Unitary composite structure

Abstract

To provide a unitary composite structure and methods of forming.SOLUTION: A method of laying up a unitary composite structure comprises: laying up a plurality of dome plies on a rounded end of a mandrel using a plurality of rosettes; laying up a plurality of cylindrical plies on a cylindrical surface of the mandrel using a layup rosette independent of the plurality of rosettes; and forming a transition region comprising a joint between the plurality of dome plies and the plurality of cylindrical plies by varying lengths of the plurality of dome plies and lengths of the plurality of cylindrical plies.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 / 584,694, filed Sep. 22, 2023, and entitled "Unitary Composite Structure," which is hereby incorporated by reference in its entirety.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to composite manufacturing, and more specifically, to forming a composite structure comprising a dome portion and a cylindrical portion. [Background technology]

[0003] Weight reduction is a concern in the storage, manufacturing, or transportation of various structures. For example, it is desirable to reduce the weight of aircraft components, such as fuel tanks. To reduce the weight of a component, such as a pressure tank, it may be desirable to manufacture the component 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 bonded to 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 underwater applications. Summary of the Invention [Problem to be solved by the invention]

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

[0006] One embodiment of the present disclosure provides a method of laminating an integrated composite structure, where a plurality of dome layers are laminated to a rounded end of a mandrel using a plurality of rosettes, a plurality of cylindrical layers are laminated to a cylindrical surface of the mandrel using a lamination rosette independent of the plurality of rosettes, and a transition region is formed that comprises a junction between the plurality of dome layers and the plurality of cylindrical layers by varying the length of the plurality of dome layers and the length of the plurality of cylindrical layers.

[0007] Another embodiment of the present disclosure provides a one-piece composite structure comprising a dome portion comprising a plurality of sets of layers laminated using a plurality of rosettes, a cylindrical portion laminated using a lamination rosette independent of the plurality of rosettes, and a transition region between the dome portion and the cylindrical portion formed by varying the length of the dome layers of the dome portion and varying the length of the cylindrical layers of the cylindrical portion.

[0008] A further embodiment of the present disclosure provides a method of laminating a composite structure. A plurality of dome layers are laminated to a rounded end of a mandrel. Laminating the plurality of dome layers includes: laminating a first set of layers to the rounded end of the mandrel at a zero degree fiber angle using a first rosette; laminating a second set of layers to the rounded end of the mandrel at a zero degree fiber angle using a second rosette offset from the first rosette; and laminating a third set of layers to the rounded end of the mandrel at a zero degree fiber angle using a third rosette offset from both the first and second rosettes. A plurality of cylindrical layers are laminated to a cylindrical surface of the mandrel in contact with the plurality of dome layers. The lengths of the plurality of dome layers and the plurality of cylindrical layers are varied to form a joint between the plurality of dome layers and the plurality of cylindrical layers.

[0009] The above features and functions may be implemented independently in various embodiments of the present disclosure, and the above features and functions may be combined in 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 be best understood with reference to the following detailed description of 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 an illustration of a block diagram of a manufacturing environment in accordance with an illustrative embodiment. [Diagram 2] FIG. 1 is an illustration of an isometric view of a one-piece composite structure on a mandrel in accordance with an illustrative embodiment; [Diagram 3] 1 is an illustration of a front view of layers of a dome portion of a composite structure in accordance with an illustrative embodiment; [Figure 4] 1 is an illustration of a front view of layers of a dome portion of a composite structure in accordance with an illustrative embodiment; [Diagram 5] 1 is an illustration of a front view of layers of a dome portion of a composite structure in accordance with an illustrative embodiment; [Figure 6] FIG. 1 is an illustration of an isometric view of composite plies stacked on a mandrel in accordance with an illustrative embodiment; [Figure 7] FIG. 1 is an illustration of an isometric view of composite plies stacked on a mandrel in accordance with an illustrative embodiment; [Figure 8] 1 illustrates a flowchart of a method for laying up a one-piece composite structure in accordance with an illustrative embodiment. [Figure 9] 1 is a flowchart of a method for laying up a composite structure in accordance with an illustrative embodiment. [Figure 10] 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 11] 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] The illustrative embodiments take into account one or more considerations. The illustrative embodiments take into account that current dome manufacturing uses standard rosette orientation methods, and that the domes and cylinders are manufactured separately. The illustrative embodiments recognize and take into account that large domes can be steered with a cylindrical (standard orientation) layer into the dome area. The illustrative embodiments recognize and take into account that the steering radius using standard rosette orientation methods for smaller dome structures will be small enough to cause undesirable effects on the dome. The illustrative embodiments also recognize and take into account that traditional fiber placement paths transitioning to the dome surface have singularities at the poles of the dome, resulting in unacceptable results. The illustrative embodiments provide a forming method and a one-piece composite structure that can be formed with smaller dome diameters without undesirable effects. The illustrative embodiments provide a forming method and a one-piece composite structure that is formed without singularities at the poles. The illustrative embodiments provide a method of forming a one-piece composite structure having a semi-capsule shape.

[0013] 1, an illustration of a block diagram of a manufacturing environment is shown in accordance with an illustrative embodiment. A one-piece 104 composite structure 102 is manufactured in a manufacturing environment 100. The one-piece 104 composite structure 102 includes a dome portion 106 comprising a plurality of sets of plies 109 laminated using a plurality of rosettes 110 and a cylindrical portion 112 laminated with a lamination rosette 114 independent of the plurality of rosettes 110. In some illustrative examples, the lamination rosette 114 is projected onto a surface such that the y-axis extends longitudinally along a mandrel 118 and the x-axis extends circumferentially.

[0014] The stacked rosettes 114 of the cylindrical portion 112 comprise the axes of a reference coordinate system. In some exemplary embodiments, the X-axis can be used for the zero reference. Any axis of the stacked rosettes 114 can be used for the zero reference. The axis can be anywhere in space. In some exemplary embodiments, the axis is an axis of symmetry about the mandrel 118.

[0015] In some demonstrative examples, the reference axis is projected onto the cylindrical surface 120 at a point, defining the zero direction of the cylindrical surface 120. The fiber angle is then rotated from the zero projection to that local point about the surface normal to determine the path direction at that point.

[0016] The one-piece 104 composite structure 102 is laid up on a mandrel 118. The mandrel 118 has a rounded end 116 and a cylindrical surface 120. The dome portion 106 is laid up on the rounded end 116 of the mandrel 118. The cylindrical portion 112 is laid up on the cylindrical surface 120.

[0017] The dome portion 106 comprises a plurality of dome layers 108 laminated to the rounded end 116 of the mandrel 118. The plurality of dome layers 108 are completely laminated to the rounded end 116 of the mandrel 118. The cylindrical portion 112 comprises a plurality of cylindrical layers 168 laminated to the cylindrical surface 120. At least one cylindrical layer of the plurality of cylindrical layers 168 extends to the rounded end 116 of the mandrel 118. The portion of the plurality of cylindrical layers 168 that extends to the rounded end 116 forms a transition region 184.

[0018] In some exemplary embodiments, a cylindrical layer of the plurality of cylindrical layers 168 is a composite layer that generally begins at the cylindrical surface 120 and transitions to a portion of the rounded end 116 of the mandrel 118. In some exemplary embodiments, many of the plurality of cylindrical layers 168 continue to the rounded end 116 of the mandrel 118. In some exemplary embodiments, all of the plurality of cylindrical layers 168 continue to the rounded end 116 of the mandrel 118. The material properties of the plurality of dome layers 108 may be undesirable at the edge of the rounded end 116 where the rounded end 116 meets the cylindrical surface 120. Thus, the plurality of dome layers 108 may be laminated to the rounded end 116 and terminate before intersecting with the cylindrical surface 120.

[0019] In some exemplary embodiments, each rosette in the plurality of rosettes 110 has a Z-axis that extends to the apex 115 of the rounded end 116 of the mandrel 118. In some exemplary embodiments, each rosette in the plurality of rosettes 110 has a Z-axis that extends parallel to the cylindrical surface 120 of the mandrel 118. In some exemplary embodiments, each rosette in the plurality of rosettes 110 has a Z-axis that is perpendicular to the plurality of dome layers 108 that cover the apex 115 of the rounded end 116 of the mandrel 118.

