Hopkinson bar concrete material double-sided shear test device and its use method

Abstract

The present invention provides a Hopkinson bar concrete material double-sided shear test device and a method for using the same, comprising a transmission bar, a hollow sleeve fixed to the transmission bar is sleeved on the front end of the transmission bar, a solid truncated cone is fixedly connected to the front end of the hollow sleeve, an incident bar is arranged at the front end of the solid truncated cone, a double-sided shear test piece is sandwiched between the rear end of the incident bar and the solid truncated cone, and an absorption bar is fixed on the rear end of the transmission bar. The present invention has a simple structure, a reasonable design, greatly enlarges the cross-sectional size of the component, can realize a double-sided shear test of concrete materials on the Hopkinson bar, can more effectively reflect the actual dynamic shear performance of concrete, has high stability and strong usability, improves test efficiency, and is innovative.

Description

Technical Field

[0001] The invention relates to a Hopkinson bar concrete material double-sided shear test device and a use method thereof. Background Art

[0002] At present, the split Hopkinson pressure bar (SHPB) technology is considered to be one of the most effective methods to measure the dynamic properties of solid materials. The strain rate of prefabricated concrete structures under seismic loads is within the testable range of the Hopkinson bar. Considering the symmetry and uniformity of the double-sided shear specimens, the Hopkinson bar is used to carry out the double-sided shear test of prefabricated composite beams.

[0003] Due to the large size of coarse aggregates contained in concrete materials and the inhomogeneity of the material, the measurement results of small specimens cannot effectively reflect their macroscopic statistical laws. In order to ensure the validity of the test data, the method of increasing the specimen size is generally used to reduce the test error. Therefore, the cross-sectional size of the compression bar of the SHPB test device shows an increasing trend. At present, the diameter of the compression bar of the Hopkinson compression bar is generally 50~100mm. When conducting a double-sided shear test on concrete, due to the limitation of the cross-sectional size of the compression bar, the size of the double-sided shear specimen is too small, which is not conducive to the actual in-plane dynamic shear performance.

[0004] Some earlier test devices achieve the same test effect by changing the cross-sectional size of the input rod (variable cross-sectional compression rod). However, increasing the cross-sectional size of the compression rod will also increase the lateral inertia of the stress wave in the compression rod and increase its diffusion effect, making the friction effect between the specimen and the end face of the compression rod more obvious.

[0005] Meyer (Adiabatic shear strength of low alloy steel under compression, Application of shock waves and high strain rate phenomena in the field of alloys, Meyer ed., New York, 1986: 647-657.) used axial impact compression to achieve shear loading of hat-shaped structure specimens, and measured the impact shear failure strength of the material at a local position through the design of self-shearing of the specimen. The specimen structure required for this method is complex and difficult to prepare, especially for anisotropic materials such as composite materials. The complexity of the specimen itself also makes the test and data processing more complicated and difficult.

[0006] Based on the above dynamic shear device for metal materials, the existing SHPB test device has a small cross-sectional size, which limits the size of the concrete specimen. The double-sided shear test of concrete materials is not effective and cannot more effectively reflect the macroscopic dynamic performance of the concrete shear surface. Summary of the invention

[0007] The present invention improves the above-mentioned problem, that is, the technical problem to be solved by the present invention is to provide a Hopkinson bar concrete material double-sided shear test device and a use method thereof, which is simple to disassemble and convenient to use.

[0008] The specific implementation scheme of the present invention is to provide a Hopkinson bar concrete material double-sided shear test device and a use method thereof, comprising a transmission rod, a hollow sleeve fixed to the transmission rod is sleeved on the front end of the transmission rod, a solid truncated cone is fixedly connected to the front end of the hollow sleeve, an incident rod is arranged at the front end of the solid truncated cone, and a double-sided shear test piece is sandwiched between the rear end of the incident rod and the solid truncated cone.

