Method and system for forming a composite stringer assembly

Abstract

Described herein are methods and systems for forming composite stringer assemblies, or more particularly, methods and systems for shaping a composite charge as the stringer assemblies are formed. A system includes a bladder having a bladder core and a bladder skin. The bladder core is formed of a foam material. The bladder skin is formed of a resilient material and surrounds the bladder core. The bladder is positioned on a charge base as the composite stringer assembly is formed. The charge base subsequently becomes a stringer base, such as a fuselage section or a wing skin. A charge cap is then positioned on the bladder and is configured to conform to the bladder. The combination of the bladder skin and the bladder core provides support during the forming operation and subsequently as the stringer assembly cures. In some examples, the bladder core is collapsible so as to remove the bladder from a cavity of the stringer assembly.

Description

Technical Field

[0001] Composite materials have become increasingly popular for a variety of applications, including but not limited to aircraft manufacturing. Specifically, composite materials offer excellent strength-to-weight ratios, which is highly desirable for lightweight applications. For example, in some cases, composite sheets are used to manufacture aircraft fuselages and wings. These composite sheets are reinforced with composite stringers to further improve the overall stiffness of the assembly. Background Technology

[0002] Composite stringers, fuselage sections, and wing skins are typically manufactured as separate components. These individual components are then attached using, for example, fasteners or adhesives. In some cases, the manufacturing steps for some components overlap. For example, stringers, fuselage sections, and / or wing skins are co-cured together. This co-curing operation is also used for attaching these components.

[0003] In either case, the manufacture of composite structures requires complex and precision equipment. Furthermore, the large size of many aircraft components further complicates the manufacturing process and equipment. For example, shaping composite stringers onto composite sheets requires a support structure (e.g., a mandrel). This support structure defines the final shape of the composite stringer. First, the support structure needs to be positioned between the composite stringer and the composite sheet, tightly fitting the two components. However, this support structure needs to be removed later from the cavity formed by the composite stringer and the composite sheet. Using conventional support structures, this removal operation is challenging, especially when the stringers are long. Summary of the Invention

[0004] This document describes methods and systems for forming composite stringer assemblies, or more specifically, for shaping composite charge during the formation of such stringer assemblies. One system includes a capsule having a capsule core and a capsule skin. The capsule core is formed of a foam material. The capsule skin is formed of an elastic material and surrounds the capsule core. When forming the composite stringer assembly, the capsule is positioned above the charge base. The charge base then becomes the stringer base, such as a fuselage section or wing skin. A charge cap is then positioned above and conforms to the capsule. The combination of the capsule skin and the capsule core provides support during the forming operation and subsequently during the curing of the stringer assembly. In some instances, the capsule core is collapsible to allow removal of the capsule from the cavity of the stringer assembly.

[0005] In some instances, the capsule used to shape the composite charge during the formation of the composite stringer assembly includes a capsule core and a capsule skin. The capsule core is formed of a foam material and includes a base surface and a cap-shaped surface. The capsule skin is formed of an elastic material. The capsule skin surrounds the capsule core. At least a portion of the capsule skin contacts, conforms to, and compresses each of the base surface and the cap-shaped surface.

[0006] In some instances, a method of assembling a bladder using a bladder assembly tool that includes a bladder assembly cavity includes: positioning a bladder skin, including an inner skin surface, into the bladder assembly cavity, including a cavity surface. The method further includes: sealing the bladder skin relative to the cavity surface at each end of the bladder assembly tool, and reducing a first pressure between the cavity surface and the bladder skin relative to a second pressure at the inner skin surface, thereby stretching the bladder skin and conforming it to the cavity surface. The method further includes: inserting a bladder core into the bladder skin while it conforms to the cavity surface, and equalizing the first and second pressures, thereby allowing the bladder skin to contract and allowing at least a portion of the bladder skin to conform to the bladder core.

[0007] In some instances, a method of forming a composite stringer assembly from a composite charge using a stringer forming tool including a capsule includes: positioning the capsule above a charge base positioned above a tool base of the stringer forming tool; positioning a charge cap above the capsule, the capsule including a capsule core and a capsule skin; and positioning a flexible cover of the stringer forming tool above the charge cap and sealing the flexible cover relative to the tool base. The method further includes: reducing a first forming pressure between the flexible cover and the tool base to below a second forming pressure at the surface of the outer cover and also below a third forming pressure inside the capsule, thereby forcing the charge cap against the capsule using the flexible cover. The method further includes: solidifying the charge base and the charge cap as the charge cap is forced against the capsule, thereby forming the stringer base and stringer cap of the composite stringer assembly, and removing the capsule from the stringer cavity. Attached Figure Description

[0008] Figure 1A This is a schematic diagram of a composite loading system based on some examples. The composite loading system includes a loading base and a loading cap, and is used to form a composite stringer assembly.

[0009] Figure 1B This is a schematic diagram of a composite stringer assembly based on some examples, which includes a stringer base and a stringer cap and is composed of... Figure 1A The composite material is formed in the process.

[0010] Figure 2A , Figure 2B and Figure 2C This is a schematic cross-sectional view of a capsule used to form a composite charge, based on some examples.

[0011] Figure 3 It is a flowchart of the process of assembling capsules using capsule assembly tools based on some examples.

[0012] Figure 4A , Figure 4B ,and Figure 4C This is a schematic cross-sectional view of a capsule assembly tool when the capsule skin is positioned into the capsule assembly cavity of the tool, based on some examples.

[0013] Figure 5 This is a schematic cross-sectional view of a capsule assembly tool when the capsule skin is sealed relative to the cavity surface, based on some examples.

