A high-temperature tension-torsion composite fatigue testing system

Abstract

The present disclosure provides a high-temperature tension-torsion composite fatigue test system, which relates to the technical field of material fatigue testing. The high-temperature tension-torsion composite fatigue test system includes a specimen and two mating fixtures; wherein, one mating fixture can be mated with one end of the specimen, and the other mating fixture can be mated with the other end of the specimen; any of the mating fixtures includes a first fixture and a second fixture; one end of the first fixture can be sleeved in the second fixture, and the end of the specimen can be inserted into the second fixture and threadedly connected to the first fixture; at least one first mating surface is provided on each of the two end side walls of the specimen, and the inner wall of the second fixture is provided with a second mating surface that can be mated with the first mating surface; when the end of the specimen is threadedly connected to the first fixture, the first mating surface is mated with the second mating surface. The present disclosure can improve the installation firmness between the specimen and the fixture.

Description

Technical Field

[0001] The present disclosure relates to the technical field of material fatigue testing, and in particular to a high-temperature tension-torsion composite fatigue testing system. Background Art

[0002] Fatigue fracture is a typical failure mode of mechanical components. In practical engineering, most components are subjected to multiaxial loading, and combined tension-torsion fatigue is a typical multiaxial failure mode. Conducting combined tension-torsion fatigue testing under appropriate operating conditions for the materials used in engineering components is fundamental to analyzing their fatigue behavior, revealing failure mechanisms, and establishing life prediction models.

[0003] In the related art, high-temperature tension-torsion combined fatigue testing is generally performed by combining a specimen with a fixture to reduce the specimen size. However, the mounting security between the specimen and the fixture is poor, making it inconvenient to perform high-temperature tension-torsion combined fatigue testing.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the Invention

[0005] The purpose of the present disclosure is to overcome the deficiencies of the above-mentioned prior art and provide a high-temperature tension-torsion composite fatigue test system to improve the installation firmness between the specimen and the fixture, thereby facilitating the conduct of high-temperature tension-torsion composite fatigue tests.

[0006] The present disclosure provides a high-temperature tension-torsion composite fatigue test system, comprising a test piece and two matching fixtures;

[0007] Wherein, one of the mating fixtures can be mated with one end of the specimen, and the other mating fixture can be mated with the other end of the specimen;

[0008] Any of the mating fixtures includes a first fixture and a second fixture;

[0009] One end of the first fixture can be sleeved in the second fixture, and the end of the test piece can extend into the second fixture and be threadedly connected to the first fixture;

[0010] At least one first mating surface is respectively provided on the side walls at both ends of the test piece, and a second mating surface capable of mating with the first mating surface is provided on the inner wall of the second fixture;

[0011] When the end of the test piece is threadedly connected to the first fixture, the first mating surface is mated with the second mating surface.

[0012] In one embodiment of the present disclosure, a connecting portion is provided at the end of the specimen, and a threaded hole for threadedly engaging with the connecting portion is provided at one end of the first fixture.

[0013] In one embodiment of the present disclosure, the number of the first mating surfaces and the number of the second mating surfaces are both four, the four first mating surfaces are evenly distributed along the circumference of the specimen, and the four second mating surfaces are evenly distributed along the circumference of the second fixture.

[0014] In one embodiment of the present disclosure, both the first mating surface and the second mating surface are wedge-shaped surfaces.

[0015] In one embodiment of the present disclosure, the angle between the first mating surface and the axis of the test piece is 5° to 15°;

[0016] The included angle between the second mating surface and the axis of the second fixture is 5° to 15°.

[0017] In one embodiment of the present disclosure, a minimum distance between the second mating surface and the axis of the second fixture is smaller than a radius of the first fixture.

[0018] In one embodiment of the present disclosure, a retaining ring is provided on one end of the first clamp away from the threaded hole;

[0019] When the first mating surface is mated with the second mating surface, one end of the second clamp away from the second mating surface abuts against the side wall of the retaining ring.

[0020] In one embodiment of the present disclosure, an operating block is provided at one end of the first clamp away from the threaded hole; the operating block is located on a side of the retaining ring away from the threaded hole.

