A grid stiffened panel for aircraft structures and a forming tool and method therefor

Abstract

The present application belongs to the technical field of grid stiffened wall panels, and particularly relates to a grid stiffened wall panel for an aircraft structure, a forming die and a method thereof, comprising a grid frame, a skin plate arranged on the grid frame, the skin plate comprising an outer skin arranged on the bottom surface of the grid frame and an inner skin arranged on the grid frame, the grid frame comprising a transverse rib core material and a longitudinal rib core material connected to each other, the inner skin being located between the transverse rib core material and the longitudinal rib core material, a connection between the transverse rib core material and the longitudinal rib core material being referred to as a connection node, and a forming block being arranged on each connection node; the forming block effectively enhances the strength and stability of the grid frame. In addition, through the edge folding of the inner skin, the transverse rib core material and the longitudinal rib core material are tightly fixed, thereby significantly improving the strength and structural efficiency of the grid stiffened wall panel. The unique requirements of the wall panel structure of the aircraft and other aircrafts in transmitting and bearing large loads are met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of grid stiffened panels, and particularly relates to a grid stiffened panel for aircraft structure and a forming die and method thereof. BACKGROUND

[0002] In the design of modern aircraft, the fuselage door, landing gear door and other key structures usually adopt thin-walled integral stiffened panel structure. This structure combines thin walls with stiffening elements to improve the overall strength and stiffness. The traditional stiffened panel structure mainly relies on the mechanical connection between the stringers and the rib strips to form a typical stiffened panel. As the main load-bearing elements, the stringers and the rib strips are tightly combined through rivets, bolts or other mechanical connection methods to ensure the integrity and load-bearing capacity of the structure.

[0003] However, in practical applications, the existing stiffened panel structure has the problem of insufficient strength. Since the thin-walled structure is prone to deformation under external loads, the traditional mechanical connection method may loosen or be damaged during long-term use, resulting in a decline in the overall performance of the structure. In addition, with the continuous development of aviation technology, the requirements for lightweight and high-performance of the structure are becoming higher and higher, and the traditional stiffened panel structure has been difficult to meet the comprehensive demands of modern aircraft for strength, stiffness and durability. SUMMARY

[0004] The purpose of the present application is to overcome the above-mentioned deficiencies and provide a grid stiffened panel for aircraft structure and a forming die and method thereof.

[0005] To achieve the above-mentioned purpose, the present application provides a grid stiffened panel for aircraft structure, comprising a grid frame, a skin plate arranged on the grid frame, the skin plate comprising an outer skin arranged on the bottom surface of the grid frame and an inner skin arranged on the grid frame, the grid frame comprising connected horizontal core material and vertical core material, the inner skin being located between the horizontal core material and the vertical core material, the connection between the horizontal core material and the vertical core material being referred to as a connection node, a shaped block being arranged on the connection node, the shaped block being a preform composed of carbon fiber and resin, the shaped block comprising a reinforcing element distributed upward and downward, the reinforcing element comprising a top plate and a limiting block arranged at the bottom of the top plate, the limiting block forming a slot for inserting the horizontal core material and the vertical core material, and a cutout being arranged in the corner area of the inner skin.

[0006] Further, a limiting extension is arranged on the top plate, and the limiting extension is in contact with the top surface of the inner skin.

[0007] Further, twist strips are filled on both sides of the horizontal core material and the vertical core material, and the twist strips are located at the connection between the horizontal core material and the outer skin and between the vertical core material and the outer skin.

[0008] Further, the outer skin is provided with a reinforcing layer at a position corresponding to the connecting node.

[0009] The application further provides a forming die for the grid reinforced wallboard, comprising a die body, the die body comprising a frame, an inner core module arranged on one side of the grid reinforced wallboard, and a pressing cover arranged on one side of the grid reinforced wallboard, a die cavity for forming the grid reinforced wallboard being formed between the frame, the inner core module and the pressing cover.

[0010] Further, the frame comprises detachably connected horizontal frames and vertical frames.

[0011] Further, the inner core module comprises a plurality of inner cores arranged between the horizontal core material and the vertical core material.

