High-temperature tensile creep testing device for ceramic-based composite material

Abstract

The invention discloses a high-temperature tensile creep testing device for a ceramic matrix composite material, and relates to the technical field of composite material performance tests.The technical scheme includes that the high-temperature tensile creep testing device comprises a testboard, a tensile shell is fixedly connected to the upper portion of the testboard, a servo motor is arranged in the tensile shell, and a worm is arranged at the output end of the servo motor; the worm is rotationally connected with the stretching shell, the worm is in meshed connection with a worm gear, the worm gear is rotationally connected with the stretching shell, the worm gear is fixedly connected with a transmission gear, the transmission gear is in meshed connection with a stretching rack, and the upper portion of the stretching rack is rotationally connected with two clamps. Due to the fact that a wedge-shaped structure is formed between the clamp and the clamping groove, the clamp can clamp inwards while moving downwards, the clamping force borne by the two sides of the ceramic matrix composite sample is increased along with increase of the tensile strength, and the slippage phenomenon caused by the fact that the tensile strength of the two sides of the ceramic matrix composite sample is improved is effectively avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material performance testing, in particular to a high-temperature tensile creep testing device for ceramic-based composite materials. Background Art

[0002] Ceramic-based composites have important application prospects in the fields of hot-end components of aero-engines and thermal protection of spacecraft due to their combination of high-temperature resistance and fiber toughening effects. Their high-temperature creep performance is a core indicator for evaluating the long-term service reliability of materials. Traditional creep test devices are mostly designed for metal materials, and have problems such as insufficient loading accuracy, poor temperature gradient control, and data acquisition delays. They are difficult to adapt to the brittle and stress-sensitive characteristics of ceramic-based composites. The test device designed based on the concept of an automatic capture cage achieves dynamic load compensation through a servo closed-loop system. Combined with a non-contact laser displacement sensor and a thermocouple array, it can simultaneously capture micron-level creep deformation and real-time temperature field distribution. At the same time, a vacuum-inert gas dual-mode environmental chamber is used to suppress high-temperature oxidation interference, providing technical support for studying the creep mechanism of materials in ultra-high temperature environments above 1500°C.

[0003] In actual use of existing devices, when ceramic matrix composite materials are stretched, the specimen may slip as the load increases. In addition, as the material thermally expands at high temperatures, stress concentrates at the ends of the specimen. Therefore, a high-temperature tensile creep test device for ceramic matrix composites is proposed. Summary of the Invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art that when ceramic-based composite materials are stretched, the specimen may slip as the load increases, and the stress concentration at the end of the specimen occurs as the material thermally expands at high temperatures. A high-temperature tensile creep testing device for ceramic-based composite materials is proposed.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A high-temperature tensile creep test device for ceramic-based composite materials comprises a test bench, wherein the upper portion of the test bench is fixedly connected to a tensile shell, a servo motor is provided inside the tensile shell, a worm is provided at the output end of the servo motor, the worm is rotatably connected to the tensile shell, the worm is meshingly connected to a worm wheel, the worm wheel is rotatably connected to the tensile shell, the worm wheel is fixedly connected to a transmission gear, the transmission gear is meshingly connected to a tensile rack, the upper portion of the tensile rack is rotatably connected to two clamps, the two clamps are slidably connected to a clamping groove, and the two clamps clamp one end of a ceramic-based composite material sample.

[0007] During the test, loads need to be applied to both ends of the ceramic-based composite material sample under a high-temperature environment. First, the two ends of the ceramic-based composite material sample are placed in the middle of the fixture, and then the servo motor is started. The servo motor drives the worm to rotate, and the rotation of the worm drives the stretching rack to move downward. The movement of the stretching rack drives the rotating connected fixture to clamp inward and move downward at the same time, clamping and stretching at the same time. Moreover, through the wedge-shaped structure of the fixture and the clamping groove, the clamping force of the fixture changes with the stretching, realizing dynamic clamping and avoiding the slippage of the ceramic-based composite material sample due to increased tensile strength.

[0008] The above technical solution further includes:

[0009] The interior of the stretching shell is fixedly connected to a limiting groove, and the interior of the limiting groove is slidably connected to a stretching rack.

[0010] A connecting plate is fixedly connected to the lower portion of the clamping groove, and an end of the connecting plate away from the clamping groove is fixedly connected to a stretching shell.

