Wind turbine blade

Abstract

According to the invention, there is provided a wind turbine blade comprising a blade shell extending longitudinally in a spanwise direction from a root end to a tip end and transversely in a chordwise direction between a leading edge and a trailing edge. The blade shell is formed from opposing first and second half shells, the first and second half shells having a composite laminate structure. Each half shell includes an inner skin on an inner side of the blade shell and an outer skin on an outer side of the blade shell. The blade further comprises a first spar cap located between the inner skin and the outer skin of the first half shell and a second spar cap located between the inner skin and the outer skin of the second half shell. The first spar cap and the second spar cap are opposed to each other. The first spar cap includes a plurality of side-by-side stacks of longitudinally extending strips of reinforcing material, the stacks including at least one web support stack and at least one non-web support stack. The blade also includes a shear web connected between the first spar cap and the second spar cap. The shear web includes a longitudinally extending web panel and first and second mounting flanges extending transversely to the web panel along respective longitudinal edges of the web panel. The first mounting flange adheres to the interior of the first half-shell in the region of the web support stack of the first spar cap, and the second mounting flange adheres to the interior of the second half-shell in the region of the second spar cap. At a first spanwise location along the blade, the number of strips in the web support stack of the first spar cap is different than the number of strips in the non-web support stack of the first spar cap.

Description

Technical Field

[0001] The present invention relates generally to wind turbine blades, and more particularly to a wind turbine blade including a shear web and a pair of spar caps opposed to each other. Background Art

[0002] There's a continuing desire to generate higher levels of electricity from both onshore and offshore wind farms. One approach to achieving this is to provide modern wind turbines with larger blades. Providing larger blades increases the swept area of ​​the wind turbine rotor, allowing the turbine to capture more energy from the wind. However, larger wind turbine blades typically experience increased loads during transportation and in use, partly due to the increased weight of the blades. Therefore, the size of the wind turbine blades often influences the requirements for structural reinforcement of the blades.

[0003] For example, a wind turbine blade may include a shell supported by a longitudinally extending spar structure including a shear web disposed between two opposing spar caps. Longer blades typically include longer spar caps, and such spar caps may also be thicker and / or include more reinforcement material to safely absorb and transfer the increased bending loads experienced by such larger blades in use. However, increasing the amount of reinforcement material in a blade typically increases both the cost and weight of the blade.

[0004] The wind turbine's power rating, or the wind speed level in which the turbine operates, can be another factor influencing the structural reinforcement requirements for wind turbine blades designed for a particular turbine. For example, blades for wind turbines with higher power ratings may require more structural reinforcement than blades designed for wind turbines with lower power ratings. Consequently, structural reinforcement requirements can also vary between wind turbine blades independently of blade length.

[0005] In order to reduce both the cost and weight of wind turbine blades, it is advantageous to minimise the amount of reinforcement material used to manufacture the wind turbine blades where possible, whilst still maintaining the necessary structural reinforcement. It is against this background that the present invention has been developed. Summary of the Invention

[0006] According to a first aspect of the present invention, a wind turbine blade is provided, comprising a blade shell extending longitudinally in a spanwise direction from a root end to a tip end and extending transversely in a chordwise direction between a leading edge and a trailing edge. The blade shell is formed from opposing first and second shell halves, each having a composite laminate structure. Each shell halves includes an inner skin on the inner side of the blade shell and an outer skin on the outer side of the blade shell. The blade further comprises a first spar cap positioned between the inner and outer skins of the first shell half and a second spar cap positioned between the inner and outer skins of the second shell half. The first and second spar caps are opposed to each other. The first spar caps comprise a plurality of side-by-side stacks of longitudinally extending reinforcement strips. The stacks comprise at least one web-supported stack and at least one non-web-supported stack. The blade further comprises a shear web connected between the first and second spar caps. The shear web comprises a longitudinally extending web panel and first and second mounting flanges. The first and second mounting flanges extend transversely to the web panel along respective longitudinal edges of the web panel. The first mounting flange is bonded to an interior of the first shell half in the region of the web support stack of the first spar cap, and the second mounting flange is bonded to an interior of the second shell half in the region of the second spar cap. At a first spanwise location along the blade, a number of straps in the web support stack of the first spar cap is different from a number of straps in the non-web support stack of the first spar cap.

[0007] The spar cap configuration advantageously facilitates customized placement of reinforcement material within a wind turbine blade. For example, the placement of the reinforcement strips can be customized based on the structural reinforcement requirements of one or more specific portions of the blade. In particular, providing the reinforcement material in both the web-supported and non-web-supported stacks facilitates a more customized placement of the strips. The reinforcement material, i.e., the reinforcement strips within each stack, can be individually arranged based on the structural reinforcement requirements of specific spanwise portions of the blade. For example, the placement of the reinforcement material within the first spar cap can be customized in both the spanwise and chordwise directions by individually varying the number and spanwise position of the strips within each individual stack. Thus, the wind turbine blade, and in particular, the spar cap thereof, facilitates greater freedom in the placement of reinforcement material within the blade, enabling the blade to include the necessary amount of reinforcement material where needed, without unnecessarily including additional reinforcement material where it is not needed.

[0008] It will be appreciated that the comparison between the web-braced stack and the non-web-braced stack is made when the wind turbine blade is viewed in transverse cross-section at a spanwise position (ie in a plane perpendicular to the spanwise direction).

[0009] The primary function of a web-support stack is to support the shear web and receive loads transferred from the shear web to the spar caps. For example, the or each stack having at least a portion of the stack within the footprint of the shear web facesheet is a web-support stack. In some examples, the blade may additionally include one or more other stacks within the footprint of the shear web mounting flanges. Such stacks may also receive the majority of the loads transferred from the shear web to the spar caps via the mounting flanges and, therefore, in some examples, may be referred to as web-support stacks.

[0010] In contrast, the primary function of a non-web-supported stack is to provide structural reinforcement to the wind turbine blade to absorb the longitudinal bending loads experienced by the blade shell during use. Any stack outside the footprint of the web mounting flange is a non-web-supported stack. In some examples, the peripheral region of the shear web mounting flange may extend over a peripheral portion of the stack. It should be understood that in such examples, the primary function of the stack cannot be said to be supporting the shear web and receiving the loads transferred from the shear web to the spar caps. Therefore, such a stack may also be referred to as a non-web-supported stack.

[0011] In some examples, the first spar cap may extend over a greater spanwise length than the shear web. Thus, a portion of the spar cap may extend beyond the shear web. It will be appreciated that if such a stack supports a shear web at some point along the length of the stack consistent with the description above, the portion of such a stack extending beyond the shear web may still be referred to as a web-supported stack.

[0012] The reinforcement material may include a fiber reinforced plastic, such as a carbon fiber reinforced plastic (CFRP). In some examples, the strips of reinforcement material may be formed in a pultrusion process and may therefore be referred to as pultrusions. In a preferred example, the strips of reinforcement material may include CFRP pultrusions.

[0013] In some examples, the reinforcement strips may have substantially the same height. That is, the individual reinforcement strips in the or each web support stack may each have the same height as the individual reinforcement strips in the or each non-web support stack. In some preferred examples, all strips in the first spar cap may be substantially identical, except for their respective spanwise lengths. For example, the strips may be pultrusions and, therefore, may have substantially the same composition and substantially the same width and height dimensions. This means that all strips may be manufactured using the same pultrusion process, where the strips can be cut to the desired length in a simple operation.

[0014] In some examples, at a first spanwise location, the height of the web-supported stack of the first spar cap may be different from the height of the non-web-supported stack. The height difference between the web-supported stack and the non-web-supported stack at the first spanwise location may be caused by a different number of straps in each stack at the first spanwise location.

[0015] In some examples, at a first spanwise location, the web support stacks of the first spar cap may include a greater number of straps than the non-web support stacks. Thus, the height of the web support stacks of the first spar cap may be greater than the height of the non-web support stacks. Furthermore, each web support stack of the first spar cap may include a greater amount of reinforcement material than each non-web support stack of the first spar cap. For example, the amount of reinforcement material may be measured by weight.