[0020] The plurality of rosettes 110 comprises rosettes rotated about a Z-axis extending into or away from apex 115. In some exemplary embodiments, the rotation about the Z-axis may be referred to as "clocking." In some exemplary embodiments, the plurality of rosettes 110 comprises a reference rosette 111 and a number of rosettes clocked about the Z-axis relative to the reference rosette. In some exemplary embodiments, the reference rosette is positioned to lay down a 0 degree fiber angle ply within the composite structure 102.

[0021] In some exemplary embodiments, the reference rosette 111 is oriented such that its Z-axis is perpendicular to the apex 115 of the rounded end 116 of the mandrel 118. In some exemplary embodiments, the reference rosette 111 is oriented such that its Z-axis is parallel to the longitudinal axis of the cylindrical surface 120 of the mandrel 118. The x- and y-axes of the reference rosette 111 can have any desired orientation. In some exemplary embodiments, the reference rosette 111 is oriented such that one axis is parallel to the Z-axis of the stacked rosette 114. In some exemplary embodiments, the reference rosette has a Y-axis perpendicular to the manufacturing floor. In some exemplary embodiments, the reference rosette has an X-axis parallel to the manufacturing floor.

[0022] The rosettes orient the plurality of tows 122 for stacking by a composite tow placement head 124. Prior to placing the plurality of tows 122 on the mandrel 118, the composite tow placement head 124 uses each rosette in the plurality of rosettes 110 to position itself relative to the mandrel 118.

[0023] The plurality of rosettes 110 can include any desired quantity of rosettes 164. In some exemplary embodiments, the plurality of rosettes 110 includes at least four rosettes. As shown, the plurality of rosettes 110 includes six rosettes, namely, a first rosette 126, a second rosette 128, a third rosette 130, a fourth rosette 132, a fifth rosette 134, and a sixth rosette 136. In some exemplary embodiments, the plurality of rosettes 110 includes more than six rosettes. In some exemplary embodiments, the dome portion 106 includes a quantity of fiber angles equal to the quantity of rosettes 164 in the plurality of rosettes 110.

[0024] In some exemplary embodiments, the spacing between each of the plurality of rosettes 110 is determined by dividing 180 degrees into equal increments to set the clocking offset 166 for the plurality of rosettes 110. In one exemplary embodiment, if the quantity of rosettes 164 comprises four rosettes, the clocking offset 166 is 180 / 4 degrees or 45 degrees. In this exemplary embodiment, the plurality of rosettes 110 comprises 0 degrees, 45 degrees, 90 degrees, and 135 degrees. In one exemplary embodiment, if the quantity of rosettes 164 comprises six rosettes, the clocking offset 166 is 180 / 6 degrees or 30 degrees. In this exemplary embodiment, the plurality of rosettes 110 comprises 0 degrees, 30 degrees, 60 degrees, 90 degrees, 120 degrees, and 150 degrees. In another exemplary embodiment, if the quantity of rosettes 164 comprises eight rosettes, the clocking offset 166 is 180 / 8 degrees or 22.5 degrees. In this illustrative embodiment, the plurality of rosettes 110 comprises 0 degrees, 22.5 degrees, 45 degrees, 67.5 degrees, 90 degrees, 112.5 degrees, 135 degrees, and 157.5 degrees.

[0025] The dome portion 106 includes a plurality of dome layers 108. The plurality of dome layers includes a plurality of sets of layers 109.

[0026] The multiple set of layers 109 comprises a first set of layers 138, a second set of layers 140, a third set of layers 142, a fourth set of layers 144, a fifth set of layers 146, and a sixth set of layers 148. Although the terms "first," "second," "third," "fourth," "fifth," and "sixth" are used, these terms do not indicate an order or sequence. Each of the first set of layers 138, the second set of layers 140, the third set of layers 142, the fourth set of layers 144, the fifth set of layers 146, and the sixth set of layers 148 can be stacked in any desired order. Additionally, each of the first set of layers 138, the second set of layers 140, the third set of layers 142, the fourth set of layers 144, the fifth set of layers 146, and the sixth set of layers 148 can have any desired number of layers per set. Although the plurality of dome layers 108 is illustrated as comprising the first set of layers 138, the second set of layers 140, the third set of layers 142, the fourth set of layers 144, the fifth set of layers 146, and the sixth set of layers 148, any desired number of sets of layers can be included in the plurality of dome layers 108.

[0027] In some demonstrative embodiments, each dome layer of the plurality of dome layers 108 comprises a plurality of alternating paths 123 of a plurality of tows 122. Each path of the plurality of alternating paths 123 comprises a plurality of tows 122. In some demonstrative embodiments, the plurality of tows 122 comprises 16 tows. The plurality of tows 122 may comprise any desired quantity of tows.

[0028] Each set of dome layers is laminated using a respective rosette of the plurality of rosettes 110. The first set of layers 138 is laminated using the first rosette 126. The first set of layers 138 is laminated at a zero degree fiber angle relative to the first rosette 126. The first rosette 126 may be any desired rosette of the plurality of rosettes 110. By laminating the first set of layers 138 with the first rosette 126, the first set of layers 138 has an effective first fiber angle 150. The first set of layers 138 has an effective first fiber angle 150 relative to the reference rosette 111. In some exemplary embodiments, the first rosette 126 is the same as the reference rosette 111. In some exemplary embodiments, when the first rosette 126 is the same as the reference rosette 111, the effective first fiber angle 150 is zero degrees. In some exemplary embodiments, when first rosette 126 is a rosette other than reference rosette 111, effective first fiber angle 150 is an angle other than 0 degrees.

[0029] The second set of plies 140 are stacked using the second rosettes 128. The second set of plies 140 are stacked at 0 degrees relative to the second rosettes 128. By stacking the second set of plies 140 with the second rosettes 128, the second set of plies 140 has a valid second fiber angle 152. In some exemplary embodiments, the second rosettes 128 are clocked relative to the reference rosettes 111. When the second rosettes 128 are clocked relative to the reference rosettes 111, the valid second fiber angle 152 is a non-zero fiber angle relative to the reference rosettes 111. As shown, the quantity of rosettes 164 is six, and the valid second fiber angle 152 can be one of 30 degrees, 60 degrees, 90 degrees, 120 degrees, or 150 degrees. In some exemplary embodiments, the valid second fiber angle 152 is 30 degrees.

[0030] The third set of plies 142 are stacked using the third rosette 130. The third set of plies 142 are stacked at 0 degrees relative to the third rosette 130. By stacking the third set of plies 142 with the third rosette 130, the third set of plies 142 has a valid third fiber angle 154. In some exemplary embodiments, the third rosette 130 is clocked relative to the reference rosette 111. When the third rosette 130 is clocked relative to the reference rosette 111, the valid third fiber angle 154 is a non-zero fiber angle relative to the reference rosette 111. As shown, the quantity of rosettes 164 is six, and the valid third fiber angle 154 can be one of 30 degrees, 60 degrees, 90 degrees, 120 degrees, or 150 degrees. In some exemplary embodiments, the valid third fiber angle 154 is 60 degrees. In some exemplary embodiments, the fiber angles of the dome portions 106 are offset approximately equally from one another.

[0031] The fourth set of plies 144 are stacked using the fourth rosette 132. The fourth set of plies 144 are stacked at 0 degrees relative to the fourth rosette 132. By stacking the fourth set of plies 144 with the fourth rosette 132, the fourth set of plies 144 has a valid fourth fiber angle 156. In some exemplary embodiments, the fourth rosette 132 is clocked relative to the reference rosette 111. When the fourth rosette 132 is clocked relative to the reference rosette 111, the valid fourth fiber angle 156 is a non-zero fiber angle relative to the reference rosette 111. As shown, the quantity of rosettes 164 is six, and the valid fourth fiber angle 156 can be one of 30 degrees, 60 degrees, 90 degrees, 120 degrees, or 150 degrees. In some exemplary embodiments, the valid fourth fiber angle 156 is 90 degrees.

