Glue injection repairing method for foam sandwich structural member

Abstract

The invention discloses a glue injection repairing method for a foam sandwich structural member. The glue injection repairing method comprises the steps that S1, a degumming area of the foam sandwich structural member is determined; s2, drilling a plurality of glue overflow holes in the degumming area, and drilling a plurality of glue injection holes in the edge of the degumming area; s3, a breathable layer and a vacuum layer which cover the multiple glue overflowing holes are sequentially arranged on the degumming area, a vacuum device is connected with a cavity, communicated with the glue overflowing holes, on the inner side of the vacuum layer, a fence arranged around the glue injection holes is arranged on the outer sides of the glue injection holes, and a glue storage pool communicated with the glue injection holes is formed in the fence; s4, preparing a glue solution, fully filling the glue storage pool with the glue solution, and enabling the glue solution in the glue storage pool to flow to the glue overflow hole along the gap at the debonding part through the glue injection hole by utilizing the vacuumizing suction of the vacuum device until the glue solution overflows from the glue overflow hole; according to the method, the vacuum technology is adopted, glue liquid can better permeate into degummed gaps, the phenomenon of non-bonding or weak bonding of local parts of a repaired product is avoided, and it is guaranteed that the repaired structure has good performance and reliability.

Description

Technical Field

[0001] The invention relates to the technical field of glue injection repair of foam sandwich structure parts, and in particular to a glue injection repair method of foam sandwich structure parts. Background Art

[0002] Foam sandwich structures are a special type of composite structure that consists of two thinner panels (or skins) with a thicker foam core in between. This structure is designed to provide high specific stiffness (i.e. stiffness relative to weight) and is commonly used in applications that require light weight, high strength and rigidity, such as aerospace, automotive industry, shipbuilding and wind energy industry.

[0003] In view of the debonding phenomenon between the skin and the foam plastic core of the foam sandwich structure, the existing glue injection repair process operation method is as follows: 1. Drill a number of 2.1 mm glue injection holes and overflow holes from the edge of the defect in a staggered manner in the center and periphery of the debonding area to make them communicate with the debonding area; 2. Use a syringe to inject epoxy glue from the glue injection hole until the glue overflows from the surrounding overflow holes, then use transparent tape to block the overflow holes, and then wait for the glue to solidify. For example, a single closed-cavity foam sandwich structure damage repair method provided by publication number CN113977993A includes: determining the fault area of ​​the blade; wherein the fault area includes the debonding area; uniformly setting glue injection holes in the fault area; injecting a preset amount of repair glue into the glue injection hole based on the total glue injection amount; wherein the total glue injection amount is determined based on the weight of the blade; pressurizing and statically placing the fault area of ​​the blade based on the skin repair tool; the foam sandwich structure damage repair mainly uses a syringe, and uses a syringe to inject repair glue into the fault area along the glue injection hole.

[0004] The above-mentioned prior art has problems during implementation: due to the narrow gap between the skin and the foam plastic debonding area, the glue cannot spread after injection, and there is a problem that the epoxy glue cannot be effectively injected into the debonding area, resulting in local non-bonding or weak bonding of the product after repair, making the product prone to debonding again after a period of use. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned technical deficiencies and propose a method for repairing foam sandwich structures by injecting glue, so as to solve the problem that the epoxy glue cannot be effectively injected into the debonded part in the prior art repair method, resulting in the phenomenon of partial non-bonding or weak bonding of the product after repair, making the product easy to debond again after a period of use.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: The present invention provides a method for repairing a foam sandwich structure by injecting glue, comprising: S1: providing a foam sandwich structure, and determining a debonding area of ​​the foam sandwich structure; S2: drilling a plurality of overflow holes in the debonding area, and drilling a plurality of injection holes at the edge of the debonding area, wherein the injection holes are connected to the debonding part of the foam sandwich structure; S3: sequentially arranging a breathable layer and a vacuum layer covering a plurality of overflow holes on the degumming area, connecting a vacuum device to a chamber inside the vacuum layer that is connected to the overflow holes, arranging a fence around the injection holes outside the injection holes, and forming a glue storage pool connected to the injection holes inside the fence; S4: preparing glue liquid, filling the glue storage tank with glue liquid, and using the vacuum suction of the vacuum device to make the glue liquid in the glue storage tank flow through the glue injection hole along the gap at the debonding point to the glue overflow hole, until the glue liquid overflows from the glue overflow hole; S5: Seal and press the repair area until the glue cures.

