Composite pressure hull and methods of forming

Abstract

To provide a composite pressure hull and methods of forming the composite pressure hull.SOLUTION: A composite pressure hull and methods of forming the composite pressure hull are presented. A unitary first half of the composite pressure hull is laid up. A unitary second half of the composite pressure hull is laid up. The unitary first half is joined to the unitary second half to form the composite pressure hull.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 584,684, entitled "Composite Pressure Hull and Methods of Forming," filed Sep. 22, 2023, which is incorporated by reference in its entirety.

[0002] The present disclosure relates generally to composite manufacturing, and more specifically, to the manufacturing of composite pressure hulls. [Background technology]

[0003] Weight reduction is a concern for the storage, manufacturing, or transportation of various structures. Weight can also affect the performance and structural efficiency of some composite structures. For example, it is desirable to reduce the weight of aircraft components, such as fuel tanks. To reduce the weight of components, such as pressure tanks, it may be desirable to manufacture the components from composite materials.

[0004] A composite material is a strong, lightweight material created by combining two or more functional components. For example, a composite material may include reinforcing fibers bound within a polymer resin matrix. The fibers can take the form of unidirectional tapes, woven or woven fabrics, or braids. The mechanical and other material properties of a composite material may be desirable for some implementations. For example, the buoyancy of a composite material may be more desirable for submersible applications. Summary of the Invention [Problem to be solved by the invention]

[0005] It would therefore be desirable to have a method and apparatus that takes into account at least some of the problems discussed above, as well as other possible problems. [Means for solving the problem]

[0006] One embodiment of the disclosure provides a method of forming a composite pressure hull: A one-piece first half of the composite pressure hull is laid up; A one-piece second half of the composite pressure hull is laid up; The one-piece first half is joined to the one-piece second half to form the composite pressure hull.

[0007] Another embodiment of the present disclosure provides a method of forming a composite pressure hull. A dome ply and a cylindrical ply are laid up on a mandrel to form a unitary first half of the composite pressure hull. A second dome ply and a second cylindrical ply are laid up on the mandrel to form a unitary second half of the composite pressure hull. The unitary first half and the unitary second half are joined to form the composite pressure hull.

[0008] A further embodiment of the present disclosure provides a composite pressure hull. The composite pressure hull comprises a one-piece first half and a one-piece second half. The one-piece first half of the composite pressure hull comprises a dome portion and a cylindrical portion having a transition region comprising a joint formed during layup between the dome portion and the cylindrical portion. The one-piece second half of the composite pressure hull comprises a second dome portion and a second cylindrical portion having a second transition region comprising a second joint formed during layup between the second dome portion and the second cylindrical portion.

[0009] The features and functions may be realized alone in various embodiments of the present disclosure or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings.

[0010] The novel features believed characteristic of the illustrative embodiments are set forth in the appended claims, however, the illustrative embodiments, together with their preferred modes of use, further objects and features, will best be understood by reference to the following detailed description of the illustrative embodiments of the present disclosure when read in conjunction with the accompanying drawings. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram of a manufacturing environment in accordance with an illustrative embodiment. [Diagram 2] FIG. 1 illustrates an isometric view of a unitary first half of a composite pressure hull in accordance with an illustrative embodiment; [Diagram 3] FIG. 1 is an illustration of a set of composite plies against a mandrel in accordance with an illustrative embodiment; [Figure 4] FIG. 1 illustrates an isometric view of a composite pressure hull in accordance with an illustrative embodiment; [Diagram 5] 1 is a flowchart of a method of forming a composite pressure hull in accordance with an illustrative embodiment. [Figure 6] 1 is a flowchart of a method of forming a composite pressure hull in accordance with an illustrative embodiment. [Figure 7] FIG. 1 is an illustration of an aircraft manufacturing and service method in the form of a block diagram in accordance with an illustrative embodiment. [Figure 8] FIG. 1 is an illustration of an aircraft in the form of a block diagram in which an illustrative embodiment may be implemented; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Referring now to FIG. 1 , a block diagram of a manufacturing environment is depicted in accordance with an illustrative embodiment. A composite pressure hull 102 may be formed in the manufacturing environment 100. The composite pressure hull 102 comprises a one-piece first half 104 of the composite pressure hull 102 and a one-piece second half 106 of the composite pressure hull 102. The one-piece first half 104 comprises a dome portion 108 and a cylindrical portion 110 having a transition region 112 comprising a joint 114 formed during layup between the dome portion 108 and the cylindrical portion 110. The one-piece second half 106 of the composite pressure hull 102 comprises a second dome portion 116 and a second cylindrical portion 118 having a second transition region 120 comprising a second joint 122 formed during layup between the second dome portion 116 and the second cylindrical portion 118.

[0013] The dome portion 108 comprises a plurality of dome plies 126 laid up on a rounded end 140 of the mandrel 138. The dome plies 126 are laid up completely onto the rounded end 140 of the mandrel 138. The cylindrical portion 110 comprises cylindrical plies 124 laid up on a cylindrical surface 142. At least one of the cylindrical plies 124 extends onto the rounded end 140 of the mandrel 138. The portion of the cylindrical ply 124 that extends onto the rounded end 140 forms a transition region 112.

[0014] In some illustrative examples, the cylindrical plies of the plurality of cylindrical plies 124 are composite plies that generally begin at the cylindrical surface 142 and transition to a portion of the rounded end 140 of the mandrel 138. In some illustrative examples, many of the plurality of cylindrical plies 124 continue onto the rounded end 140 of the mandrel 138. In some illustrative examples, all of the plurality of cylindrical plies 124 continue onto the rounded end 140 of the mandrel 138. The material properties of the dome ply 126 may be undesirable at the edge of the rounded end 140 where the rounded end 140 meets the cylindrical surface 142. Thus, the dome ply 126 may be laid up on the rounded end 140 and terminate before intersecting with the cylindrical surface 142.

[0015] The transition region 112 comprises the cylindrical ply 124 of the cylindrical portion 110 and the dome ply 126 of the dome portion 108. In some illustrative examples, the transition region 112 is formed at a rounded end 140 of the mandrel 138.

