Wind turbine blade
By integrating glass fiber layer reinforcement elements between the reinforcing structures of wind turbine blades, the complexity and cost of existing designs are solved, achieving lightweight and efficient load support and simplifying the repair process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SIEMENS GAMESA RENEWABLE ENERGY INNOVATION &TECH SL
- Filing Date
- 2020-09-11
- Publication Date
- 2026-07-10
AI Technical Summary
Existing wind turbine blade designs are complex and expensive, and a design that can adequately support the load without being too complex and expensive is needed.
Integrating a reinforcing element between the first and second reinforcing structures of a wind turbine blade, the reinforcing element consisting of several layers of glass fiber infused with resin simplifies the manufacturing process and reduces the use of carbon fiber.
It reduces the weight and cost of the blades while improving mechanical performance and ease of repair, especially in the joint area, enhancing the overall stiffness and load-bearing capacity of the blades.
Smart Images
Figure CN114630957B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a wind turbine blade having a generally hollow blade body comprising upper and lower half-shells and first and second elongated webs, each extending along the longitudinal direction of the blade and disposed between and connected to the upper and lower half-shells, wherein each web includes upper and lower flanges connecting the respective web to the respective half-shell, and wherein the first and second webs are supported relative to the respective half-shells via respective first and second reinforcing structures disposed between outer and inner layers of the upper and lower half-shells and extending along the longitudinal direction of the blade, wherein each of the first and second reinforcing structures includes at least one stacked member composed of a plurality of pultruded composite strips comprising carbon fibers, wherein the strips are fixed in resin. Background Technology
[0002] As is well known, wind turbine blades are part of a wind turbine used to generate electrical power. A wind turbine typically consists of three blades attached to a hub, which is connected to a generator housed in a nacelle. These blades interact with the passing wind, causing the hub to rotate, ultimately driving the generator.
[0003] Turbine blades typically comprise a hollow blade body with an upper half-shell and a lower half-shell, which are usually manufactured separately and attached to each other. Within this hollow blade body are first and second elongated webs that connect and support the two half-shells, while also transmitting loads acting on the respective shells due to aerodynamics and the circular motion of the blade during rotation. These loads include pressure and suction loads on the upper and lower half-shells, as well as compressive and tensile loads.
[0004] For example, a wind turbine blade with this common configuration is disclosed in EP 2 791 500 B1.
[0005] To support the half-shell and to transfer the corresponding load, each elongated web extends longitudinally and is connected to the corresponding half-shell via flanges disposed on the respective web sides, the flanges being attached to the inner layers of the upper and lower half-shells by adhesive. To transfer the load or, consequently, to support the corresponding shell, each web is supported relative to the corresponding half-shell via corresponding first and second reinforcing structures. Such reinforcing structures are commonly referred to as spar caps. Like the corresponding webs and their flanges, these reinforcing structures or spar caps also extend longitudinally along the blade. As disclosed, for example, in EP 2 791 500 B1, these reinforcing structures are made from a stack comprising separate carbon fiber pultrusion strips arranged on top of each other and fixed in a resin matrix. During the manufacture of such pultrusion strips, carbon fibers are drawn through a supply of liquid resin, which is then heated and cured, ultimately forming the respective pultrusion strip. These pultruded carbon fiber strips exhibit excellent mechanical properties in bearing and distributing loads, and also absorb the high bending moments generated during blade rotation.
[0006] In known wind turbine blade designs, such as those disclosed in EP 2 791 500 B1, the blade includes first and second webs that extend almost entirely along the length of the blade and are arranged in the central body region, i.e., in the region where the upper and lower half-shells, viewed in a teardrop cross-section, are significantly apart. A third web may also be provided, arranged near the trailing edge of the blade. This third web extends only along a portion of the trailing edge, in which the trailing edge typically has a specific edge design and is subjected to specific loads, which are borne or distributed accordingly by this web.
[0007] All webs comprise elongated web bodies with flanges disposed at the ends of the web bodies. Each web is supported by two reinforcing structures, namely spar caps, such that a total of six spar caps are arranged in two shells to support the three webs. If only the first and second webs are provided, four spar caps need to be integrated; if three webs are provided, six spar caps need to be integrated. The spar caps, made of carbon fiber strips, are prefabricated and arranged in the shell mold for their integration. Due to the need to integrate two or three webs and four or six spar caps, the total mass of this known turbine blade is high, but the mass of the spar caps themselves is reduced due to the use of carbon fiber pultruded stacks, which, on the other hand, need to be manufactured outside the shell and are expensive.
