Composite component for an aircraft, method of forming a composite component for an aircraft, outlet guide vane structure for an aircraft and aircraft

Abstract

The present invention relates to a composite component (130) for an aircraft, including: a first end (131); a second end (132); a body portion (133) having a first conductivity; a conductive portion (134) having a second conductivity, wherein the second conductivity is higher than the first conductivity; wherein the conductive portion (134) includes pitch carbon fibers, graphene, or one or more metal fibers (135), and extends from the first end (131) to the second end (132). The present invention also relates to a method (100) of forming the composite component (130) including: forming (702) the body portion (133); adding (702) a conductive portion (134) during forming of the body portion (133), the conductive portion (134) including pitch carbon fibers, graphene, or one or more metal fibers (135). The present invention further relates to an outlet guide vane structure for an aircraft including the composite component (130), as well as to an aircraft including the composite component (130).

Description

[0001] Composite Component

[0002] Technical Field and Background

[0003] The present invention is concerned with composite components for aircraft applications. Specifically, the present invention is concerned with composite components that provide lighting strike protection and / or de-icing capabilities.

[0004] An aircraft may experience adverse weather conditions during flight. This may result in the aircraft being struck by lightning. A lightning strike may cause damage to the aircraft components and / or the internal systems of the aircraft. Aircraft are equipped with lightning strike protection systems that conduct and dissipate the electrical energy from the lightning strike along a particular path through the aircraft. This may be achieved by the addition of a metallic grounding strip which is embedded in the composite component and requires bolts for connection to the fittings. The metallic grounding strip forms part of a conductive path through the aircraft. When lightning strikes the component, the electrical energy is conducted through the metallic grounding strip and away from the internal systems and / or other components which may be damaged by the lightning strike. This reduces the impact of lightning strikes on the aircraft.

[0005] However, this arrangement is not robust. It can be difficult to ensure contact between the bolt and the metallic grounding strip, which may cause damage to the composite component. Close tolerance bolts are required, as well as machined bolt-holes with tight tolerances. This makes manufacturing, repair and maintenance of the composite component complex. In addition, machining issues may be experienced due to the different materials of the grounding strip and the composite component. The metallic grounding strip and the composite component also have different thermal expansion coefficients, and expand and contract at different rates. This can lead to fatigue of the component. The metallic grounding strip is also bulky and adds weight to the composite component.

[0006] Conductivity of the component is measured in the final assembly, which is difficult to correct. Specifically, the conductivity is dependent on the electrical contact between the fittings, the bolts and the metallic grounding strip. It is therefore difficult to measure the conductivity until the component has been assembled.

[0007] An aircraft may experience low temperatures during flight. In the presence of moisture, aircraft components may experience a build-up of ice on their surface during flight. This may affectthe performance of the component. De-icing systems may be provided to prevent and reduce the build-up of ice on aircraft components, typically by providing heat to prevent the formation of ice or to melt ice that is already present. De-icing systems are typically provided as a separate system to the lightning strike protection.

[0008] The inventors have discovered a new and counterintuitive way of providing robust lightning strike protection whilst also preventing the build-up of ice on aircraft components. Thus a single component is provided which achieves both these functions.Summary of the Invention

[0009] Aspects of the invention are set out in the accompanying claims.

[0010] According to a first aspect of the invention, there is provided a composite component for an aircraft, comprising: a first end; a second end; a body portion having a first conductivity; and a conductive portion having a second conductivity. The second conductivity is higher than the first conductivity. The conductive portion comprises pitch carbon fiber, graphene, or one or more metal fibers, and extends from the first end to the second end.

[0011] The composite component described herein advantageously comprises a conductive portion comprising pitch carbon fiber, graphene, or one or more metal fibers. This conductive portion with the second, higher, conductivity provides lightning strike protection for the composite component. By providing a conductive portion comprising (or formed from) pitch carbon fiber, graphene or one or more metal fibers, a part is provided that is robust and does not require machining or tight tolerance bolts.

[0012] As pitch carbon fiber, graphene or one or more metal fibers are used, the difference in properties between the lighting strike protection and the body portion of the composite component is reduced. This reduces fatigue of the component. In addition, the lightning strike protection provided by pitch carbon fiber, graphene or one or more metal fibers that can be formed integrally with the body portion of the composite component, as opposed to inserting a metallic grounding strip within the component and using a bolt for connection to the fittings. Machining and tight tolerance bolts are therefore not required in order to form a conductive path through the composite component. The conductivity of the component can be more precisely controlled compared to conventional components. This is because the conductivity of the component does not depend on the electrical contact of the bolts and fittings, as bolts and fittings are not required.

[0013] The conductive portion may comprise one or more of pitch carbon fiber, graphene, and / or one or more metal fibers.

