WOVEN FABRICS FOR COMPOSITE COMPONENTS

Abstract

A manufacturing method includes: in a loom, weaving a woven reinforcing fibre fabric including a plurality of reinforcing fibre tows and polymeric material; and heating the woven reinforcing fibre fabric as it exits the loom to cause the polymeric material to melt and/or cure.

Claims

1. A manufacturing method comprising: in a loom, weaving a woven reinforcing fibre fabric comprising a plurality of reinforcing fibre tows and polymeric material comprising a plurality of thermoplastic yarns, wherein weaving comprises weaving the plurality of reinforcing fibres tows and a plurality of thermoplastic polymer yarns together in the loom to form the woven reinforcing fibre fabric, wherein: (a) each thermoplastic polymer yarn has a linear density no less than 110 dtex and/or no greater than 330 dtex; and/or (b) the woven reinforcing fibre fabric comprises no less than 1.0 wt. % and/or no greater than 8.0 wt. % thermoplastic polymer yarn; and; heating the woven reinforcing fibre fabric as it exits the loom to cause the polymeric material to melt and/or cure.

2. The manufacturing method of claim 1, wherein the method comprises: heating the woven reinforcing fibre fabric under tension as the woven reinforcing fibre fabric exits the loom to cause the polymeric material to melt and/or cure.

3. The manufacturing method of claim 1, wherein each thermoplastic polymer yarn comprises a polyamide.

4. The manufacturing method of claim 1, wherein the thermoplastic polymer yarns are evenly distributed throughout the woven reinforcing fibre fabric and/or one or more of the plurality of thermoplastic polymer yarns is: (a) woven into the fabric parallel to a reinforcing fibre tow; (b) woven into the fabric within a reinforcing fibre tow; or (c) twisted into and/or around a reinforcing fibre tow.

5. The manufacturing method of claim 1, wherein the method comprises: weaving the plurality of reinforcing fibres tows together in the loom; applying polymer-based binder powder to the plurality of reinforcing fibre tows; and heating the woven reinforcing fibre fabric as it exits the loom to cause the polymer-based binder powder to melt and/or cure.

6. The manufacturing method of claim 1, wherein at least some of the reinforcing fibre tows have a polymer-based coating and the method comprises: heating the woven reinforcing fibre fabric as it exits the loom to cause the polymer-based coating to melt and/or cure.

7. The manufacturing method of claim 1, wherein the method comprises: heating the woven reinforcing fibre fabric after carrying out a beat-up operation.

8. The manufacturing method of claim 1, wherein the method comprises: heating the woven reinforcing fibre fabric as it exits the loom using a directed heat source.

9. The manufacturing method of claim 1, wherein the method comprises: heating the woven reinforcing fibre fabric to a temperature from 50 C. to 250 C.

10. The manufacturing method of claim 1, wherein the method comprises: after heating the woven reinforcing fibre fabric, cooling the woven reinforcing fibre fabric under tension to no greater than 50 C.

11. The manufacturing method of claim 1, wherein the woven reinforcing fibre fabric is (a) a 2D woven reinforcing fibre fabric or (b) a 3D woven reinforcing fibre fabric.

12. The manufacturing method of claim 1, wherein the woven reinforcing fibre fabric forms a preform for a composite component and the method further comprises: introducing matrix material into the preform to form the composite component or part thereof.

13. Weaving apparatus comprising: a loom for weaving a woven reinforcing fibre fabric; a heat source configured to heat the woven reinforcing fibre fabric as it exits the loom; and a tensioner for applying tension to the woven reinforcing fibre fabric as it exits the loom, wherein the tensioner comprises a rotatable mandrel configured to receive and draw the woven reinforcing fibre fabric away from the loom.

14. The weaving apparatus of claim 13, wherein the heat source is configured to heat the woven reinforcing fibre fabric downstream of a beat-up point.

