CN112816348A - Multi-connected microscopic NPR anchor rod Hopkinson tensile test device and test method - Google Patents
Multi-connected microscopic NPR anchor rod Hopkinson tensile test device and test method Download PDFInfo
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- CN112816348A CN112816348A CN202011614696.9A CN202011614696A CN112816348A CN 112816348 A CN112816348 A CN 112816348A CN 202011614696 A CN202011614696 A CN 202011614696A CN 112816348 A CN112816348 A CN 112816348A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/30—Investigating strength properties of solid materials by application of mechanical stress by applying a single impulsive force, e.g. by falling weight
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/02—Details
- G01N3/04—Chucks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/06—Indicating or recording means; Sensing means
- G01N2203/067—Parameter measured for estimating the property
- G01N2203/0676—Force, weight, load, energy, speed or acceleration
Abstract
The invention provides a multi-connected microscopic NPR anchor rod Hopkinson tensile test device and a test method, wherein the test device comprises a support workbench, a launching tube and a buffer device are arranged on the support workbench, the launching tube is used for launching a striking rod, and the test device further comprises an input rod, a movable connecting part, a fixed connecting part and an anchor rod sample; the input rod and the launching tube are coaxially arranged, and the impact rod impacts the input rod along the axial direction; the movable connecting part is arranged between the input rod and the buffer device and is arranged on the supporting workbench in an axial sliding manner; the fixed connecting part is fixed on the supporting workbench; one end of the anchor rod sample is fixed on the fixed connecting part, and the other end of the anchor rod sample is fixed on the movable connecting part; the anchor rod sample is parallel to the input rod, the input rod is arranged between the launching tube and the movable connecting part, and the movable connecting part is positioned between the fixed connecting part and the buffer device. The test device realizes the dynamic mechanical property test of a plurality of microscopic NPR anchor rods under the condition of high strain rate.
Description
Technical Field
The invention belongs to the technical field of anchor rod mechanical property research, and particularly relates to a multi-connected microscopic NPR anchor rod Hopkinson tensile test device and a test method.
Background
Bolting has been widely used in mine bolting as an effective means of bolting. With the continuous improvement of the mining depth and safety requirements, particularly the more frequent rock burst of deep wells and coal mines, the anchor rod manufactured based on the traditional Poisson's ratio material cannot meet the requirements of supporting and controlling deep soft rock large deformation disasters. In order to solve the problem that the constitutive relation of the rock mechanics in mining of mines cannot be used for the double challenges that the established engineering design and the traditional anchor bolt support cannot meet the disaster control requirement under the condition of large impact deformation easily, the novel energy absorption anchor bolt support material is developed by flood academicians based on the constant-resistance large-deformation material impact-prevention control concept, is called a micro NPR anchor bolt new material (NPR for short), and has more excellent mechanical properties than the traditional material.
The mechanical property test method can be divided into four types of loading, namely static, quasi-static, medium strain rate and high strain rate loading according to different loading conditions, namely the range of the strain rate. A large number of indoor and outdoor static tensile tests, drop hammer impact tests and field tests exist in mechanical property research experiments of the microcosmic NPR anchor rod, but the microcosmic NPR anchor rod mainly belongs to three types of static, quasi-static and medium strain rates, and dynamic mechanical property research of the microcosmic NPR anchor rod under the high strain rate is lacked. Unlike static and quasi-static, structural and inertial effects will primarily affect the dynamic response characteristics of the material under impact loading, i.e., it is not known whether the microscopic NPR bolt can exhibit a negative poisson's ratio effect caused by structural deformation under dynamic impact. That is, at present, no test device for the dynamic mechanical characteristics of the multi-connected microscopic NPR anchor rod under the high strain rate exists.
Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
Disclosure of Invention
The invention aims to provide a multi-connected microscopic NPR anchor rod Hopkinson tensile test device and a test method, and at least solves the problem that no test device for the dynamic mechanical property of a multi-connected microscopic NPR anchor rod under a high strain rate exists at present.
