An experimental method for rock split Hopkinson tension bar testing

Abstract

The present invention discloses an experimental method for rock separation Hopkinson pull rod test. Before the test begins, a glue injection positioning device is used to fix the two ends of a cylindrical sample to the corresponding impact rods by gluing. The glue injection positioning device includes an impact rod fixing assembly for fixing the impact rod and a sample fixing assembly for fixing the sample. The impact rod fixing assembly and the sample fixing assembly are connected by a positioning cursor assembly. After the test, a melt glue cleaning device is used to remove the glue on the end of the impact rod. The melt glue cleaning device includes a cleaning box and a storage box. A sample through hole is connected between the left and right walls of the cleaning box. A heating resistor wire is provided on the inner wall of the cleaning box, and two telescopic rods are symmetrically provided on the top of the cleaning box. A scraper is fixed at the bottom of each telescopic rod. The present invention can solve the technical difficulties of glue injection positioning and melt glue cleaning of rock samples in the process of separation Hopkinson pull rod experiment in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of rock material dynamics experiments, and in particular to an experimental method for rock separation-type Hopkinson pull-bar testing. Background Art

[0002] The split-Hopkinson bar test system is currently the most effective testing equipment for the high-strain-rate direct tensile mechanical behavior of rock materials. In particular, the use of the split-Hopkinson bar test device to study the dynamic tensile mechanical properties of brittle rock materials under impact tensile loads plays an important role in the design of rock engineering structures and stability assessment, and is also a difficult problem that urgently needs to be solved in the rock mechanics and engineering fields.

[0003] The connection method between the rock sample and the incident rod and the transmission rod is the primary problem to be solved in the split-Hopkinson tension bar experiment. The main connection methods for the sample are threaded connection, hanging connection and bonding. Considering that rock is a brittle material and it is difficult to process it into the same size and specifications as metal materials, bonding becomes a more reliable connection method. The conventional test procedure for the rock split-Hopkinson tension bar experiment using bonding currently includes three steps: (1) Experimental preparation stage, it is necessary to bond the cylindrical rock sample to the incident rod and the transmission rod with high-strength glue; (2) Experimental implementation stage, the impact tensile test is completed by the split-Hopkinson tension bar; (3) Experimental end stage, it is necessary to quickly and thoroughly clean the ends of the incident rod and the transmission rod to carry out the next set of experiments. The entire rock split-Hopkinson bar test process has the following difficult problems that need to be solved urgently: (1) How to inject glue between the two end faces of the specimen and the incident rod and transmission rod and ensure the consistency of the injection thickness on both sides to ensure the effectiveness of the test; (2) After the split-Hopkinson bar experiment is completed, how to quickly and effectively remove the residual glue stuck to the end faces of the incident rod and transmission rod in order to carry out the next set of tests. Summary of the Invention

[0004] In response to the above-mentioned problems, the present invention aims to provide an experimental method for rock split-Hopkinson bar testing to solve the technical difficulties of glue injection positioning and melt cleaning of rock samples during the split-Hopkinson bar test in the prior art.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0006] An experimental method for rock split-Hopkinson pull-bar testing, characterized by comprising the following steps:

[0007] S1: Use the glue injection positioning device to glue the two ends of the cylindrical specimen to the corresponding impact rods. The glue injection thickness at both ends of the specimen is the same.

[0008] S2: After the glue is allowed to solidify for 24 hours, the sample is subjected to a split-Hopkinson bar impact tensile test;

[0009] S3: After the impact tensile test is completed, the impact rod with the broken specimen is placed in the melt glue cleaning device to remove the glue on the end of the impact rod.

[0010] Furthermore, the glue injection positioning device includes an impact rod fixing assembly for fixing the impact rod and a sample fixing assembly for fixing the sample, and the impact rod fixing assembly and the sample fixing assembly are connected via a positioning cursor assembly;

[0011] The positioning cursor assembly includes a connecting buckle and a cursor, the connecting buckle is rotatably connected to the cursor, and the connecting buckle is connected to the impact rod fixing assembly, the cursor is connected to the sample fixing assembly, and the outer side wall of the sample fixing assembly is provided with a scale mark for marking the cursor position.

