Composite material grating and preparation method thereof

Abstract

The invention provides a preparation method of a composite material grid. The preparation method comprises the following steps: respectively inserting a plurality of hole columns arranged in multiple rows and multiple columns into a plurality of hole grids of a tool hole grid area; the tool is provided with a hole grid area and a frame area located on the periphery of the hole grid area. Paving at least one prepreg layer on the frame area; sequentially paving each first prepreg strip in the plurality of first prepreg strips between the plurality of hole columns in two adjacent rows, and sequentially paving each second prepreg strip in the plurality of second prepreg strips between the plurality of hole columns in two adjacent columns, so as to obtain a grating middleware; curing the grid middleware under the conditions of high temperature and high pressure; the cured grid middleware is separated from the tool, and the composite material grid with a plurality of grid holes is obtained; and the shapes of the plurality of grating holes are determined by the shapes of the plurality of hole columns respectively. The technical problems of material fatigue, strength failure, environmental corrosion and the like in the use process of the grating in the prior art can be at least solved.

Description

Technical Field

[0001] The present invention relates to the technical field of grilles, and more particularly, to a composite grille and a preparation method thereof. Background Art

[0002] So far, the intake and exhaust grilles actually applied to aircraft mainly use metal materials such as aluminum alloy, magnesium alloy, titanium alloy, and high-strength steel.

[0003] Compared with metal materials, carbon fiber composite materials, as organic non-metallic materials, have the advantages of light weight, high strength, good fatigue resistance, corrosion resistance, flexible design, strong shock absorption performance, low coefficient of thermal expansion, and can be integrally formed. Due to the advantages that other materials do not have and the application prospects, carbon fiber composite materials have received great attention from the industrial community.

[0004] When the mainstream metal materials are machined by a machine tool to obtain the shape, size, and hole pattern adapted to the aircraft intake and exhaust ports, during use, when geometric discontinuities such as holes or notches appear in the metal, fatigue cracks are likely to be induced, or surface cracking may occur due to factors such as processing and environment, resulting in the strength failure of the part. Summary of the Invention

[0005] The composite grille and the preparation method provided by the embodiments of the present invention can at least solve the technical problems such as material fatigue, strength failure, and environmental corrosion that occur during the use of the grille in the prior art.

[0006] The embodiments of the present invention provide a preparation method of a composite grille, which includes:

[0007] Inserting a plurality of hole columns arranged in multiple rows and columns into a plurality of hole patterns of a tooling; wherein, the plurality of hole patterns are also arranged in multiple rows and columns, the tooling has a hole pattern area and a frame area located outside the hole pattern area, and the plurality of hole patterns are opened in the hole pattern area;

[0008] Laying at least one prepreg layer on the frame area;

[0009] Laying each of a plurality of first prepreg strips in sequence between the plurality of hole columns in adjacent two rows, and laying each of a plurality of second prepreg strips in sequence between the plurality of hole columns in adjacent two columns to obtain a grille intermediate;

[0010] Curing the grille intermediate under high temperature and high pressure conditions;

[0011] Detaching the cured grille intermediate from the tooling to obtain the composite grille having a plurality of grille holes; the shapes of the plurality of hole columns respectively determine the shapes of the plurality of grille holes.

[0012] Preferably, the fibers in the at least one prepreg layer, each first prepreg strip, and each second prepreg strip are carbon fibers or aramid fibers.

[0013] Preferably, the widths of the plurality of first prepreg strips are equal, and the widths of the plurality of second prepreg strips are equal; the fibers in the plurality of first prepreg strips and the plurality of second prepreg strips are continuous fibers.

[0014] Preferably, the plurality of first prepreg strips all extend to the border area, and the plurality of second prepreg strips also all extend to the border area.

[0015] Preferably, the pore walls of the plurality of grid holes formed by the intersection of the plurality of first prepreg strips and the plurality of second prepreg strips are all inclined; or

[0016] the pore walls of the plurality of grid holes formed by the intersection of the plurality of first prepreg strips and the plurality of second prepreg strips are all small pore walls.