In order to achieve the above purpose, the invention provides the following technical scheme:
many microscopic NPR stock hopkinson tensile test device that ally oneself with, testing arrangement includes the supporting workbench, be equipped with launching tube and buffer on the supporting workbench, the launching tube is used for launching the impact bar, experimental apparatus still includes:
the input rod is arranged on the supporting workbench in a sliding mode, the input rod is coaxially and adjacently arranged with the launching tube, and the impact rod impacts the input rod along the axial direction of the input rod and is used for enabling the input rod to move along the axial direction;
the movable connecting part is arranged between the input rod and the buffer device, and is arranged on the supporting workbench in an axial sliding manner along the input rod;
the fixed connecting part is fixed on the supporting workbench;
the device comprises an anchor rod sample, a movable connecting part and an input rod, wherein one end of the anchor rod sample is fixed on the fixed connecting part, the other end of the anchor rod sample is fixed on the movable connecting part, and one end of the input rod, which is far away from a launching tube, is abutted against the movable connecting part and is used for transmitting the impact force of an impact rod to the anchor rod sample;
the anchor rod sample and the input rod are arranged in an overlapped mode in the axial direction of the input rod, the axis of the anchor rod sample is parallel to the axis of the input rod, the input rod is arranged between the launching tube and the movable connecting portion, and the movable connecting portion is located between the fixed connecting portion and the buffer device;
and the force measuring element is arranged on the movable connecting part and is used for detecting the impact acting force of the input rod on the movable connecting part.
As described above, the multi-connected microscopic NPR bolt hopkinson tensile test device preferably includes:
the test piece fixing seat is provided with an avoidance space and a second guide hole, the avoidance space is used for the input rod to pass through, and the second guide hole is used for the anchor rod test piece to pass through;
and one end of the anchor rod sample penetrating through the second guide hole is fixedly connected with the second fastener, and the second fastener is in blocking fit with the sample fixing seat.
As above-mentioned many online microcosmic NPR stock hopkinson tensile test device, preferably, the vertical cross-section of sample fixing base is the U type, and the space at U type middle part is used for forming dodges the space, all is provided with the second guiding hole on the both sides of U type.
As above-mentioned many online microcosmic NPR stock hopkinson tensile test device, preferably, the hole of dodging has been seted up on the sample fixing base, the hole of dodging is used for forming dodge the space, dodge the hole with the coaxial setting of input rod, the internal diameter more than or equal to of dodging the hole the external diameter of input rod.
The multi-connected microscopic NPR bolt hopkinson tensile test device as described above, preferably, the movable connection portion includes:
the impact guide plate is provided with the force measuring element and a first guide hole, the first guide hole is used for one end of the anchor rod sample to pass through, and the first guide hole and the second guide hole which are penetrated by the same anchor rod sample are coaxially arranged;
the first fastening piece is fixedly connected with one end, penetrating through the first guide hole, of the anchoring sample, and the second fastening piece is in blocking fit with the impact guide plate.
In the multi-connected microscopic NPR anchor rod hopkinson tensile test device, preferably, the second fastener is a nut, and the second fastener is in threaded connection with one end of the anchor rod sample; the first fastener is a nut and is in threaded connection with one end of the anchor rod sample.
The multi-connected microscopic NPR anchor rod hopkinson tensile test device preferably comprises an impact bearing plate arranged on the impact guide plate, the impact bearing plate is arranged on the impact guide plate and faces one side of the input rod, the impact bearing plate and the input rod are coaxially arranged, the impact bearing plate is used for bearing the impact acting force of the input rod, and the side force element is arranged on the impact bearing plate;
preferably, the impact bearing plate is disc-shaped and is connected with the impact guide plate into a whole through a screw;
preferably, the load cell is a pressure sensor.
In the multi-connected microscopic NPR anchor rod hopkinson tensile test device, preferably, a slide rail is arranged on the support workbench, the slide rail is arranged along the axial direction of the input rod, a slide groove is arranged at the bottom of the impact guide plate, and the slide rail is slidably connected in the slide groove;
preferably, the cross sections of the sliding rail and the sliding groove are in a shape of a Chinese character 'ao' or a dovetail groove.
As above-mentioned many online microcosmic NPR stock hopkinson tensile test device, preferably, the test device still includes a plurality of input rod mounts that set up side by side, be equipped with the third guiding hole on the input rod mount, the input rod passes a plurality ofly the third guiding hole, the third guiding hole is used for supporting the input rod, and makes the input rod is along axial direction guiding motion.
