WO2020134578A1

WO2020134578A1 - Positioning and centering system and method for true triaxial hopkinson pressure bar

Info

Publication number: WO2020134578A1
Application number: PCT/CN2019/115479
Authority: WO
Inventors: 朱建波; 谢和平; 李玉龙; 汤忠斌; 索涛; 赵坚; 周韬
Original assignee: 深圳大学
Priority date: 2018-12-26
Filing date: 2019-11-05
Publication date: 2020-07-02
Also published as: CN109668775A; CN109668775B

Abstract

A positioning and centering system and method for a true triaxial Hopkinson pressure bar. A positioning guide centering box (6) is a cube. Square holes are left on the six surfaces of the positioning guide centering box (6). The size of the square holes on the six surfaces is the same as the size of the square bars (9, 11, 13, 15, 17, 19) of a Hopkinson bar. The size of the inner cavity of the positioning guide centering box (6) is the same as the size of a cubic sample (20). The positioning guide centering box (6) is designed as four symmetrical parts (1, 2, 3, 4). The centering method comprises: step 1: assembling a positioning guide centering box (6); step 2: placing the positioning guide centering box (6) at the central position of a central cube box (7); and step 3: using an infrared laser measuring instrument to assist in achieving quick and precise alignment of a three-axis six-direction pressure bar. The structure design of the positioning guide centering box (6) and the cube box (7) can ensure quick and precise positioning and centering installation of test materials such as rock and concrete. The infrared laser measuring instrument auxiliary installation system ensures quick alignment of the three-axis six-direction pressure bar.

Description

System and method for positioning and centering a true three-axis Hopkinson pressure bar

[0001] The present invention relates to the field of dynamic mechanical property testing of materials such as rock and concrete, and particularly relates to an accurate positioning centering device and method for a true three-axis dynamic and static combined loading Hopkinson rod.

Background technique

[0002] At present, the dynamic mechanical properties of rock and concrete and other materials at home and abroad are mainly based on Hopkinson rod system dynamic impact experimental research. The utility model with the patent number 201620574575.9 provides a rock Hopkinson impact loading experiment device based on true triaxial static load. Although the device can realize the rock static true triaxial pre-load static pressure, the utility model patent has not been resolved The problem of accurate positioning and centering when installing rock samples.

[0003] The Hopkinson impact loading experimental device based on true triaxial static load can reflect the true triaxial stress state in engineering practice. However, accurate positioning alignment is the core of the test system. The positioning center bracket in the utility model Hopkinson rod system with the patent number 201620574575.9 cannot achieve the test effect of accurate positioning alignment, which not only makes the sample installation process cumbersome, but also is not conducive to guarantee Test accuracy and repeatability of results; In addition, due to the inaccurate and reliable alignment of the true triaxial compression bar, it is easy to cause eccentricity in the alignment of the compression bar and the test specimen, which is likely to cause compression during high-amplitude dynamic impact loading The eccentric moment between the rod and the test specimen damages the compression rod and results in unreliable test results.

Summary of the invention

technical problem

Solution to the problem

Technical solution

[0004] The purpose of this patent invention is to introduce a precise positioning centering device to ensure that the sample can be accurately and quickly positioned and installed, so that the test results are more accurate and reliable.

[0005] In order to solve the problems in the prior art, the present invention provides a true three-axis Hopkinson pressure bar positioning centering system, the positioning guide centering box is a cube, and the positioning guide centering box is reserved for six sides Square hole, the size of the hole above the six faces is the same as the size of the Hopkinson bar square bar; the size of the inner cavity of the positioning guide centering box Consistent with the size of the cubic sample, the positioning guide centering box is designed as a symmetrical four part.

[0006] As a further improvement of the present invention, the six sides of the positioning guide centering box are reserved with round holes, the size of the round hole is consistent with the size of the screw, and the four parts are connected by a screw and a nut to The split positioning guide centering box is combined into a whole structure and used to quickly and accurately place the positioning guide centering box at the center position of the square box of the central cube.