15. The weaving apparatus of claim 13, wherein the heat source is a directed heat source.

16. The weaving apparatus of claim 13, wherein the heat source is configured to heat the woven reinforcing fibre fabric to a temperature from 50 C. to 250 C.

17. The weaving apparatus of claim 13, wherein the loom is for weaving (a) a 2D woven reinforcing fibre fabric or (b) a 3D woven reinforcing fibre fabric.

18. A preform manufactured by the method of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0150] Embodiments will now be described by way of example only, with reference to the Figures, in which:

[0151] FIG. 1a shows a side view of weaving apparatus and FIG. 1b a plan view of the weaving apparatus;

[0152] FIG. 2a illustrates a weaving operation and FIG. 2b a beat-up operation;

[0153] FIG. 3 shows a schematic side view of weaving apparatus;

[0154] FIG. 4 illustrates a unit cell of a 3D woven structure of a 3D woven reinforcing fibre fabric;

[0155] FIG. 5 is a flowchart illustrating a manufacturing method; and

[0156] FIG. 6 is a schematic side view of a composite aircraft component.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0157] Aspects and embodiments of the present disclosure will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art.

[0158] FIG. 1a and FIG. 1b illustrates apparatus 100 for manufacturing a composite component. FIG. 1a shows a schematic side view to illustrate a path of reinforcing fibre tows through the apparatus, whereas FIG. 1b schematically shows a plan view of the same apparatus 100.

[0159] The apparatus 100 comprises, in order with respect to the passage of warp tows through the apparatus: a warp tow supply 110, a loom 120, an infrared heat source 130 and a rotatable mandrel 150. The warp tow supply 110 is configured to supply warp tows 112 to the loom 120 for weaving with weft tows at a weave location 122 of the loom. The warp tow supply may comprise a plurality of separate tow supply feeds 114 (e.g. separate tow spools on a creel) each configured to independently supply separate warp tows to the weave location 122 of the loom 120.

[0160] The loom 120 is configured to weave a woven structure 200 using the warp tows 112 supplied from the warp tow supply 110, weft tows (not shown) and binder tows (not shown) supplied at the loom 120. The loom 120 may be of any suitable type as is known in the art. For complex weaves the loom may be programmable (i.e. configured for computer control) to form woven structures 200 with weave patterns based on computer-readable instructions. Such a loom may be referred to as a computer-controlled jacquard loom. The apparatus 100 comprises a loom controller 121 for controlling the loom 120 to weave the woven structure 200, as will be described in further detail below. As shown in FIG. 1a, the loom controller 121 may be coupled to the mandrel to monitor or control a speed of rotation of the mandrel, in order to ensure that the woven structure 200 is woven at an appropriate rate. The loom controller 121 may also be coupled to the infrared heat source 120 to monitor or control an amount of heat supplied to the woven structure exiting the loom.

[0161] In the example shown in FIG. 1a and FIG. 1b the mandrel 150 is for forming a semi-annular or annular component. The woven structure 200, as it exits the loom, may be referred to herein as a woven reinforcing fibre fabric. Additionally or alternatively, the woven structure 200 as received from the loom after heating may be referred to herein as woven preform 200 to reflect that it forms an integral part of the annular component but must be formed to shape and subsequently cured with matrix material (e.g. by a resin transfer moulding (RTM) technique) to form the component. In the example shown in FIG. 1a and FIG. 1b, the mandrel defines a near net shape profile for the composite component. This means that the mandrel defines a profile which is close to the final of the composite component to be manufactured (e.g. except for relatively minor finishing and machining), such that the reader understands that the action of forming the preform woven structure into the shape of the component is conducted by applying the woven fabric (i.e. the preform) to the mandrel 150.

