A kind of angle bar layer structure suitable for multi-curvature composite airfoil of anti-thrust device

Abstract

The application belongs to the technical field of engine design, and particularly relates to an angle bar layering structure suitable for a multi-curvature composite material blade row of a counter-thrust device. The blade row comprises circumferential blades (1) and axial blades (2), the circumferential blades (1) and the axial blades (2) form a grid with different curvatures, the circumferential blades (1) are a plurality of strip structures designed side by side, each circumferential blade (1) is formed by continuous laying of carbon fiber unidirectional tape or fabric after cutting, the axial blade (2) comprises a plurality of axial blade segments, a plurality of axial blade segments are designed side by side between adjacent circumferential blades (1), each axial blade segment is cut and laid by carbon fiber unidirectional tape or fabric alone, and each circumferential blade (1) and the plurality of axial blade segments adjacent thereto are connected through a U-shaped angle bar (3). The application can utilize the high strength and high modulus of the fiber along the axial direction and the load consistent with the stress direction of the blade row to improve the overall carrying capacity of the blade row structure.

Description

Technical Field

[0001] This application belongs to the field of engine design technology, specifically relating to a corner piece layup structure suitable for multi-curvature composite material blade cascades in thrust reversers. Background Technology

[0002] Blade-type thrust reversers are an important component of the power systems of large transport aircraft and passenger aircraft. Their main function is to generate reverse thrust by changing the direction of engine exhaust flow, enabling the aircraft to decelerate efficiently and reliably. This can significantly shorten the landing roll distance, reduce the requirements of the airport, and improve the airport's operational efficiency and the safety of aircraft operations.

[0003] As a core component of the blade-type thrust reverser that controls the reverse airflow, such as Figure 1 and Figure 2 As shown, Figure 1 This is a schematic diagram of the engine with thrust reversers off. Figure 2 This is a schematic diagram of the engine with thrust reversers engaged. As shown, thrust reversers are engaged by sliding the outer casing 100 backward. Simultaneously, a flow deflector inside the engine blocks the continued rearward emission of the bypass air, instead directing exhaust through the exposed blades 200. The bypass airflow, deflected by the flow deflector, is discharged through the grid, thus generating reliable reverse thrust. With increasing customer demands for aircraft fuel economy, the blade structure has been designed using composite materials.

[0004] The blade cascade consists of intersecting blades distributed circumferentially and axially, forming a multi-curvature grid structure. The blades of the cascade should meet the aerodynamic requirements, wherein the circumferential blades continuously provide circumferential airflow deflection angle along the axial direction, and the axial blades continuously provide axial airflow deflection angle along the circumferential direction, with cross joints or T-joints formed between the blades.

[0005] Existing composite material blade cascades use an interlocking structure, and the molding scheme is roughly as follows:

[0006] First, the axial and circumferential blades are cured and molded separately, and the upper and lower surfaces and slotted positions are machined. Figure 3 A schematic diagram of the circumferential blade slotting is provided. Figure 4 A schematic diagram of the slotted axial blades is provided. Then, the axial and circumferential blades are inserted together, and a core mold is filled to position the blades before fixing them onto the molding fixture. Finally, the mold is closed and resin is injected for high-temperature curing. After molding, the core mold is removed, and the grid structure is finally formed.

[0007] Traditional composite blade cascades use a blade interlocking structure and secondary curing molding, which has the following disadvantages:

[0008] 1) Because the plug-in structure requires slotting the blades, it disrupts the continuity of the fibers, reduces the structural load-bearing capacity, and is not conducive to the load transfer of the overall structure.

[0009] 2) According to the actual stress conditions of the structure, the circumferential blades of the blade cascade usually bear a much higher load than the axial blades. However, the plug-in structure weakens both equally and cannot adapt to the actual load characteristics of the blade cascade.

[0010] 3) The circumferential and axial blades of the plug-in structure are of equal thickness, which makes it impossible to carry out fine design according to the actual load conditions, cannot adapt to the design strength characteristics of composite materials, and is not conducive to structural weight reduction.

[0011] 4) The plug-in structure requires the blades to be cured separately and then glued together twice, which requires two autoclave curing processes, resulting in low efficiency and high cost.