[0014] Figure 6A , Figure 6B , Figure 6C , Figure 6D , Figure 6E and Figure 6F This is a schematic cross-sectional view of a capsule assembly tool based on some examples, when the capsule skin is stretched and the capsule skin conforms to the cavity surface.

[0015] Figure 7A , Figure 7B and Figure 7C This is a schematic cross-sectional view of a capsule assembly tool used when the capsule skin conforms to the cavity surface, based on some examples, the capsule core is inserted into the capsule skin.

[0016] Figure 8A and Figure 8B This is a schematic cross-sectional view of a capsule assembly tool based on some examples, where the capsule skin conforms to the capsule core.

[0017] Figure 9A and Figure 9B These are schematic cross-sectional views of a capsule assembly tool used to remove a capsule from a capsule assembly tool, based on some examples.

[0018] Figure 10A , Figure 10B and Figure 10C This is a schematic cross-sectional view of an extension of a capsule skin that is sealably coupled to an end fitting, based on some examples.

[0019] Figure 11A and Figure 11B These are schematic cross-sectional views of two examples of bladders with different end fittings, based on some examples.

[0020] Figure 12 This is a flowchart illustrating the process of forming composite stringer assemblies from composite materials using stringer forming tools, based on several examples.

[0021] Figure 13A , Figure 13B , Figure 13C and Figure 13D These are schematic diagrams illustrating different stages in the formation of composite stringers, based on several examples.

[0022] Figure 14 It is a process flow diagram based on some examples corresponding to the methods used to manufacture and maintain aircraft.

[0023] Figure 15 A block diagram of an exemplary aircraft based on some examples is shown. Detailed Implementation

[0024] In the following description, numerous specific details are outlined to provide a comprehensive understanding of the proposed ideas. In some instances, the proposed ideas can be practiced even without some or all of these specific details. In other instances, well-known processing operations have not been described in detail to avoid unnecessarily obscuring the described ideas. While some ideas will be described with specific examples, it will be understood that these examples are not intended to be limiting.

[0025] Introduction

[0026] As mentioned above, the manufacture of composite stringers and components comprising these stringers is challenging and requires sophisticated tooling, especially when the cap stringer is co-formed with the stringer base, or more specifically, co-cured. See now. Figure 1A and Figure 1B Explain these complexities and challenges. Specifically, Figure 1A It is used to form Figure 1B The diagram shows a schematic of the composite loading 180 of the composite stringer assembly 190. The composite loading 180 includes a loading base 182 and a loading cap 181. Although... Figure 1A The composite charge 180 in a formed state is shown, but those skilled in the art will understand that the initial shapes of the charge base 182 and / or charge cap 181 may differ. In some instances, the charge cap 181 is provided as a planar structure, for example, as in... Figure 1A The details are schematically shown in dashed lines. In some instances, the loading base 182 and / or loading cap 181 are formed using a stringer forming tool as described further below. For simplicity, details are not shown in the diagram. Figure 1A and Figure 1B The image shows a sac-like structure.

[0027] Figure 1B This is a schematic diagram of a composite stringer assembly 190 including a stringer base 192 and a stringer cap 191. The stringer cap 191 can also be referred to as a stringer. According to some examples, the composite stringer assembly 190 is composed of... Figure 1AThe composite material 180 is formed. Those skilled in the art will understand that the stringer base 192 is typically part of another component (e.g., a fuselage section or wing skin). The stringer base 192 is formed from the loading base 182 of the composite material 180. The stringer cap 191 is formed from the loading cap 181 of the composite material 180. When the stringer base 192 and stringer cap 191 are formed, these components are also joined together, for example, by co-curing.

[0028] like Figure 1B As shown, stringer base 192 and stringer cap 191 form stringer cavity 193. When forming the composite stringer assembly 190, stringer base 192 and stringer cap 191, or more specifically, loading base 182 and loading cap 181, need to be supported internally (from within stringer cavity 193). This is achieved by positioning a capsule within stringer cavity 193. The capsule conforms to each of stringer base 192 and stringer cap 191. However, once the composite stringer assembly 190 is formed, the capsule needs to be removed from stringer cavity 193. This combination of support, conformation, and removability presents significant challenges to the design and construction of the capsule. For example, conventional capsules are difficult to remove because they retain their shape throughout all processing stages.

[0029] This describes methods and systems for addressing these challenges using specially constructed capsules. Specifically, the capsule includes a capsule core and a capsule skin. The capsule core is formed of a foam material, allowing fluid distribution within the capsule (e.g., causing the capsule to contract during removal). The capsule skin is formed of an elastic material. The capsule skin surrounds the capsule core and isolates the capsule core from the loading cap 181 and the loading base 182. At least a portion of the capsule skin contacts, conforms to, and compresses the surface of the capsule core. In other words, the capsule skin portion is stretched over the capsule core. This stretching ensures the conformability of the capsule skin. Furthermore, the elastic properties of the capsule skin enable the assembly of the capsule. Specifically, the capsule skin is stretched when the capsule core is inserted into the capsule skin. The capsule skin may be referred to as an undersized elastomer sleeve. The capsule core may be referred to as a foam material mandrel.

[0030] Examples of cysts

[0031] Now refer to Figure 2A , Figure 2B and Figure 2C Describe further characteristics and examples of cystic structures. Specifically, Figure 2A A cross-section of the capsule 110 is shown through a plane perpendicular to its length (YZ plane). For the purposes of this disclosure, the length of the capsule 110 extends along the X-axis. Figure 2BAnother cross-section of the capsule 110 is shown through a plane (XZ plane) that includes the length of the capsule 110. Figure 2B Another cross-section of the capsule 110 is also shown through the XZ plane, showing different examples of the end fittings of the capsule 110.

