Shear strap for aircraft wing

Abstract

This application relates to shear straps for aircraft wings. An example aircraft wing includes a skin, a composite shear strap, a spar base charge covering the skin, and a spar covering the spar base charge. The composite shear strap includes a shear strap web, a first shear strap flange extending from a first side of the shear strap web, a second shear strap flange extending from a second side of the shear strap web, and a first shear strap tab extending from an end of the first side of the shear strap web. The spar includes a spar web, a first spar flange extending from a first side of the spar web, and a second spar flange extending from a second side of the spar web. The first spar flange is stitched to the spar base charge and the skin and is integral with the spar base charge and the skin. In addition, the first shear strap flange is stitched to the first spar flange and is integral with the first spar flange.

Description

Technical Field

[0001] The present disclosure generally relates to aircraft wings and, more particularly, to assemblies for attaching ribs of an aircraft wing to a skin of the aircraft wing. Background Art

[0002] Due to the generally high strength-to-weight ratio inherent in composite materials, composite materials are increasingly used as substitutes for conventional materials such as aluminum and steel alloys in various structural components. For example, composite parts are currently used as parts of an aircraft. Composite materials generally include reinforcing fibers (referred to as plies) applied in layers and a network of resin that substantially wets the reinforcing fibers to form a tight contact between the resin and the reinforcing fibers.

[0003] Some aircraft wing designs incorporate composite structural components in the aircraft wing, such as ribs, spars, and stringers. The internal structure of an aircraft wing can include spars and stringers that extend along the length of the aircraft wing from the aircraft fuselage to the tip of the aircraft wing, and ribs that are oriented chordwise (i.e., from the leading edge of the aircraft wing to the trailing edge of the aircraft wing). The spars are located fore and aft of the wing box and are attached to the upper skin and the lower skin. The stringers can support the upper skin and the lower skin and shape the aircraft wing. The ribs support the upper skin and the lower skin. These ribs can be attached to the upper skin and the lower skin using components called shear ties. Due to the loads that the aircraft wing is subjected to during flight and on the ground, the ribs can be pushed away from or pulled away from the upper skin and the lower skin. Summary of the Invention

[0004] In one example, an assembly for attaching a rib of an aircraft wing to a skin of the aircraft wing is described. The assembly includes a composite shear tie, a stringer base stock covering the skin, and a stringer covering the stringer base stock. The composite shear tie has a shear tie web, a first shear tie flange extending from a first side of the shear tie web, a second shear tie flange extending from a second side of the shear tie web, and a first shear tie tab extending from an end of the first side of the shear tie web. The stringer includes a stringer web, a first stringer flange extending from a first side of the stringer web, and a second stringer flange extending from a second side of the stringer web. The first stringer flange is stitched to the stringer base stock and the skin and is integral with the stringer base stock and the skin. In addition, the first shear tie flange is stitched to the first stringer flange and is integral with the first stringer flange.

[0005] In another example, an aircraft wing is described. The aircraft wing includes a skin, a composite shear strap, a spar base charge covering the skin, and a spar covering the spar base charge. The composite shear strap includes a shear strap web, a first shear strap flange extending from a first side of the shear strap, a second shear strap flange extending from a second side of the shear strap web, and a first shear strap tab extending from an end of the first side of the shear strap web. The spar includes a spar web, a first spar flange extending from a first side of the spar web, and a second spar flange extending from a second side of the spar web. The first spar flange is stitched to the spar base charge and the skin and is integral with the spar base charge and the skin. In addition, the first shear strap flange is stitched to the first spar flange and is integral with the first spar flange.

[0006] In another example, a method of manufacturing and assembling an aircraft wing is described. The method includes integrating a spar base charge with a skin of an aircraft wing during a co-curing process. The method also includes integrating a spar with the spar base during the co-curing process, the spar including a spar web, a first spar flange extending from a first side of the spar web, and a second spar flange extending from a second side of the spar web. In addition, the method includes integrating a first shear strap flange of a composite shear strap with the first spar flange during the co-curing process. Additionally, the method includes fastening a composite rib to the shear strap web of the composite shear strap after the co-curing process.

[0007] The features, functions, and advantages that have been discussed can be implemented independently in various examples or can be combined in other examples. Further details thereof can be seen by referring to the following description and the drawings. Description of the Drawings

[0008] The novel features that are considered to be characteristics of the illustrative examples are set forth in the appended claims. However, the illustrative examples, as well as the preferred mode of use, further objectives, and its description, will be best understood by referring to the following detailed description of the illustrative examples of the present disclosure when read in conjunction with the drawings, in which:

[0009] Figure 1 An aircraft wing according to one example is shown.

[0010] Figure 2 A partial view of an assembly for connecting a rib of an aircraft wing to the skin of the aircraft wing according to one example is shown.

[0011] Figure 3 A partial view of an assembly for connecting a rib of an aircraft wing to the skin of the aircraft wing according to one example is shown.

[0012] Figure 4 Two different shear strap tab configurations according to one example are shown.

[0013] Figure 5 Shows a stitching technique according to an example.

[0014] Figure 6 Shows a partial view of an assembly for connecting a rib of an aircraft wing to the skin of the aircraft wing according to an example.

[0015] Figure 7 Shows Figure 6 a cross-sectional view of the assembly of

[0016] Figure 8 Shows a partial view of an assembly for connecting a rib of an aircraft wing to the skin of the aircraft wing according to an example.