[0008] Therefore, there is a need for an improved wind turbine blade design that allows for proper load support and has a less complex and expensive design. Summary of the Invention
[0009] To address this problem, the wind turbine blades mentioned above are characterized in that at least one reinforcing element is arranged between the first and second reinforcing structures, the reinforcing element extending along the first and second reinforcing structures for at least a portion of their length, the reinforcing element comprising at least one stacked member consisting of several layers of glass fiber infused with resin.
[0010] The wind turbine of the present invention is characterized by a specific layout or design of support structures integrated in the upper and lower semi-shells for supporting the first and second webs, which are arranged in portions of two shells of a hollow body that are significantly spaced apart from each other. As in the prior art, both webs are supported by separate first and second reinforcing structures integrated between the outer and inner layers of the shell. Similar to known blade designs, these reinforcing structures are made of a plurality of pultruded composite strips comprising carbon fibers, wherein these strips are embedded in resin.
[0011] The turbine blades of the present invention are characterized not only by the use of first and second reinforcing structures based on carbon strips, but also by the integration of a specific reinforcing element between the first and second reinforcing structures. Furthermore, this reinforcing element is also integrated between the upper and lower layers of a respective half-shell. At least one reinforcing element is provided, extending over at least a portion of the length of the first and second reinforcing structures. This reinforcing element comprises at least one stacked member consisting of several layers of glass fiber infused with resin, thus the reinforcing element is also embedded in the resin, in which the first and second reinforcing structures based on carbon strip fibers are also embedded.
[0012] Therefore, instead of using protruded carbon fiber strips or corresponding prefabricated carbon strip stacks to construct the reinforcing element, which would be expensive and difficult to repair, or consequently prevent the repair of adjacent areas, such as adhesive areas, when needed, the reinforcing element is not used. Instead, at least one simple glass fiber layer composite stack is used, which can be easily constructed directly into the corresponding shell used to produce the half-shell by simply arranging the corresponding glass fiber layer used to construct the at least one stack together with other components required for producing the half-shell. Since the half-shell, which includes several fiber layers to be infused with resin for constructing the corresponding upper and lower shell layers, is ultimately infused with resin, the glass fiber layer stack is also infused with resin in this single infusion step. Thus, the reinforcing element is infused and thus constructed simultaneously while the rest of the half-shell is also infused and constructed.
[0013] Since the reinforcing element, which is attached adjacent to the inner layer of the corresponding shell when viewed along the periphery of the blade, is made of a glass fiber layer embedded in a resin matrix, another advantage of this arrangement is the simplification of the possibility of joint repair, where the web or corresponding flange is attached to the inner layer, because these glass fiber reinforcement structures can be drilled through from the outside of the blade and adhesive injected through the glass laminate, which is impossible when using carbon fiber pultruded reinforcement structures for the reinforcement structure, since they cannot be drilled.
[0014] Therefore, the use of the glass fiber-based reinforcing element of the present invention exhibits several advantages. First, it is simple in design and easy to manufacture, and can be achieved in conjunction with the production of the corresponding shell. Second, the weight of expensive carbon fiber-based reinforcement measures is greatly reduced because only the first and second reinforcing structures include carbon fibers and can be precisely placed only in the shell areas where high loads occur and require treatment. Considering the load or corresponding load distribution, small carbon reinforcing structures can be positioned optimally within the profile of the corresponding shell, as they exhibit enhanced mechanical properties, thereby engaging the reinforcing elements directly connected through the resin matrix. They are particularly capable of reinforcing the flapping bending of the blade. They can be precisely shaped as needed, and therefore their cross-sections can be very thin, because the reinforcing elements placed between them also contribute to the overall stiffness of the blade. The reinforcing element does not include any carbon fiber strips, thus allowing for a reduction in the amount of carbon-based material required, which would be significantly higher when only two reinforcing structures are used to reinforce the blade. The reinforcing element is primarily designed to reinforce the blade against flapping bending. And third, it provides the possibility of repairing these areas, especially in the joint area, because the glass fiber-based reinforcing element can be drilled.
