Patent Application
20240052802
The present invention relates to a method of manufacturing a wind turbine blade or blade shell member comprising a pre-manufactured spar cap and a number of pre-impregnated fibre sheets. The present invention also relates to a wind turbine blade or blade shell member obtainable by the methods disclosed and to a pre-impregnated fibre sheet.
The blades of modern wind turbines capture kinetic wind energy by using sophisticated blade design created to maximise efficiency. A major trend in wind turbine development is the increase in size to reduce the leveraged cost of energy. There is an increasing demand for large wind blades which may exceed 80 metres in length and 4 metres in width. The blades are typically made from a fibre-reinforced polymer material and comprise a pressure side shell half and a suction side shell half. The cross-sectional profile of a typical blade includes an airfoil for creating an air flow leading to a pressure difference between the two sides. The resulting lift force generates torque for producing electricity.
The shell halves of wind turbine blades are usually manufactured using blade moulds. First, a blade gel coat or primer is applied to the mould. Subsequently, fibre reinforcement material is placed into the mould in layers followed by arrangement of other elements within the shell halves, such as core elements, load-carrying spar caps, internal shear webs and the like. The resulting shell halves are resin infused and assembled by being glued or bolted together substantially along a chord plane of the blade.
The spar caps comprise a plurality of carbon pultrusion elements and interlayers arranged between the carbon pultrusion elements. The spar caps may be produced directly in the wind turbine blade moulds or in a separate offline mould where they are resin infused and then subsequently lifted into the main blade shell mould which is then infused with resin.
Different combinations of resins may be used for the spar cap and the main blade shell. It is very important to ensure a sufficiently strong adhesion between the shell and the pre-manufactured spar cap since bonding of resin onto the spar cap is crucial for the structural integrity of the blade. Vinyl ester or epoxy ester resins have good adherence properties and are often used, whereas other resins, such as polyester resin, have an attractive price. However, the adhesion properties of polyester resin are low compared to vinyl ester and epoxy resin.
The use of a primer on the spar cap increases the adherence properties at the resin interface between the spar cap and remaining parts of the blade shell member. Although the primer enhances the adhesion, it is not easy to apply and control.
Where the spar cap is made offline, primer may be applied to all surfaces of the spar cap before it is placed in the blade mould. However, to apply primer on all surfaces of the pre-manufactured spar cap before it is placed in the blade mould is challenging for several reasons. In practice, it is especially hard to apply the primer on the bottom of the pre-manufactured spar cap since the spar cap needs to be turned upside down to be able to apply primer to the bottom surface. Secondly, the spar cap needs to be lifted onto the blade mould after appliance of primer. To lift the spar cap, a sling may be arranged around the spar cap. However, the sling may damage some of the primed surfaces during lifting and thus decrease the adherence and strength of the finished structure. Furthermore, the primer may be based on isocyanate chemistry and react with moisture. Thus, its effect is reduced over time, especially at high humidities. Thus, the time from appliance of the first primer layer to the time of resin infusion is critical, and a prolonged processing time may affect the primer properties and the structural integrity of the blade.
Hence, improved methods to ensure a sufficiently strong adhesion between the shell member parts and the pre-manufactured spar cap would be advantageous.
It is an object of the present disclosure to provide an improved method of manufacturing a blade shell member and wind turbine blade comprising a pre-manufactured spar cap resulting in a blade shell member or wind turbine blade having sufficiently strong adhesion between the blade shell member parts and the pre-manufactured spar cap and a reduced manufacturing time, particularly when the pre-manufactured spar cap is resin infused with vinyl ester or epoxy resin and the blade mould is resin infused with polyester.
The present inventors have found that one or more of said objects may be achieved by arranging a pre-impregnated fibre sheet according to a first aspect of the present invention at the interface between the pre-manufactured spar cap and the remaining parts of the blade shell member.
According to the first aspect of the invention, the pre-impregnated fibre sheet extends in a longitudinal direction and in a transverse direction and comprises a first fibre layer forming part of an upper surface of the pre-impregnated fibre sheet and a second fibre layer forming part of a lower surface of the pre-impregnated fibre sheet, wherein the first fibre layer is pre-impregnated with an adhesion promotor. Preferably, the second fibre layer is not pre-impregnated with the adhesion promotor.
