Vacuum bag-free composite material repair system and method

Abstract

The present invention relates to vacuum bag-free composite repair systems and methods. Methods and systems for repairing composite parts without using vacuum bagging are described. The system described herein includes a composite repair structure having a repair laminate and a film sealant. The film sealant covers the repair laminate to prevent the ingress of air and other volatiles when the composite repair structure is bonded to the composite material to be repaired. Because the film sealant prevents the ingress of air and other volatiles, the composite repair structure can be bonded to the structure to be repaired without using a vacuum bag. Therefore, a vehicle component can be repaired without disassembly from the vehicle.

Description

Technical Field

[0001] The invention relates to a vacuum bag-free composite material repair system and method. Background Art

[0002] Current composite repair processes require vacuum bags to repair composite laminates. However, the use of vacuum bags complicates the repair process. For example, in certain processes, the vacuum bag must be checked for vacuum leaks and maintained at a minimum vacuum level to ensure that the vacuum bag provides an adequate seal. These vacuum requirements are problematic because they cannot be met in many repair situations. For example, vacuum bags used to repair composite propulsion structures (such as sound inlets and reverse thrust inner walls) that have sound attenuation features (such as perforated composite panels and slotted honeycomb cores) are often difficult or impossible to meet these requirements. Such perforated or slotted features are difficult or impossible to seal and create a large number of possible leak paths.

[0003] To overcome this problem, repairs to these propulsion structures require that they be removed from the vehicle and disassembled so that they can be completely enclosed in giant vacuum bags. The number of man-hours required to disassemble and then reassemble the parts adds time and complexity to the repair process and requires specialized equipment and facilities, increasing repair costs and vehicle downtime. Summary of the invention

[0004] Methods and systems for repairing composite parts without the use of vacuum bags are described. The systems described herein allow for the repair of structures, such as vehicle structures, using composite repair patches known as composite repair structures. The composite repair structure can be bonded to the vehicle structure by applying heat and positive pressure. To prevent the ingress of air and volatiles during bonding of the composite repair structure to the vehicle structure, the composite repair structure includes a film sealant disposed over the repair laminate. Because the film sealant prevents the ingress of air and other volatiles, the composite repair structure can be cured and bonded to the structure to be repaired without the use of vacuum bags.

[0005] Illustrative, non-exclusive examples of inventive features according to the present disclosure are described in the following enumerated paragraphs:

[0006] A1. A method 400, the method 400 comprising:

[0007] forming (step 420) a composite repair structure 200, wherein the composite repair structure 200 includes a repair laminate 206, and wherein forming (step 420) the composite repair structure 200 includes applying (step 404) a membrane sealant 202 to a first surface 204A of the repair laminate 206;

[0008] coupling (step 410) the composite repair structure 200 to the vehicle structure 120; and

[0009] The composite repair structure 200 is cured and / or bonded (step 422 ) to the vehicle structure 120 by providing (step 416 ) positive pressure 320 to the composite repair structure 200 coupled to the vehicle structure 120 , wherein the membrane sealant 202 prevents air from intruding into the repair laminate 206 during the curing and / or bonding of the composite repair structure 200 to the vehicle structure 120 .

[0010] A2. The method 400 of paragraph A1, wherein curing and / or bonding (step 422 ) the composite repair structure 200 to the vehicle structure 120 further comprises providing (step 414 ) heat to the composite repair structure 200 coupled to the vehicle structure 120 .

[0011] A3. The method 400 of any of paragraphs A1 to A2, wherein the film sealant 202 is also applied (step 404) to a second surface 204B of the repair laminate 206 opposite the first surface 204A.

[0012] A4. The method 400 of any of paragraphs A1 to A3, wherein the positive pressure 320 is provided (step 416) in the absence of a vacuum.

[0013] A5. The method 400 of any one of paragraphs A1 to A4, wherein forming 420 the composite repair structure 200 further comprises:

[0014] applying (step 405) heat to the composite repair structure 200 to degas the composite repair structure 200;

[0015] placing the composite repair structure 200 within the chamber 500, wherein the chamber 500 is configured to minimize compaction on the composite repair structure 200 when a vacuum is present within the chamber 500; and

[0016] A vacuum is provided (step 406 ) within chamber 500 .

[0017] A6. The method 400 of any of paragraphs A1 to A5, wherein repair laminate 206 includes resin 208 , and wherein film sealant 202 has a higher minimum viscosity temperature than resin 208 .

[0018] A7. The method 400 of any of paragraphs A1 to A6, wherein forming (step 420 ) the composite repair structure 200 further comprises stacking (step 402 ) a plurality of repair laminate materials 206 .

