Systems and methods for curing composite structures

Abstract

To provide a system and a method for curing a composite structure that can eliminate or reduce the need for using an autoclave.SOLUTION: A composite curing system (100) includes a constraining container (102) and an expandable medium (130). The constraining container (102) includes a base (104) and a cover (106) and has an interior volume (114). The constraining container (102) is configured to enclose at least a portion of a composite structure (200). The expandable medium (130) is configured to be disposed within the interior volume (114) between at least a portion of the constraining container (102) and the composite structure (200). The interior volume (114) of the constraining container (102) is selectively variable.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to composite manufacturing, and more particularly to systems and methods for curing composite structures. [Background technology]

[0002] Engineered composite materials are used in many applications, especially when the composites can be manufactured with higher strength, lighter weight, and / or at lower cost than traditional materials. While a variety of composite materials currently exist, the most common are fiber-reinforced composites, such as glass fiber composites and carbon fiber composites. Many composite manufacturing processes involve curing composite structures, which typically occurs at elevated temperatures and pressures. Because autoclaves allow for the application of both temperature and pressure under controlled conditions, industrial autoclaves are often used to cure composites. However, processes requiring autoclaves can create bottlenecks in the manufacturing process due to throughput limitations on the autoclave's capacity and the need to transport raw materials and uncured parts to and from the autoclave after curing. Therefore, those skilled in the art continue to conduct research and development in the field of predictive assembly. Summary of the Invention

[0003] Disclosed herein are embodiments of a composite structure curing system, a composite structure curing method, and a composite workpiece. The following non-exhaustive list of embodiments of the presently disclosed subject matter may or may not be recited in the claims.

[0004] In one embodiment, the disclosed system includes a restraint container and an expandable medium. The restraint container includes a base and a cover and has a volume. The restraint container is configured to enclose at least a portion of a composite structure. The expandable medium is configured to be disposed in the volume between at least a portion of the restraint container and the composite structure. The volume of the restraint container is selectively variable.

[0005] In one embodiment, the disclosed method includes the steps of: (1) enclosing at least a portion of a composite structure in a restraint container; (2) selectively varying a volumetric space of the restraint container; (3) expanding an expandable medium disposed in the volumetric space; and (4) curing the composite structure.

[0006] In one embodiment, a composite workpiece of the present disclosure comprises a composite structure including a plurality of composite layers, at least some of which are uncured. The composite structure is supported by a base of a restraint container. At least a portion of the composite structure is enclosed in a cover of the restraint container, the cover having a plurality of walls and a volume. At least one of the walls is movable relative to at least one other of the walls to selectively change the volume. An expandable medium is disposed in the volume of the cover between the cover and the composite structure and is configured to expand to a predetermined volume upon a predetermined change in an attribute of the expandable medium, thereby applying a positive pressure to the composite structure and the cover.

[0007] Other embodiments of the disclosed systems, methods, and composite workpieces will be apparent from the following detailed description, the accompanying drawings, and the claims. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic block diagram of a composite structure curing system. [Figure 2] FIG. 1 is a flow diagram of an embodiment of a method for curing a composite structure. [Figure 3] 1 is a schematic cross-sectional view of an embodiment of a restraint container for a system applied to a composite structure. FIG. [Figure 4] 4 is a schematic cross-sectional view of the embodiment of the system shown in FIG. 3, showing an expandable medium disposed in the volume of the restraint container. [Figure 5] 5 is a schematic cross-sectional view of the embodiment of the system shown in FIG. 4 after the expansion medium has expanded. [Figure 6] FIG. 2 is a schematic cross-sectional view of an embodiment of the system. [Figure 7] FIG. 2 is a schematic cross-sectional view of an embodiment of the system. [Figure 8] FIG. 2 is a schematic cross-sectional view of an embodiment of the system. [Figure 9] FIG. 2 is a schematic cross-sectional view of an embodiment of the system. [Figure 10] FIG. 2 is a schematic cross-sectional view of an embodiment of the system. [Figure 11] FIG. 2 is a schematic cross-sectional view of an embodiment of the system. [Figure 12] 1 is a schematic perspective view of an embodiment of an aircraft hat stiffener. FIG. [Figure 13] 1 is a schematic perspective view of an example of an aircraft wing including a stiffener; [Figure 14] FIG. 1 is a flow diagram of an embodiment of an aircraft production and service method. [Figure 15] FIG. 1 is a schematic block diagram of an embodiment of an aircraft. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1-11 , the present disclosure relates to, by way of example, a system 100 and method 1000 for curing a composite structure 200. Embodiments of the system 100 and method 1000 provide "out-of-autoclave" curing, achieving substantially equivalent autoclave quality composite components without the need for processing in an autoclave or the need for large, expensive equipment. The curing process achieved by the present system 100 and / or method 1000 allows for lower cost, faster, and space-saving curing.

[0010] This disclosure recognizes that many composite parts require the application of heat and pressure to cure (solidify) the composite in an autoclave. The use of an autoclave requires significant equipment space and energy costs. The system 100 and method 1000 described herein, for example, allow for the use of an expandable material, such as foam, to provide the necessary pressure for curing and, optionally, controlled heating.

[0011] In various embodiments, a portion of a pre-cured or partially cured composite component is enclosed or otherwise constrained within a curing vessel. Typically, the vessel is designed to conform to the shape and geometry of the composite component and to contain the intumescent material. In various embodiments, the intumescent material is disposed between the vessel and the composite component. In various embodiments, the intumescent material is activated to expand within the vessel. In various embodiments, heat is used to activate the intumescent material. In some embodiments, heat is also used to accelerate the curing of the composite.

[0012] Advantages of system 100 and method 1000 include eliminating or reducing the need for large autoclaves, improving factory layout and energy consumption. Embodiments of system 100 and method 1000 also allow for the use of intumescent materials in combination with applied heat to cure the composite. Additionally, repair cures and post-cures can be performed without the need to re-enter the autoclave. Furthermore, embodiments of system 100 and method 1000 provide the option of curing or repairing composite parts outside of the factory or other manufacturing environments.

[0013] Next, an embodiment of a system 100 of the present disclosure will be described below with reference to FIGS. 1 and 3 to 11. The system 100 includes a certain number of elements, features, and components. Not all elements, features, or components described or illustrated in one embodiment are necessarily required for that embodiment. Some or all of the elements, features, and components described or illustrated in one embodiment can be combined in various ways with other embodiments. Such combinations are not required to include other elements, features, or components described in those other embodiments, even if such embodiments are not explicitly described or illustrated herein.

[0014] 1 is a schematic block diagram illustrating one or more embodiments of a system 100. In various embodiments, as described in more detail below, the system 100 includes a number of components, including one or more of a constraining container 102, a cover 106, a base 104, a wall 112, an overlay 168, a retention mechanism 120, a clamp 122, a robotic manipulator 124, an expandable medium 130, a rigid form 142, a molding surface 144, an intermediate layer 164, a cowl 146, a barrier 162, a casting 156, an encapsulation element 154, a bladder 178, an expandable element 196, a heater 158, an actuator 108, a sensor 166, a controller 176, an expansion chamber 192, a pressure chamber 194, and a valve 148.

[0015] 3-11 illustrate various embodiments of the system 100 in use to cure a composite structure 200. The overall footprint of the system 100 may vary, including the overall size of the restraint container 102 of the system 100, depending on the application. In various embodiments, the footprint of the system 100, including the overall size of the restraint container 102 during operation, is smaller than the overall size of the composite structure 200 being cured. In such embodiments, the system 100 may locally or independently cure portions 202 of the composite structure 200. Generally, the portions 202 of the composite structure 200 refer to portions of the composite structure 200 that are to be cured (e.g., locally or independently). For example, the portions 202 may include or refer to at least one uncured portion, a partially cured portion, or a portion of the composite structure 200 that requires repair. However, in other embodiments, the footprint of the system 100, e.g., the overall size of the restraint container 102 during operation, is substantially the same as or larger than the overall size of the composite structure 200 being cured, thereby allowing the entire composite structure 200 to be cured outside of an autoclave.

[0016] In various embodiments, the system 100 is an adjustable tooling system that includes a restraining container 102 and an expanding medium 130 ( FIGS. 3-11 ). In some embodiments, the restraining container 102 is capable of containing the entire composite structure 200 to be cured, such that the entire composite structure 200 and the expanding medium 130 are disposed within the restraining container 102 and are restrained thereby. In other embodiments, the restraining container 102 is selectively positioned relative to a portion 202 of the composite structure 200, such that at least the portion 202 of the composite structure 200 and the expanding medium 130 are disposed within the restraining container 102 and are restrained thereby. The system 100 is configured to apply a positive pressure to the portion 202 of the composite structure 200 by expanding the expanding medium 130 during the process of curing the portion 202 of the composite structure 200. In various embodiments, the composite structure 200 may be in an uncured state, partially cured state, or in need of repair. The containment container 102 and the expansion medium 130 are configured to apply a positive pressure to the composite structure 200 during the curing process of the composite structure 200.

[0017] Referring to FIG. 1 , in various embodiments, composite structure 200 is a composite part, component, object, etc., comprised of one or more composite layers 208 (also referred to as plies) bonded together through curing (e.g., by applying heat and / or pressure). Composite structure 200 can include any suitable number of composite layers 208. In various embodiments, composite structure 200 includes one or more polymeric materials, thermoplastic materials, thermoset materials, fiber-reinforced materials, and / or other suitable materials, depending on the desired properties of the finished workpiece. In one or more embodiments, at least a portion of composite layers 208 is uncured or partially cured, or is a repair patch or filler material (e.g., composite patch 214). In one or more embodiments, the activation temperature 152 of the expandable medium 130 (e.g., expandable pellets 136) is lower than the curing temperature 212 of the composite layer 208, e.g., lower than the curing temperature of at least a portion of the composite layer 208 that is uncured or partially cured or formed into a repair patch (e.g., composite patch 214). In one or more embodiments, the activation temperature 152 of the expandable medium 130 (e.g., expandable pellets 136) is the same as or higher than the curing temperature 212 of the composite layer 208, e.g., higher than the curing temperature of at least a portion of the composite layer 208 that is uncured or partially cured or formed into a repair patch (e.g., composite patch 214). In one or more embodiments, the activation temperature 152 of the expandable medium 130 (e.g., expandable pellets 136) is greater than the curing temperature 212 of the composite layer 208, e.g., greater than the curing temperature of at least a portion of the composite layer 208 that is uncured or partially cured, or that is formed into a repair patch (e.g., composite patch 214).

[0018] 1 and 3-11 , in one or more embodiments, the restraint container 102 includes a base 104 and a cover 106. The restraint container 102, e.g., at least the cover 106, has (e.g., forms or defines) an interior volume 114. The restraint container 102 is configured to enclose at least a portion of the composite structure 200. An expandable medium 130 is configured to be disposed in the interior volume 114 between at least a portion of the restraint container 102 and the composite structure 200. The interior volume 114 of the restraint container 102 is selectively (e.g., controllably) variable.

[0019] In one or more embodiments, the volume space 114 can be selectively altered or changed to controllably reduce the volume space 114. Selectively reducing the volume space 114 can correspondingly reduce the amount of expansion medium 130 required to fill the volume space 114 upon expansion. In one or more embodiments, the volume space 114 can be selectively altered or changed to controllably expand the volume space 114. Selectively reducing or expanding the volume space 114 can dynamically control the positive pressure exerted by the expansion medium 130 upon expansion.

[0020] In one or more embodiments, cover 106 comprises a portion of restraint container 102, such as when composite structure 200 is supported by base 104. In such embodiments, base 104 may also comprise a portion of restraint container 102. In one or more embodiments, cover 106 comprises the entire restraint container 102, such as when composite structure 200 is supported by other stiffening members or is not supported at all.

[0021] In one or more embodiments, the cover 106 is selectively positioned relative to the composite structure 200 such that at least the portion 202 of the composite structure 200 and the expandable medium 130 are positioned within the cover 106 and are constrained by the cover 106. The cover 106 is movable relative to the composite structure 200 and the base 104, respectively, thereby allowing selection, isolation, and configuration of which portions of the composite structure 200 are to be cured. The movement of the cover 106 allows for localized curing of individual regions or portions of the composite structure 200. In one or more embodiments, the cover 106 can be entirely removed from the composite structure 200, for example, after curing. In such embodiments, the cover 106 includes (e.g., forms or defines) the volume 114 and is configured to encapsulate the portion 202 of the composite structure 200.

[0022] In one or more embodiments, the cover 106 has a size and dimensions suitable to cover the entire cured composite structure 200. In such embodiments, the dimensions (e.g., length and width) of the cover 106 are equal to or greater than the dimensions (e.g., length and width) of the composite structure 200. In one or more embodiments, the cover 106 is movable and selectively positioned along the length of the composite structure 200.

