Laminated structure multi-partition electric heating composite material skin and preparation method thereof

Abstract

The invention relates to a laminated structure multi-partition electric heating composite material skin and a preparation method thereof. The preparation method of the laminated structure multi-partition electric heating composite material skin comprises the steps that a layer of resin film is laid on the surface of a heating assembly, the resin film adopts a resin system the same as that of the skin, vacuum prepressing is conducted for 10-60 min at the temperature of 60-80 DEG C, and a heating film is obtained; the heating films of all the partitions are laid and pre-compacted on different side faces of a layer of standard prepreg, and an integrated multi-partition prefabricated heating layer with the determined position relation is formed; wave-transparent bearing skin prepreg, the prefabricated heating layer and outer-layer wave-transparent skin prepreg are laid on a mold in sequence, co-curing is conducted through a vacuum bag-autoclave system, and the overall skin structure is formed. The technical problems that in the prior art, three-dimensional projection positioning is not accurate, the relative positions of heating partitions are not accurate due to the fact that accumulated errors of layer-by-layer paving are large, gaps or overlapping exist in heating covering, and molded surfaces protrude due to electrode overlapping can be solved.

Description

Technical Field

[0001] This application relates to the field of functional composite material manufacturing technology, and in particular to a laminated multi-zone electrically heated composite material skin and its preparation method. Background Technology

[0002] In modern aerospace, the use of laminated electrothermal composite materials for de-icing has become a mainstream technology. To improve heating efficiency and reduce energy consumption, the heating area is often divided into multiple independently temperature-controlled zones. These zones need to be distributed adjacently to ensure that the entire de-icing area can work effectively. At the same time, to ensure the insulation of adjacent electrodes, they may be distributed at different layup depths in the skin structure to meet the insulation requirements of the relevant areas.

[0003] However, accurately determining the relative positions of these heating zones located in different plies during the manufacturing process and ensuring their reliability is a huge challenge. 1. Difficulty in 3D positioning and uneven heating coverage: When the skin has complex curved surfaces (such as the deep V-shaped structure of the wing leading edge), traditional laser projectors struggle to accurately project the outlines of all zones simultaneously on the 3D curved surface, easily causing projection deviations. This can lead to excessive gaps or overlaps between heating zones, resulting in heating blind spots or localized overheating, making it impossible to achieve full-range, uniform, and efficient heating coverage.

[0004] 2. Risks of Cumulative Errors, Deformation, and Surface Protrusion: If layer-by-layer independent projection positioning is used, the inherent flexibility and variability of the prepreg and heating fabrics can lead to uncontrollable deformation and misalignment during installation and pre-compaction, resulting in cumulative errors in the relative positions of the heating zones between layers. More seriously, when electrodes in different layers overlap or are excessively close in the thickness direction, localized rigid hard spots and material accumulation can form, causing unacceptable protrusions on the skin surface after curing, disrupting the aerodynamic shape, and causing stress concentration under load.

[0005] 3. Insulation reliability risk: Precise laying of insulating material is required between multiple electrodes in multiple zones to prevent short circuits. Inaccurate positioning will lead to deviations in the position of the insulating material, either resulting in insufficient coverage and ineffective insulation, or introducing too much redundant insulating material, which will impair the interlayer mechanical properties.

[0006] Existing technologies lack an integrated solution that can simultaneously guarantee high positioning accuracy, seamless heating across the entire range, excellent interlayer bonding, and reliable insulation. Summary of the Invention

[0007] This application provides a laminated multi-zone electrically heated composite material skin and its preparation method to solve at least one of the problems in the above-mentioned background art.

[0008] In a first aspect, this application provides a method for preparing a laminated multi-zone electrically heated composite material skin, comprising: A resin film is laid on the surface of the heating component. The resin film uses the same resin system as the skin. The heating film is pre-pressed under vacuum at 60-80℃ for 10-60 minutes. The heating films of all zones are laid and pre-pressed onto different sides of a base prepreg to form an integrated, multi-zone prefabricated heating layer with a defined positional relationship. The wave-transparent bearing skin prepreg, the pre-heated layer, and the outer wave-transparent skin prepreg are sequentially laid on the mold and co-cured using a vacuum bag-autoclave system to form an integral skin structure.