[0014] The phrase ‘integrally formed’ may refer to components which are connected together so as to make up a single piece that cannot be dismantled without destroying the integrity of the piece or its components. In other words, the components cannot be separated without damaging the components. The conductive portion may be integrally formed within the body portion, or integrally formed proximate to an outer surface of the body portion.The conductive portion and the body portion may therefore be formed as a single piece, and / or form a single part; additional components such as bolts to attach the conductive portion and the body portion are not required. In this way, the conductive portion may be integral with the body portion.

[0015] The phrase ‘extends from the first end to the second end’ may refer to the conductive portion extending across a whole length of the body portion from the first end to the second end. This phrase may also refer to the conductive portion extending across a portion of the length of the body portion from the first end to the second end. This phrase may also refer to the conductive portion extending across a majority of the length of the body portion from the first end to the second end.

[0016] The body portion and the conductive portion may be impregnated with resin. Impregnating the body portion and conductive portion with resin may comprise adding resin to the body portion and conductive portion. Impregnating the body portion and the conductive portion with resin may improve the mechanical properties of the component. In examples, impregnating the body portion and the conductive portion with resin may also bind the body portion and the conductive portion together, such that the body portion and the conductive portion are integrally formed as a single part. The resin may be epoxy resin or polymer resin. High-temperature polymer resin is particularly advantageous for de-icing systems, as it can maintain its structural integrity at high temperatures.

[0017] The conductive portion may extend within the body portion. The body portion may comprise a plurality of layers of a first material, and the conductive portion may be arranged between two layers of the first material. The conductive portion may be formed from a second material that has a higher conductivity than the first material. The conductive portion extending within the body portion advantageously provides protection to the conductive portion, preventing erosion and impact damage.

[0018] The conductive portion may be proximate to an outer surface of the composite component. The conductive portion may be closer to an outer surface of the composite component than to the centre of the composite component. The conductive portion being proximate to an outer surface of the composite component advantageously provides effective de-icing capabilities, as heat can be effectively transferred from the conductive portion to the surface of the composite component.The composite component may comprise one or more glass fibers extending along a surface of the body portion. The one or more glass fibers may extend along part of a surface of the body portion. The one or more glass fibers may extend along the whole length of a surface of the body portion. The one or more glass fibers may cover a region of the surface area of the body portion, or may cover the whole surface area of the body portion. The one or more glass fibers advantageously protect the body portion from debris and erosion.

[0019] The composite component may comprise a vane. The composite component may comprise a guide vane. The composite component may comprise an outlet guide vane, or an inlet guide vane. It is advantageous to provide lightning strike protection in aircraft vanes, such as outlet guide vanes or inlet guide vanes, as these components commonly experience lightning strikes. Furthermore, providing lightning strike protection in the outlet guide vanes advantageously provides an effective conductive path through the aircraft between the engine core and the outer casing, avoiding fragile components and internal systems which may otherwise be damaged as a result of the lightning strike.

[0020] The conductive portion may be proximate to the leading edge and / or trailing edge of the vane. The conductive portion may be at the leading edge and / or the trailing edge of the vane. The leading edge of the vane is more likely to experience lightning strikes, therefore it is advantageous to provide the conductive portion at or proximate to the leading edge of the vane. Locating the conductive portion at or proximate to the trailing edge of the vane is advantageous as the trailing edge of the vane is less likely to experience impact damage from debris entering the engine. Therefore, the conductive portion is less likely to be damaged.

[0021] The composite component may comprise a flange. The composite component may be a wing leading edge flange, an engine inlet flange, a propeller flange or a rotor flange. The flanges in an aircraft are prone to ice-build up, therefore it is advantageous to provide de-icing capabilities in the flanges. It is advantageous to provide lightning strike protection in the flanges, as the flanges may form part of a conductive path to conduct electrical energy through the aircraft.

[0022] The conductivity may be an electrical conductivity and / or a thermal conductivity. The conductive portion having an electrical conductivity that is higher than the electrical conductivity of the body portion is advantageous for lightning strike protection. The conductive portion having a thermal conductivity that is higher than the thermal conductivity of the body portion is advantageous for de-icing capabilities. The conductive portion having an electrical conductivity and a thermal conductivity that is higher than the electrical conductivity and thethermal conductivity of the body portion advantageously provides effective de-icing capabilities and effective lightning strike protection.

[0023] The body portion may comprise carbon fiber. Specifically, the body portion may be formed of carbon fiber. Carbon fiber is advantageous for aircraft applications due to its high strength and light weight.

[0024] The body portion may comprise PAN carbon fiber. PAN (or PAN based) carbon fiber is a polyacrylonitrile-based carbon fiber, and is particularly advantageous for aircraft applications as it has a high strength-to-weight ratio.

[0025] The conductive portion may comprise pitch carbon fiber. Pitch carbon fiber is a type of carbon fiber that is produced from pitch (a viscoelastic polymer). Pitch advantageously has a high electrical and thermal conductivity, providing effective lightning strike and de-icing capabilities. Pitch carbon fiber is also lightweight, therefore lighting strike protection and / or de-icing capabilities can be provided without substantially affecting the weight of the composite component. Pitch carbon fiber is brittle, and is therefore not commonly used in composite components. The inventors have devised that the limitations of pitch carbon fiber can be reduced by integrally forming the pitch carbon fiber conductive portion with the body portion, or arranging the pitch carbon fiber conductive portion within the body portion.