The pre-impregnated fibre sheet is configured to be arranged at the interface between the pre-manufactured spar cap and the remaining blade shell member parts, with the pre-impregnated fibre layer, i.e. the first fibre layer facing the spar cap and the second fibre layer facing the remaining blade shell member parts. The first fibre layer comprising the adhesion promotor will then facilitate adherence between the spar cap and the pre-impregnated fibre sheet, whereas the second fibre layer can easily adhere to the remaining blade shell member parts during resin infusion. Preferably, the pre-impregnated fibre sheet is a biaxial glass fibre sheet. Thus, by arranging the pre-impregnated fibre sheet at the interface between the spar cap and the blade shell members, the problem of adherence between the blade shell members and the spar cap is avoided.
As used herein, the term “adhesion promotor” is intended to encompass any compound or group of compounds that facilitates permanent contact between the pre-manufactured spar cap and the remaining parts of the blade shell member.
In some embodiments, the adhesion promotor is anything that positively influences the adhesion step between the between the pre-manufactured spar cap and the remaining parts of the blade shell member. In some embodiments, the adhesion promotor facilitates the resin flow/wetting of the pre-impregnated fibre sheet. In some embodiments, adhesion promotor makes the chemical bonding between the pre-manufactured spar cap and the remaining parts of the blade shell member faster and/or stronger.
In some embodiments, the adhesion promoter acts by forming an at least partial attractive force on a molecular or atomic level between the pre-manufactured spar cap and the remaining parts of the blade shell member. Examples of attractive forces include covalent bonds, polar covalent bonds, ionic bonds, hydrogen bonds, electrostatic attractions, hydrophobic interactions, and van der Waals attractions. That is, a functionality on an adhesion promoter group can form an attractive interaction with a functionality on the remaining parts of the blade shell member.
In some embodiments, the adhesion promoter comprises chemicals that act at the interface between the pre-manufactured spar cap and the remaining parts of the blade shell member to chemically and physically wed these dissimilar materials into a strong cohesive bond structure.
In some embodiments, the adhesion promoter comprise chemical materials that contain dual functionality in the molecular structure. A metallic central atom, such as silicon, zirconium, titanium, aluminum, or others, will give inorganic reactivity to the adhesion promoter, especially if methoxy, ethoxy, or hydroxyl groups are attached to the metal atom. An organofunctional group can also be attached to the metal atom through an alkylene, arylene, or other type of organic bridge, to give traditional organic reactivity to the adhesion promoter. The inorganic reactive groups can condense with themselves to give the adhesion promoter an oligomeric structure. An oligomeric adhesion promoter has dual- or multi-functionality and structural integrity, such that a stable chemical bond occurs between the dissimilar organic and inorganic surfaces to promote adhesion between the two dissimilar materials. This basic concept of the chemistry and action of adhesion promoters has allowed great advances in reinforced plastics, adhesive bonding, and compatibilization of different materials in a wide variety of applications.
In some embodiments, the adhesion promoter include reactive organic oligomers or polymers, such as thermoplastics polymers (polyethylene, polypropylene, etc.) grafted with organofunctional groups. The adhesion promoter may include block copolymers that function by having polymeric segments with solubility parameters that are matched to the components in order to be adhered or compatibilized and function by atomic interactions of van der Waals, dipole interaction, and other atomic forces. Organosilane coupling agents are a predominant chemical type of adhesion promoter.
In some embodiments, the adhesion promotor is a powder. In some embodiments, the adhesion promotor is a liquid solution.
In some embodiments, the adhesion promotor is compatible with polyester resin and/or epoxy ester resin and/or vinyl ester resin. In some embodiments, the adhesion promotor is a primer and/or is isocyanate based and/or silane based and/or acrylate based and/or urethane based. A suitable adhesion promotor would be SIKA215. SIKA215 is urethane and isocyanate based.