The application also provides a multi-connected microscopic NPR anchor rod Hopkinson tensile test method, the test method uses any one of the multi-connected microscopic NPR anchor rod Hopkinson tensile test device, and the test method comprises the following steps:
step S1, ensuring the safety of the placement position and the surrounding environment of the test device and ensuring the safe and reliable operation;
step S2, grease is applied to the contact parts of the components in the test device for lubricating the contact parts so as to eliminate the friction effect;
step S3, fixing the input rod fixing frame, the sample fixing seat, the impact guide plate and the absorption device on a supporting workbench;
step S4, fixing the input rod in the third guide hole of the input rod fixing frame;
step S5, firstly inserting the anchor rod sample into the second guide hole of the sample fixing seat and the first guide hole of the impact guide plate, then correspondingly screwing the first connecting nut and the second connecting nut on the first end and the second end of the anchor rod sample respectively, enabling the first connecting nut and the impact guide plate to form first stop matching, enabling the second connecting nut and the sample fixing seat to form second stop matching, and finally enabling one end part of the input rod to abut against the impact bearing disc of the impact guide plate;
step S6, ensuring the connection of each connection part of the test device to be firm;
and step S7, starting the transmitting tube to perform the test, and recording the test data.
Compared with the closest prior art, the technical scheme provided by the invention has the following excellent effects:
according to the invention, two ends of the anchor rod sample are respectively connected with the sample fixing seat and the impact guide plate, and the impact guide plate moves along the axial direction of the input rod under the impact action of the input rod on the impact guide plate, so that the dynamic mechanical property test of a plurality of microcosmic NPR anchor rods under the condition of high strain rate is realized.
According to the invention, a plurality of anchor rod samples can be fixed on the sample fixing seat and the impact guide plate and uniformly distributed on two sides of the input rod, so that the stress and tension conditions of all the anchor rod samples are the same, and the assumption of uniform stress distribution (dynamic balance) of the anchor rod test piece is met; simultaneously the input rod, dodge the coaxial setting of hole and impact bearing disc for the input rod is even to the impact effort that strikes bearing disc's effect on every stock sample, satisfies the one-dimensional stress wave hypothesis.
According to the invention, the avoidance space is arranged on the sample fixing seat, so that the end part of the input rod is abutted to the impact bearing disc, the size of the test device is reduced, and the applicability of the test device is improved.
The second guide holes and the first guide holes which are in one-to-one correspondence are coaxially arranged on the sample fixing seat and the impact guide plate, and the first guide holes and the second guide holes realize the support and the guide of the anchor rod sample and simultaneously meet the coaxiality of an initial state and a motion state; the two ends of the anchor rod sample are respectively in threaded connection with a first connecting nut and a second connecting nut, and the first connecting nut and the second connecting nut are matched with the sample fixing seat and the impact guide plate in a blocking mode, so that the anchor rod sample can be quickly installed, fixed and detached.
According to the invention, the impact bearing plate is detachably connected to the impact guide plate, and the pressure sensor is arranged in the impact bearing plate, so that the impact bearing plate and the pressure sensor can be safely and quickly installed and replaced.
According to the invention, the impact bearing plate and the support workbench are in sliding connection with the sliding chute through the sliding rail, and the cross sections of the sliding rail and the sliding chute are both in a convex shape or in a dovetail groove shape, so that the impact bearing plate has the advantages of simple structure and stable movement.
The impact guide frame and the sample fixing seat are made of high-strength cast steel materials, so that the stability of the system in the impact process is ensured.
The test device has the advantages of convenience in operation, convenience in assembly and disassembly and good stability.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. Wherein:
FIG. 1 is a front view of an embodiment of the present invention;
FIG. 2 is a top view of an embodiment of the present invention;
FIG. 3 is a front view of a sample holder according to an embodiment of the present invention;
FIG. 4 is a view A-A of FIG. 3;
FIG. 5 is a front view of an impact deflector of an embodiment of the present invention;
FIG. 6 is a view B-B of FIG. 5;
fig. 7 is a front view of an input lever fixing frame according to an embodiment of the present invention.
In the figure: 1. supporting a worktable; 11. a slide rail; 2. an input lever; 3. an anchor rod sample; 4. a movable connection portion; 41. an impact guide plate; 411. a first guide hole; 412. a chute; 42. a first fastener; 43. impacting the bearing plate; 5. a fixed connection part; 51. a sample fixing seat; 511. avoiding a space; 512. a second guide hole; 52. a second fastener; 6, a transmitting tube; 7. a buffer device; 8. an input rod fixing frame; 81. an upper fixing frame; 82. a lower fixing frame; 83. and a third guide hole.
Detailed Description
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are for convenience of description of the present invention only and do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. The terms "connected" and "connected" used herein should be interpreted broadly, and may include, for example, a fixed connection or a detachable connection; they may be directly connected or indirectly connected through intermediate members, and specific meanings of the above terms will be understood by those skilled in the art as appropriate.