[0016] In some illustrative examples, the joint 114 is formed within the transition region 112. In some illustrative examples, the joint 114 takes the form of at least one scarf joint. In some illustrative examples, the joint 114 takes the form of a staggered ply splice 132. In some illustrative examples, the joint 114 is formed by staggering lengths 127 of the dome plies 126. In some illustrative examples, the joint 114 is formed by staggering lengths 125 of the cylindrical plies 124. In some illustrative examples, the joint 114 comprises overlapping sets of dome plies 128 and sets of cylindrical plies 130. As used herein, an item "set" is one or more items. Thus, each set of the sets of dome plies 128 includes one or more dome plies. Each set of the sets of cylindrical plies 130 includes one or more cylindrical plies. In some illustrative examples, the joint 114 is formed by a series of adjacent sets of dome plies 128 and sets of cylindrical plies 130.

[0017] In some illustrative examples, the joint 114 comprises adjacent plies between the set of dome plies 128 and the set of cylindrical plies 130. In some illustrative examples, the joint 114 includes the set of dome plies 128 and the set of cylindrical plies 130 that are slightly gapped.

[0018] In some illustrative examples, transition region 112 has a series of joints between plies of the same thickness. In these illustrative examples, transition region 112 includes at least one additional joint in addition to joint 114. In some illustrative examples, transition region 112 comprises a set of joints, including joint 114, that are staggered through the thickness of unitary first half 104 and separated to minimize repetition anywhere within transition region 112.

[0019] In some illustrative examples, laying up the dome plies 126 and the cylindrical plies 124 includes alternating laying up of a set of dome plies 128 and a set of cylindrical plies 130 to form the joint 114. Each set of plies in both the set of dome plies 128 and the set of cylindrical plies 130 includes composite plies of any desired quantity, any desired fiber angle, and any desired size. The ply quantity, fiber angle, and ply size are based on the design of the unitary first half 104. Each set of plies has its own independent order of plies, ply quantity, fiber angle, and ply size.

[0020] In some illustrative examples, the set of plies includes two or more plies. In some illustrative examples, the set of plies includes two or more sizes of plies. In some illustrative examples, the set of plies includes two or more transition angles.

[0021] Each set of plies can have any desired characteristics, so that a subsequently laid set of plies can have at least one of a different quantity of plies, a different fiber angle, or a different size ply than a previously laid set of plies.

[0022] Thus, the layup of the dome ply 126 and the layup of the cylindrical ply 124 are performed in unison to form the transition region 112. In some illustrative examples, the dome plies of the dome ply 126 may be laid up simultaneously with the cylindrical plies of the cylindrical ply 124. In some illustrative examples, a single automated fiber layup head, such as the composite tow laying head 148, may be used to alternately lay up the dome plies 126 and the cylindrical plies 124.

[0023] The dome ply 126 and the cylindrical ply 124 are laid up on a mandrel 138 and cured. After curing, the one-piece first half 104 is a half capsule 136 that can be joined to the one-piece second half 106 to form the composite pressure hull 102. The half capsule 136 is formed without any openings or holes in the dome ply 126. In some illustrative examples, the half capsule 136 is formed without any openings or holes other than the openings in the half capsule 136 formed by the cylindrical ply 124.

[0024] Half capsule 136 comprises a body 135 and a cap 137 with a junction 139 between body 135 and cap 137. In some illustrative examples, junction 139 is where the curvature changes. In some illustrative examples, body 135 is formed entirely by cylindrical portion 110. In some illustrative examples, cap 137 includes transition region 112. In some illustrative examples, cap 137 comprises dome portion 108, transition region 112, and a portion of cylindrical portion 110.

[0025] The unitary first half 104 is formed from a composite material 134. The composite material 134 is laid up by a composite tow laying head 148 by laying down a plurality of tows 146.

[0026] The plurality of tows 146 are laid up on the rounded end 140 of the mandrel 138 to form the dome ply 126. The plurality of tows 146 are laid up on the cylindrical surface 142 to form the cylindrical ply 124. In some illustrative examples, at least one of the cylindrical plies 124 includes laying up the plurality of tows 146 on the cylindrical surface 142 and extending partially over the rounded end 140 of the mandrel 138.

[0027] The one-piece second half 106 includes a second cylindrical portion 118 and a second dome portion 116 with a second transition region 120 between the second cylindrical portion 118 and the second dome portion 116. The second transition region 120 includes a second cylindrical ply 150 of the second cylindrical portion 118 and a second dome ply 152 of the second dome portion 116. In some illustrative examples, the second transition region 120 includes a second joint 122.

[0028] In some illustrative examples, the second joint 122 takes the form of at least one scarf joint. In some illustrative examples, the second joint 122 takes the form of a staggered ply splice 154. In some illustrative examples, the second joint 122 is formed by staggering lengths of the second dome plies 152. In some illustrative examples, the second joint 122 is formed by staggering lengths of the second cylindrical plies 150. In some illustrative examples, the second joint 122 comprises overlapping sets of dome plies and sets of cylindrical plies. In some illustrative examples, the second joint 122 is formed by a series of adjacent sets of second dome plies and sets of second cylindrical plies.

[0029] In some illustrative examples, laying up the second dome ply 152 and the second cylindrical ply 150 includes alternating laying up sets of second dome plies and sets of second cylindrical plies to form the second joint 122. Each set of plies includes composite plies of any desired quantity, any desired fiber angle, and any desired size. The quantity of plies, fiber angle, and size of the plies are based on the design of the one-piece second half 106.

[0030] The layup of the second dome ply 152 and the layup of the second cylindrical ply 150 are performed in unison to form the second transition region 120. In some illustrative examples, the dome plies of the second dome ply 152 may be laid up simultaneously with the cylindrical plies of the second cylindrical ply 150. In some illustrative examples, a single automated fiber layup head, such as the composite tow laying head 148, may be used to alternately lay up the second dome ply 152 and the second cylindrical ply 150.