[0021] In one embodiment of the present disclosure, the depth of the threaded hole is greater than the length of the connecting portion.

[0022] In one embodiment of the present disclosure, the length of the test piece is 51 mm to 53 mm.

[0023] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0025] Figure 1 FIG1 is an overall structural diagram of a high-temperature tension-torsion composite fatigue testing system in one embodiment of the present disclosure.

[0026] Figure 2 FIG1 is a partial structural diagram of a high-temperature tension-torsion composite fatigue testing system in one embodiment of the present disclosure.

[0027] Figure 3 FIG. 1 is a cross-sectional view of a high-temperature tension-torsion composite fatigue testing system in one embodiment of the present disclosure.

[0028] Figure 4 Schematic diagram of the structure of a test piece in one embodiment of the present disclosure.

[0029] Figure 5 Schematic diagram of the structure of the first clamp in one embodiment of the present disclosure.

[0030] Figure 6 FIG. 4 is a cross-sectional view of a first clamp in one embodiment of the present disclosure.

[0031] Figure 7 Schematic diagram of the structure of the second clamp in one embodiment of the present disclosure.

[0032] Figure 8 FIG. 4 is a cross-sectional view of a second clamp in one embodiment of the present disclosure.

[0033] Description of reference numerals:

[0034] 1. Test piece; 11. First mating surface; 12. Connecting portion; 2. Mating fixture; 21. First fixture; 211. Threaded hole; 212. Retaining ring; 213. Operating block; 22. Second fixture; 221. Second mating surface. DETAILED DESCRIPTION

[0035] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. Like reference numerals in the figures represent identical or similar structures, and thus their detailed descriptions will be omitted. Furthermore, the figures are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale.

[0036] Although relative terms such as "upper" and "lower" are used in this specification to describe the relationship of one illustrated component to another, these terms are used herein for convenience only, such as in accordance with the orientation of the illustrations in the accompanying drawings. It will be understood that if the illustrated device were flipped upside down, the component described as "upper" would become the component "lower." When a structure is referred to as "on" another structure, this may mean that the structure is integrally formed with the other structure, that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure via the other structure.

[0037] The terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of one or more elements / components / etc.; the terms "including" and "having" are used to express open-ended inclusion and mean that additional elements / components / etc. may be present in addition to the listed elements / components / etc.; the terms "first", "second" and "third" etc. are used only as labels and are not intended to limit the quantity of their objects.

[0038] In related technologies, aerospace components such as turbine blades and turbine shafts operate in high-temperature environments. The high-temperature alloy materials used are expensive, and the specimen length is 190 mm, resulting in high testing costs. To reduce fatigue testing costs, it is necessary to reduce the specimen size and use a fixture that matches the specimen to secure it to a tension-torsion composite testing machine for high-temperature tension-torsion composite fatigue testing.

[0039] One related art method for aligning a tension-torsion fixture with a specimen uses a pin to mate a sleeve with the specimen, facilitating specimen installation and removal. However, to facilitate installation, this tension-torsion composite test fixture has a large gap between the sleeve, specimen, and pin. This results in poor mounting security between the specimen and the fixture, creating a risk of pin slippage or fallout during testing, making it difficult to conduct high-temperature tension-torsion composite fatigue testing.

[0040] In order to solve the above problems, the present disclosure provides a high temperature tension-torsion composite fatigue test system. Figure 1-Figure 3 The high temperature tension-torsion composite fatigue test system includes a specimen 1 and two matching fixtures 2 ( Figure 1-Figure 3, the connection relationship between a mating fixture 2 and a specimen 1 is shown, and the connection relationship between another mating fixture 2 and the specimen 1 is similar). Among them, one mating fixture 2 can be mated with one end of the specimen 1, and the other mating fixture 2 can be mated with the other end of the specimen 1. Any of the mating fixtures 2 includes a first fixture 21 and a second fixture 22; one end of the first fixture 21 can be sleeved into the second fixture 22, and the end of the specimen 1 can extend into the second fixture 22 and be threadedly connected to the first fixture 21; at least one first mating surface 11 is provided on each of the side walls at both ends of the specimen 1, and the inner wall of the second fixture 22 is provided with a second mating surface 221 that can be mated with the first mating surface 11. When the end of the specimen 1 is threadedly connected to the first fixture 21, the first mating surface 11 is mated with the second mating surface 221.

