General fixture for irregular clamped end blade high temperature high cycle fatigue test

Abstract

This invention relates to the field of aero-engine testing technology and discloses a universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped blades. The fixture consists of a cylindrical main structure and a clamping structure. Finite element simulation design ensures that the resonant frequency is close to the blade's resonant frequency, amplifying the vibration stress. The fixture is made of high-temperature alloys and single-crystal high-temperature alloys, and the fasteners are high-temperature resistant hexagonal bolts, the diameter and number of which can be adjusted according to the blade shape. The fixture is easy to operate and suitable for high-temperature and room-temperature vibration fatigue testing. In one embodiment, the fixture is equipped with a mounting platform and a locking system to achieve automatic positioning, fixing, and convenient removal of the blade clamping end, improving testing efficiency. In another embodiment, the hydraulic fixture system adopts a central cylinder and single-cylinder design, using hydraulic fluid to clamp the blade. Different hydraulic fluid media can be selected according to the testing environment, such as liquid silicone at 800 degrees Celsius.

Description

Technical Field

[0001] This invention relates to the field of aero-engine testing, and more specifically to a universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped blades sampled from aero-engine impellers. Background Technology

[0002] Vibration fatigue testing of blades is a crucial test for evaluating the fatigue characteristics of key components in aero-engines. High-temperature, high-cycle vibration fatigue testing is a method that closely approximates the high-temperature and vibration environment of an engine, and its development has been rapid in recent years. Test pieces need to be batch-tested for individual blade vibration fatigue, typically in quantities of 15 or more. During testing, the blades must be held very securely by clamps to apply the vibration stress from the vibration table to the blade clamping end. Extensive testing has shown that high-frequency, large-scale testing conditions require the blade clamping end to have surface contact or multi-point compression contact.

[0003] As test specimens, the blades on aero engines vary in shape depending on their location. Test specimens specially made for testing can be designed with simple, regular-shaped clamping ends for easy installation. However, the compressor blades, low-pressure turbine blades, and high-pressure turbine blades on the engine have tenon clamping ends. The blades are machined as individual parts and can be directly removed from the impeller disk assembly. Although their shapes are irregular, each blade has the same shape, and only one set of fixtures needs to be designed.

[0004] For blade testing on integrally machined impellers (such as radial impellers), the blades and mounting structure are machined as a single unit, making it impossible to directly remove individual blades. Sampling requires destroying the impeller and using mechanical cutting technology to cut it into individual blades, which are then tested as individual rotor blades. Due to the dimensional differences and large-angle shape distortions among the blades, the shape of the clamping end of each blade is inconsistent. Measuring the shape of each blade and designing a separate fixture would be extremely time- and economically costly. Therefore, there is a great need for highly versatile fixtures that can adapt to the irregular shapes of blade clamping ends in high-temperature, high-cycle vibration fatigue testing.

[0005] Therefore, we propose a universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped blades to address the problems mentioned above. Summary of the Invention

[0006] The purpose of this invention is to provide a universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped blades, in order to solve the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] A general-purpose fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped blades includes a main structure connected to a resonant table and a clamping structure for fixing the irregular workpiece. The bottom of the main structure has a through hole for mounting and connecting with the resonant table. The clamping structure is mounted on the cylindrical main structure, and the upper part of the main structure has a mounting groove for placing the blade clamping end. A mounting platform supporting the clamping structure is fixedly connected above the mounting groove of the main structure. The clamping structure includes multiple independently adjustable clamping fasteners and a drive unit for pushing the fasteners to clamp. The side of the mounting platform near the mounting groove has a guide hole for the fasteners to pass through. The drive unit pushes the multiple independently adjustable clamping fasteners through the guide hole to clamp the irregular workpiece inside the mounting groove.

[0009] Preferably, the diameter and height of the main structure are obtained by finite element simulation calculation based on the vibration frequency and vibration magnitude of the blade test piece. When the resonant frequency of the main structure matches the resonant frequency of the blade, the main structure amplifies the vibration from the blade through the clamping structure.

[0010] Preferably, the main structure uses different types of metal materials depending on the test temperature.

[0011] Preferably, the fastener is a sliding toothed rod, the driving part is a high-temperature resistant spring fixedly connected to the sliding toothed rod, the guide hole is a sliding hole, multiple sliding holes are provided and distributed in a matrix, and a control room is opened inside the installation platform, and a locking component for locking the position of the sliding toothed rod is installed inside the control room;

[0012] The sliding toothed rod is divided into a smooth section and a flat toothed section. The smooth section of the sliding toothed rod is sleeved inside the sliding hole, and the flat toothed section of the sliding toothed rod is located inside the control room. The high-temperature resistant spring is located inside the control room. Each sliding toothed rod is independently equipped with a high-temperature resistant spring, which pushes the sliding toothed rod towards the blade clamping end mounting groove.

