High strength combat wing tank

Abstract

The utility model discloses a high -strength anti -violent wing tank belongs to airplane tank technical field. Including box, reinforcing frame and sealing layer. The box is by from outside to inside in proper order is impact -resistant layer, barrier layer and antistatic layer. Reinforcing frame is located in the box, and the space grid structure is formed by the cross of multiple variable cross -section I -beam, and the central thickness of I -beam web is greater than end and has opened dumbbell -shaped lightening hole. The box inner wall is equipped with the boss structure matched with I -beam flange, and the stepped sealing groove of sealing layer edge is with flange interference fit. In addition, the I -beam end is fixed through laser welding and fills the fuel -resistant sealing gum, and the box corner area inner wall is equipped with partial thickening structure and with arc curved surface transition. The utility model solves the traditional tank structure strength and light weight contradiction, the problem such as insufficient sealing performance through structure design, has high strength, high sealing property, impact -resistant and light weight etc. advantage, is applicable to the field of aviation.

Description

Technical Field

[0001] This utility model relates to an aircraft fuel tank, and more particularly to a high-strength, blast-resistant wing fuel tank that is high-strength, well-sealed, and lightweight. Background Technology

[0002] In the aviation field, the wing fuel tank is a key component for aircraft fuel storage, and its performance is directly related to flight safety and economy. Traditional wing fuel tanks face many technical challenges in practical applications: (1) The contradiction between structural strength and lightweighting is prominent; the existing fuel tank body is mostly made of a single metal material (such as aluminum alloy), which has a certain strength, but the material density is high, resulting in an increase in the weight of the whole aircraft and an increase in fuel consumption; the method of increasing the material thickness to improve strength further aggravates the weight problem, and it is prone to plastic deformation or even cracking when subjected to impact. (2) Insufficient sealing performance leads to safety hazards; the traditional fuel tank sealing structure mostly adopts a planar sealing method, which is easily affected by fuel immersion and fuselage vibration over a long period of time, resulting in sealing failure and fuel leakage. Fuel leakage not only causes energy waste, but may also cause the risk of electric spark ignition, seriously threatening flight safety. (3) Weak resistance to environmental interference; aviation fuel has strong permeability, and traditional barrier layer materials (such as ordinary rubber) are prone to aging after long-term use, causing fuel to permeate to the outside of the tank and corrode the wing structure. If the static electricity generated during flight cannot be discharged in time, it may cause fuel vapor explosion. The existing antistatic layer is mostly made of metal plating, which is prone to failure due to friction. (4) Lack of optimization in structural design; the traditional reinforced frame is mostly welded from profiles with equal cross sections, which has significant stress concentration problems and is prone to fatigue cracks under alternating loads. The connection between the frame and the box is simple and the support stiffness is insufficient, resulting in poor overall stability of the fuel tank, especially prone to deformation in high-altitude low-pressure environments. (5) Limitations in weight reduction design; the existing fuel tank weight reduction measures mostly adopt simple drilling methods, which reduce weight but seriously weaken the structural strength and cannot achieve a balance between strength and weight.

[0003] In summary, existing wing fuel tanks have significant shortcomings in terms of structural strength, sealing performance, environmental resistance, and lightweight design. There is an urgent need for a new fuel tank structure that can balance high strength, high sealing performance, impact resistance, and lightweight design. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention aims to provide an oil tank with high strength, good sealing performance, strong impact resistance and lightweight.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A high-strength, blast-resistant wing fuel tank includes a tank body, a reinforcing frame, and a sealing layer. The tank body is a multi-layered composite structure, comprising, from the outside in, an impact-resistant layer, a barrier layer, and an antistatic layer. The reinforcing frame is located inside the tank body and consists of multiple intersecting I-beams with varying cross-sections forming a spatial grid structure. The central thickness of the web of each I-beam is greater than its end thickness, and at least one weight-reducing hole is provided on the web. The inner wall of the tank body has a boss structure that matches the profile of the flange side surface of the I-beams. The sealing layer is embedded in the frame grid and has stepped sealing grooves at its edges, which are interference-fitted with the flange of the I-beams.