[0017] Figure 9 Shows an additional stitching technique according to an example.

[0018] Figure 10 Shows two different flange edge configurations according to an example.

[0019] Figure 11 Shows a flowchart of a method according to an example.

[0020] Figure 12 Shows additional operations that can be performed in conjunction with Figure 11 the method shown. DETAILED DESCRIPTION

[0021] The disclosed examples will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, of the disclosed examples are shown. In fact, several different examples may be provided and should not be construed as limited to the examples set forth herein. Rather, these examples are provided so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those skilled in the art.

[0022] Described herein are assemblies for connecting ribs of an aircraft wing to the skin of the aircraft wing and methods for assembling an aircraft wing. Example assemblies include spar base stock, a spar covering the spar base stock, and a composite shear strap. The spar base stock is stitched to the skin and is integral with the skin. The skin can be an upper skin that is in compression during level flight or a lower skin that is in tension during level flight. Additionally, the spar includes a spar web, a first spar flange extending from a first side of the spar web, and a second spar flange extending from a second side of the spar web.

[0023] The composite shear strap includes a shear strap web, a first shear strap flange extending from a first side of the shear strap web, a second shear strap flange extending from a second side of the shear strap web, a first shear strap fin extending from one end of the first side of the shear strap web, and a second shear strap fin extending from the same end of the second side of the shear strap web. The first shear strap flange is stitched to and integral with the first spar flange, thereby increasing the amount of force required to pull out the composite shear strap. For example, at the intersection of the first shear strap flange and the first spar flange, the first shear strap flange and the first spar flange may be stitched together.

[0024] Stitching the first shear strap flange and the first spar flange together allows the first shear strap flange and the first spar flange to be integral during the co-curing process, so that the composite ribs can be effectively utilized to reduce weight. Instead of bolting to an aluminum rib, the stitched composite shear strap and spar can be co-cured together. The co-curing process may include inserting the composite shear strap and spar into an oven after stitching the first shear strap flange to the first spar flange, so that the composite shear strap and spar can be co-cured in the oven simultaneously. In the absence of stitching and co-curing, fasteners can be used instead to attach the first shear strap flange to the first spar flange and the skin. The co-curing process can make the aircraft wing less vulnerable to electromagnetic effects (such as those generated by lightning strikes), because stitching can eliminate the need to use fasteners between components that are co-cured and exposed to pulling forces. Bolting an aluminum rib with fasteners exposed to the outer mold line of the aircraft wing provides a direct path for current from a lightning strike to the wing fuel tank. Bolting the rib web to the shear strap with fasteners that are completely isolated from the outer mold line keeps the current in the skin and outside the fuel tank. Another advantage of the components described herein is that the components allow for the integration of lightweight rib webs attached in a vertical interface, thereby eliminating the use of gaskets used with aluminum ribs having a vertical interface with the skin.

[0025] The co-cured components of the aircraft wing can also reduce manufacturing time and cost. In addition, in some examples, other components of the aircraft wing can also be co-cured with the composite shear strap and spar (such as spar base loading and skin). Co-curing additional components with the composite shear strap and spar can further reduce manufacturing time and cost.

[0026] In some examples, the first shear strap fin can be stitched to and integral with the first side of the spar web, thereby stabilizing the spar web and further increasing the amount of force required to pull the composite shear strap away from the spar. In addition, the first shear strap fin can also overlap the first shear strap flange at the intersection between the first shear strap flange and the first spar flange. This overlap can further improve the pull-off load capacity of the shear strap.

[0027] Similarly, the portion of the first shear strap flange that does not intersect the first spar flange can be stitched to the skin and integrated with the skin, thereby strengthening the bond between the composite shear strap and the skin. For example, a portion of the first shear strap flange disposed between a spar and another spar can be stitched to the skin and integrated with the skin.

[0028] In addition, the assembly can further include a tear strap stitched to the skin and integrated with the skin. The composite shear strap can cover the tear strap, wherein the first shear strap flange and the second shear strap flange are stitched to the tear strap and integrated with the tear strap. With this arrangement, the stitched tear strap can help prevent crack propagation within the skin. For example, the tear strap can prevent a crack from propagating from a first side of the composite shear strap to a second side of the composite shear strap.

[0029] Various other features and variations of the described system and corresponding methods are described below with reference to the accompanying drawings.

[0030] Now referring Figure 1 , Figure 1 FIG. shows an aircraft wing 100 according to one example. As Figure 1 shown, the aircraft wing 100 includes a rear spar 102, a front spar 104, a lower skin 106, an upper skin 108, a plurality of spars 110, and a plurality of ribs 112. The rear spar 102, the front spar 104, the lower skin 106, the upper skin 108, the plurality of spars 110, and the plurality of ribs 112 can be made of the same or different composite materials. A composite material is two or more constituent materials having different physical or chemical properties. The composite material can be a non-crimp fabric composite material. The composite material can include, for example, a graphite composite material or a carbon fiber composite material.

[0031] Consistent with the above discussion, each of the plurality of ribs 112 can be connected to the lower skin 106 and the upper skin 108 using a shear strap. Figure 2 FIG. shows a partial view of an assembly 200 for connecting a rib of an aircraft wing to a skin 202 of the aircraft wing. The assembly 200 can be used, for example, to Figure 1 connect one of the plurality of ribs 112 to the lower skin 106 or the upper skin 108. As Figure 2 shown, the assembly 200 includes a discontinuous base charge 204, a composite shear strap 206, a spar base charge 208, and a spar 210.