As shown in fig. 1 to 6, according to an embodiment of the present invention, a multi-connected microscopic NPR anchor rod hopkinson tensile test apparatus is provided, and the test apparatus is used for performing a tensile test on a multi-connected microscopic NPR anchor rod under a high strain rate condition, so as to solve a problem of whether the multi-connected microscopic NPR anchor rod can exhibit a negative poisson's ratio effect caused by structural deformation under a dynamic impact effect.
The Split Hopkinson Pressure Bar (SHPB) test technology is utilized by the multi-connected microscopic NPR anchor rod Hopkinson tensile test device. The Split Hopkinson Pressure Bar (SHPB) test technology is the most basic means for researching the dynamic mechanical properties of materials in the field of impact dynamics, and can be used for actually measuring the dynamic stress-strain curve of the materials under the condition of impact loading and researching the high strain rate behavior of the materials. Two basic effects in impact dynamics are inertia (stress wave) effect and strain rate effect, and the basic theory of the split Hopkinson pressure bar experiment technology relates to the inertia effect (stress wave theory) and the strain rate effect (material dynamics) in the high strain rate experiment, and the two effects are mutually coupled. The experimental technology research materials of the separated Hopkinson pressure bar comprise metal, composite materials, rock, concrete and the like.
The test device comprises a support workbench 1, an input rod 2, an anchor rod sample 3, a movable connecting part 4 and a fixed connecting part 5; the supporting workbench 1 is provided with a launching tube 6 and a buffer device 7, the launching tube 6 is used for launching a striking rod (the striking rod is not shown in the figure), and the striking rod can strike the input rod 2 along the axial direction of the input rod 2. The input rod 2 is arranged on the support workbench 1 in a sliding mode, the input rod 2 is coaxially and adjacently arranged with the launching tube 6, and the impact rod impacts the input rod 2 along the axial direction of the input rod 2 and is used for enabling the input rod 2 to move along the axial direction; the movable connecting part 4 is arranged between the input rod 2 and the buffer device 7, and the movable connecting part 4 is arranged on the supporting workbench 1 in a sliding manner along the axial direction of the input rod 2; the fixed connecting part 5 is fixed on the supporting workbench 1; one end of an anchor rod sample 3 is fixed on the fixed connecting part 5, the other end of the anchor rod sample 3 is fixed on the movable connecting part 4, and one end of the input rod 2, which is far away from the launching tube 6, is abutted against the movable connecting part 4 and is used for transmitting the impact force of the impact rod to the anchor rod sample 3 through the movable connecting part 4; the anchor rod sample 3 and the input rod 2 are arranged in an overlapped mode in the axial direction of the input rod 2, the axis of the anchor rod sample 3 is parallel to the axis of the input rod 2, the input rod 2 is arranged between the launching tube and the movable connecting portion 4, and the movable connecting portion 4 is located between the fixed connecting portion 5 and the buffer device 7; the experimental device further comprises a force measuring element, wherein the force measuring element is arranged on the movable connecting part and is used for detecting the impact acting force of the input rod on the movable connecting part.
In the specific embodiment of the invention, an even number of anchor rod samples 3 are uniformly distributed on two sides of an input rod 2, one end of each anchor rod sample 3 is connected with a fixed connecting part 5 fixedly arranged on a supporting workbench 1, the other end of each anchor rod sample 3 is connected with a movable connecting part 4, the movable connecting parts 4 are in sliding connection with the supporting workbench 1 along the axial direction of the input rod 2, and the input rod 2 capable of moving along the self axial line passes through an avoidance space of the fixed connecting parts 5 and then is abutted against the movable connecting parts 4; the input rod 2 is impacted by ejecting a high-speed moving impact rod to the input rod 2 through the launching tube 6, so that the input rod 2 moves along the axis direction of the input rod and impacts the movable connecting part 4, the movable connecting part 4 drives the multi-anchor rod sample 3 to move along the axis direction of the input rod 2 under the action of impact load, and the fixed connecting part 5 connected with the anchor rod sample 3 hinders the axial movement of the anchor rod sample 3; the tensile test of the multi-connection anchor rod sample 3 is realized through the driving action of the movable connecting part 4 on the anchor rod sample 3 and the blocking action of the fixed connecting part 5 on the anchor rod sample 3, so that the tensile mechanical property of the microscopic NPR anchor rod under the condition of high strain rate is obtained.
