Patent Description:
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, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades are the primary elements for converting wind energy into electrical energy. The blades have the cross-sectional profile of an airfoil such that, during operation, air flows over the blade producing a pressure difference between the sides. Consequently, a lift force, which is directed from a pressure side surface towards a suction side surface, acts on the blade. The lift force generates torque on the main rotor shaft, which is geared to the generator for producing electricity.

The rotor blades typically consist of a suction side shell and a pressure side shell that are bonded together at bond lines along the leading and trailing edges of the blade. An internal shear web extends between the pressure and suction side shell members and is bonded to opposing spar caps affixed to the inner faces of the shell members. With typical blade configurations, the spar caps are continuous members that span the length of the rotor blade.

Many of the blade components are constructed of a composite laminate materials optionally reinforced with one or more fiber materials, e.g. via a resin infusion process. For example, conventional spar caps are formed using a vacuum-assisted resin transfer molding (VARTM). The VARTM process is a technique that uses vacuum pressure to drive resin into a mold. More specifically, plies or pultruded plates may be laid into the mold and covered with an infusion bag. Vacuum is then applied and resin is introduced into the spar cap mold to form the spar caps.

Once the pultruded plates are machined, however, transportation to the spar cap mold can be difficult. In addition, during the manufacturing process, the pultruded plates may shift within the mold before the components are infused together.

<CIT> discloses a rotor blade component including an enclosed primary outer casing defining a hollow interior and a plurality of pultruded rods received within the hollow interior of the enclosed primary outer casing. <CIT> discloses a modular fibre reinforced plastic flange for a wind turbine blade comprising an array of elongate elements. <CIT> discloses a reinforcing structure in the form of an elongate stack of layers of pultruded fibrous composite strips supported within a U-shaped channel. Accordingly, the industry would benefit from an improved manufacturing process for spar caps that addresses the aforementioned issues.

In one aspect, the present disclosure is directed to a method for manufacturing a spar cap of a rotor blade of a wind turbine. The method includes forming an outer frame of the spar cap via at least one of three-dimensional (3D) pultrusion or 3D printing. As such, the outer frame has a varying cross-section that corresponds to a varying cross-section of the rotor blade along a span thereof. The method also includes arranging a plurality of structural materials within the outer frame of the spar cap. Further, the plurality of structural materials may include thermoplastic or thermoset plies or pultruded members. Another step includes infusing the plurality of structural materials and the outer frame together via a resin material so as to form the spar cap and allowing the spar cap to cure.

In one embodiment, the step of pultruding the outer frame of the spar cap may include pultruding the outer frame from a thermoplastic material reinforced with one or more fiber materials. In such embodiments, the fiber material(s) may include glass fibers, carbon fibers, metal fibers, polymer fibers, ceramic fibers, nanofibers, wood fibers, bamboo fibers, or combinations thereof.

In another embodiment, the step of pultruding the outer frame of the spar cap may include pultruding extended side edges of the outer frame. As such, in certain embodiments, the extended side edges may be configured as shear clips for attaching to a shear web of the rotor blade.

Alternatively, the method may include folding the extended side edges towards a center of the outer frame so as to retain the plurality of structural materials therein. In still alternative embodiments, the method may include folding the extended side edges away from a center of the outer frame to create opposing flanges of the outer frame and securing the flanges to the pressure side surface or the suction side surface of the rotor blade.

In further embodiments, the method may include removing the extended side edges from the outer frame. In additional embodiments, the method may include arranging a plurality of layers of the structural materials within the outer frame of the spar cap and arranging one or more non-structural layers between the layers of structural materials, the one or more non-structural materials comprising at least one of a glass veil, a continuous fiber mat, or a fabric material.

In another aspect, the method is directed to a method for manufacturing a spar cap of a rotor blade of a wind turbine. The method includes forming an outer frame of the spar cap. Further, the method includes machining a plurality of structural materials (e.g. thermoplastic or thermoset plies or pultruded members). Moreover, the method includes dispensing the structural material(s) directly into the outer frame of the spar cap after machining. As used herein, machining may include, but is not limited to cutting, chamfering, surface preparing (e.g. chemical, mechanical, or other), scoring, cleaning, labeling, coating, or any other suitable machining process. Another step includes infusing the plurality of structural materials and the outer frame together via at least one of a thermoplastic or thermoset resin material so as to form the spar cap. In addition, the method includes allowing the spar cap to cure.

