A three-dimensional woven sandwich composite aircraft leading edge skin and its manufacturing method

Abstract

The present invention belongs to the field of wing manufacturing technology, and specifically relates to a three-dimensional woven sandwich composite aircraft leading edge skin and a manufacturing method thereof. The three-dimensional woven preform for the aircraft leading edge skin provided by the present invention has an aircraft leading edge curved surface profiling structure; the three-dimensional woven preform is woven into an integral body, and the warp direction of the integrally woven preform is the same as the aircraft leading edge span direction, and the warp yarns form multiple warp yarn layers, and the warp yarns in each warp yarn layer are arranged along the curved profiling of the aircraft leading edge chord section; the three-dimensional woven preform includes an outer layer of three-dimensional woven fabric, an inner layer of three-dimensional woven fabric, and a sandwich material locked between the outer layer of three-dimensional woven fabric and the inner layer of three-dimensional woven fabric. The three-dimensional woven composite leading edge skin provided by the present invention has excellent anti-delamination and energy absorption capabilities, which solves the technical problems of high weight or easy damage between layers of traditional wing leading edge skin materials, and has strong bird strike resistance and a certain load-bearing capacity after impact, thereby effectively ensuring flight safety.

Description

Technical Field

[0001] The invention belongs to the technical field of wing manufacturing, and in particular relates to a three-dimensional woven sandwich composite aircraft leading edge skin and a manufacturing method thereof. Background Art

[0002] Currently, to meet strength requirements while achieving lightweight design, aircraft wing leading edges are typically manufactured from high-strength, lightweight composite materials, typically employing a sandwich structure. During an impact, the sandwich structure's panels constrain overall structural deformation, while the core material undergoes controlled compression deformation, absorbing most of the impact energy. This creates a highly efficient energy transfer and absorption mechanism, thereby enhancing the aircraft's structural safety.

[0003] The wing's leading edge is relatively thin and must meet aerodynamic shape accuracy, bending stiffness, and impact resistance requirements, which significantly limits its manufacturing methods. The current mainstream manufacturing process uses adhesive bonding technology, which involves bonding pre-cured laminated composite panels to the core material using adhesives.

[0004] However, in actual use, it was found that when traditional wing leading edge skin laminated composite materials were impacted after being formed, they were prone to various damages such as delamination between the front panel layers and debonding between the panel and the core layer, which led to failure of the sandwich structure wall panels, damage between the material structure layers, weak impact resistance, and inability to bear loads. Summary of the Invention

[0005] The purpose of the present invention is to provide a three-dimensional woven sandwich composite aircraft leading edge skin and a manufacturing method thereof. The three-dimensional woven preform and composite material for the aircraft leading edge skin provided by the present invention have excellent energy absorption capacity, excellent resistance to delamination and cracking, and solve the technical problems of traditional wing leading edge skin materials being heavy or easily damaged between layers. In addition, the material has strong bird strike resistance and has a certain load-bearing capacity after being impacted (such as a bird strike), thereby effectively ensuring flight safety.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a three-dimensional woven preform for an aircraft leading edge skin, the three-dimensional woven preform having an aircraft leading edge curved surface profiling structure; the three-dimensional woven preform is integrally woven, the warp yarn direction of the integrally woven preform being the same as the aircraft leading edge span direction, the warp yarns forming a plurality of warp yarn layers, and the warp yarns in each warp yarn layer being arranged along the curve profiling the chord-wise section of the aircraft leading edge;

[0008] The three-dimensional woven preform includes an outer three-dimensional woven fabric, an inner three-dimensional woven fabric, and a core material locked between the outer three-dimensional woven fabric and the inner three-dimensional woven fabric.

[0009] Preferably, the integrally woven warp yarns are divided into strands to lock the core material;

[0010] Or the integrally woven weft yarns are divided into strands to lock the core material;

[0011] Or the integrally woven warp yarns alternately enter the outer three-dimensional woven fabric and the inner three-dimensional woven fabric to lock the sandwich material.

[0012] Alternatively, the integrally woven weft yarns alternately enter the outer three-dimensional woven fabric and the inner three-dimensional woven fabric to lock the core material.

[0013] Preferably, the alternation of the warp yarns includes adjacent alternation or discontinuous alternation;

[0014] The alternation of the weft yarns includes adjacent alternation or discontinuous alternation.

