Composite material sample preparation device and preparation method

Abstract

The invention relates to a composite material sample preparation device and method, and the device comprises a main body which is provided with a first surface and a second surface; the sample placing unit comprises placing grooves formed in the first surface and the second surface respectively, the placing grooves extend in the length direction of the main body, the placing grooves are arranged to be matched with test samples, and the placing grooves are oppositely arranged in the thickness direction of the main body; the cover plate unit comprises a first cover plate and a second cover plate, the first cover plate is in contact with the first surface to press the first surface, and the side, facing the main body, of the first cover plate is matched with the main body; the second cover plate is in contact with the second surface to press the second surface, and one side, facing the main body, of the second cover plate is matched with the main body. According to the method, raw materials and cost can be effectively saved, the preparation efficiency is improved, the size and the fiber volume content of the test sample can be adjusted by adjusting the technological parameters such as the number of winding layers and the pressure of the molding press, and it is ensured that the prepared test sample meets the test requirement.

Description

Technical Field

[0001] The invention relates to the technical field of carbon fiber composite material preparation, and in particular to a composite material sample preparation device and a preparation method. Background Art

[0002] Carbon fiber composite materials are inorganic high-performance fibers with a carbon content of more than 90% that are transformed from organic fibers through a series of heat treatments. They are new materials with excellent mechanical properties. They have the inherent characteristics of carbon materials and the softness and processability of textile fibers. They are a new generation of reinforcing fibers. Existing carbon fiber composite test samples are mainly prepared by hand-laying prepregs and preparing them through processes such as vacuum bag pressing or autoclaves to form test samples.

[0003] However, the disadvantage of the existing sample acquisition method is that the cost of high-performance carbon fiber materials is usually high, and the production volume of their prepreg fabrics is low. Therefore, obtaining the corresponding materials by direct purchase often requires a high cost investment, which in turn limits the performance testing of high-performance carbon fiber materials. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is to overcome the deficiencies in the prior art and provide a composite material sample preparation device and method, which can reduce the cost of sample preparation, improve preparation efficiency, and control parameters during the preparation process to achieve convenient adjustment of sample size and fiber volume content, thereby ensuring that the prepared test samples meet the test requirements.

[0005] In order to solve the above technical problems, the present invention provides a composite material sample preparation device for preparing a test sample of a carbon fiber composite material, comprising: A main body having a first surface and a second surface along a thickness direction; A sample placement unit, comprising placement grooves respectively arranged on the first surface and the second surface, the placement grooves extending along the length direction of the main body, the placement grooves being arranged to match the test sample, and the placement grooves being arranged opposite to each other along the thickness direction of the main body; The cover plate unit comprises a first cover plate and a second cover plate, wherein the first cover plate contacts the first surface to press the first surface, and the side of the first cover plate facing the main body is adapted to the main body; the second cover plate contacts the second surface to press the second surface, and the side of the second cover plate facing the main body is adapted to the main body.

[0006] In one embodiment of the present invention, the slot edge of the placement slot is provided with a winding fillet.

[0007] In one embodiment of the present invention, the groove bottom of the placement groove is provided with groove entry fillets at both end edges along the length direction of the main body.

[0008] In one embodiment of the present invention, a clamping unit is further included, wherein the clamping unit includes clamping columns relatively arranged on two sides of the main body, wherein the axial direction of the clamping columns is perpendicular to the length direction of the main body, and the clamping columns are used to be assembled to a winding machine.

[0009] In one embodiment of the present invention, a first positioning piece is provided on the side of the first cover plate that contacts the main body, and a first positioning groove matching the first positioning piece is provided on the main body; a second positioning piece is provided on the side of the second cover plate that contacts the main body, and a second positioning groove matching the second positioning piece is provided on the main body.

[0010] In one embodiment of the present invention, the sample placement unit includes a plurality of first placement grooves arranged on the first surface, and a plurality of second placement grooves arranged on the second surface, and the projections of the plurality of first placement grooves and the plurality of second placement grooves along the thickness direction of the main body overlap.

[0011] In one embodiment of the present invention, the first cover plate is provided with a first boss matching with the first placement groove, and the second cover plate is provided with a second boss matching with the second placement groove; the height of the first positioning member is greater than the height of the first boss, and the height of the second positioning member is greater than the height of the second boss.