[0012] 5) The blades of the plug-in structure require a slotted structure to be machined. The slotted structure has high requirements for size and positioning accuracy, the process is complex and cumbersome, and the scrap rate is high.

[0013] 6) The plug-in structure is connected only by injection molding resin at the connection point, without fiber reinforcement. After long-term use, the resin matrix is ​​prone to cracking, affecting the appearance quality and structural reliability. Summary of the Invention

[0014] To address one of the aforementioned problems, this application provides a U-shaped angled brace layup structure suitable for multi-curvature composite material blade cascades in thrust reversers. The blade cascade includes circumferential blades and axial blades, with a grid of different curvatures formed between the circumferential and axial blades. The circumferential blades are multiple parallel strip structures, each formed by continuously laying out carbon fiber unidirectional tape or fabric after cutting. The axial blades include multiple axial blade segments, with multiple axial blade segments arranged side-by-side between adjacent circumferential blades. Each axial blade segment is individually cut and laid out from carbon fiber unidirectional tape or fabric. Each circumferential blade is connected to its adjacent multiple axial blade segments by U-shaped angled braces.

[0015] Preferably, the U-shaped angle is formed of carbon fiber fabric.

[0016] Preferably, the U-shaped angle bracket includes three U-shaped plates connected in sequence, with the middle plate connected to an axial blade segment between two circumferentially arranged blades, and the plates at both ends connected to two circumferentially arranged blades respectively.

[0017] Preferably, each axial leaf segment between two adjacent circumferential blades is connected to a U-shaped angle bracket on both sides.

[0018] Preferably, the blade cascade further includes a circumferential frame located at the end of the blade cascade, arranged parallel to the circumferential blades, located at the end of each circumferential blade, and an axial frame is provided between adjacent circumferential blades. The circumferential frame and the axial frame are connected by a C-shaped angle bracket. The C-shaped angle bracket is formed by opening a notch on one side of a cylindrical structure and is connected to the surrounding structure within the cascade grid.

[0019] Preferably, the four sides of the C-shaped angle are connected to a circumferential frame, a circumferential blade opposite to the circumferential frame, an axial frame, and an axial blade segment opposite to the axial frame, wherein the side with the notch is connected to the circumferential blade.

[0020] Preferably, the circumferential blade has a blade edge extending to the mounting edge of the engine. The mounting edge and the axial frame are connected by an I-shaped box-shaped angle bracket. The I-shaped box-shaped angle bracket has a first lower plate surface and a first front plate surface. These two plates are connected to the mounting edge and the axial frame respectively on the outside of the box body. A first side plate surface is designed on the side of these two vertical plates. The first side plate surface is correspondingly attached to the blade edge, and a first overlapping area is formed at the first side plate surface by layering and folding the box-shaped angle bracket.

[0021] Preferably, a T-shaped box-shaped corner piece is stacked inside the box on the I-type box-shaped corner piece away from the mounting edge and the axial frame. The T-shaped box-shaped corner piece has a second front plate surface and a second side plate surface corresponding to the second lower plate surface of the I-type box-shaped corner piece. The second front plate surface forms a second overlapping area by folding the box-shaped corner piece.

[0022] The angled burl layup structure for multi-curvature composite blade cascades proposed in this invention changes the structural characteristics and connection methods of traditional composite blade cascades. It uses various shaped angled burls to achieve bonding between different parts of the blade cascade, replacing the traditional plug-in blade connection method. The benefits include:

[0023] Technical aspects: The various angle connecting structures described in this invention can realize the partitioned design of the blade cascade. Independent designs can be carried out for circumferential and axial blades, etc., maintaining the continuity of the main load-bearing structure fibers of the blade cascade, improving the load-bearing capacity of the blade cascade structure, adapting to the design characteristics of composite material structures, improving the independent designability of each part of the composite material blade cascade, obtaining higher structural weight reduction benefits, and realizing reliable connection of cross grid structures.

[0024] In terms of cost: The various angle-fitting connection structures described in this invention enable low-cost manufacturing of blade cascades. During production, only the laying of blades, frames, and angle-fitting structures on a molding die is typically required. Forming can be achieved through a single curing process. After curing, only machining of the blade cascade outline is needed to obtain the final dimensions. This invention eliminates the complex processes of traditional plug-in composite material blade cascades, such as blade slotting, plug-in positioning, and repeated canning, simplifying the manufacturing process, increasing yield, and reducing parts manufacturing costs. Attached Figure Description

[0025] Figure 1 This is a diagram illustrating the reverse-direction closed state.