[0012] Furthermore, the impact rod fixing assembly includes an impact rod fixing sleeve and a positioning rod, the bottom of the impact rod fixing sleeve is provided with a slot along the axial direction, and the bottom of the two side edges of the slot are fixed with a fixing plate, the two fixing plates are arranged in parallel, and the two fixing plates are symmetrically provided with limiting through holes, and the two limiting through holes are connected by a locking bolt;

[0013] The positioning rod is an L-shaped structure, and the inner side wall of the long side of the positioning rod is an arc-shaped structure that matches the specimen. The end of the positioning rod away from the short side contacts but is not connected to the end of the impact rod fixing sleeve;

[0014] A plurality of limiting protrusions for connecting with the connecting buckle are evenly provided on the outer side wall of the end of the impact rod fixing sleeve away from the positioning rod.

[0015] Furthermore, both ends of the connecting buckle are open structures, and a plurality of positioning grooves matching the limiting protrusions are provided on the inner side wall of one end of the connecting buckle close to the impact rod fixing sleeve, and each of the positioning grooves is connected to a gradually tightening limiting groove along the circumference of the connecting buckle;

[0016] A rotation groove is provided on the inner side wall of the end of the connecting buckle away from the impact rod fixing sleeve, and a rotating ring matching the rotation groove is fixed on the end of the cursor close to the connecting buckle. A plurality of ball grooves are provided on the side of the rotating ring close to the cursor, and a ball is provided in each ball groove, and the ball is tangent to the side wall of the rotation groove;

[0017] An internal thread connected to the sample fixing assembly is provided on the inner side wall of the cursor.

[0018] Furthermore, the sample fixing assembly includes a sample fixing sleeve, an outer wall of the sample fixing sleeve at one end close to the cursor is provided with an external thread matching the internal thread on the inner wall of the cursor, and a plurality of mounting blocks are symmetrically provided on the outer wall of the sample fixing sleeve at one end away from the cursor, each mounting block is provided with a mounting groove on a side facing the inside of the fixing sleeve, a sample fixing mechanism is installed in the mounting groove, and the scale mark is located between the external thread and the mounting block;

[0019] The sample fixing sleeve is further provided with a glue injection hole, and the glue injection hole is located between the scale mark and the mounting block.

[0020] Furthermore, the sample fixing mechanism includes a roller mounting frame, a roller is mounted inside the roller mounting frame, and an automatic locking member is provided on the roller; a positioning plate is fixed to the outside of the roller mounting frame, a support sleeve is fixed to a side of the positioning plate away from the roller mounting frame, a return spring is sleeved inside the support sleeve, one end of the return spring is fixedly connected to the inner side wall of the corresponding mounting groove, and the other end of the return spring is fixedly connected to the positioning plate;

[0021] An infrared detector is also provided on the inner side wall of the sample fixing sleeve.

[0022] Furthermore, the melt cleaning device includes a cleaning box and a storage box, the cleaning box is located on the top of the storage box, and the bottom of the cleaning box is connected to the top of the storage box;

[0023] A sample through hole is provided between the left and right walls of the cleaning box, a heating resistance wire is provided on the inner wall of the cleaning box, and two telescopic rods are symmetrically provided on the top of the cleaning box, and a scraper is fixed at the bottom of each telescopic rod.

[0024] Furthermore, the cleaning box includes two symmetrical half-boxes, the two half-boxes are detachably connected via magnets, and a first observation window is provided on the top of each half-box;

[0025] Second observation windows are provided on the left and right walls of the storage box.

[0026] Furthermore, two L-shaped card plates are symmetrically provided on the top of the storage box, and L-shaped card slots matching the L-shaped card plates are provided on the bottoms of the two half box bodies.

