A tensile impact fatigue experimental device based on a high-frequency impact fatigue experimental machine

Abstract

This invention provides a tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine, belonging to the technical field of mechanical property testing equipment. It includes: a support base, a force measuring system, a compression-tension conversion device, a secondary impact protection system, and an impact hammer. The support base has a longitudinally formed groove on its support arm. The compression-tension conversion device includes a crossbeam, a lower clamping plate, and a slide rail, with the slide rail slidingly engaging the groove to allow the compression-tension conversion device to be slidably mounted on the support arm. The force measuring system includes a fixing component fixed to the top of the support arm and securing the top of the test sample; the bottom of the test sample is fixed to the lower clamping plate. The secondary impact protection system includes an elastic support member and a support plate. The impact hammer moves downward at a set speed, compressing the elastic support member and striking the crossbeam to apply a tensile load to the test sample. This invention can accurately measure the impact load on the sample after compression-tension conversion, avoiding interference from the dynamic response of the conversion device itself.

Description

Technical Field

[0001] This invention relates to the field of mechanical property testing equipment, specifically to a tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine. Background Technology

[0002] The high-frequency impact fatigue testing machine utilizes a rotating cam to drive the impact hammer to repeatedly lift and drop, thereby achieving repeated impacts on the specimen. It can impact up to four times per second, making its testing efficiency far higher than that of the standard drop hammer impact testing machine. Due to the significantly increased impact frequency, existing actuated cylinder-type anti-secondary impact solutions are unsuitable. To achieve the conversion from impact compression to impact tension, existing specimens are often fixed to the clamps at both ends with double nuts, making precise control of the specimen locking length difficult. Furthermore, the locking process inevitably applies torque to the middle section of the specimen, severely affecting the experimental results. Existing standard drop hammer impact testing machines use a force sensor on the hammer head to measure the impact force; however, in impact tension tests, after the impact force is converted by the clamps, the actual impact force experienced by the specimen does not match the force measured at the hammer head, necessitating an improved force measurement scheme.

[0003] Therefore, existing impact compression to impact tension conversion devices suffer from problems such as inaccurate measurement of the impact force borne by the specimen, lack of protection against secondary impacts under high-frequency impacts, and easy twisting during specimen clamping. In addition, existing tensile impact fatigue testing schemes based on drop hammer / pendulum testing machines are inefficient, with each impact typically taking 30-90 seconds, resulting in high economic and time costs when conducting impact fatigue tests. Summary of the Invention

[0004] In view of this, the present application provides a tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine to solve the problems of inaccurate measurement of the impact load borne by the specimen in high-frequency impact fatigue testing, lack of protection against secondary impact under high-frequency impact, and easy torsion during specimen clamping.

[0005] This application provides the following technical solution: a tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine, comprising: a support base, a force measuring system, a compression-tension conversion device, a secondary impact protection system, and an impact hammer;

[0006] The support base includes a base plate and two support arms that are fixed to the base plate. The outer side of the support arms has a longitudinal groove. The compression-tension conversion device is slidably mounted on the support base; the compression-tension conversion device includes a crossbeam and a lower clamping plate, and two slide rails fixed between the crossbeam and the lower clamping plate. The crossbeam, the slide rails and the lower clamping plate are fixedly arranged to form a rectangular frame structure. The slide rails are slidably engaged with the slide grooves so that the compression-tension conversion device is slidably mounted on the support arm of the support base. The force measuring system includes a fixing component for fixing the test sample. The fixing component is fixedly disposed at the top end of the support arm to clamp and fix the top end of the test sample. The fixing component is provided with a force sensor for measuring the tensile load borne by the test sample. The bottom end of the test sample is fixed to the lower clamping plate of the compression-tension conversion device. The secondary impact protection system includes an elastic support and a support plate. The bottom end of the elastic support is fixed to the fixing assembly, and the support plate is fixed to the top end of the elastic support. A through hole is provided on the support plate, and the impact hammer passes through the through hole so that the impact hammer moves downward at a set speed under the drive of the hammer body of the testing machine, compressing the elastic support and impacting the crossbeam of the compression-tension conversion device. This causes the compression-tension conversion device to move downward on the support arm, converting the compression impact from above into a tensile load on the test sample.