[0031] The second dome ply 152 and the second cylindrical ply 150 are laid up and cured on the same mandrel. In some illustrative examples, the one-piece second half 106 can be formed on the same mandrel as the one-piece first half 104, the mandrel 138. In some illustrative examples, the one-piece second half 106 can be formed on the rounded end 140 and cylindrical surface 142 of the mandrel 138 before or after forming the one-piece first half 104 on the mandrel 138. In some illustrative examples, the one-piece second half 106 is formed on a different mandrel than the one-piece first half 104. In some illustrative examples, the one-piece second half 106 is laid up and cured on the mandrel 160.

[0032] The second dome portion 116 is laid up on a rounded end of a mandrel, such as either mandrel 138 or mandrel 160. The second dome portion 116 is laid up entirely on the rounded end of the mandrel. The second cylindrical portion 118 is laid up on a cylindrical surface of a mandrel, such as either mandrel 138 or mandrel 160. At least one cylindrical ply of the second cylindrical portion 118 extends over the rounded end of the mandrel. The end of the second cylindrical portion 118 that extends over the rounded end forms a second transition region 120.

[0033] In some illustrative examples, the cylindrical plies of the second cylindrical portion 118 are generally composite plies that begin at a cylindrical surface, such as the cylindrical surface 142, and transition to a portion of a rounded end, such as the rounded end 140 of the mandrel 138. In some illustrative examples, much of the second cylindrical ply 150 of the second cylindrical portion 118 continues onto the rounded end 140 of the mandrel 138. In some illustrative examples, all of the second cylindrical ply 150 of the second cylindrical portion 118 continues onto the rounded end 140 of the mandrel 138. The material properties of the second dome ply 152 may be undesirable at the edge of the rounded end 140 where the rounded end 140 meets the cylindrical surface 142. Thus, the second dome ply 152 may be laid up on the rounded end 140 and terminate before intersecting with the cylindrical surface 142.

[0034] After curing, the one-piece second half 106 is a half capsule 156 that can be joined to the one-piece first half 104 to form the composite pressure hull 102. The half capsule 156 is formed without any openings or holes in the second dome ply 152. In some illustrative examples, the half capsule 156 is formed without any openings or holes other than the openings in the half capsule 156 formed by the second cylindrical ply 150.

[0035] Half capsule 156 comprises a body 155 and a cap 157 with a junction 159 between body 155 and cap 157. In some illustrative examples, junction 159 is where the curvature changes. In some illustrative examples, body 155 is formed entirely by second cylindrical portion 118. In some illustrative examples, cap 157 includes second transition region 120. In some illustrative examples, cap 157 comprises second dome portion 116, second transition region 120, and a portion of second cylindrical portion 118.

[0036] The one-piece second half 106 is formed from a composite material 158. In some illustrative examples, the composite material 158 is laid up by a composite tow laying head 148 by laying down a plurality of tows 146. In some other illustrative examples, the composite material 158 may be laid up by a different composite tow layup head than the laid up one-piece first half 104.

[0037] In some illustrative examples, the plurality of tows 146 are laid up on a rounded end 162 of a mandrel 160 to form a second dome ply 152. In some illustrative examples, the plurality of tows 146 are laid up on a cylindrical surface 164 to form a second cylindrical ply 150.

[0038] In some illustrative examples, the one-piece first half 104 has the same layup design as the one-piece second half 106. In some illustrative examples, the same method is performed to lay up the one-piece first half 104 and the one-piece second half 106.

[0039] Laying up the plies of the one-piece first half 104 or the one-piece second half 106 includes laying up a plurality of alternating paths 144, each path of the plurality of alternating paths 144 comprising a plurality of tows 146. For example, each dome ply of the dome portion 108 is laid up as a plurality of alternating paths, each path comprising a plurality of tows. Similarly, each cylindrical ply of the cylindrical portion 110 is laid up as a plurality of alternating paths, each path comprising a plurality of tows. In some illustrative examples, laying up the one-piece first half 104 of the composite pressure hull 102 includes laying up each cylindrical ply of the cylindrical portion 110 as a plurality of alternating paths 144, each path of the plurality of alternating paths 144 comprising a plurality of tows 146.

[0040] The composite pressure hull 102 is formed by a ring 166 joining the cylindrical portion 110 and the second cylindrical portion 118. In some illustrative examples, the ring 166 is bonded between the cylindrical portion 110 and the second cylindrical portion 118 to form the composite pressure hull 102. The ring 166 is provided in place to provide access between the composite pressure hull 102 and an environment external to the composite pressure hull 102. In some illustrative examples, the ring 166 includes a plurality of holes 172 to provide access to the interior of the composite pressure hull 102. In some illustrative examples, the ring 166 includes a metal 168. In some illustrative examples, the ring 166 includes a composite material 170.

[0041] The illustration of manufacturing environment 100 in FIG. 1 is not meant to imply physical or architectural limitations to the manner in which an illustrative embodiment may be implemented. Other components in addition to or in place of the illustrated components may be used. Some components may be unnecessary. Also, the blocks are presented to illustrate some functional components. One or more of these blocks may be combined, divided, or combined and divided into different blocks when implemented in an illustrative embodiment.

[0042] For example, each ply of the composite pressure hull 102 is laid up by a composite tow laying head, such as composite tow laying head 148. In some illustrative examples, two or more composite tow laying heads are used to lay up the one-piece first half 104 on the mandrel 138. In some illustrative examples, a different composite tow laying head is used to lay up the one-piece second half 106 than the one used to lay up the one-piece first half 104. Any desired number of composite tow laying heads may be used to lay up the one-piece first half 104 and the one-piece second half 106 on the mandrel 138 and / or mandrel 160.

[0043]

[0023] With reference now to Figure 2, an isometric view of a one-piece half of a composite pressure hull on a mandrel is depicted in accordance with an illustrative embodiment. One-piece half 200 is a physical implementation of one of one-piece first half 104 or one-piece second half 106 of Figure 1.

[0044] One-piece half 200 is one half of a composite pressure hull. One-piece half 200 comprises a dome portion 202 and a cylindrical portion 204. One-piece half 200 further comprises a transition region 205 comprising a joint 207 formed during layup between dome portion 202 and cylindrical portion 204.

