extrusion fixing element 42. The inner side of the sliding block 422 is slidably installed in the strip slide groove 412, and the output shaft of the charging and extrusion adjusting cylinder 421 is rotatably connected with the bottom of the sliding block 422. The bottom ends of the two first telescopic rotating shafts 423 are rotatably installed in the two second rotating shafts 428 respectively. One ends of the four first connecting rotating shafts 424 are respectively installed at the two ends of the two first rotating shafts 414, and the other ends of the four first connecting rotating shafts 424 are respectively rotatably installed in the four third rotating shafts 429. The middle part of the cam 426 is rotatably installed on one end of the third rotating shaft 432. One end of the second telescopic rotating shaft 427 is rotatably installed on the tip of the cam 426. The other end of the second telescopic rotating shaft 427 is installed on one end of the fourth rotating shaft 430.

[0049] The present invention can achieve:

[0050] 1. The present invention utilizes the locking assembly 30 to ensure the fixation of the metal bellows, and can ensure the degree of fit between the connecting cover 333 and the trapezoidal clamping block 321 and the outside of the metal bellows, thereby increasing the fit area, and further increasing the fixing tightness, ensuring a more secure connection between the metal bellows and the device, ensuring the stability of the experimental process, reducing interference from external factors, and improving the accuracy and reliability of the experimental data.

[0051] 2. The present invention utilizes the extrusion fixing assembly 40 to generate internal stress on the inner wall of the metal bellows, thereby simulating the internal state of the metal bellows after casting. At the same time, it also enhances the fixing effect of the metal bellows, ensures the accuracy and reliability of the extrusion and tensile test, and more realistically detects the compressive strength of the metal bellows under the actual stress environment, providing important reference data for engineering design and use.

[0052] 3. When the metal bellows is subjected to the extrusion and tensile force exceeding the critical point of its compressive strength, the multi-components of the filling and extrusion fixing component 40 are used to disperse the unloading force, effectively slowing down the impact force on the inside of the filling and extrusion fixing component 40 when the metal bellows collapses and deforms, avoiding damage to the filling and extrusion fixing component 40 caused by excessive impact, improving the durability and stability of the device. At the same time, it can automatically sense and process the collapse and deformation condition of the metal bellows, protecting the security and integrity of the equipment and experimental data.