The adhesion promoter may be based on reactive silanes containing both organofunctional and hydrolyzable groups. These silanes are added at about 0.2-3% by weight, based on the total formulation in order to achieve self-priming adhesion characteristics. Upon cure, the adhesion promoter participates in the cross-linking reactions, but also establishes bonds between the silicone network and the substrate. All the art and technology of a self-priming polymeric system resides in the choice and chemical design of the adhesion promoter molecules. Silane coupling agents are denoted by the general structure RSiX3, where R is a reactive organofunctional group and X is a hydrolyzable group, such as a methoxy, ethoxy or acetoxy group. The variety of different organosilanes and their respective merits have been discussed in detail elsewhere. Organosilanes are small, surface-active molecules, which easily can diffuse to the interlace at the same time that cross-linking occurs in the bulk of the silicone composition. Once at the interface, they can improve adhesion through enhanced wetting and covalent bonding. Hydrolysis of the organosilane provides active silanol sites for hydrogen bonding. The silanol groups on the organosilane allow condensation reactions to occur, which result in the formation of Si—O—Si bonds between the silane molecule and the silicon-containing surface as well as the silicone network. It also is possible for the organofunctional group on the silane to react with chemical reactive groups present in the substrate surface. Silanes are particularly effective in the promotion of adhesion of silicones to metal, glass and siliceous surfaces in general. A recent study has shown that specific mixtures of silanes can provide better adhesive performance than the separate silanes and that an optimum composition is required. Suitable classes of adhesion promoters for condensation-cure rtV systems are functional silanes bearing aminoalkyl, mercaptoalkyl, epoxyalkyl, ureidoalkyl, acrylate and isocyanurate groups. Within these classes, the commercially most important adhesion promoters are aminopropyltriethoxysilane, aminoethylaminopropyltrimethoxysilane and glycidoxypropyltrimethoxysilane. Novel and more complex adhesion promoter systems are continually being developed to respond to the demands of emerging and future sealing and bonding technologies.
In some embodiments, the first fibre layer comprises a first plurality of fibres arranged along a first fibre direction, and the second fibre layer comprises a second plurality of fibres arranged along a second fibre direction.
In some embodiments, the first and second fibre directions are different.
In some embodiments, a fibre angle between the first and second fibre directions is between 40 degrees and 150 degrees, preferably 90 degrees.
In some embodiments, the arrangement of the first plurality of fibres and the arrangement of the second plurality of fibres are maintained relative to each other in the pre-impregnated fibre sheet by a plurality of stitching rows.
In some embodiments, the plurality of stitching rows is parallel and arranged along a first stitch direction.
In some embodiments, the first stitch direction is between the first and second fibre directions, such as half the fibre angle from each of the first and second fibre directions.
In some embodiments, the first and/or second plurality of fibres comprises or essentially consists of glass fibres.
In some embodiments, the first and second fibre layers are arranged on top of each other, i.e. being in contact with each other.
In preferred embodiments, the pre-impregnated fibre sheet is a biaxial glass-fibre sheet, wherein the first and second fibre directions are each arranged at a 45-degree angle relative to a longitudinal direction of the pre-impregnated fibre sheet, the fibre angle between the first and second fibre directions is 90 degrees, and the first stitch direction is parallel with the longitudinal direction of the pre-impregnated fibre sheet.
In some embodiments, the pre-impregnated fibre sheet further comprises at least one further fibre layer, such as a third fibre layer and/or a fourth fibre layer etc., arranged between the first and second fibre layers and each comprising a plurality of fibres arranged along a third, fourth etc. fibre direction, which may be the same or different between these fibre layers and/or the same or different from the first and/or second fibre directions.
In some embodiments, the adhesion promotor is applied to the upper surface of the pre-impregnated fibre sheet i.e. to the first fibre layer by brushing and/or rolling and/or spraying it on the first fibre layer. In some embodiments, the adhesion promotor is applied to the first fibre layer by using a spray gun, such as a long-reach spray gun.
In some embodiments, the first plurality of fibres of the first fibre layer is coated by an adhesion promotor e.g. by dipping the first plurality of fibres in a bath comprising the adhesion promotor, before the fibres are stitched together with the second plurality of fibres to provide the pre-impregnated fibre sheet.
In some embodiments, the adhesion promotor is dried and/or heated after appliance to the first plurality of fibres or the first fibre layer of the pre-impregnated fibre sheet.
In some embodiments, the upper surface of the pre-impregnated fibre sheet comprising the first fibre layer is covered by a removable film. In this way, the sheet can be rolled up along the longitudinal direction and be stored in a compact configuration. The film allows the pre-impregnated fibre sheet to be rolled up upon itself, without the first fibre layer comprising the adhesion promoter getting in direct contact with the second fibre layer.