[0015] In summary, the present invention proposes a single reinforcing device comprising first and second reinforcing structures directly adjacent to the web, and a reinforcing device disposed between the two reinforcing structures, wherein the entire reinforcing device is injected or embedded in resin or a corresponding resin matrix. Therefore, this reinforcing device can be considered as a single spar cap supporting two webs.
[0016] The first and second reinforcing structures preferably comprise glass and / or carbon fiber layers arranged between each pair of strips, these layers being infused with resin. These intermediate glass or carbon fiber layers or fabrics allow resin infusion between adjacent pultruded strips, after which the pultruded strips are securely attached to each other following resin curing. Such reinforcing structures can be produced as prefabricated elements and inserted into corresponding shell molds, in which shells are produced and embedded in a resin matrix when the shells are infused with resin. Alternatively, these reinforcing structures can also be constructed directly in the corresponding shell molds, just like reinforcing elements, simply by arranging individual strips and intermediate fiber layers or fiber fabrics in the shell mold and providing resin infusion along with the overall shell infusion. This allows the reinforcing structures to be constructed directly in the shell mold, and thus, the entire reinforcing device, including the reinforcing structures and reinforcing elements together, can be constructed in a single resin infusion step along with the overall infusion of the associated shell components.
[0017] Preferably, the glass and / or fiber layer sandwiched between two adjacent carbon pultruded strips is a biaxial layer. The biaxial fiber layer or fabric comprises fibers arranged at an angle of 0°, while other fibers are arranged at angles of, for example, ±45°. Such a biaxial layer is advantageous because it allows for the bearing of loads in different directions or correspondingly different types, such as flapwise or edgewise bending loads from the blades.
[0018] In another preferred embodiment of the invention, the first and second reinforcing structures and the reinforcing elements are mechanically connected via at least one glass or carbon fiber layer extending from the first reinforcing structure through the reinforcing element to the second reinforcing structure. The reinforcing structures and reinforcing elements are not only embedded in a common resin matrix but are also mechanically connected by at least one glass or carbon fiber layer extending through all these elements or corresponding portions of the reinforcing device. This common fiber layer serves to enhance the mechanical stability and stiffness of the arrangement structure and allows for even better load support and load distribution.
[0019] Preferably, at least one of the glass fiber layers of the reinforcing element extends into both stacks of the first and second reinforcing structures. Thus, mechanical connection is provided by at least one glass fiber layer, which is therefore an integral part of the reinforcing element stack. This glass fiber layer extends laterally into the carbon strip stacks of the reinforcing structures, and then the reinforcing structure or corresponding stack includes this extended reinforcing element layer as an integral layer of the stack. Therefore, in this embodiment, at least one glass fiber layer passes through the reinforcing element from one reinforcing structure and extends into the other reinforcing structure.
[0020] In an alternative, at least one carbon fiber layer sandwiched within the carbon strip-based stack of reinforcing structures may also extend through the reinforcing element and into another reinforcing structure. This embodiment is relevant when the carbon strip stack includes carbon fiber layers sandwiched in the middle and infused with resin. In this case, the reinforcing element is almost entirely composed of glass fiber layers, with only one or a few carbon fiber layers sandwiched in the middle.
[0021] Even when only one layer (glass or carbon fiber layer) extends through the two reinforcing structures and stiffening elements, achieving an improved mechanical layout, it is preferable that all the glass or carbon fiber layers of one reinforcing structure extend through the stiffening element and into the other reinforcing structure. Therefore, there are several mechanical connection planes connecting the reinforcing structures and stiffening elements, which further enhances the mechanical properties of the reinforcing device.
[0022] In the first inventive alternative, only one reinforcing element is provided, which extends over at least 70%, preferably at least 80%, and especially over the entire length of the first and second reinforcing structures. Thus, the two reinforcing structures are mechanically coupled by only one reinforcing element, which preferably extends over most of the length of the reinforcing structure, preferably over their entire length, such that the entire reinforcing device, which may also be called a hybrid reinforcing device or a hybrid spar cap, extends over almost the entire blade length in this particular arrangement.
