Repair method for composite material debonding

Abstract

The invention belongs to the technical field of composite material repairing, and discloses a repairing method for composite material debonding. Debonding positions between an upper skin and a sandwich, between the sandwich and an interlayer and between the sandwich and a lower skin of the composite material are determined, and a to-be-repaired area is delimited; a first injection hole and a first air hole are machined in the periphery of the to-be-repaired area, the first injection hole and the first air hole are communicated with the debonding gap, the first injection hole does not penetrate through the corresponding debonding interface layer, resin glue is injected through the first injection hole, curing is conducted after the resin glue overflows from the first air hole and is fully filled, and debonding interface bonding is achieved; a first through hole penetrating through the upper skin is machined in the to-be-repaired area, an L-shaped workpiece extends into the to-be-repaired area to remove a sandwich and an interlayer in the to-be-repaired area to form a concave cavity, and chippings are removed; pouring sealant is injected into the concave cavity and cured; and finally, the first through hole is expanded into a second through hole penetrating through the upper skin, the curing pouring sealant and the lower skin, and the gap of the wet installation fastening assembly is filled with the adhesive for fastening. And the comprehensive requirements of structure reinforcement, interface repair and sealing protection are met.

Description

Technical Field

[0001] This invention relates to the field of composite material repair technology, and in particular to a repair method for composite material debonding. Background Technology

[0002] Composite materials consist of an upper skin, a lower skin, and multiple sandwich structures. Each sandwich structure includes cores and partitions. The upper and lower skins are spaced apart, with multiple cores sandwiched between them. Partitions separate adjacent cores. The upper skin and cores, cores and partitions, and cores and lower skin are bonded and fixed together. Sandwich structures are widely used in composite material structures due to their advantages such as light weight, high bending stiffness, and high material utilization. Multi-layer sandwich structures can further improve load-bearing efficiency. However, during the manufacturing, assembly, and use of composite materials, problems such as skin and core damage, interface debonding, and separation between multiple cores can easily occur, leading to large-area debonding defects in severe cases. Within the structural repair tolerances, reasonable repair of debonding damage can ensure structural safety while reducing component replacement and maintenance costs.

[0003] Currently, existing sandwich structure repair technologies still have significant shortcomings: In traditional mechanical connection repairs, the tightening force of fasteners acts directly on the thin skin, which can easily cause skin damage or fastener loosening and failure, and it is difficult to prevent moisture from penetrating the core layer and causing corrosion damage; simple adhesive bonding repairs require a large bonding area, which carries the risk of insufficient bonding strength and weak bonding failure, and it is difficult to simultaneously meet the comprehensive requirements of structural reinforcement, interface repair, and sealing protection, and cannot meet the needs of efficient and reliable repair of debonding damage of multi-layer sandwich composite materials.

[0004] Therefore, there is an urgent need for repair methods to address the debonding of composite materials in order to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a repair method for debonding of composite materials, which is suitable for efficient and reliable repair of debonding damage of multi-layer sandwich composite materials, and can meet the comprehensive needs of structural reinforcement, interface repair and sealing protection, and conveniently and reliably restore the load transfer inside the composite material.

[0006] To achieve this objective, the present invention adopts the following technical solution: A method for repairing debonding of composite materials, wherein the composite material includes an upper skin, a lower skin, multiple cores, and multiple partitions, the upper skin and the lower skin are arranged at intervals, multiple cores are sandwiched between them, and a partition is provided between two adjacent cores. The upper skin and the cores, the cores and the partitions, and the cores and the lower skin are bonded and fixed to each other. The method for repairing debonding of composite materials includes the following steps: Step S100: Detect and determine the debonding location and debonding range between the upper skin and the core, the core and the partition, and the core and the lower skin, and delineate the area to be repaired; Step S200: Locate and process a first injection hole and a first vent hole around the area to be repaired. The first injection hole and the first vent hole are connected through the debonding gap formed by debonding. The first injection hole is opened to the position of the layer where the debonding interface is located and does not penetrate the debonding interface layer. Resin glue is injected into the debonding gap through the first injection hole. After the resin glue overflows from the first vent hole and it is confirmed that it is fully filled, the resin glue is cured to make the debonding interface bonded and fixed. Step S300: Locate the mechanical connection installation position in the area to be repaired, and machine a first through hole through the upper skin at the mechanical connection installation position; insert an L-shaped workpiece through the first through hole to remove the core and the partition material in the area to be repaired, forming a cavity, and remove debris; Step S400: Inject potting compound into the cavity through the first through hole, and cure the potting compound after confirming that it is fully filled. Step S500: At the mechanical connection installation position, enlarge the first through hole to the size of the second through hole. The size of the second through hole is smaller than the size of the area to be repaired. The second through hole penetrates the upper skin, the cured potting compound, and the lower skin. Wet install the mechanical connection fastening component at the second through hole. After filling the gap between the fastening component and the hole wall of the second through hole with adhesive, tighten it.

