Method of manufacturing spar cap, correspondingly manufactured spar cap and wind turbine blade comprising said spar cap
By using weldable resin and resistive components, the problems of material misalignment and injection defects in the production of spar caps were solved, maximizing structural performance and reducing costs, while simplifying the inspection and repair process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SIEMENS GAMESA RENEWABLE ENERGY INNOVATION &TECH SL
- Filing Date
- 2024-09-03
- Publication Date
- 2026-04-24
AI Technical Summary
In the production of spar caps for wind turbine blades, existing technologies have high risks of material misalignment, displacement, and injection defects, leading to increased costs and insufficient structural performance. In particular, the use of carbon fiber materials increases costs and makes defect repair difficult.
By employing a method of weldable resin and resistive elements, multiple structural element layers are arranged side by side with resistive elements placed between them. Energy is used to soften or melt the weldable resin, thereby connecting the structural element layers to form a highly efficient spar cap structure.
It achieves maximum structural performance with minimal material usage, reduces production costs, simplifies inspection and defect repair, and improves automation.
Smart Images
Figure CN121925336A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wind turbine blades, and particularly to a method for producing a spar cap or a portion thereof, a correspondingly produced spar cap or a portion thereof, and a wind turbine blade including such a spar cap. Background Technology
[0002] Wind power is considered one of the cleanest and most environmentally friendly energy sources available today, and wind turbines are gaining increasing attention for utilizing this energy. A modern wind turbine typically consists of a tower, generator, gearbox, nacelle, and one or more rotor blades (also known as wind turbine blades). The rotor blades capture the kinetic energy of the wind and transfer it as rotational energy, allowing the rotor blades to rotate and connect to the gearbox or directly to the generator shaft. The generator then converts the mechanical energy into electrical energy, which can be fed into the power grid.
[0003] As the wind energy industry progresses, the trend is towards producing larger wind turbine blades to reduce the cost of energy (COE) due to increased efficiency and the production of larger rotors. The enormous size of the blades, combined with the need for optimized aerodynamic profiles, necessitates the use of carbon fiber materials in the blade's key structural components, particularly the spar caps.
[0004] Carbon fiber has a unique combination of high modulus, high strength, fatigue resistance and low density. Carbon fiber is usually combined with a polymer resin matrix to form carbon fiber reinforced polymer (CFRP) for use in order to optimize the structure of large blades.
[0005] However, carbon fiber involves higher costs when compared to typical blade reinforcement materials such as glass fiber. One way to minimize the cost impact of carbon materials is to optimize the desired properties by increasing the carbon content and fiber arrangement of CFRP products (typically unidirectional use (UD)), resulting in the use of solid products (such as pultruded parts).
[0006] Pultruded parts are solid strips, typically rectangular in cross-section, formed by pulling carbon filaments through a die under tension; these filaments are impregnated with resin. After being pulled through the die (achieving the final net shape of the cross-section), the resin solidifies through curing or polymerization, forming a solid strip. At a given length, half strips are cut and rolled into coils for transport. Typically, for wind turbine blade designs, these strips range in thickness from 2 mm to 7 mm, width from 50 mm to 200 mm, and length up to or exceeding 100 m.
[0007] If the supplied slats need to be processed to form a spar cap, the spar cap extends almost the entire length of the blade's pressure and suction shells, thus bearing most of the structural load.
[0008] To form the spar cap, several slats are required in both width and thickness (depending on the blade design). Since blade shells are typically manufactured using vacuum-assisted resin infusion molding (VARIM, or simply "infusion"), the entire structure is usually cast into a master mold in a single infusion process. Directly filling the mold with slats to form the spar cap is challenging because the risk of misalignment, displacement, and / or infusion defects in adjacent materials is high (since they are not parts supported under pressure).
[0009] Defects and repairs in carbon spar caps are often extremely difficult in practice, and they are assumed to be costly, even leading to the scrapping of the entire component if they are detected in the final stages.
[0010] To overcome this problem, the spar cap is typically formed from a mold into a prefabricated part through a separate infusion process. This infusion process involves injecting a liquid polymer matrix (usually a two-component thermoset) that wets the space between the spars. The liquid polymer matrix is then heated (externally or through the exothermic reaction heat of a self-induced resin reaction) to solidify the liquid compound into a solid matrix.
[0011] The matrix binds the slat surfaces together to form a uniform spar cap. Since the pultruded slats are rigid parts that do not allow resin to flow under vacuum pressure, an additional layer of fabric (usually carbon fabric) is added between each layer to ensure the necessary penetration for resin flow and complete wetting of all layers.
[0012] The matrix itself and the layers between the slats have stiffness and strength an order of magnitude lower than that of pultruded carbon slats, and they do not add significant structural properties to this part or the final product. Their sole purpose is to form and maintain a sparsity cap prefabricated component with sufficient mechanical properties to transfer interlaminar loads between the slats. Furthermore, they add non-functional weight to the final blade, a critical design factor for the blade and systematically impacting the entire turbine.