[0016] In some other examples, at the first spanwise location, the web support stacks of the first spar cap may include fewer straps than the non-web support stacks. Thus, the height of the web support stacks of the first spar cap may be less than the height of the non-web support stacks. Furthermore, each web support stack of the first spar cap may include a smaller amount of reinforcement material than each non-web support stack of the first spar cap.

[0017] In some examples, at a second spanwise location along the blade, the number of straps in the web-supported stack of the first spar cap can be the same as the number of straps in the non-web-supported stack. Here, the number of straps can be tailored to the structural reinforcement requirements of a specific portion of the blade. This configuration allows for the placement of more straps in areas where additional reinforcement is needed, without unnecessarily including straps where they are not needed, thereby helping to minimize the weight and cost of the blade. Specifically, by varying the number of straps in the web-supported and non-web-supported stacks relative to each other at the first and second spanwise locations, the number of straps in each stack can be tailored, rather than across the entire width of the spar cap. This facilitates more fine-tuning of the amount and location of reinforcement material in the blade. At the second spanwise location, the number of straps in the web-supported stack of the first spar cap can be the same as the number of straps in the non-web-supported stack, thereby providing the maximum amount of reinforcement material within a given cross-sectional area of ​​the spar cap.

[0018] In a preferred example, the first spar cap may have a thickness at a first spanwise location that is greater than a thickness at a second spanwise location. In some examples, the first spanwise location may be in the central portion of the blade. The second spanwise location may be between the root end and the central portion of the blade. In some examples, the second spanwise location may be at the root end of the spar cap. Additionally or alternatively, the second spanwise location may be between the tip end and the central portion of the blade. In some examples, the second spanwise location may be at the tip end of the spar cap. It should be understood that, as used herein, the root end of the spar cap refers to the end of the spar cap closest to the root end of the blade, and the tip end of the spar cap refers to the end of the spar cap closest to the tip end of the blade.

[0019] In the central portion of the blade, a shear web is connected between the first and second spar caps. In this central region, the amount of reinforcement in the spar caps can be customized by varying the number of straps in the non-web support stack, without affecting the web height between the first and second spar caps. At a second spanwise location outside the central portion of the blade, the shear web may be absent, so the number of straps in the web support stack can be the same as the number of straps in the non-web support stack.

[0020] In some examples, the central portion may have a spanwise extent of between 10-40% of the total length of the first spar cap, and preferably between 10-30% and more preferably between 10-20% of the total length of the first spar cap. In some examples, the central portion of the blade may be spaced apart from the root end of the blade by at least 0.1L, preferably at least 0.2L, more preferably at least 0.3L, where L represents the total length of the blade.

[0021] In some examples, the first spanwise position may be spaced apart from the root end of the blade in the spanwise direction by at least 0.1L, preferably at least 0.2L, more preferably at least 0.3L, where L represents the total length of the blade.

[0022] In some examples, the first spar cap may have a maximum thickness throughout the central portion of the blade. Furthermore, the thickness of the first spar cap may taper outward from the central portion. For example, the thickness of the first spar cap may taper toward the root end of the blade. Thus, the first spar cap may include a tapered root portion. In some examples, the tapered root portion may include a second spanwise position. Additionally or alternatively, the thickness of the first spar cap may taper toward the tip end of the blade. Thus, the first spar cap may include a tapered tip portion. In some examples, the tapered tip portion may include a second spanwise position.

[0023] In some examples, at the second spanwise location, the first spar cap may have a substantially constant thickness across its full width in the chordwise direction. Conversely, in some examples, at the first spanwise location, the thickness of the first spar cap may vary across its full width in the chordwise direction. In preferred examples, the thickness of the first spar cap may vary across its full width in the chordwise direction throughout the central portion of the blade. In other words, the or each web support stack may have a different height than the or each non-web support stack throughout the central portion of the blade.

[0024] In some examples, the first spar cap may include tapered strips of reinforcement material. For example, the thickness of one or more reinforcement strips in the spar cap may taper toward their tip end. Additionally or alternatively, the thickness of one or more reinforcement strips may taper toward their root end. In preferred examples, the thickness of each reinforcement strip may taper toward its respective root and tip ends. Thus, in examples where the thickness of the first spar cap tapers, the tapered ends of the reinforcement strips may contribute to forming a tapered spar cap, i.e., one that tapers smoothly rather than in a stepped manner. It should be understood that the root end or tip end of a reinforcement strip is used herein to refer to the end of the strip closest to the root end of the blade or the end closest to the tip end of the blade, respectively.

[0025] In some examples, the strips forming the first spar cap may be arranged in multiple layers. Additionally, in some examples, the number of strips in the outermost layer adjacent the outer skin may be greater than the number of strips in the innermost layer.

[0026] The thickness of the spar cap may taper in the spanwise direction, moving towards the root end of the blade and / or towards the tip end of the blade. In other words, the thickness of the spar cap may taper at one or both ends. This taper may be achieved by arranging the strips so that their root and tip ends terminate at different spanwise locations along the blade. For example, the outermost strip in the stack may have the greatest length, and moving towards the innermost layer, the strips may become progressively shorter within the thickness of the spar cap. The or each strip in the innermost layer of the spar cap may have the shortest spanwise length.

[0027] Thus, in preferred examples, the strips in the innermost layer can be shorter than the strips in the outermost layer. In some examples, the strips in the outermost layer can be at least as long as the strips in each of the other layers. In preferred examples, the strips in the outermost layer can be longer than the strips in each of the other layers.

[0028] In some examples, the innermost layer of straps in the first spar cap may consist solely of straps within the web support stack. Alternatively, in some examples, the innermost layer of straps in the first spar cap may consist solely of straps within the non-web support stack.

[0029] In some examples, each layer of the first spar cap may include the same number of straps except for one or more innermost layers, which may include fewer straps. These straps may be only within the web support stack or only within the non-web support stack.

[0030] Each strap in the outermost layer can include an outward-facing surface, i.e., a surface facing the outer skin. Furthermore, each web-supported stack and each non-web-supported stack can include an outward-facing surface defined by a strap in the outermost layer. In a preferred example, the outward-facing surface of a stack can be defined by a single strap. For example, the outermost strap of each stack preferably extends along the total span-wise length of the corresponding stack, thereby defining the total span-wise length of the corresponding stack.

[0031] In some examples, the outermost straps in each stack of the first spar cap may be substantially identical. In a preferred example, the outermost straps in each stack may be substantially flush with the outermost straps in each adjacent stack, such that the outwardly facing surfaces of each stack are substantially flush with each other.

[0032] It will be appreciated that each stack comprises one or more innermost strips of reinforcement material. The or each innermost strip of each stack defines an inward-facing surface of the respective stack. In a preferred example, the inward-facing surface of each stack is defined by a single innermost strip of the respective stack. It will be appreciated that due to the difference in the number of strips in the web-supported and non-web-supported stacks, the innermost strips of the stacks may form different layers of the spar cap. Consequently, the innermost strips of the stacks may not be flush with one another, and the inward-facing surfaces of each stack may not be flush with one another.

[0033] In some examples, the first spar cap may include a filler material configured to smooth the transition between adjacent stacks of different heights. In some examples, the filler material may include ropes of unidirectional fibers. In some other examples, the filler material may include a filler material such as cotton batting or wool. The filler material advantageously prevents the formation of resin-rich regions in portions of the spar cap where there is a height difference between adjacent stacks.

[0034] In some examples, the first spar cap may include: one or more web support stacks defining a chord-wise center of the first spar cap; one or more first non-web support stacks on leading edge sides of the web support stacks; and one or more second non-web support stacks on trailing edge sides of the web support stacks. In some such examples, the non-web support stacks of the first spar cap may define longitudinal edges of the first spar cap.

[0035] In some other examples, the first spar cap may include: one or more first web support stacks supporting the first shear web; one or more second web support stacks supporting the second shear web; and one or more non-web support stacks disposed between the first web support stacks and the second web support stacks. In some such examples, the web support stacks of the first spar cap may define longitudinal edges of the first spar cap.

