Thermal mechanical analyzer test fixture and thermal testing method

Abstract

The present invention discloses a fixture for testing a thermomechanical analyzer, which includes a base, a pressure block and two clamping blocks; the upper ends of the left and right vertical columns of the U-shaped base are arc surfaces with the same diameter; the axis of the arc surface is the front-to-back direction; the curvature of the arc surface is greater than 180°; W≤D, D is the diameter of the arc surface, and W is the left-right width at the lower ends of the left and right vertical columns; the pressure block is semi-cylindrical; 0.8S≤d≤S, d is the diameter of the semi-cylinder, and S is the minimum distance between the two arc surfaces at the upper ends of the left and right vertical columns; the two clamping blocks are used to be installed and fixed to the left and right ends of the bottom horizontal column, and the two ends of the strip sample are respectively fixed to the left and right ends of the bottom horizontal column. The present invention also discloses a thermal testing method using the fixture for testing a thermomechanical analyzer. The present invention enables the compression measuring probe and sample carrier of the thermomechanical analyzer to complete the measurement of the tension of the strip sample, thereby reducing equipment cost and replacement times, and ensuring accurate measurement results.

Description

Technical Field

[0001] The present invention relates to a thermal analysis test technology, and in particular to a fixture for testing a thermomechanical analyzer (TMA) and a thermal testing method. Background Art

[0002] Thermomechanical Analyzer (TMA) is a device that measures the deformation of a material as a function of temperature and time under programmed temperature and non-vibration load. It can measure parameters such as the thermal expansion coefficient and phase transition temperature of the material.

[0003] Commercial thermomechanical analyzers (TMAs) are equipped with different probes and stages to accommodate different testing scenarios. The probes and stages for measuring sample tension and compression are different, requiring a separate set to perform both tests, and they need to be replaced between tests. Furthermore, a single set of probes and stages is very expensive. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to enable the compression measuring probe and sample carrier of the thermomechanical analyzer to complete the measurement of the tension of the strip sample, thereby reducing the equipment cost and the number of replacements and making the measurement results accurate.

[0005] In order to solve the above technical problems, the present invention provides a test fixture for a thermomechanical analyzer, which includes a base 1, a pressing block 2 and two clamping blocks 3;

[0006] The base 1 is U-shaped and includes a bottom horizontal column 10, a left vertical column 11 and a right vertical column 12;

[0007] The lower end of the left vertical column 11 is vertically fixed to the left end of the bottom horizontal column 10;

[0008] The lower end of the right vertical column 11 is vertically fixed to the right end of the bottom horizontal column 10;

[0009] The upper ends of the left vertical column 11 and the right vertical column 12 are arc surfaces with the same diameter;

[0010] The axis of the arc surface is the front-back direction;

[0011] The left end of the arc surface at the upper end of the left vertical column 11 is tangent to the left side surface of the left vertical column 11;

[0012] The right end of the arc surface at the upper end of the right vertical column 12 is tangent to the right side of the right vertical column 11;

[0013] The arc of the arc surface is greater than 180°;

[0014] W≤D≤1.5W, D is the diameter of the arc surface, and W is the left and right widths at the lower ends of the left vertical column 11 and the right vertical column 12;

[0015] The pressing block 2 is semi-cylindrical; 0.8S≤d≤S, d is the diameter of the semi-cylinder, and S is the minimum distance between the two arc surfaces at the upper ends of the left vertical column 11 and the right vertical column 12;

[0016] The two clamping blocks 3 are used to be installed and fixed to the left and right ends of the bottom horizontal column 10 , and to fix the two ends of the strip sample 4 to the left and right ends of the bottom horizontal column 10 respectively.

[0017] Preferably, 0.1L≤W≤0.3L, where L is the left-right length of the bottom horizontal column 10 .

[0018] Preferably, the left side surface of the left vertical column 11 is flush with the left end surface of the bottom horizontal column 10;

[0019] The right side surface of the right vertical column 12 is flush with the right end surface of the bottom horizontal column 10.

