High-temperature strain fatigue extensometer strain fine adjustment device and fine adjustment method

Abstract

This invention discloses a strain fine-tuning device and method for a high-temperature strain fatigue extensometer. The extensometer includes a first high-temperature ceramic rod and a second high-temperature ceramic rod distributed vertically. The strain fine-tuning device includes: a clamping mechanism, comprising a first bracket for cooperating with the first high-temperature ceramic rod and a second bracket for cooperating with the second high-temperature ceramic rod, the first bracket and the second bracket being rotatably connected; and an adjustment mechanism, used to mount the clamping mechanism and to drive the first bracket and the second bracket to swing relative to each other at a preset angle based on their hinge point, thereby acting on the first high-temperature ceramic rod and the second high-temperature ceramic rod respectively. By adjusting the relative angle of the first and second brackets, which are rotatably connected, with extremely small adjustments by the adjustment mechanism, the strain of the extensometer can be finely adjusted in a high-temperature environment, solving the stress response distortion and average stress deviation caused by thermal expansion, and avoiding life deviation.

Description

Technical Field

[0001] This invention relates to the field of fatigue performance testing technology for metallic materials, and in particular, to a strain fine-tuning device for a high-temperature strain fatigue extensometer. Furthermore, this invention also relates to a method for fine-tuning the strain of a high-temperature strain fatigue extensometer, including the aforementioned strain fine-tuning device. Background Technology

[0002] With the development of aerospace and energy power (such as gas turbines, aero engines, and nuclear reactors), many key components (such as turbine blades, engine hot-end components, and heat exchanger pipes) need to operate for extended periods under the combined effects of high temperatures and cyclic loads (i.e., fatigue loads). This places high demands on the design of mechanical components that withstand fatigue loads and cyclic deformation, thus requiring precise data from laboratory testing of metallic materials. To design and evaluate the lifespan of these components, engineers must obtain strain fatigue data of the materials under corresponding operating conditions. Traditional low-cycle fatigue testing is conducted at room temperature, where temperature variables are negligible. However, when the test temperature rises to more than 30% of the material's melting point (in absolute thermometers) (e.g., above 300°C for steel and above 600°C for nickel-based superalloys), temperature becomes a non-negligible and crucial variable. High-temperature fatigue testing directly using room-temperature methods has revealed that test results are not repeatable, extremely dispersed, and differ significantly from the actual service behavior of the components. The root cause is the influence of thermal expansion effects. In high-temperature strain-controlled fatigue tests, the extensometer measures the deformation of the gauge length of the specimen. However, it measures the total deformation and cannot distinguish between mechanical strain (caused by external loads and is the root cause of fatigue damage) and thermal strain (caused by temperature changes), which leads to stress response distortion, deviation of mean stress, and incorrect fatigue life prediction.

[0003] In existing technologies, before the high-temperature strain fatigue test begins, the extensometer zero point shifts due to the thermal expansion of the material, causing the original gauge length of the extensometer to change at high temperatures. Therefore, the extensometer zero point needs to be readjusted at high temperatures. For example, the high-temperature extensometers of INSTRON and MTS require electronic zeroing at the start of high-temperature strain fatigue to ensure that the extensometer returns to zero. This results in the zero point of the high-temperature extensometer shifting rather than the actual gauge length deviating from the actual strain value. Existing technologies mainly adjust the gauge length and electronic zeroing through manual intervention such as slight tapping.

[0004] In existing technologies such as MTS, INSTRON, and Epsilion, the gauge length is guaranteed by a positioning pin in room temperature extensometers. Since there is no influence of material thermal expansion in room temperature tests, the positioning pin is removed immediately at the start of the test. High temperature extensometers do not have this device, and the original gauge length cannot be finely adjusted.

[0005] Currently, there are several methods for zeroing the extensometer when the testing machine force is zero during high-temperature strain fatigue testing: manual adjustment of the gauge length through slight tapping or other interventions, and electronic zeroing. However, these methods have the following drawbacks: 1. Strain fluctuations caused by tapping vibrations; 2. Inaccurate and arbitrary adjustments; 3. Electronic zeroing causes a shift in the zero strain point rather than the true gauge length.

