A method of making a wind turbine blade shear web

Abstract

In a first aspect of the present invention there is provided a method of making a wind turbine blade shear web comprising an elongate web panel and an elongate web foot. The method comprises providing an elongate web panel component. The method further comprises providing a strip of material comprising a plurality of plies comprising reinforcing fibres, the plurality of plies being arranged in a stack. The method comprises roll forming the strip of material into an elongate roll-formed web foot component having the plurality of plies arranged in a layered structure and comprising a base and an upstand extending substantially transverse to the base. Roll forming the strip of material comprises applying heat to the strip of material. Roll forming the strip of material also comprises feeding the strip of material through at least one roller which bends a first portion of the strip relative to a second portion of the strip such that the first portion extends substantially transverse to the second portion. The first portion thereby defines at least part of the upstand of the roll-formed web foot component and the second portion thereby defines at least part of the base of the roll-formed web foot component. The method further comprises attaching the upstand of the elongate roll-formed web foot component to the elongate web panel component.

Description

[0001] A method of making a wind turbine blade shear web

[0002] Technical field

[0003] The present invention relates generally to wind turbine blades and more particularly to a method of making a wind turbine blade shear web.

[0004] Background

[0005] Wind turbine blades for megawatt wind turbines typically feature a substantially hollow outer shell supported by a longitudinally extending spar structure. A spar structure may include spar caps associated with each of a windward and leeward side of the blade, and a shear web attached between the spar caps. The shear web extends longitudinally within the blade to absorb and transfer shear loads experienced by the blade in use. The shear web may include a longitudinally-extending web foot via which the shear web is attached to the spar caps and / or outer shell. A web foot may stabilise the shear web during assembly, and may provide an increased surface area for distributing the loads transferred to and from the shear web in use.

[0006] Existing shear web manufacturing methods include bonding a pultruded web foot to a web panel, or forming the web foot integrally with the web panel in a resin transfer moulding process. However, each of these methods requires specific manufacturing apparatus to form any particular web foot design. For example, a pultrusion process requires specifically shaped dies for each web foot design, and an integrated web moulding process requires a specifically shaped shear web mould. A blade manufacturing facility may therefore require multiple sets of manufacturing equipment to form different web foot designs for different blades. This can be expensive and also takes up floor space in the blade manufacturing facility.

[0007] It is against this background that the present invention has been developed. Summary

[0008] In a first aspect of the present invention there is provided a method of making a wind turbine blade shear web comprising an elongate web panel and an elongate web foot. The method comprises providing an elongate web panel component. The method further comprises providing a strip of material comprising a plurality of plies comprising reinforcing fibres, the plurality of plies being arranged in a stack. The method comprises roll forming the strip of material into an elongate roll-formed web foot component having the plurality of plies arranged in a layered structure and comprising a base and an upstand extending substantially transverse to the base. Roll forming the strip of material comprises applying heat to the strip of material. Roll forming the strip of material also comprises feeding the strip of material through at least one roller which bends a first portion of the strip relative to a second portion of the strip such that the first portion extends substantially transverse to the second portion. The first portion thereby defines at least part of the upstand of the roll-formed web foot component and the second portion thereby defines at least part of the base of the roll-formed web foot component. The method further comprises attaching the upstand of the elongate roll-formed web foot component to the elongate web panel component.

[0009] In some examples, the elongate web foot may be configured for attaching the shear web to an interior surface of a wind turbine blade shell. In some examples, the elongate web foot may be configured for attaching the shear web to a spar component, such as a spar cap, of a wind turbine blade. A web foot may provide an increased surface area for stabilising the shear web during assembly with a blade shell and may facilitate simplified attachment of the shear web to the blade shell or other spar components. The elongate roll-formed web foot component may form at least part of the web foot. In some examples, the elongate roll-formed web foot component may form substantially all of the web foot.

[0010] The method of making a wind turbine blade shear web, including roll forming the web foot component, may be used to make a plurality of different shear web designs using the same roll forming apparatus. For example, the at least one roller may be reconfigured to roll form different web foot components for different shear webs for different wind turbine blades. The method may therefore offer flexibility for a shear web, or wind turbine blade, manufacturing facility to make multiple different shear web designs without requiring unique tooling such as moulds or dies. Shear webs and associated manufacturing apparatus such as moulds may be very large, such as more than 50 m in length, and the method may be advantageous for saving space in a manufacturing facility whilst still facilitating manufacture of a plurality of different shear web designs for a plurality of different blades.

[0011] Feeding the strip of material through the at least one roller may comprise one or more of pushing, pulling (i.e. drawing), conveying (e.g. on a belt press), or guiding the strip of material through the at least one roller. Pulling (i.e. drawing) the strip of material through the at least one roller may be advantageous to help ensure that the strip of material remains taut, thereby minimising the risk of wrinkles or kinks forming in the strip of material and in the layered structure of the resultant elongate roll-formed web foot component.

[0012] The method may comprise applying heat to the strip of material before feeding the strip of material through the at least one roller. The method may comprise feeding a heated strip of material through the at least one roller. This may improve flexibility of the plurality of plies comprising reinforcing fibres. Additionally or alternatively, in some examples the method may comprise applying heat to the strip of material after the strip of material is roll formed by the at least one roller. For example, the method may comprise applying heat to the strip of material after roll forming to activate and / or cure a binder to secure the plurality of plies together and thereby form the elongate roll-formed web foot component.

[0013] In some examples, the at least one roller may comprise a pair of rollers. The pair of rollers may comprise mutually opposed rollers between which is fed the strip of material.

[0014] In some examples the at least one roller may comprise a series of rollers.

[0015] In some examples, the series of rollers may comprise a plurality of consecutive pairs of rollers. It should be understood that the term consecutive refers to the order in which the strip of material encounters, and is roll formed by, each roller when the strip is fed through the series of rollers. Each pair of rollers may be configured to incrementally bend the first portion of the strip relative to the second portion of the strip.

[0016] Following the roll forming process, the first portion of the strip may be described as being inclined relative to the second portion of the strip. For example, an inclination angle may be defined between the first portion of the strip and the second portion of the strip. The inclination angle may also be defined between the base and the upstand of the roll-formed web foot component.