[0023] In one or more embodiments, the cover 106 has a size and dimensions suitable to cover at least the portion 202 to be cured. In such embodiments, the dimensions (e.g., length and width) of the cover 106 are less than at least one of the dimensions (e.g., length and width) of the composite structure 200. In one or more embodiments, the cover 106 is movable and selectively positioned along the length of the composite structure 200.

[0024] 1 , the cover 106 has a cross-sectional profile 118. In one or more embodiments, the cross-sectional profile 118 of the cover 106 corresponds to the cross-sectional shape 204 of the composite structure 200. By at least generally matching the cross-sectional profile 118 of the cover 106 with the cross-sectional shape 204 of the portion 202 of the composite structure 200 to be cured, a reduction in the volumetric space 114 that must be filled with the expandable medium 130 upon inflation can be achieved.

[0025] In one or more embodiments, the cover 106 has a perimeter 116. In one or more embodiments, if the system 100 is intended for localized stiffening of the portion 202 of the composite structure 200, at least a portion of the perimeter 116 is configured to contact the composite surface 206 of the composite structure 200. The contact between the perimeter 116 of the cover 106 and the composite surface 206 of the composite structure 200 can confine the expandable medium 130 disposed in the volume 114. In such embodiments, the portion 202 of the composite structure 200 is disposed within or surrounded by the perimeter 116 of the cover 106. In one or more embodiments, at least a portion of the perimeter 116 of the cover 106 is configured to be sealed to the composite surface 206 of the composite structure 200. Sealing the periphery 116 of the cover 106 to the composite surface 206 of the composite structure 200 allows for the use of vacuum pressure (e.g., negative pressure) during the curing process and as a means to hold the cover 106 in place on the composite surface 206.

[0026] In various embodiments, the cover 106 includes any suitable element or feature for facilitating the introduction and removal of the expansion medium 130 from the volume 114. In one or more embodiments, the cover 106 includes a removable or openable panel (e.g., a door) that can be positioned over the composite structure 200 to provide access to the volume 114 and introduce the expansion medium 130.

[0027] In one or more embodiments, at least a portion of the cover 106 is heat reflective. In one or more embodiments, at least one of the walls 112 of the cover 106 is heat reflective. In one or more embodiments, at least a portion of the interior surface of the cover 106 includes or is coated with a heat reflective material. The heat reflective nature of the cover 106 can facilitate heating of the expandable medium 130 during the curing process, thereby initiating expansion of the expandable medium 130.

[0028] 1 and 3-11 , in one or more embodiments, the cover 106 of the restraint container 102 includes a plurality of walls 112. In one or more embodiments, the walls 112 form or define at least a portion of the volume 114. In one or more embodiments, the walls 112 have or form a cross-sectional profile 118 of the cover 106. At least one of the walls 112 is movable relative to at least one other of the walls 112 to selectively change the volume 114 of the restraint container 102. In one or more embodiments, the expandable medium 130 is disposed between at least one of the walls 112 of the cover 106 and the composite structure 200.

[0029] At least one of the walls 112 can be selectively moved relative to at least one other of the walls 112 to selectively control (e.g., expand or contract) the volume space 114 formed by the walls 112. At least one of the walls 112 can be selectively moved relative to at least one other of the walls 112 to selectively control (e.g., increase or decrease) the positive pressure generated upon inflation of the inflation medium 130.

[0030] In such an embodiment, the expandable medium 130 is configured to be disposed within the volume 114 of the cover 106 defined by the walls 112. In one or more embodiments, the expandable medium 130 is disposed between the walls 112 and at least the portion 202 of the composite structure 200 to be cured.

[0031] In one or more embodiments, at least a portion of cover 106, such as wall 112 of cover 106, is rigid (e.g., hard or non-flexible) and non-distensible. In such embodiments, at least a portion of cover 106, such as wall 112, is constructed of any suitable material, including, but not limited to, a metallic material, a composite material, a cementitious material, a ceramic material, or a polymeric material. In such embodiments, wall 112 restrains expansion medium 130 and resists the positive pressure generated upon expansion of expansion medium 130. In such embodiments, wall 112 can withstand the pressure generated within containment container 102 upon expansion of expansion medium 130.

[0032] 1 and 6-8 , in one or more embodiments, the actuator 108 is configured to move at least one of the walls 112 relative to at least one other of the walls 112. The actuator 108 selectively moves at least one of the walls 112 comprising the cover 106 relative to one another to change the volume 114 of the containment container 102. In such embodiments, the actuator 108 is coupled to the walls 112. Actuation of the actuator 108 can cause movement of the walls 112. The actuator 108 can be any suitable type of controllable actuation device, such as a mechanical actuator, a pneumatic actuator, a linear actuator, a rotary actuator, or the like.

[0033] 3-8 , in one or more embodiments, the plurality of walls 112 includes a plurality of side walls 184 and a top wall 182. As shown in FIG. 8 , in some embodiments, the walls 112 also include a bottom wall 188. In such embodiments, the bottom wall 188 is positioned or coupled to function as the base 104 of the restraint container 102. In one or more embodiments, the top wall 182 is movable relative to the side walls 184 and / or the bottom wall 188 to selectively vary the volume space 114 of the restraint container 102. In one or more embodiments, at least one of the side walls 184 is movable relative to another one of the side walls 184 to selectively vary the volume space 114 of the restraint container 102. In one or more embodiments, at least one of the side walls 184 is movable relative to the top wall 182 and / or the bottom wall 188 to selectively vary the volume space 114 of the restraint container 102. In one or more embodiments, each side wall 184 is movable relative to one of the side walls 184, the top wall 182, and / or the bottom wall 188 to selectively vary the volume space 114 of the restraint container 102. In one or more embodiments, the top wall 182 is movable relative to one or more of the side walls 184 and / or the bottom wall 188 to selectively vary the volume space 114 of the restraint container 102.

[0034] Selective relative movement of the top wall 182, one or more side walls 184, and / or bottom wall 188 relative to one another provides increased flexibility and control of the volume 114 defined by the walls 112. Selective relative movement of the top wall 182, one or more side walls 184, and / or bottom wall 188 relative to one another provides increased flexibility and control of the positive pressure generated by the inflation medium 130 during inflation.

[0035] 1, 6, and 8, in one or more embodiments, actuator 108 is configured to move top wall 182 relative to side wall 184. In such embodiments, at least a portion of expandable medium 130 is disposed between top wall 182 and composite structure 200.

[0036] 1 and 8 , in one or more embodiments, the system 100 includes a plurality of actuators 108. In one or more embodiments, the actuators 108 are configured to move the top wall 182 and at least one of the side walls 184. In one or more embodiments, the actuators 108 are configured to move the top wall 182 and each of the side walls 184. In some embodiments, the actuators 108 are further configured to move the bottom wall 188. In such embodiments, at least a portion of the expandable medium 130 is disposed between the top wall 182 and the composite structure 200. Additionally or alternatively, in such embodiments, at least a portion of the expandable medium 130 is also disposed between at least one or each of the side walls 184 and the composite structure 200.

[0037] Selective movement of the top wall 182, one or more side walls 184, and / or bottom wall 188 relative to one another and to the expandable medium 130 disposed between the top wall 182, one or more side walls 184, and / or bottom wall 188 allows for selectively controlled application of positive pressure to various regions of the composite structure 200 and accommodates a variety of different shapes and configurations of the composite structure 200. The joint 198 may include any suitable movable joint having one or more degrees of freedom, including, but not limited to, a hinge joint, a ball joint, a collinear joint, a rotational joint, a revolving joint, an orthogonal joint, a twisting joint, etc.

[0038] 8 , in one or more embodiments, the wall 112 is movable relative to the actuator 108. For example, the wall 112 (e.g., at least one or each of the plurality of walls 112) is coupled to a rod or working end of the actuator 108 (a corresponding one of the plurality of actuators 108) by a joint 198. In such embodiments, the joint 198 allows for adjustment or adaptation of the angular orientation of the wall 112 in response to the inflation of the inflation medium 130.

[0039] In the embodiment shown in Figure 6, at least one of the walls 112 (e.g., the top wall 182) is moved relative to at least one other of the walls 112 (e.g., the side wall 184). The top wall 182, the side wall 184, and the base 104 define a volume 114 of the containment container 102. The expandable medium 130 and a portion of the composite structure 200 are disposed within the volume 114 and are constrained by the containment container 102. An actuator 108 is coupled to the top wall 182. Actuation (e.g., extension / contraction) of the actuator 108 controls the movement of the top wall 182 such that moving the top wall toward the composite structure 200 reduces the volume 114 and moving the top wall away from the composite structure 200 expands the volume 114. In an exemplary embodiment, the volume 114 may not be sealed (e.g., not airtight), meaning that a sealant may not be (e.g., is not required to be) disposed between the top wall 182 and the side wall 184.

[0040] In the embodiment shown in FIG. 6 , the composite structure 200 is supported by the base 104. The cover 106 is positioned relative to the base 104 and the composite structure 200 to enclose at least the portion of the composite structure 200 to be cured. The expandable medium 130 is positioned (e.g., deposited) in the volumetric space 114 of the containment container 102. The actuator 108 moves the top wall 182 relative to the side wall 184 toward the composite structure 200, thereby reducing the volumetric space 114. The expandable medium 130 is activated during the curing process, expanding to fill the volumetric space 114 and applying a positive pressure to the composite structure 200. In such an embodiment, the positive pressure created by the expansion of the expandable medium 130 acts on the composite structure 200, thereby facilitating curing.

[0041] 1 and 7 , in one or more embodiments, cover 106 (e.g., wall 112) includes side wall 184, top wall 182, and cap 186. In such embodiments, cap 186 can be considered one of walls 112, and cap 186 divides volume 114 of containment container 102 into two separate spaces: an expansion chamber 192 and a pressure chamber 194. Expansion chamber 192 is defined by top wall 182, a portion of side wall 184, and cap 186. Pressure chamber 194 is defined by the interior of cap 186, a portion of side wall 184, and base 104. Expandable medium 130 is disposed within expansion chamber 192 (e.g., between top wall 182 and cap 186) and is constrained (e.g., surrounded) by top wall 182, a portion of side wall 184, and cap 186. At least a portion of the composite structure 200 is disposed within the pressure chamber 194 (e.g., between the cap 186 and the base 104) and is constrained (e.g., surrounded) by the cap 186, a portion of the sidewall 184, and the base 104. The cap 186 is movable relative to the sidewall 184 and the top wall 182 to selectively change the volume of the pressure chamber 194. As the expandable medium 130 expands, the cap 186 is forced toward the composite structure 200, decreasing the volume of the pressure chamber 194. This increases the pressure within the pressure chamber 194 and acting on the composite structure 200. In an exemplary embodiment, the pressure chamber 194 is sealed (e.g., airtight), meaning that a sealant or the like is disposed between the cap 186 and the sidewall 184. In other words, the cap 186 is sealed to the sidewall 184 and is movable relative to the sidewall.

[0042] In the embodiment shown in FIG. 7 , the composite structure 200 is supported by the base 104. The cover 106 is positioned relative to the base 104 and the composite structure 200. At least the portion of the composite structure 200 to be cured is enclosed in a pressure chamber 194 of the restraint container 102. The expansion medium 130 is positioned (e.g., deposited) in an expansion chamber 192 of the restraint container 102. The expansion medium 130 is activated during the curing process, expanding to fill the expansion chamber 192 and apply a positive pressure to the cap 186. As the expansion medium 130 expands, it forces the cap 186 toward the composite structure 200 relative to the sidewall 184, reducing the volume of the pressure chamber 194. This increases the pressure within the pressure chamber 194 and the pressure acting on the composite structure 200 during the curing process. In such an embodiment, the positive pressure created by the expansion of the expandable medium 130 acts on the cap 186, increasing the gas pressure acting on the composite structure 200, thereby accelerating curing.

[0043] 1, 6, and 7, in one or more embodiments, the sensor 166 is configured to sense or otherwise determine pressure or force acting on the composite structure 200 during curing and / or due to the expansion of the expandable medium 130. In such embodiments, the controller 176 (FIG. 1) receives input signals or data from the sensor 166 and controls and / or maintains the pressure acting on the composite structure 200 at a desired level. The sensor 166 may be, for example, any type and number of pressure sensors, load sensors, or other sensor devices.

[0044] In one or more embodiments, the controller 176 includes or uses closed-loop control to control the pressure within the restraint container 102 and the pressure acting on the composite structure 200. In one or more embodiments, the volume 114 can be varied in response to real-time pressure measured by the sensor 166. Closed-loop control can improve the quality of composite manufacturing and repair because the closed-loop mechanism can compensate for a number of variables, such as differences in different batches of material, humidity, and environmental temperature. In one or more embodiments, the controller 176 controls the pressure within the restraint container 102 and the pressure acting on the composite structure 200 by expanding or contracting the volume 114 based on the pressure measurements from the sensor 166. Specifically, this control is achieved by selectively changing the position of one or more walls 112, selectively expanding or contracting the inflatable element 196, or selectively expanding or contracting the inflatable medium 130 within the volume 114.