[0013] The locking assembly includes a positioning clamp and a first threaded post. The positioning clamp includes a first clamp and a second clamp. Both the first clamp and the second clamp are provided with flat tooth grooves that mate with the flat tooth section surface of the sliding tooth rod. The first clamp and the second clamp are symmetrically arranged inside the control room. The surface of the first threaded post includes two symmetrically arranged threads. The first clamp and the second clamp are respectively installed outside the two symmetrically arranged threads.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0015] First, the fixture of this invention, through finite element simulation calculations, ensures that the resonant frequency of the fixture is close to the resonant frequency of the blade, effectively amplifying vibration stress and improving test efficiency and accuracy. The fixture uses different types of metal materials to adapt to different temperature environments, including high-temperature alloys and single-crystal high-temperature alloys, suitable for both high-temperature and room-temperature vibration fatigue tests. The clamping structure uses independently adjustable fasteners, whose diameter and number can be adjusted according to the shape of the blade clamping end, adapting to irregularly shaped blades. The fixture is easy to install and use; different blade shapes can be adapted by changing the fasteners, reducing test costs. Furthermore, a high-temperature anti-seize lubricant is applied to the fasteners to prevent them from "seizing" with the threaded holes at high temperatures, facilitating removal after the test. This fixture has a simple structure, strong versatility, and is suitable for vibration fatigue tests on blades of different shapes and temperature ranges, significantly reducing test costs. By changing the fasteners rather than the entire fixture, different blade shapes can be adapted, saving on fixture processing costs.

[0016] Secondly, this invention, through the cooperation of sliding toothed rods and high-temperature resistant springs, enables the fixture to automatically position and clamp according to the irregular surface shape of the blade clamping end, simplifying the operation steps and improving work efficiency. The fixture adopts an elastic clamping method to pre-fix the irregular blade clamping end. Simply insert the blade clamping end into the mounting slot, and multiple sliding toothed rods automatically match and clamp with the irregular blade clamping end. The drive column drives multiple sets of locking components to rotate synchronously, achieving synchronous locking of multiple sliding toothed rods. This reduces the workload of multi-point positioning and clamping operations, facilitates the rapid installation and disassembly of experimental workpieces, and is convenient and quick to operate. The installation and disassembly of the blade clamping end can be completed by rotating the drive column, saving test preparation time. Through the engagement of the annular toothed ring of the elastic positioning sleeve with the annular toothed groove of the mounting platform, and the fixed connection between the inner cylinder and the internal hexagonal nut of the drive column, the fixture has high stability, preventing the irregular clamping end blade from loosening during high-temperature and high-cycle vibration fatigue tests.

[0017] Third, the fixture of Embodiment 3 of the present invention can adapt to high-temperature testing environments ranging from 200 degrees to 800 degrees Celsius. Using liquid silicone at 800 degrees Celsius as the hydraulic fluid medium ensures stability and reliability under extreme high-temperature conditions. Through a central cylinder and a hydraulic system of multiple single cylinders, it can precisely control the clamping force at the blade clamping end. The push rod in the hydraulic system can automatically adjust the clamping force according to the irregular shape of the blade, achieving stable high-pressure clamping. It is suitable for testing blades of different strengths, ensuring the stability and safety of the blade during the testing process. The pressure transmitter on the hydraulic pipe can monitor the pressure of the hydraulic system in real time and perform precise control through the control module, ensuring that the pressure remains stable at the set value, improving the accuracy and safety of the test. Furthermore, the electric hydraulic pump controls the quantity and delivery pressure of the hydraulic fluid, making operation simple and easy to automate, reducing manual intervention and improving testing efficiency.

[0018] Fourth, the fixture in Embodiment 4 of this invention adopts high-temperature resistant materials and structural design, ensuring safety during the test process. The fixture uses hydraulic fluid as a pressure source, and the pressure regulating plate is moved by the central threaded column to achieve mechanical pressurization. This method is not only direct in pressurization, but also suitable for reducing the fluidity requirements of the hydraulic fluid, making it suitable for high-temperature and high-cycle vibration fatigue tests. The clamping and releasing operations are achieved by the turntable driving the central threaded column to rotate, simplifying the operation process. The mechanical pressurization of the fixture avoids the use of complex hydraulic systems. Furthermore, the use of liquid metal alloys, such as Sn-Bi alloy, as the hydraulic fluid, which remains liquid even in the 800°C test environment, thereby extending the service life of the fixture. During the high-temperature and high-cycle vibration fatigue test, the fixture can maintain a stable clamping state, improving the reliability of the test data. Furthermore, the fixture, through the combination design of the push rod and the jaws, can form multi-point contact at the blade clamping end, thereby enhancing the friction and improving the clamping stability of the fixture at the blade clamping end. This addresses the more complex stress distribution on the surface of irregularly shaped blades. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall external structure of Embodiment 1 of the present invention;

[0020] Figure 2 This is a top view of the structure of Embodiment 1 of the present invention;

[0021] Figure 3 This is a side view of the structure of Embodiment 1 of the present invention;

[0022] Figure 4 This is a front view diagram of Embodiment 1 of the present invention.