[0007] In some embodiments, step S1 includes: using a tapping inspection or an acoustic vibration method to determine the damage degree of the debonding area, and using a marker to draw the damage boundary.

[0008] In some embodiments, the glue injection holes and the glue overflow holes are arranged in a staggered manner, the diameter of the glue injection holes is 2 mm, the diameter of the glue overflow holes is 1.5 mm, and the hole spacing between each of the glue injection holes and each of the glue overflow holes is about 10 mm-15 mm.

[0009] In some embodiments, the breathable layer includes breathable felt and a porous isolation membrane, the vacuum layer includes a vacuum bag film, and the edge of the vacuum bag film is sealed to the surface of the foam sandwich structure by a first sealing tape; the enclosure is formed by a second sealing tape arranged around the glue injection hole; the vacuum device includes a vacuum generator and an air compressor.

[0010] In some embodiments, step S3 includes: laying a perforated isolation film, a breathable felt and a vacuum bag film in sequence on the surface of the glue overflow hole, so that the perforated isolation film, the breathable felt and the vacuum bag film cover each glue overflow hole, connecting the vacuum generator to the air compressor, placing the vacuum generator base on the breathable felt, so that the vacuum generator is connected to the chamber formed between the breathable felt and the vacuum bag film, and then making a vacuum bag, and sealing the edge of the vacuum bag film to the surface of the foam sandwich structure through a first sealing tape; using a second sealing tape to make a fence around each glue injection hole, the fence surrounds the glue injection hole to form a number of glue storage pools.

[0011] In some embodiments, the adhesive is an epoxy resin adhesive, and the epoxy resin adhesive is prepared by mixing 650 low molecular weight polyamide resin and WSR6101 bisphenol A epoxy resin in a mass ratio of 1:1.

[0012] In some embodiments, during glue injection, a hot air gun is used to assist in heating the repair area; during operation, the hot air gun is held so that an angle less than 90° is formed between the hot air gun and the damaged skin, the air outlet of the hot air gun is 5cm-15cm away from the skin, and the air outlet temperature of the hot air gun is 55℃-70℃.

[0013] In some embodiments, step S5 includes: after glue overflows from the glue overflow hole, removing the breathable layer and the vacuum layer, using ethyl acetate to wipe off the glue overflowing from the skin, covering the skin surface in the repair area with a non-porous separation film, and fixing the non-porous separation film with transparent tape, then placing sandbags above the repair area, using the sandbags' own gravity to press the repair area, and placing the foam sandwich structure in an environment of 25°C-30°C for 72 hours until the glue solidifies.

[0014] In some embodiments, after step S5, step S6 is further included: after the glue liquid is solidified, the transparent tape is torn off, and the glue overflow hole and the glue injection hole are sealed with epoxy resin.

[0015] In some embodiments, after step S5, step S7 is further included: inspecting the repaired area using a non-destructive testing method.