[0015] Preferably, the integral weaving forming method includes a full thickness orthogonal form, an interlayer orthogonal form, a full thickness angle interlocking form or an interlayer angle interlocking form;

[0016] The integrated woven forming also uses Z-direction yarns, and the Z-direction yarns are selected from warp interlocking or weft interlocking.

[0017] Preferably, the ratio of the span length of the core material to the span length of the three-dimensional woven preform is 0.5-0.9:1;

[0018] The curvature of the core material conforms to the curvature of the leading edge of the aircraft.

[0019] Preferably, the sandwich material is a closed sandwich material.

[0020] The present invention provides a composite material for aircraft leading edge skin, comprising the three-dimensional woven preform for aircraft leading edge skin described in the above technical solution, and a cured resin composited with the three-dimensional woven preform for aircraft leading edge skin.

[0021] The present invention provides a method for preparing the composite material for the wing leading edge skin according to the above technical solution, comprising the following steps:

[0022] The three-dimensional woven preform is impregnated with a resin solution and then cured and formed to obtain the composite material for the aircraft leading edge skin.

[0023] Preferably, the curing molding method includes but is not limited to resin transfer molding or bag compression molding.

[0024] The present invention provides the use of the three-dimensional woven preform for aircraft leading edge skin described in the above technical solution, the composite material for aircraft leading edge skin described in the above technical solution, or the composite material for aircraft leading edge skin prepared by the preparation method described in the above technical solution in aircraft leading edge skin materials.

[0025] The present invention provides a three-dimensional woven preform for an aircraft leading edge skin, the preform having a curved surface-contouring structure. The preform is integrally woven, with the warp yarns oriented in the same direction as the span direction of the aircraft leading edge. The warp yarns are formed into multiple layers, with the warp yarns in each layer arranged along the curve of the chord-wise section of the aircraft leading edge. The preform comprises an outer three-dimensional woven fabric, an inner three-dimensional woven fabric, and a core material locked between the outer and inner three-dimensional woven fabrics. By designing the contoured structure of the preform and simultaneously weaving the outer and inner three-dimensional woven fabrics and the core material into an integral structure, the present invention effectively forms a stable three-dimensional network structure. This structure enables the preform to have excellent energy absorption capacity when subjected to impact, effectively dissipating and transmitting impact energy, and improving impact delamination, thereby enhancing the impact resistance of the aircraft leading edge and improving the aircraft's bird strike safety. At the same time, the present invention can absorb more impact energy when an impact occurs in the leading edge area of ​​the aircraft by locking the sandwich material structure between the outer three-dimensional woven fabric and the inner three-dimensional woven fabric, thereby improving the impact resistance of the leading edge of the aircraft and avoiding deformation and breakage. Finally, the present invention adopts an integrated weaving molding, which can effectively avoid microscopic damage or bending of fibers caused by secondary processing. In summary, the three-dimensional woven preform provided by the present invention has an integrated three-dimensional structure, excellent energy absorption capacity, anti-delamination ability and anti-cracking ability, which solves the technical problem that the layers of traditional wing leading edge skin materials are easily damaged, and has strong bird strike resistance and a certain load-bearing capacity after being impacted, thereby effectively ensuring flight safety.

[0026] Furthermore, in the present invention, the integrated woven fabric also utilizes Z-direction yarns, which are selected from interlocking warp or weft yarns. This Z-direction yarn enhances the layer connectivity of the three-dimensional woven preform in the thickness direction and locks the warp and weft yarns of each layer together, thereby avoiding the interfacial delamination and cracking problems of traditional laminated composites and improving the composite's resistance to delamination and cracking.

