A test tool for testing the thermal expansion coefficient of a hard sheet material
By improving the gasket structure to a support block design, the thermal expansion coefficient of rigid thin sheet samples can be tested, solving the problem that existing testing fixtures cannot test thin sheet samples, expanding the range of applicable samples and improving testing accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 泛锐云智科技(郑州)有限公司
- Filing Date
- 2025-06-20
- Publication Date
- 2026-07-21
AI Technical Summary
Existing thermal expansion coefficient testing fixtures are insufficient to meet the testing requirements of rigid, thin sheet-like samples, and cannot achieve centered contact between the push rod and the sheet sample, thus preventing the test from being performed.
The existing gasket structure has been improved to a support block design with a sampling hole and a through groove. When it is suitable for cylindrical samples, it is placed horizontally in the sampling hole for support, and when it is suitable for sheet-like samples, it is placed horizontally in the through groove for support. The combination of positioning rod and positioning hole limits the alignment of the support block to meet the centering requirements of the push rod and the sample.
The range of test samples has been expanded, ensuring the accuracy of thermal expansion coefficient testing for sheet-like samples, avoiding the problem of increased thermal expansion resistance caused by misalignment of support blocks, and improving the accuracy of test results.
Smart Images
Figure CN224535864U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of material thermal expansion coefficient testing technology, specifically relating to a tooling for testing the thermal expansion coefficient of rigid thin sheet materials. Background Technology
[0002] The coefficient of thermal expansion is a key physical parameter characterizing the dimensional stability of a material under temperature changes. It has important application value in the field of materials science and engineering, especially for high-temperature materials in aerospace, nuclear energy engineering, petrochemical and new energy fields. The test temperature for their thermal expansion performance is as high as 1000℃, or even as high as 2300℃. Accurately measuring the thermal expansion behavior of materials at extreme temperatures is of great significance for ensuring the long-term safe operation and performance stability of equipment.
[0003] The push rod method is the most classic method for measuring the coefficient of thermal expansion of materials. It uses mechanical principles to measure the coefficient of thermal expansion. One end of the sample is placed in contact with the end of the sample holder, and the other end is in contact with the push rod. The sample, sample holder, and push rod are placed in a high-temperature furnace and heated. The difference in thermal expansion between the sample and these components is transmitted by the push rod and measured by the displacement measurement system, thereby obtaining the coefficient of thermal expansion of the material being measured.
[0004] Currently, the sample holder commonly used in testing equipment is a horizontally placed cylindrical shape. The push rod is located inside the sample holder. One end of the push rod is telescopically fixed to the end of the sample holder away from the high-temperature furnace and connected to the displacement measurement system. The other end of the push rod is used to center and abut against the sample to be tested during the test and to transmit the thermal expansion difference of the sample to the displacement measurement system. Therefore, ensuring that the push rod and the end of the sample are aligned and abut against each other during the test is one of the keys to achieving sample testing.
[0005] For samples with relatively small thickness that are difficult to align with the push rod for testing, shims are often used to elevate and simply limit the sample. The sample is placed on the shim to raise it so that it is aligned with the push rod for testing. However, existing shims are block structures with arc-shaped grooves on the surface, which are only suitable for relatively thick cylindrical samples. For hard, thin, high-temperature material samples such as single crystal wafers, fiber-reinforced ceramics, quartz-doped or other doped materials, and metal matrix composites, because the samples are thin, if they are placed flat on the shim, the push rod will still be above the thin sample because the height of the push rod is located at the center of the sample holder. During testing, the push rod cannot contact the thin sample, making thermal expansion testing impossible. Therefore, existing testing fixtures are insufficient to meet the testing requirements for thin samples. Summary of the Invention
[0006] To address the problem that existing thermal expansion coefficient testing fixtures are insufficient for testing rigid sheet-like samples, this invention proposes a thermal expansion coefficient testing fixture for rigid sheet materials. By improving the existing gasket structure, the improved testing fixture is applicable not only to testing conventional cylindrical samples but also to testing rigid sheet-like samples, thus expanding the range of test samples.
[0007] Based on the above objectives, the technical solution adopted in this application is as follows: A fixture for testing the coefficient of thermal expansion of a rigid thin sheet material includes a cylindrical sample holder and a push rod fixed inside the sample holder, the push rod being coaxial with the sample holder. The fixture also includes a first support block and a second support block adapted to the sample holder. Both the first and second support blocks have a sample placement hole, which is coaxial with the push rod when the first and second support blocks are placed in the sample holder for sample testing. Both the first and second support blocks also have two through slots, the openings of which communicate with the sample placement hole. The two through slots are distributed perpendicular to the sample placement hole.
