A method of repairing an electrically heated composite material
By setting a conductive overlap part to be directly electrically connected to the heating resistance layer during the repair process of the electrically heated composite material, and detecting the temperature uniformity in the sealed cavity, the problems of insufficient electrical continuity and electrothermal stability in the prior art are solved, and efficient and reliable repair results are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YUANJIAN WIND POWER JIANGYINENVISION ENERGY CO LTD
- Filing Date
- 2026-02-28
- Publication Date
- 2026-06-05
AI Technical Summary
Existing repair methods for electrically heated composite materials cannot guarantee the electrical continuity between the repaired area and the original heating circuit, and cannot effectively verify the electrical performance before sealing and curing. This results in high contact resistance or open circuit risks at the overlapping interface, and cannot ensure the electrothermal stability under long-term service.
Conductive overlaps are set at the edge of the repair material and directly electrically connected to the heating resistance layer of the undamaged zone. A sealed cavity is formed around the repair area. After vacuuming, resin is poured in. The temperature uniformity is detected by energizing the test circuit to ensure that the electrothermal performance of the repair material meets the target requirements before curing.
It significantly improves the repair effect of electrically heated composite materials, avoids local overheating or heating failure caused by poor overlap or material defects, and ensures reliable electrical integration and long-term service reliability between the repaired area and the original heating circuit.
Smart Images
Figure CN122160948A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of electric heating anti-icing technology, and in particular to a repair method for an electric heating composite material. Background Technology
[0002] Electrically heated composite materials are advanced laminated composite materials that integrate conductive heating elements. Their working principle is based on the Joule heating effect: when energized, the conductive layer generates heat due to resistance, thereby achieving active heating of the material's surface or interior. Due to this characteristic, these composite materials are widely used in aerospace, wind power, and rail transportation, and are particularly suitable for critical components requiring anti-icing, de-icing, insulation, or precise temperature control.
[0003] However, in actual service, electrically heated composite materials may be subjected to complex loads such as impacts from foreign objects, mechanical fatigue, and lightning strikes, leading to localized structural damage. Such damage not only weakens the mechanical properties of the material but may also cause breakage, short circuits, or poor contact in the conductive heating layer, thereby causing localized failure of the heating function—manifested as the formation of "cold zones," or localized overheating due to current concentration, and even posing safety hazards. Summary of the Invention
[0004] This disclosure provides a repair method for electrically heated composite materials, which can significantly improve the repair effect of electrically heated composite materials.
[0005] This disclosure provides a repair method for an electrically heated composite material, the composite material comprising a damaged area and a non-damaged area. The repair method includes the following steps: preparing a repair material matching the size of the damaged area, the edge of the repair material having an outwardly extending conductive overlap; disconnecting the electrical connection between the damaged area and the non-damaged area, and exposing the heating resistance layer within the non-damaged area; laying the repair material on the damaged area, so that the conductive overlap forms an electrical connection with the heating resistance layer; placing a sealing material in the area where the repair material is laid and its surrounding area, so that the sealing material and the surface of the non-damaged area enclose a sealed cavity, and evacuating the sealed cavity; energizing a test circuit containing the repair material formed by the electrical connection, obtaining the temperature uniformity of the repair material surface, and determining whether the temperature uniformity of the repair material surface meets the target requirements; when the temperature uniformity meets the target requirements, injecting resin into the sealed cavity and curing it.
[0006] Optionally, the layered structure of the repair material is the same as that of the electrothermal composite material, and the constituent materials of the repair material are the same as those of the electrothermal composite material.
[0007] Optionally, disconnecting the electrical connection between the damaged partition and the undamaged partition includes: cutting or grinding to disconnect the heating resistance layer between the damaged partition and the undamaged partition.
[0008] Optionally, exposing the heating resistance layer within the undamaged partition includes: polishing the boundary region of the undamaged partition until the heating resistance layer within the undamaged partition is exposed.
[0009] Optionally, after exposing the heating resistance layer within the undamaged partition, the repair method further includes: using a multimeter to test the surface of the exposed heating resistance layer after polishing to ensure electrical continuity between any two points on the surface of the heating resistance layer.