[0017] Preferably, the prepregs in the at least one prepreg layer, each first prepreg strip, and each second prepreg strip are obtained by making a wave-absorbing material containing resin and wave-absorbing agent into a film and thermocompression-infiltrating the film with fibers; or

[0018] the prepregs in the at least one prepreg layer, each first prepreg strip, and each second prepreg strip are obtained by making a high-temperature-resistant resin into a film and thermocompression-infiltrating the film with fibers.

[0019] Preferably, the wave-absorbing agent is carbonyl iron powder or ferrite;

[0020] or the high-temperature-resistant resin is bismaleimide resin or polyimide resin.

[0021] Preferably, the curing of the grid intermediate under high temperature and high pressure conditions is carried out in an autoclave; the curing of the grid intermediate under high temperature and high pressure conditions includes: first raising the temperature of the grid intermediate from room temperature to 125 - 135 °C, with a temperature rising time of 1 - 2 hours; then, raising the temperature of the grid intermediate from 125 - 135 °C to 145 - 155 °C, with a temperature rising time of 1 - 2 hours; then, raising the temperature of the grid intermediate from 145 - 155 °C to 175 - 185 °C, with a temperature rising time of 3 - 4 hours; finally, lowering the temperature of the grid intermediate from 175 - 185 °C to room temperature, with a temperature dropping time of 4 - 5 hours.

[0022] Preferably, the high pressure condition is 0.5 MPa - 1 MPa; preferably, the high pressure condition is 0.7 MPa.

[0023] Preferably, the fibers in the plurality of first prepreg strips and the plurality of second prepreg strips are continuous fibers.

[0024] The beneficial effects of the present invention are as follows:

[0025] The composite material grid in the embodiment of the present invention can use prepreg cut into the shape of an outer frame and continuous fiber strips for making grid holes (i.e., a plurality of first prepreg strips and a plurality of second prepreg strips), which can solve the problems of material fatigue and environmental corrosion during use, and obtain a longer service life and a wider application scenario. When other functional prepregs (such as high-temperature-resistant prepregs, wave-absorbing prepregs, etc.) are used for co-curing in the pneumatic surface layer, more durable functional effects can be obtained while ensuring strength. The present invention enhances the durability of the composite material grid during use, and increases the methods for endowing special functions and the stability of special functions (such as composite material grids with high-temperature-resistant functions and composite material grids with wave-absorbing functions). Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is a flowchart of the preparation method of the composite material grid provided by the embodiment of the present invention.

[0028] Figure 2 For Figure 1 A schematic diagram of the composite material grid obtained by the shown preparation method.

[0029] Figure 3 It is a schematic diagram of an inclined-hole composite material grid provided by another embodiment of the present invention.

[0030] Figure 4 It is a schematic diagram of a small-hole-wall composite material grid provided by another embodiment of the present invention. Detailed Embodiments

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0032] As Figure 1 And Figure 2As shown, the method for preparing the composite material grid includes:

[0033] Inserting multiple hole columns arranged in multiple rows and columns into multiple hole cells of tooling 1 respectively; wherein, the multiple hole cells are also arranged in multiple rows and columns, the tooling has a hole cell area and a frame area located outside the hole cell area, and the multiple hole cells are opened in the hole cell area;

[0034] Laying at least one prepreg layer 2 (i.e., one or more prepreg layers 2) on the frame area;

[0035] Laying each first prepreg strip 3 among multiple first prepreg strips 3 successively between multiple hole columns in adjacent rows, and laying each second prepreg strip 4 among multiple second prepreg strips 4 successively between multiple hole columns in adjacent columns to obtain a grid intermediate;

[0036] Curing the grid intermediate under high temperature and high pressure conditions;

[0037] Detaching the cured grid intermediate from the tooling 1 to obtain the composite material grid 5 with multiple grid holes; the shapes of the multiple hole columns respectively determine the shapes of the multiple grid holes.