[0053] The above-described embodiments merely represent several embodiments of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A prestressed pipe testing device, characterized in that: The invention comprises a frame assembly (10), an adjustment drive assembly (20), a locking assembly (30) and an extrusion fixing assembly (40), wherein the frame assembly (10) comprises a fixed mounting frame (11), a test drive frame (12) and a test adjustment frame (13), wherein the bottom of the fixed mounting frame (11) is mounted on a test bench, and mounting slide grooves (111) are respectively provided at both ends of the outer bottom of the fixed mounting frame (11), and the inner side of the test drive frame (12) is mounted on the outer top of the fixed mounting frame (11), and a cylinder mounting plate (121) is provided on the outer bottom of the test drive frame (12), and a first recessed portion is provided on the middle of the top surface of the cylinder mounting plate (121). a mounting groove (122), the inner ends of the test adjustment frame (13) are respectively provided with adjustment sliders (131), the two adjustment sliders (131) are respectively slidably mounted in the two mounting slide grooves (111), and the two adjustment sliders (131) are both provided with adjustment motors to drive the adjustment sliders (131) to move, the adjustment drive assembly (20) is mounted in the first mounting groove (122), the locking assembly (30) is mounted on the outer side of the test adjustment frame (13), the top of the squeezing and fixing assembly (40) is mounted on the bottom of the adjustment drive assembly (20), and the squeezing and fixing assembly (40) is located in the locking assembly (30); The locking assembly (30) comprises a locking installation cylinder (31), a sliding fastening cylinder (32) and a plurality of locking elements (33); the inner side of the locking installation cylinder (31) is installed on the outer side of the test adjustment frame (13); the interior of the locking installation cylinder (31) is hollow to form a locking installation cavity (34); a mounting cavity (341) is recessed at the top of the inner wall of the locking installation cavity (34); a plurality of air inlet mounting holes (342) and a plurality of air outlet mounting holes (343) are recessed at intervals along the circumferential direction in the middle of the mounting cavity (341); the plurality of air inlet mounting holes (342) are respectively arranged opposite to the plurality of air outlet mounting holes (343); an air inlet valve (344) is arranged in each air inlet mounting hole (342); and a plurality of air outlet mounting holes (343) are respectively arranged in each air inlet mounting hole (342). An air outlet valve (345) is provided, and a plurality of air inlet valves (344) and a plurality of air outlet valves (345) are all connected to an external air pump through pipelines; a limiting ring (346) is convexly provided at the middle of the inner wall of the installation cavity (341); an inclined trigger annular surface (347) is convexly provided at the bottom of the inner wall of the limiting ring (346); a sliding installation cavity (348) is concavely provided at the bottom of the inner wall of the installation cavity (341); a sliding installation ring (320) is concavely provided at the middle of the outer wall of the sliding fastening cylinder (32); the sliding installation ring (320) is slidably installed in the sliding installation cavity (348); a plurality of locking elements (33) are installed in the installation cavity (341) at intervals along the circumferential direction, and the bottoms of the plurality of locking elements (33) are all connected to the top of the sliding fastening cylinder (32); A plurality of trapezoidal clamping blocks (321) are convexly provided on the top surface of the sliding fastening cylinder (32) in the circumferential direction. The trapezoidal clamping blocks (321) are made of elastic material. A first slide groove (322) is concavely provided in the middle of the top surface of the trapezoidal clamping block (321). A second slide groove (323) is concavely provided on the bottom surface of the first slide groove (322). A covering forming groove (324) is concavely provided on the outer side of the top surface of the trapezoidal clamping block (321). An inclined surface (325) is concavely provided on the outer side of the top surface of the covering forming groove (324). The inner side of the trapezoidal clamping block (321) is an arc-shaped surface. Each locking element (33) includes a mounting vertical plate (331), a test tensioner (332) and a connecting cover (333). The outer side of the mounting vertical plate (331) is mounted on the inner wall of the mounting cavity (341), and the height direction of the mounting vertical plate (331) is the same as the height direction of the mounting cavity (341). An inclined test mounting surface (334) is recessed on the inner side of the bottom surface of the mounting vertical plate (331). An inclined slide groove (335) is recessed in the middle of the test mounting surface (334). An inclined connecting airway (336) is recessed at the bottom of the inner side of the inclined slide groove (335). A connecting air inlet hole (337) and a connecting air outlet hole (338) are recessed in the middle of the outer side of the test mounting surface (334). The connecting air inlet hole (337) and the air inlet mounting hole (342) are arranged opposite to each other. The air outlet installation hole (343) and the connecting air outlet hole (338) are arranged opposite to each other, and the connecting air inlet hole (337) and the connecting air outlet hole (338) are both connected to the inclined connecting air channel (336). The test stretcher (332) is slidably installed in the inclined slide groove (335) through a micro motor. The test stretcher (332) is in a right-angle trapezoidal shape. A test installation slide groove (339) is recessed in the middle of the outer side of the test stretcher (332). A third slide groove (36) is recessed in the inner bottom of the test installation slide groove (339). A connecting air channel (330) is recessed in the inner bottom of the third slide groove (36). The connecting air channel (330) is connected to the inclined connecting air channel (336). The connecting cover (333) is slidably installed in the first slide groove (322). A first limiting slider (351) is convexly provided at the bottom of the connection wrapper (333), a second limiting slider (350) is convexly provided at the top of the connection wrapper (333), the first limiting slider (351) is slidably installed in the first slide groove (322), the second limiting slider (350) is slidably installed in the third slide groove (36), a micro motor is arranged in the second limiting slider (350), a sliding installation hole (352) is concavely provided at the top of the inner side of the connection wrapper (333), the sliding installation hole (352) is connected to the connection airway (330), a sliding installation tube (353) is slidably provided outside the sliding installation hole (352), a suction cup (354) is arranged outside the sliding installation tube (353), and a restoring spring (355) is arranged between the suction cup (354) and the inner side of the connection wrapper (333).

2. The prestressed pipe testing device according to claim 1 is characterized in that: The adjustment drive assembly (20) comprises two positioning cylinders (21), a cylinder mounting platform (22) and a test cylinder (23); the two positioning cylinders (21) are respectively mounted at two ends of a first mounting groove (122); two ends of a top surface of the cylinder mounting platform (22) are respectively mounted in two output shafts of the two positioning cylinders (21); a second mounting groove (24) is recessed in the middle of the top surface of the cylinder mounting platform (22); and the test cylinder (23) is mounted in the second mounting groove (24).

3. The prestressed pipe testing device according to claim 2 is characterized in that: The squeezing and fixing assembly (40) comprises a mounting control column (41) and three squeezing and fixing elements (42). The top of the mounting control column (41) is mounted on the output shaft of the test cylinder (23). Three mounting plates (411) are protrudingly provided on the outer wall of the mounting control column (41) in the circumferential direction. A strip-shaped slide groove (412) is recessed in the middle of the side wall of each mounting plate (411). Two first rotating holes (413) are recessed in the top of the side wall of the mounting plate (411) in the height direction. A first rotating shaft (414) is rotatably provided in each of the two first rotating holes (413). The three squeezing and fixing elements (42) are respectively mounted in the three mounting plates (411).

