CN115326550A - Clamping device and method for quasi-static indentation test of material - Google Patents

Abstract

The invention discloses a clamping device and method for quasi-static indentation test of materials, belonging to the field of complex load testing of composite materials. The angle between the two vertical support plates and the horizontal support plate is a right angle; the fixture base platform is designed with a rectangular limit slot, and the fixture cover plate and the fixture base platform have square holes of the same size and position; the fixture cover plate Set the bolt holes evenly at the same location near the outer edge of the plane as the fixture base platform. The fixture of the invention can not only realize the edge support boundary condition consistent with the low-speed impact test to the maximum extent, but also can arrange a camera inside the fixture to record the destruction process of the test piece in real time during the quasi-static indentation test. In addition, the clamping device has the advantages of simple structure, easy use, convenient testing, low cost and the like.

Description

A clamping device and method for quasi-static indentation test of materials

technical field

The invention relates to a loading device and method for a material quasi-static indentation test, belonging to the field of complex load testing of composite materials.

Background technique

Advanced composite materials have excellent characteristics such as high specific stiffness and specific strength, and also have good heat insulation, sound insulation, low cost, light weight, and high integrity. Compared with isotropic materials, they are more suitable for marine, aerospace, Aeronautics, automobiles, construction and other engineering fields. Such composite materials are sensitive to impact loads, and are often impacted by foreign objects at low speeds during the manufacture, use and maintenance of materials. Under such impact conditions, fiber/matrix damage that cannot be observed by naked eyes is very easy to occur inside the structure, and this damage is more harmful to the performance of materials than high-speed impact damage to some extent.

Therefore, it is necessary to study the post-impact performance of composite materials to provide guidance for industrial design. Low-velocity impact tests usually last for a short period of time, so it is difficult to study the damage mode of a specific damage mode, and it is not easy to measure the dynamic contact force and deformation of the panel due to the limitation of test conditions. But the quasi-static indentation test is more advantageous because it is easier to obtain more data, and the same damage mode as the low-velocity impact can be reproduced using the quasi-static indentation test by gradually applying the displacement load.

Contents of the invention

In order to solve the problems in the prior art, the present invention provides a clamping device for quasi-static indentation test of material edge support. The device of the present invention is simple in structure, easy to use and convenient to test, and solves the above-mentioned technical defects.

The present invention is achieved like this:

A clamping device for quasi-static indentation testing of materials, characterized in that the clamping device includes a clamp base platform, and the upper and lower ends of the clamp base platform are respectively connected as a clamp cover plate and a U-shaped support of the base; The U-shaped support of the base includes two vertical support plates and a horizontal support plate. The angle between the two vertical support plates and the horizontal support plate is a right angle, forming a space where photographic equipment can be placed.

The upper surface of the fixture base platform contains a rectangular limiting groove for the quasi-static compression test piece, which limits the test piece to be kept in the center of the fixture.

The four right angles of the rectangular limiting groove are additionally widened the circular counterbore; the rectangular test piece is placed in the rectangular limiting groove, and the fixture cover plate and the fixture base platform are connected by bolts to realize the edge support of the test piece ; The geometric center of the test piece and the geometric center of the fixture platform are on a vertical line.

Further, the clamp cover plate and the clamp base platform are uniformly provided with bolt holes at the same position close to the outer edge of the plane; the clamp cover plate and the clamp base platform have square holes of the same size and position; the clamp cover plate and the clamp base pass through Bolted.

Further, the U-shaped support of the fixture base is used to connect the testing machine and the fixture base platform, and the two vertical support plates and the horizontal support plates of the U-shaped support form a space between the testing machine platform and the fixture base platform; There is a circular counterbore on the horizontal support plate.

Further, the circular counterbore is used to place the rubber pad and the camera, and the camera is located below the center of the test piece.

A kind of loading method of the clamping device that is used for material quasi-static indentation test of the present invention comprises the following process:

Step 1. Cut the material into a 100mm*150mm rectangular test piece;

Step 2. Place the rectangular test piece in the rectangular limit slot of the fixture base platform;

Step 3. Cover the fixture cover on the test piece, and connect the fixture cover and the base platform with bolts;

Step 4. Place the cut rubber pad in the prototype sink hole of the U-shaped support of the fixture base, then place the camera on the rubber pad, adjust the viewing angle of the camera, and align it with the center of the lower surface of the test piece;

Step 5. Place the fixture on the universal testing machine and adjust the alignment position;

Step 6. Operate the testing machine to adjust the contact gap between the loading head and the test piece, so that the test piece is in a slightly compressed state;

Step 7. Set the loading rate according to different test piece materials, conduct quasi-static indentation test, and record the deformation and damage during the test through the camera.

The beneficial effect of the present invention compared with prior art is:

The test fixture of the present invention can not only realize the edge support boundary conditions consistent with the low-speed impact test to the greatest extent, but also can arrange a camera inside the fixture to record in real time the destruction process of the test piece during the quasi-static indentation test. In addition, the clamping device has the advantages of simple structure, easy use, convenient test, and low cost.

Because the device of the present invention is simple in structure, it is convenient for processing and maintenance, and can conveniently complete the test task; the shape of the test piece is easy to process and does not require special processing shapes; it can realize edge-supported quasi-static indentation tests on the universal testing machine, and the test cost is low. Low; real-time recording of the damage process of the test piece during the quasi-static indentation test.

Description of drawings

Fig. 1 is the schematic diagram of the edge support quasi-static indentation test clamping device of the clamping device used for material quasi-static indentation test of the present invention;

Fig. 2 is the plan view and the front view of the clamp base in the clamping device used in the material quasi-static indentation test of the present invention;

Fig. 3 is the schematic cross-sectional view of the clamping device when the clamping device used for the quasi-static indentation test of materials according to the present invention carries out the quasi-static indentation test;

Among them, 1-fixture cover plate, 2-bolt hole, 3-rectangular limit slot, 4-fixture base platform, 5-base U-shaped support, 6-circular counterbore, 7-camera, 8-rubber pad, 9 -Loading head.

