Clamping device for dynamic tensile test of metal material

Abstract

The invention relates to the technical field of metal material dynamic mechanical property tests, and provides a metal material dynamic tensile test clamping device which comprises a clamping section, an extension section and a test piece fixing section which are sequentially connected along a straight line, an anti-skid structure is arranged on the surface of the clamping section and is used for being clamped and fixed on a clamping mechanism on the dynamic tensile testing machine; the extension section can be matched with the groove of the clamping mechanism, the test piece fixing section is provided with a connecting part, and the connecting part can be connected with one end of the tensile test piece; the clamping device is connected with the tensile test piece, so that the total length of the tensile test piece is effectively prolonged, machining of the test piece and effective clamping on a testing machine are facilitated, the test pieces of different specifications can be conveniently replaced by releasing connection between the connecting part and the tensile test piece, the test preparation process is simplified through the design of the device, and the test efficiency is improved. The manufacturing cost of the test piece is reduced and the working efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of dynamic tensile testing of metal materials, and in particular to a clamping device for dynamic tensile testing of metal materials. Background Art

[0002] In daily use, traditional metal structures are sometimes subjected to impact loads in addition to static loads. For example, during the service life of an aircraft, its surface skin structure may be affected by impact loads such as bird strikes and emergency crashes. The nose and wing structures of an aircraft are the focus of attention when impacted by foreign objects such as flying birds and hail, and the lower structure of the aircraft body must be designed to resist crashes in order to enhance its crashworthiness. In coal mine tunnels, metal support structures are sometimes subjected to the impact of surrounding rocks under the impact of rock bursts, so it is sometimes necessary to explore their impact resistance. When the structure is under impact load, the mechanical performance of the material must consider the influence of the strain rate effect compared to quasi-static loading, that is, as the loading strain rate continues to increase, the material usually shows a certain strain rate sensitivity. According to previous research results, the strength limit and failure strain of metal materials such as titanium alloys and alloy steels will change significantly when the strain rate increases, but the rate sensitivity of aluminum alloys is relatively weak or even non-existent. Therefore, in order to accurately carry out impact resistance design and analysis of metal structures, it is necessary to use experimental methods to obtain the dynamic mechanical performance parameters of the material.

[0003] Typically, the strain rate is 10 -5 / s to 10³ / s is a medium-low strain rate state, and the states outside the two ends of this range are quasi-static and high strain rate states respectively. It should be noted that in different strain rate ranges, suitable test equipment must be used to carry out mechanical property tests. For example, the quasi-static range generally uses conventional static testing machines, the medium-low strain rate range usually uses high-speed hydraulic servo testing machines, and the high strain rate range generally uses Hopkinson bar testing devices. In comparison, the test methods for the dynamic mechanical properties of materials in the medium-low strain rate range are not as mature as the test methods under quasi-static and high strain rates. This is mainly reflected in the relatively small number of medium-low strain rate dynamic tensile tests on materials based on high-speed hydraulic servo testing machines, and further consensus needs to be reached on key test parameter testing and test data processing.

[0004] Compared with metal material specimens subjected to quasi-static and static tensile tests, metal material specimens subjected to dynamic tensile tests using high-speed hydraulic servo testing machines require a very long clamping section to meet the design requirements of the specification and the operational requirements of the dynamic tensile test. As a result, a large amount of material is wasted and the test cost is increased. In addition, thin tensile specimens will also face the problem of difficulty in clamping the dynamic clamping device on the testing machine and slippage, which seriously affects the accuracy of the dynamic tensile test results of metal materials. Summary of the invention

[0005] The invention provides a clamping device for dynamic tensile testing of metal materials, which is used to solve the problems in the prior art that tensile test pieces are not clamped tightly and the specifications of dynamic and static metal material test pieces are not uniform, resulting in increased manufacturing costs.

[0006] The present invention provides a clamping device for a dynamic tensile test of a metal material, comprising a clamping section, an extension section and a specimen fixing section which are connected in sequence along a straight line; the surface of the clamping section is provided with an anti-slip structure for being clamped and fixed on a clamping mechanism on a dynamic tensile testing machine; the extension section can be matched with a groove of the clamping mechanism, and the specimen fixing section is provided with a connecting portion, which can be connected to one end of a tensile specimen.

[0007] According to the metal material dynamic tensile test clamping device provided by the present invention, the connecting part includes a mounting groove and a cover plate, the mounting groove is opened on one side of the specimen fixing section, the mounting groove can be snap-fitted with one end of the tensile specimen for placing and locking the tensile specimen; the cover plate is connected to one side of the specimen fixing section for closing the opening of the mounting groove.

