CN220154108U - Fatigue testing machine and clamp thereof - Google Patents

Abstract

A fatigue testing machine and a clamp thereof can be used for tensile fatigue test of a coating test piece to evaluate tensile fatigue performance of the coating. The fatigue testing machine is used for tensile fatigue test of a coating test piece, the coating test piece comprises a first carrier, a second carrier and a coating to be detected, the coating to be detected is fixed on the first carrier and the second carrier, and the coating to be detected extends from the first carrier to the second carrier; the fixture comprises: a support base; the fixing assembly is fixedly connected with the supporting seat and is used for fixing the first carrier to the supporting seat; and the moving assembly is movably connected with the supporting seat and is used for movably connecting the second carrier to the supporting seat so that the second carrier can reciprocate relative to the first carrier, and a gap between the first carrier and the second carrier is circularly expanded and contracted so as to drive the part of the coating to be detected, which is positioned at the gap, to circularly stretch and contract.

Description

Fatigue testing machine and clamp thereof

Technical Field

The present disclosure relates to, but not limited to, paint performance testing techniques, and more particularly to a fatigue testing machine and a fixture thereof.

Background

The performance detection of the paint can provide the basis for manufacturing, using and detecting for manufacturers, users and detecting mechanisms of the paint, and quality accidents such as cracking, damage, corrosion of a material matrix and the like of the paint after long-term use are avoided. Currently, there is no device for evaluating the tensile fatigue property of a coating, and a common tensile fatigue testing machine cannot be used for evaluating the tensile fatigue property of the coating.

Disclosure of Invention

The embodiment of the utility model provides a fatigue testing machine and a clamp thereof, which can be used for tensile fatigue test of a coating test piece to evaluate tensile fatigue performance of the coating.

To this end, an embodiment of the present utility model provides a fixture for a fatigue testing machine for a tensile fatigue test of a paint test piece, the paint test piece including a first carrier, a second carrier, and a coating to be detected fixed to the first carrier and the second carrier, the coating to be detected extending from the first carrier to the second carrier; the clamp comprises: a support base; the fixing assembly is fixedly connected with the supporting seat and is used for fixing the first carrier to the supporting seat; and the moving assembly is movably connected with the supporting seat and is arranged for movably connecting the second carrier with the supporting seat, so that the second carrier can reciprocate relative to the first carrier, and a gap between the first carrier and the second carrier is circularly expanded and contracted to drive the part of the coating to be detected, which is positioned at the gap, to circularly stretch and contract.

In an exemplary embodiment, the moving assembly includes a first support plate and a first connection plate, the first support plate being defined at the support base, the first connection plate being arranged to be stacked at a distance from the first support plate such that the second carrier can be sandwiched between the first connection plate and the first support plate; the first connecting plate is fixedly connected with the first supporting plate and matched with the second carrier to clamp the second carrier; the first connecting plate is arranged to drive the second carrier and the first supporting plate to reciprocate relative to the first carrier under the drive of the driving mechanism of the fatigue testing machine.

In an exemplary embodiment, the support base is provided with a guide portion, and the guide portion is in limit fit with the first support plate and is configured to guide the first support plate to linearly reciprocate along a first direction.

In an exemplary embodiment, the guide part includes: a first rail and a second rail extending along the first direction; the first guide rail and the second guide rail are arranged at intervals along a second direction perpendicular to the first direction; the two ends of the first supporting plate in the second direction are respectively in sliding fit with the first guide rail and the second guide rail.

In an exemplary embodiment, the first guide rail is provided with a first chute, one end of the first support plate along the second direction is accommodated in the first chute, and the first chute is further provided with a first avoiding groove which is recessed along the second direction towards a direction away from the first support plate; the second guide rail is provided with a second chute, the other end of the first support plate along the second direction is contained in the second chute, and the second chute is also provided with a second avoiding groove which is recessed along the second direction towards the direction away from the first support plate.

In an exemplary embodiment, the securing assembly includes a second support plate and a second connection plate, the second support plate being defined in the support base, the second connection plate being arranged to be stacked at intervals on the second support plate such that the second carrier can be sandwiched between the second connection plate and the second support plate; the second connecting plate is fixedly connected with the second supporting plate and matched with and clamps the second carrier.

