Metal-composite joint

Abstract

To provide a metal-composite joint.SOLUTION: A metal-composite joint and a method for forming the same are presented. The metal-composite joint for a platform comprises two metal structural components forming a portion of a first surface and a portion of a second surface of the metal-composite joint, and a set of composite ply segments between the two metal structural components providing an escape path for volatile substances between the two metal structural components.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 660,313, filed June 14, 2024, which is incorporated herein by reference in its entirety. This application is related to U.S. Patent Application No. _________, entitled "Composite Panels with Titanium Ends," filed on that date and assigned to the same assignee, attorney docket number 24-0409-US-NP.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to forming composite joints, and more particularly to forming metal to composite joints. [Background technology]

[0003] In aircraft, metal-composite joints may be used to join wings to the body of the aircraft. The metal-composite joints may be step-lap joints between composite plies and metal components. In large structures, metal-composite joints present manufacturing challenges.

[0004] Gaps form at each step of a step-lap metal-composite joint, allowing air to enter the laminate. In thicker sections, the air and volatiles inside the laminate at the step are undesirably difficult to evacuate during fabrication and autoclave curing. The remaining air and volatiles can result in undesirable conditions, such as porosity. To reduce inconsistencies, multiple cure cycles can be used to increase cycle time and utilize more resources. Summary of the Invention [Problem to be solved by the invention]

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

[0006] One embodiment of the present disclosure provides a metal-composite joint for a platform, the metal-composite joint comprising two metal structural components forming a portion of a first surface and a portion of a second surface of the metal-composite joint, and a split set of composite plies between the two metal structural components that provides an escape path for volatile materials between the two metal structural components.

[0007] Another embodiment of the present disclosure provides a metal-composite joint for a platform, the metal-composite joint comprising: a first metal structural component having a stepped surface and a flat surface, a first set of composite plies having faying surfaces complementary to the stepped surface of the first metal structural component, a second metal structural component having a stepped surface and a flat surface, a second set of composite plies having faying surfaces complementary to the stepped surface of the second metal structural component, and a split set of composite plies between the two metal structural components, the split set providing an escape path for volatile materials between the two metal structural components.

[0008] Yet another embodiment of the present disclosure provides a method of forming a structural metallic-composite joint, wherein a segmented set of composite plies is placed on a first metallic structural component, a second metallic structural component is placed on the segmented set of composite plies, and the first metallic structural component and the second metallic structural component are bonded to the segmented set of composite plies.

[0009] A still further embodiment of the present disclosure provides a method for removing volatiles from a metal-composite joint in a structure. The metal-composite joint is laid up with a split set of composite plies between a first metal structural component and a second metal structural component. The first metal structural component and the second metal structural component are bonded to the split set of composite plies. Volatiles are evacuated along the split set of composite plies and between the first metal structural component and the second metal structural component during bonding.

[0010] The features and functions may be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings.

[0011] The novel features believed characteristic of the exemplary embodiments are set forth in the appended claims. However, the exemplary embodiments, as well as their preferred modes of use, further objects and features, will best be understood by reference to the following detailed description of exemplary embodiments of the present disclosure, when considered in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is an illustration of an aircraft in accordance with an illustrative embodiment; [Figure 2] FIG. 1 is a block diagram of a manufacturing environment in accordance with an illustrative embodiment. [Figure 3] 1 is a cross-sectional view of a metallic composite joint in accordance with an exemplary embodiment; [Figure 4] 1 is a cross-sectional view of a metallic composite joint in accordance with an exemplary embodiment; [Figure 5] 1 is a cross-sectional view of a metallic composite joint in accordance with an exemplary embodiment; [Figure 6] 1 is a flowchart of a method for forming a metallic composite bond in a structure in accordance with an illustrative embodiment. [Figure 7] 1 is a flowchart of a method for releasing volatiles from a metal-composite joint in a structure in accordance with an illustrative embodiment. [Figure 8] 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 9] 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 INVENTION

[0013] The illustrative examples recognize and take into account one or more considerations: The illustrative examples recognize and take into account that smaller composite parts have fewer problems venting volatiles; The illustrative examples recognize and take into account that smaller composite parts have fewer volatiles because the volatiles travel between the plies as opposed to through the thickness; The illustrative examples recognize and take into account that air / volatiles travel significantly better between the plies than through the thickness.

[0014] The illustrative examples recognize and take into account that volatiles cannot migrate through titanium. The illustrative examples recognize and take into account that hybrid titanium composite parts help reduce weight compared to titanium parts.

[0015] Illustrative examples provide new designs that include titanium and carbon fiber composites that can be used in aircraft wing skins. In these illustrative examples, the titanium is bonded to at least one edge of a large composite structure.

[0016] Illustrative examples show metal-composite joints with two or more titanium components through the thickness. Illustrative examples "split" a large titanium part into two pieces, allowing for composite between them. Illustrative examples provide an escape path for air and volatiles through the composite layer between the titanium parts.

[0017] Illustrative examples improve both manufacturability and damage tolerance for titanium and composite structures. Splitting the titanium and using composite layers between titanium components helps manage scale for designs with titanium inside large wing skins or other significant portions. Illustrative examples can be used on the inboard and outboard edges of the wing skin to reduce weight.

[0018] Referring now to Figure 1, an illustration of an aircraft is shown in accordance with an illustrative embodiment. Aircraft 100 has wing 102 and wing 104 attached to body 106. Aircraft 100 includes engine 108 attached to wing 102 and engine 110 attached to wing 104.

[0019] The body 106 has a tail section 112. A horizontal stabilizer 114, a horizontal stabilizer 116, and a vertical stabilizer 118 are attached to the tail section 112 of the body 106.

[0020] Aircraft 100 is an example of an aircraft that may have metal-composite joints formed using the illustrative examples. The illustrative example metal-composite joints may be used to connect at least one of wing 102 or wing 104 to body 106.

[0021] With reference now to Figure 2, an illustration of a block diagram of a manufacturing environment is depicted. Metal-composite joint 210 of platform 202 may be formed in manufacturing environment 200 in accordance with an illustrative embodiment.

[0022] Platform 202 may take many different forms. For example, platform 202 may be selected from the group including a mobile platform, a fixed platform, a land structure, an underwater structure, a space structure, an aircraft, a commercial aircraft, a rotorcraft, a tiltrotor aircraft, a tilt-wing aircraft, a vertical take-off and landing aircraft, an electric vertical take-off and landing vehicle, a personal air vehicle, a tanker aircraft, a surface vessel, a tank, a personnel carrier, a train, a spacecraft, a space station, a satellite, a submarine, an automobile, a power plant, a bridge, a dam, a house, a manufacturing facility, a building, a robot, a robotic arm, a crane, and other suitable types of platforms.

[0023] In some illustrative examples, platform 202 may be aircraft 204. In some illustrative examples, platform 202 is wing 206 of aircraft 204.

[0024] 1 may be a physical implementation of aircraft 204. In some illustrative examples, when metal-composite joint 210 is part of aircraft 204, metal-composite joint 210 may connect wing 206 to body 208 of aircraft 204.

[0025] Metal-composite joint 210 for platform 202 comprises first metal structural component 212 and second metal structural component 214 with sub-set of composite plies 222 between first metal structural component 212 and second metal structural component 214. As used herein, an item "set" means one or more items. Sub-set of composite plies 222 comprises one or more composite plies. Sub-set of composite plies 222 provides escape paths 224 for volatiles 223 within metal-composite joint 210. Escape paths 224 extend between layers within metal-composite joint 210 for platform 202.

