A wedge-shaped clamp for tensile-torsional combined loading test

Abstract

This invention relates to a wedge-shaped clamp for tensile-torsional combined loading tests, belonging to the field of material mechanical property testing technology. It includes an annular locking outer cover, wedge-shaped clamping blocks, and a circular clamp base plate. The wedge-shaped clamping blocks have grooves inside that match the end configuration of the specimen. After the specimen is clamped, it can be embedded into the wedge-shaped groove inside the annular locking outer cover. The circular clamp base plate is locked to the annular locking outer cover by four T-screws. Axial pressure is applied to the wedge-shaped clamping blocks through the central disc of the circular clamp base plate, causing the two inclined surfaces of the wedge-shaped groove inside the annular locking outer cover to apply an inward preload to the wedge-shaped clamping blocks, ensuring that the specimen is firmly clamped before the start of monotonic tensile, monotonic torsion, and tensile-torsional combined loading tests. Its advantages include simple structure, convenient clamping, strong clamping force, good centering, and adaptability to specimens with various cross-sectional shapes, showing good application prospects in tensile-torsional combined loading tests.

Description

Technical Field

[0001] This invention relates to the field of material mechanical property testing technology, and in particular to a wedge clamp for tensile-torsion composite loading tests. It can be used with a tensile-torsion composite loading device to effectively and conveniently clamp the specimen in monotonic tension, monotonic torsion, and tensile-torsion composite loading tests, ensuring the reliability of the test results. Background Technology

[0002] Studying the elasto-plastic deformation and damage fracture mechanisms of materials under service conditions is of great significance for deeply revealing the service behavior, reliability, and life assessment of materials and their products. Since mechanical components in service are typically subjected to multiple loads simultaneously, traditional monotonic loading testing techniques such as uniaxial tension and in-plane torsion are insufficient to meet the needs of mechanical property analysis. Therefore, in recent years, academia and engineering have developed a series of composite loading testing methods, among which the tensile-torsion composite loading test is the most widely used. When conducting tensile-torsion composite loading tests, using appropriate clamps to hold the specimen is essential to ensure the validity and reliability of the experimental results.

[0003] Considering the deformation characteristics of tensile-torsional combined loading, the test fixture must meet the following three requirements: First, it must have sufficient clamping force to prevent specimen slippage; second, it must have good centering, as specimen tilting can affect measured parameters such as the elastic modulus; and finally, the clamping process should be simple and convenient for experimental operation. However, existing tensile-torsional combined loading test fixtures are difficult to simultaneously meet these three design requirements. Patent CN210665278U discloses a tensile-torsional combined fixture based on a positive and negative thread structure, which requires machining positive and negative threads at the specimen end and is cumbersome to clamp; Patent CN209215091U discloses a tensile-torsional combined fixture for a tensile testing machine, which can only be used for individual torsion tests and tensile-torsional combined tests on a tensile testing machine, lacking versatility and only applicable to specimens with a circular cross-section; Patent CN217901373U discloses a test fixture for tensile and torsion testing, which is also only applicable to specimens with a circular cross-section. Therefore, there is an urgent need to design a tensile-torsion composite loading test fixture that is simple in structure, easy to clamp, has strong clamping force, good centering, and can adapt to specimens with various cross-sectional shapes. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the prior art by proposing a wedge-shaped clamp for tensile-torsion combined loading tests. This clamp is used for the effective holding of specimens in monotonic tensile, monotonic torsion, and tensile-torsion combined loading tests, providing a powerful experimental tool for studying the elastoplastic deformation and damage fracture mechanisms of materials under complex loading conditions.