[0032] The fifth set of plies 146 are stacked using the fifth rosette 134. The fifth set of plies 146 are stacked at 0 degrees relative to the fifth rosette 134. By stacking the fifth set of plies 146 with the fifth rosette 134, the fifth set of plies 146 has a valid fifth fiber angle 158. In some exemplary embodiments, the fifth rosette 134 is clocked relative to the reference rosette 111. When the fifth rosette 134 is clocked relative to the reference rosette 111, the valid fifth fiber angle 158 is a non-zero fiber angle relative to the reference rosette 111. As shown, the quantity of rosettes 164 is six, and the valid fifth fiber angle 158 can be one of 30 degrees, 60 degrees, 90 degrees, 120 degrees, or 150 degrees. In some exemplary embodiments, the valid fifth fiber angle 158 is 120 degrees.

[0033] The sixth set of plies 148 are stacked using the sixth rosette 136. The sixth set of plies 148 are stacked at 0 degrees relative to the sixth rosette 136. By stacking the sixth set of plies 148 with the sixth rosette 136, the sixth set of plies 148 has a valid sixth fiber angle 160. In some exemplary embodiments, the sixth rosette 136 is clocked relative to the reference rosette 111. When the sixth rosette 136 is clocked relative to the reference rosette 111, the valid sixth fiber angle 160 is a non-zero fiber angle relative to the reference rosette 111. As shown, the quantity of rosettes 164 is six, and the valid sixth fiber angle 160 can be one of 30 degrees, 60 degrees, 90 degrees, 120 degrees, or 150 degrees. In some exemplary embodiments, the valid sixth fiber angle 160 is 150 degrees.

[0034] Each of the first effective fiber angle 150, the second effective fiber angle 152, the third effective fiber angle 154, the fourth effective fiber angle 156, the fifth effective fiber angle 158, and the sixth effective fiber angle 160 is laid using a respective rosette. The use of a respective rosette reduces or eliminates at least one steering when laying the dome section 106. Each of the first effective fiber angle 150, the second effective fiber angle 152, the third effective fiber angle 154, the fourth effective fiber angle 156, the fifth effective fiber angle 158, and the sixth effective fiber angle 160 is laid without steering the fibers. Steering the dome section 106 may result in one edge of the tow being shorter or longer than the other edge of the tow. By reducing or eliminating steering, inconsistencies such as pockets, wrinkling, or fiber lift are also reduced or eliminated in the dome portion 106 .

[0035] In some exemplary embodiments, the multiple dome layers 108 are stacked such that an approximately equal number of layers are stacked at each available fiber angle. In some exemplary embodiments, the multiple dome layers 108 are stacked such that an approximately equal number of layers are stacked in each rosette of the multiple rosettes 110.

[0036] The cylindrical portion 112 is laminated with a lamination rosette 114. The lamination rosette 114 is separate from the plurality of rosettes 110. Each of the plurality of cylindrical plies 168 of the cylindrical portion 112 is laminated using a lamination rosette 114. Fiber steering can be performed to laminate the plurality of different fiber angles of the cylindrical portion 112 with the lamination rosette 114. In some exemplary embodiments, fiber steering occurs when laminating a section of the cylindrical portion 112 having a non-zero ply angle that extends to the rounded end 116 of the mandrel 118.

[0037] The first set of cylindrical plies 170 are laid up according to the layup rosettes 114 to have a fiber angle 171. The fiber angle 171 can have any desired fiber angle for the design of the composite structure 102. In some illustrative examples, the fiber angle 171 is selected from 0 degrees, 45 degrees, and 90 degrees.

[0038] A second set of cylindrical plies 172 are laid up according to layup rosettes 114 to have fiber angle 173. Fiber angle 173 may be any desired fiber angle for the design of composite structure 102. In some illustrative examples, fiber angle 173 may be the same as fiber angle 171. In some illustrative examples, fiber angle 173 is different from fiber angle 171.

[0039] A third set of cylindrical plies 174 are stacked according to the stacked rosettes 114 at a fiber angle 175. A fourth set of cylindrical plies 176 are stacked according to the stacked rosettes 114 at a fiber angle 177. A fifth set of cylindrical plies 178 are stacked according to the stacked rosettes 114 at a fiber angle 179. A sixth set of cylindrical plies 180 are stacked according to the stacked rosettes 114 at a fiber angle 181.

[0040] In some exemplary embodiments, multiple cylindrical layers 168 are stacked such that each cylindrical layer overlaps a conventional dome layer. In some exemplary embodiments, a first set of cylindrical layers 170 are stacked over the edges of the first set of layers 138.

[0041] The one-piece 104 composite structure 102 further comprises a transition region 184 between the dome portion 106 and the cylindrical portion 112 formed by varying the length 137 of the dome layers 108 of the dome portion 106 and varying the length 182 of the cylindrical layers 168 of the cylindrical portion 112. In some exemplary embodiments, the varying the length 137 of the dome layers 108 of the dome portion 106 and the varying the length 182 of the cylindrical layers 168 of the cylindrical portion 112 form a joint 186 in the transition region 184. In some exemplary embodiments, the transition region 184 comprises the joint 186. In some exemplary embodiments, the joint 186 takes the form of a scarf joint 188.

[0042] The transition region 184 is laminated to the rounded end 116 of the mandrel 118. The transition region 184 may be located at any desired portion of the rounded end 116.

[0043] The dome portion 106 of the composite structure 102 of the one-piece 104 does not have a central hole at the apex 139 of the dome portion 106. In some exemplary embodiments, for a localization system having an X-axis (0 degrees) extending parallel to the body 195 through the apex 139 and a Y-axis (90 degrees) extending through the joint 193, the transition region 184 can be positioned within a range of 45 degrees to 75 degrees. In some exemplary embodiments, the transition region 184 is positioned within a range of 60 degrees to 75 degrees. In some exemplary embodiments, the transition region 184 is positioned to control the fiber angle gap 135. In some exemplary embodiments, the transition region 184 is positioned to maintain the fiber angle gap 135 at or below 45 degrees.

[0044] In some exemplary embodiments, the transition region 184 comprises a double scarf junction formed by alternating sets of cylindrical layers and sets of dome layers. In some exemplary embodiments, the transition region 184 comprises a double scarf junction formed by alternating sets of dome layers, such as the first set of layers 138, the second set of layers 140, or any other desired set of the plurality of dome layers 108, with sets of cylindrical layers, such as the first set of cylindrical layers 170, the second set of cylindrical layers 172, or any other desired set of the plurality of cylindrical layers 168.

[0045] In some exemplary embodiments, the joint 186 is formed by a series of steps that abut the layers of the dome layers 108 and the layers of the cylinder layers 168. In some exemplary embodiments, the joint 186 comprises slightly gapping the layers of the dome layers 108 and the layers of the cylinder layers 168.

[0046] In some exemplary embodiments, transition region 184 has a series of joints between layers of the same thickness. In these exemplary embodiments, transition region 184 includes at least one additional joint in addition to joint 186. In some exemplary embodiments, transition region 184 includes a set of joints, including joint 186, that are staggered through the thickness of composite structure 102 of one piece 104 and separated to minimize repetition anywhere within transition region 184.

[0047] After laminating the cylindrical portion 112, the dome portion 106, and the transition area 184 formed by the dome portion 106 and the cylindrical portion 112, the composite structure 102 is cured. The dome portion 106 and the cylindrical portion 112 are co-cured. In some illustrative examples, the composite structure 102 can be described as having the shape of a half-capsule 190.

[0048] Half capsule 190 comprises a body 195 and a cap 191 having a junction 193 between body 195 and cap 191. In some exemplary embodiments, junction 193 is a point of change in curvature. In some exemplary embodiments, body 195 is formed entirely by cylindrical portion 112. In some exemplary embodiments, cap 191 includes transition region 184. In some exemplary embodiments, cap 191 comprises dome portion 106, transition region 184, and a portion of cylindrical portion 112.