[0038] In the embodiment of the present invention, the fibers in the at least one prepreg layer, each first prepreg strip, and each second prepreg strip are all carbon fibers or aramid fibers.

[0039] In the embodiment of the present invention, the widths of the multiple first prepreg strips are all equal, and the widths of the multiple second prepreg strips are all equal; the fibers in the multiple first prepreg strips and the multiple second prepreg strips are all continuous fibers.

[0040] In the embodiment of the present invention, the multiple first prepreg strips all extend to the frame area, and the multiple second prepreg strips also all extend to the frame area.

[0041] In the embodiment of the present invention, the pore walls of the multiple grid holes formed by the intersection of the multiple first prepreg strips and the multiple second prepreg strips are all inclined, so that the multiple grid holes have a certain guiding property for the fluid flowing through the composite material grid.

[0042] Or, in an optional other embodiment, the pore walls of the multiple grid holes formed by the intersection of the multiple first prepreg strips and the multiple second prepreg strips are all small pore walls.

[0043] As a non-limiting explanatory note, the thickness of the pore wall of each grid hole refers to the width of the first prepreg strip or the second prepreg strip.

[0044] In the embodiments of the present invention, the widths of the plurality of first prepreg strips are all 2 - 3 mm, and the widths of the plurality of second prepreg strips are all 2 - 3 mm; the thickness of the pore wall of each grid hole is 2 - 3 mm, that is, the pore walls of the plurality of grid holes are all normal pore walls.

[0045] Optionally, in other embodiments of the present invention, by way of non-limiting illustration, the widths of the plurality of first prepreg strips are all 1 mm, and the widths of the plurality of second prepreg strips are all 1 mm; the thickness of the pore wall of each grid hole is 1 mm, that is, the pore walls of the plurality of grid holes are all small pore walls.

[0046] In the embodiments of the present invention, the prepreg in the at least one prepreg layer, each first prepreg strip, and each second prepreg strip is obtained by making a wave-absorbing material containing resin and a wave-absorbing agent into a film and thermally pressing and infiltrating the film with fibers; or

[0047] the prepreg in the at least one prepreg layer, each first prepreg strip, and each second prepreg strip is obtained by making a high-temperature-resistant resin into a film and thermally pressing and infiltrating the film with fibers.

[0048] In the embodiments of the present invention, the wave-absorbing agent is a common wave-absorbing agent such as carbonyl iron powder or ferrite.

[0049] Or the high-temperature-resistant resin is bismaleimide resin or polyimide resin.

[0050] In the embodiments of the present invention, the curing of the grid intermediate under high temperature and high pressure conditions is carried out in an autoclave; the curing of the grid intermediate under high temperature and high pressure conditions includes: first, raising the temperature of the grid intermediate from room temperature (e.g., 25°C) to 125 - 135°C, with the temperature rising time being 1 - 2 hours; subsequently, raising the temperature of the grid intermediate from 125 - 135°C to 145 - 155°C, with the temperature rising time being 1 - 2 hours; then, raising the temperature of the grid intermediate from 145 - 155°C to 175 - 185°C, with the temperature rising time being 3 - 4 hours; finally, lowering the temperature of the grid intermediate from 175 - 185°C to room temperature, with the temperature falling time being 4 - 5 hours.

[0051] Preferably, the curing of the grid intermediate under high temperature and high pressure conditions includes: first, raising the temperature of the grid intermediate from room temperature (e.g., 25°C) to 130°C, with the temperature rising time being 1 - 2 hours; subsequently, raising the temperature of the grid intermediate from 130°C to 150°C, with the temperature rising time being 1 - 2 hours; then, raising the temperature of the grid intermediate from 150°C to 180°C, with the temperature rising time being 3 - 4 hours; finally, lowering the temperature of the grid intermediate from 180°C to room temperature, with the temperature falling time being 4 - 5 hours.