[0036] In some examples, the first and second mounting flanges of the shear web may be wider in the chordwise direction than the web faceplate. Preferably, the mounting flanges may be significantly wider in the chordwise direction than the web faceplate. This provides stability to the shear web and also provides a relatively large surface area for bonding the shear web to the blade shell.

[0037] In some examples, the first mounting flange and the second mounting flange may each extend transversely to the web panel on a single side of the web panel. For example, the first mounting flange and the second mounting flange may both extend transversely to the web panel on the same side of the web panel, such that the shear web has a substantially C-shaped cross-section. Alternatively, the first mounting flange and the second mounting flange may each extend transversely to the web panel on different sides of the web panel, such that the shear web has a substantially Z-shaped cross-section.

[0038] In a preferred example, the first and second mounting flanges may each extend transversely to the web panel on a first and second side thereof, such that the shear web resembles an I-beam, i.e., the shear web may be substantially I-shaped in cross-section. This may help distribute loads among the mounting flanges and safely transfer loads between the spar caps and the shear web in use. The mounting flanges preferably extend substantially the same chordwise distance from the web panel on the first and second sides thereof, such that the web panel is located in the middle of the shear web when viewed in cross-section.

[0039] In a preferred example, the shear web may be substantially centrally aligned relative to the or each web support stack supporting that particular shear web. In other words, when viewed in cross-section, the shear web face sheet is preferably substantially aligned with the chordwise midpoint of the or each web support stack. This helps maintain uniform load distribution through the mounting flange and across the or each web support stack.

[0040] In some examples, the shear web may be supported by a single web support stack of the first spar cap. In such examples, the strip of reinforcement material preferably has a chord-wise width at least equal to the chord-wise width of the first mounting flange of the shear web. More preferably, in such examples, the strip of reinforcement material may have a chord-wise width greater than the chord-wise width of the first mounting flange.

[0041] In some examples, the cross-sectional profile of the reinforcement material strips can be substantially rectangular. In other words, when the wind turbine blade is viewed in cross-section at a spanwise position (i.e., in a plane perpendicular to the spanwise direction), the reinforcement material strips can be substantially rectangular. This is advantageous for precise alignment and positioning of the strips during manufacture of the wind turbine blade.

[0042] In some examples, the reinforcement material strips may have an aspect ratio of at least 10:1, and preferably at least 20:1. The aspect ratio may be defined as the ratio of the width of the strip in the chord-wise direction to the thickness of the strip. In some preferred examples, the strips may have a width of approximately 100 mm and a thickness of approximately 5 mm, thereby providing an aspect ratio of 20:1, or in some examples, the strip width may be approximately 200 mm, providing an aspect ratio of 40:1. The strips have a substantial length perpendicular to their width and thickness. Preferably, at least the outermost strip of each stack extends the entire length of the spar cap, or at least a substantial portion of the length of the spar cap.

[0043] According to a second aspect of the present invention, a series of wind turbine blades having substantially equal lengths and substantially identical external shapes is provided. Each blade includes a blade shell extending longitudinally in a spanwise direction from a root end to a tip end and extending transversely in a chordwise direction between a leading edge and a trailing edge. The blade shell is formed by opposing first and second shell halves. Each blade further includes a first spar cap associated with the first shell half and a second spar cap associated with the second shell half. The first and second spar caps are opposed to each other. The first spar caps include a plurality of side-by-side stacks of longitudinally extending reinforcement strips, the stacks including at least one web-supported stack and at least one non-web-supported stack. Each blade further includes a shear web connected between the first and second spar caps. The series of wind turbine blades includes: a first blade designed for a first wind turbine operating in a first wind class or having a first power rating; and a second blade designed for a second wind turbine operating in a second wind class or having a second power rating. The second wind class or second power rating is different from the first wind class or first power rating. At a first spanwise position along the blade, the number of straps in the non-web support stack of the first spar cap of the first blade is different from the number of straps in the corresponding non-web support stack of the first spar cap of the second blade.

[0044] The first blade and the second blade in the series have equal lengths and substantially the same external shape. Thus, the first blade and the second blade can be manufactured using the same equipment. For example, the corresponding first shell half of each blade in the series can be manufactured in the same shell mold. Similarly, the corresponding second shell half of each blade in the series can be manufactured in the same mold. Thus, by facilitating the reuse of the same mold to form different wind turbine blades for different turbines operating in different wind classes or having different power ratings, a significant reduction in manufacturing costs is possible. Additionally, using the same molding equipment to form the different blades significantly reduces factory floor space usage in the blade manufacturing facility because fewer molds are required to form the different blades.

[0045] In a particularly preferred example, the first and second blades in a series can be substantially identical, except for the configuration of their respective spar caps. For example, while the first and second blades are of equal length and have substantially the same external shape, i.e., have substantially the same external geometry, in a preferred example, the internal components of the first and second blades (except for the respective spar caps) can also be identical, as described in more detail later. Sharing components between different blades in a series can further reduce manufacturing costs due to economies of scale and reduce the amount of engineering effort involved in designing different components for different blades.

[0046] It should be understood that, as used herein, the term "corresponding" is used to refer to components of each blade in the series that perform the same function as one another and are located at equivalent locations within each blade in the series. For example, a non-web support stack of a first spar cap of a first blade and a corresponding non-web support stack of a first spar cap of a second blade may be located at substantially the same location within the respective first and second blades and within the respective first spar caps. It should be understood that this is provided by way of example only, to illustrate one example of many possible "corresponding" components for each blade in the series.

[0047] In some examples, the first blade in the series of wind turbine blades may be a blade as previously described according to examples of the first aspect of the invention. Additionally or alternatively, the second blade in the series of wind turbine blades may be a blade as previously described according to examples of the first aspect of the invention.

[0048] In some examples, the non-web support stack of the first spar cap of the first blade may include a different amount of reinforcement material than the corresponding non-web support stack of the first spar cap of the second blade. In other words, the non-web support stack of the first blade may include a first amount of reinforcement material, and the corresponding non-web support stack of the second blade may include a second amount of reinforcement material that is different from the first amount.

[0049] For example, the non-web support stack of the first spar cap of the first blade may include a first mass of reinforcement material, and the corresponding non-web support stack of the first spar cap of the second blade may include a second mass of reinforcement material different from the first mass. Thus, the non-web support stack of the first spar cap of the first blade may have more or less weight of reinforcement material than the corresponding non-web support stack of the first spar cap of the second blade.

[0050] The stacks of reinforcement material strips are preferably arranged side by side in the chord-wise direction, ie each stack is preferably adjacent to at least one other stack in the chord-wise direction.

[0051] In some preferred examples, the corresponding first spar caps of the first and second wind turbine blades can have the same width in the chord-wise direction along the length of the spar caps. Advantageously, this can mean that the design does not vary substantially between blades in a series. For example, the blade shell of each blade can include a core panel arranged on each side of the first spar cap. Maintaining the width dimension of the first spar cap between different blades in a series means that the same core panel can be used to manufacture the blade shells of different blades in the series.

[0052] Thus, in some examples, the first spar cap of the first blade can include the same number of side-by-side stacks as the first spar cap of the second blade. Furthermore, the strips in each stack of the first spar caps of the first blade can have substantially the same width and thickness as the strips in each corresponding stack of the first spar cap of the second blade. Thus, the corresponding first spar caps of the first wind turbine blade and the second wind turbine blade can have the same width in the chordwise direction.

[0053] In some examples, the first blade may be designed for a first wind turbine that operates in a higher wind level or has a higher power rating than a second wind turbine that the second blade is designed for. In such an example, at a first spanwise position, a number of straps in a non-web supported stack of a first spar cap of the first blade may be greater than a number of straps in a corresponding non-web supported stack of the first spar cap of the second blade.

