Integral composite structure

Abstract

The invention relates to a monolithic composite structure. A monolithic composite structure and method of formation are presented. A method of laying a monolithic composite structure includes laying a plurality of circular top sheets on a circular end of a mandrel using a plurality of guide sheets; laying a plurality of cylindrical plies on the cylindrical surface of the mandrel using a laminated guide vane independent of the plurality of guide vanes; and forming a transition region by varying the length of the plurality of round top plies and the length of the plurality of cylindrical plies, the transition region including a joint between the plurality of round top plies and the plurality of cylindrical plies.

Description

Technical Field

[0001] The present disclosure relates generally to composite material manufacturing and, more particularly, to the formation of a composite structure including a dome portion and a cylindrical portion. Background Art

[0002] Weight reduction is a matter of storing, manufacturing or transporting different 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 for laying up a monolithic composite structure. A plurality of dome-shaped plies are laid on the circular end of a mandrel using a plurality of rosettes. A plurality of cylindrical plies are laid on the cylindrical surface of the mandrel using a stacking guide independent of the plurality of rosettes. A transition region is formed, the transition region including a joint between the plurality of dome-shaped plies and the plurality of cylindrical plies by changing the length of the plurality of dome-shaped plies and the length of the plurality of cylindrical plies.

[0006] Another embodiment of the present disclosure provides a monolithic composite structure. The monolithic composite structure includes: a dome portion, the dome portion including a plurality of groups of plies laid using a plurality of guides; a cylindrical portion, the cylindrical portion being laid with a stacked guide independent of the plurality of guides; and a transition region between the dome portion and the cylindrical portion, the transition region being formed by changing the length of the plurality of dome plies of the dome portion and changing the length of the plurality of cylindrical plies of the cylindrical portion.

[0007] Another embodiment of the present disclosure provides a method for laying up a composite structure. A plurality of dome-shaped plies are laid up on a circular end of a mandrel. Laying up the plurality of dome-shaped plies includes: laying down a first group of plies on the circular end of the mandrel at a zero-degree fiber angle using a first guide vane; laying down a second group of plies on the circular end of the mandrel at a zero-degree fiber angle using a second guide vane offset from the first guide vane; and laying down a third group of plies on the circular end of the mandrel at a zero-degree fiber angle using a third guide vane offset from both the first guide vane and the second guide vane. A plurality of cylindrical plies are laid up on a cylindrical surface of the mandrel to contact the plurality of dome-shaped plies. The lengths of the plurality of dome-shaped plies and the plurality of cylindrical plies are varied to form joints between the plurality of dome-shaped plies and the plurality of cylindrical plies.

[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 monolithic composite structure on a mandrel according to an illustrative embodiment;

[0012] Figure 3 is an illustration of a front view of a ply of a dome portion of a composite structure according to an illustrative embodiment;

[0013] Figure 4 is an illustration of a front view of a ply of a dome portion of a composite structure according to an illustrative embodiment;

[0014] Figure 5 is an illustration of a front view of a ply of a dome portion of a composite structure according to an illustrative embodiment;

[0015] Figure 6 is an illustration of an isometric view of a composite ply laid up on a mandrel according to an illustrative embodiment;

[0016] Figure 7 is an illustration of an isometric view of a composite ply laid up on a mandrel according to an illustrative embodiment;

[0017] Figure 8is a flow chart of a method of laying up a monolithic composite structure according to an illustrative embodiment;

[0018] Fig. 9 is a flow chart of a method of laying up a composite structure according to an illustrative embodiment;

[0019] Fig.10 is an illustration of an aircraft manufacturing and service methodology in block diagram form in accordance with an illustrative embodiment; and

[0020] Fig.11 is an illustration of an aircraft in block diagram form in which illustrative embodiments may be implemented. DETAILED DESCRIPTION

[0021] The illustrative examples take into account one or more considerations. The illustrative examples take into account that current dome manufacturing uses standard guide vane orientation methods, and the dome and cylinder are manufactured separately. The illustrative examples recognize and take into account that large domes allow cylindrical (standard orientation) plies to be turned onto the dome area. The illustrative examples recognize and take into account that the turning radius using standard guide vane orientation methods on smaller dome structures becomes small enough to produce undesirable effects in the dome. The illustrative examples also recognize and take into account that conventional fiber placement paths that transition onto the dome surface have singularities at the poles of the dome, resulting in unacceptable results. The illustrative examples provide methods of forming and monolithic composite structures that can be formed to have smaller dome diameters without undesirable effects. The illustrative examples provide methods and monolithic composite structures that are formed without singularities at the poles. The illustrative examples provide methods of forming a monolithic composite structure having a cabin shape.

[0022] Now turn to Figure 1 , an illustration of a block diagram of a manufacturing environment is depicted in accordance with an illustrative embodiment. Monolithic 104 composite structure 102 is manufactured in manufacturing environment 100. Monolithic 104 composite structure 102 includes dome portion 106 including a plurality of groups of plies 109 laid up using a plurality of guide vanes 110 and cylindrical portion 112 laid up using layup guide vanes 114 that are independent of plurality of guide vanes 110. In some illustrative examples, layup guide vanes 114 are projected onto a surface such that a y-axis extends longitudinally along mandrel 118 and an x-axis extends in a circumferential direction.

[0023] The stacking guide 114 for the cylindrical portion 112 includes an axis in a reference coordinate system. In some illustrative examples, the X axis can be used for the zero reference. Any axis of the stacking guide 114 can be used for the zero reference. The axis can be anywhere in space. In some illustrative examples, the axis is the axis of symmetry of the mandrel 118.

[0024] In some illustrative examples, a reference axis is projected onto cylindrical surface 120 at a point to define a 0 direction on cylindrical surface 120. The fiber angle is then rotated from the 0 projection about the surface normal about the local point to determine the path direction at that point.

[0025] The monolithic 104 composite structure 102 is laid up on a mandrel 118. The mandrel 118 includes a circular end 116 and a cylindrical surface 120. The domed portion 106 is laid up on the circular end 116 of the mandrel 118. The cylindrical portion 112 is laid up on the cylindrical surface 120.

[0026] The dome portion 106 includes a plurality of dome plies 108 laid up on a circular end 116 of a mandrel 118. The plurality of dome plies 108 are laid up completely on the circular end 116 of the mandrel 118. The cylindrical portion 112 includes a plurality of cylindrical plies 168 laid up on a cylindrical surface 120. At least one cylindrical ply of the plurality of cylindrical plies 168 extends onto the circular end 116 of the mandrel 118. The portion of the plurality of cylindrical plies 168 that extends onto the circular end 116 forms a transition region 184.

[0027] In some illustrative examples, a cylindrical ply in plurality of cylindrical plies 168 is a composite ply that generally begins on cylindrical surface 120 and transitions to a portion of circular end 116 of mandrel 118. In some illustrative examples, many of plurality of cylindrical plies 168 will continue onto circular end 116 of mandrel 118. In some illustrative examples, all of plurality of cylindrical plies 168 will continue onto circular end 116 of mandrel 118. The material properties of plurality of dome plies 108 may be undesirable at the edge of circular end 116 where circular end 116 intersects cylindrical surface 120. Therefore, plurality of dome plies 108 may be laid up on circular end 116 and terminate prior to intersecting cylindrical surface 120.