[0026] Figure 2 This is a diagram illustrating the reverse open state.

[0027] Figure 3 This is a schematic diagram of circumferential blade slotting.

[0028] Figure 4 This is a schematic diagram of the slotting of the axial blade.

[0029] Figure 5 This is a schematic diagram of a U-shaped angle connection of a preferred embodiment of the angle layup structure applicable to the multi-curvature composite material blade cascade of the thrust reverser provided in this application.

[0030] Figure 6 yes Figure 5 Exploded view of the embodiment shown.

[0031] Figure 7 This is a schematic diagram of a C-shaped angle bracket connection according to a preferred embodiment of this application.

[0032] Figure 8 yes Figure 7 Exploded view of the embodiment shown.

[0033] Figure 9 This is a schematic diagram of the boxed corner piece connection according to a preferred embodiment of this application.

[0034] Figure 10 yes Figure 9 Exploded view of the embodiment shown.

[0035] Figure 11 yes Figure 9 The diagram shows a schematic of the Type I boxed angle bracket structure in the embodiment shown.

[0036] Figure 12 yes Figure 11 The illustrated embodiment shows a schematic diagram of the unfolded I-type boxed angle member structure.

[0037] Figure 13 yes Figure 9 A schematic diagram of the T-shaped boxed angle bracket structure of the embodiment shown.

[0038] Figure 14 yes Figure 13 A schematic diagram of the unfolded T-shaped boxed angle bracket structure of the embodiment shown.

[0039] Among them, 1-circumferential blade, 2-axial blade, 3-U-shaped angle, 4-C-shaped angle, 5-I-shaped boxed angle, 6-T-shaped boxed angle, 7-circumferential frame, 8-axial frame, 9-installation edge, 10-first overlapping area, 11-second overlapping area. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0041] This application provides a corner piece layup structure suitable for multi-curvature composite material blade cascades in thrust reversers, which has the following characteristics:

[0042] 1) The fiber layup should be continuous and should be able to withstand loads in the same direction as the blade cascade by utilizing the high strength and high modulus of the fibers along their axial direction, thereby improving the structural load-bearing capacity.

[0043] 2) For circumferential and axial blades, the load-bearing and load-transfer characteristics of the blade cascade structure should be adapted, and the overall safety reserve level of the structure should be comprehensively considered to balance the structural strength reserve in high and low load areas in order to improve the structural strength in high load areas.

[0044] 3) The blades of the cascade should be designed independently, and the thickness of different parts should be designed to vary according to the actual load to meet the requirements of local optimization design and improve the weight reduction benefits;

[0045] 4) To meet the requirements of low-cost manufacturing, a single-curing process should be adopted to improve efficiency and reduce costs;

[0046] 5) The structure should be simple and reliable, avoiding excessive processing steps, adapting to integrated molding, and improving manufacturing quality;

[0047] 6) The connection parts should be reinforced with reinforcing materials to improve surface quality and enhance structural durability and reliability.

[0048] The thrust reverser device of this application uses a multi-curvature composite material blade cascade with a plywood structure. The blade cascade includes circumferential blades 1 and axial blades 2, with a grid of different curvatures formed between the circumferential blades 1 and the axial blades 2, such as... Figure 5-14 The circumferential blade 1 is a strip structure designed side by side. Each circumferential blade 1 is formed by continuously laying out carbon fiber unidirectional tape or fabric after cutting. The axial blade 2 includes multiple axial blade segments. Multiple axial blade segments are designed side by side between adjacent circumferential blades 1. Each axial blade segment is individually cut and laid out by carbon fiber unidirectional tape or fabric. Each circumferential blade 1 and its adjacent multiple axial blade segments are connected by U-shaped angle brackets 3.