[0023] Figure 5 This is a schematic diagram of the overall external structure of Embodiment 2 of the present invention;

[0024] Figure 6 This is a schematic diagram of the connection structure between the clamping structure and the mounting platform in Embodiment 2 of the present invention;

[0025] Figure 7 This is a cross-sectional view of the elastic positioning sleeve according to Embodiment 2 of the present invention;

[0026] Figure 8 This is a schematic diagram of the overall external structure of Embodiment 3 of the present invention;

[0027] Figure 9 This is a schematic cross-sectional view of the main structure of Embodiment 3 of the present invention;

[0028] Figure 10 This is a schematic diagram of the overall side cross-sectional structure of Embodiment 3 of the present invention;

[0029] Figure 11This is a schematic diagram of the overall external structure of Embodiment 4 of the present invention;

[0030] Figure 12 This is a cross-sectional structural diagram of Embodiment 4 of the present invention.

[0031] The components are as follows: 1. Main structure; 2. Through hole; 3. Mounting groove; 4. Mounting platform; 5. Screw; 6. Drive nut; 7. Threaded hole; 8. Sliding rack; 9. High-temperature resistant spring; 10. First threaded column; 11. First clamping plate; 12. Second clamping plate; 13. Flat tooth groove; 14. Drive column; 16. Inner cylinder; 17. Outer cylinder; 18. Annular toothed ring; 19. Annular tooth groove; 20. Central cylinder; 21. Inlet valve; 22. Single cylinder; 23. Diverter port; 24. Push rod; 25. Piston; 26. Sliding hole; 27. Hydraulic pipe; 28. Pressure regulating plate; 29. ​​Central threaded column; 30. Turntable; 31. Air chamber; 32. Fluid chamber. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1:

[0034] Please see Figure 1-4 The present invention provides the following technical solution:

[0035] A general-purpose fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped blades includes a main structure 1 connected to a resonance table and a clamping structure for fixing the irregularly clamped blades. The main structure 1 is a cylindrical structure with through holes 2 distributed along the circumference of the bottom. The through holes 2 are used to directly connect to the moving coil of the vibration table or to the cooling base on the moving coil. The clamping structure is installed on the cylindrical main structure 1. The diameter and height of the main structure 1 are obtained by finite element simulation calculation based on the vibration frequency and vibration magnitude of the blade test piece. The resonant frequency of the structure is as close as possible to the resonant frequency of the blade to facilitate the amplification of the vibration stress of the vibration table.

[0036] Finite element method (FEM) simulation refers to the use of computer simulation analysis technology to predict the structural response under stress through mathematical models. In fixture design, FEM can simulate the behavior of blades during vibration tests, including stress distribution and vibration response. The vibration frequency and magnitude of the blade specimen refer to the expected vibration frequency and intensity during the test. Vibration frequency refers to the number of vibrations per second, while vibration magnitude describes the amplitude or energy of the vibration. The structural resonant frequency refers to the vibration mode of the fixture itself at a specific frequency. When the resonant frequency of the fixture matches the resonant frequency of the blade, the fixture amplifies the vibration from the blade, thereby improving the efficiency and accuracy of the test.

[0037] The diameter and height of main structure 1 need to be calculated using finite element method (FEM) simulation based on the vibration frequency and magnitude of the blade specimen. The aim is to ensure that the resonant frequency of the fixture is as close as possible to the resonant frequency of the blade. The advantages are: when the resonant frequency of the fixture is close to that of the blade, the fixture acts like an amplifier, amplifying the blade's vibration, making the vibration stress applied by the vibration table more concentrated and significant; amplifying the vibration stress makes the blade more prone to fatigue failure, thus allowing for faster testing of the blade's fatigue life. Through simulation calculations, designers can optimize the fixture's structural design, ensuring stable operation under the expected vibration conditions while reducing unnecessary vibration and noise.

[0038] The clamping structure includes multiple matrix-style independently adjustable fasteners; the upper part of the main structure 1 has a horizontal mounting groove 3, which is U-shaped and used for placing the blade clamping end; the main structure 1 has a matrix of threaded holes 7 above the U-shaped groove for installing fasteners.

[0039] During high-temperature testing, mounting slot 3 is placed inside the heating chamber. The U-shaped slot is 10cm larger than the thickness of the blade clamping end cut from the blade, which facilitates the adjustment of the fastener's upper and lower position.

[0040] Furthermore, the diameter of the through hole 2 is determined according to the specifications of the selected fastener, and should be slightly larger than the outer diameter of the fastener (e.g., 1mm), usually 11mm or 13mm, etc.

[0041] Furthermore, depending on the test temperature, different types of metal materials are used for the main structure 1. When the temperature is below 800°C, the high-temperature alloy GH5188 is preferred; when the temperature is above 800°C, single-crystal high-temperature alloys, such as DD432 and DD426 nickel-based high-temperature alloys, are preferred. DD432 and DD426 alloys have very high melting points, usually above 1300°C, which can maintain their performance in extreme high-temperature environments and maintain the stability of their shape and size during long-term high-temperature operation.

[0042] Furthermore, the main structure 1 has a mounting platform 4 above the U-shaped groove for placing fasteners. The mounting platform 4 is an integrally formed structure with the main structure 1. The mounting platform 4 has multiple rows of threaded holes 7 for fastener installation. The spacing of the threaded holes 7 should ensure that the bolt heads of the fasteners do not interfere with each other.

