WOVEN FABRICS FOR COMPOSITE COMPONENTS

Abstract

A manufacturing method comprises: providing a woven fabric comprising a plurality of reinforcing fibre tows and a plurality of thermoplastic polymer yarns woven together; and moulding the woven fabric in a heated mould to form a preform for a composite component.

Claims

1. A manufacturing method comprising: providing a woven fabric comprising a plurality of reinforcing fibre tows and a plurality of thermoplastic polymer yarns woven together; and moulding the woven fabric in a heated mould to form a preform for a composite component, 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 fabric comprises no less than 1.0 wt. % and/or no greater than 8.0 wt. % thermoplastic polymer yarn.

2. The manufacturing method of claim 1, wherein the woven fabric is a two-dimensional (2D) woven fabric in which the plurality of reinforcing fibre tows and the plurality of thermoplastic polymer yarns are woven into a 2D structure, and optionally wherein the method comprises: stacking two or more layers of 2D woven fabric on top of one another to form a stack; and moulding the stack in the heated mould to form the preform for the composite component.

3. The manufacturing method of claim 1, wherein the woven fabric is a three-dimensional (3D) woven fabric in which the plurality of reinforcing fibre tows and the plurality of thermoplastic polymer yarns are woven into a 3D structure.

4. The manufacturing method of claim 1, wherein the mould is a 3D shaped mould and the preform is a 3D shaped preform.

5. The manufacturing method of claim 1, comprising heating the woven fabric to a temperature from 50 C. to 250 C. to form the preform, the method optionally further comprising cooling the preform to no greater than 50 C. prior to removal from the mould.

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

7. The manufacturing method of claim 1, wherein the thermoplastic polymer yarns are evenly distributed throughout the woven 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.

8. The manufacturing method of claim 1, wherein providing the woven fabric comprises weaving the plurality of reinforcing fibre tows and the plurality of thermoplastic polymer yarns together, optionally wherein the method comprises weaving the plurality of thermoplastic polymer yarns in a weft direction.

9. The manufacturing method of claim 1, wherein the reinforcing fibre tows are carbon fibre tows.

10. The manufacturing method of claim 1, further comprising introducing matrix material into the preform to form a composite component or part thereof.

11. A preform manufactured by the manufacturing method of claim 1.

12. A composite component manufactured by the manufacturing method of claim 10.

13. A woven fabric for use in the manufacture of a composite component, the woven fabric comprising a plurality of reinforcing fibre tows and a plurality of thermoplastic polymer yarns woven together, wherein, the woven fabric is (a) a 2D woven fabric in which the plurality of reinforcing fibre tows and the plurality of thermoplastic polymer yarns are woven into a 2D structure or (b) a 3D woven fabric in which the plurality of reinforcing fibre tows and the plurality of thermoplastic polymer yarns are woven into a 3D structure; and wherein: (a) each thermoplastic polymer yarn has a linear density no less than 110 dtex and/or no greater than 330 dtex: (b) the woven fabric comprises no less than 1.0 wt. % and/or no greater than 5.5 wt. % thermoplastic polymer yarn; (c) the thermoplastic polymer yarns comprise a polyamide; (d) one or more of the thermoplastic polymer yarns are woven into the fabric in a weft direction; (e) the thermoplastic polymer yarns are evenly distributed throughout the fabric; (f) one or more of the thermoplastic polymer yarns are woven into the fabric parallel to a reinforcing fibre tow; (g) one or more of the thermoplastic polymer yarns are woven into the fabric within a reinforcing fibre tow; (h) one or more of the thermoplastic polymer yarns are twisted into and/or around a reinforcing fibre tow; and/or (i) the reinforcing fibre tows are carbon fibre tows.

14. A method of manufacturing a woven fabric for use in the manufacture of a composite component, the method comprising weaving a plurality of reinforcing fibre tows and a plurality of thermoplastic polymer yarns together, wherein: (a) each thermoplastic polymer yarn has a linear density no less than 110 dtex and/or no greater than 330 dtex; (b) the woven fabric comprises no less than 1.0 wt. % and/or no greater than 5.5 wt. % thermoplastic polymer yarn.

