CN112881160B

CN112881160B - Clamp for fatigue test of metal wide plate

Info

Publication number: CN112881160B
Application number: CN202110038343.7A
Authority: CN
Inventors: 马志阳; 曹学强; 高丽敏; 徐吉峰
Original assignee: Commercial Aircraft Corp of China Ltd; Beijing Aeronautic Science and Technology Research Institute of COMAC
Current assignee: Commercial Aircraft Corp of China Ltd; Beijing Aeronautic Science and Technology Research Institute of COMAC
Priority date: 2021-01-12
Filing date: 2021-01-12
Publication date: 2023-01-17
Anticipated expiration: 2041-01-12
Also published as: CN112881160A

Abstract

The invention provides a clamp for a metal wide plate fatigue test, relates to the technical field of metal fatigue test instruments, can realize clamping of a large wide plate fatigue test, prevents a metal wide plate from buckling in the fatigue test in advance, has good wide plate centering degree, and can remarkably improve test precision; the clamp comprises two clamping parts and an anti-buckling structure; the two clamping parts are arranged at two ends of the metal wide plate to be tested and have a clamping effect on the metal wide plate to be tested; the buckling-restrained structure is arranged between the two clamping parts; the clamping part comprises a clamping joint and two connecting belt plates; the two connecting belt plates are stacked in parallel, one end of each connecting belt plate is connected with the clamping joint in a pin mode, and the other end of each connecting belt plate is detachably and fixedly connected with the end portion of the metal wide plate to be measured; the buckling-restrained structure comprises two buckling-restrained plates which are respectively arranged on two sides of the metal wide plate to be tested and provided with crack observation areas, and the peripheries of the two buckling-restrained plates are detachably and fixedly connected. The technical scheme provided by the invention is suitable for the process of the metal plate fatigue test.

Description

Clamp for fatigue test of metal wide plate

Technical Field

The invention relates to the technical field of metal fatigue experimental instruments, in particular to a fixture for a metal wide plate fatigue test.

Background

In civil aircraft structures, aluminum alloy materials are widely applied, the fatigue life of the aluminum alloy materials has great influence on the structural design and service life of the aircraft, and the crack propagation rule of the aluminum alloy materials needs to be mastered through a fatigue test. The general fatigue testing machine does not provide a matched test fixture for an aluminum alloy wide plate or thin plate, the design is carried out according to the test requirement, the experiment efficiency is seriously reduced, and the fixture needs to be designed on site in each experiment, so that on one hand, the use of the fixture is not standard, even the fixture is clamped and fixed randomly, and the experiment effect is influenced; on the other hand, a large amount of resources are wasted, and the requirement of the era of energy conservation and environmental protection is not met.

Accordingly, there is a need to develop a metal wide plate fatigue test fixture that addresses the deficiencies of the prior art to solve or mitigate one or more of the problems set forth above.

Disclosure of Invention

In view of the above, the invention provides a clamp for a metal wide plate fatigue test, which can clamp a large wide plate fatigue test, prevent the metal wide plate from buckling in advance in the fatigue test, has good wide plate centering degree, and can remarkably improve the test precision.

On one hand, the invention provides a clamp for a metal wide plate fatigue test, which is characterized by comprising two clamping parts and an anti-buckling structure;

the two clamping parts are arranged at two ends of the metal wide plate to be detected and have a clamping effect on the end part of the metal wide plate to be detected;

the buckling-restrained structure is arranged between the two clamping parts and used for preventing the metal wide plate to be tested from buckling unstably in advance.

The above aspects and any possible implementations further provide an implementation in which the clamping portion includes one clamping tab and two connecting straps;

the two connecting band plates are stacked in parallel; and one end of each of the two connecting band plates is connected with the clamping joint by a pin, and the other end of each of the two connecting band plates is detachably and fixedly connected with the end part of the metal wide plate to be tested. The metal wide plate is preferably an aluminum alloy wide plate.

The above aspects and any possible implementations further provide an implementation, wherein the detachable fixed connection is a connection by fastening bolts.

The above aspect and any possible implementation manner further provide an implementation manner that the fastening bolts are distributed in two or more rows, and the number of the fastening bolts in each row is determined according to the test load, and is generally 3 or more.

In the above aspect and any possible implementation manner, there is further provided an implementation manner that the two connection strip plates are provided with notches into which the metal wide plates to be tested are inserted.

The above aspect and any possible implementation further provide an implementation in which both clamping portions are connected to a fatigue testing apparatus.

The above-mentioned aspects and any possible implementation manner further provide an implementation manner, in which the buckling-restrained structure includes two buckling-restrained plates that are respectively disposed on two sides of the metal wide plate to be tested and are provided with crack observation areas, and peripheries of the two buckling-restrained plates are detachably and fixedly connected with each other, and are used for performing plane clamping on the metal wide plate to be tested placed therebetween to prevent early buckling damage of the metal wide plate to be tested.