[0045] In one or more embodiments, such as shown in FIG. 6 , the sensor 166 is configured to detect a force or load applied by the expandable medium 130 to the top wall 182 (or another movable one of the walls 112) as the expandable medium 130 expands within the volume 114 during the curing process. For example, the actuator 108 moves the top wall 182 toward the unexpanded expandable medium 130 and the composite structure 200, thereby reducing the volume 114 of the restraint container 102. When activated, the expandable medium 130 expands to fill the volume 114, thereby applying a positive pressure to the composite structure 200 and the top wall 182. The sensor 166 detects the force applied by the expanded expandable medium 130 to the top wall 182 and transmits the data to the controller 176. In one or more embodiments, the controller 176 includes a processor, memory, and program code configured to process this sensor data. In one or more embodiments, the controller 176 determines the pressure within the volume 114 and / or the pressure acting on the composite structure 200 based on the sensor data. If the controller 176 determines that a lower pressure is required for proper curing, the controller 176 commands the actuator 108 to move the top wall 182 away from the expandable medium 130 and the composite structure 200, thereby decreasing the pressure acting on the composite structure 200. On the other hand, if the controller 176 determines that a higher pressure is required for proper curing, the controller 176 commands the actuator 108 to move the top wall 182 toward the expandable medium 130 and the composite structure 200, thereby increasing the pressure acting on the composite structure 200.

[0046] In one or more embodiments, such as that shown in FIG. 7 , the sensor 166 is configured to detect a force or load acting on the top wall 182 (or another movable one of the walls 112) due to internal pressure generated in the pressure chamber 194 as the expansion of the expansion medium 130 within the expansion chamber 192 during the curing process. For example, when activated, the expansion medium 130 expands to fill the expansion chamber 192, thereby applying a positive pressure to the top wall 182 and the cap 186. In such embodiments, the expansion medium 130 functions as an external actuator. The sensor 166 detects the force acting on the cap 186 due to the internal pressure generated in the pressure chamber 194 as the expansion of the expansion medium 130 occurs and transmits the data to the controller 176. In one or more embodiments, the controller 176 determines the pressure within the pressure chamber 194 and / or the pressure acting on the composite structure 200 based on the sensor data. If controller 176 determines that the pressure is too high for proper curing, controller 176 commands valve 148 to partially release the gas within pressure chamber 194, thereby reducing the pressure within pressure chamber 194 and / or the pressure acting on composite structure 200. In such embodiments, valve 148 may include any suitable controllable pressure-regulating valve. In one or more embodiments, valve 148 may be configured to automatically release a portion of the gas within pressure chamber 194 when a predetermined pressure is reached in pressure chamber 194, thereby reducing the pressure within pressure chamber 194 and / or the pressure acting on composite structure 200. In such embodiments, valve 148 may include any suitable controllable pressure-regulating valve.

[0047] In one or more embodiments, the expansion and / or contraction of the expansion medium 130 is selectively controllable. For example, the expansion medium 130 is configured to selectively or controllably expand and contract, thereby serving as a means for controlling the pressure within the containment container 102 and / or the pressure acting on the composite structure 200. In various embodiments, the expansion and / or contraction of the expansion medium 130 can be controlled in any of a variety of ways, such as, for example, by heating or cooling the expansion medium 130.

[0048] In other embodiments, the system 100 includes additional mechanisms for preventing overpressure and / or regulating the pressure within the volume 114 of the containment container 102. As an example, the cover 106 may be secured in place relative to the composite structure 200 and may be coupled to the base 104 by, for example, a plurality of shear pins. In such embodiments, the shear pins may be configured to break at a predetermined pressure, thereby releasing the cover 106 and reducing the pressure.

[0049] 1 , in one or more embodiments, the cover 106 includes an overlay 168. In one or more embodiments, the overlay 168 forms or defines at least a portion of the volume 114. In one or more embodiments, the overlay 168 has or forms a cross-sectional profile 118 of the cover 106 that corresponds to the cross-sectional shape 204 of the composite structure 200. In such embodiments, the expandable medium 130 is disposed within the volume 114 defined by the overlay 168, between the overlay 168 of the cover 106 and the composite structure 200.

[0050] In one or more embodiments, at least a portion of the cover 106, e.g., the overlay 168 of the cover 106, is flexible and non-distensible. The use of such an overlay 168 allows the cover 106 to mold to a shape that conforms to (e.g., more closely matches) the contours of the composite structure 200 and / or the expandable medium 130 disposed between the cover 106 and the composite structure 200 prior to inflation of the expandable medium 130. In such embodiments, at least a portion of the cover 106, e.g., the overlay 168, can be formed from any suitable material, including, but not limited to, metal mesh (e.g., chainmail), ceramic mesh, polymer mesh, etc. In such embodiments, the overlay 168 restrains the expandable medium 130 and resists the positive pressure generated by the expandable medium 130 upon inflation. In such embodiments, the overlay 168 can withstand the pressure generated within the containment container 102 upon inflation of the expandable medium 130.

[0051] In one or more embodiments, at least a first portion of cover 106 is flexible and non-distensible, and at least a second portion of cover 106 is rigid and non-distensible. As one example, cover 106 can include overlay 168 and at least one of walls 112. In other embodiments, at least a first portion of cover 106 is non-distensible (e.g., flexible and / or rigid), and at least a second portion of cover 106 is distensible.

[0052] 1 and 3-11 , in one or more embodiments, the base 104 supports at least a portion of the composite structure 200. In one or more embodiments, the base 104 forms part of the restraint container 102. As one example, the composite structure 200 is positioned on or supported by the base 104. As another example, the base 104 structurally reinforces or serves to reinforce at least the portion 202 of the composite structure 200 that is enclosed by the cover 106 and that is to be cured by the system 100. In such an embodiment, the cover 106 is movable relative to the base 104. In one or more embodiments, as shown in FIGS. 3-5 , the composite structure 200 is positioned on the base 104 during the curing process. Applying an appropriate compressive force (e.g., positive pressure) to the composite structure 200 while it is in the restraint container 102 may require that at least the portion 202 of the composite structure 200 to be cured be adequately supported. In one or more embodiments, the base 104 provides a substantially incompressible surface that supports the underside of the composite structure 200 .

[0053] In one or more embodiments, base 104 is substantially resistant to compression, at least capable of withstanding compression when pressure is applied to an upper surface (e.g., molding surface 144) of base 104 that contacts a lower surface of composite structure 200. In this manner, pressure applied to an outer surface (e.g., composite surface 206) of composite structure 200 acts in conjunction with base 104 to generate a compressive force on composite structure 200.

[0054] In one or more embodiments, the base 104 has a suitable shape that defines or corresponds to the desired cross-sectional shape 204 of the composite structure 200. In one or more embodiments, the base 104 includes a rigid mold 142. In one or more embodiments, the rigid mold 142 includes a molding surface 144. In one or more embodiments, the molding surface 144 corresponds to the cross-sectional shape 204 of the composite structure 200. As shown in FIG. 3, in one or more embodiments, the rigid mold 142 has a suitable upper molding surface 144 that can shape and / or support the three-dimensional shape of the composite structure 200. As shown in FIG. 9, in one or more embodiments, the rigid mold 142 has a planar or flat molding surface 144 that can shape and / or support the two-dimensional shape of the composite structure 200.

[0055] In one or more embodiments, the base 104 is a mold used during the layup and formation of the composite structure 200. In one or more embodiments, the base 104 is a cure tool used during a cure process, such as an initial cure in an autoclave. In one or more embodiments, the base 104 is a repair tool used during a localized cure process, such as a second out-of-autoclave cure or repair process.

[0056] 1 and 9-11 , in one or more embodiments, the retention mechanism 120 is configured to hold the cover 106 against the composite structure 200. The retention mechanism 120 may include any suitable mechanism capable of securing the cover 106 relative to the composite structure 200 during a curing process. In one or more embodiments, the retention mechanism 120 is configured to couple the cover 106 to the base 104. In such an embodiment, the cover 106 and the base 104 combine to form the restraining container 102, which contains at least the portion 202 of the composite structure 200 and the expandable medium 130 during a curing process. In one or more embodiments, the retention mechanism 120 is configured to couple to the rigid mold 142 of the base 104. In one or more embodiments, the retention mechanism 120 is configured to couple to the rigid mold 142 of the base 104. In one or more embodiments, a portion of the periphery 116 of the cover 106 is configured to contact the base 104 that supports the composite structure 200 .

[0057] In one or more embodiments, the retention mechanism 120 includes at least one clamp 122. In such embodiments, the clamp 122 fastens or secures the cover 106 in place relative to the composite structure 200. In one or more embodiments, the clamp 122 fastens or secures the cover 106 to the composite structure 200. In one or more embodiments, the clamp 122 fastens or secures the cover 106 to another component (e.g., the base 104 or a secondary structure). The clamp 122 may include, for example, any suitable type of clamping or fastening device, including, but not limited to, mechanical clamps, magnetic clamps, pneumatic clamps, spring clamps, latches, pins, fasteners, weights, etc. The retention mechanism 120 may include any number of clamps 122.

[0058] 1 , in one or more embodiments, holding mechanism 120 includes robotic manipulator 124. In such embodiments, robotic manipulator 124 holds or secures cover 106 in a predetermined position relative to composite structure 200. In such embodiments, cover 106 is coupled to a working end (e.g., an end effector) of robotic manipulator 124. Robotic manipulator 124, under computer control, selectively positions cover 106 relative to composite structure 200 and holds cover 106 in the proper position for curing portion 202 of composite structure 200.

[0059] 1 and 9-11, in one or more embodiments, the expandable medium 130 is disposed within an encapsulation element 154. In such embodiments, the encapsulation element 154 encapsulates the expandable medium 130 (e.g., expandable pellets 136), which facilitates handling of the expandable medium 130 and facilitates removal of the expandable medium 130 after curing is complete. In one or more embodiments, the encapsulation element 154 is non-expandable. In one or more embodiments, the encapsulation element 154 is expandable. The encapsulation element 154 can take any suitable form, such as a sealing film, a sealing material layer, a bag, a pouch, or the like.

[0060] 1 and 9-11 , intermediate layer 164 is disposed or positioned between inflatable medium 130 and at least portion 202 of composite structure 200. In one or more embodiments, intermediate layer 164 includes or takes the form of barrier 162 (e.g., a barrier film), cowl 146 (e.g., a plate or sheet cowl), or other suitable layer of material (e.g., casting 156, bladder 178, etc.). In such embodiments, intermediate layer 164 is disposed prior to adding inflatable medium 130 to volume 114 of restraint container 102.

[0061] In one or more embodiments, the barrier 162 promotes reduced porosity and / or improved consolidation, as shown in Figure 9. The barrier 162 can be selected to be heat resistant and easily removable after curing of the composite structure 200. Examples of materials for the barrier 162 include silicone-based films, polymer-based films, and / or fluorinated polymer-based films. In one or more embodiments, the barrier 162 is incorporated into a vacuum bag that contains the composite structure 200.

[0062] In one or more embodiments, cowl 146 facilitates improved compaction and surface condition of composite structure 200. Cowl 146 may be selected to be heat resistant and easily removable after curing of composite structure 200. Examples of cowl 146 materials include rigid or semi-rigid materials, metallic materials, composite materials, etc.

[0063] In one or more embodiments, cowl 146 includes or is formed of multiple cowl sections, as shown in FIG. 10 . In such embodiments, each cowl section is separate from the other cowl sections and is movable (e.g., displaceable or slidable) relative to adjacent cowl sections. In one or more embodiments, adjacent cowl sections are disposed end-to-end. The separate cowl sections of cowl 146 facilitate improved compaction and surface condition.

[0064] In one or more embodiments, as shown in FIG. 11 , the intermediate layer 164 includes or takes the form of a casting 156. In one or more embodiments, the casting 156 is disposed between the expandable medium 130 and the composite surface 206 of the composite structure 200. In such embodiments, the casting 156 is configured to solidify in response to a change in temperature, time, or other attribute of the material of the casting 156. By way of example, the casting 156 is disposed or formed on the portion 202 of the composite structure 200 prior to the application of the expandable medium 130. In one or more embodiments, the casting 156 is configured to solidify before or during the curing process. The casting 156 can be selected to be heat resistant and easily removable after the composite structure 200 has cured. In one or more embodiments, the casting 156 facilitates an improved degree of compaction. The casting 156 can be selected to be heat resistant and easily removable after the composite structure 200 has cured. Examples of materials for the casting 156 include, but are not limited to, epoxy, rubber, plaster, cement, and the like.