[0007] A positioning method for a true three-axis Hopkinson pressure bar positioning system includes the following steps:

[0008] Step 1: Assemble the positioning guide centering box, first connect the lower two parts of the positioning guide centering box, and then install the third part, then connect the lower two parts with the upper third part, and then install Into the cube sample, and then install the last part, fixed connection, forming a complete positioning centering device

[0009] Step 2: Install the positioning guide alignment box cushion block, first place the removable cushion block in the center of the bottom surface of the center cube box, and then fix the cushion block in the center cube box with bolts through the cushion block bolt positioning holes The center of the bottom surface, so as to provide an auxiliary platform for quickly and accurately positioning the positioning centering box at the center of the square box of the central cube;

[0010] Step 3: After the step 2 is installed, the positioning guide centering box of step 1 is placed at the center of the upper surface of the block of the step 2, and then the positioning holes of the centering box bolts are positioned by bolts through the positioning guide The positioning guide centering box is fixed at the center of the upper surface of the block, so that the positioning guide centering box is quickly and accurately placed at the center of the center cube box, and is used for installation with each side of the center cube box The square holes of the square rod are completely centered and aligned, and then the square rods are placed along the X, Y, and Z direction square holes of the central cube square box and the centering box, respectively. At this point, the step of rapid and accurate positioning is completed;

[0011] Step 4: After the installation in step 3 is completed, the infrared laser measuring instrument is used to assist in achieving fast and accurate alignment of the three-axis six-direction pressing rod. The working principle and specific implementation take the X direction as an example, accurate alignment before, X -Place the square rod on the edge of the center cube box, place the infrared laser measuring instrument at A, and emit the infrared laser from A. The infrared laser reaches the B and can measure the distance between AB; after accurate alignment, the X-direction square The rod is in contact with the cube sample, and the position of the infrared laser measuring instrument is fixed during the alignment process. At this time, the infrared laser measuring instrument is at A, and the infrared laser reaches B, where the distance between A and can be measured. The difference between the two measurement distances is the distance between CDs; EF line is the center line of the cube sample and the center cube box, EG is half the side length of the center cube box, HI is half the length of the cube sample side, if the CD spacing And center cube The difference between the half of the side length of the square box and the half of the side length of the cubic sample is equal to CD=EG-HI, which means that the X direction has been accurately aligned and aligned, and the follow-up operation and test process can be continued.

Beneficial effects of invention

Beneficial effect

[0012] The beneficial effects of the present invention are:

[0013] (1) The structural design of the cushion, positioning guide centering box and central cube square box can ensure the rapid and accurate positioning and centering installation of test specimens such as rock and concrete during the true triaxial Hopkinson pressure bar test.

[0014] (2) The infrared laser measuring instrument auxiliary installation system ensures the quick alignment of the three-axis six-direction pressing rod.

[0015] (3) The device and method of the present invention help to ensure the rapid centering and alignment of the three-axis six-direction pressure bar, ensure that the alignment of the pressure bar and the test sample does not occur eccentricity, thereby ensuring high amplitude dynamics During the impact loading process, there will be no damage to the compression rod due to the effect of eccentric moment between the compression rod and the test sample, and to ensure that the test results are reliable

BRIEF DESCRIPTION

[0016] FIG. 1 is a cubic sample;

[0017] FIG. 2a is a schematic view of the installation of the positioning guide device box of FIG. 2b;

[0018] FIG. 3a is a three-dimensional view of a precise positioning centering device;

[0019] FIG. 3b is a three-dimensional view of a cross-section of an accurate positioning centering device;

[0020] FIG. 4a is a front view of the accurate centering front X-direction true three-axis dynamic and static combined loading Hopkinson rod;

[0021] FIG. 4b is a front view of the Hopkinson rod loaded with X-direction true three-axis dynamic and static combination after accurate centering;

[0022] FIG. 4c is a front view of the center cube square box, positioning guide centering box and cube sample combination.

[0023] The names of the corresponding parts in the figures are as follows:

[0024] 1-positioning guide alignment box first part, 2-positioning guide alignment box second part, 3-positioning guide alignment box third part, 4-positioning guide alignment box fourth part, 5-bolt connection Hole, 6-positioning guide centering box, 7-center cube box, 8-X ₊ direction boss, 9-X ₊ direction square bar, lO-X direction boss, l lX direction square bar, 12-Y ₊ Boss, 13-Y ₊ square bar, UY boss, 15-Y _ square bar, 16-Z ₊ boss, 17-Z ₊ square bar, 182 _ boss, 19-Z

Square rod, 20-cubic specimen, 21-block, 22-block bolt positioning hole, 23-positioning guide alignment box Bolt positioning holes.