[0012] The present invention also provides a sample preparation method, using the composite material sample preparation device as described above to prepare a composite material sample, the preparation method comprising: Step S1, obtaining the sample preparation device; Step S2, filling the sample placement unit of the composite material sample preparation device with a material, so that the material extends along the length direction of the main body of the composite material sample preparation device and fills the sample placement unit; Step S3, the cover unit of the composite material sample preparation device is molded and fixed to the main body, and a force is applied to the cover unit so that the cover unit squeezes the material placed in the sample placement unit and maintains the pressure for a specified time; after the temperature drops, the extrusion of the material is stopped, and the composite material sample preparation device is post-cured; Step S4, after the composite material sample preparation device is cooled to room temperature, the cover unit is removed, the material is demoulded from the sample placement unit, and the material is polished to remove burrs to obtain a composite material sample.

[0013] In one embodiment of the present invention, in step S2, the method for filling the material into the sample placement unit includes: Step S21, subjecting the material to a resin-impregnated process to form the material after the resin-impregnation process; Step S22, fix the composite material sample preparation device to the winding machine through the clamping unit, adjust the position of the winding machine so that the material corresponds to one of the placement slots of the sample placement unit, rotate the main body at a specified speed, so that the material is spread into the placement slot along the extension direction of the placement slot, rotate the main body 180°, and then spread the material into the placement slot on the opposite side, continue to rotate the main body until the number of material layers in the placement slot reaches the specified number of layers, cut the material, move the material to another placement slot, and repeat the above operation until each of the placement slots is filled with the material.

[0014] In one embodiment of the present invention, in step S3, the method of extruding the material includes placing the sample preparation device on a molding machine, and applying pressure toward the main body to the first cover plate and the second cover plate of the cover plate unit through the molding machine, so that the first cover plate presses the first surface of the main body, and the second cover plate presses the second surface of the main body.

[0015] In one embodiment of the present invention, in step S3, a pressure-maintaining operation is performed at the resin curing temperature.

[0016] The above technical solution of the present invention has the following advantages compared with the prior art: A composite material sample preparation device described in the present invention is provided with a main body, a sample placement unit and a cover unit, wherein the main body has a first surface and a second surface relative to each other, the sample placement unit includes placement grooves respectively arranged on the first surface and the second surface, the placement grooves are used to fill fiber yarns, and the cover unit includes a first cover and a second cover, the first cover and the second cover can cooperate with the main body for mold closing, so that after the preparation process, the fiber yarns filled in the placement grooves form a test sample. When preparing the test sample, firstly, a directional fiber bundle arrangement is formed in the placement groove of the sample placement unit by using a winding process; secondly, the cover unit and the main body are molded, and the molded cover unit and the main body are placed in a molding machine for heating, pressurization and pressure maintenance for a period of time; after the cover unit and the main body are cooled to room temperature, the sample is taken out to obtain a test sample. In the above manner, the obtained composite material sample meets the preparation requirements of the test sample, and can be used for theoretical verification of the mechanical properties of the product design. Compared with traditional methods such as manual paving and autoclave molding, the composite material sample preparation device of the present invention can be processed and molded without other auxiliary materials, such as vacuum bags, breathable films, sealants, etc., and the obtained test samples do not need to go through complex processes such as cutting, and can be used for testing after removing burrs. The utilization rate of the fiber yarn used to prepare the test samples is also high, which can effectively save raw materials and costs. In addition, by adjusting the process parameters such as the number of winding layers and the pressure of the molding machine, the size and fiber volume content of the test sample can be conveniently adjusted. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0018] Figure 1 It is an exploded view from the first perspective of the overall structure of the preferred embodiment of the present invention.

[0019] Figure 2 yes Figure 1 A partial enlarged view of .

[0020] Figure 3 It is a schematic diagram of an exploded view from a second perspective of the overall structure of a preferred embodiment of the present invention.

[0021] Figure 4 It is a schematic diagram of the overall structural body and the cover plate unit in the mold-clamping state according to the preferred embodiment of the present invention.