[0005] To achieve the above technical content, the present invention is implemented through the following technical solution:

[0006] A wedge clamp for a tensile-torsion combined loading test is characterized by comprising an annular locking cover (1), a wedge clamping block (3), and a circular clamp base plate (4); the wedge clamping block (3) has a groove inside that has the same configuration as the end of the specimen, so that the specimen can be clamped and the end can be fitted and centered along the axis; the annular locking cover (1) has a wedge groove on its inner side, and the wedge clamping block (3) can be embedded into the wedge groove inside the annular locking cover (1) after the specimen is clamped inside; the circular clamp base plate (4) contacts the wedge clamping block (3) through a central disc (7) on the base plate, and the circular clamp base plate (4) and the annular locking cover (1) are locked by four T-screws I (2), thereby applying axial pressure to the wedge clamping block (3) and causing the two inclined surfaces of the wedge groove inside the annular locking cover (1) to face the wedge. The clamping block (3) is subjected to an inward preload to ensure that the sample can be firmly clamped before the start of monotonic tension, monotonic torsion and tension-torsion composite loading. The circular clamp base plate (4) is provided with eight threaded holes, four of which are connected to the annular locking cover (1) by T-screws I (2) to fix the wedge clamping block (3) and the sample. The remaining four threaded holes are bolted to the tension-torsion composite sensor (6) by T-screws II (5) to realize the real-time transmission of axial tensile load and in-plane torque load. The circular clamp base plate (4) has a raised base plate center disk (7). The base plate center disk (7) contacts the wedge clamping block (3). The four T-screws I (2) connected to the annular locking cover (1) apply axial pressure to the wedge clamping block (3) so that the sample is fixedly clamped under the action of the initial preload.

[0007] The internal wedge groove of the annular locking cover (1) is an isosceles trapezoidal shape; the diameter of the outer end of the annular locking cover (1) is larger than the width of the sample end, and smaller than the front short side dimension of the wedge clamping block (3), ensuring that the sample can pass through the annular locking cover (1) and can also hold the wedge clamping block (3); the annular locking cover (1) is machined with four threaded holes, which can be tightly connected to the circular clamp base plate (4) by bolts, thereby fixing the wedge clamping block (3).

[0008] The wedge-shaped clamping blocks (3) are in the shape of an isosceles trapezoid after they are fitted together; the length of the wedge-shaped clamping blocks (3) is slightly shorter than the depth of the wedge groove on the inner side of the annular locking cover (1), ensuring that there is a certain gap in the axial direction after the wedge-shaped clamping blocks (3) are fitted together with the annular locking cover (1); the wedge-shaped clamping blocks (3) have a groove with the same configuration as the end of the sample, so that the two clamping blocks still retain a certain gap after the sample is clamped; the above two gaps ensure that the wedge-shaped clamping blocks (3) fully clamp the sample under the axial pressure of the circular clamp base plate (4).

[0009] Through the reasonable cooperation of the annular locking cover (1), the wedge clamping block (3) and the circular clamp base plate (4), the sample can be clamped tighter and tighter after monotonic tension, monotonic torsion and combined tension and torsion loading, thereby ensuring the effectiveness of the test.

[0010] The cross-sectional configuration of the sample is circular and square.

[0011] The beneficial effects of this invention are as follows: 1. The wedge structure ensures that the specimen is pre-tightened before monotonic tension, monotonic torsion, and combined tension and torsion loading, and also ensures that the specimen is clamped tighter and tighter after loading, thereby ensuring the validity of the test results; 2. The structure is simple, the clamping is convenient, and the specimen centering effect is good; 3. The clamping blocks can be replaced to adapt to specimens of different sizes, and the invention has strong expandability and versatility. Attached Figure Description

[0012] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate the invention and are used to explain it, but do not constitute an undue limitation of the invention.

[0013] Figure 1 This is an overall diagram showing the connection between the present invention and the tension / torsion sensor.

[0014] Figure 2 This is an assembly diagram of the present invention.

[0015] Figure 3 This is a schematic diagram of the circular clamp base plate structure of the present invention.

[0016] Figure 4 This is a schematic cross-sectional view of the entire invention.

[0017] Figure 5 This is a schematic cross-sectional view of the assembly of the present invention.