[0020] Preferably, the left side of the left vertical column 11 protrudes 0.1mm to 10mm to the left of the left end surface of the bottom horizontal column 10;

[0021] The right side of the right vertical column 12 protrudes 0.1 mm to 10 mm from the right side of the right end surface of the bottom horizontal column 10 .

[0022] Preferably, the right end of the arc surface at the upper end of the left vertical column 11 is located on the right side of the left vertical column 11;

[0023] The left end of the arc surface at the upper end of the right vertical column 12 is located on the left side of the right vertical column 11 .

[0024] Preferably, the distances from the right end of the arc surface at the upper end of the left vertical column 11 and the left end of the arc surface at the upper end of the right vertical column 12 to the upper side surface of the bottom horizontal column 10 are greater than d.

[0025] Preferably, d=S.

[0026] Preferably, the distances between the axis of the arc surface at the upper end of the left vertical column 11 and the axis of the arc surface at the upper end of the right vertical column 12 and the upper side surface of the bottom horizontal column 10 are equal.

[0027] Preferably, each clamping block 3 is formed with two through holes;

[0028] Two screw holes are correspondingly formed at the left end of the bottom horizontal column 10;

[0029] Two screw holes are correspondingly formed at the right end of the bottom horizontal column 10;

[0030] Pass the bolts through the through holes of the clamping blocks 3 and thread them into the screw holes on the left and right ends of the bottom horizontal column 10, so that the two clamping blocks 3 are installed and fixed to the left and right ends of the bottom horizontal column 10, and fix the two ends of the strip sample 4 to the left and right ends of the bottom horizontal column 10 respectively.

[0031] Preferably, the base 1 and the pressing block 2 are made of the same material.

[0032] Preferably, the thermal expansion coefficient of the material of the base 1 and the pressing block 2 is smaller than the thermal expansion coefficient of the strip sample 4 .

[0033] To solve the above technical problems, the present invention provides a thermal testing method using the above-mentioned thermal mechanical analyzer test fixture, wherein the thermal mechanical analyzer has a probe capable of measuring compression and a sample carrier, and the method comprises the following steps:

[0034] S1. Place the base 1 on the sample carrier of the thermomechanical analyzer;

[0035] S2. The strip sample 4 is attached to the arc surface of the upper end of the left vertical column 11 of the U-shaped base 1 and the arc surface of the upper end of the right vertical column 12, and the ends of the strip sample 4 are fixed to the left and right ends of the bottom horizontal column 10 by the clamp 3;

[0036] S3. The compact 2 is placed on the strip sample 4 between the upper arc surface of the left vertical column 11 and the right vertical column 12, and the semi-cylindrical surface of the compact 2 is in contact with the strip sample 4;

[0037] S4. The probe of the thermomechanical analyzer is pressed against the plane of the compact 2. Under the action of the gravity of the compact 2 and the downward pressure of the probe, the compact 2 pushes down the strip sample 4, so that the strip sample 4 is tightly attached to the arc surface of the upper end of the left vertical column 11, the arc surface of the upper end of the right vertical column 12 and the semi-cylindrical surface of the compact 2;

[0038] S5. Raise the temperature of the sample loading platform. When the strip sample 4 expands due to the heat, the pressing block 2 moves downward under the force. The probe moves downward accordingly. The displacement of the probe is detected and recorded.

[0039] Preferably, the strip sample 4 is long enough. In step S3, under the action of the gravity of the pressing block 2, the strip sample 4 is stretched tightly against the arc surface at the upper end of the left vertical column 11, the arc surface at the upper end of the right vertical column 12 and the semi-cylindrical surface of the pressing block 2, and the plane of the pressing block is located below the center of the arc surface at the upper end of the left vertical column 11 and the center of the arc surface at the upper end of the right vertical column 12.