[0012] The application further provides a forming method for the grid reinforced wallboard, comprising the following steps:

[0013] A grid frame processing step: the horizontal core material and the vertical core material are engaged with each other to form a grid frame;

[0014] An inner skin pasting step: the inner skin is pasted on the inner core module, and the grid frame is clamped into the inner core module;

[0015] A twist bar filling step: a twist bar is filled on the surface of the inner skin;

[0016] A forming block installation step: a forming block is inserted at each connecting node position;

[0017] An outer skin pasting step: an outer skin is pasted on the surface;

[0018] A frame assembling step: the frame is assembled and the pressing cover is installed;

[0019] A curing forming step: the whole is bagged, then vacuumized, and then cured;

[0020] A demolding step: after the curing forming, demolding is performed.

[0021] The technical scheme provided by the application has at least the following technical effects:

[0022] The grid reinforced wallboard disclosed by the application is provided with a forming block at the connecting node of the horizontal core material and the vertical core material, which effectively enhances the strength and stability of the grid frame. In addition, the horizontal core material and the vertical core material are tightly fixed through the flanging of the inner skin, thereby significantly improving the strength and structural efficiency of the grid reinforced wallboard. The unique requirements of the wallboard structure of an aircraft and other aircrafts in transmitting and bearing large loads are met. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0024] Figure 1 Structure diagram of the grid reinforced wallboard of the embodiment 1 of the present application;

[0025] Figure 2 Exploded view of the grid reinforced wallboard of the embodiment 1 of the present application;

[0026] Figure 3 Structure diagram of the reinforcing block of the embodiment 1 of the present application;

[0027] Figure 4 Structure diagram of the twist bar distribution of the embodiment 1 of the present application;

[0028] Figure 5 Unfolding and flanging diagram of the inner skin of the embodiment 1 of the present application;

[0029] Figure 6 Structure diagram of the distribution of the reinforcing layer of the embodiment 1 of the present application;

[0030] Figure 7 Structure diagram of the forming mold of the embodiment 2 of the present application;

[0031] Figure 8 Exploded view of the forming mold of the embodiment 2 of the present application.

[0032] Main drawing mark explanation: 1, horizontal rib core material; 2, vertical rib core material; 3, outer skin; 4, inner skin; 5, reinforcing member; 51, top plate; 52, limiting block; 53, insertion slot; 54, limiting extension; 6, twist bar; 7, horizontal frame; 8, vertical frame; 9, inner core; 10, pressing cover plate; 11, shearing opening; 12, flange; 13, reinforcing layer. DETAILED DESCRIPTION

[0033] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the embodiments of the present application, and cannot be understood as a limitation of the present application.

[0034] Embodiment 1: as Figure 1 , Figure 2As shown in the figure, a grid stiffened panel for aircraft structure comprises a grid frame on which a skin plate is arranged. The skin plate is composed of an outer skin 3 arranged on the bottom surface of the grid frame and an inner skin 4 arranged on the grid frame. The grid frame is composed of transverse rib core materials 1 and longitudinal rib core materials 2 connected to each other, and the inner skin 4 is arranged between the transverse rib core materials 1 and the longitudinal rib core materials 2, and the inner skin 4 is specifically arranged in the grid formed by the transverse rib core materials 1 and the longitudinal rib core materials 2. The transverse rib core materials 1 and the longitudinal rib core materials 2 are tightly fixed through the covering of the flanges 12 of the inner skin 4 and the covering of the outer skin 3, thereby significantly improving the strength and structural efficiency of the grid stiffened panel. Figure 5 As shown in the figure, a shear opening 11 is arranged in the corner area of each inner skin 4, and the flanges 12 in the direction of the transverse rib core materials 1 and the longitudinal rib core materials 2 are used to cover the transverse rib core materials 1 and the longitudinal rib core materials 2.

