Co-curable and co-cured UV / visible light-resistant peel ply application for composite material assemblies

Abstract

To provide a co-curable composite material assembly precursor and a method for producing the precursor.SOLUTION: Provided are co-curable and co-cured UV / visible light-resistant composite material assembly precursors used to produce composite material assemblies, including a compatible co-curable and co-cured peel ply protective layer, in which selected surface characteristics are imparted to the co-curable and co-cured composite material assembly precursors prior to peel ply removal and composite material precursor incorporation into a larger assembly.SELECTED DRAWING: None

Description

[Technical field]

[0001] Related Applications

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 468,070, filed May 22, 2023, the entire contents of which are incorporated herein by reference.

[0002]

[0002] The present disclosure relates generally to the field of composite materials, and to the field of composite materials used to manufacture large structural components and assemblies. In particular, the present disclosure relates to the field of co-curable and co-cured composite materials used in structural materials for large structural aircraft parts and assemblies. [Background technology]

[0003]

[0003] The use of composite materials in the manufacture of various structural component parts continues to grow. At least for strength to weight ratio, composite materials offer advantages as alternatives to denser materials such as metals and metal alloys. The overall weight of a completed structure (or the weight of a component part of a completed structure) is an important consideration in the selection of materials used in the manufacture of such a completed structure, or in the manufacture of a component of a completed structure.

[0004]

[0004] Coating layers that are typically applied to composite materials are not as durable or long-lived as the composite materials to which they are applied. Composite material assemblies may include other exterior or interior layers that may include, for example, protective coatings or other coating layers.

[0005]

[0005] Unless expressly stated otherwise, statements in this specification are not admitted to be prior art by virtue of being included merely in the technical field and / or background art. Summary of the Invention

[0006]

[0006] The disclosed apparatus, systems, and methods are directed to surface modification of a composite precursor that includes a co-curable and co-cured composite precursor that includes a UV / visible light resistant layer, using a removable co-curable and co-cured peel ply layer that is compatible with the UV / visible light resistant layer in the composite precursor to provide increased surface energy and improved secondary bonding at the composite precursor surface interface.

[0007]

[0007] Several present aspects are directed to a first co-curable composite assembly precursor. The first co-curable composite assembly precursor includes a co-curable composite stack, the co-curable composite stack including a co-curable composite substrate and a co-curable UV / visible light resistant layer. The first co-curable UV / visible light resistant layer is disposed adjacent to the co-curable composite substrate. The co-curable UV / visible light resistant layer includes a first co-curable UV / visible light resistant resin and further includes at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, quartz, and combinations thereof. The co-curable composite assembly precursor further includes a co-curable peel ply fiber and a resin-containing layer disposed adjacent to the UV / visible light resistant layer. The co-curable peel ply fiber and resin-containing layer comprises at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, and combinations thereof, and further comprises a second co-curable UV / visible light resistant resin that is compatible with the co-curable UV / visible light resistant layer.

[0008] In another aspect, the first co-curable UV / visible light resistant resin is the same as the second co-curable UV / visible light resistant resin.

[0009] In another aspect, the first co-curable UV / visible light resistant resin is not the same as the second co-curable UV / visible light resistant resin.

[0010] In another aspect, the first co-curable UV / visible light resistant resin is compatible with the second co-curable UV / visible light resistant resin.

[0011]

[0011] In another aspect, the co-curable composite substrate is co-curable with a co-curable UV / visible light resistant layer at temperatures in the range of about 250 degrees Fahrenheit to about 410 degrees Fahrenheit, and is further co-curable with a co-curable peel ply fiber and resin-containing layer.

[0012] In a further aspect, a co-curable composite substrate comprises a carbon fiber reinforced polymer.

[0013]

[0013] In another aspect, a co-curable composite substrate comprises an epoxy resin-based compound and further comprises at least one of carbon fibers, boron fibers, aramid fibers, fiberglass fibers, polyester fibers, and combinations thereof.

[0014]

[0014] In another aspect, a co-curable composite substrate includes a plurality of carbon fiber reinforced polymer prepregs.

[0015] In another embodiment, the co-curable composite substrate is in direct contact with the co-curable UV / visible light resistant layer.

[0016] In a further aspect, the co-curable UV / visible light resistant layer completely covers at least one side of the co-curable composite substrate.

[0017] Aspects of the present disclosure are further directed to a co-cured composite assembly precursor (a co-cured composite "stack" with a co-cured peel ply). The co-cured composite assembly precursor includes a co-cured composite substrate and a co-cured UV / visible light resistant layer. The co-curable UV / visible light resistant layer is disposed adjacent to the first composite substrate and includes a first co-curable UV / visible light resistant resin and further includes at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, quartz, and combinations thereof. The co-cured composite assembly precursor further includes a co-cured peel ply and a resin-containing layer disposed adjacent to the co-cured UV / visible light resistant layer. The co-cured peel ply and the resin-containing layer further includes a second co-cured UV / visible light resistant resin that is compatible with the co-curable UV / visible light resistant layer.

[0018] In another aspect, the peel ply and the resin-containing layer that are co-cured comprise at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, and combinations thereof.

[0019]

[0019] In another aspect, when the co-curable UV / visible light resistant layer has an average thickness in the range of about 2 mils to about 6 mils, for UV / visible light wavelengths in the range of about 180 nm to about 800 nm, the co-cured UV / visible light resistant layer has a light transmittance value in the range of about 0% to about 20% UV / visible light transmittance.

[0020]

[0020] In another aspect, a co-cured composite substrate is co-cured with a co-curable UV / visible light resistant layer at a temperature in the range of about 250°F to about 410°F and can be further co-cured with a co-curable peel ply fiber and resin-containing layer.

[0021]

[0021] In a further aspect, a co-cured composite substrate comprises an epoxy resin-based compound and further comprises at least one of carbon fibers, boron fibers, aramid fibers, fiberglass fibers, polyester fibers, and combinations thereof.

[0022]

[0022] In another aspect, a co-cured composite substrate is formed from a plurality of carbon fiber reinforced polymer prepregs.

[0023]

[0023] Further present aspects are directed to a co-curable composite assembly precursor (a co-curable "stringer / assembly precursor" with peel ply). The co-curable composite assembly precursor includes a co-curable composite substrate (stringer) and a co-curable peel ply fiber and resin-containing layer disposed adjacent to the co-curable composite substrate. The co-curable peel ply fiber and resin-containing layer further include a co-curable UV / visible light resistant resin.

[0024] In another aspect, the co-curable composite substrate comprises a carbon fiber reinforced polymer.

[0025]

[0025] In another aspect, a co-curable composite substrate comprises an epoxy resin-based compound and further comprises at least one of carbon fibers, boron fibers, aramid fibers, fiberglass fibers, polyester fibers, and combinations thereof.

[0026]

[0026] In another aspect, a co-curable composite substrate includes a plurality of carbon fiber reinforced polymer prepregs.

[0027]

[0027] Further present aspects are directed to a co-cured aircraft assembly precursor that includes a co-cured ("stringer / assembly precursor") composite substrate (stringer) and a co-cured peel ply fiber and resin-containing layer disposed adjacent to the co-curable composite substrate. The co-cured peel ply fiber and resin-containing layer further include a co-curable UV / visible light resistant resin.

[0028] In another aspect, the co-cured composite substrate comprises a carbon fiber reinforced polymer.

[0029]

[0029] In a further aspect, a co-cured composite substrate comprises an epoxy resin-based compound and further comprises at least one of carbon fibers, boron fibers, aramid fibers, fiberglass fibers, polyester fibers, and combinations thereof.

[0030] In a further aspect, a co-cured composite substrate includes a plurality of carbon fiber reinforced polymer prepregs.