[0028] In some illustrative examples, each guide vane in plurality of guide vanes 110 has a Z-axis extending into apex 115 of rounded end 116 of mandrel 118. In some illustrative examples, each guide vane in plurality of guide vanes 110 has a Z-axis extending parallel to cylindrical surface 120 of mandrel 118. In some illustrative examples, each guide vane in plurality of guide vanes 110 has a Z-axis perpendicular to plurality of dome-shaped top sheets 108 above apex 115 of rounded end 116 of mandrel 118.

[0029] Plurality of guides 110 includes guides that rotate about a z-axis that extends toward or away from vertex 115. In some illustrative examples, the rotation about the z-axis may be referred to as “clocking.” In some illustrative examples, plurality of guides 110 includes a reference guide 111 and a plurality of guides that are clocked about the z-axis relative to the reference guide. In some illustrative examples, the reference guide is positioned to lay zero-degree fiber angle plies in composite structure 102.

[0030] In some illustrative examples, the reference guide 111 is oriented such that the Z axis is perpendicular to the vertex 115 of the circular portion 116 of the mandrel 118. In some illustrative examples, the reference guide 111 is oriented such that the Z axis is parallel to the longitudinal axis of the cylindrical surface 120 of the mandrel 118. The x-axis and y-axis of the reference guide 111 can have any desired orientation. In some illustrative examples, the reference guide 111 is oriented such that one axis is parallel to the Z axis of the lamination guide 114. In some illustrative examples, the reference guide has a Y axis that is perpendicular to the manufacturing floor. In some illustrative examples, the reference guide has an X axis that is parallel to the manufacturing floor.

[0031] The guide vanes are used to orient the plurality of tows 122 for placement by the composite tow placement head 124. Prior to placing the plurality of tows 122 on the mandrel 118, the composite tow placement head 124 positions itself relative to the mandrel 118 using corresponding guide vanes of the plurality of guide vanes 110.

[0032] The plurality of guides 110 may include any desired number 164 of guides. In some illustrative examples, the plurality of guides 110 includes at least four guides. As shown, the plurality of guides 110 includes six guides, namely a first guide 126, a second guide 128, a third guide 130, a fourth guide 132, a fifth guide 134, and a sixth guide 136. In some illustrative examples, the plurality of guides 110 includes more than six guides. In some illustrative examples, the dome portion 106 includes a number of fiber angles equal to the number 164 of guides in the plurality of guides 110.

[0033] In some illustrative examples, the spacing between each of the plurality of guides 110 is determined by dividing one hundred eighty degrees into equal increments to set the timing offset 166 of the plurality of guides 110. In one illustrative example, when the certain number 164 of guides includes four guides, the timing offset 166 is 180 / 4 or 45 degrees. In this illustrative example, the plurality of guides 110 includes 0 degrees, 45 degrees, 90 degrees, and 135 degrees. In one illustrative example, when the certain number 164 of guides is six guides, the timing offset 166 is 180 / 6 or 30 degrees. In this illustrative example, the plurality of guides 110 includes 0 degrees, 30 degrees, 60 degrees, 90 degrees, 120 degrees, and 150 degrees. In another illustrative example, when the certain number 164 of guides is eight guides, the timing offset 166 is 180 / 8 or 22.5 degrees. In this illustrative example, plurality of guide vanes 110 includes 0 degrees, 22.5 degrees, 45 degrees, 67.5 degrees, 90 degrees, 112.5 degrees, 135 degrees, and 157.5 degrees.

[0034] The dome portion 106 includes a plurality of dome top sheets 108. The plurality of dome top sheets includes a plurality of groups of plies 109.

[0035] The plurality of groups of plies 109 include a first group of plies 138, a second group of plies 140, a third group of plies 142, a fourth group of plies 144, a fifth group of plies 146, and a sixth group of plies 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 group of plies 138, the second group of plies 140, the third group of plies 142, the fourth group of plies 144, the fifth group of plies 146, and the sixth group of plies 148 can be laid in any desired order. In addition, each group of the first group of plies 138, the second group of plies 140, the third group of plies 142, the fourth group of plies 144, the fifth group of plies 146, and the sixth group of plies 148 can have any desired number of plies per group. Although the plurality of dome top sheets 108 is shown as including first, second, third, fourth, fifth, and sixth groups of plies 138, 140, 142, 144, 146, and 148, any desired number of groups of plies may be included in the plurality of dome top sheets 108.

[0036] In some illustrative examples, each dome top sheet in plurality of dome top sheets 108 includes plurality of alternating paths 123 of plurality of tows 122. Each path in plurality of alternating paths 123 includes plurality of tows 122. In some illustrative examples, plurality of tows 122 includes sixteen tows. Plurality of tows 122 includes any desired number of tows.

[0037] Each corresponding set of dome plies is laid up using a corresponding guide sheet from the plurality of guide sheets 110. A first set of plies 138 is laid up using a first guide sheet 126. The first set of plies 138 is laid up at a zero degree fiber angle relative to the first guide sheet 126. The first guide sheet 126 is any desired guide sheet from the plurality of guide sheets 110. By laying up the first set of plies 138 according to the first guide sheet 126, the first set of plies 138 has an effective first fiber angle 150. The first set of plies 138 has an effective first fiber angle 150 relative to a reference guide sheet 111. In some illustrative examples, the first guide sheet 126 is the same as the reference guide sheet 111. In some illustrative examples, when the first guide sheet 126 is the same as the reference guide sheet 111, the effective first fiber angle 150 is zero degrees. In some illustrative examples, when the first guide sheet 126 is a guide sheet different from the reference guide sheet 111, the effective first fiber angle 150 is an angle different from zero degrees.

[0038] The second set of plies 140 is laid up using the second guide 128. The second set of plies 140 is laid up at zero degrees relative to the second guide 128. By laying up the second set of plies 140 according to the second guide 128, the second set of plies 140 has an effective second fiber angle 152. In some illustrative examples, the second guide 128 is timed relative to the reference guide 111. When the second guide 128 is timed relative to the reference guide 111, the effective second fiber angle 152 is a non-zero fiber angle relative to the reference guide 111. As depicted, the number of guides 164 is six, and the effective second fiber angle 152 can be one of 30 degrees, 60 degrees, 90 degrees, 120 degrees, or 150 degrees. In some illustrative examples, the effective second fiber angle 152 is 30 degrees.

[0039] The third group of plies 142 is laid using the third guide 130. The third group of plies 142 is laid at zero degrees relative to the third guide 130. By laying the third group of plies 142 according to the third guide 130, the third group of plies 142 has an effective third fiber angle 154. In some illustrative examples, the third guide 130 is timed relative to the reference guide 111. When the third guide 130 is timed relative to the reference guide 111, the effective third fiber angle 154 is a non-zero fiber angle relative to the reference guide 111. As shown, the number 164 of guides is six, and the effective third fiber angle 154 can be one of 30 degrees, 60 degrees, 90 degrees, 120 degrees, or 150 degrees. In some illustrative examples, the effective third fiber angle 154 is 60 degrees. In some illustrative examples, the fiber angles of the dome portion 106 are offset approximately equally from each other.