[0032] The discontinuous base charge 204 can help counteract the resilience force generated by the shear strap flange to maintain a smooth and fluffy surface (skin 202). As Figure 2As shown, the discontinuous base charge 204 includes a first section 212 and a second section 214 separated by a spar base charge 208. With this arrangement, the spar base charge 208 can be in direct contact with the skin 202, eliminating any rocking along the length of the spar base charge 208, thereby increasing the compression capacity of the spar 210. When the skin 202 is the upper skin, increasing the compression capacity of the spar 210 can be beneficial because the upper skin can be subjected to significant compressive loads during flight.

[0033] The composite shear strap 206 includes a shear strap web 216, a first shear strap flange 218 extending from a first side of the shear strap web 216, a second shear strap flange 220 extending from a second side of the shear strap web 216, and a first shear strap fin 222 extending from an end of the first side of the shear strap web 216. The first shear strap flange 218 and the second shear strap flange 220 can be stitched along the length of the composite shear strap 206 to the discontinuous base charge 204 and be integral with the discontinuous base charge 204, thereby allowing the composite shear strap 206 to be co-cured with the discontinuous base charge 204 and the skin 102.

[0034] The shear strap web 216 includes a plurality of shear strap web layers 224 and includes a through-thickness stitch 226 disposed along the length of the shear strap web 216. The through-thickness stitch 226 can hold the plurality of shear strap web layers 224 together, which can strengthen the shear strap web 216 and help prevent each of the plurality of shear strap web layers 224 from separating from each other.

[0035] The spar 210 includes a spar web 228, a first spar flange 230 extending from a first side of the spar web 228, and a second spar flange 232 extending from a second side of the spar web 228. The first spar flange 230 and the second spar flange 232 can be stitched along the length of the spar 210 to the spar base charge 208 and the skin 202 and be integral with the spar base charge 208 and the skin 202.

[0036] The spar web 228 includes a plurality of spar web layers 234 and includes a through-thickness stitch 236 disposed along the length of the spar web 228. The through-thickness stitch 236 can hold the plurality of spar web layers 234 together, which can strengthen the spar web 228 and help prevent each of the plurality of spar web layers 234 from separating from each other. On a compression-dominated skin panel, this through-thickness stitch 236 contains any almost invisible impact damage that may not be detectable to grow under these compressive loads. This allows the spar 210 to work at a higher strain level than would otherwise be possible and thus saves weight.

[0037] In the assembled state, the longitudinal axis A1 of the composite shear strap 206 can be inclined with respect to the longitudinal axis A2 of the spar 210. For example, the longitudinal axis A1 can be substantially perpendicular to the longitudinal axis A2 (e.g., the angle between the longitudinal axis A1 and the longitudinal axis A2 can be an angle between 80° and 100°). In other examples, the angle between the longitudinal axis A1 and the longitudinal axis A2 can be larger or smaller, such as between 60° and 120°. Additionally, in the assembled state, the first shear strap flange 218 can be stitched to the first spar flange 230. Similarly, the second shear strap flange 220 can be stitched to the first spar flange 230. Further, the first shear strap fin 222 and the second shear strap fin 238 extending from the second side of the shear strap web 216 can be stitched to the spar web 228 and be integral with the spar web 228. This increases the shear strap pull - away capacity and stabilizes the spar web 228. Stitching the composite shear strap 206 to the spar 210 can allow the composite shear strap 206 to be integral with the spar 210 during the co - curing process. Additionally, without the stitching in the first shear strap flange 218 and the second shear strap flange 220, the composite shear strap 206 may not be able to react against the in - plane forces generated by the pressure loads in the wing at the inter - ply resin interface.

[0038] Although not shown in Figure 2 the composite shear strap 206 can also include a third shear strap fin extending from the first side of the shear strap web 216 and a fourth shear strap fin extending from the second side of the shear strap web 216, where the third shear strap fin and the fourth shear strap fin are stitched to the spar web of another spar and are integral with the spar web of the other spar (also not shown).

[0039] Additionally, Figure 2 a composite shear strap 206 is depicted where the first shear strap flange 218 and the second shear strap flange 220 have a length longer than the width of the first spar flange 230 such that portions of the first shear strap flange 218 and the second shear strap flange 220 directly abut the first section 212. However, in other examples, the lengths of the first shear strap flange 218 and the second shear strap flange 220 can be shorter. For example, the lengths of the first shear strap flange 218 and the second shear strap flange 220 can be approximately equal to the width of the first spar flange 230 such that portions of the first shear strap flange 218 and the second shear strap flange 220 do not extend beyond the width of the first spar flange 230.

[0040] As described above, one or more components of the assembly 200 can be made integral during a co-curing process. For example, during the co-curing process, the discontinuous base charge 204, the spar base charge 208, the skin 202, the first shear strap flange 218, and the first spar flange 230 can all be stitched together and then co-cured. Co-curing a first component to a second component can include stitching or otherwise adhering the first component to the second component, placing the two components in an oven, and curing the first and second components together in the oven.