In an exemplary embodiment, the fixing assembly further includes a third connection plate, the second connection plate and the third connection plate are disposed at both sides of the support base, and the second connection plate and the third connection plate are fixedly connected through fasteners and clamp the support base, the second support plate, and the second carrier.

The embodiment of the utility model also provides a fatigue testing machine, which comprises: the clamp of any of the above embodiments; the driving mechanism is connected with the moving assembly of the clamp and is arranged to drive the moving assembly to reciprocate; and the driving mechanism is arranged on the frame, and the supporting seat of the clamp is fixed in the frame.

In an exemplary embodiment, the fatigue testing machine further comprises: the constant temperature box is arranged in the rack, the clamp is positioned in the constant temperature box, and the driving mechanism is positioned outside the constant temperature box; the connecting rod is arranged in the incubator in a penetrating mode, and the driving mechanism is connected with the clamp through the connecting rod.

In an exemplary embodiment, the driving mechanism is configured to drive the moving assembly to reciprocate the second carrier in a vertical direction; or the driving mechanism is arranged to drive the moving assembly to drive the second carrier to reciprocate along the horizontal direction.

The embodiment of the utility model has the following beneficial effects: the tensile fatigue test of the paint test piece can be realized to evaluate the tensile fatigue performance of the paint, and the paint test piece has the advantages of simple structure, convenient operation and suitability for popularization.

Additional features and advantages of the utility model will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model. Other advantages of the utility model may be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The accompanying drawings are included to provide an understanding of the principles of the utility model, and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain, without limitation, the principles of the utility model.

FIG. 1 is a schematic cross-sectional view of a first state of a paint test piece according to an embodiment of the present utility model;

FIG. 2 is a schematic cross-sectional view of the coating test piece of FIG. 1 in a second state;

FIG. 3 is a schematic perspective view of a fatigue testing machine according to an embodiment of the present utility model;

FIG. 4 is a schematic diagram of a front view of a fatigue testing machine according to an embodiment of the present utility model;

FIG. 5 is a schematic view of a part of a clamp according to an embodiment of the present utility model;

FIG. 6 is a schematic diagram of a front view of a fixture according to an embodiment of the present utility model;

FIG. 7 is a schematic cross-sectional view of a clamp according to one embodiment of the present utility model;

FIG. 8 is a schematic cross-sectional view of the clamp of FIG. 7 holding a paint test piece;

FIG. 9 is another cross-sectional schematic view of a clamp provided in accordance with one embodiment of the present utility model;

fig. 10 is a schematic cross-sectional view of the clamp of fig. 9 holding a paint test piece.

The reference numerals are as follows:

100 clamps;

1 a supporting seat, 11 a first guide rail, 111 a first sliding groove, 112 a first avoiding groove, 12 a second guide rail, 121 a second sliding groove and 122 a second avoiding groove;

2 a fixing assembly, 21 a second supporting plate, 22 a second connecting plate and 23 a third connecting plate;

3 moving assembly, 31 first support plate, 311 connecting post, 32 first connecting plate, 33 butterfly nut;

200 driving mechanisms, 202 electric cylinders, 204 reaction frames, 206 displacement sensors, 208 force sensors and 210 connecting rods;

a 300 rack;

400 paint test pieces, 402 first carrier, 404 second carrier, 406 coating to be detected, 408 gap;

500 thermostats, 502 support tables.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, embodiments of the present utility model will be described in detail hereinafter with reference to the accompanying drawings. It should be noted that, without conflict, the embodiments of the present utility model and features of the embodiments may be arbitrarily combined with each other.

As shown in fig. 3 to 10, the embodiment of the present utility model provides a fatigue testing machine and a fixture thereof for tensile fatigue test of a paint test piece 400 to evaluate tensile fatigue performance of paint.

Because the paint cannot be subjected to the tensile fatigue test alone and the tensile fatigue test can be performed only after the film layer is cured on the carrier, when the paint is subjected to the tensile fatigue test, the paint test piece 400 needs to be prepared, the paint test piece 400 is clamped in a clamp, and then the load is loaded through the driving mechanism 200 of the fatigue testing machine to perform the tensile fatigue test.