[0040] Preferably, the linear expansion coefficient α of the strip sample 4 is:

[0041] Wherein, L is the original length of the strip sample; ΔT is the temperature change; ΔH is the probe displacement; L0 is the length of the profile of the fixture that affects the strip sample 4; α0 is the linear expansion coefficient of the fixture.

[0042] Preferably, α0=0.

[0043] Preferably, L0=L.

[0044] The present invention provides a thermomechanical analyzer (TMA) test fixture and thermal testing method. This fixture enables the compression-measuring probe and sample stage of a thermomechanical analyzer (TMA) to perform tensile measurements on strip samples without changing the relative positions of the probe and sample stage, thereby reducing equipment costs and the number of replacements. The fixture also overcomes the effects of airflow during testing, ensuring accurate measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 It is a three-dimensional schematic diagram of an embodiment of a test fixture for a thermomechanical analyzer of the present invention;

[0047] Figure 2 1 is a front view of an embodiment of a thermomechanical analyzer test fixture of the present invention.

[0048] Description of the accompanying drawings:

[0049] 1 base; 10 bottom horizontal column; 11 left vertical column; 12 right vertical column; 2 pressure block; 3 clamping block; 4 sample. DETAILED DESCRIPTION

[0050] 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0051] The terms "first", "second" and similar words used in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprises" and similar words mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", "front", "back" and the like are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0052] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other.

[0053] Example 1

[0054] like Figure 1 、 Figure 2 As shown, a thermomechanical analyzer (TMA) test fixture includes a base 1, a pressing block 2 and two clamping blocks 3;

[0055] The base 1 is U-shaped and includes a bottom horizontal column 10, a left vertical column 11 and a right vertical column 12;

[0056] The lower end of the left vertical column 11 is vertically fixed to the left end of the bottom horizontal column 10;

[0057] The lower end of the right vertical column 11 is vertically fixed to the right end of the bottom horizontal column 10;

[0058] The upper ends of the left vertical column 11 and the right vertical column 12 are arc surfaces with the same diameter;

[0059] The axis of the arc surface is the front-back direction;

[0060] The left end of the arc surface at the upper end of the left vertical column 11 is tangent to the left side surface of the left vertical column 11;

[0061] The right end of the arc surface at the upper end of the right vertical column 12 is tangent to the right side of the right vertical column 11;

[0062] The arc angle of the arc surface is greater than 180° and less than 270°;

[0063] W≤D≤1.5W, D is the diameter of the arc surface, and W is the left and right widths at the lower ends of the left vertical column 11 and the right vertical column 12;

[0064] The pressing block 2 is semi-cylindrical; 0.8S≤d≤S, d is the diameter of the semi-cylinder, and S is the minimum distance between the two arc surfaces at the upper ends of the left vertical column 11 and the right vertical column 12;

[0065] The two clamping blocks 3 are used to be installed and fixed to the left and right ends of the bottom horizontal column 10 , and to fix the two ends of the strip sample 4 to the left and right ends of the bottom horizontal column 10 respectively.

[0066] The first embodiment of the thermomechanical analyzer (TMA) test fixture enables the compression-measuring probe and sample stage of the thermomechanical analyzer (TMA) to perform tensile measurements on strip samples without changing the relative positions of the probe and sample stage, thereby reducing equipment costs and the number of replacements. The fixture also overcomes the effects of airflow during testing, ensuring accurate measurement results.

[0067] Example 2

[0068] Based on the thermomechanical analyzer (TMA) test fixture of the first embodiment, 0.1L≤W≤0.3L, where L is the left-right length of the bottom horizontal column 10 .

[0069] Preferably, the left side surface of the left vertical column 11 is flush with the left end surface of the bottom horizontal column 10 ; the right side surface of the right vertical column 12 is flush with the right end surface of the bottom horizontal column 10 .