[0049] Composite structure 102 may be a portion of a composite pressure hull 192. In some illustrative examples, composite structure 102 may take the form of one of a unitary first half 194 or a unitary second half 196 of composite pressure hull 192. Composite pressure hull 192 includes unitary first half 194 and unitary second half 196 joined by a ring 198.

[0050] The fiber angle gap 135 is a measurement of how dispersed the fibers are at some points. The fiber angle gap 135 has a maximum value of approximately 180 degrees. The fiber angle gap 135 is a measurement of the fiber angle through the thickness. In some exemplary embodiments, the fiber angle gap 135 is the maximum angle between the fiber angles at any point on the surface. An undesirably large fiber angle gap can have an undesirable effect on the strength of the composite structure 102. In some exemplary embodiments, it is desirable to reduce the fiber angle gap 135 through the design of the composite structure 102. In some exemplary embodiments, the fiber angle gap 135 increases moving from the apex 115 toward the connection between the rounded end 116 and the cylindrical surface 120.

[0051] The fiber angle gap 135 can be controlled by the stacking order of the dome layers 108, the size of the dome layers 108, and the number of rosettes 164. Stacking the dome layers 108 with shorter dome layers can reduce the fiber angle gap 135. Selecting which of the cylindrical layers 168 extend further into the rounded end 116 of the mandrel 118 can also be used to reduce the fiber angle gap 135. Selecting a particular fiber angle of the cylindrical portion 112 that extends further into the rounded end 116 of the mandrel 118 can also be used to reduce the fiber angle gap 135. Stacking the dome layers 108 with rosettes 110 having a greater number of rosettes 164 can reduce the fiber angle gap 135. In some exemplary embodiments, the clocking offset 166 is selected to reduce the fiber angle gap 135. In some exemplary embodiments, the fiber angle of the plurality of dome layers 108 and the desired structural requirements of the composite structure 102 influence the length 137 of the plurality of dome layers 108. In some exemplary embodiments, the fiber angle gap 135 of the dome portion 106 is desirably 45 degrees or less. In some exemplary embodiments, the number of rosettes 164 can be increased to reduce the fiber angle gap 135. In some exemplary embodiments, some of the cylindrical layers 168 can be stretched further into the rounded end 116 of the mandrel 118 to reduce the fiber angle gap 135.

[0052] The illustration of manufacturing environment 100 in FIG. 1 is not meant to imply physical or architectural limitations to the manner in which an example embodiment may be implemented. Other components may be used in addition to or in place of the illustrated components. Some components may be required. Also, the blocks are illustrated to illustrate some functional components. One or more of these blocks may be combined, divided, or combined and then divided into different blocks when implemented in an example embodiment.

[0053] For example, in some illustrative embodiments, there are more than six sets of layers in the plurality of dome layers 108. The plurality of dome layers 108 may comprise any desired number of layers divided into any desired sets.

[0054] Additionally, although composite structure 102 has been described as having a shape of multiple cylindrical layers 168 and half capsules 190, composite structure 102 may have other desired shapes. In some illustrative examples, the non-cylindrical portion may be connected to dome portion 106 by a transition region 184. In some illustrative examples, one of a conical, elliptical, or other contoured portion is present in place of cylindrical portion 112. In other words, mandrel 118 may have other shapes besides cylindrical surface 120 while still having rounded ends 116. In these illustrative examples, mandrel 118 may be used to form composite structure 102 with a body having a shape other than a cylindrical shape.

[0055] Additionally, for some non-cylindrical shapes, the transition region 184 may be located at least partially in the body of the composite structure. In these illustrative examples, the transition region 184 may be located at the rounded end 116 or any desired portion of the mandrel body depending on the steering, angular gap, angular deviation, and other characteristics of the design of the composite structure.

[0056] 2, an illustration of an isometric view of a one-piece composite structure on a mandrel is shown in accordance with an illustrative embodiment. One-piece composite structure 202 is shown in view 200. One-piece composite structure 202 is a physical implementation of one-piece 104 composite structure 102 of FIG.

[0057] The one-piece composite structure 202 comprises a dome portion 204 and a cylindrical portion 206. The dome portion 204 comprises a plurality of sets of plies laminated using a plurality of rosettes. The cylindrical portion 206 is laminated with lamination rosettes that are separate from the dome portion 204.

[0058] The one-piece composite structure 202 further comprises a transition region 208 between the dome portion 204 and the cylindrical portion 206 formed by varying lengths of the multiple dome layers 216 in the dome portion 204 and varying lengths of the multiple cylindrical layers 218 in the cylindrical portion transitioning to the dome portion 204. In some example embodiments, the transition region 208 comprises a double scarf junction formed by alternating sets of cylindrical layers and sets of dome layers.

[0059] In some exemplary embodiments, dome portion 204 comprises a quantity of fiber angles equal to the quantity of rosettes in the plurality of rosettes. In some exemplary embodiments, the fiber angles of dome portion 204 are approximately equally offset from one another. In some exemplary embodiments, the plurality of rosettes comprises at least four rosettes. In some exemplary embodiments, the fiber angle gap of dome portion 204 is desirably 45 degrees or less.

[0060] The dome portion 204 is laminated to the rounded end 212 of the mandrel 210. The cylindrical portion 206 is laminated to the cylindrical surface 214 of the mandrel 210. Some of the cylindrical layers extend over a portion of the rounded end 212 of the mandrel 210 to form a transition region 208.

[0061] Although the one-piece composite structure 202 is described as having multiple cylindrical layers forming the cylindrical portion 206, the composite structure may be layered with example embodiments having a non-cylindrical body. In some example embodiments, the composite structure may be one of a conical, elliptical, or other contoured portion instead of the cylindrical portion 206.

[0062] Referring now to FIG. 3, a diagram of a front view of a dome layer of a dome portion of a composite structure is shown in accordance with an exemplary embodiment. The dome layer 302 of FIG. 300 is a physical implementation of one of the plurality of dome layers 108 of FIG. 1. In some exemplary examples, the dome layer 302 has a larger surface area than a layer of the plurality of dome layers 108 of FIG. 1. The surface area of ​​the dome layer 302 can be adjusted based on the design of the composite structure and the desired fiber angle gap. In some exemplary examples, the dome layer 302 is a physical implementation of a layer of the first set of layers 138 of FIG. 1. The dome layer 302 can be present in the unitary composite structure 202 of FIG. 2. The dome layer 302 comprises a plurality of alternating paths 304 of a plurality of tows 306. Each path of the plurality of alternating paths 304 comprises a plurality of tows 306. In some exemplary examples, the plurality of tows 306 comprises 16 tows. The plurality of tows 306 comprises any desired quantity of tows.

[0063] The plurality of alternating paths 304 are stacked using rosette 308. Rosette 308 is a physical implementation of any desired rosette of the plurality of rosettes 110 of FIG. 1. In some exemplary embodiments, rosette 308 is a physical implementation of first rosette 126 of FIG. 1. In this exemplary embodiment, rosette 308 may be referred to as a reference rosette. In some exemplary embodiments, rosette 308 is oriented such that its Z-axis is perpendicular to the apex of the rounded end of the mandrel. In some exemplary embodiments, rosette 308 is oriented such that its Z-axis is parallel to the longitudinal axis of the cylindrical surface of the mandrel. The x-axis and y-axis of rosette 308 may have any desired orientation. In some exemplary embodiments, rosette 308 is oriented such that one axis is parallel to the Z-axis of a cylindrical rosette (not shown). A cylindrical rosette is a rosette used to stack cylindrical portions of a one-piece composite structure.

[0064] In some exemplary embodiments, rosette 308 is oriented such that one axis is perpendicular to the manufacturing floor and one axis is parallel to the manufacturing floor, hi some exemplary embodiments, rosette 308 is oriented such that the Z axis is parallel to the cylindrical surface of the mandrel.

[0065] The dome layer 302 has an angle of 0 degrees relative to the rosette 308. The dome layer 302 is stacked without steering the multiple tows 306. The dome layer 302 can be stacked without steering the multiple tows 306 by having the dome layer 302 at an angle of 0 degrees relative to the rosette 308.