[0041] In this way, by threading the specimen 1 and the first fixture 21 together, and mating the specimen 1 and the second fixture 22 together via the first mating surface 11 and the second mating surface 221, the gap between the specimen 1 and the mating fixture 2 is reduced compared to the installation methods in the related art. This not only improves the installation security between the specimen 1 and the mating fixture 2, but also facilitates high-temperature tension-torsion composite fatigue testing of the specimen 1. It also solves the problem of misalignment in the "load-displacement curve" of the specimen 1, improving the linearity and continuity of the "load-displacement curve" of the specimen 1. Furthermore, due to the improved installation security between the specimen 1 and the mating fixture 2, the size of the specimen 1 can be further reduced, thereby reducing the testing cost of the specimen 1.

[0042] It should be noted that the first mating surface 11 and the second mating surface 221 can be either a plane or a curved surface, as long as the circumferential limitation of the specimen 1 can be achieved through the first mating surface 11 and the second mating surface 221. The "load-displacement curve" refers to the curve reflecting the relationship between the load and displacement deformation of the specimen 1 and the corresponding displacement change after the load is applied to the specimen 1. In the related art, due to the large gap between the specimen 1 and the mating fixture 2, as the load applied to the specimen 1 increases, the displacement of the specimen 1 changes disproportionately, resulting in a jump or lag phenomenon, thereby affecting the linearity and continuity of the "load-displacement curve".

[0043] In one embodiment of the present disclosure, the specimen 1 is arranged in a symmetrical “dog-bone” shape to reduce the material of the specimen 1 and lower the cost of the specimen 1 .

[0044] In one embodiment of the present disclosure, see Figure 1 and Figure 4, the end of the specimen 1 is provided with a connecting portion 12, and one end of the first clamp 21 is provided with a threaded hole 211 for threadedly mating with the connecting portion 12, and the peripheral wall of the connecting portion 12 is provided with an external thread that matches the threaded hole 211. The specimen 1 and the first clamp 21 are threadedly connected through the connecting portion 12 and the threaded hole 211. On the one hand, the tightness of the connection between the specimen 1 and the first clamp 21 is improved, making the specimen 1 more reliable during the test; on the other hand, it is also convenient for the installation and disassembly of the specimen 1 and the first clamp 21. In other embodiments of the present disclosure, one end of the first clamp 21 is provided with a connecting portion 12, and the end of the specimen 1 is provided with a threaded hole 211 for threadedly mating with the connecting portion 12, and the peripheral wall of the connecting portion 12 is provided with an external thread that matches the threaded hole 211. In this way, by providing the threaded hole 211 on the specimen 1, the material of the specimen 1 can be further reduced, thereby reducing the test cost of the specimen 1.

[0045] In one embodiment of the present disclosure, see Figure 1 、 Figure 2 、 Figure 7 The number of the first mating surfaces 11 and the number of the second mating surfaces 221 are both four. The four first mating surfaces 11 are evenly distributed along the circumference of the specimen 1, and the four second mating surfaces 221 are evenly distributed along the circumference of the second fixture 22. Adjacent first mating surfaces 11 are connected, and adjacent second mating surfaces 221 are connected. In this way, through the close contact between the four first mating surfaces 11 and the four second mating surfaces 221, on the one hand, the tension-torsion composite load can be more evenly loaded on the multiple first mating surfaces 11, avoiding the situation where the connection portion 12 is subjected to excessive stress during the tension-torsion composite experiment, which is beneficial to improving the reliability of the specimen 1 in the test and the accuracy of the results, and also extending the actual service life of the specimen 1. On the other hand, the first fixture 21 is threadedly connected to the specimen 1 through the connection portion 12, and the second mating surfaces 221 are tightly fitted with the first mating surfaces 11. This double locking mechanism not only prevents the specimen 1 from moving during the test, but also improves the centering of the specimen 1 and the mating fixture 2 during installation, facilitating installation while facilitating strict control of test conditions and improving the accuracy of test results. In some other embodiments of the present disclosure, the number of the first mating surfaces 11 and the number of the second mating surfaces 221 may both be three, five, six, etc.