[0162] As the near net shape profile of the mandrel is configured to define a radially inner surface of the base of the composite component, it is implicit that the two sides of the woven preform includes a side to be received on the mandrel (a radially-inner side as received on the mandrel), and an opposing side (a radially-outer side as received on the mandrel). In the following disclosure, the opposing side (the radially-outer as received on the mandrel) is referred to as the first side of the woven preform, and the side to be received on the mandrel (the radially-inner side) is referred to as the second side of the woven preform.

[0163] The woven preform is referred to herein as having a longitudinal direction corresponding to the path along which it is discharged from the loom and drawn to the rotatable mandrel, and a lateral direction orthogonal to the longitudinal direction and extending across the woven preform. The longitudinal direction may correspond to a warp direction of the woven preform (i.e. along which warp tows generally extend), and to a circumferential direction of the rotatable mandrel. The lateral direction may generally correspond to a weft direction of the woven preform, while acknowledging that weft tows may depart from a direction that is precisely orthogonal to the longitudinal and/or warp directions.

[0164] In the example shown in FIG. 1a and FIG. 1b, the woven preform is woven from carbon fibre tows. The carbon fibre tows may comprise any suitable number of carbon fibres. For example, the carbon fibre tows may be 1K, 3K, 6K or 12K carbon fibre tows. For example, the carbon fibre tows may be any suitable commercially available carbon fibre tows. such as those obtained from the HexTow line available from Hexcel Corporation, USA, the TORAYCA line available from Toray Composite Materials America, Inc., USA, or the Tenax line available from Teijin Carbon Europe GmbH, Germany. Alternatively, the carbon fibre may be replaced by other types of reinforcing fibre, such as glass fibre, aramid fibre or basalt fibre.

[0165] The reinforcing fibre tows are coated with a polymer-based coating known as sizing. The sizing can take any form known in the art and an appropriate sizing formulation may be selected based on the properties and/or composition of the reinforcing fibre tows. The sizing may comprise one or more thermoplastic polymers and/or one or more thermosetting polymers or precursors therefor. For example, the sizing may contain: one or more of: polyacrylic acids; acrylonitrile butadiene styrene; polyamides; polylactic acids; polycarbonates; polyether sulfones; polyoxymethylene; polyether ether ketones; polyetherimides; polyolefins (i.e. polyalkenes) such as polyethylene and/or polypropylene; polystyrene; polyvinyl chloride; polyvinylidene fluoride; and/or polytetrafluoroethylene; and/or one or more of: polyesters (e.g. polyester resins, for example, isophthalic polyester resins and/or unsaturated polyester resins); UV-curable monomers; vinyl esters (e.g. vinyl ester resins, for example, bisphenol A vinyl esters such as VR-60); acrylic resins (e.g. acrylic resins with epoxy and unsaturated groups, such as PD-3402); polyamides; epoxy resins (e.g. catalysed epoxy resins and/or non-catalysed epoxy resins, for example, bismaleimide triazine epoxy (BT-epoxy) resin); acrylonitriles; phthalonitrile resins; vinyl chlorides; and/or acrylonitrile-vinyl chloride copolymers. The sizing may also contain, for example, water, coupling agents (e.g. silanes), surfactants, plasticizers, anti-static agents, anti-foaming agents ; rheology modifiers, and/or other additives or modifiers.

[0166] In use, the infrared heat source 130 is operated to heat the woven structure 200 as it exits the weave location 122 of the loom 120. On heating, the sizing coating the reinforcing fibre tows melts (for example, if the sizing contains one or more thermoplastic polymers) and/or begins curing (for example, if the sizing contains one or more thermosetting polymers or precursors therefor), which causes adjacent reinforcing fibre tows in the woven structure 200 to begin to adhere to one another at tow crossover locations. At the same time, tension applied to the woven structure 200 by rotating the mandrel 150 about its axis A pulls the warp tows taught. As the woven structure 200 moves away from the infrared heat source 130 and onto the mandrel 150, the woven structure 200 cools and the sizing resolidifies (for example, if the sizing contains one or more thermoplastic polymers) and/or finishes curing (for example, if the sizing contains one or more thermosetting polymers or precursors therefor), which the causes adjacent reinforcing fibre tows in the woven structure 200 to bond to one another at tow crossover locations, thereby fixing the woven structure 200 in place. Because the woven structure 200 is subjected to tension during the heating and cooling process, the reinforcing fibre tows are bonded to one another in a compact structure. The woven preform 200 formed on the mandrel 150 is therefore compacted and stabilised and contains significantly less trapped air than woven preforms prepared using alternative methods.