[0007] As an optional repair method for debonding composite materials, step S300 further includes: placing a positioning template with a hole diameter smaller than the first through hole on the upper skin to protect the upper skin; or, wrapping the part of the L-shaped workpiece in contact with the upper skin with an elastic material to protect the upper skin.

[0008] As an alternative repair method for debonding composite materials, in step S300, the radial diameter of the cavity is 20mm-50mm.

[0009] As an optional repair method for debonding of composite materials, step S400 further includes: distributing a plurality of second vent holes that communicate with the cavity circumferentially around the first through hole on the upper skin, and curing the potting compound after it overflows from all the second vent holes; the diameter of the second vent holes is less than or equal to 1.6 mm, and the second vent holes are located within a range of 0 mm to 6 mm from the outer edge of the area to be repaired.

[0010] As an alternative repair method for debonding of composite materials, in step S400, the potting compound is a structural adhesive or foam that has adhesive and reinforcing properties.

[0011] As an optional repair method for debonding composite materials, in step S500, the fastening assembly includes a screw, a nut, a first washer, and a second washer. The first washer is disposed on the outside of the upper skin, and the second washer is disposed on the outside of the lower skin. The shank of the screw passes through the first washer, the second through hole, and the second washer in sequence, and the head of the screw abuts against the first washer. The nut is threaded to the shank of the screw and abuts against the second washer.

[0012] As an alternative repair method for debonding composite materials, step S500 is followed by step S600, which involves cleaning the outer periphery of the screw head and sealing the screw head with sealant.

[0013] As an alternative repair method for debonding composite materials, the resin adhesive and the potting compound can be cured at different temperatures independently.

[0014] As an optional repair method for debonding composite materials, step S100 is directly connected to step S300, step S200 is omitted, and step S301 is included after step S300. Step S301: Inject the resin adhesive into the debonding interface in the cavity through the first through hole for local repair; enlarge the first through hole to the size of the second through hole at the mechanical connection installation position, the second through hole penetrating the upper skin and the lower skin; pre-install the fastening component in the second through hole in an untightened state, and then inject the potting adhesive into the cavity; tighten the fastening component, and use a heating device to heat conduct heat through the metal fastening component to cure the potting adhesive, and make the potting adhesive and the locally repaired resin adhesive cure simultaneously; steps S400 to S500 are omitted.

[0015] As an optional repair method for debonding composite materials, steps S100 to S200 are performed normally, and step S302 is included after step S300. Step S302: At the mechanical connection installation position, the first through hole is enlarged to the size of the second through hole, the second through hole penetrating the upper skin and the lower skin; the fastening component is pre-installed in the second through hole in an untightened state, and then the potting compound is injected into the cavity; the fastening component is tightened, and the potting compound is cured by heat conduction of the metal fastening component through a heating device; steps S400 to S500 are omitted.

[0016] The beneficial effects of this invention are: This invention provides a method for repairing debonding of composite materials. When repairing composite materials using this method, the location and extent of debonding between the upper skin and core, the core and partition, and the core and lower skin are first determined, and the area to be repaired is delineated. A first injection hole and a first vent hole are machined around the area to be repaired, both communicating with the debonding gap, with the first injection hole not penetrating the corresponding debonding interface layer. Resin is injected through the first injection hole, and after resin overflows from the first vent hole and fills it completely, it is cured, achieving bonding at the debonding interface. Subsequently, a first through hole penetrating the upper skin is machined within the area to be repaired. An L-shaped workpiece is inserted to remove the core and partition in the area to be repaired, forming a cavity and cleaning debris. A potting compound is injected into the cavity and cured. Finally, the first through hole is enlarged into a second through hole penetrating the upper skin, the cured potting compound, and the lower skin. A wet-installed fastening component is placed in the second through hole, and the gap is filled with adhesive for fastening. This composite material debonding repair method effectively solves the problems of skin damage, fastener loosening, and corrosion caused by moisture intrusion in traditional mechanical connection repairs. It also overcomes the shortcomings of simple adhesive repair, such as insufficient bonding strength and susceptibility to weak bond failure. The resin adhesive re-bonds the debonded interface, restoring the connection in the debonded area. The potting compound fills the cavity, preventing moisture and other liquids from entering the core and avoiding secondary damage caused by moisture or liquid erosion after repair. Mechanical reinforcement of the fastening components allows for convenient and reliable restoration of load transfer within the composite material. Simultaneously, the potting compound strengthens the circumferential area of ​​the fastening components, effectively preventing the risk of fastener detachment due to insufficient tightening force or further damage to the original structure due to excessive tightening force. This method comprehensively meets the needs of structural reinforcement, interface repair, and sealing protection, and is suitable for efficient and reliable repair of debonding damage in multi-layer sandwich composite materials, reducing component replacement and maintenance costs. Attached Figure Description