[0032] Reference Figure 2A The capsule 110 includes a capsule core 120 and a capsule skin 130, with the capsule skin surrounding the capsule core 120. Figure 2A The cross section in the middle corresponds to Figure 1A The cross-section of the composite charge 180 in the middle and also corresponding to Figure 1B The cross-section of the composite stringer assembly 190 is shown. More specifically, the contour of the capsule skin 130 (e.g., the contour of the outer skin surface 138 of the capsule skin 130) is the same as the contour of the stringer cavity 193. When the capsule 110 is used to shape the composite charge 180, the capsule skin 130, or more specifically, the outer skin surface 138, contacts the composite charge 180. The capsule core 120 helps to maintain the shape of the capsule skin 130 and thus defines the shape of the composite charge 180.

[0033] In some instances, the capsule core 120 is formed of a foam material 121 (e.g., an open-cell or closed-cell foam material). In some instances, the foam material 121 provides fluid communication within the capsule 110, for example, when the pressure within the capsule 110 decreases. Gas is added to or removed from the capsule 110 to make the capsule 110 more compact, for example, when removing the capsule 110 from the composite stringer assembly 190. This feature is referenced below. Figure 13D Further description. Some examples of suitable foam materials for the capsule core 120 include, but are not limited to, polyethylene terephthalate (PET) foam materials, such as Divinycell P foam material available from Diab Group in Helsingborg, Sweden. In some instances, the foam material 121 is selected such that the capsule core 120 is subjected to full atmospheric pressure at room temperature, but shrinks under vacuum pressure at an elevated curing temperature.

[0034] The capsule core 120 includes a base surface 122 and a cap-shaped surface 124. The base surface 122 defines the shape of the stringer base 192, while the cap-shaped surface 124 defines the shape of the stringer cap 191. In some instances, the base surface 122 is substantially planar. In the same or other instances, the cap-shaped surface 124 is curved. Those skilled in the art will understand that the shape of the cap-shaped surface 124 defines the shape of the stringer cap 191 formed using the capsule 110. Thus, different shapes of the cap-shaped surface 124 fall within this range. In some instances, the contours of the base surface 122 and the cap-shaped surface 124, plus the thickness of the capsule skin 130, are the same as the contour of the stringer cavity 193.

[0035] The capsule skin 130 is formed of an elastic material 131. Some examples of the elastic material 131 include, but are not limited to, silicone, fluorinated rubber, and butyl rubber. In some examples, the wall thickness of the capsule skin 130 is between 1 mm and 5 mm, or more specifically, between 2 mm and 4 mm, such as about 2.5 mm. At least a portion of the capsule skin 130 contacts, conforms to, and compresses each of the base surface 122 and the cap-shaped surface 124 of the capsule core 120. In some examples, the capsule skin 130 is stretched over the capsule core 120 by at least about 1%, at least about 2%, at least about 5%, and at least about 10%, or even at least about 20%. The stretching of the capsule skin 130 helps to conform the capsule skin 130 to the capsule core 120 without any wrinkles or other defects. However, this stretching also compresses the capsule core 120, and excessive compression may affect the shape of the capsule core 120. Therefore, overstretching (e.g., more than 50%) should be avoided.

[0036] refer to Figure 2B and Figure 2C In some instances, the capsule skin 130 includes one or two extensions, such as extension 133 and a second extension 134. The extensions of the capsule skin 130 extend through the capsule core 120 but do not contact the capsule core 120. The remaining portion of the capsule skin 130 contacts the capsule core 120, for example, conforming to and compressing the capsule core 120. In some instances, the extensions are used to, for example, form a fluid connection to the capsule 110, or more specifically, a fluid connection to the interior of the capsule 110 and the capsule core 120. Specific examples include... Figure 2B and Figure 2C Extension 133 and Figure 2C The second extension 134. In the same or other examples, the extension is used to seal the end of the capsule 110, such as, Figure 2B The second extension 134 in the middle.

[0037] refer to Figure 2B and Figure 2CIn some instances, the capsule 110 also includes an end fitting 140 that is hermetically connected to an extension 133 of the capsule skin 130. In some instances, the end fitting 140 includes a through-hole 145 that is flowably coupled to the capsule core 120. The through-hole 145 is used to supply gas to or remove gas from the interior of the capsule 110. For example, removing gas from the interior can reduce the size of the capsule skin 130 and cause the capsule core 120 to contract, as described below. Figure 13D Further description. In some instances, the through-hole 145 may be selectively coupled to the atmosphere or a vacuum source 109.

[0038] See Figure 2B and Figure 2C In some instances, the end fitting 140 includes a first component 141 and a second component 142. The second component 142 is detachably coupled to the first component 141, for example, using a screw 144. In a more specific instance, the second component 142 forms a channel 143 between the first component 141 and the second component 142. An extension 133 of the capsule skin 130 surrounds, conforms to, and compresses the first component 141 and extends partially into the channel 143. More specifically, the extension 133 utilizes the channel 143 to compress between the first component 141 and the second component 142 to ensure a seal of the capsule skin 130 relative to the end fitting 140, as referenced below. Figure 10A , Figure 10B and Figure 10C Further description.

[0039] refer to Figure 2B and Figure 2C In some instances, the first component 141 and the second component 142 are detachably coupled using a screw 144. This detachable coupling allows the extension 133 to be positioned on the first component 141 before the second component 142 is connected, thereby simplifying the overall assembly of the capsule 110. In a more specific instance, a through-hole 145 extends through the screw 144. This feature allows the through-hole 145 to be added or removed by replacing the screw 144 (e.g., a screw with the through-hole 145 and a screw without the through-hole 145).