[0052] Specifically, the high pressure condition is 0.5 MPa to 1 MPa; preferably, the high pressure condition is 0.7 MPa.

[0053] In an embodiment of the present invention, the fibers in the multiple first prepreg strips and the multiple second prepreg strips are all continuous fibers; thereby, the strength of the pore area of ​​the composite material grid is guaranteed to the greatest extent. At the same time, different prepregs are added to this area for co-curing, so that other properties (such as wave absorption, high temperature resistance (that is, a composite material grid with high temperature resistance function, a composite material grid with wave absorption function) etc.) can be achieved while ensuring strength.

[0054] The embodiment of the present invention improves the material selection of the composite material grid. Since the material process is changed after the improvement, the composite material grid obtains better performance, thereby producing the effect of a multifunctional grid (for example, a composite material grid with high temperature resistance function, a composite material grid with wave absorption function).

[0055] Example 1

[0056] Preparation of composite grid:

[0057] 1) inserting a hole column that matches the size and shape of the hole into the hole of the tooling to constrain the position of the fiber strip; the tooling has a hole area and a frame area located outside the hole area, and the hole area is provided with the plurality of holes;

[0058] 2) laying at least one prepreg layer in an area outside the grid on the specially treated tool as a border area (that is, laying at least one prepreg layer in the border area);

[0059] 3) laying a plurality of first carbon fiber prepreg strips and a plurality of second carbon fiber prepreg strips cut into appropriate widths in two directions according to the positions of the holes and columns and extending them to the frame area to obtain a grid intermediate piece;

[0060] 4) Put the grid middle piece into the autoclave for high temperature and high pressure curing;

[0061] 5) The cured grille is separated from the tooling, and the pocket surface is polished to obtain a composite grille with complete pores.

[0062] Example 2

[0063] The specific implementation method is similar to that of Example 1, except that the hole walls of the multiple grid holes formed by the intersection of the multiple first prepreg strips and the multiple second prepreg strips of the inclined hole composite grid structure are all inclined, so that the multiple grid holes have a certain degree of guidance for the fluid flowing through the composite grid; Figure 3 The oblique hole composite grille shown.

[0064] Example 3

[0065] The specific implementation method is similar to that of Embodiment 1. The difference is that the pore wall composite material grid structure, that is, the pore walls of multiple grid holes formed by the intersection of multiple first prepreg strips and multiple second prepreg strips are all small pore walls, as Figure 4 shown in the small pore wall composite material grid.

[0066] The composite material grid described in the embodiment of the present invention can be a carbon fiber reinforced resin matrix composite material grid. The composite material grid is prepared by using prepreg paving and autoclave curing process. The pore cells of the prepared composite material grid are all composed of continuous fibers and extend to the border area, ensuring that the composite material grid still has corresponding strength support under strong air flow impact. At the same time, the co-curing of the additional functional material and the load-bearing material in the pore cell area enables the composite material grid to have other functions (such as: wave absorption, temperature resistance, etc.) while ensuring strength.

[0067] The composite material grid described in the embodiment of the present invention can be a carbon fiber reinforced resin matrix composite material grid, which can replace the metal grid at the air inlet and outlet of the aircraft; it can be manufactured according to the interface conditions of the air inlet and outlet to ensure reliable strength and stable performance.

[0068] The composite material grid described in the embodiment of the present invention can use carbon fiber prepreg cut into the shape of the outer frame and continuous fiber strips for making grid holes to solve the problems of material fatigue and environmental corrosion during use, and obtain a longer service life and a wider application scenario. When other functional prepregs (such as high-temperature resistant prepregs, wave absorption prepregs, etc.) are used for co-curing in the pneumatic surface layer, more durable functional effects can be obtained while ensuring strength. The present invention enhances the durability of the composite material grid during use and increases the method of endowing special functions and the stability of special functions (such as composite material grids with high-temperature resistant functions, composite material grids with wave absorption functions).