[0045] The one-piece half 200 is laid up on a mandrel 206. The one-piece half 200 is formed by laying up dome plies 208 and cylindrical plies 210 on the mandrel 206. The dome plies 208 and cylindrical plies 210 are laid up in alternating order to form a transition region 205. The alternating manner of laying up can have any desired characteristics. A portion of the dome plies 208 is laid up before laying up a portion of the cylindrical plies 210. Any desired quantity and size of dome plies 208 can be laid up before laying up any desired quantity and size of cylindrical plies 210.

[0046] The layup of the one-piece half 200 can be described as an alternating layup of a set of dome plies, i.e., dome plies 208, and a set of cylindrical plies, i.e., cylindrical plies 210. Each set of plies, both the set of dome plies and the set of cylindrical plies, includes composite plies of any desired quantity, any desired fiber angle, and any desired size. The number of plies, fiber angle, and size of the plies are based on the design of the one-piece half 200. Each set of plies has its own independent order of plies, number of plies, fiber angle, and size of the plies.

[0047] In some illustrative examples, the set of plies includes two or more plies. In some illustrative examples, the set of plies includes two or more sizes of plies. In some illustrative examples, the set of plies includes two or more transition angles.

[0048] Each set of plies can have any desired characteristics, so that a subsequently laid set of plies can have at least one of a different quantity of plies, a different fiber angle, or a different size ply than a previously laid set of plies.

[0049] Thus, the layup of the dome ply 208 and the layup of the cylindrical ply 210 are performed in unison to form the transition region 205. In some illustrative examples, the dome ply of the dome ply 208 may be laid up simultaneously with the cylindrical ply of the cylindrical ply 210. In some illustrative examples, a single automated fiber layup head may be used to alternately lay up the dome ply 208 and the cylindrical ply 210.

[0050] The dome ply 208 and cylindrical ply 210 are laid up and cured on the mandrel 206. After curing, the integral half 200 is a half capsule that can be joined to an integral second half to form a composite pressure hull.

[0051] 2, the unitary half 200 has a dome portion 202 without any openings or holes. The dome portion 202 completely covers the rounded ends of each of the mandrels 206. The cylindrical portion 204 completely covers the cylindrical surfaces of each of the mandrels 206.

[0052] 3, a view of a composite ply set relative to a mandrel is depicted in accordance with an illustrative embodiment. In view 300, a cylindrical ply set 302 is depicted exploded onto a cylindrical surface 304 of a mandrel 306. In view 300, a dome ply set 308 is depicted exploded onto a rounded end 310 of the mandrel 306.

[0053] View 300 is provided solely for ease of explanation. Each ply is laid up not as a single sheet, but as multiple alternating passes, with each pass of the multiple alternating passes comprising multiple tows. Each ply is laid up by an automated fiber placement head that lays up the multiple alternating passes on a mandrel 306. View 300 is provided for illustration of the coordinated layup of dome and cylindrical plies to form dome and cylindrical portions of a one-piece half, such as the one-piece first half 104 or the one-piece second half 106 of FIG. 1. The set of cylindrical plies 302 and the set of dome plies 308 can be used to lay up the one-piece half 200 of FIG. 2.

[0054] Dome ply set 308 includes dome ply set 312, dome ply set 314, and dome ply set 316. Dome ply set 312 includes any desired quantity of plies, any desired fiber angle, and any desired size. Dome ply set 312 includes one or more plies. Dome ply set 312 includes one or more transition angles. Dome ply set 312 includes one or more ply sizes. Similarly, dome ply set 314 and dome ply set 316 include any desired quantity of plies, any desired fiber angle, and any desired size.

[0055] As depicted, dome ply set 312 is smaller than dome ply set 314. Dome ply set 314 covers a larger portion of rounded end 310 of mandrel 306 than dome ply set 312. The difference in size between dome ply set 312, dome ply set 314, and dome ply set 316 can be used to form a transition region between the dome and cylindrical portions of the one-piece halves of the composite pressure hull.

[0056] As depicted, each of the sets of dome plies 308 covers the center of a rounded end 310 of the mandrel 306. Thus, the resulting dome section of the composite pressure hull does not have a center hole at the apex of the dome section.

[0057] Each of the cylindrical ply sets 302 has a different length. For example, cylindrical ply set 318 is longer than cylindrical ply set 320. Cylindrical ply set 320 is longer than cylindrical ply set 322. Staggering the length of the cylindrical ply sets 302 can be done to form a transition area between the resulting dome portion and the resulting cylindrical portion. Staggering the length of the cylindrical ply sets 302 can be done to form a junction with the dome ply set 308.

[0058] The resulting cylindrical section comprises cylindrical ply sets 302. In some illustrative examples, at least one of cylindrical ply sets 302 extends over a junction 307 between cylindrical surface 304 and rounded end 310 and over rounded end 310 of mandrel 306. Junction 307 is where the curvature changes between cylindrical surface 304 and rounded end 310.

[0059] The set of cylindrical plies 302 and the set of dome plies 308 can be laid up in any desired order. In some illustrative examples, each of the sets of dome plies 308 is laid up before the respective set of cylindrical plies. In some other illustrative examples, two or more sets of plies from either the set of dome plies 308 or the set of cylindrical plies 302 are laid up before laying up plies from the other of the set of dome plies 308 or the set of cylindrical plies 302.

[0060] In one illustrative example, dome ply set 312 is laid up, followed by cylindrical ply set 318, dome ply set 314, cylindrical ply set 320, dome ply set 316, and cylindrical ply set 322. In another illustrative example, dome ply set 312 is laid up, followed by dome ply set 314, cylindrical ply set 318, cylindrical ply set 320, dome ply set 316, and cylindrical ply set 322. Any desired order of ply sets can be laid up based on the design of the integral halves. Any desired order of ply sets can be laid up based on the design of the transition regions within the integral halves.

[0061] Although view 300 is an exploded view, each ply in cylindrical ply set 302 is laid up as multiple alternating passes of multiple tows onto mandrel 306. Cylindrical ply set 302 is not pulled and is laid down as a ply. Similarly, although view 300 is an exploded view, each ply in dome ply set 308 is laid up as multiple alternating passes of multiple tows onto mandrel 306.