[0008] Existing gasket structures are only suitable for testing the coefficient of thermal expansion of conventional cylindrical samples and cannot be used to test sheet-like samples. This application improves the existing gasket structure into a sample support block with a sampling hole and a through-slot structure. When the test sample is cylindrical, the cylindrical sample can be placed horizontally in the sampling holes of the first and second support blocks, providing stable support for both ends of the cylindrical sample. When the test sample is a rigid sheet, the sheet is placed horizontally and upright in the through-slot, and the through-slot structures of the first and second support blocks are used to support both ends of the sheet. The horizontally and upright sheet is located on the vertical centerline of the sampling hole, meeting the alignment requirements between the push rod and the sample during the test, thus enabling the testing of sheet-like samples. The testing fixture of this application is not only suitable for testing the coefficient of thermal expansion of conventional cylindrical samples but also for testing rigid sheet-like samples, expanding the range of test samples.
[0009] Furthermore, a positioning rod is fixed on the first support block, and a positioning hole that cooperates with the positioning rod is opened on the second support block.
[0010] Existing gaskets are independent structures. During testing, two gaskets are placed in appropriate positions within the sample holder to support the ends of the sample. However, placing the two independent gaskets separately in the sample holder can lead to misalignment, increasing the resistance to thermal expansion and affecting the accuracy of the test results. This application utilizes positioning rods and positioning holes to limit the combination of the first and second support blocks. When the first and second support blocks are then placed together in the sample holder, horizontal alignment is ensured, avoiding the problem of increased thermal expansion resistance due to misalignment, which could lead to inaccurate test results.
[0011] Furthermore, the axis of the positioning rod is parallel to the axis of the lofting hole, and the positioning rods are symmetrically distributed on the first support block.
[0012] The purpose of using positioning rods parallel to the axis of the lofting holes and symmetrically distributed positioning rods is to ensure the centering alignment of the lofting holes on the two support blocks when limiting their positions, and to improve the centering stability of the two support blocks during high-temperature testing.
[0013] Furthermore, the number of positioning holes and positioning rods is the same, either 2 or 4.
[0014] The positioning holes and positioning rods appear in pairs and are symmetrically distributed, which helps to improve the centering and limiting stability of the two support blocks, while avoiding too many limiting structures, which would make it inconvenient to pick up and lay out the samples.
[0015] Furthermore, the four corners of the outer sides of the first and second support blocks are all chamfered. When the first or second support block is placed in the sample holder, the two protruding edges at the bottom chamfers of the first and second support blocks are in contact with the inner wall of the sample holder.
[0016] Since the sample holder is cylindrical with an arc-shaped inner wall, the above-mentioned structural design of the two support blocks helps to further improve the contact stability between the support blocks and the sample holder.
[0017] Compared with the prior art, the technical effects of this application are as follows: This application improves the structure of the gasket in the existing thermal expansion coefficient testing fixture by modifying the structure of the support block. The improved support block has a circular layout hole and a through groove. At the same time, the two support blocks have a matching limiting structure, which makes the improved testing fixture suitable not only for testing cylindrical samples, but also for testing sheet-like samples, thus expanding the range of test samples. The limiting structure helps to align the two support blocks, avoiding thermal expansion resistance caused by human misalignment of the layout, and further improving the accuracy of the test results. Attached Figure Description
[0018] Figure 1 A schematic diagram of an existing thermal expansion coefficient testing fixture; Figure 2 A schematic diagram of an existing thermal expansion coefficient testing fixture; Figure 3 This is a schematic diagram of an existing gasket structure; Figure 4 This is a schematic diagram of the structure of the first gasket in Example 1; Figure 5 This is a schematic diagram of the structure of the second gasket in Example 1; Figure 6 This is a structural diagram of the combined state of the first gasket and the second gasket in Example 1; Figure 7 This is a diagram showing the combined state of the first and second gaskets sample holders in Example 1. Figure 8 This is a partial view of the testing fixture for the cylindrical sample in Example 1; Figure 9 This is a partial view of the testing fixture for the sheet-like sample in Example 1.
