Thick-wall cylinder implosion test structure for studying evolution of multiple shear zones

Abstract

The invention provides a test configuration for researching multi-shear band group evolution. The test configuration comprises an outer cylinder, a base, a top cover, a head plug, a driving tube, a sample and a retainer, an inner cavity, located on the upper portion of the base, of the outer cylinder is filled with explosives. The top cover is mounted at an upper end cylinder opening of the outer cylinder, and a through hole convenient for inserting a detonator is formed in the center along the vertical direction; the driving pipe is located in the outer cylinder, a lower end pipe opening is formed in the upper part of the base, and a head plug is mounted at an upper end pipe opening; the sample is of a hollow structure and is placed in an inner cavity of the driving tube; the retainer is vertically mounted in the sample, the tail of the retainer is connected with the head plug, and the head of the retainer is connected with the base. The device is simple and reasonable in structural design, convenient to mount and dismount and capable of being efficiently used for researching group evolution of multiple shear bands at low cost, the test result of the required strain range can be obtained only by adjusting the retainer, and the economic cost in the test process is greatly saved.

Description

Technical Field

[0001] The invention relates to the field of experimental technology, and in particular to a thick-walled cylinder implosion test configuration for studying the evolution of multiple shear bands. Background Art

[0002] Shear bands are dissipative structures with characteristic thickness under high strain rate deformation, which often lead to catastrophic failure. Therefore, the study of shear bands is of great significance for a deeper understanding of material failure.

[0003] The existing experimental techniques for studying shear bands include the dynamic shear technology based on the Hopkinson pressure bar. This test can generate a forced shear zone by loading the "hat-shaped" specimen, and the shear band is usually generated in this area. Since the dynamic shear technology is relatively mature and the specimen size is about 10 mm, the cost is low, and different cutoff strains can be controlled to conduct multiple tests to study the evolution of shear bands. The other is the thick-walled cylinder implosion technology based on the charge structure proposed by Nesterenko, which is usually called the TWC experimental technology. Compared with the "hat-shaped" shear, this experiment can not only study the initiation and evolution of a single shear band, but also the shear band is generated periodically from the inner ring of the thick-walled cylinder. This experiment is also a very effective means to study the collective behavior of shear bands, which is closer to the phenomenon of multiple shear bands generated under actual working conditions. In addition, since there is no forced shear area in the TWC technology, the emergence of shear bands can better reflect the "self-organization" characteristics of the material itself. However, a TWC experiment can only obtain multiple shear bands under one strain in one detonation. Not only is the size of each test specimen about 70 mm long, but the corresponding supporting parts also require additional design. More importantly, since it involves the loading and detonation of explosives, the cost of the test is greatly increased, limiting the application of TWC technology.

[0004] When the external explosive is detonated, the driving tube and the sample will collapse inward under the action of the detonation. In the traditional TWC test technology, the stopper is designed as a stopper tube. The outer diameter of the stopper tube is the same as the inner diameter of the sample. The final strain of the test is controlled by controlling the inner diameter of the stopper tube. When the inside of the stopper tube is compacted, the deformation stops. Since the inner and outer diameters of the stopper tube are uniformly distributed in the longitudinal direction, only one strain can be obtained in one experiment. Assume that the inner and outer diameters of the stopper tube are r and r respectively. in ,r out , the inner diameter of the sample after deformation and compaction satisfies:

[0005] r f 2 =r out 2 -r in 2 (1);

[0006] The effective strain can be expressed as:

[0007]

[0008] It can be seen that when the inner and outer diameters of the stop tube are determined, the cutoff strain of the sample is also determined; therefore, the application scope of the traditional TWC test technology is relatively narrow and cannot be widely used to study the group evolution of multiple shear bands; at the same time, the existing technology can only obtain one strain in one experiment, the experimental cost is high, the experimental progress is slow and it is relatively complicated.

[0009] To sum up, it is necessary to make further innovations on existing technologies. Summary of the invention

[0010] In view of the technical problems existing in the above-mentioned background technology, the present invention proposes an experimental configuration for studying the group evolution of multiple shear bands. The structural design is simple and reasonable, and the installation and disassembly are convenient. It can be used to study the group evolution of multiple shear bands at low cost and high efficiency. All components can be mass-produced, and the test results of the required strain range can be obtained by simply adjusting the stopper, which greatly saves the economic cost in the test process.

[0011] In order to solve the above technical problems, the present invention provides an experimental configuration for studying the evolution of multiple shear band groups, which includes an outer cylinder, a base, a top cover, a head plug, a drive tube, a sample and a stopper; the outer cylinder is matched and installed on the upper part of the base, and the inner cavity of the outer cylinder located at the upper part of the base is filled with explosives; the top cover is matched and installed on the upper end of the outer cylinder and a through hole is matched and opened in the center along the vertical direction for inserting the detonator; the drive tube is located inside the outer cylinder, and its lower end pipe mouth is matched and installed on the upper part of the base, and the head plug is matched and installed at the upper end pipe mouth; the sample is a hollow structure, and it is matched and placed in the inner cavity of the drive tube; the stopper is matched and installed vertically inside the sample, its tail is matched and connected to the head plug, and its head is matched and connected to the base.