[0027] The beneficial effects of the present invention are as follows: compared with the prior art, the improvement of the present invention is that:

[0028] 1. The experimental method for rock separation Hopkinson tension bar testing disclosed in the present invention uses a glue injection positioning device to glue the two ends of the cylindrical sample to the corresponding impact rod before the test. The glue injection thickness at both ends of the sample is the same, which can improve the accuracy of the sample test and also support the sample while waiting for the glue to solidify. After the test, the impact rod with the broken sample is placed in a melt glue cleaning device, which can quickly remove the glue on the end of the impact rod, thereby facilitating the reuse of the impact rod. The entire experimental process is simple to operate and has high experimental accuracy.

[0029] 2. The glue injection positioning device in the present invention can fix the impact rod through the impact rod fixing assembly, and the relative position between the impact rod and the impact rod fixing sleeve can be fixed under the mutual cooperation of the positioning rod and the impact rod fixing sleeve. After the impact rod fixing assembly, the positioning cursor assembly and the sample fixing assembly are connected, the position of the impact rod relative to the positioning cursor assembly is also fixed, and can move with the movement of the positioning cursor assembly, so as to accurately adjust the position of the end of the impact rod close to the test; the sample fixing assembly can fix the sample, and when the sample just blocks the infrared detector on the inner wall of the sample fixing sleeve, the roller is locked, and the position of the end of the sample close to the impact rod can be fixed. The thickness of the glue injection can be adjusted by adjusting the position of the impact rod close to one end of the sample through the positioning cursor assembly. The scale mark can accurately reflect the position of the impact rod. Therefore, it is only necessary to adjust the positions of the two impact rods (incident rod and transmission rod) to the same scale mark to ensure that the glue injection thickness at both ends of the sample is the same. The operation is simple and the accuracy is high. The glue injection thickness accuracy can be accurate to 0.01mm.

[0030] 3. The molten glue cleaning device of the present invention first heats and melts the glue on the end of the impact rod through a heating resistor wire, and then uses a telescopic rod to drive a scraper to remove the glue on the end of the impact rod, which effectively solves the technical difficulties of molten glue cleaning in the prior art. The cleaning box adopts a detachable connection method of two half box bodies through magnets, which is convenient for cleaning and maintenance of the inside of the cleaning box. The detachable connection between the cleaning box and the storage box also facilitates cleaning the inside of the storage box. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the external structure of the glue injection positioning device of the present invention.

[0032] Figure 2 This is a cross-sectional view of the internal structure of the glue injection positioning device of the present invention.

[0033] Figure 3 This is a schematic diagram of the external structure of the impact rod fixing sleeve of the present invention.

[0034] Figure 4 It is a side sectional view of the impact rod fixing sleeve of the present invention.

[0035] Figure 5 This is a schematic diagram of the positioning rod structure of the present invention.

[0036] Figure 6 This is a schematic diagram of the external structure of the positioning cursor assembly of the present invention.

[0037] Figure 7 This is an exploded view of the positioning cursor assembly of the present invention.

[0038] Figure 8 Schematic diagram of the external structure of the sample fixing assembly of the present invention.

[0039] Figure 9 This is an exploded view of the sample fixing assembly of the present invention.

[0040] Figure 10 Schematic diagram of the sample fixing mechanism structure of the present invention.

[0041] Figure 11 This is a schematic diagram of the external structure of the melt adhesive cleaning device of the present invention.

[0042] Figure 12 This is a cross-sectional view of the internal structure of the melt adhesive cleaning device of the present invention.

[0043] Figure 13 It is a schematic structural diagram of the cleaning box of the present invention.

[0044] Figure 14 It is a structural schematic diagram of the storage box of the present invention.