[0043] The fastener is a high-temperature resistant hexagonal socket head cap screw, which includes a threaded shank 5 and an integrally formed hexagonal socket head cap 6. The hexagonal socket head cap 6 is rotated by an Allen wrench, which drives the shank 5 to rotate.

[0044] Furthermore, different materials are selected for the internal hex bolts depending on the test temperature. For temperatures below 400℃, 310S high-temperature alloy is selected; for temperatures below 800℃, high-temperature alloy GH5188 is preferred; and for temperatures above 800℃, single-crystal high-temperature alloys, such as DD432 and DD426 nickel-based high-temperature alloys, are preferred.

[0045] Furthermore, the end of the screw 5 of the socket head cap screw is used to clamp the blade clamping end. In order to prevent the protruding part from damaging the blade clamping end, the end of the screw 5 is machined into a plane perpendicular to the axis of the screw 5.

[0046] Furthermore, the diameter of the fasteners should be matched according to the shape of the clamping end. If the blade clamping end is relatively flat, the fastener diameter can be larger, such as M16 or M12. If the blade clamping end is more complex, the fastener diameter needs to be smaller and the fasteners should be arranged more densely so that more fasteners can be used for clamping and better adapt to the irregular shape of the clamping end.

[0047] The operation method of this fixture is as follows: First, pass the high-temperature resistant fastener through the through hole 2 and fix the main structure 1 on the moving ring of the vibration table or the cooling base on the moving ring; then, put the blade clamping end into the U-shaped groove, and adjust the front-back and left-right positions of the blade clamping end to maximize the number of threaded holes 7 above the blade clamping end; finally, tighten all the fasteners that can contact the surface of the blade clamping end; then remove the fasteners that are not needed.

[0048] When clamping the blade, tighten the fasteners one by one. By using different bolt heights, it can adapt to the irregular shape of the blade clamping end. When tightening, use a torque wrench to apply torque to the fasteners to ensure that the force is uniform at each fastener clamping point.

[0049] To prevent the fastener from "seizing" with the threaded hole 7 at high temperatures, making it difficult to remove after the test, a commercially available high-temperature thread anti-seizing agent, also known as a high-temperature anti-seizing lubricant, such as YBS-8231 anti-seizing agent, should be applied to the fastener screw 5 before tightening. This agent can be used at temperatures below 1400℃.

[0050] The fixture of this invention can be used not only at high temperatures, but also for vibration fatigue testing at room temperature.

[0051] When testing the irregularly shaped blade clamping ends cut from the impeller, simply changing the position and number of fasteners can perfectly adapt to the shape of the blade clamping ends. This method has the advantages of high efficiency and saving on fixture processing costs, strong versatility, and significantly reduced testing costs.

[0052] The present invention provides a universal fixture for high-temperature and high-cycle vibration fatigue testing of irregularly clamped blades. It has a simple structure, is adaptable to high-temperature vibration fatigue testing environments, and can be used in high-temperature environments with different temperature ranges by changing the processing materials. By adjusting the reusable fasteners, it can be adapted to different clamping end shapes of the blades to be tested. It is easy to install and use, and simplifies the blade vibration fatigue testing process.

[0053] Example 2:

[0054] Please see Figure 5-7 Furthermore, in conjunction with Example 1, it is obtained that,

[0055] The fastener mounting platform 4 has several sliding holes 26 at its bottom. A sliding toothed rod 8 is slidably sleeved inside the sliding holes 26. The fastener mounting platform 4 has a control chamber inside, and a locking component for locking the position of the sliding toothed rod 8 is installed inside the control chamber.

[0056] The sliding toothed rod 8 is divided into a smooth section and a flat tooth section. The flat tooth section of the sliding toothed rod 8 is composed of several linearly equidistantly distributed annular teeth, and the annular teeth coincide with the axis of the sliding toothed rod 8.

[0057] The smooth section of the sliding toothed rod 8 is sleeved inside the sliding hole 26. The flat toothed section of the sliding toothed rod 8 is located inside the control room. A flat cap is fixedly connected to one end of the sliding toothed rod 8 inside the control room. A high-temperature resistant spring 9 is fixedly connected to the upper part of the flat cap. The other end of the high-temperature resistant spring 9 is fixedly connected to the inner wall of the control room. Each sliding toothed rod 8 is individually equipped with a high-temperature resistant spring 9. The high-temperature resistant spring 9 pushes the sliding toothed rod 8 towards the blade clamping end mounting groove 3, so that the sliding toothed rod 8 is elastically clamped to the irregular shaped surface of the blade clamping end.

[0058] Furthermore, the locking assembly includes a positioning clamp and a first threaded post 10. The positioning clamp includes a first clamp 11 and a second clamp 12. The first clamp 11 is a strip-shaped clamp, and its side near the sliding toothed rod 8 is provided in a flat tooth groove 13. The flat tooth groove 13 is adapted to engage with the surface of the flat tooth section of the sliding toothed rod 8. Multiple flat tooth grooves 13 can be provided according to the distribution of the sliding toothed rod 8.