[0017] Figure 1 This is a first schematic diagram of step S200 of the repair method for debonding of composite materials according to an embodiment of the present invention; Figure 2 This is a second schematic diagram of step S200 of the repair method for debonding of composite materials according to an embodiment of the present invention; Figure 3 This is a third schematic diagram of step S200 of the repair method for debonding of composite materials according to an embodiment of the present invention; Figure 4 This is a fourth schematic diagram of step S200 of the repair method for debonding of composite materials according to an embodiment of the present invention; Figure 5 This is a top view of the composite material debonding repair method described in the embodiments of the present invention; Figure 6 This is a schematic diagram of step S300 of the repair method for debonding of composite materials according to an embodiment of the present invention; Figure 7 This is a schematic diagram of step S400 of the repair method for debonding of composite materials according to an embodiment of the present invention; Figure 8 This is a schematic diagram of step S500 of the repair method for debonding of composite materials according to an embodiment of the present invention.

[0018] In the picture: 10. Composite material; 101. Upper skin; 102. Lower skin; 103. Sandwich; 104. Partition; 11. Area to be repaired; 12. First injection hole; 13. First vent hole; 14. Debonding gap; 15. First through hole; 16. Cavity; 17. Second through hole; 18. Second vent hole; 21. Resin adhesive; 23. Potting compound; 31. L-shaped workpiece; 32. Fastening assembly; 321. Screw; 322. Nut; 323. First washer; 324. Second washer; 33. Positioning template; 34. Injector. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or 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 this invention according to the specific circumstances.

[0021] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1 like Figures 1 to 8 As shown, this embodiment provides a method for repairing debonding of composite materials. The composite material 10 includes an upper skin 101, a lower skin 102, multiple cores 103, and multiple partitions 104. The upper skin 101 and lower skin 102 are spaced apart vertically, with multiple cores 103 sandwiched between them. A partition 104 is provided between adjacent cores 103. The upper skin 101 and cores 103, cores 103 and partitions 104, and cores 103 and lower skin 102 are bonded and fixed to each other. The method for repairing debonding of the composite material includes the following steps: Step S100: Detect and determine the debonding positions and debonding ranges between the upper skin 101 and the core 103, the core 103 and the partition 104, and the core 103 and the lower skin 102, and delineate the area to be repaired 11; Step S200: Locate and process the first injection hole 12 and the first vent hole 13 around the area to be repaired 11. The first injection hole 12 and the first vent hole 13 are connected by the debonding gap 14 formed by debonding. The first injection hole 12 is opened to the position of the layer where the debonding interface is located and does not penetrate the debonding interface layer. Resin glue 21 is injected into the debonding gap 14 through the first injection hole 12. After the resin glue 21 overflows from the first vent hole 13 and it is confirmed that it is fully filled, the resin glue 21 is cured to make the debonding interface bonded and fixed. Step S300: Locate the mechanical connection installation position in the area to be repaired 11, and machine the first through hole 15 through the upper skin 101 at the mechanical connection installation position; insert the L-shaped workpiece 31 through the first through hole 15 to remove the core 103 and partition 104 material in the area to be repaired 11, forming a cavity 16, and remove debris. Step S400: Inject potting compound 23 into the cavity 16 through the first through hole 15, and cure the potting compound 23 after confirming that it is fully filled. Step S500: At the mechanical connection installation position, enlarge the first through hole 15 to the size of the second through hole 17. The size of the second through hole 17 is smaller than the size of the area to be repaired 11. The second through hole 17 passes through the upper skin 101, the cured potting compound 23 and the lower skin 102. Wet-install the mechanical connection fastening component 32 at the second through hole 17. After filling the gap between the fastening component 32 and the hole wall of the second through hole 17 with adhesive, tighten it.