[0027] The present invention provides a composite material for wing leading edge skins, comprising the three-dimensional woven preform for aircraft leading edge skins described in the above technical solution, and a cured resin composited with the three-dimensional woven preform for aircraft leading edge skins. The composite material provided by the present invention exhibits excellent energy absorption and delamination resistance, addressing the interlaminar failure issues associated with traditional materials. Furthermore, the composite material maintains a certain load-bearing capacity after impact, ensuring flight safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the chord-wise cross section of a three-dimensional woven preform for an aircraft leading edge skin, showing two warp yarn layers and three weft yarn layers in full-thickness orthogonal form (Z-direction yarns omitted). Figure 1 The left picture is a schematic diagram of the chordal section of the area without core material. Figure 1 The right picture is a schematic diagram of the chordal section of the core material area;

[0029] Figure 2 The chord-wise cross-section of a three-dimensional woven preform for aircraft leading edge skin, with two warp yarn layers and three weft yarn layers in full-thickness orthogonal form, and its partial enlargement, Figure 2 (a) in the figure is the direction of the weft yarn in the form of weft yarn strands. Figure 2 (b) and Figure 2 (c) shows two weft yarn directions in which the weft yarns alternately enter the inner and outer layers;

[0030] Figure 3 The spanwise cross-section diagram and partial magnification of the leading edge point of a three-dimensional woven preform for aircraft leading edge skin, which shows two warp yarn layers and three weft yarn layers in full-thickness orthogonal form, Figure 3 (a) in the figure is the direction of the Z-direction yarn in the form of Z-direction yarn splitting. Figure 3 (b) and Figure 3 (c) shows two Z-direction yarn directions in the form of alternating interlocking inner and outer layers of Z-direction yarns;

[0031] Figure 4 is a cross-sectional view of the sandwich material. Figure 4 The upper figure is the cross-sectional view of the core material at the leading edge. Figure 4 The lower figure in the figure is a chord-wise cross-section of the sandwich material;

[0032] Figure 5 Schematic diagram of the integrated weaving of a three-dimensional woven preform for aircraft leading edge skin;

[0033] Figure 6 Molds used for resin transfer molding;

[0034] In the figure: 1 is weft yarn, 2 is warp yarn, 3 is core material, 4 is Z-direction yarn, 5 is inner mold, and 6 is outer mold. DETAILED DESCRIPTION

[0035] The present invention provides a three-dimensional woven preform for an aircraft leading edge skin, the three-dimensional woven preform having an aircraft leading edge curved surface profiling structure; the three-dimensional woven preform is integrally woven, the warp yarn direction of the integrally woven preform being the same as the aircraft leading edge span direction, the warp yarns forming a plurality of warp yarn layers, and the warp yarns in each warp yarn layer being arranged along the curve profiling the chord-wise section of the aircraft leading edge;

[0036] The three-dimensional woven preform includes an outer three-dimensional woven fabric, an inner three-dimensional woven fabric, and a core material locked between the outer three-dimensional woven fabric and the inner three-dimensional woven fabric.

[0037] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0038] The three-dimensional woven preform for aircraft leading edge skin provided by the present invention has an aircraft leading edge curved surface profiling structure. The three-dimensional woven preform provided by the present invention directly obtains an aircraft leading edge curved surface profiling shape through integral weaving molding.

[0039] In the present invention, the aircraft leading edge preferably comprises a wing leading edge or a tail leading edge. The wing leading edge preferably comprises a general wing leading edge or a slat or a leading edge flap.

[0040] The three-dimensional woven preform for aircraft leading edge skin provided by the present invention comprises an outer three-dimensional woven fabric, an inner three-dimensional woven fabric, and a sandwich material locked between the outer three-dimensional woven fabric and the inner three-dimensional woven fabric.

[0041] The three-dimensional woven preform for aircraft leading edge skin provided by the present invention is woven and formed in one piece, that is, the outer three-dimensional woven fabric, the inner three-dimensional woven fabric and the sandwich material of the three-dimensional woven preform are woven and formed in one piece.

[0042] In the present invention, the yarns used for the integral weaving formation include warp yarns and weft yarns.

[0043] In the present invention, the direction of the integrally woven warp yarn is the same as the span direction of the aircraft leading edge, the warp yarn forms multiple warp yarn layers, and the warp yarns in each warp yarn layer are arranged along the curve of the chord-wise section of the aircraft leading edge.

[0044] In the present invention, the integrally woven weft yarn is preferably divided into strands to lock the core material. Alternatively, the integrally woven weft yarn preferably alternates between the outer and inner three-dimensional woven fabric layers to lock the core material. The split strands are preferably one strand divided into two. The present invention does not specifically limit the alternation of the weft yarns; either continuous or discontinuous alternation can be employed to ensure locking of the core material.