As shown in fig. 1 and 2, the paint test piece 400 includes a first carrier 402, a second carrier 404, and a coating 406 to be detected fixed to the first carrier 402 and the second carrier 404. In the process of preparing the paint test piece 400, the first carrier 402 and the second carrier 404 may be aligned together, then paint is applied on the first carrier 402 and the second carrier 404, after the paint is cured, the coating 406 to be detected may be formed on the first carrier 402 and the second carrier 404, and the coating 406 to be detected extends from the first carrier 402 to the second carrier 404, as shown in fig. 1. The coating need not be applied to the first carrier 402 and the second carrier 404, but rather, it need only be applied to the first carrier 402 and the second carrier 404 to ensure that the coating is securely held on the first carrier 402 and the second carrier 404, as shown in fig. 1.

During the tensile fatigue test, a gap 408 is formed between the second carrier 404 and the first carrier 402 by pulling the second carrier 404, as shown in fig. 2. By pushing and pulling the second carrier 404 back and forth, the gap 408 between the second carrier 404 and the first carrier 402 can be circularly expanded and contracted, and the coating (or coating film) at the gap 408 is driven to circularly stretch and contract. After a certain number of cycles, the tensile fatigue properties of the coating can be evaluated by observing the presence of defects (such as holes, cracks, breaks, etc.) in the coating (or film) at the gap 408.

As shown in fig. 3 and 4, the fatigue testing machine includes a jig, a driving mechanism 200, and a frame 300.

The paint test piece 400 is held in a clamp. The driving mechanism 200 is mainly used for providing driving force for a tensile fatigue test. As shown in fig. 4, the driving mechanism 200 may be, but is not limited to, an electric cylinder 202, and the electric cylinder 202 may be used in combination with a reaction frame 204. The frame 300 primarily provides a mounting carrier for other structures of the fatigue testing machine. The frame 300 may be frame-like as shown in fig. 3.

As shown in fig. 5 and 6, the fixture includes a support base 1, a fixed component 2 and a movable component 3. The driving mechanism 200 is connected to the moving assembly 3 of the jig, and is configured to drive the moving assembly 3 to reciprocate. The drive mechanism 200 is mounted to the frame 300. The supporting base 1 of the clamp is fixed in the frame 300.

The support base 1 is provided to support the fixed assembly 2, the moving assembly 3, and the paint test piece 400.

The fixing assembly 2 is fixedly connected with the support base 1, and is configured to fix the first carrier 402 to the support base 1, as shown in fig. 10.

The moving assembly 3 is movably connected with the supporting seat 1, and is configured to movably connect the second carrier 404 with the supporting seat 1, as shown in fig. 8, so that the second carrier 404 can reciprocate relative to the first carrier 402, so that a gap 408 between the first carrier 402 and the second carrier 404 is circularly expanded and contracted, and further, a part of the coating 406 to be detected, which is located at the gap 408, is driven to circularly stretch and contract.

Thus, the first carrier 402 is fixed to the support base 1 by the fixing assembly 2, and is kept relatively stationary with respect to the support base 1, and cannot move with respect to the support base 1. The second carrier 404 can reciprocate relative to the support base 1 and the first carrier 402 under the driving of the moving assembly 3, so that the gap 408 between the first carrier 402 and the second carrier 404 is circularly enlarged and reduced. When the gap 408 between the first carrier 402 and the second carrier 404 is enlarged, the portion of the coating 406 to be detected at the gap 408 is stretched; as the gap 408 between the first carrier 402 and the second carrier 404 shrinks, the portion of the coating 406 to be detected at the gap 408 shrinks. After such a cyclic operation is performed several times, the portion of the coating 406 to be detected located at the slit 408 is also cyclically stretched and contracted several times (for example, 2000 times). The tensile fatigue properties of the coating were evaluated by observing the defect condition of the portion of the coating 406 to be detected at the slit 408 after the cyclic stretching shrinkage several times.

Such as: if defects such as holes, cracks, breaks and the like appear at the position of the coating 406 to be detected at the gap 408, the tensile fatigue performance of the coating is poor. If no defect occurs in the portion of the coating 406 to be detected located at the gap 408, the tensile fatigue performance of the coating is better.