[0019] A8. The method 400 of any of paragraphs A1 to A7, wherein curing and / or bonding (step 422) the composite repair structure 200 further comprises preparing (step 412) the composite repair structure 200 after coupling (step 410) the composite repair structure 200 to the vehicle structure 120, wherein preparing (step 412) the composite repair structure 200 comprises:

[0020] applying a release film 312 to a portion of the composite repair structure 200; and

[0021] A compliant layer 314 is applied to the portion of the composite repair structure 200 .

[0022] A9. The method 400 of any of paragraphs A1 to A8, wherein coupling the composite repair structure 200 to the vehicle structure 120 includes:

[0023] applying film adhesive 310 to a portion 322 of vehicle structure 120 ;

[0024] coupling the composite repair structure 200 to the film adhesive 310;

[0025] After composite repair structure 200 has been coupled to film adhesive 310 to position composite repair structure 200, placing compaction bag 318 over composite repair structure 200; and

[0026] The compaction bag 318 is removed.

[0027] Alternatively, the compaction bag 318 is deflated to atmosphere to remove the vacuum from the repair laminate 206 , and positive pressure and / or heat is applied through or over the compaction bag 318 .

[0028] A10. The method 400 of any of paragraphs A1 to A9, wherein composite repair structure 200 is coupled to vehicle structure 120 when coupling vehicle structure 120 to vehicle 100 .

[0029] A11. A composite repair structure 200, the composite repair structure 200 comprising:

[0030] repairing laminate 206; and

[0031] and a film sealant 202 disposed on the first surface 204A of the repair laminate 206, wherein the composite repair structure 200 is configured to be cured and / or bonded to the vehicle structure 120 by a positive pressure 320 applied to the composite repair structure 200 when the composite repair structure 200 is coupled to the vehicle structure 120, and wherein the film sealant 202 prevents air from intruding into the repair laminate 206 during the curing and / or bonding of the composite repair structure 200 to the vehicle structure 120.

[0032] A12. The composite repair structure 200 of paragraph A11, wherein the membrane sealant 202 is further disposed on a second surface 204B of the repair laminate 206 opposite the first surface 204A.

[0033] A13. The composite repair structure 200 of any of paragraphs A11 to A12, wherein the repair laminate 206 includes a resin 208 , and wherein the film sealant 202 has a higher minimum viscosity temperature than the resin 208 .

[0034] A14. A method 420 of forming the composite repair structure 200 described in any one of paragraphs A11 to A13, the method comprising:

[0035] stacking 402 repair laminate material 206;

[0036] applying 405 heat to the repair laminate material 206 to degas the repair laminate material 206; and

[0037] The film sealant 202 is applied 404 to the first surface 204A.

[0038] A15. The method 420 of paragraph A14, wherein applying heat 405 to the repair laminate 206 to degas the repair laminate 206 comprises:

[0039] reducing the viscosity of the resin 208 of the repair laminate 206; and

[0040] The fibers of the repair laminate 206 are covered with the resin 208 .

[0041] A16. A device, comprising:

[0042] vehicle structure 120; and

[0043] A composite repair structure 200, the composite repair structure 200 being coupled to a portion of the vehicle structure 120, the composite repair structure 200 comprising:

[0044] repairing laminate 206; and

[0045] A film sealant 202 is disposed on a first surface 204A of the repair laminate 206 , wherein the film sealant 202 is configured to prevent air intrusion into the repair laminate 206 during curing and / or bonding of the composite repair structure 200 to the vehicle structure 120 .

[0046] A17. The apparatus of paragraph A16, wherein the membrane sealant 202 is also disposed on a second surface 204B of the repair laminate 206 opposite the first surface 204A.

[0047] A18. The apparatus of any of paragraphs A16 to A17, wherein the repair laminate 206 includes a resin 208 , and wherein the membrane sealant 202 has a higher minimum viscosity temperature than the resin 208 .

[0048] A19. The apparatus of any of paragraphs A16 to A18, further comprising:

[0049] a release film 312 disposed on the portion of the vehicle structure 120;

[0050] a compliant layer 314 disposed on the portion of the vehicle structure 120 ; and

[0051] A load, pneumatic bladder, or actuator coupled to the composite repair structure 200 to apply positive pressure 320 on the composite repair structure 200 .

[0052] A20. The apparatus of any of paragraphs A16 to A19, wherein the vehicle structure 120 is a propeller, a fuselage, or a wing.