[0013] Therefore, further improvements may be needed in the production of spar caps or their components for wind turbine blades, particularly regarding minimizing the amount of material at the slat interface (which does not significantly add to structural performance), thereby minimizing the mass of the slats and maximizing mechanical properties. Additionally, cost reductions and increased automation can be expected through material savings, such as in vacuum materials, waste resin, and vacuum membranes. Furthermore, simplified inspection and defect repair of the spar caps can be anticipated. Summary of the Invention
[0014] This need can be met by the subject matter of the independent claims. Advantageous embodiments of the invention are described by the dependent claims.
[0015] According to an aspect of the invention, a method for producing a spar cap or a portion thereof is provided, the method comprising: providing a plurality of structural elements, each structural element comprising fibers (particularly reinforcing fibers) and a weldable resin; arranging at least two of the plurality of structural elements side-by-side (e.g., adjacent to each other) to form a first structural element layer; arranging at least two of the plurality of structural elements side-by-side (e.g., adjacent to each other) to form a second structural element layer; placing (or arranging) a resistive element between the first structural element layer and the second structural element layer; pressing the first structural element layer and the second structural element layer together; and at least for a portion of the pressing time, energizing the resistive element (i.e., delivering energy to the resistive element) such that the weldable resin softens or melts (thereby connecting the first structural element layer and the second structural element layer).
[0016] According to another aspect of the invention, a spar cap or a portion thereof is provided that can be obtained (or acquired) by the method described herein.
[0017] According to another aspect of the invention, a wind turbine blade is provided, comprising: a first half-shell; a second half-shell; two spar caps, wherein at least one of the two spar caps is a spar cap as described herein; a leading edge; and a trailing edge.
[0018] These aspects of the invention are based on the concept that the structural elements that constitute the spar cap mainly include a weldable resin that can be softened or melted by means of a resistive element that delivers energy and is disposed between two layers of these structural elements, thereby connecting the layers to each other and constructing the spar cap in an efficient manner, wherein there is minimal material between the layers of the structural elements.
[0019] Detailed description The present invention will now be described in detail, along with other features and advantages. However, the invention is not limited to the specific descriptions below, which are for illustrative purposes only.
[0020] It should be noted that features described in conjunction with one exemplary embodiment or aspect may be combined with any other exemplary embodiment or aspect, and in particular features described in conjunction with any exemplary embodiment of the method of producing a spar cap or a portion thereof may be combined with any other exemplary embodiment of the method of producing a spar cap or a portion thereof, and with any exemplary embodiment of the spar cap or a portion thereof, and with any exemplary embodiment of the wind turbine blade, and vice versa, unless otherwise expressly stated.
[0021] When an indefinite or definite article (such as "a", "a kind" or "the") is used to refer to a singular term, the plural form of the term is also included, and vice versa, unless otherwise expressly stated.
[0022] As used in this article, the word "including" not only includes the meaning of "including", "containing" or "containing", but also covers "basically composed of" and "composed of".
[0023] Unless otherwise expressly stated, the expressions “at least in part,” “at least partially,” or “at least (a) part of” as used herein may mean at least 5%, particularly at least 10%, particularly at least 15%, particularly at least 20%, particularly at least 25%, particularly at least 30%, particularly at least 35%, particularly at least 40%, particularly at least 45%, particularly at least 50%, particularly at least 55%, particularly at least 60%, particularly at least 65%, particularly at least 70%, particularly at least 75%, particularly at least 80%, particularly at least 85%, particularly at least 90%, particularly at least 95%, particularly at least 98%, and may also mean 100%.
[0024] In the first aspect, a method for producing a wing spar cap or a portion thereof is provided.
[0025] As used herein, the term "spar cap" specifically refers to a portion of a wind turbine blade that contributes significantly to its mechanical properties and integrity. The spar cap is typically located at the point on the wind turbine blade where it has its maximum thickness.
[0026] The method includes the following steps: providing a plurality of structural elements. The structural elements are not particularly limited, as long as they comprise fibers and weldable resin. Advantageously, the structural elements have a cubic shape with a length (largely) greater than their width and depth. In embodiments, the structural elements have a length of up to 100 m, a width from 50 mm to 200 mm, and a thickness from 2 mm to 7 mm. For example, the length may be 100 m, the width may be 100 mm, and the thickness may be 5 mm. Advantageously, all or at least 90% of the plurality of structural elements may have substantially the same dimensions. However, structural elements of different sizes may also be used depending on design requirements. The structural elements may also be referred to herein as plates, strips, pultruded strips, or pultruded parts.
[0027] Structural elements include fibers, particularly reinforcing fibers. Fibers can be arranged in groups and bundled to form thicker tows or rovings.