[0023] In another alternative, two or more reinforcing elements can be provided, each extending only a portion of the length of the first and second reinforcing structures. In this embodiment, two or more separate and shorter reinforcing elements are provided, following each other longitudinally but spaced apart, such that gaps exist between the reinforcing elements when viewed in the longitudinal blade direction. These gaps can be filled, for example, with resin or a lightweight but rigid core element, made of, for example, wood or polymer, which is also embedded in the resin matrix of the entire reinforcing device. This embodiment allows for even greater reduction in the amount of carbon material used, and thus further reduces the overall cost.
[0024] In a preferred embodiment, the stack of reinforcing elements comprises biaxial and uniaxial glass fiber layers. As already mentioned, the biaxial fiber layer comprises fibers arranged at a 0° angle and other fibers arranged at, for example, ±45° angles. Alternatively, the uniaxial fiber layer comprises only parallel fibers that extend along the longitudinal blade direction, just like the 0° fibers of the biaxial layer. The biaxial layer allows for the bearing of loads in different directions or correspondingly different types, i.e., loads arising from blade flapping and flaring bending, while the uniaxial fibers or layers particularly enhance the stiffness against flapping bending. These different layer types can be arranged in an alternating manner, with a uniaxial layer followed by a biaxial layer, then another uniaxial layer, and so on. However, it is also possible to stack, for example, two or three uniaxial layers, followed by one or two biaxial layers, then three uniaxial layers, and so on. Therefore, specific designs regarding the arrangement of the different layer types are possible.
[0025] In another embodiment, one or more core elements are disposed between the outer and / or inner layers of the respective upper and lower half-shells and the reinforcing element. Such core elements allow for filling the space in the region of the reinforcing element, which in turn allows for a smaller, more compact design with sufficient mechanical properties, and the one or more core elements allow for further weight reduction because they are lighter than a resin matrix with embedded glass fiber layers. Such core elements can have generally rectangular, wedge-shaped, or trapezoidal cross-sections. In particular, the wedge-shaped or trapezoidal form provides that the cross-section of the reinforcing element is not linear, but rather curved or angled in some way.
[0026] Furthermore, the core elements may be disposed adjacent to the first and second reinforcing structures between the outer and inner layers of the respective upper and lower half-shells. These core elements, which are also sandwiched between the outer and inner layers of the respective upper and lower half-shells for further adjusting the mechanical properties of the blades in the region of the reinforcing device also close to the shell integration, are also used.
[0027] Any of the core components mentioned above can be made of materials such as foam, wood, polymers, or composites, and this list is not exhaustive.
[0028] The present invention also relates to a wind turbine comprising a plurality of turbine blades as described above, preferably three turbine blades. Attached Figure Description
[0029] Other objects and features of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings. However, the drawings are merely schematic diagrams designed for illustrative purposes only and do not limit the invention. The drawings show:
[0030] Figure 1 Schematic diagram of a wind turbine.
[0031] Figure 2 The first embodiment intercepted along line II-II Figure 1 A cross-sectional view of the blade.
[0032] Figure 3 : Figure 2 An enlarged view of section III, and
[0033] Figure 4 Cross-sectional view of the blade in the second embodiment. Detailed Implementation
[0034] Figure 1 A schematic diagram of a wind turbine 1 is shown, which includes a tower 2, a nacelle 3 mounted on top of the tower 2, and a rotor 4. The rotor 4 includes three wind turbine blades 5 attached to a hub, which is operatively coupled to a generator arranged in the nacelle 3. The generator is driven by the rotational energy of the rotor 4 to generate electrical power as known.
[0035] Each turbine blade 5 includes a root 7 for attaching the blade 5 to the hub 6 and a tip 8 at the other end. It also includes a leading edge 9 and a trailing edge 10.
[0036] This invention relates to the arrangement of wind turbine blades 5.
[0037] Figure 2 It shows along Figure 1 The diagram shows a schematic cross-sectional view of a turbine blade 5 taken along line II-II. The blade 5 comprises a hollow body 11, which is made of an upper half-shell 12 and a lower half-shell 13, which are fixed to each other by an adhesive 14 and enclose a hollow space 15. A first web 16 and a second web 17 are arranged in this space 15. The two webs 16 and 17 are arranged in regions of considerable distance between the upper half 12 and the lower half 13, where the blade has a large thickness. The two webs 16 and 17 extend, for example, almost parallel, and extend almost the entire length of the blade 5, thus beginning adjacent to the root 7 and ending adjacent to the tip 8.