[0022] Explanation of the reference numerals in the specification: 1. main body; 101. first positioning groove; 102. second positioning groove; 11. first surface; 110. first placement groove; 12. second surface; 120. second placement groove; 2. placement groove; 201. winding fillet; 202. groove entry fillet; 31. first cover plate; 311. first boss; 310. first positioning member; 32. second cover plate; 320. second positioning member; 321. second boss; 40. clamping column. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0024] Since high-performance carbon fiber prepreg is difficult to obtain, the present invention proposes a process method for preparing mechanical test specimens by combining high-performance carbon fiber with a winding process, including a preparation device and a preparation method. Embodiment 1

[0025] Reference Figure 1 As shown, the present invention discloses a composite material sample preparation device for preparing test samples of carbon fiber composite materials. The composite material sample preparation device includes a main body 1, and the main body 1 has a first surface 11 and a second surface 12 along the thickness direction. The first surface 11 and the second surface 12 are parallel to each other.

[0026] The composite material sample preparation device also includes a sample placement unit, which includes a placement groove 2 respectively arranged on the first surface 11 and the second surface 12, and the placement groove 2 extends along the length direction of the main body 1. The shape and size of the placement groove 2 are set to match the test sample, and the placement groove 2 is relatively arranged along the thickness direction of the main body 1.

[0027] It should be noted that, when preparing the sample, the placement slot 2 is used to fill the fiber yarn, and the cross-sectional shape of the placement slot 2 is the same as the size of the test sample. In order to facilitate demoulding, the cross-sectional shape of the placement slot 2 is set to be rectangular. In detail, in order to avoid the fiber yarn overlapping or pressing down, resulting in uneven distribution or internal bending of the fiber yarn, the slot width of the placement slot 2 is the same as the width of the fiber yarn to be filled.

[0028] Of course, in different implementations, the number of the placement slots 2 can be adjusted according to needs, and the placement slots 2 located on the first surface 11 correspond to the placement slots 2 located on the second surface 12 one by one.

[0029] The composite material sample preparation device also includes a cover plate unit, which includes a first cover plate 31 and a second cover plate 32. The first cover plate 31 and the second cover plate 32 are independently arranged from the main body 1. When working, the first cover plate 31 and the second cover plate 32 can cooperate with the main body 1 to prepare the test sample.

[0030] Specifically, the first cover plate 31 is used to contact with the first surface 11 to press the first surface 11, and the structure of the first cover plate 31 facing the main body 1 is adapted to the main body 1; the second cover plate 32 is in contact with the second surface 12 to press the second surface 12, and the structure of the second cover plate 32 facing the main body 1 is adapted to the main body 1. Such an arrangement can facilitate the mold closing of the cover plate unit and the main body 1.

[0031] It can be known that the composite material sample preparation device to be protected by the present invention is provided with a main body, a sample placement unit and a cover unit, wherein the main body has a first surface and a second surface relative to each other, the sample placement unit includes placement grooves respectively arranged on the first surface and the second surface, the placement grooves are used to fill fiber yarns, and the cover unit includes a first cover and a second cover, the first cover and the second cover can cooperate with the main body for mold closing, so that after the preparation process, the fiber yarns filled in the placement grooves form test samples. When preparing the test sample, firstly, a directional fiber bundle arrangement is formed in the placement groove of the sample placement unit by using a winding process; secondly, the cover unit and the main body are molded, and the cover unit and the main body after the mold closing are placed in a molding machine for heating, pressurization and pressure maintenance for a period of time; after the cover unit and the main body are cooled to room temperature, the sample is taken out to obtain a test sample. In the above manner, the obtained composite material sample meets the preparation requirements of the test sample, and can be used for theoretical verification of the mechanical properties of the product design. Compared with traditional methods such as manual paving and autoclave molding, the composite material sample preparation device of the present invention can be processed and molded without other auxiliary materials, such as vacuum bags, breathable films, sealants, etc., and the obtained test samples do not need to go through complex processes such as cutting, and can be used for testing after removing burrs. The utilization rate of the fiber yarn used to prepare the test samples is also high, which can effectively save raw materials and costs. In addition, by adjusting the process parameters such as the number of winding layers and the pressure of the molding machine, the size and fiber volume content of the test sample can be conveniently adjusted.

[0032] Since the fiber yarn needs to be wound in the placement groove 2 during the process of winding the fiber yarn using the winding machine, in order to avoid the fiber yarn from breaking during the winding process, the groove edge of the placement groove 2 is provided with a winding fillet 201, thereby playing a role in guiding and buffering the fiber yarn.

[0033] In order to ensure that the fiber yarn can completely fall into the placement groove 2 during the winding process, the groove bottom of the placement groove 2 is provided with groove entry fillets 202 at both end edges along the length direction of the main body 1.

