Systems and methods for locally curing composite structures

Abstract

To provide systems and methods for locally curing composite structures.SOLUTION: A system (100) for locally curing a composite structure (200) includes a constraining container (102) including a cover (106) and having an interior volume (114). The cover (106) is configured to enclose a portion of the composite structure (200). The system (100) also includes a retainer configured to hold the cover (106) against the composite structure (200). The system (100) includes an expandable medium (130) configured to be disposed within the interior volume (114) of the cover (106) between the cover (106) and the composite structure (200).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates generally to composite manufacturing, and more particularly to systems and methods for locally stiffening composite structures. [Background technology]

[0002] Engineered composite materials are used in many applications, typically when composite materials can be manufactured with higher strength, lighter weight, and / or at lower cost than traditional materials. Modern composite materials come in a wide variety of types, with the most common being fiber-reinforced polymer composites, such as glass fiber composites and carbon fiber composites. The manufacturing process for many composite materials typically involves curing composite structures under high temperatures and pressures. Industrial autoclaves are often used to cure composites because they are capable of applying heat and pressure under controlled conditions. However, steps requiring an autoclave can create a bottleneck in the manufacturing process. This is because throughput is dependent on the autoclave's capacity, requiring the transfer of raw materials and uncured parts to the autoclave and the transfer of cured parts from the autoclave. Furthermore, autoclave curing typically cannot accommodate the needs for localized curing, repair, and remote curing. Therefore, those skilled in the art continue to conduct research and development efforts in composite manufacturing. Summary of the Invention

[0003] Disclosed below are examples of systems for locally stiffening composite structures, methods for locally stiffening composite structures, and composite workpieces. The following are non-limiting examples of key features according to the present disclosure, some of which may be claimed and some of which may not be claimed.

[0004] In one example, a system of the present disclosure includes a restraint container having an interior space including a cover, the cover configured to enclose a portion of a composite structure, a retainer configured to hold the cover relative to the composite structure, and an expandable medium configured to be disposed in the interior space of the cover between a wall and the composite structure.

[0005] In one example, the disclosed method includes steps of (1) containing a portion of a composite structure in a restraint container, (2) holding a cover of the restraint container against the composite structure, (3) inflating an expandable medium disposed in an interior space formed by the cover and the composite structure, and (4) curing the composite structure.

[0006] In one example, a composite workpiece of the present disclosure includes a composite structure having a plurality of composite layers, at least some of which are in an uncured or partially cured state, a portion of the composite structure supported by a base, and a cover having an interior space surrounding the portion of the composite structure, wherein an expandable medium is disposed in the interior space between the cover and the composite structure, the expandable medium being configured to expand to a predetermined volume upon a predetermined change in an attribute of the expandable medium, thereby exerting a positive pressure against the composite structure and a wall of the cover.

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

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

[0009] 1-10 , the present disclosure relates to a system 100 and method 1000 for locally curing a composite structure 200, for example. The example system 100 and method 1000 provide an "out-of-autoclave cure" process that can achieve substantially the same quality composite parts as autoclaves, without the need for processing in an autoclave or the large, expensive equipment. The curing process implemented by system 100 and / or performed in accordance with method 1000 provides inexpensive, fast, and small-footprint curing. The curing process implemented by system 100 and / or performed in accordance with method 1000 also allows for repair of cured composite parts (e.g., post-autoclave cured parts) without the need for a secondary cure in an autoclave.

[0010] The present disclosure recognizes that many composite parts require the use of an autoclave to apply heat and pressure to cure (solidify) the composite material. The use of an autoclave requires large amounts of floor space for the equipment and high energy costs. The exemplary system 100 and method 1000 of the present disclosure allows for the use of an expandable material, such as foam, to apply the pressure required for curing and also provides options for controlling heating.

[0011] In various examples, a portion of a pre-cured or partially cured composite component is enclosed or confined within a curing container. The curing container is generally designed to conform to the shape and geometry of the composite component and to contain the intumescent material. In various examples, the intumescent material is disposed between the curing container and the composite component. In various examples, the intumescent material is activated to expand within the curing container. In various examples, heat is used to activate the intumescent material. In some examples, the heat also acts as a catalyst to accelerate the curing of the composite.

[0012] Advantages of system 100 and method 1000 include eliminating and / or reducing the need for large autoclaves, improving factory layout and energy usage. Additionally, the example system 100 and method 1000 cures the composite material using an intumescent material in combination with heat. Additionally, small repair patch jobs can be performed individually without requiring a return to the autoclave for curing. Furthermore, the example system 100 and method 1000 provides the option to cure and / or repair composite parts outside of a factory or other manufacturing environment.

[0013] 1 and 3-10, an example of a system 100 according to the present disclosure is shown. The system 100 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 may be combined in various manners with other examples without the need to include other elements, features, and / or components described in those other examples. Also, such combinations may not be explicitly described or illustrated in the examples provided herein.

[0014] 1 is a schematic block diagram illustrating one or more examples of a system 100. As described in detail herein, in various examples, the system 100 includes multiple components, including one or more of a restraint container 102, a cover 106, a base 104, a wall 112, an overlay 168, a retainer 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 caul 146, a barrier 162, a casting 156, an encapsulation element 154, a bladder 178, a heater 158, an actuator 108, a sensor 166, and a controller 176.

[0015] 3-10 illustrate various examples of the system 100 used to locally cure a portion 202 of a composite structure 200. Generally, the portion 202 of the composite structure 200 refers to the portion of the composite structure 200 that is to be locally cured. For example, the portion 202 may include or refer to at least a portion of the composite structure 200 that is uncured, partially cured, or in need of repair.

[0016] In various examples, the system 100 is an adjustable forming tool system including a restraint container 102 and an expandable medium 130 (FIGS. 5-8). The restraint container 102 is selectively positionable relative to a composite structure 200, such that at least a portion 202 of the composite structure 200 and the expandable medium 130 are disposed within or restrained by the curing container. The system 100 is configured to facilitate application of a positive pressure to the portion 202 of the composite structure 200 by expansion of the expandable medium 130 during a process to locally cure the portion 202 of the composite structure 200. In various examples, the composite structure 200 is uncured, partially cured, or in need of repair. The restraint container 102 and the expandable medium 130 are configured to apply a positive pressure to the composite structure 200 during a process to cure the composite structure 200.

[0017] Referring to FIG. 1 , in various examples, a composite structure 200 is a composite part, component, object, etc. that includes one or more composite layers 208 (also referred to as plies) that are bonded together through curing (e.g., by applying heat and / or pressure). The composite structure 200 may include any suitable number of composite layers 208. In various examples, the 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 examples, at least some of the composite layers 208 are uncured or partially cured, or are repair patches or fillers (e.g., composite patches 214). In one or more examples, the activation temperature 152 of the expandable medium 130 (e.g., expandable pellets 136) is lower than the curing temperature 212 of the composite layers 208. For example, the activation temperature 152 is lower than the curing temperature of at least a portion of the composite layer 208 in an uncured or partially cured state, or the curing temperature of at least a portion of the composite layer 208 formed by a repair patch (e.g., composite patch 214). In one or more examples, the activation temperature 152 of the intumescent medium 130 (e.g., intumescent pellets 136) is at least the same as the curing temperature 212 of the composite layer 208. For example, the activation temperature 152 is the same as the curing temperature of at least a portion of the composite layer 208 in an uncured or partially cured state, or the curing temperature of at least a portion of the composite layer 208 formed by a repair patch (e.g., composite patch 214). In one or more examples, the activation temperature 152 of the intumescent medium 130 (e.g., intumescent pellets 136) is higher than the curing temperature 212 of the composite layer 208. For example, activation temperature 152 is a temperature higher than the curing temperature of at least a portion of composite layer 208 in an uncured or partially cured state, or at least a portion of composite layer 208 formed by a repair patch (e.g., composite patch 214).

[0018] 1 and 3-10 , in one or more examples, the cover 106 forms a portion of the restraint container 102. Examples of such examples include cases where at least the portion 202 of the composite structure 200 is supported by the base 104. In one or more examples, the cover 106 forms the entire restraint container 102. Examples of such examples include cases where at least the portion 202 of the composite structure 200 is supported by other reinforcing members or is unsupported. 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 disposed within or restrained by the cover 106. In these examples, the cover 106 includes (e.g., forms or defines) the interior space 114 and is configured to enclose the portion 202 of the composite structure 200.

[0019] In one or more examples, the cover 106 does not substantially expand when pressure is applied to at least the interior surface of the cover 106. As such, pressure applied to the exterior surface of the composite structure 200 (e.g., the composite surface 206) cooperates with the cover 106 to create a compressive force on the composite structure 200.

[0020] 3, in one or more examples, the cover 106 is movable relative to the composite structure 200, thereby allowing for selection, individualization, and / or targeting of the portions 202 of the composite structure 200 to be cured. The movement of the cover 106 facilitates localized curing of individual areas or portions of the composite structure 200. In one or more examples, the cover 106 can be completely removed from the composite structure 200, such as after curing has occurred.

[0021] In one or more examples, the cover 106 has a size and / or dimension suitable to cover at least the portion 202 to be cured. In these examples, a dimension (e.g., length and / or width) of the cover 106 is less than at least one dimension (e.g., length and / or width) of the composite structure 200. As shown in FIG. 3 , in one or more examples, the cover 106 is movable and selectively positioned along the length of the composite structure 200.

