CN111044363A - Biaxial tension experimental device with variable load ratio - Google Patents
Biaxial tension experimental device with variable load ratio Download PDFInfo
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- CN111044363A CN111044363A CN201911251601.9A CN201911251601A CN111044363A CN 111044363 A CN111044363 A CN 111044363A CN 201911251601 A CN201911251601 A CN 201911251601A CN 111044363 A CN111044363 A CN 111044363A
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- biaxial tension
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
Abstract
The invention relates to a biaxial tension experimental device with variable load ratio, which comprises: a support; the rail type cross base is fixed on the bracket; the sliding block is arranged on the track of the track type cross base; the quick-change wedge block is fixed on the sliding block, is provided with various specifications, and can be selected according to the tensile load ratio requirement; the roller is contacted with the inclined surface of the quick-change wedge block in the pressing process; the cross-shaped pressure head is connected with the roller and used for pressing down the roller; the bidirectional tensile test sample is placed on the rail type cross base and is fixed on the sliding block through a test sample positioning pin; and the high-speed camera is aligned with the biaxial tension sample and is used for shooting the surface of the sample sprayed with the speckle pattern. Compared with the prior art, the invention has the advantages of wide application range, high test accuracy and the like.
Description
Technical Field
The invention relates to a material tensile property experimental device, in particular to a biaxial tension experimental device with a variable load ratio.
Background
In order to accurately predict the forming problem of the plate in the stamping process, the mechanical properties of the material in different stress states need to be known, and the traditional uniaxial material testing machine is difficult to test the mechanical properties of the material in a bidirectional tensile stress state. At present, a hydraulic or mechanical experimental device is mainly used for the biaxial tension experiment, but the hydraulic experimental device has a complex structure and higher manufacturing cost. The mechanical biaxial tension experimental device can meet the requirement of unidirectional loading and biaxial tension, has low manufacturing cost and reliable structure and is widely applied to biaxial tension experiments.
The top of the existing mechanical biaxial tension experimental device is matched with a roller by a cross pressure head for use, according to the vector synthesis and decomposition principle of speed, the roller is pressed down by the pressure head and is abutted to the inclined surface of the wedge block to push the wedge block to move outwards, meanwhile, the wedge block drives a clamp to move outwards so as to realize the test requirement of biaxial tension, and the angle for replacing the wedge block can realize biaxial tension experiments with different load ratios.
However, because the four rollers on the cross-shaped pressure head are always positioned on the same plane, when the wedge block is replaced, the four rollers and the inclined planes of the four wedge blocks are required to be simultaneously contacted when the pressure head is pressed down, otherwise, the situation that stretching deformation occurs in advance in a certain direction and deformation does not occur in the other direction occurs yet. In addition, the sample is fixed by clamping the sample by the clamp, so that the center of the sample is difficult to be ensured in the loading direction of a pressure head, the strength of the existing material is higher and higher, and the phenomenon that the sample slips due to insufficient clamping force is easy to occur when part of high-strength steel is subjected to a tensile test, so that the accuracy of the mechanical property test result of the material is influenced.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, provides the biaxial tension experimental device with the variable load ratio, wide application range and high test accuracy, and is used for solving the problems of complicated wedge block replacement and inaccurate positioning when the conventional mechanical biaxial tension experimental device is used for carrying out tensile experiments with different proportions; and the problems of sample slipping and unsynchronized stress in four directions during stretching.
The purpose of the invention can be realized by the following technical scheme:
a biaxial tension experimental device with variable load ratio comprises:
a support;
the rail type cross base is fixed on the bracket;
the sliding block is arranged on the track of the track type cross base;
the quick-change wedge block is fixed on the sliding block, is provided with various specifications, and can be selected according to the tensile load ratio requirement;
the roller is contacted with the inclined surface of the quick-change wedge block in the pressing process;
the cross-shaped pressure head is connected with the roller and used for pressing down the roller;
the bidirectional tensile test sample is placed on the rail type cross base and is fixed on the sliding block through a test sample positioning pin;
and the high-speed camera is aligned with the biaxial tension sample and is used for shooting the surface of the sample sprayed with the speckle pattern.