[0010] Optionally, the step of obtaining the temperature uniformity of the repair material surface and determining whether the temperature uniformity of the repair material surface meets the target requirements includes: obtaining the temperature values of multiple measurement points on the repair material surface; determining whether the deviations of the temperature values of the multiple measurement points from the first preset temperature are all within a preset threshold; if yes, then it meets the requirements; if no, then it does not meet the requirements.
[0011] Optionally, the step of injecting resin into the sealed cavity and curing it includes: stopping the power supply to the test circuit, injecting resin when the temperature of the surface of the repair material drops to a second preset temperature; arranging a heating device and a heat preservation device, wherein the heating device and the heat preservation device completely cover the area corresponding to the sealed cavity; turning on the heating device; and heating and curing the sealed cavity at a third preset temperature.
[0012] Optionally, after injecting resin into the sealed cavity and curing it, the repair method further includes: polishing and finishing the surface of the cured repair area.
[0013] Optionally, the conductive overlap is made of a good conductor of metal, and under the same cross-sectional area, the resistance of the conductive overlap is less than or equal to the resistance of the heating resistance layer.
[0014] Optionally, the resin being infused is the same as or compatible with the matrix resin material of the electrically heated composite material.
[0015] The technical solution provided in this disclosure has at least the following advantages: The repair method for electrically heated composite materials disclosed herein achieves reliable electrical integration between the repair area and the original heating circuit by setting conductive overlaps at the edges of the repair material and directly electrically connecting the conductive overlaps to the exposed heating resistance layer in the undamaged zone. Furthermore, after repair but before resin injection, by energizing the test circuit containing the repair material and detecting the temperature uniformity of the repair material surface, it is possible to determine in time whether the electrothermal performance of the repair material meets the target requirements before sealing and curing. When the temperature uniformity meets the target requirements, resin is injected into the sealed cavity and cured, effectively avoiding local overheating or heating failure caused by poor overlap or material defects, and significantly improving the repair effect of electrically heated composite materials. Attached Figure Description
[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.
[0017] Figure 1 A partial structural schematic diagram of the electrically heated composite material provided in an embodiment of this disclosure; Figure 2 This is a schematic flowchart of a repair method for an electrically heated composite material provided in an embodiment of this disclosure.
[0018] Explanation of reference numerals in the attached figures: Damaged zone 1, Undamaged zone 2, Repair material 3, Conductive overlap 4, Heating resistance layer 5, Sealing material 6, Electric heating control system 7. Detailed Implementation
[0019] Currently, in existing repair methods for electrically heated composite materials, the electrically heated layer and matrix material in the damaged area are usually completely removed by grinding or laser cutting. Then, a homogeneous repair material that matches the size and structure of the ground area is embedded in the area, and the curing process is completed by vacuum infusion resin.
[0020] However, in practical applications, it has been found that while this method of complete removal and replacement can restore structural integrity, it is difficult to guarantee the electrical continuity between the repaired area and the original heating circuit. Specifically, because the original heating resistance layer is completely removed after grinding, the repair material and the original circuit rely only on physical bonding or non-conductive adhesive, resulting in high contact resistance and even the risk of open circuit at the interface. Even if some solutions attempt to achieve electrical connection by applying epoxy conductive adhesive or pre-embedding electrodes, it is still impossible to ensure the electrothermal stability under long-term service, and it is impossible to effectively verify the electrical performance before sealing and curing.
[0021] To address the aforementioned issues, this disclosure creatively proposes a method for repairing electrically heated composite materials: a conductive overlap is provided at the edge of the repair material, directly electrically connected to the exposed heating resistance layer in the undamaged zone; simultaneously, a sealed cavity is formed around the repair area, and a vacuum is first drawn before resin is injected; more importantly, before resin injection, the electrothermal performance is verified in advance by energizing a test circuit containing the repair material and detecting the surface temperature uniformity. When the temperature uniformity meets the target requirements, injection and curing are performed, significantly improving the repair effect of the electrically heated composite material.