[0026] The conductive portion may comprise graphene. The conductive portion may be doped with graphene. Graphene doping may refer to adding graphene to a material to improve the properties of the material. Graphene advantageously provides high conductivity for effective lightning strike protection and / or de-icing capabilities. The use of graphene also provides a reduced difference in material properties between the conductive portion and the body portion compared to other materials. The component is therefore less prone to fatigue caused by differing thermal expansion coefficients of the conductive portion and the body portion.

[0027] The conductive portion may comprise one or more metal fibers. This advantageously provides high conductivity for effective lightning strike protection and / or de-icing capabilities. In examples, the conductive portion comprises a plurality of metal fibers or a metal mesh. The one or more metal fibers are advantageously less bulky and provide less weight than existing lightning strike protection. The one or more metal fibers also reduce the damage caused to the composite component by thermal expansion in comparison to existing lightning strike protection.The conductive portion may comprise one or more metal fibers extending in a first direction. This advantageously provides high conductivity across the composite component in a first direction, providing effective lightning strike protection and / or de-icing capabilities.

[0028] The conductive portion may comprise one or more metal fibers extending in a second direction substantially perpendicular to the first direction. This advantageously allows the fibers extending in the first direction to form a first circuit in a first direction, and the fibers extending in the second direction to form a second circuit in a second direction. The first circuit may be separate and / or isolated from the second circuit. The first circuit may provide effective de-icing capabilities, and the second circuit may provide effective lightning strike protection. Advantageously, the first circuit and the second circuit may be individually configured or tuned for their specific application, so the composite component provides effective lightning strike protection and effective de-icing capabilities.

[0029] The one or more metal fibers extending in the first direction may be longer than the one or more metal fibers extending in the second direction. Longer fibers experience greater resistance in comparison to shorter fibers. Therefore, longer fibers are more effective at generating heat and are advantageous in de-icing applications. Shorter fibers can conduct electricity more effectively, and are more effective for lightning strike protection. Therefore, providing a first circuit with longer metal fibers advantageously provides a high resistance circuit for effective de-icing. Providing a second circuit with shorter metal fibers advantageously provides a lower resistance circuit for effective lighting strike protection. By providing both circuits, the composite component advantageously provides improved de-icing capabilities in addition to improved lightning strike protection.

[0030] The one or more metal fibers may comprise copper fibers. Copper fibers advantageously have a high conductivity for effective lightning strike protection and / or effective de-icing capabilities.

[0031] The one or more metal fibers may extend through a depth of the conductive portion. The depth of the conductive portion may refer to any direction that is orthogonal to the direction extending between the first end and the second end of the composite component. The one or more metal fibers may partially extend through the depth of the conductive portion, or may extend through the full depth of the conductive portion. The one or more metal fibers extending through the depth of the conductive portion advantageously provides high conductivity through the depth of the conductive portion, providing effective lighting strike and / or de-icing capabilities. This also advantageously improves the strength of the conductive portion, improving impact resistance and longevity of the component.The one or more metal fibers may be coated with a non-corrosive material. Metal fibers may be prone to galvanic corrosion when in contact with other materials, in particular carbon fiber. The inventors have devised that the metal fibers may be coated with a non-corrosive material. This advantageously prevents corrosion of the metal fibers, improving the longevity of the component.

[0032] According to a second aspect of the invention, there is provided a method of forming the composite component of the first aspect, comprising: forming the body portion; adding a conductive portion during forming of the body portion, the conductive portion comprising pitch carbon fiber, graphene, or one or more metal fibers.

[0033] The method described herein advantageously forms the lightning strike protection and / or the de-icing system as part of the composite component as the component is being formed, resulting in a component with built-in lightning strike protection and / or de-icing capabilities. This removes or reduces the problems associated with inserting an additional component for lightning strike protection (for example, a metallic grounding strip) within the composite component. Robust lightning strike protection can therefore be provided, and machining and tight tolerance bolts are not required. The manufacturing process also advantageously requires fewer steps, as the machining and bolt attachment is not required. The difference in properties between the lightning strike protection and the body portion is also reduced by the use of pitch carbon fiber, graphene or one or more metal fibers. This reduces fatigue of the resulting composite component.

[0034] The method may further comprise impregnating the body portion and the conductive portion with resin. Impregnating the body portion and conductive portion with resin may comprise adding resin to the body portion and conductive portion. Impregnating the body portion and the conductive portion with resin may improve the mechanical properties of the component. Impregnating the body portion and the conductive portion with resin may also bind the body portion and the conductive portion together, allowing the body portion and the conductive portion to be integrally formed as a single part.