Further, the fixed connection part 5 comprises a sample fixing seat 51 and a second fastening piece 52; the sample fixing seat 51 is fixedly arranged on the supporting workbench 1, an avoiding space 511 and a second guide hole 512 are arranged on the sample fixing seat 51, the avoiding space 511 is used for the input rod 2 to pass through, and the second guide hole 512 is used for the anchor rod sample 3 to pass through. The even number of second guide holes 512 are symmetrically arranged on two sides of the first horizontal plane and the first vertical plane, and the second guide holes 512 are used for supporting and guiding the anchor rod sample 3; the avoidance spaces 511 are symmetrically provided on both sides of the first vertical surface, and the avoidance spaces 511 are used for the input rod 2 to pass through the sample fixing base 51 and abut against the movable connecting portion 4. Anchor rod sample 3 equipartition is in the both sides of input rod 2 for the atress tensile condition of each anchor rod sample 3 is the same during the experiment, with the hypothesis that satisfies anchor rod sample 3 stress evenly distributed (dynamic balance). The anchor rod samples 3 are slidably connected in the second guide holes 512 in a one-to-one correspondence manner, one ends of the anchor rod samples 3 extend out of the second guide holes 512 and are connected with the second fastening pieces 52, and the second fastening pieces 52 and the sample fixing seats 51 form stop matching so as to prevent the anchor rod samples 3 from moving along the axial direction of the input rod 2. And the second fastener 52 is matched with the sample fixing seat 51 in a stop manner, so that one end of the anchor rod sample 3 is connected and fixed with the fixed connecting part 5.
In the embodiment of the present invention, the second fastening member 52 is a second coupling nut, the end of the anchor rod sample 3 is provided with an external thread section, and the second fastening member 52 is threadedly coupled to the anchor rod sample 3, thereby facilitating the assembly and disassembly of the anchor rod sample 3.
Further, the movable connecting portion 4 includes an impact guide plate 41 and a first fastening member 42; the impact guide plate 41 is connected with the support workbench 1 in a sliding manner along the axial direction of the input rod 2 and is positioned between the sample fixing seat 51 and the buffer device 7; the impact guide plate 41 is provided with a force measuring element and a first guide hole 411, the first guide hole 411 is used for one end of the anchor rod sample 3 to pass through, and the first guide hole 411 and a second guide hole 512 which are penetrated by the same anchor rod sample 3 are coaxially arranged; the first guide hole 411 is used to support and guide the anchor rod specimen 3. The anchor rod samples 3 are slidably connected in the first guide holes 411 in a one-to-one correspondence manner, one end of the anchor rod sample 3 extends out of the first guide hole 411 and is fixedly connected with the first fastening piece 42, and the first fastening piece 42 and the impact guide plate 41 form a first stop fit, so that the anchor rod sample 3 is driven to move along the axial direction of the input rod 2 through the movement of the impact guide plate 41. The first end of the anchor rod sample 3 is fixedly connected with the fixed connecting part 4 through the first fastener 42 and the first stop matching of the impact guide plate 41.
In the embodiment of the present invention, the first fastening member 42 is a first coupling nut, the end portion of the anchor rod sample 3 is provided with an external thread section, and the first fastening member 42 is threadedly coupled to the anchor rod sample 3, thereby facilitating the assembly and disassembly of the anchor rod sample 3.
Furthermore, an impact bearing plate 43 is detachably connected to one side of the impact guide plate 41 facing the input rod 2, and the impact bearing plate 43 is used for placing a force measuring element, namely the force measuring element is arranged in the impact bearing plate 43; the replacement of the impact bearing plate 43 is achieved by the detachable connection of the impact bearing plate 43 to the impact guide plate 41.
The force measuring element is a pressure sensor. The model of pressure sensor is YFF quartzy pressure electric force sensor, and pressure sensor installs in the center of assaulting the loading board 43, and pressure sensor is used for measuring the impact force of input rod 2, and also pressure sensor is used for measuring the impact force that the stock sample received.
In the detailed description of the inventionIn the embodiment, the impact bearing plate 43 is disk-shaped, the impact bearing plate 43 is coaxially disposed with the input shaft 2, the impact bearing plate 43 has a length of 50mm, an outer diameter of 200mm, a mass of 9.24kg and a density of 7800kg/m3Yield limit of 600MPa, elastic wave speed of 5977 m/s. The impact bearing plate 43 is integrally connected to the impact guide plate 41 by a screw. Through the screw connection of the impact bearing plate 43 and the impact guide plate 41, a quick and safe replacement of the impact bearing plate 43 is achieved. The impact guide plate 41 is provided with a mounting groove which is coaxial with the input rod 2, and the impact bearing plate 43 is mounted in the mounting groove so that one side surface of the impact guide plate 41 is coplanar with one side surface of the impact bearing plate 43. The entire transfer of the impact load is achieved by the coplanar arrangement of the impact carrier plate 43 and the impact guide plate 41.