[0062] After curing, the unitary first half formed on the mandrel 306 has a semi-capsule shape that includes a cap over the rounded end 310 of the mandrel 306, a body over the cylindrical surface 304 of the mandrel 306, and a joint connecting the cap and body. The joint is located at the junction between the rounded end 310 and the cylindrical surface 304 of the mandrel 306.

[0063] The one-piece first half semi-capsule shaped cap comprises a set of dome plies 308. The one-piece first half semi-capsule shaped body comprises a set of cylindrical plies 302. The ends of the cylindrical plies extend over a rounded end 310 and form part of the cap in the one-piece first half. A transition area formed between the set of dome plies 308 and the set of cylindrical plies 302 is laid up at the rounded end 310 and resides within the cap.

[0064] Turning now to Figure 4, an isometric view of a composite pressure hull is depicted in accordance with an illustrative embodiment. Composite pressure hull 400 is a physical implementation of composite pressure hull 102 of Figure 1. One of integral first half 402 or integral second half 404 of composite pressure hull 400 may be the same as integral half 200 of Figure 2.

[0065] Composite pressure hull 400 comprises a one-piece first half 402 and a one-piece second half 404. One-piece first half 402 comprises a dome portion 406 and a cylindrical portion 408 with a transition region 410 comprising a joint formed during layup between dome portion 406 and cylindrical portion 408. Transition region 410 comprises the cylindrical ply of cylindrical portion 408 and the dome ply of dome portion 406.

[0066] The one-piece first half 402 takes the form of a half-capsule 403 comprising a body 405, a cap 407, and a junction 411 between the body 405 and the cap 407. The curvature of the half-capsule 403 changes at the junction 411 between the body 405 and the cap 407.

[0067] In some illustrative examples, body 405 is formed entirely from cylindrical portion 408. In some illustrative examples, cap 407 comprises a transition region 410. In some illustrative examples, cap 407 comprises dome portion 406, transition region 410, and an end of cylindrical portion 408.

[0068] The transition region 410 is located at any desired location within the one-piece first half 402 between the dome portion 406 and the cylindrical portion 408. The length of the dome portion 406 can be adjusted based on the design of the one-piece first half 402. The transition region 410 is located based on the length of the dome portion 406. In some illustrative examples, the transition region 410 is formed at each rounded end of the mandrel. In some illustrative examples, the transition region 410 is located between the boundary 420 and the boundary 422 in the one-piece first half 402.

[0069] The dome portion 406 of the composite pressure hull 400 does not have a center hole at the apex 409 of the dome portion 406. In some illustrative examples, for a localization system having an X-axis (0 degrees) extending parallel to the body 405 through the apex 409 and a Y-axis (90 degrees) extending through the joint 411, the transition region 410 can be located within a range of 45 degrees to 75 degrees.

[0070] The unitary second half 404 of the composite pressure hull 400 includes a second dome portion 412 and a second cylindrical portion 414 with a second transition region 416 comprising a second joint formed during layup between the second dome portion 412 and the second cylindrical portion 414. The second transition region 416 includes the cylindrical ply of the second cylindrical portion 414 and the dome ply of the second dome portion 412.

[0071] As depicted, one-piece first half 402 is a half-capsule. As depicted, one-piece second half 404 is a half-capsule. In some illustrative examples, one-piece first half 402 has the same layup design as one-piece second half 404.

[0072] The unitary second half 404 takes the form of a half-capsule 423 comprising a body 425, a cap 427, and a junction 429 between the body 425 and the cap 427. The curvature of the half-capsule 423 changes at the junction 429 between the body 425 and the cap 427.

[0073] In some illustrative examples, the body 425 is formed entirely from the second cylindrical portion 414. In some illustrative examples, the cap 427 comprises the second transition region 416. In some illustrative examples, the cap 407 includes the second dome portion 412, the second transition region 416, and an end of the second cylindrical portion 414.

[0074] The second transition region 416 is disposed at any desired location within the one-piece second half 404 between the second dome portion 412 and the second cylindrical portion 414. The length of the second dome portion 412 can be adjusted based on the design of the one-piece second half 404. The second transition region 416 is disposed based on the length of the second dome portion 412. In some illustrative examples, the second transition region 416 is formed at each rounded end of the mandrel. In some illustrative examples, the second transition region 416 is disposed between the boundary 424 and the boundary 426 in the one-piece second half 404.

[0075] The second dome portion 412 of the composite pressure hull 400 does not have a center hole at the apex of the second dome portion 412. In some illustrative examples, for a localization system having an X-axis (0 degrees) extending parallel to the body 425 through the apex and a Y-axis (90 degrees) extending through the joint 429, the second transition region 416 can be positioned within a range of 45 degrees to 75 degrees.

[0076] The composite pressure hull further comprises a ring 418 between the cylindrical portion 408 and the second cylindrical portion 414. The ring 418 is connected to the cylindrical portion 408 and the second cylindrical portion 414 in any desired manner. In some illustrative examples, the ring 418 is mechanically fixed to the cylindrical portion 408 and the second cylindrical portion 414. In some illustrative examples, the composite pressure hull further comprises a ring 418 bonded between the cylindrical portion 408 and the second cylindrical portion 414. In some illustrative examples, the ring 418 comprises a metal. In some illustrative examples, the ring 418 comprises a composite material. The ring 418 may be referred to as an interface ring. The ring 418 comprises several locations for receiving inputs and outputs from an environment external to the composite pressure hull 400.

[0077]

[0033] Turning now to Figure 5, a flowchart of a method for forming a composite pressure hull is depicted in accordance with an illustrative embodiment. Method 500 may be performed to form a composite pressure hull, such as composite pressure hull 102 of Figure 1. Method 500 may be performed to form integral half 200 of Figure 2. Method 500 may be performed using the integral half laid up and cured on mandrel 306 of Figure 3. Method 500 may be performed to form a composite pressure hull, such as composite pressure hull 400 of Figure 4.