[0045] Alternatively, in the present invention, the integrally woven warp yarns are preferably split into strands to lock the core material. Alternatively, the integrally woven warp yarns are preferably alternately fed into the outer and inner three-dimensional woven fabric layers to lock the core material. The split strands are preferably one strand divided into two. The present invention has no particular limitation on the alternation of the warp yarns; either continuous or discontinuous alternation can be employed to ensure locking of the core material.

[0046] Figure 1 Schematic diagram of the chord-wise cross section of a three-dimensional woven preform for aircraft leading edge skin, showing two warp yarn layers and three weft yarn layers in full-thickness orthogonal form. Figure 1 The Z-direction yarn is omitted. Figure 1 As shown in the left figure, in the area without core material, the outer three-dimensional woven fabric and the inner three-dimensional woven fabric are closed. In the present invention, the direction of the warp yarn 2 is the same as the span direction of the leading edge of the aircraft, and the warp yarn 2 forms The warp yarns 2 in each warp yarn layer are arranged along the curve of the chord section of the leading edge of the aircraft, and the weft yarns 1 form There are two weft yarn layers, and one warp yarn layer is inserted between two adjacent weft yarn layers.

[0047] Figure 2 The chord-wise cross-section of a three-dimensional woven preform for aircraft leading edge skin, with two warp yarn layers and three weft yarn layers in full-thickness orthogonal form, and its partial enlargement, Figure 2 The Z-direction yarn is omitted. Figure 2 (a) in the figure is the direction of the weft yarn in the form of weft yarn strands. Figure 2 (b) and Figure 2 (c) shows two weft yarn directions in which the weft yarns alternately enter the outer three-dimensional woven fabric and the inner three-dimensional woven fabric: Figure 2 (b) is the weft yarn entering the outer three-dimensional woven fabric. Figure 2 (c) shows the weft yarn entering the inner layer of the three-dimensional woven fabric.

[0048] As one or more embodiments of the present invention, the weft yarn layers formed by the weft yarns 1 of the three-dimensional woven preform are numbered from outside to inside in the thickness direction. ~ There are two ways to lock the core material:

[0049] Method 1: Weft yarn splitting method, specifically, numbered The weft yarn in the weft yarn layer consists of two strands of yarn and composition, before locking the sandwich material, and After being combined into one strand and reaching the position of the core material, The outer three-dimensional woven fabric of the three-dimensional woven preform (ultimately forming the outer skin) is formed by the warp and weft yarns outside it. The inner three-dimensional woven fabric of the three-dimensional woven preform (ultimately forming the inner skin) is composed of the warp and weft yarns therein. The weft yarn layer, 2~ is acceptable Any value in . Figure 2 (a) in the figure shows a partially enlarged schematic diagram of the weft yarn using method 1.

[0050] Method 2: Alternating weft yarns: After reaching the position of the core material, one weft yarn Entering the outer three-dimensional fabric, another weft yarn Entering the inner three-dimensional fabric, the corresponding warp and weft yarns respectively form the outer three-dimensional woven fabric and the inner three-dimensional woven fabric of the three-dimensional woven preform. The two weft yarns are alternately distributed along the span direction, and the alternation mode can be selected as continuous alternation or discontinuous alternation. The weft yarn layer, 2~ is acceptable Any value in . Figure 2 (b) and (c) show the partially enlarged schematic diagrams of the weft yarn using method 2.

[0051] In the present invention, the integral weaving forming method preferably includes a full-thickness orthogonal form, an inter-layer orthogonal form, a full-thickness angle interlocking form or an inter-layer angle interlocking form.

[0052] In the present invention, the one-piece woven shape preferably further uses Z-direction yarns, and the Z-direction yarns are preferably selected from interlocking warp yarns or interlocking weft yarns.

[0053] Figure 3 The spanwise cross-section diagram and partial magnification of the leading edge point of a three-dimensional woven preform for aircraft leading edge skin, which shows two warp yarn layers and three weft yarn layers in full-thickness orthogonal form, Figure 3 (a) in the figure is the direction of the Z-direction yarn in the form of 4 strands. Figure 3 (b) and Figure 3 (c) shows two directions of the Z-direction yarn 4 in the form of alternating interlocking inner and outer layers of the Z-direction yarn 4: Figure 3 (b) is a three-dimensional woven fabric with 4 interlocking outer layers of Z-direction yarns. Figure 3 (c) is a three-dimensional woven fabric with 4 interlocking inner layers of Z-direction yarns.