[0054] Wind force classes are defined by the International Electrotechnical Commission (IEC) in IEC 61400. For example, a first blade may be designed to operate in wind force class I (high winds), and a second blade may be designed to operate in wind force class III (low winds). In the context of this disclosure, when referring to wind force classes, the term "higher" means a stronger wind force class, i.e., wind force class I is higher than wind force class II.

[0055] The rated power of a wind turbine is defined in IEC 61400 as the maximum continuous electrical power output that the wind turbine is designed to achieve under normal operating conditions and external conditions. Large commercial wind turbines are typically designed for a lifespan of 20 to 30 years, and their rated power output takes this lifespan into account. For example, a first blade may be designed for a wind turbine with a rated power of 6 MW, and a second blade may be designed for a wind turbine with a rated power of 4 MW.

[0056] In some examples, each strip of reinforcement material in the first spar cap of each blade may have the same thickness. Thus, a difference in the number of strips in the corresponding non-web support stacks of the first spar caps of the first and second blades may result in a difference in the height of the stacks.

[0057] In some examples, at the first spanwise position, the height of the or each non-web support stack of the first spar cap of the first blade may be different from the height of the corresponding or each non-web support stack of the first spar cap of the second blade.

[0058] In some examples, at the first spanwise position, the height of the or each non-web support stack of the first spar cap of the first blade may be greater than the height of a corresponding non-web support stack of the first spar cap of the second blade.

[0059] In some examples, at a first spanwise position along the blade, the number of straps in the or each web support stack of the first spar cap of a first or second blade in the series may be different from the number of straps in the or each non-web support stack of the first spar cap of that blade.

[0060] In some examples, the second spar cap of each blade may comprise a plurality of side-by-side stacks of longitudinally extending strips of reinforcement material.The stacks of second spar caps may comprise at least one web-supported stack and at least one non-web-supported stack.

[0061] In some examples, the shear web of each blade may be connected between one or more web support stacks of first and second opposing spar caps. Along the lengths of the first and second spar caps, the spacing between the web support stacks of the first and second spar caps of the first blade is preferably substantially the same as the spacing between the web support stacks of the first and second spar caps of the second blade.

[0062] In some preferred examples, along at least a portion of the length of the spar caps, the spacing between the non-web support stacks of the first and second spar caps of the first blade may be different than the spacing between the corresponding non-web support stacks of the first and second spar caps of the second blade.

[0063] In some examples, the or each web support stack of the first spar cap of a first blade may be substantially identical to the or each corresponding web support stack of the first spar cap of a second blade. This helps to improve the efficiency of the design, manufacture, and assembly of blades in a series by reducing variations between components of different blades in the series.

[0064] In some examples, the shear web of the first blade may be substantially identical to the shear web of the second blade. For example, the shear web of the first blade may have substantially the same height as the shear web of the second blade. In particularly advantageous examples, the use of substantially identical shear webs in the first and second blades may be facilitated at least in part by the aforementioned spacing between the web support stacks of the first and second spar caps of the first blade being substantially identical to the spacing between the web support stacks of the first and second spar caps of the second blade.

[0065] A family of blades, each including the same shear web, is particularly advantageous for reducing the cost of designing and manufacturing the different blades in the family. Often, a shear web may be specific to a particular blade for use in a particular wind class or for a turbine having a particular power rating. Consequently, manufacturing blades for different turbines typically requires additional engineering and tooling to manufacture the different shear webs. By using the same shear web in different blades in a family of wind turbine blades, the cost of designing and machining the shear webs in the family is limited to a single shear web design.

[0066] At a second spanwise position along the blade, the number of straps in the or each non-web support stack of the first spar cap of the first blade may be the same as the number of straps in the or each corresponding non-web support stack of the first spar cap of the second blade.

[0067] In some examples, the first spanwise location may be in a central portion of the blade and the second spanwise location may be between the root end and the central portion of the blade. Additionally or alternatively, the second spanwise location may be between the tip end and the central portion of the blade.

[0068] In some examples, for each blade in the series, the central portion may have a spanwise extent of between 10-40% of the total length of the first spar cap, and preferably between 10-30% and more preferably between 10-20% of the total length of the first spar cap. Furthermore, in some examples, the central portion of each blade in the series may be spaced from the root end of the blade by at least 0.1L, preferably at least 0.2L, and more preferably at least 0.3L, where L represents the total length of the blade.

[0069] In some examples, the first spanwise position of each blade in the series may be spaced at least 0.1L, preferably at least 0.2L, more preferably at least 0.3L from the root end of the blade in the spanwise direction, where L represents the total length of the blade.

[0070] In some examples, throughout the center section, the height of the or each non-web support stack of the first spar cap of the first blade may be different from the height of the or each non-web support stack of the first spar cap of the second blade.

[0071] In some examples, excluding the center section, the or each non-web support stack of the first spar cap of the first blade may be identical to the non-web support stack of the first spar cap of the second blade.

[0072] In some examples, for both the first blade and the second blade, each stack of the first spar cap may taper from a respective maximum height portion towards both a root end of the stack and a tip end of the stack. In some examples, the maximum height portion of the or each non-web supported stack of the first blade may be offset in the spanwise direction compared to the maximum height portion of the or each non-web supported stack of the second blade.

[0073] In some examples, the first spar cap of each blade in the series may include one or more web support stacks that define a chord-wise center of the first spar cap. Additionally, the first spar cap may include: one or more first non-web support stacks on the leading edge side of the web support stacks; and one or more second non-web support stacks on the trailing edge side of the web support stacks. Thus, the web support stack(s) may be sandwiched between a pair of non-web support stacks in the chord-wise direction. In such examples, the non-web support stacks of the first spar cap of each blade may define a longitudinal edge of the corresponding spar cap.

[0074] In some other examples, the first spar cap of each blade in the series may include: one or more first web support stacks supporting the first shear web; and one or more second web support stacks supporting the second shear web. The first spar cap of each blade may also include one or more non-web support stacks arranged between the first web support stacks and the second web support stacks. In such examples, the web support stacks of the first spar cap of each blade may define longitudinal edges of the first spar cap.

[0075] In some examples, the shear web of each blade in the series may include: a longitudinally extending web panel; and first and second mounting flanges extending transversely to the web panel along respective longitudinal edges of the web panel. The first and second mounting flanges of each shear web are preferably wider in the chordwise direction than the web panel.

[0076] In some examples, for each blade in the series, a first mounting flange of the shear web can be bonded to the inner surface of the first shell half in the region of the web support stack of the first spar cap. Additionally, a second mounting flange of the shear web can be bonded to the inner surface of the second shell half in the region of the second spar cap. For example, the second mounting flange of the shear web can be bonded to the inner surface of the second shell half in the region of the web support stack of the second spar cap.

[0077] For each blade, the first and second mounting flanges of the shear web may extend transversely to the web panel on a first side of the web panel and a second side of the web panel, respectively. Thus, in a preferred example, the shear web of each blade may resemble an I-beam, i.e., the cross-section of the shear web may be substantially I-shaped.

[0078] In a preferred example, the first and second shell halves of each blade in the series may comprise a composite laminate structure. Thus, each shell half may include an inner skin on the inside of the blade shell and an outer skin on the outside of the blade shell. In such an example, the first spar cap of each blade may be located between the inner and outer skins of the first shell half, and the second spar cap of each blade may be located between the inner and outer skins of the second shell half.