Preferably, the rail-mounted cross base is provided with a roller, and the sliding block is connected with the roller in a sliding manner.
Preferably, the rail-mounted cross base is provided with four grooves, a T-shaped key groove for fixing the sliding block is formed in each groove, and the sliding block slides along the inner part of each groove under the constraint of the T-shaped key groove.
Preferably, two right-angle sides of a triangular area of the quick-change wedge block are set to be in different proportions.
Preferably, three sample positioning pins are adopted on each slide block to fix the biaxial tension sample.
Preferably, the device further comprises a vertical baffle, and the quick-change wedge block is connected with the vertical baffle through a T-shaped key and then fixed on the sliding block.
Preferably, the device further comprises a positioning bolt for pushing the vertical baffle and the quick-change wedge block to move in the sliding block and adjusting the distance between the quick-change wedge block and the roller.
Preferably, the initial positions of the quick-change wedge blocks and the vertical baffle are determined by the screwing depth of the positioning bolt, and the inclined surface of each quick-change wedge block is adjusted to be just contacted with the roller by the positioning bolt.
Preferably, the high-speed camera is positioned right below the biaxial tension sample and is provided with two shadowless lamps.
Preferably, the support is arranged right below the four grooves of the rail-type cross base.
Compared with the prior art, the invention has the following advantages:
utilize the difference of two right-angle sides length ratio in quick change formula wedge triangle-shaped region, realize the biaxial tension experiment of different load ratios on traditional universal material testing machine, can realize that the load ratio has: 1:1, 1:4, 1:2, 1:3, 2:3 and 3:4, and meanwhile, the quick-change wedge block realizes quick change and reliable positioning in a T-shaped key mode; the distance between the quick-change wedge block and the cross pressure head roller can be adjusted by adjusting the screwing depth of the positioning bolt, so that the four quick-change wedge blocks are ensured to be in contact with the roller at the same time, and the four directions of the sample are always stressed at the same time; in addition, the sample is positioned in a mode that the sample clamping end is punched and matched with the positioning pin, the center of the sample is ensured to be positioned in the loading direction of the cross-shaped pressure head, and the sample slipping caused by insufficient clamping force is avoided. The device also comprises a high-speed camera and a shadowless lamp, and an external DIC processing device can acquire the deformation condition of the sample in the whole test process to obtain reliable material mechanical property data.
Drawings
FIG. 1 is a schematic view of the overall structure of a biaxial tension experimental device with a variable load ratio according to the present invention;
FIG. 2 is a half sectional view of the structure of the biaxial tension test device with variable load ratio of the present invention;
FIG. 3 is a front view of the assembly of some key components of the biaxial tension testing apparatus with variable load ratio of the present invention;
FIG. 4 is a left side view of FIG. 3;
FIG. 5 is a sectional view taken along line A-A of FIG. 3;
fig. 6 is a schematic view of a biaxial tension sample of a sheet material used in the present invention.
In the figure, the symbols represent: the method comprises the following steps of 1-a cross pressure head, 2-a roller, 3-a quick-change wedge block, 4-a vertical baffle, 5-a slide block, 6-a positioning bolt, 7-a roller, 8-a rail type cross base, 9-a bracket, 10-a sample positioning pin, 11-a biaxial tension sample, 12-a high-speed camera and 13-a shadowless lamp.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.
The biaxial tension experimental device with different load ratios provided by the embodiment of the invention can be used for carrying out experiments on a common press machine and is used for biaxial tension tests of metal or nonmetal materials, the tensile load ratio can be changed by replacing the quick-change wedge block in the stretching process, and meanwhile, the stretching speed in each direction is kept unchanged.
As shown in fig. 1, the biaxial tension experimental device with the variable load ratio comprises a cross pressure head 1, a roller 2, a quick-change wedge block 3, a vertical baffle 4, a slide block 5, a positioning bolt 6, a roller 7, a rail-type cross base 8, a bracket 9, a sample positioning pin 10, a biaxial tension sample 11 and a high-speed camera 12.