[0065] In one or more embodiments, the casting 156 includes a casting material. In one or more embodiments, the casting material is configured to solidify upon a predetermined change in an attribute of the casting material. For example, the casting material can solidify in response to a change in temperature, time, chemical composition, pressure, or other attribute of the material of the casting 156. In one or more embodiments, the casting material is heat-activated. In such embodiments, the predetermined change in the attribute of the casting material can include a change in the temperature of the casting material and / or a change in the temperature of one or more portions of the casting material. Thus, causing the predetermined change in the attribute of the casting material can include increasing the temperature of the casting 156 from a low temperature, such as ambient temperature (e.g., room temperature), to at least an initial temperature or a predetermined temperature above ambient temperature (e.g., a temperature several degrees above ambient temperature suitable for generating a predetermined expansion of the expansile element). The casting material solidifies or hardens as a result of this temperature increase. In such an embodiment, the heat-activated casting material is configured to solidify when the temperature of the casting material increases to at least a predetermined temperature. In one or more embodiments, the predetermined change in the attribute of the casting material is a combination of two or more properties of the casting material, such as a ratio or product of quantitative values ​​associated with the properties of the casting material. In one or more embodiments, the casting material includes two materials (e.g., a binary mixture) such as a base and a curing agent (e.g., a reactant, catalyst, or accelerator) that solidify or harden through a chemical reaction when mixed. In one or more embodiments, the casting material includes a resin-based composite that solidifies or hardens when exposed to a specific wavelength of light (e.g., blue light in the 400-500 nm range). In one or more embodiments, solidification of the casting 156 can be achieved or accelerated by a combination of solidification techniques, such as, for example, heat and binary mixing, heat and ultraviolet (UV) curing, or other combinations. If heat is required to solidify or accelerate the solidification of the casting 156, the heating temperature is generally below the cure temperature of the composite material.

[0066] In one or more embodiments, the casting material is heat reflective or includes a heat reflective material, liner, or layer. As an example, the casting 156 can include at least one heat reflective film as one of the layers in the cast. The heat reflective film can be the innermost layer, a middle or inner layer, and / or the outermost layer of the cast. The heat reflective nature of the casting 156 facilitates facilitating heating of the expandable medium 130 during the curing process to cause expansion of the expandable medium 130.

[0067] In one or more embodiments, as shown in FIG. 10 , the intermediate layer 164 includes or takes the form of a bladder 178. In one or more embodiments, the bladder 178 is filled with a fluid (e.g., gas or liquid) to facilitate improved compaction and surface condition of the composite structure 200. In one or more embodiments, the bladder 178 is configured to equalize the positive pressure acting on the composite structure 200, providing a more uniform positive pressure across the composite surface 206. The bladder 178 can be selected to be heat resistant and easily removable after the composite structure 200 has cured.

[0068] In other embodiments, the system 100 includes multiple intermediate layers 164, such as two or more of the encapsulation element 154, the cowl 146, the casting 156, the barrier 162, and the like, or a combination thereof.

[0069] 1 , in one or more embodiments, the inflation medium 130 is configured to expand to a predetermined volume 132 when a predetermined change occurs in a property 134 of the inflation medium 130, such that the inflation medium 130 applies a positive pressure to the composite structure 200 and the cover 106 of the restraint container 102. In one or more embodiments, the predetermined volume 132 of the inflation medium 130 in an expanded state is larger than the volume space 114 of the restraint container 102. Generally, this "predetermined volume" refers to the interior volume (e.g., volume space 114) that can actually fill the interior cavity of the restraint container 102. In various embodiments, the predetermined volume 132 is substantially the same as or slightly larger than the volume space 114, such that unless the volume space 114 is altered (e.g., using the movable wall 112, the controllable expansion element 196, etc.), the inflation medium 130 applies a positive pressure to the composite structure 200 when expanded to the predetermined volume 132. Generally, the amount (e.g., volume) of uninflated inflation medium 130 filled within volume space 114 of restraint container 102 is set by tests or models that predict the pressure within the restraint volume during and after inflation of the inflation medium.

[0070] 1 and 5-8, in one or more embodiments, the expandable medium 130 includes expandable pellets 136. The expandable pellets 136 are thermally activated at an activation temperature 152. In such embodiments, the expandable pellets 136 are configured to expand when the temperature of the expandable pellets 136 is raised to at least the activation temperature 152.

[0071] In one or more embodiments, any suitable number of expandable pellets 136 may be disposed within the volume 114 of the containment container 102, provided that, upon expansion, the expandable pellets exert a positive pressure on the composite surface 206 of the composite structure 200 sufficient to compact and shape the curing composite structure 200. The number of expandable pellets 136 depends on the size of the volume 114. That is, if the containment container 102 closely conforms to the contours of the composite structure 200, fewer expandable pellets 136 may be required. In various embodiments, each expandable pellet 136 may have any suitable dimensions. In one or more embodiments, the length of the expandable pellets 136 is less than about 1 centimeter. The expandable pellets 136 may be substantially uniform in size or may include pellets of different sizes.

[0072] In one or more embodiments, the activation temperature 152 of the expandable pellets 136 is lower than, the same as, or higher than the curing temperature 212 of the composite structure 200. In one or more embodiments, the activation temperature 152 of the expandable pellets 136 is up to or higher than the curing temperature 212 of at least some of the composite plies 208 that form the composite structure 200.

[0073] 1 , in one or more embodiments, the expandable pellets 136 include foamable pellets 138. In one or more embodiments, the expandable pellets 138 are configured to expand when heated to at least a predetermined foaming temperature. In one or more embodiments, the expandable pellets 138 include a foamable material, such as a thermoplastic material treated with a foaming agent, a gas-filled balloon, hollow microspheres, a metal, any other suitable component configured to expand when heated, or any combination thereof.

[0074] 1 , in one or more embodiments, the expandable medium 130 includes an encapsulation element 154. In such embodiments, the expandable pellets 136 are disposed within the encapsulation element 154. In such embodiments, the expandable medium 130 (e.g., the expandable pellets 136) are encapsulated within the encapsulation element 154, which facilitates handling of the expandable medium 130 and facilitates removal of the expandable medium 130 after curing is complete. In one or more embodiments, the encapsulation element 154 is non-expandable. In one or more embodiments, the encapsulation element 154 is expandable.

[0075] In one or more embodiments, the heater 158 is thermally coupled to the expandable medium 130. The heater 158 is configured to heat the expandable medium 130 to an activation temperature 152 at which the expandable medium 130 expands within the volume 114 and applies a positive pressure to the composite structure 200. In one or more embodiments, the heater 158 is an internal heater and is configured to be disposed within the volume 114 of the restraint container 102 along with the expandable medium 130. In one or more embodiments, the heater 158 is an external heater and is configured to be disposed externally of the restraint container 102. The heater 158 may take any suitable form or include any suitable heating device. In various embodiments in which the expandable medium 130 is heat-activated for expansion, at least the restraint container 102, including the cover 106, may be heated externally. Alternatively or additionally, the system 100 may include one or more heat generating materials configured to heat the expansion medium 130 to a predetermined temperature at which the expansion medium 130 expands.

[0076] In various illustrative embodiments, the restraint container 102 includes multiple components, including a base 104 and a cover 106. In one or more embodiments, at least a portion of the composite structure 200 (e.g., portion 202) is disposed on or supported by the base 104 or other rigid support stiffener. In other embodiments, the composite structure 200 is supported by another type of structure, such as another lower part of the composite structure 200. In one or more embodiments, the cover 106 is selectively positioned relative to the composite structure 200 to encapsulate at least the portion 202 to be cured. In one or more embodiments, the cover 106 is disposed on or over the composite structure 200 such that the portion 202 of the composite structure 200 is located within the volume 114 of the restraint container 102. The expansion medium 130 is disposed in (e.g., added to or located within) the volume space 114 of the restraint container 102 so that the expansion medium 130 is adjacent to at least a portion 202 of the composite structure 200 (e.g., an uncured portion, a partially cured portion, a repaired portion) and is located opposite the base 104 or other supporting reinforcement.

[0077] Prior to the curing process, the expansion medium 130 is in an unexpanded state (e.g., FIG. 4). The unexpanded expansion medium 130 may be described as unexpanded or referred to as a non-expandable element. During the curing process, the expansion medium 130 is expanded to an expanded state (e.g., FIG. 5). The expanded expansion medium 130 may be described as expanded or referred to as an expansion element. In the expanded state, the expansion medium 130 applies pressure to the interior surface of the containment container 102 (e.g., cover 106) and the composite surface 206 of at least the portion 202 of the composite structure 200 (e.g., an uncured composite workpiece). The expanded expansion medium 130 applies a positive pressure (created by the expansion of the expansion medium 130) to the composite structure 200 during part or all of the curing process, promoting consolidation. After the composite structure 200 has cured, the expandable medium 130 may be removed from the restraint container 102 before, at the same time as, or after the cured composite structure 200 is removed from the restraint container 102 .

[0078] For purposes of this disclosure, the terms "expandable," "expand," "expanding," and similar terms refer to having the ability to expand or the possibility or capability to increase in size and / or volume. Expansive materials or individual elements can, for example, increase in size or volume symmetrically or asymmetrically. For expandable materials capable of symmetric expansion, the material expands to a substantially equal extent along each axis. For expandable materials exhibiting asymmetric expansion, the material expands relatively more along a first axis, or along both a first and a second axis, than along another axis.

[0079] In various embodiments, the use of a restraining container 102 to apply pressure to an uncured composite workpiece allows for composite production without the use of an industrial autoclave. By employing a restraining container 102 that is smaller than the entire composite structure 200 (e.g., an uncured or partially cured composite structure), the footprint required for curing can be significantly reduced, the amount of intumescent medium 130 can be minimized, and individual portions of the composite structure 200 can be cured locally outside of an autoclave. By employing a restraining container 102 with a selectively controllable volume, for example, by selectively moving one or more of the walls 112 of the cover 106, the amount of intumescent medium 130 required for curing can be significantly reduced.

[0080] In various embodiments, the expansion medium 130 is configured to expand when a predetermined change occurs in the expansion medium 130. The predetermined change is typically a change in a physical or chemical property, or a combination thereof, and / or any other suitable property of the expansion medium 130 associated with the expansion of the expansion medium 130. Unless otherwise specified, expansion of the expansion medium 130 refers to an increase in the volume of the expansion medium 130, the surface area of ​​the expansion medium 130, and / or the spatial extent of the expansion medium 130 in one or more dimensions. As an example, the expansion medium 130 can be configured to expand when the temperature of the expansion medium 130 is increased from a low temperature, such as ambient temperature, to a predetermined elevated temperature. Thus, when curing the composite structure 200 includes increasing the temperature of the composite structure 200, the expansion medium 130 expands within the volume space 114 during the curing process. During the curing process, the expansion medium 130 (eg, during or after expansion) exerts pressure on the uncured portions of the composite structure 200 as well as the interior of the restraint container 102 .

[0081] In various embodiments, the expansion medium 130 is selected so that, upon expansion within the volume 114 of the containment container 102, the expansion medium 130 exerts a pressure sufficient to effectively consolidate the composite material being cured. Some composite materials may be sufficiently compressed and cured at pressures less than 1 atmosphere, while other composite materials may require pressures greater than 1 atmosphere for more effective curing. The expansion medium 130 may be selected to exert pressures sufficient to achieve pressures that would typically require an autoclave in the past (e.g., 1-5 atmospheres).

[0082] In various embodiments, the curing process is simplified and facilitated by adding a plurality of expandable pellets 136 (also referred to as expandable beads) as the expandable medium 130. In such embodiments, the expandable pellets 136 are configured to expand in volume when heated to at least a predetermined temperature. In one or more embodiments, the expandable medium 130 includes one or more different types of expandable pellets 136, each of which is configured to expand (e.g., expand to a predetermined volume) when heated to a predetermined temperature. As an example, the composition of the expandable pellets 136 can be designed to establish a desired relationship between the volume of each expandable pellet 136 and the temperature of the expandable pellet 136 as a function of time.

[0083] In various embodiments, the degree of expansion of a given type or composition of expandable medium 130 (e.g., expandable pellets 136) can be measured and recorded, as can the force generated by the expansion. Thus, the formulation of the composition can be modified to achieve a desired degree of expansion and force. In this manner, the number and composition of expandable pellets 136 employed can be selected so that expansion of multiple expandable pellets 136 within a known volume exerts a desired pressure on the uncured composite workpiece during one or more stages of the curing process. After the composite workpiece has cured, the expanded pellets 136 can be easily removed from the restraining container 102.

[0084] In one or more embodiments, the system 100 includes additional elements configured to modify or adjust the pressure exerted by the expansion medium 130. Such elements may include, for example, but are not limited to, one or more volume-invariant elements 172 (e.g., substantially incompressible elements) and / or one or more contractible elements 174 (e.g., fluid-filled bladders) that can reduce in volume after curing to facilitate access to the composite structure 200.