[0035] Adding the conductive portion may comprise arranging the conductive portion within the body portion. The body portion may comprise a plurality of layers of a first material. The method may comprise laying one or more layers of a first material, inserting a conductive portion between two layers of the first material. The conductive portion may be formed from a second material that has higher conductivity than the first material. The conductive portion extendingwithin the body portion advantageously provides protection to the conductive portion, preventing erosion and impact damage.

[0036] According to a third aspect of the invention, there is provided an outlet guide vane structure for an aircraft comprising the composite component described herein. Outlet guide vanes commonly experience lighting strikes and are also prone to ice-build up. Therefore, it is advantageous to provide lighting strike protection and de-icing capabilities on an outlet guide vane.

[0037] According to a fourth aspect of the invention, there is provided an aircraft comprising the composite component described herein. Aircraft commonly experience lightning strikes which can damage aircraft components. Aircraft components also commonly experience ice buildup, which can affect the performance of the components. Therefore, an aircraft comprising the composite component described herein is advantageously less prone to damage from lightning strikes and ice build-up.Brief Description of the Drawings

[0038] One or more embodiments of the invention will now be described, by way of example only, and with reference to the following figures in which:

[0039] Figure 1 shows a schematic view of a cross-section of a geared turbo fan engine comprising a composite component according to examples of the present disclosure;

[0040] Figure 2 shows a schematic view of a cross-section of a composite component in a first direction according to examples of the present disclosure;

[0041] Figure 3 shows a schematic view of a cross-section of a composite component in a second direction according to examples of the present disclosure;

[0042] Figure 4 shows a schematic view of a cross-section of a composite component in a second direction according to examples of the present disclosure;

[0043] Figure 5 shows a schematic view of a conductive portion according to examples of the present disclosure;

[0044] Figure 6 shows a schematic view of a conductive portion according to examples of the present disclosure;

[0045] Figure 7 shows a flow chart of a method for forming a composite component according to examples of the present disclosure;

[0046] Figure 8 shows a schematic view of a process for forming a composite component according to examples of the present disclosure;

[0047] Any reference to prior art documents in this specification is not to be considered an admission that such prior art is widely known or forms part of the common general knowledge in the field. As used in this specification, the words “comprises”, “comprising”, and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean “including, but not limited to”. The invention is further described with reference to the following examples. It will be appreciated that the invention as claimed is not intended to be limited in any way by these examples. It will also be recognised that the invention covers not only individual embodiments but also combination of the embodiments described herein.The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and / or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and / or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the spirit and scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc., other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.Detailed

[0048] The composite component described herein advantageously has lightning strike protection comprising pitch carbon fiber, graphene or one or more metal fibers. Lightning strike protection can therefore be provided without the requirement of machining or tight tolerance bolts, reducing the complexity of the manufacturing process and improving ease of maintenance and repair. The composite component is also more robust and less prone to fatigue, and the manufacturing process requires fewer steps.

[0049] The composite component described herein is particularly advantageous in aircraft applications, where damage caused by lightning strikes and ice-build up is common. The composite component may advantageously comprise a vane or flange. The composite component may advantageously be any other component that experiences lightning strikes and / or ice-build up.

[0050] Figure 1 shows a schematic view of a cross section through a geared turbo fan engine 100 comprising a composite component 130 according to examples of the present disclosure. In the example shown in Figure 1, the composite component 130 is an outlet guide vane for an aircraft.

[0051] The operation of a geared turbo fan engine will be understood by a person skilled in the art of engine design. However, for clarity, in the present application the engine 100 comprises a central core 120 centred about a central axis 140 of the engine 100. The engine core comprises a forward facing portion which rotates and supports radially extending fan blades 110. The fan blades 110 and the outlet guide vane 130 extend within the bypass channel 160 in between the core 120 and the bypass channel wall 150.

[0052] Figures 2 to 4 show the composite component 130 as a vane. Figure 2 shows a schematic view of a cross-section of the vane 130 in a first direction according to examples of the present disclosure. As shown in Figure 2, the vane 130 comprises a first end 131, a second end 132, a body portion 133 having a first conductivity, a conductive portion 134 having a second conductivity, wherein the second conductivity is higher than the first conductivity, and wherein the conductive portion 134 extends from the first end 131 to the second end 132. The conductive portion 134 comprises pitch carbon fiber, graphene, or one or more metal fibers.

[0053] In the example shown in Figure 2, the conductive portion 134 extends across the full length of the body portion 133, from the first end to the second end 132. The conductive portion mayalternatively partially extend across the body portion in a direction from the first end 131 to the second end 132. The conductive portion 134 may alternatively extend across the majority of the length of the body portion 133 from the first end 131 to the second end 132.

[0054] The phrase ‘integrally formed’ may refer to components which are connected together so as to make up a single piece that cannot be dismantled without destroying the integrity of the piece or its components. In other words, the components cannot be separated without damaging the components.

[0055] The body portion 133 may refer to the main structure of the vane 130. The body portion 133 may be the part of the vane 130 that is configured to provide the main function of the vane 130. In some examples (as shown in Figure 4), the body portion 133 may refer to all the parts of the vane 130 excluding the conductive portion 134.