[0024] When repairing composite material 10 using this composite material debonding repair method, firstly, the debonding positions and ranges between the upper skin 101 and the core 103, the core 103 and the partition 104, and the core 103 and the lower skin 102 of composite material 10 are determined, and the repair area 11 is delineated. A first injection hole 12 and a first vent hole 13 are machined around the repair area 11, both connected to the debonding gap 14, with the first injection hole 12 not penetrating the corresponding debonding interface layer. Resin 21 is injected through the first injection hole 12, and the first vent hole 13 is filled with resin 21. 1. After overflowing and filling fully, the material is cured to achieve bonding at the debonding interface. Then, a first through hole 15 is machined through the upper skin 101 in the area to be repaired 11. An L-shaped workpiece 31 is inserted to remove the core 103 and partition 104 in the area to be repaired 11 to form a cavity 16 and remove debris. The potting compound 23 is injected into the cavity 16 and cured. Finally, the first through hole 15 is enlarged into a second through hole 17 that penetrates the upper skin 101, the cured potting compound 23 and the lower skin 102. The fastening assembly 32 is wet-installed in the second through hole 17 and the gap is filled with adhesive for fastening. This composite material debonding repair method effectively solves the problems of skin damage, fastener loosening, and corrosion caused by moisture intrusion in traditional mechanical connection repairs. It also overcomes the shortcomings of simple adhesive repair, such as insufficient bonding strength and susceptibility to weak bond failure. Resin adhesive 21 bonds the debonded interface, restoring the connection in the debonded area. Potting compound 23 fills the cavity 16, preventing moisture and other liquids from entering the core 103 and avoiding secondary damage caused by moisture or liquid erosion after repair. The fastening component 32 provides mechanical reinforcement, enabling convenient and reliable restoration of load transfer within the composite material 10. Simultaneously, the potting compound 23 strengthens the circumferential area of ​​the fastening component 32, effectively preventing the fastening component 32 from falling off due to insufficient tightening force or the risk of further damage to the original structure due to excessive tightening force. This method achieves a comprehensive solution for structural reinforcement, interface repair, and sealing protection, providing efficient and reliable repair of debonding damage in composite materials 10 with multi-layer cores 103, and reducing component replacement and maintenance costs.

[0025] It is worth noting that step S300 can be placed before step S200. In this case, the first through hole 15 penetrates the upper skin 101, the core 103, and the partition 104, and the first through hole 15 serves as the first vent hole 13. The original first vent hole 13 is omitted. Resin glue 21 is injected into the debonding gap 14 through the first injection hole 12. After resin glue 21 overflows from the first through hole 15 and it is confirmed that the hole is fully filled, the resin glue 21 is cured to fix the debonding interface. There is no need to deal with the excess resin glue 21 in the cavity 16. The process can directly proceed to step S400. This process eliminates the need to process the first vent hole 13 separately, simplifies the unnecessary opening operation, improves repair efficiency, and the excess resin glue 21 directly participates in sealing and filling, forming a continuous and dense sealing structure with the subsequently injected potting compound 23, which significantly improves the overall sealing effect and structural integrity of the repaired area 11.

[0026] like Figures 1 to 4 As shown, in step S200, a syringe 34 is used to inject resin adhesive 21 into the debonding gap 14 through the first injection hole 12. The syringe 34 can precisely control the injection speed and amount of resin adhesive 21, so that the resin adhesive 21 smoothly fills the debonding gap 14, avoiding secondary damage to the composite material 10 caused by excessive injection pressure or uneven flow rate. At the same time, it improves the filling density and uniformity of resin adhesive 21, ensuring the stable and reliable bonding strength and repair quality of subsequent repairs.

[0027] It is worth noting that, such as Figures 1 to 2 As shown, in step S200, resin adhesive 21 is first injected into the debonding gap 14 through the first injection hole 12 using a syringe 34. Initially, the upper skin 101 is kept in a positive orientation with the lower skin 102 below, and the injection is completed from top to bottom. Figures 3 to 4 As shown, the composite material 10 is flipped over so that the upper skin 101 faces down and the lower skin 102 faces up. Injection continues from top to bottom to ensure that the resin adhesive 21 is fully impregnated and to achieve reliable bonding of each layer.