[0017] The at least one roller, or in some examples pairs of rollers, are configured to adjust the inclination of the first portion of the strip relative to the second portion. Consecutive rollers, or consecutive pairs of rollers in a series of rollers, may be configured to roll form the strip by incrementally adjusting the inclination angle between the first and second portions of the strip as it passes through the series of rollers.

[0018] Following the roll forming process, the inclination angle defined between the base and the upstand of the roll-formed web foot component, i.e. between the first portion and the second portion of the strip, may be less than 180 degrees, preferably less than 150 degrees. In a preferred example, the inclination angle is between 30 degrees and 150 degrees. The elongate roll-formed web foot component may have an L-shaped profile.

[0019] The elongate web panel component may be a substantially planar component. The elongate web panel component may comprise core material, such as a polymer foam or other lightweight material such as balsa wood. In some examples the core material may comprise a honeycomb structure. In some examples, the elongate web panel may have a composite sandwich structure. For example, the web panel component, such as core material, may be sandwiched between fibre reinforced laminate skins.

[0020] The plurality of plies in the strip of material may comprise reinforcing fibres such as glass fibres, carbon fibres, or aramid fibres. The plies may be in the form of a fabric, such as a woven or non-woven fabric. Alternatively, the plies may be in the form of a chopped strand mat.

[0021] The plurality of plies comprising reinforcing fibres in the strip of material may comprise biaxial fibre material in which each reinforcing fibre is aligned in one of two directions. For example, the biaxial fibre material may comprise reinforcing fibres oriented at + / - 45 degrees to a longitudinal direction of the strip of material. It should be understood that the strip of material may be fed through the at least one roller in a direction substantially parallel to the longitudinal direction of the strip. In some preferred examples, the plies comprising reinforcing fibres may comprise less than 5%, preferably less than 2%, or more preferably no reinforcing fibres oriented in the longitudinal direction of the strip of material. This may improve the flexibility of the plies for the roll forming process.

[0022] The web panel component is elongate and the roll-formed web foot component is elongate. In other words, the largest dimension of the web panel component is its longitudinal dimension. Similarly the largest dimension of the roll-formed web foot component is its longitudinal dimension. The web panel component extends longitudinally in a longitudinal direction of the web panel component. The roll-formed web foot component extends longitudinally in a longitudinal direction of the web foot component. In some preferred examples, the method may comprise attaching the upstand of the elongate roll-formed web foot component to the web panel component such that the longitudinal direction of the web foot component is substantially parallel to the longitudinal direction of the web panel component. In other words, the web foot component and web panel component may extend longitudinally in substantially the same direction.

[0023] In some preferred examples, the method may comprise directly attaching the upstand of the elongate roll-formed web foot component to the elongate web panel. By way of nonlimiting example, and as described later in more detail, the upstand of the elongate roll-formed web foot component may be adhesively bonded, co-bonded, or welded to the web panel, in some examples. Direct attachment of the elongate roll-formed web foot component to the web panel may simplify the assembly process and may be advantageous for load transfer between the web panel and web foot in use.

[0024] It should be understood that the plurality of plies comprising reinforcing fibres are preferably all roll formed simultaneously to form the base and the upstand of the elongate roll-formed web foot component. For example, the web foot component is preferably formed in a single roll-forming process in which the strip of material, which comprises the plurality of plies arranged in a stack, is roll formed by the at least one roller.

[0025] In some examples, providing the strip of material may comprise assembling the strip of material. The strip of material may be assembled by arranging a plurality of separate plies comprising reinforcing fibres in a stacked arrangement before the assembled strip is fed through the at least one roller. For example, the strip of material may be described as being formed upstream of the at least one roller. In some examples, the strip of material may be assembled offline, before being fed through the at least one roller. In some other examples, the strip of material may be assembled immediately before the strip is fed through the at least one roller. The method of making the wind turbine blade shear web may comprise assembling the strip of material and roll forming the strip of material in the same manufacturing facility and / or using the same manufacturing apparatus.

[0026] In some examples, the plurality of plies may be unwound from respective spools before being arranged together in a stacked arrangement to form the strip. This facilitates increased flexibility in the build-up of the elongate roll-formed web foot component. For example, the number of plies assembled together to form the strip can be varied along the length of the strip. In other words, such a configuration facilitates ply drop off whereby the number of plies forming the strip of material can be varied along the length of the strip. Forming the strip offline and / or upstream of the at least one roller may also facilitate variation in the type of plies, i.e. the material of the plies, included along the length of the strip. The laminate structure of the resulting elongate roll-formed web foot component may vary, in terms of the number of plies present and / or the type of plies present, along the length of the elongate roll-formed web foot component.

[0027] The plurality of plies may have different widths, so that edges of the base and the upstand may be tapered in thickness. This is beneficial for load distribution into or out of the web foot.

[0028] In some examples, the plies may comprise dry fibrous material and an uncured binder which may be provided between adjacent plies in the stack. The binder may be a polymer-based binder. The binder may be a thermosetting polymer binder. For example, the binder may be an epoxy-based binder, such as an epoxy resin. In some other examples, the binder may be a thermoplastic binder. In an example, the binder may be in the form of a powder, or sprayed on, or embedded around the fibres.

[0029] The binder may be a dry binder, such as a layer or sheet of binder material, or a binder in powder form. Alternatively, the binder may be a liquid binder. In some examples, the binder may be arranged between the adjacent plies when arranging the plurality of plies into the stack, immediately before the strip is fed through the at least one roller. When using a dry binder, it may be arranged between adjacent plies in the stack when assembling the strip of material offline and / or upstream of the at least one roller.

[0030] In some examples, applying heat to the strip of material may activate the binder, thereby liquefying the binder and / or reducing the viscosity of the binder. This may help to promote sliding of the plies relative to one another when fed through the at least one roller.