In one embodiment, the step of forming the outer frame of the spar cap may include heating a thermoset or thermoplastic material and forming the material into a desired blade shape. Alternatively, the step of forming the outer frame of the spar cap may include pultruding the outer frame of the spar cap, e.g. via 3D pultrusion. In another embodiment, the step of machining the plurality of structural materials may include, for example, laser-jet cutting or water-jet cutting. It should also be understood that the method may further include any of the additional steps and/or features as described herein.

In yet another aspect, the present disclosure is directed to a spar cap for a rotor blade of a wind turbine. The spar cap includes a thermoplastic fiber-reinforced outer frame having a base, perpendicular side walls extending from the base, and an open end opposite the base. Further, the spar cap includes a plurality of structural materials arranged within the outer frame. As mentioned, the structural material(s) may include thermoplastic or thermoset plies or pultruded members. Moreover, the spar cap includes a cured resin material securing the plurality of structure materials within the outer frame.

In one embodiment, the outer frame may be formed via a 3D pultrusion process. In such embodiments, the outer frame may have a varying cross-section that corresponds to a varying cross-section of the rotor blade along a span thereof.

In another embodiment, the side walls of the outer frame may have one or more perforated lines or slots configured to increase flexibility thereof. It should also be understood that the spar cap may further include any of the additional features as described herein.

In still another aspect, the present disclosure is directed to a method for manufacturing a rotor blade of a wind turbine. The method includes forming an outer frame of the spar cap via at least one of 3D pultrusion or 3D printing. As such, the outer frame has a varying cross-section that corresponds to a varying cross-section of the rotor blade along a span thereof. Further, the method includes arranging a plurality of structural materials within the outer frame of the first spar cap. The structural material(s) may include thermoplastic or thermoset plies or pultruded members. Another step includes securing the plurality of structural materials and the outer frame together so as to form the first spar cap. Further, the method includes joining the outer frame of the first spar cap to an inner surface of at least one of a pressure side surface or a suction side surface of the rotor blade.

In one embodiment, the step of joining the outer frame of the spar cap to the inner surface of the pressure side surface or the suction side surface of the rotor blade may include laying an outer skin layer of at least one of the pressure side surface or the suction side surface of the rotor blade into a shell mold, placing the outer frame of the spar cap adjacent to the outer skin, laying an inner skin layer of at least one of the pressure side surface or the suction side surface of the rotor blade atop the spar cap, and infusing the spar cap between the outer and inner skin layers.

In another embodiment, the method may include forming a second spar cap, joining one of the first and second spar caps to the pressure side surface and the other of the first and second spar caps to the suction side surface, and securing a shear web between the first and second spar caps.

In further embodiments, the method may include attaching one or more straps to extended side edges of the outer frame of the spar cap and placing the spar cap into the shell mold via the one or more straps. Alternatively, the method may include attaching one or more straps around the outer frame of the spar cap and placing the spar cap into the shell mold via the one or more straps.

In additional embodiments, the method may include securing one or more shear webs of the rotor blade to the extended side edges.

In yet another embodiment, the method may include folding the extended side edges towards a center of the outer frame so as to retain the plurality of structural materials therein (e.g. before infusion) and attaching a base of the outer frame to the inner surface of the pressure side surface or the suction side surface of the rotor blade. In alternative embodiments, the method may include folding the side edges away from the center of the outer frame to create opposing flanges and securing the flanges to the pressure side surface or the suction side surface of the rotor blade.

In still additional embodiments, the method may include removing the extended side edges from the outer frame. In further embodiments, the method may include arranging a plurality of layers of the structural materials within the outer frame of the spar cap and arranging one or more non-structural layers between the layers of structural materials, the one or more non-structural materials comprising at least one of a glass veil, a continuous fiber mat, or a fabric material.

It should also be understood that the method may further include any of the additional steps and/or features as described herein.

In a further aspect, the present disclosure is directed to a method for manufacturing a rotor blade of a wind turbine. The method includes forming an outer frame of the spar cap. Another step includes machining a plurality of structural materials, e.g. thermoplastic or thermoset plies or pultruded members. The method also includes dispensing the structural materials directly into the outer frame of the spar cap after machining. Further, the method includes infusing the plurality of structural materials and the outer frame together via at least one of a thermoplastic or thermoset resin material so as to form the spar cap. In addition, the method includes joining the outer frame of the spar cap to an inner surface of the pressure side surface or the suction side surface of the rotor blade.