[0056] The conductive portion 134 may refer to a portion that provides lightning strike and / or de-icing capabilities to the vane 130.

[0057] The conductivity may be an electrical conductivity and / or a thermal conductivity. When the conductivity is an electrical conductivity, the conductive portion 134 has a higher electrical conductivity than the body portion 133. The conductive portion 134 forms part of a conductive path through the engine 100 which may be configured to avoid the internal systems and / or other aircraft components which may be damaged by the lightning strike. When lightning strikes the vane 130, electrical energy from the lightning strike is conducted through the conductive portion 134 of the vane 130 and along a conductive path where it is then dissipated.

[0058] When the conductivity is a thermal conductivity, the conductive portion 134 has a higher thermal conductivity than the body portion 133. Therefore, the conductive portion 134 is effective at transferring heat to the vane 130. This is advantageous for de-icing applications, as heat can easily be transferred to the vane 130 to melt the ice and / or prevent ice build-up.

[0059] Higher electrical conductivity of the conductive portion 134 may also result in higher thermal conductivity of the conductive portion 134. This is dependent on the type of material used in the conductive portion 134.

[0060] The first conductivity is dependent on the type of material used for the body portion 134. The body portion 133 may comprise carbon fiber. The body portion 133 may comprise PAN (or PAN-based) carbon fiber. PAN (or PAN-based) carbon fiber may refer to carbon fiber thatcomprises Polyacrylonitrile. Other types of carbon fiber may be used depending on the type of vane 130. For example, Rayon based or bio-based carbon fibers (such as lignin) may be used.

[0061] When the body portion 133 comprises PAN carbon fiber, the first conductivity may be within the range 102to 104S / m (electrical conductivity) or 5 to 20 W / m°K (thermal conductivity). This corresponds to a resistivity of 0.1 to 1x10-3Q cm.

[0062] The first conductivity may be, for example, about 76.9x103S / m (electrical conductivity) or about 11.3 W / m°K (thermal conductivity). This corresponds to a resistivity of 1.3 x10'3Q cm. The first conductivity may be about 58.8x103S / m (electrical conductivity) or about 6.8 W / m°K. (thermal conductivity). This corresponds to a resistivity of 1.7 x10'3Q cm.

[0063] The first conductivity may be less than 104S / m (electrical conductivity) or less than 20 W / m K (thermal conductivity).

[0064] The second conductivity is dependent on the type of material used for the conductive portion 134. The conductive portion 134 has a higher conductivity than the body portion 133. The conductive portion 134 may comprise pitch (or pitch-based) carbon fiber. Pitch (or pitch-based) carbon fiber may refer to a viscoelastic material comprising hydrocarbons.

[0065] Additionally or alternatively, the conductive portion 134 may comprise graphene and / or one or more metal fibers. This may increase the conductivity of the conductive portion 134.

[0066] The second conductivity may be greater than 104S / m (electrical conductivity) or greater than 20 W / m°K (thermal conductivity).

[0067] The body portion 133 and the conductive portion 134 may be impregnated with resin, which may further enhance the properties of the composite component. The resin may be epoxy resin or polymer resin. Where the composite component is impregnated with resin, the above values of the conductivities correspond to the conductivity before the composite component is impregnated with resin.

[0068] Figure 3 shows a schematic view of a cross-section of the vane 130 in a second direction according to examples of the present disclosure. Figure 3 shows a cross-section of the composite component taken about the line X shown in Figure 2.

[0069] As shown in Figure 3, the conductive portion 134 may extend within the body portion 133. The conductive portion 134 may be arranged inside the body portion 134. In the example shown in Figure 3, the cross-section of the conductive portion 134 is triangular shaped, however theconductive portion 134 may be any shape. For example, the cross-section of the conductive portion 134 may be square, rectangular, circular, or hexagonal. The conductive portion 134 may comprise a mesh.

[0070] The conductive portion 134 may be proximate to an outer surface of the composite component 130. The conductive portion 134 may be arranged relatively close to an outer surface of the vane 130 compared to the centre of the component. The conductive portion 134 may be proximate to the suction surface and / or a pressure surface of the vane 130.

[0071] The proximity of the conductive portion 134 to the outer surface of the composite component may be dependent on the type of composite component, the material used for the body portion, the material used for the conductive portion, and the desired application of the component (for example, de-icing and / or lightning strike protection). Alternatively, the conductive portion 134 may be arranged within the outer 10% of the composite component, or within the outer 20%, 30% 40% or 50% of the composite component.

[0072] In the example shown in Figure 3, the conductive portion 134 is proximate to the leading edge of the vane 130. The conductive portion 134 may additionally or alternatively be proximate to the trailing edge of the vane 130.

[0073] Figure 4 shows a schematic view of a cross-section of a vane 130 in a second direction according to examples of the present disclosure. As shown in Figure 4, the conductive portion 134 is proximate to an outer surface of the body portion 133. In the example shown in Figure 4, the conductive portion 134 extends along part of the body portion 133. The conductive portion 134 may extend along the majority or the whole of the body portion 133.