[0008] According to the metal material dynamic tensile test clamping device provided by the present invention, a protrusion is provided on the side of the cover plate facing the mounting groove, and the protrusion is adapted to the mounting groove and is used to extend into the mounting groove to clamp the tensile specimen.

[0009] According to the metal material dynamic tensile test clamping device provided by the present invention, the cover plate is detachably connected to the specimen fixing section.

[0010] The metal material dynamic tensile test clamping device provided by the present invention also includes a gasket, which is adapted to the mounting groove and is used to be placed between the protrusion and the tensile specimen, and is used to clamp the tensile specimen by squeezing the protrusion.

[0011] According to the clamping device for dynamic tensile testing of metal materials provided by the present invention, at least one gasket is provided, and the thickness m of the gasket is 1-2 mm.

[0012] According to the metal material dynamic tensile test clamping device provided by the present invention, the clamping section, the extension section and the specimen fixing section are all plate-like structures, and the thickness of the specimen fixing section is greater than the thickness of the extension section, and the surface of the extension section and the surface of the specimen fixing section are connected by an arc surface transition at the connection point.

[0013] According to the clamping device for dynamic tensile testing of metal materials provided by the present invention, the width and thickness of the clamping section and the extension section are the same, and the total length c of the clamping section and the extension section is 250-350 mm.

[0014] According to the clamping device for dynamic tensile testing of metal materials provided by the present invention, the length a of the clamping section is 80-100 mm, the width g is 35-45 mm, and the thickness b is 3-5 mm.

[0015] According to the clamping device for dynamic tensile testing of metal materials provided by the present invention, the length k of the installation groove is 40-80 mm, the width j is 10-60 mm, and the depth f is 3-8 mm.

[0016] The present invention provides a clamping device for a dynamic tensile test of a metal material, comprising a clamping section, an extension section and a specimen fixing section which are sequentially connected along a straight line; the surface of the clamping section is provided with an anti-slip structure for being clamped and fixed on a clamping mechanism on a dynamic tensile test machine; the extension section can be matched with a groove of the clamping mechanism, and the specimen fixing section is provided with a connecting portion, which can be connected to one end of the tensile specimen; the present invention provides an anti-slip structure for the clamping section, so that it is convenient to be effectively clamped by the clamping mechanism on the dynamic tensile test machine, reduce slippage, ensure that the clamping section will not slip out of the dynamic clamping mechanism under high stress, and ensure To ensure the accuracy of the test results; the extension section is placed in the groove of the clamping mechanism during the test to avoid shaking and reduce errors caused by deflection or uneven force. In addition, the existence of the extension section makes up for the problem of insufficient length of the tensile specimen. By connecting the clamping device to the tensile specimen, the "total length" of the tensile specimen is effectively extended, which is convenient for the processing of the specimen and the effective clamping on the testing machine. At the same time, by releasing the connection between the connecting part and the tensile specimen, specimens of different specifications can be easily replaced. The design of the device simplifies the test preparation process, reduces material processing costs, and improves work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of the structure of a metal material dynamic tensile test clamping device connected to a tensile test piece provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of a clamping device for a dynamic tensile test of a metal material provided by an embodiment of the present invention; Figure 3 A schematic structural diagram of a cover plate of a clamping device for a dynamic tensile test of a metal material provided by an embodiment of the present invention; Figure 4 A schematic structural diagram of a gasket of a clamping device for a dynamic tensile test of a metal material provided by an embodiment of the present invention; Figure 5 A side view of a clamping device for a dynamic tensile test of a metal material provided by an embodiment of the present invention; Figure 6 A top view of a clamping device for a dynamic tensile test of a metal material provided by an embodiment of the present invention; Figure 7 A side view of a gasket provided in accordance with an embodiment of the present invention.

[0019] Reference numerals: 1. Clamping section; 11. Anti-slip structure; 2. Extension section; 3. Specimen fixing section; 31. Mounting slot; 32. Bolt hole; 4. Cover plate; 41. Protrusion; 42. Through hole; 5. Gasket; 6. Tensile specimen; 7. Bolt. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Combine the following Figure 1-Figure 5 The invention describes a clamping device for dynamic tensile testing of metal materials.