The above-mentioned aspect and any possible implementation manner further provide an implementation manner, wherein a side of the anti-buckling plate, which is in contact with the metal wide plate to be tested, is coated with a lubricant.

There is further provided in accordance with the above-described aspect and any one of the possible implementations, an implementation in which the clamp fitting includes a handle and a U-shaped portion, the handle being disposed at a non-open end of the U-shaped portion; the two overlapped connecting belt plates are inserted into the U-shaped part opening and are in pin joint with the U-shaped part; the handle is connected with fatigue test equipment.

Compared with the prior art, the invention can obtain the following technical effects: the clamp can solve the problem of clamping of a large wide plate in a fatigue test, and can prevent the metal wide plate from buckling in advance in the fatigue test; in addition, the clamp of the invention enables the large and wide plates to be measured to have good alignment degree, and obviously improves the test precision.

Of course, it is not necessary for any one product in which the invention is practiced to achieve all of the above-described technical effects simultaneously.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram of a clamp for a fatigue test of a wide metal plate according to an embodiment of the present invention in an unfolded state;

FIG. 2 is a schematic structural diagram of a clamping state of a clamp for a fatigue test of a metal wide plate according to an embodiment of the present invention;

fig. 3 is a schematic structural view of an anti-buckling plate provided in accordance with an embodiment of the present invention;

FIG. 4 is a block diagram of an upper clamp fitting provided in accordance with one embodiment of the present invention; wherein fig. 4 (a) is a front view and fig. 4 (b) is a side view;

FIG. 5 is a block diagram of an upper connecting pin provided in accordance with one embodiment of the present invention; wherein, fig. 5 (a) is a front view, and fig. 5 (b) is a perspective view;

FIG. 6 is a block diagram of a first upper connecting strap provided in accordance with one embodiment of the present invention; wherein fig. 6 (a) is a front view and fig. 6 (b) is a side view;

FIG. 7 is a three-dimensional view of a first anti-buckling plate provided in accordance with an embodiment of the present invention; fig. 7 (a) is a front view, fig. 7 (b) is a side view, and fig. 7 (c) is a bottom view.

Wherein, in the figure:

1. an upper clamping joint; 2. a pin shaft is connected; 3. a first upper connecting band plate; 4. the second upper connecting band plate; 5. an upper positioning pin; 6. a first anti-buckling plate; 7. a second anti-buckling plate; 8. a lower clamp fitting; 9. a lower connecting pin shaft; 10. a first lower connecting strap plate; 11. a second lower connecting band plate; 12. and a lower positioning pin.

Detailed Description

For better understanding of the technical solutions of the present invention, the following detailed descriptions of the embodiments of the present invention are provided with reference to the accompanying drawings.

It should be understood that the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

The invention belongs to 'engineering/structure, strength and material test/experimental technique/structure (including composite material) fatigue and damage tolerance test/experiment' in a Chinese commercial flight technical map. Aiming at the fatigue test of the aluminum alloy large-width plate, the invention forms a test fixture scheme by designing the clamping joint, the connecting pin shaft, the connecting belt plate and the anti-buckling device. The test fixture scheme can also be used for fatigue tests of other metal plates.

The clamp for the fatigue test of the metal wide plate can solve the problem of clamping of the fatigue test of the aluminum alloy wide plate, is suitable for the tension-compression fatigue, the tension-tension fatigue or the compression-compression fatigue test of the flat plate of the aluminum alloy wide plate, and can also be used for the fatigue test of other metal wide plates.

In the invention, the metal wide plate fatigue test fixture comprises: the metal wide plate fatigue test fixture comprises an upper clamping joint 1, an upper connecting pin shaft 2, a first upper connecting belt plate 3, a second upper connecting belt plate 4, an upper positioning pin 5, a first anti-buckling plate 6, a second anti-buckling plate 7, a lower clamping joint 8, a lower connecting pin shaft 9, a first lower connecting belt plate 10, a second lower connecting belt plate 11 and a lower positioning pin 12, and the metal wide plate fatigue test fixture is structurally shown in fig. 1.