[0053] These and other examples are further described below with reference to the figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The present disclosure may be best understood by referring to the following description taken in conjunction with the accompanying drawings which illustrate various examples.

[0055] Figure 1 A vehicle having a composite structure according to some examples is illustrated.

[0056] Figure 2 Illustrated are cross-sectional views of composite repair structures according to some examples.

[0057] Figure 3AThe use of some examples is illustrated Figure 2 A cross-sectional view of the steps in the composite repair technique of a composite repair structure.

[0058] Figure 3B The use of some examples is illustrated Figure 3A A cross-sectional view of another step in the composite repair technique of a composite repair structure.

[0059] Figure 4 is a process flow diagram corresponding to a composite repair method according to some examples.

[0060] Figure 5A A cross-sectional view of a double vacuum debulk chamber is illustrated according to some examples.

[0061] Figure 5B Illustrated according to some examples Figure 5A Cross-sectional view of the lower bag of the double vacuum hold-down chamber.

[0062] Fig. 6A A flow chart illustrating an example of an aircraft production and service method according to some examples is shown.

[0063] Figure 6B A block diagram illustrating an example of a vehicle according to some examples is illustrated. DETAILED DESCRIPTION

[0064] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the concepts proposed. The concepts proposed may be practiced without some or all of these specific details. In other cases, well-known processing operations are not described in detail to avoid unnecessarily obscuring the concepts described. Although some concepts will be described using specific examples, it will be understood that these examples are not intended to be limiting.

[0065] introduce

[0066] Currently, the technique for repairing certain composite vehicle components with noise attenuation features, such as a nacelle or thruster inlet, is to remove the component from the vehicle and disassemble the component before performing the repair using a vacuum bag. Even a minor repair requires the removal of these very large and expensive parts from the vehicle and the placement of these parts in a vacuum bag. In addition, the disassembly (fastener removal, separation of surface-sealed components, removal of rivets, and other such disassembly steps) and subsequent handling of such large, cumbersome structures greatly increases the risk of accidental damage to the parts. As a result, such techniques require a great deal of time and effort to perform and increase the complexity and expense of the repair process.

[0067] Figure 1 An example of a vehicle having such a structure is shown. Figure 1 A vehicle having a composite structure according to some examples is illustrated. Figure 1 The vehicle 100 is illustrated as being a fixed-wing aircraft. In other examples, the systems and techniques described herein can be used to repair composite materials and structures of other types of vehicles, such as other types of aircraft (e.g., helicopters, spacecraft, rockets, and other aircraft), automobiles, ships, submarines, and other such vehicles.

[0068] The vehicle 100 includes a plurality of vehicle structures 120. In various examples, the vehicle structures 120 may be different portions of the vehicle 100. For example, Figure 1 In the aircraft shown, the vehicle structure 120 can be a fuselage, a wing (e.g., a fixed portion of a wing or a flap or other movable portion), an aircraft propeller (e.g., a nacelle or inlet of an aircraft propeller), an empennage, or other structure of the aircraft. Various examples of the vehicle structure 120 can be made of composite materials, such as fiberglass, carbon fiber, and one or more of other such composite materials.

[0069] Example of a structure for vacuum bag free composite repair

[0070] Figure 2 Illustrated are cross-sectional views of composite repair structures according to some examples. Figure 2 A composite repair structure 200 is illustrated for repairing (e.g., patching) a composite structure such as the vehicle structure 120 described herein. In some examples, the composite repair structure 200 is used to repair a composite vehicle structure, such as by being coupled or bonded to the composite vehicle structure. For example, bonding the composite repair structure 200 to such a vehicle structure is accomplished by applying positive pressure and heat and without using vacuum bagging. The composite repair structure 200 includes film sealants 202A and 202B and repair laminates 206A to 206C.

[0071] The repair laminate materials 206A to 206C include composite layers, such as carbon fiber layers, glass fiber layers, In some examples, layers of repair laminate material are stacked on top of each other to form a core repair structure. Figure 2 The illustrated example illustrates a composite repair structure 200 including three layers of repair laminate material 206A-206C, but other examples may include any number of layers of repair laminate material.

[0072] The repair laminates 206A to 206C are combined with a resin 208 or another type of polymer. The resin 208 penetrates the fibers of the repair laminates 206A to 206C to cure the repair laminates 206A to 206C. In some examples, the repair laminates 206A to 206C are pre-impregnated (prepreg) composite materials, for example, with the resin 208 pre-impregnated in the repair laminates 206A to 206C. The prepreg is heated during production to liquefy the resin 208, thereby allowing the resin 208 to penetrate the fibers of the repair laminates 206A to 206C and displace any air in the fibers. Since any air retained in the repair laminates 206A to 206C will weaken the composite repair structure 200, the repair laminates 206A to 206C are fully infiltrated by the resin 208 to fully displace any air during the production process. Completely displacing the air maximizes the strength of the composite repair structure 200.

