Sandwich skin structure containing active cooling channel based on additive manufacturing

Abstract

The invention provides an interlayer skin structure containing an active cooling channel based on additive manufacturing. The interlayer skin structure comprises a plurality of interlayer skin assemblies and a plurality of cooling liquid connecting pipes which are arranged in an array mode. Each interlayer skin assembly comprises a grating structure, an upper wall plate, a lower wall plate, two slot structures and two plug lug structures; the upper wall plate is arranged on the upper side of the grid structure, the lower wall plate is arranged on the lower side of the grid structure, and the two slot structures and the two plug lug structures are alternately arranged on the four side faces of the grid structure; each interlayer skin assembly is integrally formed by adopting a fiber reinforced composite material through additive manufacturing and layering design from bottom to top; the slot structure of each interlayer skin assembly is connected with the plug lug structure of the adjacent interlayer skin assembly; one end of each cooling liquid connecting pipe is connected with the cooling liquid inlet of one interlayer skin assembly, and the other end of each cooling liquid connecting pipe is connected with the cooling liquid outlet of the other adjacent interlayer skin assembly, so that the active cooling channels in all the interlayer skin assemblies are communicated with one another.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of additive manufacturing structure design, and particularly relates to a sandwich skin structure with active cooling channels based on additive manufacturing. BACKGROUND

[0002] The fiber-reinforced composite material additive manufacturing technology breaks through the preparation of complex structures that cannot be realized by traditional manufacturing methods in the field of structure design, and has advantages such as rapid preparation, integrated assembly, simplified assembly, and reduced material waste. The fiber-reinforced composite material additive manufacturing technology has the advantages of strength leap, lightweight, and design freedom, and is reshaping the high-end manufacturing industry.

[0003] The sandwich skin structure of the fiber-reinforced composite material additive manufacturing can be applied to the field of aerospace, and the additive manufacturing can reduce the mass of the aircraft skin structure and realize lightweight design of the structure. However, due to the limitation of material types and performance in casting, and the influence of weld strength in welding, the existing production process is difficult to realize the manufacturing of the sandwich skin structure with active cooling channels. SUMMARY

[0004] The present application provides a sandwich skin structure with active cooling channels based on additive manufacturing, which adopts a fiber-reinforced additive manufacturing process for lightweight design and meets the requirements of aircraft skin structure bearing and shape maintaining under complex environments in the field of aerospace.

[0005] According to one aspect of the present application, a sandwich skin structure with active cooling channels based on additive manufacturing is provided, which includes a plurality of sandwich skin components arranged in an array and a plurality of cooling liquid connection pipes.

[0006] Each sandwich skin component includes a grid structure, an upper wall plate, a lower wall plate, two slot structures, and two lug structures. The upper wall plate is arranged on the upper side of the grid structure, the lower wall plate is arranged on the lower side of the grid structure, and the two slot structures and the two lug structures are alternately arranged on the four sides of the grid structure. Each sandwich skin component is integrally formed by additive manufacturing layer design from bottom to top using a fiber-reinforced composite material.

[0007] The grid structure includes a rectangular frame and (N2+1) flow channel support walls disposed within the rectangular frame; both end faces of the (N2+1) flow channel support walls along the length direction of the grid structure are at a predetermined distance from the rectangular frame, and the (N2+1) flow channel support walls are equally spaced along the width direction of the grid structure, thereby realizing that the grid structure, the upper wall plate, and the lower wall plate together form N2 active cooling channels, one channel inlet, and one channel outlet; the lower wall plate is provided with a coolant inlet connected to the channel inlet and a coolant outlet connected to the channel outlet;

[0008] The slot structure of each sandwich skin assembly is connected to the lug structure of the adjacent sandwich skin assembly, thereby realizing the mechanical connection of all sandwich skin assemblies.

[0009] Each coolant connection pipe connects to the coolant inlet of one of the sandwich skin assemblies at one end and to the coolant outlet of another adjacent sandwich skin assembly at the other end, thereby enabling the active cooling channels within all sandwich skin assemblies to be interconnected.

[0010] Preferably, each of the flow channel support walls includes two flow channel walls spaced apart along the length of the grid structure and N1 support walls spaced apart between the two flow channel walls, wherein the flow channel walls and the support walls are perpendicular to each other.