[0022] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "multiple" means two or more, unless otherwise explicitly defined. Similarly, "multiple sets" refers to two or more sets (including two sets), and "multiple pieces" refers to two or more pieces (including two pieces).
[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0024] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.
[0025] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of this disclosure and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of this disclosure. For example, if the device or element in the illustration is inverted, then the element described as "below," "under," "below," or "bottom" of other elements or features will be oriented "above" or "top" of said other elements or features. Therefore, the term "below" may, depending on the context in which the term is used, encompass both above and below orientations, which will be obvious to those skilled in the art. Materials may be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein may be interpreted accordingly.
[0026] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.
[0027] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and area of the layers are enlarged for better understanding and ease of description. Furthermore, when describing a component as "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a portion of the edge of the entire surface.
[0028] In the description of the embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. The formation or placement of a second component above or on a first component, or on the surface of a first component, or on one side of a first component, may include embodiments where the first and second components are in direct contact, and may also include embodiments where an additional component may be placed between the first and second components, thereby preventing direct contact between the first and second components. For simplicity and clarity, various components may be drawn at different scales. In the drawings, some layers / components may be omitted for simplicity. Unless otherwise specified, the formation or placement of a second component on the surface of a first component refers to direct contact between the first and second components. The term "component" can refer to a layer, film, region, portion, structure, etc.
[0029] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.
[0030] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.
[0031] Figure 1 A partial structural schematic diagram of the electrically heated composite material provided in an embodiment of this disclosure; Figure 2 This is a schematic flowchart of a repair method for an electrically heated composite material provided in an embodiment of this disclosure.
[0032] This disclosure provides a method for repairing an electrically heated composite material. (See also...) Figure 1 The electrically heated composite material includes damaged zone 1 and undamaged zone 2.
[0033] refer to Figure 2 The repair method for electrically heated composite materials includes the following steps: S1, Prepare a repair material 3 that matches the size of the damaged partition 1. The edge of the repair material 3 is provided with an outwardly extending conductive overlap 4.
[0034] The conductive overlap part 4 serves as the electrical connection interface between the repair material 3 and the heating circuit of the electric heating composite material, enabling the repair material 3 to have a conductive structure that can be directly connected to the original circuit, avoiding reliance on external conductive adhesive or post-electrode, and simplifying the connection process.
[0035] S2, disconnect the electrical connection between damaged partition 1 and undamaged partition 2, and expose the heating resistance layer 5 in undamaged partition 2.
[0036] The purpose of this step is to isolate the faulty area, prevent the damaged zone 1 from interfering with the test circuit, such as short circuits or leakage, and ensure that the conductive overlap 4 can establish reliable contact with the heating resistance layer 5.
[0037] S3, the repair material 3 is laid on the damaged area 1, so that the conductive overlap 4 and the heating resistance layer 5 are electrically connected.
[0038] It should be noted that by directly connecting the materials, the repair material 3 becomes a continuation of the original heating circuit, restoring the overall electrothermal function. Compared with relying solely on bonding or non-conductive filling, this method can significantly reduce contact resistance and improve current transmission efficiency and heating uniformity.
[0039] S4, a sealing material 6 is installed in the area where the repair material 3 is laid and its surrounding area, so that the sealing material 6 and the surface of the undamaged partition 2 enclose a sealed cavity, and the sealed cavity is evacuated.
[0040] In some embodiments, a temperature sensor and a sealing material 6 required for the vacuum process are sequentially arranged on the repair material 3 and the electrically heated composite material. The sealing material 6 completely covers the repair material 3 and forms a sealed cavity with the surface of the undamaged partition 2. The sealed cavity is connected to a vacuum device and a filling device. The vacuum device is turned on to remove the gas in the sealed cavity, so that the repair material 3 and the surface of the undamaged partition 2 are tightly bonded, preventing bubbles or voids from forming after the resin cures. This improves the wettability, thermal conductivity and mechanical bonding strength of the repair interface, ensuring structural integrity and long-term service reliability.
[0041] S5, energize the test circuit containing the repair material 3 formed by electrical connection, obtain the temperature uniformity of the surface of the repair material 3, and determine whether the temperature uniformity of the surface of the repair material 3 meets the target requirements.