In one embodiment, the step of joining the outer frame of the spar cap to the inner surface of the pressure side surface or the suction side surface may include laying an outer skin layer of at least one of the pressure side surface or the suction side surface of the rotor blade into a shell mold, placing the outer frame of the spar cap adjacent to the outer skin, laying an inner skin layer of at least one of the pressure side surface or the suction side surface of the rotor blade atop the spar cap, and infusing the spar cap between the outer and inner skin layers.

In yet another aspect, the present disclosure is directed to a rotor blade of a wind turbine. The rotor blade includes a blade shell extending between a blade root and a blade tip and having a pressure side surface and a suction side surface extending between a leading edge and a trailing edge. Further, the rotor blade includes opposing spar caps configured with each of the pressure side surface and the suction side surface. Moreover, each of the opposing spar caps include a thermoplastic fiber-reinforced outer frame comprising a base, perpendicular side walls extending from the base, and an open end opposite the base. Further, each of the spar caps includes a plurality of structural materials arranged within the outer frame, the structural materials including either or both of thermoplastic or thermoset plies or pultruded members. In addition, each of the spar caps includes a cured resin material that secures the plurality of structure materials within the outer frame. It should also be understood that the rotor blade may further include any of the additional features as described herein.

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:.

Thus, it is intended that the present invention include such modifications and variations as come within the scope of the appended claims and their equivalents.

Generally, the present disclosure is directed methods for manufacturing spar caps for wind turbine rotor blades. More specifically, in certain embodiments, the method includes forming an outer frame of the spar cap via at least one of 3D pultrusion or 3D printing. As such, the outer frame has a varying cross-section that corresponds to a varying cross-section of the rotor blade along a span thereof. The method also includes arranging a plurality of structural materials (e.g. layers of pultruded plates) within the outer frame of the spar cap and infusing the structural materials and the outer frame together via a resin material so as to form the spar cap. The resulting spar cap can then be easily incorporated into conventional rotor blade manufacturing processes and/or welded or bonded to an existing rotor blade.

Thus, the present subject matter provides numerous advantages not present in the prior art. For example, the present disclosure provides a method for manufacturing spar caps that does not require the use of conventional spar cap molds. As such, the present disclosure eliminates the need to transport pultruded plates to the spar cap mold which can be difficult. Moreover, the method of the present disclosure reduces the need for certain consumable materials.

Referring now to the drawings, <FIG> illustrates one embodiment of a wind turbine <NUM> according to the present disclosure. As shown, the wind turbine <NUM> includes a tower <NUM> with a nacelle <NUM> mounted thereon. A plurality of rotor blades <NUM> are mounted to a rotor hub <NUM>, which is in turn connected to a main flange that turns a main rotor shaft. The wind turbine power generation and control components are housed within the nacelle <NUM>. The view of <FIG> is provided for illustrative purposes only to place the present invention in an exemplary field of use. It should be appreciated that the invention is not limited to any particular type of wind turbine configuration. In addition, the present invention is not limited to use with wind turbines, but may be utilized in any application having rotor blades.

Referring now to <FIG> and <FIG>, various views of a rotor blade <NUM> according to the present disclosure are illustrated. As shown, the illustrated rotor blade <NUM> has a segmented or modular configuration. It should also be understood that the rotor blade <NUM> may include any other suitable configuration now known or later developed in the art. As shown, the modular rotor blade <NUM> includes a main blade structure <NUM> constructed, at least in part, from a thermoset and/or a thermoplastic material and at least one blade segment <NUM> configured with the main blade structure <NUM>. More specifically, as shown, the rotor blade <NUM> includes a plurality of blade segments <NUM>. The blade segment(s) <NUM> may also be constructed, at least in part, from a thermoset and/or a thermoplastic material.