[0045] Among them: 1-impact rod, 2-connecting buckle, 3-cursor, 301-internal thread, 4-scale mark, 5-impact rod fixing sleeve, 6-positioning rod, 7-slot, 8-fixing plate, 9-limiting through hole, 10-locking bolt, 11-limiting protrusion, 12-positioning groove, 13-limiting groove, 14-rotation groove, 15-rotating ring, 16-ball groove, 17-ball, 18-sample fixing sleeve, 1801-external thread, 19-installation Mounting block, 20-mounting slot, 21-glue injection hole, 22-roller mounting frame, 23-roller, 24-positioning plate, 25-support sleeve, 26-reset spring, 27-cleaning box, 2701-half box body, 2702-magnet, 28-storage box, 29-sample through hole, 30-heating resistance wire, 31-telescopic rod, 32-scraper, 33-first observation window, 34-second observation window, 35-L-shaped card plate, 36-L-shaped card slot. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0047] An experimental method for rock split-Hopkinson tension bar testing comprises the following steps:

[0048] S1: Use a glue injection positioning device to glue the two ends of the cylindrical specimen to the corresponding impact rod 1. The glue injection thickness at both ends of the specimen is the same. In the rock split-Hopkinson tension bar test, there are two impact rods 1, one as the incident rod and the other as the transmission rod. The two ends of the specimen are glued to the incident rod and the transmission rod respectively. Two glue injection positioning devices can be used to glue the two ends of the impact rod 1 separately.

[0049] S2: After the sample is allowed to stand for 24 hours and the glue solidifies, a split-Hopkinson tension rod impact tensile test is performed on the sample. The specific impact tensile test process adopts the existing impact tensile test method and is not described in detail in this application.

[0050] S3: After the impact tensile test is completed, the impact rod 1 with the broken sample is placed in the melt glue cleaning device to remove the glue on the end of the impact rod 1. During this process, the ends of the two impact rods 1 (the incident rod and the transmission rod) connected to the sample are placed in the melt glue cleaning device at the same time for glue cleaning.

[0051] Specifically, the glue injection positioning device is as shown in the attached Figure 1-10 As shown, it includes an impact rod fixing assembly for fixing the impact rod 1 and a sample fixing assembly for fixing the sample, and the impact rod fixing assembly and the sample fixing assembly are connected via a positioning cursor assembly;

[0052] The positioning cursor assembly includes a connecting buckle 2 and a cursor 3, both of which are barrel-shaped structures with openings at both ends. The connecting buckle 2 is rotatably connected to the cursor 3, and the connecting buckle 2 is connected to the impact rod fixing assembly, and the cursor 3 is connected to the sample fixing assembly. A scale mark 4 for marking the position of the cursor 3 is provided on the outer wall of the sample fixing assembly.

[0053] More specifically, the impact rod fixing assembly includes an impact rod fixing sleeve 5 and a positioning rod 6. The impact rod fixing sleeve 5 is made of a flexible material, and a slot 7 is provided at the bottom of the impact rod fixing sleeve 5 along the axial direction. A fixing plate 8 is fixed to the bottom of both side edges of the slot 7. The two fixing plates 8 are arranged in parallel, and the two fixing plates 8 are symmetrically provided with limiting through holes 9. The two limiting through holes 9 are connected by a locking bolt 10.

[0054] The positioning rod 6 is an L-shaped structure, and the inner side wall of the long side of the positioning rod 6 is an arc structure matching the sample, and the end of the positioning rod 6 away from the short side is in contact with the end of the impact rod fixing sleeve 5 but not connected; when in use, the end of the long side of the positioning rod 6 away from the short side is in contact with the end of the impact rod fixing sleeve 5, and the short side of the positioning rod 6 is pressed against the end of the impact rod 1, and the inner side of the long side of the positioning rod 6 is fitted with the impact rod 1, and the locking bolt 10 is used to lock and fix the two limiting through holes 9, so that the relative position between the impact rod 1 and the impact rod fixing sleeve 5 can be fixed, so that the impact rod 1 and the impact rod fixing sleeve 5 are fixed together, and the positioning rod 6 can be removed from the impact rod 1 at this time.