[0042] In some embodiments, the electrodes of the electrically heated composite material are connected to the electrically heated control system 7, the electrically heated control system 7 is turned on, and after the temperature of the surface of the repair material 3 stabilizes, the temperature uniformity of the surface of the repair material 3 is obtained, and it is determined whether the temperature uniformity of the surface of the repair material 3 meets the target requirements. If it does, step S6 is executed; if it does not, the process returns to S1.
[0043] Among them, if the temperature uniformity of the surface of repair material 3 meets the target requirements, the repair is successful; if it does not, the repair is unsuccessful. By testing the temperature distribution under actual power, the overlap quality and electrothermal performance of repair material 3 can be evaluated intuitively and quantitatively before resin injection. If there are poor overlaps, excessive contact resistance, or material defects, they will manifest as local overheating or cold areas, facilitating timely rework.
[0044] S6. When the temperature uniformity meets the target requirements, resin is injected into the sealed cavity and cured.
[0045] It is worth noting that final encapsulation is only completed after verification, which ensures the functional restoration of the repaired area and avoids material waste and repair difficulties caused by ineffective potting.
[0046] The repair method for electrically heated composite materials provided in this disclosure achieves reliable electrical integration between the repair area and the original heating circuit by setting a conductive overlap at the edge of the repair material and directly electrically connecting the conductive overlap to the exposed heating resistance layer in the undamaged zone. Furthermore, after the repair is completed but before resin injection, by energizing the test circuit containing the repair material and detecting the temperature uniformity of the repair material surface, it is possible to determine in time whether the electrothermal performance of the repair material meets the target requirements before sealing and curing. When the temperature uniformity meets the target requirements, resin is injected into the sealed cavity and cured, effectively avoiding local overheating or heating failure caused by poor overlap or material defects, and significantly improving the repair effect of the electrically heated composite material.
[0047] The embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings.
[0048] In some embodiments, the layered structure of the repair material 3 is the same as that of the electrothermal composite material, and the constituent materials of the repair material 3 are the same as those of the electrothermal composite material.
[0049] For example, the electroheating composite material includes a protective layer, an adhesive layer, a resin, and a heating resistance layer 5 stacked sequentially; correspondingly, the repair material 3 also includes a protective layer, an adhesive layer, a resin, and a heating resistance layer 5 stacked sequentially, and the material composition of each layer is consistent with that of the electroheating composite material. Therefore, the repair material 3 is highly compatible with the electroheating composite material in key physical properties such as coefficient of thermal expansion, electrical conductivity, dielectric properties, and mechanical modulus.
[0050] This design ensures good compatibility between the repair material 3 and the electrically heated composite material under a multi-field coupling environment of thermo-mechanical-electricity. On the one hand, it avoids thermal stress concentration or delamination at the interface due to material differences; on the other hand, it ensures that the repaired heating resistance layer 5 and the original heating resistance layer 5 have similar heating characteristics when energized, thereby guaranteeing the uniformity of the overall temperature field and improving the functional consistency and long-term service reliability of the repaired area.
[0051] In other embodiments, the layered structure of the repair material 3 may not include a protective layer on the lower surface of the electrically heated repair material 3 to reduce the thickness of the repair area.
[0052] In other embodiments, the conductive overlap portion 4 of the repair material 3 may overlap the heating resistance layer 5 of the repair material 3 during repair.
[0053] In some embodiments, disconnecting the electrical connection between damaged partition 1 and undamaged partition 2 includes cutting or grinding to disconnect the heating resistance layer 5 between damaged partition 1 and undamaged partition 2.
[0054] Specifically, the cutting method can be laser cutting, waterjet cutting, or mechanical milling, while the grinding method can be grinding with a grinding wheel, dressing with a grinding head, or sandblasting. During operation, the surface of the electrically heated composite material is locally removed along the boundary area of damaged partition 1 until the connection between the heating resistance layer 5 and the undamaged partition 2 is completely severed, thereby forming a clear electrical isolation gap between the two. This gap ensures that damaged partition 1 no longer participates in subsequent test circuits, effectively isolating the faulty area from interference with the performance of the repaired circuit, thus ensuring the accuracy of the test circuit and the integrity of the heating function after repair.