[0040] refer to Figure 2B and Figure 2C In some instances, the capsule skin 130 includes a second extension 134 that extends beyond the capsule core 120 and away from the extension 133. The capsule core 120 is located between the extension 133 and the second extension 134. The second extension 134 allows for fluid connection to or sealing of the capsule 110 to this side of the capsule 110. For example, Figure 2BA sealed and airtight second extension 134 is shown. More specifically, in this example, the bladder 110 includes a second end fitting 150 that is sealably coupled to the second extension 134 of the bladder skin 130 and prevents fluid from entering the bladder core 120 from at least this side of the second extension 134.

[0041] refer to Figure 2C In some instances, the second end fitting 150 includes a second fitting through-hole 155 that is flowably coupled to the capsule core 120. For example, the second fitting through-hole 155 passes through a second screw 154. Replacing the second screw 154 allows for... Figure 2B One structure of the sac-like structure 110 shown is switched to Figure 2C Another configuration of the sac-like structure 110 shown.

[0042] In some instances, the design of the second end fitting 150 is identical to that of the end fitting 140. For example, the second end fitting 150 includes two components, one of which is hermetically coupled to the second extension 134. Furthermore, the two components are detachably coupled to each other. Finally, when the two components are attached, a portion of the second extension 134 extends and compresses between the two components.

[0043] Examples of methods for assembling capsules

[0044] Figure 3 This is a process flow diagram corresponding to method 200 for assembling capsule 110, based on some examples. (See above references...) Figure 2A-2C Various instances of the capsule 110 are described. Different operations of method 200 are performed using the capsule assembly tool 300. The key features of the capsule assembly tool 300 are described below with reference to specific operations. Furthermore, as shown below... Figures 4A-11B The various stages of method 200 are shown in the figure.

[0045] In some instances, method 200 begins (box 210) by positioning the capsule skin 130 into the capsule assembly cavity 312 of the capsule assembly tool 300, for example, as in Figure 4A , Figure 4B and Figure 4CThe diagram is schematically shown. At this stage, the capsule skin 130 does not conform to the capsule assembly cavity 312, thus allowing for simple insertion of the capsule skin 130. Specifically, the capsule skin 130 includes an inner skin surface 137 and an outer skin surface 138. The capsule skin 130 is not stretched or positioned on the capsule core 120 at this stage. The capsule assembly cavity 312 includes a cavity surface 313. The outer skin surface 138 of the capsule skin 130 does not conform to the cavity surface 313, which makes this operation possible. Referring to the cross-section of the capsule skin 130 and the capsule assembly tool 300, the perimeter of the outer skin surface 138 is shorter than that of the cavity surface 313.

[0046] In some instances, method 200 proceeds (box 220) to seal the capsule skin 130 relative to the cavity surface 313. It should be noted that the capsule skin 130 is sealed at each end 301 of the capsule assembly tool 300. Various sealing options fall within this range. For example, Figure 5 A wedge 320 inserted into a capsule skin 130 is shown. Specifically, in this example, the sealing operation includes (frame 222) inserting the wedge 320 into the capsule skin 130, thereby pushing the capsule skin 130 against the cavity surface 313. The wedge 320 stretches a portion of the capsule skin 130. It should be noted that the wedge 320 includes a wedge through-hole 322. The minimum cross-section of the wedge through-hole 322 is larger than the corresponding cross-section of the capsule core 120, which allows the capsule core 120 to be inserted into the capsule skin 130 through the wedge through-hole 322.

[0047] In some instances, method 200 continues (box 230) by reducing the first pressure between the cavity surface 313 and the capsule skin 130 relative to the second pressure at the inner skin surface 137. This pressure difference (between the first and second pressures) causes the capsule skin 130 to stretch and push against the cavity surface 313, for example, as... Figures 6A-6B This is shown schematically. More specifically, the capsule skin 130 conforms to the cavity surface 313. This stretching of the capsule skin 130 allows the capsule core 120 to be inserted into the capsule skin 130 without interference. At this stage, the cross-section of the inner skin surface 137 is larger than the cross-section of the capsule core 120 (shown schematically in dashed lines). It should be noted that the capsule skin 130 remains sealed relative to the cavity surface 313, which allows for a reduction in the first pressure. In some instances, reducing the first pressure involves connecting the capsule assembly tool 300 to a vacuum source. In other words, the first pressure is below atmospheric pressure. The second pressure is at atmospheric pressure, for example, the interior of the capsule skin 130 is vented to the atmosphere.

[0048] refer to Figure 6C and Figure 6D In some instances, the capsule assembly tool 300 includes a plurality of internal protrusions 314 that extend into the capsule assembly cavity 312 and away from the cavity surface 313. The internal protrusions 314 help maintain fluid channels 315 between the cavity surface 313 and the capsule skin 130 when the capsule skin 130 conforms to the cavity surface 313. These fluid channels 315 are formed around the internal protrusions 314, for example as... Figure 6D As schematically shown, the capsule skin 130 conforms to the cavity surface 313. These fluid channels 315 ensure that all capsule skins 130 (along the length of the capsule, X-axis) are under a second pressure and conform to the cavity surface 313 due to the pressure differential. Reference Figure 6E and Figure 6F In some instances, the capsule assembly tool 300 includes, for example, a fluid channel 315 formed within the cavity surface 313.

[0049] In some instances, method 200 continues (box 240) by inserting the capsule core 120 into the capsule skin 130, for example, as Figures 7A-7C As schematically shown. This operation is performed when the capsule skin 130 conforms to the cavity surface 313 (e.g., by maintaining a pressure difference on the capsule skin 130 and using that pressure difference to push the capsule skin 130 against the cavity surface 313). Figure 7B The cross-section of the inner skin surface 137 is shown to be larger than the cross-section of the capsule core 120, thereby allowing unobstructed insertion.