[0054] In the present invention, Figure 3 Take the warp interlocking of the Z-direction yarn 4 as an example. The Z-direction yarn 4 passing through the sandwich material can be selected in the form of warp interlocking or weft interlocking. The interweaving method of the Z-direction yarn 4 preferably includes the following two methods:

[0055] Method 1: Z-direction yarn consists of two strands of yarn and Before reaching the core material position, the two strands of Z-direction yarn are combined into one strand and woven together. When reaching the edge of the core material position area, and separate, As the outer layer of the three-dimensional woven fabric (ultimately forming the outer skin) of the three-dimensional woven preform, the Z-direction yarn As the Z-direction yarn of the inner layer of the three-dimensional woven fabric (ultimately forming the inner skin) of the three-dimensional woven preform. Figure 3 (a) in the figure shows a partially enlarged schematic diagram of the Z-direction yarn using method 1.

[0056] Method 2: The Z-direction yarn is composed of a strand of yarn. After reaching the core material area, one Z-direction yarn interlocks the inner 3D woven fabric of the 3D woven preform (ultimately forming the inner skin), and the other Z-direction yarn interlocks the outer 3D woven fabric of the 3D woven preform (ultimately forming the outer skin). The two interweaving methods are alternately distributed. Figure 3 (b) and (c) in the figure show the partially enlarged schematic diagrams of two bundles of Z-direction yarns using the second method.

[0057] Figure 4 is a cross-sectional view of the sandwich material. Figure 4 The upper figure is the spanwise fracture section of the sandwich material at the leading edge point. Figure 4 The figure below shows a chord-wise cross section of the sandwich material.

[0058] In the present invention, the ratio of the span length of the core material to the span length of the three-dimensional woven preform is preferably 0.5-0.9:1, more preferably 0.6-0.8:1, and in an embodiment, can be 0.7:1. In the present invention, the ratio of the span length of the core material to the span length of the three-dimensional woven preform is controlled to prevent the core material from leaking.

[0059] In one or more embodiments of the present invention, the span length of the three-dimensional woven preform is L. During the weaving process of the three-dimensional woven preform, the three-dimensional woven fabric is separated at a position at least 0.05L away from the edge of the three-dimensional woven preform, and the sandwich material is placed in it, and the three-dimensional woven fabric is reassembled at a position at least 0.05L away from the edge of the other side.

[0060] In the present invention, the curvature of the core material preferably conforms to the curvature of the aircraft leading edge. The spanwise cross-sectional shape of the core material is preferably quadrilateral, which may be rectangular or wedge-shaped. The wedge-shaped spanwise cross-sectional shape of the core material can avoid the formation of resin-rich areas during subsequent curing of the resin material.

[0061] In the present invention, the thickness of the sandwich material is preferably 2 to 50 mm. The chord-wise cross-sectional shape and size of the sandwich material are determined according to the specific shape of the leading edge of the aircraft.

[0062] In the present invention, the height of the sandwich material is the straight-line distance between the starting point and the end point of the sandwich material, perpendicular to the wing chord formed by the leading edge of the aircraft.

[0063] The maximum height of the leading edge of the aircraft is the maximum distance between the upper and lower surfaces of the leading edge of the aircraft and the wing chord line formed perpendicular to the leading edge of the aircraft.

[0064] In the present invention, the height of the sandwich material is preferably ≥ 20% of the maximum height of the aircraft's leading edge. By controlling the height of the sandwich material to preferably ≥ 20% of the maximum height of the aircraft's leading edge, the present invention can reduce structural weight while ensuring that the impact surface of the aircraft's leading edge has sufficient material to absorb impact energy.

[0065] In the present invention, the sandwich material is preferably a closed core material, and preferably includes one or more of a foam sandwich material, a honeycomb sandwich material, and a grid sandwich material.

[0066] Figure 5 The present invention provides a method for weaving a three-dimensional woven preform for an aircraft leading edge skin according to the above technical solution, comprising the following steps:

[0067] The three-dimensional woven preform for the aircraft leading edge skin is obtained by weaving with yarns, wherein the core material is locked during the weaving process. The yarns include warp yarns and weft yarns, or the yarns include warp yarns, weft yarns and Z-direction yarns.