[0073] The repair structure is typically heated to bond the repair structure to the vehicle structure. As the repair structure is heated, the resin will return to a liquid state. In conventional repair processes, containing the vehicle structure and the repair structure within a vacuum bag prevents subsequent air intrusion while the resin is in a liquid state. However, without vacuum bagging, air and other volatiles will intrude into the resin and thereby into the repair laminate during the conventional repair process, causing loosening and weakening of the structure.

[0074] The film sealants 202A and 202B are disposed on the surfaces of the repair laminates 206A-206C. Thus, for example, the film sealant 202A is disposed on a first surface of the repair laminates 206A-206C, and the film sealant 202B is disposed on a second surface of the repair laminates 206A-206C opposite the first surface. In various examples, the film sealants are disposed on various portions of the repair laminates 206A-206C or on all exterior surfaces of the repair laminates 206A-206C. The film sealants (including the film sealants 202A and 202B) prevent air from intruding into the repair laminates during bonding of the composite repair structure 200 to the vehicle structure 120. Because the film sealants prevent air from intruding into the repair laminates, the composite repair structure 200 can be bonded to the vehicle structure without using a vacuum or vacuum bag.

[0075] In some examples, to prevent the ingress of air and other volatiles, the film sealants 202A and 202B have a higher minimum viscosity temperature than the resin 208. Thus, when the resin is most susceptible to air ingress (e.g., when the resin is at its lowest viscosity, such as when the composite repair structure 200 is heated to bond the composite repair structure 200 to the vehicle structure 120), the film sealants 202A and 202B act as an effective air barrier. During the repair process, as the temperature rises due to heating, the resin 208 then gels (e.g., the viscosity of the resin 208 increases) to a point where air no longer or only minimally penetrates the resin 208 and / or the repair laminates 206A to 206C. At this elevated temperature, the viscosity of the film sealants 202A and 202B can then be at its minimum level. The film sealants 202A and 202B can thus mix (comingle) with the resin 208 and any adhesive on the vehicle structure, thereby creating a strong and durable bond.

[0076] As such, film sealants 202A and 202B, as well as any other film sealants disposed on the surface of composite repair structure 200 , allow composite repair structure 200 to be bonded to vehicle structure 120 without the use of a vacuum bag, while still preventing the intrusion of air and volatiles into resin 208 .

[0077] The various steps of the vacuum bag-free repair technique are now illustrated herein. Figure 3A The use of some examples is illustrated Figure 2 A cross-sectional view of the steps in the composite repair technique of a composite repair structure. Figure 3A Assembly 300A is illustrated, detailing the steps when composite repair structure 200 is coupled to vehicle structure 120. Assembly 300A illustrates the steps of positioning composite repair structure 200 on vehicle structure 120 (eg, in preparation for bonding during a patch repair).

[0078] Thus, composite repair structure 200 is placed on portion 322 of vehicle structure 120. In some examples, portion 322 is a portion of vehicle structure 120 that requires repair. Film adhesive 310 is placed on portion 322. Film adhesive 310 is placed between portion 322 and composite repair structure 200. Film adhesive 310 facilitates bonding of composite repair structure 200 to portion 322.

[0079] The compaction bag 318 may optionally be placed over and / or contain the composite repair structure 200 to provide a vacuum to properly position the composite repair structure 200 over the portion 322. In some examples, the compaction bag 318 does not meet the typical vacuum requirements of vacuum bag applications. Alternatively, the compaction bag 318 may be a temporary compaction bag for positioning the composite repair structure 200. In some examples, a release film 312 is disposed between the composite repair structure 200 and the compaction bag 318 to facilitate the release of the compaction bag 318 from the composite repair structure 200 once the composite repair structure 200 is positioned. After use, the compaction bag 318 may be discarded. Alternatively, in some examples, the compaction bag 318 is deflated to atmosphere to remove the vacuum from the repair laminate 206, and positive pressure and / or heat is applied through or over the compaction bag 318.

[0080] Figure 3B The use of some examples is illustrated Figure 3A A cross-sectional view of another step in the composite repair technique of a composite repair structure. Figure 3B Assembly 300B is illustrated, detailing the steps when the composite repair structure 200 is joined to the vehicle structure 120 .