[0007] According to one embodiment of the present invention, the fixing assembly includes: an upper clamping plate and a pre-tensioning plate, the upper clamping plate being fixedly disposed at the top end of the support arm, the pre-tensioning plate being located above the upper clamping plate and used to clamp the top end of the test sample; a force sensor being disposed between the upper clamping plate and the pre-tensioning plate and used to measure the tensile load borne by the test sample; and a nut being used to fasten the pre-tensioning plate, the force sensor, the upper clamping plate, and the top end of the test sample to the top of the pre-tensioning plate.

[0008] According to one embodiment of the present invention, the number of force sensors is two, and the two force sensors are symmetrically arranged between the upper clamping plate and the pretensioning plate.

[0009] According to one embodiment of the present invention, the elastic support includes a support rod, a spring, a rubber pad, a threaded sleeve, and a locking nut; the bottom end of the support rod is fixedly mounted on the upper clamping plate, the spring is sleeved on the support rod, and the upper end of the spring abuts against the support plate; the rubber pad is attached to the upper surface of the support plate for contacting the impact hammer; the threaded sleeve and the locking nut are mounted on the top end of the support rod above the rubber pad to fix and adjust the pre-compression of the spring.

[0010] According to one embodiment of the present invention, the impact hammer includes an inner hammer head and an outer hammer head arranged coaxially, the diameter of the outer hammer head being larger than the diameter of the inner hammer head; wherein, the diameter of the through hole on the support plate is adapted to the diameter of the inner hammer head, so that the inner hammer head passes through the through hole; the outer hammer head is provided with a thread for connecting with the hammer body of the experimental machine.

[0011] According to one embodiment of the present invention, the test sample includes a straight section in the middle, anti-rotation sections located at both ends of the straight section, and a threaded section connected to the anti-rotation section. The straight section and the anti-rotation section are smoothly connected by an arc-shaped transition section. The lower clamping plate and the pre-tightening plate are respectively provided with anti-rotation holes that match the shape of the anti-rotation section, so as to prevent the test sample from twisting during clamping and loading.

[0012] According to one embodiment of the present invention, the cross-section of the anti-rotation segment is a rounded rectangle, and the anti-rotation hole is a rounded rectangular hole.

[0013] According to one embodiment of the present invention, the slide groove on the support arm includes an upper half and a lower half with different structures. The upper half is a U-shaped groove, and a U-shaped notch is formed on the edge of the upper clamping plate. Both the U-shaped notch and the U-shaped groove are adapted to the shape of the slide rail to limit the movement of the slide rail. The lower half is a square groove that passes through the support arm. The square groove and the two ends of the lower clamping plate form a clearance fit so that the two ends of the lower clamping plate pass through the square groove and are fixedly assembled with the slide rail by bolts.

[0014] Compared with the prior art, the beneficial effects that at least one technical solution adopted in the embodiments of this specification can achieve include at least: 1. The embodiments of the present invention achieve protection against secondary impacts during high-frequency repeated impacts. The secondary impact protection system has good durability and long service life, and is suitable for high-life impact fatigue test.

[0015] 2. The sample and clamping design of the present invention can achieve stable and reliable clamping during the compression-tension conversion process, while avoiding the torsion problem during the sample clamping process.