The thermoplastic rotor blade components and/or materials as described herein generally encompass a plastic material or polymer that is reversible in nature. For example, thermoplastic materials typically become pliable or moldable when heated to a certain temperature and returns to a more rigid state upon cooling. Further, thermoplastic materials may include amorphous thermoplastic materials and/or semi-crystalline thermoplastic materials. For example, some amorphous thermoplastic materials may generally include, but are not limited to, styrenes, vinyls, cellulosics, polyesters, acrylics, polysulphones, and/or imides. More specifically, exemplary amorphous thermoplastic materials may include polystyrene, acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), glycolised polyethylene terephthalate (PET-G), polycarbonate, polyvinyl acetate, amorphous polyamide, polyvinyl chlorides (PVC), polyvinylidene chloride, polyurethane, or any other suitable amorphous thermoplastic material. In addition, exemplary semi-crystalline thermoplastic materials may generally include, but are not limited to polyolefins, polyamides, fluropolymer, ethyl-methyl acrylate, polyesters, polycarbonates, and/or acetals. More specifically, exemplary semi-crystalline thermoplastic materials may include polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene, polyphenyl sulfide, polyethylene, polyamide (nylon), polyetherketone, or any other suitable semi-crystalline thermoplastic material.

Further, the thermoset components and/or materials as described herein generally encompass a plastic material or polymer that is non-reversible in nature. For example, thermoset materials, once cured, cannot be easily remolded or returned to a liquid state. As such, after initial forming, thermoset materials are generally resistant to heat, corrosion, and/or creep. Example thermoset materials may generally include, but are not limited to, some polyesters, some polyurethanes, esters, epoxies, or any other suitable thermoset material.

In addition, as mentioned, the thermoplastic and/or the thermoset material as described herein may optionally be reinforced with a fiber material, including but not limited to glass fibers, carbon fibers, polymer fibers, ceramic fibers, nanofibers, wood fibers, bamboo fibers, metal fibers, or similar or combinations thereof. In addition, the direction of the fibers may include biaxial, unidirectional, triaxial, or any other another suitable direction and/or combinations thereof. Further, the fiber content may vary depending on the stiffness required in the corresponding blade component, the region or location of the blade component in the rotor blade <NUM>, and/or the desired weldability of the component.

More specifically, as shown, the main blade structure <NUM> may include any one of or a combination of the following: a pre-formed blade root section <NUM>, a pre-formed blade tip section <NUM>, one or more one or more continuous spar caps <NUM>, <NUM>, <NUM>, <NUM>, one or more shear webs <NUM> (<FIG>), an additional structural component <NUM> secured to the blade root section <NUM>, and/or any other suitable structural component of the rotor blade <NUM>. Further, the blade root section <NUM> is configured to be mounted or otherwise secured to the rotor <NUM> (<FIG>). In addition, as shown in <FIG>, the rotor blade <NUM> defines a span <NUM> that is equal to the total length between the blade root section <NUM> and the blade tip section <NUM>. As shown in <FIG> and <FIG>, the rotor blade <NUM> also defines a chord <NUM> that is equal to the total length between a leading edge <NUM> of the rotor blade <NUM> and a trailing edge <NUM> of the rotor blade <NUM>. As is generally understood, the chord <NUM> may generally vary in length with respect to the span <NUM> as the rotor blade <NUM> extends from the blade root section <NUM> to the blade tip section <NUM>.

Referring particularly to <FIG>, any number of blade segments <NUM> having any suitable size and/or shape may be generally arranged between the blade root section <NUM> and the blade tip section <NUM> along a longitudinal axis <NUM> in a generally span-wise direction. Thus, the blade segments <NUM> generally serve as the outer casing/covering of the rotor blade <NUM> and may define a substantially aerodynamic profile, such as by defining a symmetrical or cambered airfoil-shaped cross-section. In additional embodiments, it should be understood that the blade segment portion of the blade <NUM> may include any combination of the segments described herein and are not limited to the embodiment as depicted. In addition, the blade segments <NUM> may be constructed of any suitable materials, including but not limited to a thermoset material or a thermoplastic material optionally reinforced with one or more fiber materials. More specifically, in certain embodiments, the blade segments <NUM> may include any one of or combination of the following blade segments: pressure and/or suction side segments <NUM>, <NUM>, (<FIG> and <FIG>), leading and/or trailing edge segments <NUM>, <NUM> (<FIG>), a non-jointed segment, a single-jointed segment, a multi-jointed blade segment, a J-shaped blade segment, or similar.