[0009] Furthermore, before applying a resin film to the surface of the heating component, the process further includes: According to the design, conductive fabric for each section is precisely cut using laser and electrodes are installed to obtain the heating component.

[0010] Furthermore, the step of laying and pre-pressing the heating film of all zones onto different sides of a reference prepreg to form an integrated, positionally defined multi-zone prefabricated heating layer includes: On a flat reference layer, the heating films of all zones are pre-assembled into a whole multi-zone prefabricated heating layer by alternating flipping operations.

[0011] Furthermore, the multi-zone prefabricated heating layer, which pre-assembles all the heating films of a single zone into a whole through an alternating flipping operation on a reference layer in a plane, includes: Take a layer of prepreg as a reference layer and lay it flat on the flat tooling plate. Precisely position and attach the heating film with electrodes in the first section on the front side of the prepreg. Flip the entire base layer together with the first zone heating film on it so that the reverse side is facing up, and position and lay the insulation layer and the two zone heating films on the reverse side. Flip the base layer back to face up, and continue to apply the insulation layer and two partition heating films on the front side, with their positions complementary to the reverse side, to ensure full coverage. Repeat the above flipping and laying steps until all the designed zone heating films are integrated into this single layer of base prepreg to form a whole multi-zone prefabricated heating layer.

[0012] Furthermore, after taking a layer of prepreg as a reference layer and laying it flat on the planar tooling plate, and precisely positioning and attaching the heating film with electrodes in the first section on the front side of the prepreg, the process further includes: Vacuum bag pre-compacts the front side of the first zone heating film after it has been laid, so that it is initially fixed to the prepreg of the base layer and the air is removed.

[0013] Furthermore, the positioning and application of the insulating layer and the two partitioned heating films on the reverse side includes: In the area corresponding to the projection of the front electrode on the back, an insulating layer with adhesive film is laid. The width of the insulating layer is designed to be the sum of the widths of the two electrodes plus 6mm. When laying it, ensure that it is 3mm wider on each side of the electrode. Using the electrodes and heating film already fixed on the front as a reference, locate and lay the heating film and electrodes of the two adjacent sections on the opposite side, with the reverse electrode resting against the inside of the front electrode.

[0014] Furthermore, after positioning and applying the insulating layer and the two partitioned heating films on the reverse side, the process further includes: Vacuum bag pre-compacts the back side after the tiling is completed to fix the insulation layer and the two partition heating films on the back side.

[0015] Secondly, this application provides a laminated multi-zone electrically heated composite material skin, which is obtained by the preparation method of the laminated multi-zone electrically heated composite material skin as described above.

[0016] The above-mentioned technical solution of this application has the following advantages: The laminated multi-zone electrically heated composite material skin and its preparation method provided in this application involve laying a resin film on the surface of the heating component. The resin film uses the same resin system as the skin and is vacuum pre-pressed at 60-80℃ for 10-60 minutes to obtain a heating film. The heating films of all zones are laid and pre-pressed onto different sides of a reference prepreg to form an integrated, multi-zone prefabricated heating layer with a defined positional relationship. The wave-transparent bearing skin prepreg, the prefabricated heating layer, and the outer wave-transparent skin prepreg are sequentially laid on a mold and co-cured using a vacuum bag-autoclave system to form an integral skin structure. This method can overcome the technical problems in the prior art, such as inaccurate three-dimensional projection positioning, large cumulative error in layer-by-layer laying leading to inaccurate relative positions of heating zones, gaps or overlaps in heating coverage, and surface protrusions caused by electrode overlap. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A schematic diagram illustrating the application of this invention, showing the application of a first-zone heating film being laid on the front side of a reference layer and pre-compacted. Figure 2 A schematic diagram showing the application of an embodiment of this application, in which insulating material and heating films for the second and third zones are laid on the reverse side based on the projection of the front electrode; Figure 3 A schematic diagram illustrating the application embodiment of the heating film for sections 4 and 5 after the film is flipped back to the front. Figure 4 This is a schematic diagram of the structure of the multi-zone prefabricated heating layer provided in the embodiments of this application. Detailed Implementation

[0019] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0021] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0022] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0023] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as µg, mg, g, or kg.