[0006] Existing technologies rely on software algorithms for compensation. The core drawback is that software compensation depends entirely on the relationship curve obtained from zero-load temperature cycling tests. This assumes that the specimen used to measure thermal expansion is in the same state as the subsequent fatigue specimen, and that the test conditions are perfectly reproducible. However, in reality, material differences, temperature errors, and systematic repeatability errors affect the coefficient of thermal expansion, leading to inaccurate compensation curves. This error is continuously introduced throughout the fatigue test, causing systematic deviations in mechanical strain control. Software-based thermal expansion compensation is a practical but not foolproof technique; its effectiveness rests on a series of idealized assumptions, such as stable specimen conditions, uniform temperature fields, and accurate measurements. Summary of the Invention

[0007] This invention provides a high-temperature strain fatigue extensometer strain fine-tuning device and method to solve the technical problem of…

[0008] According to one aspect of the present invention, a strain fine-tuning device for a high-temperature strain fatigue extensometer is provided. The extensometer includes a first high-temperature ceramic rod and a second high-temperature ceramic rod distributed vertically. The strain fine-tuning device includes: The clamping mechanism includes a first bracket for cooperating with the first high-temperature ceramic rod and a second bracket for cooperating with the second high-temperature ceramic rod, wherein the first bracket and the second bracket are rotatably connected. An adjustment mechanism is used to install the clamping mechanism and to drive the first bracket and the second bracket to swing relative to each other at a preset angle based on the hinge point between them, thereby acting on the first high-temperature ceramic rod and the second high-temperature ceramic rod respectively.

[0009] As a further improvement to the above technical solution, the adjustment mechanism includes an adjustment screw, which passes through the first bracket and is threadedly connected to the second bracket, or the adjustment screw passes through the second bracket and is threadedly connected to the first bracket; the adjustment screw is fitted with an elastic element located between the first bracket and the second bracket, and the two ends of the elastic element are used to act on the first bracket and the second bracket respectively.

[0010] As a further improvement to the above technical solution, the second bracket includes a first fixed support plate and a second fixed support plate, as well as a locking member for connecting the first fixed support plate and the second fixed support plate. The first fixed support plate is used to clamp the second high-temperature ceramic rod from above, and the second fixed support plate is used to clamp the second high-temperature ceramic rod from below. The locking member is used to lock and fix the first fixed support plate and the second fixed support plate.

[0011] As a further improvement to the above technical solution, the first bracket includes a mating part and a connecting part. The top and bottom of the mating part are respectively provided with a first mating structure for mating with the first high-temperature ceramic rod. The connecting part is used for rotatably connecting with the second bracket. The end of the connecting part protrudes towards the second bracket to form a protrusion for installing the adjusting screw, so that the axis of the adjusting screw is perpendicular to the axis of the first high-temperature ceramic rod.

[0012] As a further improvement to the above technical solution, the first mating structure includes a first arc-shaped groove formed in the first bracket, the radial dimension of the first arc-shaped groove being larger than the radial dimension of the first high-temperature ceramic rod; the first arc-shaped groove is used to abut against the side wall of the first high-temperature ceramic rod.

[0013] As a further improvement to the above technical solution, the first fixed support plate includes a horizontal portion that matches the second fixed support plate and an inclined portion for rotatably connecting with the first bracket.

[0014] As a further improvement to the above technical solution, the adjustment mechanism includes an adjustment screw, which is threadedly connected to the first bracket and axially limited to the second bracket; or, the adjustment screw is threadedly connected to the second bracket and axially limited to the first bracket.

[0015] According to another aspect of the present invention, a method for fine-tuning the strain of a high-temperature strain fatigue extensometer is also provided, comprising the above-mentioned high-temperature strain fatigue extensometer strain fine-tuning device, wherein the fine-tuning method comprises: S1. Security check; S2. Install the extensometer; S3. Confirm the problem direction and select the adjustment direction; S4. Install the clamping mechanism and adjustment mechanism; S5. Based on the real-time strain reading, the fulcrum position of the first high-temperature ceramic rod and / or the second high-temperature ceramic rod is finely adjusted by the adjustment mechanism until the strain value reading meets the requirements; S6. After the strain stabilizes, remove the adjustment device; S7. Conduct the experiment.