[0049] The purpose of this application is to provide a composite material layup structure with high load-bearing capacity, reliable connection, and independent designability suitable for multi-curvature, cross-connected, and complex lattice structures. This structure adapts to the load-bearing and load-transfer characteristics of the structure, uses angled baffle layup for connection, and achieves the aerodynamic and structural requirements of composite material blade cascades while possessing high reliability, good appearance quality, simple process, low cost, and high efficiency. Its core is a typical blade structure connected by angled baffles. First, carbon fiber unidirectional tape / fabric is cut and continuously laid to form a circumferential blade 1; then, carbon fiber unidirectional tape / fabric is cut and laid to form individual axial blades 2, i.e., axial blade segments; according to the theoretical connection position of each blade, they are laid and assembled in a molding die, and the axial blades 2 are connected to the circumferential blades 1 by U-shaped angled baffles 3 of carbon fiber fabric.

[0050] In some alternative embodiments, the U-shaped angle 3 is formed of carbon fiber fabric.

[0051] In some alternative implementations, such as Figure 5 and Figure 6 As shown, the U-shaped angle member 3 includes three U-shaped plates connected in sequence. The middle plate is connected to an axial blade segment between two parallel circumferential blades 1, and the plates at both ends are connected to two parallel circumferential blades 1 respectively.

[0052] In some alternative embodiments, each axial blade segment between two adjacent circumferential blades 1 is connected to a U-shaped angle bracket 3 on both sides. The blade structure connected by angle brackets can achieve the original blade cascade structure form, and because the circumferential blade 1 has continuous and complete fiber layup without gaps, it can utilize the high strength and high modulus of the fibers along their axial direction and the load consistent with the direction of force on the blade cascade to improve the overall load-bearing capacity of the blade cascade structure.

[0053] In some alternative embodiments, the blade cascade further includes a circumferential frame 7 located at the end of the blade cascade, arranged parallel to the circumferential blade 1, located at the end of each circumferential blade 1, and an axial frame 8 is provided between adjacent circumferential blades 1. The circumferential frame 7 and the axial frame 8 are connected by a C-shaped angle bracket 4, which is formed by opening a notch on one side of a cylindrical structure and is connected to the surrounding structure within the cascade grid.

[0054] In some alternative embodiments, the four sides of the C-shaped angle bracket 4 are respectively connected to a circumferential frame 7, a circumferential blade 1 opposite to the circumferential frame 7, an axial frame 8, and an axial blade segment opposite to the axial frame 8, wherein one side with a notch is connected to the circumferential blade 1. For example... Figure 7 and Figure 8 As shown, the circumferential frame 7 and the axial frame 8 of the blade cascade are connected by C-shaped corner pieces 4, and the corner parts of the frame are locally reinforced.

[0055] In some alternative embodiments, the circumferential blade 1 has a blade edge extending to the mounting edge 9 of the engine. The mounting edge 9 and the axial frame 8 are connected by an I-shaped box-shaped angle bracket 5. The I-shaped box-shaped angle bracket 5 has a first lower plate surface and a first front plate surface. These two plates are connected to the mounting edge 9 and the axial frame 8 on the outside of the box body, respectively. A first side plate surface is designed on the side of these two vertical plates. The first side plate surface is correspondingly attached to the blade edge, and a first overlapping area 10 is formed at the first side plate surface by folding the box-shaped angle bracket.

[0056] In some optional embodiments, a T-shaped box-shaped angle 6 is stacked on the inner side of the box on the I-shaped box-shaped angle 5 away from the mounting edge 9 and the axial frame 8. The T-shaped box-shaped angle 6 has a second front plate surface and a second side plate surface corresponding to the second lower plate surface of the I-shaped box-shaped angle 5. The second front plate surface is formed by folding the box-shaped angle 6 into a second overlapping area 11.

[0057] like Figure 9 and Figure 10 As shown, the circumferential blades 1 continuously extend to the mounting edge 9. Between the axial frame 8 and the mounting edge 9, a connection is achieved through the overlapping of I-shaped box-shaped angle brackets 5 and T-shaped box-shaped angle brackets 6, simultaneously reinforcing the circumferential blades 1 to form a reinforcing rib structure. Details of the box-shaped structure are shown below. Figures 11-14 As shown, the box-shaped corner piece layup adopts an overlapping scheme, which strengthens the local connection strength of the three-sided transition area through the overlapping area.

[0058] It should be noted that the angle connection structure provided in this application is usually composed of multiple layers of carbon fiber unidirectional tape / fabric. To meet the connection requirements of different parts, it can be cut into various shapes such as U-shape, C-shape, I-shape, and T-shape. According to the theoretical design state of the blade cascade, the laying, assembly and positioning are completed by using molding molds, making full use of the strong designability of composite materials.

