Method of manufacturing a honeycomb preform and honeycomb preform

Abstract

The application belongs to the technical field of aviation composite material manufacturing, and discloses a honeycomb preform manufacturing method and a honeycomb preform. The honeycomb preform manufacturing method comprises the following steps: S100, laying a bottom layer structure on a preforming tool; S200, laying a honeycomb body on the bottom layer structure and applying pressure to the honeycomb body, so that the honeycomb body is pressed against the bottom layer structure; S300, surrounding the honeycomb body with a blocking protection assembly, the blocking protection assembly is attached to and surrounds the circumferential side of the honeycomb body; and S400, vacuum curing the honeycomb body and the blocking protection assembly. The honeycomb preform manufacturing method can improve the structural strength and integrity of the honeycomb with large thickness and large curvature, reduce defects of the honeycomb, and improve the forming quality.

Description

Technical Field

[0001] This invention relates to the field of aerospace composite material manufacturing technology, and in particular to a method for manufacturing a honeycomb preform and the honeycomb preform itself. Background Technology

[0002] Honeycomb sandwich structures typically consist of a thin skin and a thicker honeycomb core, with the skin covering the outside of the core and the two bonded together. Honeycomb sandwich structures offer advantages such as light weight, high flexural strength and stiffness, strong resistance to instability, fatigue resistance, and good sound absorption, sound insulation, and heat insulation properties. Currently, honeycomb sandwich structures are widely used in load-bearing components of aircraft, including wings, fuselages, tail sections, radomes, floors, and interior trim.

[0003] Depending on the structural strength requirements of different load-bearing components in their service environments, the details of the honeycomb core need to be adaptively designed. For load-bearing components with high bending resistance requirements, the thickness of the honeycomb core usually needs to be increased to rapidly improve the effective load-bearing ratio of the structure while avoiding excessive weight increase. However, in the process design stage, such large-size, high-curvature honeycomb cores present the following manufacturing challenges:

[0004] First, as the thickness of the honeycomb core increases, its bending strength also increases significantly. This makes deformation during the layup process increasingly difficult, leading to a high risk of springback, especially in load-bearing components with large curvatures or complex shapes. Second, with increased honeycomb core thickness, under the pre-set autoclave molding pressure, the pressure-bearing area of ​​the inclined surface of the honeycomb core increases, leading to increased horizontal pressure distribution. This increases the risk of quality defects such as edge slippage and collapse, necessitating additional stabilization treatment. However, stabilization essentially "hardens" the honeycomb core, restricting its free deformation capacity.

[0005] For the stacking process of honeycomb cores with large thickness and size, the traditional processing method, which is to first process the honeycomb into shape and then vacuum compact it to form a curved surface, will make it difficult for the honeycomb to form a long-term and tight fit with the lower skin. This will cause problems such as edge lifting or local delamination during the stacking process, resulting in defects such as edge bridging, weakened adhesion in local areas, and even delamination, causing parts to be scrapped.

[0006] Therefore, there is an urgent need for a method for manufacturing honeycomb preforms and honeycomb preforms, which can replace the honeycomb core inside the honeycomb sandwich structure in the prior art to solve the above problems. Summary of the Invention

[0007] According to one aspect of the present invention, the object is to provide a method for manufacturing a honeycomb preform, which can improve the structural strength and integrity of a honeycomb core with large thickness and large curvature, reduce defects in the honeycomb core, and improve the molding quality.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] Methods for manufacturing cellular preforms include:

[0010] Step S100: Lay the bottom layer structure on the preformed tooling;

[0011] Step S200: Lay the honeycomb body on the bottom layup structure and apply pressure to the honeycomb body so that the honeycomb body presses against the bottom layup structure to form a honeycomb prefabricated component;

[0012] Step S300: A blocking and protective component is provided around the periphery of the cellular body, the blocking and protective component being attached to and surrounding the periphery of the cellular body;

[0013] Step S400: Vacuum encapsulate the honeycomb body and the barrier protection component, and cure the honeycomb preform composed of the bottom layup structure and the honeycomb body.

[0014] As a preferred embodiment of the honeycomb preform manufacturing method provided by the present invention, the bottom layup structure includes a peelable fabric layer, a prepreg fabric layer, and an adhesive film layer; step S100 includes:

[0015] Step S110: Lay a peelable fabric layer on the preformed fixture and vacuum compact it;

[0016] Step S120: Lay the prepreg fabric layer on the peelable fabric layer and vacuum compact it;

[0017] Step S130: Lay an adhesive film layer on the prepreg fabric layer and vacuum compact it.

[0018] As a preferred embodiment of the method for manufacturing cellular preforms provided by the present invention, in steps S110, S120 and S130, the pressure during the vacuum compaction process is not less than 90 kPa.

[0019] As a preferred embodiment of the method for manufacturing cellular preforms provided by the present invention, in steps S110, S120 and S130, the duration of each vacuum compaction is not less than 15 minutes.

[0020] As a preferred embodiment of the method for manufacturing cellular preforms provided by the present invention, in step S300, the upper end face of the blocking and protection component protrudes from the upper end face of the cellular body.