[0012] The experimental configuration for studying the evolution of multiple shear band groups, wherein: the base and the outer cylinder are concentric structures.

[0013] The test configuration for studying the evolution of multiple shear band groups, wherein: the inner diameter of the driving tube is consistent with the outer diameter of the sample and can be concentrically matched.

[0014] The experimental configuration for studying the evolution of multiple shear band groups, wherein: a boss is matched and convexly provided at the top center of the base, and an outer cylinder installation step is matched and opened at the circumferential edge.

[0015] The experimental configuration for studying the evolution of multiple shear band groups, wherein: the lower end of the outer cylinder is cooperatively connected with the outer cylinder mounting step.

[0016] The experimental configuration for studying the evolution of multiple shear band groups, wherein: the inner wall of the lower end of the driving tube is provided with a lower step hole along the circumferential direction, and the inner wall of the upper end of the tube is provided with an upper step hole along the circumferential direction; the lower end of the driving tube is connected to the boss through the lower step hole.

[0017] The experimental configuration for studying the evolution of multiple shear band groups, wherein: the lower part of the head plug is matched and embedded in the upper stepped hole, and the upper part extends outward from the upper end of the driving tube.

[0018] The experimental configuration for studying the evolution of multiple shear band groups, wherein: the tail of the stopper is connected to the lower end of the head plug, and the head is connected to the top surface of the boss.

[0019] The experimental configuration for studying the evolution of multiple shear band groups, wherein: the top cover is matched and embedded in the upper end of the outer tube and covers the explosive.

[0020] By adopting the above technical solution, the present invention has the following beneficial effects:

[0021] The structural design of the present invention is simple and reasonable, and it is easy to install and disassemble. It can be used to study the group evolution of multiple shear bands at low cost and high efficiency. All components can be mass-produced, and the test results of the required strain range can be obtained only by adjusting the stopper. As long as a detonation test is carried out once, multiple shear bands under various strains can be obtained, which greatly reduces the economic cost of the test process and promotes the study of shear band related issues.

[0022] The sample in the present invention is matched and placed in the inner cavity of the driving tube with the circumferential outer wall close to the inner tube wall of the driving tube, which can protect the sample during detonation loading to prevent ablation; the upper part of the driving tube is connected to the head plug through the upper step hole, which protects the head of the sample and the head plug is supported by the driving tube to a certain extent, avoiding axial compression of the sample.

[0023] The stopper of the present invention is cleverly designed as a gradient structure, and the components are organically combined together through a matching relationship, breaking through the limitation that only one strain state can be obtained in one experiment in the past. Multiple strain states can be obtained in one experiment, and multiple development stages of the evolution of multiple shear band groups can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a schematic cross-sectional structure diagram of the experimental configuration for studying the evolution of multiple shear band groups in the present invention;

[0026] Figure 2 A cross-sectional view of the base of the experimental configuration for studying the evolution of multiple shear band populations in the present invention;

[0027] Figure 3 Cross-section of the drive tube for the experimental configuration used in the present invention to study the evolution of multiple shear band populations. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The present invention is further explained below in conjunction with specific implementation modes.

[0030] like Figure 1-3 As shown, this embodiment provides an experimental configuration for studying the evolution of multiple shear band groups, including an outer cylinder 1, a base 2, a top cover 3, a head plug 4, a driving tube 5, a sample 6 and a stopper 7.

[0031] The base 2 is placed horizontally on the ground, and a boss 21 is provided in the center of the top thereof, and an outer cylinder installation step 22 is provided in the circumferential edge thereof.

[0032] The outer tube 1 is matched and installed on the upper part of the base 2 and is concentric with the base 2; wherein the lower end of the outer tube 1 is matched and connected with the outer tube installation step 22 of the base 2; wherein the inner cavity of the outer tube 1 located on the upper part of the base 2 is filled with explosives 8.

[0033] The top cover 3 is matched and embedded in the upper end of the outer tube 1 and covers the explosive 8; wherein, a through hole is matched and opened in the center of the top cover 3 along the vertical direction for inserting the detonator.

[0034] The driving tube 5 is matched and installed in the upper center of the base 2, and the inner wall of the lower end of the tube mouth is matched with a circle of lower step holes 51 along the circumferential direction, and the inner wall of the upper end of the tube mouth is matched with a circle of upper step holes 52 along the circumferential direction; wherein, the lower end of the driving tube 5 is matched and connected with the boss 21 of the base 2 through the lower step holes 51.

[0035] The lower portion of the head plug 4 is matched and embedded in the upper stepped hole 52 at the upper end of the driving tube 5 , and the upper portion extends outward from the driving tube 5 .