[0011] Preferably, the parameters of the sandwich skin structure satisfy the following constraints:

[0012] N1≥3

[0013] H4 <L4 / 2

[0014] N1·H5 <L1

[0015] L4 = (L2 - L3 * N2) / (N2 + 1)

[0016] In the formula, N1 is the number of support walls in each flow channel support wall, N2 is the number of active cooling flow channels, H4 is the thickness of the flow channel wall, H5 is the thickness of the support wall, L1 is the length of the sandwich skin assembly, L2 is the width of the sandwich skin assembly, L3 is the width of the active cooling flow channel, and L4 is the width of the flow channel support wall.

[0017] Preferably, the fiber layup of the upper and lower wall panels is quasi-isotropic [45, 0, -45, 90, 90, -45, 0, 45]. s [45, -45] s [0, 90] s One or more of these are mixed; the fiber layup method of the grid structure is a continuous fiber layup in the 0° direction.

[0018] Preferably, in the case that the thickness of the upper wall plate and the lower wall plate is less than the preset thickness, each sandwich skin assembly is laid with fiber angles of [45, -45] s , [0, 90] s , [0, 90] s , [0, 90] Preferably, in the case that the thickness of the upper wall plate and the lower wall plate is greater than or equal to the preset thickness, each sandwich skin assembly is laid with quasi-isotropic fiber angles of [45, 0, -45, 90, 90, -45, 0, 45] s .

[0019] Preferably, a plurality of connecting through holes are arranged on each of the slot structures and the lug structures; the connection of each of the slot structures and the lug structures is realized by bolts, so as to realize the connection of two adjacent sandwich skin assemblies.

[0020] According to another aspect of the present application, there is provided an aircraft comprising any of the above-mentioned sandwich skin structures based on additive manufacturing and containing active cooling channels.

[0021] According to the technical scheme of the present application, each sandwich skin assembly comprises a grid structure, an upper wall plate, a lower wall plate, two slot structures and two lug structures; the upper wall plate is arranged on the upper side of the grid structure, the lower wall plate is arranged on the lower side of the grid structure, and the two slot structures and the two lug structures are alternately arranged on the four side surfaces of the grid structure; each sandwich skin assembly is integrally formed by additive manufacturing and layering from bottom to top using fiber reinforced composite materials; the sandwich skin structure based on additive manufacturing of fiber reinforced composite materials can be integrally formed by layering from bottom to top. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings, which are included to provide a further understanding of the embodiments of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is readily apparent to one skilled in the art that the following figures are only some embodiments of the present application, and other figures can be obtained by those skilled in the art without creative efforts on the basis of these figures.

[0023] Figure 1 Fig. 1 shows a front equal side view of a sandwich skin structure based on additive manufacturing and containing active cooling channels according to an embodiment of the present application;

[0024] Figure 2 Fig. 2 shows an assembly view of a sandwich skin structure based on additive manufacturing and containing active cooling channels according to an embodiment of the present application;

[0025] Figure 3 shows Figure 2 a front isometric view of a sandwich skin assembly of a sandwich skin structure;

[0026] Figure 4 shows Figure 2 an exploded view of a sandwich skin assembly of a sandwich skin structure;

[0027] Figure 5 shows Figure 3 a cross-sectional view of a sandwich skin assembly;

[0028] Figure 6 shows Figure 3 a schematic view of a grid structure of a sandwich skin assembly;

[0029] Figure 7 shows Figure 3 a fiber layup pattern of a sandwich skin assembly;

[0030] Figure 8 shows

[0031] Figure 9 shows

[0032] Figure 10 shows

[0033] wherein the above drawings include the following reference signs:

[0034] 11, slot structure, 12, connecting through hole, 13, plug ear structure, 21, cooling liquid inlet, 22, cooling liquid outlet, 31, grid structure, 32, upper wall plate, 33, lower wall plate, 41, cooling liquid connecting pipe. DETAILED DESCRIPTION

[0035] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0036] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0037] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0038] like Figures 1-7 As shown, the present invention provides a sandwich skin structure with active cooling channels based on additive manufacturing, including a plurality of sandwich skin components arranged in an array and a plurality of coolant connecting pipes 41.