[0028] In the embodiments, the fibers include at least one of glass fibers and carbon fibers. While carbon fibers are advantageous due to their high modulus, high strength, fatigue resistance and low density, the inventive techniques described herein are also suitable for glass fibers, which are advantageous in terms of cost.
[0029] Structural elements further include weldable resins. As used herein, the term “weldable resin” may specifically refer to a resin or polymer material that becomes melted or at least softened when heat is applied and exhibits the opposite behavior when cooled, making it suitable for welding or joining two components (e.g., two layers of a structural element) together.
[0030] In embodiments, the weldable resin comprises a thermoplastic polymer or a modified thermosetting polymer. A thermoplastic polymer is a plastic polymer material that becomes soft or moldable at a certain high temperature and solidifies upon cooling. Suitable examples of thermoplastic polymers include poly(methyl methacrylate) (PMMA). In contrast to thermoplastic polymers, thermosetting polymers (which may also be referred to as thermosetting polymers, thermosetting resins, or simply thermosets) are polymers that are irreversibly cured from soft solid or viscous liquid prepolymers or resins. However, modified thermosetting polymers that allow for bond exchange at temperature (e.g., vitrifiers) may also be suitable as weldable resins.
[0031] In the embodiments, one or more, particularly all of the plurality of structural elements, include at least one of the following structures or arrangements 1) to 4): 1) Fibers are embedded in weldable resin. In this configuration, the structural elements may not include thermosetting resin, but are essentially composed of fibers and weldable resin.
[0032] 2) Fibers are embedded in a thermosetting resin, thereby forming the core of the structural element, and the (entire) core of the structural element is coated or covered with a layer of weldable resin. In this arrangement, the fibers are embedded in the thermosetting resin, which can be advantageous in terms of mechanical integrity, and the outer surface of the structural element is made of weldable resin, thereby allowing for diverse connections between structural elements.
[0033] 3) Fibers are embedded in thermosetting resin to form the core of the structural element, and one main surface of the core of the structural element is coated or covered with a layer of weldable resin. Thus, the fibers are again embedded in thermosetting resin, but in this arrangement, only one main surface is provided with weldable resin, thereby enabling specially designed connections of the structural element.
[0034] 4) The fibers are embedded in a thermosetting resin, thereby forming the core of the structural element, and both main surfaces of the core of the structural element are coated or covered with a layer of weldable resin. Thus, the fibers are again embedded in a thermosetting resin, but in this arrangement, both main surfaces are provided with weldable resin, so that the structural element can be used, for example, in a suitable stacked or sandwich configuration.
[0035] In the embodiments, (substantially) all or at least 80%, particularly 90%, of the plurality of structural elements have the same type of arrangement. However, combining different types of arrangements may also be suitable. For example, it may be advantageous to use structural elements having at least one of arrangements 1), 2), and 4) inside the spar cap and structural elements having arrangement 3) on the outer surface of the spar cap (i.e., where one main surface of the structural element does not contain weldable resin). Furthermore, it may also be suitable to use some structural elements that do not contain weldable resin (e.g., structural elements comprising fibers and thermosetting resins). Nevertheless, such non-weldable structural elements can still be coupled with other structural elements that include weldable resin, which is done by the weldable resin of the other structural elements and / or by additional filler materials comprising weldable resin (discussed in further detail below).
[0036] In the embodiments, the thermosetting resin includes at least one resin selected from the group consisting of epoxy resin, vinyl ester resin and polyurethane resin.
[0037] The method further includes the step of arranging at least two of the plurality of structural elements side-by-side (e.g., adjacent to each other) to form a first structural element layer. In embodiments, at least three, particularly at least four, particularly at least five, particularly at least six (e.g., up to 100, particularly up to 50, particularly up to 25, particularly up to 10) of the plurality of structural elements may be arranged side-by-side to form the first structural element layer. While not excluded, the individual structural elements do not need to be adhered to each other or otherwise fixed when arranged side-by-side.
[0038] The method further includes the step of arranging at least two of the plurality of structural elements side-by-side (e.g., adjacent to each other) to form a second structural element layer. In embodiments, at least three, particularly at least four, particularly at least five, particularly at least six (e.g., up to 100, particularly up to 50, particularly up to 25, particularly up to 10) of the plurality of structural elements may be arranged side-by-side to form the second structural element layer. While not excluded, the individual structural elements do not need to be adhered to each other or otherwise fixed when arranged side-by-side.
[0039] The method further includes the step of placing or arranging a resistive element between the first structural element layer and the second structural element layer. As used herein, the term "resistive element" may specifically refer to an element that is electrically or thermally conductive. For example, the resistive element may be electrically conductive and may generate heat by means of the Joule effect. Heat may be generated, for example, by a current or voltage applied to the resistive element.