[0031] In some examples, the method may further comprise at least partially curing the binder after the strip of material is fed through the at least one roller to secure the plies comprising reinforcing fibres together to form a pre-formed elongate roll-formed web foot component. The pre-formed, elongate, roll-formed web foot component may be described as a preform, i.e. a web foot component that is pre-formed before being attached to the elongate web panel component. The pre-formed web foot component may be mostly uncured but geometrically stable for further processing, such as attachment to the shear web panel component. The plurality of plies may be secured together in the roll-formed configuration such that the roll-formed geometry of the web foot component is maintained following the roll forming process. In some examples, heat may be applied to the strip of material after passing through the at least one roller to thereby at least partially cure the binder. In some examples the binder may be at least partially cured under ambient conditions, over time. In some examples, the step of applying heat to the strip of material may only be performed during and / or after the roll forming process, and the method may not necessarily involve applying heat to the strip before the roll-forming process.

[0032] In some examples, the plurality of plies may comprise a fibre-reinforced thermoplastic material. In such examples, the method may comprise applying heat to the strip of material before feeding the strip of material through the at least one roller. This may improve flexibility of the plurality of plies of fibre-reinforced thermoplastic material. The plies of fibre-reinforced thermoplastic material may comprise a thermoplastic sheet with attached fibres, such as an Organosheets. In some other examples, one or more of the plies may comprise thermosetting material.

[0033] The plurality of plies may be plies of pre-preg fibrous material, in some examples. For example, a ply of pre-preg fibrous material may comprise reinforcing fibres preimpregnated with resin. The or each ply of pre-preg fibrous material may be preimpregnated with resin prior to the roll forming process. The step of applying heat to the strip of material may reduce the viscosity of the resin in the pre-preg fibrous material plies and / or reduce tackiness to promote sliding of the plies relative to one another when the strip is fed through the at least one roller.

[0034] In some examples, the method may further comprise a thermoplastic welding process after feeding the strip of material through the at least one roller. Such a thermoplastic welding process may comprise fusing the plurality of plies of fibre-reinforced thermoplastic material together.

[0035] The roll forming process and the thermoplastic welding process may form a pre-fabricated web foot component. The pre-fabricated web foot component may be cured, i.e. the plies of fibre-reinforced thermoplastic material may be fused together. The resultant prefabricated elongate roll-formed web foot component may be a one-piece laminate component. The pre-fabricated web foot component may be a substantially finished component which is geometrically stable and ready for further processing, such as attachment to the shear web panel component.

[0036] The thermoplastic welding process may comprise applying heat and / or pressure to the plies of fibre-reinforced thermoplastic material. The method may comprise feeding the roll- formed plies of fibre-reinforced thermoplastic material through one or more pairs of compaction rollers which apply pressure to the fibre-reinforced thermoplastic material to assist the fusion of the plies.

[0037] In some examples, attaching the upstand of the elongate roll-formed web foot component to the elongate web panel component may comprise at least one of thermoplastic welding, adhesive bonding, or co-bonding the upstand to the elongate web panel component. As described previously with reference to the web foot component, thermoplastic welding may comprise the application of heat and / or pressure to fuse together two or more thermoplastic components.

[0038] Co-bonding is defined herein as the bonding together of a pre-fabricated component and an uncured element at the same time as the uncured element is cured. A pre-fabricated component, such as a pre-fabricated web foot component, should be understood to refer to a substantially finished component which is cured. An uncured element may include a composite layup of the shear web panel. An uncured composite layup of the shear web panel may comprise the elongate web panel component. A pre-fabricated web foot component may be pre-fabricated before being co-bonded with the elongate web panel component at the same time as the composite layup of the shear web panel is cured to form the shear web.

[0039] Co-bonding the upstand of the elongate roll-formed web foot component to the elongate web panel component may comprise arranging the web foot component in a shear web mould with an uncured composite layup comprising the web panel component which is arranged to form the shear web panel. A bonding medium may be provided at an interface between the pre-fabricated web foot component and the elongate web panel component. For example, the bonding medium may be the same resin introduced to the composite layup to integrate the layup and form a composite shear web panel. The pre-fabricated web foot component and the web panel component may be co-bonded by simultaneously bonding the pre-fabricated web foot component to the web panel component in the composite layup and curing the resin introduced to the uncured composite layup to form the shear web panel.

[0040] Whilst examples of co-bonding have been described with reference to a pre-manufactured web foot component comprising a plurality of plies of fibre-reinforced thermoplastic material, it should be understood that a co-bonding process may be equally applicable in examples where the elongate roll-formed web foot component does not necessarily comprise fibre-reinforced thermoplastic material. For example, co-bonding may be a suitable method of attaching any pre-fabricated roll-formed web foot component to the web panel.

[0041] The method may further comprise supplying a resin to saturate the plies comprising reinforcing fibres. In some examples the resin may be supplied in the form of pre-preg plies as discussed above, or in some other examples the resin may be supplied to a pre-formed dry fibre web foot component in an impregnation and / or infusion process. In each example the method may further comprise curing the resin such that the reinforcing fibres are fixed in a resin matrix, thereby forming a pre-fabricated elongate roll-formed web foot component. Such a pre-fabricated roll-formed web foot component may be adhesively bonded, or co-bonded to the web panel as described previously.

[0042] In some examples, the method may further comprise arranging the pre-formed elongate roll-formed web foot component in a shear web mould. The method may comprise arranging a composite layup comprising the elongate web panel component in the shear web mould. The method may comprise co-infusing the pre-formed elongate roll-formed web foot component and the composite layup with a resin, and curing the resin.

[0043] In some examples, co-infusing the pre-formed elongate roll-formed web foot component and the shear web panel layup with a resin may comprise a resin infusion process such as vacuum assisted resin transfer moulding (VARTM). Co-infusing the web foot component with the shear web panel layup may form the shear web foot integrally with the web panel. This may help to minimise the risk of defects or discontinuities in a joint between the web foot and the web panel.

[0044] Existing layup methods for integrally forming a web foot with the web panel may require complex mould components and clamping arrangements to temporarily hold fibre plies in place before an infusion process, and may introduce a risk of forming wrinkles or kinks in the layup if the plies move relative to one another. Conversely, in the examples of a preformed web foot component described herein, the plies comprising reinforcing fibres may be secured together in the roll-formed configuration. Securing the plies together minimises the risk of wrinkles or kinks forming in the plies. A pre-formed web foot component may also be self-supporting and have a stable geometry, such that no complex mould components and clamping arrangements are required for supporting the plies.