[0022] 1 and 4-10, the cover 106 has a cross-sectional profile 118. In one or more examples, the cross-sectional profile 118 of the cover 106 may correspond 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 to the cross-sectional shape 204 of the portion 202 of the composite structure 200 that is to be cured, the interior space 114 that needs to be filled with the expandable medium 130 during inflation may be reduced.

[0023] 1, 3-6, and 9, in one or more examples, the cover 106 includes a wall 112. In one or more examples, the wall 112 forms or defines at least a portion of the interior space 114. In one or more examples, the wall 112 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.

[0024] In these examples, the expandable medium 130 is configured to be disposed within the interior space 114 of the cover 106 formed by the wall 112. In one or more examples, the expandable medium 130 is disposed between the wall 112 and the portion 202 of the composite structure 200.

[0025] In one or more examples, at least a portion of the cover 106, such as the wall 112 of the cover 106, is rigid (e.g., hard or inflexible) and does not expand. In these examples, at least a portion of the cover 106, such as the wall 112, can be made of any suitable material, such as, for example, but not limited to, a metallic material, a composite material, a cementitious material, a ceramic material, a polymeric material, etc. In these examples, the wall 112 restrains the expansion medium 130 and resists the positive pressure generated by the expansion medium 130 upon expansion. In these examples, the wall 112 can withstand the pressure generated within the containment container 102 upon expansion of the expansion medium 130.

[0026] 1 , 7 , and 8 , in one or more examples, the cover 106 includes an overlay portion 168. In one or more examples, the overlay portion 168 forms or defines at least a portion of the interior space 114. In one or more examples, the overlay portion 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.

[0027] In these examples, the expandable medium 130 is configured to be disposed within the interior space 114 of the cover 106 formed by the overlay portion 168. In one or more examples, the expandable medium 130 is disposed between the overlay portion 168 and the portion 202 of the composite structure 200.

[0028] In one or more examples, at least a portion of the cover 106, such as the overlay portion 168 of the cover 106, is flexible and does not expand. As shown in FIG. 7 , the use of the overlay portion 168 allows the cover 106 to conform to (e.g., more closely match) the profile of the composite structure 200. Additionally or alternatively, the cover 106 can conform to (e.g., more closely match) the profile of the expandable medium 130 disposed between the cover 106 and the composite structure 200 prior to expansion. In these examples, at least a portion of the cover 106, such as the overlay portion 168, can be made of any suitable material, such as, but not limited to, a metal mesh (e.g., chain mail), a ceramic mesh, a polymer mesh, or the like. In these examples, the overlay portion 168 restrains the expandable medium 130 and resists the positive pressure generated by the expandable medium 130 upon expansion. In these examples, the overlay portion 168 is capable of withstanding the pressure generated within the restraint container 102 upon inflation of the expandable medium 130 .

[0029] In one or more examples, at least a first portion of the cover 106 is flexible and non-distensible, and at least a second portion of the cover 106 is rigid and non-distensible. As one example, the cover 106 can include an overlay portion 168 and at least one wall portion 112. In other examples, at least a first portion of the cover 106 is non-distensible (e.g., flexible and / or rigid), and at least a second portion of the cover 106 is distensible.

[0030] 1 and 3 , in one or more examples, the cover 106 includes a perimeter 116. At least a portion of the perimeter 116 is configured to contact a 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 contain the expandable medium 130 disposed in the interior space 114. In these examples, the portion 202 of the composite structure 200 is disposed within or surrounded by the perimeter 116 of the cover 106.

[0031] In one or more examples, at least a portion of the periphery 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 vacuum pressure (e.g., negative pressure) to be used during the curing process and as a means to hold the cover 106 in place on the composite surface 206.

[0032] 1 , in one or more examples, the interior space 114 of the cover 106 can be selectively (e.g., controllably) varied. In one or more examples, at least one of the walls 112 of the cover 106 is movable to alter (e.g., reduce) the interior space 114 of the cover 106. Selectively altering or varying the interior space 114 can reduce the interior space 114, which can concomitantly reduce the amount of expandable media 130 required to fill the interior space 114 upon inflation.

[0033] 1 , in one or more examples, at least one actuator 108 is used to selectively move at least one of the walls 112 of the cover 106 to change the interior space 114 of the cover 106. In these examples, the actuator 108 is connected to the wall 112. Actuation of the actuator 108 causes movement of the wall 112. The actuator 108 may include any suitable type of controlled drive device, such as a mechanical actuator, a pneumatic actuator, a linear actuator, a rotary actuator, etc.

[0034] In one or more examples, the sensor 166 is configured to detect or measure the positive pressure or force exerted by the inflation medium 130 during inflation of the inflation medium 130. In these examples, the controller 176 (FIG. 1) receives input signals or data from the sensor 166 and controls the actuator 108 to increase or decrease the interior space 114 as needed to maintain the desired pressure exerted on the composite structure 200. The sensor 166 may include any suitable type or number of pressure sensors, load sensors, or other sensor devices.

[0035] In one or more examples, the controller 176 includes, takes the form of, or utilizes a closed-loop controller to provide control over the pressure within the restraint container 102 and / or the pressure applied to the composite structure 200. In one or more examples, the interior space 114 can be varied in response to real-time pressure measured by the sensor 166. Closed-loop control can effectively improve the quality of composite manufacturing and repair because the closed-loop control mechanism can compensate for multiple variables, such as material batch variations, humidity, and environmental temperature. In one or more examples, the controller 176 uses the pressure measurements from the sensor 166 to control the pressure within the restraint container 102 and / or the pressure applied to the composite structure 200 by increasing or decreasing the interior space 114. This increase or decrease in the interior space can be achieved, for example, 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 interior space 114.

[0036] In one or more examples, 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 as a way to control the pressure within the restraint container 102 and / or the pressure applied to the composite structure 200. In various examples, the expansion and / or contraction of the expansion medium 130 can be controlled by any of a variety of methods, such as applying heat or cooling to the expansion medium 130.

[0037] In other examples, the system 100 includes other mechanisms for preventing over-pressurization and / or regulating the pressure in the interior space 114 of the containment container 102. As an example, the cover 106 may be fixed in place relative to the composite structure 200, for example, attached to the base 104 by a plurality of shear pins. In these examples, the shear pins are configured to break under a predetermined pressure, thereby releasing the cover 106 and allowing the pressure to escape.

[0038] In various examples, the cover 106 includes any suitable element or feature that facilitates the introduction and / or removal of the expansion medium 130 from the interior space 114. In one or more examples, the cover 106 includes a removable or openable panel (e.g., a door) that, after being positioned relative to the composite structure 200, allows access to the interior space 114 and the introduction of the expansion medium 130.

[0039] In one or more examples, at least a portion of the cover 106 is heat reflective. For example, at least one of the walls 112 of the cover 106 is heat reflective. For another example, the overlay 168 is heat reflective. In one or more examples, 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 and activate expansion of the expandable medium 130 during the curing process.

[0040] 1, 3, and 9, in one or more examples, retainer 120 is configured to hold cover 106 against composite structure 200. Retainer 120 includes any suitable mechanism capable of securing cover 106 against portion 202 of composite structure 200 during curing.

[0041] In one or more examples, the retainer 120 includes at least one clamp 122. In these examples, the clamp 122 fastens or secures the cover 106 in place relative to the composite structure 200. In one or more examples, the clamp 122 fastens or secures the cover 106 to the composite structure 200. In one or more examples, the clamp 122 fastens or secures the cover 106 to another component (e.g., the base 104 or a supporting structure). The clamp 122 may include any suitable type of clamping or fastening device, such as, but not limited to, a mechanical clamp, a magnetic clamp, a pneumatic clamp, a spring clamp, a latch, a pin, a fastener, a weight, etc. The retainer 120 may include any number of clamps 122.

[0042] 1 , in one or more examples, the retainer 120 includes a robotic manipulator 124. In these examples, the robotic manipulator 124 holds or secures the cover 106 in a predetermined position relative to the composite structure 200. In these examples, the cover 106 is connected to a working end (e.g., an end effector) of the robotic manipulator 124. Under computer control, the robotic manipulator 124 selectively positions the cover 106 relative to the composite structure 200 and holds the cover 106 in the appropriate position for curing the portion 202 of the composite structure 200.

[0043] 1 and 3-9, in one or more examples, the base 104 is configured to support the composite structure 200. In one or more examples, the base 104 forms a portion of the containment container 102. In one example, the composite structure 200 is disposed on or supported by the base 104. In another example, the base 104 provides or serves as structural reinforcement for at least the portion 202 of the composite structure 200 that is enclosed by the cover 106 and intended to be locally cured in the system 100.

[0044] 4-8, the composite structure 200 is positioned on the base 104 during the curing process. At least the portion 202 of the composite structure 200 being locally cured must be stably supported in order to apply an appropriate compressive force (e.g., positive pressure) to the composite structure 200 while it is positioned within the restraint container 102. In one or more examples, the base 104 provides a substantially incompressible surface for supporting the underside of the composite structure 200.

[0045] In one or more examples, the base 104 is configured to substantially resist compression when pressure is applied to at least the upper surface of the base 104 (e.g., molding surface 144), i.e., the surface that contacts the lower surface of the composite structure 200. In this manner, pressure applied to the outer surface of the composite structure 200 (e.g., composite surface 206), in cooperation with the base 104, generates a compressive force on the composite structure 200.