[0040] In embodiments, the resistive element is arranged along the entire length of the first and second structural element layers. Specifically, the resistive element may be arranged throughout the entire boundary surface or interface of the first and second structural element layers. In some embodiments, it may be advantageous for the resistive element to project laterally (i.e., along the width direction) from the first and second structural element layers. In embodiments, the resistive element comprises carbon fiber, metallic material, or any other (conductive and / or thermally conductive) material.
[0041] In embodiments, the resistive element is in the form of a mesh (e.g., corrosion-resistant wire mesh), woven or non-woven fabric (e.g., carbon fiber fabric).
[0042] In this embodiment, the resistive element is directly disposed between the first structural element layer and the second structural element layer; that is, there are no intervening elements or layers between the resistive element and the first structural element layer, and no intervening elements or layers between the resistive element and the second structural element layer. By taking this measure, the material between the slats can be kept to a minimum.
[0043] In another embodiment, the process may further include, particularly before pressing the first and second structural element layers together, the following steps: placing or arranging a filler material between the resistive material and the first and / or second structural element layers. Specifically, the filler material may include a solderable resin. In some embodiments, it may be advantageous to provide additional solderable resin by means of the filler material, particularly if the structural element used comprises only an amount of solderable resin insufficient to bond the two layers of the structural element, or if some structural elements do not include solderable resin. The filler material may be applied to the resistive element as a coating (where, for example, a mesh or fabric is embedded in the added solderable resin), or as a solid film added to either side (or both sides) of the resistive element.
[0044] The method further includes the step of pressing the first structural element layer and the second structural element layer together. In other words, pressure is applied to the first and second structural element layers, causing them to be compressed or pressed together. For example, a pressure in the range of 1 bar to 3 bar may be applied.
[0045] In one embodiment, the first and second structural element layers are pressed together by means of rollers. Advantageously, the rollers are displaceable relative to the first and second structural element layers along the direction of translational movement, which allows constant pressure to be maintained simultaneously to ensure continuous and uniform welding.
[0046] The method further includes the following steps performed at least for a portion of the pressing time: energizing the resistive element to soften or melt the solderable resin. "Energizing the resistive element" specifically means that energy is generally delivered to the resistive element and should not be limited to the application of electrical energy. For example, electrical energy, thermal energy, or any other suitable energy may be provided to the resistive element. As a result of the energizing step, the first structural element layer and the second structural element layer are joined together.
[0047] In an embodiment, voltage or electrical energy is applied to the resistive element, causing current to flow through it. In other words, a power source can be used to power the resistive element. For this purpose, the resistive element exhibits connection points for electrically connecting the power source to the resistive element. For example, the resistive element protrudes laterally (i.e., along its width) from the first and second structural element layers, thereby allowing electrical contact with the power source.
[0048] In another embodiment, powering the resistive element includes induction welding. For this purpose, one or more inductors may be arranged on top of the first and second structural element layers, and the heating of the resistive layer is caused by an alternating electromagnetic field generated through the inductors(s).
[0049] In another embodiment, powering the resistive element includes ultrasonic welding. For this purpose, one or more ultrasonic welding electrodes may be arranged on top of the first and second structural element layers, and the heating of the resistive layer is caused by high-frequency sound waves generated by the ultrasonic welding electrodes(s).
[0050] In another embodiment, powering the resistive element involves continuous filament welding. For this purpose, heated filaments or metal wires move longitudinally along the first and second structural element layers and heat the weldable resin. The filaments are connected to a power source that generates heat via the Joule effect until the weldable resin melts.
[0051] In another embodiment, powering the resistive element includes hot plate welding. For this purpose, a heating plate is placed between the first and second structural element layers to locally melt the interface weldable resin. The plate can be heated by applying an electric current or by direct heat conduction from the heated surface. The plate is then removed once sufficient time has been given to fully soften the interface and pressure has been applied to the heated area until the material has properly diffused.
[0052] In an embodiment, the method further includes the following steps: arranging at least two of the plurality of structural elements side-by-side (e.g., adjacent to each other) to form a third structural element layer; placing and arranging additional resistive elements between the second and third structural element layers; pressing the second and third structural element layers together; and, at least for a portion of the pressing time, energizing the additional resistive elements to soften or melt the weldable resin (thereby connecting the first, second, and third structural element layers). Similarly, a fourth, fifth, sixth, and so on structural element layers can be connected. Therefore, the height of the spar cap can be increased as needed by adding additional structural element layers.
[0053] In another aspect, the spar cap or a portion thereof is obtainable or acquired by the methods described above. The resistive element used in producing the spar cap (or a portion thereof) remains in the thus acquired spar cap (or a portion thereof) and thus forms part of it. Furthermore, at the end of the spar cap's service life, the resistive element can be reused to separate the layers, for example by applying voltage, thereby facilitating the recycling of the material of the spar cap or a portion thereof.