[0022] An embodiment of the present invention provides a clamping device for a dynamic tensile test of a metal material, comprising a clamping section 1, an extension section 2 and a specimen fixing section 3 connected in sequence along a straight line; the surface of the clamping section 1 is provided with an anti-slip structure 11, which is used to be clamped and fixed on a clamping mechanism on a dynamic tensile testing machine; the extension section 2 can be adapted to the groove of the clamping mechanism, and the specimen fixing section 3 is provided with a connecting portion, which can be connected to one end of a tensile specimen 6.

[0023] It can be seen from the above scheme that the present invention provides a clamping device for dynamic tensile testing of metal materials. When working, the specimen fixing section 3 is connected to the tensile specimen 6. By setting an anti-slip structure 11 on the clamping section 1, it is convenient to be effectively clamped by the clamping mechanism on the dynamic tensile testing machine, reducing slippage, ensuring that the clamping section 1 will not slip out of the dynamic clamping mechanism under high stress, and ensuring the accuracy of the test results; the extension section 2 is placed in the groove of the clamping mechanism during the test to avoid shaking and reduce errors caused by deflection or uneven force. In addition, due to the existence of the extension section 2, the problem of insufficient length of the tensile specimen 6 is compensated. By connecting the clamping device to the tensile specimen 6, the "total length" of the tensile specimen 6 is effectively extended, which is convenient for the processing of the specimen and the effective clamping on the testing machine. At the same time, by releasing the connection between the connecting part and the tensile specimen 6, specimens of different specifications can be easily replaced. The design of the device simplifies the test preparation process, reduces material processing costs, and improves work efficiency.

[0024] It should be noted that the dynamic tensile testing machine is a product in the prior art. Its structure and principle are not the focus of this article and will not be described in detail here.

[0025] The above-mentioned anti-slip structure 11 can be a structure formed by roughening the surface of the clamping section 1 through a laser scoring process. For example, it can be parallel or staggered teeth processed on the surface of the clamping section 1, or the surface can be processed into a cross-net texture, or a plurality of small protrusions are formed on the surface.

[0026] like Figure 1-Figure 2 As shown, in a further embodiment, the connecting portion includes a mounting groove 31 and a cover plate 4. The mounting groove 31 is opened on one side of the specimen fixing section 3. The mounting groove 31 can be snap-fitted with one end of the tensile specimen 6 for placing and locking the tensile specimen 6; the cover plate 4 is connected to one side of the specimen fixing section 3 for closing the opening of the mounting groove 31.

[0027] With such arrangement, the mounting groove 31 is snap-fitted with one end of the tensile specimen 6 to ensure that the tensile specimen 6 will not easily slide out or shift during the test, thereby providing a stable clamping force for the tensile specimen 6 and maintaining a good fixing effect even under high stress conditions. The opening of the mounting groove 31 is closed by the cover plate 4 to reliably fix the end of the tensile specimen 6 in the mounting groove 31, thereby clamping the tensile specimen 6 and preventing the tensile specimen 6 from shaking or suddenly falling off in the mounting groove 31, thereby affecting the test effect. The present invention achieves reliable fixation of one end of the tensile specimen 6 and the clamping device through the combination of the mounting groove 31 and the cover plate 4. The installation and fixing process is simple and reliable, which can ensure that the position of the tensile specimen 6 remains fixed during the test, thereby providing a more stable loading condition and improving the accuracy of the test data.

[0028] In this embodiment, the clamping device is made of aluminum alloy as a whole, which has the advantages of light weight and high strength. For example, the clamping section 1, the extension section 2, the specimen fixing section 3 and the cover plate 4 are all made of 7 series aviation aluminum alloy blanks through lathe milling, which avoids the adverse effect of steel materials on the test results due to their own heavy weight. At the same time, the high strength can avoid the damage to the clamping device caused by the impact of the dynamic stretching process, thereby effectively ensuring the data accuracy of the dynamic tensile test of metal materials and reducing the processing cost of the specimens.

[0029] Preferably, the cover plate 4 is detachably connected to the specimen fixing section 3; such a configuration facilitates installation and disassembly, improves the test efficiency, and can achieve rapid and reliable fixation of the tensile specimen 6, especially when the specimen needs to be replaced frequently.

[0030] In some specific embodiments, a plurality of bolt holes 32 are evenly distributed around the opening of the mounting groove 31, and a plurality of through holes 42 are correspondingly provided on the cover plate 4. The number of through holes 42 and the bolt holes 32 are the same and the positions correspond one to one. The cover plate 4 is connected to the specimen fixing section 3 by passing bolts 7 through the through holes 42 and the bolt holes 32.

