Composite pressure shell and method of forming

Abstract

The invention relates to a composite pressure shell and a method of forming. A monolithic first half of the composite pressure shell is laid. And laying the integral second half part of the composite pressure shell. The unitary first half is joined to the unitary second half to form a composite pressure shell.

Description

Technical Field

[0001] The present disclosure relates generally to composite material manufacturing, and more particularly to manufacturing composite pressure hulls. Background Art

[0002] Reducing weight is a problem in storing, manufacturing or transporting different 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. In order to reduce the weight of components such as pressure tanks, it may be desirable to manufacture the components from composite materials.

[0003] Composite materials are strong, lightweight materials produced by combining two or more functional components. For example, a composite material may include reinforcing fibers incorporated into a polymer resin matrix. The fibers may take the form of unidirectional tapes, woven fabrics or fabrics, or braids. The mechanical properties and other material properties of the composite material may be desirable for some embodiments. For example, the buoyancy of the composite material may be more ideal for diving applications.

[0004] It would therefore be desirable to have methods and apparatus that take into account at least some of the issues discussed above, as well as other possible issues. Summary of the invention

[0005] Embodiments of the present disclosure provide a method of forming a composite pressure hull. An integral first half of the composite pressure hull is laid up. An integral second half of the composite pressure hull is laid up. The integral first half is joined to the integral second half to form the composite pressure hull.

[0006] Another embodiment of the present disclosure provides a method of forming a composite pressure hull. A dome-shaped layer and a cylindrical layer are laid on a mandrel to form a monolithic first half of the composite pressure hull. A second dome-shaped layer and a second cylindrical layer are laid on the mandrel to form a monolithic second half of the composite pressure hull. The monolithic first half and the monolithic second half are joined to form the composite pressure hull.

[0007] Another embodiment of the present disclosure provides a composite pressure hull. The composite pressure hull includes an integral first half and an integral second half. The integral first half of the composite pressure hull includes a dome portion and a cylindrical portion, with a transition region between the dome portion and the cylindrical portion, and the transition region includes a joint formed during layup. The integral second half of the composite pressure hull includes a second dome portion and a second cylindrical portion, with a second transition region between the second dome portion and the second cylindrical portion, and the second transition region includes a second joint formed during layup.

[0008] The features and functions can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments, in which further details can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The novel features which are believed to be characteristic of the illustrative embodiments are set forth in the appended claims. However, the illustrative embodiments and their preferred modes of use, further objects and features will be best understood by reference to the following detailed description of illustrative embodiments of the present disclosure when read in conjunction with the accompanying drawings, in which:

[0010] Figure 1 is an illustration of a block diagram of a manufacturing environment according to an illustrative embodiment;

[0011] Figure 2 is an illustration of an isometric view of a unitary first half of a composite pressure hull according to an illustrative embodiment;

[0012] Figure 3 is an illustration of multiple sets of composite plies relative to a mandrel according to an illustrative embodiment;

[0013] Figure 4 is an illustration of an isometric view of a composite pressure hull according to an illustrative embodiment;

[0014] Figure 5 is a flow chart of a method of forming a composite pressure hull according to an illustrative embodiment;

[0015] Figure 6 is a flow chart of a method of forming a composite pressure hull according to an illustrative embodiment;

[0016] Figure 7 is an illustration of an aircraft manufacturing and service methodology in block diagram form in accordance with an illustrative embodiment; and

[0017] Figure 8 is an illustration of an aircraft in block diagram form in which illustrative embodiments may be implemented. DETAILED DESCRIPTION

[0018] Now turn to Figure 1, an illustration of 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 includes an integral first half 104 of the composite pressure hull 102 and an integral second half 106 of the composite pressure hull 102. The integral first half 104 includes a dome portion 108 and a cylindrical portion 110 with a transition region 112 between the dome portion 108 and the cylindrical portion 110, the transition region 112 including a joint 114 formed during layup. The integral second half 106 of the composite pressure hull 102 includes a second dome portion 116 and a second cylindrical portion 118 with a second transition region 120 between the second dome portion 116 and the second cylindrical portion 118, the second transition region 120 including a second joint 122 formed during layup.

[0019] The dome portion 108 includes a dome top sheet 126 laid up on a circular end 140 of a mandrel 138. The dome top sheet 126 is laid up completely on the circular end 140 of the mandrel 138. The cylindrical portion 110 includes a cylindrical ply 124 laid up on a cylindrical surface 142. At least one of the cylindrical plies 124 extends onto the circular end 140 of the mandrel 138. The portion of the cylindrical ply 124 that extends onto the circular end 140 forms a transition region 112.

[0020] In some illustrative examples, cylindrical plies of cylindrical plies 124 are composite plies that generally begin on cylindrical surface 142 and transition to a portion of circular end 140 of mandrel 138. In some illustrative examples, many of cylindrical plies 124 will continue onto circular end 140 of mandrel 138. In some illustrative examples, all of cylindrical plies 124 will continue onto circular end 140 of mandrel 138. The material properties of dome top sheet 126 may be undesirable at the edge of circular end 140, where circular end 140 intersects cylindrical surface 142. Therefore, dome top sheet 126 may be laid up on circular end 140 and terminate prior to intersecting cylindrical surface 142.

[0021] Transition region 112 includes cylindrical plies 124 of cylindrical portion 110 and dome plies 126 of dome portion 108 . In some illustrative examples, transition region 112 is formed on circular end 140 of mandrel 138 .