[0031] Another present aspect is directed to a method (for making a "first" precursor of a co-cured composite assembly by adding a peel ply to a skin / stack). The method includes providing a first co-curable composite substrate and adding a co-curable UV / visible light resistant layer onto the first composite substrate. The co-curable UV / visible light resistant layer includes a first co-curable UV / visible light resistant resin and at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, quartz, and combinations thereof. The method further includes adding a co-curable peel ply fiber and resin-containing layer adjacent to the co-curable UV / visible light resistant layer to form a first precursor of a co-curable composite assembly. The co-curable peel ply fibers and resin-containing layer further include a second co-curable UV / visible light resistant resin that is compatible with the co-curable UV / visible light resistant layer and further include a peel ply backing layer covering the co-curable peel ply fibers and resin-containing layer. The method further includes co-curing the co-curable composite substrate with the co-curable UV / visible light resistant layer and the co-curable peel ply fibers and resin-containing layer to form a first precursor of a co-cured composite assembly.

[0032]

[0032] In a further aspect, when the co-curable UV / visible light resistant layers have an average thickness in the range of about 2 mils to about 6 mils, the co-cured UV / visible light resistant layers in the first precursor of the co-cured composite assembly have a UV / visible light transmittance value in the range of about 0% to about 20% UV / visible light transmittance for UV / visible light wavelengths in the range of about 180 nm to about 800 nm.

[0033] In another aspect, the co-curable UV / visible light resistant layer is applied to the co-curable composite substrate as a single ply.

[0034] In another aspect, the co-curable composite substrate comprises a carbon fiber reinforced polymer composite substrate.

[0035] In another aspect, a co-curable composite substrate includes a fiber reinforced epoxy resin matrix, the fiber reinforced epoxy resin matrix including at least one of carbon fiber, boron fiber, aramid fiber, fiberglass fiber, polyester fiber, and combinations thereof.

[0036] A further present aspect is directed to a first precursor of a co-cured composite assembly made according to the methods presented herein.

[0037]

[0037] In another present aspect, a method for making a second precursor of a co-cured composite assembly is provided. The second precursor of the co-cured composite assembly is configured to be bonded to the first precursor of the co-cured composite assembly. The method includes providing a co-curable second composite substrate and adding a co-curable peel ply fiber and a resin-containing layer adjacent to the co-curable second composite substrate to form a co-curable composite second precursor. The co-curable peel ply fiber and the resin-containing layer further include a co-curable UV / visible light resistant resin that is compatible with the co-curable UV / visible light resistant layer in a co-cured state, and further include a peel ply backing layer covering the co-curable peel ply fiber and the resin-containing layer. The method further includes co-curing the co-curable second composite substrate with the co-curable peel ply fiber and the resin-containing layer to form a co-cured composite second precursor.

[0038] Further aspects herein are directed to co-cured second composite assembly precursors made according to the methods presented herein.

[0039]

[0039] In another aspect, a method for making a co-cured composite assembly second precursor configured to be bonded to a co-cured composite assembly first precursor further includes removing a peel ply backing layer from the co-cured composite assembly first precursor to form an exposed surface of the UV / visible light resistant resin layer of the co-cured composite assembly first precursor, removing the peel ply backing layer from the co-cured composite assembly second precursor to form an exposed surface of the UV / visible light resistant resin layer of the co-cured composite assembly second precursor, applying an adhesive layer to at least one of the exposed surface of the UV / visible light resistant resin layer of the co-cured composite assembly first precursor and the exposed surface of the UV / visible light resistant resin layer of the co-cured composite assembly second precursor, and bonding the co-cured first composite assembly precursor to a co-cured second composite assembly precursor to form a composite assembly.

[0040] A further aspect is directed to a composite material assembly made according to the methods disclosed herein.

[0041] A further aspect is directed to a vehicle including a composite material assembly made according to the present method.

[0042] Another present aspect is directed to an aircraft including a composite assembly made according to the present method.

[0043]

[0043] The above-described features, functions, and advantages can be realized alone in various aspects or can be combined in further multiple aspects, details of which can be confirmed by referring to the following description and the attached drawings.

[0044]

[0044] Having described the present disclosure in general terms, reference is now made to the accompanying drawings, which are not necessarily drawn to scale. [Brief description of the drawings]

[0045] [Figure 1A]

[0045] FIG. 1 is a diagram of a vehicle taking the form of an aircraft according to several of the present aspects. [Figure 1B]

[0046] 1 is a cross-sectional view of an aircraft fuel tank within a wing of an aircraft according to several present aspects. [Figure 2A]

[0047] FIG. 2 is an enlarged cross-sectional representative side view of a UV / visible light resistant co-curable composite stack according to several present embodiments. [Figure 2B]

[0048] FIG. 2 is an enlarged cross-sectional representative side view of a UV / visible light resistant co-cured composite stack according to several present embodiments. [Figure 2C]

[0049] FIG. 2 is an enlarged cross-sectional representative side view of a UV / visible light resistant co-cured composite stack according to several present embodiments. [Diagram 3]

[0050] 1 is a cross-sectional representative side view of a co-curable composite stack progressing through a curing stage to form a co-cured composite stack according to several present embodiments. FIG. [Figure 4A]

[0051] 1 is a cross-sectional representative side view of a co-curable composite stack precursor and an aircraft structural precursor progressing through manufacturing stages to form an aircraft assembly, according to multiple present aspects. FIG. [Figure 4B]

[0052] 1 is a cross-sectional representative side view of a co-curable composite stack precursor and an aircraft structural precursor progressing through manufacturing stages to form an aircraft assembly, according to multiple present aspects. FIG. [Diagram 5]

[0053] 1 is a flow chart outlining a method according to several present aspects. [Figure 6]

[0054] 1 is a flow chart outlining a method according to several present aspects. [Figure 7]

[0055] 1 is a flow chart outlining a method according to several present aspects. [Figure 8]

[0056] 1 is a flow chart outlining a method according to several present aspects. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046]

[0057] Several present embodiments are directed to a surface treatment of co-curable and co-cured composite precursors (equivalently referred to herein as "composite assembly precursors") used in the manufacture of composite assemblies, which may be, for example, structural assemblies. The surface treatment can increase the surface energy of the exposed surface of the treated composite precursor and significantly improve secondary bonding of this exposed surface through the addition of a co-curable and co-cured peel ply layer that is compatible with the composite material including a UV / visible light resistant material. The peel ply itself includes a UV / visible light resistant material that is compatible and co-curable with the UV / visible light resistant material-containing composite material.

[0047]

[0058] During the manufacture of composite parts that may be used to manufacture larger structural assemblies (such as aircraft assemblies that are incorporated into an aircraft), the composite surfaces of the composite parts (which may include, for example, epoxy-based composites, carbon fiber reinforced polymer materials, etc.) may begin to degrade due to exposure to ambient ultraviolet / visible (UV / vis) radiation. To avoid changes to the surface or other properties of the composite material (including, for example, discoloration, etc.) that may be at least partially caused by exposure of the composite material to UV / visible radiation, the composite surface is often protected by a polymer cover or coated with at least one protective layer, such as, for example, a sprayed-on surfacer or primer layer. The protective layer may, for example, contain a UV "blocking" agent.

[0048]

[0059] Adding UV mitigation or "blocking" agents as layers to composite surfaces often adds manufacturing complexity in ways that at least increase manufacturing time, increase rework time, increase overall production costs, etc., because such applied UV blocking material coverings are typically removed from the composite or chemically or mechanically reactivated before further processing of the composite assembly occurs.

[0049]

[0060] UV / visible light damage from UV / visible light wavelengths that impact composite exposed surfaces and coatings prior to use (e.g., incorporation into an assembly) can cause composites to require material rework. In addition, exposure to UV / visible light radiation can also change material properties over time. For example, UV / visible light radiation can make coating layers or composites vulnerable to processing damage, such as when the layers or composites are exposed to, for example, mechanical paint removal techniques. Selection of material layers for large structures to protect against environmental damage, including UV / visible light damage, can result in the addition of a series of coating layers. Each such coating layer addition can result in significant time, cost, and weight addition to large structures, including, for example, aircraft (which can further affect fuel used, cargo and passenger capacity, aircraft range, etc.).