[0026] Metal-composite joint 210 for platform 202 includes a first metal structural component 212, a first set of composite plies 230, a second metal structural component 214, a second set of composite plies 232, and a split set of composite plies 222. First metal structural component 212 includes a stepped surface 216 and a flat surface 218. First set of composite plies 230 include a joining surface complementary to stepped surface 216 of first metal structural component 212. Second metal structural component 214 includes a stepped surface 221 and a flat surface 220. Second set of composite plies 232 include a joining surface complementary to stepped surface 221 of second metal structural component 214. Split set of composite plies 222 between the two metal structural components provides an escape path 224 for volatiles 223 between the two metal structural components. In some illustrative examples, first set of composite plies 230 are described as abutting stepped surfaces 216 of first metallic structural component 212. In some illustrative examples, second set of composite plies 232 are described as abutting stepped surfaces 221 of second metallic structural component 214.

[0027] In some illustrative examples, first set of composite plies 230 are complementary to first metal structural component 212 to form lap joint 242. Lap joint 242 comprises faying surfaces 248 of first metal structural component 212 and first set of composite plies 230. In some illustrative examples, second set of composite plies 232 are complementary to second metal structural component 214 to form lap joint 243. Lap joint 243 comprises faying surfaces 250 of second metal structural component 214 and second set of composite plies 232. Split set of composite plies 222 extends between first set of composite plies 230 and second set of composite plies 232.

[0028] In some illustrative examples, segmented set of composite plies 222 extends between and is bonded to flat surfaces of two metal structural components, i.e., flat surface 218 of first metal structural component 212 and flat surface 220 of second metal structural component 214. In some illustrative examples, segmented set of composite plies 222 extends between and is bonded to stepped surfaces of two metal structural components, i.e., stepped surface 216 of first metal structural component 212 and stepped surface 221 of second metal structural component 214.

[0029] In some illustrative examples, first metal structural component 212 and second metal structural component 214 comprise titanium. As shown, first metal structural component 212 comprises titanium 213. As shown, second metal structural component 214 comprises titanium 215.

[0030] Metal-composite joint 210 comprises any desired amount of metal structural components with split composite plies between the metal structural components. In some illustrative examples, metal-composite joint 210 for platform 202 comprises two metal structural components forming a portion of first surface 226 and a portion of second surface 228 of metal-composite joint 210, and a split set 222 of composite plies between the two metal structural components, the split set 222 providing an escape path 224 for volatile materials 223 between the two metal structural components.

[0031] In some illustrative examples, stepped surface 216 of first metallic structural component 212 forms a portion of first surface 226. In some illustrative examples, flat surface 218 forms a portion of first surface 226. The remainder of first surface 226 is formed by first set of composite plies 230. In some illustrative examples, first ply stack 234 of first set of composite plies 230 forms a portion of first surface 226.

[0032] In some illustrative examples, stepped surface 221 of second metal structural component 214 forms a portion of second surface 228. In some illustrative examples, flat surface 220 forms a portion of second surface 228. The remaining portion of second surface 228 is formed by second set of composite plies 232. In some illustrative examples, first ply stack 234 of first set of composite plies 230 forms a portion of first surface 226.

[0033] First set of composite plies 230 comprises a faying surface 248 with first metal structural component 212 of the two metal structural components, and second set of composite plies 232 comprises a faying surface 250 with second metal structural component 214 of the two metal structural components, forming lap joint 242 and lap joint 243. In some illustrative examples, first set of composite plies 230 can be described as abutting first metal structural component 212 of the two metal structural components, and second set of composite plies 232 can be described as abutting second metal structural component 214 of the two metal structural components, forming lap joint 242 and lap joint 243. First set of composite plies 230 forms lap joint 242 with stepped surface 216 of first metal structural component 212. At lap joint 242, the length of the ply stack of first set of composite plies 230 changes to form a joint with stepped surface 216 of first metal structural component 212. The second set of composite plies 232 form a lap joint 243 with the stepped surface 221 of the second metal structural component 214. At the lap joint 243, the length of the ply stack of the second set of composite plies 232 changes to form a joint with the stepped surface 221 of the second metal structural component 214.

[0034] When stepped surface 216 forms part of first surface 226, first metal structural component 212 extends into first set of composite plies 230. When stepped surface 216 forms part of first surface 226, the longest ply of first set of composite plies 230 forms part of first surface 226. In these illustrative examples, length 235 of first ply stack 234 forming part of first surface 226 is longer than length 237 of plies in second ply stack 236. Second ply stack 236 is further from metal-composite joint 210 through thickness 246 moving from first surface 226 to second surface 228.

[0035] When stepped surface 221 forms part of second surface 228, second metal structural component 214 extends into second set of composite plies 232. When stepped surface 221 forms part of second surface 228, the longest ply of second set of composite plies 232 forms part of second surface 228. In these illustrative examples, length 241 of fourth ply stack 240, which forms part of second surface 228, is longer than length 239 of plies in third ply stack 238. Third ply stack 238 is further from metal-composite joint 210 through thickness 246 moving from second surface 228 to first surface 226.

[0036] In these illustrative examples, first metallic structural component 212 and second metallic structural component 214 are seen to extend within the composite material of first set of composite plies 230 and second set of composite plies 232. In other illustrative examples, the composite material of first set of composite plies 230 and second set of composite plies 232 are seen to extend between first metallic structural component 212 and second metallic structural component 214.

[0037] When the composite material of first set of composite plies 230 and second set of composite plies 232 is viewed as extending between first metal structural component 212 and second metal structural component 214, the composite plies forming first surface 226 and second surface 228 have the shortest length of first set of composite plies 230 and second set of composite plies 232.

[0038] In some illustrative examples, segmented set of composite plies 222 is bonded to two metal structural components. In some illustrative examples, structural adhesive 244 is applied to at least one of segmented set of composite plies 222, first metal structural component 212, or second metal structural component 214.

[0039] Although not shown in metal-composite joint 210, a third metal structural component may be present between the two metal structural components. In these illustrative examples, split set 222 of composite plies is bonded to the two metal structural components and one of the third metal structural components.

[0040] In some illustrative examples, the two metal structural components, first metal structural component 212 and second metal structural component 214, are symmetrical about the center of metal-composite joint 210 through thickness 246. In other illustrative examples, the two metal structural components, first metal structural component 212 and second metal structural component 214, are asymmetrical about the center of metal-composite joint 210 through thickness 246. In some illustrative examples, the two metal structural components, first metal structural component 212 and second metal structural component 214, have the same design. In other illustrative examples, the two metal structural components, first metal structural component 212 and second metal structural component 214, have different designs.

[0041] In some illustrative examples, structural adhesive 244 covers the faying surfaces of two metal structural components having first set of composite plies 230 and second set of composite plies 232. In some illustrative examples, structural adhesive 244 extends at least partially between first set of composite plies 230 and segmented set of composite plies 222. In some illustrative examples, structural adhesive 244 extends partially within first set of composite plies 230. In some illustrative examples, structural adhesive 244 extends at least partially between second set of composite plies 232 and segmented set of composite plies 222. In some illustrative examples, structural adhesive 244 extends partially within second set of composite plies 232.

[0042] In some illustrative examples, segmented sets of composite plies 222 are bonded to flat surfaces of first metal structural component 212 and second metal structural component 214. In some illustrative examples, segmented sets of composite plies 222 are bonded to stepped surfaces of first metal structural component 212 and second metal structural component 214.

