Patent Grant
10077758
The present subject matter relates generally to wind turbines and, more particularly, to pre-cured laminate plates having corrugations or channels formed therein to allow the plates to conform to the chordwise curvature of a wind turbine rotor blade during the manufacturing process of the blade.
Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from wind using known foil principles and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
Wind turbine rotor blades typically include a body shell formed from a composite laminate material. In general, the body shell is relatively lightweight and has structural properties (e.g., stiffness, buckling resistance and strength) which are not configured to withstand the bending moments and other loads exerted on the rotor blade during operation. In addition, wind turbine blades are becoming increasingly longer in order to produce more power. As a result, the blades must be stiffer and thus heavier so as to mitigate loads on the rotor.
To increase the stiffness, buckling resistance and strength of the rotor blade, the body shell is typically reinforced using one or more structural components (e.g. opposing spar caps with a shear web configured therebetween) that engage the inner surfaces of the shell. The spar caps are typically constructed from laminate composites (e.g., glass fiber laminate composites and/or carbon fiber laminate composites) that include dry or non-cured fabric plies that are laid up within the blade mold and subsequently infused with resin. Such materials, however, can be difficult to control during the manufacturing process and/or are often defect prone and/or highly labor intensive due to handling of the non-cured fabrics and the challenges of infusing large laminated structures.
As such, recent attempts have been made to form spar caps from pre-fabricated, pre-cured laminate composites that can be produced in thicker sections, and are typically less susceptible to defects. However, the use of these thicker, pre-cured laminates also presents unique challenges during the blade manufacturing process. For example, the thicker pre-cured laminates present challenges with respect to conforming the individual laminate plies to the desired curvature of the blade due to the stiffness of such plies.
Accordingly, pre-cured laminate plates that include features to allow the plates to better conform to the desired chordwise curvature of a wind turbine rotor blade during the manufacturing process would be welcomed in the technology.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one aspect, the present subject matter is directed to a component for a wind turbine rotor blade. The component may generally include an assembly of pre-cured laminate plates. Each pre-cured laminate plate may include a plate body formed from a combination of fibers and resin. The plate body may extend in a thickness direction between a first side and a second side and in a widthwise direction between a first end and a second end. The plate body may define a maximum plate thickness in the thickness direction between the first and second sides. Each pre-cured laminate plate may also include a plurality of channels formed in the plate body between the first and second ends. Each channel may extend in the thickness direction between a top end that is open along the first side of the plate body and a bottom end that terminates at a location between the first and second sides of the plate body such that the plate body defines a reduced thickness between the second side of the plate body and the bottom end of each channel.
In another aspect, the present subject matter is directed to a spar cap for a wind turbine rotor blade. The spar cap may generally include an assembly of pre-cured laminate plates. Each pre-cured laminate plate may include a plate body formed from a combination of fibers and resin. The plate body may extend in a thickness direction between a first side and a second side and in a widthwise direction between a first end and a second end. The plate body may define a maximum plate thickness in the thickness direction between the first and second sides. Each pre-cured laminate plate may also include a plurality of channels formed in the plate body between the first and second ends. Each channel may extend in the thickness direction between a top end that is open along the first side of the plate body and a bottom end that terminates at a location between the first and second sides of the plate body such that the plate body defines a reduced thickness between the second side of the plate body and the bottom end of each channel.
In a further aspect, the present subject matter is directed to a rotor blade for a wind turbine. The rotor blade may generally include a blade root, a blade tip and a body shell extending between the blade root and the blade tip. The rotor blade may also include a structural component positioned within the body shell. The structural component may be formed from at least one pre-cured laminate plate. The pre-cured laminate plate(s) may include a plate body formed from a combination of fibers and resin. The plate body may extend in a thickness direction between a first side and a second side and in a widthwise direction between a first end and a second end. The plate body may define a plate thickness in the thickness direction between the first and second sides. The pre-cured laminate plate(s) may also include a plurality of channels formed in the plate body between the first and second ends. Each channel may extend in the thickness direction between a top end that is open along the first side of the plate body and a bottom end that terminates at a location between the first and second sides of the plate body such that the plate body defines a reduced thickness between the second side of the plate body and the bottom end of each of the plurality of channels.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
In general, the present subject matter is directed to corrugated, pre-cured laminate plates configured to use within a wind turbine rotor blade. Specifically, in several embodiments, the corrugated plates may be utilized to form one or more of the structural components of a rotor blade, such as one or more of the blade's spar caps. However, in other embodiments, the corrugated plates may be utilized to form any other suitable section, component and/or feature of a wind turbine rotor blade. For instance, the corrugated plates may be used to form all or a portion of the blade root of the rotor blade.