[0035] The connection between the transverse rib core materials 1 and the longitudinal rib core materials 2 is called a connection node, and a shaped block is arranged on each connection node. The shaped block comprises upper and lower reinforcing members 5, and the connection node position is further tightly fixed through the reinforcing members 5, thereby further significantly improving the strength and stability of the grid stiffened panel. As shown in the figure, Figure 3 As shown in the figure, in this embodiment, the reinforcing member 5 comprises a top plate 51 and a limiting block 52 arranged at the bottom of the top plate 51, and the limiting block 52 forms a slot 53 for inserting the transverse rib core materials 1 and the longitudinal rib core materials 2. Specifically, four limiting blocks 52 are circumferentially arranged at the bottom of the top plate 51 to form a cross slot, and the transverse rib core materials 1 and the longitudinal rib core materials 2 are inserted into the cross slot, and under the action of the reinforcing member 5, the connection between the transverse rib core materials 1 and the longitudinal rib core materials 2 is more stable. Since the grid stiffened panel in this embodiment is an orthogonal grid panel, the slot 53 in this embodiment is a cross-shaped slot 53, but in addition to the orthogonal grid panel, the grid stiffened panel can also be a special-shaped grid panel, so the shape of the slot 53 can be changed according to the shape of the special-shaped connection node. In this embodiment, the reinforcing member 5 is made of fiber resin material, which has excellent tensile and bending resistance. Specifically, it is a preformed body composed of carbon fiber and resin block. The preparation of the preformed body can adopt unidirectional tape, and the corresponding mold is heated and pressed to form the preformed body. The reinforcing member 5 is directly clamped into the gap between the transverse rib core materials 1, the longitudinal rib core materials 2 and the skin plate, and the transverse rib core materials 1 and the longitudinal rib core materials 2 are directly inserted into the slot 53. The whole is solidified at one time, and a force transmission node is formed.

[0036] As shown in the figure, Figure 3 A limiting extension 54 is arranged on the top plate 51, and the limiting extension 54 is in contact with the top surface of the inner skin 4. The stability of the connection between the inner skin 4 and the transverse rib core materials 1 and the longitudinal rib core materials 2 is improved under the action of the limiting extension 54.

[0037] In order to further improve the overall strength of the grid reinforced wallboard, twisted strips 6 are filled on both sides of the horizontal rib core material 1 and the longitudinal rib core material 2, which can be formed by unidirectional tape fibers through mold pressing. As shown in Figure 4 , these twisted strips 6 are located at the connecting parts of the horizontal rib core material 1 and the outer skin 3, and the longitudinal rib core material 2 and the outer skin 3. The role of the twisted strip 6 is to fill the gap between the inner skin 4, the outer skin 3, and the horizontal rib core material 1 and the longitudinal rib core material 2, so that the forming between the inner skin 4, the outer skin 3, the horizontal rib core material 1 and the longitudinal rib core material 2 is more stable, as shown in Figure 6 , the outer skin 3 is provided with a reinforcing layer 13 at the position corresponding to the connecting node, so that the axial and shear strength of the connecting node area in two directions is significantly improved.

[0038] Example 2: As shown in Figure 7 , Figure 8 , this embodiment discloses a mold for forming the grid reinforced wallboard of example 1, which comprises a mold body. The mold body comprises a frame, an inner core module arranged on one side of the grid reinforced wallboard, and a pressing cover plate 10 arranged on the other side of the grid reinforced wallboard, which forms a mold cavity for forming the grid reinforced wallboard. The frame is composed of two detachably connected horizontal frame 7 and longitudinal frame 8, and the detachable connection between the horizontal frame 7 and the inner core module can be realized by connecting members such as bolts. The inner core module contains a plurality of inner cores 9, which are arranged in the square between the horizontal rib core material 1 and the longitudinal rib core material 2. In the mold cavity formed by the frame, the pressing cover plate 10 and the inner core module, the grid reinforced wallboard described in example 1 is integrally solidified and formed.

[0039] Example 3: This embodiment discloses a forming method of grid reinforced wallboard, the specific steps are as follows:

[0040] Firstly, the processing of grid frame is carried out. In this embodiment, four horizontal rib core materials 1 and three longitudinal rib core materials 2 are prepared. The horizontal rib core material 1 and the longitudinal rib core material 2 are engaged with each other through the clamping groove to form the grid frame.

[0041] Then the inner skin 4 is laid. The inner cores 9 of the inner core module are arranged in order to ensure their flatness. Then, the inner skin 4 is evenly laid on the inner cores 9. Finally, the previously processed grid frame is clamped into the inner core module to ensure that it is firmly fixed on the inner skin 4.

[0042] Then, the twisted strip 6 is filled. The twisted strip 6 needs to be evenly filled on the surface of the inner skin 4. The twisted strip 6 needs to be distributed on both sides of the horizontal rib core material 1 and the longitudinal rib core material 2 to ensure the stability and strength of the overall structure.

