CN102353578B - Testing device for two-way loading test of material - Google Patents

Abstract

The invention relates to a test device for bidirectional loading test of materials. The test device is composed of a base, a lever structure and a chuck. The base is arranged at the bottom, and the lever structure and the chuck are installed on the base. Compared with the prior art, the device of the present invention has a simple structure, is easy to maintain, can conveniently complete the test target, can conveniently adjust the loading ratio, and can realize the bidirectional loading test on the universal testing machine, reducing the test cost, and the device has sufficient loading capacity. advantages such as precision.

Description

A test device for bidirectional loading test of materials

technical field

The invention relates to a material testing device, in particular to a testing device for carrying out a bidirectional loading test on a plate-like sample of a composite material laminate.

Background technique

Composite materials are more and more widely used in the field of aviation, but most of the research on the strength of composite materials is still concentrated in the case of unidirectional loading. In practice, in most cases, composite materials are subjected to complex load. Obviously, it is far from enough to only study the strength under unidirectional loading. Whether it is to verify the strength criterion experimentally or to discuss the damage of composite materials under complex stress states from the perspective of damage, it is necessary to conduct bidirectional research on composite material samples. load test.

Biaxial loading test has not yet formed a standardized method. At present, bidirectional loading test is generally divided into two categories: (1) biaxial loading test using uniaxial loading system; (2) using two or more independent loading systems. Biaxial loading test.

The first category mainly includes off-axis tensile tests and bidirectional loading of cross-shaped test pieces using a certain mechanical structure.

1. Off-axis tensile test. Although this method can produce complex stress states for materials, the loading ratio that can be generated by this method depends on the fiber angle of the test piece and cannot be selected arbitrarily, so it is greatly limited.

2. Use a certain mechanical structure to carry out two-way loading on the cross-shaped test piece. This method is currently the focus of many scholars' research, but many design schemes have the defect that the loading ratio cannot be selected arbitrarily.

The second category mainly includes tension-compression and torsion or internal pressure/external pressure combined tests of thin-walled cylinders and biaxial loading tests on cross-shaped test pieces with two or more independent loading systems.

1. Tensile compression and torsion or internal pressure/external pressure combined test of thin-walled cylinders. The thin-walled cylinder test is a relatively common method, which can be loaded at any ratio. However, this method also has some disadvantages, such as the performance of tubular materials and plate materials are often different, a variety of elastic instability may occur during the loading process, and the impact of geometric deformation on the results during the loading process is often ignored;

2. Use two or more independent loading systems to conduct biaxial loading tests on the cross-shaped test piece. Although this test method can select any loading ratio for the test, the application of this method is limited due to the complex structure of the entire test equipment, high cost, and high requirements for the control system.

Contents of the invention

The object of the present invention is to provide a test device for bidirectional loading test of materials, which is simple in equipment structure, easy to maintain, and convenient to adjust the loading ratio in order to overcome the above-mentioned defects in the prior art.

The purpose of the present invention can be achieved through the following technical solutions:

A test device for two-way loading test of materials is composed of a base, a lever structure and a chuck. The base is arranged at the bottom, and the lever structure and the chuck are installed on the base.

The base includes slide rails, pulleys, chassis and bottom connectors, the pulleys are installed on the chassis, the slide rails are connected to the pulleys, the bottom connectors are arranged at the center of the bottom of the chassis, and the bottom connectors Universal testing machine can be connected.

Described pulley is provided with 8, evenly distributed on the outer circumference of chassis.

The lever structure includes a lever, a turnbuckle, a steel wire and a top connector. The lever has three stages, and the levers of each level are connected by a turnbuckle, and the steel wire is connected to the chuck by bypassing the pulley. , the top connecting piece is arranged on the top of the uppermost lever, and the top connecting piece can be connected to the universal testing machine.

The chuck is a self-tightening chuck installed on the slide rail on the base.

The maximum working load of the test device is 10KN.

The material of the test device is No. 45 steel.

The present invention can be installed on the universal testing machine through the upper and lower connecting parts, each arm of the specially designed test piece with eight arms is clamped by the chuck, and then the elastic nuts connected with the levers of all levels are adjusted to make each The level lever is kept in a horizontal state, and at the same time, each steel wire is guaranteed to be in the same tension state by adjusting the lowermost elastic nut.

The invention utilizes the principle of leverage, and can conveniently adjust the loading ratio. In addition to the equiaxed bidirectional loading test with a loading ratio of 1:1, it can also adjust the fixed position of the bolt on the lever, or replace the lever with a different size. Two-way loading tests with different loading ratios are realized.