[0041] Figure 3 A partial view of another assembly 300 for attaching a rib of an aircraft wing to a skin 302 of the aircraft wing is shown according to one example. The assembly 300 can be used, for example, to attach Figure 1 one of a plurality of ribs 112 to the lower skin 106 or the upper skin 108. As Figure 3 shown, similar to Figure 2 the assembly 200, the assembly 300 includes a composite shear strap 306, a spar base charge 308, and a spar 310. However, the assembly 300 differs from Figure 2 the assembly 200 in that the assembly 300 includes a continuous tear strip 304, while the assembly 200 includes a discontinuous base charge 204.

[0042] The continuous tear strip 304 can include a composite material strip located adjacent to the skin 302. The continuous tear strip 304 can extend continuously along the chord of the skin 302, such as between a front spar and a rear spar. With this arrangement, the spar base charge 308 may rock on the continuous tear strip 304. This can be more easily achieved when the composite shear strap 306, the spar base charge 308, and the spar 310 are co-cured together. Additionally, this arrangement can improve the ability of the skin 302 to withstand large cutouts in the skin 302 under high tension loads. Overlapping the tear strip under both the shear strap and the spar forms a grid of smaller compartments that can prevent cracking in the skin 302. With the shear strap, spar, shear strap tear strip, spar base charge, and skin in place, these reinforcement members can all be stitched together. This can facilitate increasing the percentage of zero-degree layers in the skin, thereby reducing weight. Improving the ability of the skin 302 to withstand cracking can be beneficial when the skin 302 is a lower skin, as the lower skin can experience significant tension loads during flight.

[0043] In addition, Figure 3Depicts a composite shear strap 306, where the first shear strap flange 318 and the second shear strap flange 320 have a length longer than the width of the first stringer flange 330, such that portions of the first shear strap flange 318 and the second shear strap flange 318 directly abut the continuous tear strip 304. However, in other examples, the lengths of the first shear strap flange 318 and the second shear strap flange 320 may be shorter. For example, the lengths of the first shear strap flange 318 and the second shear strap flange 320 may be approximately equal to the width of the first stringer flange 330, such that portions of the first shear strap flange 318 and the second shear strap flange 320 do not extend beyond the width of the first stringer flange 330.

[0044] Figure 4 Shows two different shear strap flap configurations according to an example. More specifically, Figure 4 Depicts a first shear strap flap configuration 400 and a second shear strap flap configuration 402.

[0045] Among other things, the first shear strap flap configuration 400 further includes a composite shear strap 404 and a stringer 406. For example, the composite shear strap 404 may represent Figure 3 the composite shear strap 306, and the stringer 406 may represent Figure 3 the stringer 310. As Figure 4 shown, the first shear strap flange 408 of the composite shear strap 404 is stitched to the first stringer flange 410 of the stringer 406. Additionally, the first shear strap flap 412 may be stitched to the stringer web 414 of the stringer 406. The first shear strap flap 412 and the first shear strap flange 408 are connected together by a butt joint.

[0046] Among other things, the second shear strap flap configuration 402 further includes a composite shear strap 416 and a stringer 418. The composite shear strap 416 may represent Figure 3 the composite shear strap 306, and the stringer 418 may represent Figure 3 the stringer 310. As Figure 4As shown, the first shear strap flange 420 of the composite shear strap 416 is stitched to the first spar flange 422 of the spar 418. Additionally, the first shear strap fin 424 may be stitched to the spar web 426 of the spar 418. The first shear strap flange 420 includes a plurality of shear strap flange layers 428 that are intertwined with a plurality of shear strap fin layers 430 of the first shear strap fin 424. Due to this overlapping butt joint between the first shear strap flange 420 and the first shear strap fin 424, the force required to pull the composite shear strap 416 away from the spar 418 can be greater than the force required to pull the composite shear strap 404 away from the spar 406. Thus, it may be advantageous to use the second shear strap fin configuration 402 in regions of the aircraft wing that are subject to high pull-off loads (such as the mid-wing), and to use the first shear strap fin configuration 400 in regions of the aircraft wing that are subject to lower pull-off loads.

[0047] Figure 5 A stitching technique according to one example is shown. As Figure 5 shown, the spar 502 may be stitched to the skin 504 of the aircraft wing. For example, during a spar stitching operation, the skin 504, the spar base stock 506, and the first spar flange 508 of the spar 502 may be stitched together using spar stitching 510. The spar stitching 510 may be provided along the entire length of the first spar flange 508 or along a portion of the first spar flange 508. The spar stitching 510 may capture the skin 504, the spar base stock 506, and the first spar flange 508.

[0048] As Figure 5 further shown, the composite shear strap 512 may be stitched to the skin 504, the tear strap 514, and the spar 502. For example, during a shear strap stitching operation, the first shear strap flange 516, the skin 504, the tear strap 514, and the first spar flange 508 may be stitched together using shear strap stitching 518. The shear strap stitching 518 may be provided along the entire length of the first shear strap flange 516 or along a portion of the first shear strap flange 516. The shear strap stitching 518 may capture the skin 504, the tear strap 514, and the first shear strap flange 516. Additionally, at the intersection of the spar 502 and the composite shear strap 512, the shear strap stitching 518 may capture the skin 504, the tear strap 514, the spar base stock 506, the first spar flange 508, and the first shear strap flange 516.