[0022] In some illustrative examples, joint 114 is formed in transition region 112. In some illustrative examples, joint 114 takes the form of at least one caulking joint. In some illustrative examples, joint 114 takes the form of staggered ply splices 132. In some illustrative examples, joint 114 is formed by staggered lengths 127 of dome top sheets 126. In some illustrative examples, joint 114 is formed by staggered lengths 125 of cylindrical plies 124. In some illustrative examples, joint 114 includes overlapping multiple groups of dome top sheets 128 and multiple groups of cylindrical plies 130. As used herein, a "group" of items is one or more items. Therefore, each group of dome top sheets in multiple groups of dome top sheets 128 includes one or more dome top sheets. Each group of cylindrical plies in multiple groups of cylindrical plies 130 includes one or more cylindrical plies. In some illustrative examples, joint 114 is formed by a series of adjacent multiple groups of dome top sheets 128 and multiple groups of cylindrical plies 130.

[0023] In some illustrative examples, joint 114 includes adjacent plies between groups of domed top sheets 128 and groups of cylindrical plies 130. In some illustrative examples, joint 114 includes groups of domed top sheets 128 and groups of cylindrical plies 130 with a slight gap.

[0024] 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 also includes at least one additional joint in addition to joint 114. In some illustrative examples, transition region 112 includes a set of joints, including joint 114, that are staggered through the thickness of unitary first half 104 and are separated to minimize duplication at any location within transition region 112.

[0025] In some illustrative examples, laying dome plies 126 and cylindrical plies 124 includes: alternately laying multiple sets of dome plies 128 and multiple sets of cylindrical plies 130 to form joint 114. Each set of plies for both multiple sets of dome plies 128 and multiple sets of cylindrical plies 130 includes any desired number, any desired fiber angle, and any desired size of composite plies. The number of plies, fiber angle, and size of plies are based on the design of monolithic first half 104. Each set of plies has its own independent ply sequence, number of plies, fiber angle, and ply size.

[0026] In some illustrative examples, a set of plies includes more than one ply. In some illustrative examples, a set of plies includes more than one size of ply. In some illustrative examples, a set of plies includes more than one fiber angle.

[0027] Since each set of plies may have any desired properties, a subsequently laid-up set of plies may have at least one of a different number of plies, a different fiber angle, or a different size of plies than a previously laid-up set of plies.

[0028] Thus, laying up dome top sheet 126 and laying up cylindrical plies 124 are performed in coordination to form transition region 112. In some illustrative examples, dome top sheets of dome top sheet 126 may be laid up simultaneously with cylindrical plies of cylindrical plies 124. In some illustrative examples, a single automated fiber placement head, such as composite tow placement head 148, may be used to alternately lay up dome top sheet 126 and cylindrical plies 124.

[0029] Dome top sheet 126 and cylindrical plies 124 are laid up and cured on mandrel 138. After curing, monolithic first half 104 is half-nacelle 136, which may be joined to monolithic second half 106 to form composite pressure hull 102. Half-nacelle 136 is formed without any openings or holes in dome top sheet 126. In some illustrative examples, half-nacelle 136 is formed without any openings or holes other than the openings of half-nacelle 136 formed by cylindrical plies 124.

[0030] Half-chassis 136 includes body 135 and cap 137 with a joint 139 between body 135 and cap 137. In some illustrative examples, joint 139 is the location of the change in curvature. In some illustrative examples, body 135 is formed entirely of cylindrical portion 110. In some illustrative examples, cap 137 includes transition region 112. In some illustrative examples, cap 137 includes dome portion 108, transition region 112, and a portion of cylindrical portion 110.

[0031] The unitary first half 104 is formed from a composite material 134. The composite material 134 is laid up by a composite tow placement head 148 by laying down a plurality of tows 146.

[0032] A plurality of tows 146 are laid up on circular end 140 of mandrel 138 to form domed ply 126. A plurality of tows 146 are laid up on cylindrical surface 142 to form cylindrical plies 124. In some illustrative examples, at least one cylindrical ply of cylindrical plies 124 includes a plurality of tows 146 laid up on cylindrical surface 142 and extending partially onto circular end 140 of mandrel 138.

[0033] Unitary second half 106 includes second cylindrical portion 118 and second dome portion 116, with second transition region 120 between second cylindrical portion 118 and second dome portion 116. Second transition region 120 includes second cylindrical ply 150 of second cylindrical portion 118 and second dome ply 152 of second dome portion 116. In some illustrative examples, second transition region 120 includes second joint 122.

[0034] In some illustrative examples, second joint 122 takes the form of at least one scarf joint. In some illustrative examples, second joint 122 takes the form of staggered ply splice 154. In some illustrative examples, second joint 122 is formed by staggered lengths of second dome plies 152. In some illustrative examples, second joint 122 is formed by staggered lengths of second cylindrical plies 150. In some illustrative examples, second joint 122 includes overlapping sets of dome plies and sets of cylindrical plies. In some illustrative examples, second joint 122 is formed by a series of adjacent sets of second dome plies and sets of second cylindrical plies.

[0035] In some illustrative examples, laying up second dome-shaped plies 152 and second cylindrical plies 150 includes alternately laying up multiple sets of second dome-shaped plies and multiple sets of second cylindrical plies to form second joint 122. Each set of plies includes any desired amount, any desired fiber angle, and any desired size of composite plies. The number of plies, fiber angle, and size of plies are based on the design of monolithic second half 106.

[0036] Laying up second dome top sheet 152 and laying up second cylindrical plies 150 are performed in coordination to form second transition region 120. In some illustrative examples, the dome top sheets of second dome top sheet 152 may be laid up simultaneously with the cylindrical plies of second cylindrical plies 150. In some illustrative examples, a single automated fiber placement head, such as composite tow placement head 148, may be used to alternately lay up second dome top sheet 152 and second cylindrical plies 150.

[0037] Second dome-shaped ply 152 and second cylindrical ply 150 are laid up and cured on the same mandrel. In some illustrative examples, integral second half 106 can be formed on the same mandrel as integral first half 104 and mandrel 138. In some illustrative examples, integral second half 106 can be formed on circular end 140 and cylindrical surface 142 of mandrel 138 before or after integral first half 104 is formed on mandrel 138. In some illustrative examples, integral second half 106 is formed on a different mandrel than integral first half 104. In some illustrative examples, integral second half 106 is laid up and cured on mandrel 160.