[0059] The second clamping plate 12 has the same shape as the first clamping plate 11. The first clamping plate 11 and the second clamping plate 12 are symmetrically arranged. The ends of the first clamping plate 11 and the second clamping plate 12 are slidably connected to the interior of the control room. The surface thread of the first threaded column 10 adopts a segmented design, which includes two symmetrically arranged threaded sections. The first clamping plate 11 and the second clamping plate 12 are respectively installed on the outside of the two symmetrically arranged threaded sections and connected by threaded engagement. Thus, when the first threaded column 10 is rotated, the first clamping plate 11 and the second clamping plate 12 are driven by the first threaded column 10. Under movement, they can move closer or further apart; when the first clamping plate 11 and the second clamping plate 12 are close together, the flat tooth groove 13 engages with the flat tooth section of the sliding tooth rod 8, making it impossible for the sliding tooth rod 8 to slide in the axial direction, and the smooth section of the sliding tooth rod 8 is tightly fitted with the inside of the sliding hole 26, restricting the swaying of the sliding tooth rod 8 in the horizontal direction, thereby further locking the sliding tooth rod 8 that elastically clamps the blade clamping end, realizing the fixed clamping of the irregular shaped surface of the blade clamping end, and preventing the blade clamping end from swaying in the vibration fatigue test.

[0060] Based on the number and position distribution of the sliding toothed rods 8, multiple sets of locking components can be set up. The multiple sets of locking components are arranged in parallel. The first threaded post 10 of two adjacent locking components are welded and fixed together. The first threaded post 10 at both ends is rotatably connected to the mounting platform 4 of the fastener.

[0061] The fastener mounting platform 4 is rotatably connected to a drive column 14 on the side away from the mounting groove 3. The drive column 14 is fixedly connected to the end of the first threaded column 10 near it. The drive column 14 can drive the first threaded column 10 to rotate. Multiple first threaded columns 10 are fixedly connected to achieve synchronous rotation.

[0062] The end of the drive column 14 away from the first threaded column 10 is integrally formed with an internal hexagonal nut. The outer periphery of the internal hexagonal nut is hexagonal prism, and its outer periphery can also be square prism. An elastic positioning sleeve is sleeved on the outside of the drive column 14. The elastic positioning sleeve includes an inner cylinder 16 and an outer cylinder 17. The outer periphery of the inner cylinder 16 is hexagonal prism, and the outer periphery of the outer cylinder 17 is cylindrical. The inner shape of the outer cylinder 17 is the same as the outer shape of the inner cylinder 16, and the inner dimension of the outer cylinder 17 is larger than the outer dimension of the inner cylinder 16.

[0063] The outer cylinder 17 is slidably sleeved on the outside of the inner cylinder 16. A high-temperature spring 9 is located between the inner cylinder 16 and the outer cylinder 17. The high-temperature spring 9 pushes the inner cylinder 16 and the outer cylinder 17 to extend outward and contract when subjected to radial pressure. The hexagonal nut of the drive column 14 is fixedly connected to the inner cylinder 16. An annular toothed ring 18 is provided on the side of the outer cylinder 17 near the mounting platform 4. An annular toothed groove 19 matching the annular toothed ring 18 is provided on the mounting platform 4 near the outer cylinder 17.

[0064] When it is necessary to lock the sliding toothed rod 8 that elastically clamps the blade clamping end, the drive column 14 is rotated using an Allen wrench and an Allen nut. The drive column 14 drives multiple first threaded columns 10 to rotate synchronously. As described above, the first clamping plate 11 and the second clamping plate 12 are brought closer together, so that the flat tooth groove 13 engages with the flat tooth section of the sliding toothed rod 8, locking the sliding toothed rod 8 after elastic clamping, thus fixing it to the irregular shape surface of the blade clamping end. In this structure, through the cooperation of the sliding toothed rod 8 and the high-temperature resistant spring 9, several sliding toothed rods 8 can automatically adjust according to the shape of the irregular shape surface of the blade clamping end. The positioning and clamping mechanism is convenient and quick to operate. By rotating the drive column 14, multiple locking components are engaged and fixed to the sliding toothed rod 8. In this operation, only the drive column 14 needs to be rotated to achieve synchronous locking of several sliding toothed rods 8, which greatly reduces the workload of multi-point positioning and clamping operations. When removing the blade clamping end, simply rotate the drive column 14 in the opposite direction to release the locking of the sliding toothed rod 8. At the same time, the sliding toothed rod 8 still elastically clamps the blade clamping end to prevent the blade from falling. The blade clamping end can be manually pulled out to complete the removal of the blade clamping end. This solution improves the working efficiency of high-temperature and high-cycle vibration fatigue testing of blades with irregular clamping ends.