[0040] A fourth set of plies 144 is laid up using a fourth guide 132. The fourth set of plies 144 is laid up at zero degrees relative to the fourth guide 132. By laying up the fourth set of plies 144 according to the fourth guide 132, the fourth set of plies 144 has an effective fourth fiber angle 156. In some illustrative examples, the fourth guide 132 is timed relative to a reference guide 111. When the fourth guide 132 is timed relative to the reference guide 111, the effective fourth fiber angle 156 is a non-zero fiber angle relative to the reference guide 111. As depicted, the number of guides 164 is six, and the effective fourth fiber angle 156 can be one of 30 degrees, 60 degrees, 90 degrees, 120 degrees, or 150 degrees. In some illustrative examples, the effective fourth fiber angle 156 is 90 degrees.

[0041] The fifth group of plies 146 is laid using the fifth guide 134. The fifth group of plies 146 is laid at zero degrees relative to the fifth guide 134. By laying the fifth group of plies 146 according to the fifth guide 134, the fifth group of plies 146 has an effective fifth fiber angle 158. In some illustrative examples, the fifth guide 134 is timed relative to the reference guide 111. When the fifth guide 134 is timed relative to the reference guide 111, the effective fifth fiber angle 158 is a non-zero fiber angle relative to the reference guide 111. As depicted, the number of guides 164 is six, and the effective fifth fiber angle 158 can be one of 30 degrees, 60 degrees, 90 degrees, 120 degrees, or 150 degrees. In some illustrative examples, the effective fifth fiber angle 158 is 120 degrees.

[0042] The sixth group of plies 148 is laid using the sixth guide 136. The sixth group of plies 148 is laid at zero degrees relative to the sixth guide 136. By laying the sixth group of plies 148 according to the sixth guide 136, the sixth group of plies 148 has an effective sixth fiber angle 160. In some illustrative examples, the sixth guide 136 is timed relative to the reference guide 111. When the sixth guide 136 is timed relative to the reference guide 111, the effective sixth fiber angle 160 is a non-zero fiber angle relative to the reference guide 111. As depicted, the number of guides 164 is six, and the effective sixth fiber angle 160 can be one of 30 degrees, 60 degrees, 90 degrees, 120 degrees, or 150 degrees. In some illustrative examples, the effective sixth fiber angle 160 is 150 degrees.

[0043] Each of the effective first fiber angle 150, the effective second fiber angle 152, the effective third fiber angle 154, the effective fourth fiber angle 156, the effective fifth fiber angle 158, and the effective sixth fiber angle 160 is laid using a corresponding guide. Due to the use of corresponding guides, steering is reduced or eliminated when laying the dome portion 106. Each of the effective first fiber angle 150, the effective second fiber angle 152, the effective third fiber angle 154, the effective fourth fiber angle 156, the effective fifth fiber angle 158, and the effective sixth fiber angle 160 is laid without steering the fiber. The steering in the dome portion 106 can cause one edge of the tow to be shorter or longer than another edge of the tow. By reducing or eliminating steering, inconsistencies such as wrinkling, wrinkling, or fiber lifting in the dome portion 106 are also reduced or eliminated.

[0044] In some illustrative examples, plurality of dome top sheets 108 are laid up so that a substantially equal number of plies are laid up at each effective fiber angle. In some illustrative examples, plurality of dome top sheets 108 are laid up so that a substantially equal number of plies are laid up with each guide vane in plurality of guide vanes 110.

[0045] Cylindrical portion 112 is laid up using layup guide 114. Lamination guide 114 is independent of plurality of guides 110. Each of plurality of cylindrical plies 168 of cylindrical portion 112 is laid up using lamination guide 114. Fiber steering may be performed to lay up a plurality of different fiber angles of cylindrical portion 112 using lamination guide 114. In some illustrative examples, fiber steering occurs in a layup section of cylindrical portion 112 having a non-zero ply angle that extends onto circular end 116 of mandrel 118.

[0046] First set of cylindrical plies 170 are laid up according to layup guide 114 to have fiber angle 171. Fiber angle 171 may have any desired fiber angle for designing composite structure 102. In some illustrative examples, fiber angle 171 is selected from zero degrees, 45 degrees, and 90 degrees.

[0047] Second set of cylindrical plies 172 are laid up according to layup guide 114 to have fiber angle 173. Fiber angle 173 may be any desired fiber angle for designing 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 than fiber angle 171.

[0048] A third set of cylindrical plies 174 are laid down at fiber angle 175 according to stacking guide 114. A fourth set of cylindrical plies 176 are laid down at fiber angle 177 according to stacking guide 114. A fifth set of cylindrical plies 178 are laid down at fiber angle 179 according to stacking guide 114. A sixth set of cylindrical plies 180 are laid down at fiber angle 181 according to stacking guide 114.

[0049] In some illustrative examples, plurality of cylindrical plies 168 are laid down such that each cylindrical ply overlaps a previous cylindrical ply.In some illustrative examples, first set of cylindrical plies 170 are laid down to cover the edges of first set of plies 138 .

[0050] Monolithic 104 composite structure 102 also includes a transition region 184 between dome portion 106 and cylindrical portion 112, transition region 184 formed by varying lengths 137 of plurality of dome plies 108 of dome portion 106 and by varying lengths 182 of plurality of cylindrical plies 168 of cylindrical portion 112. In some illustrative examples, varying lengths 137 of plurality of dome plies 108 of dome portion 106 and varying lengths 182 of plurality of cylindrical plies 168 of cylindrical portion 112 form joints 186 within transition region 184. In some illustrative examples, transition region 184 includes joints 186. In some illustrative examples, joints 186 take the form of scarf joints 188.

[0051] The transition region 184 is laid on the circular end 116 of the mandrel 118. The transition region 184 may be located in any desired portion on the circular end 116.

[0052] Dome portion 106 of monolithic 104 composite structure 102 does not have a central hole at apex 139 of dome portion 106. In some illustrative examples, for a positioning system where the X-axis (0 degrees) extends through apex 139 and is parallel to body 195 and the Y-axis (90 degrees) extends through joint 193, transition region 184 may be positioned within a range of 45 to 75 degrees. In some illustrative examples, transition region 184 is positioned within a range of 60 to 75 degrees. In some illustrative examples, transition region 184 is positioned to control fiber angle gap 135. In some illustrative examples, transition region 184 is positioned to maintain fiber angle gap 135 at or below 45 degrees.

[0053] In some illustrative examples, transition region 184 includes a double scarf joint formed by alternately laying up multiple groups of cylindrical plies and multiple groups of dome plies. In some illustrative examples, transition region 184 includes a double scarf joint formed by alternately laying up multiple groups of dome plies (such as first group of plies 138, second group of plies 140, or other desired groups of multiple dome plies 108) and multiple groups of cylindrical plies (such as first group of cylindrical plies 170, second group of cylindrical plies 172, or other desired groups of multiple cylindrical plies 168).

[0054] In some illustrative examples, joint 186 is formed by a series of adjacent plies of plurality of dome top sheets 108 and plies of plurality of cylindrical plies 168. In some illustrative examples, joint 186 includes slightly spaced plies of plurality of dome top sheets 108 and plies of plurality of cylindrical plies 168.