[0038] Both the first and second webs 16 and 17 are used to support the blade housings 12 and 13, and to bear and distribute the corresponding loads placed on the blade 5, which are caused by aerodynamic reasons due to the rotation of the rotor 4 and mechanical reasons due to the weight of the blade 5 itself.
[0039] The first web 16 includes a web body 18 and two flanges 19 integrally attached to the web body 18 at its ends. The same H-shaped design is also implemented in the second web 17, which includes a web body 20 and two end flanges 21 integrally attached to the web body 20.
[0040] Through these flanges 19, 21, the two webs 16, 17 are attached to the inner side 22 of the inner layer 23 by means of adhesives 24, 25, see also Figure 3 .like Figure 3 As shown, the inner layer 23 is part of the corresponding half-shells 12, 13. Figure 3 Only a portion of the upper half-shell 12 is shown, i.e. Figure 2 Section III. It should be noted that the same arrangement is also given at the lower half-shell 13. When the inner layer 23 forms the internal portion of the corresponding shells 12, 13, the outer layer 26 forms the external portion of the corresponding half-shells 12, 13. This design will be about Figure 3 To elaborate further.
[0041] Since the two webs 16, 17 are attached to the inner layer 23 of the shells 12, 13 by adhesives 24, 25, they need to be firmly supported by the corresponding shells 12, 13. To achieve this support in each shell 12, 13, a first reinforcing structure 27 for supporting the first web 16 and a second reinforcing structure 28 for supporting the second web 17 are arranged or integrated accordingly and sandwiched between the inner layer 23 and the outer layer 26. These reinforcing structures 27, 28 are made of corresponding stacks 29, 30, which are made of several pultruded composite strips comprising carbon fibers, wherein these strips are fixed in resin. Figure 3 This setup will be discussed in more detail.
[0042] Between the two reinforcing structures 29 and 30 arranged in the two shells 12 and 13, a reinforcing element 31 is arranged, comprising a plurality of glass fiber layers or fabrics 32 which are also embedded in resin, and preferably in resin in which carbon strip-based stacks 29 and 30 are also embedded. Overall, the combination of the two reinforcing structures 27 and 28 and the reinforcing element 31 forms a single hybrid reinforcing device or hybrid spar cap, which is a very rigid element extending along the longitudinal direction of the blade and supporting the two webs 16 and 17, due to the embedding of the corresponding stacks 29 and 30 and the stacks 32 including carbon fiber pultruded strips in the resin.
[0043] As from Figure 2 As can be seen, reinforcing structures 27 and 28 are arranged in the blade regions where higher loads occur. The blade shell is further strengthened by inserting a glass fiber-based reinforcing element 31 between the reinforcing structures 27 and 28, resulting in a very rigid blade region and design that can withstand and distribute the high loads generated during wind turbine operation.
[0044] The carbon fiber strip-based reinforcing structures 27 and 28 primarily support the webs 16 and 17 and reinforce the blades to prevent, in particular, edgewise bending. The reinforcing device positioned between the reinforcing structures 27 and 28 provides corresponding reinforcement to the blades, especially to prevent flapwise bending, and also provides further reinforcement to the reinforcing structures 27 and 28, as they are firmly attached to the reinforcing element 31 via a common resin matrix. Therefore, the blade 5 of the present invention comprises carbon fiber-based reinforcing structures 27 and 28, customized according to the load requirements and arranged in an optimal position relative to the load profile, while the reinforcing element 31 reinforces the intermediate region and improves the mechanical properties of the overall hybrid reinforcement assembly or corresponding sparsity cap composed of these two reinforcing structures and the intermediate reinforcing device, while also omitting the carbon fiber pultruded strips, as they are made of glass fiber layers. Thus, in the overall blade design, the amount of carbon pultruded material is reduced to what is necessary to provide the required mechanical properties.