[0019] In the figure: 1. Sample holder; 2. Push rod; 3. Sample; 4. Gasket; 5. Arc groove; 6. First support block; 601. Positioning rod; 7. Second support block; 701. Positioning hole; 8. Sample placement hole; 9. Through groove; 10. First protruding ridge; 11. Second protruding ridge. Detailed Implementation
[0020] To better illustrate the objectives, technical solutions, and advantages of this invention, the invention will be further described below with reference to specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Example 1
[0021] The structure of existing thermal expansion coefficient testing fixtures is as follows: Figures 1-3 As shown, the sample holder 1, push rod 2, high-temperature furnace, and displacement measurement system are used. The sample holder 1 has only a top opening for placing the sample, and its side ends are closed to limit the ends of the sample 3. By placing the sample 3 in the sample holder 1, the two ends of the sample 3 are initially in contact with the push rod 2 and the ends of the sample holder 1, respectively. During the high-temperature heating test, as the sample 3 thermally expands, the resulting deformation difference is transmitted by the push rod 2 to the displacement measurement system for measurement, thereby obtaining the coefficient of thermal expansion of the sample 3 to be tested.
[0022] Currently, the sample holder 1 in the testing fixture is cylindrical, which is suitable for measuring most samples (mostly cylindrical samples). With the emergence of new materials and structures, there is also a demand for testing the coefficient of thermal expansion of rigid sheet materials, but the existing testing fixture cannot test such sheet samples.
[0023] The existing gasket 4 has the following structure: Figure 3 As shown, a block with an arc-shaped groove 5 on its surface is only suitable for arc-shaped samples with a certain thickness, such as cylindrical or cylindrical samples. When such samples are placed on the pad 4, the test requirement of the sample aligning with the push rod 2 can be met. However, for hard, thin, high-temperature material samples such as single crystal wafers, fiber-reinforced ceramics, quartz-doped or other doped materials, and metal matrix composites, because the samples are thin, if they are placed directly on the pad 4, the push rod 2 will still be above the thin sample because its height is located at the center of the sample holder 1. During the test, the push rod 2 cannot contact the thin sample, and thermal expansion test cannot be performed. Therefore, the existing test fixture is difficult to meet the test requirements for thin samples.
[0024] Therefore, based on this requirement, this application improves the existing thermal expansion coefficient testing fixture, as follows: Figures 4-9 As shown, the testing fixture includes a cylindrical sample holder 1 and a push rod 2 fixed inside the sample holder 1. The push rod 2 is coaxial with the sample holder 1. This part of the structure is the same as the prior art. The main improvement of the test fixture in this application is the structure of the gasket 4 in the existing test fixture. Therefore, the test fixture in this application also includes a first support block 6 and a second support block 7 adapted to the sample holder 1. The first support block 6 and the second support block 7 are both provided with a sample placement hole 8. When the first support block 6 and the second support block 7 are placed in the sample holder 1 for sample testing, the sample placement hole 8 is coaxial with the push rod 2. The first support block 6 and the second support block 7 are also provided with two through slots 9. The opening end of the through slots 9 is connected to the sample placement hole 8. The two through slots 9 are distributed along the vertical direction of the sample placement hole 8.
[0025] The existing gasket 4 structure is only suitable for testing the coefficient of thermal expansion of conventional cylindrical samples and cannot be used to test sheet-like samples. This application improves the existing gasket 4 structure into a sample support block with a sample placement hole 8 and a through groove 9. When the test sample is a cylindrical sample, the cylindrical sample can be placed horizontally in the sample placement hole 8 of the first support block 6 and the second support block 7 to stably support both ends of the cylindrical sample. When the sample to be tested is a rigid sheet, the sheet sample is placed horizontally and upright in the through groove 9. The through groove 9 structure of the first support block 6 and the second support block 7 are used to support the two ends of the sheet sample. The sheet sample after being placed horizontally and upright is located on the vertical centerline of the sample placement hole 8, which meets the alignment requirements between the push rod 2 and the sample during the test, thus realizing the test of sheet-like samples. The test fixture of this application is not only suitable for testing the coefficient of thermal expansion of conventional cylindrical samples, but also suitable for testing rigid sheet-like samples, thus expanding the range of test samples.
[0026] The existing pads 4 are independent structures. During testing, two pads 4 are placed in appropriate positions within the sample holder 1 to support the ends of the sample. However, placing the two independent pads 4 separately in the sample holder can lead to misalignment, increasing resistance to thermal expansion of the sample and affecting the accuracy of the test results. To avoid this problem, the structure of the first support block 6 in this application is as follows: Figure 4 As shown, the structure of the second support block 7 is as follows: Figure 5 As shown, a positioning rod 601 is fixed on the first support block 6, and a positioning hole 701 is provided on the second support block 7 to cooperate with the positioning rod 601. The positioning rod 601 and the positioning hole 701, through their limiting structure, together limit the position of the first support block 6 and the second support block 7 (e.g., ...). Figure 6 After (as shown), the first support block 6 and the second support block 7 are combined and placed inside the sample holder 1 (as shown). Figure 7 As shown in the figure, this ensures that the two are horizontally aligned, avoiding the problem of increased thermal expansion resistance due to misalignment of the two, which would lead to inaccurate test results.