[0028] like Figure 5 As shown, in step S300, a first through hole 15 is machined through the upper skin 101 at the mechanical connection installation position. The diameter of the first through hole 15 is smaller than the diameter of the fastening component 32, and the axis of the first through hole 15 is perpendicular to the upper skin 101. Precise positioning of the subsequent machining position ensures the perpendicularity of the hole, providing a stable reference for subsequent hole enlargement, potting, and installation of the fastening component 32, thereby improving the overall strength of the repair structure. The diameter of the first through hole 15 can be 4mm, 5mm, 6mm, etc., and the positioning tolerance of the axis of the first through hole 15 relative to the perpendicular line of the upper skin 101 can be ±1mm, ±2mm, etc., without specific limitations here.

[0029] like Figure 6 As shown, step S300 further includes: placing a positioning template 33 with a hole diameter smaller than the first through hole 15 on the upper skin 101 to protect the upper skin 101; or, wrapping the part of the L-shaped workpiece 31 in contact with the upper skin 101 with an elastic material to protect the upper skin 101. These two methods can effectively protect the upper skin 101, preventing secondary damage such as scratches and pressure damage to the thinner upper skin 101 caused by the L-shaped workpiece 31 during the removal of the core 103 and the partition 104, ensuring the integrity of the upper skin 101, and laying a good foundation for subsequent repair processes.

[0030] In this embodiment, in step S300, the radial diameter of the cavity 16 is 20mm-50mm. On the one hand, this avoids the composite material 10 from being structurally weak due to an excessively large cavity 16, and from increasing costs due to excessive filling of the subsequent potting compound 23. On the other hand, the L-shaped workpiece 31 can effectively remove the damaged core 103 and spacer 104 material within the radial diameter range of 20mm-50mm, ensuring thorough damage removal while maintaining structural integrity and material utilization, thus improving the overall structural stability and economy of the repaired composite material 10. Optionally, the radial diameter of the cavity 16 can be 20mm, 30mm, 40mm, 50mm, etc., and is not specifically limited here.

[0031] In this embodiment, in step S300, tweezers and a vacuum cleaner are used to clean all the debris in the cavity 16, which can ensure that the inner surface of the cavity 16 is clean and free of impurities, avoid debris residue affecting the filling density and bonding strength of the potting compound 23, prevent the formation of gaps or weak areas, and provide a clean and reliable operating environment for subsequent potting, hole enlargement and mechanical connection.

[0032] like Figure 5 As shown, step S400 further includes: evenly distributing multiple second vent holes 18 communicating with the cavity 16 around the first through hole 15 on the upper skin 101; curing the potting compound 23 after it overflows from all the second vent holes 18; the diameter of the second vent holes 18 is less than or equal to 1.6 mm, and the second vent holes 18 are located within a range of 0 mm to 6 mm from the outer edge of the area to be repaired 11. The second vent holes 18 within a range of 0 mm to 6 mm from the outer edge of the area to be repaired 11 can expel air from the cavity 16, and the overflow of the potting compound 23 from all the second vent holes 18 confirms full filling and avoids void defects; at the same time, it prevents the second vent holes 18 from being too large and damaging the composite material 10, or too small and affecting venting, ensuring the curing effect of the potting compound 23 and improving the stability of the composite material 10 after repair.

[0033] like Figure 7 As shown, in this embodiment, in step S400, a syringe 34 is used to inject potting compound 23 into the cavity 16 through the first through hole 15. The syringe 34 can precisely control the injection rate and filling amount of the potting compound 23, so that the potting compound 23 evenly and densely fills the cavity 16, avoiding air bubbles or missing glue due to uneven pressure, improving the fullness of filling and the reliability of bonding, and ensuring the overall strength and stability of the repair area.

[0034] In this embodiment, in step S400, the potting compound 23 is a structural adhesive or foam that has adhesive and reinforcing functions. The structural adhesive or foam can form a stable supporting entity within the cavity 16, enabling reliable force transmission between the upper skin 101 and the lower skin 102, improving the overall stiffness and load-bearing capacity of the debonded area, while ensuring the interface bonding strength, avoiding internal voids and stress concentration, and improving the structural stability and service life of the repaired composite material 10.

[0035] In this embodiment, in step S500, the first through hole 15 is enlarged to a second through hole 17. For example, the first through hole 15 with a diameter of 5mm is enlarged to a second through hole 17 with a diameter of 7mm, and the axis of the second through hole 17 is perpendicular to the composite material 10. The second through hole 17 is then deburred and cleaned according to specifications. This ensures the precise assembly of the subsequent fastening components 32, improves the coaxiality of the installation and the uniformity of force distribution, avoids burrs and impurities affecting the bonding and connection reliability, and enhances the overall structural strength and repair stability of the composite material 10.