[0066] Referring now to FIG. 4, a diagram of a front view of a dome layer of a dome portion of a composite structure is shown in accordance with an exemplary embodiment. The dome layer 402 of FIG. 400 is a physical implementation of one of the plurality of dome layers 108 of FIG. 1. In some exemplary examples, the dome layer 402 has a larger surface area than a layer of the plurality of dome layers 108 of FIG. 1. The surface area of ​​the dome layer 402 can be adjusted based on the design of the composite structure and the desired fiber angle gap. In some exemplary examples, the dome layer 402 is a physical implementation of a layer of the second set of layers 140 of FIG. 1. The dome layer 402 can be present in the unitary composite structure 202 of FIG. 2. The dome layer 402 comprises a plurality of alternating paths 404 of a plurality of tows 406. Each path of the plurality of alternating paths 404 comprises a plurality of tows 406.

[0067] The plurality of alternating paths 404 are stacked using rosette 408. Rosette 408 is a physical implementation of any desired rosette of the plurality of rosettes 110 of FIG. 1. In some illustrative examples, rosette 308 is a physical implementation of second rosette 128 of FIG. 1. In this illustrative example, rosette 408 is rotated about the Z-axis relative to rosette 308. In some illustrative examples, the rotation about the Z-axis may be referred to as "clocking." In this illustrative example, rosette 408 is clocked about 22.5 degrees relative to rosette 308.

[0068] The dome layer 402 has a 0 degree angle relative to the rosette 408. The dome layer 402 is stacked without steering the tows 406 to stack the dome layer 402 at a 0 degree angle relative to the rosette 408. The dome layer 402 has an effective ply angle of 22.5 degrees relative to the rosette 408 without steering the tows 406. The dome layer 402 may be referred to as a 22.5 degree ply.

[0069] Referring now to FIG. 5, a diagram of a front view of a dome layer of a dome portion of a composite structure is shown in accordance with an exemplary embodiment. The dome layer 502 of FIG. 500 is a physical implementation of one of the plurality of dome layers 108 of FIG. 1. In some exemplary examples, the dome layer 502 has a larger surface area than a layer of the plurality of dome layers 108 of FIG. 1. The surface area of ​​the dome layer 502 can be adjusted based on the design of the composite structure and the desired fiber angle gap. In some exemplary examples, the dome layer 502 is a physical implementation of a layer of the third set of layers 142 of FIG. 1. The dome layer 502 can be present in the unitary composite structure 202 of FIG. 2. The dome layer 502 comprises a plurality of alternating paths 504 of a plurality of tows 506. Each path of the plurality of alternating paths 504 comprises a plurality of tows 506.

[0070] The plurality of alternating paths 504 are stacked using rosette 508. Rosette 508 is a physical implementation of any desired rosette of the plurality of rosettes 110 of FIG. 1. In some illustrative examples, rosette 508 is a physical implementation of third rosette 130 of FIG. 1. In this illustrative example, rosette 508 is clocked relative to rosette 308. In this illustrative example, rosette 508 is clocked at approximately 45 degrees relative to rosette 308.

[0071] The dome layer 502 has a fiber angle of 0 degrees relative to the rosette 508. The dome layer 502 is laid up without steering the tows 506. The dome layer 502 has an effective ply angle of 45 degrees relative to the rosette 308 without steering the tows 506. The dome layer 502 may be referred to as a 45 degree ply.

[0072] 6, there is shown an isometric view diagram of composite plies stacked on a mandrel according to an exemplary embodiment. In diagram 600, stack 601 comprises a plurality of plies 602 stacked on a mandrel 604. Stack 601 comprises at least one cylindrical ply of the plurality of cylindrical plies 168 of FIG. 1 and at least one dome layer of the plurality of dome layers 108 of FIG. 1. Stack 601 may be a portion of unitary composite structure 202 of FIG. 2. Dome layer 302 of FIG. 3 may be a ply of stack 601. Dome layer 402 of FIG. 4 may be a ply of stack 601. Dome layer 502 of FIG. 5 may be a ply of stack 601.

[0073] The plurality of layers 602 includes a dome layer 606 and a cylindrical layer 608. In this illustrative example, the cylindrical layer 608 is a 0 degree layer. A transition region 610 is formed by the interaction between the dome layer at the mandrel rounded end 614 of the mandrel 604 and the cylindrical layer at the cylindrical surface 616.

[0074] The dome layer 606 is laminated to the rounded end 614 of the mandrel 604 using rosette 612. The rosette 612 is clocked relative to a reference rosette 618. By clocking the rosette 612 relative to the reference rosette 618, the dome layer 606 has an effective fiber angle of approximately 22.5 degrees. By laminating the dome layer 606 at zero fiber angle relative to the rosette 612, the dome layer 606 is laminated at an effective fiber angle of 22.5 degrees without the use of fiber steering.

[0075] The dome portion of the one-piece composite structure comprises multiple sets of dome layers stacked using multiple rosettes on the rounded end 614 of the mandrel 604. Dome layer 606 is one layer of the multiple sets of dome layers of the dome portion.

[0076] The cylindrical layer 608 is laminated with lamination rosettes independent of rosette 612 and parallel to the cylindrical axis of symmetry. The cylindrical layer 608 is laminated with lamination rosettes independent of its rosettes to laminate the dome portion to the rounded end 614 of the mandrel 604. As shown in FIG. 600, the cylindrical layer 608 is laminated to the edge of the dome layer 606.

[0077] In some illustrative examples, after the cylindrical layer 608 is laminated, another cylindrical layer can be laminated over at least a portion of the cylindrical layer 608. The another cylindrical layer can have any desired fiber angle according to the design of the integrated composite structure. The another cylindrical layer is laminated using the same lamination rosette as the cylindrical layer 608.

[0078] In some exemplary embodiments, after the cylindrical layer 608 is laminated, another dome layer can be laminated on at least a portion of the cylindrical layer 608. In some exemplary embodiments, after the cylindrical layer 608 is laminated, another dome layer can be laminated against the cylindrical layer 608 or with a small gap to the cylindrical layer 608. The another dome layer can have any desired fiber angle according to the design of the one-piece composite structure. In some exemplary embodiments, the another dome layer can be laminated using rosette 612. In some exemplary embodiments, the another dome layer can be laminated using a rosette different from rosette 612.

[0079] A transition region can be formed between the dome and cylindrical portions formed by varying the length of the dome layers in the dome portion and varying the length of the cylindrical layers in the cylindrical portion. In some example embodiments, the next cylindrical layer stacked over a portion of the cylindrical layer 608 is shorter than the cylindrical layer 608 and does not cover as much of the rounded end 614 of the mandrel 604.

[0080] In some exemplary embodiments, the transition region comprises a double scarf joint formed by a pair of alternating cylindrical plies and dome plies. The transition region can include any desired number of joints. In some exemplary embodiments, the transition region comprises several joints that are staggered through a thickness of the one-piece composite structure.

[0081] 7, there is shown an isometric view diagram of composite plies stacked on a mandrel according to an exemplary embodiment. In diagram 700, stack 701 comprises a plurality of plies 702 stacked on a mandrel 704. Stack 701 comprises at least one cylindrical ply of the plurality of cylindrical plies 168 of FIG. 1 and at least one dome layer of the plurality of dome layers 108 of FIG. 1. Stack 701 may be a portion of unitary composite structure 202 of FIG. 2. Dome layer 302 of FIG. 3 may be a ply of stack 701. Dome layer 402 of FIG. 4 may be a ply of stack 701. Dome layer 502 of FIG. 5 may be a ply of stack 701.

[0082] The plurality of layers 702 includes a dome layer 706 and a cylindrical layer 708. In this illustrative example, the cylindrical layer 708 is a 90 degree layer. A transition region 710 is formed by the interaction between the dome layer at the mandrel rounded end 714 of the mandrel 704 and the cylindrical layer at the cylindrical surface 716.

[0083] The dome layer 706 is laminated to the rounded end 714 of the mandrel 704 using rosette 712. The rosette 712 is clocked relative to a reference rosette 718. By clocking the rosette 712 relative to the reference rosette 718, the dome layer 706 has an effective fiber angle of approximately 90 degrees. By laminating the dome layer 706 at zero fiber angle relative to the rosette 712, the dome layer 706 is laminated at an effective fiber angle of 90 degrees without the use of fiber steering.