[0016] 3. The embodiments of the present invention can accurately measure the impact load on the sample after compression-tension conversion, avoiding interference from the dynamic response of the conversion device itself. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the tensile impact fatigue testing device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the impact hammer structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the anti-secondary impact system according to an embodiment of the present invention; Figure 4 This is an exploded view of the secondary impact protection system according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the compression-stretching conversion device according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the force measuring system structure according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the pretensioning plate structure according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the upper clamping plate structure according to an embodiment of the present invention; Figure 9 This is a front view of the test sample according to an embodiment of the present invention; Figure 10 This is a perspective view of the test sample according to an embodiment of the present invention; Figure 11 This is a front view of the support arm according to an embodiment of the present invention; Figure 12 This is a perspective view of the support arm according to an embodiment of the present invention; Among them, 1-impact hammer; 2-anti-secondary impact system; 3-compression-tension conversion device; 4-force measuring system; 5-test sample; 6-support base; 11-inner hammer head; 12-outer hammer head; 21-support rod; 22-spring; 23-support plate; 24-rubber pad; 25-threaded sleeve; 26-locking nut; 31-crossbeam; 32-slide rail; 33-lower clamping plate; 41-upper clamping plate; 42-pretensioning plate; 43-force sensor; 51-nut. Detailed Implementation

[0019] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0020] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] like Figure 1 As shown, this embodiment of the invention provides a tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine, including: a support base 6, a force measuring system 4, a compression-tension conversion device 3, a secondary impact protection system 2, an impact hammer 1, and a test sample 5.

[0022] The support base 6 includes a base plate and two support arms fixed to the base plate. Longitudinal grooves are formed on the outer sides of the support arms. The compression-tension conversion device 3 is slidably mounted on the support base 6. The compression-tension conversion device 3 includes a crossbeam 31 and a lower clamping plate 33, and two slide rails 32 fixed between the crossbeam 31 and the lower clamping plate 33. The crossbeam 31, the slide rails 32, and the lower clamping plate 33 form a rectangular frame structure. The slide rails 32 slide in conjunction with the grooves, allowing the compression-tension conversion device 3 to be slidably mounted on the support arms of the support base 6. The force measuring system 4 includes a fixing component for fixing the test sample 5. The fixing component is fixedly mounted on the top end of the support arm to clamp and fix the top end of the test sample 5. A force sensor is installed to measure the tensile load borne by the test sample 5. The bottom end of the test sample 5 is fixed on the lower clamping plate 33 of the compression-tension conversion device 3. The anti-secondary impact system 2 includes an elastic support and a support plate 23. The bottom end of the elastic support is fixed on the fixing assembly, and the support plate 23 is fixed on the top end of the elastic support. A through hole is opened on the support plate 23, and the impact hammer 1 passes through the through hole so that the impact hammer 1 moves downward at a set speed under the drive of the hammer body of the testing machine, compressing the elastic support and impacting the crossbeam 31 of the compression-tension conversion device 3. This causes the compression-tension conversion device 3 to move downward on the support arm, so as to convert the compression impact from above into a tensile load on the test sample 5.

[0023] In some embodiments of the present invention, such as Figure 2As shown, the impact hammer 1 includes an inner hammer head 11 and an outer hammer head 12 coaxially nested, with the diameter of the outer hammer head 12 being larger than the diameter of the inner hammer head 11. The diameter of the through hole on the support plate 23 is adapted to the diameter of the inner hammer head 11, allowing the inner hammer head 11 to pass through the through hole. The outer hammer head 12 is provided with threads for connection to the hammer body of the experimental machine, and is installed on the hammer body of the experimental machine through these threads. During the experiment, the hammer body of the experimental machine drives the inner hammer head 11 and the outer hammer head 12 to move downwards together at a set speed.

[0024] In some embodiments of the present invention, such as Figures 6-8 As shown, the fixing assembly includes: an upper clamping plate 41 and a pre-tightening plate 42. The upper clamping plate 41 is fixedly disposed at the top end of the support arm, and the pre-tightening plate 42 is located above the upper clamping plate 41 for clamping the top end of the test sample 5. A force sensor 43 is disposed between the upper clamping plate 41 and the pre-tightening plate 42 for measuring the tensile load borne by the test sample 5. A nut 51 is used to fasten the pre-tightening plate 42, the force sensor 43, the upper clamping plate 41, and the top end of the test sample 5 to the top of the pre-tightening plate 42. Preferably, in this embodiment, there are two force sensors 43, which are symmetrically disposed between the upper clamping plate 41 and the pre-tightening plate 42.