[0065] Furthermore, the drive column 14 is locked by engaging the elastic positioning sleeve with the annular toothed groove 19 of the mounting platform 4. The elastic positioning sleeve works as follows: when the drive column 14 needs to be rotated, the outer cylinder 17 is pulled towards the inner cylinder 16, and the annular toothed ring 18 of the outer cylinder 17 separates from the annular toothed groove 19. At this time, the elastic positioning sleeve rotates with the drive column 14. When the drive column 14 has finished rotating and needs to be fixed, the outer cylinder 17 is released. Under the pushing action of the internal high-temperature resistant spring 9, the annular toothed ring 18 of the outer cylinder 17 engages with the annular toothed groove 19, so the outer cylinder 17 cannot rotate. The outer cylinder 17 and the inner cylinder 16 are hexagonal prisms, and they cannot rotate relative to each other. The inner cylinder 16 is fixedly connected to the internal hexagonal nut of the drive column 14, so the drive column cannot rotate, thus completing the locking of the drive column 14. This further enhances the stability of the clamping fixture and prevents the irregular clamping end blades from loosening during high-temperature and high-cycle vibration fatigue tests.

[0066] Example 3:

[0067] Please see Figure 8-10 In conjunction with Embodiment 2, the difference from Embodiment 2 is that the fastener mounting platform 4 is provided with a central cylinder 20 inside, the interior of the central cylinder 20 is rectangular, and the upper end of the central cylinder 20 is provided with a liquid inlet valve 21.

[0068] Multiple single cylinders 22 are fixedly connected to one side of the central cylinder body 20 near the blade clamping end mounting groove 3. The single cylinder 22 is cylindrical, and a flow divider 23 is provided between the single cylinder 22 and the central cylinder body 20.

[0069] A push rod 24 is slidably connected inside the single cylinder 22. A piston 25 is provided at one end of the push rod 24 near the central cylinder body 20. The piston 25 and the inner wall of the single cylinder 22 are slidably sealed.

[0070] The inlet valve 21 of the central cylinder 20 is connected to a high-temperature resistant hydraulic pipe 27, which can be a ceramic fiber pipe or a stainless steel alloy pipe.

[0071] The hydraulic pipe 27 and the inlet valve 21 are detachably connected. When conducting high-temperature and high-cycle vibration fatigue tests, the hydraulic pipe 27 can be separated from the inlet valve 21 to avoid interference from the pipeline to the test.

[0072] The other end of the hydraulic pipe 27 is connected to an electric hydraulic pump. The electric hydraulic pump draws hydraulic fluid from the oil tank, compresses it through its internal high-pressure chamber, and then delivers it to the interior of the central cylinder 20 through the hydraulic pipe 27. The high-pressure hydraulic fluid enters the interior of the single cylinder 22 from the branch port 23 and pushes the piston 25 inside the single cylinder 22. The piston 25 drives the push rod 24 to push outward from the interior of the single cylinder 22, clamping and fixing the irregularly shaped blade clamping end in the blade clamping end mounting groove 3. Multiple push rods 24 clamp the irregularly shaped blade clamping end at different positions. The extension lengths of the multiple push rods 24 are different, so as to achieve a fit with the irregular shape of the blade clamping end and ensure the stability of the clamping. Because multiple single cylinders 22 and the central cylinder 20 are connected to the central cylinder 20, the hydraulic fluid is compressed and then pumped into the central cylinder 20. Since the cylinders 20 are connected, the pressure inside each single cylinder 22 is the same, and the thrust of the push rod 24 is also the same. The pressure of the central cylinder 20 is controlled simultaneously by multiple push rods 24. During clamping operations, it is only necessary to control the pressure inside the central cylinder 20. This is achieved by controlling the amount and pressure of hydraulic fluid delivered to the central cylinder 20 by the electric hydraulic pump. A pressure transmitter is installed on the hydraulic pipe 27 to monitor the pressure of the delivered hydraulic fluid. The pressure transmitter is connected to the control module. When the pressure reaches the set value, the inlet valve 21 is closed, and the electric hydraulic pump is shut down through the control module, so that the pressure inside the central cylinder 20 and the single cylinders 22 remains stable, allowing the push rod 24 to stably clamp the blade clamping end.

[0073] In test environments below 200 degrees Celsius, silicone oil was used as the hydraulic fluid medium.

[0074] In the test environment ranging from 200 degrees to 800 degrees, the hydraulic fluid uses liquid silicone 800 degrees as the medium. Liquid silicone 800 degrees is a special liquid material that can flow in an environment with an altitude of 800 degrees.

[0075] Example 4:

[0076] Please see Figure 11-12In conjunction with Embodiment 3, the difference between Embodiment 3 and Embodiment 3 is that hydraulic fluid is stored inside the central cylinder 20 and several individual cylinders 22. A pressure regulating disc 28 slides inside the central cylinder 20 and is slidably sealed to the inner wall of the central cylinder 20. A central threaded post 29 is fixedly connected to the middle of the side of the pressure regulating disc 28 away from the individual cylinders 22. The central threaded post 29 penetrates the central cylinder 20 and extends to the outside of the fastener mounting platform 4. A turntable 30 is fixedly connected to one end of the central threaded post 29 located outside the mounting platform 4. The central threaded post 29 is threadedly connected to the side wall of the central cylinder 20. The pressure regulating disc 28 divides the central cylinder 20 into an air chamber 31 and a fluid chamber 32. Hydraulic fluid fills the space between the fluid chamber 32 and the interior of the individual cylinders 22.