[0034] In order to facilitate the installation of the main body 1 on the winding machine, the composite material sample preparation device also includes a clamping unit, which includes clamping columns 40 relatively arranged on both sides of the main body 1, and the axial direction of the clamping column 40 is perpendicular to the length direction of the main body 1. The clamping column 40 is used to be assembled to the winding machine. With this arrangement, under the drive of the winding machine, the main body 1 can rotate around the axial direction of the clamping column 40.

[0035] As a preferred embodiment, mounting holes are symmetrically opened on both sides of the main body 1, and the mounting holes are located in the middle of the side of the main body 1. The clamping column 40 is assembled in the mounting hole, and the clamping column 40 and the mounting hole are interference fit.

[0036] In order to facilitate accurate positioning between the main body 1 and the cover unit during the mold closing process, the composite material sample preparation device also includes a positioning mechanism. Specifically, a first positioning member 310 is provided on the side of the first cover 31 that contacts the main body 1, and correspondingly, a first positioning groove 101 that matches the first positioning member 310 is provided on the main body 1. A second positioning member 320 is provided on the side of the second cover 32 that contacts the main body 1, and correspondingly, a second positioning groove 102 that matches the second positioning member 320 is provided on the main body 1. In this way, the first cover 31 and the main body 1 can be positioned by the cooperation between the first positioning member 310 and the first positioning groove 101; the second cover 32 and the main body 1 can be positioned by the cooperation between the second positioning member 320 and the second positioning groove 102.

[0037] As a preferred embodiment, the first positioning member 310 includes but is not limited to a guide post. The second positioning member 320 includes but is not limited to a guide post.

[0038] Of course, in some other embodiments, the positioning mechanism may be arranged in such a manner that a first positioning protrusion is arranged on the first surface 11 of the main body 1, and a first positioning recess matched with the first positioning protrusion is arranged on the first cover plate 31, so as to achieve positioning between the first cover plate 31 and the main body 1; and a second positioning protrusion is arranged on the second surface 12 of the main body 1, and a second positioning recess matched with the second positioning protrusion is arranged on the second cover plate 32, so as to achieve positioning between the second cover plate 32 and the main body 1.

[0039] As a preferred embodiment, the sample placement unit includes a plurality of first placement grooves 110 arranged on the first surface 11, and a plurality of second placement grooves 120 arranged on the second surface 12, and the projections of the plurality of first placement grooves 110 and the plurality of second placement grooves 120 along the thickness direction of the main body overlap.

[0040] In order to achieve accurate mold fitting of the cover plate unit and the main body 1 , the first cover plate 31 is provided with a first boss 311 matching with the first placement groove 110 , and the second cover plate 32 is provided with a second boss 321 matching with the second placement groove 120 .

[0041] Furthermore, in order to ensure that the pressing force on the fiber yarn meets the requirement when the mold is closed, the height of the first positioning member 310 is greater than the height of the first boss 311 , and the height of the second positioning member 320 is greater than the height of the second boss 321 .

[0042] It should be noted that the pressure of the cover unit on the sample in the placement groove 2 should be applied evenly. If necessary, a gasket can be added between the cover unit and the main body 1 to achieve the purpose of pressure control and leveling. Embodiment 2

[0043] The present invention also discloses a sample preparation method, which uses the composite material sample preparation device as described in the first embodiment to prepare a composite material sample, and the preparation method comprises: Step S1, obtaining the sample preparation device; Step S2, filling the sample placement unit of the composite material sample preparation device with a material, so that the material extends along the length direction of the main body 1 of the composite material sample preparation device and fills the sample placement unit; Step S3, the cover unit of the composite material sample preparation device is molded and fixed with the main body 1, and a force is applied to the cover unit so that the cover unit squeezes the material placed in the sample placement unit and maintains the pressure for a specified time; after the temperature drops, the extrusion of the material is stopped, and the composite material sample preparation device is post-cured; Step S4, after the composite material sample preparation device is cooled to room temperature, the cover unit is removed, the material is demoulded from the sample placement unit, and the material is polished to remove burrs to obtain a composite material sample.

[0044] It should be noted that, in this embodiment, the material includes but is not limited to fiber yarn.

[0045] Specifically, in step S1, the sample preparation device can be manufactured by a processing method, and a release agent can be coated on the surface of the main body 1 to facilitate demolding later. The number of winding layers and the molding machine process parameters can be set in advance based on the basic parameters of the selected material.