[0055] A plurality of limiting protrusions 11 for connecting with the connecting buckle 2 are evenly provided on the outer side wall of the end of the impact rod fixing sleeve 5 away from the positioning rod 6 .

[0056] Furthermore, both ends of the connecting buckle 2 are open structures, and a plurality of positioning grooves 12 matching the limiting protrusions 11 are provided on the inner wall of one end of the connecting buckle 2 close to the impact rod fixing sleeve 5, and each of the positioning grooves 12 is connected to a gradually tightening limiting groove 13 along the circumference of the connecting buckle 2; during installation, the limiting protrusions 11 on the impact rod fixing sleeve 5 with the specimen fixed are aligned with the corresponding positioning grooves 12, and then the connecting buckle 2 is rotated so that the limiting protrusions 11 enter the gradually tightening limiting grooves 13, thereby achieving the effect of fixing the connecting buckle 2 and the impact rod fixing sleeve 5.

[0057] A rotation groove 14 is defined on the inner sidewall of the end of the connecting clip 2 facing away from the impact rod fixing sleeve 5. A rotating ring 15 is fixed to the end of the cursor 3 near the connecting clip 2, matching the rotation groove 14. The rotating ring 15 has multiple ball grooves 16 on the side of the rotating ring 15 near the cursor 3. Each ball groove 16 contains a ball 17, which is tangential to the sidewall of the rotation groove 14. The balls 17 enable the rotating ring 15 and the rotating groove 14 to rotate relative to each other but do not translate, remaining aligned on the same axis. The inner sidewall of the cursor 3 is provided with internal threads 301 that connect to the specimen fixing assembly. During use, the cursor 3 is threadedly connected to the specimen fixing assembly. When the cursor 3 rotates, the connecting clip 2 and the impact rod fixing sleeve 5 connected to the connecting clip 2 do not rotate, but can move axially with the cursor 3, thereby adjusting the position of the impact rod 1. The entire positioning cursor assembly is made entirely of transparent material.

[0058] The sample fixing assembly includes a sample fixing sleeve 18, and an external thread 1801 matching the internal thread on the inner wall of the cursor 3 is provided on the outer side wall of the sample fixing sleeve 18 close to the cursor 3. The cursor 3 and the sample fixing sleeve 18 are detachably connected through the internal thread on the cursor 3 and the external thread 1801 on the sample fixing sleeve 18. At the same time, the length of the threaded connection of the cursor 3 on the sample fixing sleeve 18 is adjustable, so that the end position of the impact rod 1 is adjustable.

[0059] A plurality of mounting blocks 19 are symmetrically provided on the outer side wall of the sample fixing sleeve 18 away from the cursor 3. Each mounting block 19 has a mounting groove 20 on the side facing the inside of the fixing sleeve 18. The sample fixing mechanism is installed in the mounting groove 20. The scale mark 4 is located between the external thread 1801 and the mounting block 19.

[0060] The sample fixing sleeve 18 also has a glue injection hole 21 located between the scale mark 4 and the mounting block 19. An infrared detector (not shown) is also provided on the inner sidewall of the sample fixing sleeve 18. The sample is inserted into the sample fixing sleeve 18 from the end of the sample fixing sleeve 18 where the mounting block 19 is located. When the sample just blocks the infrared rays, the sample fixing mechanism locks, securing the sample. Since the infrared detector is fixed, the position of the end of the sample inserted into the sample fixing sleeve 18 is also fixed. The position of the end of the impact rod 1 can be adjusted by rotating the cursor 3 on the sample fixing sleeve 18. The scale mark 4 accurately reflects the position of the end of the impact rod 1. The distance between the end of the impact rod 1 and the end of the sample represents the glue injection thickness. It should be noted that the infrared detector on the inner sidewall of the sample fixing sleeve 18 is equipped with an infrared receiver and controller to detect the relative position of the sample and the infrared detector. This technology is prior art and will not be described in detail in this application.