[0059] This application presents a composite material layup structure with high load-bearing capacity, reliable connection, and independent designability, suitable for complex grid structures with multiple curvatures and cross connections. The high load-bearing capacity refers to the avoidance of slotting in the blade structure through angle brace connections, thereby ensuring the integrity of the circumferential blades 1, the main load-bearing structure. Utilizing continuous, uninterrupted fibers to withstand higher loads adapts to the load-bearing characteristics of the blade cascade and the design requirements of composite material structures, significantly improving the structural load-bearing capacity. The reliable connection refers to the reinforcement of the connection points between the circumferential blades 1 and axial blades 2, axial blades 2 and circumferential frame 7, circumferential frame 7 and axial frame 8, circumferential blades 1 and axial frame 8, and mounting edge 9 through angle brace layup design and overlap area design, achieving reliable connection of the cross-grid structure. The independent designability refers to the division of the circumferential blades 1, axial blades 2, circumferential frame 7, and axial frame 8 into independent structures through angle brace connections. Individual blades can be reinforced according to the actual stress conditions of the blade cascade, achieving local optimization design of each structure and significantly improving the structural weight reduction benefits.

[0060] Although this application has been described in detail above with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, such modifications or improvements made without departing from the spirit of this application are all within the scope of protection claimed in this application.

Claims

1. A structure of angle ply for a multi-curvature composite cascade of a counter- thrust device, the cascade comprising circumferential vanes (1) and axial vanes (2) forming a grid with different curvatures between the circumferential vanes (1) and the axial vanes (2), characterized in that, The circumferential blade (1) is a plurality of side-by-side designed strip structures, each circumferential blade (1) is formed by continuous laying of carbon fiber unidirectional tape or fabric after cutting, the axial blade (2) includes a plurality of axial blade segments, a plurality of axial blade segments are designed side by side between adjacent circumferential blades (1), each axial blade segment is cut and laid by carbon fiber unidirectional tape or fabric alone, each circumferential blade (1) and the plurality of axial blade segments adjacent thereto are connected by a U-shaped angle material (3); The U-shaped angle material (3) is formed by carbon fiber fabric; the U-shaped angle material (3) includes three plate surfaces connected in sequence in a U-shaped structure, the plate surface in the middle is connected with an axial blade segment between two side-by-side designed circumferential blades (1), and the plate surfaces at both ends are connected with two side-by-side designed circumferential blades (1) respectively; each axial blade segment between two adjacent circumferential blades (1) has one U-shaped angle material (3) connected on each side thereof; The cascade further includes a circumferential frame (7) arranged in parallel with the circumferential blade (1) at the end of the cascade, an axial frame (8) is arranged between each circumferential blade (1) at the end thereof and between adjacent circumferential blades (1), the circumferential frame (7) and the axial frame (8) are connected by a C-shaped angle material (4), the C-shaped angle material (4) is formed by an opening on one side of a cylindrical structure and is connected with the structures around it in the grid of the cascade; four sides of the C-shaped angle material (4) are connected with the circumferential frame (7), one circumferential blade (1) opposite to the circumferential frame (7), the axial frame (8), and one axial blade segment opposite to the axial frame (8) respectively, wherein the side with the opening is connected with the circumferential blade (1); The circumferential blade (1) has a blade edge penetrating to a mounting edge (9) of the engine, the mounting edge (9) and the axial frame (8) are connected by an I-shaped box angle material (5), the I-shaped box angle material (5) has a first lower plate surface and a first front plate surface, the two plate surfaces are connected with the mounting edge (9) and the axial frame (8) respectively outside the box body, and a first side plate surface is designed on the side of the two perpendicular plate surfaces, the first side plate surface corresponds to the blade edge, and a first lap joint area is formed by box angle material lay folding at the first side plate surface; A T-shaped box angle material (6) is nested and laid on the inside of the box body of the I-shaped box angle material (5) away from the mounting edge (9) and the axial frame (8), the T-shaped box angle material (6) has a second front plate surface and a second side plate surface corresponding to the second lower plate surface of the I-shaped box angle material (5), and the second front plate surface forms a second lap joint area by box angle material lay folding.

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