[0046] As a preferred embodiment, in the step S2, the method for filling the material into the sample placement unit includes: Step S21, subjecting the material to a resin-impregnated process, thereby forming the material after the resin-impregnation process; Step S22, fix the composite material sample preparation device to the winding machine through the clamping unit, adjust the position of the winding machine so that the material corresponds to one of the placement slots 2 of the sample placement unit, rotate the main body 1 at a specified speed, so that the material is spread into the placement slot 2 along the extension direction of the placement slot 2, rotate the main body 180°, and then spread the material into the placement slot 2 on the opposite side, continue to rotate the main body 1 until the number of material layers in the placement slot 2 reaches the specified number of layers, cut the material, move the material to another placement slot, and repeat the above operation until each of the placement slots is filled with the material.

[0047] It should be noted that, in the step S22, the winding machine is controlled to rotate the main body 1 at a speed of 1-30 rpm.

[0048] It can be known that the composite material sample preparation method of the present invention applies tension to the fiber yarn by cooperating with the winding process to simulate the effect of traction on the fiber yarn, and simulates the state of single orientation of the fiber yarn by limiting the placement of the groove 2 on the main body 1 and the in-situ winding process; and controls the size and fiber volume fraction of the final sample by controlling the number of winding layers and the pressure of the molding machine. In the above manner, the obtained composite material sample meets the preparation requirements of the test sample and can be used for theoretical verification of the mechanical properties of the product design.

[0049] In detail, in step S3, the method of squeezing the material includes placing the sample preparation device on a molding machine, and applying pressure toward the main body 1 to the first cover plate 31 and the second cover plate 32 of the cover plate unit through the molding machine, so that the first cover plate 31 presses the first surface 11 of the main body 1, and the second cover plate 32 presses the second surface 12 of the main body 1. In this way, the first boss 311 on the first cover plate 31 can be driven to produce a certain squeezing effect on the fiber yarn in the sample slot 2, and correspondingly, the second boss 321 on the second cover plate 32 can also be driven to produce a certain squeezing effect on the fiber yarn in the sample slot 2.

[0050] It should be noted that the winding speed should be controlled during the winding process to avoid product fiber damage or performance degradation caused by yarn hanging, yarn scraping, yarn deviation and other problems.

[0051] In detail, in step S3, the pressure holding operation is performed at the resin curing temperature.

[0052] The preparation method of the present invention is described below by taking a specific embodiment as an example: It is necessary to produce composite material long rods with a cross-section of 5mm*3mm rectangle and a fiber volume fraction of 60%.

[0053] The corresponding sample preparation device is designed and produced according to the actual situation. T800 is selected as the carbon fiber raw material. The width of the placement groove 2 in the main body 1 is designed to be 5 mm, and the depth is 5 mm. The width of the first boss 311 located on the first cover plate 31 and the second boss 321 located on the second cover plate 32 are 4.9 mm, and the depth is 5 mm.

[0054] First, preliminary preparations are made, the sample preparation device is obtained by a processing method, and a release agent is applied to the surface of the main body 1. According to the fiber parameters, the number of winding layers is calculated to be 19 layers, and the molding machine needs to heat and maintain pressure for 3 hours at a pressure of 10 tons.

[0055] Next, in the winding process step, the main body 1 is fixed on the winding machine, and the position of the winding machine is adjusted so that the yarn corresponds to one of the placement slots 2. The main body 1 is slowly rotated at a constant speed so that the yarn after being dipped in glue is laid into the placement slot 2 along the direction of the placement slot 2. When the mold is rotated 180°, the yarn is laid into the placement slot 2 on the opposite side. After the cycle reaches the specified number of layers, the yarn is cut, the yarn position is moved to the next placement slot, and the above operation is repeated. After all the winding work is completed, the main body is removed from the equipment, and the first cover plate and the second cover plate are molded and fixed along the thickness direction of the main body 1.

[0056] Furthermore, in the curing and post-curing process steps, a molding machine is used to apply 10 tons of pressure to the outer sides of the first cover plate 31 and the second cover plate 32, so that the first boss 311 on the first cover plate 31 compresses the fibers in the placement groove 2 to a thickness of 3 mm, and the second boss 321 on the second cover plate 32 compresses the fibers in the placement groove 2 to a thickness of 3 mm, and the pressure is maintained at 130°C for 2 hours.