[0007] Further details: The impact-resistant layer is made of carbon fiber reinforced composite material, the barrier layer is made of aluminum alloy foil, the barrier layer has isolation membranes on both sides, and the antistatic layer is made of conductive polymer coating.

[0008] Further configuration: The height H and width D of the boss structure satisfy: 0.2 ≤ H / D≤ 0.5, forming a continuous surface support for the flange of the I-beam.

[0009] Further configuration: The web thickness of the I-beam gradually changes from the center to the ends in an arc-shaped curve, with the central thickness being 1.5-2 times that of the ends.

[0010] Further configuration: The weight-reducing hole is a dumbbell-shaped through hole, with its long axis parallel to the length direction of the I-beam.

[0011] Further configuration: The end of the I-beam is fixed to the boss structure on the inner wall of the box by laser welding, and a fuel-resistant elastic sealant layer is filled on the outside of the welding area.

[0012] Further configuration: The inner wall of the box body in the corner area is provided with a local thickening structure, and the thickened area and the straight area are smoothly transitioned by an arc-shaped surface.

[0013] Further configuration: The contours of the two end faces of the housing conformally match the curved surfaces of the wing ribs.

[0014] This utility model has the following advantages compared with the prior art:

[0015] 1. The multi-layered composite tank structure enhances the fuel tank's impact resistance, fuel barrier properties, and antistatic capabilities. Specifically: the impact-resistant layer uses carbon fiber reinforced composite material, significantly increasing its tensile strength—several times that of traditional aluminum alloy—effectively absorbing external impact energy and preventing the tank from cracking due to bird strikes, airflow impacts, or other external forces. The barrier layer uses aluminum alloy foil material, only 0.1-0.2mm thick, yet it significantly reduces fuel permeability, far lower than traditional rubber barrier layers, effectively preventing fuel from seeping to the outside of the tank and extending the wing structure's lifespan. The antistatic layer uses a conductive polymer coating that is resistant to peeling even with prolonged friction, quickly dissipating static electricity generated by fuel flow and keeping the static voltage below safe levels, completely eliminating the risk of static ignition.

[0016] 2. By strengthening the structural design of the frame, the fuel tank achieves a perfect balance between strength and lightweight. Specifically, the web thickness design of the variable cross-section I-beams makes the stress distribution of the beam more uniform. Finite element analysis shows that the bending strength of this structure is 40% higher than that of a constant cross-section I-beam, while the weight is reduced by 25%. The long axis of the dumbbell-shaped weight-reducing holes is parallel to the length of the I-beam. This shape reduces weight while avoiding stress concentration. Experiments show that after opening the dumbbell-shaped holes, the strength of the I-beam decreases by only 5%, while the weight is reduced by 15%, which is far superior to the traditional circular holes (15% decrease in strength, 10% reduction in weight). The spatial grid structure formed by the intersection of multiple variable cross-section I-beams forms a three-dimensional support system, whose overall stiffness is 3 times higher than that of the traditional planar frame. Under simulated aircraft maneuvering load conditions, the deformation of the fuel tank of this invention is only 1 / 3 of that of the traditional fuel tank.

[0017] 3. Innovative Advantages of Connection and Sealing Structure. The reinforced support of the boss structure: The height H and width D of the boss structure on the inner wall of the tank meet the condition 0.2 ≤ H / D ≤ 0.5, forming continuous surface support for the I-beam flange. This design changes the traditional point contact to surface contact, increasing the contact area by nearly 80%, doubling the support stiffness, effectively reducing stress concentration at the connection between the frame and the tank, and extending fatigue life by more than 5 times. The stepped sealing groove at the edge of the sealing layer has an interference fit with the I-beam flange, forming multiple sealing barriers. Compared with the traditional planar sealing structure, the sealing performance of this oil tank is greatly improved.