As will be described below, a plurality of corrugations or channels may be formed within each pre-cured laminate plate, with each channel being configured to extend lengthwise along its respective plate. For instance, in several embodiments, the channels may be configured to extend lengthwise in a direction parallel to the fiber direction of each pre-cured laminate plate. As such, when the plates are used to form the spar caps of a rotor blade, the channels may extend generally spanwise along the length of the rotor blade.
In several embodiments, the channels may be formed within each pre-cured laminate plate so as to form a region of lower thickness within the plate across the limited chordwise width of each channel. For example, in a particular embodiment, the channels may be formed within each pre-cured laminate plate such that the thickness of the plate at each channel is less than 75% of the overall thickness of the plate. By providing such lower thickness regions across the chordwise width of the plates, the plates may more easily take the shape of or conform to the desired curvature of the rotor blade, thereby enhancing the blade manufacturing process when using pre-cured laminate plates (particularly relatively thick pre-cured laminate plates).
Moreover, in several embodiments, a plurality of openings may be defined in each pre-cured laminate plate along the length of each channel. Such openings may further enhance the ability of each plate to conform to the desired chordwise curvature of the rotor blade being manufactured. In addition, the openings may also promote better through-thickness resin transfer during a subsequent infusion process.
It should be appreciated that, in several embodiments, the pre-cured laminate plates of the present subject matter may correspond to pultruded plates. As is generally understood, “pultruded composites” or “pultrusions” generally encompass reinforced materials (e.g. fibers or woven or braided strands) that are impregnated with a resin and pulled through a heated stationary die such that the resin cures or undergoes polymerization. As such, the process of manufacturing pultruded composites is typically characterized by a continuous process of composite materials that produces composite parts having a constant cross-section. However, in other embodiments, the pre-cured laminate plates described herein may be formed using any other suitable process, such as a belt-pressing manufacturing process.
Referring now to the drawings,
Referring now to
As shown, the rotor blade 22 generally includes a blade root 24 configured to be mounted or otherwise secured to the hub 20 (
In several embodiments, the body shell 28 of the rotor blade 22 may be formed from a plurality of shell components or sections. For example, in one embodiment the body shell 28 may be manufactured from a first shell half or section generally defining the pressure side 32 of the rotor blade 22 and a second shell half or section generally defining the suction side 34 of the rotor blade 22, with such shell sections being secured to one another at the leading and trailing ends 36, 38 of the blade 22. Alternatively, the body shell 28 may be formed from any other suitable number and/or arrangement of shell sections. For instance, in one embodiment, the body shell 28 may be segmented along the longitudinal axis 30 of the rotor blade 22, with each spanwise segment being formed from one or more shell sections.
Additionally, the body shell 28 may generally be formed from any suitable material. For instance, in one embodiment, the body shell 28 may be formed entirely from a laminate composite material, such as a carbon fiber reinforced laminate composite or a glass fiber reinforced laminate composite. Alternatively, one or more portions of the body shell 28 may be configured as a layered construction and may include a core material, formed from a lightweight material such as wood (e.g., balsa), foam (e.g., extruded polystyrene foam) or a combination of such materials, disposed between layers of laminate composite material.
Referring particularly to
Referring now to
In several embodiments, each pre-cured plate 100 may correspond to a pultruded plate. In such embodiments, one or more fiber materials 102 (e.g., glass or carbon fibers) may be cured during the manufacturing process to form each individual pultruded plate. For example, the fibers 102 may be impregnated with at least one resin material 104 using any suitable means. In particular embodiments, the resin material 104 may include any suitable resin, including but not limited to polyester, polyurethane, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), vinyl ester, epoxy, or similar. The impregnated fibers 102 may then be pulled through a heated stationary die such that the resin 104 cures or undergoes polymerization to form each plate 100. The individually formed plates 100 may then be assembled or joined together (e.g., via a secondary infusion process) to form the resulting spar cap 46. For example, as shown in the illustrated embodiment of
It should be appreciated that, in several embodiments, the plates 100 may be stacked directly one on top of another to form the spar cap 46. Alternatively, a thin mat or fiber layer (e.g., a low weight glass bale) may be positioned between adjacent plates 100. In such an embodiment, the thin fiber layer may be adapted to facilitate improved adhesion and/or resin transfer between the adjacent plates 100.
As particularly shown in
Additionally, as particularly shown in
Referring now to
In general, the plate 100 may include a plate body 114 formed by the combination of the fibers 102 and resin 104 described above with reference to
Additionally, as indicated above, the plate 100 may include plurality of channels 110. As shown in the illustrated embodiment, the channels 110 may be formed in the plate body 114 between its first and second ends 124, 126 so as to extend lengthwise along the longitudinal direction 128 of the plate 100. As such, each channel 110 may generally extend lengthwise in a direction that is parallel to the fiber direction 108 of the fibers 102.