[0045] Figure 3 Shown in cross section Figure 2 An enlarged schematic diagram of section III is shown. It partially illustrates two webs 16, 17. Preferably, the two webs, having the same or similar arrangement, include cores 43, 44, made, for example, of balsa wood or foam, extending almost the entire length of the corresponding web bodies 18, 20. These cores are enclosed in glass fiber layers 45, 46 infused with resin 47, 48. The corresponding flanges 19, 21 are integral with the corresponding web bodies 18, 20. The flanges also include several glass fiber layers 49, 50, which are also injected or embedded in the resin 47, 48. Although only one corresponding glass fiber layer 45, 46 and 49, 50 are shown, several of these layers are configured to construct the corresponding large and mechanically rigid outer shell. In particular, the layers 49, 50 that construct the central portion of the corresponding flanges 19, 21 include biaxial and uniaxial glass fiber layers, all of which are injected or embedded in the corresponding resin 47, 48. In addition, the corresponding layers 45 and 46 at the injected web body 18 and 20 may also include uniaxial and biaxial glass fiber layers, just as in the flanges 19 and 21, which can be stacked in any order.
[0046] like Figure 3 It is also shown that the corresponding flanges 19, 21 are securely attached to the inner surface 22 of the inner layer 23 by means of adhesive layers 24, 25. This provides a very robust joint, which is necessary because the corresponding load is transmitted through the joint.
[0047] Figure 3The enlarged view also shows two reinforcing structures 27, 28 and a reinforcing element 31. It is evident that both reinforcing structures 27, 28 and reinforcing element 31 are sandwiched between an inner layer 23 and an outer layer 26, which comprises several fiberglass layers 41, 42 injected or embedded in resin 43 that is injected throughout the respective housings 12, 13, and also embeds a core element 44, for example, made of foam or balsa wood, arranged adjacent to reinforcing structures 27, 28 in the respective housing regions. Needless to say, each layer 23, 26 may certainly include far more than just two fiberglass layers 41, 42, such as… Figure 3 As shown in the schematic diagram.
[0048] like Figure 3 As shown, the two reinforcing structures 27, 28 are arranged in the direct extensions of the respective webs 16, 17. Each structure 27, 28 includes a stack 29, 30, wherein each stack 29, 30 includes a plurality of pultruded composite strips 33, 34, the pultruded composite strips 33, 34 comprising carbon fibers fixed in strip resin. One or more glass or carbon fiber layers 35, 36 are arranged between two adjacent strips 33, 34. These glass or carbon fiber layers 35, 36 are biaxial layers and are used to infuse the respective stacks 29, 30 such that adjacent strips 33, 34 are firmly attached to each other by infusing resin in this region.
[0049] Although only one corresponding glass or carbon fiber layer 35, 36 is shown between two adjacent strips 33, 34, several of these layers may be provided.
[0050] As already mentioned, a reinforcing element 31, comprising a stack 32 consisting of several glass fiber layers 37, is positioned between two reinforcing structures 27, 28. This reinforcing element 31, or its corresponding fiber layers 37, is separated from the adjacent structures 27, 28, or the corresponding carbon-based stacks 29, 30 by only small gaps, resulting in a compact overall design. These layers 37 are also embedded in a resin 38, which is fully embedded in all components of the respective housings 12, 13, particularly the corresponding reinforcing structures 27, 28 and the reinforcing element 31.
[0051] like Figure 3As clearly shown, reinforcing structures 27, 28 and reinforcing element 31 are mechanically interconnected by a plurality of fiber layers extending from reinforcing structure 27 through reinforcing element 31 to reinforcing structure 28. Preferably, both reinforcing structures 27, 28 include glass fiber layers 35, 36, such that the respective layers are common layers to all three elements, namely reinforcing structures 27, 28 and reinforcing element 31. This means that the extended glass fiber layers extending through all components include fiber layers 35, 36 and 37, but are a single layer extending through all three components. This means that the respective extended glass fiber layers form part of the stacks 29, 30 and 31.
[0052] Clearly, all components are injected into the same matrix resin 38. In the production of the respective half-shells, all corresponding components can be inserted into the respective shell molds by inserting the corresponding fiberglass layer 41 for constructing the corresponding inner layer 23, the corresponding core element 39 arranged alongside the reinforcing structures 27, 28, the separate strips 33, 34 with intermediate fiberglass layers 35, 36, and the corresponding shorter fiberglass layer 37 in the area where the reinforcing element 31 should be implemented, followed by the fiberglass layer 42 for constructing the corresponding outer layer 26. After all components are inserted into the corresponding form mold, the form is completely infused with resin for embedding all the inserted components.