Of course, the criteria for evaluating tensile fatigue properties of the coating are not limited to the presence or absence of defects, but may be evaluated by indices such as the number of defects, the size of defects, and the type of defects.

In some embodiments, the first carrier 402 and the second carrier 404 are each a concrete slab.

Of course, the first carrier 402 and the second carrier 404 are not limited to concrete materials, and can be well combined with the paint to ensure that the paint is firmly fixed on the carriers, or the carriers with corresponding materials can be selected according to the specific application scene of the paint.

In some embodiments, as shown in fig. 5 and 7, the moving assembly 3 includes a first support plate 31 and a first connection plate 32. The first supporting plate 31 is limited on the supporting seat 1. The first connection plates 32 are disposed to be stacked at intervals on the first support plate 31 so that the second carrier 404 can be interposed between the first connection plates 32 and the first support plate 31, as shown in fig. 8. The first connecting plate 32 is fixedly connected with the first supporting plate 31 and is matched to clamp the second carrier 404, as shown in fig. 8. The first connecting plate 32 is configured to drive the second carrier 404 and the first supporting plate 31 to reciprocate relative to the first carrier 402 under the driving of the driving mechanism 200 of the fatigue testing machine.

Wherein the first support plate 31 and the first connection plate 32 may be, but are not limited to, metal plates, such as steel plates.

In this way, friction between the second carrier 404 and the supporting seat 1 can be avoided, and the metal plate is smoother, so that friction force is reduced, load of the driving mechanism 200 is reduced, and the first supporting plate 31 and the first connecting plate 32 are fixed conveniently to ensure connection reliability of the moving assembly 3 and the paint test piece 400.

The area of the first support plate 31 may be equal to the area of the second carrier 404, which is beneficial to increasing the static friction between the first support plate 31 and the second carrier 404, and ensuring that the second carrier 404 can move synchronously with the moving assembly 3.

The end of the first connecting plate 32 remote from the first carrier 402 may extend outward to the outside of the support base 1, so as to be connected with the driving mechanism 200.

When the clamp does not clamp the paint test piece 400, the first support plate 31 and the first connection plate 32 may be stacked together to be fixedly connected, so as to prevent the clamp components from being lost, or may be spaced apart.

In some embodiments, the support base 1 is provided with a guide portion, which is in limit fit with the first support plate 31 and is configured to guide the first support plate 31 to linearly reciprocate in the first direction.

In one embodiment, the guide includes: a first rail 11 and a second rail 12 extending in a first direction, as shown in fig. 7 and 9.

The first guide rail 11 and the second guide rail 12 are disposed at intervals along a second direction perpendicular to the first direction. Both ends of the first support plate 31 in the second direction are slidably fitted with the first guide rail 11 and the second guide rail 12, respectively. The first direction may be a length direction of the support base 1, and the second direction may be a width direction of the support base 1.

This advantageously ensures that the second carrier 404 reciprocates in a set linear direction without deflection, so as to avoid as much as possible that the coating 406 to be inspected is subjected to forces in oblique directions, which would affect the evaluation of its tensile fatigue properties.

In some embodiments, as shown in fig. 7, the first rail 11 is provided with a first runner 111. One end of the first support plate 31 along the second direction is accommodated in the first chute 111. The first slide groove 111 is further provided with a first escape groove 112 recessed in the second direction toward a direction away from the first support plate 31.

As shown in fig. 7, the second rail 12 is provided with a second slide groove 121. The other end of the first support plate 31 along the second direction is accommodated in the second chute 121. The second slide groove 121 is further provided with a second escape groove 122 recessed in the second direction toward a direction away from the first support plate 31.

The arrangement of the first avoidance groove 112 and the second avoidance groove 122 can reduce the contact area between the first support plate 31 and the support seat 1, thereby being beneficial to reducing the sliding friction force and reducing the load of the driving mechanism 200.