[0046] As shown in FIGS. 3-9 , in one or more examples, the shape of the base 104 is appropriately configured to define or correspond to a desired cross-sectional shape 204 of the composite structure 200. In one or more examples, the base 104 includes a rigid mold 142. In one or more examples, the rigid mold 142 includes a molding surface 144. In one or more examples, 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 examples, the rigid mold 142 has an upper molding surface 144 suitable for forming and / or supporting a three-dimensional shape of the composite structure 200. As shown in FIG. 9 , in one or more examples, the rigid mold 142 has a planar or flat molding surface 144 suitable for forming and / or supporting a two-dimensional shape of the composite structure 200.

[0047] In one or more examples, the base 104 is a forming tool used in the layup and forming process of the composite structure 200. In one or more examples, the base 104 is a curing tool used in a curing process, such as an initial cure in an autoclave. In one or more examples, the base 104 is a repair tool used in a localized curing process, such as a secondary cure or repair process outside of an autoclave.

[0048] 1, 3, and 9, in one or more examples, the retainer 120 is configured to attach to the base 104. In one or more examples, the retainer 120 is configured to couple the cover 106 and the base 104. In these examples, the combination of the cover 106 and the base 104 forms the restraint container 102 in which the portion 202 of the composite structure 200 and the expandable medium 130 are contained during the localized curing process (see, e.g., FIGS. 6-8).

[0049] In one or more examples, the retainer 120 is configured to be attached to the rigid mold 142. In one or more examples, the retainer 120 is configured to couple the cover 106 and the rigid mold 142 together.

[0050] In one or more examples, a portion of the periphery 116 of the cover 106 is configured to contact the base 104 that supports the composite structure 200 .

[0051] 1, 4, 5, and 10, in one or more examples, an intermediate layer 164 is disposed or provided between the inflatable medium 130 and at least the portion 202 of the composite structure 200. In one or more examples, the intermediate layer 164 includes or takes the form of a barrier 162 (e.g., a barrier film), a cowl 146 (e.g., a cowl plate or cowl sheet), or other suitable layer of material (e.g., a casting member 156, a bladder 178, etc.). In these examples, the intermediate layer 164 is disposed prior to adding the inflatable medium 130 to the interior space 114 of the restraint container 102.

[0052] In one or more examples, the barrier 162 provides reduced porosity and / or good adhesion. The barrier 162 is selected to be heat resistant and easily removable after the composite structure 200 is cured. Materials for the barrier 162 include, for example, silicone-based films, polymer-based films, and / or fluorine-containing polymer-based films. In one or more examples, the barrier 162 is incorporated into a vacuum bag that contains the composite structure 200.

[0053] In one or more examples, cowl 146 can improve the adhesion and surface condition of composite structure 200. Cowl 146 is selected to be heat resistant and easily removable after composite structure 200 has cured. Materials for cowl 146 can include, for example, rigid materials, semi-rigid materials, metallic materials, composite materials, etc.

[0054] In one or more examples, as shown in Figure 10, the cowl 146 includes or is formed of multiple cowl sections. In these examples, each cowl section is separate from the other cowl sections and is movable (e.g., shiftable or slidable) relative to adjacent cowl sections. In one or more examples, the ends of adjacent cowl sections overlap. The individual cowl sections of the cowl 146 can provide good adhesion and surface integrity.

[0055] In one or more examples, the intermediate layer 164 includes or takes the form of a casting element 156. In one or more examples, the casting element 156 is disposed between the expandable medium 130 and the composite surface 206 of the composite structure 200. In these examples, the casting element 156 is configured to cure, such as in response to a change in temperature or time, or a change in the properties of the material comprising the casting element 156. As an example, the casting element 156 is attached to or formed in the portion 202 of the composite structure 200 prior to adding the expandable medium 130. In one or more examples, the casting element 156 is configured to cure before or during the curing process. The casting element 156 is selected to be heat resistant and easily removable after the composite structure 200 has cured. In one or more examples, the casting element 156 can improve adhesion. The casting element 156 is selected to be heat resistant and easily removable after the composite structure 200 has cured. Examples of materials for the casting member 156 include epoxy, rubber, plaster, cement, and the like.

[0056] In one or more examples, the casting member 156 contains a casting material. In one or more examples, the casting material is configured to harden when a predetermined change in an attribute of the material occurs. For example, the casting material may harden in response to a change in temperature, time, chemical composition, pressure, or a change in an attribute of the material comprising the casting member 156. In one or more examples, the casting material is heat-activated. In these examples, the predetermined change in the attribute of the casting material includes a change in temperature of the casting material as a whole and / or a change in temperature of one or more portions of the casting material. Thus, causing a predetermined change in the attribute of the casting material may include increasing the temperature of the casting member 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 suitable for the expansile element to undergo a predetermined expansion, such as a few degrees above ambient temperature). The casting material then solidifies or hardens due to the increase in temperature. In these examples, the heat-activated casting material is configured to harden when the temperature of the casting material is raised to at least a predetermined temperature. In one or more examples, 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 between or a product of values ​​associated with each of the properties of the casting material. In one or more examples, the casting material includes two materials (e.g., a two-component 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 combined. In one or more examples, the casting material includes a resin-based composite that solidifies or hardens in response to exposure to a specific wavelength of light (e.g., blue light in the 400-500 nm range). In one or more examples, the curing or accelerated curing of the casting member 156 is achieved using a combination of curing techniques, such as heat and two-component mixing, heat and ultraviolet (UV) curing, or a combination of other curing techniques.If heat is required to cure or accelerate the cure of the casting 156, the heating temperature is generally at or below the composite cure temperature.

[0057] In one or more examples, the casting material is heat-reflective or includes a heat-reflective material, liner, or layer. As one example, the casting member 156 can include at least one heat-reflective film as one of the layers comprising the casting member. The heat-reflective film can be the innermost layer, a middle or inner layer, and / or the outermost layer of the casting member. The heat-reflective properties of the casting member 156 can facilitate heating of the expandable medium 130 and activate the expansion of the expandable medium 130 during the curing process.

[0058] In one or more examples, the intermediate layer 164 includes or takes the form of a bladder 178. In one or more examples, the bladder 178 is filled with a fluid (e.g., gas or liquid) to improve the adhesion and surface condition of the composite structure 200. In one or more examples, the bladder 178 is configured to equalize the positive pressure applied to the composite structure 200, thereby allowing for uniform application of positive pressure across the composite surface 206. The bladder 178 is selected to be heat resistant and easily removable after the composite structure 200 has cured.

[0059] In other examples, system 100 may include multiple of the various intermediate layers 164 described above. For example, system 100 may include multiple or any combination of encapsulation element 154, cowl 146, casting member 156, and barrier 162.

[0060] 1 , in one or more examples, 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, thereby allowing the inflation medium 130 to apply or exert a positive pressure against the composite structure 200 and the wall 112 of the cover 106. In one or more examples, the predetermined volume 132 of the inflation medium 130 in its expanded state is greater than the volume of the interior space 114 of the restraint container 102. Generally, the "predetermined volume" refers to the actual available and fillable interior volume of the interior cavity of the restraint container 102 (e.g., the volume of the interior space 114). In various examples, the predetermined volume 132 is substantially the same as or slightly larger than the volume of the interior space 114, and once the inflation medium 130 is expanded to the predetermined volume 132, the inflation medium 130 applies a positive pressure to the composite structure 200 unless the interior space 114 is altered (e.g., using a movable wall 112, a controllable inflation element 196, etc.). Typically, the amount (e.g., volume) of unexpanded inflation medium 130 introduced into the interior space 114 of the restraint container 102 is established by using tests or models to predict the inflation and post-expansion pressures in the confined space.

[0061] 1 and 5-8, in one or more examples, the expandable medium 130 includes expandable pellets 136. In one or more examples, the expandable pellets 136 are thermally activated at an activation temperature 152. In these examples, the expandable pellets 136 are configured to expand when the temperature of the expandable pellets 136 is raised to the activation temperature 152.

[0062] In one or more examples, any suitable number of expandable pellets 136 can be disposed within the interior space 114 of the containment container 102, provided that the expandable pellets, in their expanded state, are capable of applying sufficient positive pressure against the composite surface 206 of the composite structure 200 upon curing to consolidate and mold the composite structure 200. The number of expandable pellets 136 depends on the size of the interior space 114. For example, if the containment container 102 conforms to the contours of the composite structure 200, a relatively small number of expandable pellets 136 may be required. In various examples, each expandable pellet 136 can have any suitable dimensions. In one or more examples, the length of the expandable pellet 136 is less than about one centimeter. The expandable pellets 136 can be substantially uniform in size, or can include pellets of different sizes.

[0063] In one or more examples, the activation temperature 152 of the expandable pellets 136 may be less than, at least equal to, or greater than the cure temperature 212 of the composite structure 200. In one or more examples, the activation temperature 152 of the expandable pellets 136 may be less than, at least equal to, or greater than the cure temperature 212 of at least some of the composite plies 208 that form the composite structure 200.

[0064] 1 , in one or more examples, the expandable pellets 136 include foamable pellets 138. In one or more examples, the foamable pellets 138 are configured to expand when heated to at least a predetermined foaming temperature. In one or more examples, the expandable pellets 138 may include a foamable material, such as a thermoplastic material treated with a foaming agent. Alternatively, the foaming agent may be replaced with other suitable components configured to expand when heated, such as gas-filled balloons, hollow microspheres, metals, or any combination thereof.

[0065] 1 , in one or more examples, the expandable medium 130 includes an encapsulation element 154. In these examples, the expandable pellets 136 are disposed within the encapsulation element 154. In these examples, the encapsulation element 154 may surround the expandable medium 130 (e.g., the expandable pellets 136) to facilitate handling of the expandable medium 130 and to facilitate removal of the expandable medium 130 after curing is complete. In one or more examples, the encapsulation element 154 is non-expandable. In one or more examples, the encapsulation element 154 is expandable.