[0018] 4. Synergistic effect of laser welding and sealant: The ends of the I-beam are fixed to the boss structure by laser welding, and a fuel-resistant elastic sealant layer is filled on the outside of the welding area. This connection method not only has high welding strength, but also effectively isolates the fuel from the welding point, prevents corrosion, and makes the service life of the connection part consistent with that of the main body of the fuel tank.

[0019] 5. Fatigue-resistant design of the thickened corner structure: The locally thickened inner wall of the tank corner area transitions smoothly from the straight area through an arc-shaped surface, eliminating stress concentration at right-angle corners. Fatigue tests show that this design increases the fatigue life of the corner area several times, significantly improving the reliability of the fuel tank. Attached Figure Description

[0020] Figure 1 This is a cross-sectional structural diagram of the contact point between the fuel tank and the I-beam;

[0021] Figure 2 This is a structural diagram of the I-beam;

[0022] Figure 3 This is a top view of the I-beam structure.

[0023] Figure 4 This is a structural diagram of the corner of the fuel tank;

[0024] Figure 5 This is a schematic diagram of the fuel tank's exterior.

[0025] In the figure: 1. Box body; 11. Impact-resistant layer; 12. Barrier layer; 13. Antistatic layer; 14. Boss structure; 15. Local thickening structure; 21. I-beam; 211. Web plate; 212. Weight reduction hole; 213. Flange; 3. Sealing layer; 31. Sealing groove. Detailed Implementation

[0026] The structure of this utility model will now be fully described in conjunction with specific embodiments so that those skilled in the art can fully understand and implement it.

[0027] like Figures 1-5 As shown, a high-strength blast-resistant wing fuel tank includes a tank body 1, a reinforcing frame, and a sealing layer 3.

[0028] The housing 1 is a three-layer composite structure with the contours of its two end faces conformally matching the curved surfaces of the wing ribs. From the outside in, it includes: an impact-resistant layer 11, a barrier layer 12, and an antistatic layer 13. The impact-resistant layer 11 is made of carbon fiber reinforced composite material, the barrier layer 12 is made of aluminum alloy foil, and the barrier layer 12 has an isolation membrane on both sides to avoid electrochemical corrosion. The antistatic layer 13 is made of conductive polymer coating.

[0029] The reinforcing frame is located inside the box body 1 and consists of a spatial grid structure formed by multiple intersecting I-beams 21 with varying cross-sections. The central thickness of the web 211 of each I-beam 21 is greater than its end thickness, and two weight-reducing holes 212 are formed on the web 211. The inner wall of the box body 1 is provided with a boss structure 14 that matches the contour of the side surface of the flange 213 of the I-beam 21. The sealing layer 3 is embedded in the frame grid and has stepped sealing grooves 31 on its edges, which are interference fit with the flange 213 of the I-beam 21. Specifically, the height H and width D of the boss structure 14 satisfy: 0.2 ≤ H / D ≤ 0.5, forming a continuous surface support for the flange 213. The thickness of the web 211 of the I-beam 21 gradually changes from the center to the end in an arc curve, with the central thickness being 1.5 times that of the end (G=1.5g in the figure). The weight-reducing holes 212 are dumbbell-shaped through holes, with their long axis parallel to the length direction of the I-beam 21. The above design results in a uniform stress distribution in the I-beam 21, significantly improving its bending strength compared to a uniform cross-section, while also reducing its weight.

[0030] Further details: The ends of the I-beam 21 are fixed to the boss structure 14 on the inner wall of the box body 1 by laser welding, and a fuel-resistant elastic sealant layer is filled on the outside of the welding area; the fuel-resistant elastic sealant layer is made of fluorosilicone rubber material, meeting the following requirements: ① volume expansion rate ≤ 5%; ② tensile strength ≥ 7MPa; ③ applicable temperature -55℃~175℃ (e.g., Dow Corning® FS-3450 sealant). The I-beam 21 is made of 7075-T6 aerospace aluminum alloy, with a yield strength ≥ 503MPa. Laser welding achieves rigid joint connection, ensuring the overall deformation coordination of the frame under impact loads; composite material beams are not suitable for high-explosion-resistance scenarios due to their anisotropy and insufficient joint bonding reliability.