[0016] As a further improvement to the above technical solution, step S3 includes: adjusting the direction of the adjustment mechanism according to the trend of strain value change after heat preservation.

[0017] Step S5 includes: S51. Temperature begins to rise; S52. Maintain heat after heating; S53. When the load on the testing machine is zero, the fulcrum position of the first high-temperature ceramic rod and / or the second high-temperature ceramic rod is finely adjusted by the adjustment mechanism based on the real-time strain reading until the strain value reading meets the requirements.

[0018] The present invention has the following beneficial effects: This strain fine-tuning device employs a clamping mechanism and an adjustment mechanism. The first and second supports of the clamping mechanism abut against the first and second high-temperature ceramic rods of the extensometer, respectively. The adjustment mechanism makes minute adjustments to the relative angle between the first and second supports, thereby acting on the first and / or second high-temperature ceramic rods. This allows for strain fine-tuning of the extensometer under high-temperature conditions, ensuring gauge length accuracy, resolving stress response distortion and average stress deviation caused by thermal expansion, avoiding lifespan deviations, and eliminating problems caused by inaccurate "zero-load temperature cycling" tests and thermocouple adhesion. This device addresses systematic errors introduced by improper placement or other pre-operational mistakes. Furthermore, it ensures that the extensometer gauge length after adjustment is the actual gauge length rather than the electronically zeroed value to eliminate errors. Without disassembling the extensometer, it precisely restores the initial strain value in a high-temperature environment. The application of this device is particularly effective in testing anisotropic materials, providing more robust support for obtaining accurate high-temperature fatigue data. Adjusting at high temperatures using this strain fine-tuning device effectively avoids burns caused by manual adjustment, and the adjustment process is smoother, preventing vibrations caused by tapping or other impacts on the extensometer, thus avoiding strain fluctuations and ensuring precise adjustment.

[0019] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a usage status reference for a preferred embodiment of the present invention. Figure 1 ; Figure 2 This is a usage status reference for a preferred embodiment of the present invention. Figure 2 ; Figure 3This is a schematic diagram of the structure of the first support in a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the second support in a preferred embodiment of the present invention; Figure 5 This is a usage status reference of another embodiment of the present invention. Figure 1 ; Figure 6 This is a usage status reference of another embodiment of the present invention. Figure 2 .

[0021] Legend: 100. Clamping mechanism; 110. First bracket; 111. Mating part; 112. Connecting part; 113. First mating structure; 120. Second bracket; 121. First fixed support plate; 122. Second fixed support plate; 123. Locking element; 124. Second mating structure; 125. Protrusion; 200. Adjusting mechanism; 210. Adjusting screw; 220. Elastic element; 300. Extensometer; 310. First high-temperature ceramic rod; 320. Second high-temperature ceramic rod. Detailed Implementation

[0022] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0023] Figure 1 This is a usage status reference for a preferred embodiment of the present invention. Figure 1 ; Figure 2 This is a usage status reference for a preferred embodiment of the present invention. Figure 2 ; Figure 3 This is a schematic diagram of the structure of the first support in a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the second support in a preferred embodiment of the present invention; Figure 5 This is a usage status reference of another embodiment of the present invention. Figure 1 ; Figure 6 This is a usage status reference of another embodiment of the present invention. Figure 2 .

[0024] like Figures 1 to 4 As shown, the strain fine-tuning device of the high-temperature strain fatigue extensometer 300 in this embodiment includes a first high-temperature ceramic rod 310 and a second high-temperature ceramic rod 320 distributed vertically. The strain fine-tuning device includes: The clamping mechanism 100 includes a first bracket 110 for cooperating with a first high-temperature ceramic rod 310 and a second bracket 120 for cooperating with a second high-temperature ceramic rod 320, wherein the first bracket 110 and the second bracket 120 are rotatably connected. The adjustment mechanism 200 is used to install the clamping mechanism 100 and to drive the first bracket 110 and the second bracket 120 to swing relative to each other at a preset angle based on the hinge point between them, thereby acting on the first high-temperature ceramic rod 310 and the second high-temperature ceramic rod 320 respectively to generate strain fine adjustment.