[0050]

[0061] Disclosed herein are multiple present aspects directed to co-curable and co-cured composites that include a co-curable or co-cured UV / visible light resistant layer in direct contact with a co-curable or co-cured composite substrate. The incorporation of a co-cured and co-curable UV / visible light resistant layer into a composite substrate significantly impacts composite manufacturing, improves performance, and reduces the weight of structural composites by at least eliminating the need to include a separate UV resistant coating that was previously applied to the composite substrate to protect the composite from UV / visible light damage and, for example, in preparation of composite systems used in structural assemblies for larger components, including interior and exterior surfaces of vehicles, including aircraft.

[0051]

[0062] According to further aspects herein, co-curable and co-cured composites incorporating a UV / visible light resistant layer can be co-curable and co-cured composite precursors used in the manufacture of larger assemblies. When such composite assembly precursors are bonded together into larger assemblies, it is desirable to enhance the secondary bonding capabilities of such composite parts. The secondary bonding capabilities of composite parts bonded or glued together can exhibit secondary bonding enhancements by increasing the surface energy (and surface area) of the exposed surfaces. Such increased surface energy (and increased surface area) can be imparted to the composite surfaces, for example, by machining the exposed surfaces to "roughen" the exposed surfaces to which adhesive can be applied. Such additional machining can require significant additional processing and expense. Additionally, such machined surface alterations can be imprecise or can produce non-uniform and random surface alterations on the composite surfaces. Such uneven surface treatments can adversely affect secondary bonding and bond strength at the composite surfaces.

[0052]

[0063] According to some present aspects, during composite assembly precursor fabrication, a co-curable peel ply layer is laminated to an outermost surface of a co-curable (e.g., uncured) composite assembly precursor "stack" so that the entire composite "stack" including the added peel ply layer can be co-cured together in a selected curing regimen. The co-curable peel ply layer includes a fiber and resin system selected to have certain texture and surface characteristics at the peel ply outer surface. The texture and surface characteristics can be selected to be uniform, or can be selected to impart such texture and surface characteristics to the co-curable composite surface on which the peel ply layer is placed and compressed.

[0053]

[0064] According to one embodiment, after co-curing and immediately prior to bonding the composite assembly precursor to another assembly component / part, the co-cured peel ply layer is removed ("peeled") from the co-cured composite assembly precursor to reveal a co-cured composite assembly precursor bond surface. The surface energy of the co-cured composite precursor bond surface is increased to a selected degree through the addition of the co-curable and co-cured peel ply.

[0054]

[0065] The co-curable and co-cured peel ply layers can incorporate dry, unimpregnated sheets of fabric having a selected surface texture. In another aspect, the peel ply layers can incorporate a "wet" pre-impregnated material. This material can be impregnated with a resin-based material that is compatible with the co-curable and co-cured UV / visible light resistant material that is incorporated into the composite substrate and serves to provide a selected amount of UV / visible light protection to the composite substrate. The resin-based material impregnated into the peel ply layer material can be the same or a different UV / visible light resistant resin system as the UV / visible light resistant material incorporated into or on the composite substrate of the composite assembly precursor (e.g., as a separation layer or membrane ply, etc.).

[0055]

[0066] The term "compatible" with respect to the materials in the co-curable and co-cured peel ply layers ("compatible" with the UV / visible light resistant materials in the composite substrate) means that the components of the co-curable and co-cured peel ply layers (which may incorporate a backing layer) are specifically selected so as not to interfere with and not to interfere with the co-curable and co-cured UV / visible light resistant materials during or after co-curing. In other words, the composition of the co-curable and co-cured peel ply layers is configured to at least not interfere with (and preferably enhance or otherwise improve) the selected and resulting secondary bonding properties at the exposed surfaces of the co-cured composite assembly precursors.

[0056]

[0067] Secondary bonding properties may include, for example, a selected physical topography at the composite precursor surface that improves secondary bonding by increasing surface energy, etc. Secondary bonding properties may also include chemical properties of the composite precursor surface that may be imparted, for example, by a UV / visible light resistant material layer disposed at the composite assembly precursor surface designed to improve secondary bonding with a subsequently added adhesive, etc.

[0057]

[0068] According to one present embodiment, the selected surface properties of the co-curable peel ply layer are selected to condition, otherwise alter, and "prepare" the composite surface for significantly improved secondary bonding and co-bonding with surfaces to which the composite will be bonded, co-bonded, adhered, etc., including, for example, bonding the composite assembly precursor of the present disclosure to other structures, in the preparation and manufacture of the composite assembly of the present disclosure, including, for example, the composite assembly precursor of the present disclosure. Additionally, the co-curable and co-cured peel ply layer may protect the composite assembly from exposure to contaminants and / or physical damage, oxidation, etc., which may arise, for example, during manufacture and / or storage, that may weaken the secondary bond in the bond area of ​​the composite assembly precursor.

[0058]

[0069] Additionally, according to some present aspects, selected fiber components of the fiber and resin structures of the co-curable and co-cured peel ply layers are selected to enhance the surface energy of the faying surface of the co-cured composite assembly precursor by creating a selected surface texture and a selected surface area, which properties can be "transferred" from the peel ply layer to the surface of the composite assembly precursor that contacts the peel ply layer.

[0059]

[0070] FIG 1A is a diagram of a vehicle in the form of an aircraft according to several present embodiments. As shown in FIG 1, the aircraft 10 includes a wing assembly 12, a wing assembly fuel tank assembly 13, a horizontal stabilizer assembly 14, and a vertical stabilizer assembly 16. Composite materials of the present disclosure are configured to form or are otherwise configured to form a variety of aircraft assemblies, including those shown in FIG 1A. As further shown in FIG 1A, the aircraft wing assembly 12 includes a vehicle fuel tank in the form of an aircraft fuel tank within the wing assembly (herein referred to as an aircraft wing assembly fuel tank). FIG 1B shows a cross-sectional side view of the wing assembly 13 along line 1B-1B.

[0060]

[0071] As shown in Figure 1B, the aircraft wing assembly fuel tank 13 includes a wing assembly fuel tank exterior surface 13a and a wing assembly fuel tank interior surface 13b. Figure 1B further illustrates a wing assembly fuel tank cavity 13d. The wing assembly fuel tank cavity 13d is defined (e.g., surrounded, bounded) by the aircraft wing assembly fuel tank interior surface 13b. The composite material assembly precursors of the present disclosure may be configured to form or otherwise configured to form a variety of aircraft assemblies, including those shown in Figures 1A and 1B.

[0061]

[0072] According to some present aspects, there is provided a co-curable composite substrate that may include an epoxy resin-based composite material combined with a matrix of fibers that may include carbon fibers, boron fibers, aramid fibers, fiberglass fibers, polyester fibers, and combinations thereof. Carbon fibers are particularly preferred, and co-curable carbon fiber reinforced polymer composites are particularly preferred composite substrates.

[0062]

[0073] According to further aspects of the present disclosure, the co-curable and co-cured composite assembly precursors used in the manufacture of the composite assembly further include a co-curable and co-cured UV / visible light resistant layer (equivalently referred to herein as a UV / visible light suppressive layer). The UV / visible light resistant layer is provided in the composite exclusively in the form of a co-curable UV / visible light resistant layer, which may be, for example, a single co-curable UV / visible light resistant layer ply (e.g., in the form of a single ply film layer) as the co-curable UV / visible light resistant layer.

[0063]

[0074] According to further aspects herein, the co-curable UV / visible light resistant layer includes at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, quartz, and combinations thereof. According to further aspects herein, the co-curable UV / visible light resistant layer is provided in intimate contact with a co-curable composite substrate material. The composite substrate is co-curable with the co-curable UV / visible light resistant layer to form a co-curable UV / visible light resistant coated composite assembly precursor.

[0064]

[0075] According to some present embodiments, a "co-curable" material is defined as a material that can be co-cured with another material, whereby the two co-curable materials will co-cure when exposed to common curing conditions, such as conditions that can be imposed by a predetermined curing regimen (selected temperature, pressure, ramp-up temperature / rate, dwell time, etc.) to form a "co-cured" composition.