[0066] 1 and 10 , in one or more examples, the expandable medium 130 is disposed within an encapsulation element 154. In these examples, the encapsulation element 154 may surround the expandable medium 130 (e.g., expandable pellets 136) to facilitate handling of the expandable medium 130 and facilitate removal of the expandable medium 130 after curing is complete. In one or more examples, the encapsulation element 154 is non-expandable. In one or more examples, the encapsulation element 154 is expandable. The encapsulation element 154 may take any suitable form, such as an encapsulating film, a sealant layer, a bag, a pouch, or the like.

[0067] In one or more examples, the heater 158 is capable of transferring heat to the expandable medium 130. The heater 158 is configured to heat the expandable medium 130 to an activation temperature 152, whereupon the expandable medium 130 expands within the interior space 114 and applies a positive pressure to the composite structure 200. In one or more examples, the heater 158 is an internal heater and is disposed within the interior space 114 of the restraint container 102 along with the expandable medium 130. In one or more examples, the heater 158 is an external heater and is disposed outside the restraint container 102. The heater 158 may take any suitable form and may include any suitable heating device. In various examples in which the expandable medium 130 is heat-activated for expansion, the restraint container 102, or at least the cover 106, may be heated externally. Alternatively, or in addition, 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.

[0068] In various embodiments, the restraint container 102 includes multiple components, such as a base 104 and a cover 106. In one or more examples, 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 examples, the composite structure 200 is supported by another type of structure, such as a lower component of the composite structure 200. The cover 106 is selectively positioned relative to the composite structure 200 to enclose the portion 202 to be cured. The cover 106 is attached to or positioned over the composite structure 200 such that the portion 202 of the composite structure 200 is positioned within the interior space 114 of the restraint container 102. The expansion medium 130 is placed (e.g., added or poured) into the interior space 114 of the restraint container 102 such that the expansion medium 130 is at least adjacent to a portion 202 of the composite structure 200 (e.g., an uncured portion, a partially cured portion, a repaired portion) and is positioned opposite the base 104 or other supporting reinforcement member.

[0069] Prior to the curing process, the expansion medium 130 is in an unexpanded state (e.g., FIGS. 5 and 7). In the unexpanded state, the expansion medium 130 may be referred to as an unexpanded or unexpanded element. During the curing process, the expansion medium 130 expands to an expanded state (e.g., FIGS. 6 and 8). In the expanded state, the expansion medium 130 may be referred to as an expansion or an expansion element. In the expanded state, the expansion medium 130 applies pressure against the interior surface of the containment container 102 (e.g., cover 106) and the surface of the portion 202 of the composite structure 200 (e.g., uncured composite workpiece). The expanded expansion medium 130 applies positive pressure (due to the expansion of the expansion medium 130) against the composite structure 200 to promote adhesion during part or all of the curing process. 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.

[0070] In this disclosure, the terms "expandable," "expansion," "expanding," and similar terms refer to the ability to expand or to have the potential or capacity to increase in size and / or volume. An expandable material or separate element can increase in size or volume symmetrically or asymmetrically. When an expandable material is symmetrically expandable, the material can expand to a substantially equal extent along each axis. When an expandable material exhibits asymmetric expansion, the material can expand to a greater extent along a first axis, or along both a first axis and a second axis, compared to along other axes.

[0071] In various examples, composite manufacturing can be performed without the use of an industrial autoclave by applying pressure to an uncured composite workpiece using a restraint container 102. By using a restraint container 102 that is substantially 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 expandable medium 130 can be minimized, and individual portions of the composite structure 200 can be cured locally outside of an autoclave.

[0072] In various examples, 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 of the expansion medium 130, or a combination thereof, and / or other suitable property 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 may 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 high temperature. Thus, when curing the composite structure 200 includes increasing the temperature of the composite structure 200, the expansion medium 130 expands in the interior space 114 during the curing process. The expansion medium 130 (eg, during or after expansion) applies pressure to the inside of the restraint container 102 and to the uncured portions of the composite structure 200 during the curing process.

[0073] In various examples, the expansion medium 130 is selected so that, when expanded within the interior space 114 of the containment container 102, it exerts sufficient pressure to effectively consolidate the composite material during its curing process. For some composite materials, pressures of less than 1 atmosphere may be sufficient to consolidate and cure, while other composite materials may be more effectively cured at pressures of 1 atmosphere or greater. The expansion medium 130 may be selected to generate sufficient pressure to allow for the application of pressures that would previously require an autoclave (e.g., 1-5 atmospheres).

[0074] In various examples, the curing process can be simplified and facilitated by adding the expandable medium 130 as a plurality of expandable pellets 136 (also referred to as expandable beads). In these examples, the expandable pellets 136 are configured to expand in volume when heated to at least a predetermined temperature. In one or more examples, the expandable medium 130 includes one or more different types of expandable pellets 136, each configured to expand (e.g., to a predetermined volume) when heated to a predetermined temperature. As an example, the expandable pellets 136 can be formulated to achieve a desired relationship between the volume of each expandable pellet 136 and the temperature of that expandable pellet 136 as a function of time.

[0075] In various examples, 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, a desired degree of expansion and force can be achieved by varying the formulation. This allows the number and composition of expandable pellets 136 employed to be selected so that the 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.

[0076] In one or more examples, the system 100 includes additional elements configured to modify or mitigate the pressure exerted by the expansion medium 130, including, but not limited to, one or more volume-invariant elements 172 (e.g., substantially incompressible elements) and / or one or more contractile elements 174 (e.g., fluid-filled bladders) that reduce in volume after curing to facilitate access to the composite structure 200.

[0077] In one or more examples, the system 100 may also include one or more inflatable elements 196 ( FIG. 1 ). In these examples, the inflatable element 196 is disposed within the interior space 114 of the containment container 102. In one or more examples, the inflatable element 196 is configured to selectively expand and contract, thereby selectively increasing or decreasing the volume of the interior space 114 of the containment container 102 that can be filled with the expansion medium 130 as the expansion medium 130 expands. In one or more examples, the inflatable element 196 includes or takes the form of a sealed bladder or balloon containing some type of expansion medium (e.g., the expansion medium 130). As one example, a chemical (e.g., baking soda powder) can be disposed within the balloon. Heating the chemical to generate a gas can expand the balloon, thereby decreasing the fillable volume of the interior space 114 of the containment container 102 or applying a positive pressure to the containment space. In other examples, the inflatable element 196 is an example of the expansion medium 130.

[0078] 4-8 illustrate an example 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 enclose the portion 202 of the composite structure 200. In one example, the portion 202 of the composite structure 200 is covered or encased by a cover 106. The cover 106 is configured to facilitate applying pressure to a composite surface 206 of the composite structure 200 by expansion of an expandable medium 130. In one or more examples, the composite structure 200 is disposed on a base 104 or, if necessary, is supported by the cover 106 and a reinforcing member on a side opposite the direction of positive pressure. As shown in FIGS. 4-6, in one or more examples, the wall 112 of the cover 106 defines an interior space 114 of the restraint container 102. As shown in FIGS. 7 and 8, in one or more examples, the overlay portion 168 of the cover 106 defines the interior space 114 of the restraint container 102.

[0079] 5 and 7, the inflation medium 130 is introduced into the interior space 114. An appropriate amount of inflation medium 130 is used such that during and / or after inflation, the inflation medium 130 contacts both the composite structure 200 and the interior surface of the cover 106, creating and applying a positive pressure against the composite surface 206 of the composite structure 200.

[0080] The expansion medium 130 may take any suitable form. In one or more examples, the expansion medium 130 is dispensed into the containment container 102 in the form of pellets, beads, particles, powder, or foam, for example. Alternatively, or in addition, the expansion medium 130 may be dispensed into the containment container 102 as a solid or semi-solid, independent member. Examples of such a layer include a layer of expansion medium 130 that can cover the portion 202 of the composite structure 200 over a predetermined area. The layer of expansion medium 130 can be provided as individual encapsulation elements 154 (e.g., pouches or bags) filled with small granular portions of the expansion medium 130, such as pellets or beads. While the expansion medium 130 is shown in FIGS. 6 and 7 as a plurality of expansion pellets 136, this is merely a representative example and is not intended to limit the structure or configuration of the expansion medium 130.

[0081] In various examples, the expansion medium 130 is added in an unexpanded state to the interior space 114 of the restraint container 102. As shown in Figures 6 and 8, before and / or during the curing process, the expansion medium 130 is configured to expand (e.g., increase in volume) to at least partially fill the interior space 114, thereby causing the expansion medium 130 (in its expanded state) to directly or indirectly apply positive pressure against at least a portion of the interior surface of the cover 106 and the composite surfaces 206 (e.g., the top and / or outer surfaces) of the composite structure 200. The pressure applied by the expansion medium 130 as it expands helps to compress and consolidate the portions 202 of the composite structure 200 during curing.

[0082] In various examples, the expansion medium 130 is configured to expand (e.g., 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 uninflated state). In one or more examples, the expansion medium 130 is placed (e.g., introduced or added) into the interior space 114 of the restraint container 102 in an uninflated state. The predetermined change occurs in the property 134 of the expansion medium 130 when the expansion medium 130 is in the interior space 114 in an uninflated state. The expansion medium 130 expands in response to the predetermined change. The property 134 of the expansion medium 130 may be a physical and / or chemical property.