[0046] In one embodiment of the present disclosure, see Figure 1 、 Figure 2 and Figure 4The first mating surface 11 and the second mating surface 221 are both wedge-shaped surfaces. The width of the first mating surface 11 along the radial direction of the specimen 1 increases from the end of the specimen 1 to the center of the specimen 1. The width of the second mating surface 221 along the radial direction of the second fixture 22 increases from the end surface away from the second fixture 22 to the end surface close to the second fixture 22. The minimum width of the first mating surface 11 along the radial direction of the specimen 1 is 7.1 mm to 7.3 mm. The minimum width of the second mating surface 221 along the radial direction of the second fixture 22 is 7.1 mm to 7.3 mm. The minimum width of the first mating surface 11 along the radial direction of the specimen 1 is approximately the same as the minimum width of the second mating surface 221 along the radial direction of the second fixture 22. For example, the minimum width of the first mating surface 11 along the radial direction of the specimen 1 is 7.1 mm, 7.2 mm, 7.3 mm, etc., and the minimum width of the second mating surface 221 along the radial direction of the second fixture 22 is 7.1 mm, 7.2 mm, 7.3 mm, etc. Thus, by configuring the first mating surface 11 and the second mating surface 221 as wedge-shaped surfaces, the wedge-shaped surfaces cooperate during the installation of the specimen 1 and the mating fixture 2. This not only allows specimens 1 of varying sizes to be installed in the mating fixture 2, improving the versatility of the mating fixture 2, but also prevents the specimen 1 from sliding into the second fixture 22, further enhancing mounting security. Furthermore, this reduces the material requirements of the specimen 1 and lowers testing costs.

[0047] It should be noted that, in the embodiments of the present disclosure, “substantially the same” means that there is a fitting tolerance between the hole and the shaft, and therefore the values ​​are not absolutely the same.

[0048] In one embodiment of the present disclosure, see Figure 3 and Figure 8 , the angle between the first mating surface 11 and the axis of the specimen 1 is 5° to 15°. For example, the angle between the first mating surface 11 and the axis of the specimen 1 is 5°, 10°, 15°, etc. The angle between the second mating surface 221 and the axis of the second fixture 22 is 5° to 15°. For example, the angle between the second mating surface 221 and the axis of the second fixture 22 is 5°, 10°, 15°, and the angle between the first mating surface 11 and the axis of the specimen 1 is the same as the angle between the second mating surface 221 and the axis of the second fixture 22, so as to facilitate the fit between the specimen 1 and the second fixture 22. By designing the first mating surface 11 and the second mating surface 221 as inclined surfaces, the wedge-shaped surfaces cooperate during the installation of the specimen 1 and the mating fixture 2. This allows specimens 1 of varying sizes to be installed in the mating fixture 2, improving the versatility of the mating fixture 2. Furthermore, it prevents the specimen 1 from sliding into the second fixture 22, further enhancing mounting security. Furthermore, this reduces the material requirements of the specimen 1 and lowers testing costs.

[0049] In one embodiment of the present disclosure, see Figure 3 The minimum distance between the second mating surface 221 and the axis of the second fixture 22 is less than the radius of the first fixture 21. In other words, the second mating surface 221 has a high point and a low point, with the distance from the high point to the axis of the second fixture 22 greater than the distance from the low point to the axis of the second fixture 22, and the distance from the low point to the axis of the second fixture 22 is less than the radius of the first fixture 21. This ensures that when the first and second fixtures 21, 22, and specimen 1 are installed, the end of the first fixture 21 extending into the second fixture 22 can abut against the second fixture 22, preventing the end of the first fixture 21 extending into the second fixture 22 from slipping out of the second fixture 22, thereby improving the secure installation between the specimen 1 and the mating fixture 2.

