CN102928287B - Tensile jig for testing tensile properties of non-metallic materials - Google Patents

Abstract

The invention discloses a tensile clamp for a tensile property test of non-metal materials, and belongs to the technical field of tests on material performances. The tensile clamp has the structure that an upper holding rod is positioned at the upper part of an upper limiting block, and the upper holding rod is fixedly connected with the upper limiting block; the upper holding rod is connected with an upper connecting plate through a universal joint; the middle of the universal joint is connected with the upper limiting block and the lower end of the universal joint respectively through pins; the lower end of the universal joint and the upper connecting plate are fixedly connected together; the upper connecting plate and a splicing plate are fixedly connected together through bolts; an upper splicing face is a face of the upper splicing plate; a lower holding rod is positioned at the lower part of a lower limiting block, and the lower holding rod and the lower limiting block are fixedly connected together; the lower limiting block and a lower connecting plate are fixedly connected together; the lower connecting plate and a lower splicing plate are fixedly connected together through bolts; a lower splicing face is a face of the lower splicing plate; and scales for positioning test samples are carved on the lower splicing face. The tensile clamp has high precision, is safe to use, and can carry out test on the tensile strength of test samples with large sections.

Description

Tensile jig for testing tensile properties of non-metallic materials

technical field

The invention belongs to the technical field of material performance testing, and in particular relates to a tensile fixture for testing the tensile performance of non-metallic materials.

Background technique

Mechanical Testing & SimulationMTS is a well-known manufacturer of material testing machines, especially dynamic material testing machines. The 647-type wedge clamp for MTS testing machine, as shown in Figure 1, can be used to clamp sheet or cylindrical samples of different sizes by using the plane or V-shaped groove provided by the wedge after replacing different types of wedges. . However, the thickness or diameter of the sample clamped at this time is relatively small. For example, after the 647 wedge clamp is matched with different wedges, the maximum clamping thickness is 25.9mm, and the maximum clamping diameter is 26.2mm, of which 647.25 The maximum clamping diameter of the type wedge is 19.8mm. Therefore, if the tensile test of a large cross-section sample (such as a sample with a cross-sectional size of 100×100mm) is to be carried out, a separate fixture is required.

In order to realize the tensile performance test of large-section specimens, a tensile fixture matched with 647.25 wedges is urgently needed in practice.

No relevant literature on tensile clamps matching MTS company's 647.25 wedges was retrieved.

Contents of the invention

Aiming at the above-mentioned shortcomings in the prior art, the present invention proposes a tensile fixture for testing the tensile performance of non-metallic materials matched with the 647.25 wedge of the MTS testing machine.

The structure of the tensile fixture for the tensile performance test of a non-metallic material matched with the MTS testing machine 647.25 type wedge is as follows:

The clamp includes upper and lower parts, the upper part includes an upper limit block 1-2 and an upper grip rod 1-1 clamped by the testing machine wedge 0-2, which is used to adjust the tensile direction of the sample. Universal joint 1-5, upper connecting plate 1-7, upper bonding plate 1-8 and upper bonding surface 1-9 for bonding samples;

The upper holding rod 1-1 is located on the upper part of the upper limit block 1-2, the two are fixedly connected together, and the diameter of the upper limit block 1-2 is larger than the upper holding rod 1-1; The above-mentioned upper holding bar 1-1 is connected with the upper connecting plate 1-7 through the universal joint 1-5; The bit block 1-2 (with the function of the upper end of the universal joint 1-5) is connected with the lower end of the universal joint 1-4; the lower end of the universal joint 1-4 is fixedly connected with the upper connecting plate 1-7 Together; the upper connecting plate 1-7 and the upper bonding plate 1-8 are fixedly connected together by bolts; the upper bonding surface 1-9 is one surface of the upper bonding plate 1-8;

The lower part of the fixture includes a lower limit block 2-2, a lower grip rod 2-1 for being clamped by the testing machine wedge 0-2, a lower connecting plate 2-4, and a lower bonding plate 2-5 and the lower bonding surface 2-6 for bonding the specimen;

The lower holding rod 2-1 is located at the bottom of the lower limiting block 2-2, the two are fixedly connected together, and the diameter of the lower limiting block 2-2 is larger than that of the lower holding rod 2-1; The lower limiting block 2-2 and the lower connecting plate 2-4 are fixedly connected; the lower connecting plate 2-4 and the lower bonding plate 2-5 are fixedly connected together by bolts; the lower bonding surface 2 -6 is a surface of the lower adhesive plate 2-5, and the scale line 2-7 for sample positioning is engraved on the lower adhesive surface 2-6.