[0039] Each sandwich skin assembly includes a grid structure 31, an upper wall panel 32, a lower wall panel 33, two slot structures 11, and two lug structures 13; the upper wall panel 32 is disposed on the upper side of the grid structure 31, the lower wall panel 33 is disposed on the lower side of the grid structure 31, and the two slot structures 11 and the two lug structures 13 are alternately disposed on the four sides of the grid structure 31; each sandwich skin assembly is integrally formed using fiber-reinforced composite material through bottom-up additive manufacturing layup design;

[0040] The grid structure 31 comprises a rectangular frame and (N2+1) flow channel support walls arranged in the rectangular frame; the (N2+1) flow channel support walls are both away from the rectangular frame by a preset distance along the length direction of the grid structure 31, and the (N2+1) flow channel support walls are arranged at equal intervals along the width direction of the grid structure 31, so that the grid structure 31, the upper wall plate 32 and the lower wall plate 33 together form N2 active cooling channels, one channel inlet and one channel outlet; the lower wall plate 33 is provided with a cooling liquid inlet 21 communicated with the channel inlet and a cooling liquid outlet 22 communicated with the channel outlet;

[0041] The slot structure 11 of each sandwich skin assembly is connected with the lug structure 13 of an adjacent sandwich skin assembly, so as to realize mechanical connection of all the sandwich skin assemblies;

[0042] One end of each cooling liquid connecting pipe 41 is connected with the cooling liquid inlet 21 of one sandwich skin assembly, and the other end is connected with the cooling liquid outlet 22 of another adjacent sandwich skin assembly, so that the active cooling channels in all the sandwich skin assemblies are communicated with each other.

[0043] The sandwich skin assembly is integrally formed by a fiber-reinforced additive manufacturing technology, and the size (length, width) of the single-piece sandwich skin assembly is 200-3000 mm.

[0044] The upper wall plate 32 and the lower wall plate 33 in the sandwich skin assembly are substantially large plane structures, which can be adjusted according to the aircraft shape, and the fiber layering mode is quasi-isotropic [45, 0, -45, 90, 90, -45, 0, 45] s , [45, -45] s , [0, 90] s , one or more of which are mixed, to enhance the load-bearing performance of the sandwich skin structure.

[0045] Specifically, when the thickness of the upper wall plate 32 and the lower wall plate 33 is less than a preset thickness, each sandwich skin assembly adopts the fiber angles of [45, -45] s , [0, 90] s ; when the thickness of the upper wall plate 32 and the lower wall plate 33 is greater than or equal to the preset thickness, each sandwich skin assembly adopts the quasi-isotropic fiber angles of [45, 0, -45, 90, 90, -45, 0, 45] s .

[0046] The fiber layering mode of the grid structure 31 in the sandwich skin assembly is continuous layering of 0° direction fibers, and the rib plate structure supports the ability to support aerodynamic load and the ability to support cooling liquid pressure. Among them, continuous layering of 0° direction long fibers can be used. Each of the flow channel support walls includes two flow channel walls spaced apart along the length direction of the grid structure 31 and N1 support walls spaced apart between the two flow channel walls, the flow channel walls and the support walls are perpendicular to each other, while increasing the bearing capacity, having the advantage of lightweight.

[0047] Each of the slot structures 11 and the lug structures 13 in the sandwich skin assembly is provided with a plurality of connecting through holes 12; the connection of each of the slot structures 11 and the lug structures 13 is realized by bolts, thereby realizing the connection of two adjacent sandwich skin assemblies. That is, the connection between the sandwich skin assemblies, the connection between the sandwich skin structure and the aircraft beam rib / truss structure is realized by using bolts, and the connection between the cooling liquid inlet and outlet of the sandwich skin is realized by the cooling liquid inlet and outlet connection pipe 41.