[0031] like Figure 3 As shown, further, a protrusion 41 is provided on the side of the cover plate 4 facing the mounting groove 31, and the protrusion 41 is adapted to the mounting groove 31, and is used to extend into the mounting groove 31 to clamp the tensile specimen 6, that is, the shape contour of the protrusion 41 is consistent with that of the mounting groove 31; in this way, since the protrusion 41 is adapted to the mounting groove 31, the reliability of the connection between the cover plate 4 and the specimen fixing section 3 can be improved through the concave-convex cooperation, and the protrusion 41 can act on the tensile specimen 6 to squeeze and clamp it, thereby ensuring that the tensile specimen 6 can be reliably fixed in the mounting groove 31.

[0032] like Figure 4 As shown, in this embodiment, a gasket 5 is also included, which is adapted to the mounting groove 31, and is used to be placed between the protrusion 41 and the tensile test piece 6, and is used to clamp the tensile test piece 6 by squeezing the protrusion 41. In this way, according to the thickness of the tensile test piece 6, the gasket 5 of different thicknesses can be used in combination to adjust the position of the tensile test piece 6, ensure that the axis of the clamping device and the axis of the tensile test piece 6 are consistent, and avoid eccentric loading. In particular, when the thickness of the tensile test piece 6 is small and is insufficient to contact the protrusion 41 after being installed in the mounting groove 31, the gasket 5 can be placed to clamp the tensile test piece 6 in the mounting groove 31.

[0033] like Figure 7 As shown, in some embodiments, the thickness m of the gasket 5 is 1-2 mm.

[0034] like Figure 1-Figure 2 As shown, the clamping section 1, the extension section 2 and the specimen fixing section 3 are all plate-like structures, and the thickness of the specimen fixing section 3 is greater than the thickness of the extension section 2. The surface of the extension section 2 and the surface of the specimen fixing section 3 are connected at the connection point through an arc transition; the mounting groove 31 is a rectangular groove, and a notch is provided on the side of the rectangular groove away from the extension section 2, for allowing the tensile specimen 6 except the fixed end to pass through.

[0035] In this way, the arc surface transition design can make the transmission of force from the extension section 2 to the specimen fixing section 3 smoother, and can eliminate the stress concentration phenomenon easily caused by the traditional right-angle or sharp-angle connection method. In particular, during the loading process, the connection may become a weak point, increasing the risk of fracture, and the arc surface transition can effectively disperse the stress, so that the force can be transmitted more evenly, reducing the stress concentration phenomenon at the connection and reducing the weight.

[0036] like Figure 5-Figure 6 As shown, the width and thickness of the clamping section 1 and the extension section 2 are the same, and the total length c of the clamping section 1 and the extension section 2 is 250-350 mm.

[0037] Optionally, the length a of the clamping section 1 is 80-100 mm, the width g is 35-45 mm, and the thickness b is 3-5 mm; the length d of the specimen fixing section 3 is 90-110 mm, the height e of the specimen fixing section 3 is 10-15 mm, and the width h of the specimen fixing section 3 is 40-80 mm; the length k of the mounting groove 31 is 40-80 mm, the width j is 10-60 mm, and the depth f is 3-8 mm In some embodiments, the length a of the clamping section 1 is 80 mm, the thickness b of the clamping section 1 is 4 mm, the total length c of the clamping section 1 and the extension section 2 is 280 mm, the length d of the specimen fixing section 3 is 90 mm, the height e of the specimen fixing section 3 is 12 mm, and the depth f of the mounting groove 31 in the specimen fixing section 3 is 4.5 mm.

[0038] In some embodiments, the width g of the clamping section 1 is 40 mm, the width h of the specimen fixing section 3 is 60 mm, the length k of the mounting groove 31 in the specimen fixing section 3 is 60 mm, and the width j of the mounting groove 31 is 40 mm.

[0039] The installation process of a metal material dynamic tensile test clamping device provided in this embodiment is as follows: one end of a tensile test piece 6 of the metal material is placed in the installation groove 31 of the test piece clamping device, the protrusion 41 provided on the aluminum alloy cover plate 4 extends into the installation groove 31 and clamps the tensile test piece 6 together with the gasket 5 (whether to use it is selected according to the thickness requirement), and a high-strength steel bolt 7 is used to pass through the through hole 42 and the bolt hole 32 to connect the test piece fixing section 3 and the cover plate 4, the clamping section 1 is fixed on the clamping mechanism of the dynamic tensile testing machine, and the extension section 2 is placed in the groove of the clamping mechanism to avoid shaking.