[0081] In some examples, after the composite repair structure 200 is coupled to the vehicle structure 120, a release film 312 is disposed over the composite repair structure 200. A compliant layer 314 is then applied over the release film 312. In some such examples, the compliant layer is a thin (e.g., 0.5 inches or less), low durometer, thermally conductive material that will conform to the shape of the repair (e.g., the composite repair structure 200) to provide better load transfer to the composite repair structure 200.

[0082] A heating blanket 316 is disposed over the compliant layer 314. The heating blanket 316 is configured to provide heat to the composite repair structure 200 and / or the portion 322 to allow the composite repair structure 200 to be bonded to the portion 322. Additionally, in some examples, a layer of silicone rubber foam (e.g., between 0.25 inches and 2 inches thick) is placed over the heating blanket 316 to thermally isolate the repair from items that provide positive pressure 320 to the repair.

[0083] The heating blanket 316 provides heat to increase the temperature of the composite repair structure 200 and / or the vehicle structure 120. Certain examples of the heating blanket 316 are configured to heat the composite repair structure 200 to various temperatures. Thus, for such examples, the heating blanket 316 increases the temperature of the composite repair structure 200 over a period of time by continuously providing heat to the composite repair structure 200. In this way, the composite repair structure 200 is heated for a period of time. For example, the composite repair structure 200 is first heated to a first temperature, whereby the resin 208 is more viscous or liquid to aid in bonding with the vehicle structure 120. As the temperature increases, the resin 208 begins to harden, while the film sealants 202A and 202B become more viscous or liquid. The reduced viscosity of the film sealants 202A and 202B allows the film sealants 202A and 202B to mix with the resin 208 and any adhesives of the vehicle structure 120, thereby creating a strong and durable bond.

[0084] In some examples, positive pressure 320 is also provided to create a strong and durable bond. As described herein, positive pressure refers to any type of pressure applied. For example, positive pressure includes pressure provided by a load (e.g., a shot or sandbag), a machine (e.g., an actuator, a fixture, a press, or other machine), a pneumatic airbag, or pressure is provided by other techniques. In some examples, positive pressure 320 is any amount of pressure, including pressure between 1 pound per square inch and 10 pounds per square inch (psi) applied to the composite repair structure 200. Positive pressure 320 further bonds the composite repair structure 200 to the vehicle structure 120 by allowing the resin 208, the membrane sealant 202A and / or 202B, and / or any adhesive of the vehicle structure 120 to mix and / or intermix to form a strong bond.

[0085] Examples of methods used for vacuum bag free composite repair

[0086] Figure 4 is a process flow chart corresponding to a composite repair method according to some examples. Figure 4 The various operations of method 400 are described in detail. Steps 402 to 406 describe the formation 420 of the composite repair structure 200, while steps 408 to 418 describe the repair of a vehicle structure using the composite repair structure.

[0087] In step 402, the repair laminate 206 is stacked. In some examples, the repair laminate 206 includes a plurality of composite layers (e.g., carbon fiber composite layers). The layers stacked in step 402 form the repair laminate 206. In step 404, the film sealant 202 is applied to the outer surface of the repair laminate 206. The film sealant 202 prevents air and volatiles from invading the resin 208 and / or the repair laminate 206 during vacuum bag-free bonding to the vehicle structure 120.

[0088] In step 406, the composite repair structure 200 is placed in a vacuum chamber and a vacuum is applied to the composite repair structure 200. Such a vacuum may be applied, for example, in a double vacuum hold-down chamber (e.g., Figure 5A and Figure 5B ). Dual vacuum compaction allows for the removal of volatiles from the repair laminate 206 without the use of an autoclave. Dual vacuum compaction allows for the application of heat and vacuum to the composite repair structure 200 without subjecting the composite repair structure 200 to vacuum compaction (e.g., from atmospheric pressure acting on a vacuum bag).

[0089] In step 405, heat is applied during one or more of steps 402, 404, and 406. Heating the membrane sealant 202, the repair laminate 206, the resin 208, and / or another portion of the composite repair structure 200 to various temperatures reduces the viscosity of the resin and / or sealant and / or partially cures the resin and / or sealant to partially cure the composite repair structure 200. In some examples, heat is applied during both steps 402 and 404 to, for example, allow entrapped air and gas to vent or degas the repair laminate 206, and potentially cure the repair laminate 206 in step 402 and the membrane sealant 202 in step 404, respectively. In other examples, heat is applied during step 406 to first reduce viscosity to allow venting of air from the repair laminate 206, and then partially cure both the repair laminate 206 and the membrane sealant 202 simultaneously.