The wide plate fatigue test fixture comprises an upper clamping end and a lower clamping end, and the upper clamping end and the lower clamping end play a role in clamping a wide plate to be tested together. Wherein, go up the exposed core and include that centre gripping connects 1, goes up connecting pin axle 2, connects on the first band board 3, connects on the second band board 4 and go up locating pin 5, as shown in fig. 2. The top of connecting band plate 3 on the first, connecting band plate 4 on the second all is equipped with the round pin hole, goes up the bottom that centre gripping connects 1 and also is equipped with the round pin hole. The first upper connecting belt plate 3 and the second upper connecting belt plate 4 are overlapped together and are in pin joint with the bottom end of the upper clamping joint 1 through the pin joint holes and the upper connecting pin shaft 2. The bottom of the contact surface of the first upper connecting belt plate 3 and the second upper connecting belt plate 4 is provided with a notch so as to insert the metal wide plate to be tested into the notch. The two upper connecting belt plates are connected with the metal wide plate to be measured through the upper positioning pins 5, and the metal wide plate is positioned.

The lower clamping end is similar to the upper clamping end in structure and comprises a lower clamping joint 8, a lower connecting pin shaft 9, a first lower connecting band plate 10, a second lower connecting band plate 11 and a lower positioning pin 12. The upper clamping end and the lower clamping end are respectively used for clamping two ends of the metal wide plate to be detected, so that the metal wide plate to be detected is clamped and fixed.

The metal wide plate fatigue test fixture further comprises a buckling-restrained structure which comprises a first buckling-restrained plate 6 and a second buckling-restrained plate 7, as shown in fig. 3. The first anti-bending plate 6 and the second anti-bending plate 7 are respectively arranged on two sides of the upper clamping end and the lower clamping end, namely on two sides of the metal wide plate to be measured. The two ends of the first buckling-restrained plate 6 are respectively connected with the upper clamping end and the lower clamping end, and the two ends of the second buckling-restrained plate 7 are also respectively connected with the upper clamping end and the lower clamping end to clamp the area to be tested of the metal wide plate to be tested, so that buckling of the metal wide plate to be tested is prevented. The first anti-bending plate 6 and the second anti-bending plate 7 are both plate-shaped, and openings are formed in the middle of the first anti-bending plate and the second anti-bending plate to expose part of the metal wide plate to be tested, so that the expansion condition of fatigue cracks on the metal wide plate to be tested can be observed conveniently.

The upper clamp fitting 1 is constructed as shown in figure 4, and the lower clamp fitting 8 is similar. The handle is a U-shaped structure with a handle, and pin joint holes corresponding to the positions and the sizes are formed in two side walls of the U-shaped structure and used for being in pin joint with an upper connecting belt plate or a lower connecting belt plate.

The upper connecting pin 2 is constructed as shown in fig. 5, and the lower connecting pin 9 is similar. The longitudinal section is T-shaped.

The first upper connecting band plate 3 is constructed as shown in fig. 6, and the second upper connecting band plate 4, the first lower connecting band plate 10 and the second lower connecting band plate 11 are similar thereto. The shape of the connection strip plate is not necessarily the shape shown in fig. 6, and may be another shape capable of clamping the wide metal plate to be measured. The clamping notch of the connecting belt plate is preferably consistent with the end part of the metal wide plate to be tested, namely square, so that the metal wide plate to be tested can be prevented from swinging left and right under the condition of pin joint, and the subsequent mechanical connection operation is facilitated.

The first anti-buckling plate 6 is structured as shown in fig. 7, and the second anti-buckling plate 7 is similar thereto. The size of the anti-buckling plate can be changed according to the size of the metal wide plate to be tested, and the anti-buckling plate is used for preventing buckling, so that the size of the anti-buckling plate can preferably completely cover the metal wide plate to be tested, and two side edges of the anti-buckling plate extend out, so that the two anti-buckling plates can be connected conveniently.

In the concrete structure, the upper clamping end is composed of an upper clamping joint 1, an upper connecting pin shaft 2, a first upper connecting band plate 3, a second upper connecting band plate 4 and an upper positioning pin 5, the clamping surface of the upper clamping joint is connected with a fatigue testing machine, and the first upper connecting band plate 3 and the second upper connecting band plate 4 are connected with the upper clamping joint 1 through the upper connecting pin shaft 2, as shown in fig. 2. When the upper end of an aluminum alloy large-width plate fatigue test piece is connected with a first upper connecting strip plate 3 and a second upper connecting strip plate 4, the upper connecting strip plate is positioned by an upper positioning pin 5, and then the mechanical connection is formed by inserting fasteners into 2 rows and 10 rows of fastening holes arranged slightly beside the positioning, and the upper positioning pin 5 does not transmit load and needs to be taken out after the fasteners are screwed. The connection form of the lower clamping end and the lower end of the aluminum alloy large-width plate fatigue test piece is the same as the above.

Since the aluminum alloy large-width plate test piece is generally a thin plate, a buckling-restrained device needs to be designed to prevent the test piece from being unstably damaged in advance, and the buckling-restrained device is formed by mechanically connecting a first buckling-restrained plate 6 and a second buckling-restrained plate 7 at the outer ends of two sides, as shown in fig. 3. In order to avoid affecting the test load transmission, it is necessary to apply lubricating oil to the surfaces of the inside of the first and second buckling

restrained plates

6 and 7 that are in contact with the test piece.