[0043] The illustration of manufacturing environment 200 in FIG. 2 is not meant to imply physical or architectural limitations to the manner in which an illustrative embodiment may be implemented. Other components in addition to or in place of the illustrated components may be used. Some components may be unnecessary. Also, the blocks are presented to illustrate some functional components. One or more of these blocks may be combined, divided, or combined and divided into different blocks when implemented in an illustrative embodiment.

[0044] For example, there may be more than two metal structural components. As another example, when there are more than two metal structural components, there may be more than two sets of split composite plies.

[0045] Referring now to Figure 3, a cross-sectional view of a metallic-composite joint is illustrated in accordance with an exemplary embodiment. Metallic-composite joint 300 is a physical implementation of metal-composite joint 210 of Figure 2. Metallic-composite joint 300 comprises a metallic structural component 302 and a composite material 304. Metallic structural component 302 comprises a first metallic structural component 306 and a second metallic structural component 308.

[0046] Two metallic structural components, first metallic structural component 306 and second metallic structural component 308, form a portion of first surface 316 and a portion of second surface 318 of metal-composite joint 300. Segmented set of composite plies 310 are between the two metallic structural components and provide an escape path 311 for volatiles between the two metallic structural components. In this illustrative example, volatiles can escape metal-composite joint 300 by traveling between layers along segmented set of composite plies 310.

[0047] In this illustrative example, segmented-set of composite plies 310 is adhered to two metal structural components, first metal structural component 306 and second metal structural component 308. In this illustrative example, segmented-set of composite plies 310 is bonded to planar surface 322 of first metal structural component 306 and planar surface 326 of second metal structural component 308. In this illustrative example, structural adhesive 328 adheres segmented-set of composite plies 310 to each of planar surfaces 322 and 326.

[0048] Sub-set of composite plies 310 may comprise any desired quantity of composite plies, hi some illustrative examples, sub-set of composite plies 310 may comprise a stack of six composite plies.

[0049] First metal structural component 306 comprises a stepped surface 320 and a flat surface 322. Second metal structural component 308 comprises a stepped surface 324 and a flat surface 326. First set of composite plies 312 comprises a mating surface complementary to first metal structural component 306 of the two metal structural components. Second set of composite plies 314 comprises a mating surface complementary to second metal structural component 308 of the two metal structural components. First set of composite plies 312 is complementary to first metal structural component 306. Second set of composite plies 314 is complementary to second metal structural component 308.

[0050] The first set of composite plies 312 includes a first ply stack 330, a second ply stack 332, a third ply stack 334, and a fourth ply stack 336. The second set of composite plies 314 includes a fifth ply stack 338, a sixth ply stack 340, a seventh ply stack 342, and an eighth ply stack 344.

[0051] In some illustrative examples, a manufacturable gap may exist between first set of composite plies 312 and stepped surface 320 of first metallic structural component 306. In some illustrative examples, a manufacturable gap may exist between second set of composite plies 314 and stepped surface 324 of second metallic structural component 308. Volatiles from the gap may vent through escape path 311 during processing of metal-composite joint 300.

[0052] In this illustrative example, two metallic structural components, first metallic structural component 306 and second metallic structural component 308, are symmetrical about center 348 of metal-composite joint 300 through thickness 346. In this illustrative example, flat surface 322 faces flat surface 326 around center 348 of metal-composite joint 300 through thickness 346. In this illustrative example, the longest composite ply of first set of composite plies 312 forms a portion of first surface 316. In this illustrative example, the longest composite ply of second set of composite plies 314 forms a portion of second surface 318. In this illustrative example, the longest portions of stepped surface 320 and stepped surface 324 are near center 348, so the two metallic structural components appear to “extend into” the composite material.

[0053] Split set of composite plies 310 extends between first set of composite plies 312 and second set of composite plies 314. First set of composite plies 312 forms a lap joint with stepped surface 320 of first metal structural component 306. Second set of composite plies 314 forms a lap joint with stepped surface 324 of second metal structural component 308.

[0054] In this illustrative example, structural adhesive 328 covers the faying surfaces of two metal structural components, first metal structural component 306 and second metal structural component 308, having first set of composite plies 312 and second set of composite plies 314. In this illustrative example, structural adhesive 328 bonds first set of composite plies 312 to first metal structural component 306. In this illustrative example, structural adhesive 328 bonds second set of composite plies 314 to second metal structural component 308. In this illustrative example, structural adhesive 328 extends partially between some ply stacks of first set of composite plies 312. As shown, structural adhesive 328 extends partially between third ply stack 334 and fourth ply stack 336. As shown, structural adhesive 328 extends partially between fourth ply stack 336 and split set of composite plies 310. As shown, structural adhesive 328 extends partially between split set of composite plies 310 and fifth ply stack 338. As shown, structural adhesive 328 extends partially between fifth ply stack 338 and sixth ply stack 340.

[0055] In some illustrative examples, the two metal structural components, first metal structural component 306 and second metal structural component 308, comprise titanium. In some illustrative examples, titanium is used based on its compressive strength.

[0056] In some illustrative examples, metal-composite joint 300 may be a component of an aircraft wing, hi some illustrative examples, metal-composite joint 300 may connect an aircraft wing to the body of the aircraft.

[0057] As shown, the two metal structural components include a first metal structural component 306 having a stepped surface 320 and a flat surface 322, and a second metal structural component 308 having a stepped surface 324 and a flat surface 326. In this illustrative example, the flat surfaces of first metal structural component 306 and second metal structural component 308 are inside the platform. In this illustrative example, the stepped surfaces of first metal structural component 306 and second metal structural component 308 form part of the surface of the platform.

[0058] Metal-composite joint 300 is a non-limiting example. In this illustrative example, metal-composite joint 300 is symmetrical about center 348 through thickness 346. In other illustrative examples, metal-composite joint 300 may be asymmetrical. While four metal structural components are shown, the metal-composite joint of the illustrative example can have any desired amount of metal structural components. Additionally, while metal structural components 302 each extend an equal distance into the composite material, in other illustrative examples, at least one metal structural component may be a different size, shape, or other configuration.

[0059] Referring now to Figure 4, a cross-sectional view of a metallic-composite joint is illustrated in accordance with an exemplary embodiment. Metallic-composite joint 400 is a physical implementation of metal-composite joint 210 of Figure 2. Metallic-composite joint 400 comprises a metallic structural component 402 and a composite material 404. Metallic structural component 402 comprises a first metallic structural component 406 and a second metallic structural component 408.

[0060] Two metallic structural components, first metallic structural component 406 and second metallic structural component 408, form a portion of a first surface 416 and a portion of a second surface 418 of metal-composite joint 400. A segmented set of composite plies 410 is between the two metallic structural components and provides an escape path 411 for volatiles between the two metallic structural components. In this illustrative example, volatiles can escape metal-composite joint 400 by traveling between layers along segmented set of composite plies 410.

[0061] In this illustrative example, segmented-set of composite plies 410 is adhered to two metal structural components, first metal structural component 406 and second metal structural component 408. In this illustrative example, segmented-set of composite plies 410 is bonded to stepped surface 420 of first metal structural component 406 and stepped surface 424 of second metal structural component 408. In this illustrative example, structural adhesive 428 adheres segmented-set of composite plies 410 to each of stepped surface 420 and stepped surface 424.

[0062] Sub-set of composite plies 410 may comprise any desired quantity of composite plies, hi some illustrative examples, sub-set of composite plies 410 may comprise a stack of six composite plies.