[0074] In the example shown in Figure 4, the conductive portion 134 is proximate to the suction surface of the vane 130. The conductive portion 134 may additionally or alternatively be proximate to the pressure surface of the vane 130. The conductive portion 134 may be proximate to the leading edge and / or the trailing edge of the vane 130.

[0075] The vane 130 may comprise one or more glass fibers 136 extending along the surface of the body portion. The one or more glass fibers 136 may extend partially along a region of the surface of the body portion 133, or may extend along a whole length of a surface of the body portion 133. The one or more glass fibers 136 may extend across part of the surface area of the body portion 133, or may extend across the whole area of a surface of the body portionFigure 5 shows a schematic view of a conductive portion 134 according to examples of the present disclosure. As shown in the example in Figure 5, the conductive portion 134 may comprise one or more metal fibers 135. The conductive portion 134 may comprise a plurality of metal fibers 135. The one or more metal fibers 135 advantageously increases the conductivity of the conductive portion 134, therefore the conductive portion 134 can effectively conduct lighting away from the composite component 130.

[0076] The metal fibers 135 may be evenly distributed throughout the conductive portion 134, or may be arranged randomly within the conductive portion 134. An even distribution of metal fibers 134 advantageously allows electrical energy to be conducted evenly through the conductive portion 134.

[0077] The metal fibers 135 may be metal wires that extend from a first end of the conductive portion 134 to a second end of the conductive portion 134.

[0078] As shown in the example in Figure 5, the conductive portion 134 may comprise one or more metal fibers 135 extending in a first direction, depicted by arrow A. In the example shown in Figure 5, the first direction A is parallel to the length of the conductive portion 134, however the first direction may alternatively be in any other direction.

[0079] The conductive portion 134 may be a composite weave (such as a 3D composite weave), and the one or more metal fibers 135 may be woven into the composite weave. This advantageously allows the metal fibers to be easily incorporated into the conductive portion 134, and also improves the mechanical properties of the conductive portion 134 (such as strength).

[0080] The body portion 133 may be a composite weave, such as a 3D composite weave. Metal fibers 134 may be woven into the composite weave to provide the conductive portion 134. The conductive portion 134 may therefore refer to a region of the body portion 133 that has one or more metal fibers 135 woven into it.

[0081] The one or more metal fibers 135 may extend through a depth of the conductive portion 134. In the example where the body portion 133 is a composite weave, such as a 3D composite weave, the one or more metal fibers 135 may be woven through the composite weave in multiple directions. This advantageously provides a conductive portion 134 with improved mechanical properties such as improved strength and impact resistance.The one or more metal fibers 135 may comprise copper fibers. Fibers comprising other metals and alloys may also be used, for example aluminium, steel, gold, silver or brass.

[0082] Some metals may experience corrosion. In particular, some metals experience galvanic corrosion when in contact with carbon fiber. This may affect the performance and integrity of the metal fibers. Therefore, the one or more metal fibers 135 may be coated with a non-corrosive material. The non-corrosive material may comprise polyamide, glass enamel and / or Polytetrafluoroethylene (such as Teflon™).

[0083] Figure 6 shows a schematic view of a conductive portion according to examples of the present disclosure. As shown in the example of Figure 6, the conductive portion 134 may comprise one or more metal fibers 135 extending in a second direction, shown by arrow B, substantially perpendicular to the first direction (shown by arrow A in Figure 5). The metal fibers 135 may be evenly distributed throughout the conductive portion 134 in the first direction and the second direction. This improves the conductivity of the conductive portion 134.

[0084] The conductive portion 134 comprising one or more metal fibers 135 in a first and second direction also allows two separate circuits to be formed: a first circuit comprising the one or more metal fibers in the first direction, and a second circuit comprising the one or more metal fibers in the second direction. This allows the two separate circuits to be individually adapted for improved performance depending on their function.

[0085] The one or more metal fibers 135 extending in the first direction may be longer than the one or more metal fibers 135 extending in the second direction. Longer metal fibers are advantageous for de-icing applications, as longer metal fibers experience more resistance and therefore generate more heat than shorter metal fibers. Shorter metal fibers are advantageous for lightning strike protection, as shorter metal fibers can quickly and effectively conduct and dissipate the electrical energy away from the internal systems of the aircraft and / or components that may be damaged by lightning strike.

[0086] The first circuit may be used as a de-icing system. For example, when current is provided through the one or more metal fibers 135 in the first direction, the one or more metal fibers 135 in the first direction may heat up. This heat may prevent the build-up of ice on the surface of the composite component 130 and / or melt any ice that may be present on the surface of composite component 130.The second circuit may be used as lighting strike protection. For example, when lightning strikes the composite component 130, the one or more metal fibers 135 in the second direction may form part of a conductive path which conducts and dissipates the electrical energy away from damage-prone areas within the engine. For example, the composite component may be connected between the engine core and the upper-side of the frame. Electrical energy from the lightning strike can be conducted away from the engine core through the composite component.

