CN107389458A - Balancing gate pit based on carbon fibre composite - Google Patents

Abstract

The present invention provides a pressure chamber based on carbon fiber composite material. It mainly includes: a composite material layer, a metal base cylinder, the composite material layer is wrapped around the metal base cylinder, and is made of carbon fiber composite material, a rock sample base is placed in the metal base tube, and the rock sample is placed on the rock sample base Above, a block is placed above the rock sample; the pressure chamber is filled with confining pressure fluid and loaded with confining pressure p, and the axial loading force F acts on the rock sample through the block. The pressure chamber provided by the present invention has low density, high strength, and large elastic modulus. At the same time, the interior is made of metal material, and the edge of the rock sample is not easy to be damaged when the pressure chamber is repeatedly disassembled and replaced, and the service life is improved. The working mode of the pressure chamber provided by the invention can be applied to occasions where the axial pressure and surrounding pressure of the pressure chamber are relatively large, and can be applied to large-scale rock and soil testing machines.

Description

Pressure chambers based on carbon fiber composites

technical field

The invention relates to the technical field of rock and soil testing, in particular to a pressure chamber based on carbon fiber composite materials.

Background technique

The rock and soil testing machine is a basic scientific test instrument for studying the stress and strain relationship of rock and soil. It is composed of an axial pressure system, a confining pressure system and a temperature control system. The sample force is applied to the sample through the pressure chamber, and at the same time, the upper and lower end surfaces of the sample and the middle of the sample are respectively placed in different temperature environments through the temperature control system, thereby simulating various conditions of the sample at different temperatures. Actual working conditions. Most of the traditional rock testing machines can only measure the stress-strain relationship curve of the rock sample, but cannot monitor and obtain images of the crack generation and development process of the rock during the cracking process.

In recent years, rock test technology has made great progress, so more and more test conditions have been proposed. The deformation of rock samples under multi-field coupling is now a research hotspot. The above multi-fields usually include pressure field, temperature field and electromagnetic field and so on.

With the continuous improvement and development of computer technology, CT (Computed Tomography, computerized tomography) recognition technology has been applied to rock and soil tests, which provides a technical basis for observing the fracture process of rock samples. In order to dynamically observe the deformation of each longitudinal section of the rock and soil sample during the test, it is necessary to make the rock sample and the CT scanner rotate relatively during the test.

The Lanzhou Institute of Glaciology and Geocryology, Chinese Academy of Sciences has used CT testing technology to carry out geotechnical triaxial tests. What they used was to place the strain-type triaxial pressure chamber directly into the CT machine for scanning. This CT scanning method is only suitable for occasions where the axial pressure of the pressure chamber and the surrounding pressure are low, and it is not suitable for large rock and soil testing machines. Be applicable.

Invention patent CN 200620096213.X discloses an all-round scanning geotechnical CT triaxial instrument, which is a triaxial instrument made of all non-metal, which can not only scan transverse sections, but also can scan longitudinal (axial) sections scan. However, this triaxial instrument is only suitable for occasions where the axial pressure and confining pressure are small, and is not suitable for large-scale rock and soil testing machines.

Contents of the invention

An embodiment of the present invention provides a pressure chamber based on a carbon fiber composite material, so as to effectively use the pressure chamber for geotechnical tests.

In order to achieve the above object, the present invention adopts the following technical solutions.

A carbon fiber composite based pressure chamber comprising:

Composite material layer (5), metal base cylinder (6), the composite material layer (5) is wrapped around the periphery of the metal base cylinder (6), and is made of carbon fiber composite material, and the inside of the metal base cylinder (6) A rock sample base (7) is placed, a rock sample (8) is placed on the rock sample base (7), and a pad (9) is placed above the rock sample (8);

The pressure chamber is filled with confining pressure fluid and loaded with confining pressure p, and the axial loading force F acts on the rock sample 8 through the pad (9).

Further, the outer diameters of both ends of the pressure chamber are larger than the outer diameter of the middle part.

Further, the wall thickness of the two end parts of the metal base cylinder is greater than that of the middle part, and it is processed by using a uniform metal cylinder whose inner and outer circles are concentric.

Further, the metal base cylinder (6) is made of low-density metal material.