The sample is fixed on the sliding block 5 through the sample positioning pin 10, the sliding block 5 is accurately positioned by means of the size of the sample, the center of the sample is ensured to be in the loading direction of the cross-shaped pressure head 1, and meanwhile, the sample positioning pin 10 can prevent the sample from slipping due to insufficient clamping force during stretching; the angle and distance of the high-speed camera 12 are adjusted so that the surface of the sample sprayed with the speckle pattern can be clearly and effectively shot.
The slide block 5 is fixed on the track through a T-shaped groove arranged on a track type cross base 8 and slides on the roller 7 along the track.
Different quick-change wedge blocks 3 are selected according to the tensile load ratio requirement, the quick-change wedge blocks are connected with the vertical baffle 4 through T-shaped keys, the vertical baffle 4 and the wedge blocks 3 are fixed on the sliding block 5 through the T-shaped keys, and the vertical baffle 4 and the wedge blocks 3 can slide on the sliding block 5 along the T-shaped key track direction, which is shown in the figure 3-5.
According to the vector synthesis and decomposition of motion, the double-pull experiment with different load ratios can be realized by only replacing wedge blocks with different slopes, as shown in fig. 5, the quick-change wedge blocks with a/b of 1:1, 1:4, 1:2, 1:3, 2:3 and 3:4 are processed, wherein a is high and b is long, and the wedge blocks are replaced by a laboratory according to the load ratio requirement.
The cross pressure head 1 is properly pressed down until a certain pair of rollers 2 is contacted with the inclined surface of the quick-change wedge-shaped block 3, the distance between the inclined surface of the wedge-shaped block 3 and the other pair of rollers 2 is adjusted by adjusting the screwing-in depth of the positioning bolt 6 until the inclined surface is contacted, and thus the simultaneous stress of the two directions of the sample can be ensured.
In the sample deformation process, the high-speed camera 12 is matched with the shadowless lamp 13 to photograph the double-pull sample sprayed with the speckle patterns, and the external DIC processing equipment can eliminate errors caused by sample reflection to obtain accurate deformation information.
The main innovation points of the invention also comprise:
1. the rail-mounted cross base is provided with the roller, friction force borne by the sliding block when the sliding block slides on the roller is rolling friction, so that the influence of the friction force in the experimental process is greatly reduced, in the prior art, the friction force borne by the general sliding block when the sliding block moves is sliding friction, the friction force is large, and locking can be caused when the inclination angle between the hammer head and the lower end surface is not properly selected;
2. in the invention, when a sample is fixed, each end is fixed by adopting three positioning pins, and when the sample is stretched, the three positioning pins are stressed simultaneously, so that the stress uniformity of a straight arm part of the sample is ensured;
3. according to the invention, a sample is fixed on a sliding block, the sliding block and a base are matched in a T-shaped key manner, the sliding block can only move along a stretching direction, a stretching arm in the prior art is generally cylindrical and is only fixed on the sliding block through one screw, the stretching arm is not restrained enough, the stretching arm can rotate around the stretching direction, and torsional deformation is introduced to the sample during stretching;
4. the high-speed camera is positioned under the sample and is provided with the two shadowless lamps, the error caused by sample reflection can be effectively eliminated by utilizing the external DIC processing equipment, the focusing is convenient, a reflector is generally required to be arranged in the prior art, the focusing operation is not facilitated, and the error caused by sample reflection cannot be eliminated.
5. According to the invention, the wedge-shaped block and the vertical baffle can move on the sliding block under the pushing of the positioning bolt, so that the distance between the inclined surface of the wedge-shaped block and the roller carried by the pressure head can be adjusted, and the four rollers are ensured to be in contact with the wedge-shaped block at the same time. On general gyro wheel snap-on in prior art was in the slider, the distance on fixed back unable adjusting roller of sample and tup inclined plane easily caused two directions atress asynchronous when warping.
While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A biaxial tension test device with a variable load ratio, comprising:
a support (9);
the rail type cross base (8) is fixed on the bracket (9);
the sliding block (5) is arranged on a track of the track type cross base (8);
the quick-change wedge block (3) is fixed on the sliding block (5), is provided with various specifications, and can be selected according to the tensile load ratio requirement;
the roller (2) is contacted with the inclined surface of the quick-change wedge block (3) in the pressing process;
the cross pressure head (1) is connected with the roller (2) and is used for pressing the roller (2) downwards;
the bidirectional tensile test sample (11) is placed on the rail-type cross base (8) and is fixed on the sliding block (5) through a test sample positioning pin (10);
and the high-speed camera (12) is aligned with the biaxial tension sample (11) and is used for shooting the surface of the sample sprayed with the speckle pattern.