Preferably, the pre-impregnated fibre sheet is configured to have at least the same length as a pre-manufactured spar cap and substantially the same width. Thus, the rolled-up pre-impregnated fibre sheet can easily be rolled out over the entire length of the spar cap. Depending on how the first fibre layer is arranged, i.e. whether it is arranged to face the surface onto which it is rolled out or not, the film covering the upper surface of the first fibre layer can be removed substantially simultaneously with or after the pre-impregnated fibre sheet is rolled out. In case the pre-impregnated fibre sheet is arranged such that the first fibre layer faces the surface onto which it is rolled out, the film should be removed substantially simultaneously with the pre-impregnated fibre sheet being rolled out. However, in case the pre-impregnated fibre sheet is arranged such that the second fibre layer faces the surface onto which the pre-impregnated fibre sheet is rolled out, the film may be removed substantially simultaneously with or after the pre-impregnated fibre sheet being rolled out.
In a second aspect, the present invention relates to a method of manufacturing a blade shell member for a wind turbine blade according to the first aspect of the present disclosure, comprising the steps of:
Since the pre-impregnated fibre sheet has two connected layers with two different properties, one facilitating adherence to the pre-manufactured spar cap and one facilitating adherence to the remaining blade shell member parts during resin infusion, the pre-impregnated fibre sheet facilitates adhesion between the pre-manufactured spar cap and the remaining blade shell member parts. Furthermore, the pre-impregnated fibre sheet increases the fracture toughness of the blade shell member. If the pre-impregnated fibre sheet is designed with a low cohesive strength but a high fracture toughness, an emerging interface crack will always seek to propagate into the pre-impregnated fibre sheet where the crack ideally will arrest or at least slow down in propagation speed. Thus, the pre-impregnated fibre sheet will take over the toughening mechanism and thereby increase the overall fracture toughness of the blade shell member. In this way, sufficient adherence and strength of the blade shell member are obtained. This is especially advantageous, if the pre-manufactured spar cap and the blade shell member are infused with different types of resin.
Also, by arranging the first pre-impregnated fibre sheet on top of the fibre-reinforced layers at the predetermined spar cap region, before arranging the pre-manufactured spar cap in the blade mould, appliance of primer on the bottom of the pre-manufactured spar cap can be avoided. In this way, it is not necessary to turn the spar cap upside down to be able to apply a primer layer to the bottom surface. Furthermore, damage to the primer layer during lifting of the pre-manufactured spar cap from a preparation station to the blade mould is avoided. In this way, improved adherence properties and strength of the finished structure can be obtained.
Furthermore, by arranging the second pre-impregnated fibre sheet on top of the upper surface of the pre-manufactured spar cap, either before or after arranging the spar cap on the spar cap region, primer appliance may be avoided altogether. For example, arrangement of the second pre-impregnated fibre sheet on the upper surface of the pre-manufactured spar cap may be performed simultaneously with arrangement of the first pre-impregnated fibre sheet to the spar cap region, and the pre-manufactured spar cap may be arranged on the blade mould immediately after, hereby decreasing overall manufacturing time.
In some embodiments, the method further comprises the step of applying a primer layer to at least part of the spar cap region before step e). In such embodiments, the method comprises the step of arranging the second pre-impregnated fibre sheet on at least part of the upper surface of the pre-manufactured spar cap before step f) and preferably after step e), but there is no need for the first pre-impregnated fibre sheet.
In some embodiments, the method further comprises the step of applying a primer layer to at least part of the upper surface of the pre-manufactured spar cap before step f). In such embodiments, the method comprises a step of arranging the first pre-impregnated fibre sheet on top of the number of fibre-reinforced layers on at least part of the spar cap region before step e), but there is no need for the second pre-impregnated fibre sheet.
In some embodiments, the primer layer is applied by brushing and/or rolling and/or spraying. In some embodiments, the primer layer is applied by using a spray gun, such as a long-reach spray gun. The primer layer may be applied from the walkway on the side of the blade mould. This will minimise any damage to the materials in the blade mould.
The primer may be applied in the form of a powder or as a solution comprising primer. In some embodiments, the primer layer comprises or consists of SIKA215 primer. The primer layer may be a uniform layer or be an uneven layer, where some parts of the spar cap region or upper surface of the pre-manufactured spar cap comprise primer and other parts comprise less primer or no primer at all.