[0011] A flexible gasket is fixedly connected to a side of the clamp away from the clamping groove, and the flexible gasket is made of a soft and high-temperature resistant material.

[0012] A heating furnace is provided on the upper portion of the test bench, and a handle is fixedly connected to one side of the heating furnace.

[0013] A device base is provided at the lower part of the test bench, and the test bench and the device base are slidably connected.

[0014] A damping shell is fixedly connected inside the device base, a guide rod is slidably connected to the upper part of the damping shell, a shock absorbing plate is fixedly connected to the upper part of the guide rod, and the shock absorbing plate is fixedly connected to the test bench.

[0015] An oil chamber is provided inside the damping shell, a piston is slidably connected to the upper part of the oil chamber, the piston is fixedly connected to the guide rod, a damping hole is provided on the upper part of the piston, and the number of the damping holes is several. Damping medium is provided inside the oil chamber.

[0016] Sealing plates are provided at both ends of the oil chamber, a spring is fixedly connected to an upper portion of the sealing plate, and a damping shell is fixedly connected to an upper portion of the spring.

[0017] The present invention has the following beneficial effects:

[0018] 1. In the present invention, during the test, the two ends of the ceramic-based composite material sample are respectively placed in the middle of the clamp, and then the servo motor is started. The servo motor drives the stretching rack to move downward, thereby driving the clamp to close inward to clamp the ceramic-based composite material sample. Then the heating furnace is closed to heat the ceramic-based composite material sample. When stretching is required, the servo motor is started again to drive the stretching rack to move downward. Since there is a wedge-shaped structure between the clamp and the clamping groove, the clamp will clamp inward while moving downward, so that the clamping force on both sides of the ceramic-based composite material sample increases with the increase of tensile strength, effectively avoiding the slippage phenomenon caused by the increase of tensile strength on both sides of the ceramic-based composite material sample. The flexible gasket arranged on the surface of the clamp can also reduce the risk of stress concentration at the end of the ceramic-based composite material sample, and adapt to the thermal expansion changes of the material under high temperature.

[0019] 2. In the present invention, as the ceramic-based composite material sample is continuously stretched, the test bench will vibrate due to the operation of the stretching device. When the vibration occurs, the test bench will drive the guide rod to move, and the movement of the guide rod can drive the piston to move. When the piston moves, the damping medium inside the spring can effectively absorb the kinetic energy through the damping hole, and the spring arranged at the bottom of the piston will also be deformed under the movement of the guide rod, thereby further improving the buffering effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic structural diagram of a high-temperature tensile creep testing device for ceramic matrix composites proposed in the present invention;

[0021] Figure 2 It is a top view of the overall structure of the device in the present invention;

[0022] Figure 3 Schematic diagram of the internal structure of the clamping groove in the present invention;

[0023] Figure 4 Schematic diagram of the internal structure of the stretch shell in the present invention;

[0024] Figure 5 Schematic diagram of the internal structure of the device base in the present invention;

[0025] Figure 6 Schematic diagram of the internal structure of the damping shell in the present invention.

[0026] In the figure: 1. Test bench; 2. Device base; 3. Tensile shell; 4. Heating furnace; 5. Handle; 6. Clamping groove; 7. Ceramic matrix composite material specimen; 8. Flexible gasket; 9. Connecting plate; 10. Clamp; 11. Tensile rack; 12. Servo motor; 13. Worm; 14. Worm gear; 15. Transmission gear; 16. Limiting groove; 17. Shock-absorbing plate; 18. Guide rod; 19. Damping shell; 20. Piston; 21. Damping hole; 22. Oil chamber; 23. Spring; 24. Sealing plate. DETAILED DESCRIPTION

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] Example 1

[0029] like Figures 1-6 As shown, a high-temperature tensile creep test device for ceramic-based composite materials includes a test bench 1, a tensile shell 3 is fixedly connected to the upper part of the test bench 1, a servo motor 12 is arranged inside the tensile shell 3, a worm 13 is arranged at the output end of the servo motor 12, the worm 13 is rotatably connected to the tensile shell 3, the worm 13 is meshedly connected to a worm gear 14, the worm gear 14 is rotatably connected to the tensile shell 3, the worm gear 14 is fixedly connected to a transmission gear 15, the transmission gear 15 is meshedly connected to a tensile rack 11, the upper part of the tensile rack 11 is rotatably connected to two clamps 10, the two clamps 10 are slidably connected to the clamping groove 6, and the two clamps 10 clamp one end of the ceramic-based composite material sample 7.