[0090] Thus, after steps 402, 404, 405, and / or 406, the composite repair structure 200 is formed in a compliant intermediate state. Such an intermediate state allows the composite repair structure 200 to be coupled to and conform to a surface of a vehicle structure. Once coupled to the vehicle structure, heat and positive pressure are applied to fully cure the composite repair structure 200 into a solid state, as described herein.

[0091] Thus, after the composite repair structure 200 has been formed, the composite repair structure 200 is used to repair a vehicle structure in steps 408 through 418. In step 408, the surface of a portion of the vehicle structure 120 to be repaired is prepared. The preparation includes, for example, applying the film adhesive 310 over the surface of the vehicle structure 120, cleaning and sanding the surface of the vehicle structure 120 (e.g., to promote better adhesion), and / or other such preparatory activities.

[0092] According to the techniques described herein, after the vehicle structure 120 has been prepared in step 408, the composite repair structure 200 is coupled to the vehicle structure 120 in step 410. Thus, for example, the composite repair structure 200 is positioned over a portion of the vehicle structure 120 to be repaired. In some examples, a compaction bag 318 is also disposed over the composite repair structure 200 to position the composite repair structure 200 over the appropriate portion of the vehicle structure 120.

[0093] Thus, the composite repair structure 200 is appropriately positioned over the vehicle structure 120. Then, in steps 412 to 416, the composite repair structure 200 is then cured and / or bonded 422 to the vehicle structure 120 or a portion thereof. Curing and / or bonding 422 includes, for example, preparing the composite repair structure 200 in step 412. Preparing the composite repair structure 200 includes, for example, applying a release film 312 and / or disposing a compliant layer 314 on the composite repair structure 200.

[0094] Heat and positive pressure are then applied in steps 414 and 416, respectively, to cure and / or bond 422 the composite repair structure 200 to the vehicle structure 120. In some examples, the composite repair structure 200 and the vehicle structure 120 are co-bonded. That is, the composite repair structure 200 (e.g., the repair laminate 206) is cured while being bonded to the vehicle structure 120 (which is the second cured laminate).

[0095] In step 416, positive pressure is applied by techniques described herein (e.g., mechanically, by a load, by a force applied to a surface of the composite repair structure 200, or other techniques). In step 414, heat is applied to the composite repair structure 200 and / or the vehicle structure 120, such as by heat from a heating blanket 316, from a heat lamp, from a heat gun, or from another source. The composite repair structure 200 is thus bonded to the vehicle structure 120. The repair is then completed in step 418 by, for example, surface treatment (e.g., sanding) and finishing (e.g., painting) of the repair.

[0096] Manufacturing chamber for composite repair structures

[0097] As described herein, composite repair structure 200 is at least partially formed in a dual vacuum hold-down chamber. Figure 5A A cross-sectional view of a dual vacuum compaction chamber according to some examples is illustrated. Dual vacuum compaction allows for the removal of volatiles from the repair laminate 206 by applying heat and vacuum while forming the composite repair structure 200 without subjecting the composite repair structure 200 to vacuum compaction, after the repair laminate 206 has been stacked, without the use of an autoclave.

[0098] Figure 5A The double vacuum hold-down chamber 500 shown in FIG. 5 includes an upper bagging film 502, a venting cloth 504, a hardback 506, a vacuum probe 508, a ventilator 510, and a lower bag 512. The composite repair structure 200 is arranged in the lower bag 512 during its formation. The upper bagging film 502 is a vacuum bag and is configured to contain a vacuum. The vacuum probe 508 allows the vacuum in the upper bagging film 502 to be adjusted.

[0099] The hard encapsulation 506 is disposed above the lower bag 512 and, in some examples, is a rigid or semi-rigid structure. In some examples, when a vacuum exists within the upper bagging film 502, the hard encapsulation 506 prevents the upper bagging film 502 from exerting a force on the lower bag 512. When a vacuum is generated within the upper bagging film 502, the hard encapsulation 506 prevents the compressive force from the vacuum within the upper bagging film 502 from being applied to the composite repair structure 200 (contained within the lower bag 512). Thus, the hard encapsulation 506 allows the composite repair structure 200 to be formed within the vacuum, but is not subjected to the compressive force from the vacuum.