[0038] The second dome portion 116 is laid up on the circular end of a mandrel, such as mandrel 138 or mandrel 160. The second dome portion 116 is laid up completely on the circular end of the mandrel. The second cylindrical portion 118 is laid up on the cylindrical surface of a mandrel, such as mandrel 138 or mandrel 160. At least one cylindrical ply of the second cylindrical portion 118 extends onto the circular end of the mandrel. The end of the second cylindrical portion 118 extending onto the circular end forms a second transition region 120.

[0039] In some illustrative examples, the cylindrical plies of second cylindrical portion 118 are composite plies that generally begin on a cylindrical surface, such as cylindrical surface 142, and transition to a portion of a circular end, such as circular end 140 of mandrel 138. In some illustrative examples, many of second cylindrical plies 150 of second cylindrical portion 118 will continue onto circular end 140 of mandrel 138. In some illustrative examples, all of second cylindrical plies 150 of second cylindrical portion 118 will continue onto circular end 140 of mandrel 138. The material properties of second dome plies 152 may be undesirable at the edge of circular end 140, where circular end 140 intersects cylindrical surface 142. Therefore, second dome plies 152 may be laid up on circular end 140 and terminate before intersecting cylindrical surface 142.

[0040] After curing, integral second half 106 is half-tank 156, which may be joined to integral first half 104 to form composite pressure hull 102. Half-tank 156 is formed without any openings or holes in second dome-shaped ply 152. In some illustrative examples, half-tank 156 is formed without any openings or holes other than the openings of half-tank 156 formed by second cylindrical ply 150.

[0041] Half-chassis 156 includes body 155 and cap 157 with a joint 159 between body 155 and cap 157. In some illustrative examples, joint 159 is the location of the change in curvature. In some illustrative examples, body 155 is formed entirely of second cylindrical portion 118. In some illustrative examples, cap 157 includes second transition region 120. In some illustrative examples, cap 157 includes second dome portion 116, second transition region 120, and a portion of second cylindrical portion 118.

[0042] Unitary second half 106 is formed from composite material 158. In some illustrative examples, composite material 158 is laid up by composite tow placement head 148 by laying up plurality of tows 146. In some other illustrative examples, composite material 158 may be laid up by a different composite tow placement head than that used to lay up unitary first half 104.

[0043] In some illustrative examples, plurality of tows 146 are laid up on circular end 162 of mandrel 160 to form second dome-shaped ply 152. In some illustrative examples, plurality of tows 146 are laid up on cylindrical surface 164 to form second cylindrical ply 150.

[0044] In some illustrative examples, integral first half 104 has the same layup design as integral second half 106. In some illustrative examples, the same method is performed to layup integral first half 104 and integral second half 106.

[0045] Laying down the plies of the integral first half 104 or the integral second half 106 includes laying down a plurality of alternating paths 144, wherein each path in the plurality of alternating paths 144 includes a plurality of tows 146. For example, each dome ply of the dome portion 108 will be laid down as a plurality of alternating paths, wherein each path includes a plurality of tows. Similarly, each cylindrical ply of the cylindrical portion 110 will be laid down as a plurality of alternating paths, wherein each path includes a plurality of tows. In some illustrative examples, laying down the integral first half 104 of the composite pressure hull 102 includes laying down each cylindrical ply of the cylindrical portion 110 as a plurality of alternating paths 144, wherein each path in the plurality of alternating paths 144 includes a plurality of tows 146.

[0046] Composite pressure hull 102 is formed by joining ring 166 of cylindrical portion 110 and second cylindrical portion 118. In some illustrative examples, to form composite pressure hull 102, ring 166 is adhered between cylindrical portion 110 and second cylindrical portion 118. Ring 166 is provided for an approach location between composite pressure hull 102 and an environment external to composite pressure hull 102. In some illustrative examples, ring 166 includes a plurality of holes 172 to access the interior of composite pressure hull 102. In some illustrative examples, ring 166 includes metal 168. In some illustrative examples, ring 166 includes composite material 170.

[0047] Figure 1 The illustration of manufacturing environment 100 in FIG. 1 is not meant to imply physical or architectural limitations on the manner in which the illustrative embodiments may be implemented. Other components may be used in addition to or in place of the components shown. Some components may be unnecessary. Moreover, the blocks are presented to illustrate some functional components. When implemented in the illustrative embodiments, one or more of these blocks may be combined, divided, or combined and divided into different blocks.

[0048] For example, each ply of composite pressure shell 102 is laid up by a composite tow placement head, such as composite tow placement head 148. In some illustrative examples, more than one composite tow placement head is used to lay up integral first half 104 on mandrel 138. In some illustrative examples, a different composite tow placement head is used to lay up integral second half 106 than is used to lay up integral first half 104. Any desired number of composite tow placement heads may be used to lay up integral first half 104 and integral second half 106 on mandrel 138 and / or mandrel 160.

[0049] Now turn to Figure 2 , depicts an isometric view of a monolithic half of a composite pressure shell on a mandrel, according to an illustrative embodiment. The monolithic half 200 is Figure 1 The physical implementation of one of the integral first half 104 or the integral second half 106.

[0050] The monolithic half 200 is a half of a composite pressure hull. The monolithic half 200 includes a domed portion 202 and a cylindrical portion 204. The monolithic half 200 also includes a transition region 205 between the domed portion 202 and the cylindrical portion 204, the transition region 205 including a joint 207 formed during layup.