[0049] Figure 6 A partial view of another assembly 600 for connecting a rib of an aircraft wing to the skin 602 of the aircraft wing is shown. The assembly 600 may be used, for example, to Figure 1 connect one of a plurality of ribs 112 to the lower skin 106 or the upper skin 108. As Figure 6 shown, similar to Figure 2Component 200, component 600 includes a discontinuous base charge 604, a composite shear strap 606, a spar base charge 608 and a spar 610. In addition, the composite shear strap 606 includes a shear strap web 616, a first shear strap flange 618 extending from a first side of the shear strap web 616, and a second shear strap flange 620 extending from a second side of the shear strap web 616. Additionally, the spar 610 includes a first spar flange 630.

[0050] However, the composite shear strap 606 differs from Figure 2 the composite shear strap 206 in two aspects. First, the composite shear strap 206 includes a first shear strap fin 222 and a second shear strap fin 238, while the composite shear strap 606 does not include any shear strap fins. Second, the first shear strap flange 218 and the second shear strap flange 220 are arranged to be stitched to the first spar flange 230 and the first section 212 and are integral with the first spar flange 230 and the first section 212, while the first shear strap flange 618 and the second shear strap flange 620 are arranged to be stitched to the first section 612 of the discontinuous base charge 604, but not stitched to the first spar flange 630 of the spar 610.

[0051] Figure 7 A cross-sectional view of component 600 is shown. As Figure 6 shown, ribs 700 may be fastened to the composite shear strap 606. The composite shear strap 606 is positioned between the spar 610 and the second spar 710, but the composite shear strap 606 does not contact any spar flanges of the spar 610 or the second spar 710. Figure 7

[0052] Figure 8 A partial view of another component 800 for connecting ribs of an aircraft wing to the skin 802 of the aircraft wing according to an example is shown. Component 800 may be used, for example, to Figure 1 connect one of a plurality of ribs 112 to the lower skin 106 or the upper skin 108. As Figure 8 shown, similar to Figure 3 component 300, component 800 includes a continuous tear strip 804, a composite shear strap 806, a spar base charge 808 and a spar 810. In addition, the composite shear strap 806 includes a shear strap web 816, a first shear strap flange 818 extending from a first side of the shear strap web 816, and a second shear strap flange 820 extending from a second side of the shear strap web 816. Additionally, the spar 810 includes a first spar flange 630.

[0053] Figure 3 However, the composite shear strap 806 differs from Figure 3The composite shear strap 306. First, the composite shear strap 306 includes a first shear strap fin 322 and a second shear strap fin 238, while the composite shear strap 806 does not include any shear strap fins. Second, the first shear strap flange 318 and the second shear strap flange 320 are arranged to be stitched to the first spar flange 330 and the continuous tear strip 304 and integrated with the first spar flange 330 and the continuous tear strip 304, while the first shear strap flange 818 and the second shear strap flange 820 are arranged to be stitched to the continuous tear strip 804 but not stitched to the first spar flange 830 of the spar 810.

[0054] Figure 9 Suturing techniques are also shown. As Figure 9 shown, the composite shear strap 902 can be stitched to the skin 904 using a rounded corner suture 906 that encapsulates a rounded corner region 908 formed at the joint between the shear strap web 910, the first shear strap flange 912, and the second shear strap flange 914. The rounded corner suture 906 can prevent any rounded corner delamination from spreading into the shear strap web 910, the first shear strap flange 912, and the second shear strap flange 914.

[0055] As Figure 9 further shown, the composite shear strap 902 can be stitched to the skin 904 using a flange suture 916 provided along the length of the first shear strap flange 912. The flange suture 916 includes a flange inner suture 918, which can prevent damage growth in the first shear strap flange 912 and cause the first shear strap flange 912 to separate from the skin 904. The flange suture 916 also includes a flange edge suture 920. The first shear strap flange 912 includes an inclined outer edge 922 that is inclined in a first direction, and the flange edge suture 920 is inclined in the first direction. The flange edge suture 920 can help prevent damage occurring in another area of the skin 904 from weakening the connection between the composite shear strap 902 and the skin 904.

[0056] Figure 9 The suturing technique also provides support adjacent to the shear strap radius, thereby increasing the structural capacity. However, when manufacturing separate composite ribs with internal flanges that are bolted to the skin using vertical connections, the bolts should be placed further away from the shear strap radius, thereby increasing the stress on the shear strap radius and reducing the structural capacity. The internal flanges can cause the weight of such composite ribs to be excessive. Therefore, for example, Figure 9 the suturing technique helps with a composite assembly that is competitive in weight.

[0057] Figure 10 Two different flange edge configurations according to an example are shown. More specifically,

[0058] Figure 10Shows a first flange edge configuration 1000 and a second flange edge configuration 1002, which can be used for the shear band flange of a composite shear band or the stringer flange of a stringer.

[0059] As Figure 10 shown, the first flange edge configuration 1000 may include a first flange 1004 having an overlapping edge 1006 that covers the edge of the layer below the uppermost layer of the first flange 1004. For example, the first flange 1004 may be a stringer flange, and the overlapping edge 1006 may cover the ends of one or more stringer flange layers and the ends of one or more stringer base charge layers. Alternatively, the first flange 1004 may be a shear band flange, and the overlapping edge 1006 may cover the ends of one or more shear band flange layers and the ends of one or more tear strip layers.