[0050] In one embodiment of the present disclosure, see Figure 1 、 Figure 5 and Figure 6 , a retaining ring 212 is sleeved on one end of the first clamp 21 away from the threaded hole 211, and the retaining ring 212 is integrally connected to the first clamp 21. The outer diameter of the retaining ring 212 is not less than the outer diameter of the second clamp 22. When the first mating surface 11 is mated with the second mating surface 221, the end of the second clamp 22 away from the second mating surface 221 abuts against the side wall of the retaining ring 212. In this way, when the first clamp 21, the second clamp 22 and the specimen 1 are installed, the retaining ring 212 can abut against the end of the second clamp 22 away from the second mating surface 221, preventing the end of the first clamp 21 extending into the second clamp 22 from sliding out of the second clamp 22, thereby improving the installation firmness of the specimen 1 and the mating clamp 2.

[0051] In one embodiment of the present disclosure, see Figure 1 、 Figure 5 and Figure 6 , an operating block 213 is provided at one end of the first clamp 21 away from the threaded hole 211. The operating block 213 is located on the side of the retaining ring 212 away from the threaded hole 211. And the operating block 213 is arranged in a cubic shape. In this way, when loading and unloading the specimen 1 and the matching clamp 2, the operating block 213 can be rotated by hand or a wrench to thread the first clamp 21 and the specimen 1. Since the operating block 213 is arranged in a cubic shape, it can prevent the hand or the wrench from slipping, thereby improving the convenience and efficiency of loading and unloading.

[0052] In one embodiment of the present disclosure, the depth of the threaded hole 211 is greater than the length of the connecting portion 12. In this way, connecting portions 12 of different lengths can be matched with the threaded hole 211, further improving the versatility of the test piece 1 and the matching fixture 2.

[0053] In one embodiment of the present disclosure, the length of the test piece 1 is 51 mm to 53 mm. For example, the length of the test piece 1 can be 51 mm, 52 mm, 53 mm, etc. In this way, the length of the test piece 1 is reduced, thereby further saving material of the test piece 1 and reducing the testing cost of the test piece 1.

[0054] In one embodiment of the present disclosure, see Figure 1 The high temperature tension-torsion composite fatigue test system includes a specimen 1 and two matching fixtures 2 ( Figure 1 , the connection relationship between one mating fixture 2 and the specimen 1 is shown, and the connection relationship between the other mating fixture 2 and the specimen 1 is similar). Among them, one mating fixture 2 can be mated with one end of the specimen 1, and the other mating fixture 2 can be mated with the other end of the specimen 1.

[0055] Among them, see Figure 4 Specimen 1 is symmetrically arranged along the cross section at the midpoint of its own axis, and the cross section at the midpoint of specimen 1's axis is perpendicular to the axis of specimen 1. Specimen 1 is divided into a coaxial cylindrical portion, an arcuate portion, a mating portion, and a connecting portion 12, from the cross section closest to the midpoint of its own axis to the cross section away from the midpoint of its own axis. The cylindrical portion is cylindrical, with a 3mm gap and a length of 6mm. The arcuate portion is connected to the cylindrical portion at one end and to the mating portion at the other end. The diameter of the arcuate portion increases from closest to the cylindrical portion to further away from the cylindrical portion; the fillet radius of the arcuate portion is 16mm. Four first mating surfaces 11 are evenly arranged on the circumferential wall of the mating portion. These first mating surfaces 11 are wedge-shaped, connecting two adjacent first mating surfaces 11. The width of the first mating surfaces 11 along the radial direction of specimen 1 increases from smallest to largest, from further away from the center of specimen 1 to closer to the center of specimen 1. The minimum width of the first mating surfaces 11 along the radial direction of specimen 1 is 7.2mm. The angle between the first mating surface 11 and the axis of the specimen 1 is 10°. The connecting portion 12 is connected to the end of the mating portion away from the center of the specimen 1. The peripheral wall of the connecting portion 12 is provided with external threads. The threads have a major diameter of 5 mm, a minor diameter of 4.2 mm, a pitch of 0.8 mm, and a length of 9 mm. The specimen 1 is 52 mm long.