[0025] In specific implementation, the force measuring system 4 consists of an upper clamping plate 41, a pre-tightening plate 42, two dynamic force sensors, an amplifier (not shown in the figure), and a high-speed data acquisition unit (not shown in the figure). The bottom surface of the pre-tightening plate 42 includes a circular through hole and a rounded rectangular hole for clamping the sample and preventing the sample from twisting. The bottom surface of the pre-tightening plate 42 and the top surface of the upper clamping plate 41 both include two small circular bosses for pressing the two force-bearing end faces of the dynamic force sensors. The center of the two small bosses on the bottom surface of the pre-tightening plate 42 is a circular countersunk hole, and the center of the two small bosses on the top surface of the upper clamping plate 41 is a circular blind hole. The nut 51 passes through the center holes of the upper and lower small bosses to fasten the pre-tightening plate 42, the force sensor 43, and the upper clamping plate 41 together.

[0026] In some embodiments of the present invention, the elastic support includes a support rod 21, a spring 22, a rubber pad 24, a threaded sleeve 25, and a locking nut 26; the bottom end of the support rod 21 is fixedly mounted on the upper clamping plate 41, the spring 22 is sleeved on the support rod 21, and the upper end of the spring 22 abuts against the support plate 23; the rubber pad 24 is attached to the upper surface of the support plate 23 for contacting the impact hammer 1; the threaded sleeve 25 and the locking nut 26 are mounted on the top end of the support rod 21 above the rubber pad 24 to fix and adjust the pre-compression of the spring 22.

[0027] In specific implementation, such as Figures 3-4As shown, the secondary impact protection system consists of a support rod 21, a spring 22, a support plate 23, a rubber pad 24, a threaded sleeve 25, and a locking nut 26. The support plate 23 and the rubber pad 24 are glued together, with a central through hole. The hole allows the inner hammer 11 to pass through, but the outer hammer 12 cannot. During the experiment, the hammer body of the testing machine drives the inner hammer 11 and the outer hammer 12 to move downwards together at a set speed. The inner hammer 11 passes through the central hole on the support plate 23 and the rubber pad 24, while the outer hammer 12 directly contacts the rubber pad 24, thus pressing down on the rubber pad 24. This causes the support plate 23 and the rubber pad 24 to move downwards together, and presses down on the spring 22 until the inner hammer 11 strikes the compression-tension conversion device 3, applying an impact tensile load to the test sample 5. After the impact, the impact hammer 1 rebounds, the spring 22 returns to its original position, and the support plate 23 and the rubber pad 24 move upwards along with the impact hammer 1. However, due to gravity, the impact hammer 1 will reciprocate up and down multiple times. Without the secondary impact prevention system 2, this subsequent reciprocating motion will strike the compression-tension conversion device 3 and load the sample, thus generating a secondary impact phenomenon. The load amplitude of the secondary impact does not meet the experimental requirements and interferes with the experimental results. However, in this device, according to different initial impact velocities, by adjusting the stiffness of the spring 22 and the initial position of the threaded sleeve 25, the energy of the reciprocating motion of the impact hammer 1 can be transferred to the spring 22, the support plate 23, and the rubber pad 24, absorbing and dissipating this energy, thereby preventing the sample from being subjected to secondary impact.

[0028] like Figure 5 As shown, the compression-tension conversion device 3 consists of a crossbeam 31, a slide rail 32, and a lower clamping plate 33. The lower clamping plate 33 includes a circular through hole and a rounded rectangular hole for clamping the test sample 5.

[0029] In some embodiments of the present invention, the test sample 5 includes a straight section in the middle, anti-rotation sections located at both ends of the straight section, and a threaded section connected to the anti-rotation section. The straight section and the anti-rotation section are smoothly connected by an arc-shaped transition section. The lower clamping plate 33 and the pre-tightening plate 42 are respectively provided with anti-rotation holes that match the shape of the anti-rotation section, so as to prevent the test sample 5 from twisting during clamping and loading.