Because the upper connecting pin shaft 2 and the lower connecting pin shaft 9 provide the rotational degree of freedom, when the whole clamp is clamped on a testing machine, the centering degree can be adjusted through the rotation around the connecting pin shaft, and the testing precision is favorably improved.

In the aspect of fixture design and material selection, the upper clamping joint 1, the upper connecting pin shaft 2, the first upper connecting band plate 3, the second upper connecting band plate 4, the lower clamping joint 8, the lower connecting pin shaft 9, the first lower connecting band plate 10, the second lower connecting band plate 11 and the connecting bolts (i.e. fasteners) are recommended to be made of high-strength alloy steel so as to ensure the connecting strength. The upper and lower locating pins 5, 12 may be made of ordinary steel. The first and second buckling

preventive plates

6 and 7 are preferably made of a thick plate of aluminum alloy, and can ensure a certain rigidity and reduce the weight.

The clamp for the fatigue test of the metal wide plate provided by the embodiment of the application is described in detail above. The above description of the embodiments is only for the purpose of helping to understand the method of the present application and its core ideas; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

As used in the specification and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The description which follows is a preferred embodiment of the present application, but is made for the purpose of illustrating the general principles of the application and not for the purpose of limiting the scope of the application. The scope of the present application is to be construed in accordance with the substance defined by the following claims.

It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of additional like elements in a commodity or system comprising the element.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

The foregoing description shows and describes several preferred embodiments of the present application, but as aforementioned, it is to be understood that the application is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the application as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the application, which is to be protected by the claims appended hereto.

Claims

1. The clamp for the fatigue test of the metal wide plate is characterized by comprising two clamping parts and an anti-buckling structure;

the two clamping parts are arranged at two ends of the metal wide plate to be tested and have a clamping effect on the end part of the metal wide plate to be tested;

the buckling-restrained structure is arranged between the two clamping parts and is used for preventing the metal wide plate to be tested from buckling unstably in advance;

the clamping part comprises a clamping joint, two connecting belt plates, a connecting pin shaft and a positioning pin;

the two connecting band plates are stacked in parallel; one end of each of the two connecting belt plates is connected with the clamping joint through a connecting pin shaft in a pin joint mode, and the other end of each of the two connecting belt plates is detachably and fixedly connected with the end portion of the metal wide plate to be tested; the connecting pin shaft provides a rotational degree of freedom, and when the whole clamp is clamped on a testing machine, the centering degree is adjusted through rotation around the connecting pin shaft, so that the testing precision is improved;

the two connecting band plates are provided with notches into which the metal wide plates to be tested are inserted; the shape of the notch is consistent with that of the end part of the metal wide plate to be tested and is square, so that the metal wide plate to be tested is prevented from swinging left and right under the condition of pin joint, and the subsequent mechanical connection operation is facilitated;

when connecting a large-width plate fatigue test piece of aluminum alloy and two connecting belt plates, positioning through a positioning pin, and then inserting a fastener into a fastening hole arranged slightly beside the positioning to form mechanical connection, wherein the positioning pin does not transmit load and needs to be taken out after the fastener is screwed;

the buckling-restrained structure comprises two buckling-restrained plates which are respectively arranged at two sides of the metal wide plate to be detected and are provided with crack observation areas, and the peripheries of the two buckling-restrained plates are mutually detachably and fixedly connected; the size of the anti-buckling plate can completely cover the metal wide plate to be tested, and two side edges of the anti-buckling plate extend out, so that the two anti-buckling plates can be connected conveniently;

a lubricant is coated on one side of the anti-buckling plate, which is in contact with the metal wide plate to be tested, so that the test load transmission is prevented from being influenced;

the buckling-restrained plate is made of an aluminum alloy thick plate, so that certain rigidity is guaranteed, and the weight is reduced.

2. The metal wide plate fatigue test fixture of claim 1, wherein the detachable fixed connection is a connection by fastening bolts.

3. The metal wide plate fatigue test jig according to claim 2, wherein the distribution of the fastening bolts is two or more rows, and the number of the fastening bolts in each row is determined according to the test load.

4. The metal wide plate fatigue test jig according to claim 1, wherein both the clamping portions are connected to a fatigue test device.

5. The metal wide plate fatigue test fixture of claim 1, wherein the clamping joint comprises a handle and a U-shaped portion, the handle being disposed at a non-open end of the U-shaped portion; the two overlapped connecting belt plates are inserted into the U-shaped part opening and are in pin joint with the U-shaped part; the handle is connected with fatigue test equipment.