In some embodiments, as shown in fig. 7, the first support plate 31 is provided with a connection post 311, and the first connection plate 32 is provided with a connection hole. The connecting post 311 is inserted into the connecting hole and is fixedly connected with the first connecting plate 32 by a fastener. The connection post 311 may be, but is not limited to, a threaded post and the fastener may be, but is not limited to, a wing nut 33, as shown in fig. 7.

As shown in fig. 7, the number of the connection posts 311 may be plural, for example, the first support plate 31 may be symmetrically provided with two sets of connection posts 311 along the second direction, and each set of connection posts 311 may also include a plurality of connection posts 311 arranged at intervals along the first direction.

In this way, the first connection plate 32 is firmly connected with the first support plate 31, and the stress balance of the second carrier 404 is facilitated.

The second carrier 404 may be located between two sets of connection posts 311, as shown in fig. 8, so that the connection posts 311 may be prevented from passing through the second carrier 404, which may protect the second carrier 404, and may simplify the assembly process between the paint test piece 400 and the fixture.

In some embodiments, as shown in fig. 5 and 9, the fixing assembly 2 includes a second support plate 21 and a second connection plate 22. The second supporting plate 21 is limited on the supporting seat 1. The second connection plate 22 is disposed to be stacked at a distance from the second support plate 21 so that the second carrier 404 can be interposed between the second connection plate 22 and the second support plate 21, as shown in fig. 10. The second connection plate 22 is fixedly connected with the second support plate 21 and cooperates to clamp the second carrier 404, as shown in fig. 10.

Wherein the second support plate 21 and the second connection plate 22 may be, but are not limited to, metal plates, such as steel plates.

The area of the second support plate 21 may be comparable to the area of the first support plate 402, which is advantageous for increasing the static friction between the second support plate 21 and the first support plate 402, ensuring that the first support plate 402 and the second support plate 21 remain relatively stationary.

The second connection plate 22 may be a plate having a relatively large area, or may include a plurality of plates having a relatively small area, so long as the fixed connection of the second support plate 21 and the second connection plate 22 and the clamping of the first carrier 402 can be achieved.

Both ends of the second support plate 21 in the second direction may also be located in the first and second sliding grooves 111 and 121, respectively. The second support plate 21 may have the same width as the first support plate 31.

The second support plate 21 and the second connection plate 22 may be stacked together to be fixedly connected when the clamp does not clamp the paint test piece 400, so as to prevent the clamp components from being lost, or may be spaced apart.

In some embodiments, an avoidance space for avoiding the coating 406 to be detected is provided between the second connecting plate 22 and the first connecting plate 32 of the moving assembly 3, so as to avoid damaging the coating 406 to be detected in the fixing process of the first connecting plate 32 and the second connecting plate 22, and also ensure that the first connecting plate 32 is tightly attached to the second carrier 404 and the second connecting plate 22 is tightly attached to the first carrier 402.

In some embodiments, as shown in fig. 9 and 10, the securing assembly 2 further includes a third connecting plate 23. The second connecting plate 22 and the third connecting plate 23 are respectively arranged at two sides of the supporting seat 1. The second connecting plate 22 is fixedly connected with the third connecting plate 23 through a fastener, and clamps the supporting seat 1, the second supporting plate 21 and the second carrier 404.

In this way, the supporting seat 1, the first carrier 402 and the second supporting plate 21 are all locked by the second connecting plate 22 and the third connecting plate 23, so that the fixed connection of the supporting seat 1, the first carrier 402 and the fixing assembly 2 is realized, and the three can be kept relatively static.

The connection mode of the second connection plate 22 and the third connection plate 23 can be the same as that of the first connection plate 31 and the first connection plate 32, for example, the connection mode can be fixedly connected with the fastener through the connection column 311, but the connection column 311 can be the outer side of the support seat 1, and the connection process can be more flexible and convenient to operate without the need of being in the support seat 1.

Of course, the structure and the fixing manner of the fixing assembly 2 are not limited thereto, as long as the first carrier 402 can be secured to the support base 1.

In some embodiments, the movement amplitude of the movement assembly 3 is less than or equal to 2mm.

Of course, the movement range of the movement unit 3 is not limited to the above range, and may be adjusted according to the kind of paint and the test requirement.

In some embodiments, the fatigue testing machine further comprises an incubator 500 and a connecting rod 210, as shown in fig. 4.