[0048] Specifically, the hole diameter of the connecting through hole 12 is 5-50mm, the spacing between the through holes 12 is 10-300mm, the hole is punched after the sandwich skin is integrally manufactured, the outer diameter of the cooling liquid inlet and outlet (21, 22) is 10-100mm, the wall thickness is 1-20mm, and the length of the cooling liquid inlet and outlet (21, 22) is 10-500mm. The sandwich skin structure is selected to be resin-based-carbon fiber structure, realizing lightweight design of the sandwich skin, the minimum layering thickness of the 3D printer is set to 0.2mm-0.5mm according to the machine nozzle setting, the fiber direction at the corner is avoided to accumulate resin, and the acceleration is large, and the minimum corner radius is 0.2mm. When the upper and lower wall plates of the sandwich skin structure are relatively thin, the thickness is less than 2mm, the [45,-45]s and [0,90]s fiber angles are used for layering, and when the upper and lower wall plates of the sandwich skin structure are relatively thick, the thickness is greater than 2mm, the quasi-isotropic [45,0,-45,90,90,-45,0,45]s fiber angle is used for layering.

[0049] The use conditions of the sandwich skin structure are that the external aerodynamic load is not greater than 40kpa, the external environment temperature is not higher than 1500℃, and the aircraft operation time is 1000-5000s.

[0050] In order to realize the lightweight of the sandwich skin structure and the bearing, shape maintaining and other effects of the skin structure of the aircraft in the complex environment of the aerospace field, each parameter of the sandwich skin structure satisfies the following constraint conditions:

[0051] N1≥3

[0052] H4<L4 / 2

[0053] N1·H5<L1

[0054] L4 = (L2 - L3*N2) / (N2 + 1)

[0055] The structural integrity can be ensured under the above constraints, and exceeding the above constraints will cause the sandwich skin structure to deform. L4 is constrained by L2, L3, and N2 due to geometric size relationship, the number of support plates N1 must be at least 3 to stably bear the aerodynamic load, and H4 is constrained by L4, and cannot exceed half of L4 to ensure structural integrity. The parameters L3, L4, N1, N2, H1, H2, H3, H4, H5, X0, X1, and X2 of the sandwich skin structure and the thermal protection system are optimized to obtain a lightweight structure of the skin thermal protection system.

[0056] L1 is the length of the sandwich skin assembly, L2 is the width of the sandwich skin assembly, L3 is the width of the actively cooled flow channel, L4 is the width of the flow channel support wall, N1 is the number of support walls in each flow channel support wall, N2 is the number of actively cooled flow channels, H1 is the thickness of the upper and lower wall plates, H2 is the thickness of the thermal protection layer, H3 is the height of the actively cooled flow channel, H4 is the thickness of the flow channel wall, H5 is the thickness of the support wall, X0 is the fiber layer angle of the upper and lower wall plates, X1 is the fiber layer angle of the flow channel wall, and X2 is the fiber layer angle of the support wall.

[0057] To further realize lightweight design of the structure, the sandwich skin structure can be optimized in structural parameters by the multi-island genetic algorithm. In the design of the sandwich skin structure, the length L1 and the width L2 of the sandwich skin assembly, the outer diameter R0 and the wall thickness L R of the cooling liquid inlet and outlet, the number N3 and the radius R1 of the sandwich skin connecting through holes are initial values, and the thickness H1 of the upper and lower wall plates of the sandwich skin, the thickness H2 of the thermal protection layer, the number N1 of the support plates of the grid structure, the number N2 of the actively cooled channels in the grid structure, the width L3 of the actively cooled channel, the width L4 of the flow channel support wall, the longitudinal thickness H4, and the transverse thickness H5 are optimized in parameters.

[0058] In the embodiment, the sandwich skin structure and the outer thermal protection system are connected by bonding, as shown in FIG. 8, and then the sandwich skin structure and the thermal protection system are optimized in structural parameters by the multi-island genetic algorithm as a whole, as shown in FIG. 9, and the specific process includes: Figure 8 Figure 9

[0059] Step one, heat transfer analysis is performed according to the material physical properties of the sandwich skin structure and the thermal protection system and the ambient temperature to obtain the thermal response temperature field of the lower surface of the sandwich skin structure;

[0060] Step two, the highest temperature field time is obtained from the thermal response temperature field of the lower surface of the sandwich skin structure, and the thermal stress of the sandwich skin structure and the thermal protection system is obtained.​​

[0061] Step 3: Extract the maximum thermal stress value on the lower surface of the sandwich skin structure from the thermal stress of the sandwich skin structure and the thermal protection system;

[0062] Step 4: Extract the highest temperature value of the lower surface of the sandwich skin structure from the thermal response temperature field of the lower surface of the sandwich skin structure;

[0063] Step 5: Obtain the mass of the sandwich skin structure and the thermal protection system, and use the maximum thermal stress value on the lower surface of the sandwich skin structure, the highest temperature value on the lower surface of the sandwich skin structure, and the mass of the sandwich skin structure and the thermal protection system as constraints.