[0065]

[0076] The composite substrate, also referred to herein equivalently as a base layer or underlayer or a composite substrate layer, can be an epoxy resin-based material, including a fiber reinforced polymer composite, which can have an epoxy resin-based matrix, and can be a co-curable composite, which can include a carbon fiber reinforced composite. In some present embodiments, the co-curable composite can be any suitable composite that can be co-cured with the co-curable material layer at a temperature ranging from about 250° F. to about 410° F.

[0066]

[0077] Composite materials are often built up into laminates with a selected number of composite plies (often called "prepregs"). Prepregs can be "pre-impregnated" composite fibers with a matrix material already present, such as an epoxy resin-based material. The fibers often take the form of a weave, and a matrix is ​​used to bond them together and with other components during manufacturing. Composite matrix materials are typically partially cured to allow for easy handling. Such composite matrix materials may require cooling or refrigeration to prevent further partial curing or being fully cured, and such composite matrix materials are called B-stage materials. Eventually, B-stage prepregs are stored in a cooled or refrigerated area, since ambient heat can promote complete polymerization. Prepregs can also be impregnated with bulk amounts of fibers and then stored in a cooled or refrigerated area for extended periods of time until later curing. Prepreg plies can be applied to flat or contoured tools, depending on the manufacturing process used. Multiple layers of prepreg plies are used to create the desired shape using a molding or forming tool, also called a mandrel. Several present embodiments contemplate, without limitation, the use of stacked layers of composite prepregs to form co-curable and co-cured composite substrate precursors incorporating compatible enhanced composite surface energy co-curable and co-cured peel ply layers.

[0067]

[0078] According to some present embodiments, a selected degree of UV / visible light resistance and UV / visible light protection may be provided exclusively to the composite substrate after, for example, co-curing the co-curable UV / visible light resistant composite by directly contacting the co-curable composite surface with the co-curable UV / visible light resistant layer. That is, according to some present embodiments, previously required UV / visible light resistant primers, UV blocking paints, and the like may be eliminated or otherwise omitted, since their UV protection function within the UV / visible light resistant composite is fulfilled exclusively by the addition and placement of the co-curable UV / visible light resistant layer provided in direct contact with the co-curable composite substrate.

[0068]

[0079] When used as a precursor that is co-bonded with other composite assembly precursors to form a composite assembly by co-curing the co-curable UV / visible light resistant layer with a co-curable composite material and a selected compatible co-curable and co-cured peel ply layer, multiple advantages are imparted by the co-cured UV / visible light resistant layer of the present disclosure to at least the underlying epoxy-based composite material, as well as the exposed surface properties of the co-cured composite assembly precursor.

[0069]

[0080] According to present embodiments, such benefits provided include, but are not limited to, UV / visible light protection of epoxy-based composites and protection of composite assembly precursors from deleterious surface effects during storage, etc., as well as introducing enhanced surface energy to the final exposed surface of the co-curable UV / visible light resistant composite assembly precursor by applying a compatible co-curable peel ply layer to the exposed surface of the co-curable UV / visible light resistant composite assembly precursor. The compatible co-curable peel ply layer comprises a fiber and resin system that may include a UV / visible light resistant resin and that may be selected to be compatible with the co-curable UV / visible light resistant material incorporated into the co-curable composite assembly precursor to which the peel ply is applied and co-cured.

[0070]

[0081] Through the use of the co-curable and co-cured UV / visible light resistant composite assembly precursors of the present disclosure having compatible peel ply layers, a significant number of otherwise required procedural steps that were previously required are eliminated, resulting in a substantial reduction in resources including, for example, material costs for replacement of UV / visible light damaged layers, manpower hours previously required for additive processing of individual layers (e.g., costs, delays, and processing complexities associated with individual layer surface pre-treatment steps, layer addition steps, layer post-surface processing steps, which include chemical additions, physical surface treatments, e.g., with sand, inspection of deposited layers, etc.).

[0071]

[0082] The co-cured UV / visible light resistant composite assembly precursors are bonded to and integrated within larger composite assemblies. Larger composite assemblies include, for example, aircraft assemblies. Aircraft assemblies include, for example, aircraft wing assemblies. Aircraft wing assemblies may include, for example, stringers. The stringers may be composite stringers or spars. The spars may be composite spars that are co-bonded to a composite skin, or the like. Such composite precursors may be bonded together by, for example, adhering the composite precursors with an intervening adhesive material that may be cured. Exposed surfaces of the composite precursors are typically treated separately to enhance the secondary bonding that occurs at the exposed surfaces. Typical treatments may include separate treatments that significantly increase the surface energy and surface area of ​​the exposed surfaces, but at the same time significantly increase the complexity, cost, weight, etc. of the treatments.

[0072]

[0083] One cost-effective method of increasing the surface energy of exposed composite surfaces involves the use of a protective peel ply layer added to the exposed composite surface. Attempts to co-cure an added co-curable peel ply layer to protect a co-curable composite "stack" with a UV / visible light resistant layer at or near the exposed composite surface have experienced non-uniform results during co-cure. Without being bound to a particular theory, it is believed that the co-curable UV / visible light resistant layer incorporated into the composite was not compatible with the available peel ply layer used to protect the exposed co-curable and co-cured composite surfaces (e.g., from surface damage, discoloration, adverse environmental effects, oxidation, etc.) until use.

[0073]

[0084] Several present aspects are directed to significantly improved co-curable and co-cured UV / visible light resistant composite assembly precursors having compatible peel ply layers, composite assemblies incorporating the present co-cured UV / visible light resistant composite assembly precursors, and methods for making, using, and incorporating the presently disclosed co-curable and co-cured UV / visible light resistant composite assembly precursors into the present composite assemblies.

[0074]

[0085] According to some present embodiments, Figure 2A shows an enlarged cross-sectional representative side view of a co-curable composite precursor "stack" 20 including a co-curable composite substrate 22 with a co-curable UV / visible light resistant layer 24 disposed on the co-curable composite substrate 22. Figure 2A further shows a compatible co-curable peel ply layer 26 disposed on the co-curable UV / visible light resistant layer 24. The co-curable peel ply layer 26 includes a fiber and resin system that is compatible with the co-curable UV / visible light resistant layer 24, such that the co-curable peel ply layer 26 transfers a selected degree of the surface properties of the textured peel ply layer fiber component to the co-curable UV / visible light resistant layer 24. According to several present embodiments, when the peel ply layer is removed from the co-cured co-cured UV / visible light resistant layer 34 (shown in FIG. 2B), a significant increase in the surface energy of the exposed co-cured UV / visible light resistant layer of the cured composite assembly 40 (e.g., as shown in FIG. 2C) is realized.

[0075]

[0086] The co-curable composite material 20 may follow a co-curing regimen, where, for example, the co-curable UV / visible light resistant layer 24, the co-curable composite substrate 22, and the compatible co-curable peel ply layer are co-cured at a cure temperature below 410° F., more preferably at a temperature ranging from about 250° F. to about 410° F., for a period of time suitable to co-cure the components to form a co-cured UV / visible light resistant composite assembly precursor. As shown in FIG. 2A, the co-curable composite substrate 22 may be a co-curable carbon fiber reinforced polymer composite substrate. It may also be a co-curable epoxy resin based composite substrate.