[0069] The composite material grid has the following advantages:

[0070] 1. The preparation process of the composite material grid is simple. Using prepreg paving and curing under high temperature and high pressure helps to ensure that the strength meets the standard.

[0071] 2. Lightweight, high strength, no metal fatigue, corrosion resistant, and at the same time, more stable special properties can be endued.

[0072] 3. High surface accuracy. After being prepared into a composite material grid, the surface accuracy is ensured by controlling the surface shape with a machine tool.

[0073] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a composite material grid, characterized in that: include: Inserting a plurality of hole columns arranged in a plurality of rows and columns into a plurality of holes of a tool respectively; wherein the plurality of holes are also arranged in a plurality of rows and columns, the tool comprises a hole area and a frame area located outside the hole area, and the hole area is provided with the plurality of holes; Laying at least one prepreg layer in the border area; Laying each of the plurality of first prepreg strips in sequence between the plurality of hole columns in two adjacent rows, and laying each of the plurality of second prepreg strips in sequence between the plurality of hole columns in two adjacent columns, so as to obtain a grid intermediate member; Curing the grid intermediate piece under high temperature and high pressure conditions; The solidified grid intermediate piece is separated from the tooling to obtain the composite material grid having a plurality of grid holes; the shapes of the plurality of hole columns respectively determine the shapes of the plurality of grid holes.

2. The preparation method according to claim 1, characterized in that: The fibers in the at least one prepreg layer, each first prepreg strip and each second prepreg strip are all carbon fibers or aramid fibers.

3. The preparation method according to claim 1, characterized in that: The widths of the plurality of first prepreg strips are all equal, and the widths of the plurality of second prepreg strips are all equal; and the fibers in the plurality of first prepreg strips and the plurality of second prepreg strips are all continuous fibers.

4. The preparation method according to claim 1, characterized in that: The plurality of first prepreg strips all extend to the frame area, and the plurality of second prepreg strips also all extend to the frame area.

5. The preparation method according to claim 1, characterized in that: The hole walls of the plurality of grid holes formed by the intersection of the plurality of first prepreg strips and the plurality of second prepreg strips are all inclined; or The hole walls of the plurality of grid holes formed by the intersection of the plurality of first prepreg strips and the plurality of second prepreg strips are all small hole walls.

6. The drilling auxiliary tool according to claim 1, characterized in that: The prepregs in the at least one prepreg layer, each first prepreg strip and each second prepreg strip are all obtained by forming an absorbing material containing a resin and an absorbent into an adhesive film and hot-pressing and impregnating the adhesive film with fibers; or The prepregs in the at least one prepreg layer, each first prepreg strip and each second prepreg strip are all obtained by making a high temperature resistant resin into an adhesive film and hot pressing and impregnating the adhesive film with fibers.

7. The drilling auxiliary tool according to claim 6, characterized in that: The wave absorbing agent is carbonyl iron powder or ferrite; Alternatively, the high temperature resistant resin is bismaleimide resin or polyimide resin.

8. The drilling auxiliary tool according to claim 1, characterized in that: The grid middle piece is cured under high temperature and high pressure conditions in an autoclave; the curing of the grid middle piece under high temperature and high pressure conditions comprises: firstly, raising the temperature of the grid middle piece from room temperature to 125-135°C for 1-2 hours; then, raising the temperature of the grid middle piece from 125-135°C to 145-155°C for 1-2 hours; then, raising the temperature of the grid middle piece from 145-155°C to 175-185°C for 3-4 hours; finally, lowering the temperature of the grid middle piece from 175-185°C to room temperature for 4-5 hours.

9. The preparation method according to claim 8, characterized in that: The high pressure condition is 0.5 MPa to 1 MPa; preferably, the high pressure condition is 0.7 MPa.

10. A composite material grid, characterized in that: The composite material grid is prepared by the preparation method of the composite material grid as claimed in any one of claims 1 to 9.

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