[0055] In some embodiments, exposing the heating resistance layer 5 within the undamaged partition 2 includes: polishing the boundary region of the undamaged partition 2 until the heating resistance layer 5 within the undamaged partition 2 is exposed.
[0056] Specifically, the grinding operation is performed on the edge area of the undamaged partition 2 near the damaged partition. Mechanical grinding or chemical etching can be used to remove the upper protective layer, adhesive layer, and resin layer by layer until the heating resistance layer 5 is completely exposed and its surface is clean, free of oxidation or contamination. The exposed heating resistance layer 5 area is used to directly contact the conductive overlap 4 at the edge of the repair material 3 to form a reliable electrical connection with low contact resistance. Because the exposed area is located in the undamaged partition 2, its electrothermal performance is stable and can serve as a high-quality connection benchmark, effectively improving the consistency and reliability of the overall electrothermal response after repair.
[0057] In some embodiments, after exposing the heating resistance layer 5 within the undamaged partition 2, the repair method further includes: using a multimeter to test the surface of the exposed heating resistance layer 5 after polishing to ensure electrical continuity between any two points on the surface of the heating resistance layer 5.
[0058] This operation is used to verify that the heating resistance layer 5 was not damaged during the polishing process, such as by breakage, localized ablation, or insulation contamination, and to confirm that the exposed heating resistance layer 5 still maintains complete electrical continuity.
[0059] This testing step can eliminate hidden circuit defects caused by excessive polishing or improper operation before the repair material 3 is laid, ensuring that the subsequent conductive overlap part 4 is connected to a fully functional heating path, thereby improving the reliability of the electrical connection.
[0060] In some embodiments, obtaining the temperature uniformity of the surface of the repair material 3 and determining whether the temperature uniformity of the surface of the repair material 3 meets the target requirements includes: obtaining the temperature values of multiple measurement points on the surface of the repair material 3; determining whether the deviations of the temperature values of the multiple measurement points from the first preset temperature are all within a preset threshold; if yes, then it meets the requirements; if no, then it does not meet the requirements.
[0061] Specifically, multiple measurement points are distributed in key areas on the surface of the repair material 3, including the central area, the edge area, and the position near the conductive overlap 4. Non-contact or contact temperature measurement can be performed by an infrared thermal imager or by arranging a thermocouple array.
[0062] The first preset temperature is the reference steady-state temperature reached by the undamaged zone 2 under the same energizing conditions. The preset threshold can be set according to material properties and application requirements, such as a relative deviation range of ±3℃ or ±5%. Only when the deviation between the measured temperature at all measurement points and the first preset temperature does not exceed this threshold is the heating of the repaired area considered uniform and the electrical connection reliable.
[0063] Through the above judgment mechanism, it is possible to accurately identify local overheating or insufficient heating caused by poor conductive bonding, excessive contact resistance, or internal defects in the repair material 3. This effectively avoids the risk of discovering functional failure only after curing and significantly improves the controllability and reliability of the repair process.
[0064] In some embodiments, injecting resin into the sealed cavity and curing it includes: stopping the power supply to the test circuit, injecting resin when the temperature of the surface of the repair material 3 drops to a second preset temperature; arranging a heating device and a heat preservation device that completely cover the area corresponding to the sealed cavity; turning on the heating device; and heating and curing the sealed cavity at a third preset temperature.
[0065] Specifically, the second preset temperature is a safe pouring temperature to avoid premature resin reaction or bubble formation at high temperatures, such as the glass transition temperature, typically set between 30°C and 50°C. The surface temperature of the repair material 3 is monitored in real time to ensure it cools to the second preset temperature before pouring begins. Heating equipment can be a heating blanket, a hot air circulation system, or an infrared heating plate; insulation devices can be heat insulation cotton, an insulation cover, or a vacuum bag sealing structure. These two components work together to create a uniform and stable thermal field. The third preset temperature is the corresponding curing temperature of the resin to ensure complete cross-linking and curing.