[0030] In specific implementation, the test sample 5 adopts a special shape design, such as... Figures 9-10As shown. Each end of the sample contains a threaded section that can mate with the nut 51. Between the arc-shaped transition section and the threaded section of the sample is a rounded rectangular anti-rotation section. The straight section in the middle of the sample is connected to the anti-rotation section through the arc-shaped transition sections in four directions on the sides. During the experiment, the threaded section of the test sample 5 passes through the circular hole in the center of the lower clamping plate 33, the upper clamping plate 41, and the pre-tightening plate 42. At the same time, the anti-rotation section mates with the rounded rectangular holes on the surface of the circular holes of the lower clamping plate 33 and the pre-tightening plate 42, locking the test sample 5. Then, the nut 51 is used to tighten the test sample 5 to the lower clamping plate 33 and the pre-tightening plate 42, realizing the anti-torsion locking of the sample. During the impact, the crossbeam 31 is hit by the inner hammer 11, and the lower clamping plate 33 is pressed down by the slide rail 32, thereby generating an impact tensile load on the test sample 5. During this process, the impact load is transmitted to the two dynamic force sensors 43 on the left and right through the pre-tightening plate 42, which is converted into an electrical signal. After being amplified (not shown in the figure), it is collected by the high-speed data acquisition device (not shown in the figure).

[0031] In some embodiments of the present invention, the slide groove on the support arm includes an upper half and a lower half with different structures. The upper half is a U-shaped groove, and a U-shaped notch is opened on the edge of the upper clamping plate 41. Both the U-shaped notch and the U-shaped groove are adapted to the shape of the slide rail 32 to limit the position of the slide rail 32. The lower half is a square groove that passes through the support arm. The square groove forms a clearance fit with the two ends of the lower clamping plate 33 so that the two ends of the lower clamping plate 33 pass through the square groove and are fixedly assembled with the slide rail 32 by bolts.

[0032] In practice, the support base 6 adopts a special shape design, such as Figures 11-12 As shown, the middle position of the side support arm contains a special slot, with the slots of the two support arms facing outwards during installation. The upper part of the slot is a U-shaped slot, the same shape as the slot of the upper clamping plate 41, and complementary to the shape of the slide rail 32, thus limiting the slide rail 32 so that it can only slide up and down along the slot; the lower part is a square through slot, the width of which forms a clearance fit with the left and right ends of the lower clamping plate 33, allowing the two ends of the lower clamping plate 33 to pass through the square slot and be assembled with the slide rail 32 by bolts (at the same time, the crossbeam 31 is also assembled with the slide rail 32 by bolts). After assembly, the crossbeam 31, the slide rail 32, and the lower clamping plate 33 can move up and down together along the slot of the support arm, while the junction of the U-shaped slot and the square slot forms a limiting step, which can limit the overall movement endpoint of the crossbeam 31, the slide rail 32, and the lower clamping plate 33.

[0033] The experimental apparatus of this invention exhibits excellent resistance to secondary impacts: by designing a nested impact hammer and spring-support plate energy absorption system, the problem of secondary impacts under high-frequency repeated impacts is effectively solved. The system has good durability and is suitable for high-cycle impact fatigue experiments. Furthermore, this invention fundamentally avoids torsion of the specimen during locking and loading by using a non-circular anti-rotation section on the specimen in conjunction with a rounded rectangular hole on the fixture, ensuring pure axial load transfer and improving experimental accuracy. The scheme of directly integrating a dynamic force sensor into the tensile load transmission path, and eliminating the influence of off-center loading through the symmetrical arrangement of dual sensors, enables direct and accurate measurement of the actual impact tensile load borne by the specimen.

