High-temperature tension-torsion composite fatigue test system

Abstract

The invention provides a high-temperature tension-torsion composite fatigue test system, and relates to the technical field of material fatigue tests. The high-temperature tension-torsion composite fatigue test system comprises a test piece and two matched clamps, wherein one matching clamp can be matched with one end of the test piece, and the other matching clamp can be matched with the other end of the test piece; any one of the matched clamps comprises a first clamp and a second clamp; one end of the first clamp can be sleeved in the second clamp, and the end part of the test piece can extend into the second clamp and is in threaded connection with the first clamp; the side walls of the two ends of the test piece are respectively provided with at least one first matching surface, and the inner wall of the second clamp is provided with a second matching surface which can be matched with the first matching surface; and when the end part of the test piece is in threaded connection with the first clamp, the first matching surface is matched with the second matching surface. The mounting firmness between the test piece and the clamp can be improved.

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 actual engineering, most parts are subjected to multi-axial loads, and tension-torsion composite fatigue is one of its typical multi-axial failure modes. Carrying out tension-torsion composite fatigue tests under appropriate working conditions for the materials used in engineering components is the basis for analyzing their fatigue behavior, revealing the failure mechanism, and establishing a life prediction model.

[0003] In the related art, a high temperature tension-torsion composite fatigue test is generally carried out by matching a sample with a fixture to reduce the size of the sample. However, the installation firmness between the sample and the fixture is poor, which is not convenient for carrying out a high temperature tension-torsion composite fatigue test.

[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 the 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 implementation of the high-temperature tension-torsion composite fatigue test.

[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 matching surface is respectively provided on the side walls at both ends of the test piece, and a second matching surface capable of matching with the first matching 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 mating 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 sleeved 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 present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings herein are incorporated into the specification 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 accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0025] Figure 1 FIG. 1 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 It 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. 4 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 FIG. 1 is a schematic diagram of the structure of a test piece in one embodiment of the present disclosure.

[0029] Figure 5 FIG. 1 is a schematic structural diagram of a 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 FIG. 4 is a schematic diagram of the structure of a 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 a variety of forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted. In addition, the drawings are only 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 relative relationship of one component of the illustration to another component, these terms are used in this specification only for convenience, such as according to the orientation of the examples described in the drawings. It is understood that if the device of the illustration is turned upside down, the component described as "upper" will become the component "lower". When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through another 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 an open-ended inclusive meaning and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second" and "third" etc. are used merely as labels and are not intended to limit the quantity of their objects.

[0038] In the related technology, aerospace components such as turbine blades and turbine shafts work in high temperature environments. The high-temperature alloy materials used are expensive, and the sample length is 190mm, resulting in high test costs. In order to reduce the cost of fatigue testing, it is necessary to reduce the size of the sample and use a fixture that matches the sample to fix the sample on a tension-torsion composite testing machine for high-temperature tension-torsion composite fatigue testing.

[0039] In the related art, a tension-torsion fixture and a sample are matched by a pin to match the sleeve with the sample, which is convenient for the installation and removal of the sample. However, in order to facilitate the installation of the tension-torsion composite test fixture, there is a large gap between the sleeve, the sample and the pin when matching, which will lead to poor installation firmness between the sample and the fixture, and there is a risk of the pin sliding or falling off during the test, which is not convenient for the high-temperature tension-torsion composite fatigue test.

[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 matching fixture 2 and a specimen 1 is shown, and the connection relationship between another matching fixture 2 and the specimen 1 is similar). Among them, one matching fixture 2 can be matched with one end of the specimen 1, and the other matching fixture 2 can be matched with the other end of the specimen 1. Any matching fixture 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 end of the specimen 1 can extend into the second fixture 22 and be threadedly connected with the first fixture 21; at least one first matching surface 11 is respectively provided on the side walls at both ends of the specimen 1, and the inner wall of the second fixture 22 is provided with a second matching surface 221 that can match with the first matching surface 11. When the end of the specimen 1 is threadedly connected with the first fixture 21, the first matching surface 11 matches with the second matching surface 221.

[0041] In this way, the specimen 1 is matched with the first fixture 21 by threaded connection, and the specimen 1 is matched with the second fixture 22 by the first matching surface 11 and the second matching surface 221. Compared with the installation method in the related art, the gap between the specimen 1 and the matching fixture 2 is reduced, on the one hand, the installation firmness between the specimen 1 and the matching fixture 2 is improved, so as to facilitate the high-temperature tension-torsion composite fatigue test of the specimen 1; on the other hand, it can solve the problem of the mismatch of the "load-displacement curve" of the specimen 1, and improve the linearity and continuity of the "load-displacement curve" of the specimen 1. At the same time, due to the improvement of the installation firmness between the specimen 1 and the matching fixture 2, the size of the specimen 1 can be further reduced to reduce the test cost of the specimen 1.