[0087] As the first and second circuit are individually adapted for their specific purpose, the composite component described herein can advantageously provide effective lightning strike protection and effective de-icing capabilities.

[0088] The conductive portion 134 may comprise a switch. When the switch is in a first position, the conductive portion may provide lightning strike protection. When the switch is in a second position, the conductive portion may provide de-icing capabilities. In this way, the conductive portion can be configured depending on the application required.

[0089] The de-icing circuit may be configured in an off-state when not in use. Therefore, current is not supplied to the de-icing circuit unless de-icing is required, and the composite component is energy efficient.

[0090] Figure 7 shows a flow chart of a method for forming a composite component according to examples of the present disclosure. As shown in Figure 7, the method comprises forming the body portion 701, and adding a conductive portion during forming of the body portion, the conductive portion comprising pitch carbon fiber, graphene, or one or more metal fibers 702.

[0091] Forming the body portion 133 and adding a conductive portion 134 may be achieved in a number of ways. The conductive portion may be formed integrally with the body portion. An example method of integrally forming the conductive portion with the body portion is shown in Figure 8.

[0092] Figure 8 shows a schematic view of a process for forming a composite component according to examples of the present disclosure. In the example shown in Figure 8, the composite component 133 is formed of a plurality of layers of composite material. The plurality of layers of composite material may comprise one or more layers of a first material (corresponding to the body portion 133), and one or more layers of a second material (corresponding to theconductive portion 134), wherein the second material has a higher conductivity than the first material.

[0093] As shown in Figure 8, the method may comprise laying one or more layers of the first material (corresponding to the body portion 133), along with one or more layers of the second material (corresponding to the conductive portion 134). This is shown in step A of Figure 8. The method may further comprise inserting the layers of composite material into a preform tool (step B of Figure 8). The preform tool may shape the layers of the first and second material into the basic shape of the composite component.

[0094] The method may further comprise applying heat and pressure (H+P) to the composite material to form a stabilised preform (step C of Figure 8). The stabilised perform may retain its shape in further processing. Applying heat and pressure to the composite material to form a stabilised perform may also improve the mechanical properties of the component, providing enhanced strength and durability, for example.

[0095] The method may further comprise removing the stabilised preform from the preform tool and transferring the stabilised preform into a mould (steps D and E of Figure 8). The shape of the mould may correspond to the final desired shape of the composite component. The method may further comprise injecting resin into the mould (step F of Figure 8).

[0096] The resin may act as a matrix which binds the layers of the first material and the second material together. In this way, the one or more layers of the second material (corresponding to the conductive portion 134) may be integrally formed with the one or more layers of the first material (corresponding to the body portion 133). The resin may bond the one or more layers of the second material (corresponding to the conductive portion 134) and the one or more layers of the first material (corresponding to the body portion 133) together, such that they cannot be separated without damaging the integrity of the composite component.

[0097] The resin may also improve the structural integrity of the component by filling any gaps that may be present in the first and second material, providing improved strength and impact resistance. The resin may also provide a smooth surface finish which is advantageous in aerospace applications.

[0098] The method may further comprise curing the composite component (step G of Figure 8). The curing step may solidify the resin and provide improved mechanical properties such as thermalstability and moisture resistance. The mould is then opened and the composite component is removed from the mould (step H of Figure 8).

[0099] Figure 8 shows one example of a method of forming the composite component in accordance with the present disclosure. Steps A-H are not limited to being performed in the order shown in Figure 8, and one or more of steps A-H may be omitted in accordance with the present disclosure.

[0100] Steps D, E and F may be omitted, and the conductive portion 134 (corresponding to the one or more layers of the second material) may be integrally formed with the body portion 133 (corresponding to the one or more layers of the first material) as a result of the applied heat and pressure in step C of Figure 8. The applied heat and / or pressure may result in the one or more layers of the second material and the one or more layers of the first material being bonded together, such that they cannot be separated without damaging the integrity of the composite component.

[0101] Other example methods of forming the body portion 133 and adding a conductive portion 134 such that the body portion 133 is formed integrally with the conductive portion include weaving the conductive portion into the body portion. For example, the body portion 133 may comprise a composite weave. A composite weave may refer to composite material that is woven from a plurality of individual fibers. A composite weave may also refer to a mesh.

[0102] The conductive portion may comprise one or more metal fibers. The method may comprise weaving the conductive portion into the body portion. The resulting composite component may form a singular woven piece.

[0103] The body portion may comprise a 3D composite weave. The method may comprise weaving the conductive portion into the body portion to form a singular 3D woven piece.

[0104] The body portion may be formed using a conventional method of forming the composite component. An additional step of adding the conductive portion may be introduced into the method at any appropriate time during the forming of the body portion.