[0051] The monolithic half 200 has been laid up on a mandrel 206. The monolithic half 200 is formed by laying up a dome top sheet 208 and a cylindrical ply 210 on the mandrel 206. The dome top sheet 208 and the cylindrical ply 210 are laid up in an alternating manner to form the transition region 205. The alternating manner of laying up can have any desired characteristics. Portions of the dome top sheet 208 are laid up before portions of the cylindrical ply 210 are laid up. Any desired number and size of dome top sheets 208 can be laid up before any desired number and size of cylindrical plies 210 are laid up.

[0052] The layup of the monolithic half 200 can be described as alternating the layup of multiple sets of dome plies in the dome plies 208 and multiple sets of cylindrical plies of the cylindrical plies 210. Each set of plies for both the multiple sets of dome plies and the multiple sets of cylindrical plies includes any desired number, any desired fiber angle, and any desired composite ply size. The number of plies, fiber angle, and ply size are based on the design of the monolithic half 200. Each set of plies has its own independent ply sequence, number of plies, fiber angle, and ply size.

[0053] In some illustrative examples, a set of plies includes more than one ply. In some illustrative examples, a set of plies includes more than one size of ply. In some illustrative examples, a set of plies includes more than one fiber angle.

[0054] Since each set of plies may have any desired properties, a subsequently laid-up set of plies may have at least one of a different number of plies, a different fiber angle, or a different size of plies than a previously laid-up set of plies.

[0055] Thus, laying up dome top sheet 208 and laying up cylindrical plies 210 are performed in coordination to form transition region 205. In some illustrative examples, dome top sheets of dome top sheet 208 may be laid up simultaneously with cylindrical plies of cylindrical plies 210. In some illustrative examples, a single automated fiber placement head may be used to alternately lay up dome top sheet 208 and cylindrical plies 210.

[0056] Dome plies 208 and cylindrical plies 210 are laid up and cured on mandrel 206. After curing, monolithic half 200 is a half-shell that can be joined to a monolithic second half to form a composite pressure hull.

[0057] like Figure 2 As shown, the integral half 200 has a domed portion 202 without any openings or holes. The domed portion 202 completely covers a corresponding circular end of a mandrel 206. The cylindrical portion 204 completely covers a corresponding cylindrical surface of the mandrel 206.

[0058] Now turn to Figure 3 , depicts an illustration of multiple groups of composite plies relative to a mandrel according to an illustrative embodiment. In view 300, multiple groups of cylindrical plies 302 are depicted exploded on a cylindrical surface 304 of a mandrel 306. In view 300, multiple groups of circular plies 308 are depicted exploded on a circular end 310 of the mandrel 306.

[0059] View 300 is provided for ease of explanation only. Each ply will not be laid as a single sheet but as multiple alternating paths, wherein each of the multiple alternating paths includes multiple tows. Each ply is laid by an automated fiber placement head that lays the multiple alternating paths onto mandrel 306. View 300 is provided to explain the coordinated laying of dome-shaped and cylindrical plies to form a monolithic half (such as Figure 1 The dome portion and the cylindrical portion of the integral first half 104 or the integral second half 106 of the embodiment of the present invention. The plurality of groups of cylindrical layers 302 and the plurality of groups of dome layers 308 can be used for laying Figure 2 The integral half 200.

[0060] Groups of dome top sheets 308 include a group of dome top sheets 312, a group of dome top sheets 314, and a group of dome top sheets 316. Group of dome top sheets 312 includes any desired number of plies, any desired fiber angle plies, and any desired size plies. Group of dome top sheets 312 includes one or more plies. Group of dome top sheets 312 includes one or more fiber angles. Group of dome top sheets 312 includes one or more ply sizes. Likewise, group of dome top sheets 314 and group of dome top sheets 316 include any desired number of plies, any desired fiber angle plies, and any desired size plies.

[0061] As shown, set of dome top sheets 312 is smaller than set of dome top sheets 314. Set of dome top sheets 314 covers more of the circular end 310 of mandrel 306 than set of dome top sheets 312. The size difference between set of dome top sheets 312, set of dome top sheets 314, and set of dome top sheets 316 may be used to form a transition region between the domed portion and the cylindrical portion of the integral half of the composite pressure hull.

[0062] As shown, each set of dome top sheets in the plurality of sets of dome top sheets 308 will cover the center of the circular end 310 of the mandrel 306. Thus, the resulting dome portion of the composite pressure hull will not have a central hole at the apex of the dome portion.

[0063] Each set of cylindrical plies in the plurality of sets of cylindrical plies 302 has a different length. For example, a set of cylindrical plies 318 is larger than a set of cylindrical plies 320. A set of cylindrical plies 320 is longer than a set of cylindrical plies 322. The staggered lengths of the plurality of sets of cylindrical plies 302 can be performed to form a transition region between the resulting dome portion and the resulting cylindrical portion. The staggered lengths of the plurality of sets of cylindrical plies 302 can be performed to form a joint with the plurality of sets of dome plies 308.

[0064] The resulting cylindrical portion includes groups of cylindrical plies 302. In some illustrative examples, at least one group of cylindrical plies in groups of cylindrical plies 302 extends over a junction 307 between cylindrical surface 304 and circular end 310 and onto circular end 310 of mandrel 306. Junction 307 is a location where the curvature changes between cylindrical surface 304 and circular end 310.

[0065] Groups of cylindrical plies 302 and groups of dome plies 308 may be laid down in any desired order. In some illustrative examples, each group of dome plies in groups of dome plies 308 is laid down before a corresponding group of cylindrical plies. In some other illustrative examples, more than one group of plies from either group of dome plies 308 or group of cylindrical plies 302 is laid down before plies from other groups in group of dome plies 308 or group of cylindrical plies 302 are laid down.