Further, the composite material layer (5) includes a horizontal and vertical carbon fiber layer one (10), an adhesive (11), an oblique carbon fiber layer (12), a horizontal and vertical carbon fiber layer two (13) and a hardened layer (14).

further,

Coating adhesive (11) on the outer circle surface of metal base tube (6), and winding several layers of horizontal and vertical carbon fiber cloths soaked in adhesive (11) form horizontal and vertical carbon fiber layer (10); (10) wind several layers of oblique carbon fiber cloth soaked in adhesive (11) to form an oblique carbon fiber layer (12), and then wind several layers of oblique carbon fiber cloth soaked in adhesive (11) on the oblique carbon fiber layer (12). ) horizontal and vertical carbon fiber cloth forms horizontal and vertical carbon fiber layer two (13), and the outermost layer of the composite material layer (5) is coated with a hardened layer (14).

Further, the adhesive (11) includes phenolic resin.

Further, the winding process of the carbon fiber material of the composite material layer (5) is carried out in a vacuum environment, and the outer surface of the composite material layer (5) is machined to ensure roundness.

Further, the pressure chamber, the radiation source (3) and the industrial CT (1) constitute a rock mechanics testing machine, and the radiation source (3) and the industrial CT (1) are distributed on both sides of the pressure chamber of the testing machine, As the axial loading force F increases, cracks appear in the rock sample 8, and the X-rays emitted by the ray source (3) penetrate the pressure chamber and the rock sample (8), and are imaged in the industrial CT (1).

It can be seen from the technical solutions provided by the above-mentioned embodiments of the present invention that the pressure chambers based on carbon fiber composite materials provided by the embodiments of the present invention are reinforced by internal metal materials and external carbon fibers, so that the density of the pressure chambers is low, the strength is high, and the elastic modulus Large, and the interior is made of metal materials, and the edge of the rock sample is not easily damaged after repeated disassembly and replacement in the pressure chamber, which improves the service life. The working mode of the pressure chamber based on the carbon fiber composite material provided by the embodiment of the present invention can be applied to occasions where the axial pressure and the surrounding pressure of the pressure chamber are relatively large, and can be applied to large-scale rock and soil testing machines.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description, or may be learned by practice of the invention.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For Those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is a schematic diagram of the working scene of a rock mechanics testing machine based on a carbon fiber composite pressure chamber provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of the internal structure of a pressure chamber based on a carbon fiber composite material provided by an embodiment of the present invention;

Fig. 3 and Fig. 4 are schematic diagrams of a pressure chamber processing process based on carbon fiber composite materials provided by an embodiment of the present invention;

In the figure: Industrial CT1, main body of rock mechanics testing machine 2, ray source 3, pressure chamber 4, composite material layer 5, metal base cylinder 6, rock sample base 7, rock sample 8, pad 9, horizontal and vertical carbon fiber Layer one 10, glue 11, oblique carbon fiber layer 12, horizontal and vertical carbon fiber layer two 13, hardened layer 14.

detailed description

Embodiments of the present invention are described in detail below, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

Those skilled in the art will understand that unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the word "comprising" used in the description of the present invention refers to the presence of said features, integers, steps, operations, elements and/or components, but does not exclude the presence or addition of one or more other features, Integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Additionally, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should also be understood that terms such as those defined in commonly used dictionaries should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless defined as herein Explanation.

In order to facilitate the understanding of the embodiments of the present invention, several specific embodiments will be taken as examples for further explanation below in conjunction with the accompanying drawings, and each embodiment does not constitute a limitation to the embodiments of the present invention.

Large-scale geotechnical testing machines have relatively large axial and confining pressures, so metal sample cylinders must be used, so high-energy CT machines must be used accordingly. Due to the large size of the large-scale geotechnical testing machine, it cannot be directly placed in the high-energy CT machine for scanning, so the sample cylinder part of the testing machine must be designed as a rotatable part.

The material of the pressure chamber part of the current testing machine is usually made of carbon steel, alloy steel and other materials, and some special rock mechanics testing opportunities use aluminum alloy materials. However, when pressure chambers made of these materials are used in CT scans, the density of steel is too high for X-rays to penetrate easily. Although the aluminum alloy has a lower density, its tensile strength is lower, and it usually bears the same load, and its thickness is much thicker than that of the steel pressure chamber. Therefore, the embodiment of the present invention proposes a carbon fiber composite material-based pressure chamber and its manufacturing process.