[0057] Next, the mold was taken out after cooling down, and the whole was placed in an oven at 140° C. for 3 hours for post-curing treatment.

[0058] Finally, the sample was cooled to room temperature, demolded, and burrs were removed by grinding to obtain the desired sample.

[0059] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "setting" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0061] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A composite material sample preparation device for preparing a test sample of a carbon fiber composite material, characterized in that: include, A main body having a first surface and a second surface along a thickness direction; A sample placement unit, comprising placement grooves respectively arranged on the first surface and the second surface, the placement grooves extending along the length direction of the main body, the placement grooves being arranged to match the test sample, and the placement grooves being arranged opposite to each other along the thickness direction of the main body; The cover plate unit comprises a first cover plate and a second cover plate, wherein the first cover plate contacts the first surface to press the first surface, and the side of the first cover plate facing the main body is adapted to the main body; the second cover plate contacts the second surface to press the second surface, and the side of the second cover plate facing the main body is adapted to the main body.

2. A composite material sample preparation device according to claim 1, characterized in that: The slot edge of the placement slot is provided with a winding fillet; the slot bottom of the placement slot is provided with slot entry fillets at both end edges along the length direction of the main body.

3. A composite material sample preparation device according to claim 1, characterized in that: It also includes a clamping unit, which includes clamping columns relatively arranged on both sides of the main body, the axial direction of the clamping column is perpendicular to the length direction of the main body, and the clamping column is used to be assembled to the winding machine.

4. A composite material sample preparation device according to claim 1, characterized in that: A first positioning piece is provided on the side of the first cover plate that contacts the main body, and a first positioning groove matching the first positioning piece is provided on the main body; a second positioning piece is provided on the side of the second cover plate that contacts the main body, and a second positioning groove matching the second positioning piece is provided on the main body.

5. A composite material sample preparation device according to claim 4, characterized in that: The sample placement unit includes a plurality of first placement grooves arranged on the first surface, and a plurality of second placement grooves arranged on the second surface, and projections of the plurality of first placement grooves and the plurality of second placement grooves along the thickness direction of the main body overlap.

6. A composite material sample preparation device according to claim 5, characterized in that: The first cover plate is provided with a first boss matched with the first placement groove, and the second cover plate is provided with a second boss matched with the second placement groove; the height of the first positioning member is greater than the height of the first boss, and the height of the second positioning member is greater than the height of the second boss.

7. A sample preparation method, characterized in that: A composite material sample is prepared using the composite material sample preparation device as described in any one of claims 1 to 6, the preparation method comprising: Step S1, obtaining the sample preparation device; Step S2, filling the sample placement unit of the composite material sample preparation device with a material, so that the material extends along the length direction of the main body of the composite material sample preparation device and fills the sample placement unit; Step S3, the cover unit of the composite material sample preparation device is molded and fixed to the main body, and a force is applied to the cover unit so that the cover unit squeezes the material placed in the sample placement unit, and the pressure is maintained for a specified time; After the temperature drops, the extrusion of the material is stopped, and the composite material sample preparation device is subjected to a post-curing treatment; Step S4, after the composite material sample preparation device is cooled to room temperature, the cover unit is removed, the material is demoulded from the sample placement unit, and the material is polished to remove burrs to obtain a composite material sample.

8. A sample preparation method according to claim 7, characterized in that: In the step S2, the method for filling the material into the sample placement unit includes: Step S21, subjecting the material to a resin-impregnated process to form the material after the resin-impregnation process; Step S22, fix the composite material sample preparation device to the winding machine through the clamping unit, adjust the position of the winding machine so that the material corresponds to one of the placement slots of the sample placement unit, rotate the main body at a specified speed, so that the material is spread into the placement slot along the extension direction of the placement slot, rotate the main body 180°, and then spread the material into the placement slot on the opposite side, continue to rotate the main body until the number of material layers in the placement slot reaches the specified number of layers, cut the material, move the material to another placement slot, and repeat the above operation until each of the placement slots is filled with the material.

9. A sample preparation method according to claim 7, characterized in that: In step S3, the method for extruding the material includes placing the sample preparation device on a molding machine, and applying pressure toward the main body to the first cover plate and the second cover plate of the cover plate unit through the molding machine, so that the first cover plate presses the first surface of the main body, and the second cover plate presses the second surface of the main body.

10. A sample preparation method according to claim 7, characterized in that: In the step S3, a pressure maintaining operation is performed at the resin curing temperature.

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