[0105] Any of the methods described herein may additionally comprise impregnating the body portion and the conductive portion with resin. This may improve structural integrity, strength and impact resistance, as well as providing a smooth surface to the component. The resin may beepoxy resin or polymer resin. High-temperature polymer resin is particularly advantageous for de-icing systems, as it can its structural integrity at high temperatures.

[0106] Adding the conductive portion according to any of the methods described herein may comprise arranging the conductive portion within the body portion. Where the body portion comprises a plurality of layers of the first material, adding the conductive portion may comprise arranging one or more layers of the second material in between two layers of the first material.

[0107] The body portion may comprise two layers of the first material, and adding the conductive portion may comprise laying a layer of the second material between them. The body portion may comprise a plurality of layers of the first material, and adding the conductive portion may comprise laying one or more layers of the second material between each respective layer of the first material.

[0108] Where the body portion comprises a composite weave, adding the conductive portion may comprise weaving the conductive portion within the body portion. The conductive portion may be woven through a central portion (an area proximate to the centre) of the body portion. The conductive portion may be woven proximate to an outer surface of the composite component.

[0109] Adding the conductive portion according to any of the methods described herein may comprise arranging the conductive portion proximate to an outer surface of the body portion. Where the body portion comprises a plurality of layers of the first material, adding the conductive portion may comprise arranging one or more layers of the second material on top of the one or more layers of the first material proximate to an outer surface of the body portion. Where the body portion comprises a composite weave, adding the conductive portion may comprise weaving the conductive portion into the body portion proximate to an outer surface of the body portion. Arranging the conductive portion proximate to an outer surface of the body portion may comprise doping a portion of the body portion proximate to the outer surface of the body portion with graphene.

[0110] The method may additionally comprise a step of adding one or more glass fibers onto the surface of the composite component. The one or more glass fibers may be a layer of glass fibers that covers all of the surface, or a portion of the surface, of the composite component.

[0111] The methods described herein advantageously provide an improved composite component where the lighting strike protection and / or de-icing system comprise pitch carbon fiber, graphene, or one or more metal fibers. Additional manufacturing steps as well as the hightolerance bolts and complex machining are not required. The difference in properties between the lightning strike protection and the body portion is reduced in comparison to existing lighting strike protection, which reduces fatigue of the resulting component.

Claims

CLAIMS1. A composite component for an aircraft, comprising:a first end;a second end;a body portion having a first conductivity;a conductive portion having a second conductivity, wherein the second conductivity is higher than the first conductivity;wherein the conductive portion comprises pitch carbon fiber, graphene, or one or more metal fibers, and extends from the first end to the second end.

2. The composite component of claim 1, wherein the conductive portion is integrally formed with the body portion.

3. The composite component of any preceding claim, wherein the body portion and the conductive portion are impregnated with resin.

4. The composite component of any preceding claim, wherein the conductive portion extends within the body portion.

5. The composite component of any of any preceding claim, wherein the conductive portion is proximate to an outer surface of the composite component.

6. The composite component of any preceding claim, further comprising one or more glass fibers extending along a surface of the body portion.

7. The composite component of any preceding claim, wherein the composite component comprises a vane.

8. The composite component of claim 7, wherein the conductive portion is proximate to the leading edge and / or trailing edge of the vane.

9. The composite component of any of claims 1 to 6, wherein the composite component comprises a flange.

10. The composite component of any preceding claim, wherein the conductivity is an electrical conductivity and / or a thermal conductivity.

11. The composite component of any preceding claim, wherein the body portion comprises carbon fiber.

12. The composite component of any preceding claim, wherein the body portion comprises PAN carbon fiber.

13. The composite component of any preceding claim, wherein the conductive portion comprises one or more metal fibers extending in a first direction.

14. The composite component of claim 13, wherein the conductive portion comprises one or more metal fibers extending in a second direction substantially perpendicular to the first direction.

15. The composite component of claim 14, wherein the one or more metal fibers extending in the first direction are longer than the one or more metal fibers extending in the second direction.

16. The composite component of any of claims 1-15, wherein the one or more metal fibers comprise copper fibers.

17. The composite component of any of claims 1-16, wherein the one or more metal fibers extend through a depth of the conductive portion.

18. The composite component of any of claims 1-17, wherein the one or more metal fibers are coated with a non-corrosive material.

19. A method of forming the composite component of any preceding claim, comprising:forming the body portion;adding a conductive portion during forming of the body portion, the conductive portion comprising pitch carbon fiber, graphene, or one or more metal fibers.

20. The method of claim 19, wherein the body portion is formed integrally with the conductive portion.

21. The method of any of claims 19-20, further comprising impregnating the body portion and the conductive portion with resin.

22. The method of any of claims 19-21, wherein adding the conductive portion comprises arranging the conductive portion within the body portion.

23. The method of any of claims 19-22, wherein adding the conductive portion comprises arranging the conductive portion proximate to an outer surface of the body portion.

24. An outlet guide vane structure for an aircraft comprising the composite component of any of claims 1-18.

25. An aircraft comprising the composite component of any of claims 1-18.

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