The working scene of a rock mechanics testing machine based on a carbon fiber composite material pressure chamber provided by an embodiment of the present invention is shown in FIG. The radiation source 3 and the industrial CT1 are distributed on both sides of the pressure chamber 4 of the testing machine. The high-energy rays emitted by the radiation source 3 pass through the pressure chamber 4 and the rock sample 8 therein, and are imaged on the industrial CT3.

2 is a schematic diagram of the internal structure of a pressure chamber based on carbon fiber composite materials provided by an embodiment of the present invention. The pressure chamber 4 includes a composite material layer 5 and a metal base cylinder 6. The composite material layer 5 is wrapped around the periphery of the metal base cylinder 6. A rock sample base 7 is placed in the metal base cylinder 6 , a rock sample 8 is placed on the rock sample base 7 , and a spacer 9 is placed above the rock sample 8 . The pressure chamber is filled with confining pressure fluid and loaded with confining pressure p. The axial loading force F acts on the rock sample 8 through the pad 9. As the axial pressure increases, the rock sample 8 cracks. During this process, the X-rays emitted by the ray source 3 penetrate the pressure chamber and the rock sample 8, and are imaged in the industrial CT1. The reaction force of confining pressure p and axial loading force F in the pressure chamber is borne by the pressure chamber.

The outer diameters of both ends of the above-mentioned pressure chamber 4 are larger than the outer diameter of the middle part, which is convenient for the clamping of the connecting mechanism and bears the reaction force of the axial loading force F. The wall thickness of the middle part of the pressure chamber is thinner than that of the two ends, which is convenient for the penetration of X-rays .

Figure 3 and Figure 4 are schematic diagrams of a pressure chamber processing process based on carbon fiber composite materials provided by the embodiment of the present invention. Layer two 13, hardened layer 14. The metal base cylinder 6 is a metal cylinder with larger wall thickness at both ends and thinner wall thickness in the middle. It is processed by a uniform metal cylinder with inner and outer circles concentric. The outer diameter of the middle part is smaller than that of the two ends. It is processed into a taper of 5° to 45°, forming a structure with thick walls at both ends and thin walls in the middle. Sufficient length is reserved at both ends of the thick-walled cylinder, which is convenient for clamping and rotating, so as to wind the carbon fiber material. In this way, the metal base cylinder 6 doubles as a mold for manufacturing the composite material pressure chamber.

The pressure chamber uses the metal base cylinder 6 as the base cylinder of composite carbon fiber, and the metal base cylinder (6) is made of low-density metal material. As a preference, aluminum alloy material is used in this embodiment. The composite material layer 5 is formed by using multi-layer carbon fiber composite layers, that is, the first horizontal and vertical carbon fiber layer 10 , the oblique carbon fiber layer 12 and the second horizontal and vertical carbon fiber layer 13 , so as to strengthen the strength of the metal base cylinder 6 .

The manufacturing process of the composite material layer 5 is as follows:

First, the adhesive 11 is uniformly coated on the outer surface of the metal base cylinder 6, and several layers of horizontal and vertical carbon fiber cloth soaked in the adhesive 11 are wound to form a horizontal and vertical carbon fiber layer 10; Layers of oblique carbon fiber cloth soaked with adhesive 11 form an oblique carbon fiber layer 12, and then several layers of transverse and longitudinal carbon fiber cloth impregnated with adhesive 11 are wound on the oblique carbon fiber layer 12 to form a transverse and longitudinal carbon fiber layer 2 13. The outermost layer of the composite material layer (5) is coated with a hardened layer 14. The carbon fiber layer should be continuous and uniform to increase the axial elastic modulus of the pressure chamber, and the outermost layer should be hardened to increase the strength of the pressure chamber surface. The adhesive 11 is a high temperature resistant adhesive, and the embodiment of the present invention uses a phenolic resin.

During the winding process of carbon fiber reinforced materials, it is carried out in a vacuum environment to avoid mixing air bubbles in the material, which will affect the uniformity of the material and further affect the quality of CT imaging.

After the metal base cylinder 6 and the composite material layer 5 are solidified, the outer surface is machined to ensure the roundness, and the excess composite layer and metal material at both ends are removed to complete the manufacture of the pressure chamber, and its structure is shown in Figure 4.