The diameter of the upper holding rod 1-1 is preferably 19mm, the height is preferably 80mm, the diameter of the upper limit block 1-2 is preferably 35mm, and the height is preferably 40mm; the diameter of the lower holding rod 2-1 Preferably 19mm, the height is preferably 80mm, the diameter of the lower limit block 2-2 is preferably 35mm, and the height is preferably 40mm;

The manufacturing materials of the fixture are selected from high-quality carbon structural steel except the upper bonding plate 1-8 and the lower bonding plate 2-5, and the upper bonding plate 1-8 and the lower bonding plate 2-5 use alloy structural steel Or alloy tool steel, supplemented by appropriate heat treatment process so that the hardness of the upper bonding surface 1-9 and the lower bonding surface 2-6 is not less than 55HRC;

The upper bonding surface 1-9 and the lower bonding surface 2-6 of the fixture should be smooth and flat, and the surface roughness parameter Ra is not greater than 0.80 microns;

After the preparation of the fixture is completed, it should be treated by boiling black to improve its antirust ability;

The universal joints 1-5 should rotate flexibly without blocking phenomenon.

The lower limit block 2-2 located at the lower part of the fixture can open the distance between the wedge top surface 0-5 and the lower connecting plate 2-4; the reason for adopting this measure is that the wedge-shaped fixture of the MTS testing machine Between 0-1 and wedge 0-2, there will be relative movement during the clamping process, resulting in the reduction of the distance between the top surface 0-4 of the wedge clamp and the top surface 0-5 of the wedge during the clamping process. The distance between the two top surfaces increases during the relaxation process, as shown in Figure 3. If there is no lower limit block 2-2, the distance between the surface of the lower connecting plate 2-4 facing the lower holding rod 2-1 and the top surface 0-4 of the wedge-shaped fixture may be too small during the installation of the fixture, making the test After the end, the clamping of the wedge 0-2 to the lower holding rod 2-1 cannot be loosened, resulting in a test accident;

There are scale marks 2-7 for sample positioning on the surface of the lower bonding surface 2-6 of the lower part of the fixture, which can be used to accurately bond the sample to the axis of the lower bonding surface 2-6, Improve the accuracy of test results;

The upper limit block 1-2 located on the upper part of the fixture has the function of limiting the clamping depth of the upper grip rod 1-1 in the wedge 0-2; the universal joint 1-5 can adjust the sample during the stretching process The direction in the center makes the sample stretch in the direction of its axis to avoid eccentric tension and ensure the accuracy of the test results;

The upper connecting plate 1-7, the upper bonding plate 1-8, the lower connecting plate 2-4 and the lower bonding plate 2-5 of the clamp are all fixedly connected by bolts, so that the bonding plate can be disassembled; The purpose of the detachable bonding plate is that before the test, a very strong glue (such as epoxy glue) is required between the sample and the bonding plate to bond, so that during the test, the tensile Destruction occurs on the sample itself rather than at the joint between the sample and the bonded plate; after the test is completed, because the bond between the sample and the bonded plate is very strong, it needs to be calcined at a high temperature Only by calcining the joint between the sample and the bonded plate can the bond between the bonded plate and the sample fail. Therefore, the detachable bonded plate is convenient for realizing the bond between the bonded plate and the sample after the test. High temperature calcination separation.

The beneficial effects of the present invention are:

The tensile fixture provided by the invention for testing the tensile performance of non-metallic materials has the characteristics of easy operation, flexible rotation, safe use and accurate positioning; the tensile process of large-section samples can be realized by using the fixture, and the anti-stretching of non-metallic materials can be realized. Testing of parameters such as tensile strength and fracture energy.