The spar cap region is to be understood as a region relative to the moulding surface, where the pre-manufactured spar cap is to be arranged. However, the spar cap region is not to be understood as an area of the moulding surface, since the pre-manufactured spar cap is to be arranged on the fibre-reinforced layers arranged on the moulding surface. The spar cap region preferably has the same size as the lower surface of the pre-manufactured spar cap. In some embodiments, the pre-impregnated fibre sheets or primer layers are arranged on or applied to the entire spar cap region or upper surface of the pre-manufactured spar cap. In some embodiments, the pre-impregnated fibre sheets or primer layers are arranged on or applied on one or more areas of the spar cap region or upper surface of the pre-manufactured spar cap, but not on the entire area. In preferred embodiments, the first and/or second pre-impregnated fibre sheet extends beyond the spar cap region and/or upper surface of the pre-manufactured spar cap e.g. it is wider than the spar cap region. This is advantageous as the pre-impregnated fibre sheets then further reinforce the transition between the pre-manufactured spar cap and remaining blade shell member parts, particularly when the pre-impregnated fibre sheets are biaxial glass fibre sheets, since biaxial glass fibre sheets can carry load transversely across the weak connection between the pre-manufactured spar cap and remaining blade shell member parts.
In some embodiments, the number of pre-impregnated fibre sheets comprises a plurality of first pre-impregnated fibre sheets and a plurality of second pre-impregnated fibre sheets, wherein the plurality of first pre-impregnated fibre sheets arranged such that they together cover substantially the entire pre-determined spar cap region and wherein the plurality of second pre-impregnated fibre sheets are arranged such that they together cover substantially the entire upper surface of the pre-manufactured spar cap.
A pre-impregnated fibre sheet or a primer layer may further be applied to the side surfaces and/or end surfaces of the pre-manufactured spar cap. If done, the pre-impregnated fibre sheets or primer layers may be applied to the pre-manufactured spar cap before or after it is arranged in the blade mould. Depending on the method of lifting the pre-manufactured spar cap from a preparation table to the blade mould, it may be advantageous to arrange the pre-impregnated fibre sheets or apply the primer layers after arranging the pre-manufactured spar cap in the blade mould to avoid damages during lifting and to improve the access to the sides and surfaces of the pre-manufactured spar cap.
In some embodiments, the first and/or pre-impregnated fibre sheets are provided in a rolled-up configuration and the upper surface of the pre-impregnated fibre sheets, i.e. the first fibre layer, is covered by a removable film. In such embodiments, the step of arranging the first pre-impregnated fibre sheet and/or second pre-impregnated fibre sheet comprises removing the film while rolling out the pre-impregnated fibre sheets.
In some embodiments, the step of arranging the number of fibre-reinforced layers on the blade moulding surface comprises arranging each of the number of fibre-reinforced layers on top of each other. The fibre-reinforced layers arranged on the blade moulding surface will become the outer shell of the blade shell member. Thus, preferably the fibre-reinforced layers should cover the entire moulding surface. The number of fibre-reinforced layers are between 1-100, preferably between 5-50, such as between 10-40.
In some embodiments, the step of arranging the number of fibre-reinforced layers on the blade moulding surface comprises arranging a plurality of preforms, each comprising a consolidated stack of fibre-reinforced layers, on the moulding surface. Preferably, the plurality of preforms together covers the entire moulding surface. The use of preforms may be advantageous, especially when manufacturing very large blade shell members, since wrinkles in the fibre-reinforced layers may be reduced.
In some embodiments, the method further comprises arranging further fibre-reinforced layers in the blade mould, including arranging further fibre-reinforced layers on top of the second pre-impregnated sheet, before step f) and after step e), such that the further fibre-reinforced layers are contacted with the second fibre layer of the second pre-impregnated sheet.
In some embodiments, the number of fibre-reinforced layers and further fibre-reinforced layers comprises glass fibres and/or carbon fibres. In some embodiments, the number of fibre-reinforced layers and further fibre-reinforced layers comprises unidirectional layers and/or biaxial layers and/or triaxial layers.
In some embodiments, the method further comprises the step of arranging further blade shell member parts, such as sandwich core layers and/or shear webs in the blade mould cavity. The blade shell member parts referred to herein include all parts of the blade shell member.