[0021] As a preferred embodiment of the method for manufacturing cellular preforms provided by the present invention, the upper surface of the barrier protection component is 5 mm higher than the upper surface of the cellular body.

[0022] As a preferred embodiment of the honeycomb preform manufacturing method provided by the present invention, step S400 includes:

[0023] Step S410: Apply a vacuum sealing layer to the cell body and the barrier protection component. The vacuum sealing layer consists of an isolation film, a breathable felt, and a vacuum bag sequentially disposed outside the cell body and the barrier protection component.

[0024] Step S420: Vacuum the vacuum bag;

[0025] Step S430: Hot pressing and curing;

[0026] Step S440: Remove the vacuum seal layer.

[0027] As a preferred embodiment of the honeycomb preform manufacturing method provided by the present invention, after step S400, the following steps are performed:

[0028] Step S500: Chamfer the sides of the honeycomb preform and round the edges of the honeycomb preform.

[0029] According to another aspect of the present invention, an object is to provide a cellular preform manufactured using a cellular preform manufacturing method as described in any of the above embodiments.

[0030] As a preferred embodiment of the honeycomb preform provided by the present invention, the honeycomb body is an aramid paper honeycomb.

[0031] The beneficial effects of this invention are:

[0032] The honeycomb preform manufacturing method provided by this invention involves laying a bottom layup structure on a preforming fixture to form an adhesive surface at the bottom of the honeycomb preform, facilitating subsequent manufacturing. By laying the honeycomb body on the bottom layup structure and applying pressure to it, the honeycomb body reliably presses against the bottom layup structure, achieving a preliminary stable adhesion between the honeycomb body and the bottom layup structure, thus forming the honeycomb preform. This improves the connection reliability and structural consistency of the layers within the honeycomb preform. A protective barrier component surrounding the periphery of the honeycomb body enhances its lateral stiffness and prevents the sides of the honeycomb body from collapsing towards the center. By vacuum sealing the honeycomb body and the barrier protection component, and curing the honeycomb preform composed of the bottom layup structure and the honeycomb body, the structural consistency and strength of the honeycomb preform are improved, and the molding quality is enhanced. In this honeycomb preform manufacturing method, each step uses a set of tooling. The preform fabrication, layup and machining are all carried out on a set of tooling, eliminating the need for demolding and repositioning. This reduces the number of processes, improves production efficiency, and reduces equipment investment. Attached Figure Description

[0033] Figure 1 This is a flowchart of the method for manufacturing cellular preforms provided in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of a honeycomb prefabricated component provided in an embodiment of the present invention;

[0035] Figure 3 This is a partial structural cross-sectional view of the cellular prefabricated component provided in an embodiment of the present invention.

[0036] In the picture:

[0037] 1. Preformed tooling; 2. Bottom layer structure; 21. Peelable fabric layer; 22. Prepreg fabric layer; 23. Adhesive film layer; 3. Honeycomb body; 4. Barrier protection components. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0039] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0042] Figure 1 This diagram shows a flowchart of a method for manufacturing cellular preforms according to an embodiment of the present invention. Figure 2 This diagram illustrates a cellular prefabricated component provided in an embodiment of the present invention, with reference to... Figure 1 and Figure 2 This embodiment provides a method for manufacturing a honeycomb preform and a honeycomb preform. The honeycomb preform is manufactured using the method provided in this embodiment, which effectively improves the structural strength and integrity of the honeycomb preform with large thickness and large curvature, reduces defects in the honeycomb preform, and improves the molding quality.

[0043] Continue to refer to Figure 1 The method for manufacturing cellular preforms provided in this embodiment specifically includes the following steps:

[0044] Step S100: Lay the bottom layer structure 2 on the preform tooling 1.

[0045] Specifically, Figure 3A partial structural cross-sectional view of a honeycomb prefabricated component provided in an embodiment of the present invention is shown. (Refer to...) Figure 3 The bottom layup structure 2 includes a peelable fabric layer 21, a prepreg fabric layer 22, and an adhesive film layer 23. Step S100 specifically includes: first, cleaning the surface of the preform tooling 1 and applying a release agent; then proceeding to the following steps:

[0046] Step S110: Lay a peelable fabric layer 21 on the preformed tooling 1 and vacuum compact it;

[0047] Step S120: Lay the prepreg fabric layer 22 on the peelable fabric layer 21 and vacuum compact it;

[0048] Step S130: Lay the adhesive film layer 23 on the prepreg fabric layer 22 and vacuum compact it.

[0049] More specifically, in steps S110, S120, and S130, the pressure during the vacuum compaction process is not less than 90 kPa. Furthermore, the duration of each vacuum compaction step in steps S110, S120, and S130 is not less than 15 minutes. In this embodiment, the prepreg fabric layer 22 is a T300 carbon fiber prepreg fabric. Through the above steps, the reliability of the internal bonding of the bottom layup structure 2 is ensured, and the stability of the bonding between the bottom layup structure 2 and the preforming tooling 1 is guaranteed. The peelable layer 21 can provide an adhesive surface for the connection between the honeycomb preform and the lower skin after the honeycomb preform is formed, eliminating the need for a grinding process on the bonding surface between the honeycomb preform and the lower skin.