[0016] Compared with the prior art, the glue injection repair method for foam sandwich structural parts provided by the present invention designs glue injection holes and glue overflow holes. The glue injection holes are used for injecting glue, and the flow of glue can be observed through the glue overflow holes. The air inside the sandwich structure can also be removed to prevent the formation of bubbles during the curing process. A breathable layer and a vacuum layer are sequentially arranged on the debonding area, and the breathable layer and the vacuum layer both cover a number of glue overflow holes. After the glue storage tank is filled with glue, the vacuum suction force generated by the vacuum device can make the glue in the glue storage tank flow through the glue injection holes along the gaps at the debonding location to the glue overflow holes, and the air inside the foam sandwich structural part can be discharged through the breathable layer to the chamber inside the vacuum layer. The vacuum technology can be used to discharge the air inside the vacuum layer out of the vacuum layer, so that a negative pressure is formed in the vacuum layer. Pressure can provide uniform pressure for the debonding area of ​​the foam sandwich structure, so that the glue can better penetrate into the debonding gap, ensuring that the glue is evenly distributed and completely infiltrates the interior of the structure, and can effectively complete the glue injection repair of the foam sandwich structure to avoid the phenomenon of local non-bonding or weak bonding of the product after repair, and ensure that the repaired structure has good performance and reliability; through the design of the glue storage tank, it can be guaranteed that there is enough glue supply during the glue injection process. At the same time, after the glue storage tank is filled with glue, the glue injection hole can be closed. Under vacuum conditions, the interior of the foam sandwich structure is a low-pressure environment, which produces a pressure difference with the external gas. This pressure difference helps the glue to quickly and evenly penetrate into the interior of the structure, and the internal and external pressure difference can be used to promote the flow of glue. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1is a flow chart of a method for repairing a foam sandwich structure by injecting glue provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of the main structure of a foam sandwich structure member in a method for repairing a foam sandwich structure member by injecting glue provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of the top view of the structure of a foam sandwich structure member according to the method for repairing a foam sandwich structure member by injecting glue provided by an embodiment of the present invention; Figure 4 It is a schematic diagram of the main structure of the glue injection repair method for a foam sandwich structure provided by an embodiment of the present invention during the glue injection process; Figure 5 It is a schematic diagram of the structure of the top view during the glue injection of the glue injection repair method for the foam sandwich structure provided by the embodiment of the present invention; Figure 6 It is a schematic diagram of the main structure of the foam sandwich structure component during curing according to the glue injection repair method provided by the embodiment of the present invention; Figure 7 It is a schematic diagram of the top view of the structure of the foam sandwich structure component during curing according to the glue injection repair method provided by the embodiment of the present invention; Figure 8 The present invention is a simplified flowchart of a method for repairing a foam sandwich structure by injecting glue according to an embodiment of the present invention.

[0018] Description of reference numerals: 1. Air compressor; 2. Vacuum generator; 3. Vacuum bag film; 4. Breathable felt; 5. Perforated isolation film; 6. First sealing tape; 7. Second sealing tape; 8. Epoxy resin glue; 9. Skin; 10. Foam core; 11. Glue injection hole; 12. Glue overflow hole; 13. Non-porous separation film; 14. Transparent tape; 15. Sandbag. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] In order to solve the problem that epoxy glue cannot be effectively injected into the debonded area in the glue injection repair method, resulting in the phenomenon of local non-bonding or weak bonding of the product after the repair, and the technical problem that the product is prone to debonding again after being used for a period of time, the present invention provides a glue injection repair method for foam sandwich structural parts. The vacuum technology is used to discharge the air inside the vacuum bag out of the vacuum bag to form a negative pressure in the vacuum bag, which can provide uniform pressure for the debonded area of ​​the foam sandwich structural part, so that the glue can better penetrate into the debonded gap, ensuring that the glue is evenly distributed and completely infiltrates the interior of the structure. The glue injection repair of the foam sandwich structural part can be effectively completed, avoiding the phenomenon of local non-bonding or weak bonding of the product after the repair, and ensuring that the repaired structure has good performance and reliability.

[0021] It should be noted that the glue injection repair method for foam sandwich structures described in the present invention is used for but not limited to glue injection repair of foam sandwich structures. For the sake of convenience, in the present invention, only the application of the glue injection repair method for foam sandwich structures to glue injection repair of foam sandwich structures is taken as an example for explanation. The principle of applying the glue injection repair method for foam sandwich structures to the glue injection of other types of structural parts is substantially the same as the principle applied to the glue injection repair of foam sandwich structures, and will not be elaborated here.

[0022] See also Figures 1 to 7 , a method for repairing foam sandwich structure parts by injection molding, including: S1: providing a foam sandwich structure, and determining a debonding area of ​​the foam sandwich structure; S2: drilling a plurality of glue overflow holes 12 in the debonding area, and drilling a plurality of glue injection holes 11 at the edge of the debonding area, wherein the glue injection holes 11 are connected to the debonding part of the foam sandwich structure; S3: sequentially arranging a breathable layer and a vacuum layer covering a plurality of overflow holes 12 in the degumming area, connecting a vacuum device to a chamber inside the vacuum layer that is connected to the overflow hole 12, arranging an enclosure around the injection hole 11 outside the injection hole 11, and forming a glue storage pool connected to the injection hole 11 inside the enclosure; S4: Prepare glue liquid, fill the glue storage tank with glue liquid, and use the vacuum suction of the vacuum device to make the glue liquid in the glue storage tank flow through the glue injection hole 11 along the gap at the debonding position to the glue overflow hole 12 until the glue liquid overflows from the glue overflow hole 12; S5: Seal and press the repair area until the glue cures.