[0084] The dome portion of the one-piece composite structure comprises multiple sets of dome layers stacked using multiple rosettes on the rounded end 714 of the mandrel 704. Dome layer 706 is one layer of the multiple sets of dome layers of the dome portion.

[0085] The cylindrical layer 708 is laminated with a lamination rosette independent of rosette 712. The cylindrical layer 708 is laminated with a lamination rosette independent of the rosettes for laminating the dome portion to the rounded end 714 of the mandrel 704. As shown in FIG. 700, the cylindrical layer 708 is laminated to the edge of the dome layer 706.

[0086] In some illustrative examples, after the cylindrical layer 708 is laminated, another cylindrical layer can be laminated over at least a portion of the cylindrical layer 708. The another cylindrical layer can have any desired fiber angle according to the design of the integrated composite structure. The another cylindrical layer is laminated using the same lamination rosette as the cylindrical layer 708.

[0087] In some exemplary embodiments, after the cylindrical layer 708 is laminated, another dome layer can be laminated on at least a portion of the cylindrical layer 708. In some exemplary embodiments, after the cylindrical layer 708 is laminated, another dome layer can be laminated against the cylindrical layer 708 or with a small gap to the cylindrical layer 708. The another dome layer can have any desired fiber angle according to the design of the one-piece composite structure. In some exemplary embodiments, the another dome layer can be laminated using rosette 712. In some exemplary embodiments, the another dome layer can be laminated using a rosette different from rosette 712.

[0088] A transition region can be formed between the dome and cylindrical portions formed by varying the length of the dome layers in the dome portion and varying the length of the cylindrical layers in the cylindrical portion. In some example embodiments, the next cylindrical layer stacked over a portion of the cylindrical layer 708 is shorter than the cylindrical layer 708 and does not cover as much of the rounded end 714 of the mandrel 704.

[0089] In some exemplary embodiments, the transition region comprises a double scarf joint formed by a pair of alternating cylindrical plies and dome plies. The transition region can include any desired number of joints. In some exemplary embodiments, the transition region comprises several joints that are staggered through a thickness of the one-piece composite structure.

[0090] 6 and 7, the one-piece composite structure is described as having multiple cylindrical layers forming a cylindrical portion, however, the composite structure may be layered with example embodiments having a non-cylindrical body. In some example embodiments, instead of a cylindrical portion, the composite structure may be one of a conical, elliptical, or other contoured portion.

[0091]

[0041] Referring now to Figure 8, a flow chart of a method for laminating a one-piece composite structure is shown in accordance with an exemplary embodiment. Method 800 may be performed to laminate one-piece 104 composite structure 102 of Figure 1. Method 800 may be performed to laminate one-piece composite structure 202 of Figure 2. Lamination of dome layer 302 of Figure 3 may occur during method 800. Lamination of dome layer 402 of Figure 4 may occur during method 800. Lamination of dome layer 502 of Figure 5 may occur during method 800. Method 800 may be performed to form laminate 601 of Figure 6. Method 800 may be performed to form laminate 701 of Figure 7.

[0092] The method 800 laminates a plurality of dome layers onto a rounded end of a mandrel using a plurality of rosettes (operation 802). The method 800 laminates a plurality of cylindrical layers onto a cylindrical surface of the mandrel using a lamination rosette independent of the plurality of rosettes (operation 804). The method 800 varies the lengths of the plurality of dome layers and the plurality of cylindrical layers to form a transition region with a junction between the plurality of dome layers and the plurality of cylindrical layers (operation 805). The method 800 then ends.

[0093] In some example embodiments, stacking the plurality of dome layers comprises stacking a plurality of sets of layers, where each set of layers of the plurality of sets of layers is stacked at a zero degree fiber angle according to a respective rosette of the plurality of rosettes (operation 806). By stacking each ply at a zero degree fiber angle relative to its respective rosette, each ply can be stacked at a desired effective fiber angle without an undesirable amount of fiber steering. Each set of layers comprises any desired number of plies.

[0094] In some example embodiments, laminating each dome layer of the plurality of dome layers comprises laminating a plurality of alternating paths, where each path of the plurality of alternating paths comprises a plurality of tows (operation 808). The plurality of tows comprises any desired quantity of tows.

[0095] In some exemplary embodiments, forming the transition region comprises forming a joint completely at the rounded end of the mandrel (operation 810). The lengths of the dome layers and the cylindrical layers can vary by any desired amount. In some exemplary embodiments, the lengths of the dome layers can vary by about 0.5 inches.

[0096] In some example embodiments, forming the transition region comprises alternating stacking of a plurality of dome layers and a plurality of cylindrical layers to form a joint (operation 812). Any desired number of dome layers may be stacked before stacking a cylindrical layer. Furthermore, the number of dome layers stacked before stacking a subsequent number of cylindrical layers is independent of other quantities of dome layers previously laid.

[0097] In some exemplary embodiments, the plurality of rosettes comprises at least four rosettes (operation 814). In some exemplary embodiments, the plurality of rosettes comprises six rosettes. In some exemplary embodiments, the plurality of rosettes comprises more than six rosettes.

[0098] In some illustrative examples, the method 800 includes curing the multiple dome layers and the multiple cylindrical layers on the mandrel (operation 816). The multiple dome layers and the multiple cylindrical layers are co-cured on the mandrel. Co-curing the multiple dome layers and the multiple cylindrical layers on the mandrel forms a one-piece composite structure having a dome portion, a cylindrical portion, and a transition area between the dome portion and the cylindrical portion. Co-curing the multiple dome layers and the multiple cylindrical layers on the mandrel forms a one-piece composite structure having a half-capsule shape.

[0099] In some illustrative examples, laying up the plurality of cylindrical layers includes rotating the mandrel during laying up of the plurality of cylindrical layers (operation 818). In some illustrative examples, rotating the mandrel can cause the composite laying head to stay on course.

[0100] In some demonstrative embodiments, the method 800 divides 180 degrees into equal increments to set clocking offsets for the plurality of rosettes (operation 820). In some demonstrative embodiments, each rosette is approximately equally offset from adjacent rosettes.

[0101]

[0046] Referring now to Figure 9, a flow chart of a method for laminating a composite structure is shown according to an exemplary embodiment. The method 900 can be performed to laminate the one-piece 104 composite structure 102 of Figure 1. The method 900 can be performed to laminate the one-piece composite structure 202 of Figure 2. The step of laminating the dome layer 302 of Figure 3 can be performed during the method 900. The step of laminating the dome layer 402 of Figure 4 can be performed during the method 900. The step of laminating the dome layer 502 of Figure 5 can be performed during the method 900. The method 900 can be performed to form the laminate 601 of Figure 6. The method 900 can be performed to form the laminate 701 of Figure 7.

[0102] In method 900, a plurality of dome layers are laminated to a rounded end of a mandrel (operation 902). In method 900, laminating the plurality of dome layers comprises laminating a first set of layers to the rounded end of the mandrel at a fiber angle of 0 degrees using a first rosette (operation 906). In method 900, laminating the plurality of dome layers comprises laminating a second set of layers to the rounded end of the mandrel at a fiber angle of 0 degrees using a second rosette offset from the first rosette (operation 908). In method 900, laminating the plurality of dome layers comprises laminating a third set of layers to the rounded end of the mandrel at a fiber angle of 0 degrees using a third rosette offset from both the first rosette and the second rosette (operation 910).

[0103] The method 900 includes stacking a plurality of cylindrical layers on a cylindrical surface of a mandrel that contacts the plurality of dome layers (operation 904). The method 900 includes varying the length of the plurality of dome layers and the plurality of cylindrical layers to form a joint between the plurality of dome layers and the plurality of cylindrical layers (operation 912). By varying the length of the plurality of dome layers and the plurality of cylindrical layers, any desired type of joint can be formed. The method 900 then ends.

[0104] In some illustrative embodiments, the bond is formed completely into the rounded end of the mandrel (operation 913).