[0083] In one or more examples, 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 increases in volume upon absorbing water. For example, anhydrous calcium sulfate (anhydrite) exhibits a volume increase of approximately 61% upon absorbing water to form gypsum. In these examples, water can be added directly to the expansion medium 130, which can be accomplished, for example, by adding liquid water or water vapor to the interior of the containment container 102. Alternatively, or in addition, water or water vapor can be generated within the containment container 102 itself, for example, by a suitable chemical reaction.

[0084] In one or more examples, the predetermined change in the attribute 134 of the expansible medium 130 includes a temperature change of the expansible medium 130 and / or a temperature change of one or more portions of the expansible medium 130. Thus, causing the predetermined change in the attribute of the expansible medium 130 may include raising the temperature of the expansible element in its unexpanded state from a low temperature, such as an ambient temperature (e.g., room temperature), to at least an initial temperature or a predetermined temperature above the ambient temperature (e.g., a temperature suitable for causing the predetermined expansion of the expansible element, such as a temperature a few degrees above the ambient temperature). The expansible element then undergoes thermal expansion due to the increase in temperature.

[0085] In one or more examples, the expansion medium 130 is a heat-activated expansion element. In these examples, the heat-activated expansion element is configured to expand when the temperature of the expansion medium 130 is raised to at least a predetermined temperature. Alternatively, or in addition, the expansion medium 130 can be heated to at least a predetermined temperature to expand the expansion medium 130, thereby creating a predetermined pressure on the composite structure 200. Typically, the predetermined pressure is sufficient to adequately cure the composite material.

[0086] In one or more examples, the predetermined change in the attribute 134 of the expansion medium 130 occurs in a combination of two or more properties of the expansion medium 130, and is expressed as a ratio or product of numerical values ​​related to the properties of the expansion medium 130, such as two materials with different thermal expansion coefficients.

[0087] In various examples, the process of curing the composite structure 200 includes causing a predetermined change in an attribute 134 of the expandable medium 130. In one or more examples, the expansion of the expandable medium 130 occurs automatically during the curing process. For example, the attribute 134 is the temperature of the expandable medium 130, and heat applied to the work assembly 250 during the curing process can cause a predetermined change in the temperature of the expandable medium 130. That is, heat applied to the work assembly 250 during the curing process can raise the temperature of the expandable medium 130 to at least a desired volume and / or a predetermined temperature associated with a desired volume increase. One or more properties of the expandable medium 130 can be designed so that temperature changes experienced by the expandable medium 130 during curing of the composite structure 200 cause the expandable medium 130 to thermally expand by a predetermined desired amount. Alternatively, or in addition, expanding 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 may include applying an electric field, injecting a liquid, gas, and / or other suitable material, and / or causing other suitable changes to the expansion medium 130.

[0088] In various examples, the expandable medium 130 is a heat-expandable medium, including any material capable of expanding when a predetermined temperature is reached. In certain examples, the group of plastic polymers that can be softened by heating 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 remoldable, specifically, expandable.

[0089] Various types of thermoplastic materials are known, including 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 expansion medium 130 comprising acrylonitrile butadiene styrene (ABS) polymers may exhibit favorable physical properties when used in combination with the examples described herein.

[0090] In one or more examples, the expandable medium 130 (e.g., expandable pellets 136) can further include a foaming agent. The foaming agent is selected to form multiple pores, cavities, 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 that permeates the expandable medium 130 under pressure. Such a foaming agent can be configured to expand at multiple 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 higher temperature, with the expanded gas forming the pores, cavities, or voids. If a foaming agent is used, it can be applied to the expandable medium 130 before heating.

[0091] In examples where the expansion medium 130 includes a blowing agent, the blowing agent may be any suitable substance capable of achieving the desired degree of expansion. The blowing agent may include a physical blowing agent, such as a chlorofluorocarbon, a hydrochlorofluorocarbon, a hydrocarbon, or liquid carbon dioxide. Alternatively, or in addition, the blowing agent may include a chemical blowing agent selected to react with one or more components of the expansion medium 130. Examples of such chemical blowing agents include isocyanates and water for polyurethanes, azodicarbonamide for vinyls, hydrazine or other nitrogen-based materials for thermoplastic and elastomeric foams, and sodium bicarbonate for thermoplastic foams.

[0092] In examples where the expandable medium 130 includes a foaming agent, the foaming agent may include a foaming agent. In these examples, 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 sodium laureth sulfate, sodium lauryl ether sulfate (SLES), sodium lauryl sulfate (also known as sodium dodecyl sulfate or SDS), and ammonium lauryl sulfate (ALS).

[0093] During the curing process of the composite structure 200, the expandable medium 130 (e.g., expandable pellets 136) is expanded from an unexpanded state ( FIGS. 5 and 7 ) to an expanded state ( FIGS. 6 and 8 ). In one or more examples, the expandable pellets 136 are configured to expand in response to heat applied to the work assembly 250 during curing. The expandable pellets 136 expand to fill the interior space 114 of the cover 106, and the expanded expandable pellets 136 apply a positive pressure to the composite structure 200, causing the composite structure 200 to cure.

[0094] In one or more examples, 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. The degree of deformability allows the expandable medium 130 to fill small gaps that may naturally occur, for example, between pellets, between pellets and the inner surface of the cover 106, and / or between pellets and the composite surface 206 of the composite structure 200. By filling such gaps, the expandable medium 130 can provide a substantially smooth finish to the surface of the composite structure 200.

[0095] In various examples, after the portion 202 of the composite structure 200 has cured, the cover 106 can be unsealed, opened, or removed as needed to access the expansion medium 130. While the expansion medium 130 is typically easily removable after the composite structure 200 has cured, in some cases the expansion medium 130 remains expanded and tightly packed after the composite structure 200 has cured and cooled, tending to hinder removal. In such cases, the expansion medium 130 can be additionally configured in one or more ways to make it easier to separate from the composite structure 200, the base 104, and / or the cover 106. As one example, the expansion pellets 136 can be configured to change shape and / or size as needed, thereby making them easier to remove. For example, the expansion pellets 136 can be configured to shrink upon cooling, which causes the expansion pellets 136 to shrink in the interior space 114 after the composite structure 200 has cured and cooled, facilitating removal.

[0096] In one or more examples, the expandable medium 130 is modified to minimize sintering (self-adhesion) upon heating and expansion. Alternatively, or in addition, the expandable medium 130 can be configured to minimize the likelihood of adhesion to surfaces, for example, by coating the expandable pellets 136 with a suitable agent configured to prevent adhesion and / or promote separation.

[0097] In one or more examples, suitable agents for addition to the expandable medium 130 include lubricants. By way of example, adding a lubricant to the expandable pellets 136 can reduce adhesion between the expandable pellets 136 before and / or after volumetric expansion. A suitable lubricant does not interfere with the curing of the composite structure 200 and prevents the expanded pellets 136 from substantially adhering to each other, the containment container 102, or components of the work assembly 250. Suitable lubricants may include liquids, powders, or combinations thereof. When added as a powder, suitable lubricants may include nanopowder. Alternatively, or in addition, 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, perfluoropolyethers (PFPEs), perfluoroalkyl ethers (PFAEs), perfluoropolyalkyl ethers (PFPAEs), and the like. Such lubricants may be applied to the expandable pellets 136 prior to placing the expandable pellets 136 in the containment container 102. Alternatively, or in addition, a suitable lubricant may be applied to the expandable pellets 136 while they are disposed within the containment container 102. Coating at least a portion of the expandable pellets 136 with a suitable lubricant may include mixing the lubricant with multiple pellets and / or pouring the lubricant onto multiple pellets. Additionally, or alternatively, at least a portion of multiple expandable pellets 136 may be coated with a desired lubricant and then mixed with multiple uncoated pellets.

[0098] In one or more examples, the crystallinity and / or semi-crystallinity along the outer surface of the expandable pellets 136 can help prevent the pellets from sintering together. In one or more examples, at least some of the expandable pellets 136 are configured to have crystalline regions along their outer surface, such as by pre-processing, and adding the expandable medium 130 includes adding multiple expandable pellets 136 with highly crystalline surface regions to reduce inter-pellet adhesion before and / or after volumetric expansion of the expandable pellets 136. In one or more examples, expandable pellets 136 can be used when the outer surface of the pellets exhibits a high degree of crystallinity (e.g., when a high percentage of the volume of the pellet near the outer surface has a crystalline structure). Crystallinity in the expandable pellets 136 can be achieved by adjusting 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 pellet temperature is maintained at the manufacturing temperature during manufacturing, the electric and / or magnetic field applied during manufacturing, the distribution of the blowing agent within the pellets, the composition and / or concentration of the blowing agent, etc. The exterior surface of the expandable pellets 136 may be crystalline before, during, and / or after expansion.

[0099] Referring now to FIG. 2 , an example of a method 1000 according to the present disclosure is shown. The method 1000 includes multiple elements, steps, operations, or processes. Not all of the elements, steps, operations, or processes described or illustrated in one example are necessarily required in that example. Some or all of the elements, steps, operations, or processes described or illustrated in one example may be combined in various ways with other examples without necessarily including other elements, steps, operations, or processes described in those other examples. Also, such combinations may not be explicitly described or illustrated in the examples provided herein.

[0100] 1 and 3-10 in general, and with particular reference to FIG. 2, in various examples, method 1000 includes multiple steps, as detailed herein. In one or more examples, method 1000 is implemented using system 100 (FIG. 1).

[0101] In one or more examples, according to the method 1000, the composite structure 200 includes a plurality of composite plies 208. In one or more examples, at least some of the composite plies 208 are in an uncured state. In one or more examples, at least some of the composite plies 208 are in a partially cured state. In one or more examples, at least some of the 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 examples, at least one of the composite plies 208 is a composite patch 214 configured to repair a portion of the composite surface 206 of the composite structure 200.