[0063] The first metal structural component 406 comprises a stepped surface 420 and a flat surface 422. The second metal structural component 408 comprises a stepped surface 424 and a flat surface 426. The first set of composite plies 412 comprises a mating surface complementary to the first metal structural component 406 of the two metal structural components. The second set of composite plies 414 comprises a mating surface complementary to the second metal structural component 408 of the two metal structural components. The first set of composite plies 412 is complementary to the first metal structural component 406. The second set of composite plies 414 is complementary to the second metal structural component 408.

[0064] The first set of composite plies 412 includes a first ply stack 430, a second ply stack 432, a third ply stack 434, and a fourth ply stack 436. Each stack of the first set of composite plies includes any desired amount of plies. In some illustrative examples, each stack of plies includes six plies. The second set of composite plies 414 includes a fifth ply stack 438, a sixth ply stack 440, a seventh ply stack 442, and an eighth ply stack 444.

[0065] In some illustrative examples, a manufacturable gap may exist between first set of composite plies 412 and stepped surface 420 of first metal structural component 406. In some illustrative examples, a manufacturable gap may exist between second set of composite plies 414 and stepped surface 424 of second metal structural component 408. Volatiles from the gap may vent through escape path 411 during processing of metal-composite joint 400.

[0066] In this illustrative example, two metallic structural components, first metallic structural component 406 and second metallic structural component 408, are symmetrical about a center 448 of metal-composite joint 400 through thickness 446. In this illustrative example, flat surface 422 faces away from flat surface 426 around center 448 of metal-composite joint 400 through thickness 446. In this illustrative example, stepped surface 420 faces stepped surface 424 around center 448 of metal-composite joint 400 through thickness 446. In this illustrative example, flat surface 422 forms a portion of first surface 416. In this illustrative example, the shortest composite ply of first set of composite plies 412 forms a portion of first surface 416. In this illustrative example, the shortest composite ply of second set of composite plies 414 forms a portion of second surface 418. In this illustrative example, the longest portions of stepped surface 420 and stepped surface 424 are near center 448, so that the two metal structural components appear to "extend into" the composite material.

[0067] A split set of composite plies 410 extends between a first set of composite plies 412 and a second set of composite plies 414. The first set of composite plies 412 forms a lap joint with a stepped surface 420 of the first metal structural component 406. The second set of composite plies 414 forms a lap joint with a stepped surface 424 of the second metal structural component 408.

[0068] In this illustrative example, structural adhesive 428 covers the faying surfaces of two metal structural components, first metal structural component 406 and second metal structural component 408, having first set of composite plies 412 and second set of composite plies 414. In this illustrative example, structural adhesive 428 bonds first set of composite plies 412 to first metal structural component 406. In this illustrative example, structural adhesive 428 bonds second set of composite plies 414 to second metal structural component 408. As shown, structural adhesive 428 extends partially between fourth ply stack 436 and segmented set of composite plies 410. As shown, structural adhesive 428 extends partially between segmented set of composite plies 410 and fifth ply stack 438.

[0069] In some illustrative examples, the two metal structural components, first metal structural component 406 and second metal structural component 408, comprise titanium.

[0070] In some illustrative examples, metal-composite joint 400 may be a component of an aircraft wing, hi some illustrative examples, metal-composite joint 400 may connect an aircraft wing to the body of the aircraft.

[0071] As shown, the two metal structural components include a first metal structural component 406 having a stepped surface 420 and a flat surface 422, and a second metal structural component 408 having a stepped surface 424 and a flat surface 426. In this illustrative example, the flat surfaces of the first metal structural component 406 and the second metal structural component 408 are on the interior side of the platform. In this illustrative example, the stepped surfaces of the first metal structural component 406 and the second metal structural component 408 form part of the surface of the platform.

[0072] Metal-composite joint 400 is a non-limiting example. In this illustrative example, metal-composite joint 400 is symmetrical about center 448 through thickness 446. In other illustrative examples, metal-composite joint 400 may be asymmetrical. While four metal structural components are shown, the metal-composite joint of the illustrative example can have any desired amount of metal structural components. Additionally, while metal structural components 402 each extend an equal distance into the composite material, in other illustrative examples, at least one metal structural component may be a different size, shape, or other configuration.

[0073] 5, a cross-sectional view of a metal-composite joint is illustrated in accordance with an exemplary embodiment. Metal-composite joint 500 is a physical implementation of metal-composite joint 210. Metal-composite joint 500 comprises metal structural components 502 separated by sets of segmented composite plies. Metal structural components 502 comprise first metal structural component 504, second metal structural component 506, third metal structural component 508, and fourth metal structural component 510. In this illustrative example, the sets of segmented composite plies include segmented set of composite plies 512, segmented set of composite plies 514, and segmented set of composite plies 516.

[0074] In this illustrative example, metal-composite joint 500 further comprises first set of composite plies 518, second set of composite plies 520, third set of composite plies 522, and fourth set of composite plies 524. In this illustrative example, metal-composite joint 500 comprises first surface 526 and second surface 528. Moving through thickness 530 from first surface 526 to second surface 528 of metal-composite joint 500, each of metal structural component 502, first set of composite plies 518, segmented set of composite plies 512, second set of composite plies 520, segmented set of composite plies 514, third set of composite plies 522, segmented set of composite plies 516, and fourth set of composite plies 524.

[0075] In this illustrative example, each of the sets of segmented composite plies provides an escape path for volatiles from metal-composite joint 500. Segmented set of composite plies 512 provides escape path 532 for the migration of volatiles. Segmented set of composite plies 514 provides escape path 534 for the migration of volatiles. Segmented set of composite plies 516 provides escape path 536 for the migration of volatiles.

[0076] By migrating along escape path 532, escape path 534, or escape path 536, volatiles migrate between layers through structure 538 having metal-composite joint 500. By providing composite ply segmented set 512, composite ply segmented set 514, and composite ply segmented set 516, structure 538 has improved venting capabilities. Metal-composite joint 500 having composite ply segmented set 512, composite ply segmented set 514, and composite ply segmented set 516 has lower porosity than a structure having a single titanium component extending through thickness 530 without a segmented composite ply. Metal-composite joint 500 having composite ply segmented set 512, composite ply segmented set 514, and composite ply segmented set 516 can have a lower fabrication time without repeated heating for venting. Metal-composite joint 500 having split set of composite plies 512, split set of composite plies 514, and split set of composite plies 516 may have improved quality due to the presence of the split composite ply sets.

[0077] Metal-composite joint 500 is a non-limiting example. In this illustrative example, metal-composite joint 500 is symmetrical about the center of metal-composite joint 500 through thickness 530. In other illustrative examples, metal-composite joint 500 may be asymmetrical. While four metal structural components are shown, the metal-composite joint of the illustrative example can have any desired amount of metal structural components. Additionally, while metal structural components 502 each extend an equal distance into the composite material, in other illustrative examples, at least one metal structural component may be of a different size, shape, or other configuration.

[0078] Referring now to Figure 6, an illustration of a flowchart of a method for forming a structural metallic composite joint is depicted in accordance with an illustrative embodiment. Method 600 may be used to form the metallic composite joint of aircraft 100 in Figure 1. Method 600 may be used to form metallic composite joint 210 in Figure 2. Method 600 may be used to form metallic composite joint 300 in Figure 3. Method 600 may be used to form metallic composite joint 400 in Figure 4. Method 600 may be used to form metallic composite joint 500 in Figure 5.

[0079] The method 600 places a segmented set of composite plies on a first metal structural component (operation 602). The method 600 places a second metal structural component on the segmented set of composite plies (operation 604). The method 600 bonds the first metal structural component and the second metal structural component to the segmented set of composite plies (operation 606). The method 600 then ends.