[0036] like Figure 8 As shown, in step S500, the fastening assembly 32 includes a screw 321, a nut 322, a first washer 323, and a second washer 324. The first washer 323 is disposed on the outer side of the upper skin 101, and the second washer 324 is disposed on the outer side of the lower skin 102. The shank of the screw 321 passes through the first washer 323, the second through hole 17, and the second washer 324 in sequence, and the head of the screw 321 abuts against the first washer 323. The nut 322 is threadedly connected to the shank of the screw 321 and abuts against the second washer 324. The fastening assembly 32 distributes the force on the surfaces of the upper skin 101 and the lower skin 102 through the first washer 323 and the second washer 324, avoiding local pressure loss and stress concentration. Together with the screw 321 and the nut 322, it achieves reliable locking from top to bottom, improves the overall connection rigidity and structural stability, reduces the risk of loosening and failure, and improves the durability and reliability of the repair structure.

[0037] In this embodiment, the head of screw 321 is placed on the upper skin 101; in other embodiments, the head of screw 321 can also be placed on the lower skin 102. The head of screw 321 can be placed on the side with higher aerodynamic shape requirements, and there is no specific limitation here.

[0038] In other embodiments, the fastening component 32 may also include a pin sleeve and a pin. The pin sleeve is disposed in the second through hole 17, and the pin passes through the pin sleeve and is respectively engaged with the upper skin 101 and the lower skin 102 to achieve mechanical fixation between the 10 layers of composite material. No specific limitation is made here.

[0039] In this embodiment, step S500 further includes: heating and curing the potting compound 23 using a heating blanket or heating lamp. This can accelerate the molding rate of the potting compound 23, shorten the overall repair cycle, enable the potting compound 23 to quickly reach stable strength, improve the bonding density with the surrounding structure, and at the same time ensure uniform and sufficient curing, reduce internal defects, and improve the structural stability and connection reliability of the repair area.

[0040] In this embodiment, step S500 is followed by step S600, in which the outer periphery of the screw head 321 is cleaned and the screw head 321 is sealed with sealant. Sealing the screw head 321 with sealant after cleaning effectively prevents external moisture and impurities from entering the composite material 10 through the gap between the screw 321 and the upper skin 101, avoiding moisture corrosion of the core 103 and the partition 104 or re-adhesion of the interface, improving overall sealing and protection performance and structural durability, and extending the service life of the composite material 10 after repair.

[0041] In this embodiment, the resin adhesive 21 and the potting compound 23 can each be cured independently at different temperatures, such as room temperature curing, medium temperature curing, or high temperature curing. The resin adhesive 21 and the potting compound 23 employ independent curing methods, allowing for flexible selection of room temperature curing, medium temperature curing, or high temperature curing based on the repair scenario, construction conditions, and structural requirements. This adapts to different working conditions and operating environments, improving construction adaptability and ease of operation, ensuring stable and reliable quality of interface bonding and cavity 16 potting, and enhancing overall repair efficiency and applicability.

[0042] In addition, resin glue 21 and potting glue 23 can be stored at room temperature without the need for low temperature or special protection conditions. This can effectively reduce equipment investment and energy consumption during material storage and transportation, simplify management processes, reduce additional operation and maintenance costs, improve construction convenience, and at the same time ensure stable material performance, providing economical and reliable material support for repair operations.

[0043] Example 2 This embodiment provides a repair method for debonding of composite materials. This repair method differs from Embodiment 1 in that steps S100 and S300 are directly connected, step S200 is omitted, and step S301 is included after step S300. Step S301: Resin adhesive 21 is injected into the debonded interface in the cavity 16 through the first through hole 15 for local repair; the first through hole 15 is enlarged to the size of the second through hole 17 at the mechanical connection installation position, the second through hole 17 penetrating the upper skin 101 and the lower skin 102; the fastening component 32 is pre-installed in the second through hole 17 in an untightened state, and then potting compound 23 is injected into the cavity 16; the fastening component 32 is tightened, and the potting compound 23 is cured by heat conduction through the metal fastening component 32 using a heating device, and the potting compound 23 and the locally repaired resin adhesive 21 are cured synchronously; steps S400 to S500 are omitted.