[0025] Understandably, during high-temperature strain fatigue testing, the temperature rise causes slight thermal expansion or internal stress changes in the ceramic rod system of the fixed extensometer 300. This results in strain reading distortion in the extensometer 300 under the "zero load" state after the heat preservation period and before formal loading. This strain fine-tuning device addresses this by separately setting up a clamping mechanism 100 and an adjustment mechanism 200. The first support 110 and the second support 120 of the clamping mechanism 100 respectively abut against the first high-temperature ceramic rod 310 and the second high-temperature ceramic rod 320 of the extensometer 300. The adjustment mechanism 200 makes extremely small adjustments to the relative angle between the first support 110 and the second support 120, which are rotatably connected, thereby acting on the first high-temperature ceramic rod 310 and / or the second high-temperature ceramic rod 320. This achieves strain fine-tuning of the extensometer 300 under high-temperature conditions. This device ensures the accuracy of the gauge length, resolves stress response distortion and average stress deviation caused by thermal expansion, avoids lifespan deviations, and eliminates systematic errors introduced by pre-operational mistakes such as inaccurate "zero-load temperature cycling" testing and improper thermocouple placement. Furthermore, after adjustment, the extensometer 300 gauge length is the true extensometer 300 gauge length, rather than being electronically zeroed to eliminate errors. Without disassembling the extensometer 300, it precisely restores the initial strain value in a high-temperature environment. The application of this device is particularly evident in the testing of anisotropic materials, providing more effective support for obtaining accurate high-temperature fatigue data. Adjustment using this strain fine-tuning device at high temperatures effectively avoids burns caused by manual adjustment, and the adjustment process is more stable, effectively avoiding vibrations to the extensometer 300 caused by tapping during adjustment, thus preventing strain fluctuations and ensuring precise adjustment.

[0026] In some preferred embodiments, the adjustment mechanism 200 includes an adjustment screw 210, which passes through the first bracket 110 and is threadedly connected to the second bracket 120; or, the adjustment screw 210 passes through the second bracket 120 and is threadedly connected to the first bracket 110. The adjustment screw 210 is fitted with an elastic member 220 located between the first bracket 110 and the second bracket 120, and the two ends of the elastic member 220 are used to act on the first bracket 110 and the second bracket 120 respectively. Understandably, in one specific embodiment, the adjusting screw 210 passes through the first bracket 110 and is threadedly connected to the second bracket 120. The large end of the adjusting screw 210 abuts against the first bracket 110. When the adjusting screw 210 is tightened, the large end of the adjusting screw 210 drives the first bracket 110 closer to the second bracket 120 and compresses the elastic element 220, which in turn acts on the ceramic rod of the extensometer 300 to adjust its strain. When the adjusting screw 210 is loosened, the elastic element 220 acts on the first bracket 110 and the second bracket 120, which in turn acts on the ceramic rod of the extensometer 300 to adjust its strain in another direction. The adjustment amount can be further refined by adjusting the thread. During the adjustment process, adjustments are made in small angle increments (such as 15-30 degrees), and the changes in the readings are observed. The elastic element 220 can be a spring.

[0027] In some preferred embodiments, the second bracket 120 includes a first fixed support plate 121 and a second fixed support plate 122, and a locking member 123 for connecting the first fixed support plate 121 and the second fixed support plate 122. The first fixed support plate 121 is used to clamp the second high-temperature ceramic rod 320 from above, and the second fixed support plate 122 is used to clamp the second high-temperature ceramic rod 320 from below. The locking member 123 is used to lock and fix the first fixed support plate 121 and the second fixed support plate 122. It can be understood that the second bracket 120 is constructed to include the first fixed support plate 121 and the second fixed support plate 122, which are clamped together outside the second high-temperature ceramic rod 320 and locked and fixed by the locking member 123, thereby fixing the second bracket 120 to the ceramic rod, which is convenient for installation and relatively more stable for adjustment. The locking member 123 can be a locking screw.