Further, a slide rail 11 is arranged on the support workbench 1, the slide rail 11 is arranged along the axial direction of the input rod 2, a slide groove 412 is arranged at the bottom of the impact guide plate 41, and the slide rail 11 is slidably connected in the slide groove 412; preferably, the cross sections of the slide rail 11 and the slide groove 412 are convex or dovetail groove type. Through the setting of slide rail 11 and spout 412, realize strikeing the sliding connection of deflector 41 and supporting workbench 1, and the convex character form or the forked tail cell type have stability good, the difficult advantage that breaks away from of slide rail 11 and spout 412.
Further, in this embodiment, the vertical section of the sample fixing seat 51 is U-shaped, the space in the middle of the U-shape is used for forming an avoiding space 511, the two sides of the U-shape are both provided with the second guide holes 512, the two U-shaped sides of the sample fixing seat 51 are respectively provided with three second guide holes 512, and the second guide holes on the two U-shaped sides of the sample fixing seat 51 are symmetrically arranged to ensure that the stress of the anchoring samples fixed on the two sides of the sample fixing seat 51 is the same. In other embodiments, the sample fixing seat 51 is provided with a avoiding hole, the avoiding hole is used for forming the avoiding space 511, the avoiding hole is coaxially arranged with the input rod 2, and the inner diameter of the avoiding hole is greater than or equal to the outer diameter of the input rod 2, so that the sample fixing seat 51 can have better structural strength, and the fixing seat 51 can bear larger external force.
In this embodiment, the number of the second guide holes 512 on the sample holder 51 is even, and in other embodiments, the number of the second guide holes 512 on the sample holder 51 may also be odd, and at this time, the number of the second guide holes 512 on the two U-shaped sides of the sample holder 51 is different.
Further, at least two input rod fixing frames 8 are arranged on the supporting workbench 1, each input rod fixing frame 8 comprises an upper fixing frame 81 and a lower fixing frame 82, first connecting through holes are formed in the left side and the right side of the upper fixing frame 81, first threaded holes are formed in the left side and the right side of the lower fixing frame 82, and connecting bolts enabling the upper fixing frame 81 and the lower fixing frame 82 to be connected into a whole are arranged in the first connecting through holes and the first threaded holes; the bottom of the upper fixing frame 81 is provided with an upper semicircular hole, the top of the lower fixing frame 82 is provided with a lower semicircular hole, and the upper semicircular hole and the lower semicircular hole form a third guide hole 83 of the input rod fixing frame 8; the input rod fixing frame 8 is composed of an upper fixing frame 81 and a lower fixing frame 82 which are detachably connected, so that the input rod can be fixed in a third guide hole 83 of the input rod fixing frame 8. The axial movement of the input rod 2 is achieved by the sliding connection of the input rod 2 with the third guide hole 83.
Further, the input rod fixing frame 8, the impact guide plate 41, the impact bearing plate 43, the sample fixing seat 51, the first connecting nut and the second connecting nut are all made of high-strength cast steel materials, the strain rate difference is not large, and the requirement for uniformity is met. The launching tube 6, the input rod fixing frame 8, the sample fixing seat 51 and the buffer device 7 are all fixed on the supporting workbench 1 through high-strength bolts.
The launch tube 6 and the buffer device 7 are both prior art; for example, the launching tube 6 is fixedly arranged at one end of the supporting workbench 1, the buffer device 7 is fixedly arranged at the other end of the supporting workbench 1, and the launching tube 6 can coaxially launch a striking rod (not shown in the figure) moving at a high speed. In this example, the impact rod has a length of 150mm, an outer diameter of 75mm, a mass of 51.6kg, a yield limit of 835MPa, an elastic wave speed of 7565m/s and a density of 7800kg/m3(ii) a The impact rod can obtain different impact speeds and impact energies under the action of different air source pressures, so that different high strain rate conditions are provided for the tensile test of the anchor rod sample 3. The buffer device 7 is used for absorbing the kinetic energy of the impact guide plate 41 and preventing the impact guide plate 41 and the anchor rod sample 3 from further movingThe test safety is improved; the damping device 7 is sometimes also called "absorber" and "energy absorber".