[0024] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0025] This application belongs to the field of functional composite material manufacturing technology, specifically relating to a method for achieving precise layup positioning of multi-zone electrically heated materials in laminated structures such as aircraft skin, and for the integrated preparation of structures with efficient anti-icing and stealth functions.

[0026] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0027] This application aims to overcome technical challenges in the prior art, such as inaccurate three-dimensional projection positioning, large cumulative errors in layer-by-layer bonding leading to inaccurate relative positions of heating zones, gaps or overlaps in heating coverage, and surface protrusions caused by electrode overlap. Simultaneously, it provides an integrated fabrication method that can achieve both efficient zoned heating and excellent stealth performance. To achieve the above objectives, this application provides a method for fabricating a multi-zoned electrically heated composite material skin with a laminated structure. The core of this method lies in a high-precision "alternating flipping positioning method" and its application in the fabrication of multifunctional structures.

[0028] This application provides a method for preparing a laminated multi-zone electrically heated composite material skin, comprising the following two parts: Part 1: Core Positioning and Preparation Method – “Alternating Flipping Positioning Method” The core of the method lies in the fact that, on a plane reference layer, by alternating flipping operations, all the heating films in the partitions are pre-assembled into a whole "prefabricated heating layer", thereby transforming the complex three-dimensional spatial positioning problem into a precise two-dimensional planar positioning problem.

[0029] The method includes the following steps: 1. Preparation of the reference layer and initial positioning of surface A: such as Figure 1 As shown, a layer of prepreg is taken as the base layer and laid flat on the flat tooling plate. Using a laser projector or high-precision positioning film, the heating film with electrodes in the first section is accurately positioned and laid on the front side (side A) of the prepreg.

[0030] 2. Initial pre-compaction of surface A: Vacuum bag pre-compacts surface A, where the first zone heating film has been laid, to initially fix it to the prepreg material of the reference layer and remove air.

[0031] 3. Flip and Precisely Install Side B: Flip the entire base layer along with the first section heating film on it, so that the reverse side (Side B) is facing upwards. For example... Figure 2 As shown, perform the following operations on side B: Precise application of the insulation layer: The precise projection area of ​​the electrode on side B corresponding to side A can be directly determined visually or by touch. An insulation layer with adhesive film (preferably a polyimide PI film with a thickness of 0.05-0.1 mm) is then applied. The width of the insulation layer is designed to be the sum of the widths of both electrodes plus 6 mm. During application, ensure that there is a 3 mm extra width on each side of the electrode to achieve reliable coverage and avoid excess material. This ensures the accuracy and consistency of the insulation.

[0032] Positioning and application of the heating film on side B: Using the electrodes and heating film already fixed on side A as a reference, position and apply the heating film and electrodes of the two adjacent sections on the adjacent sides of side B. The electrodes on side B should be placed inside the electrodes on side A. This design ensures seamless connection between the heating areas on sides A and B, achieving full coverage of the heating function, while strictly avoiding overlapping projections of different electrode layers in the thickness direction, fundamentally eliminating surface protrusion defects caused by electrode stacking.

[0033] 4. Pre-compacting of side B: Vacuum bag pre-compacting is applied to the completed side B to fix the side B components.

[0034] 5. Iterative tiling and final integration: such as Figure 3 As shown, the reference layer is flipped back to face A, and the insulation layer and the fourth and fifth zone heating films are continued to be laid on face A. Their positions are complementary to the components on face B to ensure full coverage.

[0035] Repeat the above steps of flipping, laying, and pre-compacting until all designed zoned heating films are precisely integrated onto this single-layer reference prepreg, such as... Figure 4 As shown, this forms a complete prefabricated heating layer with highly precise relative positions of each section.

[0036] Part Two: Integrated Fabrication of Multifunctional Laminated Skin Using the above positioning method, a multi-zone heated skin can be prepared. The specific steps are as follows: 1. Prefabricated heating layer: a. Preparation of heating components: According to the design, the conductive fabric of each section is precisely cut by laser and the electrodes are installed.