[0045] In some examples, roll forming apparatus including the at least one roller may be arranged in line with a shear web mould. The method may comprise extracting the elongate roll- formed web foot component from the roll forming apparatus and depositing the web foot component directly into the shear web mould. Such an arrangement may help to minimise handling of the elongate roll-formed web foot component. Such an arrangement may increase the manufacturing efficiency and throughput of a shear web or wind turbine blade manufacturing facility.

[0046] In some preferred examples, the roll forming apparatus may be arranged with the shear web mould such that the longitudinal direction of the resultant roll-formed web foot component is substantially parallel to a longitudinal direction of the shear web mould. The method may comprise extracting the elongate roll-formed web foot component from the roll forming apparatus and feeding the web foot component into the shear web mould without substantially reorienting the web foot component. Such an arrangement may increase the manufacturing efficiency and throughput of a shear web or wind turbine blade manufacturing facility.

[0047] In some examples, the method may comprise providing a shear web mould comprising a longitudinally-extending main surface shaped to form at least part of the elongate web panel. The method may comprise arranging one or more layers of fibrous material on the main surface. The method may also comprise arranging the elongate web panel component on the main surface. The method may further comprise arranging the upstand of the elongate roll-formed web foot component on the main surface on top of and / or under at least one layer of fibrous material. Further, the method may comprise providing uncured resin to the fibrous material on the main surface and between the upstand, the at least one layer of fibrous material, and the web panel component. The method may comprise curing the uncured resin to thereby attach the upstand of the elongate roll-formed web foot component to the elongate web panel component. Curing the uncured resin may attach the upstand to the web panel component in a co-infusion or co-bonding process in accordance with the examples described previously.

[0048] Wind turbine blades, in particular the outer shells of wind turbine blades typically twist along their length to maximise lift generated when wind is incident on the blade in use. In examples where a blade is twisted, an angle defined between the shear web panel and the surface to which the shear web is attached, such as a spar cap and / or the blade shell, may vary along the length of the shear web.

[0049] An inclination angle defined between the base and the upstand of the roll-formed web foot component may vary along the length of the web foot component. A web foot component comprising a varying inclination angle is particularly beneficial as the web foot can account for twist in the blade such that the base of the web foot can be aligned with the surface of the shell and / or spar cap to which it is attached. This reduces adhesive usage between the base of the web foot and the surface to which it is attached.

[0050] In some examples the at least one roller may comprise at least one pair of actuated rollers. The method may comprise actuating the at least one pair of actuated rollers between a first position and a second position whilst feeding the strip of material through the at least one roller, which may be a series of rollers. In such an example of the method, the resultant roll-formed web foot component may comprise an inclination angle that varies along the length of the web foot component. As described previously, the inclination angle may be defined between the first and second portions of the strip of material, and similarly between the upstand and the base of the resultant roll-formed web foot component. The inclination angle between the first and second portions of the strip may be varied during the roll forming process by actuating the or each pair of actuated rollers. The upstand and / or base of the resultant roll-formed web foot component may be non-planar as a result of the varying geometry of the web foot component along its length.

[0051] Actuating a pair of actuated rollers between a first position and a second position may comprise pivoting the pair of rollers and / or translating the pair of rollers from the first position to the second position. The second position is different from the first position such that at least one of the first or second portion of the strip is directed along a different path with the pair of rollers in the second position compared to the first position. A section of the web foot component formed by a pair of rollers in the first position will have a different inclination angle between the base and upstand compared to a section of the web foot component formed with the pair of rollers in the second position.

[0052] Actuating the at least one pair of rollers during the roll forming process means that a respective web foot component may comprise a plurality of different inclination angles along the length of the component.

[0053] Notably, the web foot component may be roll formed with a varying inclination angle that corresponds to the varying angle between the web panel and the surface to which the shear web is attached. A web foot component comprising a varying inclination angle may be particularly advantageous for use in a trailing edge stringer or shear web.

[0054] Different wind turbine blades may feature different twist distributions, particularly in blades for different wind classes and blades of different lengths. The variation of the angle defined between the web panel and the surface to which the shear web is attached may be unique to each different wind turbine blade design. To optimise attachment of the shear web to the given surface, web foot components for each different wind turbine design may feature different varying inclination angles corresponding to the respective blade design. Use of the roll forming apparatus, and examples of the method, may facilitate the manufacture of various different web foot components, each having a different twist progression, i.e. different varying inclination angle, using the same roll forming apparatus. The method may be advantageous for saving space in a manufacturing facility whilst still facilitating manufacture of a plurality of different shear web designs for a plurality of different blades.

[0055] In some examples, the at least one roller may be configured to roll form the strip of material into a pre-bent elongate roll-formed web foot component. For example, the first and second portions of the strip may be bent relative to one another in a first plane, and the at least one roller may be further configured to bend the strip of material and / or the roll-formed web foot component in a second plane different to the first plane. Such an example of the method may be advantageous for forming a web foot component for a web foot that closely follows the curvature of a wind turbine blade shell and / or spar components along the length of the blade.

[0056] In some examples, the elongate roll-formed web foot component may be at least 5 m long. Preferably, the elongate roll-formed web foot component may be at least 10 m long. More preferably the elongate roll-formed web foot component may be at least 15 m long. In some examples, the elongate roll-formed web foot component may have a length of at least 25% of the total length of the resultant wind turbine blade shear web. Preferably the elongate roll-formed web foot component may have a length of at least 50% of the total length of the resultant wind turbine blade shear web. More preferably the elongate roll-formed web foot component may have a length of at least 75% of the total length of the resultant wind turbine blade shear web.

[0057] In some examples, the elongate roll-formed web foot component may have a length substantially equivalent to the total length of the resultant wind turbine blade shear web. For example, the elongate web foot may comprise a roll-formed web foot component that extends longitudinally from a first end of the shear web to an opposing second end of the shear web.