[0036] The sample 6 is matched and placed in the inner cavity of the driving tube 5, and its outer diameter is consistent with the inner diameter of the driving tube 5 and can be concentrically matched; wherein, the circumferential outer wall of the sample 6 is in close contact with the inner tube wall of the driving tube 5, which can protect the sample 6 from ablation during detonation loading.

[0037] The stopper 7 is matched and installed inside the sample 6, with its tail connected to the lower end of the head plug 4 and its head connected to the top surface of the boss 21 of the base 2. In this embodiment, the stopper 7 is similar to a conical structure, and can also be designed as a prism structure.

[0038] Among them, during the test, it is necessary to determine the outer diameter of the stopper 7, and then install the stopper 7 into the sample 6 to cut off the inward compression deformation of the sample 6 and control the final strain. The head and tail of the stopper 7 are respectively connected to the base 2 and the head plug 4 to keep the stopper 7 in the center and not deviate to one side.

[0039] The upper portion of the driving tube 5 is connected to the head plug 4 through the upper stepped hole 52 , thereby protecting the head of the sample 6 . The head plug 4 is supported by the driving tube 5 to a certain extent, thereby avoiding axial compression of the sample 6 .

[0040] The following is a comparison of the specific test results of the existing configuration and the test configuration of the present invention to further illustrate the characteristics of the present invention:

[0041] In the experimental configuration of the present invention for studying the evolution of multiple shear band groups, the driving tube and the sample collapse inward until the deformation is terminated by contact with the stopper. Since the outer diameter of the cone is distributed in a gradient in the longitudinal direction, multiple shear bands under continuously changing strains can be obtained. Assuming that the inner diameter of the sample is R in The minimum and maximum outer diameters of the stopper are r min ,r max , then the minimum and maximum effective strain can be expressed as:

[0042]

[0043] It can be seen that the strain can be adjusted according to the structure of the stopper 7.

[0044] The structural design of the present invention is simple and reasonable, and it is easy to install and disassemble. As long as a detonation test is carried out once, multiple shear bands under various strains can be obtained, which greatly reduces the cost and promotes the research on shear band related issues. All parts can be mass-produced, and the test results of the required strain range can be obtained only by adjusting the stopper, which further saves the economic cost during the test process.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An experimental configuration for studying the evolution of multiple shear band populations, characterized by: The experimental configuration includes an outer cylinder (1), a base (2), a top cover (3), a head plug (4), a driving tube (5), a sample (6) and a stopper (7); The outer cylinder (1) is matched and mounted on the upper part of the base (2), and the inner cavity of the outer cylinder (1) located on the upper part of the base (2) is filled with explosives (8); The top cover (3) is matched and mounted on the upper end of the outer tube (1) and has a through hole in the center thereof in a vertical direction for inserting a detonating cap; The driving tube (5) is located inside the outer tube (1), and the lower end of the driving tube (5) is matched and installed on the upper part of the base (2), and the head plug (4) is matched and installed on the upper end of the driving tube (5). The sample (6) is a hollow structure, which is matched and placed in the inner cavity of the driving tube (5); The stopper (7) is matched and vertically installed inside the sample (6), and its tail is matched and connected to the head plug (4), and its head is matched and connected to the base (2).

2. The experimental configuration for studying the evolution of multiple shear band populations as claimed in claim 1, characterized in that: The base (2) and the outer cylinder (1) are of a concentric structure.

3. The experimental configuration for studying the evolution of multiple shear band populations as claimed in claim 1, characterized in that: The inner diameter of the driving tube (5) is consistent with the outer diameter of the sample (6) and can be concentrically matched.

4. The experimental configuration for studying the evolution of multiple shear band populations as claimed in claim 1, characterized in that: A boss (21) is provided in the center of the top of the base (2), and an outer cylinder mounting step (22) is provided in the circumferential edge.

5. The experimental configuration for studying the evolution of multiple shear band populations as claimed in claim 4, characterized in that: The lower end opening of the outer cylinder (1) is cooperatively connected with the outer cylinder mounting step (22).

6. The experimental configuration for studying the evolution of multiple shear band populations as claimed in claim 4, characterized in that: The inner wall of the lower end of the driving tube (5) is provided with a lower stepped hole (51) in a circumferentially matching manner, and the inner wall of the upper end of the driving tube is provided with an upper stepped hole (52) in a circumferentially matching manner; the lower end of the driving tube (5) is connected to the boss (21) through the lower stepped hole (51).

7. The experimental configuration for studying the evolution of multiple shear band populations as claimed in claim 6, characterized in that: The lower part of the head plug (4) is matched and embedded in the upper stepped hole (52), and the upper part extends outward from the upper end of the driving tube (5).

8. The experimental configuration for studying the evolution of multiple shear band populations as claimed in claim 4, characterized in that: The tail portion of the stopper (7) is connected to the lower end portion of the head plug (4), and the head portion is connected to the top surface of the boss (21).

9. The experimental configuration for studying the evolution of multiple shear band populations as claimed in claim 1, characterized in that: The top cover (3) is matched and embedded in the upper end of the outer tube (1) and covers the explosive (8).

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