[0078] The method 500 lays up a one-piece first half of the composite pressure hull (operation 502). The method 500 lays up a one-piece second half of the composite pressure hull (operation 504). The method 500 joins the one-piece first half to the one-piece second half to form the composite pressure hull (operation 506). Thereafter, the method 500 ends.

[0079] In some illustrative examples, laying up the one-piece first half of the composite pressure hull includes laying up a cylindrical portion and a dome portion on the mandrel to form a half capsule on the mandrel (operation 507). In some illustrative examples, laying up the cylindrical portion and the dome portion includes forming a transition region comprising a junction between the cylindrical portion and the dome portion (operation 508). In some illustrative examples, the dome portion is laid up on a rounded end of the mandrel. In some illustrative examples, the cylindrical portion is laid up on a cylindrical surface of the mandrel. In some illustrative examples, a portion of at least some of the cylindrical plies of the cylindrical portion extend over the rounded end of the mandrel. In some illustrative examples, the transition region is formed primarily at the rounded end of the mandrel. In some illustrative examples, the transition region is formed by the cylindrical plies extending over the rounded end of the mandrel.

[0080] The joint is formed simultaneously with the formation of the dome portion and the cylindrical portion. In these illustrative examples, the joint can take any desired form. In some illustrative examples, the joint between the dome portion and the cylindrical portion at the same level can be gapped, butted, overlapped, or something else. In some illustrative examples, the joint comprises two scarves staggered through the thickness of the one-piece first half.

[0081] In some illustrative examples, forming the transition region includes alternating layups of cylindrical plies and dome plies to form a joint (operation 510). The layups of the dome plies and the layups of the cylindrical plies are performed in unison to form the transition region.

[0082] In some illustrative examples, laying up the one-piece first half of the composite pressure hull includes laying up each cylindrical ply of the cylindrical portion as a plurality of alternating passes, each pass of the plurality of alternating passes comprising a plurality of tows (operation 512). In some illustrative examples, laying up the one-piece first half of the composite pressure hull includes laying up each dome ply of the dome portion as a plurality of alternating passes, each pass of the plurality of alternating passes comprising a plurality of tows. In some illustrative examples, laying up the cylindrical portion and the dome portion includes a single automated fiber layup head laying up alternating sets of dome plies and sets of cylindrical plies (operation 511).

[0083] In some illustrative examples, method 500 cures the one-piece first half before joining the one-piece first half to the one-piece second half (operation 513). In some illustrative examples, method 500 cures the one-piece second half before joining the one-piece first half to the one-piece second half.

[0084] In some illustrative examples, laying up the one-piece second half of the composite pressure hull includes laying up the second cylindrical portion and the second dome portion on the mandrel (operation 514). In some illustrative examples, laying up the second cylindrical portion and the second dome portion includes forming a transition region comprising a second joint between the second cylindrical portion and the second dome portion (operation 516). In some illustrative examples, laying up the one-piece second half of the composite pressure hull includes laying up each second cylindrical ply of the second cylindrical portion as a plurality of alternating passes, each pass of the plurality of alternating passes comprising a plurality of tows. In some illustrative examples, laying up the one-piece second half of the composite pressure hull includes laying up each second dome ply of the second dome portion as a plurality of alternating passes, each pass of the plurality of alternating passes comprising a plurality of tows.

[0085] In some illustrative examples, laying up the one-piece second half of the composite pressure hull is performed on the same mandrel as laying up the one-piece first half of the composite pressure hull (operation 518). In some illustrative examples, laying up the one-piece first half utilizes the same layup path as laying up the one-piece second half (operation 520).

[0086] In some illustrative examples, joining the one-piece first half to the one-piece second half includes bonding a ring to both the one-piece first half and the one-piece second half (Operation 522). In some illustrative examples, the ring may also be referred to as a weld ring. In some illustrative examples, the ring may also be referred to as an interface ring. In some illustrative examples, the ring comprises a metal. In some illustrative examples, the ring comprises a composite material.

[0087]

[0033] Referring now to Figure 6, a flowchart of a method for forming a composite pressure hull is depicted in accordance with an illustrative embodiment. Method 600 may be performed to form a composite pressure hull, such as composite pressure hull 102 of Figure 1. Method 600 may be performed to form one-piece half 200 of Figure 2. Method 600 may be performed using one-piece half laid up and cured on mandrel 306 of Figure 3. Method 600 may be performed to form a composite pressure hull, such as composite pressure hull 400 of Figure 4.

[0088] The method 600 lays up a dome ply and a cylindrical ply on a mandrel (operation 602) to form a unitary first half of the composite pressure hull. The method 600 lays up a second dome ply and a second cylindrical ply on the mandrel (operation 604) to form a unitary second half of the composite pressure hull. The method 600 joins the unitary first half and the unitary second half (operation 606) to form the composite pressure hull. The method 600 then ends.

[0089] In some illustrative examples, laying up the dome ply and the cylindrical ply is performed such that a joint is formed between the uncured composite material of the dome portion and the uncured composite material of the cylindrical portion (Operation 608). In these illustrative examples, the joint can take any desired form. In some illustrative examples, the joint between the dome portion and the cylindrical portion at the same level can be at least one of gapped, butted, overlapped, or something else. In some illustrative examples, the joint comprises two scarves staggered through a thickness of the integral first half. In some illustrative examples, laying up the dome ply and the cylindrical ply includes laying up the dome ply and the cylindrical ply by the same automated fiber placement head (Operation 609).

[0090] In some illustrative examples, laying up the dome plies and the cylindrical plies includes alternating laying up sets of dome plies and sets of cylindrical plies to form a joint (operation 610). By alternating laying up sets of dome plies and sets of cylindrical plies, a transition region is formed from the dome plies and the cylindrical plies.

[0091] In some illustrative examples, the method 600 includes curing the one-piece first half of the composite pressure hull on the mandrel prior to joining the one-piece first half to the one-piece second half (operation 612). In some illustrative examples, joining the one-piece first half to the one-piece second half includes bonding a ring to both the one-piece first half and the one-piece second half (operation 614).