[0023] In this scheme, after determining the degumming area, a plurality of glue injection holes 11 are drilled on the edge of the degumming area to facilitate the injection of glue through the glue injection holes 11, and a plurality of glue overflow holes 12 are drilled in the degumming area so that the flow of glue can be observed through the glue overflow holes 12, and the air inside the sandwich structure can be excluded to prevent the formation of bubbles during the curing process; a breathable layer and a vacuum layer are sequentially arranged on the degumming area, and both the breathable layer and the vacuum layer cover the plurality of glue overflow holes 12. After the glue storage tank is filled with glue, the vacuum suction generated by the vacuum device can make the glue in the glue storage tank pass through the glue injection holes 11 along the glue overflow holes 12. The glue flows along the gap at the debonding point to the glue overflow hole 12, and the air inside the foam sandwich structure can be discharged through the breathable layer to the chamber inside the vacuum layer. The vacuum technology can be used to discharge the air inside the vacuum layer out of the vacuum layer, so that negative pressure is formed in the vacuum layer. This can provide uniform pressure for the debonding area of ​​the foam sandwich structure, so that the glue can better penetrate into the debonding gap, ensuring that the glue is evenly distributed and completely infiltrates the interior of the structure. The glue injection repair of the foam sandwich structure can be effectively completed, ensuring that the repaired structure has good performance and reliability.

[0024] In this embodiment, step S1 includes: determining the damage degree of the debonding area by means of tapping inspection or acoustic vibration, and drawing the damage boundary with a marker.

[0025] Among them, after the degree of damage of the debonding area is determined by tapping inspection or acoustic vibration, the debonding area that needs to be repaired can be determined according to the degree of damage to the structural part. The tapping inspection usually uses a small hammer or similar tool to gently tap the surface of the structural part, and the damage is judged according to the tapping sound. The method of acoustic vibration detection is: the acoustic emission signal collected by the sensor is analyzed by special equipment, and then the degree and location of the damage are judged according to the signal characteristics (such as frequency, amplitude, etc.). Drawing the damage boundary is convenient for the subsequent laying of the porous isolation membrane 5, breathable felt 4 and vacuum bag membrane 3 according to the marking line.

[0026] It should be noted that the foam sandwich structure consists of two thinner skins 9 and a thicker foam core 10 sandwiched between the two skins 9. The glue injection holes 11 and the glue overflow holes 12 are drilled from the surface of the skin 9 to the middle. The depths of the glue injection holes 11 and the glue overflow holes 12 depend on the specific structural design and process requirements. It is necessary to ensure that the filling material can be evenly distributed inside the entire structure and can effectively discharge air and other excess materials.

[0027] In order to ensure uniform distribution of the glue, in some embodiments, refer to Figure 2 and Figure 3The injection holes 11 and the overflow holes 12 are arranged in a staggered manner. The diameter of the injection holes 11 is 2 mm, and the diameter of the overflow holes 12 is 1.5 mm. The hole spacing between each injection hole 11 and each overflow hole 12 is about 10 mm-15 mm to ensure that the glue can flow fully and exhaust the air, while also avoiding material waste or unnecessary accumulation due to too close a distance.

[0028] It should be noted that in other possible embodiments, there is no limitation on the distance between the injection hole 11 and the overflow hole 12 and the size of the injection hole 11 and the overflow hole 12, which depends on factors such as the geometry and thickness of the structural component and the properties of the glue used.

[0029] Preferably, in this embodiment, please refer to Figure 4 and Figure 5 The breathable layer includes a breathable felt 4 and a porous isolation membrane 5, the vacuum layer includes a vacuum bag film 3, the edge of the vacuum bag film 3 is sealed and connected to the surface of the foam sandwich structure through a first sealing tape 6, the breathable felt 4 and the porous isolation membrane 5 are laid flat between the vacuum bag film 3 and the foam sandwich structure; the enclosure is formed by a second sealing tape 7 arranged around the injection hole 11; the vacuum device includes a vacuum generator 2 and an air compressor 1.