[0085] In one or more embodiments, the system 100 can also include one or more inflatable elements 196 ( FIG. 1 ). In such embodiments, the inflatable element 196 is disposed within the volumetric space 114 of the restraint container 102. In one or more embodiments, the inflatable element 196 is configured to selectively expand and contract to selectively reduce or increase the volumetric space 114 of the restraint container 102 that is filled with the expansion medium 130 upon expansion. In one or more embodiments, the inflatable element 196 includes or takes the form of a bladder or balloon that contains some type of expansion medium (e.g., expansion medium 130). As an example, a chemical (e.g., baking soda powder) can be placed within the balloon. When the chemical is heated to generate gas, the balloon expands to reduce the fillable volume of the volumetric space 114 of the restraint container 102 and / or to provide a positive pressure to the restraint space. In other embodiments, the inflatable element 196 is an example of the expansion medium 130.

[0086] 3-11 illustrate an embodiment of a workpiece assembly 250 including a composite workpiece 210, such as a composite structure 200, and a restraint container 102. The composite structure 200 is disposed within the restraint container 102. The restraint container 102 is configured to encapsulate at least a portion 202 of the composite structure 200 to be cured. In one embodiment, at least the portion 202 of the composite structure 200 to be cured is covered or otherwise encapsulated by a cover 106. The cover 106 is configured to facilitate application of pressure to a composite surface 206 of the composite structure 200 by expansion of an expandable medium 130. In one or more embodiments, the composite structure 200 is disposed on a base 104 or, if desired, is supported by the cover 106 and stiffeners on a side opposite the direction of positive pressure. In one or more embodiments, a wall 112 of the cover 106 defines a volume 114 within the restraint container 102.

[0087] The inflation medium 130 is added to the volume 114. An appropriate amount of inflation medium 130 is used so that during and / or after inflation, the inflation medium 130 contacts the composite structure 200 and the inner surface of the cover 106 to generate a positive pressure that acts on the composite surface 206 of the composite structure 200.

[0088] The expansion medium 130 can take any suitable form. In one or more embodiments, the expansion medium 130 is added to the restraining container 102 as, for example, pellets, beads, particles, powder, or foam. Alternatively or additionally, the expansion medium 130 is added to the restraining container 102 as a solid or semi-solid discrete portion, such as a layer of expansion medium 130 that can be applied over the entire portion 202 of the composite structure 200. The layer of expansion medium 130 can be added by placing a separate containment element 154 (e.g., a pouch or bag) filled with pellets, beads, or other smaller pieces of expansion medium 130. While FIGS. 4 and 5 depict a plurality of expansion pellets 136 as the expansion medium 130, this is representative and should not be construed as limiting the structure or configuration of the expansion medium 130.

[0089] In various embodiments, the expansion medium 130 is added in an unexpanded state to the volume space 114 of the restraining container 102. As shown in Figure 5, the expansion medium 130 is expanded (e.g., increases in volume) prior to and / or during the curing process to at least partially fill the volume space 114, such that the expansion medium 130 (in its expanded state) directly or indirectly applies positive pressure to at least some of the interior surfaces of the cover 106 and the composite surfaces 206 (e.g., the top and / or outer surfaces) of the composite structure 200. The pressure created by the expansion of the expansion medium 130 promotes compression and consolidation of the portions 202 of the composite structure 200 as they cure.

[0090] In various embodiments, the expansion medium 130 is configured to expand (to a predetermined volume and / or pressure) when a predetermined change occurs in a property 134 of the expansion medium 130 (e.g., in an unexpanded state). In one or more embodiments, the expansion medium 130 is added (e.g., inserted or dropped) into the volume space 114 of the restraint container 102 in an unexpanded state. The predetermined change in the property 134 of the unexpanded expansion medium 130 occurs while the expansion medium 130 is within the volume space 114 in an unexpanded state. The expansion medium 130 expands in response to the predetermined change. The property 134 of the expansion medium 130 can be a physical and / or chemical property.

[0091] In one or more embodiments, the expansion medium 130 is configured to expand in volume upon interaction with water. By way of example, the expansion medium 130 is or includes a desiccant, which may increase in volume upon absorbing water. For example, anhydrous calcium sulfate (anhydrite) increases in volume by approximately 61% upon absorbing water to form gypsum. In such embodiments, water may be added directly to the expansion medium 130, such as by adding liquid water or steam to the interior of the containment container 102. Alternatively or additionally, water or steam may be generated within the containment container 102 itself, such as by a suitable chemical reaction.

[0092] In one or more embodiments, the predetermined change in the attribute 134 of the expansion medium 130 includes a change in the temperature of the expansion medium 130 and / or a change in the temperature of one or more portions of the expansion medium 130. Thus, causing the predetermined change in the attribute of the expansion medium 130 can include raising the temperature of the unexpanded expansion element from a low temperature, such as an ambient temperature (e.g., room temperature), to at least an initial temperature or a predetermined temperature above ambient temperature (e.g., the predetermined temperature is a few degrees above ambient temperature suitable to cause the predetermined expansion of the expansion element). The expansion element undergoes thermal expansion as a result of this temperature increase.

[0093] In one or more embodiments, the expansion medium 130 is a heat-activated expansion element. In such embodiments, the heat-activated expansion element is configured to expand when the temperature of the expansion medium 130 increases to at least a predetermined temperature. Alternatively or additionally, by heating and expanding the expansion medium 130 to at least a predetermined temperature, the expansion medium 130 generates a predetermined pressure acting on the composite structure 200. Typically, the predetermined pressure is sufficient to sufficiently cure the composite material.

[0094] In one or more embodiments, the predetermined change that occurs in the attribute 134 of the expansion medium 130 is a combination of two or more properties of the expansion medium 130, for example, a ratio or product of quantitative values ​​related to the properties of the expansion medium 130, such as two materials with different thermal expansion coefficients.

[0095] In various embodiments, the process of curing the composite structure 200 includes causing a predetermined change in a property 134 of the expandable medium 130. In one or more embodiments, the expansion of the expandable medium 130 occurs automatically during the curing process. For example, the property 134 may be the temperature of the expandable medium 130, and the application of heat to the workpiece assembly 250 during the curing process may cause a predetermined change in the temperature of the expandable medium 130. That is, the application of heat to the workpiece assembly 250 during the curing process may increase the temperature of the expandable medium 130 to at least a predetermined temperature associated with a desired volume and / or volumetric increase. One or more properties of the expandable medium 130 may be configured such that the temperature change experienced by the expandable medium 130 during curing of the composite structure 200 causes the expandable medium 130 to thermally expand to a predetermined desired amount of expansion. Alternatively or additionally, expansion of the expandable medium 130 may require additional steps beyond those required to cure the composite structure 200. By way of example, expanding the expansion medium 130 can include applying an electric field, injecting a liquid, gas, and / or other suitable material, and / or causing any other suitable change to the expansion medium 130.

[0096] In various embodiments, the expandable medium 130 includes any material that is thermally expandable and expands when it reaches a predetermined temperature. As a specific example, a group of plastic polymers that soften when heated are referred to as thermoplastic materials. When a solid thermoplastic material is heated above its glass transition temperature but below its melting point, it softens and becomes a viscous liquid. In this state, the thermoplastic material is reshapeable, and more specifically, expandable.

[0097] Various types of thermoplastic materials are known, including, for example, acrylic polymers, acrylonitrile butadiene styrene (ABS) polymers, nylon polymers, polylactic acid (PLA) polymers, polybenzimidazole polymers, polycarbonate polymers, polyethersulfone (PES) polymers, polyetherimide (PEI) polymers, polyethylene (PE) polymers, polyphenylene oxide (PPO) polymers, polyphenylene sulfide (PPS) polymers, polyvinyl chloride (PVC) polymers, polyvinylidene fluoride (PVDF) polymers, polytetrafluoroethylene (PTFE) polymers, etc. In particular, an expandable medium 130 comprising acrylonitrile butadiene styrene (ABS) polymers can exhibit advantageous physical properties when used in combination with the embodiments described herein.

[0098] In one or more embodiments, the expandable medium 130 (e.g., expandable pellets 136) can further include a foaming agent. The foaming agent is selected to form a plurality of holes, pockets, or voids within the material of the expandable medium 130 when heated to at least a predetermined temperature, thereby increasing the volume of the expandable medium 130. By way of example, a suitable foaming agent can be an inert gas impregnated into the expandable medium 130 under pressure. Such a foaming agent can be configured to expand at a plurality of locations within the expandable medium 130 when the temperature of the expandable medium 130 is increased from an ambient or initial temperature to a predetermined elevated temperature, with the expanded gas forming holes, pockets, or voids within the pellets. If a foaming agent is used, it can be added to the expandable medium 130 prior to heating.

[0099] In embodiments in which the expansion medium 130 includes a blowing agent, the blowing agent can be any suitable substance capable of producing the desired degree of expansion. Examples of blowing agents include physical blowing agents such as chlorofluorocarbons, hydrochlorofluorocarbons, hydrocarbons, and liquid CO2. Alternatively or additionally, the blowing agent can include chemical blowing agents selected to react with one or more components of the expansion medium 130, such as isocyanates and water for polyurethanes, azodicarbonamide for vinyls, hydrazine and other nitrogen-based materials for thermoplastic and elastomeric foams, and sodium bicarbonate for thermoplastic foams.

[0100] In embodiments in which the expandable medium 130 includes a foaming agent, the foaming agent may include a foaming agent. In such embodiments, the foaming agent may be selected to generate gas, and the foaming agent may be a material that promotes foam formation, such as a surfactant. Suitable foaming agents include, for example, sodium laureth sulfate, sodium lauryl ether sulfate (SLES), sodium lauryl sulfate (also known as sodium dodecyl sulfate or SDS), ammonium lauryl sulfate (ALS), and the like.

[0101] During the process of curing the composite structure 200, the expandable medium 130 (e.g., expandable pellets 136) is changed from an unexpanded state ( FIG. 4 ) to an expanded state ( FIG. 5 ). In one or more embodiments, the expandable pellets 136 are configured to expand in response to heat applied to the workpiece assembly 250 during curing. The expandable pellets 136 expand to fill the volume space 114 of the cover 106, whereby the expanded expandable pellets 136 apply a positive pressure to the composite structure 200, causing it to cure.

[0102] In one or more embodiments, the expandable medium 130 (e.g., expandable pellets 136) is configured (e.g., formulated) to be at least partially deformable after, during, and / or before expansion. Having some degree of deformability allows the expandable medium 130 to fill small gaps that exist, such as between pellets, between the pellets and the inner surface of the cover 106, and / or between the pellets and the composite surface 206 of the composite structure 200. The expandable medium 130 can fill these gaps, thereby providing a substantially smooth surface for the composite structure 200.

[0103] In various embodiments, after the portion 202 of the composite structure 200 has cured, the cover 106 can be unsealed, opened, or removed as needed, thereby allowing the expansion medium 130 to be removed. While the expansion medium 130 is generally easily removed after the composite structure 200 has cured, in some cases the expansion medium 130 may remain expanded and tightly packed after the composite structure 200 has cured and cooled, which tends to impede removal. In such cases, the expansion medium 130 may be further configured in one or more ways to be more easily separated from the composite structure 200, the base 104, and / or the cover 106. As one example, the expansion pellets 136 may be configured to change shape and / or size as needed, thereby facilitating removal. For example, the expandable pellets 136 can be configured to shrink when cooled, thereby allowing the expandable pellets 136 to shrink within the volume space 114 after the composite structure 200 has hardened and cooled, facilitating removal of the expandable pellets.

[0104] In one or more embodiments, the expandable medium 130 is modified to minimize sintering (self-adhesion) upon heating and expansion. Alternatively or additionally, the expandable medium 130 is configured to minimize the possibility of adhesion to surfaces, such as by coating the expandable pellets 136 with an agent suitable for preventing adhesion and / or promoting separation.

[0105] In one or more embodiments, suitable agents for addition to the expandable medium 130 include lubricants. As an example, a lubricant can be added to the expandable pellets 136 before and / or after volumetric expansion to inhibit adhesion between the expandable pellets 136. A suitable lubricant does not interfere with the hardening of the composite structure 200 and prevents the expanded pellets 136 from substantially adhering to each other, to the containment container 102, or to components of the workpiece assembly 250. Suitable lubricants may include liquids, powders, or combinations thereof. If added as a powder, suitable lubricants may include nanopowder. Alternatively or additionally, suitable lubricants may include silicone-based materials, fluorinated polymers, or other substantially inert substances. For example, suitable lubricants may include polytetrafluoroethylene (PTFE) powder, PTFE nanopowder, silicone, perfluoropolyether (PFPE), perfluoroalkyl ether (PFAE), perfluoropolyalkyl ether (PFPAE), etc. Such a lubricant may be added to the expandable pellets 136 before the expandable pellets 136 are placed in the containment container 102. Alternatively or additionally, a suitable lubricant may be added to the expandable pellets 136 while they are disposed in the containment container 102. Coating at least some of the expandable pellets 136 with a suitable lubricant may include mixing the lubricant with the plurality of pellets and / or pouring the lubricant over the plurality of pellets. Additionally or alternatively, at least some of the plurality of expandable pellets 136 may be coated with a desired lubricant before being mixed with the plurality of uncoated pellets.