[0027] In the above-mentioned limiting structure, the axis of the positioning rod 601 is parallel to the axis of the lofting hole 8 and the positioning rod 601 is symmetrically distributed, so that when the two support blocks are limited, the lofting holes 8 on the two support blocks are aligned, and the alignment stability of the two support blocks is improved during the high temperature test.
[0028] The number of positioning holes 701 and positioning rods 601 appears in pairs and is symmetrically distributed, which helps to improve the centering and limiting stability of the two support blocks, while avoiding too many limiting structures, which would be inconvenient for picking and laying out operations. Therefore, the number of positioning holes 701 and positioning rods 601 is 2 or 4. In this embodiment, the number of positioning holes 701 and positioning rods 601 is 4.
[0029] Since the sample holder 1 is cylindrical with an arc-shaped inner wall, the two support blocks are designed using the above-described structure. To further improve the contact stability between the first support block 6 and the second support block 7 and the sample holder 1, the four corners of the outer surfaces of the first support block 6 and the second support block 7 are chamfered. When the first support block 6 or the second support block 7 is placed in the sample holder 1, the first protruding edge 10 and the second protruding edge 11 at the bottom chamfer of the first support block 6 and the second support block 7 are in contact with the inner wall of the sample holder 1. Since the first support block and the second support block are both symmetrical in the left and right and in the top and bottom, the protruding edges at the four chamfered corners of the first support block and the second support block can all fit in contact with the inner wall of the sample holder.
[0030] The testing fixture provided in this embodiment is used for testing cylindrical samples, such as... Figure 8As shown, a cylindrical sample is inserted into the sample placement holes 8 of the first support block 6 and the second support block 7, respectively supporting and limiting both ends of the cylindrical sample. When the test fixture of this embodiment is used for testing sheet-like samples, as... Figure 9 As shown, a sheet-like material is inserted sideways into the through slots 9 of the first support block 6 and the second support block 7. The upper and lower ends and the horizontal ends of the horizontally placed sheet-like material are limited by four through slots 9, so that the push rod 2 can contact the sheet-like material and transmit its deformation due to thermal expansion in the length direction, thereby testing the coefficient of thermal expansion of the sheet-like material. Therefore, the coefficient of thermal expansion testing fixture provided in this application is not only suitable for cylindrical samples, but also for sheet-like samples, expanding the range of samples that can be tested.
Claims
1. A fixture for testing the coefficient of thermal expansion of a rigid thin sheet material, comprising a cylindrical sample holder and a push rod fixed inside the sample holder, wherein the push rod is coaxial with the sample holder; characterized in that, The testing fixture also includes a first support block and a second support block adapted to the sample holder; both the first support block and the second support block are provided with a sample placement hole, and when the first support block and the second support block are placed in the sample holder for sample testing, the sample placement hole is coaxial with the push rod; both the first support block and the second support block are also provided with two through slots, and the opening ends of the through slots are connected to the sample placement hole; the two through slots are distributed along the vertical direction of the sample placement hole.
2. The fixture for testing the coefficient of thermal expansion of rigid thin sheet materials as described in claim 1, characterized in that, A positioning rod is fixed on the first support block, and a positioning hole that cooperates with the positioning rod is opened on the second support block.
3. The fixture for testing the coefficient of thermal expansion of rigid thin sheet materials as described in claim 2, characterized in that, The axis of the positioning rod is parallel to the axis of the lofting hole, and the positioning rod is symmetrically distributed on the first support block.
4. The fixture for testing the coefficient of thermal expansion of rigid thin sheet materials as described in claim 2, characterized in that, The number of positioning holes and positioning rods is the same, either 2 or 4.
5. The fixture for testing the coefficient of thermal expansion of rigid thin sheet materials as described in claim 1, characterized in that, The four corners of the outer sides of the first and second support blocks are all chamfered. When the first or second support block is placed in the sample holder, the two protruding edges at the bottom chamfers of the first and second support blocks are in contact with the inner wall of the sample holder.