[0061] The sample fixing mechanism includes a roller mounting bracket 22, which is of a U-shaped structure, and the opening of the U-shaped structure faces the center of the sample fixing sleeve 18. A roller 23 is installed inside the roller mounting bracket 22, and an automatic locking member is provided on the roller 23, which can be locked by a controller. A positioning disk 24 is fixedly arranged outside the roller mounting bracket 22, and a support sleeve 25 is fixedly arranged on one side of the positioning disk 24 away from the roller mounting bracket 22. A return spring 26 is sleeved inside the support sleeve 25. One end of the return spring 26 is fixedly connected to the inner side wall of the corresponding mounting groove 20, and the other end of the return spring 26 is fixedly connected to the positioning disk 24. When the return spring 26 is in a balanced state, a part of the roller 23 is located in the sample fixing sleeve 18 outside the mounting block 19. When a sample is inserted into the sample fixing sleeve 18, it will push the roller 23 to rotate and simultaneously compress the return spring 26. When the sample just blocks the infrared ray, the controller is used to lock and fix the roller 23. Under the extrusion of the return spring 26 and the friction of the roller 23, the sample is clamped and fixed, playing a role in controlling the position of the sample fixing.

[0062] Further, the glue cleaning device described in step S3 is as shown in the appendix Figure 11-14 and includes a cleaning box 27 and a storage box 28. The cleaning box 27 is located on the top of the storage box 28, and the bottom of the cleaning box 27 is communicated with the top of the storage box 28. The cleaning box 27 is used to remove the glue on the end of the impact rod 1, and the storage box 28 is used to collect the samples and glue residues dropping from the impact rod 1 during the glue removal process.

[0063] A sample through hole 29 is communicated between the left side wall and the right side wall of the cleaning box 27. A heating resistance wire 30 is arranged on the inner side wall of the cleaning box 27. The heating resistance wire 30 can heat the glue at the end of the impact rod 1 to 100 - 200 °C to melt the glue. Two telescopic rods 31 are symmetrically arranged on the top of the cleaning box 27. A scraper 32 is fixedly arranged at the bottom of each telescopic rod 31. The glue can be scraped by driving the scraper 32 to move up and down through the telescopic rod 31. A pressure sensor (not shown in the figure) can also be installed on the scraper 32. If the pressure is too high to peel off the glue, the heating resistance wire 30 is continuously used for heating until the pressure is satisfied.

[0064] The cleaning box 27 includes two symmetrical half boxes 2701. The two half boxes 2701 are detachably connected by a magnet 2702. A first observation window 33 is opened on the top of each half box 2701. The two telescopic rods 31 are respectively arranged on the two half boxes 2701. The position of the impact rod 1 in the cleaning box 27 and the glue removal situation can be observed through the first observation window 33.

[0065] Second observation windows 34 are provided on both the left and right walls of the storage box 28 , and the second observation windows 34 are used to observe the situation inside the storage box 28 .

[0066] Two L-shaped card plates 35 are symmetrically provided on the top of the storage box 28, and L-shaped card slots 36 matching the L-shaped card plates 35 are provided on the bottom of the two half box bodies 2701. After the two half box bodies 2701 are fixed together by magnets 2702, the two L-shaped card plates 35 are inserted into the corresponding L-shaped card slots 36, so that the two half box bodies 2701 are detachably connected, and the cleaning box 27 and the storage box 28 are also detachably connected, which is convenient for cleaning and maintenance of the cleaning box 27 and the storage box 28.

[0067] The working principle of the glue injection positioning device in the present invention is: when in use, the end of the sample is fixed to the impact rod 1 through the glue injection positioning device. Specifically, the end of the long side of the positioning rod 6 away from the short side is in contact with the end of the impact rod fixing sleeve 5, and the short side of the positioning rod 6 is pressed against the end of the impact rod 1, and the inner side of the long side of the positioning rod 6 is in contact with the impact rod 1. The locking bolt 10 is used to lock and fix the two limiting through holes 9, so that the relative position between the impact rod 1 and the impact rod fixing sleeve 5 can be fixed, so that the impact rod 1 and the impact rod fixing sleeve 5 are fixed together. At this time, the positioning rod 6 can be removed from the impact rod 1.