[0079] It will be appreciated that the second spar cap of each blade in the series may be substantially similar to the first spar cap. Thus, it will be appreciated that, in some examples, the features described with reference to the first spar cap of each blade may be equally applicable to the second spar cap of each blade. It is noteworthy that the first and second spar caps of a blade may not necessarily be configured in the same manner, i.e., the stacking of strips may be arranged differently and may include different numbers of strips for the first and second spar caps of blades in the series. Furthermore, it will be appreciated that, in some examples, the different spar cap configurations, i.e., different arrangements of strips, described by way of example with reference to the first aspect of the invention may be equally applicable to the spar caps of blades in the series of wind turbine blades of the second aspect of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Examples of the present invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0081] Figure 1 is a schematic exploded view of a wind turbine blade;

[0082] Figure 2 is a schematic plan view of a wind turbine blade;

[0083] Figure 3ais a schematic cross-sectional view of a wind turbine blade taken at a first spanwise location, the cross-sectional view illustrating a first spar cap comprising a plurality of strips of reinforcement material stacked side by side;

[0084] Figure 3b is a schematic cross-sectional view of a wind turbine blade taken at a second spanwise location;

[0085] Figure 4a is a side view of the web support stack of the strips of the first spar cap;

[0086] Figure 4b is a side view of a non-web support stack of strips of a first spar cap;

[0087] Figure 5a and Figure 5b is a schematic cross-sectional view of another example of a wind turbine blade taken at a first spanwise position and a second spanwise position, respectively;

[0088] Figure 6 is a schematic plan view of a series of wind turbine blades of substantially equal length and substantially identical external shape;

[0089] Figure 7a is a schematic cross-sectional view of a first blade in the series taken at a first spanwise position along the first blade;

[0090] Figure 7b is a schematic cross-sectional view of a second blade in the series taken at a first spanwise position along the second blade;

[0091] Figure 7c is a schematic cross-sectional view showing a cross-section taken at a second spanwise position of both the first blade and the second blade;

[0092] Figure 8a is a side view of a non-web support stack of strips of a first spar cap of a first blade;

[0093] Figure 8b is a side view of a non-web support stack of a corresponding strip of a first spar cap of a second blade; and

[0094] Figure 8c is a side view of the web support stack of the straps of the first spar caps of the first and second blades. DETAILED DESCRIPTION

[0095] Figure 1 and Figure 2A wind turbine blade 10 is shown in schematic exploded and plan views. The blade 10 includes a first shell half 12a and a second shell half 12b that are connected together to form a blade shell 14. The blade shell 14 extends longitudinally in a spanwise direction (S) from a root end 16 to a tip end 18 and extends transversely in a chordwise direction (C) between a leading edge 20 and a trailing edge 22. The blade shell 14 preferably defines an aerodynamic profile that is configured to capture energy from wind incident on the blade 10 during use.

[0096] The wind turbine blade 10 also includes a shear web 24 configured to absorb and transfer shear loads experienced by the blade 10 during use. The shear web 24 includes a longitudinally extending web panel 26 and first and second mounting flanges 28a, 28b extending transversely to the web panel 26 along respective longitudinal edges of the web panel 26. In some examples, the first and second mounting flanges 28a, 28b may extend transversely to the web panel 26 on first and second sides of the web panel 26, such that the shear web 24 resembles an I-beam, for example, as shown in FIG. Figure 1 shown.

[0097] As now reference Figure 3a and Figure 3b As described in more detail in the cross-sectional view shown in FIG, the wind turbine blade 10 further includes a first spar cap 30a and a second spar cap 30b. For reference, Figure 3a The first spanwise position A (at Figure 2 A schematic cross-sectional view of the blade 10 taken at (indicated in FIG), and Figure 3b At the second spanwise position B (also Figure 2 A second schematic cross-sectional view of the blade 10 is taken at (indicated in FIG. 2 ).

[0098] The first and second spar caps 30a, 30b are preferably integrated with the first and second half shells 12a, 12b. Consequently, the blade shell 14 can be referred to as a so-called structural shell. The opposing first and second half shells 12a, 12b have a composite laminate structure, and each half shell 12a, 12b thus comprises an inner skin 32 on the inside of the blade shell 14 and an outer skin 34 on the outside of the blade shell 14. The first spar cap 30a is located between the inner skin 32a and the outer skin 34a of the first half shell 12a, and the second spar cap 30b is located between the inner skin 32b and the outer skin 34b of the second half shell 12b.

[0099] Still refer to Figure 3a and Figure 3bThe first spar cap 30a includes a strip 36 of reinforcement material, such as carbon fiber reinforced plastic (CFRP). The strip 36 is preferably substantially rectangular in cross-section. For example, the strip 36 may have an aspect ratio, defined as the ratio of the strip's chord-wise width to its thickness, of at least 10:1, and preferably at least 20:1. For example, the strip 36 may have a chord-wise width of approximately 200 mm and a thickness of approximately 5 mm, resulting in an aspect ratio of 40:1. It should be understood that the schematic illustrations in the accompanying drawings are not to scale, and in particular, the thickness of the strip 36 is exaggerated in the accompanying drawings to more clearly illustrate the strip 36.

[0100] The strips 36 extend longitudinally in the span direction (S) and are arranged in a plurality of side-by-side stacks 38 , 40 . Figure 3a and Figure 3b The example shown shows a first spar cap 30a including a single web support stack 38 and two non-web support stacks 40. However, as will be described in more detail later, in other examples, the stacks 38, 40 may include one or more web support stacks 38 and one or more non-web support stacks 40.

[0101] For example Figure 3a and Figure 3b As shown, the first spar cap 30a and the second spar cap 30b are opposite each other, and the shear web 24 is connected between the first spar cap 30a and the second spar cap 30b. The first mounting flange 28a of the shear web 24 is bonded to the inner side of the first half shell 12a in the region of the web support stack 38 of the first spar cap 30a, for example using an adhesive 41. The second mounting flange 28b is bonded to the inner side of the second half shell 12b in the region of the second spar cap 30b.

[0102] The mounting flanges 28a, 28b advantageously provide increased surface area for bonding the shear web 24 to the inside of the first and second half shells 12a, 12b. Accordingly, the first and second mounting flanges 28a, 28b are preferably wider in the chordwise direction (C) than the web face sheet 26. This helps to safely distribute the loads transferred between the spar caps 30a, 30b and the shear web face sheet 26 during use, and also helps to stabilize the shear web 24.

[0103] The reinforcement strips 36 in the first spar cap 30a are arranged to provide the necessary structural reinforcement to the blade 10. Advantageously, the number of strips 36 in each stack 38, 40 may vary depending on the structural reinforcement requirements of a particular portion of the blade 10. For example, Figure 3a As shown, at a first spanwise location A along the blade 10 , the number of straps 36 in the web support stack 38 of the first spar cap 30 a is different from the number of straps 36 in the non-web support stack 40 .

[0104] Still refer to Figure 3a In some examples, at the first spanwise location A, the web support stack 38 of the first spar cap 30a may include a greater number of straps 36 than the non-web support stack 40. Thus, at the first spanwise location A, the web support stack 38 may provide additional structural reinforcement compared to the non-web support stack 40. In some other examples (not shown), at the first spanwise location A, the web support stack 38 may include fewer straps 36 than the non-web support stack 40. In such examples, at the first spanwise location A, the non-web support stack 40 may provide more structural reinforcement than the web support stack 38.

[0105] The difference in the number of straps 36 in the stacks 38, 40 at the first spanwise location A may result in the height of the web-supported stack 38 being different from the height of the non-web-supported stack 40. Figure 3a As shown, at a first spanwise location A, the thickness of the first spar cap 30a may vary across its full width in the chordwise direction (C).

[0106] Now refer to Figure 3b At a second spanwise location B along the blade 10, the number of straps 36 in the web support stack 38 of the first spar cap 30a may be the same as the number of straps 36 in the non-web support stack 40. Thus, at the second spanwise location B, the first spar cap 30a may have a substantially constant thickness across its entire chord-wise width.

[0107] As described above, according to the examples described herein, the arrangement of the reinforcement material, ie, the arrangement of the reinforcement material strips 36 , can be customized according to the structural reinforcement requirements of one or more specific portions of the blade 10 . For example, referring to Figure 3a and Figure 3b For example, the configuration of the first spar cap 30a allows for placement of more reinforcement material (strips 36) in areas where additional reinforcement is needed, without unnecessarily including additional reinforcement material where it is not needed, thereby helping to minimize the weight and cost of the blade 10. In particular, by varying the number of strips 36 in the web-supported and non-web-supported stacks 38, 40 relative to each other at a given spanwise location, rather than across the entire width of the spar cap 30a, the amount of reinforcement material in each stack 38, 40 can be tailored, which facilitates more fine-tuning of the amount and location of reinforcement material in the blade 10.