[0009] Furthermore, the solid truncated cone includes an upper circular surface and a lower circular surface, the diameter of the upper circular surface is smaller than that of the lower circular surface, the upper circular surface of the solid truncated cone is fixedly connected to the hollow sleeve, the hollow sleeve is plugged into the transmission rod, and an absorption rod is also fixed to the rear end of the transmission rod.

[0010] Furthermore, the solid cone and the hollow sleeve are integrated.

[0011] Furthermore, the inner diameter of the hollow sleeve is larger than the outer diameter of the transmission rod, and the end of the transmission rod is wrapped with raw tape for filling the gap between the hollow sleeve and the transmission rod. After the hollow sleeve is connected to the transmission rod, a strong adhesive tape is wrapped around the connection between the transmission rod and the sleeve for fixing the transmission rod and the hollow sleeve.

[0012] Furthermore, the center lines of the incident rod, the double-sided shear specimen, the solid frustum, the sleeve, the transmission rod, and the absorption rod are located on the same horizontal line.

[0013] Furthermore, the solid cone and the hollow sleeve are both made of Q235 steel.

[0014] Furthermore, a bullet and a launching device for driving the bullet to be launched are provided at the front end of the incident rod.

[0015] Furthermore, a damper for consuming kinetic energy is provided at the rear end of the absorption rod.

[0016] Furthermore, the shooting rod and the transmission rod are provided with strain gauges, and the strain gauges are electrically connected to the data processing system respectively.

[0017] Furthermore, a method for using a Hopkinson rod concrete material double-sided shear test device includes the following steps: (1) first, adjusting the horizontality and coaxiality of the incident rod and the transmission rod to ensure that the center line of the incident rod and the center line of the transmission rod remain coaxial and horizontal; (2) after wrapping the end of the transmission rod with raw tape, insert the transmission rod with one end wrapped with the raw tape into the hollow sleeve and fix it; (3) wrapping a strong adhesive tape on the outside of the connection between the hollow sleeve and the transmission rod for further reinforcement; (4) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (5) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (6) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (7) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (8) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (9) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (10) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (11) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (12) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (13) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (14) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (15) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (16) wrapping the double-sided shear test device with the raw tape wrapped on the hollow sleeve and the transmission rod; (17) wrapping the double-sided shear test device with the raw tape wrapped The two ends of the specimen are clamped between the incident rod and the lower circular surface of the solid cone and fixed, and the position of the double-sided shear specimen is adjusted so that the incident rod, double-sided shear specimen, solid cone, hollow sleeve and the central axis of the transmission rod are at the same horizontal position; (5) After the inspection is completed, the launch device is driven to fire the bullet and start the test; (6) The computer data processing system (virtual oscilloscope) collects, records and stores the relevant time domain dynamic strain signals; (7) After the impact is completed, the test data collection and recording are completed, and the specimen is removed.

[0018] Furthermore, the incident rod and the transmission rod are provided with strain gauges, and the strain gauges are electrically connected to the data processing system.

[0019] Compared with the prior art, the present invention has the following beneficial effects: the device has reasonable design, simple structure, convenient assembly and disassembly, low cost, does not affect the validity of the data, has high stability and strong usability, and is particularly suitable for the study of dynamic shear properties of composite materials such as concrete, and is practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the connection between the hollow sleeve and the transmission rod according to an embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of the structure of a double-sided shear specimen according to an embodiment of the present invention.

[0023] In the figure: 1-incident rod, 2-transmission rod, 3-double-sided shear specimen, 31-loading end, 32-support end, 4-solid truncated cone, 41-upper circular surface, 42-lower circular surface, 5-absorption rod, 6-bullet, 7-damper, 8-launching device, 9-data processing system, 10-hollow sleeve, 11-strain gauge. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example: Figures 1 to 3As shown, in this embodiment, a Hopkinson bar concrete material double-sided shear test device and a method of using the same are provided, including a transmission rod 2, a hollow sleeve 10 fixed to the transmission rod is sleeved on the front end of the transmission rod 2, a solid frustum 4 is fixedly connected to the front end of the hollow sleeve 10, an incident rod 1 is provided at the front end of the solid frustum 4, and a double-sided shear specimen 3 is sandwiched between the rear end of the incident rod 1 and the solid frustum 4.