[0066] Optionally, a fan can be used to blow on the surface of the repair material 3 to accelerate the surface cooling rate.
[0067] For example, the second preset temperature can be set to room temperature. After determining that the temperature uniformity of the surface of the repair material 3 meets the target requirements, the electric heating control system 7 is turned off. When the surface temperature of the repair material 3 drops to room temperature, the injection equipment is turned on. When the injection material completely wets the repair material 3 and the sealed cavity, the injection is stopped.
[0068] Optionally, in some embodiments, the first preset temperature is set to not exceed the second preset temperature. After the electric heating system is powered off, the surface temperature of the repair material 3 is immediately within the pourable range, and the resin pouring operation can be performed immediately without additional cooling waiting. This setting significantly shortens the repair cycle and improves process efficiency; at the same time, it avoids the introduction of moisture, dust, or thermal stress due to forced cooling operations, such as blowing air or spraying cold air, which is beneficial to maintaining the cleanliness and interface stability of the repair area.
[0069] In some embodiments, after resin is injected into the sealed cavity and cured, the repair method further includes: polishing and finishing the surface of the cured repair area.
[0070] Specifically, grinding and finishing refers to smoothing the outer surface of the repair area after the resin has fully cured, using sandpaper, grinding discs, or CNC grinding equipment, so that its height is flush with the surface of the surrounding undamaged partition 2 or meets the preset tolerance range; the amount of material removed is controlled during the grinding process to avoid damaging the heating resistance layer 5 or conductive overlap 4 inside the repair material 3, and to ensure that the surface roughness meets the requirements of subsequent coating, film application, or pneumatic shaping.
[0071] In some embodiments, the conductive overlap portion 4 is made of a good metallic conductor material, and under the same cross-sectional area, the resistance of the conductive overlap portion 4 is less than or equal to the resistance of the heating resistance layer 5.
[0072] Specifically, the metallic good conductor materials include, but are not limited to, copper, aluminum, silver or their alloys, whose electrical conductivity is significantly higher than that of the carbon-based or metal mesh heating resistance layer 5 commonly used in composite materials. When the conductive overlap 4 and the heating resistance layer 5 have equal cross-sectional areas in the direction of current flow, the volume resistivity of the conductive overlap 4 is lower, thus ensuring that it will not become a high-resistance bottleneck in the current path. This allows the current to flow smoothly from the heating resistance layer 5 through the conductive overlap 4 into the heating structure of the repair material 3, avoiding Joule heat concentration at the overlap interface due to resistance abrupt changes, and ensuring the consistency of electrothermal performance between the repair area and the original heating circuit. At the same time, it avoids resin carbonization, interface debonding or long-term service failure caused by overheating of the overlap, significantly improving the electrical reliability and thermal stability of the repaired part.
[0073] In some embodiments, the resin being infused is the same as or compatible with the matrix resin material of the electrically heated composite material.
[0074] Specifically, the matrix resin is a polymer matrix that constitutes the main structure of the electrothermal composite material, such as epoxy resin, bismaleimide resin (BMI), polyimide, or vinyl ester resin. The infusion resin and the matrix resin are from the same chemical and curing system, and they are matched in terms of chemical structure, polarity, curing temperature, and coefficient of thermal expansion. This allows for good molecular diffusion and adhesion at the interface, with no obvious phase separation, delamination, or internal stress concentration. This ensures that the repaired area and the electrothermal composite material form a uniform and continuous matrix network after curing, effectively transferring loads and coordinating thermal deformation. At the same time, it avoids problems such as interface weakening, microcracks, or accelerated humid heat aging caused by resin incompatibility, thereby significantly improving the mechanical strength, environmental durability, and long-term service reliability of the repaired area.