[0100] Figure 5B Illustrated according to some examples Figure 5A Cross-sectional view of the lower bag of the double vacuum hold-down chamber. Figure 5B A lower bag 512 is further illustrated. Figure 5B The lower bag 512 shown in the figure includes a lower bagging film 514, a breather 516, non-porous release films 518 and 524, a bleeder 520, a porous or perforated release film or fabric 522, a thermally conductive sheet 526, a heating element 528, a breather 530, and an electrical circuit 532. In the example shown, the composite repair structure 200 is arranged within the layer of porous or perforated release film or fabric 522.

[0101] The circuit 532 provides electrical power to the heating element 528. The heating element 528 is, for example, a heating blanket. The heating element 528 generates heat from the electrical power provided. The heat is then used to reduce the viscosity of the resin of the composite repair structure 200. In some examples, preventing air compaction when forming the repair laminate 206 (e.g., when a vacuum is generated and heat is provided by the heating element 528) allows gases and other volatiles to be extracted from the fibers of the repair laminate 206. The reduced viscosity of the resin 208 allows the resin 208 to flow into the volume previously occupied by the gases and volatiles. In some examples, the resin 208 can then occupy most or all of the space around the fibers of the repair laminate 206.

[0102] In some examples, after the gases and volatiles are extracted, the hard encapsulation 506 is vented to atmosphere. Atmospheric pressure can then apply a compressive force on the lower bag 512 and, therefore, on the composite repair structure 200 to form the composite repair structure 200 into a final shape. By applying a compressive force only after the gases and volatiles are extracted, the techniques described herein allow the trapped gases and volatiles to be vented, thereby avoiding the trapping of such gases and volatiles within the composite repair structure 200. This technique produces a stronger composite repair structure 200. Thereafter, the composite repair structure 200 is removed from the double vacuum hold-down chamber 500 and is ready to be bonded to a vehicle structure.

[0103] Transportation Examples

[0104] Although the above disclosed systems, devices, and methods have been described with reference to the aircraft and aerospace industries, it should be understood that the examples disclosed herein are also applicable to other contexts, such as automotive, railroad, and other mechanical and vehicle contexts. Fig. 6A Aircraft manufacturing and service method 600 is shown and Figure 6B Examples of the present disclosure are described in the context of a vehicle 100 as shown.

[0105] Fig. 6A A flowchart of an example of a vehicle production and service method according to some examples is illustrated. In some examples, during pre-production, the method 600 includes a vehicle 100 (e.g., Figure 1 604 and material procurement 606. During production, component and subassembly manufacturing 608 and system integration 610 of the vehicle 100 occurs. Thereafter, the vehicle 100 undergoes certification and delivery 612 in order to be placed into service 614. When serviced by a customer, the vehicle 100 is scheduled for routine maintenance and repair 614 (e.g., modification, reconstruction, refurbishment, etc.).

[0106] In some examples, the various processes of method 600 are performed or carried out by a system integrator, a third party, and / or an operator (e.g., a customer). For the purposes of this description, a system integrator includes any number of aircraft manufacturers and main system subcontractors; a third party includes any number of contractors, subcontractors, and suppliers; and an operator may be an airline, a leasing company, a military entity, a service organization, etc.

[0107] Figure 6B A block diagram illustrating an example of a vehicle according to some examples is shown. Figure 6B As shown, a vehicle 100 (e.g., an aircraft) produced by method 600 includes a fuselage 618 and an interior 622 having a plurality of systems 620. Examples of system 620 include one or more of a propulsion system 624, an electrical system 626, a hydraulic system 628, and an environmental system 630. In various examples, other systems are also included within vehicle 100. Although an aviation example is shown, the principles of the embodiments disclosed herein may be applied to other industries, such as the automotive industry.

[0108] in conclusion

[0109] Although the foregoing concepts have been described in detail for the purpose of clear understanding, it will be apparent that certain changes and modifications may be made within the scope of the appended claims. It should be noted that there are many alternatives to the processes, systems and devices of implementation. Therefore, this example should be considered illustrative rather than restrictive.

Claims

1. A repair method (400), the method (400) comprising: forming (420) a composite repair structure (200), wherein the composite repair structure (200) includes a repair laminate (206), and wherein forming (420) the composite repair structure (200) includes applying a membrane sealant (202) to a first surface (204A) of the repair laminate (206); coupling (410) the composite repair structure (200) to a vehicle structure (120); and curing and / or bonding (422) the composite repair structure (200) to the vehicle structure (120) by providing positive pressure (320) to the composite repair structure (200) coupled to the vehicle structure (120), wherein the film sealant (202) prevents air intrusion into the repair laminate (206) during curing and / or bonding (422) the composite repair structure (200) to the vehicle structure (120); Wherein, the repair laminate material (206) comprises a resin (208), wherein the film sealant (202) has a higher minimum viscosity temperature than the resin (208), wherein the minimum viscosity temperature of the film sealant is the temperature at which the resin is at least partially gelled; Therein, the positive pressure (320) is provided in the absence of a vacuum.