[0076]

[0087] FIG. 2B illustrates a co-cured UV / visible light resistant composite assembly precursor 30 (with compatible co-cured peel ply layer 26 still in place) formed from the uncured components shown in FIG. 2A and now co-cured in a selected co-curing regimen. As shown in FIG. 2B, a co-cured UV / visible light resistant layer 34 is co-cured with the co-cured composite substrate 32 and with the compatible co-cured peel ply layer 36 in place. According to some present embodiments, the co-cured UV / visible light resistant layer 34 can be a single ply or can be two or more plies. The co-cured UV / visible light resistant layer 34 can exclusively provide (i.e., have essentially 100% responsibility for providing) a selected degree of UV / visible light protection to the underlying co-cured composite substrate 32. Thereby, when the co-cured UV / visible light resistant layer has an average thickness in the range of about 2 mils to about 6 mils, for UV / visible light wavelengths in the range of about 180 nm to about 800 nm, the co-cured UV / visible light resistant layer has a UV / visible light transmittance value in the range of about 0% to about 20% UV / visible light transmittance. That is, according to some present embodiments, the UV / visible light blocking ability of the co-cured UV / visible light resistant layer eliminates the need for, makes redundant, or otherwise omits the presence of any additional UV / visible light resistant layers in the composite system. These include, for example, UV / visible light resistant paints, UV / visible light resistant primers, UV / visible light resistant topcoats. As well as, the ability obviates the need to incorporate UV / visible light blocking agents into the composite substrate precursor. Instead, the entire UV / visible light blocking functionality for the co-cured composite precursors of the present disclosure for composite assemblies, and for structures incorporating the co-cured composite assemblies of the present disclosure, may be completely fulfilled by the UV / visible light blocking capabilities introduced into the resulting co-cured composite assembly by a co-curable and co-cured UV / visible light resistant layer, which may be, for example, a single-ply UV / visible light resistant layer. Again, according to this aspect, no additional UV / visible light resistant layer is required to achieve the desired and selected UV / visible light blocking functionality for the co-cured composite assemblies of the present disclosure.

[0077]

[0088] In another example, a selected portion or degree of UV / visible light protection provided to the underlying co-cured composite substrate 32 may be provided or otherwise imparted to the co-cured composite substrate 32 by, for example, a co-curable UV / visible light resistant material impregnated within a fiber matrix within a compatible co-curable peel ply 26 (e.g., a UV / visible light resistant fiber and resin system associated with this peel ply layer applied to an exposed surface of a co-curable composite assembly precursor).

[0078]

[0089] According to some present embodiments, a co-cured UV / visible light resistant composite assembly precursor of the type shown in FIG. 2B (e.g., after removal of the co-cured peel ply layer) can be used as a structural composite precursor for the manufacture of composite assemblies and / or subassemblies, such as structural assemblies and / or subassemblies of vehicles, including aircraft, such as aircraft wing assemblies, aircraft horizontal stabilizers, and aircraft vertical stabilizers, aircraft wing fuel tanks, and the like.

[0079]

[0090] FIG. 2C is an enlarged cross-sectional representative side view of a co-cured UV / visible light resistant composite assembly precursor 40 in the form of a co-cured composite system further including a co-cured UV / visible light resistant composite layer 34 having an exposed surface with a selected surface energy (e.g., surface area) to significantly enhance a selected degree of secondary bonding of the textured composite precursor (e.g., with another composite precursor to form a composite assembly, which may be a structural composite assembly) (as compared to a non-textured exposed composite surface or a textured or non-textured composite surface after co-curing with an incompatible peel ply). That is, FIG. 2C shows a co-cured composite assembly precursor 40 having a co-cured UV / visible light resistant layer 34 disposed on a co-cured epoxy resin composite substrate 32. The co-cured peel ply layer has now been removed and the co-cured composite precursor is now ready for further processing, including, for example, fabrication of a composite assembly incorporating the co-cured composite assembly precursor 40.

[0080]

[0091] FIG. 3 is a partial cross-sectional side view of an exemplary, non-limiting co-curing process of a type useful in making co-cured composite precursors, including a process for making a co-cured composite precursor 130 (similar to the co-cured composite assembly precursor 40 shown in FIG. 2C), which may be, for example, a composite skin. As shown in FIG. 3, a co-curable composite first precursor 110 (e.g., in the form of a co-curable composite "stack") includes a co-curable composite substrate 112, which may be a co-curable carbon fiber reinforced polymer material substrate, which may be a co-curable epoxy resin-based fiber reinforced composite substrate. A co-curable UV / visible light resistant layer 114 is shown disposed over the co-curable composite 112. A co-curable peel ply layer 116 is disposed or otherwise positioned to cover the co-curable UV / visible light resistant layer 114 to form the co-curable composite first precursor 110. The co-curable peel ply layer includes a fiber and resin system selected to be compatible with and further co-curable with the UV / visible light resistant material layer. In a co-curable state, the co-curable composite first precursor may be stored (e.g., in cold storage or refrigeration). The co-curable peel ply layer acts as a protective layer for the composite precursor outer surface during storage in the storage environment.

[0081]

[0092] 3, the co-curable composite first precursor 110 is then introduced into an autoclave 118, where it is exposed to a selected co-cure regimen, such as a co-cure regimen at a temperature ranging from about 250° F. to about 410° F.

[0082]

[0093] After co-curing, the now co-cured composite first precursor 120 includes a co-cured composite substrate 122 including a co-cured region of UV / visible light resistant material 124 covered by a compatible co-cured peel ply layer 126. In the final stage shown in FIG. 3, the co-cured composite first precursor 120 is ready to be incorporated, for example, into a composite assembly. The co-cured peel ply layer 126 can be removed from the co-cured composite first precursor 120 to form a co-cured composite first precursor 130 that now has an exposed outer surface with properties imparted by the compatible peel ply layer (now removed). The imparted surface properties can include, for example, a selected surface energy that can significantly improve secondary bonding at the now exposed surface of the co-cured UV / visible light resistant material layer 124 of the co-cured composite first precursor 130.

[0083]

[0094] 4A is a partial cross-sectional side view of an exemplary, non-limiting co-curing process of a type useful in making and then assembling (e.g., into a composite assembly) the first and second precursors of the co-cured composite material disclosed herein. An exemplary processing protocol for the first precursor of the co-cured composite material 130 (shown in FIG. 3) is again shown in FIG. 4A as an exemplary process to obtain the first precursor of the co-cured composite material assembly 130 (also designated in FIG. 4A as a product or co-cured composite assembly precursor "B", which may be, for example, a composite "skin").

[0084]

[0095] 4A further illustrates an exemplary, non-limiting preparation of a co-curable composite assembly second precursor 140, which is shown, for example, to take the form of a stringer that is combined with "skin," "B" (first precursor) to form a composite assembly 180, which may be, for example, an aircraft wing assembly. As shown in FIG. 4A, a compatible co-curable peel ply is applied to an exposed end of the co-curable composite component 140 (e.g., to be joined with the co-cured composite assembly first precursor 130) to form a co-curable composite assembly second precursor 144. The co-curable composite component 140 and the compatible co-curable peel ply 142 (together forming a co-curable composite assembly second precursor 144) are fed into the autoclave 118 and co-cured according to a selected co-curing regimen to form a co-cured composite assembly second precursor 150 having the compatible co-curable peel ply 152 to form a co-cured composite assembly second precursor 154 (also designated in FIG. 4A as product or composite assembly precursor “A”, which may be, for example, a co-cured composite “stringer”).

[0085]

[0096] Prior to (e.g., immediately prior to, if desired) further processing and combining the first and second composite assembly precursors into a composite assembly, Figure 4A further illustrates removing the co-cured peel ply layer 152 from the second precursor of the composite assembly 154 to form a co-cured composite second precursor 160 now having an exposed outer surface with the surface textured characteristics imparted by the compatible peel ply layer (now removed). The exposed surface of the second precursor includes a selected surface energy that provides the co-cured composite second precursor with a significantly improved bonding surface, for example, at the now exposed surface of the co-cured composite assembly second precursor 160 (also designated in Figure 4A as composite precursor "A").

[0086]

[0097] 4A further illustrates combining precursors A and B together to form a composite assembly formed by interposing an adhesive layer 170 between exposed surfaces of the co-cured composite assembly first precursor 130 and the co-cured composite assembly second precursor 160. After subjecting the bonded composite precursors and adhesive layer to an autoclave 118 for a selected adhesive cure regimen, a finished composite assembly 180 is formed including the composite first precursor 130 and the composite second precursor 160.

[0087]

[0098] In another example, the increased surface area and increased surface energy created on the surfaces of co-curable and / or co-cured composite precursors (e.g., the first precursor shown in FIG. 4A as co-curable composite first precursor 110, specifically without a compatible co-curable peel ply layer) to enhance secondary bonding performance of the precursors in a composite assembly can be achieved in alternative manners beyond the exemplary process shown in FIG. 4A .