15. The method of claim 14, comprising: (a) weaving the plurality of reinforcing fibre tows and the plurality of thermoplastic polymer yarns together (i) into a 2D structure to thereby form a 2D woven fabric or (ii) into a 3D structure to thereby form a 3D woven fabric; (b) weaving one or more of the thermoplastic yarns into the fabric in a weft direction; (c) distributing the thermoplastic yarns evenly throughout the fabric; (d) weaving one or more of the thermoplastic yarns into the fabric parallel to a reinforcing fibre tow; (e) weaving one or more of the thermoplastic yarns woven into the fabric within a reinforcing fibre tow; and/or (f) twisted weaving one or more of the thermoplastic yarns into and/or around a reinforcing fibre tow.

16. The method of claim 14, wherein: (a) the thermoplastic polymer yarns comprise a polyamide; and/or (b) the reinforcing fibre tows are carbon fibre tows.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0143] Embodiments will now be described by way of example only, with reference to the Figures, in which:

[0144] FIG. 1 is a side view of a composite aircraft panel;

[0145] FIG. 2 illustrates a method of manufacturing a composite aircraft panel;

[0146] FIG. 3 illustrates a unit cell of a 3D woven structure of a 3D woven fabric; and

[0147] FIG. 4 shows two photographs of a 3D woven fabric incorporating thermoplastic polymer yarns woven in the weft direction, the photograph on the left hand side showing the fabric in the as woven state prior to stabilisation and the photograph on the right hand side showing the fabric following stabilisation.

DETAILED DESCRIPTION OF THE DISCLOSURE

[0148] 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.

[0149] FIG. 1 illustrates a composite panel 1 used in the construction of an aircraft. The panel 1 is formed predominantly from a carbon fibre based composite material.

[0150] The carbon fibre based composite material, from which the panel 1 is formed, comprises a woven carbon fibre reinforcement in a polymeric matrix. In the example shown in FIG. 1, the woven carbon fibre reinforcement is a 3D woven carbon fibre reinforcement comprising a plurality of carbon fibre tows woven into a 3D structure. At least some of the carbon fibre tows are bonded to one another in part by thermoplastic polymeric material which is different from the polymeric matrix.

[0151] The panel 1 is manufactured by the method 100 outlined in FIG. 2. In step 101, a 3D woven fabric is manufactured. In step 102, the 3D woven fabric is compressed and stabilised by heating in a mould to form a shaped preform for the panel 1. In step 103, the preform is filled with thermosetting polymeric matrix material in a resin transfer mould, thereby forming the panel 1. In optional step 104, a plurality of said panels 1 are assembled and adhered to one another to form part of an aircraft.

[0152] The 3D woven fabric used in the manufacture of the example panel shown in FIG. 1 comprises a plurality of carbon fibre tows and a plurality of thermoplastic polymer yarns woven together into a 3D structure. When the 3D woven fabric is compressed and stabilised by heating in the mould, the thermoplastic polymer yarns melt and bond adjacent carbon fibre tows together. The preform therefore retains its compressed, stabilised shape on removal from the mould and transfer to the resin transfer mould.

[0153] The 3D woven fabric may have any suitable 3D structure and/or weave pattern. For example, the 3D woven fabric 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, each of which is known to the person skilled in the art.

[0154] In other examples, a composite component may be manufactured using a 2D woven fabric which comprises a plurality of carbon fibre tows and a plurality of thermoplastic polymer yarns woven together into a 2D structure. When the 2D woven fabric is compressed and stabilised by heating in the mould, the thermoplastic polymer yarns melt and bond adjacent carbon fibre tows together. In some examples, a composite component is manufactured by stacking two or more layers of 2D woven fabric on top of one another, wherein some or all of the layers of 2D woven fabric include interwoven thermoplastic polymer yarns. When the layers of 2D woven fabric are compressed and stabilised by heating in the mould, the thermoplastic polymer yarns melt and can bond adjacent carbon fibre tows together and adjacent layers of 2D woven fabric together.

[0155] The 2D woven fabric may have any suitable 2D weave pattern. For example, the 2D woven fabric may have a plain, twill or satin weave pattern.

[0156] The carbon fibre tows of the 2D or the 3D woven fabric 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, or the TORAYCA line available from Toray Composite Materials America, Inc., USA. Alternatively, the carbon fibre may be replaced by other types of reinforcing fibre, such as glass fibre, aramid fibre or basalt fibre.