[0092] As used herein, the phrase "at least one of," when used with a list of items, means that different combinations of one or more of the listed items may be used, and only one of each item in the list may be required. For example, "at least one of item A, item B, or item C" may include, without limitation, item A, item A and item B, or item B. This example may also include item A, item B, and item C, or item B and item C. Of course, any combination of these items may be present. In other examples, "at least one of" may be, for example, without limitation, two items A, one item B, and ten items C, or four items B and seven items C, or any other suitable combination. The items may be specific objects, things, or categories. In other words, "at least one of" means that any combination of items and number of items from the list may be used, but not all of the items in the list are required.

[0093] As used herein, "some," when used in reference to an item, means one or more items. As used herein, "set," when used in reference to an item, means one or more items. Thus, a set of plies includes one or more plies.

[0094] The flowcharts and block diagrams in the various depicted embodiments illustrate the architecture, functionality, and operation of some possible implementations of apparatuses and methods in the illustrative embodiments. In this regard, each block in the flowchart or block diagram may represent at least one of a module, a segment, a function, or a portion of an operation or step.

[0095] In some alternative implementations of the exemplary embodiments, one or more functions shown in the blocks may be performed out of the order shown in the figures. For example, in some cases, two blocks shown in succession may be performed substantially simultaneously, or the blocks may sometimes be performed in the reverse order, depending on the functionality involved. Also, other blocks may be added in addition to the blocks shown in the flowcharts or block diagrams. Some blocks may be optional. For example, operations 508-522 may be optional. As another example, operations 608-614 may be optional.

[0096] Illustrative examples provide methods and designs for composite pressure hulls. In some illustrative examples, the composite pressure hulls may be used in high pressure environments. In some illustrative examples, the composite pressure hulls may be used as submersibles. In some illustrative examples, the composite pressure hulls may be used to hold high pressure. In some illustrative examples, the composite pressure hulls may be used to hold cryogenic or other high pressure gas fuels. In some illustrative examples, the composite pressure hulls may be used in aircraft.

[0097] An example embodiment of the disclosure may be described in the context of aircraft manufacturing and service method 700 shown in Figure 7 and aircraft 800 shown in Figure 8. Turning initially to Figure 7, an illustration of an aircraft manufacturing and service method in block diagram form is depicted in accordance with an example embodiment. During prototyping, aircraft manufacturing and service method 700 may include specification and design 702 and material procurement 704 of aircraft 800 in Figure 8.

[0098] During production, component and subassembly manufacturing 706 and systems integration 708 of the aircraft 800 takes place. The aircraft 800 may then go through certification and delivery 710 for placement in service 712. While in service 712 by a customer, the aircraft 800 is scheduled for routine maintenance and service 714, which may include modification, reconfiguration, alterations, or other maintenance and service.

[0099] Each process of aircraft manufacturing and service method 700 may be performed or accomplished by a system integrator, a third party, and / or an operator. In these examples, the operator may be a customer. For purposes of this description, a system integrator may include, without limitation, any number of aircraft manufacturers and major system subcontractors, a third party may include, without limitation, any number of vendors, subcontractors, and suppliers, an operator may be an airline, a leasing company, the military, a service provider, etc.

[0100] Referring now to Figure 8, an illustration of an aircraft in block diagram form is depicted in which an illustrative embodiment may be implemented. In this example, aircraft 800 is produced by aircraft manufacturing and service method 700 in Figure 7 and may include an airframe 802 with a number of systems 804 and an interior 806. Example systems 804 include one or more of a propulsion system 808, an electrical system 810, a hydraulic system 812, and an environmental system 814. Any number of other systems may also be included.

[0101] Apparatus and methods embodied herein may be used during at least one stage of aircraft manufacturing and service method 700. One or more illustrative embodiments may be manufactured or used during at least one of component and subassembly manufacturing 706, system integration 708, in-service 712, or maintenance and service 714 of Figure 7. For example, fuel tanks or other pressure vessels of aircraft 800 may be manufactured in accordance with an illustrative example.

[0102] Conventional composite pressure hulls have holes at the apex of the dome for system integration, for fuel, etc. An illustrative example provides a continuous dome composite structure. The cylindrical section and the dome section are integrated via a joint, such as a scarf joint.

[0103] The illustrative examples provide a continuous closed dome composite structure with an integrated zone of cylindrical and dome fibers. Two composite halves are fabricated and then joined at the base of the cylinder with a ring joint. In some illustrative examples, the ring joint is metal. The illustrative examples provide integration of continuous dome and cylindrical composite components.

[0104] The description of the various exemplary embodiments is presented for illustration and explanation, and is not intended to be exhaustive or limited to the disclosed forms of the embodiments. Many modifications and variations will be apparent to those skilled in the art. Furthermore, the various exemplary embodiments may provide different features compared to other exemplary embodiments. The selected embodiment or embodiments have been selected and described to best explain the principles of the embodiments, practical applications, and to enable others skilled in the art to understand the disclosure of the various embodiments with various modifications suitable for the particular use envisaged. [Explanation of symbols]

[0105] 200 integrated half body 202 Dome part 204 Cylindrical part 205 Transition Zone 206 Mandrel 207 Joint 208 Dome Ply 210 Cylindrical ply 300 Views 302 Cylindrical ply set 304 Cylindrical Surface 306 Mandrel 307 Joint 308 Dome Ply Set 310 Rounded Ends 312 Dome Ply Set 314 Dome Ply Set 316 Dome Ply Set 318 Cylindrical ply set 320 Set of cylindrical plies 322 Set of cylindrical plies 400 Composite Pressure Hull 402 One-piece first half 403 Half Capsule 404 One-piece second half 405 Main Unit 406 Dome part 407 Cap 408 Cylindrical part 409 Vertex 410 Transition Zone 411 Joint 412 Second Dome Section 414 Second cylindrical part 416 Second Transition Zone 418 Ring 420 Boundary 422 Boundary 423 half capsule 424 Boundary 425 Body 426 Boundary 427 Cap 429 Joint

Claims

1. A method (500) of forming a composite pressure hull (102, 400), comprising the steps of: laying up (502) a unitary first half (104, 402) of the composite pressure hull (102, 400); laying up (504) a unitary second half (106, 404) of the composite pressure hull (102, 400); joining (506) the one-piece first half (104, 402) to the one-piece second half (106, 404) to form the composite pressure hull (102, 400); The method (500).