[0056] See also Figure 1 Any of the mating fixtures 2 includes a first fixture 21 and a second fixture 22. One end of the first fixture 21 can be sleeved in the second fixture 22, and the connecting portion 12 can extend into the second fixture 22 and be threadedly connected to the first fixture 21.

[0057] See also Figure 5 and Figure 6, one end of the first clamp 21 is coaxially provided with a threaded hole 211 for threaded cooperation with the connecting part 12, and the other end is coaxially sleeved with a retaining ring 212, and the retaining ring 212 is integrally connected to the first clamp 21. The retaining ring 212 is coaxially and integrally connected to the side of the threaded hole 211 away from the retaining ring 212, and the operating block 213 is arranged in a cubic shape. Among them, the length of the first clamp 21 is 101mm, and the outer diameter of the first clamp 21 is 11mm. The length and width of the operating block 213 are the same, both 10.8mm, and the height of the operating block 213 is 6mm. The outer diameter of the retaining ring 212 is 15.6mm, and the length of the retaining ring 212 is 6mm. The major diameter of the threaded hole 211 is 5mm, the pitch is 0.8mm, and the depth is 10mm.

[0058] See also Figure 7 and Figure 8 The inner circumferential wall of one end of the second fixture 22 is provided with a second mating surface 221 capable of mating with the first mating surface 11. There are four second mating surfaces 221, which are evenly distributed along the circumference of the second fixture 22 and are all wedge-shaped. The width of the second mating surface 221 along the radial direction of the second fixture 22 increases from small to large from the end face away from the second fixture 22 to the end face close to the second fixture 22. The minimum width of the second mating surface 221 along the radial direction of the second fixture 22 is 7.2 mm, and the maximum width of the second mating surface 221 along the radial direction of the second fixture 22 is 9.32 mm. The minimum width of the first mating surface 11 along the radial direction of the specimen 1 is approximately the same as the minimum width of the second mating surface 221 along the radial direction of the second fixture 22, so that the first mating surface 11 and the second mating surface 221 can fit tightly together. The angle between the second mating surface 221 and the axis of the second fixture 22 is 10°. The outer diameter of the second clamp 22 is 15.6 mm, the inner diameter of the second clamp 22 is 11 mm, and the length of the second clamp 22 is 95 mm.

[0059] See also Figure 3 When the connecting portion 12 is mated with the threaded hole 211 , the first mating surface 11 is tightly fitted with the second mating surface 221 , and one first mating surface 11 is tightly fitted with one second mating surface 221 .

[0060] In this way, by threading the specimen 1 and the first fixture 21 together, and mating the specimen 1 and the second fixture 22 together via the first mating surface 11 and the second mating surface 221, the gap between the specimen 1 and the mating fixture 2 is reduced compared to the installation methods in the related art. This not only improves the installation security between the specimen 1 and the mating fixture 2, but also facilitates high-temperature tension-torsion composite fatigue testing of the specimen 1. It also solves the problem of misalignment in the "load-displacement curve" of the specimen 1, improving the linearity and continuity of the "load-displacement curve" of the specimen 1. Furthermore, due to the improved installation security between the specimen 1 and the mating fixture 2, the size of the specimen 1 can be further reduced, thereby reducing the testing cost of the specimen 1.

[0061] Through the close contact between the four first mating surfaces 11 and the four second mating surfaces 221, on the one hand, the tension-torsion composite load can be more evenly loaded on the multiple first mating surfaces 11, avoiding the situation where the connection part 12 is subjected to excessive stress in the tension-torsion composite experiment, which is beneficial to improving the reliability of the specimen 1 in the test and the accuracy of the results, and also prolonging the actual service life of the specimen 1; on the other hand, the first clamp 21 is threadedly connected to the specimen 1 through the connection part 12, and the second mating surface 221 is tightly fitted with the first mating surface 11. Such a double locking mechanism not only avoids the movement of the specimen 1 during the test, but also improves the concentricity of the specimen 1 and the mating clamp 2 during installation, which is convenient for installation and is conducive to strict control of the test conditions and improves the accuracy of the test results.