[0070] Preferably, the left side of the left vertical column 11 protrudes 0.1mm to 10mm from the left side of the left end surface of the bottom horizontal column 10; the right side of the right vertical column 12 protrudes 0.1mm to 10mm from the right side of the right end surface of the bottom horizontal column 10.

[0071] Example 3

[0072] Based on the thermomechanical analyzer (TMA) test fixture of the first embodiment, the right end of the arc surface at the upper end of the left vertical column 11 is located on the right side of the left vertical column 11;

[0073] The left end of the arc surface at the upper end of the right vertical column 12 is located on the left side of the right vertical column 11 .

[0074] Preferably, the distances between the axis of the arc surface at the upper end of the left vertical column 11 and the axis of the arc surface at the upper end of the right vertical column 12 and the upper side surface of the bottom horizontal column 10 are equal.

[0075] Example 4

[0076] Based on the thermomechanical analyzer (TMA) test fixture of the first embodiment, the distance from the right end of the arc surface of the upper end of the left vertical column 11 and the left end of the arc surface of the upper end of the right vertical column 12 to the upper side surface of the bottom horizontal column 10 is greater than d.

[0077] Preferably, d = S

[0078] Example 5

[0079] Based on the thermomechanical analyzer (TMA) test fixture of the first embodiment, two through holes are formed on each clamping block 3;

[0080] Two screw holes are correspondingly formed at the left end of the bottom horizontal column 10;

[0081] Two screw holes are correspondingly formed at the right end of the bottom horizontal column 10;

[0082] Pass the bolts through the through holes of the clamping blocks 3 and thread them into the screw holes on the left and right ends of the bottom horizontal column 10, so that the two clamping blocks 3 are installed and fixed to the left and right ends of the bottom horizontal column 10, and fix the two ends of the strip sample 4 to the left and right ends of the bottom horizontal column 10 respectively.

[0083] Preferably, the base 1 and the pressing block 2 are made of the same material.

[0084] Preferably, the thermal expansion coefficient of the material of the base 1 and the pressing block 2 is smaller than the thermal expansion coefficient of the strip sample 4 .

[0085] Example 6

[0086] The thermal testing method using the thermomechanical analyzer (TMA) test fixture of Example 1, wherein the thermomechanical analyzer (TMA) has a probe capable of measuring compression and a sample stage, includes the following steps:

[0087] S1. Place the base 1 on the sample stage (Stage) of the thermomechanical analyzer (TMA);

[0088] S2. The strip sample 4 is attached to the arc surface of the upper end of the left vertical column 11 of the U-shaped base 1 and the arc surface of the upper end of the right vertical column 12, and the ends of the strip sample 4 are fixed to the left and right ends of the bottom horizontal column 10 by the clamp 3;

[0089] S3. The compact 2 is placed on the strip sample 4 between the upper arc surface of the left vertical column 11 and the right vertical column 12, and the semi-cylindrical surface of the compact 2 is in contact with the strip sample 4;

[0090] S4. The probe of the thermomechanical analyzer (TMA) is pressed against the plane of the compact 2. Under the action of the gravity of the compact 2 and the downward pressure of the probe, the compact 2 pushes down the strip sample 4, so that the strip sample 4 is tightly attached to the arc surface of the upper end of the left vertical column 11, the arc surface of the upper end of the right vertical column 12, and the semi-cylindrical surface of the compact 2;

[0091] S5. Raise the temperature of the sample stage. When the strip sample 4 expands due to the heat, the pressing block 2 moves downward under the force. The probe moves downward accordingly. The displacement of the probe is detected and recorded.

[0092] Preferably, the strip sample 4 is long enough. In step S3, under the action of the gravity of the pressing block 2, the strip sample 4 is stretched tightly against the arc surface at the upper end of the left vertical column 11, the arc surface at the upper end of the right vertical column 12 and the semi-cylindrical surface of the pressing block 2, and the plane of the pressing block is located below the center of the arc surface at the upper end of the left vertical column 11 and the center of the arc surface at the upper end of the right vertical column 12.