[0050] In some instances, inserting the capsule core 120 into the capsule skin 130 includes (frame 242) such that the capsule core 120 protrudes through the wedge-shaped through-hole 322, for example, as Figure 7C As schematically illustrated, the wedge 320, as described above, is used to seal the capsule skin 130 relative to the cavity surface 313. This seal is maintained when the capsule core 120 is inserted into the capsule skin 130. Furthermore, as described above, the minimum cross-section of the wedge-shaped through-hole 322 is larger than the corresponding cross-section of the capsule core 120, which allows the capsule core 120 to be inserted into the capsule skin 130 through the wedge-shaped through-hole 322.

[0051] In some instances, method 200 continues (box 250), for example, by equalizing the first and second pressures to atmospheric pressure levels. This pressure equality allows the capsule skin 130 to contract and also allows a portion of the capsule skin 130 to conform to the capsule core 120, for example, as... Figures 8A-8BThis is schematically illustrated. More specifically, this pressure equality eliminates the pressure differential that previously stretched the capsule skin 130. The capsule skin 130 is compressed toward its original form. However, in some instances, when the capsule skin 130 conforms to the capsule core 120, the capsule skin 130 remains partially stretched, with at least a portion of the capsule skin 130 contacting the capsule core 120. In some instances, the stretch level on the capsule core 120 is at least about 1%, at least about 2%, at least about 5%, and at least about 10%. After this operation, the cross-sectional shape of the cavity surface 313 corresponds to the cross-sectional shape of the capsule core 120. Furthermore, at this point, the combination of the capsule skin 130 and the capsule core 120 can be removed from the capsule assembly tool 300.

[0052] In some instances, method 200 further includes (box 258) removing the cyst 110 from the cyst assembly tool 300, for example, as Figure 9A and Figure 9B This is shown schematically. The operation is performed after the capsule skin 130 partially conforms to the capsule core 120 and the capsule skin 130 but not to the cavity surface 313. Therefore, there is no interference between the capsule skin 130 and the cavity surface 313, thereby allowing the capsule 110 to be removed from the capsule assembly cavity 312. Figure 9B The cyst 110 is shown after the removal operation is completed. For example, the cyst skin 130 includes an extension 133 extending through the cyst core 120 and a second extension 134.

[0053] In some instances, method 200 further includes (box 260) hermetically coupling the end fitting 140 to an extension 133 of the capsule skin 130, for example, as Figures 10A-10C This is shown schematically. Specifically, the extension 133 extends through the capsule core 120 such that the capsule core 120 does not interfere with the end fitting 140. For example, the extension 133 is wrapped around the end fitting 140 and conforms to the end fitting.

[0054] In some instances, the end fitting 140 includes a first component 141 and a second component 142. In these instances, hermetically coupling the end fitting 140 to the extension 133 includes (frame 262) inserting the first component 141 into the extension 133 of the bladder skin 130, and also includes (frame 264) attaching the second component 142 to the first component 141. In some instances, the execution is performed by… Figure 3The operations indicated by boxes 262 and 264 cause a portion of the extension 133 of the capsule skin 130 to extend into the channel 143 between the first component 141 and the second component 142. More specifically, this portion of the extension 133 is compressed within the channel 143 by the first component 141 and the second component 142, for example, as... Figure 10C As illustrated in the diagram. See also some examples and... Figure 3 In frame 264, screw 144 is used to attach the second part 142 to the first part 141. More specifically, through hole 145 extends through screw 144.

[0055] In some instances, method 200 also includes (box 270) a second extension 134 of sealing the capsule skin 130, for example, as Figure 11A As schematically shown. The second extension 134 extends through the capsule core 120 and away from the extension 133, such that the capsule core 120 is positioned between the extension 133 and the second extension 134.

[0056] In some instances, method 200 further includes (box 280) hermetically coupling the second end fitting 150 to the second extension 134 of the capsule skin 130, for example, as Figure 11B As schematically shown. The second end fitting 150 includes a second fitting through-hole 155 that is flowably coupled to the capsule core 120. Furthermore, the end fitting 140 includes a through-hole 145 that is flowably coupled to the capsule core 120.

[0057] Examples of methods for forming composite stringers

[0058] Figure 12 This is a process flow diagram corresponding to a method 600 for forming a composite stringer assembly 190 according to some embodiments. The composite stringer assembly 190 is formed from a composite feedstock 180 using a stringer forming tool 100. See above. Figure 1A and Figure 1B Various examples of the composite loading 180 and the composite stringer assembly 190 are described. In some examples, the stringer forming tool 100 includes a capsule 110, as described above. Figures 2A-11B Various examples of cysts are described.

[0059] In some instances, method 600 includes (box 610) positioning the capsule 110 on the filling base 182, for example, as Figure 13AThe diagram is schematically shown. The loading base 182 is part of the composite loading 180 and is positioned on the tool base 102 of the stringer forming tool 100. In some instances, the loading base 182 is substantially planar. The capsule 110 is shaped according to the design of the composite stringer assembly 190. As described above, the capsule 110 includes a capsule core 120 and a capsule skin 130. The capsule core 120 defines the shape, while the capsule skin 130 encloses the capsule core 120 and contacts the loading base 182.

[0060] In some instances, method 600 continues (box 620) by positioning the filling cap 181 onto the capsule 110, for example, as Figure 13B As illustrated schematically. For example, during this operation, the filling cap 181 at least partially conforms to the capsule 110. In some instances, during this forming operation, the filling cap 181 is initially provided as a planar component and then formed around the capsule 110 while the capsule 110 retains its shape.