[0044] This process simplifies the repair procedures and shortens the construction cycle. It simultaneously repairs the debonded interface with resin adhesive 21, fills and reinforces with potting compound 23, and mechanically connects with fastening component 32, achieving integrated molding of adhesive repair and mechanical reinforcement. The simultaneous curing of resin adhesive 21 and potting compound 23 improves the reliability of the interface bonding. The potting compound 23 is cured by heat conduction through the metal fastening component 32 using a heating device, which can achieve uniform heat conduction to the inside of the cavity 16, ensuring that the potting compound 23 is fully cured and consistent inside and out. This optimizes the operation process, improves the repair efficiency and adaptability of the debonded damage of the composite material 10 of the multi-layer sandwich core 103, saves repair time, and improves repair quality.

[0045] It is worth noting that in this embodiment, because the outer diameter of the fastening component 32 is compatible with the second through hole 17, it is difficult to directly inject the potting compound 23 into the cavity 16 through the second through hole 17. Therefore, a second injection hole can be separately opened on the upper skin 101, and the potting compound 23 can be injected into the cavity 16 through this second injection hole; or a fastening component 32 with a built-in third injection hole can be selected, and the potting compound 23 can be injected into the cavity 16 through its third injection hole. This ensures that the potting compound 23 smoothly and fully fills the cavity 16, improves the convenience of the injection construction and the filling density, and ensures the overall sealing effect and structural integrity of the repaired area 11.

[0046] Example 3 This embodiment provides a repair method for composite material debonding. The difference between this repair method and Embodiment 1 is that steps S100 to S200 are performed normally, and step S302 is added after step S300. Step S302: At the mechanical connection installation position, the first through hole 15 is enlarged to the size of the second through hole 17, and the second through hole 17 penetrates the upper skin 101 and the lower skin 102; the fastening component 32 is pre-installed in the second through hole 17 in an untightened state, and then potting compound 23 is injected into the cavity 16; the fastening component 32 is tightened, and the potting compound 23 is cured by heat conduction of the metal fastening component 32 through a heating device; steps S400 to S500 are omitted.

[0047] This process uses a heating device to conduct heat and cure the potting compound 23 with the help of a metal fastening component 32. This allows heat to be evenly conducted into the cavity 16, ensuring that the potting compound 23 is fully cured and consistent inside and out. This improves the bonding and reinforcement quality, ensures that the structure is dense and defect-free, enhances the overall repair reliability and structural stability, saves repair time, and improves repair quality.

[0048] It is worth noting that in this embodiment, because the outer diameter of the fastening component 32 is compatible with the second through hole 17, it is difficult to directly inject the potting compound 23 into the cavity 16 through the second through hole 17. Therefore, a second injection hole can be separately opened on the upper skin 101, and the potting compound 23 can be injected into the cavity 16 through this second injection hole; or a fastening component 32 with a built-in third injection hole can be selected, and the potting compound 23 can be injected into the cavity 16 through its third injection hole. This ensures that the potting compound 23 smoothly and fully fills the cavity 16, improves the convenience of the injection construction and the filling density, and ensures the overall sealing effect and structural integrity of the repaired area 11.

[0049] Example 4 This embodiment provides a repair method for debonding of composite materials. The difference between this repair method and Embodiment 1 is that when the debonding area of ​​composite material 10 is small, only steps S100 and S200 can be performed to repair it by injection bonding; or only steps S300 to S500 can be performed to repair it by combining potting repair and wet installation mechanical connection repair.

[0050] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A repair method for debonding of composite materials, wherein the composite material (10) includes an upper skin (101), a lower skin (102), multiple cores (103), and multiple partitions (104), wherein the upper skin (101) and the lower skin (102) are arranged vertically at intervals, and multiple cores (103) are sandwiched between them, and a partition (104) is provided between two adjacent cores (103), wherein the upper skin (101) and the cores (103), the cores (103) and the partitions (104), and the cores (103) and the lower skin (102) are bonded and fixed to each other, characterized in that, The repair method for the debonding of the composite material includes the following steps: Step S100: Detect and determine the debonding position and debonding range between the upper skin (101) and the core (103), the core (103) and the partition (104), and the core (103) and the lower skin (102), and delineate the area to be repaired (11). Step S200: Locate and process a first injection hole (12) and a first vent hole (13) around the area to be repaired (11). The first injection hole (12) and the first vent hole (13) are connected by a debonding gap (14) formed by debonding. The first injection hole (12) is opened to the position of the layer where the debonding interface is located and does not penetrate the debonding interface layer. Resin glue (21) is injected into the debonding gap (14) through the first injection hole (12). After the resin glue (21) overflows from the first vent hole (13) and it is confirmed that it is fully filled, the resin glue (21) is cured to make the debonding interface bonded and fixed. Step S300: Locate the mechanical connection installation position in the area to be repaired (11), and machine a first through hole (15) through the upper skin (101) at the mechanical connection installation position; insert an L-shaped workpiece (31) through the first through hole (15) to remove the material of the core (103) and the partition (104) in the area to be repaired (11), forming a cavity (16), and remove debris; Step S400: Inject potting compound (23) into the cavity (16) through the first through hole (15), and cure the potting compound (23) after confirming that it is fully filled. Step S500: At the mechanical connection installation position, the first through hole (15) is enlarged to the size of the second through hole (17), the size of the second through hole (17) is smaller than the size of the area to be repaired (11), and the second through hole (17) penetrates the upper skin (101), the cured potting compound (23) and the lower skin (102); a mechanical connection fastening assembly (32) is wet-installed at the second through hole (17), and the gap between the fastening assembly (32) and the hole wall of the second through hole (17) is filled with adhesive and then fastened.