[0058] In some examples, the elongate web panel of the wind turbine blade shear web may be formed of a plurality of elongate web panel components. In such examples, the elongate roll-formed web foot component may have a length that is greater than or equal to a respective web panel component to which it is attached. In some examples, the elongate roll-formed web foot component may have a length greater than or equal to the combined length of the plurality of elongate web panel components forming the elongate web panel of the wind turbine blade shear web. In some examples the method may comprise attaching a web foot component to a plurality of elongate web panel components.

[0059] In some examples, the method may further comprise providing an additional strip of material comprising a plurality of plies comprising reinforcing fibres. The plurality of plies in the additional strip of material may be arranged in a stack. The method may further comprise roll forming the additional strip of material into an additional elongate roll-formed web foot component having the plurality of plies arranged in a layered structure and comprising a base and an upstand extending substantially transverse to the base. Roll forming the additional strip of material may comprise applying heat to the additional strip of material. Roll forming the additional strip of material may comprise feeding the additional strip of material through at least one roller which bends a first portion of the additional strip relative to a second portion of the additional strip such that the first portion extends substantially transverse to the second portion, the first portion thereby defining at least part of the upstand of the additional roll-formed web foot component and the second portion thereby defining at least part of the base of the additional roll-formed web foot component. The method may further comprise attaching the upstand of the roll-formed web foot component to the upstand of the additional roll-formed web foot component such that the bases of the web foot component and additional web foot component extend away from one another.

[0060] For example, the web foot component and additional web foot component may be considered to be attached together back to back. In some examples, the upstand of the roll-formed web foot component may be attached to the upstand of the additional roll-formed web foot component such that the bases of the web foot component and additional web foot component are substantially co-planar. The resultant profile of the web foot components attached back to back may be substantially T-shaped.

[0061] In some examples, the at least one roller through which the additional strip of material is fed comprises a series of rollers.

[0062] In some examples, the method may comprise roll forming the web foot component and the additional web foot component simultaneously. For example, the web foot component and the additional web foot component may be manufactured in the same manufacturing facility and / or same manufacturing apparatus. It will be appreciated that in examples where the web foot component and the additional web foot component are simultaneously roll formed, each web foot component may be roll formed by a respective at least one roller.

[0063] In some examples, the strip of material and the additional strip of material may be roll formed simultaneously to form the web foot component and the additional web foot component and attach the respective upstands together. Such examples may be advantageous for reducing manual handling of the web foot components and thereby increasing the manufacturing efficiency and throughput of a manufacturing facility.

[0064] In some examples, the method may further comprise providing a base strip of material comprising reinforcing fibres. The method may comprise roll forming the base strip of material with the strip of material and the additional strip of material such that the base strip of material is arranged to extend across at least a portion of the base of each of the web foot component and the additional web foot component. For example, the base strip of material may form at least part of a base layer of the elongate web foot. The base strip of material may define a mounting surface of the elongate web foot configured for attachment to a spar component and / or an interior surface of a wind turbine blade shell.

[0065] In some examples, the base strip of material may include a peel ply layer. A peel ply layer may facilitate improved adhesion between the web foot of the shear web and the blade shell or other spar components in examples where the web is bonded to such other components. In some examples providing a base strip of material may comprise unwinding the base strip of material from a base strip spool. The base strip of material may comprise a different material compared to the or each strip of material forming a respective web foot component.

[0066] In some examples, the method may comprise arranging a filler material between the strip of material and the additional strip of material before the roll forming process such that feeding the strip of material and the additional strip of material through the respective at least one roller simultaneously roll forms the filler material between the strip of material and the additional strip of material. The filler material may be arranged to fill an elongate volume defined between a radiused junction of the web foot component and a radiused junction of the additional web foot component. Roll forming the filler material at the same time as the strip of material and the additional strip of material may reduce the risk of wrinkles and / or kinks forming in the strips of material during the roll forming process. In some examples, the filler material may be a polymer foam material, a chopped fibre infill, or a rope comprising fibre material.

[0067] In some examples, the method may further comprise trimming the roll-formed web foot component to achieve a desired base width and / or upstand height along its length. Trimming may be performed by integrating a cutting unit into the roll-forming apparatus. For instance, one or more rotary knives, fibre-scissors, or similar cutting tools may be positioned adjacent to the rollers to continuously cut excess material from the web foot during or immediately after roll forming. The cutting tools may be mounted on actuators and guided by a linear positioning system to cut base and / or upstand accurately. In some examples, a slewing ring or equivalent mechanism may be used to adjust the cutting angle relative to the web foot profile. This automated trimming process ensures precise dimensional control, reduces material waste, and facilitates a perfect fit of the shear web within the blade.

[0068] In some examples, the method may further comprise providing identification markings on the roll-formed web foot component. Such markings may include engraved or printed information, such as a QR code, barcode, or alphanumeric identifier, applied to the surface of the web foot during or after the roll-forming process. The identification marking may be used fortraceability, quality control, and integration with digital manufacturing systems. In preferred examples, the marking process may be automated and integrated into the production line, ensuring that each component carries a unique identifier without compromising structural integrity. The QR code or similar marking may be positioned on a non-critical surface of the web foot to facilitate scanning during assembly and maintenance.

[0069] Brief description of the drawings

[0070] Examples of the present invention will now be described by way of non-limiting example only, with reference to the accompanying figures, in which:

[0071] Figure 1 is a schematic perspective view of a wind turbine blade comprising a shear web;

[0072] Figure 2 is a simplified schematic view of roll forming apparatus configured to roll form a web foot component of the shear web;

[0073] Figures 3a, 3b and 3c show examples of roller configurations at different stations in the roll forming apparatus; Figure 4 shows a schematic perspective view of an elongate roll-formed web foot component;

[0074] Figure 5a shows a station in the roll forming apparatus with a pair of actuated rollers in a first position;

[0075] Figure 5b shows the station in the roll forming apparatus with the pair of actuated rollers moved into a second position;

[0076] Figure 6a is a schematic perspective view of the web foot component and web panel component arranged on a shear web mould;

[0077] Figure 6b is a schematic cross-sectional view of the web foot component and a web panel layup on the shear web mould; and

[0078] Figures 7a to 7d show a roll forming process in an example comprising two web foot components arranged back-to back.