[0093] The sixth embodiment is a thermal testing method of a fixture for a thermomechanical analyzer (TMA). The thermomechanical analyzer (TMA) has a probe for measuring compression and a sample carrier. The sample and the fixture are placed on the sample carrier. The surfaces in contact with the strip sample 4 are smooth and standard flat and curved surfaces. The strip sample 4 is thermally tested using the probe for measuring compression and the sample carrier to obtain accurate thermal testing results.

[0094] Example 7

[0095] Based on the thermal testing method of Example 6, the linear expansion coefficient α of the strip sample 4 is:

[0096]

[0097] Among them, ΔL is the change in the length of the strip sample, an unknown quantity; L is the original length of the sample, a known quantity; ΔT is the temperature change, a known quantity; ΔL0 is the effect of the fixture expansion, an unknown quantity; ΔH is the probe displacement, a test quantity; L0 is the length of the contour of the fixture that affects the strip sample 4, a known quantity; α0 is the linear expansion coefficient of the fixture, a known quantity.

[0098] Under ideal conditions, the thermal expansion coefficient of the materials used for the base 1 and the pressing block 2 is set to 0, α0 = 0, and the above formula can be simplified to:

[0099] In fact, the thermal expansion coefficient of the materials used for the base 1 and the pressing block 2 cannot be 0, and L0≈L. The above formula can be simplified to:

[0100] The calculation formula for the linear expansion coefficient α of the strip sample 4 can be built into the test processing software.

[0101] The thermal testing method of the thermomechanical analyzer (TMA) test fixture of the seventh embodiment takes into account the thermal expansion coefficient of the fixture material and can obtain a more accurate linear thermal expansion coefficient of the strip sample.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fixture for testing a thermomechanical analyzer, characterized in that: It comprises a base (1), a pressing block (2) and two clamping blocks (3); The base (1) is U-shaped and comprises a bottom horizontal column (10), a left vertical column (11) and a right vertical column (12); The lower end of the left vertical column (11) is vertically fixed to the left end of the bottom horizontal column (10); The lower end of the right vertical column (12) is vertically fixed to the right end of the bottom horizontal column (10); The upper ends of the left vertical column (11) and the right vertical column (12) are arc surfaces with the same diameter; The axis of the arc surface is the front-back direction; The left end of the arc surface at the upper end of the left vertical column (11) is tangent to the left side of the left vertical column (11); The right end of the arc surface at the upper end of the right vertical column (12) is tangent to the right side of the right vertical column (12); The arc of the arc surface is greater than 180 0 ; W≤D, D is the diameter of the arc surface, and W is the left-right width at the lower ends of the left vertical column (11) and the right vertical column (12); The pressing block (2) is semi-cylindrical; 0.8S≤d≤S, d is the diameter of the semi-cylinder, and S is the minimum distance between the two arc surfaces at the upper ends of the left vertical column (11) and the right vertical column (12); The two clamping blocks (3) are used to be installed and fixed to the left and right ends of the bottom cross column (10), and to fix the two ends of the strip sample (4) to the left and right ends of the bottom cross column (10) respectively.

2. The test fixture for thermomechanical analyzer according to claim 1, characterized in that: The arc of the arc surface is greater than 180 0 and less than 270 0 ; W≤D≤1.5W; 0.1L≤W≤0.3L, L is the left and right length of the bottom horizontal column (10); The left side of the left vertical column (11) is flush with the left end surface of the bottom horizontal column (10); The right side of the right vertical column (12) is flush with the right end surface of the bottom horizontal column (10); or, The left side of the left vertical column (11) protrudes 0.1mm to 10mm from the left side of the left end surface of the bottom horizontal column (10); The right side of the right vertical column (12) protrudes 0.1mm to 10mm toward the right side of the right end surface of the bottom horizontal column (10).