When the multi-connected microcosmic NPR anchor rod Hopkinson tensile test device in the application is used, the impact rod is transmitted by the transmitting tube 6, the impact rod impacts the input rod 2 along the axial direction, the input rod 2 pushes the impact bearing plate 43, so that the impact load received by the input rod 2 is transmitted to the movable connecting part 4, the movable connecting part 4 drives the right end of the anchor rod sample 3 to move rightwards, and the anchor rod sample 3 is elongated under the action of the impact load.
The application also provides a multi-connected microscopic NPR anchor rod Hopkinson tensile test method, the multi-connected microscopic NPR anchor rod Hopkinson tensile test device is used in the multi-connected microscopic NPR anchor rod Hopkinson tensile test method, and the multi-connected microscopic NPR anchor rod Hopkinson tensile test method comprises the following steps:
and step S1, ensuring the safety of the placement position and the surrounding environment of the test device and ensuring the safe and reliable operation.
Step S2, grease is applied to the contact parts of the components in the test device for lubricating the contact parts so as to eliminate the friction effect; specifically, the butter application position includes: the contact position of the input rod 2 and the input rod fixing frame 8, the contact position of the anchor rod sample 3 with the impact guide plate 41 and the sample fixing seat 51, and the contact position of the impact guide plate 41 with the support workbench 1.
Step S3, the launch tube 6, the input rod holder 8, the sample holder 51, the impact guide plate 41, and the absorber 7 are fixed on the support table.
In step S4, the input rod 2 is fixed in the third guide hole of the input rod fixing frame 8.
Step S5, first inserting the anchor rod sample 3 into the second guide hole 512 of the sample fixing seat 51 and the first guide hole 411 of the impact guide plate 41, then screwing the first connection nut and the second connection nut onto the first end and the second end of the anchor rod sample 3, respectively, so that the first connection nut and the impact guide plate 41 form a first stop fit, the second connection nut and the sample fixing seat 51 form a second stop fit, and finally, the end of the input rod 2 abuts against the impact bearing disc 43 of the impact guide plate 41.
And step S6, ensuring that all the joints of the test device are firmly connected.
And step S7, starting the transmitting tube to perform the test, and recording the test data.
In summary, in the technical scheme of the multi-connected microscopic NPR anchor rod hopkinson tensile test device and method provided by the invention, a plurality of anchor rod samples can be fixed on the sample fixing seat and the impact guide plate, and are uniformly distributed on two sides of the input rod, so that the stressed tension conditions of all the anchor rod samples are the same, and the assumption of uniform stress distribution (dynamic balance) of the anchor rod samples is met; simultaneously the input rod, dodge the coaxial setting of hole and impact bearing disc for the input rod is even to the impact effort that strikes bearing disc's effect on every stock sample, satisfies the one-dimensional stress wave hypothesis. In the test device, two ends of an anchor rod sample are respectively connected with the sample fixing seat and the impact guide plate, and the impact guide plate moves along the axial direction of the input rod under the impact action of the input rod on the impact guide plate, so that the dynamic mechanical property test of a plurality of microscopic NPR anchor rods under the condition of high strain rate is realized.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. Many microscopic NPR stock hopkinson tensile test device that ally oneself with, testing device includes the supporting workbench, be equipped with launching tube and buffer on the supporting workbench, the launching tube is used for launching the impact bar, its characterized in that, experimental apparatus still includes:
the input rod is arranged on the supporting workbench in a sliding mode, the input rod is coaxially and adjacently arranged with the launching tube, and the impact rod impacts the input rod along the axial direction of the input rod and is used for enabling the input rod to move along the axial direction;
the movable connecting part is arranged between the input rod and the buffer device, and is arranged on the supporting workbench in an axial sliding manner along the input rod;
the fixed connecting part is fixed on the supporting workbench;
the device comprises an anchor rod sample, a movable connecting part and an input rod, wherein one end of the anchor rod sample is fixed on the fixed connecting part, the other end of the anchor rod sample is fixed on the movable connecting part, and one end of the input rod, which is far away from a launching tube, is abutted against the movable connecting part and is used for transmitting the impact force of an impact rod to the anchor rod sample;
the anchor rod sample and the input rod are arranged in an overlapped mode in the axial direction of the input rod, the axis of the anchor rod sample is parallel to the axis of the input rod, the input rod is arranged between the launching tube and the movable connecting portion, and the movable connecting portion is located between the fixed connecting portion and the buffer device;
and the force measuring element is arranged on the movable connecting part and is used for detecting the impact acting force of the input rod on the movable connecting part.