[0079] Detailed description

[0080] Figure 1 shows a schematic exploded view of a wind turbine blade 10. As described by way of background, wind turbine blades 10 typically include an outer shell supported by a spar structure. In the example shown in Figure 1, the outer shell is formed of first and second half shells 12a, 12b. The spar structure includes a longitudinally extending shear web 14. The shear web 14 comprises an elongate web panel 16 and an elongate web foot 18. The web foot 18 is preferably configured to facilitate attachment of the shear web 14 to the outer shell, or to a spar cap 20 associated with the outer shell.

[0081] Examples of a method of making a shear web 14 will now be described with reference to the remaining figures. Notably, in each example the method includes a roll forming process to form an elongate roll-formed web foot component 22 which forms at least part of the elongate web foot 18 of the shear web 14.

[0082] Referring initially to Figure 2, this shows a simplified schematic view of roll forming apparatus 24 configured to form an elongate web foot component 22. The method of making the shear web 14 includes providing a strip of material 26. The strip of material 26 includes a plurality of plies 28 arranged in a stack, and the plies 28 comprise reinforcing fibres. For example, the plies 28 may comprise glass reinforcing fibres. In some examples, the plies 28 may comprise dry fibrous material and an uncured binder (not shown) may be provided between adjacent plies 28 in the stack.

[0083] The strip 26 is roll-formed into an elongate roll-formed web foot component 22 which has the plurality of plies 28 arranged in a layered structure. As shown most clearly in Figure 4, the elongate roll-formed web foot component 22 comprises a base 30 and an upstand 32 extending substantially transverse to the base 30. For example, the web foot component 22 may have a substantially L-shaped cross-sectional profile.

[0084] The strip of material 26 is fed through a series of rollers 34 which roll form the strip 26 into a web foot component 22. Figures 3a to 3c show the strip 26 at different stations along the series of rollers 34. By way of example, the strip of material 26 may be fed through a first station as shown in Figure 3a, through a subsequent second station as shown in Figure 3b, and through a subsequent third station as shown in Figure 3c. It should be appreciated that the examples of the first, second and third stations are only shown by way of example, and the series of rollers 34 may comprise any number of stations and any number of rollers 34 configured to roll form the web foot component 22.

[0085] The series of rollers 34 is configured to bend a first portion 36a of the strip 26 relative to a second portion 36b of the strip 26. The rollers 34 bend the strip 26 such that the first portion 36a extends substantially transverse to the second portion 36b. For example, an inclination angle X may be defined between the first portion 36a and the second portion 36b. For any given point along the strip of material 26, the inclination angle X at that point may be altered incrementally by consecutive rollers 34 when the strip 26 is fed through the series of rollers 34, as shown in the progression from Figure 3a to 3c.

[0086] With reference additionally to Figure 4, following the roll forming process, the first portion 36a of the strip 26 defines at least part of the upstand 32 of the roll-formed web foot component 22 and the second portion 36b defines at least part of the base 30 of the roll-formed web foot component 22. As shown, in some examples, the roll forming apparatus 24 may be configured to form an elongate web foot component 22 having a substantially constant inclination angle X along its length. Alternatively, in some other examples the roll forming apparatus 24 may be configured to form a web foot component 22 that has an inclination angle X that varies along its length, as will now be described with reference to Figures 5a and 5b.

[0087] Figure 5a shows an additional example of a strip of material 26 fed through a series of rollers 34. In some examples the series of rollers 34 may include at least one pair of actuated rollers 34a, i.e. a pair of rollers 34 that can be moved, such as by pivoting or translating, during the roll forming process. The actuated rollers 34a may be moveable between a first position, as shown in Figure 5a for example, and a second position such as that shown in the example of Figure 5b. In some examples the pair of actuated rollers 34a may be moved between the first and second positions whilst feeding the strip of material 26 through the series of rollers 34. This forms a web foot component 22 which has an inclination angle X that varies along its length. The varying inclination angle may be continuously changing along the length of the web foot. For example, a section of the web foot component may be formed with the actuated rollers 34a in the first position in Figure 5a, and during the roll forming process the actuated rollers 34a may be moved to the second position in Figure 5b such that a subsequent section of the same web foot component 22 is formed by the actuated rollers 34a in the second position.

[0088] With reference to each of the examples described herein, the method also includes applying heat to the strip of material 26. For example, the roll forming apparatus 24 may comprise heating apparatus 37. In some examples, heat may be applied to the strip 26 before the roll forming process to increase flexibility of the strip 26. As described previously, in some examples a binder may be included between the stacked plies 28 in the strip 26. The method may include at least partially curing the binder after the strip of material 26 is fed through the series of rollers 34 in the roll forming process. This may help to secure the plies 28 together to form a pre-formed elongate roll-formed web foot component 22 which is geometrically stable for further processing.

[0089] The roll forming process has been described with reference to the examples of Figures 2 to 5b. To make the wind turbine blade shear web 14, the elongate roll-formed web foot component 22 is attached to an elongate web panel component 38 which is preferably shaped to form at least part of the elongate web panel 16 of the shear web 14. As will now be described with reference to the examples of Figures 6a and 6b, the upstand 32 of the elongate roll-formed web foot component 22 is attached to the elongate web panel component 38.

[0090] In some examples, the roll-formed web foot component 22 may be attached to the web panel component 38 in a co-infusion and curing process. This may be particularly applicable in examples where the web foot component 22 comprises a pre-form of dry fibrous material. The method may include arranging a pre-formed elongate roll-formed web foot component 22 on or in a shear web mould 40, and additionally arranging a composite layup 42 comprising the elongate web panel component 38 in the shear web mould 40. For example, the upstand 32 and the web panel component 38 may be arranged on a longitudinally-extending main surface 44 of the mould 40 that is shaped to form at least part of the elongate web panel 16. The pre-formed dry fibre web foot component 22 and the composite layup 42 may be co-infused with a resin (not shown), and the resin may then be cured to attach the web foot component 22 to the web panel component 38.