[0030] During the test, it is necessary to apply loads to both ends of the ceramic-based composite material sample 7 under a high-temperature environment. First, the two ends of the ceramic-based composite material sample 7 are placed in the middle of the clamp 10 respectively, and then the servo motor 12 is started. The servo motor 12 drives the worm 13 to rotate, and the rotation of the worm 13 drives the stretching rack 11 to move downward. The movement of the stretching rack 11 drives the rotating connected clamp 10 to clamp inward and move downward at the same time, clamping and stretching at the same time. Moreover, through the wedge-shaped structure of the clamp 10 and the clamping groove 6, the clamping force of the clamp 10 changes with the stretching, realizing dynamic clamping and avoiding the slippage of the ceramic-based composite material sample 7 due to the increase in tensile strength.

[0031] The interior of the stretching shell 3 is fixedly connected to a limiting groove 16, and the interior of the limiting groove 16 is slidably connected to a stretching rack 11. The lower part of the clamping groove 6 is fixedly connected to a connecting plate 9, and the connecting plate 9 is fixedly connected to the stretching shell 3 at one end away from the clamping groove 6. The side of the clamp 10 away from the clamping groove 6 is fixedly connected to a flexible gasket 8. The flexible gasket 8 is made of soft material and is resistant to high temperatures. A heating furnace 4 is provided on the upper part of the test bench 1, and a handle 5 is fixedly connected to one side of the heating furnace 4.

[0032] In this embodiment, during the test, the two ends of the ceramic-based composite material sample 7 are placed in the middle of the fixture 10 respectively, and then the servo motor 12 is started. The servo motor 12 can drive the worm 13 to rotate, and the rotation of the worm 13 drives the meshing worm wheel 14 to rotate, and the rotation of the worm wheel 14 can drive the fixedly connected transmission gear 15 to rotate. The rotation of the transmission gear 15 can drive the meshing connected stretching rack 11 to move downward, and the sliding connection limit groove 16 during the movement of the stretching rack 11 can ensure the stability of the stretching rack 11 when it moves, and the movement of the stretching rack 11 can drive the rotatably connected fixture 10 to close inward, thereby testing the ceramic-based composite material sample 7. The ceramic matrix composite material sample 7 is clamped, and then the heating furnace 4 is closed by the handle 5 to heat the ceramic matrix composite material sample 7. When stretching is required, the servo motor 12 is started again to drive the stretching rack 11 to move downward. Since there is a wedge-shaped structure between the clamp 10 and the clamping groove 6, the clamp 10 will clamp inward while moving downward, so that the clamping force on both sides of the ceramic matrix composite material sample 7 increases with the increase of tensile strength, effectively avoiding the slippage phenomenon caused by the increase of tensile strength on both sides of the ceramic matrix composite material sample 7. The flexible gasket 8 arranged on the surface of the clamp 10 can also reduce the risk of stress concentration at the end of the ceramic matrix composite material sample 7, and adapt to the thermal expansion changes of the material under high temperature.

[0033] Example 2

[0034] like Figures 1-6 As shown, a device base 2 is provided at the lower part of the test bench 1, and the test bench 1 and the device base 2 are slidably connected. A damping shell 19 is fixedly connected inside the device base 2. A guide rod 18 is slidably connected to the upper part of the damping shell 19, and a shock-absorbing plate 17 is fixedly connected to the upper part of the guide rod 18. The shock-absorbing plate 17 is fixedly connected to the test bench 1. An oil chamber 22 is provided inside the damping shell 19, and a piston 20 is slidably connected to the upper part of the oil chamber 22. The piston 20 is fixedly connected to the guide rod 18, and a damping hole 21 is provided on the upper part of the piston 20. There are several damping holes 21. Damping medium is provided inside the oil chamber 22, and sealing plates 24 are provided at both ends of the oil chamber 22. A spring 23 is fixedly connected to the upper part of the sealing plate 24, and the upper part of the spring 23 is fixedly connected to the damping shell 19.