[0105] In some example embodiments, stacking the plurality of cylindrical layers includes laying down alternating sets of cylindrical layers and sets of dome layers to form joints between the plurality of dome layers and the plurality of cylindrical layers (operation 914). The sets of cylindrical layers and the sets of dome layers are stacked congruently to form joints.

[0106] In some example embodiments, laminating each dome layer of the plurality of dome layers comprises laminating a plurality of alternating paths, where each path of the plurality of alternating paths comprises a plurality of tows (operation 916). Each of the plurality of alternating paths comprises the same plurality of tows. In some example embodiments, the plurality of tows comprises at least 16 tows.

[0107] As used herein, the phrase "at least one of," when used in conjunction 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. An item may be a particular object, thing, or category. In other words, "at least one of" means that any combination of items and number of items may be used from the list, but not all of the items in the list are required.

[0108] As used herein, "some" when used in reference to an item means one or more of the item.

[0109] 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 example embodiments. In this regard, each block in the flowcharts or block diagrams may represent at least one of a module, a segment, a function, or a portion of an operation or step.

[0110] In some alternative implementations of the exemplary embodiments, the function or functions noted in the blocks may occur out of the order noted in the figures. For example, in some cases, two blocks shown in succession may be executed substantially concurrently or in the reverse order, depending on the functionality involved. Also, other blocks may be added in addition to the illustrated blocks of a flowchart or block diagram. Some blocks may be optional. For example, operations 806-820 may be optional. As another example, operations 906-916 may be optional.

[0111] An example embodiment of the present disclosure may be described with reference to an aircraft manufacturing and service method 1000 as shown in Figure 10 and an aircraft 1100 as shown in Figure 11. With reference initially to Figure 10, an illustration of an aircraft manufacturing and service method is shown in block diagram form in accordance with an example embodiment. During pre-production, aircraft manufacturing and service method 1000 may include specification and design 1002 and material procurement 1004 of the aircraft 1100 in Figure 11.

[0112] During production, component and subassembly manufacturing 1006 and systems integration 1008 of the aircraft 1100 occurs. The aircraft 1100 may then undergo certification and delivery 1010 for in-service 1012. While in service 1012 by a customer, the aircraft 1100 is scheduled for routine maintenance and service 1014, which may include modification, reconfiguration, refurbishment, or other maintenance and service.

[0113] Each of the processes of aircraft manufacturing and service method 1000 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 subcontractors of major systems, a third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers, and an operator may be an airline, a leasing company, the military, a service provider, etc.

[0114] With reference now to Figure 11, an illustration of an aircraft in block diagram form is shown in which an illustrative embodiment may be implemented. In this example, aircraft 1100 may be produced by aircraft manufacturing and service method 1000 in Figure 10 and may include an airframe 1102 having a number of systems 1104 and an interior 1106. Example systems 1104 include one or more of a propulsion system 1108, an electrical system 1110, a hydraulic system 1112, and an environmental system 1114. Any number of other systems may also be included.

[0115] Apparatus and methods embodied herein may be used during at least one of the stages of aircraft manufacturing and service method 1000. One or more illustrative embodiments may be manufactured or used during at least one of component and subassembly manufacturing 1006, system integration 1008, in-service 1012, or maintenance and service 1014 of FIG.

[0116] Exemplary embodiments provide a fiber method of depositing an integrated dome / cylinder structure using hybrid rosettes. In some exemplary embodiments, one method is to cantilever a dome / cylinder tool. An exemplary embodiment for fibers deposits a dome cover layer with a 0 degree rosette perpendicular to the axis of symmetry. Each of the rosettes is rotated about a surface normal (axis of symmetry, or the Z-axis of the reference rosette) at the apex of the dome. An exemplary embodiment for fibers deposits a cylinder layer with a 0 degree rosette parallel to the axis of symmetry. An exemplary embodiment staggers the layer interfaces across the dome for matching effects. An exemplary embodiment co-cures the dome / cylinder structure.

[0117] In exemplary embodiments, the dome layers have separate rosette datums. In exemplary embodiments, the dome layers are "clocked" a desired amount. In some non-limiting exemplary embodiments, the dome layers are "clocked" in 22.5 degree increments (0, 22.5, 45, 67.5, 90, 112.5, 135, 157.5 degrees) to maintain a desired "angular gap" through thickness. In some exemplary embodiments, maintaining a desired angular gap comprises minimizing variation. The angular gap is the maximum angle between adjacent fiber directions through thickness. In some exemplary embodiments, the layer interfaces are separated by 0.5 inches. In other exemplary embodiments, the layer interfaces can be separated by more or less than 0.5 inches.

[0118] In some exemplary embodiments, the next successive interface is placed between the previous interface to distribute the interfaces through the thickness. Any desired number of effective fiber angles can be present in the dome portion. In some exemplary embodiments, the dome portion includes four orientations. In some exemplary embodiments, the dome portion includes six orientations. In some exemplary embodiments, the dome portion includes at least eight orientations (i.e., 22.5 degree increments) to reduce the angle gap. More angles provide more uniform properties.

[0119] Exemplary embodiments show a cylinder and a dome fabric laid together using two separate layup techniques. Exemplary embodiments utilize a cantilevered tool on a rotor. Exemplary embodiments include a dome and a cylinder laid simultaneously. In some exemplary embodiments, the cylinder is laid first. An automated placement system head rotates for the dome. The cylinder and dome have separate rosette datums. The dome layers are "clocked" in approximately equal increments. In some exemplary embodiments, the increments can be 0, 22.5, 45, 67.5, 90, 112.5, 135, 157.5. In some exemplary embodiments, the increments are selected to maintain a minimum "angular gap" through the thickness. The angular gap is equal to the difference in fiber angle between two adjacent fiber directions through the thickness.

[0120] The description of different exemplary embodiments has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments in the disclosed form. Many modifications and variations will be apparent to those skilled in the art. Furthermore, different exemplary embodiments may provide different features as compared to other exemplary embodiments. The selected embodiment or embodiments have been selected and described in order to best explain the principles, practical applications of the embodiments, 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]

[0121] 100 manufacturing environment, 102 composite structure, 104 one piece, 106 dome section, 108 dome layer, 109 multiple sets of layers, 110 multiple rosettes, 111 reference rosette, 112 cylindrical section, 114 stacked rosettes, 115 apex, 116 rounded end, 118 mandrel, 120 cylindrical surface, 122 multiple tows, 123 alternating paths, 124 composite tow placement head, 126 first rosette, 128 second rosette, 130 third rosette, 132 fourth rosette, 134 fifth rosette, 135 fiber angle gap, 136 sixth rosette, 137 length, 138 first set of layers, 139 apex, 140 second set of layers, 142 third set of plies, 144 fourth set of plies, 146 fifth set of plies, 148 sixth set of plies, 150 effective first fiber angle, 152 effective second fiber angle, 154 effective third fiber angle, 156 effective fourth fiber angle, 158 effective fifth fiber angle, 160 effective sixth fiber angle, 164 rosette, 166 clocking offset, 168 multiple cylindrical plies, 170 first set of cylindrical plies, 171 fiber angle, 172 second set of cylindrical plies, 173 fiber angle, 174 third set of cylindrical plies, 175 fiber angle, 176 fourth set of cylindrical plies, 177 fiber angle, 178 fifth set of cylindrical plies, 179 fiber angle, 180 sixth set of cylindrical plies, 181 fiber angle, 182 length, 184 transition area, 186 junction, 188 scarf junction, 190 half capsule, 191 cap, 192 composite pressure hull, 193 junction, 194 one-piece first half, 195 body, 196 one-piece second half, 198 ring, 200 diagram, 202 one-piece composite structure, 204 dome section, 206 cylindrical section, 208 transition area, 210 mandrel, 212 rounded end, 214 cylindrical surface, 216 multiple dome layers, 218 multiple cylindrical layers, 300 diagram, 302 dome layer, 304 alternating paths, 306 multiple tows, 308 rosette, 400 diagram, 402 dome layer, 404 alternating paths, 406 multiple tows, 408 rosette, 500 diagram, 502 dome layer, 504 Alternating paths, 506 Multiple tows, 508 Rosette, 600 Diagram, 601 Lamination, 602 Multiple layers, 604 Mandrel, 606 Dome layer, 608 Cylindrical layer, 610 Transition region, 612rosette, 614 rounded end, 616 cylindrical surface, 618 reference rosette, 700 diagram, 701 stack, 702 multiple layers, 704 mandrel, 706 dome layer, 708 cylindrical layer, 710 transition region, 712 rosette, 714 rounded end, 716 cylindrical surface, 718 reference rosette, 800 method, 802 operation, 804 operation, 805 operation, 806 operation, 808 operation, 810 operation, 812 operation, 814 operation, 816 operation, 818 operation, 820 operation, 900 method, 902 operation, 904 operation, 906 operation, 908 operation, 910 operation, 912 operation, 913 operation, 914 operation, 916 Operation, 1000 Maintenance methods, 1002 Specification and design, 1004 Material procurement, 1006 Component and subassembly manufacturing, 1008 System integration, 1010 Certification and delivery, 1012 In-service, 1014 Maintenance and overhaul, 1100 Aircraft, 1102 Airframe, 1104 Systems, 1106 Interior, 1108 Propulsion system, 1110 Electrical system, 1112 Hydraulic system, 1114 Environmental system

