Patent Application
20210016524
This application relates to composite structures and, more particularly, to methods for manufacturing composite structures, such as stringers, that include a bevel along an edge thereof.
Composite structures having bevels often find utility in a variety of applications, including in the aerospace industry. Stringers used to reinforce aircraft skin panels are an example of such a composite structure, as they include bevels formed laterally along the length of the stringer.
One current method for manufacturing composite structure with bevels generally entails forming the composite structure and then trimming away excess material to produce the bevel. However, this method is inefficient due to the wasted cost of the excess material and the time required to trim it off.
Another current method for manufacturing composite structure with bevels generally entails arranging plies of composite material in a stepwise (e.g., “pyramid”) arrangement. However, this method results in a bevel defined by exposed ply edges, which presents a vulnerability in the composite structure as the exposed edges are more susceptible to environmental damage as well as damage through use. Furthermore, small bevel angles are difficult achieve with this method.
Accordingly, those skilled in the art continue with research and development efforts in the field of manufacturing composite structures with bevels.
Disclosed are composite structures and methods for manufacturing composite structures.
In one example, the disclosed method for manufacturing a composite structure includes trimming plies of composite material to a near net-shape, thereby yielding a plurality of net-trimmed plies, wherein each net-trimmed ply of the plurality of net-trimmed plies comprises an edge. The disclosed method further includes assembling a layup that includes the plurality of net-trimmed plies, wherein the assembling of the layup includes staggering the edges of the plurality of net-trimmed plies such that the edges define a staggered edge structure. The disclosed method further includes pressing the layup to form the staggered edge structure into a bevel.
In another example, the disclosed method for manufacturing a composite structure includes cutting a bulk supply of composite material to yield a plurality of net-trimmed plies that include at least a first net-trimmed ply, a second net-trimmed ply and a third net-trimmed ply, each net-trimmed ply of the plurality of net-trimmed plies includes an edge, a length and a width, and wherein at least one of the length and the width is constant across each net-trimmed ply of the plurality of net-trimmed plies. The disclosed method further includes positioning each net-trimmed ply of the plurality of net-trimmed plies on a layup tool to yield a layup. The disclosed method further includes staggering the edges of the plurality of net-trimmed plies such that the edges define a staggered edge structure wherein the edge of the first net-trimmed ply and the edge of the third net-trimmed ply protrude outward beyond the edge of the second net-trimmed ply. The disclosed method further includes pressing the layup to form the staggered edge structure into a bevel.
In one example, the disclosed composite structure includes a plurality of net-trimmed plies, wherein each net-trimmed ply of the plurality of net-trimmed plies includes an edge. The disclosed composite structure further includes an edge portion that includes a bevel defined by at least one net-trimmed ply of the plurality of net-trimmed plies, the edge portion further includes the edges of the plurality of net-trimmed plies.
Other examples of the disclosed composite structures and methods will become apparent from the following detailed description, the accompanying drawings and the appended claims.
The following detailed description refers to the accompanying drawings, which illustrate specific examples described by the disclosure. Other examples having different structures and operations do not depart from the scope of the present disclosure. Like reference numerals may refer to the same feature, element, or component in the different drawings.
Illustrative, non-exhaustive examples, which may be, but are not necessarily, claimed, of the subject matter according the present disclosure are provided below. Reference herein to “example” means that one or more feature, structure, element, component, characteristic and/or operational step described in connection with the example is included in at least one embodiment and/or implementation of the subject matter according to the present disclosure. Thus, the phrase “an example” and similar language throughout the present disclosure may, but do not necessarily, refer to the same example. Further, the subject matter characterizing any one example may, but does not necessarily, include the subject matter characterizing any other example.
Referring to
As used herein, “net-trimmed,” “net-trimmed plies” and “near net-shape plies” refers to plies of composite material that have been cut such that once the plies are assembled into a layup and then formed into a final composite structure, the final composite structure will require minimal, if any, finishing. The layup assembled from net-trimmed plies may be referred to as being “near net-shape” due to the layup being very close to the desired (e.g., “net”) shape of the final composite structure. Those skilled in the art will appreciate that net-trimming plies and/or assembling near net-shape layups may be preferred in many applications because post-production finishing adds undesired time and cost to the manufacturing process.