[0066] In one illustrative example, a set of dome top sheets 312 is laid, followed by a set of cylindrical plies 318, a set of dome top sheets 314, a set of cylindrical plies 320, a set of dome top sheets 316, and a set of cylindrical plies 322. In another illustrative example, a set of dome top sheets 312 is laid, followed by a set of dome top sheets 314, a set of cylindrical plies 318, a set of cylindrical plies 320, a set of dome top sheets 316, and a set of cylindrical plies 322. Multiple sets of plies may be laid in any desired order based on the design of the monolithic halves. Multiple sets of plies may be laid in any desired order based on the design of the transition areas within the monolithic halves.

[0067] Although view 300 is an exploded view, each ply in the plurality of groups of cylindrical plies 302 is laid onto mandrel 306 as a plurality of alternating paths of a plurality of tows. A group of cylindrical plies 302 is not picked up and placed as a ply. Likewise, although view 300 is an exploded view, each ply in the plurality of groups of dome plies 308 is laid onto mandrel 306 as a plurality of alternating paths of a plurality of tows.

[0068] After curing, the integral first half formed on the mandrel 306 will have a half-chassis shape. The half-chassis shape will include a cap over the circular end 310 of the mandrel 306, a body over the cylindrical surface 304 of the mandrel 306, and a joint connecting the cap and the body. The joint will be located at the connection between the circular end 310 and the cylindrical surface 304 of the mandrel 306.

[0069] The half-tank shaped cover of the monolithic first half will include groups of dome-shaped top sheets 308. The half-tank shaped body of the monolithic first half will include groups of cylindrical plies 302. The ends of the cylindrical plies will extend onto the circular end 310 and will form part of the cover in the monolithic first half. The transition area formed between the groups of dome-shaped top sheets 308 and the groups of cylindrical plies 302 will be laid onto the circular end 310 and will be present in the top cover.

[0070] Now turn to Figure 4 , depicts an isometric view of a composite pressure hull according to an illustrative embodiment. The composite pressure hull 400 is Figure 1 The composite pressure hull 102 of FIG. 1 is a physical embodiment of the composite pressure hull 102. One of the integral first half 402 or the integral second half 404 of the composite pressure hull 400 may be connected to Figure 2 The integral half 200 is the same.

[0071] Composite pressure hull 400 includes an integral first half 402 and an integral second half 404. Integral first half 402 includes a dome portion 406 and a cylindrical portion 408 with a transition region 410 between dome portion 406 and cylindrical portion 408, transition region 410 including a joint formed during layup. Transition region 410 includes cylindrical plies of cylindrical portion 408 and dome plies of dome portion 406.

[0072] The unitary first half 402 takes the form of a half-chassis 403, which includes a body 405, a cap 407, and a joint 411 between the body 405 and the cap 407. The curvature of the half-chassis 403 changes at the joint 411 between the body 405 and the cap 407.

[0073] In some illustrative examples, body 405 is formed entirely of cylindrical portion 408. In some illustrative examples, cap 407 includes transition region 410. In some illustrative examples, cap 407 includes dome portion 406, transition region 410, and an end of cylindrical portion 408.

[0074] Transition region 410 is positioned at any desired location in unitary first half 402 between dome portion 406 and cylindrical portion 408. The length of dome portion 406 may be adjusted based on the design of unitary first half 402. Transition region 410 is positioned based on the length of dome portion 406. In some illustrative examples, transition region 410 is formed on a corresponding circular end of the mandrel. In some illustrative examples, transition region 410 is located between boundary 420 and boundary 422 in unitary first half 402.

[0075] Dome portion 406 of composite pressure hull 400 does not have a central hole at apex 409 of dome portion 406. In some illustrative examples, for a positioning system where the X-axis (0 degrees) extends through apex 409 and is parallel to body 405 and the Y-axis (90 degrees) extends through joint 411, transition region 410 may be positioned within a range of 45 degrees to 75 degrees.

[0076] The integral 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 between the second dome portion 412 and the second cylindrical portion 414, the second transition region 416 including a second joint formed during layup. The second transition region 416 includes cylindrical plies of the second cylindrical portion 414 and dome plies of the second dome portion 412.

[0077] As shown, integral first half 402 is a half-tank. As shown, integral second half 404 is a half-tank. In some illustrative examples, integral first half 402 has the same layup design as integral second half 404.

[0078] The unitary second half 404 takes the form of a half-chassis 423, which includes a body 425, a cap 427, and a joint 429 between the body 425 and the cap 427. The curvature of the half-chassis 423 changes at the joint 429 between the body 425 and the cap 427.

[0079] In some illustrative examples, body 425 is formed entirely of second cylindrical portion 414. In some illustrative examples, cap 427 includes second transition region 416. In some illustrative examples, cap 407 includes second dome portion 412, second transition region 416, and an end of second cylindrical portion 414.

[0080] Second transition region 416 is positioned at any desired location in unitary second half 404 between second dome portion 412 and second cylindrical portion 414. The length of second cylindrical portion 414 can be adjusted based on the design of unitary second half 404. Second transition region 416 is positioned based on the length of second dome portion 412. In some illustrative examples, second transition region 416 is formed on the corresponding circular end of the mandrel. In some illustrative examples, second transition region 416 is located between boundary 424 and boundary 426 in unitary second half 404.

[0081] Second dome portion 412 of composite pressure hull 400 does not have a central hole at the apex of second dome portion 412. In some illustrative examples, for a positioning system where the X-axis (0 degrees) extends through the apex and is parallel to body 425 and the Y-axis (90 degrees) extends through joint 429, second transition region 416 may be positioned within a range of 45 degrees to 75 degrees.

[0082] The composite pressure hull also includes 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 fastened to the cylindrical portion 408 and the second cylindrical portion 414. In some illustrative examples, the composite pressure hull also includes a ring 418 adhered between the cylindrical portion 408 and the second cylindrical portion 414. In some illustrative examples, the ring 418 includes a metal. In some illustrative examples, the ring 418 includes a composite material. The ring 418 may be referred to as an interface ring. The ring 418 includes a plurality of locations to receive inputs and outputs with an environment external to the composite pressure hull 400.