As shown in fig. 4, the incubator 500 is provided in the rack 300. The clamp is located inside the incubator 500 and the drive mechanism 200 is located outside the incubator 500.

As shown in fig. 4, the connection rod 210 is penetrated through the incubator 500. The drive mechanism 200 is connected to the clamp by a connecting rod 210.

Since the performance of the paint is greatly affected by temperature, the paint test piece 400 can be brought to a set temperature during the tensile fatigue test by the incubator 500, thereby realizing the tensile fatigue test measurement of the paint at the set temperature. By varying the temperature of the incubator 500, tensile fatigue test measurements of the coating at different temperatures can be achieved.

As shown in fig. 4, a supporting table 502 may be disposed in the incubator 500, and an end of the clamp remote from the driving mechanism 200 may be connected to the supporting table 502 through a connection rod 210. Specifically, an end of the support base 1 remote from the driving mechanism 200 may be connected to the support table 502 through the connection rod 210.

In some embodiments, as shown in fig. 4, the fatigue testing machine further comprises: the displacement sensor 206 is arranged to directly or indirectly detect the displacement of the moving assembly 3.

This ensures that the width of the gap 408 between the first carrier 402 and the second carrier 404 is within a set range.

In some embodiments, as shown in fig. 4, the fatigue testing machine further comprises: a force sensor 208 is provided to directly or indirectly detect the pulling force applied by the driving mechanism 200.

In some embodiments, the driving mechanism 200 is configured to drive the moving assembly 3 to reciprocate the second carrier 404 in the vertical direction, as shown in fig. 3 and 4.

Therefore, the space in the vertical direction is convenient to fully utilize, and the occupied area of the fatigue testing machine is reduced.

In other embodiments (not shown), the driving mechanism 200 is configured to drive the moving assembly 3 to reciprocate the second carrier 404 in the horizontal direction.

Therefore, the clamp is prevented from shaking or tilting in the test process, and the test accuracy is improved.

In one embodiment, the tensile fatigue test method of the coating is:

the paint test piece 400 is clamped in a clamp, the clamp is placed in an incubator 500 of the fatigue testing machine and is installed in place, the movable assembly 3 of the clamp is connected with the driving mechanism 200, and the supporting seat 1 and the fixed assembly 2 are fixed in the incubator 500 and kept still.

The paint test piece 400 is placed in an incubator 500 at-10 c 2 c for more than 1 hour. Then at this temperature, the driving mechanism 200 is turned on, and the moving assembly 3 is pulled to expand the width of the gap 408 between the first carrier 402 and the second carrier 404 to 2.5mm; then the operation is repeated 2000 times at a speed of expanding and contracting at a crack amplitude (i.e., the width of the gap 408 between the first carrier 402 and the second carrier 404) of 0.5mm to 2.5mm and a frequency of 5 times/min.

After 2000 cycles of the cyclic operation, the presence or absence of defects such as holes, cracks, breaks, etc. in the coating film at the slit 408 was visually observed in a state where the slit width (i.e., the width of the slit 408 between the first carrier 402 and the second carrier 404) was 2.5 mm.

In summary, the fatigue testing machine and the clamp thereof provided by the embodiment of the utility model can realize the tensile fatigue test of the paint test piece so as to evaluate the tensile fatigue performance of the paint, and are simple in structure, convenient to operate and suitable for popularization.

In the description of the present utility model, it should be noted that the terms "upper", "lower", "one side", "another side", "one end", "another end", "side", "opposite", "four corners", "periphery", "mouth" and "letter structure", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the structures referred to have a specific orientation, are configured and operated in a specific orientation, and thus are not to be construed as limiting the present utility model.

In the description of embodiments of the present utility model, unless explicitly stated and limited otherwise, the terms "connected," "directly connected," "indirectly connected," "fixedly connected," "mounted," "assembled" should be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; the terms "mounted," "connected," and "fixedly connected" may be directly connected or indirectly connected through intervening media, and may also be in communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Although the embodiments of the present utility model are described above, the embodiments are only used for facilitating understanding of the present utility model, and are not intended to limit the present utility model. Any person skilled in the art can make any modification and variation in form and detail without departing from the spirit and scope of the present disclosure, but the scope of the present disclosure is defined by the appended claims.