Compared with the prior art, the present invention has the following advantages:

1. The equipment is simple in structure, easy to maintain, and can easily complete the test objectives;

2. It is convenient to adjust the loading ratio;

3. The bidirectional loading test can be realized on the universal testing machine to reduce the test cost;

4. The device has sufficient loading accuracy.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

In the figure, 1 is the bottom connector, 2 is the chassis, 3 is the pulley, 4 is the slide rail, 5 is the steel wire, 6 is the elastic nut, 7 is the first level lever, 8 is the second level lever, 9 is the third level Level lever, 10 is the top connector, 11 is the chuck, 12 is the test piece.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

A test device for two-way loading test of materials. Its structure is shown in Figure 1. It consists of three parts: a base, a lever structure, and a chuck 11. The base is set at the bottom, and the lever structure and chuck 11 are installed on the base. .

Among them, the bottom connector 1, the chassis 2, the pulley 3 and the slide rail 4 constitute the base; the steel wire 5, the turnbuckle 6, the first level lever 7, the second level lever 8, the third level lever 9 and the top connector 10 A lever structure is formed; the chuck 11 is installed on the slide rail 4 .

Pulley 3 is provided with 8, is evenly installed on the outer circumference of chassis 2, and slide rail 4 is connected with pulley 3, and bottom connector 1 is arranged on the center of bottom of chassis 2, and bottom connector 1 can connect universal testing machine. The first-level lever 7, the second-level lever 8, and the third-level lever 9 are connected from bottom to top through the elastic screw sleeve 6, the steel wire bypasses the pulley 3 and is connected to the chuck 11, and the top connecting piece 10 is arranged on the third-level lever 9, the top connector 10 can be connected to the universal testing machine. The collet 11 used is a self-tightening collet, which is installed on the slide rail 4 on the base.

The maximum working load of the test device is 10KN, and the material used is No. 45 steel.

The present invention can be installed on the universal testing machine by the bottom link 1 and the top link 10, each arm of the test piece with eight arms specially designed is clamped with the chuck, then adjusts the levers that are connected with all levels of levers The elastic nut keeps the levers at all levels in a horizontal state, and at the same time, by adjusting the elastic nut at the bottom, each steel wire is guaranteed to be in the same tension state.

The invention utilizes the principle of leverage, and can conveniently adjust the loading ratio. In addition to the equiaxial bidirectional loading test with a loading ratio of 1:1, it can also be adjusted by adjusting the fixed position of the bolt on the lever, or replacing the lever with a different size. Two-way loading tests with different loading ratios are realized.

Before carrying out the test, at first the top connecting piece 10 and the bottom connecting piece 1 are respectively fixed on the universal loading testing machine in the laboratory, then the test piece 12 with the strain gauge attached is clamped firmly with the chuck 11, and finally the joints are connected by adjusting The turnbuckle 6 of the level lever keeps the lever level, and the steel wires are in the same tension state, the testing machine is opened for loading, and the test data is obtained through the strain gauge. During the loading process, care should be taken to ensure that the loading is less than the design load of 10KN.

Claims (4)

1. A test device for carrying out material two-way loading test, it is characterized in that, this test device is made of base, lever structure, chuck three parts, and described base is located at the bottom, and described lever structure and chuck are installed on the base; The base includes slide rails, pulleys, chassis and bottom connectors, the pulleys are installed on the chassis, the slide rails are connected to the pulleys, the bottom connectors are arranged at the center of the bottom of the chassis, and the bottom connectors Can be connected to universal testing machine; The lever structure includes a lever, a turnbuckle, a steel wire and a top connector. The lever has three stages, and the levers of each level are connected by a turnbuckle, and the steel wire is connected to the chuck by bypassing the pulley. , the top connecting piece is arranged on the top of the uppermost lever, and the top connecting piece can be connected to the universal testing machine; The chuck is a self-tightening chuck installed on the slide rail on the base. 2. A test device for carrying out bidirectional loading tests on materials according to claim 1, characterized in that there are 8 pulleys, which are evenly distributed on the outer circumference of the chassis. 3. A kind of test device for carrying out material two-way loading test according to claim 1, is characterized in that, the working maximum load of this test device is 10KN. 4. A kind of test device for carrying out material two-way loading test according to claim 1, is characterized in that, the material of this test device adopts No. 45 steel.

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