[0068] As one or more embodiments of the present invention, a specific weaving method of the three-dimensional woven preform includes: weaving the warp yarns and the weft yarns, and locking the core material during the weaving process.

[0069] As one or more embodiments of the present invention, a specific weaving method of the three-dimensional woven preform includes: weaving the warp yarns, weft yarns and Z-direction yarns, and locking the core material during the weaving process.

[0070] The interweaving method of the Z-direction yarn preferably includes the following two forms:

[0071] Method 1: Z-direction yarn consists of two strands of yarn and Before reaching the core material position, the two strands of Z-direction yarn are combined into one strand and woven together. When reaching the edge of the core material position area, and separate, As the outer layer of the three-dimensional woven fabric (ultimately forming the outer skin) of the three-dimensional woven preform, the Z-direction yarn As the Z-direction yarn of the inner layer of the three-dimensional woven fabric (ultimately forming the inner skin) of the three-dimensional woven preform. Figure 3 (a) in the figure shows a partially enlarged schematic diagram of the Z-direction yarn using method 1.

[0072] Method 2: The Z-direction yarn is composed of a strand of yarn. After reaching the core material area, one Z-direction yarn interlocks the inner 3D woven fabric of the 3D woven preform (ultimately forming the inner skin), and the other Z-direction yarn interlocks the outer 3D woven fabric of the 3D woven preform (ultimately forming the outer skin). The two interweaving methods are alternately distributed. Figure 3 (b) and (c) in the figure show the partially enlarged schematic diagrams of two bundles of Z-direction yarns using the second method.

[0073] The present invention provides a composite material for aircraft leading edge skins, comprising the three-dimensional woven preform described in the above technical solution and a curing resin composited with the three-dimensional woven preform. The present invention has no particular requirements for the specific type of the curing resin.

[0074] The present invention provides a method for preparing the composite material for the wing leading edge skin according to the above technical solution, comprising the following steps:

[0075] The three-dimensional woven preform is impregnated with a resin solution and then cured and formed to obtain the three-dimensional woven composite material for the aircraft leading edge skin.

[0076] In the present invention, the curing molding method preferably includes resin transfer molding (RTM) molding or bag compression molding. Figure 6 The molding die used in resin transfer molding preferably includes an inner mold 5 and an outer mold 6. The molding die used in bag compression molding preferably includes an outer mold 6. The bag compression molding preferably also uses vacuum bag wrapping support molding.

[0077] In the present invention, the bag compression molding preferably uses only the outer mold 6 as described in 6, and the inner side is supported by vacuum bag wrapping.

[0078] In the present invention, the inner mold 5 and the outer mold 6 preferably have an aircraft leading edge curved surface profiling structure.

[0079] In the present invention, the curing molding preferably uses an outer mold to ensure the smoothness and flatness of the outer side of the obtained three-dimensional woven composite material. The inner mold is optional depending on the curing method.

[0080] In the present invention, the resin transfer molding method adopts Figure 6The molding die preferably comprises an inner mold 5 and an outer mold 6. The resin transfer molding method preferably comprises the following steps: placing the three-dimensional woven preform into the molding die; preheating the mold and resin system until the mold and resin have uniform temperatures; connecting the resin transfer molding device and checking for airtightness; mixing the resin components, vacuum defoaming, and pouring the mixture into the liquid storage device; injecting the resin, and when there are no obvious bubbles at the overflow port, first closing the feed valve and then closing the overflow valve; and transferring the mold after resin infusion to an oven for curing.

[0081] In the present invention, the bag pressing method is as follows Figure 6 The bagging method specifically includes: wiping the outer mold 6 and applying a release agent on the outer mold 6; combining and bagging the three-dimensional woven preform and auxiliary materials such as an isolation film and breathable felt on the outer mold 6; pasting sealing strips, laying vacuum bag film, installing the guide tube and resin tube; testing air tightness and vacuum degree; evacuating the vacuum, introducing resin; and transferring to an oven for curing.

[0082] The present invention provides the use of the three-dimensional woven preform for aircraft leading edge skin described in the above technical solution, the composite material for aircraft leading edge skin described in the above technical solution, or the composite material for aircraft leading edge skin prepared by the preparation method described in the above technical solution in aircraft leading edge skin materials.