[0037] b. Preparation of heating film: A layer of resin film is laid on the surface of the heating component. The resin can be the same resin system as the skin. Vacuum pre-pressing is carried out at 60-80℃ for 10-60 minutes.

[0038] c. Alternating flipping positioning and integration: Using the above-mentioned "alternating flipping positioning method", the heating film of all zones is accurately laid and pre-pressed on different sides of a reference prepreg to form an integrated, multi-zone prefabricated heating layer with a defined positional relationship.

[0039] 2. Co-curing molding: a. Layering design: The wave-transparent bearing skin prepreg, the pre-fabricated heating layer, and the outer wave-transparent skin prepreg are sequentially laid on the mold.

[0040] b. Curing: Co-curing is carried out using a vacuum bag-autoclave system to form a dense integral skin structure.

[0041] The following is a description through specific embodiments.

[0042] Example This embodiment describes the preparation of a five-zone heated skin based on the alternating flipping method, including the following steps: 1. Design: A certain wing skin requires a total of 5 heating zones, which were originally distributed in 2 different plies.

[0043] 2. Preparation of the prefabricated heating layer: a. Take a layer of quartz fabric reinforced cyanate ester QW120 / 5528A as the reference layer, with side A facing up. Position it using laser projection, lay the heating film of section 1, and pre-compact it by vacuuming.

[0044] b. Flip the film so that side B is facing up. Based on the projection of the electrode on side A onto side B, precisely attach a polyimide insulating film with a width matching the design (total electrode width + 6mm). Then, using the electrode on side A as a reference, position and attach the heating film and electrodes for sections 2 and 3 in adjacent areas, ensuring that the heating area is covered without gaps and that the electrode projections do not overlap. Vacuum pre-compact the film.

[0045] c. Flip the container back to face A. Position and apply the heating film for sections 3 and 4, filling in the remaining area. Vacuum and pre-compact the material again. At this point, all five sections are precisely integrated onto a single layer of prepreg, forming a prefabricated heating layer.

[0046] 3. Integral molding: Lay the lower skin prepreg in the conventional layering sequence, then lay the above-mentioned pre-heated layer as a whole in the designed position, vacuum pre-compact it, and continue to lay the upper skin prepreg.

[0047] 4. Curing: Curing is performed using a standard autoclave process.

[0048] 5. Results: The relative positional error of all zones is less than 1mm, and the heating area is continuous and gapless. Independent temperature control of each zone is normal, with no crosstalk. The skin surface is smooth and without protrusions, and the surface accuracy fully meets aerodynamic requirements. Interlaminar shear strength tests show excellent structural integrity.

[0049] This application also provides a laminated multi-zone electrothermal composite material skin, which is obtained by the preparation method of the laminated multi-zone electrothermal composite material skin described above.

[0050] The laminated multi-zone electrically heated composite material skin and its preparation method provided in this application have the following significant advantages: 1. **Zoned Positioning Accuracy and Full Coverage:** Utilizing an "alternating flipping positioning method," multiple zones are integrated onto different sides of a single reference layer, ensuring extremely high relative positional accuracy between all heating zones (error controllable within 0.5mm). This method avoids three-dimensional cumulative errors through planar positioning, guaranteeing seamless connection of the heating area and achieving truly full-range, gapless, and non-overlapping uniform heating coverage, completely eliminating the risk of overheating in heating blind spots and transition zones.

[0051] 2. Elimination of surface protrusions: By pre-planning and staggering the positions of the electrodes on surfaces A and B on the same reference layer, the overlapping projections of electrodes in different layers in the thickness direction are fundamentally avoided, thereby completely eliminating the surface protrusions of the skin caused by electrode stacking after curing, ensuring the smoothness and integrity of the aerodynamic shape.

[0052] 3. Insulation Reliability and Structural Integrity: Precise insulation is achieved by using the accurate projection of the electrodes after flipping the electrode. The optimized insulation layer dimensions ensure safe spacing while minimizing excess material, avoiding interlayer stress concentration and performance degradation caused by improper insulation material installation, thus guaranteeing structural integrity.

[0053] 4. High-quality interfacial bonding: The "pre-heated layer" is cured as a whole with the main skin structure. Each component has been tightly bonded to the base layer in the pre-compacting stage, which makes the interlayer bonding of the final product far superior to the traditional loose layer-by-layer laying process.