[0106] In one or more embodiments, crystallinity and / or semi-crystallinity in the outer surfaces of the expandable pellets 136 can be utilized to prevent the pellets from sintering together. In one or more embodiments, at least some of the expandable pellets 136 are configured, such as by pre-processing, to have crystalline regions along their outer surfaces. Thus, adding the expandable medium 130 can include adding multiple expandable pellets 136 having surface regions with increased crystallinity to reduce adhesion between the expandable pellets 136 before and / or after volumetric expansion of the expandable pellets 136. In one or more embodiments, the expandable pellets 136 can have a highly crystalline outer surface (e.g., a large proportion of the volume of the region near the outer surface of each pellet is crystalline). Such crystallinity can be induced in the expandable pellets 136 by controlling one or more factors, including the material composition of the pellets, the manufacturing temperature to which the pellets are heated during manufacturing, the time the pellets are maintained at the manufacturing temperature during manufacturing, the electric and / or magnetic fields applied during manufacturing, the distribution of the blowing agent in the pellets, and the composition and / or concentration of the blowing agent. The crystallization of the outer surface of the expandable pellets 136 may occur before, during, and / or after foaming.

[0107] 2 illustrates one or more embodiments of method 1000. An embodiment of method 1000 according to the present disclosure is described below. Method 1000 includes multiple elements, steps, operations, or processes. Not all of the elements, steps, operations, or processes described or illustrated in one embodiment are required for that embodiment. Some or all of the elements, steps, operations, or processes described or illustrated in one embodiment can be combined in various ways with other embodiments without including other elements, steps, operations, or processes described in those other embodiments, even if not explicitly described or illustrated by the embodiment herein.

[0108] 1 and 3-11, and particularly FIG. 2, in various embodiments, method 1000 includes multiple steps, as described in more detail later herein. In one or more embodiments, method 1000 is implemented using system 100 (FIG. 1).

[0109] In one or more embodiments, according to method 1000, composite structure 200 includes a plurality of composite plies 208. In one or more embodiments, at least a portion of composite plies 208 are in an uncured state. In one or more embodiments, at least a portion of composite plies 208 are in a partially cured state. In one or more embodiments, at least a portion of composite plies 208 are in need of repair or are in the form of a repair patch (e.g., composite patch 214). In one or more embodiments, at least one of composite plies 208 is a composite patch 214 configured to repair a portion of composite surface 206 of composite structure 200.

[0110] In one or more embodiments, the method 1000 includes supporting 1002 at least the portion of the composite structure 200 on a base 104 of the restraint container 102. In one or more embodiments, at least the portion 202 of the composite structure 200 to be cured is supported by the base 104 such that the base 104 reinforces the composite structure 200 during the curing process.

[0111] In one or more embodiments, the method 1000 includes a step 1004 of disposing a casting 156. In one or more embodiments, the casting 156 is placed or disposed between the expandable medium 130 and the composite surface 206 of the composite structure 200. The method 1000 includes a step 1006 of solidifying the casting 156. In such embodiments, the casting 156 is disposed on the composite surface 206 of at least the portion 202 of the composite structure 200.

[0112] In one or more embodiments, the method 1000 includes moving 1008 the cover 106 relative to the composite structure 200. The cover 106 is moved into a suitable position to cover and encapsulate at least the portion 202 of the composite structure 200 to be cured using the system 100.

[0113] In one or more embodiments, the method 1000 includes enclosing 1010 at least the portion 202 of the composite structure 200 to be cured in the restraint container 102. As an example, the cover 106 is positioned relative to the composite structure 200 such that at least the portion 202 of the composite structure 200 is enclosed within the volume space 114 of the restraint container 102 (e.g., the cover 106).

[0114] In one or more embodiments, the method 1000 includes step 1012 of holding the cover 106 against the composite structure 200. In one or more embodiments, the cover 106 is held against the composite structure 200 using a retention mechanism 120.

[0115] In one or more embodiments, the method 1000 includes the step 1014 of coupling the cover 106 to the base 104. In one or more embodiments, the cover 106 and the base 104 are coupled using a retention mechanism 120.

[0116] In one or more embodiments, the method 1000 includes a step 1016 of adding an expandable medium 130. In one or more embodiments, the expandable medium 130 is added to the volume 114 inside the cover 106. In one or more embodiments, the adding step 1016 occurs before the encapsulating step 1010. In one or more embodiments, the adding step 1016 occurs after the encapsulating step 1010.

[0117] In one or more embodiments, the method 1000 includes selectively altering 1018 the volume 114 formed by the restraint container 102 and the composite structure 200. In one or more embodiments, the volume 114 is selectively altered by moving at least one of the walls 112 of the cover 106. As an example, selectively altering 1018 the volume 114 of the restraint container 102 includes moving at least one of the walls 112 relative to at least one other of the walls 112.

[0118] In one or more embodiments, the method 1000 includes altering 1020 an attribute 134 of the expansion medium 130 to expand the expansion medium 130 to a predetermined volume 132. In one or more embodiments, the method 1000, e.g., altering 1020 an attribute 134 of the expansion medium 130, includes increasing the temperature of the expansion medium 130 to at least an activation temperature 152.

[0119] In one or more embodiments, the method 1000 includes a step 1022 of inflating the expandable medium 130 disposed in the volume 114. In one or more embodiments, the volume 114 is defined by the wall 112 of the cover 106 and the composite structure 200. In one or more embodiments, the volume 114 is defined by the wall 112 of the cover 106, the composite structure 200, and the base 104. In one or more embodiments, the volume 114 is divided into an expansion chamber 192 and a pressure chamber 194.

[0120] In one or more embodiments, the method 1000 includes applying 1024 a positive pressure to the composite structure 200. As the expandable medium 130 expands, it fills the volume space 114 and applies a positive pressure to the composite structure 200 and the cover 106.

[0121] In one or more embodiments, the method 1000 includes detecting 1026 a pressure and / or force acting on the composite structure 200 due to the expansion of the expandable medium 130. In one or more embodiments, the pressure and / or force is detected using a sensor 166. In one or more embodiments, the method 1000 includes selectively controlling 1028 the pressure and / or force acting on the composite structure 200.

[0122] In one or more embodiments, the method 1000 includes curing 1030 at least the portion 202 of the composite structure 200. The composite structure 200 is cured by pressure exerted by the expanding expandable medium 130 within the volume 114. In one or more embodiments, the composite structure 200 is also cured by heating.

[0123] In one or more embodiments, the method 1000 includes a step 1032 of removing the inflation medium 130. In one or more embodiments, the method 1000 includes a step 1034 of removing the cover 106 and other components of the restraint container 102.

[0124] Referring again to FIGS. 1 and 3-11, an example of a composite workpiece 210 according to the present disclosure is described below. The composite workpiece 210 includes a number of elements, features, and components. Not all of the elements, features, and / or components described or illustrated in one example are required for that example. Some or all of the elements, features, and / or components described or illustrated in one example can be combined in various ways with other examples without including other elements, features, and / or components described in those other examples, even if not explicitly described or illustrated by the example herein.

[0125] In one or more embodiments, the composite workpiece 210 includes a composite structure 200 including multiple composite layers 208. At least a portion 202 (e.g., at least one of the composite layers 208) is uncured, partially cured, or in need of repair. At least a portion 202 of the composite structure 200 is supported by a base 104 of a restraint container 102. At least a portion 202 of the composite structure 200 is enclosed by a cover 106 of the restraint container 102. In one or more embodiments, the cover 106 includes multiple walls 112 that define at least a portion of a volume 114. At least one of the walls 112 is movable relative to at least one other of the walls 112 to selectively change the volume 114. An expandable medium 130 is disposed between the cover 106 and the composite structure 200 in the volume 114 of the cover 106. The expansion medium 130 is configured to expand to a predetermined volume 132 when a predetermined change occurs in a property 134 of the expansion medium 130, thereby applying a positive pressure to the composite structure 200 and the cover 106.

[0126] In one or more embodiments of composite workpiece 210, at least one of composite plies 208 is a composite patch 214. Composite patch 214 is configured to be cured using system 100 to repair a portion of composite surface 206 of composite structure 200.

[0127] In one or more embodiments, the expandable medium 130 includes expandable pellets 136. The expandable pellets 136 are heat activated at an activation temperature 152. The activation temperature 152 of the expandable pellets 136 is lower than, at least equal to, or higher than the curing temperature 212 of the plurality of composite layers 208.

[0128] In various other embodiments of the composite workpiece 210, the system 100 includes any one or more of the components described herein and / or illustrated in Figures 1 and 3-11.

[0129] Embodiments of the disclosed system 100 and method 1000 are useful for a variety of composite materials and for producing desired parts for any suitable industrial application. The system 100 and method embodiments described herein are particularly useful for producing out-of-autoclave composites, such as may be desired in a manufacturing environment or at a remote job site. The system 100 and method 1000 embodiments described herein are also useful for producing parts with unique or complex shapes that cannot be easily processed in an industrial autoclave.

[0130] 14 and 15, embodiments of the system 100 and method 1000 described herein may be associated with or may be used in association with an aerospace manufacturing and service method 1100, as illustrated in the flowchart of Figure 14, and an aircraft 1200, as illustrated generally in Figure 15. By way of example, the aircraft 1200 and / or the manufacturing and service method 1100 may include or utilize composite parts that have been cured or repaired using the system 100 and / or according to the method 1000.

[0131] Embodiments of the system 100 and method 1000 disclosed herein may be used in any suitable industry to manufacture any desired composite material, and although the embodiments presented herein are described in the context of aircraft manufacturing and service, these are merely examples and should not be construed as limiting the applicability of the disclosed systems and methods.

[0132] Referring to FIG. 15 , an example of an aircraft 1200 is shown. The aircraft 1200 may be any aerospace vehicle or platform. In one or more embodiments, the aircraft 1200 includes an airframe 1202 having an interior 1206. The aircraft 1200 includes multiple onboard systems 1204 (e.g., high-level systems). Examples of the onboard systems 1204 of the aircraft 1200 include a propulsion system 1208, a hydraulic system 1212, an electrical system 1210, and an environmental system 1214. In other examples, the onboard systems 1204 also include one or more control systems coupled to the airframe 1202 of the aircraft 1200. In still other examples, the onboard systems 1204 also include one or more other systems, such as, but not limited to, a communications system, an avionics system, a software distribution system, a network communications system, a passenger information / entertainment system, a guidance system, a radar system, a weapons system, etc. Each system may include various subsystems such as controllers, processors, actuators, effectors, motors, generators, etc. depending on the functionality involved.

[0133] Aircraft 1200 may have any number of composite structures, at least a portion of which may be locally stiffened using system 100 and / or according to method 1000. Any component or substructure of an aircraft suitable for composite manufacturing may be adapted for the exemplary methods and processes described herein, including, but not limited to, structural components, fuselage panels, bulkhead sections, etc. As an example, system 100 and method 1000 described herein are particularly useful for manufacturing and / or repairing stiffeners or stringers used in aircraft manufacturing.

[0134] 12 and 13 , in one or more embodiments, the aircraft 1200 includes one or more stiffeners 220 configured to support a load. In some embodiments, the stiffeners 220 are attached to the skin panels 222 to improve the strength, rigidity, and / or buckling resistance of the skin panels 222. The stiffeners 220 may be included in any suitable portion of the frame of the aircraft (e.g., the airframe 1202) and / or any other suitable portion of the aircraft 1200. FIGS. 12 and 13 illustrate stiffeners 220 stiffening the skin panels 222, such as in the example of the wings 224 of the aircraft 1200.