[0030] The vacuum bag film 3 is made of materials such as polyester film (PET) or polyimide film (PI), and is used to cover the debonding area of ​​the foam sandwich structure. Its function is to create a sealed environment. By vacuuming, the atmospheric pressure can be converted into inward pressure, which helps the glue to penetrate into every gap of the foam sandwich structure, remove air, reduce bubbles in the product, and ensure that the glue can fully infiltrate the interior of the structure. The breathable felt 4 is made of short-cut fibers or non-woven fabrics and has good air permeability. It can help exhaust the air in the foam sandwich structure, prevent the formation of bubbles, ensure the uniform distribution of the glue on the foam sandwich structure, and prevent problems caused by too much or too little glue in local areas. The porous isolation film 5 is a film with small holes, made of materials such as polyethylene (PE) or polypropylene (PP), and is used to provide a layer of isolation between the foam sandwich structure and the breathable felt and vacuum bag film surface to prevent adhesion and facilitate the removal of the vacuum bag film and breathable felt. The small holes of the porous isolation film 5 allow gas and glue to pass through, which helps the exhaust and overflow process.

[0031] In this embodiment, step S3 includes: laying a porous isolation film 5, a breathable felt 4 and a vacuum bag film 3 on the surface of the glue overflow hole 12 in sequence, so that the porous isolation film 5, the breathable felt 4 and the vacuum bag film 3 cover each glue overflow hole 12, connecting the vacuum generator 2 to the air compressor 1, placing the base of the vacuum generator 2 above the breathable felt 4, so that the vacuum generator 2 is connected to the chamber formed between the breathable felt 4 and the vacuum bag film 3, and is used to provide high-pressure compressed air to the vacuum generator 2 through the air compressor 1, and the vacuum generator 2 forms a vacuum at the outlet through the high-speed flow of compressed air or gas. Then, a vacuum bag is made, and the edge of the vacuum bag film is sealed and connected to the surface of the foam sandwich structure through the first sealing tape 6; a second sealing tape 7 is used to make a fence around each glue injection hole 11, and the fence surrounds the glue injection hole 11 to form a number of glue storage pools.

[0032] Preferably, in this embodiment, the glue is an epoxy resin glue 8, and the epoxy resin glue 8 is prepared by 650 low molecular weight polyamide resin and WSR6101 bisphenol A epoxy resin in a mass ratio of 1:1.

[0033] In order to further improve the repair effect of glue injection, in some embodiments, when injecting glue, a hot air gun is used to assist in heating the repair area, improve the fluidity of the glue, accelerate the curing speed, and ensure that the glue can better penetrate into the place that needs to be repaired; during specific operations, hold the hot air gun so that an angle less than 90° is formed between the hot air gun and the damaged skin 9. When using the hot air gun, maintain a certain distance to avoid direct contact with the material surface. The air outlet of the hot air gun is 5cm-15cm away from the skin, and the air outlet temperature of the hot air gun is 55℃-70℃.

[0034] Preferably, in this embodiment, please refer to Figures 4 to 7 Step S5 includes: after glue overflows from each glue overflow hole 12, the vacuum bag film 3, the breathable felt 4 and the porous isolation film 5 are removed in sequence, the glue overflowing from the skin 9 is wiped off with ethyl acetate, the surface of the skin 9 in the repair area is covered with a non-porous separation film 13, and the non-porous separation film 13 is fixed with a transparent tape 14, and then a sandbag 15 is placed above the repair area, and the repair area is pressed by the weight of the sandbag 15, and the foam sandwich structure is placed in an environment of 25℃-30℃ for 72 hours until the glue is cured.

[0035] Furthermore, in some embodiments, after step S5, step S6 is also included: after the glue is solidified, the transparent tape 14 is torn off. At this time, it is necessary to ensure that the glue has been sufficiently hardened to avoid damaging the surface when tearing off the transparent tape 14. Subsequently, the glue overflow hole 12 and the glue injection hole 11 are sealed with epoxy resin to restore the integrity and aesthetics of the structure.