[0102] In one or more examples, the method 1000 includes a step 1002 of supporting at least a portion 202 of the composite structure 200. In one or more examples, the portion 202 of the composite structure 200 is supported by a base 104, which reinforces the composite structure 200 during the curing process.

[0103] In one or more examples, the method 1000 includes a step 1004 of applying a casting member 156. In one or more examples, the casting member 156 is applied 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 curing the casting member 156. In these examples, the casting member 156 is disposed on the composite surface 206 of at least the portion 202 of the composite structure 200.

[0104] In one or more examples, the method 1000 includes a step 1008 of moving the cover 106 relative to the composite structure 200. The cover 106 is moved into a position suitable to enclose the portion 202 of the composite structure 200 to be locally cured using the system 100.

[0105] In one or more examples, the method 1000 includes a step 1010 of containing the portion 202 of the composite structure 200 in the restraint container 102. As an example, the cover 106 is positioned relative to the portion 202 of the composite structure 200 such that the portion 202 of the composite structure 200 is contained within the interior space 114 of the restraint container 102 (e.g., the cover 106).

[0106] In one or more examples, the method 1000 includes the step 1012 of retaining the cover 106 to the composite structure 200. In one or more examples, the cover 106 is retained to the composite structure 200 using a retainer 120.

[0107] In one or more examples, the method 1000 includes a step 1014 of coupling the cover 106 to the base 104. In one or more examples, the cover 106 and the base 104 are coupled to one another using a retainer 120.

[0108] In one or more examples, the method 1000 includes a step 1016 of adding an expandable medium 130. In one or more examples, the expandable medium 130 is added within the interior space 114 of the cover 106. In one or more examples, the adding step 1016 is performed before the accommodating step 1010. In one or more examples, the adding step 1016 is performed after the accommodating step 1010.

[0109] In one or more examples, the method 1000 includes selectively altering 1018 the interior space 114 formed by the restraint container 102 and the composite structure 200. In one or more examples, the interior space 114 is selectively altered by moving at least one of the walls 112 of the cover 106.

[0110] In one or more examples, the method 1000 includes a step 1020 of altering a property 134 of the expandable medium 130 to expand the expandable medium 130 to a predetermined volume 132 .

[0111] In one or more examples, the method 1000 includes increasing the temperature of the expansion medium 130 to at least the activation temperature 152, for example, in step 1020, which changes the attribute 134 of the expansion medium 130.

[0112] In one or more examples, the method 1000 includes a step 1022 of inflating the expandable medium 130 disposed in the interior space 114. In one or more examples, the interior space 114 is defined by the wall portion 112 of the cover 106 and the composite structure 200. In one or more examples, the interior space 114 is defined by the overlay portion 168 of the cover 106 and the composite structure 200.

[0113] In one or more examples, the method 1000 includes applying 1024 a positive pressure to the composite structure 200. As the expandable medium 130 expands, it fills the interior space 114 and applies a positive pressure to the composite structure 200 and the cover 106.

[0114] In one or more examples, the method 1000 includes detecting 1026 a pressure and / or force applied to the composite structure 200 by the expansion of the expandable medium 130. In one or more examples, the pressure and / or force is detected using the sensor 166. In one or more examples, the method 1000 includes selectively controlling 1028 the pressure and / or force applied to the composite structure 200.

[0115] In one or more examples, the method 1000 includes a step 1030 of curing at least the portion 202 of the composite structure 200. The composite structure 200 is cured by the application of pressure due to the expansion of the expandable medium 130 in the interior space 114. In one or more examples, the composite structure 200 is also cured by the application of heat.

[0116] In one or more examples, the method 1000 includes the step 1032 of removing the inflation medium 130. In one or more examples, the method 1000 includes the step 1034 of removing the cover 106 and other components of the restraint container 102.

[0117] 1 and 3-10, for example, the present disclosure further relates to a composite workpiece 210. Generally, the composite workpiece 210 includes a composite structure 200 that has been locally cured using the system 100 and / or according to the method 1000.

[0118] Referring to FIG. 1 , an example of a composite workpiece 210 according to the present disclosure is shown below. The composite workpiece 210 includes multiple 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 may be combined in various manners with other examples without the need to include other elements, features, and / or components described in those other examples. Also, such combinations may not be explicitly described or illustrated in the examples shown herein.

[0119] In one or more examples, the composite workpiece 210 includes a composite structure 200 having a plurality of composite layers 208. At least a portion 202 (e.g., at least one of the composite layers 208) is in an uncured or partially cured state. The portion 202 of the composite structure 200 is supported by the base 104 of the system 100. The portion 202 of the composite structure 200 is contained within a cover 106 of the system 100. The cover 106 forms or defines at least a portion of the interior space 114 of the restraint container 102. In one or more examples, the cover 106 includes a wall 112 that forms at least a portion of the interior space 114. In one or more examples, the cover 106 includes an overlay 168 that forms at least a portion of the interior space 114. The expandable medium 130 is disposed between the cover 106 and the composite structure 200 in the interior space 114 of the restraint container 102. 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 causing the expansion medium 130 to apply a positive pressure to the composite structure 200 and the cover 106.

[0120] In one or more examples of composite workpiece 210, at least one of composite plies 208 is a composite patch 214. Composite patch 214 is configured to repair a portion of composite surface 206 of composite structure 200 by locally curing the patch using system 100.

[0121] In one or more examples of the composite workpiece 210, 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 a temperature less than, at least equal to, or greater than the cure temperature 212 of the plurality of composite layers 208.

[0122] In various other examples of composite workpiece 210, system 100 includes one or more of the components described herein and / or shown in FIGS. 1 and 3-11.

[0123] The disclosed examples of system 100 and method 1000 are useful for a variety of composite materials used in the manufacture of desired components in any suitable industrial application. The example systems 100 and methods described herein are particularly useful in the manufacture of composite materials without the use of an autoclave, which may be desirable, for example, in manufacturing environments or remote work sites. The example systems 100 and methods 1000 described herein are further useful in the manufacture of components with unique or irregular shapes that cannot be easily processed in an industrial autoclave.

[0124] 11-14, example systems 100 and methods 1000 described herein may relate to or be used in aerospace manufacturing and service methods 1100, as shown in the flow diagram of Figure 13, and aircraft 1200, as shown generally in Figure 14. By way of example, aircraft 1200 and / or manufacturing and service methods 1100 may include or use composite components that use system 100 and / or that have been locally cured or repaired in accordance with method 1000.

[0125] The disclosed system 100 and method 1000 examples can be used in any suitable industry to produce desired composite materials, and although the examples are described in the context of aircraft manufacturing and maintenance, these are illustrative only and are not intended to limit the applicability of the disclosed system and method in any way.

[0126] FIG. 11 illustrates an example of an aircraft 1200. The aircraft 1200 may be any aerospace vehicle or platform. In one or more examples, the aircraft 1200 includes an airframe 1202 having an interior 1206. The aircraft 1200 includes multiple on-board systems 1204 (e.g., high-level systems). Examples of the on-board 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 on-board systems 1204 also include one or more control systems connected to the airframe 1202 of the aircraft 1200. In still other examples, the on-board systems 1204 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.

[0127] Aircraft 1200 may include any number of composite structures, at least a portion of which may be locally stiffened using system 100 and / or according to method 1000. Suitable for the example methods and processes described herein include aircraft components and substructures suitable for composite manufacturing, including, but not limited to, structural parts, fuselage panels, bulkhead sections, etc. In one example, system 100 and method 1000 of the present disclosure are particularly useful in the manufacture and / or repair of stiffeners and stringers used in aircraft manufacturing.

[0128] 11 and 12 , in one or more examples, the aircraft 1200 includes one or more stiffeners 220 configured to support a load. In some examples, the stiffeners 220 are attached to a skin 222 to improve the strength, stiffness, and / or buckling resistance of the skin 222. The stiffeners 220 may be included in any suitable portion of the frame of the aircraft (e.g., the airframe 1202) and / or other suitable portions of the aircraft 1200. FIGS. 11 and 12 show stiffeners 220 stiffening the skin 222 in the example of a wing 224 of the aircraft 1200.

[0129] FIG. 11 illustrates an example of a composite structure 200 in the form of a stiffener 220 (e.g., a composite hat stiffener). In one or more examples, the stiffener 220 includes a cap 232 and a first sidewall 234 and a second sidewall 236 extending from opposite sides of the cap 232. In the illustrated example, the first sidewall 234 and the second sidewall 236 extend from the cap 232 at an obtuse angle. In other examples, the first sidewall 234 and the second sidewall 236 may form an acute angle or a substantially right angle with the cap 232. The angle between the cap 232 and the first sidewall 234 may or may not be equal to the angle between the cap 232 and the second sidewall 236. The cap 232 may be substantially planar or may include curved and / or angled portions. The stiffener 220 also includes a first flange 238 extending from the first sidewall 234 and a second flange 242 extending from the second sidewall 236. The first flange 238 and the second flange 242 extend away from each other in opposite directions and may be parallel to the cap 232 (e.g., the first and second flanges may be coplanar and define a plane parallel to a plane generally defined by the cap). The first flange 238 and the second flange 242 each have a bottom surface attachable to the skin 222, thereby configuring the stiffener 220 to reinforce, stiffen, and strengthen the skin 222. Multiple stiffeners 220 may be attached to a wide range of the skin 222.