Description of drawings

Figure 1 is a schematic diagram of the 657 wedge clamp and 647.25 wedge of the MTS testing machine;

In the figure, 0-1 is the wedge-shaped fixture, 0-2 is the wedge, 0-3 is the piston, 0-4 is the top surface of the wedge-shaped fixture, and 0-5 is the top surface of the wedge;

Fig. 2 is a schematic structural view of the tensile clamp of the present invention; wherein,

Figure 2a is a schematic structural view of the upper part of the clamp;

In the figure, 1-1 is the upper grip rod, 1-2 is the upper limit block (and the upper end of the universal joint), 1-3 is the middle part of the universal joint, 1-4 is the lower end of the universal joint, and 1-5 is the universal joint Knuckles, 1-6 are holes for installing bolts on the upper connecting plate and the upper bonding plate, 1-7 are the upper connecting plate, 1-8 are the upper bonding plate, and 1-9 are the upper bonding surface; 1 -10 is the pin;

Fig. 2b is a structural representation of the lower part of the clamp;

2-1 is the lower holding rod, 2-2 is the lower limit block, 2-3 is the hole for installing bolts on the lower connecting plate and the lower bonding plate, 2-4 is the lower connecting plate, 2-5 is the lower Adhesive plate, 2-6 is the lower bonding surface, 2-7 is the scale line;

Fig. 3 is a schematic diagram of the relative movement between the 657-type wedge-shaped fixture of the MTS testing machine and the top surface of the 647.25 wedge; wherein,

Figure 3a is a schematic diagram of the 657 wedge clamp and 647.25 wedge of the MTS testing machine in the state of not clamping the tension clamp;

Figure 3b is a schematic diagram of the 657 wedge clamp and 647.25 wedge of the MTS testing machine in the state of clamping the tension clamp;

Fig. 4 is a schematic diagram of the working state of the tensile fixture of the present invention on the MTS testing machine.

Detailed ways

The tensile clamp of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

Example 1:

For example, the tensile strength test of a concrete sample is to be carried out.

First, the MTS testing machine is respectively used to clamp the clamping device of the upper part and the lower part of the clamp according to the present invention to an appropriate distance. After the tensile clamp is installed, the remaining space can place the sample to be tested. And there is a margin of 20-30mm;

Install the upper part and the lower part of the tensile fixture according to the present invention into the V-shaped groove of the wedge 0-2 of the MTS testing machine respectively, and clamp them, as shown in Figure 4; the specific installation process is as follows: First, insert the upper holding rod 1-1 of the upper part of the tensile fixture into the V-shaped groove of the wedge 0-2 until the upper limit block 1-2 faces the surface of the upper holding rod 1-1 and the wedge 0- 2 in contact with the top surface; then start the corresponding hydraulic switch on the MTS testing machine, so that the wedge 0-2 grips the upper grip rod 1-1; in the process of holding, the wedge-shaped fixture top surface 0-4 of the MTS testing The distance between 0-5 on the top surface of the wedge will be reduced by relative movement; then the lower part of the tensile fixture is installed on the MTS testing machine, and the installation process is the same as that of the upper part of the tensile fixture;

Apply the glue (such as epoxy glue) used to bond the concrete sample to the bonding surface of the tensile fixture on the lower bonding surface 2-6 of the tensile fixture, and then place the concrete sample on the lower bonding surface On the board 2-5, use the scale line 2-7 on the lower bonding surface 2-6 to position the concrete sample at the same time, so that the axis of the concrete sample is located in the center of the lower bonding surface 2-6; The resin glue is applied to the other side of the concrete sample;

Start the displacement control program of the MTS testing machine to shorten the distance between the upper and lower parts of the tensile fixture until the upper bonding surface 1-9 of the upper part of the tensile fixture is in contact with the epoxy resin glue applied on the upper end surface of the concrete sample. Contact, continue until the epoxy resin is squeezed out a little; then lock the state and continue for 24 hours, so that the epoxy resin is fully cured and produces sufficient bond strength;