[0028] In some preferred embodiments, the first bracket 110 includes a mating portion 111 and a connecting portion 112. The top and bottom of the mating portion 111 are respectively provided with first mating structures 113 for mating with the first high-temperature ceramic rod 310. The connecting portion 112 is used for rotatable connection with the second bracket 120. The end of the connecting portion 112 protrudes towards the second bracket 120 to form a protrusion 125 for installing an adjusting screw 210, so that the axis of the adjusting screw 210 is perpendicular to the axis of the first high-temperature ceramic rod 310. Specifically, by... The bottom is provided with a first mating structure 113. After the adjustment direction is determined, the corresponding side surface mates with the first high temperature ceramic rod 310. The adjustment mechanism 200 controls the first bracket 110 to move relative to the second bracket 120. The adjustment is performed by acting on the first high temperature ceramic rod 310 and the second high temperature ceramic rod 320 in a fixed direction. Through the clamping installation of the second bracket 120 and the directional matching installation of the first bracket 110, rigid fixation on the extensometer 300 is avoided, and the strain is not affected during the installation process. The adjustment is more accurate and stable, and secondary impact on the gauge length is avoided. On the other hand, since the first bracket 110 and the second bracket 120 are rotatably connected and the axis of rotation is parallel to the high-temperature ceramic rod, in order to avoid interference between the two high-temperature ceramic rods which are located at different axial positions, the protrusion 125 formed by the protrusion at the end of the connecting part 112 matches the axial position of the second bracket 120. This ensures that the adjusting screw 210 and the elastic element 220 of the adjusting mechanism 200 can be installed perpendicular to the axial direction of the high-temperature ceramic rod, ensuring that the adjustment direction is perpendicular to the axes of the two high-temperature ceramic rods respectively, and that the adjustment can be controlled more precisely and more stably.

[0029] In some preferred embodiments, the first mating structure 113 includes a first arc-shaped groove formed in the first bracket 110, the radial dimension of the first arc-shaped groove being larger than the radial dimension of the first high-temperature ceramic rod 310; the first arc-shaped groove is used to abut against the side wall of the first high-temperature ceramic rod 310, and the top and bottom surfaces of the mating part 111 of the first bracket 110 are both provided with the first arc-shaped groove to accommodate and cover the first high-temperature ceramic rod 310, increase the mating area, and ensure the stability of the adjustment process.

[0030] In some preferred embodiments, the first fixed support plate 121 includes a horizontal portion that matches the second fixed support plate 122 and an inclined portion for rotatably connecting with the first bracket 110. Specifically, the horizontal portion and the first fixed support plate 121 are parallel to stably clamp the high-temperature ceramic rod and fix it securely. Furthermore, the horizontal portion and the mating portion 111 tend to be parallel in the installed state. Since the adjustment rotation angle is small, the relative swing angle of the first bracket 110 and the second bracket 120 is extremely small. The mating portion 111 of the first bracket 110 and the horizontal portion of the second bracket 120 tend to be parallel, making the adjustment more stable.

[0031] In some preferred embodiments, the bottom of the horizontal section and the top of the second fixed support plate 122 are respectively provided with a second mating structure 124 for engaging with the side wall of the second high-temperature ceramic rod 320. The second mating structure 124 is a second arc-shaped groove, which has the same function as the first arc-shaped groove, and is used to abut against the side wall of the second high-temperature ceramic rod 320 to accommodate and cover the second high-temperature ceramic rod 320, increase the mating area, and ensure the stability of the adjustment process.

[0032] In some embodiments, reference Figure 5 and Figure 6 Alternatively, the adjustment mechanism 200 may include an adjustment screw 210, which is threadedly connected to the second bracket 120 and axially limited to the first bracket 110. The small end of the adjustment screw 210 is spherical, allowing it to be axially limited to the first bracket 110 and have the freedom of circumferential rotation. By rotating the adjustment screw 210 clockwise or counterclockwise, the angles of the first bracket 110 and the second bracket 120 can be adjusted, thereby adjusting the strain value. In other embodiments, the adjustment mechanism 200 may also include an adjustment screw 210, which is threadedly connected to the first bracket 110 and axially limited to the second bracket 120.