It should be appreciated that, in general, any suitable number of channels 110 may be defined in the plate body 114, with the channels 110 having any suitable spacing along widthwise direction 122 of the plate 100. For example, in the illustrated embodiment, the plate 100 includes five equally spaced channels 110 defined in the plate body 114. However, in other embodiments, the plate 100 may include less than five channels 110 or more than five channels 110 and/or may have variable spacing along the widthwise direction 122 of the plate 100. For example, the particular number and/or widthwise spacing of the channels 110 may generally be selected so as to allow the shape of the plate 100 to be conformed to the particular blade curvature along which the plate 100 is being assembled.
As particularly shown in
Due to the configuration of the channels 110, the plate body 114 may generally define a region of reduced thickness at or adjacent to each channel 110. For example, as shown in
The reduced thickness region formed at or adjacent to each channel 110 may generally allow the plate 100 to be conformed to the desired curvature of a rotor blade 22 without requiring the application of excessive force against the plate 100 during the manufacturing process, thereby reducing the strain experienced by the plate 100. Specifically, the channels 110 may allow for a reduction in the stiffness of the plate 100 along its widthwise direction 112, thereby allowing the plate 110 to be flexed or to otherwise take the shape of the chordwise curvature of the rotor blade 22. As such, significantly thicker plates may be used to form a given wind turbine component (e.g., spar cap), which may allow for a reduction in the overall costs associated with manufacturing such component.
It should be appreciated that, when assembling multiple plates 100 to form a given wind turbine component (e.g., a spar cap), the plates 100 may define the same or differing thicknesses 136. For instance, in the embodiment shown in
Moreover, it should be appreciated that the channels 110 may generally be configured to define any suitable cross-sectional shape. For example, in the illustrated embodiment, the channels 110 define triangular or pyramidal cross-sectional shapes. However, in other embodiments, the channels 110 may define any other suitable cross-sectional shapes. For instance,
It should also be appreciated that the channels 110 may generally be formed within the plate body 114 using any suitable process and/or means. In one embodiment, the channels 110 may be formed simultaneously with the forming of the plate body 114. For instance, when the plates 100 correspond to pultruded plates, the die used to manufacture each plate 100 may be designed to include suitable features such that, when the infused fibers 102 are pulled through the die, a plate body 114 is formed that includes channels 110 defined therein. Alternatively, the channels 110 may be formed after the manufacturing of the plate body 110. For instance, the channels 110 may be machined into the pre-formed plate body 110 using any suitable machining process.
Additionally, as indicated above, the plate body 114 may also include a plurality of perforations or openings 112 spaced apart along the length of each channel 110, with each opening 112 extending between its corresponding channel 110 and the opposed side of the plate body 114. For instance, as shown in
Moreover, as shown in
Additionally, it should be appreciated that, when the disclosed plates 100 are assembled or stacked to form a given wind turbine component (e.g., a spar cap), the channels 110 may be formed in each plate 100 at the same or at differing locations relative to the channels 110 of the other plates 100. For instance, as shown in the embodiment of
It should also be appreciated that, although the plates 100 were generally described herein as including channels 110 formed along one side of the plate body 114, each plate 100 may, instead, include one or more channels 110 formed on both sides of the plate body 114. For instance,
Alternatively, the channels 110, 111 may be formed along the first and second sides 118, 120 of the plate body 114 so as to be aligned with one another along the widthwise direction 122 of the plate body 114. For instance,
As indicated above, it should be appreciated that, although the present subject matter has generally been described herein with reference to the use of the disclosed plates 100 in forming a spar cap of a rotor blade, the plates 100 may be utilized to form any other suitable structural component of a wind turbine 10. For instance, in one embodiment, the plates 100 may be used to form any other structural component that is desired to conform to the curvature of the rotor blade and/or that otherwise is desired to have a curved profile, such as an auxiliary spar cap or any other structural member that is placed adjacent to the body shell 28 of the rotor blade 22 (e.g., a structural patch that only extends along a portion of the span 40 of the rotor blade 22).
It should also be appreciated that, as indicated above, the plates 100 may also be utilized to form any other suitable section, component and/or feature of a wind turbine rotor blade. For instance, in one embodiment, the flexibility provided by the disclosed plates 100 may allow the plates to conform to the curved shape of the blade root 24 of a rotor blade 22. In such an embodiment, the plates 100 may be utilized, for example, to build-up the thickness of the blade root 24 and/or to completely form the entire blade root 24.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
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