[0060] As Figure 10 further shown, the second flange edge configuration 1002 includes a second flange 1008. However, unlike the first flange 1004, the second flange 1008 does not include an overlapping edge 1006. Instead, the second flange 1008 may be formed by a net molding process, where the ends of one or more layers of the second flange 1008 are covered with resin. The second flange edge configuration 1002 may be easier to manufacture than the first flange edge configuration. Therefore, it may be beneficial to apply the first flange edge configuration 1000 rather than the second flange edge configuration 1002 in areas of high electromagnetic threat level in an aircraft wing.

[0061] Figure 11 Shows a flowchart of a method 1100 according to an example. Figure 11 The method 1100 shown presents an embodiment of a method that may be performed, for example, to assemble any aircraft wing described herein, such as Figure 1 the aircraft wing 100. The method 1100 may be performed by one or more operators and / or one or more robotic devices.

[0062] The method 1100 may include one or more operations, functions, or actions shown in one or more of blocks 1102 - 1108. Although these blocks are shown in a sequential order, these blocks may also be performed in parallel and / or in an order different from the order described herein. Moreover, the various blocks may be combined into fewer blocks, divided into additional blocks, and / or removed based on the desired implementation.

[0063] Initially, at block 1102, method 1100 includes integrating the spar base charge with the skin of an aircraft wing during a co-curing process. The skin can be the upper skin or the lower skin of the aircraft wing. At block 1104, method 1100 includes integrating the spar with the spar base charge during the co-curing process. The spar includes a spar web, a first spar flange extending from a first side of the spar web, and a second spar flange extending from a second side of the spar web. At block 1106, method 1100 includes integrating a first shear strap flange of a composite shear strap with the first spar flange during the co-curing process. Consistent with the above discussion, the co-curing process can include stitching or otherwise bonding the first shear strap, the spar, and the spar base charge to the skin; placing the skin, the spar base charge, the spar, and the shear strap in an oven in their assembled state; and then curing the skin, the spar base charge, the spar, and the composite shear strap together in the oven.

[0064] At block 1108, method 1100 includes, after the co-curing process, fastening ribs to the shear strap web of the composite shear strap. The fastening at block 1108 can include inserting fasteners through holes in the shear strap web and holes in the ribs. The fastening at block 1108 can be performed by a robotic device having a movable base and a robotic arm.

[0065] Figure 12 Additional operations are shown that can be performed in conjunction with Figure 11 method 1100. Blocks 1110 and 1112 can be performed Figure 11 before block 1108 of Figure 12 .

[0066] At block 1110, Figure 12 includes integrating a continuous tear strip or a discontinuous base charge with the skin during the co-curing process. If the continuous tear strip is integrated with the skin, the spar base charge can cover the continuous tear strip. Alternatively, if the discontinuous base charge is integrated with the skin, the discontinuous base charge can include a first section and a second section separated by the spar base charge.

[0067] At block 1112, Figure 12 includes integrating a first shear strap flange of the composite shear strap and a second shear strap flange of the composite shear strap with the tear strip during the co-curing process.

[0068] As referenced in Figure 11 and Figure 12As described, method 1100 may include stitching together layers of the spar web. Additionally, method 1100 may include stitching together layers of the shear strap web. Additionally, method 1100 may include positioning the skin, the spar with spar base stock, the composite shear strap, the continuous tear strip, or the discontinuous base stock in an assembly tool. The assembly tool may hold the components in position relative to each other to facilitate stitching the components together.

[0069] Additionally, method 1100 may include stitching together the first spar flange, the spar base stock, and the skin, and stitching together the first shear strap flange, the continuous tear strip, or the discontinuous base stock, and the skin. At the intersection of the spar and the composite shear strap, the first shear strap flange, the first spar flange, the spar base stock, the continuous tear strip, or the discontinuous base stock, and the skin may be stitched together. The spar may be stitched to the spar base stock before positioning the spar and the spar base stock within the assembly tool.

[0070] Additionally, method 1100 may include co-curing the skin, the spar, the spar base stock, the composite shear strap, and the continuous tear strip or the discontinuous base stock in an oven. The front spar and the rear spar may also be co-cured with the components.

[0071] Additionally, the present disclosure includes embodiments according to the following clauses:

[0072] Clause 1. An assembly (200, 300, 600, 800) for attaching a rib of an aircraft wing to a skin of the aircraft wing, the assembly comprising:

[0073] A composite shear strap (206, 306, 404, 416, 512, 606, 806, 902) having a shear strap web (216, 616, 816, 910), a first shear strap flange (218, 318, 408, 420, 516, 618, 818, 912) extending from a first side of the shear strap web, a second shear strap flange (220, 320, 620, 820, 914) extending from a second side of the shear strap web, and a first shear strap tab (222, 322, 412, 424) extending from an end of the first side of the shear strap web;

[0074] A spar base stock (308, 506, 608, 808) stitched to the skin (106, 108, 202, 302, 504, 602, 802, 904) and integral with the skin (106, 108, 202, 302, 504, 602, 802, 904); and

[0075] Stringers (110, 210, 310, 406, 418, 502, 610, 810) that cover stringer base stock, the stringers including stringer webs (228, 414, 426), a first stringer flange (230, 330, 410, 422, 508, 620, 830) extending from a first side of the stringer web, and a second stringer flange (232) extending from a second side of the stringer web,

[0076] wherein, a first shear strap flange is stitched to and integral with the first stringer flange.