[0080] In some illustrative examples, method 600 bonds faying surfaces of the first set of composite plies to the first metal structural component (operation 607). In some illustrative examples, the first set of composite plies form a stepped joint with the first metal structural component. In some illustrative examples, the first set of composite plies form a portion of a surface of a metal-composite joint of the structure.

[0081] In some illustrative examples, the method 600 bonds the faying surfaces of the second set of composite plies to the second metal structural component (operation 608). In some illustrative examples, the second set of composite plies form a stepped joint with the second metal structural component. In some illustrative examples, the second set of composite plies form a portion of a surface of a metal-composite joint of the structure.

[0082] In some illustrative examples, method 600 bonds the first set of composite plies and the second set of composite plies to the sub-set of composite plies (Operation 610). In some illustrative examples, the first set of composite plies and the second set of composite plies are co-bonded to the sub-set of composite plies. In some illustrative examples, an adhesive extends partially between the first set of composite plies and the sub-set of composite plies. In some illustrative examples, an adhesive extends partially between the second set of composite plies and the sub-set of composite plies.

[0083] In some illustrative examples, method 600 applies an adhesive to at least one of a first metallic structural component, a second metallic structural component, or a segmented set of composite plies (operation 611). In some illustrative examples, the adhesive is positioned between the first metallic structural component and the segmented set of composite plies. In some illustrative examples, the adhesive is positioned between the second metallic structural component and the segmented set of composite plies. In some illustrative examples, the adhesive is positioned between the first metallic structural component and the first set of composite plies. In some illustrative examples, the adhesive is positioned between the second metallic structural component and the second set of composite plies.

[0084] In some illustrative examples, bonding the first metallic structural component and the second metallic structural component to the segmented-set of composite plies includes bonding a stepped surface of the first metallic structural component and a stepped surface of the second metallic structural component to the segmented-set of composite plies to form a structure having a first surface comprising a flat surface of the first metallic structural component and a second surface comprising a flat surface of the second metallic structural component (Operation 612). In some illustrative examples, the longest surface of the first metallic structural component in the length of the structure forms a portion of the first surface. In some illustrative examples, the longest surface of the second metallic structural component in the length of the structure forms a portion of the second surface. In these illustrative examples, the composite material may appear to extend between the metallic structural components.

[0085] In some illustrative examples, bonding the first metallic structural component and the second metallic structural component to the segmented-set of composite plies includes bonding a flat surface of the first metallic structural component and a flat surface of the second metallic structural component to the segmented-set of composite plies to form a structure having a first surface comprising a stepped surface of the first metallic structural component and a second surface comprising a stepped surface of the second metallic structural component (Operation 614). In some illustrative examples, the longest surface of the first metallic structural component in the length of the structure is at the center of the metal-composite joint. In some illustrative examples, the longest surface of the second metallic structural component in the length of the structure is at the center of the metal-composite joint. In these illustrative examples, the metallic structural components may appear to extend into the composite material.

[0086] Referring now to Figure 7, an illustration of a flowchart of a method for venting volatile materials from a metal-composite joint in a structure is depicted in accordance with an illustrative embodiment. Method 700 may be used to vent volatile materials from a metal-composite joint in aircraft 100 of Figure 1. Method 700 may be used to form metal-composite joint 210 of Figure 2. Method 700 may be used to form metal-composite joint 300 of Figure 3. Method 700 may be used to form metal-composite joint 400 of Figure 4. Method 700 may be used to form metal-composite joint 500 of Figure 5.

[0087] The method 700 lays up a metal-composite joint having a split-set of composite plies between a first metal structural component and a second metal structural component (operation 702). The method 700 bonds the first metal structural component and the second metal structural component to the split-set of composite plies (operation 704). The method 700 evacuates volatiles along the split-set of composite plies and between the first metal structural component and the second metal structural component during bonding (operation 706). Thereafter, the method 700 ends.

[0088] In some illustrative examples, venting the volatile material along the divided sets of composite plies includes moving the volatile material along at least one of a length of the structure or a width of the structure (Operation 708). By moving along the length or width of the structure, the volatile material moves between layers within the structure. By moving along the length or width of the structure, the volatile material does not move through a thickness within the structure.

[0089] In some illustrative examples, the first metallic structural component, the segmented set of composite plies, and the second metallic structural component are joined through the thickness of the structure (operation 710). In these illustrative examples, the first metallic structural component, the segmented set of composite plies, and the second metallic structural component each encounter as they move through the metal-composite joint through the thickness.

[0090] In some illustrative examples, the method 700 bonds faying surfaces of the first set of composite plies to the first metal structural component (operation 712). In some illustrative examples, the first set of composite plies form a stepped joint with the first metal structural component. In some illustrative examples, the first set of composite plies form a portion of a surface of a metal-composite joint of the structure.

[0091] In some illustrative examples, the method 700 bonds the faying surfaces of the second set of composite plies to the second metal structural component (operation 714). In some illustrative examples, the second set of composite plies form a stepped joint with the second metal structural component. In some illustrative examples, the second set of composite plies form a portion of a surface of a metal-composite joint of the structure.

[0092] In some illustrative examples, method 700 applies an adhesive to at least one of the first metallic structural component, the second metallic structural component, or the segmented set of composite plies (operation 716). In some illustrative examples, the adhesive is positioned between the first metallic structural component and the segmented set of composite plies. In some illustrative examples, the adhesive is positioned between the second metallic structural component and the segmented set of composite plies. In some illustrative examples, the adhesive is positioned between the first metallic structural component and the first set of composite plies. In some illustrative examples, the adhesive is positioned between the second metallic structural component and the second set of composite plies.

[0093] As used herein, the phrase "at least one of," when used in conjunction with a list of items, means that various combinations of one or more of the listed items may be used, and that 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 be present. In other examples, "at least one of" may be, for example, but is not limited to, two item A, one item B, and ten item C, or four item B and seven item C, or any other suitable combination. An item may be a specific object, thing, or category. In other words, at least one of means that any combination and number of items may be used from the list, but not all of the items in the list are required.

[0094] As used herein, "plurality," when used in reference to an item, means one or more items.

[0095] The flowcharts and block diagrams in the different depicted embodiments illustrate the architecture, functionality, and operation of some possible implementations of apparatuses and methods in the illustrative embodiments. In this regard, each block in the flowcharts or block diagrams may represent at least one of a module, a segment, a function, or a portion of an operation or step.

[0096] In some alternative implementations of the exemplary embodiments, one or more 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 may even be executed in the reverse order, depending on the functionality involved. Also, other blocks may be added in addition to the illustrated blocks in a flowchart or block diagram. Some blocks may be optional. For example, operations 607 through 614 may be optional. As another example, operations 708 through 716 may be optional.

[0097] An exemplary embodiment of the present disclosure may be described in the context of aircraft manufacturing and service method 800 shown in Figure 8 and aircraft 900 shown in Figure 9. Referring initially to Figure 8, an illustration of an aircraft manufacturing and service method in block diagram form is depicted in accordance with an exemplary embodiment. During pre-production, aircraft manufacturing and service method 800 may include specification and design 802 and material procurement 804 of aircraft 900 in Figure 8.

[0098] During production, component and subassembly manufacturing 806 and system integration 808 of aircraft 900 occurs. Aircraft 900 may then undergo certification and delivery 810 to enter service 812. While in service 812 by a customer, aircraft 900 is scheduled for routine maintenance and service 814, which may include modification, reconfiguration, refurbishment, or other maintenance and service.