[0083] Now turn to Figure 5 , depicts a flow chart of a method of forming a composite pressure hull according to an illustrative embodiment. The method 500 may be performed to form a composite pressure hull, such as Figure 1 The method 500 may be performed to form a composite pressure hull 102. Figure 2 The method 500 may be used to lay and cure the monolithic half 200. Figure 3 The method 500 may be performed to form a composite pressure hull such as Figure 4 Composite pressure hull 400.

[0084] Method 500 lays up a monolithic first half of a composite pressure hull (operation 502). Method 500 lays up a monolithic second half of a composite pressure hull (operation 504). Method 500 joins the monolithic first half to the monolithic second half to form a composite pressure hull (operation 506). Thereafter, method 500 terminates.

[0085] In some illustrative examples, laying up the integral first half of the composite pressure hull includes: laying up a cylindrical portion and a dome portion on a mandrel to form a half-tank on the mandrel (operation 507). In some illustrative examples, laying up the cylindrical portion and the dome portion includes: forming a transition region including a joint between the cylindrical portion and the dome portion (operation (508). In some illustrative examples, the dome portion is laid up on a circular 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, portions of at least a plurality of cylindrical plies of the cylindrical portion extend onto the circular end of the mandrel. In some illustrative examples, the transition region is primarily formed on the circular end of the mandrel. In some illustrative examples, the transition region is formed by cylindrical plies extending onto the circular end of the mandrel.

[0086] The joint is formed simultaneously with forming 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 other. In some illustrative examples, the joint includes two scarf joints staggered through the thickness of the monolithic first half.

[0087] In some illustrative examples, forming the transition region includes alternately laying up cylindrical plies and dome-shaped plies to form a joint (operation 510). Laying up the dome-shaped plies and laying up the cylindrical plies are performed in coordination to form the transition region.

[0088] In some illustrative examples, laying up the monolithic first half of the composite pressure hull includes laying up each cylindrical ply of the cylindrical portion as a plurality of alternating paths, wherein each path in the plurality of alternating paths includes a plurality of tows (operation 512). In some illustrative examples, laying up the monolithic first half of the composite pressure hull includes laying up each dome ply of the dome portion as a plurality of alternating paths, wherein each path in the plurality of alternating paths includes a plurality of tows. In some illustrative examples, laying up the cylindrical portion and the dome portion includes a single automated fiber placement head that alternately lays up multiple groups of dome plies and multiple groups of cylindrical plies (operation 511).

[0089] In some illustrative examples, method 500 cures the monolithic first half before joining the monolithic first half to the monolithic second half (operation 513). In some illustrative examples, method 500 cures the monolithic second half before joining the monolithic first half to the monolithic second half.

[0090] In some illustrative examples, laying up the integral second half of the composite pressure hull includes laying up a second cylindrical portion and a second dome portion on a mandrel (operation 514). In some illustrative examples, laying up the second cylindrical portion and the second dome portion includes forming a transition region including a second joint between the second cylindrical portion and the second dome portion (operation 516). In some illustrative examples, laying up the integral second half of the composite pressure hull includes laying up each second cylindrical ply of the second cylindrical portion as a plurality of alternating paths, wherein each path in the plurality of alternating paths includes a plurality of tows. In some illustrative examples, laying up the integral second half of the composite pressure hull includes laying up each second dome ply of the second dome portion as a plurality of alternating paths, wherein each path in the plurality of alternating paths includes a plurality of tows.

[0091] In some illustrative examples, laying up the integral second half of the composite pressure hull is performed on the same mandrel as laying up the integral first half of the composite pressure hull (operation 518). In some illustrative examples, laying up the integral first half utilizes the same layup path as laying up the integral second half (operation 520).

[0092] In some illustrative examples, joining the monolithic first half to the monolithic second half includes adhering a ring to both the monolithic first half and the monolithic second half (operation 522). In some illustrative examples, the ring may also be referred to as a weldment ring. In some illustrative examples, the ring may also be referred to as an interface ring. In some illustrative examples, the ring includes metal. In some illustrative examples, the ring includes a composite material.

[0093] Now turn to Figure 6, depicts a flow chart of a method of forming a composite pressure hull according to an illustrative embodiment. The method 600 may be performed to form a composite pressure hull such as Figure 1 The method 600 may be performed to form a composite pressure shell 102. Figure 2 The method 500 may be used to lay and cure the monolithic half 200. Figure 3 The method 600 may be performed to form a composite pressure hull such as a Figure 4 Composite pressure hull 400.

[0094] Method 600 lays up a dome-shaped ply and a cylindrical ply on a mandrel to form a monolithic first half of a composite pressure hull (operation 602). Method 600 lays up a second dome-shaped ply and a second cylindrical ply on a mandrel to form a monolithic second half of a composite pressure hull (operation 604). Method 600 joins the monolithic first half and the monolithic second half to form the composite pressure hull (operation 606). Thereafter, method 600 terminates.

[0095] In some illustrative examples, dome top sheet and cylindrical ply are laid so 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 gap, butt joint, overlap or other. In some illustrative examples, the joint comprises two caulking joints staggered through the thickness of the monolithic first half. In some illustrative examples, laying dome top sheet and cylindrical ply comprises: laying dome top sheet and cylindrical ply (operation 609) by identical automatic fiber placement head.

[0096] In some illustrative examples, laying the dome top sheets and the cylindrical plies includes alternately laying multiple sets of dome top sheets and multiple sets of cylindrical plies to form a joint (operation 610). By alternately laying multiple sets of dome top sheets and multiple sets of cylindrical plies, a transition region is formed by the dome top sheets and the cylindrical plies.