Invention Example

Embodiments of the invention

[0025] The present invention will be further described below in conjunction with the accompanying drawings.

[0026] The precise positioning centering device of the true three-axis dynamic and static combined loading Hopkinson pressure bar is the core of the three-axis six-way synchronous coordinated control electromagnetic loading Hopkinson bar system. The precise positioning centering device includes positioning guide centering box and infrared laser alignment system. The side of the positioning guide alignment box is reserved with round holes and square holes. The size of the holes above the six faces is the same as the size of the square rod. The square rod passes through the square hole and contacts the cubic sample; the size of the round hole is consistent with the size of the screw. It is used to combine the detachable positioning guide centering box into a whole structure and to quickly and accurately place the positioning guide centering box in the center of the square box of the central cube;

[0027] The size of the inner cavity of the positioning guide centering box is consistent with the size of the cube sample. FIG. 1 is the cube sample 20, and the edge of the cube sample 20 will have 0.5

Chamfering. The purpose is to leave room for deformation of the specimen and to prevent the test specimen from being crushed and deformed to cause the square rods to collide with each other and be damaged.

[0028] The positioning guide centering box is designed as a symmetrical four parts. When installing the positioning guide centering box, first connect the lower two parts of the positioning guide centering box with screws through bolt connection holes, and then install the third part Then, use the screw to connect the lower two parts and the upper third part through the bolt connection hole, then install the cube sample, and then install the last part, and use the screw to connect through the bolt connection hole to form a complete positioning centering device; Then place the positioning guide centering box at the center of the upper surface of the block, and fix the positioning guide centering box at the center of the upper surface of the block through the positioning holes of the positioning guide centering box bolts with bolts, so that the positioning guide centering box Quickly and accurately place it in the center of the center cube box, and align with the square holes on the sides of the center cube box for installing square rods, and then along the X of the center cube box and center box Place square rods on both sides of the square hole in the Y, Z, and Z directions. So far, complete the quick and accurate positioning and alignment steps.

[0029] The infrared laser measuring instrument is then used to assist in achieving fast and accurate alignment of the three-axis six-direction pressure bar. The working principle and specific implementation take the X direction as an example. Figure 4a shows the precise centering front X ₊ square rod 9 is placed on the edge of the central cube square box 7. Place the infrared laser measuring instrument at A and emit infrared laser from A. Infrared When the laser reaches B, the distance between AB can be measured. Figure 4b shows that after accurate centering, the square rod in the X _ direction contacts the cube sample 20. The position of the infrared laser measuring instrument is fixed during the alignment process. At this time, the infrared The laser measuring instrument is at A, When the infrared laser reaches B, the distance between A and B can be measured. The difference between the two measured distances is the distance between CD. In Figure 4c, the EF line is the center line of the cubic sample 20 and the central cubic box 7, and EG is Half of the 7 sides of the center cube box, HI is half of the 20 sides of the cube sample, if the distance between CD and half of the 7 sides of the center cube box and half of the sides of the cube sample 20 are equal (ie CD=EG- HI), then it can be explained that the X direction has completed accurate alignment and alignment, and the follow-up operation and test process can be continued.

[0030] FIG. 3a is a three-dimensional view of a precise positioning centering device, and FIG. 3b is a three-dimensional view of a cross section of the precise positioning centering device. As shown in FIG. 3a, the positioning guide centering box 6 with the cube sample 20 installed is placed in the center cube square box 7 (located on the cushion block 21), and the side of the center cube square box is reserved with square holes, observation holes and Round hole, positioning guide alignment box 6 and center cube box 7 X side square hole side X ₊ square rod 9, the other side X _ square bar 11, Y side square hole side Y ₊ Place the square rod 13 on the other side, place the Y square rod 15 on the other side, and place the Z ₊ square rod 17 on the side of the square hole in the Z direction, Z _

To the square rod 19, the precise positioning and alignment has been completed. In FIG. 3b, the positioning guide centering box 6 has a cushion block 21 below. The cushion block is divided into two parts and is detachable. The cushion block is provided with a cushion bolt positioning hole 22 and a positioning guide centering box bolt positioning hole 23 On the one hand, the cushion block positioning hole 22 can be used to fix the cushion block in the center of the bottom surface of the center cube box, so as to provide an auxiliary platform for quickly and accurately positioning the positioning centering box at the center of the center cube box; On the other hand, the positioning guide alignment box bolt positioning hole 23 can fix the positioning guide alignment box at the center of the upper surface of the block to ensure that the positioning guide alignment box is quickly and accurately placed in the center of the center cubic box Position, and be completely centered and aligned with the square holes on the sides of the central cube box for installing square rods.