[0099] Each of the processes in aircraft manufacturing and service method 800 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 vendors, subcontractors, and suppliers; an operator may be an airline, a leasing company, the military, a service provider, etc.

[0100] Referring now to Figure 8, an illustration of an aircraft in block diagram form is depicted in which an illustrative embodiment may be implemented. In this example, aircraft 900 is produced by aircraft manufacturing and service method 800 in Figure 8 and may include an airframe 902 having multiple systems 904 and an interior 906. Example systems 904 include one or more of a propulsion system 908, an electrical system 910, a hydraulic system 912, and an environmental system 914. Any number of other systems may also be included.

[0101] Apparatus and methods embodied herein may be used during at least one of the stages of aircraft manufacturing and service method 800. One or more illustrative embodiments may be manufactured or used during at least one of component and subassembly manufacturing 806, system integration 808, in-service 812, or maintenance and service 814 in Figure 8.

[0102] An illustrative example shows a metal-composite joint having multiple metal structural components. Splitting the titanium into two or more components provides improved part quality and manufacturability. The composite ply can be more easily positioned between two titanium components than inserted into a recess in a single titanium component.

[0103] The illustrative examples enable weight savings to aircraft wing designs. The illustrative examples provide advantages in quality and damage tolerance.

[0104] In the illustrative example, volatiles and air travel along the partitions between titanium components. The titanium is partitioned through its thickness with an additional layer of composite between them to aid in the removal of volatiles during fabrication. The illustrative example can provide improved in-service damage tolerance. The illustrative example can improve crack propagation prevention.

[0105] The description of different exemplary embodiments is presented for purposes of illustration and description and is not intended to be exhaustive or limited to the disclosed forms of the embodiments. Many modifications and variations will be apparent to those skilled in the art. Furthermore, different exemplary embodiments may provide different features compared to other exemplary embodiments. The selected one or more embodiments have been chosen and described to best explain the principles and practical applications of the embodiments, and to enable those skilled in the art to understand the present disclosure for various embodiments with various modifications suitable for the particular use contemplated.

[0106] [Additional note 1] A metal-composite joint (210, 300, 400, 500) for a platform (202), comprising: two metal structural components (212, 214, 302, 402, 502) forming a portion of a first surface (226, 316, 416, 526) and a portion of a second surface (228, 318, 418, 528) of said metal-composite joint (210, 300, 400, 500); a split set (222, 310, 410, 512, 514, 516) of composite plies between two of said metal structural components (212, 214, 302, 402, 502), said split set of composite plies providing an escape path (224, 311, 411, 532, 534, 536) for volatile material (223) between said two metal structural components (212, 214, 302, 402, 502); A metal-composite joint comprising: [Additional note 2] 2. The metal-composite joint of claim 1, wherein the segmented set of composite plies (222, 310, 410, 512, 514, 516) is bonded to two of the metal structural components (212, 214, 302, 402, 502). [Additional note 3] a third metal structural component (506 or 508) between two of the metal structural components (212, 214, 302, 402, 502), wherein the segmented set of composite plies (222, 310, 410, 512, 516) is bonded to one of the two metal structural components (212, 214, 302, 402, 502) and to the third metal structural component (506 or 508); The metal-composite joint according to claim 1, further comprising: [Additional note 4] a first set of composite plies (230, 312, 412, 518) having a faying surface with a first metal structural component (212, 306, 406, 504) of the two metal structural components (212, 214, 302, 402, 502); a second set of composite plies (232, 314, 414, 520) having a faying surface with a second metal structural component (214, 308, 408, 506) of the two metal structural components (212, 214, 302, 402, 502); The metal-composite joint according to claim 1, further comprising: [Additional note 5] the first set of composite plies (230, 312, 412, 518) are complementary to the first metal structural component (212, 306, 406, 504); 5. The metal-composite joint of claim 4, wherein the second set of composite plies (232, 314, 414, 520) is complementary to the second metal structural component (214, 308, 408, 506). [Additional note 6] 2. The metal-composite joint of claim 1, wherein the two metal structural components (212, 214, 302, 402, 502) are symmetrical about a center (348, 448) of the metal-composite joint (210, 300, 400, 500) through a thickness (246, 346, 446, 530). [Additional note 7] 5. The metal-composite joint of claim 4, wherein the split set of composite plies (222, 310, 410, 512, 514, 516) extends between the first set of composite plies (230, 312, 412, 518) and the second set of composite plies (232, 314, 414, 520). [Additional note 8] 5. The metal-composite joint of claim 4, wherein the first set of composite plies (230, 312, 412, 518) forms a lap joint (242) with a stepped surface (216, 320, 420) of the first metal structural component (212, 306, 406, 504). [Additional note 9] 5. The metal-composite joint of claim 4, wherein the second set of composite plies (232, 314, 414, 520) forms a lap joint (243) with a stepped surface (221, 324, 424) of the second metal structural component (214, 308, 408). [Additional Note 10] 5. The metal-composite joint of claim 4, wherein a structural adhesive (244, 328, 428) covers the joining surfaces of two of the metal structural components (212, 214, 302, 402, 502) having the first set of composite plies (230, 312, 412, 518) and the second set of composite plies (232, 314, 414, 520). [Additional Note 11] 2. The metal-composite joint according to claim 1, wherein the two metal structural components (212, 214, 302, 402, 502) comprise titanium (213, 215). [Additional Note 12] 2. The metal-composite joint of claim 1, wherein the platform (202) is a wing (102, 104, 206) of an aircraft (100, 204, 900). [Additional Note 13] The two metal structural components (212, 214, 302, 402, 502) are a first metal structural component (212, 406) having a stepped surface (216, 420) and a flat surface (218, 422); a second metal structural component (214, 408) having a stepped surface (221, 424) and a flat surface (220, 426), wherein the flat surfaces (218, 220, 422, 426) of the first metal structural component (212, 406) and the second metal structural component (214, 408) form a surface (226, 228, 416, 418) of the platform (202); The metal-composite joint according to claim 1, comprising: [Additional Note 14] The two metal structural components (212, 214, 302) are a first metal structural component (212, 306) having a stepped surface (216, 320) and a flat surface (218, 322); a second metal structural component (214, 308) having a stepped surface (221, 324) and a flat surface (220, 326), wherein the segmented set of composite plies (222, 310) is bonded to the flat surfaces (218, 220, 322, 326) of the first metal structural component (212, 306) and the second metal structural component (214, 308); The metal-composite joint according to claim 1, comprising: [Additional Note 15] A metal-composite joint (210, 300, 400, 500) for a platform (202), comprising: a first metal structural component (212, 306, 406, 504) having a stepped surface (216, 320, 420) and a flat surface (218, 322, 422); a first set of composite plies (230, 312, 412, 518) having a mating surface complementary to the stepped surface (216, 320, 420) of the first metal structural component (212, 306, 406, 504); a second metal structural component (214, 308, 408, 506) having a stepped surface (221, 324, 424) and a flat surface (220, 326, 426); a second set of composite plies (232, 314, 414, 520) having a mating surface complementary to the stepped surface (216, 221, 320, 324, 420, 424) of the second metal structural component (214, 308, 408, 506); a segmented set of composite plies (222, 310, 410, 512, 514, 516) between the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506), the segmented set of composite plies providing an escape path (224, 311, 411, 532, 534, 536) for volatile materials (223) between the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506); A metal-composite joint comprising: [Additional Note 16] 16. The metal-composite joint of claim 15, wherein the segmented set of composite plies (222, 310) extends between and is bonded to the flat surfaces (218, 220, 322, 326) of the first metal structural component (212, 306) and the second metal structural component (214, 308). [Additional Note 17] 16. The metal-composite joint of claim 15, wherein the segmented sets of composite plies (222, 310, 410, 512, 514, 516) extend between and are bonded to the stepped surfaces (216, 221, 320, 324, 420, 424) of the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506). [Additional Note 18] 16. The metal-composite joint of claim 15, wherein the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506) comprise titanium (213, 215). [Additional Note 19] Item 16. The metal-composite joint according to item 15, wherein the platform (202) is a wing (102, 104, 206) of an aircraft (100, 204, 900). [Additional Note 20] A method (600) of forming a metal-composite joint (210, 300, 400, 500) in a structure (538), comprising: laying (602) a segmented set of composite plies (222, 310, 410, 512, 514, 516) on a first metal structural component (212, 306, 406, 504); placing (604) a second metal structural component (214, 308, 408, 506) on the segmented set of composite plies (222, 310, 410, 512, 514, 516); bonding (606) the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506) to the segmented set of composite plies (222, 310, 410, 512, 514, 516); A method comprising: [Additional Note 21] bonding (607) faying surfaces of a first set of composite plies (230, 312, 412, 518) to the first metal structural component (212, 306, 406, 504); bonding (608) the faying surfaces of the second set of composite plies (232, 314, 414, 520) to the second metal structural component (214, 308, 408, 506); 21. The method according to claim 20, further comprising: [Additional Note 22] joining (610) the first set (230, 312, 412, 518) of composite plies and the second set (232, 314, 414, 520) of composite plies to the split set (222, 310, 410, 512, 514, 516) of composite plies; 22. The method according to claim 21, further comprising: [Additional note 23] 21. The method of claim 20, wherein the step of bonding the first metal structural component (212, 406) and the second metal structural component (214, 408) to the segmented set of composite plies (222, 410) includes a step (612) of bonding a stepped surface (216, 420) of the first metal structural component (212, 406) and a stepped surface (221, 424) of the second metal structural component (214, 408) to the segmented set of composite plies (222, 410) to form a structure having a first surface (226, 416) comprising a flat surface (218, 422) of the first metal structural component (212, 406) and a second surface (228, 418) comprising a flat surface (220, 426) of the second metal structural component (214, 408). [Additional note 24] 21. The method of claim 20, wherein the step of bonding the first metal structural component (212, 306) and the second metal structural component (214, 308) to the segmented set of composite plies (222, 310) includes a step (614) of bonding a flat surface (218, 322) of the first metal structural component (212, 306) and a flat surface (220, 326) of the second metal structural component (214, 308) to the segmented set of composite plies (222, 310) to form a structure having a first surface (226, 316) comprising a stepped surface (216, 320) of the first metal structural component (212, 306) and a second surface (228, 318) comprising a stepped surface (221, 324) of the second metal structural component (214, 308). [Additional note 25] applying (611) an adhesive (244, 328, 428) to at least one of the first metal structural component (212, 306, 406, 504), the second metal structural component (214, 308, 408, 506), or the segmented set of composite plies (222, 310, 410, 512, 514, 516); 21. The method according to claim 20, further comprising: [Additional note 26] A method (700) for removing volatile materials (223) from a metal-composite joint (210, 300, 400, 500) of a structure (538), comprising: laying up (702) the metal-composite joint (210, 300, 400, 500) having a split set of composite plies (222, 310, 410, 512, 514, 516) between a first metal structural component (212, 306, 406, 504) and a second metal structural component (214, 308, 408, 506); bonding (704) the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506) to the segmented set of composite plies (222, 310, 410, 512, 514, 516); evacuating (706) volatile materials (223) along the composite ply segment sets (222, 310, 410, 512, 514, 516) and between the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506) during bonding; A method comprising: [Additional note 27] 27. The method of claim 26, wherein the step of discharging the volatile material (223) along the divided sets (222, 310, 410, 512, 514, 516) of composite plies includes a step (708) of moving the volatile material (223) along at least one of a length of the structure (538) and a width of the structure (538). [Additional note 28] 28. The method of claim 27, wherein the first metal structural component (212, 306, 406, 504), the composite ply segment set (222, 310, 410, 512, 514, 516), and the second metal structural component (214, 308, 408, 506) are joined (710) through a thickness (246, 346, 446, 530) of the structure (538). [Additional note 29] bonding (712) faying surfaces of a first set of composite plies (230, 312, 412, 518) to the first metal structural component (212, 306, 406, 504); bonding (714) the faying surfaces of the second set of composite plies (232, 314, 414, 520) to the second metal structural component (214, 308, 408, 506); 27. The method according to claim 26, further comprising: [Additional note 30] applying (716) an adhesive (244, 328, 428) to at least one of the first metal structural component (212, 306, 406, 504), the second metal structural component (214, 308, 408, 506), or the segmented set of composite plies (222, 310, 410, 512, 514, 516); 27. The method according to claim 26, further comprising: [Explanation of symbols]