[0097] In some illustrative examples, method 600 cures the monolithic first half of the composite pressure shell on a mandrel prior to joining the monolithic first half to the monolithic second half (operation 612). In some illustrative examples, joining the monolithic first half to the monolithic second half includes adhering a ring to both the monolithic first half and the monolithic second half (operation 614).

[0098] As used herein, the phrase "at least one," 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, but is not limited to, 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 exist. In other examples, "at least one" may be, for example, but not limited to, two of item A; one of item B; and ten of item C; four of item B and seven of item C; or other suitable combinations. Items may be specific objects, things, or categories. In other words, it means that at least one of any combination of items and number of items may be used from the list, but all items in the list are not required.

[0099] As used herein, "plurality" when used with reference to an item means one or more items. As used herein, "groups" when used with reference to an item means one or more items. Thus, a group of plies includes one or more plies.

[0100] The flowcharts and block diagrams in the depicted different embodiments illustrate the architecture, functionality and operation of some possible implementations of the devices and methods in the illustrative embodiments. In this regard, each box in the flowchart or block diagram can represent at least one of a module, a segment, a function or a part of an operation or a step.

[0101] In some alternative embodiments of the illustrative embodiments, one or more functions indicated in the blocks may not occur in the order indicated in the drawings. For example, in some cases, two blocks shown in succession may be performed substantially simultaneously, or the blocks may sometimes be performed in reverse order, depending on the functions involved. In addition, in addition to the blocks shown in the flow chart or block diagram, other blocks may be added. Some blocks may be optional. For example, operations 508 to 522 may be optional. As another example, operations 608 to 614 may be optional.

[0102] The illustrative examples provide methods and designs for composite pressure hulls. In some illustrative examples, the composite pressure hull can be used in a high pressure environment. In some illustrative examples, the composite pressure hull can be used as a submersible. In some illustrative examples, the composite pressure hull can be used to maintain high pressure. In some illustrative examples, the composite pressure hull can be used to maintain cryogenic fuel or other high pressure gas fuel. In some illustrative examples, the composite pressure hull can be used on an aircraft.

[0103] You can Figure 7 Aircraft manufacturing and service method 700 and the like are shown in Figure 8Illustrative embodiments of the present disclosure are described in the context of aircraft 800 as shown. Figure 7 , an illustration of an aircraft manufacturing and service method in block diagram form is depicted in accordance with an illustrative embodiment. During pre-production, aircraft manufacturing and service method 700 may include Figure 8 Specification and design 702 of aircraft 800 and material procurement 704 .

[0104] During production, component and subassembly manufacturing 706 and system integration 708 of aircraft 800 occurs. Thereafter, aircraft 800 may undergo certification and delivery 710 for entry into service 712. When entered into service 712 by a customer, aircraft 800 is scheduled for routine maintenance and service 714, which may include modification, reconfiguration, refurbishment, or other maintenance and service.

[0105] Each of the processes of aircraft manufacturing and service method 700 may be performed or carried out 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, but is not limited to, any number of aircraft manufacturers and major system subcontractors; a third party may include, but is not limited to, any number of suppliers, subcontractors, and vendors; and an operator may be an airline, leasing company, military entity, service organization, etc.

[0106] Reference now Figure 8 , depicts an illustration of an aircraft in block diagram form in which an illustrative embodiment may be implemented. In this example, aircraft 800 is Figure 7 Aircraft manufacturing and service method 700 is produced and may include airframe 802 having multiple systems 804 and interior 806. Examples of systems 804 include one or more of propulsion system 808, electrical system 810, hydraulic system 812, and environmental system 814. Any number of other systems may be included.

[0107] Apparatus and methods embodied herein may be employed during at least one of the stages of aircraft manufacturing and service method 700. One or more illustrative embodiments may be employed in Figure 7 The components and subassemblies of the aircraft 800 may be manufactured or used during at least one of component and subassembly manufacturing 706, system integration 708, placing into service 712, or maintenance and service 714. For example, a fuel tank or other pressure vessel of aircraft 800 may be manufactured according to the illustrative examples.

[0108] Conventional composite pressure vessels have holes at the apex of the dome for system integration of fuel, etc. An illustrative example provides a continuous dome composite structure. The cylinder and dome sections are integrated together by joints (eg, scarf joints).

[0109] The illustrative examples provide a continuous closed dome composite structure and an integrated region of cylinder fibers and dome fibers. Two composite halves are manufactured and then joined at the root of the cylinder with an annular joint. In some illustrative examples, the annular joint is metallic. The illustrative examples provide integration of continuous dome and cylinder composite parts.

[0110] This application involves the following terms:

[0111] Clause 1. A method of forming a composite pressure hull, the method comprising:

[0112] Laying down the integral first half of the composite pressure hull;

[0113] laying down the integral second half of the composite pressure hull; and

[0114] The integral first half is joined to the integral second half to form the composite pressure hull.

[0115] Clause 2. The method of Clause 1, wherein joining the integral first half to the integral second half comprises adhering a ring to both the integral first half and the integral second half.

[0116] Clause 3. The method of clause 1, wherein laying up the integral first half of the composite pressure hull comprises laying up a cylindrical portion and a dome portion on a mandrel to form a half-tank on the mandrel.

[0117] Clause 4. The method of clause 3, wherein laying down the cylindrical portion and the dome portion comprises forming a transition region comprising a joint between the cylindrical portion and the dome portion.

[0118] Clause 5. The method of clause 4, wherein forming the transition region comprises: alternately laying down cylindrical plies and dome-shaped plies to form the joint.

[0119] Clause 6. The method according to clause 4, further comprising:

[0120] The integral first half is cured prior to joining the integral first half to the integral second half.

[0121] Clause 7. The method of clause 3, wherein laying up the integral first half of the composite pressure hull comprises laying up each cylindrical ply of the cylindrical portion as a plurality of alternating paths, wherein each path in the plurality of alternating paths comprises a plurality of tows.