[0088]

[0099] As shown in Figure 4B, according to another present embodiment, the first precursor of the co-curable (e.g., uncured) composite material 110a does not include a peel ply layer that is co-curably introduced, particularly prior to assembly of the first precursor 110a with the co-cured second precursor of the composite material 160. That is, as shown in Figure 4B, Figure 4B further illustrates an exemplary, non-limiting preparation of the second precursor of the co-curable composite material assembly 140, which is shown, for example, to take the form of a stringer that is combined with "skin," "B" (first precursor of the composite material) to form a composite material assembly 180, which may be, for example, an aircraft wing assembly.

[0089]

[0100] As shown in FIG 4B, a compatible co-curable peel ply is applied to an exposed surface of the co-curable composite component 140 (e.g., bonded to the first co-curable composite assembly precursor 110a) to form a second co-curable composite assembly precursor 144. The co-curable composite component 140 and the compatible co-curable peel ply 142 (together forming the second co-curable composite assembly precursor 144) are fed into an autoclave 118 and co-cured according to a selected co-curing regimen to form a second co-cured composite assembly precursor 150 having the compatible co-curable peel ply 152 to form a second co-cured composite assembly precursor 154 (also designated in FIG 4B as product or composite assembly precursor "A", which may be, e.g., a co-cured composite "stringer").

[0090]

[0101] Prior to (e.g., immediately prior to, if desired) further processing and combining the first and second composite assembly precursors into a composite assembly, FIG. 4B further illustrates removing the co-cured peel ply layer 152 from the second precursor of the composite assembly 154 to form a co-cured composite second precursor 160 now having an exposed outer surface with the surface textured characteristics imparted by the compatible peel ply layer (now removed). The exposed surface of the second precursor now includes a selected surface energy that provides the co-cured composite second precursor with a significantly improved bonding surface, for example, at the exposed surface of the co-cured composite assembly second precursor 160 (also designated in FIG. 4B as composite precursor "A").

[0091]

[0102] 4B further illustrates combining precursors A and B together to form a composite assembly formed by interposing an adhesive layer 170a between exposed surfaces of the co-cured composite assembly first precursor 110a and the co-cured composite assembly second precursor 160. According to some embodiments, an adhesive layer may be added to one or both of composites "A" and / or "B" as long as the adhesive layer 170 is interposed between the first and second precursor mating surfaces. After subjecting the bonded composite first and second precursors and adhesive layer to an autoclave 118 for a selected adhesive curing regimen, a finished cured composite assembly 180a is formed to include the now cured composite first precursor 110a bonded to the cured composite second precursor 160.

[0092]

[0103] According to some of the present disclosures, the curing and co-curing regimens may be selected to improve the material compatibility and secondary bonding of the first and second composite materials being joined, as well as improve processability of compatible components incorporated into the co-curable peel ply layer, including with respect to compatibility of the peel ply layer with the UV / visible light resistant components and layers incorporated into the first precursor of the composite material.

[0093]

[0104] Such a selected curing regimen may include partial or incomplete curing of the first and second precursors before or after bonding the first and second precursors together (e.g., including bonding the first and second precursors with an intervening adhesive layer). For example, according to some present aspects, as disclosed herein, the first precursor of the co-curable composite material may include a co-curable composite substrate, which may be referred to as a co-curable structural composite substrate. According to some present aspects, as disclosed herein, the first precursor of the co-curable composite material may further include a UV / visible light resistant material layer, which may be equivalently referred to herein as a UV / visible light resistant material surface layer, which may be disposed to substantially completely cover the co-curable composite substrate and may be configured to protect the co-curable composite substrate from, for example, environmentally harmful effects of UV / visible light degradation.

[0094]

[0105] According to some embodiments, at least the first precursor of the co-curable composite may include fibers and a resin system selected to provide the first precursor of the co-curable composite with a resin component in the UV / visible light resistant (surface) layer. The resin component promotes a gel time at a selected gel temperature that is shorter (e.g., faster) than the gel time at the selected gel temperature of the resin system and components incorporated in the co-curable composite substrate underlying the UV / visible light resistant (surface) layer. Some present embodiments contemplate selecting a curing regimen incorporating an initial and subsequent curing regimen, whereby, for example, the UV / visible light resistant (surface) layer is at least partially cured (e.g., during an initial curing stage) prior to at least partially curing the co-curable composite substrate underlying the UV / visible light resistant (surface) layer. Additionally, some present embodiments further contemplate selecting a curing regimen incorporating an initial and subsequent curing regimen. Thereby, for example, during subsequent curing, the UV / visible light resistant (surface) layer is fully cured before fully curing the co-curable composite substrate underlying the UV / visible light resistant (surface) layer.

[0095]

[0106] According to some present aspects, when a selected gel time of the uncured UV / visible light resistant (surface) layer of the first precursor of the composite material is shorter (e.g., faster) than a selected gel time of the composite substrate of the first precursor of the composite material, the uncured UV / visible light resistant (surface) layer may gel faster at a given temperature. That is, the cure reaction rate of the selected resin in the uncured UV / visible light resistant (surface) layer may be relatively faster than the cure reaction rate of the selected resin in the composite substrate of the first precursor of the composite material. The faster gelation of the uncured UV / visible light resistant (surface) layer may further protect the uncured composite substrate layer from at least UV / visible light degradation, etc., by promoting at least partial separation between the cured resin in the UV / visible light resistant (surface) layer and the cured resin in the composite substrate of the first precursor of the composite material.

[0096]

[0107] By selecting varying gel times between component layers within the first precursor of the composite material, the mixing, intermixing, and / or diffusion between the co-curable UV / visible light resistant (surface) layer and the underlying co-curable composite substrate enhances uniformity of selected properties at the exposed surfaces, further promoting improved and selected secondary bonding properties between the first precursor of the composite material and the second precursor of the composite material to form an improved composite assembly.

[0097]

[0108] According to further embodiments, the peel ply layer, including a fiber and resin system that is compatible with the UV / visible light resistant layer at the exposed faying surface of the composite first precursor, can further include a selected amount of a UV / visible light resistant resin material that will be compatible with the UV / visible light resistant layer in the first precursor, both in terms of construction materials and construction material properties, including, for example, gel time and gel temperature. Compatibility of the peel ply layer components with the first precursor material can further strengthen or otherwise enhance secondary bonding at the faying surface of the first and second composite precursors.

[0098]

[0109] According to some present embodiments, FIG. 5 is a flow chart outlining a method for processing a co-curable UV / visible light resistant composite substrate with a compatible peel ply layer to form a co-cured UV / visible light resistant composite precursor for use in a composite assembly. As shown in FIG. 5, the method 200 includes providing 202 a first co-curable composite substrate and applying 204 a co-curable UV / visible light resistant layer onto the first composite substrate. The co-curable UV / visible light resistant layer includes a first co-curable UV / visible light resistant resin. The first co-curable UV / visible light resistant resin can be, for example, an epoxy resin. The co-curable UV / visible light resistant layer further includes at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, quartz, and combinations thereof. The method further includes adding 206 a co-curable peel ply fiber and resin-containing layer adjacent to the co-curable UV / visible light resistant layer to form a first precursor of a co-curable composite assembly. The co-curable peel ply fiber and resin-containing layer further includes a second co-curable UV / visible light resistant resin that is compatible with the co-curable UV / visible light resistant layer and further includes a peel ply backing layer covering the co-curable peel ply fiber and resin-containing layer. The method further includes co-curing 208 a co-curable composite substrate with the co-curable UV / visible light resistant layer and the co-curable peel ply fiber and resin-containing layer to form a first precursor of a co-cured composite for use in, for example, a composite assembly.