2. The multi-connected microscopic NPR anchor rod Hopkinson tensile test device of claim 1, wherein the fixed connection portion comprises:
the test piece fixing seat is provided with an avoidance space and a second guide hole, the avoidance space is used for the input rod to pass through, and the second guide hole is used for the anchor rod test piece to pass through;
and one end of the anchor rod sample penetrating through the second guide hole is fixedly connected with the second fastener, and the second fastener is in blocking fit with the sample fixing seat.
3. The multi-connected microscopic NPR anchor rod Hopkinson tensile test device of claim 2, wherein the vertical section of the sample fixing seat is U-shaped, the space in the middle of the U-shaped seat is used for forming an avoiding space, and second guide holes are formed in two sides of the U-shaped seat.
4. The multi-connected microscopic NPR anchor rod Hopkinson tensile test device of claim 2, wherein an avoiding hole is formed in the sample fixing seat, the avoiding hole is used for forming the avoiding space, the avoiding hole and the input rod are coaxially arranged, and the inner diameter of the avoiding hole is larger than or equal to the outer diameter of the input rod.
5. The multi-connected microscopic NPR anchor rod Hopkinson tensile test device of claim 2, wherein the movable connection portion comprises:
the impact guide plate is provided with the force measuring element and a first guide hole, the first guide hole is used for one end of the anchor rod sample to pass through, and the first guide hole and the second guide hole which are penetrated by the same anchor rod sample are coaxially arranged;
the first fastening piece is fixedly connected with one end, penetrating through the first guide hole, of the anchoring sample, and the second fastening piece is in blocking fit with the impact guide plate.
6. The multi-connected microscopic NPR anchor rod Hopkinson tensile test device of claim 5, wherein the second fastener is a nut, and the second fastener is in threaded connection with one end of the anchor rod sample; the first fastener is a nut and is in threaded connection with one end of the anchor rod sample.
7. The multi-connected microscopic NPR anchor rod Hopkinson tensile test device of claim 5, wherein an impact bearing plate is arranged on the impact guide plate, the impact bearing plate is arranged on one side of the impact guide plate, which faces to an input rod, the impact bearing plate is arranged coaxially with the input rod, the impact bearing disc is used for bearing the impact acting force of the input rod, and the side force element is arranged on the impact bearing plate;
preferably, the impact bearing plate is disc-shaped and is connected with the impact guide plate into a whole through a screw;
preferably, the load cell is a pressure sensor.
8. The multi-connected microscopic NPR anchor rod Hopkinson tensile test device of claim 7, wherein a slide rail is arranged on the support workbench, the slide rail is arranged along the axial direction of the input rod, a sliding groove is arranged at the bottom of the impact guide plate, and the slide rail is connected in the sliding groove in a sliding manner;
preferably, the cross sections of the sliding rail and the sliding groove are in a shape of a Chinese character 'ao' or a dovetail groove.
9. The multi-connected microscopic NPR anchor rod Hopkinson tensile test device of any one of claims 1 to 8, further comprising a plurality of input rod fixing frames arranged side by side, wherein third guide holes are formed in the input rod fixing frames, the input rods penetrate through the third guide holes, and the third guide holes are used for supporting the input rods and enabling the input rods to move in an axial direction in a guiding mode.
10. A multi-connected microscopic NPR anchor rod Hopkinson tensile test method is characterized in that the multi-connected microscopic NPR anchor rod Hopkinson tensile test device disclosed by any one of claims 1 to 9 is used in the test method, and the test method comprises the following steps:
step S1, ensuring the safety of the placement position and the surrounding environment of the test device and ensuring the safe and reliable operation;
step S2, grease is applied to the contact parts of the components in the test device for lubricating the contact parts so as to eliminate the friction effect;
step S3, fixing the input rod fixing frame, the sample fixing seat, the impact guide plate and the absorption device on a supporting workbench;
step S4, fixing the input rod in the third guide hole of the input rod fixing frame;
step S5, firstly inserting the anchor rod sample into the second guide hole of the sample fixing seat and the first guide hole of the impact guide plate, then correspondingly screwing the first connecting nut and the second connecting nut on the first end and the second end of the anchor rod sample respectively, enabling the first connecting nut and the impact guide plate to form first stop matching, enabling the second connecting nut and the sample fixing seat to form second stop matching, and finally enabling one end part of the input rod to abut against the impact bearing disc of the impact guide plate;
step S6, ensuring the connection of each connection part of the test device to be firm;
and step S7, starting the transmitting tube to perform the test, and recording the test data.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11771183B2 (en) | 2021-12-16 | 2023-10-03 | Joon Bu Park | Negative Poisson's ratio materials for fasteners |
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Application publication date: 20210518 |