[0042] It should be noted that the first mating surface 11 and the second mating surface 221 can be a plane or a curved surface, as long as the circumferential limit of the specimen 1 is 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, in which the specimen 1 will undergo a corresponding displacement change after a 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, and a jump or lag phenomenon occurs, 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 reduce the cost of the specimen 1 .

[0044] In one embodiment of the present disclosure, see Figure 1 and Figure 4, a connection portion 12 is provided at the end of the specimen 1, a threaded hole 211 is provided at one end of the first fixture 21 for threadedly mating with the connection portion 12, and an external thread that is mating with the threaded hole 211 is provided on the peripheral wall of the connection portion 12. The specimen 1 and the first fixture 21 are threadedly connected through the connection portion 12 and the threaded hole 211. On the one hand, the tightness of the connection between the specimen 1 and the first fixture 21 is improved, so that the specimen 1 is more reliable during the test process; on the other hand, it is also convenient for the installation and disassembly of the specimen 1 and the first fixture 21. In some other embodiments of the present disclosure, a connection portion 12 is provided at one end of the first fixture 21, a threaded hole 211 is provided at the end of the specimen 1 for threadedly mating with the connection portion 12, and an external thread that is mating with the threaded hole 211 is provided on the peripheral wall of the connection portion 12. 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, the four second mating surfaces 221 are evenly distributed along the circumference of the second fixture 22, and two adjacent first mating surfaces 11 are connected, and two 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 that the connection part 12 is subjected to excessive stress in the tension-torsion composite experiment, which is conducive 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 fixture 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 prevents the specimen 1 from moving during the test, but also improves the centering of the specimen 1 and the matching fixture 2 when they are installed, which is convenient for installation and is conducive to strict control of the test conditions and improves the accuracy of the 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 4, the 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 changes from small to large 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 changes from small to large 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 7.1mm~7.3mm. The minimum width of the second mating surface 221 along the radial direction of the second fixture 22 is 7.1mm~7.3mm; and the minimum width of the first mating surface 11 along the radial direction of the specimen 1 is substantially 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 7.1mm, 7.2mm, 7.3mm, etc., and the minimum width of the second mating surface 221 along the radial direction of the second fixture 22 is 7.1mm, 7.2mm, 7.3mm, etc. Thus, 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, the specimen 1 can be prevented from sliding into the second fixture 22, thereby further improving the firmness of the installation. In addition, the material of the specimen 1 is reduced, thereby reducing the test cost.

[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 mating between the specimen 1 and the second fixture 22. Thus, by setting the first mating surface 11 and the second mating surface 221 as inclined surfaces, during the installation process of the test piece 1 and the mating fixture 2, through the cooperation between the wedge-shaped surfaces, on the one hand, the test pieces 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, the test piece 1 can be prevented from sliding into the second fixture 22, thereby further improving the installation firmness. In addition, the material of the test piece 1 is reduced, thereby reducing the test cost.

[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 smaller than the radius of the first fixture 21. In other words, the second mating surface 221 has a high point and a low point, the distance from the high point to the axis of the second fixture 22 is 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 smaller than the radius of the first fixture 21. In this way, when the first fixture 21, the second fixture 22 and the test piece 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 sliding out of the second fixture 22, so as to improve the installation firmness of the test piece 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 fixture 21 away from the threaded hole 211, and the retaining ring 212 is integrally connected to the first fixture 21. The outer diameter of the retaining ring 212 is not less than the outer diameter of the second fixture 22. When the first mating surface 11 is mated with the second mating surface 221, the end of the second fixture 22 away from the second mating surface 221 abuts against the side wall of the retaining ring 212. In this way, when the first fixture 21, the second fixture 22 and the specimen 1 are installed, the retaining ring 212 can abut against the end of the second fixture 22 away from the second mating surface 221 to prevent the end of the first fixture 21 extending into the second fixture 22 from sliding out of the second fixture 22, so as to improve the installation firmness of the specimen 1 and the mating fixture 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, a human hand or a wrench can rotate the operating block 213 to make the first clamp 21 and the specimen 1 threadedly connected. Since the operating block 213 is arranged in a cubic shape, it can prevent the human 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 to further save the material of the test piece 1 and reduce the test 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 , a connection relationship between a matching fixture 2 and a specimen 1 is shown, and a connection relationship between another matching fixture 2 and the specimen 1 is similar). Among them, one matching fixture 2 can be matched with one end of the specimen 1, and the other matching fixture 2 can be matched with the other end of the specimen 1.