[0061] In some instances, method 600 continues (block 630) by positioning the flexible cover 104 of the stringer forming tool 100 on the loading cap 181 and sealing the flexible cover 104 relative to the tool base 102, for example, as Figure 13C As schematically shown. This seal allows for reduced pressure between the flexible cover 104 and the tool base 102, for example, to apply external pressure (through the atmosphere) and to conform the filling cap 181 to the bladder 110. In some instances, the filling cap 181 includes a cap tip 183 that directly contacts the filling base 182.

[0062] In some instances, method 600 continues (box 640) by reducing the first forming pressure between the flexible cover 104 and the tool base 102, for example, as in Figure 13C As schematically shown, the first forming pressure decreases to below the second forming pressure at the surface 105 of the outer cover. This pressure difference forces the flexible cover 104 and the filling cap 181 toward the bladder 110, thereby causing the filling cap 181 to conform to the bladder 110.

[0063] Furthermore, in some instances, the first formation pressure is also reduced to below the third formation pressure inside the cyst 110, for example, as... Figure 13C The third pressure helps the capsule 110 maintain its shape when the filling cap 181 is forced against the capsule 110. In some instances, each of the second and third forming pressures is at atmospheric pressure, for example, the corresponding structure is exposed to the atmosphere.

[0064] In some instances, method 600 continues (box 650) to solidify the charge base 182 and the charge cap 181. For example, Figure 13C The entire assembly shown is placed in an autoclave, oven, or other similar apparatus. The curing operation is performed while the loading cap 181 is forced against the capsule 110. Furthermore, the capsule 110 retains its shape during this curing operation. The curing operation forms the stringer base 192 and stringer cap 191 of the composite stringer assembly 190. The stringer base 192 and stringer cap 191 are rigid structures and do not require further support via the capsule 110. Therefore, the capsule 110 can be removed from the stringer cavity 193 after curing.

[0065] In some instances, method 600 continues (box 660) by removing the capsule 110 from the stringer cavity 193. More specifically, removing the capsule 110 from the stringer cavity 193 includes (box 662) reducing a first removal pressure inside the capsule 110. The first removal pressure is reduced to below a second removal pressure inside the stringer cavity 193. This pressure difference compresses the capsule 110 and separates the capsule 110 from the stringer base 192 and the stringer cap 191, for example, as Figure 13D This is illustrated schematically. In some instances, the second removal pressure is atmospheric pressure.

[0066] In some instances, method 600 continues (box 670) by replacing the capsule core 120 of capsule 110. For example, the capsule core 120 is contracted when capsule 110 is removed from stringer cavity 193 and no longer has the desired shape. The process for the capsule core 120 is similar to that described above. Figures 3-11B The process of assembling the capsule 110.

[0067] Aircraft examples

[0068] In some instances, the methods and systems described above are used in aircraft, and more generally in the aerospace industry. Specifically, these methods and systems can be used during aircraft manufacturing as well as during aircraft repair and maintenance.

[0069] Therefore, the apparatus and method described above are applicable to applications such as... Figure 14 The aircraft manufacturing and maintenance methods 900 and as shown Figure 15 The aircraft 902 is shown. During pre-production, method 900 includes the specification and design 904 of the aircraft 902 and material procurement 906. During production, the manufacturing of components and sub-assemblies of the aircraft 902 and system integration 910 are carried out. Subsequently, the aircraft 902 is certified and delivered 912 for service 914. During customer service, the aircraft 902 is used for routine maintenance and repair 916 (which may also include modifications, reconfigurations, refurbishments, etc.).

[0070] In some instances, each process of Method 900 is performed or implemented by a systems integrator, a third party, and / or an operator (e.g., a customer). For the purposes of this specification, a systems integrator may include, but is not limited to, any number of aircraft manufacturers and major systems subcontractors; a third party may include, but is not limited to, any number of contractors, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, etc.

[0071] like Figure 15 As shown, an aircraft 902 produced by method 900 includes a fuselage 918 having multiple systems 920 and an interior 922. The fuselage 918 includes the wings of the aircraft 902. Examples of systems 920 include one or more of a propulsion system 924, an electrical system 926, a hydraulic system 928, and an environmental system 930. Any number of other systems may be included.

[0072] The apparatus and methods presented herein may be employed during any one or more stages of method 900. For example, a component or sub-assembly corresponding to manufacturing 908 may be made or manufactured in a manner similar to that of a component or sub-assembly produced when aircraft 902 is put into service. Moreover, one or more instances of apparatus, method examples, or combinations thereof may be utilized during manufacturing 908 and system integration 910, for example, by significantly accelerating the assembly of aircraft 902 or reducing the cost of aircraft 902. Similarly, one or more instances of apparatus, method examples, or combinations thereof may be used when aircraft 902 is put into service, for example, but not limited to maintenance and repair 916.

[0073] Other examples

[0074] Furthermore, this disclosure includes examples pursuant to the following provisions:

[0075] Clause 1. A capsule for shaping composite charge during the formation of a composite stringer assembly, the capsule comprising:

[0076] The capsule-shaped core is formed of foam material and includes a base surface and a cap-shaped surface; and

[0077] The capsule skin is formed of an elastic material, wherein the capsule skin surrounds the capsule core, and wherein at least a portion of the capsule skin contacts, conforms to, and compresses each of the base surface and the cap-shaped surface.

[0078] Clause 2. The sac pursuant to Clause 1, wherein the sac skin includes an extension extending through the sac core.