The method 100 includes trimming plies of composite material to a near net-shape (block 120), thereby yielding a plurality of net-trimmed plies 30, wherein each net-trimmed ply 30 of said plurality of net-trimmed plies 30 includes an edge 32. Each net-trimmed ply 30 of the plurality of net-trimmed plies 30 may be trimmed into varying shapes and dimensions based on, among other things, the size and/or shape of the subsequent layup 20 to be assembled, as well as the finished composite structure 10. In one example, the method 100 may include trimming the plies of composite material 50 such that each net-trimmed ply 30 of the plurality of net-trimmed plies 30 includes a length L and a width W, and that at least one of the length L and the width W is constant across each net-trimmed ply 30 of the plurality of net-trimmed plies 30. In another example, the method 100 may include trimming the plies of composite material 50 such that both the length L and the width W is constant across each net-trimmed ply 30 of the net-trimmed plurality of plies 30. In yet another example, the method 100 may include trimming the plies of composite material 50 such that each net-trimmed ply 30 of the plurality of net-trimmed plies 30 is substantially rectangular. Those skilled in the art will appreciate that net-trimmed plies 30 may be trimmed into non-rectangular shapes, non-polygonal shapes, and even irregular shapes without departing from the scope of the present disclosure. Those skilled in the art will also appreciate, however, that rectangular net-trimmed plies having straight edges will typically be faster and cheaper to produce, due to the simplicity of the shape.
Referring to
Once a plurality of net-trimmed plies 30 has been obtained, the assembling of the layup (block 130) may further include placing each net-trimmed ply 30 of the plurality of net-trimmed plies 30 on a layup tool 52 (block 140). The layup tool 52 may include any structure with a suitable surface upon which a layup may be assembled, such as a die or a mold. Those skilled in the art will appreciate that the actual surface upon which the plurality of net-trimmed plies 30 is to be placed may vary in shape (e.g., planar or contoured) without departing from the scope of the present disclosure. This step (block 140) may be performed, for example, by stacking net-trimmed plies 30 on top of one another to yield the layup 20 shown in
Upon placement (block 140), the position of each net-trimmed ply 30 relative to other net-trimmed plies 30 of the plurality of net-trimmed 30 plies may vary. As shown in
Referring to
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The pressing of the layup (block 170) may be performed by any suitable means, such as by positioning the layup 20 between a first die 56 and a second die 58, and then approximating the first die 56 and the second die 58 to press the layup 20. Those skilled in the art will appreciate that other processing conditions related to the pressing, such as the degree of compressive force and/or the compression time, may vary without departing from the scope of the present disclosure.
Referring to
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Those skilled in the art will appreciate, however, that the staggered edge structure 22 in any given example may include multiple instances wherein a superjacent net-trimmed ply 30B and a subjacent net-trimmed ply 30I have edges 32B, 32I that protrude outward beyond the edge 32F of a net-trimmed ply 30F positioned between them, even if there are additional net-trimmed plies 30C-30E, 30G-30H positioned between the superjacent net-trimmed ply 30B and the subjacent net-trimmed ply 30I.
Still referring to
In another example, the assembling of the layup (block 130) may further include staggering the edge 32J of the second exterior net-trimmed ply 30J relative to every other edge 32A-32I of the plurality of net-trimmed pies 30 such that the edge 32J of the second exterior net-trimmed ply 30J protrudes outward beyond every other edge 32A-32I of the plurality of net-trimmed plies 30 except for the edge 32A of the first exterior net-trimmed ply 30A. At this point, those skilled in the art will appreciate that upon pressing the layup 20 in this example, at least one of the first exterior net-trimmed ply 30A and the second exterior net-trimmed ply 30J may fold over at least some, if not all, of the edges 32B-32I of the other net-trimmed plies 30B-301 of the plurality of net-trimmed plies 30. As shown in
The plurality of net-trimmed plies 30 may include net-trimmed plies 30 having various fiber orientations 36. For example, the plurality of net-trimmed plies 30 may include net-trimmed plies 30 having a first fiber orientation 36D, net-trimmed plies 30 having a second fiber orientation 36E, and net-trimmed plies 30 having a third fiber orientation 36F. As shown in
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Each net-trimmed ply 30 of the plurality of net-trimmed plies 30 of the composite structure 10 may vary in shape. In one example, each net-trimmed ply 30 of the plurality of net-trimmed plies 30 may include a length L and a width W, wherein at least one of the length L and the width W is constant across each net-trimmed ply 30 of the plurality of net-trimmed plies 30. In another example, both the length L and the width W may be constant across each net-trimmed ply 30 of the plurality of net-trimmed plies 30. In yet another example, each net-trimmed ply 30 of the plurality of net-trimmed plies 30 may be substantially rectangular.
Within the edge portion 14 of the composite structure 10, the position of any given edge 32 of the plurality of net-trimmed plies 30 relative to the other edges 32 may vary. In one or more examples, the edges 32 may be substantially parallel to one another. In other examples, the edges 32 may be rotationally offset either due to the way the net-trimmed plies 30 were placed or due to the shapes of the net-trimmed plies 30 to which the edges 32 belong. Further, the positions of any given edge 32 of the plurality of net-trimmed plies 30 may also vary in terms of the degree to which they protrude outward in a protruding direction 54. Where the edges 32 protrude outward to non-uniform extents, the edges 32 may be considered “staggered.”