[0054] In another aspect, a wind turbine blade is provided, comprising a first half-shell, a second half-shell, two spar caps, a leading edge, and a trailing edge. At least one, preferably both, of the spar caps is obtained by the method described above. Attached Figure Description
[0055] Figure 1 A wind turbine is illustrated schematically.
[0056] Figure 2 A wind turbine blade according to an exemplary embodiment is schematically illustrated.
[0057] Figure 3 The illustration shows the following based on Figure 2 An exploded view of a wind turbine blade.
[0058] Figure 4 The illustration schematically depicts a wind turbine blade along... Figure 2 A cross-sectional side view of the intersecting lines IV-IV.
[0059] Figure 5 A schematic plan view of a structural element suitable for use in a method of producing a spar cap or a portion thereof, according to an exemplary embodiment, is shown.
[0060] Figure 6 The diagram schematically illustrates cross-sectional side views of different arrangements of structural elements according to an exemplary embodiment.
[0061] Figure 7 A cross-sectional side view of an intermediate component in a method for producing a spar cap or a portion thereof, according to an exemplary embodiment, is schematically illustrated.
[0062] Figure 8 A cross-sectional side view of a filler material according to an exemplary embodiment is schematically illustrated.
[0063] Figure 9 A schematic plan view of an intermediate component in a method for producing a spar cap or a portion thereof, according to an exemplary embodiment, is shown.
[0064] Figure 10 A cross-sectional side view of an intermediate component in a method for producing a spar cap or a portion thereof, according to an exemplary embodiment, is schematically illustrated.
[0065] Figure 11 A cross-sectional side view of an intermediate component in a method for producing a spar cap or a portion thereof, according to an exemplary embodiment, is schematically illustrated.
[0066] Figure 12 A schematic plan view of process steps in a method for producing a spar cap or a portion thereof according to an exemplary embodiment is shown.
[0067] Figure 13 schematically illustrated Figure 12 A cross-sectional side view of the process steps shown.
[0068] Figure 14 A cross-sectional side view of the final product (which may also serve as an intermediate part) of a method for producing a spar cap or a portion thereof according to an exemplary embodiment is schematically illustrated.
[0069] Figure 15 A schematic cross-sectional side view of the disassembled spar cap according to an exemplary embodiment is shown. Detailed Implementation
[0070] The illustrations in the accompanying drawings are schematic. Similar or identical elements are given the same reference numerals in different drawings.
[0071] Figure 1A wind turbine 1 is schematically illustrated. A wind turbine refers to a device that converts the kinetic energy of wind into rotational energy, which can then be converted back into electrical energy. The wind turbine 1 includes a rotor 2 connected to a generator (not shown) housed within a nacelle 3. The nacelle 3 is positioned at the top of a tower 4 of the wind turbine 1. The rotor 2 includes three wind turbine blades 5. The wind turbine blades 5 are connected to a hub 6 of the wind turbine 1. This rotor 2 can have a diameter ranging from, for example, 30 meters to 160 meters or even larger. The wind turbine blades 5 are subjected to high wind loads. Simultaneously, the wind turbine blades 5 need to be lightweight. For these reasons, the wind turbine blades 5 in modern wind turbines 1 are made of fiber-reinforced composite materials. Often, glass fiber in the form of unidirectional fiber mat is used.
[0072] Figure 2 A wind turbine blade 5 according to an embodiment is schematically illustrated. The wind turbine blade 5 includes: an aerodynamically designed portion 7 shaped to optimally utilize wind energy; and a blade root 8 for connecting the wind turbine blade 5 to a hub 6. The wind turbine blade 5 includes a longitudinal direction 1. The longitudinal direction 1 points from the blade root 8 to the aerodynamically designed portion 7. However, the longitudinal direction 1 can be oriented in reverse. These wind turbine blades 5 are designed to be as lightweight and rigid as possible hollow composite structures to maximize the mechanical energy transferred from wind to the generator. The most commonly used material for manufacturing hollow structures is a composite material in which reinforcing fibers are embedded in a polymer matrix.
[0073] Figure 3 The illustration shows the following based on Figure 2 An exploded view of a wind turbine blade 5. Options for connecting, joining, or welding the hollow structure of the wind turbine blade 5 have so far been limited to either producing the entire structure in a technically complex, specialized injection molding process, or joining sub-sections (most commonly blade half-shells 9, 10) by means of an adhesive bonding process also performed using thermosetting materials. The first half-shell 9 of the wind turbine blade 5 is manufactured and cured in parallel with the second half-shell 10. The two half-shells 9, 10, and additional structural elements 11, 12 (such as shear webs) are then joined together using the adhesive bonding process. The half-shells 9, 10 may have integrated beam caps 13, 14 (… Figure 4 ).