[0077] The turntable 30 drives the central threaded post 29 to rotate, and the central threaded post 29 engages with the central cylinder 20 through a threaded connection.

[0078] When the central threaded column 29 rotates in the forward direction, it pushes the pressure regulating plate 28 along the axial direction to compress the hydraulic fluid inside the fluid chamber 32. Due to the incompressibility of the hydraulic fluid, the hydraulic fluid generates pressure inside the single cylinder 22, thereby pushing the push rod 24 to extend outward from inside the single cylinder 22 and clamp it to the blade clamping end. This structure is the same as the principle of Embodiment 3, but the pressure source for applying pressure is different. This structure uses the central threaded column 29 to push the pressure regulating plate 28 to move, thereby pressurizing the hydraulic fluid inside the fluid chamber 32. The mechanical pressurization method is more direct and suitable for reducing the fluidity requirements of the hydraulic fluid.

[0079] The hydraulic fluid in this solution is liquid silicone at 800 degrees Celsius; the hydraulic fluid can also be a high-temperature resistant nanofluid, such as silicon oxide nanofluid or boron nitride (BN) nanofluid.

[0080] Liquid metal alloys can also be used as hydraulic fluids, such as Sn-Bi alloys, in which the content of bismuth is 60% and the content of tin is 40%. The melting point of this alloy is close to 200°C, and it remains liquid at 800°C. In use, the interior of the central cylinder 20 is first heated to 200°C, and then the above-mentioned hydraulic pushing clamping operation is performed. The Sn-Bi alloy remains liquid under the experimental environment of 800°C.

[0081] For example, Sn-Bi alloy, an alloy of tin and lead, contains 60% tin and 40% lead. This alloy has a melting point of around 183°C and remains liquid at 800°C.

[0082] The high-temperature resistant spring 9 uses the Inconel X-750 high-temperature resistant spring 9, which can withstand temperatures up to 800°C and above.

[0083] Furthermore, the push rod 24 is equipped with outwardly opening grippers at one end near the mounting groove 3. When the push rod 24 moves toward the blade clamping end, the opening grippers first contact the blade clamping end and then further open outward to form multi-point contact, further enhancing the friction and improving the clamping stability of the clamp on the blade clamping end.

[0084] Although specific embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these specific embodiments without departing from the principles and spirit, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A general-purpose fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped blades, comprising a main structure (1) connected to a resonance table and a clamping structure for fixing irregular workpieces, wherein the bottom of the main structure (1) has a through hole (2) for mounting and connecting with the resonance table, the clamping structure is mounted on the cylindrical main structure (1), and the upper part of the main structure (1) is provided with a mounting groove (3) for placing the blade clamping end; a mounting platform (4) supporting the clamping structure is fixedly connected above the mounting groove (3) of the main structure (1); characterized in that, The clamping structure includes multiple fasteners with independently adjustable clamping spacing and a drive unit that pushes the fasteners to clamp. The mounting platform (4) has a guide hole on the side near the mounting groove (3) for the fasteners to pass through. The drive unit pushes multiple fasteners with independently adjustable clamping spacing through the guide hole to clamp the irregular workpiece inside the mounting groove (3).

2. The universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped end blades according to claim 1, characterized in that: The diameter and height of the main structure (1) are obtained by finite element simulation calculation based on the vibration frequency and vibration magnitude of the blade test piece. When the resonance frequency of the main structure (1) matches the resonance frequency of the blade, the main structure (1) amplifies the vibration from the blade through the clamping structure. The main structure (1) uses different types of metal materials depending on the test temperature. When the test temperature is below 800℃, the material of the main structure (1) is high-temperature alloy GH5188. When the test temperature is above 800℃, the material of the main structure (1) is single crystal high-temperature alloy.

3. The universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped end blades according to claim 2, characterized in that: The fastener is a high-temperature resistant, fully threaded screw (5), the driving part is a driving nut (6) integrally formed with the screw (5), the guide hole is a threaded hole (7) that mates with the screw (5), and there are multiple threaded holes (7) arranged in a matrix; the screw (5) and the driving nut (6) are made of different materials depending on the test temperature. For temperatures below 400℃, 310S high-temperature alloy is used; for temperatures below 800℃, high-temperature alloy GH5188 is used; and for temperatures above 800℃, DD426 nickel-based high-temperature alloy is used.

4. The universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped end blades according to claim 1, characterized in that: The fastener is a sliding toothed rod (8), the driving part is a high-temperature resistant spring (9) fixedly connected to the sliding toothed rod (8), the guide hole is a sliding hole (26), there are multiple sliding holes (26) arranged in a matrix, the installation platform (4) has a control room inside, and a locking component for locking the position of the sliding toothed rod (8) is installed inside the control room; The sliding toothed rod (8) is divided into a smooth section and a flat toothed section. The smooth section of the sliding toothed rod (8) is sleeved inside the sliding hole (26). The flat toothed section of the sliding toothed rod (8) is located inside the control room. The high temperature resistant spring (9) is located inside the control room. Each sliding toothed rod (8) is independently equipped with a high temperature resistant spring (9). The high temperature resistant spring (9) pushes the sliding toothed rod (8) towards the blade clamping end mounting groove (3). The locking assembly includes a positioning clamp and a first threaded post (10). The positioning clamp includes a first clamp (11) and a second clamp (12). Both the first clamp (11) and the second clamp (12) are provided with flat tooth grooves (13) that cooperate with the flat tooth section surface of the sliding toothed rod (8). The first clamp (11) and the second clamp (12) are symmetrically arranged inside the control room. The surface of the first threaded post (10) includes two symmetrically arranged threads. The first clamp (11) and the second clamp (12) are respectively installed outside the two symmetrically arranged threads.