[0034] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine, characterized in that, include: Support base, force measuring system, compression-tension conversion device, secondary impact protection system, and impact hammer; The support base includes a base plate and two support arms that are fixed to the base plate. The outer side of the support arms has a longitudinal groove. The compression-tension conversion device is slidably mounted on the support base; the compression-tension conversion device includes a crossbeam and a lower clamping plate, and two slide rails fixed between the crossbeam and the lower clamping plate. The crossbeam, the slide rails and the lower clamping plate are fixedly arranged to form a rectangular frame structure. The slide rails are slidably engaged with the slide grooves so that the compression-tension conversion device is slidably mounted on the support arm of the support base. The force measuring system includes a fixing component for fixing the test sample. The fixing component is fixedly disposed at the top end of the support arm to clamp and fix the top end of the test sample. The fixing component is provided with a force sensor for measuring the tensile load borne by the test sample. The bottom end of the test sample is fixed to the lower clamping plate of the compression-tension conversion device. The secondary impact protection system includes an elastic support and a support plate. The bottom end of the elastic support is fixed to the fixing assembly, and the support plate is fixed to the top end of the elastic support. A through hole is provided on the support plate, and the impact hammer passes through the through hole so that the impact hammer moves downward at a set speed under the drive of the hammer body of the testing machine, compressing the elastic support and impacting the crossbeam of the compression-tension conversion device. This causes the compression-tension conversion device to move downward on the support arm, converting the compression impact from above into a tensile load on the test sample.

2. The tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine according to claim 1, characterized in that, The fixing assembly includes: an upper clamping plate and a pre-tensioning plate. The upper clamping plate is fixedly disposed at the top end of the support arm, and the pre-tensioning plate is located above the upper clamping plate for clamping the top end of the test sample. The force sensor is disposed between the upper clamping plate and the pre-tensioning plate for measuring the tensile load borne by the test sample. The pre-tensioning plate, the force sensor, the upper clamping plate, and the top end of the test sample are fastened together by a nut above the pre-tensioning plate.

3. The tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine according to claim 2, characterized in that, The force sensor is two in number, and the two force sensors are symmetrically arranged between the upper clamping plate and the pre-tightening plate.

4. The tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine according to claim 2, characterized in that, The elastic support includes a support rod, a spring, a rubber pad, a threaded sleeve, and a locking nut; the bottom end of the support rod is fixedly mounted on the upper clamping plate, the spring is sleeved on the support rod, and the upper end of the spring abuts against the support plate; the rubber pad is attached to the upper surface of the support plate for contact with the impact hammer; the threaded sleeve and locking nut are mounted on the top end of the support rod above the rubber pad to fix and adjust the pre-compression of the spring.

5. The tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine according to claim 1, characterized in that, The impact hammer includes an inner hammer head and an outer hammer head arranged coaxially, the diameter of the outer hammer head being larger than the diameter of the inner hammer head; wherein, the diameter of the through hole on the support plate is adapted to the diameter of the inner hammer head, so that the inner hammer head passes through the through hole; the outer hammer head is provided with a thread for connecting with the hammer body of the experimental machine.

6. The tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine according to claim 2, characterized in that, The test sample includes a straight section in the middle, anti-rotation sections at both ends of the straight section, and a threaded section connected to the anti-rotation section. The straight section and the anti-rotation section are smoothly connected by an arc-shaped transition section. The lower clamping plate and the pre-tightening plate are respectively provided with anti-rotation holes that match the shape of the anti-rotation section, so as to prevent the test sample from twisting during clamping and loading.

7. The tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine according to claim 6, characterized in that, The cross-section of the anti-rotation section is a rounded rectangle, and the anti-rotation hole is a rounded rectangular hole.

8. The tensile impact fatigue testing device based on a high-frequency impact fatigue testing machine according to claim 2, characterized in that, The slide groove on the support arm includes an upper half and a lower half with different structures. The upper half is a U-shaped groove, and a U-shaped notch is opened on the edge of the upper clamping plate. Both the U-shaped notch and the U-shaped groove are adapted to the shape of the slide rail to limit the movement of the slide rail. The lower half is a square groove that passes through the support arm. The square groove and the two ends of the lower clamping plate form a clearance fit so that the two ends of the lower clamping plate pass through the square groove and are fixedly assembled with the slide rail by bolts.

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