[0167] The loom 120 shown in the example of FIG. 1a and FIG. 1b weaves a 3D woven structure 200. The 3D woven structure may have any suitable 3D structure and/or weave pattern. For example, the 3D woven structure may have a through-thickness interlock structure or a layer-to-layer structure, an angle interlock structure or an orthogonal interlock structure, and/or a plain, twill or satin weave pattern.

[0168] In other examples, however, the loom 120 may be configured to weave a 2D woven structure. The 2D woven structure may have any suitable 2D weave pattern. For example, the 2D woven structure may have a plain, twill or satin weave pattern.

[0169] The loom 120 may be any suitable type of a loom known in the art, such as a Dobby loom or a Jacquard loom. Suitable looms are available from, for example, Lindauer Dornier GmbH, Germany.

[0170] It will be appreciated that the mandrel 150 may be replaced by any suitable tensioner for applying longitudinal tension to the woven structure 200. For example, tension may be applied by pulling the woven structure 200 axially (i.e. in the longitudinal direction) or by winding the woven structure 200 onto a tool (e.g. such as the mandrel 150). For example, an edge of the woven structure 200 may be clamped onto a puller bar and the bar pulled away from the loom 120 by a cable. The type and arrangement of tensioner used will depend on whether a flat preform panel or a 3D shaped preform is to be produced.

[0171] The infrared heat source 130 is configured to heat the woven structure 200 to a temperature at which the sizing melts and/or cures (as appropriate). For example, the woven structure may be heated to a temperature from about 50 C. to about 250 C., such as about 100 C. It may not be necessary to hold the woven structure at the elevated temperature for a long period of time. For example, the woven reinforcing fibre fabric may be heated up to the desired maximum temperature and then immediately cooled back down towards room temperature. For example, the total heating time may be from about 1 second up to about 1 minute.

[0172] In the example shown in FIG. 1a and FIG. 1b, the infrared heat source 130 is an infrared heating lamp. However, it will be appreciated that the infrared heat source 130 can be replaced by any suitable heat source known in the art, such as any suitable type of heat lamp or resistive heating element. The heat source may be a directed heat source which can be directed towards the woven structure 200 at a particular location. The apparatus 100 may also include a temperature sensor (not shown) for measuring a temperature of the woven structure 200 or a temperature close to the woven structure 200. The loom controller 121 may take into account an output from the temperature sensor when controlling operation of the heat source 130.

[0173] As shown in FIG. 1a and FIG. 1b, the heat source 130 is located immediately downstream of the loom 120. However, the heat source 130 may be located anywhere between the weave location 122 and the mandrel 150.

[0174] A simplified loom weaving process is illustrated in more detail in FIGS. 2 (a) and (b). As illustrated in FIG. 2a, a 2D woven structure 300 is formed by weaving together warp tows 310, 320 and a weft tow 330. Warp tows 310 and 320 are separated from one another to form a space known as the shed 340. A weft tow 330 is passed from one edge of the fabric to the other edge using a shuttle, a projectile, a rapier, or the like. The inserted weft tow 330 is known as a pick. As illustrated in FIG. 2b, a tool known as a batten or beater 350 is pushed in the direction indicated by arrow 360 to push a newly created pick into the woven structure 330, at a point known as the fell of the fabric. This operation is known as beat-up. The position of the warp tows 310 and 320 is then adjusted according to the weave pattern to be created and the process is repeated to form another pick.