[0031] FIG. 4a is a front view of the X-direction true three-axis dynamic and static combination loading Hopkinson rod for precise centering, FIG. 4b is a front view of the X-direction true three-axis dynamic and static combination loading Hopkinson rod for precise centering, and FIG. 4c is The central view of the central cube square box 7, the positioning guide centering box 6, the cushion block 21 and the cube sample 20 are combined.

[0032] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. For a person of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or replacements can be made, which should be regarded as falling within the protection scope of the present invention.

Claims

[Claim 1] A true three-axis Hopkinson pressure bar positioning centering system, characterized in that: the positioning guide centering box is a cube, and the six sides of the positioning guide centering box are reserved with square holes and six faces The size of the upper hole is the same as the size of the square rod of the Hopkinson rod; the inner cavity size of the positioning guide centering box is consistent with the size of the cubic sample, and the positioning guide centering box is designed as a symmetrical four part.

[Claim 2] The true three-axis Hopkinson pressure bar positioning centering system according to claim 1, characterized in that: the positioning guide centering box has six round holes reserved on the six sides, the size of the round hole and the screw The dimensions are the same, and the four parts are connected by a screw and a nut, which are used to combine the detachable positioning guide centering box into an overall structure.

[Claim 3] The method of positioning the centering system of the true three-axis Hopkinson pressure bar according to claim 1 or 2, characterized in that it includes the following steps:

Step 1: Assemble the positioning guide centering box, first connect the lower two parts of the positioning guide centering box, then install the third part, then connect the lower two parts with the upper third part, and then install the cube to try In this way, install the last part and fix the connection to form a complete positioning and alignment device;

Step 2: Install the positioning guide centering box cushion, the centering box cushion is a removable block, first place the centering box cushion in the center of the bottom of the center cube box, and then use bolts to pass through the bolt positioning holes Fix the cushion block in the center of the bottom of the square box of the center cube, so as to provide an auxiliary platform for quickly and accurately positioning the positioning centering box at the center of the center box of the center cube;

Step 3: After the step 2 is installed, place the positioning guide centering box of step 1 at the center of the upper surface of the block of step 2, and then fix the positioning guide centering box with bolts through the bolt positioning holes. The center surface of the upper surface of the cushion block, so that the positioning guide centering box is placed at the center of the center cube box, and is completely centered and aligned with the square holes on the sides of the center cube box for installing square rods, and then Place square rods on both sides of the square hole of the center cube square box and the positioning guide alignment box in the X, Y, and Z directions respectively. At this point, the steps of rapid and accurate positioning alignment are completed;

Step 4: After the installation of Step 3 is completed, use the infrared laser measuring instrument to realize the three-axis The six-direction pressure bar is quickly and accurately aligned. The working principle and specific implementation take the X direction as an example. Precise centering, the X-direction square bar is placed on the edge of the central cube square box, and the infrared laser measuring instrument is placed at A and emitted from A Infrared laser, infrared laser reaches B, can measure the distance between AB; after accurate alignment, the square rod in the X _ direction contacts the cube sample, the position of the infrared laser measuring instrument is fixed during the alignment process, at this time, infrared The laser measuring instrument is at A and the infrared laser reaches B and can measure the distance between A and. The difference between the two measured distances is the distance between CD; EF line is the center line of the cubic sample and the central cube box , EG is half of the side length of the central cube box, and HI is half of the side length of the cube sample. If the difference between the CD spacing and the half of the center cube box side and the half of the cube sample side is equal, CD=EG-HI Then, it can be explained that the X direction has completed accurate alignment and alignment, and the follow-up operation and test process can be continued.