[0122] Clause 8. The method of Clause 3, wherein laying up the cylindrical portion and the dome portion comprises: a single automated fiber placement head alternately laying up multiple sets of dome plies and multiple sets of cylindrical plies.

[0123] Clause 9. The method of Clause 1, wherein laying up the integral second half of the composite pressure hull comprises laying up a second cylindrical portion and a second dome portion on a mandrel.

[0124] Clause 10. The method of Clause 9, wherein laying up the second cylindrical portion and the second dome portion comprises forming a transition region comprising a joint between the cylindrical portion and the dome portion.

[0125] Clause 11. The method of Clause 1, wherein laying up the integral second half of the composite pressure hull is performed on the same mandrel as laying up the integral first half of the composite pressure hull.

[0126] Clause 12. The method of clause 1, wherein laying the integral first half utilizes the same laying path as laying the integral second half.

[0127] Clause 13. A method of forming a composite pressure hull, the method comprising:

[0128] laying dome-shaped plies and cylindrical plies on a mandrel to form a unitary first half of the composite pressure hull;

[0129] laying up a second dome-shaped ply and a second cylindrical ply on the mandrel to form an integral second half of the composite pressure hull; and

[0130] The integral first half and the integral second half are joined to form the composite pressure hull.

[0131] Clause 14. The method of Clause 13, wherein 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.

[0132] Clause 15. The method of Clause 13, wherein laying up the dome-shaped top sheet and the cylindrical ply comprises laying up the dome-shaped top sheet and the cylindrical ply with the same automated fiber placement head.

[0133] Clause 16. The method of Clause 14, wherein laying down dome-shaped plies and cylindrical plies comprises: alternatingly laying down multiple sets of dome-shaped plies and multiple sets of cylindrical plies to form the joint.

[0134] Clause 17. The method according to clause 13, further comprising:

[0135] The integral first half of the composite pressure hull is cured on the mandrel prior to joining the integral first half to the integral second half.

[0136] Clause 18. The method of Clause 13, wherein joining the unitary first half to the unitary second half comprises adhering a ring to both the unitary first half and the unitary second half.

[0137] Clause 19. A composite pressure hull, comprising:

[0138] a unitary first half of the composite pressure hull, the unitary first half comprising a domed portion and a cylindrical portion with the transition region therebetween, the transition region comprising a joint formed during layup; and

[0139] The integral second half of the composite pressure hull includes a second dome portion and a second cylindrical portion with a second transition region between the second dome portion and the second cylindrical portion, the second transition region including a second joint formed during layup.

[0140] Clause 20. The composite pressure hull of Clause 19, wherein the transition region comprises cylindrical plies of the cylindrical portion and dome plies of the dome portion.

[0141] Clause 21. The composite pressure hull according to Clause 19, further comprising:

[0142] A ring is adhered between the cylindrical portion and the second cylindrical portion.

[0143] Clause 22. The composite pressure hull of Clause 21, wherein the ring comprises metal.

[0144] Clause 23. The composite pressure hull of Clause 19, wherein the integral first half has the same layup design as the integral second half.

[0145] The descriptions of different illustrative embodiments have been presented for purposes of illustration and description, and are not intended to be exhaustive or limited to the embodiments in the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. In addition, different illustrative embodiments may provide different features compared to other illustrative embodiments. The selected one or more embodiments are selected and described in order to best explain the principles of the embodiments, the practical application, and to enable those of ordinary skill in the art to understand the disclosure of various embodiments with various modifications suitable for the intended specific use.

[0146] CROSS-REFERENCE TO RELATED APPLICATIONS

[0147] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 584,684, filed on September 22, 2023, entitled “Composite Pressure Hull and Methods of Forming,” the entire contents of which are incorporated herein by reference.

Claims

1. A method for forming a composite pressure hull, the method comprising: Laying down the integral first half of the composite pressure hull; laying the integral second half of the composite pressure hull; as well as The integral first half is joined to the integral second half to form the composite pressure hull.

2. The method according to claim 1, wherein: Joining the unitary first half to the unitary second half includes adhering a ring to both the unitary first half and the unitary second half.

3. The method according to claim 1, wherein: Laying up the integral first half of the composite pressure hull includes laying up a cylindrical portion and a dome portion on a mandrel to form a half-tank on the mandrel.

4. The method according to claim 3, wherein: Laying up the cylindrical portion and the dome portion includes forming a transition region including a joint between the cylindrical portion and the dome portion.

5. The method according to claim 4, wherein: Forming the transition region includes alternately laying down cylindrical plies and dome-shaped plies to form the joint.

6. The method according to claim 4, further comprising: The integral first half is cured prior to joining the integral first half to the integral second half.

7. The method according to claim 3, wherein: Laying up the monolithic first half of the composite pressure hull includes laying up each cylindrical ply of the cylindrical portion as a plurality of alternating paths, wherein each path of the plurality of alternating paths includes a plurality of tows.

8. The method according to claim 3, wherein: Laying down the cylindrical portion and the dome portion includes a single automated fiber placement head alternately laying down multiple sets of dome plies and multiple sets of cylindrical plies.

9. A method of forming a composite pressure hull, the method comprising: laying dome-shaped plies and cylindrical plies on a mandrel to form a unitary first half of the composite pressure hull; laying up a second dome-shaped ply and a second cylindrical ply on the mandrel to form an integral second half of the composite pressure hull; as well as The integral first half and the integral second half are joined to form the composite pressure hull.

10. A composite pressure hull, comprising: a unitary first half of the composite pressure hull, the unitary first half comprising a domed portion and a cylindrical portion with the transition region therebetween, the transition region comprising a joint formed during layup; as well as The integral second half of the composite pressure hull includes a second dome portion and a second cylindrical portion with a second transition region between the second dome portion and the second cylindrical portion, the second transition region including a second joint formed during layup.

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