[0107] 100 aircraft, 102 wing, 104 wing, 106 body, 108 engine, 110 engine, 112 tail section, 114 horizontal stabilizer, 116 horizontal stabilizer, 118 vertical stabilizer, 200 manufacturing environment, 202 platform, 204 aircraft, 206 wing, 208 body, 210 metal-composite joint, 212 first metal structural component, 213 titanium, 214 second metal structural component, 215 titanium, 216 stepped surface, 218 flat surface, 220 flat surface, 221 stepped surface, 222 split set of composite plies, 223 volatile material, 224 escape path, 226 first surface, 228 second surface, 230 first set of composite plies, 232 second set of composite plies, 234 First ply stack, 235, length, 236, second ply stack, 237, length, 238, third ply stack, 239, length, 240, fourth ply stack, 241, length, 242, lap joint, 243, lap joint, 244, structural adhesive, 246, thickness, 248, bonding surface, 250, bonding surface, 300, metal-composite joint, 302, metal structural component, 304, composite material, 306, first metal structural component, 308, second metal structural component, 310, split set of composite plies, 311, relief path, 312, first set of composite plies, 314, second set of composite plies, 316, first surface, 318, second surface, 320, stepped surface, 322, flat surface, 324, stepped surface, 326, flat surface, 328, structural adhesive, 330, first ply stack, 332 Second ply stack, 334 Third ply stack, 336 Fourth ply stack, 338 Fifth ply stack, 340 Sixth ply stack, 342 Seventh ply stack, 344 Eighth ply stack, 346 Thickness, 348 Center, 400 Metal-composite joint, 402 Metal structural component, 404 Composite material, 406 First metal structural component, 408 Second metal structural component, 410 Split set of composite plies, 411 Escape path, 412 First set of composite plies, 414 Second set of composite plies, 416 First surface, 418 Second surface, 420 Stepped surface, 422 Flat surface, 424 Stepped surface, 426 Flat surface, 428 Structural adhesive, 430 First ply stack, 432Second ply stack, 434 Third ply stack, 436 Fourth ply stack, 438 Fifth ply stack, 440 Sixth ply stack, 442 Seventh ply stack, 444 Eighth ply stack, 446 Thickness, 448 Center, 500 Metal-composite joint, 502 Metal structural component, 504 First metal structural component, 506 Second metal structural component, 508 Third metal structural component, 510 Fourth metal structural component, 512 Split set of composite plies, 514 Split set of composite plies, 516 Split set of composite plies, 518 First set of composite plies, 520 Second set of composite plies, 522 Third set of composite plies, 524 Fourth set of composite plies, 526 First surface, 528 Second surface, 530 Thickness, 532 Relief path, 534 Relief path, 536 Relief path, 538 Structure, 600 Method, 602 Operations / Steps, 604 Operations / Steps, 606 Operations / Steps, 607 Operations / Steps, 608 Operations / Steps, 610 Operations / Steps, 611 Operations / Steps, 612 Operations / Steps, 614 Operations / Steps, 700 Method, 702 Operations / Steps, 704 Operations / Steps, 706 Operations / Steps, 708 Operations / Steps, 710 Operations / Steps, 712 Operations / Steps, 714 Operations / Steps, 716 Operations / Steps, 800 Aircraft Manufacturing and Maintenance Methods, 802 Specification and Design, 804 Materials Procurement, 806 Component and Subassembly Manufacturing, 808 System Integration, 810 Certification and Delivery, 812 In-Service, 814 Maintenance and Service, 900 Aircraft, 902 Airframe, 904 Systems, 906 Interior, 908 Propulsion system, 910 Electrical system, 912 Hydraulic system, 914 Environmental system