[0018] The markings in the diagram are: 1. Annular locking cover; 2. T-screw I; 3. Wedge clamping block; 4. Circular clamp base plate; 5. T-screw II; 6. Tension-torsion composite sensor; 7. Center disc of the base plate. Detailed Implementation

[0019] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0020] The following description, in conjunction with the accompanying drawings, further illustrates the detailed content of the present invention and its specific embodiments.

[0021] See Figures 1 to 5 As shown, a wedge clamp for a tensile-torsion combined loading test according to the present invention includes an annular locking cover (1), a wedge clamping block (3), and a circular clamp base plate (4). The wedge clamping block (3) has a groove inside that has the same configuration as the end of the specimen. After the specimen is clamped, the end can be fitted and centered along the axis, ensuring that the specimen will not slide or shift during tensile loading. The annular locking cover (1) has a wedge groove on its inner side. After the specimen is clamped inside the wedge clamping block (3), it can be embedded into the wedge groove on the inner side of the annular locking cover (1), ensuring that the specimen does not rotate during torsional loading. The circular clamp base plate (4) contacts the wedge clamping block (3) through a central disk (7) on the base plate. The circular clamp base plate (4) and the annular locking cover (1) are locked together by four T-screws I (2), thereby applying axial pressure to the wedge clamping block (3) and causing the annular locking cover to lock together. The two inclined surfaces of the wedge-shaped groove inside the outer cover (1) apply an inward pre-tightening force to the wedge-shaped clamping block (3) to ensure that the sample can be firmly clamped before the start of monotonic tension, monotonic torsion and tension-torsion composite loading. The circular clamp base plate (4) is provided with eight threaded holes, four of which are connected to the annular locking outer cover (1) by T-screws I (2) to fix the wedge-shaped clamping block (3) and the sample. The remaining four threaded holes are bolted to the tension-torsion composite sensor (6) by T-screws II (5) to realize the real-time transmission of axial tensile load and in-plane torque load. The circular clamp base plate (4) has a raised base plate center disk (7). The base plate center disk (7) contacts the wedge-shaped clamping block (3). The four T-screws I (2) connected to the annular locking outer cover (1) apply axial pressure to the wedge-shaped clamping block (3) so that the sample is fixedly clamped under the action of the initial pre-tightening force.

[0022] See Figure 5 As shown, the wedge-shaped groove inside the annular locking cover (1) is an isosceles trapezoidal shape; the diameter of the outer end of the annular locking cover (1) is larger than the width of the sample end, and smaller than the front short side dimension of the wedge clamping block (3), ensuring that the sample can pass through the annular locking cover (1) and can also hold the wedge clamping block (3); the annular locking cover (1) is machined with four threaded holes, which can be tightly connected to the circular clamp base plate (4) by bolts, thereby fixing the wedge clamping block (3).

[0023] See Figure 4 As shown, the wedge-shaped clamping blocks (3) are in the shape of an isosceles trapezoid after being fitted together; the length of the wedge-shaped clamping blocks (3) is slightly shorter than the depth of the wedge groove on the inner side of the annular locking cover (1), ensuring that there is a certain gap in the axial direction after the wedge-shaped clamping blocks (3) are fitted together with the annular locking cover (1); the wedge-shaped clamping blocks (3) have a groove with the same configuration as the end of the sample, so that the two clamping blocks still retain a certain gap after the sample is clamped; the above two gaps ensure that the wedge-shaped clamping blocks (3) fully clamp the sample under the axial pressure of the circular clamp base plate (4).

[0024] Through the reasonable cooperation of the annular locking cover (1), the wedge clamping block (3) and the circular clamp base plate (4), the sample can be clamped tighter and tighter after monotonic tension, monotonic torsion and combined tension and torsion loading, thereby ensuring the effectiveness of the test.

[0025] The cross-sectional configuration of the sample is circular and square.