[0135] 12 illustrates an example composite structure 200 in the form of a hat-shaped composite stiffener (e.g., stiffener 220). In one or more embodiments, stiffener 220 includes a cap portion 232 and a first sidewall 234 and a second sidewall 236 extending from opposite sides of cap portion 232. In an exemplary embodiment, first sidewall 234 and second sidewall 236 form an obtuse angle with cap portion 232. In other embodiments, first sidewall 234 and second sidewall 236 can form an acute angle or a substantially right angle with cap portion 232. The angle between cap portion 232 and first sidewall 234 may or may not be equal to the angle between cap portion 232 and second sidewall 236. Cap portion 232 may be substantially planar or may include curved and / or angled portions. The stiffener 220 further includes a first flange 238 extending from the first side wall 234 and a second flange 242 extending from the second side wall 236. The first flange 238 and the second flange 242 extend in opposite directions away from each other and may be parallel to the cap portion 232 (e.g., the first flange and the second flange may be coplanar and define a plane generally parallel to a plane defined by the cap). The first flange 238 and the second flange 242 each have a bottom surface attachable to the skin 222, and the stiffener 220 is configured to reinforce, stiffen, and strengthen the skin 222 through the bottom surfaces. Multiple stiffeners 220 can be used to attach to a wide area of ​​the skin 222.

[0136] 13 shows an example composite structure 200 in the form of a wing 224 of an aircraft 1200. In various embodiments, stiffener 220 is attached to skin 222 either by holding stiffener 220 and skin 222 together while curing, or by separately curing stiffener 220 and skin 222 and then fastening stiffener 220 to skin 222. In various embodiments, stiffener 220 and skin 222 can each comprise one or more polymeric materials, thermoplastic materials, thermoset materials, fiber-reinforced materials, and / or other suitable materials, depending on the properties desired for the finished workpiece.

[0137] For example, composite stiffeners and stringers are often placed on fuselage sections and wing skins to provide added stiffness and strength to the aircraft panels to which they are attached while saving weight. Stiffeners may have concave cross-sections with protruding extensions to provide added strength and rigidity. Stiffeners may also have an overall curved shape to match the curvature of the fuselage to which they are attached. Stiffeners may also include one or more bends or joggles to accommodate one or more aircraft systems. Due to these constraints, stiffeners may have sizes and shapes that make them difficult to transport in and out of industrial autoclaves, and in some cases, the autoclave may not accommodate the uncured stiffeners. However, such composite stiffeners can be easily accommodated in a restraint container 102 specifically sized and shaped to fit the stiffener and the localized area of ​​the stiffener. A composite stiffener in an uncured, partially cured, or repaired state can be placed on a rigid mold (e.g., base 104) configured to define and incorporate the stiffener's desired cross-sectional profile, desired curvature, and desired step bend. The composite stiffener can then be easily cured while positioned on the rigid mold by applying the required pressure to the composite with an appropriate inflatable element (e.g., inflatable medium 130). Similarly, areas on composite panels forming the fuselage and / or wings may also require repair. In such cases, it may be difficult to accommodate these repairs in an autoclave. However, such composite panels can be easily accommodated in a restraining container 102 that can be easily moved to cure the repaired areas of the fuselage or wing.

[0138] 14 , prior to the start of production of the aircraft 1200, manufacturing and service method 1100 includes specification and design 1102 of the aircraft 1200 and material procurement 1104. During production of the aircraft 1200, component and subassembly manufacturing 1106 and system integration 1108 of the aircraft 1200 occur. The aircraft 1200 then undergoes certification and delivery 1110 and enters service 1112. Routine maintenance and service 1114 includes upgrading, reconfiguring, modifying, etc., one or more systems of the aircraft 1200.

[0139] 14 may be performed or implemented by a system integrator, a third party, and / or an operator (e.g., a customer). A system integrator may include, but is not limited to, any number of aircraft manufacturers and major system subcontractors. A third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers. An operator may include, but is not limited to, an airline, a leasing company, a military entity, a service organization, and the like.

[0140] Embodiments of the system 100 and method 1000 shown and described herein may be employed during one or more of the steps of the manufacturing and service method 1100 illustrated in the flowchart of FIG. 14 . In one example, at least a portion of a composite structure may be cured using the system 100 and / or according to the method 1000 during part and subassembly manufacturing 1106 and / or as part of system integration 1108. Additionally, at least a portion of a composite structure may be locally cured using the system 100 and / or according to the method 1000 while the aircraft 1200 is in service 1112. Also, at least a portion of a composite structure may be cured using the system 100 and / or according to the method 1000 during system integration 1108 and certification and delivery 1110. Similarly, at least a portion of a composite structure may be cured using the system 100 and / or according to the method 1000 while the aircraft 1200 is in service 1112 and during maintenance and service 1114.

[0141] The foregoing detailed description refers to the accompanying drawings, which illustrate specific embodiments described in the present disclosure. Other embodiments having different structures and operations do not depart from the scope of the present disclosure. Like reference numerals may refer to the same feature, element, or component in different drawings. Throughout this disclosure, any one of multiple elements may be referred to individually, and multiple elements may be referred to collectively and designated by like reference numerals. Furthermore, in this specification, a feature, element, component, or step referred to in the singular does not exclude the plural features, elements, components, or steps, unless expressly stated otherwise.

[0142] Illustrative, non-exhaustive examples of the subject matter of the present disclosure are provided above, including those claimed and those not claimed. As used herein, an "example" means that one or more features, structures, elements, components, features, and / or operational steps described in connection with that example are included in at least one aspect, embodiment, and / or implementation of the subject matter of the present disclosure. Thus, terms such as "one example," "another example," "one or more examples," and similar terms in this disclosure may, but do not necessarily, refer to the same example. Furthermore, features characterizing one example may, but do not necessarily, include features characterizing any other example. Furthermore, features characterizing one example may, but do not necessarily, be combined with features characterizing any other example.

[0143] As used herein, a system, apparatus, device, structure, article, element, component, or hardware that is "configured" to perform a particular function refers to one that can perform that particular function without any modification, and not one that could perform that particular function with any modification. That is, a system, apparatus, device, structure, article, element, component, or hardware that is "configured" to perform a particular function refers to one that is specifically selected, made, implemented, used, programmed, and / or designed to perform that particular function. As used herein, "configured" refers to characteristics that a system, apparatus, structure, article, element, component, or hardware already possesses that enable the system, apparatus, structure, article, element, component, or hardware to perform that particular function without any modification. In this disclosure, a system, apparatus, device, structure, article, element, component, or hardware that is described as "configured" to perform a particular function may also or instead be described as being "adapted" and / or "operable" to perform that function.

[0144] Unless otherwise indicated, the terms "first," "second," "third," etc. are used herein merely as labels and do not impose any order, position, or hierarchy requirements on the elements to which they refer. Furthermore, a reference to, for example, a "second" element does not require or exclude the presence of, for example, a "first" element or a lower ordinal element, and / or a "third" or higher ordinal element.

[0145] As used herein, the phrase "at least one" in reference to a list of elements means that one or more of the listed elements may be used in various combinations, or that only one of the listed elements may be required. For example, "at least one of element A, element B, and element C" includes, but is not limited to, element A, element A and element B. This example also includes elements A, element B, and element C, or elements B and element C. In other examples, "at least one" may mean, but is not limited to, two elements A, one element B, and ten elements C, or four elements B and seven elements C, or other suitable combinations. As used herein, the phrase "and / or" and the symbol " / " include any and all combinations of one or more of the associated listed elements.

[0146] As used herein, the terms "coupled," "couple," and the like refer to two or more elements being joined, linked, fastened, attached, connected, in communication, or otherwise associated (e.g., mechanically, electrically, fluidly, optically, electromagnetically) with one another. In various embodiments, these elements may be directly or indirectly associated. As an example, element A may be directly associated with element B. As another example, element A may be indirectly associated with element B, e.g., through another element C. It should be noted that not all associations between the various elements of this disclosure are necessarily shown. Thus, other connections may exist than those shown.

[0147] As used herein, the term "approximately" refers to a state that is not exactly the same as the described state, but is close to the described state and is capable of performing a desired function or achieving a desired result. As an example, the term "approximately" refers to a state that is within an acceptable predetermined tolerance or precision, for example, within 10% of the described state. However, the term "approximately" does not exclude a state that is exactly the same as the described state. Additionally, as used herein, the term "substantially" refers to a state that is essentially the same as the described state and is capable of performing a desired function or achieving a desired result.

[0148] The figures 1, 3-13, and 15 referenced in the above description depict functional elements, features, or components thereof and do not necessarily imply a specific, concrete structure. Accordingly, modifications, additions, and / or omissions may be made to the depicted structures. Furthermore, those skilled in the art will recognize that not all elements, features, and / or components shown and described in Figures 1, 3-13, and 15 need be present in every embodiment, and not all elements, features, and / or components described herein may be present in each illustrated embodiment. Accordingly, some of the elements, features, and / or components shown and described in Figures 1, 3-13, and 15 may be combined in various ways without including other features shown in Figures 1, 3-13, and 15, other figures, and / or the accompanying disclosure, without such combinations necessarily being explicitly set forth herein. Similarly, additional features not limited to the illustrated embodiments may be combined with some or all of the features shown and described herein. Unless otherwise noted, the schematic diagrams of the above-described embodiments shown in FIGS. 1, 3-13, and 15 are not intended to imply structural limitations on the exemplary embodiments. Rather, they illustrate one exemplary structure, which should be understood as being capable of being varied. Accordingly, modifications, additions, and / or omissions may be made to the depicted structure. Furthermore, elements, features, and / or components serving similar, or at least substantially similar, purposes are labeled with like reference numerals in each of FIGS. 1, 3-13, and 15, and such elements, features, and / or components may not be described in detail herein with reference to FIGS. 1, 3-13, and 15. Similarly, not all elements, features, and / or components may be labeled with reference numerals in each of FIGS. 1, 3-13, and 15, although their associated reference numerals may be used herein for consistency.

[0149] In the above-referenced Figures 2 and 14, the blocks represent, for example, operations, steps, and / or portions thereof, and the lines connecting the various blocks do not imply a particular order or dependency of these operations or portions thereof. It should be noted that not all dependencies between the various operations disclosed are necessarily shown. Figures 2 and 14 and the accompanying disclosure describing operations in the methods described herein do not necessarily dictate the order in which these operations are performed. Rather, while suggesting one exemplary order, it should be understood that the order of these operations may be changed as appropriate. Accordingly, modifications, additions, and / or omissions may be made to the illustrated operations, and some operations may be performed in a different order or simultaneously. Furthermore, one skilled in the art will recognize that not all of the operations described need to be performed.

[0150] Furthermore, references to features, advantages, or similar terms throughout this specification do not imply that all features and advantages that may be realized by the embodiments disclosed herein should or are included in any one embodiment. Rather, a description of features and advantages means that the particular feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment. Thus, references to features, advantages, and similar language used in this disclosure may, but do not necessarily, refer to the same embodiment.

[0151] The described features, advantages, and characteristics of one embodiment may be incorporated in any suitable manner into one or more other embodiments. Those skilled in the art will recognize that the various embodiments described herein can be practiced without one or more of the specific features or advantages of a particular embodiment. Also, in other cases, additional features and advantages may be recognized in a particular embodiment that are not present in all embodiments. Moreover, while various embodiments of system 100 and method 1000 have been shown and described, modifications will occur to those skilled in the art upon reading this specification. The present application includes such modifications and is intended to be limited only by the scope of the claims.

[0152] The present disclosure also includes the following notes:

[0153] Appendix 1. A containment container (102) including a base (104) and a cover (106), the containment container (102) having a volume (114), the containment container (102) configured to enclose at least a portion of a composite structure (200); an expandable medium (130) configured to be disposed in the volume (114) between at least a portion of the containment container (102) and the composite structure (200); A system (100) wherein the volume (114) of the containment container (102) is selectively variable.

[0154] Appendix 2. The system (100) of Appendix 1, wherein the cover (106) of the containment container (102) includes at least one of a plurality of walls (112) and an overlay (168).

[0155] Appendix 3. The system (100) of Appendix 2, further comprising an actuator (108) configured to move at least one of the plurality of walls (112) relative to at least one other of the plurality of walls (112) to selectively change the volume space (114) of the restraint container (102).

[0156] Appendix 4. The system (100) of Appendix 2 or 3, wherein the expandable medium (130) is disposed between at least one of the walls (112) included in the cover (106) and the composite structure (200).

[0157] Note 5: The plurality of walls (112) includes a plurality of side walls (184) and an upper wall (182); 5. The system (100) of any one of claims 2 to 4, wherein the top wall (182) is movable relative to the plurality of side walls (184) to selectively change the volume space (114) of the containment container (102).

[0158] Clause 6. The system (100) of clause 5, further comprising an actuator (108) configured to move the top wall (182) relative to the plurality of side walls (184).

[0159] Clause 7. The system (100) of clause 5 or 6, wherein the expandable medium (130) is disposed between the upper wall (182) and the composite structure (200).

[0160] Appendix 8. A system (100) according to any one of Appendixes 5 to 7, wherein at least one of the plurality of side walls (184) is movable relative to at least one other of the plurality of side walls (184) and relative to the top wall (182) to selectively vary the volume space (114) of the containment container (102).

[0161] Appendix 9. The system (100) of Appendix 8, further comprising a plurality of actuators (108) configured to move the top wall (182) and at least one of the plurality of side walls (184).