[0053] like Figure 3 As shown, in this embodiment, the reinforcing element 31 consists solely of a glass fiber layer 37, especially when the common fiber layer extending through the reinforcing element 31 and the two reinforcing structures 27, 28 are also glass fiber layers. If the stacks 29, 30 include carbon fiber layers, the reinforcing element 31 may include some thin carbon fiber layers. However, the reinforcing element 31 is constructed such that it can be drilled through, as it consists only or primarily of glass fiber layers. This allows a hole to be drilled through the area and reach the corresponding adhesives 24, 25, through which the corresponding webs 16, 17 are attached to the inner layer 23 for repair of the joint if necessary.
[0054] As mentioned, the reinforcement 31 is composed of a glass fiber layer 37. This glass fiber layer stack 32 includes uniaxial and biaxial glass fiber layers, which provide enhanced mechanical properties to withstand the corresponding bending loads caused by oscillating bending and flapping bending.
[0055] Figure 4Another embodiment of the turbine blade 5 is shown, having a similar arrangement to the previously disclosed embodiments. It also includes two half-shells 12, 13, which are fixed to each other by adhesive 14. In the hollow space, two webs 16, 17 are attached to the inner surfaces of the respective half-shells by means of adhesives 24, 25 as described above.
[0056] Furthermore, in each of the semi-shells 12 and 13, two reinforcing structures 27 and 28, including carbon pultruded stacks 29 and 30, are embedded in the resin matrix, and a reinforcing element 31 is arranged between the reinforcing structures 27 and 28. Here, the reinforcing element 31 also includes glass fiber 37, which extends only between the strip stacks 29 and 30, but some of them also... Figure 3 The disclosed extensions are in the corresponding strip stacks 29 and 30.
[0057] and Figure 3 In different embodiments, several core elements 51 are arranged in the regions of corresponding reinforcing elements 31. These core elements 51, which may be made of balsa wood or foam materials, have a wedge shape or a trapezoidal shape, such as... Figure 4 As shown in this example, the number and / or shape of the plurality of core elements 51 may differ in the upper housing 12 and the lower housing 13, but may also be the same.
[0058] These core elements fill the space between the inner and outer layers 23, 26, thereby reducing the amount of glass fiber layer 37 required to construct the respective reinforcing elements 31, and also reducing the amount of resin required to embed them. The geometry of the respective core elements 31 further provides a specific geometry for the reinforcing elements 31 or the respective glass fiber layers 37, because they do not extend in a straight line between the respective reinforcing structures 27, 28, but are instead curved or angled in some way.
[0059] The hybrid reinforcement device or hybrid spar cap, including reinforcing element 31 and reinforcing structures 27, 28, may consist of only one reinforcing element 31, which extends parallel to the reinforcing structures 27, 28 along almost the entire length of the blade 5. In addition to providing only one reinforcing element 31, two or more separate but shorter reinforcing elements 31 may be arranged one after another along the longitudinal direction of the blade 5, with a certain gap between them. This gap may be filled with a core element, such as a foam element, thereby allowing for a further reduction in the mass of carbon fiber used, while providing sufficient stiffness because the several reinforcing elements 31 remain firmly embedded in the entire common matrix of resin 38, and preferably are also mechanically connected to the reinforcing structures 27, 28 by extended glass fiber layers 35, 36 or corresponding 37.
[0060] Although the invention has been described in detail with reference to preferred embodiments, the invention is not limited to the disclosed examples, and other variations can be derived by those skilled in the art from the disclosed examples without departing from the scope of the invention.