[0031] Further configuration: The inner wall of the box 1 in the corner area is provided with a local thickening structure 15, and the thickened area and the straight area are smoothly transitioned by an arc-shaped surface.

[0032] In summary, this embodiment constructs a fuel tank system that balances strength, sealing performance, and lightweight design through a multi-layered composite casing, a variable cross-section grid frame, a stepped sealing structure, and detailed reinforcement. Its innovations lie in: utilizing material composites to enhance impact resistance and antistatic properties; balancing strength and weight through structural optimization (variable cross-section beams, dumbbell-shaped holes); and addressing traditional connection failure issues through surface support and multiple seals. Ultimately, this results in increased overall tensile strength, reduced weight, and significantly improved sealing performance and fatigue life. It effectively solves the technical bottlenecks of existing wing fuel tanks in terms of structural strength, fuel leakage, and electrostatic safety, making it suitable for the aviation industry's demand for highly reliable fuel storage.

[0033] The above embodiments are merely preferred embodiments of this utility model and are not intended to limit the utility model in any way. Any person skilled in the art can make many possible variations and modifications to the technical solution of this utility model, or modify it into equivalent embodiments, without departing from the technical principles and scope of this utility model. Therefore, any combination, modification, or substitution made to the disclosed technical features of this utility model based on its technical essence, without departing from the principles or solution of this utility model, should fall within the protection scope of this utility model.

Claims

1. A high-strength, blast-resistant wing fuel tank, comprising a tank body (1), a reinforcing frame, and a sealing layer (3), characterized in that: The box body (1) is a composite structure, which includes, from the outside to the inside, an impact-resistant layer (11), a barrier layer (12) and an antistatic layer (13); the reinforcing frame is located inside the box body (1) and is formed by multiple cross-section I-beams (21) intersecting to form a spatial grid structure. The central thickness of the web (211) of each I-beam (21) is greater than the end thickness, and at least one weight-reducing hole (212) is opened on the web (211); the inner wall of the box body (1) is provided with a boss structure (14) that matches the profile of the flange (213) side surface of the I-beam (21); the sealing layer (3) is embedded in the frame grid and has a stepped sealing groove (31) on the edge, which is interference fit with the flange (213) of the I-beam (21).

2. The high-strength blast-resistant wing fuel tank according to claim 1, characterized in that: The impact-resistant layer (11) is made of carbon fiber reinforced composite material, the barrier layer (12) is made of aluminum alloy foil material, the barrier layer (12) has isolation membranes on both sides, and the antistatic layer (13) is made of conductive polymer coating.

3. A high-strength blast-resistant wing fuel tank according to claim 2, characterized in that: The height H and width D of the boss structure (14) satisfy: 0.2 ≤ H / D≤ 0.5, forming a continuous surface support for the flange (213).

4. A high-strength, blast-resistant wing fuel tank according to claim 3, characterized in that: The thickness of the web (211) of the I-beam (21) gradually changes from the center to the end in an arc-shaped curve, with the thickness at the center being 1.5-2 times that at the end.

5. A high-strength, blast-resistant wing fuel tank according to claim 4, characterized in that: The weight-reducing hole (212) is a dumbbell-shaped through hole, with its long axis parallel to the length direction of the I-beam (21).

6. A high-strength, blast-resistant wing fuel tank according to claim 5, characterized in that: The end of the I-beam (21) is fixed to the boss structure (14) on the inner wall of the box (1) by laser welding, and a fuel-resistant elastic sealant layer is filled on the outside of the welding area.

7. A high-strength, blast-resistant wing fuel tank according to claim 6, characterized in that: The box (1) has a locally thickened structure (15) on the inner wall of the corner area, and the thickened area and the straight area are smoothly transitioned by an arc surface.

8. The high-strength blast-resistant wing fuel tank according to any one of claims 1-7, characterized in that: The contours of the two end faces of the box (1) conform to the curved surfaces of the wing ribs.

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