[0055] In some illustrative examples, transition region 184 has a series of joints between plies of the same thickness. In these illustrative examples, transition region 184 also includes at least one additional joint in addition to joint 186. In some illustrative examples, transition region 184 includes a set of joints (including joint 186) that are staggered through the thickness of monolithic 104 composite structure 102 and separated to minimize duplication at any location within transition region 184.

[0056] Composite structure 102 is cured after laying up cylindrical portion 112, dome portion 106, and transition region 184 formed by dome portion 106 and cylindrical portion 112. Dome portion 106 and cylindrical portion 112 are co-cured. In some illustrative examples, composite structure 102 may be described as having the shape of cabin 190.

[0057] Capsule 190 includes body 195 and cap 191 with joint 193 between body 195 and cap 191. In some illustrative examples, joint 193 is the location of the change in curvature. In some illustrative examples, body 195 is formed entirely of cylindrical portion 112. In some illustrative examples, cap 191 includes transition region 184. In some illustrative examples, cap 191 includes dome portion 106, transition region 184, and a portion of cylindrical portion 112.

[0058] Composite structure 102 may be part of composite pressure shell 192. In some illustrative examples, composite structure 102 may take the form of one of integral first half 194 or integral second half 196 of composite pressure shell 192. Composite pressure shell 192 includes integral first half 194 and integral second half 196 connected by ring 198.

[0059] Fiber angle gap 135 is a measure of how the fibers are spread out at a certain location. Fiber angle gap 135 has a maximum value close to 180 degrees. Fiber angle gap 135 is a measure of the fiber angle through the thickness. In some illustrative examples, fiber angle gap 135 is the maximum angle between the fiber angles at any location on the surface. Undesirably large fiber angle gaps undesirably affect the strength of composite structure 102. In some illustrative examples, it is desirable to reduce fiber angle gap 135 through the design of composite structure 102. In some illustrative examples, fiber angle gap 135 increases moving from apex 115 toward the connection between rounded end 116 and cylindrical surface 120.

[0060] Fiber angle gap 135 can be managed by the layup order of plurality of dome top sheets 108, the size of plurality of dome top sheets 108, and the number of guide vanes 164. Laying up plurality of dome top sheets 108 with shorter dome top sheets can reduce fiber angle gap 135. It can also be selected which of plurality of cylindrical plies 168 extend further over circular end 116 of mandrel 118 to reduce fiber angle gap 135. It can also be selected which specific fiber angles of cylindrical portion 112 extend further over circular end 116 of mandrel 118 to reduce fiber angle gap 135. Laying up plurality of dome top sheets 108 using plurality of guide vanes 110 with a greater number 164 of guide vanes can reduce fiber angle gap 135. In some illustrative examples, timing offset 166 is selected to reduce fiber angle gap 135. In some illustrative examples, the fiber angles of plurality of dome top sheets 108 and the desired structural conditions of composite structure 102 affect length 137 of plurality of dome top sheets 108. In some illustrative examples, fiber angle gap 135 of dome portion 106 is desirably equal to or less than 45 degrees. In some illustrative examples, to reduce fiber angle gap 135, number of guide vanes 164 may be increased. In some illustrative examples, to reduce fiber angle gap 135, some of plurality of cylindrical plies 168 may extend further onto circular end 116 of mandrel 118.

[0061] 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.

[0062] For example, in some illustrative examples, more than six groups of plies are present in number of dome top sheets 108. Number of dome top sheets 108 includes any desired number of plies divided into any desired number of groups.

[0063] Additionally, although composite structure 102 is described as having the shape of multiple cylindrical plies 168 and half-nacelles 190, composite structure 102 may have other desired shapes. In some illustrative examples, a non-cylindrical portion may be connected to dome portion 106 via transition region 184. In some illustrative examples, there is one of a conical, elliptical, or other contoured portion in place of cylindrical portion 112. In other words, mandrel 118 may have another shape besides cylindrical surface 120 while still having rounded end 116. In these illustrative examples, mandrel 118 may be used to form composite structure 102 where the body has a shape besides cylindrical.

[0064] Additionally, for some non-cylindrical shapes, transition region 184 may be located at least partially in the body of the composite structure. In these illustrative examples, transition region 184 may be located in any desired portion on rounded end 116 or the body of the mandrel, depending on the turns, angular clearances, angular deviations, and other characteristics from the design of the composite structure.

[0065] Now turn to Figure 2 , depicts an isometric view of a monolithic composite structure on a mandrel according to an illustrative embodiment. Monolithic composite structure 202 is depicted in view 200. Monolithic composite structure 202 is Figure 1 A physical realization of the monolithic 104 composite structure 102 .

[0066] The monolithic composite structure 202 includes a dome portion 204 and a cylindrical portion 206. The dome portion 204 includes a plurality of plies laid up using a plurality of guides. The cylindrical portion 206 is laid up using a stack guide that is independent of the plurality of guides.

[0067] Monolithic composite structure 202 also includes a transition region 208 between dome portion 204 and cylindrical portion 206, which is formed by varying the length of a plurality of dome plies 216 of dome portion 204 and varying the length of a plurality of cylindrical plies 218 transitioning to the cylindrical portion of dome portion 204. In some illustrative examples, transition region 208 includes a double scarf joint formed by alternatingly laid sets of cylindrical plies and sets of dome plies.

[0068] In some illustrative examples, dome portion 204 includes a number of fiber angles that is equal to the number of guides in the plurality of guides. In some illustrative examples, the fiber angles of dome portion 204 are offset approximately equally from one another. In some illustrative examples, the plurality of guides includes at least four guides. In some illustrative examples, the fiber angle gap of dome portion 204 is desirably equal to or less than 45 degrees.

[0069] The dome portion 204 is laid up on a circular end 212 of the mandrel 210. The cylindrical portion 206 is laid up on a cylindrical surface 214 of the mandrel 210. Some of the cylindrical plies extend over portions of the circular end 212 of the mandrel 210 to form a transition region 208.

[0070] Although monolithic composite structure 202 is depicted as having a plurality of cylindrical plies forming cylindrical portion 206 , according to illustrative examples, the composite structure may be laid up with a non-cylindrical body. In some illustrative examples, the composite structure may be one of a conical, elliptical, or other contoured portion rather than cylindrical portion 206 .

[0071] Now turn to Figure 3 , depicts an illustration of a front view of a dome top sheet of a dome portion of a composite structure according to an illustrative embodiment. The dome top sheet 302 in view 300 is Figure 1 In some illustrative examples, dome top sheet 302 has a physical implementation of one of multiple dome top sheets 108. Figure 1 The surface area of ​​dome top sheet 302 can be adjusted based on the design of the composite structure and the desired fiber angle gap. In some illustrative examples, dome top sheet 302 is Figure 1 The dome top sheet 302 may be present in Figure 2 In the monolithic composite structure 202 of FIG. Dome top sheet 302 includes a plurality of alternating paths 304 of a plurality of tows 306. Each path in plurality of alternating paths 304 includes a plurality of tows 306. In some illustrative examples, plurality of tows 306 includes sixteen tows. Plurality of tows 306 includes any desired number of tows.