[0130] 12 illustrates an example composite structure 200 in the form of a portion of a wing 224 of an aircraft 1200. In various examples, the stiffener 220 is attached to the skin 222 by holding the stiffener 220 and the skin 222 together while curing them, or by separately curing the stiffener 220 and the skin 222 and then fastening the stiffener 220 to the skin 222. In various examples, the stiffener 220 and the skin 222 may each comprise one or more polymeric materials, thermoplastic materials, thermoset materials, and / or other suitable materials, depending on the properties desired in the finished product.

[0131] Composite stiffeners or stringers are often attached to, for example, fuselage sections or wing skins to provide stiffness and strength to the connected aircraft panels while reducing weight. To ensure strength and rigidity, stiffeners may have a concave cross-section with flared sections. Stiffeners may also have a generally curved shape to match the curved surface of the fuselage to which they are connected. Additionally, stiffeners may include one or more bends or joggles to accommodate one or more aircraft systems. Due to these constraints, the resulting stiffener may have a size and shape that makes it difficult to transport into and out of an industrial autoclave, and the uncured stiffener may not fit into an autoclave. However, such composite stiffeners can be easily accommodated by a restraint container 102 sized and shaped to accommodate the stiffener and / or its localized portion. A composite stiffener, whether uncured, partially cured, or to be repaired, can be placed on a rigid mold (e.g., base 104) constructed to define or have a desired cross-sectional profile, curvature, and step in the stiffener. The composite stiffener is then easily cured while placed in the rigid mold by applying the necessary pressure with an appropriate inflatable element (e.g., inflatable medium 130). Similarly, repairs may be required in areas of composite panels forming the fuselage and / or wings. In such cases, repairs are difficult to perform using an autoclave. However, such composite panels can be easily accommodated using a restraining container 102 that can be easily moved to cure the repair area in the fuselage or wing.

[0132] 13 , pre-production manufacturing and service method 1100 of aircraft 1200 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 entry into service 1112. Routine maintenance and service 1114 includes upgrading, reconfiguring, modifying, etc., one or more systems of the aircraft 1200.

[0133] 13 may be performed or implemented by a system integrator, a third party, and / or an operator (e.g., a customer). Note that a system integrator may include, but is not limited to, an aircraft manufacturer and any number of major system subcontractors. A third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers. An operator may be an airline, a leasing company, a military entity, a service organization, etc.

[0134] The example system 100 and method 1000 shown and described herein may be employed at any one or more stages of the manufacturing and service method 1100 shown in the flow diagram of FIG. 13 . For example, at least a portion of a composite structure may be locally cured using the system 100 and / or in accordance with the method 1000 during part and subassembly manufacturing 1106 and / or as part of system integration 1108. Further, at least a portion of a composite structure may be locally cured using the system 100 and / or in accordance with the method 1000 during in-service 1112 of the aircraft 1200. Also, at least a portion of a composite structure may be locally cured using the system 100 and / or in accordance with the method 1000 during system integration 1108 and certification and delivery 1110. Similarly, at least a portion of a composite structure may be locally cured using the system 100 and / or in accordance with the method 1000 during in-service 1112 and maintenance and service 1114 of the aircraft 1200.

[0135] In the above detailed description, reference is made to the accompanying drawings, which illustrate specific embodiments described in the present disclosure. Accordingly, other embodiments having different structure and operation do not depart from the scope of the present disclosure. It should be noted that like reference numerals in different drawings may refer to the same feature, element, or component. Throughout this disclosure, any one of multiple elements may be referred to individually, and multiple elements may be referred to collectively and referred to by like reference numerals. Furthermore, in this specification, a feature, element, component, or step described in the singular should be understood as not excluding multiple features, elements, components, or steps, unless otherwise specified.

[0136] Illustrative, non-exhaustive examples of the subject matter disclosed herein have been provided above, and these examples may include those that are or are not recited in the claims. As used herein, the term "example" means that one or more features, structures, elements, components, features, and / or operational steps described in connection with the example are included in at least one aspect, embodiment, and / or implementation of the subject matter disclosed herein. Thus, in this disclosure, terms such as "one example," "another example," "one or more examples," and similar terms may, but do not necessarily, refer to the same example. Furthermore, features characterizing one example may, but do not necessarily, include features characterizing other examples. Furthermore, features characterizing one example may, but do not necessarily, be combined with features characterizing other examples.

[0137] 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, the term "configured" refers to characteristics that a system, apparatus, structure, article, element, component, or hardware already possesses, characteristics 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.

[0138] Unless otherwise specified, the terms "first," "second," "third," etc. are used merely as labels and do not impose any order, position, or hierarchy requirements on the elements to which these terms 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.

[0139] As used herein, when the phrase "at least one" is used in connection with a list of elements, it 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" could include, but is not limited to, element A, or element A and element B. Also in this example, it could include elements A, element B, and element C, or element B and element C. In other examples, "at least one" could 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 any other suitable combination. As used herein, the phrase "and / or" and the symbol " / " include any and all combinations of one or more of the associated listed elements.

[0140] As used herein, the terms "coupled," "coupled," and similar terms refer to two or more elements being joined, coupled, fixed, attached, connected, in communication with, or otherwise associated with one another (e.g., mechanically, electrically, fluidly, optically, electromagnetically). In various examples, multiple elements may be directly or indirectly associated. For example, element A may be directly associated with element B. Element A may also be indirectly associated with element B through another element C. Note that not all associations between various disclosed elements are necessarily shown. Thus, other associations than those shown may exist.

[0141] As used herein, the term "about" refers to a condition that is not exactly the same as the described condition, but is close to the described condition and is capable of performing a desired function or achieving a desired result. For example, the term "about" refers to a condition that is within an acceptable range of a predetermined tolerance or precision, for example, a condition that is within 10% of the described condition. However, the term "about" does not exclude a condition that is exactly the same as the described condition. As used herein, the term "substantially" refers to a condition that is essentially the same as the described condition and is capable of performing a desired function or achieving a desired result.

[0142] The illustrations of Figures 1, 3-12, and 14 referenced in the foregoing description depict functional elements, features, or components and do not necessarily imply a particular, specific structure. Accordingly, modifications, additions, and / or omissions may be made to the illustrated structures. Additionally, those skilled in the art will recognize that not all elements, features, and / or components shown and described in Figures 1, 3-12, and 14 need be included in every example, and not all described elements, features, and / or components may be shown in each illustrated example. Accordingly, some of the elements, features, and / or components shown and described in Figures 1, 3-12, and 14 may be combined in various ways without including other features shown in Figures 1, 3-12, and 14, other figures, and / or the accompanying disclosure, without such combinations necessarily being expressly stated in this disclosure. Similarly, additional features not limited to the described examples 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, 3-12, and 14 are not intended to imply any architectural limitations on the example embodiments. Rather, they illustrate one example structure, which may be varied as appropriate. Accordingly, modifications, additions, and / or omissions may be made to the illustrated structure. Furthermore, elements, features, and / or components serving similar, or at least substantially similar, purposes are labeled with the same reference numerals in FIGS. 1, 3-12, and 14, and such elements, features, and / or components may not be described in detail with reference to FIGS. 1, 3-12, and 14. Similarly, not all elements, features, and / or components are labeled with reference numerals in FIGS. 1, 3-12, and 14, but the reference numerals associated with these elements may be used in the description for consistency.

[0143] In Figures 2 and 13 referenced in the above description, blocks may represent processes, steps, and / or portions thereof, and lines connecting various blocks do not imply a particular order or dependency of the processes or portions thereof. It should be noted that not all dependencies between the various processes disclosed are necessarily shown. Figures 2 and 13 and the accompanying disclosure describing the processes in the methods described herein do not necessarily dictate the order in which these processes are performed. Rather, one exemplary order is shown, but the order of these processes can be changed as appropriate. Accordingly, the illustrated processes can be modified, added, and / or omitted, and some steps can be performed in a different order or simultaneously. Additionally, one skilled in the art will recognize that not all of the described processes need be performed.

[0144] Furthermore, the use of features, advantages, or similar expressions in this specification does not imply that all features and advantages that can be realized in embodiments of the present disclosure should or are included in a single example. Rather, the description of features and advantages means that a particular feature, advantage, or characteristic described in connection with an example is included in at least one example. Thus, features, advantages, and similar expressions described in this disclosure may or may not refer to the same example.

[0145] The features, advantages, and characteristics of one described embodiment may be combined in any suitable manner in one or more other embodiments. Those skilled in the art will appreciate that the embodiments described herein may be practiced without one or more of the specific features or advantages of a particular embodiment. In some cases, additional features and advantages may be recognized in some embodiments, but these may not be present in all embodiments. Furthermore, while various embodiments of the 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 limited only by the scope of the claims.

[0146] The present disclosure further includes the following notes:

[0147] Clause 1. A containment container (102) including a cover (106) and having an interior space (114), the cover (106) configured to enclose a portion (202) of a composite structure (200); a retainer (120) configured to hold the cover (106) against the composite structure (200); an expandable medium (130) configured to be disposed between the cover (106) and the composite structure (200) in the interior space (114) of the containment container (102).

[0148] Clause 2. The system (100) of clause 1, wherein the cover (106) is movable relative to the composite structure (200).

[0149] Clause 3. The system (100) of clause 1 or 2, wherein the interior space (114) of the cover (106) is selectively variable.

[0150] Appendix 4. The system (100) according to any one of appendices 1 to 3, wherein the cover (106) is heat reflective.