[0062] By setting the first mating surface 11 and the second mating surface 221 as wedge-shaped surfaces, during the installation process of the specimen 1 and the mating fixture 2, through the cooperation between the wedge-shaped surfaces, on the one hand, specimens 1 of different sizes can be installed with the mating fixture 2, thereby improving the versatility of the mating fixture 2; on the other hand, it can also prevent the specimen 1 from sliding into the inside of the second fixture 22, thereby further improving the installation firmness.

[0063] The installation process of the test piece 1 and the matching fixture 2 of the present disclosure is described in detail below.

[0064] First, one end of the test piece 1 is inserted into the second fixture 22 of a matching fixture 2 so that the first matching surface 11 and the second matching surface 221 are tightly fitted;

[0065] Next, insert the end of the first clamp 21 with the threaded hole 211 into the second clamp 22 so that the connecting portion 12 is aligned with the threaded hole 211. Rotate the operating block 213 with one hand to rotate the first clamp 21, and hold the second clamp 22 tightly at the joint with the specimen 1 with the other hand until the connecting portion 12 is tightly fitted with the threaded hole 211.

[0066] Afterwards, use an inner square wrench to clamp the operating block 213 to tighten the connecting portion 12 and the threaded hole 211;

[0067] Then, use the above steps to install the other end of the test piece 1 and another matching fixture 2;

[0068] Finally, the assembled specimen 1 and the matching fixture 2 are installed on the tension-torsion composite testing machine, so that the hydraulic chuck of the tension-torsion composite testing machine clamps the second fixture 22 away from the end of the specimen 1. Based on this, the specimen 1 can be subjected to a high-temperature tension-torsion composite fatigue test.

[0069] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the appended claims.

Claims

1. A high temperature tension-torsion composite fatigue test system, characterized in that: Includes test piece and two matching fixtures; Wherein, one of the mating fixtures can be mated with one end of the specimen, and the other mating fixture can be mated with the other end of the specimen; Any of the mating fixtures includes a first fixture and a second fixture; One end of the first fixture can be sleeved in the second fixture, and the end of the test piece can extend into the second fixture and be threadedly connected to the first fixture; At least one first mating surface is respectively provided on the side walls at both ends of the test piece, and a second mating surface capable of mating with the first mating surface is provided on the inner wall of the second fixture; When the end of the test piece is threadedly connected to the first fixture, the first mating surface is mated with the second mating surface; The number of the first mating surfaces and the number of the second mating surfaces are both four, the four first mating surfaces are evenly distributed along the circumference of the specimen, and the four second mating surfaces are evenly distributed along the circumference of the second fixture; The first mating surface and the second mating surface are both wedge-shaped surfaces; The angle between the first mating surface and the axis of the test piece is 5° to 15°; The angle between the second mating surface and the axis of the second fixture is 5° to 15°; The minimum distance between the second mating surface and the axis of the second fixture is smaller than the radius of the first fixture.

2. The high-temperature tension-torsion composite fatigue testing system according to claim 1, characterized in that: A connecting portion is provided at the end of the test piece, and a threaded hole for threadedly engaging with the connecting portion is provided at one end of the first fixture.

3. The high temperature tension-torsion composite fatigue testing system according to claim 2, characterized in that: A retaining ring is provided on one end of the first clamp away from the threaded hole; When the first mating surface is mated with the second mating surface, one end of the second clamp away from the second mating surface abuts against the side wall of the retaining ring.

4. The high-temperature tension-torsion composite fatigue testing system according to claim 3, characterized in that: An operating block is provided at one end of the first clamp away from the threaded hole; the operating block is located at a side of the retaining ring away from the threaded hole.

5. The high temperature tension-torsion composite fatigue testing system according to claim 4, characterized in that: The depth of the threaded hole is greater than the length of the connecting portion.

6. The high temperature tension-torsion composite fatigue testing system according to any one of claims 1 to 5, characterized in that: The length of the test piece is 51 mm to 53 mm.

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