More specifically, as shown in <FIG>, the leading edge segments <NUM> may have a forward pressure side surface <NUM> and a forward suction side surface <NUM>. Similarly, as shown in <FIG>, each of the trailing edge segments <NUM> may have an aft pressure side surface <NUM> and an aft suction side surface <NUM>. Thus, the forward pressure side surface <NUM> of the leading edge segment <NUM> and the aft pressure side surface <NUM> of the trailing edge segment <NUM> generally define a pressure side surface of the rotor blade <NUM>. Similarly, the forward suction side surface <NUM> of the leading edge segment <NUM> and the aft suction side surface <NUM> of the trailing edge segment <NUM> generally define a suction side surface of the rotor blade <NUM>. In addition, as particularly shown in <FIG>, the leading edge segment(s) <NUM> and the trailing edge segment(s) <NUM> may be joined at a pressure side seam <NUM> and a suction side seam <NUM>. For example, the blade segments <NUM>, <NUM> may be configured to overlap at the pressure side seam <NUM> and/or the suction side seam <NUM>. Further, as shown in <FIG>, adjacent blade segments <NUM>, <NUM> may be configured to overlap at a seam <NUM>. Thus, where the blade segments are constructed at least partially of a thermoplastic material, adjacent blade segments <NUM> can be welded together along the seams <NUM>, <NUM>, <NUM>, which will be discussed in more detail herein. Alternatively, in certain embodiments, the various segments of the rotor blade <NUM> may be secured together via an adhesive <NUM> (or mechanical fasteners) configured between the overlapping leading and trailing edge segments <NUM>, <NUM> and/or the overlapping adjacent leading or trailing edge segments <NUM>, <NUM>.

In specific embodiments, as shown in <FIG> and <FIG>, the blade root section <NUM> may include one or more longitudinally extending spar caps <NUM>, <NUM> infused therewith. For example, the blade root section <NUM> may be configured according to <CIT> entitled "Blade Root Section for a Modular Rotor Blade and Method of Manufacturing Same".

Similarly, the blade tip section <NUM> may include one or more longitudinally extending spar caps <NUM>, <NUM> infused therewith. More specifically, as shown, the spar caps <NUM>, <NUM>, <NUM>, <NUM> may be configured to be engaged against opposing inner surfaces of the blade segments <NUM> of the rotor blade <NUM>. Further, the blade root spar caps <NUM>, <NUM> may be configured to align with the blade tip spar caps <NUM>, <NUM>. Thus, the spar caps <NUM>, <NUM>, <NUM>, <NUM> may generally be designed to control the bending stresses and/or other loads acting on the rotor blade <NUM> in a generally span-wise direction (a direction parallel to the span <NUM> of the rotor blade <NUM>) during operation of a wind turbine <NUM>. In addition, the spar caps <NUM>, <NUM>, <NUM>, <NUM> may be designed to withstand the span-wise compression occurring during operation of the wind turbine <NUM>. Further, the spar cap(s) <NUM>, <NUM>, <NUM>, <NUM> may be configured to extend from the blade root section <NUM> to the blade tip section <NUM> or a portion thereof. Thus, in certain embodiments, the blade root section <NUM> and the blade tip section <NUM> may be joined together via their respective spar caps <NUM>, <NUM>, <NUM>, <NUM>.

In addition, the spar caps <NUM>, <NUM>, <NUM>, <NUM> may be constructed of any suitable materials, e.g. a thermoplastic or thermoset material or combinations thereof. Further, the spar caps <NUM>, <NUM>, <NUM>, <NUM> may be pultruded from thermoplastic or thermoset resins. As used herein, the terms "pultruded," "pultrusions," or similar generally encompass reinforced materials (e.g. fibers or woven or braided strands) that are impregnated with a resin and pulled through a stationary die such that the resin cures or undergoes polymerization. As such, the process of two-dimensional (2D) pultrusion is typically characterized by a continuous process of composite materials that produces composite parts having a constant cross-section. Thus, the pre-cured composite materials may include pultrusions constructed of reinforced thermoset or thermoplastic materials. Further, the spar caps <NUM>, <NUM>, <NUM>, <NUM> may be formed of the same pre-cured composites or different pre-cured composites. In addition, the pultruded components may be produced from rovings, which generally encompass long and narrow bundles of fibers that are not combined until joined by a cured resin.