[0072] A plurality of alternating paths 304 have been laid using guide vanes 308. Guide vanes 308 are Figure 1 In some illustrative examples, guide blade 308 is a physical implementation of any desired guide blade in plurality of guide blades 110. Figure 1308 is a physical implementation of first guide blade 126. In this illustrative example, guide blade 308 may be referred to as a reference guide blade. In some illustrative examples, guide blade 308 is oriented so that the Z axis is perpendicular to the vertex of the circular end of the mandrel. In some illustrative examples, guide blade 308 is oriented so that the Z axis is parallel to the longitudinal axis of the cylindrical surface of the mandrel. The x-axis and y-axis of guide blade 308 may have any desired orientation. In some illustrative examples, guide blade 308 is oriented so that one axis is parallel to the Z axis of a cylindrical guide blade (not shown). A cylindrical guide blade is a guide blade used to lay up a cylindrical portion of a monolithic composite structure.

[0073] In some illustrative examples, guide blade 308 is oriented so that one axis is perpendicular to the manufacturing floor and one axis is parallel to the manufacturing floor. In some illustrative examples, guide blade 308 is oriented so that the Z axis is parallel to the cylindrical surface of the mandrel.

[0074] The dome top sheet 302 has a zero degree angle relative to the guide vane 308. The dome top sheet 302 is laid without steering the plurality of tows 306. Since the dome top sheet 302 has a zero degree angle relative to the guide vane 308, the dome top sheet 302 can be laid without steering the plurality of tows 306.

[0075] Now turn to Figure 4 , depicts an illustration of a front view of a dome top sheet of a dome portion of a composite structure according to an illustrative embodiment. Dome top sheet 402 in view 400 is Figure 1 In some illustrative examples, dome top sheet 402 has a physical implementation of one of multiple dome top sheets 108. Figure 1 The surface area of ​​dome top sheet 402 can be adjusted based on the design of the composite structure and the desired fiber angle gap. In some illustrative examples, dome top sheet 402 is Figure 1 The dome top sheet 402 may be present in Figure 2 The dome top sheet 402 includes a plurality of alternating paths 404 of a plurality of tows 406. Each path in the plurality of alternating paths 404 includes a plurality of tows 406.

[0076] A plurality of alternating paths 404 have been laid using guide vanes 408. Guide vanes 408 are Figure 1 In some illustrative examples, guide blade 308 is a physical implementation of any desired guide blade in plurality of guide blades 110. Figure 11. The physical implementation of second guide blade 128 of FIG. 408. In this illustrative example, guide blade 408 has been rotated about the Z axis relative to guide blade 308. In some illustrative examples, the rotation about the Z axis may be referred to as "clocking." In this illustrative example, guide blade 408 has been clocked about 22.5 degrees relative to guide blade 308.

[0077] The dome top sheet 402 has a zero degree angle relative to the guide vane 408. Since the dome top sheet 402 is laid down at a zero degree angle relative to the guide vane 408, the dome top sheet 402 has been laid down without steering the plurality of tows 406. The dome top sheet 402 has an effective ply angle of 22.5 degrees relative to the guide vane 308 without steering the plurality of tows 406. The dome top sheet 402 may be referred to as a 22.5 degree ply.

[0078] Now turn to Figure 5 , depicts an illustration of a front view of a dome top sheet of a dome portion of a composite structure according to an illustrative embodiment. Dome top sheet 502 in view 500 is Figure 1 In some illustrative examples, dome top sheet 502 has a physical implementation of one of multiple dome top sheets 108. Figure 1 The surface area of ​​dome top sheet 502 can be adjusted based on the design of the composite structure and the desired fiber angle gap. In some illustrative examples, dome top sheet 502 is Figure 1 The dome top sheet 502 may be present in Figure 2 The dome top sheet 502 includes a plurality of alternating paths 504 of a plurality of tows 506. Each path in the plurality of alternating paths 504 includes a plurality of tows 506.

[0079] A plurality of alternating paths 504 have been laid using guide vanes 508. Guide vanes 508 are Figure 1 In some illustrative examples, guide 508 is a physical implementation of any desired guide in plurality of guides 110. Figure 1 1. The physical implementation of third guide vane 130 of FIG. 508. In this illustrative example, guide vane 508 has been clocked relative to guide vane 308. In this illustrative example, guide vane 508 has been clocked relative to guide vane 308 by approximately 45 degrees.

[0080] The dome top sheet 502 has a fiber angle of zero degrees relative to the guide vane 508. The dome top sheet 502 is laid down without steering the plurality of tows 506. The dome top sheet 502 has an effective ply angle of 45 degrees relative to the guide vane 308 without steering the plurality of tows 506. The dome top sheet 502 may be referred to as a 45 degree ply.

[0081] Now turn to Figure 6, depicts an isometric view of composite plies laid up on a mandrel, according to an illustrative embodiment. In view 600, a layup 601 includes a plurality of plies 602 laid up on a mandrel 604. The layup 601 includes Figure 1 At least one cylindrical layer of the plurality of cylindrical layers 168 and Figure 1 At least one dome top sheet of the plurality of dome top sheets 108. The stack 601 may be Figure 2 A portion of the monolithic composite structure 202. Figure 3 The dome top sheet 302 may be one layer of the stack 601 . Figure 4 The dome top sheet 402 may be one layer of the stack 601 . Figure 5 The dome top sheet 502 may be one layer of the stack 601 .

[0082] Plurality of plies 602 includes dome-shaped plies 606 and cylindrical plies 608. In this illustrative example, cylindrical plies 608 are zero degree plies. Transition region 610 is formed by the interaction between the dome-shaped plies on circular end 614 of the mandrel and the cylindrical plies on cylindrical surface 616 of mandrel 604.

[0083] The dome top sheet 606 is laid down on the rounded end 614 of the mandrel 604 using a guide vane 612. The guide vane 612 is timed relative to a reference guide vane 618. By timing the guide vane 612 relative to the reference guide vane 618, the dome top sheet 606 has an effective fiber angle of approximately 22.5 degrees. By laying down the dome top sheet 606 at a zero fiber angle relative to the guide vane 612, the dome top sheet 606 is laid down at an effective fiber angle of 22.5 degrees without using fiber steering.

[0084] The dome portion of the monolithic composite structure includes multiple sets of dome layer sheets laid up using multiple guides on the circular end 614 of the mandrel 604. The dome layer sheet 606 is one of the multiple sets of dome layers of the dome portion.

[0085] The cylindrical ply 608 is laid with a stacking guide independent of the guide 612 and parallel to the cylinder symmetry axis. The cylindrical ply 608 is laid with a stacking guide independent of the plurality of guides for laying the dome portion on the circular end 614 of the mandrel 604. As shown in view 600, the cylindrical ply 608 is laid on the edge of the dome ply 606.

[0086] In some illustrative examples, after laying up cylindrical ply 608, another cylindrical ply may be laid up over at least a portion of cylindrical ply 608. The other cylindrical ply may have any desired fiber angle depending on the design of the monolithic composite structure. The other cylindrical ply will be laid up using the same layup guide as cylindrical ply 608.

[0087] In some illustrative examples, after laying cylindrical ply 608, another dome ply can be laid over at least a portion of cylindrical ply 608. In some illustrative examples, after laying cylindrical ply 608, another dome ply can be laid adjacent to or with a slight gap from cylindrical ply 608. Depending on the design of the monolithic composite structure, the another dome ply can have any desired fiber angle. In some illustrative examples, the another dome ply can be laid using guide ply 612. In some illustrative examples, the another dome ply can be laid using a guide ply different from a guide ply.