After the epoxy resin glue is fully cured, start the test program of the MTS testing machine to stretch the concrete sample until the concrete sample breaks into two parts; in this process, the load change law during the stretching process is obtained;

After the test is completed, turn off the hydraulic switches that control the upper and lower parts of the tensile fixture in turn, open the grip of the wedge 0-2 to the holding rod, and glue the upper and lower parts of the tensile fixture together with them. The knotted concrete sample is removed from the clamping device of the MTS testing machine; by loosening the bolts on the upper connecting plate 1-7 and the lower connecting plate 2-4 of the tensile fixture, the upper bonding plate 1-8 and the lower connecting plate 2-4 are loosened. The lower bonding plate 2-5 is removed, and then the upper bonding plate 1-8 and the lower bonding plate 2-5 bonded with the concrete sample are put into a high-temperature furnace for calcination (usually the calcination temperature is 800-1000°C ), the duration of calcination is 10-20 minutes, so that the epoxy resin glue becomes invalid, and the separation of the concrete sample and the bonded plate is realized; finally, after the bonded surface is cleaned, it is restored and fastened to the corresponding connecting plate.

Claims (6)

1. a tensile clamp for non-metallic material tensile performance test, is characterized in that, described clamp structure is as follows: The clamp includes upper and lower parts, the upper part includes an upper grip rod (1-1), an upper limit block (1-2), a universal joint (1-5), an upper connecting plate (1-7), an upper bonding plate (1-8) and upper bonding surface (1-9); The upper holding rod (1-1) is located on the upper part of the upper limit block (1-2), the two are fixedly connected together, and the diameter of the upper limit block (1-2) is smaller than that of the upper holding rod (1-1) is large; the upper grip bar (1-1) is connected through the universal joint (1-5) and the upper connecting plate (1-7); the universal joint (1-5) The middle part of the universal joint (1-3) is respectively connected with the upper limit block (1-2) and the lower end of the universal joint (1-4) through pins (1-10); the lower end of the universal joint (1-4 ) and the upper connecting plate (1-7) are fixedly connected together; the upper connecting plate (1-7) and the upper adhesive plate (1-8) are fixedly connected together by bolts; the upper adhesive The joint surface (1-9) is a surface of the upper bonding plate (1-8); The lower part of the clamp includes a lower grip rod (2-1), a lower limit block (2-2), a lower connecting plate (2-4), a lower bonding plate (2-5) and a lower bonding surface ( 2-6); The lower holding rod (2-1) is located at the lower part of the lower limiting block (2-2), the two are fixedly connected together, and the diameter of the lower limiting block (2-2) is smaller than that of the lower holding rod (2-1) large; the lower limit block (2-2) and the lower connecting plate (2-4) are fixedly connected; the lower connecting plate (2-4) and the lower bonding plate (2-5 ) are connected together by bolts; the lower bonding surface (2-6) is a surface of the lower bonding plate (2-5), and the lower bonding surface (2-6) is engraved with useful Graduation marks (2-7) for specimen positioning. 2. The clamp according to claim 1, characterized in that, the diameter of the upper holding rod (1-1) is 19mm and the height is 80mm, and the diameter of the upper limit block (1-2) is 35mm and the height The diameter of the lower holding rod (2-1) is 19mm and the height is 80mm, and the diameter of the lower limit block (2-2) is 35mm and the height is 40mm. 3. The clamp according to claim 1, characterized in that, the manufacturing material of the clamp is high-quality carbon structural steel except the upper bonding plate (1-8) and the lower bonding plate (2-5); The upper bonding plate (1-8) and the lower bonding plate (2-5) use alloy structural steel or alloy tool steel. 4. The clamp according to claim 1, characterized in that the upper bonding surface (1-9) and the lower bonding surface (2-6) of the clamp should be smooth and flat, and the surface roughness parameter Ra is not Greater than 0.80 microns, hardness not less than 55HRC. 5. The clamp according to claim 1, characterized in that, after the clamp is prepared, it is treated by boiling black to improve its anti-rust ability. 6. The fixture according to claim 1, characterized in that, the universal joint (1-5) can rotate flexibly without stagnation.