[0074] Figure 4 The illustration schematically depicts a wind turbine blade along... Figure 2A cross-sectional side view of the intersecting line IV-IV. The wind turbine blade 5 has an outer blade shell 15 comprising a first half-shell 9 and a second half-shell 10, which are connected to each other at the leading edge 16 of the wind turbine blade 5. The half-shells 9 and 10 are also connected to each other at the trailing edge 17 of the wind turbine blade 5. The outer blade shell 15 may comprise a composite fibrous material, particularly a glass fiber fabric. The fibrous material is impregnated with a polymer material, particularly a thermosetting resin. The first half-shell 9 constitutes the pressure side of the wind turbine blade 5. The second half-shell 10 constitutes the suction side of the wind turbine blade 5. The first half-shell 9 includes an inner surface 18 and the second half-shell 10 includes an inner surface 19, the two inner surfaces being arranged opposite to and facing each other. The inner space 20 of the wind turbine blade 5 is defined by means of the inner surfaces 18 and 19. The first half-shell 9 includes an outer surface 21 facing away from the inner surface 18. The second half-shell 10 includes an outer surface 22 facing away from the inner surface 19. Structural elements 11 and 12 are located within the inner space 20, extending from the inner surface 18 of the first half-shell 9 to the inner surface 19 of the second half-shell 10. Structural elements 11 and 12, and spar caps 13 and 14, extend along the longitudinal direction 1. Structural elements 11 and 12, and spar caps 13 and 14, preferably comprise fiber composite materials, particularly glass fiber fabric or carbon fiber. Structural elements 11 and 12 are shear-resistant webs.
[0075] Figure 5 A schematic plan view of a structural element 30 suitable for use in a method of producing a spar cap or a portion thereof, according to an exemplary embodiment, is shown. The structural element 30 has a cubic shape and a length L that is significantly greater than its width W and depth T. For example, the length L may be 100 m, the width W may be 100 mm, and the thickness T may be 5 mm. The structural element 30 has two main surfaces, wherein... Figure 5 Only the upper main surface 38a is shown, while the lower main surface is opposite to the upper main surface 38a, and therefore is not shown in the diagram. Figure 5 As shown in the figure, structural element 30 is a fiber-reinforced composite material consisting of unidirectional fibers (such as carbon fibers or glass fibers) and a matrix. The unidirectional fibers are typically embedded in the matrix by means of a pultrusion process, but other processes (such as extrusion, winding, wet molding) may also be used to manufacture structural element 30.
[0076] Figure 6 The diagram schematically illustrates cross-sectional side views of different configurations of structural element 30 according to an exemplary embodiment.
[0077] In configuration 1), fiber 32 is embedded in weldable resin 34. Weldable resin 34 may comprise a thermoplastic polymer or a modified thermosetting polymer, and fiber 32 is a reinforcing fiber, such as glass fiber or carbon fiber. In this configuration, structural element 30 may not include thermosetting resin, but may consist essentially of fiber 32 and weldable resin 34.
[0078] In configuration 2), fibers 32 are embedded in thermosetting resin 36, thereby forming the core 38 of structural element 30, and the (entire) core 38 of structural element 30 is coated or covered with a layer of weldable resin 34. In other words, the core 38 of structural element 30 comprises fibers 32 embedded in thermosetting resin 36. Thermosetting resin 36 may include at least one resin selected from the group consisting of epoxy resin, vinyl ester resin, and polyurethane resin. In this configuration, the fibers 32 are embedded in thermosetting resin 36, which can be advantageous in terms of mechanical integrity, and the outer surface of structural element 30 is made of weldable resin 34, thereby allowing for diverse connections of structural element 30.
[0079] In configuration 3), fiber 32 is embedded in thermosetting resin 36, thereby forming the core 38 of structural element 30, and one main surface 38a of the core 38 of structural element 30 is coated or covered with a layer of weldable resin 34. Thus, fiber 32 is again embedded in thermosetting resin 36, but in this configuration, only one main surface 38a is provided with weldable resin 34, while the other main surface 38b does not contain weldable resin, thereby enabling specially designed connections for structural element 30.
[0080] In configuration 4), the fiber 32 is embedded in the thermosetting resin 36, thereby forming the core 38 of the structural element 30, and the two main surfaces 38a, 38b of the core 38 of the structural element 30 are coated or covered with a layer of solderable resin 34. Thus, the fiber 32 is again embedded in the thermosetting resin 34, but in this configuration, both main surfaces 38a, 38b are provided with solderable resin 34, so that the structural element 30 can be used, for example, appropriately in a stacked or sandwich configuration.
[0081] Figure 7 A cross-sectional side view of an intermediate component in a method for producing a spar cap or a portion thereof, according to an exemplary embodiment, is schematically illustrated.