[0099]

[0110] In a further aspect, the co-cured UV / visible light resistant layer in the first precursor of the co-cured composite assembly has a UV / visible light transmittance value in the range of about 0% to about 20% UV / visible light transmittance for UV / visible light wavelengths in the range of about 180 nm to about 800 nm when the co-curable UV / visible light resistant layer has an average thickness in the range of about 2 mils to about 6 mils.

[0100]

[0111] 6 is a flow chart outlining a method for making the first and second precursors of the disclosed composite material using a method 300 that includes method 200. Method 300 further includes providing 302 a co-curable second composite substrate and adding 304 a co-curable peel ply fiber and resin-containing layer adjacent to the co-curable second composite substrate to form a co-curable composite second precursor. The co-curable peel ply fiber and resin-containing layer further include a co-curable UV / visible light resistant resin that is compatible with the co-curable UV / visible light resistant layer in a co-cured state, and further includes a peel ply backing layer covering the co-curable peel ply fiber and resin-containing layer. The method 300 further includes co-curing 306 the co-curable second composite substrate with the co-curable peel ply fibers and the resin-containing layer to form a second precursor of a co-cured composite assembly.

[0101]

[0112]

[0031] Figure 7 is a flow chart outlining the manufacture of a composite assembly including co-cured first and second precursors as disclosed herein. As shown in Figure 7, according to method 400, the first and second composite precursors may be formed according to methods 200, 300 as shown and described herein with respect to Figures 5 and 6. The method 400 includes removing 402 a peel ply backing layer from a first precursor of a co-cured composite material to form an exposed surface of a UV / visible light resistant resin layer of the first precursor of a co-cured composite material; removing 404 a peel ply backing layer from a second precursor of a co-cured composite material assembly to form an exposed surface of a second precursor of a co-cured composite material assembly; applying 406 an adhesive layer to at least one of the exposed surface of the UV / visible light resistant resin layer of the first precursor of a co-cured composite material and the exposed surface of the UV / visible light resistant resin layer of the second precursor of a co-cured composite material; and bonding 408 the co-cured first composite material assembly precursor to a co-cured second composite material assembly precursor to form a composite material assembly.

[0102]

[0113] FIG. 8 is a flow chart outlining the manufacture of a composite assembly including co-cured first and second precursors as disclosed herein. As shown in FIG. 8, the method 500 includes providing 202 a first co-curable composite substrate and applying 204 a co-curable UV / visible light resistant layer onto the first composite substrate to form a first precursor of a co-curable composite. The co-curable UV / visible light resistant layer includes a first co-curable UV / visible light resistant resin. The first co-curable UV / visible light resistant resin can be, for example, an epoxy resin. The co-curable UV / visible light resistant layer further includes at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, quartz, and combinations thereof. The method 500 further includes providing 302 a co-curable second composite substrate and adding 304 a co-curable peel ply fiber and resin-containing layer adjacent to the co-curable second composite substrate to form a co-curable composite second precursor. The co-curable peel ply fiber and resin-containing layer further includes a co-curable UV / visible light resistant resin that is co-curable and compatible in a co-cured state with the co-curable UV / visible light resistant layer in the co-curable composite first precursor, and further includes a peel ply backing layer covering the co-curable peel ply fiber and resin-containing layer. The method 500 further includes at least partially co-curing 306 the co-curable second composite substrate with the co-curable peel ply fiber and resin-containing layer to at least partially form a co-cured composite assembly second precursor.

[0103]

[0114] The method 500 further includes removing 404 the peel ply backing layer from the at least partially co-cured second precursor of the composite material assembly to form an exposed surface of the at least partially co-cured second precursor of the composite material assembly; applying an adhesive layer 502 to at least one of the exposed surface of the UV / visible light resistant resin layer of the first precursor of the co-curable composite material and the exposed surface of the UV / visible light resistant resin layer of the at least partially co-cured second precursor of the composite material; bonding 504 the co-curable first composite material assembly precursor to the at least partially co-cured second composite material assembly precursor to form an at least partially cured composite material assembly; and curing 506 the co-curable first composite material precursor to form a cured composite material assembly.

[0104]

[0115] Further present aspects contemplate structures comprising at least one of the co-curable and co-cured composites, assemblies comprising the co-cured composites, subassemblies comprising the co-cured composites, and assemblies and / or subassemblies comprising the co-cured UV / visible light resistant composites made according to the methods described herein, including, for example, manned aerial vehicles, unmanned aerial vehicles, manned spacecraft, unmanned spacecraft, manned rotorcraft, unmanned rotorcraft, manned ground vehicles, unmanned ground vehicles, manned surface vehicles, unmanned surface vehicles, manned underwater vehicles, unmanned underwater vehicles, satellites, and combinations thereof.

[0105]

[0116] As shown in Figures 5, 6, 7 and 8, methods 200, 300, 400, 500 include first and second co-curable composite substrates, which may be co-curable carbon fiber reinforced polymer material substrates and may also be co-curable epoxy resin based fiber reinforced composite substrates, as generally described. According to further aspects herein, one or both of the first and second composite substrates (used to form the first and second precursors) may include a co-curable UV / visible light resistant layer. The co-curable UV / visible light resistant layer may be a co-curable epoxy resin based composite substrate material and may also be a carbon fiber reinforced polymer.

[0106]

[0117] According to some present embodiments, the co-curable UV / visible light resistant layer can be a single ply or multiple plies, whereby the co-curable UV / visible light resistant layer, when cured, has a UV / visible light transmittance value in the range of about 0% to about 20% UV / visible light transmittance for UV / visible light wavelengths in the range of about 180 nm to about 800 nm, when the co-cured UV / visible light resistant layer has an average thickness in the range of about 2 mils to about 6 mils. That is, first and second precursors of co-curable composites, including larger assemblies including compatible peel ply layers and composite assemblies, including vehicles made from the disclosed composite assemblies as shown in Figures 1A, 1B, 2A, 2B, 2C, 3, 4A, and 4B, can be formed and used according to one or more of the methods outlined in Figures 5, 6, 7, and 8.

[0107]

[0118] A co-curable UV / visible light resistant composite including a UV / visible light resistant layer combined with a compatibilly resin-charged co-curable peel ply layer can be a co-curable epoxy resin-based composite substrate. The co-curable UV / visible light resistant layer forms at least a first precursor of a co-cured UV / visible light resistant composite of the type shown and described in Figures 2B, 2C, 3, 4A, and 4B and described herein at a temperature ranging from about 250° F. to about 410° F.

[0108]

[0119] Several present aspects contemplate that the disclosed composite assemblies are useful in the manufacture of vehicles and vehicle assemblies, including, for example, aircraft wing assemblies, horizontal stabilizer assemblies, vertical stabilizer assemblies, fuselages, fuel tanks within wing assemblies, nacelles, and other aircraft structures and structural components that include composite materials.

[0109]

[0120] The present aspects can, of course, be practiced in other ways than as specifically described herein without departing from the essential characteristics of the disclosure. The present aspects are to be considered in all respects as illustrative and non-restrictive, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Claims

1. A co-curable composite assembly precursor (20) (112), Co-curable composite substrate (22)(112) (skin / stack); a co-curable UV / visible light resistant layer (24)(114) disposed adjacent to the composite substrate, the co-curable UV / visible light resistant layer (24)(114) comprising a first co-curable UV / visible light resistant resin and further comprising at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, quartz, and combinations thereof; and 1. A co-curable composite assembly precursor comprising: a co-curable peel ply fiber and resin-containing layer (26)(116) disposed adjacent to the UV / visible light resistant layer, the peel ply fiber and resin-containing layer (26)(116) comprising at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, and combinations thereof, and further comprising a second co-curable UV / visible light resistant resin that is compatible with the co-curable UV / visible light resistant layer.

2. 10. The co-curable composite assembly precursor of claim 1, wherein the co-curable composite substrate is co-curable with the co-curable UV / visible light resistant layer and further co-curable with the co-curable peel ply fiber and resin-containing layer at a temperature in the range of about 250 degrees Fahrenheit to about 410 degrees Fahrenheit.

3. The co-curable composite assembly precursor of claim 1 , wherein the co-curable composite substrate comprises a carbon fiber reinforced polymer.