[0108] Still refer to Figure 3a and Figure 3b The initial examples in , and in particular Figure 3aAs shown in the detailed view in FIG, in some examples, arranging the reinforcement material strips 36 in side-by-side stacks 38, 40 can result in the strips 36 being arranged in multiple layers 42. Referring to the inner skin 32a and the outer skin 34a of the first half-shell 12a, the innermost layer 42a refers to the layer of strips 36 adjacent to or closest to the inner skin 32a, and the outermost layer 42b refers to the layer of strips 36 adjacent to or closest to the outer skin 34a. In some examples, the outermost layer 42b can include a greater number of strips 36 than the innermost layer 42a. Furthermore, in some preferred examples, each layer 42 of the first spar cap 30a can include the same number of strips 36, except for one or more innermost layers 42a that include fewer strips 36.

[0109] As previously mentioned, in some examples, the web support stack 38 may include more strips 36 of reinforcement material than each non-web support stack 40, i.e., the web support stack 38 may include additional strips 36 as compared to each non-web support stack 40. Figure 3a Conversely, in some other examples (not shown), each non-web support stack 40 may include more reinforcing material strips 36 than the web support stack 38, i.e., each non-web support stack 40 may include additional strips 36 compared to the web support stack 38. Figure 3a It will be appreciated that the "additional strip 36" in each example preferably forms the innermost layer 42a of strips.

[0110] In a preferred example, the strips 36 forming the innermost layer 42a of the first spar cap 30a (i.e., the additional strips 36) may be strips only within the web-supported stack 38, or in other examples, the strips 36 forming the innermost layer 42a may be strips 36 only within the non-web-supported stack 40. Thus, the innermost layer 42a of strips is preferably formed from strips 36 within a single type of stack, either the web-supported stack 38 or the non-web-supported stack 40, depending on the structural requirements of the blade 10.

[0111] It will be appreciated that the or each strip 36 in a given layer 42 does not necessarily extend along the entire length of the spar cap 30a. For example, the length of the reinforcement strips 36 may vary between different layers 42 in the first spar cap 30a. Figure 4a and Figure 4b As shown in the side view of the stacks 38, 40 in FIG. 4 , the strips 36 of reinforcement material in each innermost layer 42a may be shorter than the strips 36 in each outermost layer 42b of the corresponding stacks 38, 40. Furthermore, in some examples, the thickness of the spar caps 30a may taper toward the root end 16 and / or toward the tip end 18 of the blade 10, i.e., the first spar cap 30a may include a tapered root end portion 44 and / or a tapered tip end portion 46 (e.g., FIG. Figure 2In such an example, the strips 36 in each layer may gradually shorten from the outermost layer 42b to the innermost layer 42a to form a tapered root end portion 48 and / or a tapered tip end portion 50 of the stack 38, 40. It should be understood that Figure 4a and Figure 4b The side view in FIG. 1 shows the stacks 38 , 40 in isolation, and other features, such as the inner and outer skins 32 , 34 and any core material of the composite half shell 12 , are omitted for clarity.

[0112] To provide more context regarding the first spanwise position A and the second spanwise position B, in addition to Figure 4a and Figure 4b In addition, we briefly refer to Figure 2 . Figure 4a is a side view of the web support strip stackup of the first spar cap, Figure 4b is a side view of the non-web support strip stack of the first spar cap. As shown in these figures, the first spanwise location A is preferably in the center portion 52 of the blade 10. In contrast, the second spanwise location B may be between the tip end 18 and the center portion 52 of the blade. Although not identified in the figures, in some other examples, the second spanwise location B may be between the root end 16 and the center portion 52 of the blade. In some examples, the features described with respect to the second spanwise location B may apply equally to both the spanwise location between the root end 16 and the center portion 52 and the spanwise location between the tip end 18 and the center portion 52.

[0113] In some examples, the center portion 52 may have a spanwise extent of between 10-40% of the total length of the spar cap 30a. The first spar cap 30a may have a maximum thickness t at the center portion 52. max In some examples, the first spar cap 30a may have a substantially constant maximum thickness t throughout the center portion 52. max It will be appreciated that in some examples, the tapered root end portion 44 and / or the tapered tip end portion 46 of the first spar cap 30 a may therefore be external to the central portion 52 .

[0114] Reference again Figure 3a and Figure 3bIn the example shown in FIG. 5 , the first spar cap 30a may include a web support stack 38 defining a chord-wise center of the first spar cap 30a. In addition, the spar cap 30a may include a non-web support stack 40 on a leading edge side of the web support stack 38 and a non-web support stack 40 on a trailing edge side of the web support stack 38. In this arrangement, the non-web support stack 40 of the first spar cap 30a defines a longitudinal edge 54 of the first spar cap 30a. It should be understood that in some other examples (not shown), the spar cap 30a may include a plurality of web support stacks 38 defining a chord-wise center of the spar cap 30a and / or one or more non-web support stacks 40 on each of the leading edge side or the trailing edge side of the web support stack 38.

[0115] Figure 5a and Figure 5b The schematic cross-sectional view in shows another configuration of the stacks 38 , 40 in the first spar cap 30a in another example. Figure 5a and Figure 5b 1 and 2. A cross section is shown taken at a first spanwise position A and a second spanwise position B of a wind turbine blade 10 similar to that previously described with reference to FIG. Figures 1 to 4b The blade 10 is described.

[0116] In addition to the first shear web 24, Figure 5a and Figure 5b The blade shown in the example of also includes a second shear web 24. It will be appreciated that in addition to the arrangement including the second shear web 24 and the strip stacks 38, 40 forming the first spar cap 30a, Figure 5a and Figure 5b The blade 10 shown in FIG has the same features previously described with reference to the aforementioned figures. The second shear web 24 is constructed in substantially the same manner as the aforementioned first shear web 24 and will not be described in further detail. Similarly, other equivalent features will not be described again to avoid repetition.

[0117] like Figure 5a and Figure 5b As shown, in some examples, the first spar cap 30a can include a first web support stack 38 supporting the first shear web 24 and a second web support stack 38 supporting the second shear web 24. Additionally, the first spar cap 30a can include one or more non-web support stacks 40 disposed between the first web support stack 38 and the second web support stack 38. Thus, in such an arrangement, the web support stack 38 can define a longitudinal edge 54 of the first spar cap 30a. In such an example, the spar caps 30a, 30b and the shear webs 24 can advantageously form a box-shaped spar structure that provides increased rigidity and structural reinforcement to the blade shell 14.

[0118] With the previous reference Figures 2 to 4b In the same manner as described in the example of , at the first spanwise position A, the number of straps 36 in the web support stack 38 of the first spar cap 30a is different from the number of straps 36 in the or each non-web support stack 40. Also, similar to the previously described example, in e.g. Figure 5b At the second spanwise position B shown, the number of straps 36 in the web support stack 38 is preferably the same as the number of straps 36 in the non-web support stack 40 .

[0119] It will be appreciated that the above examples each include a single web support stack 38 supporting the or each shear web 24. However, as briefly noted above, in some examples (not shown), the or each shear web 24 may be supported by a plurality of web support stacks 38. Such a configuration may help the stacks 38, 40 of the first spar cap 30a conform to the contours of the blade shell 14.

[0120] It should be understood that the description provided above with reference to the example where the or each shear web 24 is supported by a single web support stack 38 is equally applicable to the example where the or each shear web 24 is supported by a plurality of web support stacks 38. Figures 2 to 4b Provided the description provided, it should be understood that, in some examples, reference to "the" web support stack 38 may be equivalent to reference to "the or each" web support stack. Figure 5a and Figure 5b In the description provided as an example, it should be understood that reference to “one” or “the” first web support stack 38 and “one” or “the” second web support stack 38 can be equivalent to reference to “the or each” first web support stack 38 and “the or each” second web support stack 38.