[0175] The heat source 130 may therefore be configured (i.e. positioned and arranged) to heat the woven structure 200, 300 after the beat-up operation has been carried out (i.e. after the fell point). This is illustrated in FIG. 3 which shows in schematic side view the location of 130 heat source 130 immediately downstream of the fell point.

[0176] In the example illustrated in FIG. 1a and FIG. 1b and described hereinabove, adjacent reinforcing fibre tows are bonded to one another by melting and/or curing sizing which coats the reinforcing fibre tows. However, bonding may be achieved by introducing polymeric material into the woven structure in different ways.

[0177] For example, a polymer-based binder powder may be applied to the reinforcing fibre tows prior to heating the woven structure 200. The binder powder may be applied to the reinforcing fibre tows prior to weaving, during the weaving process (for example, at the fell point) or after the woven structure has been formed (for example, as the woven structure exits the loom). The binder powder may take any form known in the art and may comprise one or more thermoplastic polymers and/or one or more thermosetting polymers or precursors therefor. For example, the binder powder may contain: one or more of: polyacrylic acids; acrylonitrile butadiene styrene; polyamides; polylactic acids; polycarbonates; polyether sulfones; polyoxymethylene; polyether ether ketones; polyetherimides; polyolefins (i.e. polyalkenes) such as polyethylene and/or polypropylene; polystyrene; polyvinyl chloride; polyvinylidene fluoride; and/or polytetrafluoroethylene; and/or one or more of: polyesters (e.g. polyester resins, for example, isophthalic polyester resins and/or unsaturated polyester resins); UV-curable monomers; vinyl esters (e.g. vinyl ester resins, for example, bisphenol A vinyl esters such as VR-60); acrylic resins (e.g. acrylic resins with epoxy and unsaturated groups, such as PD-3402); polyamides; epoxy resins (e.g. catalysed epoxy resins and/or non-catalysed epoxy resins, for example, bismaleimide triazine epoxy (BT-epoxy) resin); acrylonitriles; phthalonitrile resins; vinyl chlorides; and/or acrylonitrile-vinyl chloride copolymers. In some examples, the binder powder is an uncured resin powder.

[0178] Additionally or alternatively, polymeric material may be woven directly into the woven structure 200. For example, the loom may be configured to weave the reinforcing fibre tows together with one or more thermoplastic polymer yarns.

[0179] The thermoplastic polymer yarns may be made of any suitable thermoplastic polymers. For example, the thermoplastic polymer yarns may be made of one or more of: polyacrylic acids; acrylonitrile butadiene styrene; polyamides; polylactic acids; polycarbonates; polyether sulfones; polyoxymethylene; polyether ether ketones; polyetherimides; polyolefins (i.e. polyalkenes) such as polyethylene and/or polypropylene; polystyrene; polyvinyl chloride; polyvinylidene fluoride; and/or polytetrafluoroethylene. More particularly, the thermoplastic polymer yarns may be made of a polyamide such as nylon 6 or nylon 6,6 (i.e. PA 6 or PA 66) or a polyphthalamide such as PA 6T. For example, the thermoplastic polymer yarns may be made of a polyamide available in the Grilon line produced by EMS-GRIVORY, a division of EMS-CHEMIE AG, Switzerland. A suitable polyamide yarn from the Grilon line is KE-60.

[0180] The thermoplastic polymer yarns may have a linear density from about 100 dtex to about 350 dtex, for example. The woven reinforcing fibre fabric may include from about 1.0 wt. % to about 8.0 wt. %, for example, from about 1.0 wt. % to about 5.5 wt. %, of the thermoplastic polymer yarn.