[0026] In this embodiment, the double-sided shear specimen 3 includes a loading end 31 and two symmetrical supporting ends 32, and the connection portion between the loading end 31 and the supporting end is a rectangular shear area.

[0027] In this embodiment, the solid truncated cone 4 includes an upper circular surface 41 and a lower circular surface 42, the diameter of the upper circular surface is smaller than that of the lower circular surface, the upper circular surface of the solid truncated cone is fixedly connected to the hollow sleeve 10, the hollow sleeve 10 is plugged into the transmission rod 2, and an absorption rod 5 is coaxially fixed on the rear end of the transmission rod.

[0028] In this embodiment, the solid cone 4 and the hollow sleeve 10 may also be integrated.

[0029] In this embodiment, the inner diameter of the hollow sleeve 10 is larger than the outer diameter of the transmission rod 2, and the inner diameter of the hollow sleeve can be 2 mm larger than the outer diameter of the transmission rod. The end of the transmission rod is wrapped with raw tape, and the end of the transmission rod wrapped with the raw tape is inserted into the hollow sleeve. The raw tape can fill the gap between the inside of the hollow sleeve and the transmission rod.

[0030] In this embodiment, after the hollow sleeve 10 is connected to the transmission rod 2, a strong adhesive tape is wrapped around the outer connection between the transmission rod and the hollow sleeve to fix the transmission rod and the hollow sleeve, so as to ensure the fixing strength.

[0031] In this embodiment, the center lines of the incident rod, the double-sided shear test piece, the solid frustum, the sleeve, the transmission rod and the absorption rod are located on the same horizontal line.

[0032] In this embodiment, the solid cone and the hollow sleeve are both made of Q235 steel and are durable.

[0033] In this embodiment, a horizontally arranged bullet 6 and a launching device 8 for driving the bullet to be launched are provided at the front end of the incident rod 1 .

[0034] In this embodiment, a damper 7 for consuming motion energy is provided at the rear end of the absorption rod 5 .

[0035] In this embodiment, strain gauges 11 are provided on the incident rod 1 and the transmission rod 2. The strain gauges on the incident rod and the transmission rod are electrically connected to a data processing system 9 respectively. The data processing system 9 can be a virtual oscilloscope installed on a computer.

[0036] In this embodiment, when used, first, adjust the horizontality and coaxiality of the incident rod 1 and the transmission rod 2 to ensure that the two are horizontal and coaxial, then wrap the raw tape around the end of the transmission rod 2, insert the transmission rod 2 into the hollow sleeve 10 and fix it, and then wrap the strong tape around the connection position of the hollow sleeve 10 and the transmission rod 2 for further fixation, then, clamp the double-sided shear specimen 3 between the incident rod and the solid truncated cone and fix it, and adjust the position of the double-sided shear specimen so that the incident rod, the double-sided shear specimen, the solid truncated cone, the hollow sleeve and the central axis of the transmission rod are at the same horizontal position, after the inspection is completed, drive the launch device to launch the bullet, and the data processing system (virtual oscilloscope) on the computer collects, records and stores the time domain dynamic strain signal, and finally, after the impact test is completed, remove the specimen. The present invention has a simple structure, reasonable design, simple operation, easy disassembly, does not affect the impact test of other materials by the original device pressure rod, has low cost, improves test efficiency, does not affect the validity of data, and is particularly suitable for the dynamic shear property research of composite materials such as concrete.

[0037] Unless otherwise stated, any technical solution disclosed in the present invention disclosed above, if it discloses a numerical range, then the disclosed numerical range is a preferred numerical range, and any technician in the field should understand that the preferred numerical range is only a numerical value with a more obvious technical effect or representative value among many implementable numerical values. Since there are too many numerical values ​​to be exhaustive, the present invention discloses some numerical values ​​to illustrate the technical solution of the present invention, and the numerical values ​​listed above should not constitute a limitation on the scope of protection of the present invention.