2. The repair method for debonding of composite materials according to claim 1, characterized in that, Step S300 further includes: placing a positioning template (33) with a hole diameter smaller than the first through hole (15) on the upper skin (101) to protect the upper skin (101); or, wrapping the part of the L-shaped workpiece (31) that contacts the upper skin (101) with an elastic material to protect the upper skin (101).

3. The repair method for debonding of composite materials according to claim 1, characterized in that, In step S300, the radial diameter of the cavity (16) is 20mm-50mm.

4. The repair method for debonding of composite materials according to claim 1, characterized in that, Step S400 further includes: distributing a plurality of second vent holes (18) that communicate with the cavity (16) circumferentially around the first through hole (15) on the upper skin (101), and curing the potting compound (23) after it overflows from all the second vent holes (18); the diameter of the second vent holes (18) is less than or equal to 1.6 mm, and the second vent holes (18) are located within a range of 0 mm to 6 mm from the outer edge of the area to be repaired (11).

5. The repair method for debonding of composite materials according to claim 1, characterized in that, In step S400, the potting compound (23) is a structural adhesive or foam adhesive that has bonding and reinforcing effects.

6. The repair method for debonding of composite materials according to claim 1, characterized in that, In step S500, the fastening assembly (32) includes a screw (321), a nut (322), a first washer (323), and a second washer (324). The first washer (323) is disposed on the outside of the upper skin (101), and the second washer (324) is disposed on the outside of the lower skin (102). The shank of the screw (321) passes through the first washer (323), the second through hole (17), and the second washer (324) in sequence, and the head of the screw (321) abuts against the first washer (323). The nut (322) is threadedly connected to the shank of the screw (321) and abuts against the second washer (324).

7. The repair method for debonding of composite materials according to claim 6, characterized in that, The step S500 is followed by a step S600, in which the outer periphery of the head of the screw (321) is cleaned and the head of the screw (321) is sealed with sealant.

8. The repair method for debonding of composite materials according to any one of claims 1-7, characterized in that, The resin adhesive (21) and the potting compound (23) can each be cured at different temperatures independently.

9. The repair method for debonding of composite materials according to any one of claims 1-7, characterized in that, Step S100 is directly connected to step S300, step S200 is omitted, and step S301 is included after step S300; Step S301: Inject the resin adhesive (21) into the debonding interface in the cavity (16) through the first through hole (15) for local repair; enlarge the first through hole (15) to the size of the second through hole (17) at the mechanical connection installation position, the second through hole (17) penetrates the upper skin (101) and the lower skin (102); first, pre-install the fastening component (32) in the second through hole (17) in an untightened state, and then inject the potting adhesive (23) into the cavity (16); tighten the fastening component (32), and use the heating device to conduct heat through the fastening component (32) made of metal to cure the potting adhesive (23), and make the potting adhesive (23) and the locally repaired resin adhesive (21) cure synchronously; steps S400 to S500 are omitted.

10. The repair method for debonding of composite materials according to any one of claims 1-7, characterized in that, Steps S100 to S200 are performed normally, and step S302 is included after step S300. Step S302: At the mechanical connection installation position, the first through hole (15) is enlarged to the size of the second through hole (17), the second through hole (17) penetrates the upper skin (101) and the lower skin (102); the fastening component (32) is pre-installed in the second through hole (17) in an untightened state, and then the potting compound (23) is injected into the cavity (16); the fastening component (32) is tightened, and the potting compound (23) is cured by heat conduction of the metal fastening component (32) through the heating device; steps S400 to S500 are omitted.

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