2. The method (400) of claim 1, wherein curing and / or bonding (422) the composite repair structure (200) to the vehicle structure (120) further comprises providing heat to the composite repair structure (200) coupled to the vehicle structure (120).

3. The method (400) according to claim 1, wherein: The film sealant (202) is also applied to a second surface (204B) of the repair laminate (206) opposite the first surface (204A).

4. The method (400) according to claim 1, wherein: Forming (420) the composite repair structure (200) further includes stacking (402) a plurality of repair laminates (206).

5. The method (400) according to claim 1, wherein: Curing and / or bonding (422) the composite repair structure (200) further includes preparing (412) the composite repair structure (200) after coupling (410) the composite repair structure (200) to the vehicle structure (120), wherein preparing (412) the composite repair structure (200) includes: applying a release film (312) to a portion of the composite repair structure (200); and A compliant layer (314) is applied to the portion of the composite repair structure (200).

6. The method (400) of claim 1, wherein: Coupling the composite repair structure (200) to the vehicle structure (120) includes: applying a film adhesive (310) to a portion (322) of the vehicle structure (120); coupling the composite repair structure (200) to the film adhesive (310); After the composite repair structure (200) has been coupled to the film adhesive (310) to position the composite repair structure (200), placing a compaction bag (318) over the composite repair structure (200); and The compaction bag (318) is removed.

7. The method (400) of claim 1, wherein the composite repair structure (200) is coupled to the vehicle structure (120) when coupling the vehicle structure (120) to a vehicle (100).

8. A composite repair structure (200), comprising: Repairing laminates (206); as well as a film sealant (202) disposed on a first surface (204A) of the repair laminate (206), wherein the composite repair structure (200) is configured to be cured and / or bonded to the vehicle structure (120) by positive pressure (320) applied to the composite repair structure (200) when the composite repair structure (200) is coupled to the vehicle structure (120), and wherein the film sealant (202) prevents intrusion of air into the repair laminate (206) during curing and / or bonding of the composite repair structure (200) to the vehicle structure (120); Wherein, the repair laminate material (206) comprises a resin (208), wherein the film sealant (202) has a higher minimum viscosity temperature than the resin (208); wherein the minimum viscosity temperature of the film sealant is the temperature at which the resin is at least partially gelled; Therein, the positive pressure (320) is provided in the absence of a vacuum.

9. The composite repair structure (200) according to claim 8, wherein: The film sealant (202) is also disposed on a second surface (204B) of the repair laminate (206) opposite the first surface (204A).

10. A method of forming the composite repair structure (200) according to claim 8, the method comprising: stacking (402) the repair laminate material (206); applying heat to the repair laminate (206) to degas the repair laminate (206); as well as The film sealant (202) is applied to the first surface (204A).

11. The method according to claim 10, wherein: Applying the heat to the repair laminate (206) to degas the repair laminate (206) includes: reducing the viscosity of the resin (208) of the repair laminate (206); and The fibers of the repair laminate (206) are covered with the resin (208).

12. An apparatus comprising a vehicle structure (120) and a composite repair structure (200) coupled to the vehicle structure (120), wherein: The composite repair structure (200) comprises: repairing laminated materials (206); and a membrane sealant (202) disposed on a first surface (204A) of the repair laminate (206), wherein the membrane sealant (202) is configured to prevent air intrusion into the repair laminate (206) during curing and / or bonding of the composite repair structure (200) to the vehicle structure (120); Wherein, the repair laminate material (206) comprises a resin (208), wherein the film sealant (202) has a higher minimum viscosity temperature than the resin (208); wherein the minimum viscosity temperature of the film sealant is the temperature at which the resin is at least partially gelled; Therein, positive pressure (320) is provided in the absence of a vacuum.

13. The device according to claim 12, wherein: The film sealant (202) is also disposed on a second surface (204B) of the repair laminate (206) opposite the first surface (204A).

14. The device according to claim 12, further comprising: a release film (312) disposed on the portion of the vehicle structure (120); a compliant layer (314) disposed on the portion of the vehicle structure (120); as well as A load is coupled to the composite repair structure (200) to apply a positive pressure (320) to the composite repair structure (200).

15. The apparatus according to claim 12, wherein: The vehicle structure (120) is a propeller, a fuselage or a wing.

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