[0050] Step S200: A honeycomb body 3 is laid on the bottom layup structure 2, and pressure is applied to the honeycomb body 3 to press it against the bottom layup structure 2, temporarily achieving a bonding effect and forming a honeycomb prefabricated component. In this embodiment, the honeycomb body 3 is an aramid paper honeycomb.

[0051] Step S300: A blocking and protective component 4 is provided around the periphery of the cellular body 3. The blocking and protective component 4 is attached to and surrounds the periphery of the cellular body 3.

[0052] Specifically, in step S300, the upper surface of the barrier protection component 4 protrudes beyond the upper surface of the honeycomb body 3. Preferably, the upper surface of the barrier protection component 4 is 5mm higher than the upper surface of the honeycomb body 3. The barrier protection component 4 forms a stable self-sealing frame structure to resist the pressure of vacuum on the sides of the honeycomb body 3 during the subsequent vacuum curing step, preventing the sides of the honeycomb body 3 from collapsing towards the center. This improves the lateral stiffness of the honeycomb body 3, ensuring production quality.

[0053] Step S400: Vacuum encapsulate the honeycomb body 3 and the barrier protection component 4, and cure the honeycomb preform composed of the bottom layup structure 2 and the honeycomb body 3.

[0054] Specifically, step S400 includes the following steps:

[0055] Step S410: Apply a vacuum sealing layer to the cell body 3 and the barrier protection component 4. The vacuum sealing layer consists of an isolation film, a breathable felt, and a vacuum bag sequentially disposed outside the cell body 3 and the barrier protection component 4.

[0056] Step S420: Vacuum the vacuum bag;

[0057] Step S430: After the vacuum level is qualified, push the device into the autoclave for hot pressing and curing.

[0058] Step S440: Remove the vacuum seal.

[0059] More specifically, in step S430, the curing temperature is 180±5℃, the curing time is not less than two hours, and the curing pressure is 310 kPa. These steps improve the structural consistency and strength of the honeycomb prefabricated components.

[0060] Preferably, after step S400, the following steps are also performed:

[0061] Step S500: Chamfer the sides of the honeycomb preform and round the edges and side edges of the honeycomb preform. In this embodiment, the sides are chamfered at 25° and the edges are rounded with a radius of 20mm. Step S500 allows for shared tooling; the honeycomb preform can be directly chamfered without demolding or secondary positioning on the tooling.

[0062] Finally, the completed honeycomb prefabricated components are used for the layup process of structures such as aircraft doors.

[0063] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing honeycomb prefabricated components, characterized in that, include: S100, Lay the bottom layer structure (2) on the preform tooling (1); S200, A honeycomb body (3) is laid on the bottom layup structure (2), and pressure is applied to the honeycomb body (3) so that the honeycomb body (3) presses against the bottom layup structure (2) to form a honeycomb prefabricated component; S300, a blocking and protective component (4) is provided around the periphery of the cellular body (3), the blocking and protective component (4) abutting against and surrounding the periphery of the cellular body (3); S400, Vacuum encapsulate the honeycomb body (3) and the barrier protection component (4), and cure the honeycomb preform composed of the bottom layup structure (2) and the honeycomb body (3); S500: Chamfer the sides of the honeycomb preform and round the edges of the honeycomb preform. The bottom layup structure (2) includes a peelable fabric layer (21), a prepreg fabric layer (22), and an adhesive film layer (23); step S100 includes: S110. Lay the peelable fabric layer (21) on the preformed tooling (1) and vacuum compact it; S120. Lay the prepreg fabric layer (22) on the peelable fabric layer (21) and vacuum compact it; S130. Lay the adhesive film layer (23) on the prepreg fabric layer (22) and vacuum compact it; Step S400 includes: S410. A vacuum sealing layer is provided over the honeycomb body (3) and the barrier protection component (4), wherein the vacuum sealing layer is an isolation film, a breathable felt and a vacuum bag sequentially disposed outside the honeycomb body (3) and the barrier protection component (4); S420. Vacuum the vacuum bag. S430, hot-press curing; S440, Remove the vacuum seal layer.

2. The method for manufacturing a honeycomb preform according to claim 1, characterized in that, In steps S110, S120 and S130, the pressure during the vacuum compaction process is not less than 90 kPa.

3. The method for manufacturing a honeycomb preform according to claim 1, characterized in that, In steps S110, S120 and S130, the duration of each vacuum compaction is not less than 15 minutes.

4. The method for manufacturing a honeycomb preform according to claim 1, characterized in that, In step S300, the upper end face of the blocking and protection component (4) protrudes from the upper end face of the cellular body (3).

5. The method for manufacturing a honeycomb preform according to claim 4, characterized in that, The upper surface of the blocking and protection component (4) is 5 mm higher than the upper surface of the cellular body (3).

6. A honeycomb prefabricated component, characterized in that, The cellular preform is manufactured using the cellular preform manufacturing method as described in any one of claims 1-5.

7. The honeycomb prefabricated component according to claim 6, characterized in that, The honeycomb body (3) is an aramid paper honeycomb.

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