In one example, the plurality of net-trimmed plies 30 may include a first net-trimmed ply 30B having a first edge 32B, a second net-trimmed ply 30E having a second edge 32E, and a third net-trimmed ply 30H having a third edge 32H. In this example, the first and third plies 30B, 30H may be positioned relative to the second ply 30E such that the first edge 32B and the third edge 32H may protrude outward beyond the second edge 32E.
In another example, the plurality of net-trimmed plies 30 may include a first exterior net-trimmed ply 30A and a second exterior net-trimmed ply 30J, and every other net-trimmed ply 30B-301 of the plurality of net-trimmed plies 30 may be positioned the first exterior net-trimmed ply 30A and the second exterior net-trimmed ply 30J. In this example, the edge 32A of the first exterior net-trimmed ply 30A may protrude outward beyond every other edge 32B-32J of the plurality of net-trimmed plies 30. Further, the first exterior net-trimmed ply 30A may be folded over at least some, if not all, of the edges 32B-32J of the other net-trimmed plies 30B-30J of the plurality of net-trimmed plies 30.
In yet another example, the plurality of net-trimmed plies 30 may include a first exterior net-trimmed ply 30A and a second exterior net-trimmed ply 30J, and every other net-trimmed ply 30B-301 of the plurality of net-trimmed plies 30 may be positioned the first exterior net-trimmed ply 30A and the second exterior net-trimmed ply 30J. In this example, the edge 32J of the second exterior net-trimmed ply 30J may protrude outward beyond every other edge 32A-32I of the plurality of net-trimmed plies 30 except for the edge 32A of the first exterior net-trimmed ply 30A. As such, at least one of the first exterior net-trimmed ply 30A and the second exterior net-trimmed ply 30J may be folded over at least some, if not all, of the edges 32B-32I of the other net-trimmed plies 30B-301 of the plurality of net-trimmed plies 30.
The plurality of net-trimmed plies 30 may also include net-trimmed plies 30 having various fiber orientations 36. These net-trimmed plies 30 may be positioned relative to one another such that their fiber orientations 36 are offset. In one example, the plurality of net-trimmed plies 30 includes a first net-trimmed ply 30C having a first fiber orientation 36C and a second net-trimmed ply 30F, 30G having a second fiber orientation 36F, 36G. In this example, the second fiber orientation 36G may be offset relative to the first fiber orientation 36C by about 45°. In another example, the second fiber orientation 36F may be offset relative to the first fiber orientation 36C by about 90°. Those skilled in the art will appreciate that other offset angles may be employed without departing from the scope of the present disclosure.
The bevel 12 formed in the edge portion 14 of the composite structure 10 may define a bevel angle θ. In one example, the bevel angle θ may be about 5°. In another example, the bevel angle θ may be about 10°. In yet another example, the bevel angle θ may be about 15°. Those skilled in the art will appreciate that the bevel 12 may define various other bevel angles θ without departing from the scope of the present disclosure.
Examples of the disclosure may be described in the context of an aircraft manufacturing and service method 400, as shown in
Each of the processes of method 400 may be performed or carried out by a system integrator, a third party, and/or an operator (e.g., a customer). For the purposes of this description, a system integrator may include without limitation any number of aircraft manufacturers and major-system subcontractors; a third party may include without limitation any number of venders, subcontractors, and suppliers; and an operator may be an airline, leasing company, military entity, service organization, and so on.
As shown in
The disclosed composite structure and method for manufacturing a composite structure may be employed during any one or more of the stages of the aircraft manufacturing and service method 400. As one example, the disclosed composite structure and method for manufacturing a composite structure may be employed during material procurement 406. As another example, components or subassemblies corresponding to component/subassembly manufacturing 408, system integration 410, and or maintenance and service 416 may be fabricated or manufactured using the disclosed composite structure and method for manufacturing a composite structure. As another example, the airframe 418 and the interior 422 may be constructed using the disclosed composite structure and method for manufacturing a composite structure. Also, one or more apparatus examples, method examples, or a combination thereof may be utilized during component/subassembly manufacturing 408 and/or system integration 410, for example, by substantially expediting assembly of or reducing the cost of an aircraft 402, such as the airframe 418 and/or the interior 422. Similarly, one or more of system examples, method examples, or a combination thereof may be utilized while the aircraft 402 is in service, for example and without limitation, to maintenance and service 416.
The disclosed composite structure and method for manufacturing a composite structure are described in the context of an aircraft; however, one of ordinary skill in the art will readily recognize that the disclosed composite structure and method for manufacturing a composite structure may be utilized for a variety of applications. For example, the disclosed composite structure and method for manufacturing a composite structure may be implemented in various types of vehicles including, e.g., helicopters, passenger ships, automobiles and the like.
Although various examples of the disclosed composite structure and method for manufacturing a composite structure have been shown and described, modifications may occur to those skilled in the art upon reading the specification. The present application includes such modifications and is limited only by the scope of the claims.