[0026] In summary, once the fixture and the specimen are fully and completely fixed, tensile-torsional monotonic or combined loading can be applied. Simultaneously, the uniaxial tensile load and in-plane torsion are transmitted to the tensile-torsional composite sensor through the fixture, enabling the measurement of test data. This method has the advantages of low cost, lightweight design, and wedge-shaped self-locking. Different types and sizes of specimens can be tested by changing the specimen clamping block.

[0027] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A wedge-shaped clamp for tensile-torsion combined loading tests, characterized in that: The device includes an annular locking cover (1), a wedge-shaped clamping block (3), and a circular clamp base plate (4). The wedge-shaped clamping block (3) has a groove inside that has the same configuration as the end of the sample, so that the sample can be clamped and the end can be fitted and centered along the axis. The annular locking cover (1) has a wedge-shaped groove on its inner side. After the sample is clamped inside the wedge-shaped clamping block (3), it can be embedded into the wedge-shaped groove inside the annular locking cover (1). The circular clamp base plate (4) contacts the wedge-shaped clamping block (3) through a central disc (7) on the base plate. The circular clamp base plate (4) and the annular locking cover (1) are locked together by four T-screws I (2), thereby applying axial pressure to the wedge-shaped clamping block (3) and causing the two inclined surfaces of the wedge-shaped groove inside the annular locking cover (1) to apply inward preload to the wedge-shaped clamping block (3). Force is applied to ensure that the sample can be firmly clamped before the start of monotonic tension, monotonic torsion and tension-torsion combined loading. The circular clamp base plate (4) is provided with eight threaded holes, four of which are connected to the annular locking cover (1) by T-screws I (2) to fix the wedge clamping block (3) and the sample. The remaining four threaded holes are bolted to the tension-torsion combined sensor (6) by T-screws II (5) to realize the real-time transmission of axial tensile load and in-plane torque load. The circular clamp base plate (4) has a raised base plate center disk (7). The base plate center disk (7) contacts the wedge clamping block (3). The four T-screws I (2) connected to the annular locking cover (1) apply axial pressure to the wedge clamping block (3) so that the sample is fixedly clamped under the action of the initial preload.

2. The wedge-shaped clamp for a tensile-torsion combined loading test according to claim 1, characterized in that: The internal wedge groove of the annular locking cover (1) is an isosceles trapezoidal shape; the diameter of the outer end of the annular locking cover (1) is larger than the width of the sample end, and smaller than the front short side dimension of the wedge clamping block (3), ensuring that the sample can pass through the annular locking cover (1) and can also hold the wedge clamping block (3); the annular locking cover (1) is machined with four threaded holes, which can be tightly connected to the circular clamp base plate (4) by bolts, thereby fixing the wedge clamping block (3).

3. The wedge-shaped clamp for a tensile-torsion combined loading test according to claim 1, characterized in that: The wedge-shaped clamping blocks (3) are in the shape of an isosceles trapezoid after they are fitted together; the length of the wedge-shaped clamping blocks (3) is slightly shorter than the depth of the wedge groove on the inner side of the annular locking cover (1), ensuring that there is a certain gap in the axial direction after the wedge-shaped clamping blocks (3) are fitted together with the annular locking cover (1); the wedge-shaped clamping blocks (3) have a groove with the same configuration as the end of the sample, so that the two clamping blocks still retain a certain gap after the sample is clamped; the above two gaps ensure that the wedge-shaped clamping blocks (3) fully clamp the sample under the axial pressure of the circular clamp base plate (4).

4. The wedge-shaped clamp for a tensile-torsion combined loading test according to claim 1, characterized in that: Through the reasonable cooperation of the annular locking cover (1), the wedge clamping block (3) and the circular clamp base plate (4), the sample can be clamped tighter and tighter after monotonic tension, monotonic torsion and combined tension and torsion loading, thereby ensuring the effectiveness of the test.

5. A wedge-shaped clamp for a tensile-torsion combined loading test according to claim 1, characterized in that: The cross-sectional configuration of the sample is circular and square.

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