[0091] The schematic cross-sectional view in Figure 6b shows an example of the composite layup 42 in more detail. The composite layup 42 may include the web panel component 38 and one or more layers of fibrous material 46. Arranging the layup 42 on the mould 40 may therefore include arranging the elongate web panel component 38 and one or more layers of fibrous material 46 on the main surface 44 of the mould 40. The upstand 32 of the roll-formed web foot component 22 may be arranged on the main surface 44 on top of or under at least one layer of fibrous material 46. As shown in the example of Figure 6b, the layup 42 may comprise a sandwich structure in which the web panel component 38, such as core material, is sandwiched between layers of fibrous material 46. In such an example, the upstand 32 of the roll-formed web foot component 22 may be arranged between two or more layers of fibrous material 46.

[0092] As described previously, the method may include co-infusion of the web foot component 22 and the layup 42. For example, uncured resin (not shown) may be provided to the fibrous material 46 on the main surface 44 and between the upstand 32, at least one layer of fibrous material 46, and the web panel component 38. The resin may be cured such that the upstand 32 of the elongate roll-formed web foot component 22 is then attached to the elongate web panel component 38.

[0093] The examples of the shear web manufacturing method described with reference to Figures 2 to 6b include a web foot component 22 having a substantially L-shaped profile. Such a web foot component 22 may form at least part of an elongate web foot 18 having an L-shaped profile. Alternatively, in some other examples, the elongate web foot 18 of the shear web 14 may have a substantially T-shaped profile, as shown in Figure 1. For example, the elongate web foot 18 may comprise two web foot components 22 arranged back to back, as will now be described with reference to Figures 7a to 7d.

[0094] The method may include roll forming an additional strip of material 126 into an additional elongate roll-formed web foot component 122. Description provided previously in relation to the elongate roll-formed web foot component 22 is equally applicable to the additional elongate roll-formed web foot component 122, and will not be repeated here for conciseness. However, to form an elongate web foot 18 with a substantially T-shaped profile, the method may additionally include attaching the upstand 32 of the roll-formed web foot component 22 to the upstand 132 of the additional roll-formed web foot component 122. The upstands 32, 132 may be attached to one another such that bases 30, 130 of the web foot component 22 and additional web foot component 122 extend away from one another, as shown for example in Figures 7c and 7d.

[0095] In some examples, the strip of material 26 and the additional strip of material 126 may be roll formed simultaneously. For example, the web foot component 22 and the additional web foot component 122 may be formed at the same time, and the respective upstands 32, 132 may be attached together in the same process, as shown in the examples of Figures 7a to 7d. These schematic figures show examples of successive stations in roll forming apparatus 124 configured to form the web foot component 22 and the additional web foot component 122 simultaneously and attach the respective upstands 32, 132 together.

[0096] As shown in Figures 7a to 7d, in some examples, a filler material 48 may be arranged between the strip of material 26 and the additional strip of material 126 before the roll forming process. By feeding the strip of material 26 and the additional strip of material 126 through the respective series of rollers 34, 134, the filler material 48 may be simultaneously roll formed between the strip of material 26 and the additional strip of material 126. The filler material 48 may fill an elongate volume between a radiused junction 50 of the web foot component 22 and a radiused junction 150 of the additional web foot component 122. This may help prevent wrinkles and / or kinks forming in the strips of material 26, 126 during the roll forming process.

[0097] With reference in particular to Figure 7d, the method may also include providing a base strip of material 52 comprising reinforcing fibres, in some examples. The base strip of material 52 may be introduced to the roll forming apparatus 124 and roll formed simultaneously with the strip of material 26 and the additional strip of material 126. In particular, the base strip 52 may be roll formed to extend across at least a portion of the base 30, 130 of each of the web foot component 22 and the additional web foot component 122. Such a base strip 52 may provide an advantageous surface for bonding the resultant elongate web foot 18 of the shear web 14 to the blade shell or other spar components. It should be appreciated that many modifications may be made to the examples described herein and shown in the accompanying figures without departing from the scope of the invention defined in the claims.

[0098] For example, examples of the method have been described with reference to roll forming a strip of material 26, 126 comprising dry fibrous material. However, in some examples the strip of material 26, 126 may comprise pre-preg fibrous material that is pre-impregnated with resin prior to the roll forming process. Features of the method described herein are equally applicable to roll forming a strip of material 26, 126 comprising pre-preg fibrous material.

[0099] Further, in some examples, the strip of material 26, 126 may comprise a fibre-reinforced thermoplastic material. In such an example, the method may include a thermoplastic welding process after feeding the strip of material 26, 126 through the series of rollers 34, 134. In the thermoplastic welding process, a plurality of plies 28 comprising fibre-reinforced thermoplastic material may be fused together. This may form a substantially finished component which is geometrically stable and ready for attachment to the web panel component 38. For example, a web foot component 22, 122 comprising fibre-reinforced thermoplastic material may be thermally welded to the web panel component 38, in some examples.

[0100] In some other examples, the web foot component 22, 122 may be attached to the web panel component 38 by bonding the upstand 32, 132 to the web panel component 38 using adhesive. Alternatively, the method may include a co-bonding process in which the upstand 32, 132 is attached to the web panel component 38 at the same time that an uncured layup 42 comprising the web panel component 38 is infused and cured.

[0101] Whilst not shown in the accompanying figures, in each of the examples described herein the roll forming apparatus 24, 124, including the series of rollers 34, 134, may be arranged in line with the shear web mould 40. Such an arrangement means that the elongate roll-formed web foot component 22, 122 can be extracted from the roll forming apparatus 24, 124 and deposited directly into the shear web mould 40. This simplifies handling of the web foot component 22, 122 during manufacture of the shear web 14.

[0102] The method has been described in relation to attaching a web foot component 22 to the web panel component 38, or attaching two back-to-back web foot components 22, 122 to the web panel component 38 in the example of a T-shaped web foot 18. For example, the elongate web foot 18 of the shear web 14 may comprise a single web foot component 22 extending along the full length of the shear web 14, or two back-to-back web foot components 22, 122 extending along the full length of the shear web 14. However, it should be appreciated that in some examples, the method may include arranging a plurality of elongate roll-formed web foot components 22, 122 end to end and attaching these to one or more web panel components 38 to form the shear web 14.