[0054] 5. Strong process robustness and low cost: This method reduces the dependence on complex three-dimensional laser projection equipment, and high-precision prefabrication can be completed on planar tooling. The process is stable and has good repeatability, which greatly reduces the manufacturing difficulty, scrap rate and overall cost.

[0055] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. This application is not limited to the specific methods described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0056] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for preparing a multi-zoned electrically heated composite material skin with a laminated structure, characterized in that, include: A resin film is laid on the surface of the heating component. The resin film uses the same resin system as the skin. The heating film is pre-pressed under vacuum at 60-80℃ for 10-60 minutes. The heating films of all zones are laid and pre-pressed onto different sides of a base prepreg to form an integrated, multi-zone prefabricated heating layer with a defined positional relationship. The wave-transparent bearing skin prepreg, the pre-heated layer, and the outer wave-transparent skin prepreg are sequentially laid on the mold and co-cured using a vacuum bag-autoclave system to form an integral skin structure.

2. The method for preparing the multi-zone electrically heated composite material skin with a laminated structure as described in claim 1, characterized in that, Before applying a resin film to the surface of the heating component, the process further includes: According to the design, conductive fabric for each section is precisely cut using laser and electrodes are installed to obtain the heating component.

3. The method for preparing the laminated multi-zone electrically heated composite material skin as described in claim 1, characterized in that, The process of laying and pre-pressing the heating film of all zones onto different sides of a base prepreg to form an integrated, positionally defined multi-zone prefabricated heating layer includes: On a flat reference layer, the heating films of all zones are pre-assembled into a whole multi-zone prefabricated heating layer by alternating flipping operations.

4. The method for preparing the laminated multi-zone electrically heated composite material skin as described in claim 3, characterized in that, The multi-zone prefabricated heating layer, which integrates all the heating films of a single zone into a whole through an alternating flipping operation on a reference layer in a plane, includes: Take a layer of prepreg as a reference layer and lay it flat on the flat tooling plate. Precisely position and attach the heating film with electrodes in the first section on the front side of the prepreg. Flip the entire base layer together with the first zone heating film on it so that the reverse side is facing up, and position and lay the insulation layer and the two zone heating films on the reverse side. Flip the base layer back to face up, and continue to apply the insulation layer and two partition heating films on the front side, with their positions complementary to the reverse side, to ensure full coverage. Repeat the above flipping and laying steps until all the designed zone heating films are integrated into this single layer of base prepreg to form a whole multi-zone prefabricated heating layer.

5. The method for preparing the laminated multi-zone electrically heated composite material skin as described in claim 4, characterized in that, The process of taking a layer of prepreg as a reference layer and laying it flat on a planar tooling plate, and then precisely positioning and attaching the heating film with electrodes in the first section on the front side of the prepreg, further includes: Vacuum bag pre-compacts the front side of the first zone heating film after it has been laid, so that it is initially fixed to the prepreg of the base layer and the air is removed.

6. The method for preparing the laminated multi-zone electrically heated composite material skin as described in claim 4, characterized in that, The positioning and application of the insulating layer and the two partitioned heating films on the reverse side includes: In the area corresponding to the projection of the front electrode on the back, an insulating layer with adhesive film is laid. The width of the insulating layer is designed to be the sum of the widths of the two electrodes plus 6mm. When laying it, ensure that it is 3mm wider on each side of the electrode. Using the electrodes and heating film already fixed on the front as a reference, locate and lay the heating film and electrodes of the two adjacent sections on the opposite side, with the reverse electrode resting against the inside of the front electrode.

7. The method for preparing the laminated multi-zone electrically heated composite material skin as described in claim 4, characterized in that, After positioning and applying the insulating layer and the two partitioned heating films on the reverse side, the process also includes: Vacuum bag pre-compacts the back side after the tiling is completed to fix the insulation layer and the two partition heating films on the back side.

8. A laminated multi-zone electrically heated composite material skin, characterized in that, The skin is obtained by the method for preparing a multi-zoned electrothermal composite material skin with a laminated structure as described in any one of claims 1 to 7.

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