[0077] Clause 2. The assembly according to Clause 1, wherein a first shear strap tab is stitched to and integral with the first side of the stringer web.

[0078] Clause 3. The assembly according to Clause 1 or 2, wherein the first shear strap tab is stitched to and integral with the first stringer flange.

[0079] Clause 4. The assembly according to any one of Clauses 1-3, wherein the first shear strap tab includes a plurality of shear strap tab layers (430), wherein the first shear strap flange includes a plurality of shear strap flange layers (428) stitched to and integral with the first stringer flange, and wherein the plurality of shear strap tab layers are interwoven with the plurality of shear strap flange layers of the first shear strap flange.

[0080] Clause 5. The assembly according to any one of Clauses 1-4, further comprising tear straps (304, 514, 804) stitched to and integral with the skin, wherein the first shear strap flange and the second shear strap flange are stitched to and integral with the tear straps.

[0081] Clause 6. The assembly according to Clause 5, wherein the tear straps are continuous tear straps (304, 804), and wherein the stringer base stock covers the continuous tear straps.

[0082] Clause 7. The assembly according to any one of Clauses 1-6, wherein the skin is a lower skin (106) that is in tension during level flight.

[0083] Clause 8. The assembly according to any one of Clauses 5-7, wherein during the co-curing process: the tear straps and the stringer base stock are integral with the skin, and the first shear strap flange is integral with the first stringer flange.

[0084] Clause 9. The assembly according to any one of Clauses 1-8, further comprising discontinuous base stock (204, 604) stitched to and integral with the skin, the discontinuous base stock having a first section and a second section separated by the stringer base stock.

[0085] Clause 10. The component according to any one of Clauses 1-9, wherein the skin is an upper skin (108) that is in compression during level flight.

[0086] Clause 11. The component according to any one of Clauses 1-10, wherein the shear strap web includes a plurality of shear strap web layers (224), and wherein the shear strap web includes a through-thickness stitch (226) that holds the plurality of shear strap web layers together, the through-thickness stitch being provided along the length of the shear strap web.

[0087] Clause 12. The component according to any one of Clauses 1-11, wherein the longitudinal axis (A1) of the composite shear strap is inclined with respect to the longitudinal axis (A2) of the spar.

[0088] Clause 13. The component according to Clause 13, wherein the composite shear strap is stitched to the skin using a rounded corner stitch (906), wherein the rounded corner stitch encapsulates a rounded corner region (908) at the joint formed between the shear strap web, the first shear strap flange, and the second shear strap flange.

[0089] Clause 14. The component according to Clause 13, wherein the composite shear strap is stitched to the skin using a flange stitch (916), wherein the flange stitch includes at least one flange stitch (918, 920) provided along the length of the first shear strap flange.

[0090] Clause 15. The component according to Clause 14, wherein the at least one flange stitch includes a flange inner stitch (918) and a flange edge stitch (920), wherein the first shear strap flange includes an inclined outer edge (922) that is inclined in a first direction, and wherein the flange edge stitch is inclined in the first direction.

[0091] Clause 16. An aircraft wing (100) comprising:

[0092] Skin (106, 108, 202, 302, 504, 602, 802, 904);

[0093] A composite shear strap (206, 306, 404, 416, 512, 606, 806, 902) having a shear strap web (216, 616, 816, 910), a first shear strap flange (218, 318, 408, 420, 516, 618, 818, 912) extending from a first side of the shear strap web, a second shear strap flange (220, 320, 620, 820, 914) extending from a second side of the shear strap web, and a first shear strap tab (222, 322, 412, 424) extending from an end of the first side of the shear strap web;

[0094] Stringer bases (308, 506, 608, 808) stitched to and integral with the skin; and

[0095] Stringers (110, 210, 310, 406, 418, 502, 610, 810) covering the stringer bases, the stringers including stringer webs (228, 414, 426), a first stringer flange (230, 330, 410, 422, 508, 620, 830) extending from a first side of the stringer web, and a second stringer flange (232) extending from a second side of the stringer web,

[0096] wherein a first shear strap flange is stitched to and integral with the first stringer flange.

[0097] Clause 17. The aircraft wing according to clause 16, wherein a first shear strap tab is stitched to and integral with the first side of the stringer web.

[0098] Clause 18. The aircraft wing according to clause 16 or 17, wherein a first shear strap tab is stitched to and integral with the first stringer flange.

[0099] Clause 19. A method (1100) of manufacturing and assembling an aircraft wing, the method comprising:

[0100] Step (1102) of integrating a stringer base with the skin of the aircraft wing during a co-curing process;

[0101] Step (1104) of integrating a stringer with the stringer base during a co-curing process, the stringer including a stringer web, a first stringer flange extending from a first side of the stringer web, and a second stringer flange extending from a second side of the stringer web;

[0102] Step (1106) of integrating a first shear strap flange of a composite shear strap with the first stringer flange during a co-curing process; and

[0103] Step (1108) of fastening a composite rib to a shear strap web of the composite shear strap after the co-curing process.

[0104] Clause 20. The method according to clause 19, further comprising:

[0105] Step (1110) of integrating a continuous tear strip or a discontinuous base with the skin during a co-curing process; and

[0106] Step (1112) of integrating a first shear strap flange and a second shear strap flange of the composite shear strap with the continuous tear strip or the discontinuous base during a co-curing process.