[0162] Appendix 10. The system (100) of Appendix 8 or 9, wherein the expandable medium (130) is disposed between the top wall (182) and the composite structure (200) and between at least one of the plurality of side walls (184) and the composite structure (200).

[0163] Appendix 11. A system (100) described in any one of Appendixes 5 to 10, wherein each of the plurality of side walls (184) is movable relative to another one of the plurality of side walls (184) and relative to the top wall (182) to selectively change the volume space (114) of the containment container (102).

[0164] Appendix 12. The system (100) of Appendix 11, further comprising a plurality of actuators (108) configured to move the top wall (182) and each of the plurality of side walls (184).

[0165] Appendix 13. The system (100) of Appendix 11 or 12, wherein the expandable medium (130) is disposed between the top wall (182) and the composite structure (200), and between each of the plurality of side walls (184) and the composite structure (200).

[0166] Note 14. The cover (106) includes a plurality of side walls (184), a top wall (182), and a cap (186); 5. The system (100) of any one of claims 1 to 4, wherein the cap (186) is sealed to the plurality of side walls (184) and is movable relative to the plurality of side walls (184) and the top wall (182) to selectively change the volume space (114) of the containment container (102).

[0167] Clause 15. The system (100) of clause 14, wherein the expandable medium (130) is disposed between the upper wall (182) and the cap (186).

[0168] Appendix 16. The base (104) supports at least a portion of the composite structure (200); 16. The system (100) according to any one of claims 1 to 15, wherein the cover (106) is movable relative to the base (104).

[0169] Appendix 17. The system (100) of Appendix 16, wherein the containment container (102) further includes a retention mechanism (120) configured to hold the cover (106) against the composite structure (200).

[0170] Clause 18. The system (100) of clause 17, wherein the retention mechanism (120) is configured to couple the cover (106) and the base (104).

[0171] Clause 19. The system (100) of clause 17 or 18, wherein the retention mechanism (120) includes at least one clamp (122).

[0172] Clause 20. The system (100) of clause 17, wherein the holding mechanism (120) includes a robotic manipulator (124).

[0173] Appendix 21. The system (100) according to any one of appendices 17 to 20, wherein the base (104) includes a rigid mold (142).

[0174] Clause 22. The system (100) of clause 21, wherein the rigid mold (142) has a molding surface (144) corresponding to the cross-sectional shape (204) of the composite structure (200).

[0175] Clause 23. The system (100) of any one of clauses 1 to 22, further comprising a cowl (146) disposed between the expandable medium (130) and the composite structure (200).

[0176] Clause 24. The system (100) of any one of clauses 1 to 23, further comprising a barrier (162) disposed between the expandable medium (130) and the composite structure (200).

[0177] Note 25. The cover (106) further has a periphery (116); 25. The system (100) of any one of claims 1 to 24, wherein at least a portion of the periphery (116) is configured to contact a composite surface (206) of the composite structure (200).

[0178] Appendix 26. The system (100) described in Appendix 25, wherein at least a portion of the periphery (116) of the cover (106) is configured to be sealed against the composite surface (206) of the composite structure (200).

[0179] Appendix 27. The system (100) of Appendix 25, wherein a portion of the peripheral edge (116) of the cover (106) is configured to contact the base (104) that supports the composite structure (200).

[0180] Appendix 28. The system (100) of any one of appendices 1 to 27, wherein the cover (106) has a cross-sectional profile (118) corresponding to the cross-sectional shape (204) of the composite structure (200).

[0181] Appendix 29. The system (100) of any one of Appendixes 1 to 28, wherein the expansion medium (130) is configured to expand to a predetermined volume (132) upon a predetermined change in an attribute (134) of the expansion medium (130), thereby causing the expansion medium (130) to apply a positive pressure to the composite structure (200) and the cover (106) of the containment container (102).

[0182] Clause 30. The system (100) of clause 29, further comprising a sensor (166) configured to detect the positive pressure.

[0183] Note 31. The expandable medium (130) includes expandable pellets (136); The expandable pellets (136) are heat activated at an activation temperature (152); 31. The system (100) of claim 29 or 30, wherein the expandable pellets (136) are configured to expand upon raising the temperature of the expandable pellets (136) to the activation temperature (152).

[0184] Clause 32. The composite structure (200) includes a plurality of composite layers (208); At least a portion of the composite layer (208) is uncured; 32. The system of claim 31, wherein the activation temperature of the expandable pellets is equal to or less than a curing temperature of the composite layer.

[0185] Clause 33. The system (100) of any one of clauses 31 to 32, wherein the expandable pellets (136) comprise foamable pellets (138).

[0186] Clause 34. The expandable medium (130) further comprises an encapsulation element (154); 32. The system (100) of claim 31, wherein the expandable pellet (136) is disposed within the containment element (154).

[0187] Appendix 35. The system (100) according to any one of appendices 1 to 34, wherein the cover (106) is heat reflective.

[0188] Clause 36. Further comprising a casting (156) disposed between the expandable medium (130) and the composite surface (206) of the composite structure (200); 36. The system (100) of any one of claims 1 to 35, wherein the casting (156) is configured to be hard.

[0189] Clause 37. The system (100) of any one of clauses 1 to 36, further comprising a heater (158) in thermal communication with the expandable medium (130).

[0190] Clause 38. The system (100) of clause 37, wherein the heater (158) is configured to be disposed in the volumetric space (114) of the restraint container (102) together with the expandable medium (130).

[0191] Clause 39. Encapsulating at least a portion (202) of the composite structure (200) in a restraining container (102); Selectively varying the volume (114) of the containment container (102); Inflating an expandable medium (130) disposed in the volume (114); and curing the composite structure (200).

[0192] Note 40. The cover (106) of the containment container (102) includes a plurality of walls (112); 39. The method of claim 39, wherein selectively varying the volume space of the containment container includes moving at least one of the walls relative to at least one other of the walls.

[0193] Clause 41. The method (1000) of clause 40, further comprising supporting at least the portion of the composite structure (200) on a base (104) of the containment container (102).

[0194] Clause 42. The method (1000) of clause 41, further comprising connecting a cover (106) of the containment container (102) to the base (104).

[0195] Clause 43. The method (1000) of clause 42, further comprising moving the cover (106) relative to the base (104).

[0196] Clause 44. Changing an attribute (134) of the expandable medium (130) to expand the expandable medium (130) to a predetermined volume (132); 44. The method (1000) of any one of claims 40 to 43, further comprising applying a positive pressure to the composite structure (200) and the cover (106) of the containment container (102).

[0197] Clause 45. The method (1000) of Clause 44, further comprising raising the temperature of the expandable medium (130) to at least an activation temperature (152).

[0198] Clause 46. The composite structure (200) includes a plurality of composite layers (208); 46. ​​The method (1000) of claim 45, wherein at least a portion of the plurality of composite layers (208) is uncured.

[0199] Appendix 47. The method (1000) of Appendix 46, wherein at least one of the plurality of composite layers (208) is a composite patch (214) configured to repair a portion of a composite surface (206) of the composite structure (200).

[0200] Clause 48. Disposing a casting (156) between the expandable medium (130) and a composite surface (206) of the composite structure (200); 48. The method (1000) of any one of claims 39 to 47, further comprising hardening the casting (156).

[0201] Clause 49. A composite workpiece comprising a composite structure (200) including a plurality of composite plies (208), At least a portion of the plurality of composite layers (208) is uncured; The composite structure (200) is supported by a base (104) of a containment container (102); At least a portion (202) of the composite structure (200) is enclosed in a cover (106) of the containment container (102), the cover having a plurality of walls (112) and a volume (114); At least one of the walls (112) is movable relative to at least one other of the walls (112) to selectively change the volume (114); A composite workpiece (210) in which an expandable medium (130) is disposed in the volume space (114) of the cover (106) between the cover (106) and the composite structure (200) and is configured to expand to a predetermined volume (132) when a predetermined change occurs in a property (134) of the expandable medium (130), whereby the expandable medium (130) applies a positive pressure to the composite structure (200) and the cover (106).

[0202] Appendix 50. The composite workpiece (210) of Appendix 49, wherein at least one of the plurality of composite layers (208) is a composite patch (214) configured to repair a portion of a composite surface (206) of the composite structure (200).

[0203] Clause 51. The expandable medium (130) includes expandable pellets (136); The expandable pellets (136) are heat activated at an activation temperature (152); 51. The composite workpiece (210) of claim 49 or 50, wherein the activation temperature (152) of the expandable pellets (136) is less than or equal to a curing temperature (212) of the plurality of composite layers (208).

Claims

1. a restraint container including a base and a cover, the restraint container having a volume space and configured to enclose at least a portion of the composite structure; an expandable medium configured to be disposed in the volume between at least a portion of the restraint container and the composite structure; The system wherein the volume of the restraining container is selectively variable.

2. the cover of the restraint container includes at least one of a plurality of walls and an overlay; at least one of the walls is configured to be moved relative to at least another of the walls by an actuator to selectively change the volume of the restraint container; The system of claim 1 , wherein the expandable medium is disposed between at least the one of the walls included in the cover and the composite structure.

3. The plurality of walls are: a plurality of side walls; an upper wall; The system of claim 2 , wherein the top wall is movable relative to the plurality of side walls to selectively vary the volume of the restraint container.

4. 4. The system of claim 3, wherein at least one of the plurality of side walls is movable relative to at least one other of the plurality of side walls and relative to the top wall to selectively vary the volume of the restraint container.

5. a plurality of actuators configured to move the top wall and at least one of the plurality of side walls; The system of claim 4 , wherein the expandable medium is disposed between the top wall and the composite structure and between at least the one of the side walls and the composite structure.

6. 4. The system of claim 3, wherein each of the side walls is movable relative to one of the side walls and relative to the top wall to selectively vary the volume of the restraint container.

7. a plurality of actuators configured to move the top wall and each of the plurality of side walls; The system of claim 6 , wherein the expandable medium is disposed between the top wall and the composite structure and between each of the side walls and the composite structure.

8. The cover is a plurality of side walls; The upper wall and a cap; the cap is sealed to the side walls and is movable relative to the side walls and the top wall to selectively change the volume of the restraint container; The system of claim 1 , wherein the expandable medium is disposed between the top wall and the cap.

9. the base supports at least a portion of the composite structure; the cover is movable relative to the base; The system of claim 1 , wherein the restraint container further comprises a retention mechanism configured to hold the cover against the composite structure.

10. the retention mechanism is configured to connect the cover and the base; The system of claim 9 , wherein the holding mechanism includes at least one clamp or robotic manipulator.

11. the base comprises a rigid mold; The system of claim 1 , wherein the rigid mold has a molding surface that corresponds to a cross-sectional shape of the composite structure.

12. The system of claim 1 further comprising a cowl disposed between the inflatable medium and the composite structure.

13. The system of claim 1 , further comprising a barrier disposed between the expandable medium and the composite structure.

14. The cover further has a periphery; at least a portion of the periphery is configured to contact a composite surface of the composite structure; at least the portion of the periphery of the cover is configured to seal against the composite surface of the composite structure; The system of claim 1 , wherein another portion of the periphery of the cover is configured to contact the base that supports the composite structure.

15. The system of claim 1 , wherein the cover has a cross-sectional profile that corresponds to a cross-sectional shape of the composite structure.

16. the inflation medium is configured to expand to a predetermined volume upon a predetermined change in an attribute of the inflation medium, such that the inflation medium applies a positive pressure to the composite structure and the cover of the restraint container; The system of claim 1 , further comprising a sensor configured to detect the positive pressure.

17. the expandable medium comprises expandable pellets; the expandable pellets are heat activated at an activation temperature; the expandable pellets are configured to expand upon raising the temperature of the expandable pellets to the activation temperature; the composite structure includes a plurality of composite plies; at least a portion of the plurality of composite layers are uncured; The system of claim 16 , wherein the activation temperature of the expandable pellets is equal to or less than a curing temperature of the plurality of composite layers.

18. 20. The system of claim 17, wherein the expandable pellets comprise foamable pellets.

19. the expandable medium further comprises an encapsulation element; 20. The system of claim 18, wherein the expandable pellet is disposed within the containment element.

20. The system of claim 1 , wherein the cover is heat reflective.

21. a casting disposed between the expandable medium and the composite surface of the composite structure; The system of claim 1 , wherein the casting is configured to be rigid.

22. further comprising a heater in thermal communication with the expandable medium; The system of claim 1 , wherein the heater is configured to be disposed in the volume of the restraint container along with the expansive medium.

23. A method of using the system according to any one of claims 1 to 22, comprising: Encapsulating at least a portion of the composite structure in the restraint container; selectively varying the volumetric space of the restraint container; expanding an expandable medium disposed in the volume; and curing the composite structure.

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