[0035] In this embodiment, as the ceramic-based composite material sample 7 is continuously stretched, the test bench 1 will vibrate due to the operation of the stretching device. When the vibration occurs, the test bench 1 will drive the guide rod 18 to move, and the movement of the guide rod 18 can drive the piston 20 set at the bottom to move inside the oil chamber 22. Since a damping medium is provided inside the oil chamber 22, the damping medium will pass through the damping hole 21 provided on the upper part of the piston 20 during the movement of the piston 20, thereby generating throttling resistance to absorb the kinetic energy generated by the vibration, thereby achieving the purpose of shock absorption, and the dense spring 23 provided at the lower part of the piston 20 will also be deformed under the movement of the guide rod 18, thereby further improving the buffering effect.

[0036] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high-temperature tensile creep test device for ceramic matrix composite materials, comprising a test bench (1), characterized in that: The upper portion of the test bench (1) is fixedly connected to a stretching housing (3), a servo motor (12) is provided inside the stretching housing (3), a worm (13) is provided at the output end of the servo motor (12), the worm (13) is rotationally connected to the stretching housing (3), the worm (13) is meshedly connected to a worm wheel (14), the worm wheel (14) is rotationally connected to the stretching housing (3), the worm wheel (14) is fixedly connected to a transmission gear (15), the transmission gear (15) is meshedly connected to a stretching rack (11), the upper portion of the stretching rack (11) is rotationally connected to two clamps (10), the two clamps (10) are slidably connected to the clamping groove (6), and the two clamps (10) clamp one end of the ceramic-based composite material sample (7); During the test, loads need to be applied to both ends of the ceramic-based composite material sample (7) in a high-temperature environment. First, the two ends of the ceramic-based composite material sample (7) are respectively placed in the middle of the clamp (10), and then the servo motor (12) is started. The servo motor (12) drives the worm (13) to rotate, and the rotation of the worm (13) drives the stretching rack (11) to move downward. The movement of the stretching rack (11) drives the rotationally connected clamp (10) to clamp inward and move downward at the same time, and clamping and stretching are performed simultaneously. Moreover, through the wedge-shaped structure of the clamp (10) and the clamping groove (6), the clamping force of the clamp (10) changes with the stretching change, realizing dynamic clamping and avoiding the slippage of the ceramic-based composite material sample (7) due to the increase in tensile strength.

2. The high temperature tensile creep testing device for ceramic matrix composite materials according to claim 1, characterized in that: A limiting groove (16) is fixedly connected inside the stretching shell (3), and a stretching rack (11) is slidably connected inside the limiting groove (16).

3. The high temperature tensile creep testing device for ceramic matrix composite materials according to claim 1, characterized in that: A connecting plate (9) is fixedly connected to the lower portion of the clamping groove (6), and an end of the connecting plate (9) away from the clamping groove (6) is fixedly connected to the stretching shell (3).

4. The high temperature tensile creep testing device for ceramic matrix composite materials according to claim 1, characterized in that: A flexible gasket (8) is fixedly connected to the side of the clamp (10) away from the clamping groove (6).

5. The high temperature tensile creep testing device for ceramic matrix composite materials according to claim 1, characterized in that: A heating furnace (4) is provided on the upper portion of the test bench (1), and a handle (5) is fixedly connected to one side of the heating furnace (4).

6. The high temperature tensile creep testing device for ceramic matrix composite materials according to claim 1, characterized in that: A device base (2) is provided at the lower part of the test bench (1), and the test bench (1) and the device base (2) are slidably connected.

7. The high temperature tensile creep testing device for ceramic matrix composite materials according to claim 6, characterized in that: A damping shell (19) is fixedly connected to the inside of the device base (2); a guide rod (18) is slidably connected to the upper portion of the damping shell (19); a damping plate (17) is fixedly connected to the upper portion of the guide rod (18); and the damping plate (17) is fixedly connected to the test bench (1).

8. The high temperature tensile creep testing device for ceramic matrix composite materials according to claim 7, characterized in that: An oil chamber (22) is provided inside the damping housing (19), a piston (20) is slidably connected to the upper portion of the oil chamber (22), the piston (20) is fixedly connected to the guide rod (18), and a damping hole (21) is provided on the upper portion of the piston (20).

9. The high temperature tensile creep testing device for ceramic matrix composite materials according to claim 8, characterized in that: Sealing plates (24) are provided at both ends of the oil chamber (22), a spring (23) is fixedly connected to the upper portion of the sealing plate (24), and a damping housing (19) is fixedly connected to the upper portion of the spring (23).

Images