[0088] A transition region may be formed between the dome portion and the cylindrical portion by varying the length of a plurality of dome plies of the dome portion and varying the length of a plurality of cylindrical plies of the cylindrical portion. In some illustrative examples, a next cylindrical ply laid over a portion of cylindrical ply 608 is shorter than cylindrical ply 608 to cover less circular end 614 of mandrel 604.

[0089] In some illustrative examples, the transition region includes a double scarf joint formed by alternately laying up groups of cylindrical plies and groups of dome-shaped plies on a cylindrical surface. The transition region may include any desired number of joints. In some illustrative examples, the transition region includes a plurality of joints staggered through the thickness of the monolithic composite structure.

[0090] Now turn to Figure 7 , depicts an isometric view of composite plies laid up on a mandrel according to an illustrative embodiment. In view 700, a layup 701 includes a plurality of plies 702 laid up on a mandrel 704. The layup 701 includes Figure 1 At least one cylindrical layer of the plurality of cylindrical layers 168 and Figure 1 At least one dome top sheet of the plurality of dome top sheets 108. The stack 701 may be Figure 2 A portion of the monolithic composite structure 202. Figure 3 The dome top sheet 302 may be one layer of the stack 701 . Figure 4 The dome top sheet 402 may be one layer of the stack 701 . Figure 5 The dome top sheet 502 may be one layer of the stack 701 .

[0091] The plurality of plies 702 includes a dome-shaped ply 706 and a cylindrical ply 708. In this illustrative example, the cylindrical ply 708 is a ninety degree ply. The transition region 710 is formed by the interaction between the dome-shaped ply on the circular end 714 of the mandrel and the cylindrical ply on the cylindrical surface 716 of the mandrel 704.

[0092] The dome top sheet 706 is laid down on the rounded end 714 of the mandrel 704 using a guide blade 712. The guide blade 712 is timed relative to a reference guide blade 718. By timing the guide blade 712 relative to the reference guide blade 718, the dome top sheet 706 has an effective fiber angle of approximately 90 degrees. By laying down the dome top sheet 706 at a zero fiber angle relative to the guide blade 712, the dome top sheet 706 is laid down at an effective fiber angle of 90 degrees without using fiber steering.

[0093] The dome portion of the monolithic composite structure includes multiple sets of dome layer sheets laid up using multiple guides on the circular end 714 of the mandrel 704. The dome layer sheet 706 is one of the multiple sets of dome layers of the dome portion.

[0094] The cylindrical ply 708 is laid up with a lamination guide that is independent of the guide 712. The cylindrical ply 708 is laid up with a lamination guide that is independent of the plurality of guides for laying up the dome portion on the circular end 714 of the mandrel 704. As shown in view 700, the cylindrical ply 708 is laid up on the edge of the dome ply 706.

[0095] In some illustrative examples, after laying up cylindrical ply 708, another cylindrical ply may be laid up over at least a portion of cylindrical ply 708. The other cylindrical ply may have any desired fiber angle depending on the design of the monolithic composite structure. The other cylindrical ply will be laid up using the same layup guide as cylindrical ply 708.

[0096] In some illustrative examples, after laying cylindrical ply 708, another dome ply can be laid over at least a portion of cylindrical ply 708. In some illustrative examples, after laying cylindrical ply 708, another dome ply can be laid adjacent to or with a slight gap from cylindrical ply 708. The another dome ply can have any desired fiber angle depending on the design of the monolithic composite structure. In some illustrative examples, the another dome ply can be laid using guide ply 712. In some illustrative examples, the another dome ply can be laid using a guide ply different from a guide ply.

[0097] A transition region may be formed between the dome portion and the cylindrical portion by varying the length of a plurality of dome plies of the dome portion and varying the length of a plurality of cylindrical plies of the cylindrical portion. In some illustrative examples, a next cylindrical ply laid over a portion of cylindrical ply 708 is shorter than cylindrical ply 708 to cover less circular end 714 of mandrel 704.

[0098] In some illustrative examples, the transition region includes a double scarf joint formed by alternately laying up groups of cylindrical plies and groups of dome-shaped plies on a cylindrical surface. The transition region may include any desired number of joints. In some illustrative examples, the transition region includes a plurality of joints staggered through the thickness of the monolithic composite structure.

[0099] Despite Figure 6 and Figure 7 In the embodiment of the present invention, the monolithic composite structure is described as having a plurality of cylindrical plies forming a cylindrical portion, but according to illustrative examples, the composite structure can be laid up with a non-cylindrical body. In some illustrative examples, the composite structure can be one of a conical, elliptical, or other contoured portion instead of a cylindrical portion.

[0100] Now turn to Figure 8 , depicts a flow chart of a method for laying up a monolithic composite structure according to an illustrative embodiment. The method 800 may be performed to lay up Figure 1 The method 800 may be performed to lay up the monolithic 104 composite structure 102. Figure 2 The monolithic composite structure 202 may be completed during the method 800. Figure 3 The dome top sheet 302 can be laid during method 800. Figure 4 The dome top sheet 402 can be laid during method 800. Figure 5 The method 800 may be performed to form a dome top sheet 502. Figure 6 The method 800 may be performed to form a stack 601. Figure 7 The stack 701.

[0101] Method 800 lays a plurality of dome-shaped plies on a circular end of a mandrel using a plurality of guides (operation 802). Method 800 lays a plurality of cylindrical plies on a cylindrical surface of a mandrel using a stacking guide independent of the plurality of guides (operation 804). Method 800 forms a transition region including a joint between the plurality of dome-shaped plies and the plurality of cylindrical plies by varying the lengths of the plurality of dome-shaped plies and the plurality of cylindrical plies (operation 805). Thereafter, method 800 terminates.

[0102] In some illustrative examples, laying up the plurality of dome plies includes laying up a plurality of groups of plies, wherein each group of plies in the plurality of groups of plies is laid up at a zero degree fiber angle relative to a corresponding guide vane in the plurality of guide vanes (operation 806). By laying up each ply at a zero degree fiber angle relative to the corresponding guide vane, each ply can be laid up at a desired effective fiber angle without an undesirable amount of fiber steering. Each group of plies includes any desired number of plies.

[0103] In some illustrative examples, laying down each of the plurality of dome layers includes laying down a plurality of alternating paths, wherein each of the plurality of alternating paths includes a plurality of tows (operation 808 ). The plurality of tows includes any desired number of tows.

[0104] In some illustrative examples, forming the transition region includes forming a joint completely on the circular end of the mandrel (operation 810). The lengths of the plurality of dome-shaped plies and the plurality of cylindrical plies can vary by any desired amount. In some illustrative examples, the lengths of the plurality of dome-shaped plies can vary by approximately 0.5 inches.

[0105] In some illustrative examples, forming the transition region includes alternately laying down a plurality of dome plies and a plurality of cylindrical plies to form a joint (operation 812). Any desired number of dome plies may be laid down before laying down the cylindrical plies. In addition, the number of dome plies laid down before laying down a subsequent number of cylindrical plies is independent of other numbers of dome plies laid down previously.