4. 10. The co-curable composite assembly precursor of claim 1, wherein the co-curable composite substrate comprises an epoxy resin-based compound and further comprises at least one of carbon fibers, boron fibers, aramid fibers, fiberglass fibers, polyester fibers, and combinations thereof.

5. The co-curable composite assembly precursor of claim 1 , wherein the co-curable composite substrate comprises a plurality of carbon fiber reinforced polymer prepregs.

6. 2. The co-curable composite assembly precursor of claim 1, wherein the second side of the co-curable composite substrate is in direct contact with the co-curable UV / visible light resistant layer, and the co-curable UV / visible light resistant layer completely covers the second side of the co-curable composite substrate.

7. A composite material assembly precursor (30) (120) to be co-cured, a composite substrate (32) (122) to be co-cured; a co-cured UV / visible light resistant layer (34)(124) disposed adjacent to the first composite substrate, the co-cured UV / visible light resistant layer (34)(124) comprising a first co-curable UV / visible light resistant resin and further comprising at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, quartz, and combinations thereof; a co-cured peel ply fiber and resin-containing layer (36)(126) disposed adjacent to the co-cured UV / visible light resistant layer, the co-cured peel ply fiber and resin-containing layer (36)(126) comprising at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, and combinations thereof, and further comprising a second co-cured UV / visible light resistant resin that is compatible with the co-cured UV / visible light resistant layer; when the co-cured UV / visible light resistant layer has an average thickness in the range of about 2 mils to about 6 mils, for UV / visible light wavelengths in the range of about 180 nm to about 800 nm, the co-cured UV / visible light resistant layer has a UV / visible light transmittance value in the range of about 0% to about 20% UV / visible light transmittance; The co-cured composite substrate is co-cured with the co-cured UV / visible light resistant layer at a temperature ranging from about 250°F to about 410°F and is further co-curable with the co-cured peel ply fiber and resin-containing layer, a co-cured composite assembly precursor.

8. 8. The co-cured composite assembly precursor of claim 7, wherein the co-cured composite substrate comprises an epoxy resin based compound and further comprises at least one of carbon fibers, boron fibers, aramid fibers, fiberglass fibers, polyester fibers, and combinations thereof.

9. The co-cured composite assembly precursor of claim 7 , wherein the co-cured composite substrate comprises a plurality of carbon fiber reinforced polymer prepregs.

10. A co-curable composite assembly precursor (144), comprising: a co-curable composite substrate (140) (stringer); a co-curable peel ply fiber and resin-containing layer (142) disposed adjacent to the co-curable composite substrate, the co-curable peel ply fiber and resin-containing layer further comprising a co-curable UV / visible light resistant resin.

11. The co-curable composite assembly precursor of claim 10 , wherein the co-curable composite substrate comprises a carbon fiber reinforced polymer.

12. 11. The co-curable composite assembly precursor of claim 10, wherein the co-curable composite substrate comprises an epoxy resin based compound and further comprises at least one of carbon fibers, boron fibers, aramid fibers, fiberglass fibers, polyester fibers, and combinations thereof.

13. The co-curable composite assembly precursor of claim 10 , wherein the co-curable composite substrate comprises a plurality of carbon fiber reinforced polymer prepregs.

14. A co-cured composite assembly precursor (154), comprising: a co-cured composite substrate (150) (stringer); a co-cured peel ply fiber and resin-containing layer (152) disposed adjacent to the co-cured composite substrate, the co-cured peel ply fiber and resin-containing layer further comprising a co-cured UV / visible light resistant resin.

15. The co-cured composite assembly precursor of claim 14 , wherein the co-cured composite substrate comprises a carbon fiber reinforced polymer.

16. 15. The co-cured composite assembly precursor of claim 14, wherein the co-cured composite substrate comprises an epoxy resin-based compound and further comprises at least one of carbon fibers, boron fibers, aramid fibers, fiberglass fibers, polyester fibers, and combinations thereof.

17. The co-cured composite assembly precursor of claim 14 , wherein the co-cured composite substrate comprises a plurality of carbon fiber reinforced polymer prepregs.

18. A method (200) (for making a "first" precursor of a co-cured composite assembly by adding a peel ply to a skin / stack), comprising: Providing a first co-curable composite substrate (202); applying a co-curable UV / visible light resistant layer over the first co-curable composite substrate (204), the co-curable UV / visible light resistant layer comprising a first co-curable UV / visible light resistant resin and further comprising at least one of fiberglass fibers, carbon fibers, polyester fibers, aramid fibers, boron fibers, quartz, and combinations thereof; adding (206) a co-curable peel ply fiber and resin-containing layer adjacent to the co-curable UV / visible light resistant layer to form a first precursor of a co-curable composite assembly, the co-curable peel ply fiber and resin-containing layer further comprising a second co-curable UV / visible light resistant resin that is compatible with the co-curable UV / visible light resistant layer, and a peel ply backing layer covering the co-curable peel ply fiber and resin-containing layer; and co-curing (208) the co-curable composite substrate with the co-curable UV / visible light resistant layer and the co-curable peel ply fiber and resin-containing layer to form a first precursor of a co-cured composite assembly.

19. 20. The method of claim 18, wherein the first precursor of the co-cured composite assembly comprises a co-curable UV / visible light resistant layer having a UV / visible light transmittance value in the range of about 0% to about 20% UV / visible light transmittance for UV / visible light wavelengths in the range of about 180 nm to about 800 nm when the co-curable UV / visible light resistant layer has an average thickness in the range of about 2 mils to about 6 mils.

20. The method of claim 18 , wherein the co-curable UV / visible light resistant layer is applied to the co-curable composite substrate as a single ply.

21. The method of claim 18 , wherein the co-curable composite substrate comprises a carbon fiber reinforced polymer composite substrate.

22. 20. The method of claim 18, wherein the co-curable composite substrate comprises a fiber reinforced epoxy resin matrix, the fiber reinforced epoxy resin matrix comprising at least one of carbon fibers, boron fibers, aramid fibers, fiberglass fibers, polyester fibers, and combinations thereof.

23. A first precursor (30) (124) of a co-cured composite assembly made according to the method of claim 18.

24. 20. A method (300) (for making a "second" stringer precursor of a co-cured composite assembly by adding a peel ply to a stringer) as recited in claim 18, comprising: Providing a second co-curable composite substrate (302); adding (304) a co-curable peel ply fiber and resin-containing layer adjacent to the co-curable second composite substrate to form a second co-curable composite precursor, the co-curable peel ply fiber and resin-containing layer further comprising a second co-curable UV / visible light resistant resin that, in a co-cured state, is compatible with the co-curable UV / visible light resistant layer in the first co-curable composite substrate, and a peel ply backing layer covering the co-curable peel ply fiber and resin-containing layer; and co-curing (306) the co-curable second composite substrate with the co-curable peel ply fibers and resin-containing layer to form a second precursor of a co-cured composite assembly.

25. A second precursor (30) (154) of a co-cured composite assembly made according to the method of claim 24.

26. 25. The method (400) of claim 24, comprising: removing the peel ply backing layer from the first precursor of a co-cured composite assembly to form an exposed surface of a UV / visible light resistant resin layer of the first precursor of a co-cured composite assembly (402); removing the peel ply backing layer from the second precursor of the co-cured composite assembly to form an exposed surface of a UV / visible light resistant resin layer of the second precursor of the co-cured composite assembly (404); applying an adhesive layer to at least one of an exposed surface of the UV / visible light resistant resin layer of a first precursor of the co-cured composite assembly and an exposed surface of the UV / visible light resistant resin layer of a second precursor of the co-cured composite assembly (406); and The method further comprises bonding (408) a first precursor of the co-cured composite assembly to a second precursor of the co-cured composite assembly to form a composite assembly (13) (180).

27. 27. A composite assembly (13) (180) made according to the method of claim 26.

28. A vehicle (10) comprising a composite material assembly according to claim 27.

29. An aircraft (10) comprising a composite material assembly according to claim 27.

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