[0082] In 1), a plurality of structural elements 30 (more specifically, four structural elements 30 in the depicted illustration) are arranged side by side to provide a first structural element layer 40. Furthermore, another plurality of structural elements 30 (more specifically, four structural elements 30 in the depicted illustration) are arranged side by side to provide a second structural element layer 42. The first structural element layer 40 and the second structural element layer 42 are arranged on top of each other, and a resistive element 50 is arranged between the first structural element layer 40 and the second structural element layer 42. The resistive element 50 is in the form of a mesh, woven or non-woven fabric, and preferably comprises carbon fiber, metallic material or any other conductive material characterized by its resistance value.
[0083] In step 2), the first structural element layer 40 and the second structural element layer 42 are pressed together with a controlled amount of surface pressure P to compress the two contact surfaces into the intermediate layer of the resistive element 50. For example, a pressure P in the range of 1 bar to 3 bar can be applied.
[0084] Figure 8 A cross-sectional side view of the filler material according to an exemplary embodiment is schematically illustrated. In some embodiments, for example, if the structural element used comprises only an amount of weldable resin insufficient to connect the two layers of the structural element, or if some structural elements that do not include weldable resin are used, the filler material 54 (typically including weldable resin) may be arranged between the resistive material 50 and the first structural element layer 40 and / or the second structural element layer 42.
[0085] In 1), filler material 54 is applied as a coating to resistive element 50 (where, for example, a mesh or fabric is embedded in an added solderable resin), and the edges or lateral extensions (i.e., lateral protrusions) of resistive element 51 are exposed for electrical connectivity.
[0086] In 2), the filler material 54 is applied as an added solid film to either side (or both sides) of the resistive element 50, i.e., disposed between the resistive element 50 and the first structural element layer 40 and / or the second structural element layer 42.
[0087] Figure 9 A schematic plan view of an intermediate component in a method of producing a spar cap or a portion thereof, according to an exemplary embodiment, is illustrated. A resistive element 50 (e.g., a mesh or fabric of resistive material) is disposed between a first structural element layer 40 and a second structural element layer 42. The resistive element 50 is arranged such that it laterally protrudes from the lateral edges of the first structural element layer 40 and / or the second structural element layer 42. In other words, the width W of the resistive element 50... f The stack width W is greater than the stack width of the first structural element layer 40 and / or the second structural element layer 42. sIf a current or voltage is to be applied to power the resistive element 50, the resulting lateral protrusion of the resistive element 51 is advantageous because the lateral protrusion of the resistive element 51 can be used as an electrical connector.
[0088] Figure 10 A cross-sectional side view of an intermediate component in a method for producing a spar cap or a portion thereof, according to an exemplary embodiment, is schematically illustrated. Figure 10 Furthermore regarding Figure 7 (2) The lateral protrusions of the resistive element 51 are brought into contact with the connectors 64 (which are conductive elements connected to a power source (not shown)) while the stack of the first structural element layer 40 and / or the second structural element layer 42 and the resistive element 50 is held under pressure. These connectors are polarized to allow current to pass through in the lateral direction.
[0089] Figure 11 A cross-sectional side view of an intermediate component in a method for producing a spar cap or a portion thereof, according to an exemplary embodiment, is schematically illustrated. Figure 11 Furthermore regarding Figure 10 A specific amount of power W is applied, thereby inducing heating in the resistive element to a predetermined temperature T due to the Joule effect. Heating causes the solderable resin layer to flow to the point where the contact layer begins to fuse. The current under pressure is maintained for a sufficient time to allow complete molecular diffusion between the bonding surfaces and to solidify the weld line.
[0090] Figure 12 A schematic plan view of process steps in a method for producing a spar cap or a portion thereof according to an exemplary embodiment is shown. Figure 13 schematically illustrated Figure 12 The process steps shown are cross-sectional side views. The bonding step (i.e., pressing together and heating) can be carried out in a continuous manner by applying localized pressure P using rollers or rolls 60, 62, wherein the pre-compacting roll 60, the bonding roll 62, or both move at a speed V simultaneously. If necessary, the rolls 60, 62 may be designed to act as heat sinks. A current W can be applied by conductors 64 (such as conductive wheels) that are in localized contact with the lateral protrusions of the resistive element 51. The entire setup is then translated along the entire length L of the structural element by rotation, thereby maintaining constant P and W at the same time in each segment to ensure continuous and uniform welding.