Further, three-dimensional (3D) pultrusion is generally characterized by a manufacturing process similar to 2D pultrusion, but that can accommodate three-dimensional curved profiles. In addition, 3D pultrusion processes can be used to generate pultruded components having a variety of non-linear or variable cross-sectional shapes rather than a constant cross-section. Referring to <FIG>, one or more shear webs <NUM> may be configured between the one or more spar caps <NUM>, <NUM>, <NUM>, <NUM>. More particularly, the shear web(s) <NUM> may be configured to increase the rigidity in the blade root section <NUM> and/or the blade tip section <NUM>. Further, the shear web(s) <NUM> may be configured to close out the blade root section <NUM>.

In addition, as shown in <FIG> and <FIG>, the additional structural component <NUM> may be secured to the blade root section <NUM> and extend in a generally span-wise direction. For example, the structural component <NUM> may be configured according to <CIT> entitled "Structural Component for a Modular Rotor Blade". More specifically, the structural component <NUM> may extend any suitable distance between the blade root section <NUM> and the blade tip section <NUM>. Thus, the structural component <NUM> is configured to provide additional structural support for the rotor blade <NUM> as well as an optional mounting structure for the various blade segments <NUM> as described herein. For example, in certain embodiments, the structural component <NUM> may be secured to the blade root section <NUM> and may extend a predetermined span-wise distance such that the leading and/or trailing edge segments <NUM>, <NUM> can be mounted thereto.

Referring now to <FIG>, improved methods for manufacturing rotor blades and various components thereof, such as spar caps, are illustrated. More specifically, as shown in <FIG>, a flow diagram of one embodiment of a method <NUM> for manufacturing a spar cap (e.g. the spar caps <NUM>, <NUM>) of the rotor blade <NUM> of the wind turbine <NUM> is illustrated. As shown at <NUM>, the method <NUM> includes forming the outer frame <NUM> of the spar cap <NUM> via at least one of 3D pultrusion, thermoforming, or 3D printing. More specifically, in one embodiment, the step of pultruding the outer frame <NUM> of the spar cap <NUM> may include pultruding the outer frame <NUM> from a thermoplastic material reinforced with one or more fiber materials. In such embodiments, the fiber material(s) may include glass fibers, carbon fibers, metal fibers, polymer fibers, ceramic fibers, nanofibers, wood fibers, bamboo fibers, or combinations thereof. Thus, as shown in <FIG>, the outer frame <NUM> may be a thermoplastic fiber-reinforced component having a base <NUM>, perpendicular side walls <NUM> extending from the base <NUM>, and an open end <NUM> opposite the base <NUM>. In further embodiments, the outer frame <NUM> may have a varying cross-section that corresponds to a varying cross-section of the rotor blade <NUM> along the span <NUM> thereof. In additional embodiments, the base <NUM> may act as a layer of structural material, thereby reducing the number of layers of additional structural material <NUM> needed within the spar caps <NUM>, <NUM>, which is discussed in more detail below.

In another embodiment, the step of pultruding the outer frame <NUM> of the spar cap <NUM> may include pultruding extended side edges <NUM> of the outer frame <NUM>. For example, as shown in <FIG> and <FIG> (lower spar cap <NUM>), the extended side edges <NUM> may be configured as shear clips <NUM> for attaching to the shear web <NUM> of the rotor blade <NUM>. In addition, as shown in <FIG>, the extended side edges <NUM> may be used at attachment points for one or more straps <NUM> that can be attached to the outer frame <NUM> of the spar cap <NUM>. As such, the outer frame <NUM> of the spar cap <NUM> can be easily lifted and/or moved, e.g. via a crane <NUM>, during the manufacturing process. In such embodiments, a spacer <NUM> may be used in conjunction with the open end <NUM> of the outer frame <NUM> so as to prevent the side edges <NUM> from collapsing inward as the spar cap <NUM> is being lifted.

Alternatively, as shown in <FIG> (upper spar cap <NUM>), the method <NUM> may include folding the extended side edges <NUM> towards a center <NUM> of the outer frame <NUM> so as to retain the structural material(s) <NUM> therein, e.g. before the structural material(s) <NUM> are secured within the outer frame <NUM>. In still alternative embodiments, as shown in <FIG> (upper spar cap <NUM>), the method <NUM> may include folding the extended side edges <NUM> away from the center <NUM> of the outer frame <NUM> to create opposing flanges <NUM>. Thus, as shown, the method <NUM> may also include securing the flanges <NUM> to the pressure side surface <NUM> and/or the suction side surface <NUM> of the rotor blade <NUM>. In further embodiments, as shown in <FIG> (lower spar cap <NUM>), the method <NUM> may include removing the extended side edges <NUM> from the outer frame <NUM>.