Claims

1. A metal-composite joint (210, 300, 400, 500) for a platform (202), comprising: two metallic structural components (212, 214, 302, 402, 502) forming a portion of a first surface (226, 316, 416, 526) and a portion of a second surface (228, 318, 418, 528) of said metal-composite joint (210, 300, 400, 500); a split set of composite plies (222, 310, 410, 512, 514, 516) between two of said metal structural components (212, 214, 302, 402, 502), said split set of composite plies providing an escape path (224, 311, 411, 532, 534, 536) for volatile materials (223) between said two metal structural components (212, 214, 302, 402, 502); A metal-composite joint comprising:

2. The metal-composite joint of claim 1, wherein the split set of composite plies (222, 310, 410, 512, 514, 516) is bonded to two of the metal structural components (212, 214, 302, 402, 502).

3. a third metal structural component (506 or 508) between two of the metal structural components (212, 214, 302, 402, 502), wherein the split set of composite plies (222, 310, 410, 512, 516) is bonded to one of the two metal structural components (212, 214, 302, 402, 502) and to the third metal structural component (506 or 508); The metal-composite joint of claim 1 further comprising:

4. a first set of composite plies (230, 312, 412, 518) having a faying surface with a first metal structural component (212, 306, 406, 504) of the two metal structural components (212, 214, 302, 402, 502); a second set of composite plies (232, 314, 414, 520) having a faying surface with a second metal structural component (214, 308, 408, 506) of the two metal structural components (212, 214, 302, 402, 502); The metal-composite joint of claim 1 further comprising:

5. the first set of composite plies (230, 312, 412, 518) is complementary to the first metal structural component (212, 306, 406, 504); The metal-composite joint of claim 4, wherein the second set of composite plies (232, 314, 414, 520) is complementary to the second metal structural component (214, 308, 408, 506).

6. 2. The metal-composite joint of claim 1, wherein the two metal structural components are symmetrical about a center of the metal-composite joint through a thickness.

7. The metal-composite joint of claim 4, wherein the split set of composite plies (222, 310, 410, 512, 514, 516) extends between the first set of composite plies (230, 312, 412, 518) and the second set of composite plies (232, 314, 414, 520).

8. 5. The metal-composite joint of claim 4, wherein the first set of composite plies forms a lap joint with a stepped surface of the first metal structural component.

9. 5. The metal-composite joint of claim 4, wherein the second set of composite plies forms a lap joint with a stepped surface of the second metal structural component.

10. 5. The metal-composite joint of claim 4, wherein a structural adhesive covers a joining surface of two said metal structural components having said first set of composite plies and said second set of composite plies.

11. The metal-composite joint of claim 1, wherein two of said metallic structural components (212, 214, 302, 402, 502) comprise titanium (213, 215).

12. The metal-composite joint of any preceding claim, wherein the platform (202) is a wing (102, 104, 206) of an aircraft (100, 204, 900).

13. The two metal structural components (212, 214, 302, 402, 502) are a first metal structural component (212, 406) having a stepped surface (216, 420) and a flat surface (218, 422); a second metal structural component (214, 408) having a stepped surface (221, 424) and a flat surface (220, 426), wherein the flat surfaces (218, 220, 422, 426) of the first metal structural component (212, 406) and the second metal structural component (214, 408) form a surface (226, 228, 416, 418) of the platform (202); The metal-composite joint of claim 1 , comprising:

14. The two metal structural components (212, 214, 302) are a first metal structural component (212, 306) having a stepped surface (216, 320) and a flat surface (218, 322); a second metal structural component (214, 308) having a stepped surface (221, 324) and a flat surface (220, 326), wherein the segmented set of composite plies (222, 310) is bonded to the flat surfaces (218, 220, 322, 326) of the first metal structural component (212, 306) and the second metal structural component (214, 308); The metal-composite joint of claim 1 , comprising:

15. A metal-composite joint (210, 300, 400, 500) for a platform (202), comprising: a first metal structural component (212, 306, 406, 504) having a stepped surface (216, 320, 420) and a flat surface (218, 322, 422); a first set of composite plies (230, 312, 412, 518) having a joining surface complementary to the stepped surface (216, 320, 420) of the first metal structural component (212, 306, 406, 504); a second metal structural component (214, 308, 408, 506) having a stepped surface (221, 324, 424) and a flat surface (220, 326, 426); a second set of composite plies (232, 314, 414, 520) having joining surfaces complementary to the stepped surfaces (216, 221, 320, 324, 420, 424) of the second metal structural component (214, 308, 408, 506); a segmented set of composite plies (222, 310, 410, 512, 514, 516) between the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506), the segmented set of composite plies providing an escape path (224, 311, 411, 532, 534, 536) for volatile materials (223) between the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506); A metal-composite joint comprising:

16. 16. The metal-composite joint of claim 15, wherein the segmented set of composite plies extends between and is bonded to the planar surfaces of the first and second metal structural components.

17. 16. The metal-composite joint of claim 15, wherein the segmented set of composite plies extends between and is bonded to the stepped surfaces of the first and second metal structural components.

18. The metal-composite joint of claim 15, wherein the first metallic structural component (212, 306, 406, 504) and the second metallic structural component (214, 308, 408, 506) comprise titanium (213, 215).

19. The metal-composite joint of claim 15, wherein the platform (202) is a wing (102, 104, 206) of an aircraft (100, 204, 900).

20. A method (600) of forming a metal-composite joint (210, 300, 400, 500) in a structure (538), comprising: Laying (602) a segmented set of composite plies (222, 310, 410, 512, 514, 516) on a first metal structural component (212, 306, 406, 504); placing (604) a second metal structural component (214, 308, 408, 506) on the segmented set of composite plies (222, 310, 410, 512, 514, 516); bonding (606) the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506) to the segmented set of composite plies (222, 310, 410, 512, 514, 516); A method comprising:

21. A method (700) for removing volatile materials (223) from a metal-composite joint (210, 300, 400, 500) of a structure (538), comprising: laying up (702) the metal-composite joint (210, 300, 400, 500) having a split set of composite plies (222, 310, 410, 512, 514, 516) between a first metal structural component (212, 306, 406, 504) and a second metal structural component (214, 308, 408, 506); bonding (704) the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506) to the segmented set of composite plies (222, 310, 410, 512, 514, 516); evacuating (706) volatile materials (223) along the composite ply segment sets (222, 310, 410, 512, 514, 516) and between the first metal structural component (212, 306, 406, 504) and the second metal structural component (214, 308, 408, 506) during bonding; A method comprising:

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