[0107] Descriptions of different advantageous arrangements have been given for purposes of illustration and description, and are not intended to be exhaustive or limited to the examples of the disclosed forms. After reviewing and understanding the foregoing disclosure, many modifications and variations will be obvious to those of ordinary skill in the art. In addition, different examples may provide different advantages compared to other examples. The one or more examples selected and described are chosen to best explain the principles, practical applications, and to enable others of ordinary skill in the art to understand the disclosure of the various examples with various modifications suitable for the particular purposes contemplated.

Claims

1. An assembly (200, 300, 600, 800) for attaching a rib of an aircraft wing to the skin of the aircraft wing, the assembly comprising: Composite shear straps (206, 306, 404, 416, 512, 606, 806, 902) having a shear strap web (216, 616, 816, 910), a first shear strap flange (218, 318, 408, 420, 516, 618, 818, 912) extending from a first side of the shear strap web, a second shear strap flange (220, 320, 620, 820, 914) extending from a second side of the shear strap web, and a first shear strap tab (222, 322, 412, 424) extending from an end of the first side of the shear strap web; Stringer base stock (308, 506, 608, 808) stitched to the skin (106, 108, 202, 302, 504, 602, 802, 904) and integral with the skin (106, 108, 202, 302, 504, 602, 802, 904); and Stringers (110, 210, 310, 406, 418, 502, 610, 810) covering the stringer base stock, the stringers including a stringer web (228, 414, 426), a first stringer flange (230, 330, 410, 422, 508, 630, 830) extending from a first side of the stringer web, and a second stringer flange (232) extending from a second side of the stringer web, wherein the first shear strap flange is stitched to and integral with the first stringer flange, wherein the assembly includes discontinuous base stock (204, 604) stitched to and integral with the skin, the discontinuous base stock having a first section and a second section separated by the stringer base stock such that the stringer base stock is in direct contact with the skin.

2. The assembly according to claim 1, wherein, the first shear strap tab is stitched to and integral with the first side of the stringer web.

3. The assembly according to claim 2, wherein, the first shear strap tab is stitched to and integral with the first stringer flange.

4. The assembly according to claim 3, wherein, the first shear strap tab includes a plurality of shear strap tab layers (430), wherein the first shear strap flange includes a plurality of shear strap flange layers (428) stitched to and integral with the first stringer flange, and wherein the plurality of shear strap tab layers are interwoven with the plurality of shear strap flange layers of the first shear strap flange.

5. The assembly according to any one of claims 1 to 4, further comprising tear straps (304, 514, 804) stitched to and integral with the skin, wherein, the first shear strap flange and the second shear strap flange are stitched to and integral with the tear straps.

6. The component according to claim 5, wherein, the tear strip is a continuous tear strip (304, 804), and wherein the stringer base stock covers the continuous tear strip.

7. The component according to any one of claims 1 to 4, wherein, the shear strap web includes a plurality of shear strap web layers (224), and wherein the shear strap web includes a through-thickness stitch (226) that holds the plurality of shear strap web layers together, the through-thickness stitch being provided along the length of the shear strap web.

8. The component according to any one of claims 1 to 4, wherein, the longitudinal axis (A1) of the composite shear strap is inclined with respect to the longitudinal axis (A2) of the stringer.

9. The component according to any one of claims 1 to 4, wherein, the composite shear strap is stitched to the skin using a rounded corner stitch (906), wherein the rounded corner stitch encapsulates a rounded corner region (908) at the joint formed between the shear strap web, the first shear strap flange, and the second shear strap flange.

10. The component according to claim 9, wherein, the composite shear strap is stitched to the skin using a flange stitch (916), wherein the flange stitch includes at least one flange stitch (918, 920) provided along the length of the first shear strap flange.

11. The component according to claim 10, wherein, the at least one flange stitch includes a flange inner stitch (918) and a flange edge stitch (920), wherein the first shear strap flange includes an inclined outer edge (922) that is inclined in a first direction, and wherein the flange edge stitch is inclined in the first direction.

12. An aircraft wing (100), comprising: skin (106, 108, 202, 302, 504, 602, 802, 904); and the component according to any one of claims 1 to 11.

13. A method (1100) of manufacturing and assembling an aircraft wing, the method comprising: step (1102) of integrating the stringer base stock with the skin of the aircraft wing during a co-curing process; step (1104) of integrating the stringer with the stringer base stock during the co-curing process, the stringer including a stringer web, a first stringer flange extending from a first side of the stringer web, and a second stringer flange extending from a second side of the stringer web; step (1106) of integrating the first shear strap flange of the composite shear strap with the first stringer flange during the co-curing process; and step (1108) of fastening a composite rib to the shear strap web of the composite shear strap after the co-curing process, wherein the method further includes stitching and integrating a discontinuous base stock to the skin during the co-curing process, the discontinuous base stock having a first section and a second section separated by the stringer base stock such that the stringer base stock is in direct contact with the skin.

14. The method according to claim 13, further comprising: Step (1110), integrating a continuous tear strip with the skin during the co-curing process; and Step (1112), integrating the first shear strap flange of the composite shear strap and the second shear strap flange of the composite shear strap with the continuous tear strip or the discontinuous base charge during the co-curing process.

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