[0157] The thermoplastic polymer yarns of the 2D or the 3D woven fabric 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.

[0158] The thermoplastic polymer yarns may have a linear density from about 100 dtex to about 350 dtex, for example. The woven 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.

[0159] The thermoplastic polymer yarns may be evenly distributed throughout the 2D or 3D woven fabric. The thermoplastic polymer yarns may be woven into the 2D woven fabric in the warp and/or weft directions or into the 3D woven 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 fabric in at least the weft direction.

[0160] The 2D or 3D woven fabric may be woven using any suitable weaving apparatus, i.e., a loom, such as a Dobby loom or a Jacquard loom. Suitable weaving apparatuses are available from, for example, Lindauer Dornier GmbH, Germany.

[0161] In step 102, the woven fabric is heated to a temperature at which the thermoplastic polymer yarns melt. For example, the woven fabric 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 fabric at the elevated temperature for a long period of time. For example, the woven fabric may be heated up to the desired maximum temperature (e.g., about 100 C.) and then immediately cooled back down towards room temperature. The total heating time may be from about 10 seconds up to about 10 minutes. The woven fabric is typically cooled prior to removal from the mould, so that the thermoplastic polymer solidifies while the compressed woven fabric is held within the mould, thereby locking in the shape of the preform.

[0162] In step 103, the preform 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 or a bismaleimide. The polymeric matrix material may be injected into the preform under pressure within the resin transfer mould. Because the preform has been compressed and stabilised, and because adjacent carbon fibre tows are bonded to one another by thermoplastic 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.

[0163] It will be appreciated that the manufacturing method outlined hereinabove could be used to manufacture any type of composite component and is not limited to the manufacture of a panel for an aircraft.

[0164] In some examples, the shape produced by heating a woven fabric in the mould is essentially the final shape of the composite component being manufactured. For example, the composite component may be manufacture from a single, shaped piece of 3D woven fabric.

[0165] In some examples, the composite component is assembled from a plurality of parts in step 104, one or more which parts are made by shaping 2D or 3D woven fabric as disclosed herein.

[0166] In some examples, two or more preforms may be adhered to one another before injection of polymeric matrix material. For example, since thermoplastic polymeric material remelts on reheating, two or more preforms, which have been manufactured by compressing and stabilising 2D or 3D woven fabric containing thermoplastic polymeric yarns, can be adhered to one another by placing or compressing the preforms together while the preforms are still warm enough that the thermoplastic polymer is molten or at least tacky.

[0167] It will be appreciated that the woven 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. Therefore, the woven fabric may be heated in a 2D shaped mould (e.g., between two flat platens) or in a 3D shaped mould as appropriate.

[0168] It will also be appreciated that the woven fabrics disclosed herein could be impregnated with partially cured polymeric matrix material and/or one or more precursors for (i.e., which can react to form) polymeric matrix material prior to manufacturing a preform or a composite component. Such pre-impregnated (or pre-preg) woven fabrics may be suitable for use in manufacturing preforms and/or composite components by methods other than resin transfer moulding. For example, a preform may be assembled by laying up (e.g., multiple layers of) the pre-impregnated woven fabric and a composite component may be produced by curing the preform, for example, by the application of heat and/or pressure (e.g., in an oven or an autoclave). In such examples, the thermoplastic polymer yarn may provide the final composite component with enhanced toughness.

[0169] FIG. 3 illustrates a unit cell of the 3D woven structure of an example 3D woven fabric incorporating one thermoplastic polymer yarn per weft reinforcing fibre tow. In the structure illustrated in FIG. 3, 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. 3 in the x and y directions.

[0170] FIG. 4 shows photographs of an example 3D woven fabric incorporating thermoplastic polymer yarns woven in the weft direction. In the photograph on the left hand side, the fabric is in the as woven state prior to stabilisation and the thermoplastic polymer yarns are visible as white surface striations as indicated in the Figure. In the photograph on the right hand side, the fabric has been stabilised by the application of heat and pressure, thereby causing the thermoplastic polymer yarns to melt. Individual thermoplastic polymer yarns are no longer visible in the photograph. As described above, when the thermoplastic polymer yarns melt, they bond adjacent carbon fibre tows together. The preform therefore retains its compressed, stabilised shape on removal from the mould and transfer to the resin transfer mould.

[0171] 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.