4. The prestressed pipe testing device according to claim 3 is characterized in that: Each squeezing fixed element (42) comprises a squeezing regulating cylinder (421), a sliding block (422), two first telescopic rotating shafts (423), four first connecting rotating shafts (424), a squeezing device (425), a cam (426) and a second telescopic rotating shaft (427). The bottom end of the squeezing regulating cylinder (421) is rotatably mounted on the bottom of the squeezing fixed element (42). The inner side of the sliding block (422) is slidably mounted in the bar-shaped sliding groove (412). The output shaft of the squeezing regulating cylinder (421) is rotatably connected to the bottom of the sliding block (422). The two ends of the sliding block (422) are respectively protruding with a second rotating shaft (428). The bottom ends of the two first telescopic rotating shafts (423) are respectively rotatably mounted in the two second rotating shafts (428). One end of the four first connecting rotating shafts (424) is respectively mounted on the two ends of the two first rotating shafts (414). The squeezing device (425) is provided with a cam (426) and a second telescopic rotating shaft (427). ) are respectively provided with two third rotating shafts (429) protrudingly on the inner sides of both ends along the height direction, the other ends of the four first connecting rotating shafts (424) are respectively rotatably mounted in the four third rotating shafts (429), a second rotating hole (431) is recessed at the bottom of the filler (425), a third rotating shaft (432) is rotatably mounted in the second rotating hole (431), a middle portion of the cam (426) is rotatably mounted on one end of the third rotating shaft (432), a fourth rotating hole (420) is recessed at the middle portion of the side wall of the filler (425), a fourth rotating shaft (430) is rotatably mounted in the fourth rotating hole (420), the top ends of the two first telescopic rotating shafts (423) are respectively mounted on both ends of the fourth rotating shaft (430), one end of the second telescopic rotating shaft (427) is rotatably mounted on the tip of the cam (426), and the other end of the second telescopic rotating shaft (427) is mounted on one end of the fourth rotating shaft (430).

5. The prestressed pipe testing device according to claim 4 is characterized in that: The inner wall of the charger (425) is hollow to form a charging cavity (433). The middle parts of both ends of the charging cavity (433) are concavely provided with sliding grooves (434). A sliding trigger plate (435) is slidably arranged between the two sliding grooves (434). Telescopic columns (436) are convexly arranged at both ends of the inner side of the sliding trigger plate (435). A stopper arc piece (437) is arranged at the outer end of the stopper arc piece (437). A stopper arc piece (437) is arranged between the outer side of the stopper arc piece (437) and the inner side of the sliding trigger plate (435). A compression spring (438) is provided in the middle of the inner side of the filling cavity (433) with a connecting groove (439), an eccentric wheel (441) is provided in the middle of the fourth rotating shaft (430), the eccentric wheel (441) is located in the connecting groove (439), the outer wall of the eccentric wheel (441) is supported on the inner side of the sliding trigger plate (435), and a plurality of second strip-shaped sliding grooves (442) are provided in the longitudinal direction at both ends of the filling cavity (433), and a fifth rotating shaft is slidably provided between the two second strip-shaped sliding grooves (442). (443), first bearings are respectively arranged at both ends of the fifth rotating shaft (443), a first spring is arranged between the first bearing and the side wall of the second strip-shaped slide groove (442), a first rotating wheel (444) is arranged in the middle of the fifth rotating shaft (443), the outer wall of the first rotating wheel (444) is pressed against the outer side of the sliding trigger plate (435), a second rotating wheel (445) is arranged in the middle of the third rotating shaft (432), and third strip-shaped slide grooves (446) are respectively concavely arranged on the top of both sides of the extrusion cavity (433) ), a sixth rotating shaft (447) is slidably arranged between the two third strip-shaped slide grooves (446), second bearings are respectively arranged at both ends of the sixth rotating shaft (447), a second spring is arranged between the second bearing and the bottom surface of the third strip-shaped slide groove (446), a third rotating wheel (448) is arranged in the middle of the sixth rotating shaft (447), and a conveyor belt (449) is sleeved between the third rotating wheel (448), the second rotating wheel (445) and the plurality of first rotating wheels (444) to achieve transmission connection.

6. A prestressed pipe testing method, applied to the prestressed pipe testing device according to claim 5, characterized in that: The test method includes: Step S1: The bottom end of the metal bellows is fixedly mounted in the test bench, and the top end of the metal bellows is disposed in the locking mounting cavity (34); Step S2: synchronously starting the micro motors in the plurality of test stretchers (332) to drive the test stretchers (332) to move upward along the inclined slide groove (335); the test stretchers (332) pull the trapezoidal clamping block (321) of the sliding fastening cylinder (32) through the connecting wrapper (333), so that the trapezoidal clamping block (321) moves upward and inward, so that the inner sides of the connecting wrapper (333) and the trapezoidal clamping block (321) are attached to the outer wall of the metal bellows; Step S3: Synchronously start the two positioning cylinders (21) to drive the cylinder mounting platform (22) to carry the test cylinder (23) and the filling and fixing assembly (40) to move downward until the filling and fixing element (42) moves to the top of the sliding fastening cylinder (32); Step S4: Synchronously start the three filling and extrusion regulating cylinders (421) so that the conveyor belt (449) fully fits against the inner wall of the metal bellows; Step S5: starting the plurality of test stretchers (332) again to perform a compressive strength test on the metal bellows.

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