In some embodiments, providing the pre-manufactured spar cap comprises the steps of:
The pre-manufactured spar cap is preferably an elongated element having an upper surface, a lower surface, a first side surface, a second side surface, a first end surface and a second end surface. The upper surface and lower surface are preferably arranged opposite each other and may have substantially the same sizes. In the same way, the first and second side surfaces may be arranged opposite each other and have substantially the same sizes, and the first and second end surfaces are arranged opposite each other and preferably have substantially the same sizes. However, since the shape of the spar cap is set according to strength requirements, the thickness may change along the longitudinal direction of the spar cap, resulting in tapering sections at the sides and/or the ends.
The pultruded carbon elements are preferably elongated planks with a rectangular cross-section and made from carbon fibres or glass fibres in a cured resin. Alternatively, they may be hybrid pultrusion elements further comprising a second type of reinforcement fibres, such as glass fibres. The interlayers comprise fibre material, such as glass fibres, carbon fibres or polymeric fibres etc. for promoting resin flow between the pultruded carbon planks.
In some embodiments, the pre-manufactured spar cap is infused with vinyl ester or epoxy ester resin to connect the pultruded carbon elements. Preferably, the blade mould cavity is infused with polyester resin.
Polyester resin is much cheaper than conventionally used resins, such as epoxy ester and vinyl ester. However, the fracture resistance of polyester-infused blade shell member parts is significantly lower than the fracture toughness of a vinyl ester or epoxy ester infused blade shell member. The adherence properties and strength of the pre-manufactured spar cap are particularly important. Thus, even though the prices of vinyl ester or epoxy ester are high compared to other resins, these are preferred for the pre-manufactured spar cap. By primarily using polyester resin for the remaining blade shell member and only using vinyl ester or epoxy ester resin for a few parts, such as the pre-manufactured spar cap, the costs of the blade shell member can be greatly reduced. Recent testing shows that the fracture toughness at the interface between a pre-manufactured spar cap infused with vinyl ester resin and the remaining blade shell member part infused with polyester resin is low. Furthermore, the fracture resistance of the polyester infused blade shell member parts is significantly lower than the fracture toughness of the vinyl ester or epoxy ester spar cap. Therefore, any cracks starting at the interface will probably propagate into the interface or kink into the polyester infused blade shell member parts having a lower fracture toughness than the vinyl ester or epoxy ester spar cap. However, with the arrangement of the pre-impregnated fibre sheet as disclosed herein at the interface between pre-manufactured spar cap and the remaining blade shell member parts, the fracture toughness at the vinyl ester resin/polyester resin interface can be increased. Furthermore, the use of a pre-impregnated layer increases the fracture toughness of the polyester-infused blade shell member itself, meaning that if a crack starts at the interface it may arrest if it tries to propagate into the pre-impregnated fibre sheet. If the pre-impregnated fibre sheet is designed with a low cohesive strength but a high fracture toughness, then the interface crack will always seek to propagate into the pre-impregnated fibre sheet where the crack ideally will arrest or at least slow down in propagation speed. Thus, the pre-impregnated fibre sheet will take over the toughening mechanism and thereby increase the overall fracture toughness of the blade shell member. In this way, sufficient adherence and strength of the blade shell member are obtained at a reduced price by using a pre-impregnated sheet according to the present invention.
In some embodiments, the step of infusing the blade mould cavity with resin is based on vacuum-assisted resin transfer moulding (VARMT). When the desired elements have been arranged in the blade mould, a vacuum bag may be arranged on top of the elements arranged on the moulding surface, and the vacuum bag may be sealed against the blade mould. Then, the blade mould cavity within the sealed vacuum bag may be infused with resin. Optionally, the step of resin infusion is followed by curing to obtain the finished blade shell member.
The method for providing a blade shell member may be for providing a suction side shell member or a pressure side shell member. It is to be understood that the same method may be used for providing a suction side shell member as well as a pressure side shell member. The only difference between providing the pressure side shell member and the suction side shell member would be the shape of the blade mould.
In a third aspect, the present disclosure relates to a method of manufacturing a wind turbine blade, comprising the steps of manufacturing a pressure side shell half and a suction side shell half over substantially the entire length of the wind turbine blade in accordance with the second aspect of the present disclosure and subsequently closing and joining the shell halves for obtaining a closed shell.
In a fourth aspect, the present disclosure relates to a blade shell member for a wind turbine blade obtainable by the method for manufacturing a blade shell member according to the second aspect of the present disclosure.