Claims
1. A wind turbine blade having a generally hollow blade body (11), the blade body (11) comprising upper and lower half-shells (12, 13) and first and second elongated webs (16, 17), each of the first and second elongated webs (16, 17) extending along the longitudinal direction of the blade (5) and disposed between and connected to the upper and lower half-shells (12, 13), wherein each elongated web (16, 17) comprises a corresponding... Elongated webs (16, 17) are connected to the upper and lower flanges (19, 21) of the respective half-shells (12, 13), and wherein the first and second elongated webs (16, 17) are supported relative to the respective half-shells (12, 13) via respective first and second reinforcing structures (27, 28), which are arranged between the outer and inner layers (23, 26) of the upper and lower half-shells (12, 13) and extend along the longitudinal direction of the blade (5), wherein, The first and second reinforcing structures (27, 28) each include at least one stack (29, 30), the stack (29, 30) of the first and second reinforcing structures (27, 28) being composed of a plurality of pultruded composite strips (33, 34) comprising carbon fibers, wherein the strips (33, 34) are fixed in resin (38), characterized in that at least one reinforcing element (31) is arranged between the first and second reinforcing structures (27, 28) and sandwiched between the outer and inner layers (23, 26) of the upper and lower half-shells (12, 13), the reinforcing element (31) extending along the first and second reinforcing structures (27, 28) for at least a portion of their length, the reinforcing element (31) including at least one stack (32), the stack (32) of the reinforcing element (31) being composed of a plurality of glass fiber layers (47) infused with resin (38).
2. The wind turbine blade according to claim 1, characterized in that, The first and second reinforcing structures include glass and / or carbon fiber layers (35, 36) disposed between each pair of strips (33, 34), the glass and / or carbon fiber layers (35, 36) being infused with the resin (38).
3. The wind turbine blade according to claim 2, characterized in that, The glass and / or carbon fiber layers (35, 36) are biaxial layers.
4. The wind turbine blade according to claim 2, characterized in that, The first and second reinforcing structures (27, 28) and the reinforcing element (31) are mechanically connected by at least one glass and / or carbon fiber layer (35, 36) extending from the first reinforcing structure (27) through the reinforcing element (31) to the second reinforcing structure (28).
5. The wind turbine blade according to claim 2 or 3, characterized in that, At least one of the glass fiber layers (37) of the reinforcing element (31) extends into the two stacked parts (29, 30) of the first and second reinforcing structures (27, 28), or at least one of the glass and / or carbon fiber layers (35, 36) of one of the reinforcing structures (27) of the first and second reinforcing structures extends through the reinforcing element (31) and into the other reinforcing structure (28).
6. The wind turbine blade according to claim 5, characterized in that, All the glass and / or carbon fiber layers (35, 36) of one reinforcing structure (27) extend through the reinforcing element (31) and into another reinforcing structure (28).
7. The wind turbine blade according to any one of claims 1 to 4, characterized in that, Only one reinforcing element (31) is provided, which extends over at least 70% of the first and second reinforcing structures (27, 28).
8. The wind turbine blade according to any one of claims 1 to 4, characterized in that, Only one reinforcing element (31) is provided, which extends over at least 80% of the first and second reinforcing structures (27, 28).
9. The wind turbine blade according to any one of claims 1 to 4, characterized in that, Only one reinforcing element (31) is provided, which extends over the entire length of the first and second reinforcing structures (27, 28).
10. The wind turbine blade according to any one of claims 1 to 4, characterized in that, Two or more reinforcing elements (31) are provided, each of which extends only a portion of the length of the first and second reinforcing structures (27, 28).
11. The wind turbine blade according to any one of claims 1 to 4, characterized in that, The stack (33) of the reinforcing element (31) includes biaxial and uniaxial glass fiber layers (37).
12. The wind turbine blade according to any one of claims 1 to 4, characterized in that, One or more core elements (51) are disposed between the outer and / or inner layers (23, 26) of the respective upper and lower half-shells (12, 13) and the reinforcing element (31).
13. The wind turbine blade according to claim 12, characterized in that, One or each core element (51) has a generally rectangular, wedge-shaped or trapezoidal cross section.
14. The wind turbine blade according to claim 12, characterized in that, The core elements (39, 40) are disposed adjacent to the first and second reinforcing structures (27, 28) between the outer and inner layers (23, 26) of the respective upper and lower half-shells (12, 13).
15. The wind turbine blade according to claim 12, characterized in that, The core elements (39, 40, 51) are made of foam, wood or polymer.
16. A wind turbine comprising a plurality of wind turbine blades (5) according to any one of claims 1 to 15.