[0055] Among them, see Figure 4 , the cross section of the midpoint of the axis of the specimen 1 is symmetrically arranged, and the cross section of the midpoint of the axis of the specimen 1 is perpendicular to the axis of the specimen 1. The specimen 1 is divided into a coaxial cylindrical portion, an arc portion, a matching portion and a connecting portion 12 from the cross section close to the midpoint of the axis of the specimen 1 to the cross section far from the midpoint of the axis of the specimen 1. Among them, the cylindrical portion is arranged in a cylindrical shape, and the distance between the cylindrical portion is 3mm and the length is 6mm. One end of the arc portion is connected to the cylindrical portion, and the other end is connected to the matching portion. The diameter of the arc portion increases from small to large from close to the cylindrical portion to far from the cylindrical portion; the fillet radius of the arc portion is 16mm. Four first matching surfaces 11 are evenly arranged on the peripheral wall of the matching portion, and the first matching surface 11 is a wedge-shaped surface, and two adjacent first matching surfaces 11 are connected. The width of the first matching surface 11 along the radial direction of the specimen 1 changes from small to large from far away from the center of the specimen 1 to close to the center of the specimen 1; and the minimum width of the first matching surface 11 along the radial direction of the 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 an external thread, the major diameter of the external thread is 5 mm, the minor diameter is 4.2 mm, the pitch is 0.8 mm, and the length of the external thread is 9 mm. The length of the specimen 1 is 52 mm.

[0056] See also Figure 1 Any of the matching 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. An operating block 213 is coaxially and integrally connected to the side of the retaining ring 212 away from the threaded hole 211, 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 of which are 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 at one end of the second fixture 22 is provided with a second mating surface 221 that can be matched with the first mating surface 11, the number of the second mating surfaces 221 is four, the four second mating surfaces 221 are evenly distributed along the circumference of the second fixture 22, and the four second mating surfaces 221 are wedge-shaped surfaces. The width of the second mating surface 221 along the radial direction of the second fixture 22 changes from small to large from the end surface far away from the second fixture 22 to the end surface 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 7.2mm, and the maximum width of the second mating surface 221 along the radial direction of the second fixture 22 is 9.32mm. And the minimum width of the first mating surface 11 along the radial direction of the specimen 1 is roughly 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. 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 matched with the threaded hole 211 , the first matching surface 11 is tightly fitted with the second matching surface 221 , and one first matching surface 11 is tightly fitted with one second matching surface 221 .

[0060] In this way, the specimen 1 is matched with the first fixture 21 by threaded connection, and the specimen 1 is matched with the second fixture 22 by the first matching surface 11 and the second matching surface 221. Compared with the installation method in the related art, the gap between the specimen 1 and the matching fixture 2 is reduced, on the one hand, the installation firmness between the specimen 1 and the matching fixture 2 is improved, so as to facilitate the high-temperature tension-torsion composite fatigue test of the specimen 1; on the other hand, it can solve the problem of the mismatch of the "load-displacement curve" of the specimen 1, and improve the linearity and continuity of the "load-displacement curve" of the specimen 1. At the same time, due to the improvement of the installation firmness between the specimen 1 and the matching fixture 2, the size of the specimen 1 can be further reduced to reduce the test 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 connecting portion 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 connecting portion 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 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 a second fixture 22 of a matching fixture 2, so that the first matching surface 11 and the second matching surface 221 are closely fitted;

[0065] Next, insert the end of the first fixture 21 with the threaded hole 211 into the second fixture 22 so that the connection portion 12 is aligned with the threaded hole 211, and rotate the operating block 213 with one hand to rotate the first fixture 21, and hold the second fixture 22 and the specimen 1 with one hand until the connection portion 12 and the threaded hole 211 are tightly matched;

[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 with 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 one 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 modification, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary techniques in the art that are not disclosed in the present disclosure. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present disclosure are 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 matching surface is respectively provided on the side walls at both ends of the test piece, and a second matching surface capable of matching with the first matching 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.

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

4. The high temperature tension-torsion composite fatigue testing system according to claim 3 is characterized in that: The first mating surface and the second mating surface are both wedge-shaped surfaces.

5. The high temperature tension-torsion composite fatigue testing system according to claim 4 is characterized in that: The angle between the first mating surface and the axis of the test piece is 5° to 15°; The included angle between the second mating surface and the axis of the second fixture is 5° to 15°.

6. The high temperature tension-torsion composite fatigue testing system according to claim 5, characterized in that: The minimum distance between the second matching surface and the axis of the second fixture is smaller than the radius of the first fixture.

7. The high temperature tension-torsion composite fatigue testing system according to claim 2, characterized in that: A retaining ring is sleeved 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.

8. The high temperature tension-torsion composite fatigue testing system according to claim 7, 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.

9. The high temperature tension-torsion composite fatigue testing system according to claim 8, characterized in that: The depth of the threaded hole is greater than the length of the connecting portion.

10. The high temperature tension-torsion composite fatigue testing system according to any one of claims 1 to 9, characterized in that: The length of the test piece is 51 mm to 53 mm.

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