[0068] Align the limiting protrusions 11 on the impact rod fixing sleeve 5 that fixes the sample with the corresponding positioning grooves 12, and then rotate the connecting buckle 2 to make the limiting protrusions 11 enter the gradually tightening limiting grooves 13, so as to achieve the fixing effect between the connecting buckle 2 and the impact rod fixing sleeve 5.

[0069] Insert the sample into the sample fixing sleeve 18, and the sample will push the roller 23 to rotate and squeeze the reset spring 26 at the same time. When the sample just blocks the infrared rays, use the controller to lock and fix the roller 23. Under the squeezing action of the reset spring 26 and the friction force of the roller 23, the sample is clamped and fixed, which plays the role of fixing and controlling the position of the sample.

[0070] Rotate the cursor 3 to adjust the position of the cursor 3 on the sample fixing sleeve 18. When the cursor 3 rotates, the connecting buckle 2 and the impact rod fixing sleeve 5 connected to the connecting buckle 2 will not rotate, but can move axially along with the cursor 3, thereby adjusting the position of the impact rod 1. The position of the end of the impact rod 1 can be accurately reflected by the scale mark 4. The distance between the end of the impact rod 1 and the end of the sample is the glue injection thickness. Finally, glue is injected through the glue injection hole 21.

[0071] The working principle of the melt adhesive cleaning device in the present invention is as follows: after the tensile test of the sample is completed, two impact rods 1 (incident rod and transmission rod) with broken samples attached are placed in the melt adhesive cleaning device, the ends of the impact rods 1 are located below the scraper 32, the heating resistor 30 is energized, and the adhesive at the ends of the impact rods 1 is heated to 100-200°C to melt the adhesive; then the telescopic rod 31 is controlled to drive the scraper 32 to move up and down to scrape off the adhesive.

[0072] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. An experimental method for rock split Hopkinson tension bar testing, characterized in that: The following steps are included: S1: Use a glue injection positioning device to glue and fix the two ends of the cylindrical specimen to the corresponding impact rod (1) respectively, and the glue injection thickness at both ends of the specimen is the same; S2: After the glue is allowed to solidify for 24 hours, the sample is subjected to a split-Hopkinson rod impact tensile test; S3: After the impact tensile test is completed, the impact rod (1) with the broken sample attached is placed in a melt-adhesive cleaning device to remove the adhesive on the end of the impact rod (1); The glue injection positioning device comprises an impact rod fixing assembly for fixing the impact rod (1) and a sample fixing assembly for fixing the sample, wherein the impact rod fixing assembly and the sample fixing assembly are connected via a positioning cursor assembly; The positioning cursor assembly comprises a connecting buckle (2) and a cursor (3), wherein the connecting buckle (2) is rotatably connected to the cursor (3), and the connecting buckle (2) is connected to the impact rod fixing assembly, and the cursor (3) is connected to the sample fixing assembly, and a scale mark (4) for marking the position of the cursor (3) is provided on the outer side wall of the sample fixing assembly; The impact rod fixing assembly comprises an impact rod fixing sleeve (5) and a positioning rod (6), the bottom of the impact rod fixing sleeve (5) is provided with a slot (7) along the axial direction, and fixing plates (8) are fixedly provided at the bottom of both side edges of the slot (7), the two fixing plates (8) are arranged in parallel, and the two fixing plates (8) are symmetrically provided with limiting through holes (9), and the two limiting through holes (9) are connected by a locking bolt (10); The positioning rod (6) is an L-shaped structure, and the inner side wall of the long side of the positioning rod (6) is an arc-shaped structure matching the sample, and the end of the positioning rod (6) away from the short side is in contact with the end of the impact rod fixing sleeve (5) but not connected; A plurality of limiting protrusions (11) for connecting with the connecting buckle (2) are evenly arranged on the outer side wall of one end of the impact rod fixing sleeve (5) away from the positioning rod (6).