[0121] In addition, although Figure 5a and Figure 5b Although not shown in the example, in the example where the first spar cap 30a includes one or more first web support stacks 38 supporting the first shear web 24 and one or more second web support stacks 38 supporting the second shear web 24, the spar cap 30a may also include one or more non-web support stacks 40 on the leading edge side of the first web support stacks 38 and one or more non-web support stacks 40 on the trailing edge side of the second web support stacks 38. In such an example, such non-web support stacks 40 may define the longitudinal edges 54 of the spar cap 30a.

[0122] Finally, while the first spar cap 30a has been described in detail, it should be understood that in some examples, the second spar cap 30b of the blade 10 may include a web-supported stack 38 and a non-web-supported stack 40 arranged in a manner similar to the example of the first spar cap 30a described above. It should be noted that in such examples, the arrangement of the stacks 38, 40 for the second spar cap 30b may not necessarily be identical to that of the first spar cap 30a. For example, different sides of the blade 10 (i.e., the windward side and the leeward side) may experience different loads during use. Accordingly, one of the first or second spar cap 30a, 30b may be configured with more structural reinforcement than the other spar cap 30a, 30b to handle higher loads during use.

[0123] Figure 6 A first wind turbine blade 10i and a second wind turbine blade 10ii are shown, which are part of a series 56 of wind turbine blades having substantially equal lengths and substantially the same external shape. The first blade 10i is designed for a first wind turbine operating in a first wind class and / or having a first power rating, while the second blade 10ii is designed for a second wind turbine operating in a second wind class and / or having a second power rating. The first and second wind classes and / or power ratings are different, and therefore the structural reinforcement requirements for the first blade 10i and the second blade 10ii are also different, as previously mentioned in the background.

[0124] In some examples, the first wind turbine blade 10i and / or the second wind turbine blade 10ii in the series 56 may be a blade such as previously referenced. Figures 1 to 5b Thus, in some examples, the previously referenced Figures 1 to 5b The features of the blade 10 described by way of example are equally applicable to Figures 6 to 8b The first blade 10i and the second blade 10ii of the series 56 are shown in FIG. It should be understood that in order to avoid repetition, equivalent features will not be described in detail. Figures 6 to 8b The first blade 10i and the second blade 10ii are described.

[0125] For the avoidance of doubt, the first wind turbine blade 10i and the second wind turbine blade 10ii each include a blade shell 14 that extends longitudinally in the spanwise direction (S) from a root end 16 to a tip end 18 and transversely in the chordwise direction (C) between a leading edge 20 and a trailing edge 22. Figures 7a to 7c As best shown in the schematic cross-sectional view of FIG, the blade shell 14 of each blade 10i, 10ii is formed from opposing first and second half shells 12a, 12b.

[0126] Furthermore, the first blade 10i and the second blade 10ii each comprise a first spar cap 30a associated with the first half-shell 12a and a second spar cap 30b associated with the second half-shell 12b. Figures 1 to 5b As shown in the example of FIG, the first spar cap 30a includes a plurality of side-by-side stacks 38 , 40 of longitudinally extending reinforcement material strips 36 , and the stacks include at least one web-supported stack 38 and at least one non-web-supported stack 40 .

[0127] In a preferred example, and for example Figure 7a and Figure 7b As shown, the corresponding first spar caps 30ai, 30aii of the first blade 10i and the second blade 10ii in the series 56 have the same number of stacks 38, 40. In particular, the corresponding spar caps 30ai, 30aii preferably each have the same number of web support stacks 38. Figure 7a and Figure 7b In the example shown, the respective first spar caps 30a, 30aii each have three side-by-side stacks 38, 40 and each have a single web support stack. Therefore, the respective first spar caps 30ai, 30aii preferably have the same size (width) in the chordwise direction (C).

[0128] However, as previously mentioned, the structural reinforcement requirements of the first blade 10i and the second blade 10ii may be different, even though the blades have substantially equal lengths and substantially the same external shape. Therefore, the first spar cap 30ai of the first blade 10i is constructed differently from the first spar cap 30aii of the second blade 10ii. Figure 7a and Figure 7b As shown in the cross-sectional view of FIG, at the first spanwise position A, the number of strips 36 in the non-web support stack 40ai of the first spar cap 30a of the first blade 10i is different from the number of strips 36 in the corresponding non-web support stack 40aii of the first spar cap 30aii of the second blade 10ii.

[0129] For example, the first blade 10i may be designed for a wind turbine operating in higher wind levels, and therefore, at the first spanwise position A, the non-web support stack 40ai of the first spar cap 30aii of the first blade 10i may have more straps 36 than the corresponding non-web support stack 40aii of the first spar cap 30aii of the second blade 10ii. This may result in the non-web support stack 40ai of the first blade 10i having a greater stack height than the corresponding non-web support stack 40aii of the second blade 10ii. The additional straps 36 in the first spar cap 30ai of the first blade 10i may provide more structural reinforcement, allowing the first blade 10i to safely operate in higher wind conditions than the second blade 10ii.

[0130] In a preferred example, the second spar caps 30bi, 30bii of the first and second blades 10i, 10ii may also include a plurality of side-by-side stacks 38, 40 of longitudinally extending reinforcement material strips 36. The second spar caps 30bi, 30bii of each blade 10i, 10ii may be constructed in a substantially similar manner to the first spar caps 30ai, 30aii, but not necessarily identically, and therefore will not be described in detail to avoid repetition. Figure 7a and Figure 7b As shown, each blade 10i, 10ii in the series 56 also includes a shear web 24 connected between the first and second opposing spar caps 30ai, 30aii, 30bii (e.g., between the opposing web support stacks 38ai, 38bi and 38aii, 38bii). As will now be described, in some advantageous examples, the shear web 24 of the first blade 10i can be substantially identical to the shear web 24 of the second blade 10ii.

[0131] In some examples, along the lengths of the first and second spar caps 30a, 30b, the spacing between the web support stacks 38ai, 38bi of the first and second spar caps 30ai, 30bi of the first blade 10i can be substantially the same as the spacing between the web support stacks 38aii, 38bii of the first and second spar caps 30aii, 30bii of the second blade 10ii. This means that the same shear web design and tooling can be used for the shear webs 24 of both the first and second blades 10i, 10ii, even though the blades and their spar caps 30ai, 30bi, 30aii, 30bii are designed and manufactured to different structural reinforcement requirements. In some examples, this can significantly reduce the time and cost of developing and manufacturing different blades 10i, 10ii within a blade family 56 for different operating conditions.

[0132] To provide the necessary structural reinforcement to the first and second blades 10i, 10ii, the corresponding non-web support stacks 40 of each blade have different numbers of reinforcement strips 36, as previously described. This means that in some examples, along at least a portion of the length of the spar caps 30ai, 30bi, 30aii, 30bii, the spacing between the non-web support stacks 40ai, 40bi of the first and second spar caps 30ai, 30bi of the first blade 10i may be different from the spacing between the corresponding non-web support stacks 40aii, 40bii of the first and second spar caps 30aii, 30bii of the second blade 10ii. Figure 7a and Figure 7b An example of this spacing difference at a first spanwise position A is shown.

[0133] The configuration of the or each non-web support stack 40ai, 40aii of the first spar cap 30ai, 30aii of the first and second blades 10i, 10ii is tailored to the structural requirements of the respective blades. Thus, in some parts of the blades 10i, 10ii, there may be differences in the number of strips 36 in the corresponding non-web support stacks 40ai, 40aii. However, in other parts of the blades 10i, 10ii, the structural requirements for both blades may be substantially the same. For example, Figure 7c A schematic cross-sectional view is shown of a second spanwise position B of both the first blade 10i and the second blade 10ii of the series 56. As can be seen in this example, at the second spanwise position B, the number of straps 36 in the or each non-web support stack 40ai of the first spar cap 30ai of the first blade 10i may be the same as the number of straps 36 in the or each corresponding non-web support stack 40aii of the first spar cap 30aii of the second blade 10ii.