[0033] It should be understood that in actual use, the positions of the first bracket 110 and the second bracket 120 can be interchanged. That is, the first bracket 110 can also cooperate with the second high-temperature ceramic rod 320 located below, and the second bracket 120 can also cooperate with the first high-temperature ceramic rod 310 located above.

[0034] On the other hand, this embodiment also provides a strain fine-tuning method for a high-temperature strain fatigue extensometer 300, applied to the aforementioned high-temperature strain fatigue extensometer 300 strain fine-tuning device. The fine-tuning method includes: S1. Security check; Specifically, ensure that the testing machine has been stopped and the load has been reduced to zero; and confirm the integrity of each component, checking the clamping mechanism 100, the adjusting mechanism, and the high-temperature ceramic rod of the extensometer 300. S2. Install the extensometer 300; correctly install the extensometer 300 onto the specimen; S3. Confirm the direction of the problem and select the adjustment direction; before operation, clarify whether the strain value after temperature fixation "decreases" or "increases", and then select the correct adjustment direction. The wrong direction will aggravate the reading deviation. Specifically, the adjustment direction of the adjustment mechanism 200 is matched and adjusted according to the trend of strain value change after heat preservation; taking the first bracket 110 and the first high-temperature ceramic rod 310 as an example, when the strain value decreases after heat preservation, the first bracket 110 is placed above the first high-temperature ceramic rod 310 during installation, and when the strain value increases after heat preservation, the first bracket 110 is placed below the first high-temperature ceramic rod 310 during installation. S4. Install the clamping mechanism 100 and the adjusting mechanism 200; Specifically, the first fixed support plate 121 and the second fixed support plate 122 are installed to the second high-temperature ceramic rod 320 and locked and fixed by locking screws, and the first bracket 110 is kept in a freely adjustable state; S5. Based on the real-time strain reading, the fulcrum position of the first high-temperature ceramic rod 310 and / or the second high-temperature ceramic rod 320 is finely adjusted by the adjustment mechanism 200 until the strain value reading meets the requirements; Step S5 includes: S51. Temperature begins to rise; S52. Maintain heat after heating; S53. When the load on the testing machine is zero, the fulcrum position of the first high-temperature ceramic rod 310 and / or the second high-temperature ceramic rod 320 is finely adjusted via the adjustment mechanism 200 according to the real-time strain reading until the strain value reading meets the requirements. Specifically, when the "strain value decreases" after heat preservation, the adjusting screw 210 should be turned clockwise slightly while closely observing the real-time strain reading on the computer. The screw should be turned slowly and slightly until the excessive strain value decreases and returns to zero or the required initial value, that is, the strain value displayed by the computer software is as close to zero as possible. When the "strain value increases" after heat preservation, the adjustment should be turned counterclockwise according to its installation direction. It should be noted that all adjustments must be made when the testing machine load is zero; otherwise, it will lead to serious data distortion and may damage the extensometer. The adjustment of the adjusting screw should be very small, and should be made in small angle increments (such as 15-30 degrees) each time, and the changes in the reading should be observed. S6. After the strain stabilizes, remove the adjustment device; specifically, gently reverse the adjustment screw 210 and then remove the adjustment device.

[0035] S7. Conduct the experiment.

[0036] On the other hand, a preferred embodiment of the present invention also provides a method for fine-tuning the strain of a high-temperature strain fatigue extensometer, which uses the above-mentioned high-temperature strain fatigue extensometer strain fine-tuning device.

[0037] Example 1 In the high-temperature strain fatigue test of this embodiment, the strain fine-tuning device of this preferred embodiment is used to adjust the original gauge length at 500℃. Specifically: the strain fatigue test is conducted at a high temperature of 500℃ for adjustment. After holding at this temperature, the strain reading is -0.120%. Figure 2 or Figure 5 The installation method shown in the diagram involves gently rotating the adjusting screw 2 clockwise until the strain reaches -0.002% and stabilizes, then removing the device. The strain display value is -0.003%, and the adjustment process is stable.