[0038] At the same time, if the above-mentioned invention discloses or involves components or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (for example, connected by bolts or screws), and can also be understood as: a non-detachable fixed connection (for example, riveting, welding). Of course, the mutual fixed connection can also be replaced by an integrated structure (for example, manufactured by one-piece molding using a casting process) (except when it is obviously impossible to use an integrated molding process).

[0039] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in the present invention include states or shapes that are approximate, similar, or close to them.

[0040] Any component provided by the present invention may be assembled from a plurality of separate components, or may be a separate component manufactured by an integral forming process.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A Hopkinson bar concrete material double-sided shear test device, characterized in that: It comprises a transmission rod, a hollow sleeve fixed to the transmission rod is sleeved on the front end of the transmission rod, a solid truncated cone is fixedly connected to the front end of the hollow sleeve, an incident rod is arranged at the front end of the solid truncated cone, and a double-sided shear test piece is sandwiched between the rear end of the incident rod and the solid truncated cone; The solid truncated cone includes an upper circular surface and a lower circular surface, wherein the diameter of the upper circular surface is smaller than that of the lower circular surface, the upper circular surface of the solid truncated cone is fixedly connected to the hollow sleeve, the hollow sleeve is plugged and matched with the transmission rod, and an absorption rod is also fixed to the rear end of the transmission rod; The inner diameter of the hollow sleeve is larger than the outer diameter of the transmission rod, and a raw tape for filling the gap between the hollow sleeve and the transmission rod is wound on the end of the transmission rod. After the hollow sleeve is connected to the transmission rod, a strong adhesive tape for fixing the transmission rod and the hollow sleeve is wound at the connection between the transmission rod and the sleeve; The center lines of the incident rod, double-sided shear specimen, solid frustum, sleeve, transmission rod and absorption rod are located on the same horizontal line.

2. A Hopkinson bar concrete material double-sided shear test device according to claim 1, characterized in that: The solid frustum and the hollow sleeve are integrated.

3. A Hopkinson bar concrete material double-sided shear test device according to claim 2, characterized in that: The solid truncated cone and the hollow sleeve are both made of Q235 steel.

4. A Hopkinson bar concrete material double-sided shear test device according to claim 3, characterized in that: A bullet and a launching device for driving the bullet to be launched are arranged at the front end of the incident rod.

5. A Hopkinson bar concrete material double-sided shear test device according to claim 4, characterized in that: A damper for consuming motion energy is arranged at the rear end of the absorption rod.

6. A Hopkinson bar concrete material double-sided shear test device according to claim 5, characterized in that: The shooting rod and the transmission rod are provided with strain gauges, which are electrically connected to a data processing system.

7. A method for using the Hopkinson bar concrete material double-sided shear test device as claimed in claim 6, characterized in that: The method comprises the following steps: (1) first, adjusting the horizontality and coaxiality of the incident rod and the transmission rod to ensure that the center line of the incident rod and the center line of the transmission rod remain coaxial and horizontal; (2) after wrapping the end of the transmission rod with raw tape, insert the transmission rod with one end wrapped with raw tape into the hollow sleeve for fixing; (3) wrapping the outer part of the connection between the hollow sleeve and the transmission rod with strong tape for further reinforcement; (4) clamping the two ends of the double-sided shear specimen between the incident rod and the lower circular surface of the solid truncated cone and fixing them, adjusting the position of the double-sided shear specimen so that the incident rod, the double-sided shear specimen, the solid truncated cone, the hollow sleeve and the central axis of the transmission rod are located at the same horizontal position; (5) after the inspection is completed, driving the launch device, launching the bullet, and starting the test; (6) the virtual oscilloscope in the computer data processing system collects, records, and stores the relevant time domain dynamic strain signal; (7) after the impact is completed, the test data collection and recording is completed, and the specimen is removed.

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