Claims

1. A method (800) for laminating a one-piece (104) composite structure (102, 202), comprising: laminating (802) a plurality of dome layers (108, 216) to a rounded end (116, 212) of a mandrel (118, 210) using a plurality of rosettes (110, 308, 408, 508); laminating (804) a plurality of cylindrical layers (168, 218) on a cylindrical surface (120, 214) of the mandrel (118, 210) using a lamination rosette (114) separate from the plurality of rosettes (110, 308, 408, 508); varying a length (137) of the plurality of dome layers (108, 216) and a length (182) of the plurality of cylindrical layers (168, 218) to form a transition region (184, 208) comprising a junction (186) between the plurality of dome layers (108, 216) and the plurality of cylindrical layers (168, 218); A method (800) comprising:

2. 2. The method (800) of claim 1, wherein stacking the plurality of dome layers (108, 216) comprises stacking (806) a plurality of sets of layers (109), wherein each set of layers (138, 140, 142, 144, 146, 148) of the plurality of sets of layers (109) is stacked at a 0 degree fiber angle according to a respective rosette (126, 128, 130, 132, 134, 136) of the plurality of rosettes (110, 308, 408, 508).

3. 2. The method (800) of claim 1, wherein stacking each dome layer of the plurality of dome layers (108, 216) comprises stacking (808) a plurality of alternating paths (123, 304, 404, 504), wherein each path of the plurality of alternating paths (123, 304, 404, 504) comprises a plurality of tows (122, 306, 406, 506).

4. 2. The method (800) of claim 1, wherein forming the transition region (184, 208) comprises forming (810) the junction (186) completely at the rounded end (116, 212) of the mandrel (118, 210).

5. 2. The method (800) of claim 1, wherein forming the transition region (184, 208) comprises stacking (812) the plurality of dome layers (108, 216) and the plurality of cylindrical layers (168, 218) in an alternating manner to form the junction (186).

6. 2. The method (800) of claim 1, wherein the plurality of rosettes (110, 308, 408, 508) comprises (814) at least four rosettes (164, 126, 128, 130, 132).

7. curing (816) the plurality of dome layers (108, 216) and the plurality of cylindrical layers (168, 218) of the mandrel (118, 210); The method (800) of claim 1, further comprising:

8. Dividing (820) 180 degrees into equal increments to set clocking offsets (166) for said plurality of rosettes (110, 308, 408, 508). The method (800) of claim 1, further comprising:

9. 2. The method (800) of claim 1, wherein the step of laying up the plurality of cylindrical layers (168, 218) comprises the step of rotating (818) the mandrel (118, 210) during laying up the plurality of cylindrical layers (168, 218).

10. a dome portion (106, 204) having a plurality of sets of layers (109) stacked using a plurality of rosettes (110, 308, 408, 508); a cylindrical portion (112, 206) stacked with a stacked rosette (114) independent of the plurality of rosettes (110, 308, 408, 508); a transition region (184, 208) between the dome portion (106, 204) and the cylindrical portion (112, 206) formed by varying a length (137) of a plurality of dome layers (108, 216) of the dome portion (106, 204) and by varying a length (182) of a plurality of cylindrical layers (168, 218) of the cylindrical portion (112, 206); A one-piece (104) composite structure (102, 202) comprising:

11. 11. The one-piece (104) composite structure (102, 202) of claim 10, wherein the one-piece (104) composite structure (102, 202) has a semi-capsule shape comprising a cap (191) and a body (195) joined by a joint (193), wherein the cap (191) comprises the dome portion (106, 204), the transition region (184, 208), and an edge of the cylindrical portion (112, 206), wherein the body (195) is formed by the cylindrical portion (112, 206).

12. 11. The one-piece (104) composite structure (102, 202) of claim 10, wherein the transition region (184, 208) comprises a double scarf joint formed by alternating pairs of cylindrical layers (170, 172, 174, 176, 178, 180) and pairs of dome layers (138, 140, 142, 144, 146, 148).

13. 11. The one-piece (104) composite structure (102, 202) of claim 10, wherein the dome portion (106, 204) comprises a number of fiber angles (150, 152, 154, 156, 158, 160) equal to a number of rosettes (164) in the plurality of rosettes (110, 308, 408, 508).

14. 11. The one-piece (104) composite structure (102, 202) of claim 10, wherein fiber angles (150, 152, 154, 156, 158, 160) of the dome portions (106, 204) are offset from one another approximately equally.

15. The one-piece (104) composite structure (102, 202) of claim 10, wherein the plurality of rosettes (110, 308, 408, 508) comprises at least four rosettes.

16. 11. The one-piece (104) composite structure (102, 202) of claim 10, wherein the fiber angle gap (135) of the dome portion (106, 204) is less than 45 degrees.

17. A method (900) for laminating a composite structure (102, 202), comprising the steps of: A step (902) of laminating a plurality of dome layers (108, 216) onto a rounded end (116, 212) of a mandrel (118, 210), comprising: laying (906) a first set of plies (138, 302) onto the rounded end (116, 212) of the mandrel (118, 210) using a first rosette (126, 308) at a fiber angle of 0 degrees; laying (908) a second set of plies (140, 402) on the rounded end (116, 212) of the mandrel (118, 210) at a zero degree fiber angle using a second rosette (128, 408) offset from the first rosette (126, 308); laying (910) a third set of plies (142, 502) on the rounded end (116, 212) of the mandrel (118, 210) at a zero degree fiber angle using a third rosette (130, 508) offset from both the first rosette (126, 308) and the second rosette (128, 408); A laminating step (902) comprising: laminating (902) a plurality of cylindrical layers (168, 218) on a cylindrical surface (120, 214) of the mandrel (118, 210) that contacts the plurality of dome layers (108, 216); Varying (912) lengths (182, 137) of the plurality of dome layers (108, 216) and the plurality of cylindrical layers (168, 218) to form joints (186) between the plurality of dome layers (108, 216) and the plurality of cylindrical layers (168, 218); A method (900) comprising:

18. The method (900) of claim 17, wherein the joint (186) is integrally formed into the rounded end (116, 212) of the mandrel (118, 210).

19. 20. The method (900) of claim 17, wherein stacking the plurality of cylindrical layers (168, 218) comprises laying (914) alternating sets of cylindrical layers (170, 172, 174, 176, 178, 180) and sets of dome layers (138, 140, 142, 144, 146, 148) to form joints (186) between the plurality of dome layers (108, 216) and the plurality of cylindrical layers (168, 218).

20. 20. The method (900) of claim 17, wherein stacking each dome layer of the plurality of dome layers (108, 216) comprises stacking (916) a plurality of alternating paths (123, 304, 404, 504), wherein each path of the plurality of alternating paths (123, 304, 404, 504) comprises a plurality of tows (122, 306, 406, 506).

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