[0040] The present invention provides an anti-slip structure 11 for the clamping section 1, so as to facilitate effective clamping by the clamping mechanism on the dynamic tensile testing machine, reduce slippage, ensure that the clamping section 1 will not slip out of the dynamic clamping mechanism under high stress, and ensure the accuracy of the test result; the extension section 2 is placed in the groove of the clamping mechanism during the test to avoid shaking and reduce errors caused by deflection or uneven force. In addition, due to the existence of the extension section 2, the problem of insufficient length of the tensile specimen 6 is compensated. By connecting the clamping device to the tensile specimen 6, the "total length" of the tensile specimen 6 is effectively extended, which is convenient for the processing of the specimen and the effective clamping on the testing machine. By releasing the connection between the connecting part and the tensile specimen 6, specimens of different specifications can be easily replaced. The design of the device simplifies the test preparation process, reduces material processing costs, and improves work efficiency. In addition, the entire metal material dynamic tensile test clamping device is made of a 7 series aviation aluminum alloy blank through lathe milling, which has the effects of light weight and high strength, avoiding the adverse effects of steel materials on the test results due to their own heavy weight. At the same time, its own high strength can avoid damage to the clamping device caused by the impact of the dynamic tensile process, thereby effectively ensuring the data accuracy of the dynamic tensile test of metal materials and reducing the processing cost of the specimens.

[0041] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0042] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of the different embodiments or modes, without contradiction.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A clamping device for dynamic tensile testing of metal materials, characterized in that: The invention comprises a clamping section (1), an extension section (2) and a specimen fixing section (3) which are connected in sequence along a straight line; the surface of the clamping section (1) is provided with an anti-slip structure (11) for being clamped and fixed on a clamping mechanism on a dynamic tensile testing machine; the extension section (2) is capable of matching with a groove of the clamping mechanism; the specimen fixing section (3) is provided with a connecting portion, and the connecting portion is capable of connecting with one end of a tensile specimen (6).

2. The metal material dynamic tensile test clamping device according to claim 1, characterized in that: The connecting portion comprises a mounting groove (31) and a cover plate (4); the mounting groove (31) is provided on one side of the specimen fixing section (3); the mounting groove (31) can be snap-fitted with one end of the tensile specimen (6) for placing and locking the tensile specimen (6); the cover plate (4) is connected to one side of the specimen fixing section (3) for closing the opening of the mounting groove (31).

3. The metal material dynamic tensile test clamping device according to claim 2, characterized in that: A protrusion (41) is provided on one side of the cover plate (4) facing the mounting groove (31); the protrusion (41) is adapted to fit the mounting groove (31) and is used to extend into the mounting groove (31) to clamp the tensile test piece (6).

4. The metal material dynamic tensile test clamping device according to claim 2, characterized in that: The cover plate (4) is detachably connected to the specimen fixing section (3).

5. The metal material dynamic tensile test clamping device according to claim 3, characterized in that: It also includes a gasket (5), which is adapted to the mounting groove (31), is used to be placed between the protrusion (41) and the tensile test piece (6), and is used to clamp the tensile test piece (6) by squeezing the protrusion (41).

6. The metal material dynamic tensile test clamping device according to claim 5, characterized in that: At least one gasket (5) is provided, and the thickness m of the gasket (5) is 1-2 mm.

7. The metal material dynamic tensile test clamping device according to claim 1, characterized in that: The clamping section (1), the extension section (2) and the specimen fixing section (3) are all plate-like structures, the thickness of the specimen fixing section (3) is greater than the thickness of the extension section (2), and the surface of the extension section (2) and the surface of the specimen fixing section (3) are connected at the connection point through a curved surface transition.

8. The metal material dynamic tensile test clamping device according to claim 7, characterized in that: The width and thickness of the clamping section (1) and the extension section (2) are the same, and the total length c of the clamping section (1) and the extension section (2) is 250-350 mm.

9. The metal material dynamic tensile test clamping device according to claim 7, characterized in that: The length a of the clamping section (1) is 80-100 mm, the width g is 35-45 mm, and the thickness b is 3-5 mm.

10. The metal material dynamic tensile test clamping device according to claim 2, characterized in that: The length k of the installation groove (31) is 40-80 mm, the width j is 10-60 mm, and the depth f is 3-8 mm.

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