[0043] Then, the installation of the shaped blocks is performed. The shaped blocks are inserted into the slots 53 of the horizontal rib core 1 and the vertical rib core 2 at the respective connecting node positions of the horizontal rib core 1 and the vertical rib core 2. The shaped blocks are inserted into the slots 53 of the horizontal rib core 1 and the vertical rib core 2 to further strengthen the stability of the structure.

[0044] After that, the laying of the outer skin 3 is performed. The outer skin 3 is laid on the surface uniformly to form the outer surface of the wallboard.

[0045] Next, the assembly of the frame is performed. The frame is assembled by connecting the two horizontal frames 7 and the vertical frame 8 by means of connecting members such as bolts, and the pressurizing cover plate 10 is installed to ensure the integrity and sealing of the overall structure.

[0046] Then, the solidification molding is performed. The overall bagging is performed, and then vacuum is drawn to perform the solidification. The stability and strength of the wallboard are ensured.

[0047] Finally, the demolding is performed. After the solidification molding, the demolding is performed. After the demolding, the top surface and the edge of the wallboard are machined and edge-sealed to ensure the flatness and the aesthetic appearance. Finally, the inspection is performed to ensure that the quality of the wallboard meets the standards.

[0048] The above shows and describes the basic principles, main features and advantages of the present application. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Various changes and improvements can be made to the present application without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the present application. The scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A grid-stiffened panel for use in an aircraft structure, characterized by, The application relates to a grid framework, wherein a skin plate is arranged on the grid framework, the skin plate comprises an outer skin (3) arranged on the bottom surface of the grid framework and an inner skin (4) arranged on the grid framework, the grid framework comprises transverse rib core materials (1) and longitudinal rib core materials (2) connected with each other, the inner skin (4) is located between the transverse rib core materials (1) and the longitudinal rib core materials (2), the connection between the transverse rib core materials (1) and the longitudinal rib core materials (2) is called a connecting node, and a shaped block is arranged on each connecting node, the shaped block is a preformed body composed of carbon fibers and resin blocks, the shaped block comprises upper and lower reinforcing members (5), the reinforcing member (5) comprises a top plate (51) and a limiting block (52) arranged at the bottom of the top plate (51), the limiting block (52) forms a slot (53) for inserting the transverse rib core materials (1) and the longitudinal rib core materials (2), the corner area of the inner skin (4) is provided with a shearing port (11), and the two sides of the transverse rib core materials (1) and the longitudinal rib core materials (2) are filled with twist strips (6), and the twist strips (6) are located at the connecting positions of the transverse rib core materials (1) and the outer skin (3) and the longitudinal rib core materials (2) and the outer skin (3).

2. The grid-stiffened panel for aircraft structures of claim 1, wherein, A limiting extension (54) is arranged on the top plate (51) and is in contact with the top surface of the inner skin (4).

3. The grid-stiffened panel for aircraft structures of Claim 1, wherein, A reinforcing layer (13) is arranged at the position corresponding to the connecting node of the outer skin (3).

4. A forming die for lattice stiffened panels according to any one of claims 1 to 3, characterised in that, The application relates to a mold body, which comprises a frame, an inner core module arranged on one side of a grid reinforced wall plate and a pressing cover plate (10) arranged on one side of the grid reinforced wall plate, and a mold cavity for forming the grid reinforced wall plate is formed among the frame, the inner core module and the pressing cover plate (10).

5. The forming mold of claim 4, wherein, The frame comprises detachably connected transverse frames (7) and longitudinal frames (8).

6. The forming mold of claim 4, wherein The inner core module comprises a plurality of inner cores (9) arranged between the transverse rib core materials (1) and the longitudinal rib core materials (2).

7. A method of forming a grid-stiffened panel using the forming mold of any one of claims 4-6, wherein, The application comprises the following steps: A grid framework processing step: the transverse rib core materials (1) and the longitudinal rib core materials (2) are engaged with each other to form a grid framework; An inner skin (4) laying step: the inner skin (4) is laid on the inner core module, and the grid framework is clamped into the inner core module; A twist strip (6) filling step: the twist strip (6) is filled on the surface of the inner skin (4); A shaped block mounting step: the shaped block is inserted into each connecting node position; An outer skin (3) laying step: the outer skin (3) is laid on the surface; A frame assembling step: the frame is assembled and the pressing cover plate (10) is mounted; A curing forming step: the whole is bagged, and then vacuumized; Curing is performed; A demolding step: after curing forming, demolding is performed.

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