Detailed ways

In order to make the object, technical solution and effect of the present invention clearer and clearer, the following examples are given to further describe the present invention in detail. It should be pointed out that the specific implementations described here are only used to explain the present invention, not to limit the present invention.

A clamping device for quasi-static indentation test of materials, its structure as shown in Figure 1 and Figure 2, the present invention consists of a clamp cover 1 and a clamp base, the clamp base consists of a base platform 4 and a base U Type support 5 constitutes; The base U-shaped support 5 includes two vertical support plates and a horizontal support plate, and the angle between the two vertical support plates of the base U-shaped support 5 and the horizontal support plate is a right angle; the clamp cover plate 1 and the fixture base platform 4 are evenly provided with bolt holes 2 at the same position close to the outer edge of the plane; the fixture cover plate and the fixture base platform have square holes with the same size and position; the fixture cover plate 1 and the fixture base platform 4 are connected by bolts . The upper surface of the fixture base platform 4 includes a quasi-static compression test piece rectangular limit groove 3; the four right angles of the rectangular limit groove are respectively widened circular counterbore; the rectangular test piece is placed in the rectangular limit groove 3, and the fixture cover plate 1 and the fixture base platform 4 are connected by bolts; the geometric center of the test piece and the geometric center of the fixture base platform 4 are on a vertical line. The U-shaped support 5 of the clamp base is used to connect the testing machine and the clamp base platform 4, and the two vertical support plates and the horizontal support plates of the U-shaped support form a space between the testing machine platform and the clamp base platform; There is a circular counterbore 6 on the horizontal support plate for placing a rubber pad 8 and a camera 7, and the camera 7 is located below the center of the test piece.

A clamping device and a loading method for a material quasi-static indentation test, characterized in that it includes the following process:

Step 1. Cut the material into a 100mm*150mm rectangular test piece;

Step 2. Place the rectangular test piece in the rectangular limit slot of the fixture base platform;

Step 3. Cover the fixture cover on the test piece, and connect the fixture cover and the base platform with bolts;

Step 4. Place the cut rubber pad in the prototype sink hole of the U-shaped support of the fixture base, then glue the camera to the rubber pad, adjust the camera angle of view, and align it with the center of the lower surface of the test piece;

Step 5. Place the fixture on the universal testing machine and adjust the alignment position;

Step 6. Operate the testing machine to adjust the contact gap between the loading head 9 and the test piece, so that the test piece is in a slightly compressed state;

Step 7. Set the loading rate according to different test piece materials, conduct quasi-static indentation test, and record the deformation and damage during the test through the camera.

The above description is only a preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements can also be made, and these improvements should also be regarded as the present invention. protection scope of the invention.

Claims (5)

1. A clamping device for a material quasi-static indentation test is characterized by comprising a clamp base platform (4), wherein the upper end and the lower end of the clamp base platform (4) are respectively connected with a clamp cover plate (1) and a base U-shaped support (5); the U-shaped support (5) of the base comprises two vertical support plates and a horizontal support plate, and the included angle between the two vertical support plates and the horizontal support plate is a right angle;

the upper surface of the clamp base platform (4) comprises a rectangular limiting groove (3) for placing a quasi-static indentation test piece; four right angles of the rectangular limiting groove are respectively provided with an additionally widened circular counter bore; the rectangular test piece is placed in the rectangular limiting groove and fixedly connected with the clamp cover plate (1) and the clamp base platform (4) (through bolts); the geometric center of the test piece and the geometric center of the clamp platform are on the same vertical line.

2. The clamping device for the quasi-static indentation test of materials according to claim 1, characterized in that the clamp cover plate (1) and the clamp base platform (4) are uniformly provided with bolt holes (2) at the same positions close to the outer edge of the plane; the clamp cover plate (1) and the clamp base platform (4) are provided with square holes with the same size and position; the clamp cover plate is connected with the clamp base through a bolt.

3. The clamping device for the quasi-static indentation test of the material according to claim 1, characterized in that the U-shaped support (5) of the fixture base is used for connecting the testing machine with the fixture base platform (4), and two vertical support plates and a horizontal support plate of the U-shaped support form a space between the testing machine platform and the fixture base platform; the horizontal supporting plate is provided with a circular counter bore (6).

4. The clamping device for the quasi-static indentation test of the material according to claim 3, characterized in that the circular counter bore (6) is used for placing a rubber pad (8) and a camera (7), and the camera (7) is positioned below the center of the test piece.

5. The clamping device for the quasi-static indentation test of the material as claimed in any one of claims 1 to 4, wherein the loading method of the clamping device comprises the following steps:

step 1, cutting the material into rectangular test pieces of 100mm/150mm;

step 2, placing a rectangular test piece in a rectangular limiting groove of a clamp base platform;

step 3, covering a clamp cover plate on the test piece, and connecting the clamp cover plate with the base platform through bolts;

step 4, placing the cut rubber pad in a circular counter bore of a U-shaped support of a clamp base, then placing a camera on the rubber pad, adjusting the visual angle of the camera, and aligning the camera to the center of the lower surface of the test piece;

step 5, placing the clamp on a universal testing machine, and adjusting the centering position;

step 6, operating the testing machine to adjust the contact gap between the loading pressure head and the test piece, so that the test piece is in a micro-compression state;

and 7, setting loading rates according to different test piece materials, performing a quasi-static indentation test, and recording deformation and damage in the test process through a camera.

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