[0036] Furthermore, in some embodiments, after step S6, step S7 is further included: inspecting the repaired area by nondestructive testing. After repairing the foam sandwich structure, in order to ensure that the quality of the repaired area meets the standards, a variety of nondestructive testing technologies can be used for evaluation without destroying or affecting the performance of the inspected object.

[0037] Among them, non-destructive testing methods can be ultrasonic testing, radiographic testing or visual testing. Ultrasonic testing analyzes the internal defects of the material by emitting ultrasonic waves to the material based on the signal of the reflected wave. Radiographic testing (RT) uses X-rays or Y-rays to penetrate the material and display the internal defects of the material through film or digital imaging system. Visual testing (VT) observes the repair area with the naked eye or with the help of optical instruments. When checking whether there are internal defects in the repair area, ultrasonic testing (UT) or radiographic testing (RT) is preferred.

[0038] The present invention also provides a more specific embodiment, please refer to Figures 1 to 8 , used to illustrate the above steps S1-S7, specifically including: Step 1: Draw the damage boundary: Use tapping inspection, acoustic vibration, etc. to determine the degree of damage in the debonding area, and use a marker to draw the damage boundary.

[0039] Step 2, drilling glue injection holes 11 and glue overflow holes 12: Drill several 1.5mm Ф glue overflow holes 12 and several 2mm Ф glue injection holes 11 in a staggered arrangement in the center and periphery of the debonding area. The glue injection holes 11 are located at the edge of the defect. The distance between the glue injection holes 11 and the glue overflow holes 12 is about 10mm-15mm, and the drilled holes are connected to the debonding area.

[0040] Step 3, make vacuum bag and glue storage pool: lay a layer of porous isolation film 5, breathable felt 4 and vacuum bag film 3 on the surface of the glue overflow hole 12, connect the vacuum generator 2 to the air compressor 1, place the base of the vacuum generator 2 on the breathable felt 4, connect to the inner side of the vacuum bag film 3, and then make a vacuum bag. The porous isolation film 5, breathable felt 4 and vacuum bag film 3 are sealed with a first sealing tape 6 around; use a second sealing tape 7 to make a fence around the glue injection hole 11 to form several small "glue storage pools" to prevent the glue from flowing everywhere.

[0041] Step 4, glue injection: prepare epoxy resin glue 8 with 650 low molecular weight polyamide resin and WSR6101 bisphenol A epoxy resin in a mass ratio of 1:1; stir the glue evenly with a glass rod, fill the "glue storage tank" with glue, and use the vacuum suction of the vacuum generator 2 to make the glue in the "glue storage tank" flow through the glue injection hole 11 along the gap at the debonding point to the glue overflow hole 12, until the glue overflows from the glue overflow hole 12 onto the breathable felt 4; at the same time, use a hot air gun to assist in heating the repair area to promote the diffusion of the glue; hold the hot air gun during operation so that the angle between the hot air gun and the damaged skin 9 is about 30°, the air outlet of the hot air gun is about 5 cm away from the skin 9, and the temperature of the hot air gun is adjusted to about 60°C.

[0042] Step 5, curing: after glue overflows from the overflow hole 12, remove the vacuum bag film 3, the breathable felt 4 and the porous isolation film 5, use ethyl acetate to wipe off the glue overflowing from the skin 9, cover the surface of the skin 9 in the repair area with a layer of non-porous separation film 13, fix it with transparent tape 14, place a 5kg sandbag 15 above the repair area, use the sandbag 15's own gravity to press the repair area, and then place it in an environment of 25℃-30℃ for 72 hours until the glue is cured.

[0043] Step 6: Sealing: After the glue is solidified, tear off the transparent tape 14 and seal the glue overflow hole 12 and the glue injection hole 11 with SY-49 (Q / 6S 3001) epoxy resin.

[0044] Step 7: Quality inspection: Use non-destructive testing to inspect the repaired area to ensure that there are no defects such as debonding between the skin 9 and the core layer.