3. The test fixture for thermomechanical analyzer according to claim 1, characterized in that: The right end of the arc surface at the upper end of the left vertical column (11) is located on the right side of the left vertical column (11); The left end of the arc surface at the upper end of the right vertical column (12) is located on the left side of the right vertical column (12).

4. The test fixture for thermomechanical analyzer according to claim 1, characterized in that: The distances from the right end of the arc surface at the upper end of the left vertical column (11) and the left end of the arc surface at the upper end of the right vertical column (12) to the upper side surface of the bottom horizontal column (10) are greater than d.

5. The test fixture for thermomechanical analyzer according to claim 1, characterized in that: The distances between the axis of the arc surface at the upper end of the left vertical column (11) and the axis of the arc surface at the upper end of the right vertical column (12) and the upper side surface of the bottom horizontal column (10) are equal.

6. The test fixture for thermomechanical analyzer according to claim 1, characterized in that: Each clamping block (3) is formed with two through holes; Two screw holes are correspondingly formed at the left end of the bottom horizontal column (10); Two screw holes are correspondingly formed at the right end of the bottom horizontal column (10); The bolts are passed through the through holes of the clamping blocks (3) and threadedly fixed to the screw holes at the left and right ends of the bottom horizontal column (10), so that the two clamping blocks (3) are installed and fixed to the left and right ends of the bottom horizontal column (10), and the two ends of the strip sample (4) are respectively fixed to the left and right ends of the bottom horizontal column (10).

7. The test fixture for a thermomechanical analyzer according to claim 1, characterized in that: The base (1) and the pressing block (2) are made of the same material; The thermal expansion coefficient of the material of the base (1) and the pressing block (2) is smaller than the thermal expansion coefficient of the strip sample (4).

8. A thermal testing method using the test fixture for a thermomechanical analyzer according to any one of claims 1 to 7, wherein the thermomechanical analyzer has a probe capable of measuring compression and a sample stage, wherein: The following steps are involved: S1. Place the base (1) on the sample carrier of the thermomechanical analyzer; S2. Attach the strip sample (4) to the arc surface of the upper end of the left vertical column (11) and the arc surface of the upper end of the right vertical column (12) of the U-shaped base (1), and fix the ends of the strip sample (4) to the left and right ends of the bottom horizontal column (10) through the clamping block (3); S3. The pressing block (2) is placed on the strip sample (4) between the upper arc surfaces of the left vertical column (11) and the right vertical column (12), so that the semi-cylindrical surface of the pressing block (2) contacts the strip sample (4); S4. Press the probe of the thermomechanical analyzer against the plane of the pressing block (2). Under the action of the gravity of the pressing block (2) and the downward pressure of the probe, the pressing block (2) pushes down the strip sample (4), so that the strip sample (4) is tightly attached to the arc surface of the upper end of the left vertical column (11), the arc surface of the upper end of the right vertical column (12), and the semi-cylindrical surface of the pressing block (2); S5. Raise the temperature of the sample carrier. When the strip sample (4) expands due to the heat, the pressing block (2) is forced to move downward, and the probe moves downward accordingly. The displacement of the probe is detected and recorded.

9. The thermal testing method according to claim 8, characterized in that: The strip sample (4) is long enough. In step S3, under the action of the gravity of the pressing block (2), the strip sample (4) is stretched tightly against the arc surface of the upper end of the left vertical column (11), the arc surface of the upper end of the right vertical column (12) and the semi-cylindrical surface of the pressing block (2), and the plane of the pressing block is located below the center of the arc surface of the upper end of the left vertical column (11) and the center of the arc surface of the upper end of the right vertical column (12).

10. The thermal testing method according to claim 8, wherein: The linear expansion coefficient α of the strip sample (4) is: Wherein, L is the original length of the strip sample; ΔT is the temperature change; ΔH is the probe displacement; L0 is the length of the profile of the fixture that affects the strip sample (4); α0 is the linear expansion coefficient of the fixture.

Images