2. The experimental method for rock separation Hopkinson tension bar test according to claim 1, characterized in that: Both ends of the connecting buckle (2) are open structures, and a plurality of positioning grooves (12) matching the limiting protrusion (11) are provided on the inner side wall of one end of the connecting buckle (2) close to the impact rod fixing sleeve (5), and each of the positioning grooves (12) is connected to a gradually tightening limiting groove (13) along the circumference of the connecting buckle (2); A rotation groove (14) is provided on the inner side wall of one end of the connection buckle (2) away from the impact rod fixing sleeve (5); a rotation ring (15) matching the rotation groove (14) is fixedly provided on one end of the cursor (3) close to the connection buckle (2); a plurality of ball grooves (16) are provided on one side of the rotation ring (15) close to the cursor (3); a ball (17) is provided in each ball groove (16); and the ball (17) is tangent to the side wall of the rotation groove (14); An inner wall of the cursor (3) is provided with an internal thread (301) connected to the sample fixing assembly.

3. The experimental method for rock separation Hopkinson pull bar test according to claim 2, characterized in that: The sample fixing assembly comprises a sample fixing sleeve (18), an outer wall of one end of the sample fixing sleeve (18) close to the cursor (3) is provided with an external thread (1801) matching the internal thread on the inner wall of the cursor (3), and a plurality of mounting blocks (19) are symmetrically provided on the outer wall of one end of the sample fixing sleeve (18) away from the cursor (3), each mounting block (19) is provided with a mounting groove (20) on a side facing the inside of the fixing sleeve (18), a sample fixing mechanism is installed in the mounting groove (20), and the scale mark (4) is located between the external thread (1801) and the mounting block (19); The sample fixing sleeve (18) is also provided with a glue injection hole (21), and the glue injection hole (21) is located between the scale mark (4) and the mounting block (19).

4. The experimental method for rock separation Hopkinson tension bar test according to claim 3, characterized in that: The sample fixing mechanism comprises a roller mounting frame (22), a roller (23) is mounted inside the roller mounting frame (22), and an automatic locking member is provided on the roller (23); a positioning plate (24) is fixedly provided outside the roller mounting frame (22), a supporting sleeve (25) is fixedly provided on a side of the positioning plate (24) away from the roller mounting frame (22), a return spring (26) is sleeved inside the supporting sleeve (25), one end of the return spring (26) is fixedly connected to the inner side wall of the corresponding mounting groove (20), and the other end of the return spring (26) is fixedly connected to the positioning plate (24); An infrared detector is also provided on the inner side wall of the sample fixing sleeve (18).

5. The experimental method for rock separation Hopkinson tension bar test according to claim 1, characterized in that: The melt cleaning device comprises a cleaning box (27) and a storage box (28), wherein the cleaning box (27) is located on the top of the storage box (28), and the bottom of the cleaning box (27) is connected to the top of the storage box (28); A sample through hole (29) is provided between the left and right walls of the cleaning box (27), a heating resistor (30) is provided on the inner wall of the cleaning box (27), and two telescopic rods (31) are symmetrically provided on the top of the cleaning box (27), and a scraper (32) is fixedly provided at the bottom of each telescopic rod (31).

6. The experimental method for rock separation Hopkinson tension bar test according to claim 5, characterized in that: The cleaning box (27) comprises two symmetrical half box bodies (2701), the two half box bodies (2701) are detachably connected via magnets (2702), and a first observation window (33) is provided on the top of each half box body (2701); Second observation windows (34) are provided on both the left and right walls of the storage box (28).

7. The experimental method for rock separation Hopkinson tension bar test according to claim 6, characterized in that: Two L-shaped card plates (35) are symmetrically arranged on the top of the storage box (28), and L-shaped card slots (36) matching the L-shaped card plates (35) are arranged on the bottoms of the two half box bodies (2701).

Images