[0064] Step 6: Under constraints, use a multi-island genetic algorithm to optimize the structural parameters of the sandwich skin structure and the thermal protection system to obtain a lightweight skin thermal protection system structure.

[0065] The thermal response temperature field of the lower surface of the sandwich skin structure is obtained by the following formula:

[0066]

[0067] In the formula, ρ is the material density of the sandwich skin structure or thermal protection system, and C p It is the specific heat capacity of the material in a sandwich skin structure or thermal protection system, kJ / m³. x k y k z It is the heat transfer coefficient of the material in the x, y, and z directions of a sandwich skin structure or thermal protection system. This is the internal heat source term, representing the heat generated inside the sandwich skin structure or thermal protection system, measured in W / m². 3 T is the ambient temperature, and t is time. For example... Figure 3 As shown, the x-direction is the length direction of the sandwich skin assembly, the y-direction is the width direction of the sandwich skin assembly, and the z-direction is the height direction of the sandwich skin assembly.

[0068] The thermal strain of the sandwich skin structure and the anisotropic structure of the thermal protection system can be obtained by the following formula:

[0069]

[0070] In the formula, It is the positive thermal strain tensor in the x, y, and z directions. These are the shear thermal strain tensors in the xy, yz, and zx planes, respectively, T. ref It is the initial temperature of the sandwich skin structure and the overall thermal protection system, α. xx α yy α zz Let α represent the coefficients of linear expansion in the x, y, and z directions, respectively.xy , α yz , α zx respectively represent the shear thermal expansion coefficients in the xy, yz, zx planes.

[0071] The total strain of the sandwich skin structure and the thermal protection system is obtained by the following formula:

[0072] ε total = ε el + ε pl + ε th

[0073]

[0074] In the formula, ε total is the total mechanical strain, ε el is the elastic strain, ε pl is the plastic deformation, and ε th is the thermal strain.

[0075] According to the total strain of the sandwich skin structure and the thermal protection system, the system thermal stress is obtained by the anisotropic elastic constitutive equation:

[0076] σ = D : ( ε total - ΔT · α )

[0077] ΔT = T - T ref

[0078]

[0079] In the formula, σ is the thermal stress of the sandwich skin structure and the thermal protection system, D is the anisotropic elastic stiffness matrix, ":" is the tensor double dot product, and α is the expansion coefficient.

[0080] Figure 10 The optimization result diagram of the sandwich skin structure and the thermal protection system is shown. Figure 10 It can be known that the sandwich skin structure of the present application can realize lightweight design and meet the requirements of the skin structure of the aircraft in the aerospace field in complex environments, such as bearing and shape maintaining.

[0081] The present application also provides an aircraft, which comprises the above-mentioned sandwich skin structure based on additive manufacturing and containing active cooling channels.

[0082] In summary, the present application provides a kind of sandwich skin structure based on active cooling channel of additive manufacturing, each sandwich skin component includes grid structure, upper wallboard, lower wallboard, two slot structures, two ear structures;The upper wallboard is arranged on the upper side of the grid structure, the lower wallboard is arranged on the lower side of the grid structure, two slot structures and two ear structures are alternately arranged on the four sides of the grid structure;Each sandwich skin component is integrally formed by using fiber reinforced composite material through additive manufacturing layering from bottom to top;It can be realized that the skin structure is loaded under the complex environment of aircraft in the field of aerospace, and the shape is maintained while realizing lightweight design.The fiber reinforced composite material additive manufacturing sandwich skin structure can be integrally formed by layering from bottom to top.

[0083] For the convenience of description, spatial relative terms such as "over", "above", "upper surface", "upper", etc. can be used herein to describe the spatial positional relationship of one device or feature with other devices or features as shown in the drawings. It should be understood that the spatial relative terms are intended to include different orientations in use or operation in addition to the orientation of the device described in the drawings. For example, if the device in the drawing is inverted, the device described as "above" or "over" other devices or structures will be positioned "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below" orientations. The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein are interpreted accordingly.