[0181] The thermoplastic polymer yarns may be evenly distributed throughout the woven reinforcing fibre fabric. The thermoplastic polymer yarns may be woven into a 2D woven reinforcing fibre fabric in the warp and/or weft directions or into the 3D woven reinforcing fibre fabric in any of the warp, weft and/or binder directions. In some examples, the thermoplastic polymer yarns are woven into the 2D or 3D woven reinforcing fibre fabric in at least the weft direction.

[0182] FIG. 4 illustrates a unit cell of the 3D woven structure of an example 3D woven reinforcing fibre fabric incorporating one thermoplastic polymer yarn per weft reinforcing fibre tow. In the structure illustrated in FIG. 4. each thermoplastic polymer yarn sits on the surface of a corresponding weft fibre tow. The full 3D woven structure of the fabric can be reproduced by repeating the unit cell shown in FIG. 4 in the x and y directions.

[0183] Any of the different ways of introducing polymeric material into the woven structure (i.e. through use of a polymer-based sizing, a polymer-based binder powder and/or thermoplastic polymer yarns) may be combined with each other or used independently of each other.

[0184] The preform 200 may be manufactured by the method 400 outlined in FIG. 5. At 401, a fabric is woven from reinforcing fibre tows. At 402, polymeric material is incorporated into the fabric. At 403, the fabric is heated to cause the polymeric material to melt and/or begin curing while the fabric is held under tension. At 404, the fabric is cooled such that the polymeric material solidifies and/or finishes curing. It will be appreciated that steps 401 and 402 may take place sequentially or concurrently, dependent on how polymeric material is incorporated into the fabric. For example, incorporating polymeric material into the fabric may comprise weaving thermoplastic polymer yarns into the fabric, weaving the fabric from reinforcing fibre tows which are coated with a polymer-based sizing, or applying binder powder to the reinforcing fibre tows before or during weaving, in which cases steps 401 and 402 take place concurrently.

[0185] In subsequent steps, the preform 200 may be filled with any suitable polymeric matrix material. The polymeric matrix material is typically a thermosetting polymeric matrix material, such as an epoxy resin, a phenolic resin, an amino resin, a cyanate ester resin, a polyurethane, a polyimide, a polyamide, a bismaleimide, or a phthalonitrile resin. The polymeric matrix material may be injected into the preform under pressure within the resin transfer mould. Because the preform has already been compacted and stabilised, and because adjacent reinforcing fibre tows are bonded to one another by polymer, there is typically a low volume fraction of voids and/or air within the preform and injection of the polymeric matrix material is therefore easier and more complete than in conventional manufacturing methods. Any suitable type of resin transfer moulding (e.g. vacuum assisted resin transfer moulding) may be used dependent on the component to be manufactured and the materials used.

[0186] FIG. 6 illustrates a composite component 500 manufactured using a method as described hereinabove. In the example shown in FIG. 6, the component 500 is a panel for an aircraft. However, it will be appreciated that the manufacturing method outlined hereinabove could be used to manufacture any type of preform or composite component.

[0187] In some examples, the shape produced by heating and cooling the woven reinforcing fibre fabric (e.g. on a tool) is essentially the final shape of the composite component being manufactured. For example, the composite component may be manufactured from a single, shaped piece of 3D woven reinforcing fibre fabric.

[0188] In some examples, the composite component is assembled from a plurality of parts, one or more which parts are made by shaping woven reinforcing fibre fabric as disclosed herein.

[0189] In some examples, two or more preforms may be adhered to one another before injection of polymeric matrix material. In examples in which the preforms have been manufactured using thermoplastic polymeric material (e.g. thermoplastic polymer yarns), since thermoplastic polymeric material remelts on reheating and/or can remain tacky following initial heating, two or more preforms can be adhered to one another using the thermoplastic polymeric material.

[0190] It will be appreciated that the woven reinforcing fibre fabrics disclosed herein can be used to manufacture 2D shaped preforms for composite components, 2D shaped composite components or parts thereof, 3D shaped preforms for composite components and/or 3D shaped composite components or parts thereof.

[0191] It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.