5. The universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped end blades according to claim 4, characterized in that: The locking components are provided in multiple sets, and the multiple sets of locking components are arranged in parallel. The first threaded post (10) of two adjacent locking components are fixedly connected. The side of the mounting platform (4) away from the mounting groove (3) is rotatably connected to the drive post (14). The drive post (14) is fixedly connected to the end of the first threaded post (10) near it. The end of the drive post (14) away from the first threaded post (10) is integrally formed with a prism-shaped nut.

6. The universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped end blades according to claim 5, characterized in that: An elastic positioning sleeve is fitted around the drive column (14). The elastic positioning sleeve includes an inner cylinder (16) and an outer cylinder (17). The outer part of the inner cylinder (16) is prismatic, and the outer part of the outer cylinder (17) is cylindrical. The outer cylinder (17) is slidably fitted around the outer part of the inner cylinder (16). A high-temperature spring (9) is between the inner cylinder (16) and the outer cylinder (17). The high-temperature spring (9) pushes the inner cylinder (16) and the outer cylinder (17) to extend outward. The high-temperature spring (9) contracts when subjected to radial pressure. The nut of the drive column (14) is fixedly connected to the inner cylinder (16). An annular toothed ring (18) is provided on the side of the outer cylinder (17) near the mounting platform (4). An annular toothed groove (19) matching the annular toothed ring (18) is provided on the mounting platform (4) near the outer cylinder (17).

7. The universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped end blades according to claim 1, characterized in that: The drive unit is a hydraulic drive component, which includes a central cylinder (20). The central cylinder (20) is installed inside the mounting platform (4) of the fastener. An inlet valve (21) is installed on the side of the central cylinder (20) away from the mounting groove (3). Multiple single cylinders (22) are fixedly connected to the side of the central cylinder (20) close to the mounting groove (3). A diversion port (23) is provided between the single cylinder (22) and the central cylinder (20). The fastener is a push rod (24), which is slidably sleeved inside the single cylinder (22). A piston (25) is provided at one end of the push rod (24) near the central cylinder (20). The piston (25) is slidably sealed to the inner wall of the single cylinder (22). The guide hole is a sliding hole (26), and the push rod (24) passes through the inside of the sliding hole (26). A high-temperature resistant hydraulic pipe (27) is connected to the inlet valve (21) of the central cylinder (20). The hydraulic pipe (27) and the inlet valve (21) are detachably connected. The other end of the hydraulic pipe (27) is connected to an electric hydraulic pump for pressurizing the hydraulic fluid. A pressure transmitter for monitoring the pressure of the conveyed hydraulic fluid is installed on the hydraulic pipe (27).

8. The universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped end blades according to claim 7, characterized in that: In test environments below 200 degrees Celsius, silicone oil is used as the medium for hydraulic fluid; in test environments between 200 and 800 degrees Celsius, liquid silicone at 800 degrees Celsius is used as the medium for hydraulic fluid.

9. The universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped end blades according to claim 7, characterized in that: The hydraulic fluid is stored inside a central cylinder (20) and several individual cylinders (22). A pressure regulating disc (28) slides inside the central cylinder (20). The pressure regulating disc (28) is slidably sealed to the inner wall of the central cylinder (20). A central threaded column (29) is fixedly connected to the middle of the side of the pressure regulating disc (28) away from the individual cylinders (22). The central threaded column (29) passes through the central cylinder (20) and extends to the outside of the fastener mounting platform (4). A turntable (30) is fixedly connected to one end of the central threaded column (29) located outside the mounting platform (4). The central threaded column (29) is threadedly connected to the side wall of the central cylinder (20). The pressure regulating disc (28) divides the central cylinder (20) into an air chamber (31) and a fluid chamber (32). The hydraulic fluid fills the space between the fluid chamber (32) and the interior of the individual cylinders (22).

10. The universal fixture for high-temperature, high-cycle vibration fatigue testing of irregularly clamped end blades according to claim 9, characterized in that: The hydraulic fluid is a high-temperature resistant nanofluid or liquid metal alloy; the liquid metal alloy is a Sn-Bi alloy, in which the bismuth content is 60% and the tin content is 40%. The melting point of the alloy is close to 200°C, and it remains liquid at 800°C. In use, the interior of the central cylinder (20) is first heated to 200°C, and then the above-mentioned hydraulic push clamping operation is performed. The Sn-Bi alloy remains liquid under the experimental environment of 800°C.

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