2. The biaxial tension test device with the variable load ratio as claimed in claim 1, wherein the rail-type cross base (8) is provided with rollers (7), and the slide block (5) is connected with the rollers (7) in a sliding manner.
3. The biaxial tension test device with the variable load ratio as claimed in claim 1, wherein the rail-type cross base (8) is provided with four grooves, a T-shaped key groove for fixing the sliding block (5) is formed in each groove, and the sliding block (5) slides along the inner part of each groove under the constraint of the T-shaped key groove.
4. The biaxial tension test device with the variable load ratio as claimed in claim 1, wherein two right-angled sides of the triangular area of the quick-change wedge-shaped block (3) are set to different proportions.
5. The biaxial tension test device with the variable load ratio according to claim 1, characterized in that three sample positioning pins (10) are used on each slide block (5) to fix the biaxial tension sample (11).
6. The biaxial tension test device with the variable load ratio as claimed in claim 1, wherein the device further comprises a vertical baffle (4), and the quick-change wedge-shaped block (3) is connected with the vertical baffle (4) through a T-shaped key and then fixed on the sliding block (5).
7. A biaxial tension test device with variable load ratio as claimed in claim 6, characterized in that the device further comprises a positioning bolt (6) for pushing the vertical baffle (4) and the quick-change wedge block (3) to move in the slide block (5) and adjusting the distance between the quick-change wedge block (3) and the roller (2).
8. A biaxial tension test device with variable load ratio as claimed in claim 7, characterized in that the initial positions of the quick-change wedges (3) and the vertical baffles (4) are determined by the screwing depth of the positioning bolt (6), and the inclined surfaces of the quick-change wedges are adjusted to be just contacted with the roller (2) by the positioning bolt (6).
9. A biaxial tension test apparatus with variable load ratio as claimed in claim 1, wherein the high speed camera (12) is located right below the biaxial tension specimen (11) and is equipped with two shadowless lamps (13).
10. The biaxial tension test device with the variable load ratio as claimed in claim 1, wherein the bracket (9) is disposed right below four grooves of the rail-type cross base (8).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911251601.9A CN111044363A (en) | 2019-12-09 | 2019-12-09 | Biaxial tension experimental device with variable load ratio |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911251601.9A CN111044363A (en) | 2019-12-09 | 2019-12-09 | Biaxial tension experimental device with variable load ratio |
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| CN111044363A true CN111044363A (en) | 2020-04-21 |
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| CN201911251601.9A Pending CN111044363A (en) | 2019-12-09 | 2019-12-09 | Biaxial tension experimental device with variable load ratio |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112945747A (en) * | 2021-02-03 | 2021-06-11 | 武汉大学 | Three-dimensional pressure loading device suitable for nanoindentation test system |
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2019
- 2019-12-09 CN CN201911251601.9A patent/CN111044363A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101907538A (en) * | 2010-07-29 | 2010-12-08 | 哈尔滨工业大学 | Mechanical biaxial tension tester with variable proportion loading |
| CN204903286U (en) * | 2015-07-31 | 2015-12-23 | 浙江吉利汽车研究院有限公司 | Multidirectional tensile test fixture of material |
| CN205192828U (en) * | 2015-12-07 | 2016-04-27 | 中国石油天然气集团公司 | Supplementary metal material mechanical testing's instrument |
| CN106908319A (en) * | 2017-03-27 | 2017-06-30 | 山东大学 | A kind of two-way cross tensile test device |
| CN207396191U (en) * | 2017-11-16 | 2018-05-22 | 南通耀华建设工程质量检测有限公司 | A kind of composited aluminum and plastic decking bending strength test frame |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112945747A (en) * | 2021-02-03 | 2021-06-11 | 武汉大学 | Three-dimensional pressure loading device suitable for nanoindentation test system |
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Application publication date: 20200421 |
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| RJ01 | Rejection of invention patent application after publication |