[0106] In some illustrative examples, the plurality of guide blades includes at least four guide blades (operation 814). In some illustrative examples, the plurality of guide blades includes six guide blades. In some illustrative examples, the plurality of guide blades includes more than six guide blades.

[0107] In some illustrative examples, method 800 cures the plurality of dome top sheets and the plurality of cylindrical plies on a mandrel (operation 816). The plurality of dome top sheets and the plurality of cylindrical plies are co-cured on the mandrel. By co-curing the plurality of dome top sheets and the plurality of cylindrical plies on the mandrel, a monolithic composite structure having a dome portion, a cylindrical portion, and a transition region between the dome portion and the cylindrical portion is formed. By co-curing the plurality of dome top sheets and the plurality of plies on the mandrel, a monolithic composite structure having a cabin shape is formed.

[0108] In some illustrative examples, laying a plurality of cylindrical plies includes: rotating the mandrel during laying a plurality of cylindrical plies (operation 818). In some illustrative examples, rotating the mandrel allows the composite laying head to remain on track.

[0109] In some illustrative examples, method 800 divides one hundred eighty degrees into equal increments to set the timing offsets of the plurality of guide vanes (operation 820). In some illustrative examples, each guide vane is approximately equally offset from an adjacent guide vane.

[0110] Now turn to Fig. 9 , depicts a flow chart of a method for laying up a composite structure according to an illustrative embodiment. The method 900 may be performed to lay up Figure 1 The method 900 may be performed to lay up the monolithic 104 composite structure 102. Figure 2The monolithic composite structure 202 may be completed during method 900. Figure 3 The dome top sheet 302 can be laid during method 900. Figure 4 The dome top sheet 402 can be laid during method 900. Figure 5 The method 900 may be performed to form a dome top sheet 502. Figure 6 The method 900 may be performed to form a stack 601. Figure 7 The stack 701.

[0111] Method 900 lays up a plurality of dome plies on a circular end of a mandrel (operation 902). In method 900, laying up the plurality of dome plies includes laying up a first set of plies on the circular end of the mandrel at a zero degree fiber angle using a first guide vane (operation 906). In method 900, laying up the plurality of dome plies includes laying up a second set of plies on the circular end of the mandrel at a zero degree fiber angle using a second guide vane offset from the first guide vane (operation 908). In method 900, laying up the plurality of dome plies includes laying up a third set of plies on the circular end of the mandrel at a zero degree fiber angle using a third guide vane offset from both the first guide vane and the second guide vane (operation 910).

[0112] The method 900 lays the plurality of cylindrical plies on the cylindrical surface of the mandrel to contact the plurality of dome plies (operation 904). The method 900 varies the lengths of the plurality of dome plies and the plurality of cylindrical plies to form joints between the plurality of dome plies and the plurality of cylindrical plies (operation 912). By varying the lengths of the plurality of dome plies and the plurality of cylindrical plies, any desired type of joint may be formed. Thereafter, the method 900 terminates.

[0113] In some illustrative examples, a joint is formed entirely on the circular end of the mandrel (operation 913 ).

[0114] In some illustrative examples, laying up the plurality of cylindrical plies includes alternately laying up the plurality of groups of cylindrical plies and the plurality of groups of dome plies to form joints between the plurality of dome plies and the plurality of cylindrical plies (operation 914). The plurality of groups of cylindrical plies and the plurality of groups of dome plies are laid up in coordination to form the joints.

[0115] In some illustrative examples, laying each of the plurality of dome layers includes laying a plurality of alternating paths, wherein each of the plurality of alternating paths includes a plurality of tows (operation 916). Each of the plurality of alternating paths includes the same plurality of tows. In some illustrative examples, the plurality of tows includes at least 16 tows.

[0116] 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.

[0117] As used herein, "plurality" when used with reference to items means one or more items.

[0118] 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.

[0119] 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 806 to 820 may be optional. As another example, operations 906 to 916 may be optional.

[0120] You can Fig.10 Aircraft manufacturing and service method 1000 is shown and described below. Fig.11 Illustrative embodiments of the present disclosure are described in the context of aircraft 1100 as shown. Fig.10 , an illustration of an aircraft manufacturing and service method in block diagram form is depicted according to an illustrative embodiment. During pre-production, aircraft manufacturing and service method 1000 may include Fig.11 Specification and design 1002 of the aircraft 1100 and material procurement 1004.

[0121] During production, component and subassembly manufacturing 1006 and system integration 1008 of the aircraft 1100 occurs. Thereafter, the aircraft 1100 may undergo certification and delivery 1010 for entry into 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.

[0122] 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 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.

[0123] Reference now Fig.11 , depicts an illustration of an aircraft in block diagram form in which an illustrative embodiment may be implemented. In this example, aircraft 1100 is Fig.10 Aircraft manufacturing and service method 1000 is produced and may include airframe 1102 having multiple systems 1104 and interior 1106. Examples of systems 1104 include one or more of propulsion system 1108, electrical system 1110, hydraulic system 1112, and environmental system 1114. Any number of other systems may be included.

[0124] Apparatus and methods embodied herein may be employed during at least one of the stages of aircraft manufacturing and service method 1000. One or more illustrative embodiments may be employed in Fig.10 The components and subassemblies are manufactured or used during at least one of manufacturing 1006 , system integration 1008 , service 1012 , or maintenance and service 1014 .

[0125] Illustrative examples provide methods for placing monolithic dome / cylinder structures using hybrid guides. In some illustrative examples, a method cantilever a dome / cylinder tool. An illustrative example fiber places a dome cover layer with a 0 degree guide perpendicular to the axis of symmetry. Each of the plurality of guides is rotated about the surface normal at the vertex of the dome (the axis of symmetry or the Z axis of the reference guide). An illustrative example fiber places a cylinder ply with a 0 degree guide parallel to the axis of symmetry. An illustrative example crosses the interface of the dome staggered plies for a hybrid effect. An illustrative example co-cures a dome / cylinder structure.

[0126] In illustrative examples, the dome top sheet has separate guide sheet references. In illustrative examples, the dome top sheet is timed in desired amounts. In some non-limiting illustrative examples, the dome top sheet is timed in '22.5 degree increments (0, 22.5, 45, 67.5, 90, 112.5, 135, 157.5) to maintain a desired angular gap through the thickness. In some illustrative examples, maintaining the desired angular gap includes minimizing variation. The angular gap is the maximum angle between adjacent fiber directions through the thickness. In some illustrative examples, the ply interfaces are separated by 0.5". In other illustrative examples, the ply interfaces can be separated by more or less than 0.5".

[0127] In some illustrative examples, the next sequential interface is positioned between the previous interfaces so as to distribute the interfaces through the thickness. There can be any desired number of effective fiber angles in the dome portion. In some illustrative examples, the dome portion includes 4 orientations. In some illustrative examples, the dome portion includes 6 orientations. In some illustrative examples, the dome portion includes at least 8 orientations (i.e., 22.5 degree increments) to reduce the angle gap. More angles will give you more uniform properties.