2. 2. The method (500) of claim 1, wherein joining the one-piece first half (104, 402) to the one-piece second half (106, 404) comprises adhering (522) a ring (166, 418) to both the one-piece first half (104, 402) and the one-piece second half (106, 404).

3. 2. The method (500) of claim 1, wherein laying up the integral first half (104, 402) of the composite pressure hull (102, 400) comprises laying up (507) a cylindrical portion (110, 204, 408) and a dome portion (108, 202, 408) on a mandrel (138, 206, 306) to form a half capsule (136) on the mandrel.

4. 4. The method (500) of claim 3, wherein laying up the cylindrical portion (110, 204, 408) and the dome portion (108, 202, 408) includes forming (508) a transition region (112, 205, 410) that comprises a junction (114) between the cylindrical portion (110, 204, 408) and the dome portion (108, 202, 408).

5. 5. The method (500) of claim 4, wherein forming the transition region (112, 205, 410) comprises laying up (510) alternating cylindrical plies (124, 210) and dome plies (126, 208) to form the joint (114).

6. Curing (513) the one-piece first half (104, 402) before joining the one-piece first half (104, 402) to the one-piece second half (106, 404). The method of claim 4, further comprising:

7. 4. The method (500) of claim 3, wherein laying up the one-piece first half (104, 402) of the composite pressure hull (102, 400) comprises laying up (512) each cylindrical ply of the cylindrical portion (110, 204, 408) as a plurality of alternating passes (144), each pass of the plurality of alternating passes (144) comprising a plurality of tows (146).

8. 4. The method of claim 3, wherein laying up the cylindrical portion (110, 204, 408) and the dome portion (108, 202, 408) includes a single automated fiber layup head (148) laying up alternating sets of dome plies (128, 308) and sets of cylindrical plies (130, 302).

9. 2. The method (500) of claim 1, wherein laying up the one-piece second half (106, 404) of the composite pressure hull (102, 400) comprises laying up (514) a second cylindrical portion (118, 414) and a second dome portion (116, 412) on a mandrel (138, 206, 306).

10. 10. The method (500) of claim 9, wherein laying up the second cylindrical portion (118, 414) and the second dome portion (116, 412) includes forming (516) a second transition region (120, 416) comprising a second junction (122) between the second cylindrical portion (118, 414) and the second dome portion (116, 412).

11. 2. The method (500) of claim 1, wherein the step of laying up the one-piece second half (106, 404) of the composite pressure hull (102, 400) is performed (518) on the same mandrel (138, 206, 306) as the step of laying up the one-piece first half (104, 402) of the composite pressure hull (102, 400).

12. The method (500) of claim 1, wherein laying up the one-piece first half (104, 402) utilizes a same layup path (520) as laying up the one-piece second half (106, 404).

13. A method (600) of forming a composite pressure hull (102, 400), comprising the steps of: laying up (602) a dome ply (126, 208) and a cylindrical ply (124, 210) on a mandrel (138, 206, 306) to form a unitary first half (104, 402) of the composite pressure hull (102, 400); laying up (604) a second dome ply (152) and a second cylindrical ply (150) on a mandrel (138, 206, 306) to form a unitary second half (106, 404) of said composite pressure hull (102, 400); joining (606) the one-piece first half (104, 402) and the one-piece second half (106, 404) to form the composite pressure hull (102, 400); The method (600).

14. 14. The method (600) of claim 13, wherein the step of laying up the dome ply (126, 208) and the cylindrical ply (124, 210) is performed (608) such that a joint (114) is formed between the uncured composite material (134) of the dome portion (108, 202, 408) and the uncured composite material (134) of the cylindrical portion (110, 204, 408).

15. 14. The method of claim 13, wherein laying up a dome ply (126, 208) and a cylindrical ply (124, 210) comprises laying up (609) the dome ply (126, 208) and the cylindrical ply (124, 210) with a same automated fiber placement head (148).

16. 15. The method (600) of claim 14, wherein laying up the dome plies (126, 208) and the cylindrical plies (124, 210) comprises laying up (610) alternating sets of dome plies (128, 308) and sets of cylindrical plies (130, 302) to form the joint (114).

17. curing (612) the one-piece first half (104, 402) of the composite pressure hull (102, 400) on the mandrel (138, 206, 306) prior to joining the one-piece first half (104, 402) to the one-piece second half (106, 404).

14. The method of claim 13, further comprising:

18. 14. The method (600) of claim 13, wherein joining the one-piece first half (104, 402) to the one-piece second half (106, 404) comprises adhering (614) a ring (166, 418) to both the one-piece first half (104, 402) and the one-piece second half (106, 404).

19. A composite pressure hull (102, 400), comprising: a one-piece first half (104, 402) of said composite pressure hull (102, 400) comprising a dome portion (108, 202, 408) and a cylindrical portion (110, 204, 408) having a transition region (112, 205, 410) with a joint (114) formed during lay-up between said dome portion (108, 202, 408) and said cylindrical portion (110, 204, 408); a one-piece second half (106, 404) of said composite pressure hull (102, 400) comprising a second dome portion (116, 412) and a second cylindrical portion (118, 414) having a second transition region (120, 416) with a second joint (122) formed during lay-up between said second dome portion (116, 412) and said second cylindrical portion (118, 414); A composite pressure hull (102, 400).

20. 20. The composite pressure hull (102, 400) of claim 19, wherein the transition region (112, 205, 410) comprises a cylindrical ply (124, 210) of the cylindrical portion (110, 204, 408) and a dome ply (126, 208) of the dome portion (108, 202, 408).

21. a ring (166, 418) bonded between said cylindrical portion (110, 204, 408) and said second cylindrical portion (118, 414); 20. The composite pressure hull (102, 400) of claim 19, further comprising:

22. The composite pressure hull (102, 400) of claim 21, wherein the ring (166, 418) comprises a metal (168).

23. 20. The composite pressure hull (102, 400) of claim 19, wherein the one-piece first half (104, 402) has the same layup design as the one-piece second half (106, 404).

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