[0038] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A strain fine-tuning device for a high-temperature strain fatigue extensometer, the extensometer (300) comprising a first high-temperature ceramic rod (310) and a second high-temperature ceramic rod (320) distributed vertically, characterized in that, The strain fine-tuning device includes: The clamping mechanism (100) includes a first bracket (110) for cooperating with the first high-temperature ceramic rod (310) and a second bracket (120) for cooperating with the second high-temperature ceramic rod (320). The first bracket (110) and the second bracket (120) are rotatably connected. The second bracket (120) includes a first fixed support plate (121) and a second fixed support plate (122) and a locking member (123) for connecting the first fixed support plate (121) and the second fixed support plate (122). The first fixed support plate (121) is used to clamp the second high-temperature ceramic rod (320) from above, and the second fixed support plate (122) is used to clamp the second high-temperature ceramic rod (320) from below. The locking member (123) is used to lock and fix the first fixed support plate (121) and the second fixed support plate (122). An adjustment mechanism (200) is used to mount the clamping mechanism (100) and to drive the first bracket (110) and the second bracket (120) to swing relative to each other at a preset angle based on the hinge point between them, thereby acting on the first high-temperature ceramic rod (310) and the second high-temperature ceramic rod (320) respectively. The adjustment mechanism (200) includes an adjustment screw (210), which passes through the first bracket (110) and is threadedly connected to the second bracket (120), or the adjustment screw (210) passes through the second bracket (120) and is threadedly connected to the first bracket (110). The adjustment screw (210) is fitted with an elastic element (220) located between the first bracket (110) and the second bracket (120), the two ends of which are used to act on the first bracket (110) and the second bracket (120) respectively. The first bracket (110) includes a mating part (111) and a connecting part (112). The top and bottom of the mating part (111) are respectively provided with a first mating structure (113) for mating with the first high-temperature ceramic rod (310). The connecting part (112) is used to rotatably connect with the second bracket (120). The end of the connecting part (112) protrudes towards the second bracket (120) to form a protrusion for installing the adjusting screw (210), so that the axis of the adjusting screw (210) is perpendicular to the axis of the first high-temperature ceramic rod (310).

2. The high-temperature strain fatigue extensometer strain trim device of claim 1, wherein, The first mating structure (113) includes a first arc-shaped groove formed in the first bracket (110), the radial dimension of the first arc-shaped groove being larger than the radial dimension of the first high-temperature ceramic rod (310); the first arc-shaped groove is used to abut against the side wall of the first high-temperature ceramic rod (310).

3. The high-temperature strain fatigue extensometer strain trim device of claim 1, wherein, The first fixed support plate (121) includes a horizontal portion that matches the second fixed support plate (122) and an inclined portion for rotatably connecting with the first bracket (110).

4. The high-temperature strain fatigue extensometer strain trim device of claim 1, wherein, The adjustment mechanism (200) includes an adjustment screw (210), which is threaded to the first bracket (110) and axially limited to the second bracket (120), or the adjustment screw (210) is threaded to the second bracket (120) and axially limited to the first bracket (110).

5. A method of fine tuning of strain in a high temperature strain fatigue extensometer, characterized by, The strain fine-tuning device for a high-temperature strain fatigue extensometer according to any one of claims 1-4 includes the following fine-tuning method: S1. Security check; S2. Install the extensometer; S3. Confirm the problem direction and select the adjustment direction; S4. Install the clamping mechanism and adjustment mechanism; S5. Based on the real-time strain reading, the fulcrum position of the first high-temperature ceramic rod and / or the second high-temperature ceramic rod is finely adjusted by the adjustment mechanism until the strain value reading meets the requirements; S6. After the strain stabilizes, remove the adjustment device; S7. Conduct the experiment.

6. The high-temperature strain fatigue extensometer strain trimming method of claim 5, wherein, Step S3 includes: adjusting the direction of the adjustment mechanism according to the trend of strain value change after heat preservation.

7. The high-temperature strain fatigue extensometer strain trimming method of claim 5, wherein, Step S5 includes: S51. Temperature begins to rise; S52. Maintain heat after heating; S53. When the load on the testing machine is zero, the fulcrum position of the first high-temperature ceramic rod and / or the second high-temperature ceramic rod is finely adjusted by the adjustment mechanism based on the real-time strain reading until the strain value reading meets the requirements.

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