[0128] The illustrative examples present a cylinder and dome fiber placed as one piece using 2 separate placement techniques. The illustrative examples utilize a cantilevered tool on a rotator. The illustrative examples include domes and cylinders laid simultaneously. In some illustrative examples, the cylinder is laid first. The head of the automated placement system rotates for the dome. The cylinder and dome have separate guide sheet references. The dome sheets are timed in approximately equal increments. In some illustrative examples, the increments may be 0, 22.5, 45, 67.5, 90, 112.5, 135, 157.5. In some illustrative examples, the increments are selected so as to maintain a minimum angular gap through the thickness. The angular gap is equal to the difference in fiber angles of two adjacent fiber directions through the thickness.

[0129] 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.

[0130] CROSS-REFERENCE TO RELATED APPLICATIONS

[0131] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 584,694, filed on September 22, 2023, entitled “Unitary Composite Structure,” the entire contents of which are incorporated herein by reference.

Claims

1. A method (800) of laying up a monolithic (104) composite structure (102, 202), the method comprising: laying (802) a plurality of dome-shaped top sheets (108, 216) onto the circular end (116, 212) of the mandrel (118, 210) using a plurality of guide sheets (110, 308, 408, 508); laying (804) a plurality of cylindrical plies (168, 218) onto a cylindrical surface (120, 214) of the mandrel (118, 210) using a lamination guide (114) that is independent of the plurality of guides (110, 308, 408, 508); and By varying the length (137) of the plurality of dome-shaped top sheets (108, 216) and the length (182) of the plurality of cylindrical plies (168, 218), a transition region (184, 208) including a joint (186) is formed (805) between the plurality of dome-shaped top sheets (108, 216) and the plurality of cylindrical plies (168, 218).

2. The method (800) of claim 1, wherein: Laying down the plurality of dome-shaped layer sheets (108, 216) comprises laying down (806) a plurality of groups of plies (109), wherein each group of plies (138, 140, 142, 144, 146, 148) in the plurality of groups of plies (109) is laid down at a zero degree fiber angle (ref#) according to a corresponding guide sheet (126, 128, 130, 132, 134, 136) in the plurality of guide sheets (110, 308, 408, 508).

3. The method (800) of claim 1, wherein: Laying down each dome top sheet (ref#) of the plurality of dome top sheets (108, 216) includes laying down (808) a plurality of alternating paths (123, 304, 404, 504), wherein each path (ref#) of the plurality of alternating paths (123, 304, 404, 504) includes a plurality of tows (122, 306, 406, 506).

4. The method (800) of claim 1, wherein: Forming the transition region (184, 208) includes forming (810) the joint (186) entirely on the circular end (116, 212) of the mandrel (118, 210).

5. The method (800) of claim 1, wherein: Forming the transition region (184, 208) includes alternately laying down (812) the plurality of dome-shaped plies (108, 216) and the plurality of cylindrical plies (168, 218) to form the joint (186).

6. The method (800) of claim 1, wherein: The plurality of guide vanes (110, 308, 408, 508) includes (814) at least four guide vanes (164, 126, 128, 130, 132).

7. The method (800) of claim 1, further comprising: The plurality of dome-shaped plies (108, 216) and the plurality of cylindrical plies (168, 218) are cured (816) on the mandrel (118, 210).

8. The method (800) of claim 1, further comprising: One hundred eighty degrees is divided (820) into equal increments (ref#) to set the timing offset (166) of the plurality of guide blades (110, 308, 408, 508).

9. The method (800) of claim 1, wherein: Laying up the plurality of cylindrical plies (168, 218) includes rotating (818) the mandrel (118, 210) during laying up the plurality of cylindrical plies (168, 218).

10. A monolithic (104) composite structure (102, 202), the monolithic (104) composite structure (102, 202) comprising: a dome portion (106, 204) comprising a plurality of groups of plies (109) laid using a plurality of guide vanes (110, 308, 408, 508); a cylindrical portion (112, 206) laid using a stacked guide vane (114) independent of the plurality of guide vanes (110, 308, 408, 508); as well as A transition region (184, 208) is provided between the dome portion (106, 204) and the cylindrical portion (112, 206), the transition region being formed by varying the length (137) of a plurality of dome-shaped layer sheets (108, 216) of the dome portion (106, 204) and by varying the length (182) of a plurality of cylindrical layer sheets (168, 218) of the cylindrical portion (112, 206).

11. The monolithic (104) composite structure (102, 202) of claim 10, wherein: The integral (104) composite structure (102, 202) has a half-cabin 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 the edge of the cylindrical portion (112, 206); and wherein the body (195) is formed by the cylindrical portion (112, 206).

12. The monolithic (104) composite structure (102, 202) of claim 10, wherein: The transition region (184, 208) includes a double-peg joint formed by alternately laid sets of cylindrical plies (170, 172, 174, 176, 178, 180) and sets of dome-shaped plies (138, 140, 142, 144, 146, 148).

13. The monolithic (104) composite structure (102, 202) of claim 10, wherein: The dome portion (106, 204) includes a number of fiber angles (150, 152, 154, 156, 158, 160) equal to the number (164) of guide vanes in the plurality of guide vanes (110, 308, 408, 508).

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

15. The monolithic (104) composite structure (102, 202) of claim 10, wherein: The plurality of guide vanes (110, 308, 408, 508) includes at least four guide vanes.

16. The monolithic (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) of laying up a composite structure (102, 202), the method comprising: Laying (902) a plurality of dome-shaped top sheets (108, 216) on a circular end (116, 212) of a mandrel (118, 210), laying the plurality of dome-shaped top sheets (108, 216) comprises: laying (906) a first set of plies (138, 302) onto a circular end (116, 212) of a mandrel (118, 210) at a zero degree fiber angle using a first guide (126, 308); laying (908) a second set of plies (140, 402) onto the circular end (116, 212) of the mandrel (118, 210) at a zero degree fiber angle using a second guide (128, 408) offset from the first guide (126, 308); and laying (910) a third set of plies (142, 502) on the circular end (116, 212) of the mandrel (118, 210) at a zero degree fiber angle using a third guide (130, 508) offset from both the first guide (126, 308) and the second guide (128, 408); laying (902) a plurality of cylindrical plies (168, 218) on the cylindrical surface (120, 214) of the mandrel (118, 210) to contact the plurality of dome-shaped plies (108, 216); and The lengths (182, 137) of the plurality of dome-shaped top sheets (108, 216) and the plurality of cylindrical plies (168, 218) are varied (912) to form joints (186) between the plurality of dome-shaped top sheets (108, 216) and the plurality of cylindrical plies (168, 218).

18. The method (900) of claim 17, wherein: The joint (186) is formed completely on the circular end (116, 212) of the mandrel (118, 210).

19. The method (900) of claim 17, wherein: Laying down the plurality of cylindrical plies (168, 218) includes alternately laying down (914) a plurality of groups of cylindrical plies (170, 172, 174, 176, 178, 180) and a plurality of groups of dome-shaped top sheets (138, 140, 142, 144, 146, 148) to form joints (186) between the plurality of dome-shaped top sheets (108, 216) and the plurality of cylindrical plies (168, 218).

20. The method (900) of claim 17, wherein: Laying down each of the plurality of dome top sheets (108, 216) includes laying down (916) a plurality of alternating paths (123, 304, 404, 504), wherein each of the plurality of alternating paths (123, 304, 404, 504) includes a plurality of tows (122, 306, 406, 506).

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