[0079] Clause 3. The capsule according to Clause 2 also includes an end fitting that is hermetically coupled to an extension of the capsule skin, the end fitting including a through-hole that is flowably coupled to the capsule core.

[0080] Clause 4. The capsule according to Clause 3, wherein the through-hole may be selectively coupled to an atmospheric or vacuum source.

[0081] Clause 5. The sac-like structure pursuant to Clause 3, wherein,

[0082] The end fitting includes a first component and a second component, the second component being detachably coupled to the first component and forming a channel with the first component, and

[0083] The extension of the sac-like skin surrounds, conforms to, and compresses the first component, and extends partially into the channel, where the extension is compressed between the first and second components.

[0084] Clause 6. The capsule of Clause 5, wherein the first and second components are detachably coupled by screws such that a through-hole extends through the screws.

[0085] Clause 7. The method according to any one of Clauses 2-6, wherein the capsule skin includes a second extension that extends through and away from the capsule core, such that the capsule core is positioned between the extension and the second extension.

[0086] Clause 8. The sac-like structure pursuant to Clause 7, wherein the second extension is sealed and airtight.

[0087] Clause 9. The capsule according to Clause 7 further includes a second end fitting that is hermetically coupled to a second extension of the capsule skin, the second end fitting including a second fitting through-hole that is flowably coupled to the capsule core.

[0088] Clause 10. The capsule as described in Clause 1, wherein the foam material of the capsule core comprises polyethylene terephthalate foam material.

[0089] Clause 11. A capsule according to any one of Clauses 1-10, wherein the elastic material of the capsule skin comprises one or more materials selected from the group consisting of silicone, fluorinated rubber and butyl rubber.

[0090] Clause 12. A sac according to any one of Clauses 1-11, wherein the sac skin is stretched at least about 5% over the sac core.

[0091] Clause 13. A method of assembling a capsule using a capsule assembly tool, the capsule assembly tool including a capsule assembly cavity, the method comprising:

[0092] Position the capsule skin, including the inner skin surface, within the capsule assembly cavity, including the cavity surface;

[0093] Seal the capsule skin relative to the cavity surface at each end of the capsule assembly tool;

[0094] The second pressure relative to the inner skin surface reduces the first pressure between the cavity surface and the capsule skin, thereby stretching the capsule skin and causing the capsule skin to conform to the cavity surface.

[0095] When the capsule skin conforms to the cavity surface, the capsule core is inserted into the capsule skin; and

[0096] The first pressure and the second pressure are made equal, thereby allowing the capsule skin to contract and allowing at least a portion of the capsule skin to conform to the capsule core.

[0097] Clause 14. The method according to Clause 13, wherein the second pressure is maintained at atmospheric pressure level.

[0098] Clause 15. The method according to any one of Clauses 13-14, wherein the cross-sectional shape of the cavity surface corresponds to the cross-sectional shape of the core of the capsule.

[0099] Clause 16. The method according to any one of Clauses 13-15, wherein,

[0100] The sealing of the cavity surface with a bladder-like skin involves inserting a wedge-shaped member into the bladder-like skin, thereby pushing the bladder-like skin against the cavity surface.

[0101] The wedge includes a wedge-shaped through hole, and

[0102] Inserting the core of the capsule into the capsule skin includes making the core of the capsule protrude through the wedge-shaped through-hole.

[0103] Clause 17. The method according to any one of Clauses 13-16 further includes sealingly coupling the end fitting to an extension of the bladder skin.

[0104] The end fitting includes a through-hole that is fluidly coupled to the core of the capsule, and

[0105] The extension extends through the core of the capsule.

[0106] Clause 18. The method according to Clause 17, wherein the end fitting comprises a first component and a second component, and

[0107] The sealing coupling of the end fitting to the extension includes:

[0108] Insert the first component into the extension of the sac-like skin, and

[0109] The second component is attached to the first component such that a portion of the extension of the sac-like skin extends into the channel between the first and second components and is compressed within the channel by the first and second components.

[0110] Clause 19. The method according to Clause 18, wherein a screw is used to attach the second component to the first component such that a through hole extends through the screw.

[0111] Clause 20. The method according to Clause 17 also includes a second extension of the sealing capsule skin.

[0112] The second extension extends through the core of the capsule and away from the extension, such that the core of the capsule is positioned between the extension and the second extension.

[0113] Clause 21. The method according to Clause 17 further includes sealingly coupling the second end fitting to a second extension of the bladder skin.

[0114] The second end fitting includes a second fitting through-hole that is fluidly coupled to the core of the capsule, and

[0115] The end fitting includes a through-hole that is fluidly coupled to the core of the capsule.

[0116] Clause 22. The method according to any one of Clauses 13-21, wherein the capsule assembly tool includes an internal protrusion that extends into and away from the surface of the capsule assembly cavity.

[0117] Clause 23. The method according to any one of Clauses 13-22 further includes removing the bladder from the bladder assembly tool after the bladder skin has partially conformed to the bladder core.

[0118] Clause 24. The method according to any one of Clauses 13-23, wherein, when the first pressure is reduced, the bladder skin stretches by at least 5%.

[0119] Clause 25. A method for forming a composite stringer assembly from a composite load using a stringer forming tool including a capsule, the method comprising:

[0120] Position the capsule on the loading base, which is positioned on the tool base of the stringer forming tool;

[0121] Position the filling cap on the bladder, which includes a bladder core and a bladder skin;

[0122] Position the flexible cover of the stringer forming tool on the loading cap and seal the flexible cover relative to the tool base;

[0123] The first forming pressure between the flexible cover and the tool base is reduced to a level lower than the second forming pressure at the surface of the outer cover and also lower than the third forming pressure inside the bladder, thereby using the flexible cover to force the filling cap against the bladder.