Referring back to <FIG>, as shown at <NUM>, the method <NUM> also includes arranging a plurality of structural materials <NUM> within the pultruded outer frame <NUM> of the spar cap <NUM>. More specifically, the structural material(s) <NUM> may include thermoplastic or thermoset plies or pultruded members or plates. Further, as shown in <FIG> and <FIG>, the method <NUM> may include arranging a plurality of layers <NUM> of the structural materials <NUM> within the outer frame <NUM> of the spar cap <NUM> and arranging one or more non-structural layers <NUM> between the layers <NUM> of structural materials <NUM>. More specifically, in certain embodiments, the non-structural material(s) <NUM> may include a glass veil, a continuous fiber mat, or a fabric material (such as a light weight biaxial glass fabric). Thus, the non-structural layers <NUM> are configured to serve as process aids and joining media for various infusion processes by, e.g. promoting resin flow, wet out, and ultimately, resin connections between the structural layers <NUM>. Additionally, both non-pultruded structural layers and/or non-structural layers (essentially flexible conforming layers) can be used to help fill any gaps or voids between the stack of layers and the outer frame <NUM>.

Referring still to <FIG>, as shown at <NUM>, the method <NUM> includes infusing the structural materials <NUM> and the outer frame <NUM> together via a resin material <NUM> so as to form the spar cap <NUM>. More specifically, the structural material(s) <NUM> and the outer frame <NUM> may be infused together via injection molding, thermoforming, vacuum forming, or vacuum infusion. As such, the outer frame <NUM> is configured to maintain the structural material(s) <NUM> of the spar cap <NUM> in their desired location before then components are joined or infused together. Further, in one embodiment, the resin material <NUM> may include at least one of a thermoset material, a thermoplastic material, or similar, or combinations thereof. Thus, as shown at <NUM>, the method <NUM> may include allowing the spar cap <NUM> to cure.

In another embodiment, as shown in <FIG>, the side walls <NUM> of the outer frame <NUM> may include one or more features configured for increasing the flexibility thereof. As such, the outer frame <NUM> can be easily mounted to any of the blade surfaces. For example, as shown in <FIG>, the side walls <NUM> of the outer frame <NUM> include a plurality of perforated lines <NUM>. As such, the perforated lines <NUM> allow the side walls <NUM> to bend and flex with the curvature of a variety of blade surfaces. Alternatively, as shown in <FIG>, the side walls <NUM> of the outer frame <NUM> may include one or more slots <NUM> or gaps configured to increase flexibility thereof. Another advantage of providing the slots <NUM> or gaps in the side walls <NUM> includes allowing the resin material to more easily flow in and around the outer frame <NUM> when infusing the structural materials <NUM> therein.

Referring now to <FIG>, a flow diagram of another embodiment of a method <NUM> for manufacturing a spar cap of the rotor blade <NUM> of the wind turbine <NUM> is illustrated. As shown at <NUM>, the method <NUM> includes forming an outer frame of the spar cap (e.g. spar caps <NUM>, <NUM>). More specifically, in one embodiment, the step of forming the outer frame <NUM> of the spar cap <NUM> may include heating a thermoset or thermoplastic material and forming the material into a desired blade shape. Alternatively, the step of forming the outer frame <NUM> of the spar cap <NUM> may include forming the outer frame <NUM> of the spar cap <NUM> via at least one of 3D pultrusion, thermoforming, or 3D printing.

Further, as shown at <NUM>, the method <NUM> includes machining a plurality of structural materials <NUM>. More specifically, as used herein, the step of machining may include, but is not limited to cutting (e.g. laser-jet, water-jet), chamfering, surface preparing (e.g. chemical, mechanical, or other), scoring, cleaning, labeling, coating, or any other suitable machining process. Further, as mentioned, the structural material(s) <NUM> as described herein may include thermoplastic or thermoset plies or pultruded members. As shown at <NUM>, the method <NUM> includes dispensing the structural material(s) <NUM> directly into the outer frame <NUM> of the spar cap <NUM> after machining. Thus, in such embodiments, conventional spar cap molds can thereby be eliminated.