[0091] Figure 14A schematic cross-sectional side view of the final product (which may also serve as an intermediate part) of a method for producing a spar cap or a portion thereof according to an exemplary embodiment is shown. Once the process is complete and the heat-affected zone has cooled down, the two structural element layers 40, 42 are fully bonded together. Resistive elements (not shown) are embedded in a weldable resin to form a uniform joint. Lateral protrusions of the resistive elements (not shown) can be trimmed. The resulting bonded layer 43 represents the final product, i.e., the spar cap or a portion thereof. However, if a thicker spar cap or a portion thereof is desired, the process can be continued by repeating the process steps. More specifically, a third structural element layer 44 can be provided by arranging the corresponding structural elements side by side, and an additional resistive element 52 can be arranged between the third structural element layer 44 and the bonded layer 43, followed by pressing the layers together and energizing the additional resistive element 52. In fact, this process can be repeated in successive layers to obtain the final thickness of the spar cap as designed. Once the desired thickness of the spar cap is achieved by repeating the process, the result will be a uniform, lightweight spar cap product with minimal addition of non-structural material.
[0092] Figure 15 A schematic cross-sectional side view of the disassembled spar cap according to an exemplary embodiment is illustrated. At the end of the lifespan of the spar cap, the resistive element 52 can be reused to separate each layer by reconnecting it to current.
[0093] Although the present invention has been described in detail through specific embodiments and examples, it should be understood that the present invention is not limited thereto, and various changes and modifications are possible without departing from the scope of the present invention.
Claims
1. A method for producing a wing spar cap (13, 14) or a portion thereof, the method comprising: Multiple structural elements (30) are provided, each structural element including fiber (32) and weldable resin (34); At least two of the plurality of structural elements (30) are arranged side by side to form a first structural element layer (40). At least two of the plurality of structural elements are arranged side by side to form a second structural element layer (42). A resistive element (50) is placed between the first structural element layer (40) and the second structural element layer (42). The first structural element layer (40) and the second structural element layer (42) are pressed together, and the resistive element (50) is powered for at least a portion of the time of the pressing, causing the solderable resin (34) to soften or melt.
2. The method according to claim 1, wherein, The fiber (32) includes at least one of glass fiber and carbon fiber.
3. The method according to claim 1 or claim 2, wherein, One or more of the plurality of structural elements (30), and in particular all of the plurality of structural elements (30), include at least one of the following structures: - The fiber (32) is embedded in the weldable resin (34); - The fiber (32) is embedded in the thermosetting resin (36), thereby forming the core (38) of the structural element, and the entire core (38) of the structural element is coated with a layer of the weldable resin (34). - The fiber (32) is embedded in the thermosetting resin (36), thereby forming the core (38) of the structural element, and a main surface (38a) of the core (38) of the structural element is coated with a layer of the weldable resin (34); - The fiber (32) is embedded in the thermosetting resin (36), thereby forming the core (38) of the structural element, and the two main surfaces (38a, 38b) of the core (38) of the structural element are coated with a layer of the weldable resin (34).
4. The method according to any one of claims 1 to 3, wherein, The weldable resin (34) includes thermoplastic polymers or modified thermosetting polymers.
5. The method according to claim 3 or claim 4, wherein, The thermosetting resin (36) includes at least one resin selected from the group consisting of epoxy resin, vinyl ester resin and polyurethane resin.
6. The method according to any one of claims 1 to 5, wherein, The resistive element (50) includes carbon fiber, metal material or any other conductive material.
7. The method according to any one of claims 1 to 6, wherein, The resistive element (50) is in the form of a mesh, woven or non-woven fabric.
8. The method according to any one of claims 1 to 7, the method further comprising: Before pressing the first structural element layer (40) and the second structural element layer (42) together, a filler material (54) is placed between the resistive element (50) and the first structural element layer (40) and / or the second structural element layer (42).
9. The method according to claim 8, wherein, The filler material (54) includes a weldable resin (34).
10. The method according to any one of claims 1 to 9, wherein, The first structural element layer (40) and the second structural element layer (42) are pressed together by means of rollers (60, 62), which are specifically arranged displaceably relative to the first structural element layer (40) and the second structural element layer (42) along the direction of translational movement.
11. The method according to any one of claims 1 to 10, wherein, Powering the resistive element (50) includes at least one of the following: - Apply voltage to the resistive element (50); - Induction welding; - Ultrasonic welding; - Continuous filament welding; - Hot plate welding.
12. The method according to any one of claims 1 to 11, the method further comprising: At least two of the plurality of structural elements (30) are arranged side by side to form a third structural element layer (44). Another resistive element (52) is placed (arranged) between the second structural element layer (42) and the third structural element layer (44). The second structural element layer (42) and the third structural element layer (44) are pressed together, and the additional resistive element (52) is powered for at least a portion of the time of the pressing, causing the solderable resin (34) to soften or melt.
13. A wing cap (13, 14) or a portion thereof, which is obtainable by the method according to any one of claims 1 to 12.
14. A wind turbine blade (5), comprising: First half-shell (9). Second half-shell (10) Two wing spar caps (13, 14), wherein at least one of the two wing spar caps is the wing spar cap according to claim 13; Leading edge (16); and Trailing edge (17).