[0151] Appendix 5. The cover (106) includes a plurality of wall portions (112); 5. The system (100) of any one of claims 1 to 4, wherein the plurality of walls (112) are rigid and do not expand.

[0152] Appendix 6. The system (100) described in Appendix 5, wherein at least one of the plurality of wall portions (112) of the cover (106) is movable to change the interior space (114) of the cover (106).

[0153] Appendix 7. The cover (106) includes an overlay portion (168), 5. The system (100) of any one of claims 1 to 4, wherein the overlay portion (168) is flexible and non-expanding.

[0154] Appendix 8. The system (100) of any one of appendices 1 to 7, further comprising a base (104) configured to support the composite structure (200).

[0155] Clause 9. The system (100) of clause 8, wherein the base (104) includes a rigid mold (142).

[0156] Clause 10. The system (100) of clause 9, wherein the rigid mold (142) includes a molding surface (144) that corresponds to the cross-sectional shape (204) of the composite structure (200).

[0157] Clause 11. The system (100) of clause 8 or clause 9, wherein the retainer (120) is configured to be attached to the base (104).

[0158] Clause 12. The system (100) of clause 11, wherein the retainer (120) includes at least one clamp (122).

[0159] Appendix 13. The system (100) of any one of appendices 1 to 10, wherein the retainer (120) includes a robotic manipulator (124).

[0160] Note 14. The cover (106) further includes a periphery (116); A system (100) according to any one of claims 1 to 13, wherein at least a portion of the periphery (116) is configured to contact a composite surface (206) of the composite structure (200).

[0161] Appendix 15. The system (100) of Appendix 14, 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).

[0162] Appendix 16. The system (100) of Appendix 14, wherein a portion of the periphery (116) of the cover (106) is configured to contact a base (104) that supports the composite structure (200).

[0163] Appendix 17. The system (100) of any one of appendices 1 to 16, wherein the cover (106) has a cross-sectional profile (118) corresponding to the cross-sectional shape (204) of the composite structure (200).

[0164] Appendix 18. The system (100) of any one of Appendixes 1 to 17, wherein the expandable medium (130) is configured to expand to a predetermined volume (132) when a predetermined change occurs in a property (134) of the expandable medium (130), thereby causing the expandable medium (130) to apply a positive pressure to the composite structure (200) and the cover (106).

[0165] Appendix 19. The expandable medium (130) includes expandable pellets (136); the expandable pellets (136) are heat activated at an activation temperature (152); 19. The system of claim 18, wherein the expandable pellets are configured to expand when the temperature of the expandable pellets increases to at least the activation temperature.

[0166] Clause 20. The system (100) of clause 19, wherein the activation temperature (152) of the expandable pellets (136) is equal to or less than the curing temperature (212) of the composite structure (200).

[0167] Clause 21. The system (100) of clause 19 or 20, wherein the expandable pellets (136) comprise foamable pellets (138).

[0168] Clause 22. The expandable medium (130) further comprises an encapsulation element (154); 22. The system (100) of any one of claims 19 to 21, wherein the expandable pellet (136) is disposed within the containment element (154).

[0169] Clause 23. Further comprising a casting member (156) disposed between the expandable medium (130) and the composite surface (206) of the composite structure (200); 23. The system (100) of any one of claims 1 to 22, wherein the casting member (156) is configured to harden.

[0170] Clause 24. The system (100) of any one of clauses 1 to 23, further comprising a heater (158) capable of transferring heat to the expandable medium (130).

[0171] Clause 25. The system (100) of clause 24, wherein the heater (158) is configured to be disposed in the interior space (114) together with the expandable medium (130).

[0172] Clause 26. Containing a portion (202) of a composite structure (200) in a restraining container (102); holding a cover (106) of the containment container (102) against the composite structure (200); inflating an expandable medium (130) disposed in an interior space (114) formed by the cover (106) and the composite structure (200); and curing the composite structure (200).

[0173] Clause 27. The method (1000) of clause 26, further comprising moving the cover (106) relative to the composite structure (200).

[0174] Clause 28. The method (1000) of clause 26 or 27, further comprising supporting at least the portion (202) of the composite structure (200) on a base (104).

[0175] Clause 29. The method (1000) of clause 28, further comprising coupling the cover (106) to the base (104).

[0176] Clause 30. Changing the attributes (134) of the expandable medium (130) to expand the expandable medium (130) to a predetermined volume (132); 30. The method (1000) of any one of claims 26 to 29, further comprising applying a positive pressure to the composite structure (200) and the cover (106).

[0177] Clause 31. The method (1000) of Clause 30, further comprising raising the temperature of the expandable medium (130) to at least an activation temperature (152).

[0178] Clause 32. The composite structure (200) includes a plurality of composite layers (208); 32. The method (1000) of any one of appendixes 26-31, wherein at least a portion of the plurality of composite layers (208) is in an uncured or partially cured state.

[0179] Appendix 33. The method (1000) of Appendix 32, 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).

[0180] Appendix 34. The method (1000) of any one of Appendixes 26-33, further comprising selectively altering the interior space (114) formed by the cover (106) and the composite structure (200).

[0181] Clause 35. Disposing a casting member (156) between the expandable medium (130) and a composite surface (206) of the composite structure (200); 35. The method (1000) of any one of claims 26 to 34, further comprising curing the casting member (156).

[0182] Appendix 36. A composite workpiece (210) comprising a composite structure (200) having a plurality of composite layers (208), At least a portion of the plurality of composite layers (208) is in an uncured state; The portion (202) of the composite structure (200) is supported by a base (104); The portion (202) of the composite structure (200) is surrounded by a cover (106) having an interior space (114); an expandable medium (130) disposed in the interior space (114) between the cover (106) and the composite structure (200); The expandable medium (130) is configured to expand to a predetermined volume (132) when a predetermined change occurs in a property (134) of the expandable medium (130), thereby causing the expandable medium (130) to apply a positive pressure to the composite structure (200) and the cover (106).

[0183] Appendix 37. The composite workpiece (210) of Appendix 36, 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).

[0184] Clause 38. The expandable medium (130) includes expandable pellets (136); the expandable pellets (136) are heat activated at an activation temperature (152); 38. The composite workpiece (210) of claim 36 or 37, wherein the activation temperature (152) of the expandable pellets (136) is at least a curing temperature (212) of the plurality of composite layers (208).

Claims

1. a restraint container including a cover and having an interior space, the cover configured to enclose a portion of the composite structure; a retainer configured to hold the cover against the composite structure; an expandable medium configured to be disposed in the interior volume of the restraint container between the cover and the composite structure.

2. The system of claim 1 , wherein the cover is movable relative to the composite structure.

3. The system of claim 1 , wherein the interior space of the cover is selectively variable.

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

5. the cover includes a plurality of walls; The system of claim 1 , wherein the walls are rigid and do not expand.

6. The system of claim 5 , wherein at least one of the walls of the cover is movable to vary the interior space of the cover.

7. the cover includes an overlay portion; The system of claim 1 , wherein the overlay portion is flexible and non-expanding.

8. 10. The system of claim 8, further comprising a base configured to support the composite structure, the base comprising a rigid mold having a molding surface corresponding to a cross-sectional shape of the composite structure. The system of claim 1 .

9. The system of claim 8 , wherein the retainer is configured to be attached to the base and includes at least one clamp.

10. The system of claim 1 , wherein the retainer comprises a robotic manipulator.

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

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

13. 10. The system of claim 1, wherein the expansion medium is configured to expand to a predetermined volume when a predetermined change occurs in an attribute of the expansion medium, whereby the expansion medium applies a positive pressure to the composite structure and the cover.

14. the expandable medium comprises expandable pellets; the expandable pellets are heat activated at an activation temperature; the expandable pellets are configured to expand when a temperature of the expandable pellets is increased to at least the activation temperature; The system of claim 13 , wherein the activation temperature of the expandable pellets is equal to or less than a cure temperature of the composite structure.

15. The system of claim 14 , wherein the expandable pellets comprise foamable pellets.

16. the expandable medium further comprises an encapsulation element; The system of claim 14 , wherein the expandable pellet is disposed within the containment element.

17. a casting member disposed between the expandable medium and the composite surface of the composite structure; The system of claim 1 , wherein the casting member is configured to harden.

18. further comprising a heater capable of transferring heat to the expansive medium; The system of any one of claims 1 to 17, wherein the heater is configured to be disposed in the interior space together with the expansive medium.

19. containing a portion of the composite structure in a restraining container; retaining a cover of the restraint container against the composite structure; inflating an expandable medium disposed in an interior space defined by the cover and the composite structure; and curing the composite structure.

20. The method of claim 19 further comprising moving the cover relative to the composite structure.

21. The method of claim 19 further comprising supporting at least the portion of the composite structure on a base.

22. The method of claim 19 further comprising coupling the cover to the base.

23. modifying an attribute of the expandable medium to expand the expandable medium to a predetermined volume; 20. The method of claim 19, further comprising applying a positive pressure to the composite structure and the cover.

24. 24. The method of claim 23, further comprising raising the temperature of the expandable medium to at least an activation temperature.

25. the composite structure includes a plurality of composite plies; 20. The method of claim 19, wherein at least a portion of the plurality of composite layers are in an uncured or partially cured state.

26. 26. The method of claim 25, wherein at least one of the plurality of composite plies is a composite patch configured to repair a portion of a composite surface of the composite structure.

27. 20. The method of claim 19, further comprising selectively varying the interior space defined by the cover and the composite structure.

28. disposing a casting member between the expandable medium and a composite surface of the composite structure; The method of any one of claims 19 to 26, further comprising: curing the casting member.

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