In a fifth aspect, the present disclosure relates to a wind turbine blade obtainable by the method for manufacturing a wind turbine blade according to the third aspect of the present disclosure.
It will be understood that any of the above-described features may be combined in any embodiment of the invention. In particular, embodiments described with regard to the method of manufacturing a blade shell member may also apply to the method of manufacturing a wind turbine blade or a wind turbine and vice versa. Furthermore, embodiments described with regard to the pre-impregnated fibre sheet may also be applied to the method of manufacturing a blade shell member or wind turbine blade.
The invention is explained in detail below with reference to embodiments shown in the drawings, which shall not be construed as limitations.
and
The airfoil region 3400 (also called the profiled region) has an ideal or almost ideal blade shape with respect to generating lift, whereas the root region 3000 due to structural considerations has a substantially circular or elliptical cross-section, which for instance makes it easier and safer to mount the blade 1000 to the hub. The diameter (or the chord) of the root region 3000 may be constant along the entire root region 3000. The transition region 3200 has a transitional profile gradually changing from the circular or elliptical shape of the root region 3000 to the airfoil profile of the airfoil region 3400. The chord length of the transition region 3200 typically increases with increasing distance r from the hub. The airfoil region 3400 has an airfoil profile with a chord extending between the leading edge 1800 and the trailing edge 2000 of the blade 1000. The width of the chord decreases with increasing distance r from the hub.
A shoulder 4000 of the blade 1000 is defined as the position where the blade 100 has its largest chord length. The shoulder 4000 is typically provided at the boundary between the transition region 3200 and the airfoil region 3400.
It should be noted that the chords of different sections of the blade normally do not lie in a common plane since the blade may be twisted and/or curved (i.e. pre-bent), thus providing the chord plane with a correspondingly twisted and/or curved course, this being most often the case in order to compensate for the local velocity of the blade being dependent on the radius from the hub.
In
The pre-manufactured spar cap 100 is preferably infused with vinyl ester resin or epoxy ester resin to maintain the pultruded carbon elements 110 in the stacked array. The pultruded carbon elements 110 are preferably elongated planks with a rectangular cross-section and made from carbon fibres in a cured resin. Alternatively, they may be hybrid pultrusion elements comprising a second type of reinforcement fibres, such as glass fibres. The interlayers 130 comprise fibre material, such as glass fibres, carbon fibres or polymeric fibres etc. for promoting resin flow between the pultruded carbon planks.
The sling 91 is an example of an element for lifting the spar cap 100 from the preparation table 90 to the blade mould 70. As can be seen, the sling 91 is arranged around the spar cap 100 and thus contacts the lower surface 102 of the spar cap 100, as well as the first and second side surfaces 103, 104 of the spar cap 100. This means that if a primer layer is applied to the lower surface 102 and/or side surfaces 103, 104 of the spar cap, the lifting of the spar cap from the preparation table 90 to the blade mould 70 may damage the applied primer layers. In reality, the pre-manufactured spar cap 100 is much longer than illustrated in
The blade mould 70 comprises a moulding surface 71 whereon the different materials for the blade shell member can be arranged. Furthermore, the blade mould 70 comprises a moulding cavity 72. The moulding cavity 72 is the space between the moulding surface 71 and a plane between which the different materials for the blade shell member may be arranged. The cavity 72 is illustrated in
The fibres 27, 28 are maintained relative to each other by a plurality of stitching rows 29 arranged along a first stitch direction between the first and second fibre directions. The stitching rows are illustrated by dotted lines extending along the longitudinal direction 25 of the pre-impregnated fibre sheet 20. In
Furthermore, the side surfaces and/or end surfaces of the spar cap may also be covered by a pre-impregnated fibre sheet or a primer layer.
It should be emphasised that the figures. are schematic only and that in particular the thickness of the different elements in
The pre-impregnated fibre sheet 20 may be rolled up as illustrated in
For a first pre-impregnated fibre sheet 20a configured to be rolled out on a spar cap region 73 in the blade mould 70, the pre-impregnated fibre sheet 20a is preferably rolled up as shown in
For a second pre-impregnated fibre sheet 20b configured to be rolled out on the upper surface 101 of a spar cap 100, the pre-impregnated fibre sheet 20b is preferably rolled up as shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 21159147.4 | Feb 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/054638 | 2/24/2022 | WO |