Claims (10)

1. The fixture is used for a fatigue testing machine and is characterized in that the fatigue testing machine is used for tensile fatigue testing of a coating test piece, the coating test piece comprises a first carrier, a second carrier and a coating to be detected, the coating to be detected is fixed on the first carrier and the second carrier, and the coating to be detected extends from the first carrier to the second carrier;

the clamp comprises:

a support base;

the fixing assembly is fixedly connected with the supporting seat and is used for fixing the first carrier to the supporting seat; and

the moving assembly is movably connected with the supporting seat and is arranged to movably connect the second carrier with the supporting seat, so that the second carrier can reciprocate relative to the first carrier, and a gap between the first carrier and the second carrier is circularly expanded and contracted to drive the part of the coating to be detected, which is positioned at the gap, to circularly stretch and contract.

2. The fixture of claim 1, wherein the fixture comprises a plurality of clamping plates,

the moving assembly comprises a first supporting plate and a first connecting plate, the first supporting plate is limited on the supporting seat, and the first connecting plate is arranged to be stacked on the first supporting plate at intervals so that the second carrier can be clamped between the first connecting plate and the first supporting plate; the first connecting plate is fixedly connected with the first supporting plate and matched with the second carrier to clamp the second carrier; the first connecting plate is arranged to drive the second carrier and the first supporting plate to reciprocate relative to the first carrier under the drive of the driving mechanism of the fatigue testing machine.

3. A jig according to claim 2, wherein,

the supporting seat is provided with a guide part, and the guide part is in limit fit with the first supporting plate and is arranged to guide the first supporting plate to linearly reciprocate along a first direction.

4. A clamp according to claim 3, wherein the guide comprises: a first rail and a second rail extending along the first direction;

the first guide rail and the second guide rail are arranged at intervals along a second direction perpendicular to the first direction;

the two ends of the first supporting plate in the second direction are respectively in sliding fit with the first guide rail and the second guide rail.

5. The fixture of claim 4, wherein the fixture comprises a plurality of clamping plates,

the first guide rail is provided with a first chute, one end of the first support plate along the second direction is accommodated in the first chute, and the first chute is also provided with a first avoiding groove which is recessed along the second direction towards a direction away from the first support plate;

the second guide rail is provided with a second chute, the other end of the first support plate along the second direction is contained in the second chute, and the second chute is also provided with a second avoiding groove which is recessed along the second direction towards the direction away from the first support plate.

6. The clamp of any one of claims 1 to 5, wherein the securing assembly includes a second support plate and a second connection plate, the second support plate being defined in the support seat, the second connection plate being arranged to be stacked in spaced relation to the second support plate such that the second carrier can be sandwiched between the second connection plate and the second support plate; the second connecting plate is fixedly connected with the second supporting plate and matched with and clamps the second carrier.

7. The clamp of claim 6, wherein the securing assembly further comprises a third connecting plate, the second connecting plate and the third connecting plate are disposed on opposite sides of the support base, the second connecting plate and the third connecting plate are fixedly connected by fasteners and clamp the support base, the second support plate and the second carrier.

8. A fatigue testing machine, comprising:

the clamp of any one of claims 1 to 7;

the driving mechanism is connected with the moving assembly of the clamp and is arranged to drive the moving assembly to reciprocate; and

the rack, actuating mechanism install in the frame, the supporting seat of anchor clamps is fixed in the frame.

9. The fatigue testing machine of claim 8, further comprising:

the constant temperature box is arranged in the rack, the clamp is positioned in the constant temperature box, and the driving mechanism is positioned outside the constant temperature box;

the connecting rod is arranged in the incubator in a penetrating mode, and the driving mechanism is connected with the clamp through the connecting rod.

10. The fatigue testing machine according to claim 8 or 9, wherein,

the driving mechanism is arranged to drive the moving assembly to drive the second carrier to reciprocate along the vertical direction; or alternatively

The driving mechanism is arranged to drive the moving assembly to drive the second carrier to reciprocate along the horizontal direction.