[0083] In the present invention, the aircraft leading edge preferably comprises a wing leading edge or a tail leading edge. The wing leading edge preferably comprises a general wing leading edge or a slat or a leading edge flap.

[0084] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0085] Example 1

[0086] In this example, a 3D woven composite wing leading edge skin of a NACA 0015 airfoil was prepared. The wing chord length was 1000 mm, the maximum height was 150 mm, the chord length of the wing leading edge skin was 150 mm, and the span of the upper and lower wing leading edge skins was 200 mm. The span of the sandwich material was 140 mm, and the sandwich material was a closed-cell foam material. The design thickness of the leading edge skin material was 4 mm, and the thickness of the warp yarn layer and the thickness of the weft yarn layer were 200 mm. :

[0087] The specific weaving method of the three-dimensional woven preform in this embodiment includes:

[0088] The number of warp yarn layers in the area without core material is , the warp material is Toray T700-12k, numbered from outside to inside ~ ; Number of weft yarn layers , the weft material is Toray T700-12k, numbered from outside to inside ~ .in Two strands of yarn and Composition (total number of monofilaments is 24k). In the range of 30mm~170mm along the span direction, With weft yarn ~ and warp ~ The outer skin that makes up the wing leading edge skin has an outer layer of three-dimensional woven fabric with a thickness of 2.565mm; With weft yarn ~ and warp ~ The inner skin that makes up the leading edge of the wing has an inner layer of three-dimensional woven fabric with a thickness of 1.425mm.

[0089] Arrange the warp yarns in the shape of the leading edge of the NACA 0015 airfoil and weave them in the form of interlocking angles between layers. and Separate, in and Put the foam sandwich material between them. Continue weaving to 170mm. and Rejoin them into one strand until the weaving is complete.

[0090] The curing and molding method of the three-dimensional woven composite material in this embodiment includes:

[0091] A resin transfer molding vacuum infusion process was used: (I) preheat the assembled mold and resin system (brand IN2) at 45°C until the mold and resin temperatures were uniform; (II) connect the liquid reservoir, mold, resin storage tank, and vacuum pump, and check for airtightness; (III) mix the resin components, defoam under vacuum, and pour into the resin storage tank; (IV) close the feed valve, open the vacuum pump, and the overflow valve until the vacuum level in the mold is greater than 0.99; (V) slowly open the feed valve and inject the resin. When there are no visible bubbles in the overflow, close the feed valve first, then the overflow valve; (VI) transfer the mold after resin infusion to an oven and heat at 100°C for 3 hours. (VII) close the oven, allow the mold to cool naturally to room temperature, and then open the mold.

[0092] From the above embodiments, it can be seen that the composite material for aircraft leading edge skin provided by the present invention has the following advantages:

[0093] Excellent resistance to delamination and cracking. The Z-direction yarns of 3D woven fabrics strengthen the fabric through the thickness and lock the weft yarns of each layer together, avoiding the interfacial delamination and cracking problems faced by traditional laminated composites.

[0094] Excellent impact resistance. 3D woven composites feature a three-dimensional reinforcement structure, with fibers interwoven in three dimensions to form a stable network. This structure enables 3D woven composites to effectively disperse and transfer impact energy when impacted, thereby improving the wing's impact resistance and enhancing the aircraft's bird strike safety.

[0095] Highly designable. The arrangement and interweaving of three-dimensional woven fabric yarns can be precisely controlled to optimize the mechanical properties of the material, including impact resistance.

[0096] Avoiding fiber bundle bending damage. Compared to traditional wing leading edge designs, which first form a plate structure and then impart the desired curvature through secondary processing methods such as bending and forming, this method prefabricates the three-dimensional fabric curvature, achieving integrated molding of the material shape and structure during the weaving stage. This avoids microscopic fiber bending and damage caused by secondary processing.