In summary, the carbon fiber composite material-based pressure chamber provided by the embodiment of the present invention is reinforced by internal metal materials and external carbon fibers, so that the pressure chamber has low density, high strength, and large elastic modulus. At the same time, the interior is made of metal materials. The edge of the rock sample is not easy to be damaged by repeated disassembly and assembly of the chamber, which improves the service life. The working mode of the pressure chamber based on the carbon fiber composite material provided by the embodiment of the present invention can be applied to occasions where the axial pressure and the surrounding pressure of the pressure chamber are relatively large, and can be effectively applied to large-scale geotechnical testing machines.

The ray penetration effect of the rock mechanics testing machine based on this carbon fiber pressure chamber is good, and it is convenient to apply industrial CT to continuously scan the internal dynamics of rock and soil samples under axial loading, which is conducive to deepening the study of rock and soil mechanics.

Those skilled in the art can understand that the accompanying drawing is only a schematic diagram of an embodiment, and the modules or processes in the accompanying drawing are not necessarily necessary for implementing the present invention.

Those of ordinary skill in the art can understand that: the components in the device in the embodiment can be distributed in the device in the embodiment according to the description in the embodiment, and can also be changed and located in one or more devices different from the embodiment. The components in the above embodiments can be combined into one component, and can also be further divided into multiple subcomponents.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (9)

1. A kind of 1. balancing gate pit based on carbon fibre composite, it is characterised in that including：

   Composite layer (5), Metal Substrate cylinder (6), the composite layer (5) are wrapped in the periphery of the Metal Substrate cylinder (6), adopted Made of carbon fibre composite, be placed with rock sample pedestal (7) in the Metal Substrate cylinder (6), rock sample (8) is positioned over On the rock sample pedestal (7), cushion block (9) is placed with above the rock sample (8)；

   Confined pressure liquid is filled in the balancing gate pit and loads confined pressure p, axially loaded power F the rock is acted on by the cushion block (9) On sample (8).
2. 2. the balancing gate pit according to claim 1 based on carbon fibre composite, it is characterised in that the two of the balancing gate pit External diameter is held to be more than the external diameter of center section.
3. 3. the balancing gate pit according to claim 2 based on carbon fibre composite, it is characterised in that the Metal Substrate cylinder (6) wall thickness of two end portions is more than the wall thickness of center section, is process using the concentric uniform metallic cylinder of inside and outside circle.
4. 4. the balancing gate pit according to claim 3 based on carbon fibre composite, it is characterised in that the Metal Substrate cylinder (6) made using low density-metal material.
5. 5. the balancing gate pit based on carbon fibre composite according to any one of Claims 1-4, it is characterised in that described It is fine that composite layer (5) includes transverse and longitudinal carbon fiber layer one (10), adhesive (11), oblique carbon fiber layer (12), transverse and longitudinal carbon Tie up layer two (13) and hardened layer (14).
6. 6. the balancing gate pit according to claim 5 based on carbon fibre composite, it is characterised in that in Metal Substrate cylinder (6) Outer round surface on apply adhesive (11), and writhing number layer infiltrated adhesive (11) transverse and longitudinal carbon cloth formed transverse and longitudinal Carbon fiber layer (10)；Writhing number layer has infiltrated the oblique carbon cloth of adhesive (11) again on transverse and longitudinal carbon fiber layer one (10) Oblique carbon fiber layer (12) is formed, writhing number layer has infiltrated the transverse and longitudinal of adhesive (11) again on the oblique carbon fiber layer (12) Transverse and longitudinal carbon fiber layer two (13) is formed to carbon cloth, the outermost layer of the composite layer (5) coats hardened layer (14).
7. 7. the balancing gate pit according to claim 6 based on carbon fibre composite, it is characterised in that the adhesive (11) Including phenolic resin.
8. 8. the balancing gate pit according to claim 6 based on carbon fibre composite, it is characterised in that the composite layer (5) winding process of carbon fibre material is carried out in vacuum environment, and the outer surface of the composite layer (5) passes through machining Ensure circularity.
9. 9. the balancing gate pit according to claim 1 based on carbon fibre composite, it is characterised in that the balancing gate pit is with penetrating Line source (3), industry CT (1) form rock mechanics experiment machine, and the radiographic source (3) and the industry CT (1) are distributed in testing machine The both sides of balancing gate pit, with axially loaded power F increase, the rock sample 8 is cracked, and radiographic source (3) sends X ray and worn Saturating balancing gate pit and rock sample (8), are imaged in industry CT (1).