[0075] The repair method for the electro-heated composite material provided in this disclosure achieves reliable electrical integration between the repair area and the original heating circuit by setting a conductive overlap at the edge of the repair material and directly electrically connecting the conductive overlap to the exposed heating resistance layer in the undamaged zone. Furthermore, after repair but before resin injection, by energizing a test circuit containing the repair material and detecting the temperature uniformity of the repair material surface, it is possible to determine whether the electrothermal performance of the repair material meets the target requirements before sealing and curing. If the temperature uniformity meets the target requirements, resin is injected into the sealed cavity and cured, effectively avoiding local overheating or heating failure caused by poor overlap or material defects, significantly improving the repair effect of the electro-heated composite material. Further, the repair material adopts the same layered structure and constituent materials as the original electro-heated composite material, ensuring a high degree of matching between the coefficient of thermal expansion, electrical conductivity, and mechanical properties, reducing interfacial stress and improving functional consistency. After exposing the heating resistance layer in the undamaged zone, a multimeter can be used to verify the electrical continuity of the heating resistance layer, eliminating the risk of hidden open circuits. In addition, the conductive overlap uses a metal conductor material with lower volume resistivity to avoid forming a bottleneck in the current path. In summary, this solution ensures the mechanical integrity of the repaired area while achieving high reliability and verifiability in restoring the electric heating function, significantly improving the overall repair effect of electric heating composite materials.
[0076] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.
Claims
1. A method for repairing electrically heated composite materials, characterized in that, The electrically heated composite material includes damaged zones and undamaged zones, and the repair method includes the following steps: Prepare a repair material that matches the size of the damaged area, wherein the edge of the repair material is provided with an outwardly extending conductive overlap. Disconnect the electrical connection between the damaged partition and the undamaged partition, and expose the heating resistance layer within the undamaged partition; The repair material is laid on the damaged area, so that the conductive overlap portion forms an electrical connection with the heating resistance layer; A sealing material is placed in the area where the repair material is laid and in its surrounding area, so that the sealing material and the surface of the undamaged partition form a sealed cavity, and the sealed cavity is evacuated. A test circuit containing the repair material, formed by the electrical connection, is energized to obtain the temperature uniformity of the surface of the repair material and to determine whether the temperature uniformity of the surface of the repair material meets the target requirements. When the temperature uniformity meets the target requirements, resin is injected into the sealed cavity and cured.
2. The repair method according to claim 1, characterized in that, The layered structure of the repair material is the same as that of the electrothermal composite material, and the constituent materials of the repair material are the same as those of the electrothermal composite material.
3. The repair method according to claim 1, characterized in that, Disconnecting the electrical connection between the damaged region and the undamaged region includes: The heating resistance layer between the damaged and undamaged zones is broken by cutting or grinding.
4. The repair method according to claim 1, characterized in that, The exposure of the heating resistance layer within the undamaged partition includes: The boundary area of the undamaged partition is polished until the heating resistance layer within the undamaged partition is exposed.
5. The repair method according to claim 4, characterized in that, After exposing the heating resistance layer within the undamaged partition, the repair method further includes: Use a multimeter to test the surface of the exposed heating resistor layer after polishing to ensure electrical continuity between any two points on the surface of the heating resistor layer.
6. The repair method according to claim 1, characterized in that, The step of obtaining the temperature uniformity of the repair material surface and determining whether the temperature uniformity of the repair material surface meets the target requirements includes: Obtain the temperature values at multiple measurement points on the surface of the repair material; Determine whether the deviations between the temperature values at the multiple measurement points and the first preset temperature are all within a preset threshold. If yes, then it conforms; if no, then it does not conform.
7. The repair method according to claim 1, characterized in that, The process of injecting and curing resin into the sealed cavity includes: Stop energizing the test circuit, and perform injection when the temperature of the repair material surface drops to the second preset temperature; Arrange heating equipment and insulation devices to completely cover the area corresponding to the sealed cavity. Turn on the heating equipment and heat and solidify the sealed cavity according to the third preset temperature.
8. The repair method according to claim 1, characterized in that, After the resin is injected into the sealed cavity and cured, the repair method further includes: The surface of the repaired area after curing is polished and repaired.
9. The repair method according to claim 1, characterized in that, The conductive overlap is made of a good metallic conductor, and under the same cross-sectional area, the resistance of the conductive overlap is less than or equal to the resistance of the heating resistance layer.
10. The repair method according to claim 1, characterized in that, The resin used for infusion is the same as or compatible with the matrix resin of the electrically heated composite material.