[0045] In the description of the present application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise expressly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0046] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0047] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for repairing a foam sandwich structure by injection molding, characterized in that: include: S1: providing a foam sandwich structure, and determining a debonding area of ​​the foam sandwich structure; S2: drilling a plurality of glue overflow holes in the debonding area, and drilling a plurality of glue injection holes at the edge of the debonding area, wherein the glue injection holes are connected to the debonding part of the foam sandwich structure; S3: sequentially arranging a breathable layer and a vacuum layer covering a plurality of overflow holes on the degumming area, connecting a vacuum device to a chamber inside the vacuum layer that is connected to the overflow holes, arranging a fence around the injection holes outside the injection holes, and forming a glue storage pool connected to the injection holes inside the fence; S4: preparing glue liquid, filling the glue storage tank with glue liquid, and using the vacuum suction of the vacuum device to make the glue liquid in the glue storage tank flow through the glue injection hole along the gap at the debonding point to the glue overflow hole, until the glue liquid overflows from the glue overflow hole; S5: Seal and press the repair area until the glue cures.

2. The method for repairing a foam sandwich structure by injecting glue according to claim 1, characterized in that: Step S1 includes: Use percussion inspection or sonication to determine the extent of damage in the debonded area and use a marker to mark the damage boundary.

3. The method for repairing a foam sandwich structure by injecting glue according to claim 1, characterized in that: The glue injection holes and the glue overflow holes are arranged in a staggered manner, the diameter of the glue injection holes is 2 mm, the diameter of the glue overflow holes is 1.5 mm, and the hole spacing between each of the glue injection holes and each of the glue overflow holes is 10 mm-15 mm.

4. The method for repairing a foam sandwich structure by injecting glue according to claim 1, characterized in that: The breathable layer includes breathable felt and a porous isolation membrane, the vacuum layer includes a vacuum bag film, and the edge of the vacuum bag film is sealed and connected to the surface of the foam sandwich structure through a first sealing tape; the enclosure is formed by a second sealing tape arranged around the injection hole; the vacuum device includes a vacuum generator and an air compressor.

5. The method for repairing foam sandwich structure by injection of glue according to claim 4, characterized in that: Step S3 includes: On the surface of the glue overflow hole, a porous isolation film, a breathable felt and a vacuum bag film are laid in sequence, so that the porous isolation film, the breathable felt and the vacuum bag film cover each glue overflow hole, the vacuum generator is connected to the air compressor, and the vacuum generator base is placed on the breathable felt, so that the vacuum generator is connected to the chamber formed between the breathable felt and the vacuum bag film, and then a vacuum bag is made, and the edge of the vacuum bag film is sealed and connected to the surface of the foam sandwich structure by a first sealing tape; a second sealing tape is used to make enclosures around each glue injection hole, and the enclosures surround the glue injection holes to form a number of glue storage pools.

6. The method for repairing a foam sandwich structure by injecting glue according to claim 1, characterized in that: The glue is an epoxy resin glue, which is prepared by mixing 650 low molecular weight polyamide resin and WSR6101 bisphenol A epoxy resin in a mass ratio of 1:

1.

7. The method for repairing a foam sandwich structure by injecting glue according to claim 1, characterized in that: When injecting glue, use a hot air gun to assist in heating the repair area; hold the hot air gun during operation so that an angle of less than 90° is formed between the hot air gun and the damaged skin. The air outlet of the hot air gun is 5cm-15cm away from the skin, and the air outlet temperature of the hot air gun is 55℃-70℃.

8. The method for repairing a foam sandwich structure by injecting glue according to claim 1, characterized in that: Step S5 includes: After glue overflows from the glue overflow hole, remove the breathable layer and the vacuum layer, use ethyl acetate to wipe off the glue overflowing on the skin, cover the skin surface in the repair area with a non-porous separation film, and fix the non-porous separation film with transparent tape, then place sandbags above the repair area, use the sandbags' own gravity to press the repair area, and place the foam sandwich structure in an environment of 25℃-30℃ for more than 72 hours until the glue solidifies.

9. The method for repairing a foam sandwich structure by injecting glue according to claim 1, characterized in that: After step S5, the method further includes step S6: After the glue is solidified, tear off the transparent tape and seal the glue overflow holes and injection holes with epoxy resin.

10. The method for repairing a foam sandwich structure by injecting glue according to claim 9, characterized in that: After step S6, the method further includes step S7: The repaired area is inspected using non-destructive testing methods.

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