[0084] In addition, it should be noted that the use of "first", "second" and the like words to define parts is only for the convenience of distinguishing the corresponding parts, and the above words have no special meaning unless otherwise stated, therefore cannot be understood as limiting the protection scope of the present application.

[0085] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An additive manufacturing based sandwich skin structure containing active cooling channels, characterized in that, The arrayed sandwich skin structure comprises a plurality of sandwich skin assemblies and a plurality of cooling liquid connecting pipes. Each sandwich skin assembly comprises a grid structure, an upper wall plate, a lower wall plate, two slot structures, and two lug structures. The upper wall plate is arranged on the upper side of the grid structure, the lower wall plate is arranged on the lower side of the grid structure, and the two slot structures and the two lug structures are alternately arranged on the four sides of the grid structure. Each sandwich skin assembly is integrally formed by using fiber-reinforced composite material through bottom-up additive manufacturing layer design. The grid structure comprises a rectangular frame and (N2+1) flow channel support walls arranged in the rectangular frame. The (N2+1) flow channel support walls have a predetermined distance from the rectangular frame along the two end faces of the length direction of the grid structure, and the (N2+1) flow channel support walls are equally spaced along the width direction of the grid structure, so as to realize that the grid structure, the upper wall plate, and the lower wall plate jointly enclose N2 active cooling channels, a channel inlet, and a channel outlet. The lower wall plate is provided with a cooling liquid inlet communicating with the channel inlet and a cooling liquid outlet communicating with the channel outlet. The slot structure of each sandwich skin assembly is connected with the lug structure of the adjacent sandwich skin assembly, so as to realize the mechanical connection of all sandwich skin assemblies. One end of each cooling liquid connecting pipe is connected with the cooling liquid inlet of one of the sandwich skin assemblies, and the other end is connected with the cooling liquid outlet of the other adjacent sandwich skin assembly, so as to realize that the active cooling channels in all sandwich skin assemblies are connected with each other.

2. The sandwich skin structure of claim 1, wherein Each flow channel support wall comprises two flow channel walls spaced apart along the length direction of the grid structure and N1 support walls spaced apart between the two flow channel walls, and the flow channel walls and the support walls are perpendicular to each other.

3. Sandwich skin structure according to claim 1 or 2, characterized in that The parameters of the sandwich skin structure satisfy the following constraint conditions: N1≥3 H4 < L4 / 2 N1·H5 < L1 L4 = (L2-L3*N2) / (N2+1) In the formula, N1 is the number of support walls in each flow channel support wall, N2 is the number of active cooling channels, H4 is the thickness of the flow channel wall, H5 is the thickness of the support wall, L1 is the length of the sandwich skin assembly, L2 is the width of the sandwich skin assembly, L3 is the width of the active cooling channel, and L4 is the width of the flow channel support wall.

4. Sandwich skin structure according to any of claims 1-3, characterized in that The fiber layup of the upper wall panel, the lower wall panel is one or more of the following: [45, 0, -45, 90, 90, -45, 0, 45] s , [45, -45] s , [0, 90] s in any combination; the fiber layup of the grid structure is a continuous layup of 0° fibers.

5. The sandwich skin structure of claim 4, wherein In the case that the thickness of the upper wall plate and the lower wall plate is less than a preset thickness, each sandwich skin assembly adopts [45, -45] s , [0, 90] s fiber angle for layering; in the case that the thickness of the upper wall plate and the lower wall plate is greater than or equal to the preset thickness, each sandwich skin assembly adopts quasi-isotropic [45, 0, -45, 90, 90, -45, 0, 45] s fiber angle for layering.

6. The sandwich skin structure of claim 1, wherein Each slot structure and lug structure is provided with a plurality of connecting through holes, and the connection of each slot structure and lug structure is realized by bolts, so as to realize the connection of the adjacent two sandwich skin assemblies.

7. An aircraft, characterized in that The aircraft comprises the additive manufacturing-based sandwich skin structure with active cooling channels according to any one of claims 1-6.

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