[0124] When the filling cap is forced against the capsule, the filling base and the filling cap solidify, thereby forming the stringer base and stringer cap of the composite stringer assembly, which together form the stringer cavity; and

[0125] Remove the bladder from the stringer cavity.

[0126] Clause 26. The method according to Clause 25, wherein removing the bladder from the stringer cavity comprises: reducing a first removal pressure inside the bladder to below a second removal pressure inside the stringer cavity, thereby compressing the bladder and separating the bladder from the stringer base and stringer cap.

[0127] Clause 27. The method according to Clause 26, wherein the second removal pressure is atmospheric pressure.

[0128] Clause 28. The method according to Clause 26 also includes replacing the core of the sac.

[0129] Clause 29. The method according to any one of Clauses 25-28, wherein the second formation pressure and the third formation pressure are both atmospheric pressure.

[0130] Clause 30. The method according to any one of Clauses 25-29, wherein the filling cap includes a cap end that directly contacts the filling base.

[0131] in conclusion

[0132] Although the foregoing concept has been described in some detail for the purpose of clarity, it will be apparent that certain variations and modifications can be practiced within the scope of the appended claims. It should be noted that many alternative ways of implementing the process, system, and apparatus exist. Therefore, this example is intended to be exemplary rather than limiting.

Claims

1. A capsule for shaping composite charge during the formation of a composite stringer assembly, the capsule comprising: A capsule-shaped core, the capsule-shaped core being formed of foam material and including a base surface and a cap-shaped surface; A capsule-shaped skin, the capsule-shaped skin being formed of an elastic material, wherein the capsule-shaped skin surrounds the capsule-shaped core, wherein at least a portion of the capsule-shaped skin contacts, conforms to, and compresses each of the base surface and the cap-shaped surface, and wherein the capsule-shaped skin includes a first extension extending through the capsule-shaped core; and An end fitting, the end fitting being hermetically coupled to a first extension of the capsule skin, the end fitting including a through-hole fluidly coupled to the capsule core, and wherein: the end fitting includes a first component and a second component, the second component being detachably coupled to the first component and forming a channel with the first component, and wherein: the first extension of the capsule skin surrounds, conforms to, and compresses the first component, and the first extension partially extends into the channel, in which the first extension is compressed between the first component and the second component, wherein the first component and the second component are detachably coupled using a screw such that the through-hole extends through the screw.

2. The capsule-like structure according to claim 1, wherein, The through-hole can be selectively coupled to an atmospheric or vacuum source.

3. The capsule-like structure according to claim 1, wherein, The capsule skin includes a second extension that extends through the capsule core and away from the extension, such that the capsule core is positioned between the extension and the second extension.

4. The capsule-like structure according to claim 3, wherein, The second extension is sealed and airtight.

5. The capsule of claim 3, further comprising a second end fitting, the second end fitting being hermetically coupled to the second extension of the capsule skin, the second end fitting including a second fitting through-hole fluently coupled to the capsule core.

6. The capsule according to claim 1, wherein, The foam material in the core of the capsule includes polyethylene terephthalate foam material.

7. The capsule according to claim 1, wherein, The elastic material of the capsule skin includes one or more materials selected from the group consisting of silicone, fluorinated rubber and butyl rubber.

8. The capsule according to claim 1, wherein, The capsule skin is stretched at least 5% over the capsule core.

9. A method for assembling a capsule using a capsule assembly tool, the capsule assembly tool comprising a capsule assembly cavity, wherein, The method includes: Position the capsule skin, including the inner skin surface, within the capsule assembly cavity, including the cavity surface; The capsule skin is sealed relative to the cavity surface at each end of the capsule assembly tool; The second pressure relative to the inner skin surface reduces the first pressure between the cavity surface and the capsule skin, thereby stretching the capsule skin and causing the capsule skin to conform to the cavity surface; When the capsule skin conforms to the cavity surface, the capsule core is inserted into the capsule skin; The first pressure and the second pressure are made equal, thereby allowing the capsule skin to contract and allowing at least a portion of the capsule skin to conform to the capsule core; and The end fitting is hermetically coupled to an extension of the capsule skin, wherein the end fitting includes a through-hole that is flowably coupled to the capsule core, and wherein the extension extends through the capsule core.

10. The method according to claim 9, wherein, The second pressure is maintained at atmospheric pressure level.

11. The method according to claim 9, wherein, The cross-sectional shape of the cavity surface corresponds to the cross-sectional shape of the core of the capsule.

12. The method according to claim 9, wherein, Sealing the capsule skin relative to the cavity surface includes inserting a wedge into the capsule skin, thereby pushing the capsule skin against the cavity surface. The wedge-shaped member includes a wedge-shaped through hole, and Inserting the core of the capsule into the capsule skin includes allowing the core of the capsule to protrude through the wedge-shaped through-hole.

13. The method according to claim 9, wherein, The end fitting includes a first component and a second component, and Specifically, sealingly coupling the end fitting to the extension includes: Insert the first component into the extension of the skin of the sac-like structure, and The second component is attached to the first component such that a portion of the extension of the sac-like skin extends into the channel between the first component and the second component and is compressed in the channel by the first component and the second component.

14. The method of claim 9, further comprising: The second extension of the skin of the sac-like structure is sealed. The second extension extends through the core of the capsule and away from the extension, such that the core of the capsule is positioned between the extension and the second extension.

15. The method according to claim 9, wherein, The capsule assembly tool includes an internal protrusion that extends into the capsule assembly cavity and away from the cavity surface.

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