[0103] In some preferred examples, the or each elongate roll-formed web foot component 22, 122 may be at least 5 m long, preferably at least 10 m long, and more preferably at least 15 m long. The elongate roll-formed web foot component 22, 122 may have a length of at least 25%, preferably at least 50%, and more preferably at least 75% of the total length of the resultant shear web 14. This reduces the number of shear web components required for manufacturing the shear web 14, thereby reducing assembly time and improving throughput of the manufacturing facility.

[0104] The Figures above and the associated description describe feeding a strip of material through a series of rollers. However, this is merely an example and the method may comprise any suitable number of rollers. For example, there may just be a single roller, such as at least one roller.

[0105] The description provided herein serves to demonstrate a plurality of possible examples of the present invention. Features described in relation to any of the examples above may be readily combined with any other features described with reference to different examples without departing from the scope of the invention as defined in the appended claims.

Claims

Claims1. A method of making a wind turbine blade shear web comprising an elongate web panel and an elongate web foot, the method comprising:providing an elongate web panel component;providing a strip of material comprising a plurality of plies comprising reinforcing fibres, the plurality of plies being arranged in a stack;roll forming the strip of material into an elongate roll-formed web foot component having the plurality of plies arranged in a layered structure and comprising a base and an upstand extending substantially transverse to the base;wherein roll forming the strip of material comprises:applying heat to the strip of material; andfeeding the strip of material through at least one roller which bends a first portion of the strip relative to a second portion of the strip such that the first portion extends substantially transverse to the second portion, the first portion thereby defining at least part of the upstand of the roll-formed web foot component and the second portion thereby defining at least part of the base of the roll-formed web foot component; andattaching the upstand of the elongate roll-formed web foot component to the elongate web panel component.

2. The method of any preceding claim, wherein the plies comprise dry fibrous material and an uncured binder provided between adjacent plies in the stack.

3. The method of claim 2, further comprising at least partially curing the binder after the strip of material is fed through the at least one roller to secure the plies comprising reinforcing fibres together to form a pre-formed elongate roll-formed web foot component.

4. The method of any preceding claim, wherein the plurality of plies comprise a fibre-reinforced thermoplastic material.

5. The method of claim 4, further comprising a thermoplastic welding process after feeding the strip of material through the at least one roller, wherein the thermoplastic welding process comprises fusing the plurality of plies of fibre-reinforced thermoplastic material together.

6. The method of claim 5, wherein attaching the upstand of the elongate roll-formed web foot component to the elongate web panel component comprises at least one of thermoplastic welding, adhesive bonding, or co-bonding the upstand to the elongate web panel component.

7. The method of claim 3, further comprising arranging the pre-formed elongate roll-formed web foot component in a shear web mould, arranging a composite layup comprising the elongate web panel component in the shear web mould, co-infusing the pre-formed elongate roll-formed web foot component and the composite layup with a resin, and curing the resin.

8. The method of any preceding claim, wherein roll forming apparatus including the at least one roller is arranged in line with a shear web mould, and wherein the method comprises extracting the elongate roll-formed web foot component from the roll forming apparatus and depositing the web foot component directly into the shear web mould.

9. The method of any preceding claim, further comprising:providing a shear web mould comprising a longitudinally-extending main surface shaped to form at least part of the elongate web panel;arranging one or more layers of fibrous material on the main surface; arranging the elongate web panel component on the main surface; arranging the upstand of the elongate roll-formed web foot component on the main surface on top of and / or under at least one layer of fibrous material; providing uncured resin to the fibrous material on the main surface and between the upstand, the at least one layer of fibrous material, and the web panel component; andcuring the uncured resin to thereby attach the upstand of the elongate roll- formed web foot component to the elongate web panel component.

10. The method of any preceding claim, wherein the at least one roller comprises at least one pair of actuated rollers, and wherein the method comprises actuating the at least one pair of actuated rollers between a first position and a second position whilst feeding the strip of material through the at least one roller.

11. The method of any preceding claim, wherein the elongate roll-formed web foot component is at least 5 m long, preferably at least 10 m long, and more preferably at least15 m long, and / or wherein the elongate roll-formed web foot component has a length of at least 25%, preferably at least 50%, and more preferably at least 75% of the total length of the resultant wind turbine blade shear web.

12. The method of any preceding claim, wherein the at least one roller comprises a series of rollers.

13. The method any preceding claim, further comprising:providing an additional strip of material comprising a plurality of plies comprising reinforcing fibres, the plurality of plies being arranged in a stack;roll forming the additional strip of material into an additional elongate roll-formed web foot component having the plurality of plies arranged in a layered structure and comprising a base and an upstand extending substantially transverse to the base;wherein roll forming the additional strip of material comprises:applying heat to the additional strip of material; andfeeding the additional strip of material through at least one roller which bends a first portion of the additional strip relative to a second portion of the additional strip such that the first portion extends substantially transverse to the second portion, the first portion thereby defining at least part of the upstand of the additional roll-formed web foot component and the second portion thereby defining at least part of the base of the additional roll-formed web foot component; attaching the upstand of the roll-formed web foot component to the upstand of the additional roll-formed web foot component such that the bases of the web foot component and additional web foot component extend away from one another.

14. The method of claim 13, wherein the strip of material and the additional strip of material are roll formed simultaneously to form the web foot component and the additional web foot component and attach the respective upstands together.

15. The method of claim 14, further comprising providing a base strip of material comprising reinforcing fibres, and roll forming the base strip of material with the strip of material and the additional strip of material such that the base strip of material is arranged to extend across at least a portion of the base of each of the web foot component and the additional web foot component.

16. The method of claim 14 or claim 15, further comprising arranging a filler material between the strip of material and the additional strip of material before the roll forming process such that feeding the strip of material and the additional strip of material through the respective at least one rollers simultaneously roll forms the filler material between the strip of material and the additional strip of material.

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