[0134] As previously referenced Figures 1 to 5b As described in the example of FIG. 1 , the first spanwise location A may be in the central portion 52 of the blade 10i, 10ii. The spanwise location A and the central portion 52 are Figures 8a to 8c is shown in a side view. Figure 8a shows a side view of the non-web support stack 40ai of the first blade 10i, Figure 8b A side view of the non-web support stack 40aii of the second blade 10ii is shown, and Figure 8c The web support stacks 38ai / 38aii of the first and second blades 10i, 10ii are shown.

[0135] refer to Figure 8a and Figure 8b Throughout the central portion 52, the or each non-web support stack 40ai of the first blade 10i may have a different height than the non-web support stack 40aii of the second blade 10ii. Outside of the central portion 52, i.e., excluding the central portion 52, the corresponding non-web support stacks 40ai, 40aii of the first and second blades 10i, 10ii may be substantially identical.

[0136] Still refer to Figure 8a and Figure 8b The corresponding non-web support stacks 40ai, 40aii of the first and second blades 10i, 10ii may each include a stack having a maximum height h max i、h max ii, and each stack may taper from a maximum height toward the respective root end 16 and tip end 18 of the blade 10, 10ii. Figure 8a and Figure 8bAs shown in the comparison with the corresponding non-web support stack 40ai of the second blade 10ii, the maximum stack height h max ii, the maximum stack height h of the non-web support stack 40ai of the first blade 10i is max i can be offset in the spanwise direction (S). This is because, as previously described, the strips 36 of the non-web support stacks 40ai, 40aii in different blades 10i, 10ii of the series 56 can be arranged differently to provide structural reinforcement in different specific portions of each blade 10i, 10ii as needed. In addition, as previously described, the (one or more) web support stacks 38ai, 38aii of each blade 10i, 10ii can be arranged in a substantially identical configuration, such as Figure 8c As shown, this facilitates the use of the same shear web 24 in each blade 10i, 10ii.

[0137] For reference, it should be understood that Figure 8a 、 Figure 8b and Figure 8c The side view in FIG shows the stack 40ai, 40aii, 38ai / 38aii in isolation, and other features such as the inner and outer skins of the composite half shells and any core material are omitted for clarity.

[0138] Figures 6 to 8b The configuration of the first spar caps 30ai, 30aii of the first blade 10i and the second blade 10ii of the series 56 shown in FIG is provided by way of example only. In particular, Figure 7a and Figure 7b The layout of the stacks 38, 40 in the example shown is substantially similar to that of the previously referenced Figure 3a and Figure 3b However, it should be understood that other stacking layouts (such as those described in reference Figure 5a and Figure 5b Those described and referenced Figures 1 to 5b Other optional configurations described herein may also be applied to blades in the wind turbine blade series 56, such as Figures 6 to 8b In addition, it should be understood that although Figures 6 to 8b The description is based on Figures 1 to 5b The description similarly focuses on the first spar caps 30ai, 30aii of the first and second blades 10i, 10ii, but in some examples, any description provided herein with reference to the first spar caps 30ai, 30aii may be equally applicable to the second spar caps 30bi, 30bii.

[0139] Finally, it should be understood that the description provided above is for illustrating multiple possible examples of the present invention. Features described with respect to any of the above examples can be easily combined with any other features described with reference to a different example without departing from the scope of the present invention as defined in the appended claims.

Claims

1. A wind turbine blade, comprising: a blade shell extending longitudinally in a spanwise direction from a root end to a tip end and extending transversely in a chordwise direction between a leading edge and a trailing edge, the blade shell being formed from opposing first and second half shells, the first and second half shells having a composite laminate structure; Each half shell comprises an inner skin on the inside of the blade shell and an outer skin on the outside of the blade shell; a first spar cap located between the inner skin and the outer skin of the first half shell, and a second spar cap located between the inner skin and the outer skin of the second half shell, the first spar cap and the second spar cap being opposite to each other; wherein the first spar cap comprises a plurality of side-by-side stacks of longitudinally extending strips of reinforcement material, the stacks comprising at least one web-supported stack and at least one non-web-supported stack; a shear web connected between the first and second spar caps, the shear web comprising a longitudinally extending web panel and a first mounting flange and a second mounting flange, the first mounting flange and the second mounting flange extending transversely to the web panel along respective longitudinal edges of the web panel, the first mounting flange being bonded to an interior of the first half-shell in the region of the web support stack of the first spar cap, and the second mounting flange being bonded to an interior of the second half-shell in the region of the second spar cap; Wherein, at a first spanwise position along the blade, the number of straps in the web-supported stack of the first spar cap is different from the number of straps in the non-web-supported stack of the first spar cap.

2. The wind turbine blade according to claim 1, wherein: At the first spanwise location, the height of the web support stack of the first spar cap is different from the height of the non-web support stack.

3. A wind turbine blade according to claim 1 or claim 2, wherein: At the first spanwise location, the web-supported stack of the first spar cap includes a greater number of straps than the non-web-supported stack.

4. A wind turbine blade according to claim 1 or claim 2, wherein: At the first spanwise location, the web-supported stack of the first spar cap includes fewer straps than the non-web-supported stack.

5. A wind turbine blade according to any one of the preceding claims, wherein At a second spanwise position along the blade, the number of straps in the web-supported stack and the number of straps in the non-web-supported stack of the first spar cap are the same.

6. The wind turbine blade according to claim 5, wherein: The first spanwise position is in a central portion of the blade and the second spanwise position is between a root end and the central portion of the blade and / or between a tip end and the central portion of the blade.

7. The wind turbine blade according to claim 6, wherein: The central portion has a spanwise extent of between 10-40% of the total length of the first spar cap.

8. A wind turbine blade according to claim 6 or claim 7, wherein: The first spar cap has a maximum thickness in the entire central portion of the blade, and outside the central portion, the thickness of the first spar cap tapers towards the root end of the blade and / or towards the tip end of the blade.

9. A wind turbine blade according to any one of claims 5 to 8, wherein: At the second spanwise position, the first spar cap has a substantially constant thickness across its width in the chordwise direction.

10. A wind turbine blade according to any one of the preceding claims, wherein At the first spanwise position, the thickness of the first spar cap varies across its width in the chordwise direction.

11. A wind turbine blade according to any one of the preceding claims, wherein The strips forming the first spar cap are arranged in a plurality of layers, and wherein the number of strips in an outermost layer adjacent to the outer skin is greater than the number of strips in an innermost layer.

12. The spar cap according to claim 11, wherein: The stripes in the innermost layer are shorter than the stripes in the outermost layer.

13. A wind turbine blade according to claim 11 or claim 12, wherein: The innermost layer of straps in the first spar cap may consist of straps only within a web support stack or only within a non-web support stack.

14. A wind turbine blade according to any one of claims 11 to 13, wherein: Each layer of the first spar cap includes the same number of straps except for one or more innermost layers, which include fewer straps, and those fewer straps are only within the web support stack or only within the non-web support stack.

15. A wind turbine blade according to any one of the preceding claims, wherein The first spar cap comprises: one or more web support stacks defining a chordwise center of said first spar cap; one or more first non-web support stacks on the leading edge side of the web support stack; and One or more second non-web support stacks on the trailing edge side of the web support stack.

16. The wind turbine blade of claim 15, wherein: The non-web support stack of the first spar cap defines a longitudinal edge of the first spar cap.

17. A wind turbine blade according to any one of claims 1 to 14, wherein: The first spar cap comprises: one or more first web support stacks supporting a first shear web; one or more second web support stacks supporting a second shear web; and One or more non-web support stacks are disposed between the first web support stack and the second web support stack.

18. The wind turbine blade of claim 17, wherein: The web support stack of the first spar cap defines a longitudinal edge of the first spar cap.

19. A wind turbine blade according to any one of the preceding claims, wherein The first and second mounting flanges of the shear web are wider in the chordwise direction than the web face plate.

20. A wind turbine blade according to any one of the preceding claims, wherein The strips of reinforcement material have an aspect ratio of at least 10:1 and preferably at least 20:1, wherein the aspect ratio is defined as the ratio of the width of the strip in the chord-wise direction to the thickness of the strip.

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