[0097] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A three-dimensional woven preform for an aircraft leading edge skin, characterized in that: The three-dimensional woven preform has a structure that is shaped like the curved surface of the leading edge of an aircraft; the three-dimensional woven preform is integrally woven, the warp direction of the integrally woven preform is the same as the span direction of the leading edge of the aircraft, the warp yarns form a plurality of warp yarn layers, and the warp yarns in each warp yarn layer are arranged along the curve of the chord-wise section of the leading edge of the aircraft; The three-dimensional woven preform includes an outer three-dimensional woven fabric, an inner three-dimensional woven fabric, and a core material locked between the outer three-dimensional woven fabric and the inner three-dimensional woven fabric, wherein the ratio of the span length of the core material to the span length of the three-dimensional woven preform is 0.5-0.9:1; the height of the core material is ≥ 20% of the maximum height of the leading edge of the aircraft; and the curvature of the core material is contoured to the curvature of the leading edge of the aircraft; The weft yarn layers formed by the weft yarns of the three-dimensional woven preform are numbered from outside to inside along the thickness direction. ~ , locking the sandwich material or including the following two methods: Method 1: Weft yarn splitting method, specifically, numbered The weft yarn in the weft yarn layer consists of two strands of yarn and composition, before locking the sandwich material, and After being combined into one strand and reaching the position of the core material, The outer three-dimensional woven fabric of the three-dimensional woven preform is composed of the warp and weft yarns outside the three-dimensional woven preform. The inner three-dimensional woven fabric of the three-dimensional woven preform is composed of the warp and weft yarns therein, and the number is The weft yarn layer, 2~ is acceptable Any value in ; Method 2: Alternating weft yarns: After reaching the position of the core material, one weft yarn Entering the outer three-dimensional fabric, another weft yarn Entering the inner three-dimensional fabric, the outer three-dimensional woven fabric and the inner three-dimensional woven fabric of the three-dimensional woven preform are formed with the corresponding warp and weft yarns respectively. The two weft yarns are alternately distributed along the span direction. The alternation mode can be selected as continuous alternation or discontinuous alternation. The number is The weft yarn layer, 2~ is acceptable Any value in ; The integrated woven shape further uses Z-direction yarns, which are warp interlocking or weft interlocking. The interweaving method of the Z-direction yarns may include the following two methods: Method 1: Z-direction yarn consists of two strands of yarn and Before reaching the core material position, the two strands of Z-direction yarn are combined into one strand and woven together, and then reach the edge of the core material position area. and separate, As the Z-direction yarn of the outer layer of the three-dimensional woven fabric of the three-dimensional woven preform, Z-directional yarns as an inner layer of a three-dimensional woven fabric of a three-dimensional woven preform; Method 2: The Z-direction yarn is composed of a strand of yarn. After reaching the core material position area, one Z-direction yarn interlocks the inner three-dimensional woven fabric of the three-dimensional woven preform, and the other Z-direction yarn interlocks the outer three-dimensional woven fabric of the three-dimensional woven preform. The two interweaving methods are alternately distributed.

2. The three-dimensional woven preform for aircraft leading edge skin according to claim 1, characterized in that: The alternation of the warp yarns includes adjacent alternation or discontinuous alternation; The alternation of the weft yarns includes adjacent alternation or discontinuous alternation.

3. The three-dimensional woven preform for aircraft leading edge skin according to claim 1 or 2, characterized in that: The integral weaving forming method includes a full-thickness orthogonal form, an inter-layer orthogonal form, a full-thickness angle interlocking form or an inter-layer angle interlocking form.

4. The three-dimensional woven preform for aircraft leading edge skin according to claim 1, characterized in that: The sandwich material is a closed sandwich material.

5. A composite material for aircraft leading edge skin, characterized in that: The invention comprises the three-dimensional woven preform for aircraft leading edge skin according to any one of claims 1 to 4, and a cured resin compounded with the three-dimensional woven preform for aircraft leading edge skin.

6. The method for preparing the composite material for the wing leading edge skin according to claim 5, characterized in that: The following steps are involved: The three-dimensional woven preform is impregnated with a resin solution and then cured and formed to obtain the composite material for the wing leading edge skin.

7. The preparation method according to claim 6, characterized in that The curing molding method includes but is not limited to resin transfer molding or bag compression molding.

8. Use of the three-dimensional woven preform for aircraft leading edge skin according to any one of claims 1 to 4, the composite material for aircraft leading edge skin according to claim 5, or the composite material for aircraft leading edge skin prepared by the preparation method according to claim 6 or 7 in aircraft leading edge skin materials.

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