Referring still to <FIG>, as shown at <NUM>, the method <NUM> includes infusing the structural material(s) <NUM> and the outer frame <NUM> together via at least one of a thermoplastic or thermoset resin material so as to form the spar cap <NUM>. More specifically, as mentioned, the structural material(s) <NUM> and the outer frame <NUM> may be infused together via injection molding, thermoforming, vacuum forming, or vacuum infusion. In addition, as shown at <NUM>, the method <NUM> includes allowing the spar cap <NUM> to cure.

Referring now to <FIG>, a flow diagram of one embodiment of a method <NUM> for manufacturing a rotor blade <NUM> of a wind turbine <NUM> is illustrated. As shown at <NUM>, the method <NUM> includes forming the outer frame <NUM> of the spar cap <NUM> via at least one of 3D pultrusion, thermoforming, or 3D printing. As such, the outer frame <NUM> has a varying cross-section that corresponds to a varying cross-section of the rotor blade <NUM> along the span <NUM> thereof. As shown at <NUM>, the method <NUM> includes arranging a plurality of structural materials <NUM> (e.g. thermoplastic or thermoset plies or pultruded members or plates) within the pultruded outer frame <NUM> of the first spar cap <NUM>. As shown at <NUM>, the method <NUM> includes securing the structural material(s) <NUM> and the outer frame <NUM> together so as to form the first spar cap <NUM>.

Further, as shown at <NUM>, the method <NUM> includes joining the outer frame <NUM> of the first spar cap <NUM> to an inner surface of at least one of the pressure side surface <NUM> or the suction side surface <NUM> of the rotor blade <NUM>. More specifically, in one embodiment, the step of joining the outer frame <NUM> of the spar cap <NUM> to the inner surface of the pressure side surface <NUM> or the suction side surface <NUM> may include laying an outer skin layer of at least one of the pressure side surface <NUM> or the suction side surface <NUM> into a shell mold, placing the outer frame <NUM> of the spar cap <NUM> adjacent to the outer skin, laying an inner skin layer of at least one of the pressure side surface <NUM> or the suction side surface <NUM> atop the spar cap <NUM>, and infusing the spar cap <NUM> between the outer and inner skin layers. Alternatively, the outer frame <NUM> of the spar cap <NUM> may be joined to either of the pressure or suction side surfaces <NUM>, <NUM> via welding or bonding.

In another embodiment, as shown in <FIG>, the method <NUM> may include forming a second spar cap <NUM>, joining one of the first and second spar caps <NUM>, <NUM> to the pressure side surface <NUM> and the other of the first and second spar caps <NUM>, <NUM> to the suction side surface <NUM>, and securing the shear web <NUM> between the first and second spar caps <NUM>, <NUM>. More specifically, as shown, the method <NUM> may include securing the shear web(s) <NUM> to the extended side edges <NUM> of the outer frame(s) <NUM> of the spar caps <NUM>, <NUM>.

In further embodiments, as shown in <FIG>, the method <NUM> may include attaching one or more straps <NUM> to the extended side edges <NUM> of the outer frame <NUM> of the spar cap <NUM> (e.g. at one or more attachment locations <NUM>) and placing the spar cap <NUM>, e.g. via a lifting device <NUM> such as a crane, fork lift, or similar, into the shell mold via the straps <NUM>. Alternatively, the method <NUM> may include attaching one or more straps <NUM> around the outer frame <NUM> of the spar cap <NUM> (as indicated by the dotted line) and placing the spar cap <NUM> into the shell mold via the straps <NUM>.

Claim 1:
A method for manufacturing a rotor blade (<NUM>) of a wind turbine (<NUM>), the method comprising:
forming an outer frame (<NUM>) of a first spar cap (<NUM>, <NUM>) of the rotor blade (<NUM>) via at least one of three-dimensional (3D) pultrusion or 3D printing, the outer frame (<NUM>) having a varying cross-section that corresponds to a varying cross-section of the rotor blade (<NUM>) along a span (<NUM>) thereof;
arranging a plurality of structural materials (<NUM>) within the outer frame (<NUM>) of the first spar cap (<NUM>, <NUM>), the plurality of structural materials (<NUM>) comprising at least one of thermoplastic or thermoset plies or pultruded members;
securing the plurality of structural materials (<NUM>) and the outer frame (<NUM>) together so as to form the first spar cap (<NUM>, <NUM>); and,
joining the first spar cap (<NUM>, <NUM>) to an inner surface of at least one of a pressure side or a suction side of the rotor blade (<NUM>).