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 modem wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and a rotor having a rotatable hub with one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as 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.

The rotor blades generally include a suction side shell and a pressure side shell typically formed using molding processes that are bonded together at bond lines along the leading and trailing edges of the blade. Further, the pressure and suction shells are relatively lightweight and have 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. Thus, 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 pressure and suction side surfaces of the shell halves. The spar caps and/or shear web may be constructed of various materials, including but not limited to glass fiber laminate composites and/or carbon fiber laminate composites.

Various rotor blades may be divided into two or more segments and assembled to form a completed rotor blade. Each segment of a segmented rotor blade generally includes suction and pressure side shells and one or more structural components. Such segments and their respective components are typically assembled at joints between segments. Certain segmented rotor blades utilize one or more scarf connections to join the structural components of the segments.

For instance, a first blade segment may include a beam structure receivable into a receiving section of a second blade segment. Generally, the beam structure of the first blade segment typically tapers in order to fit within the receiving section of the second blade segment. However, the pressure and suction shells generally define a smooth transition between the first and second blade segments. As such, the tapered portion of the beam structure may create a gap between the beam structure and the inner pressure and/or suction side surfaces of the shell halves. In addition, certain materials used to form the beam structure (e.g., carbon fiber composites and/or carbon fiber pultrusions) may be relatively structurally stiff and therefore difficult to manipulate within the scarf joint, further contributing to the size of the gap. Such a gap may be undesirable as it may increase a bond dimension between the structural component and the respective shell halves, may increase the risk of delamination, may increase the cost of production of the turbine blade, and/or may necessitate undesirable repair procedures. Documents <CIT> and <CIT> are prior art examples of segmented wind turbine blades.

Accordingly, the present disclosure is directed to a beam structure for a segmented rotor blade having an improved rotor blade that includes a spacer material between the beam structure and the blade shell so as to address the aforementioned issues.

In one aspect, the present disclosure is directed to a rotor blade for a wind turbine. The rotor blade includes a first blade segment and a second blade segment extending in opposite directions from a chord-wise joint. Each of the first and second blade segments include one or more shell members and an internal support structure. The internal support structure of the first blade segment includes a beam structure extending between a first end at the chord-wise joint and a second end. The internal support structure of the second blade segment includes a receiving section that receives the beam structure of the first blade segment. Further, the beam structure and the receiving section are each coupled to an inner surface of the one or more shell members of the first blade segment and the second blade segment, respectively. Additionally, the rotor blade includes one or more spacer materials arranged within the first blade segment between an exterior surface of the beam structure and the inner surface of the one or more shell members. As such, the spacer material(s) reduces a bond gap between the exterior surface of the beam structure and the inner surface of the one or more shell members.

In another embodiment, the spacer material(s) may be adjacent to the first end of the beam structure and extends in a span-wise direction towards the second end. In one such embodiment, the spacer material(s) may extend from the chord-wise joint along the beam structure up to about <NUM>% of a length of the first blade segment. In a further embodiment, the spacer material(s) may substantially fill the bond gap between the exterior surface of the beam structure and the inner surface of the one or more shell members. In a further embodiment, the second blade segment may define a second bond gap between an exterior surface of the receiving section the inner surface of the one or more shell members. Moreover, the second bond gap may be less than the bond gap. In such an embodiment, the spacer material(s) may define a thickness of approximately a difference between the second bond gap and the first bond gap.

According to the invention, shell member(s) include a suction side shell member and a pressure side shell member. In such an embodiment, the beam structure of the first blade segment includes a suction side spar structure coupled to the inner surface of the suction side shell member and a pressure side spar structure coupled to the inner surface of the pressure side shell member. Moreover, in such an embodiment, the suction side and pressure side spar structures may taper from the first end to the second end. In one such embodiment, the one or more spacer materials may include a suction side spacer material arranged between an exterior surface of the suction side spar structure and the inner surface of the suction side shell member and a pressure side spacer material arranged between an exterior surface of the pressure side spar structure and the inner surface of the pressure side shell member. In a further embodiment, the spacer material(s) may be secured to the exterior surface of the beam structure and the inner surface of the pressure side shell member and/or the suction side shell member via an adhesive.

In one embodiment, the spacer material(s) may be constructed, at least in part, from at least one of a foam material, a wood material, a cork material, a fiber material, a composite material, or combinations thereof. In one exemplary embodiment, the beam structure may be constructed, at least in part, of a pultruded carbon composite material. According to the invention, at least one of the suction side spar structure or the pressure side spar structure includes a pultruded carbon composite material.

In yet another aspect, the present disclosure is directed to a method of joining a first blade segment of a rotor blade of a wind turbine to a second blade segment of the rotor blade of the wind turbine at a chord-wise joint. Each of the first and second rotor blade segments includes one or more shell members and an internal support structure. The method includes forming a beam structure of the internal support structure of the first blade segment. The method further includes forming a receiving section of the internal support structure of the second blade segment. Another step includes securing one or more spacer materials to an exterior surface of the beam structure and/or an inner surface of the shell member(s) of the first blade segment. The method also includes inserting the beam structure of the first blade segment into the receiving section of the second blade segment. As such, the one or more spacer materials reduce a bond gap between the exterior surface of the beam structure and the inner surface of the shell member(s). Additionally, the method includes securing the first and second blade segments together.

In one embodiment, the one or more shell members include a suction side shell member and a pressure side shell member. In such an embodiment, securing the one or more spacer materials to an exterior surface of the beam structure and/or an inner surface of the shell member(s) of the first blade segment may further include securing the spacer material(s) to the exterior surface of the beam structure and subsequently securing the beam structure to at the pressure side shell member and/or the suction side shell member of the first blade segment.

In another embodiment, securing the one or more spacer materials to an exterior surface of the beam structure and/or an inner surface of the shell member(s) of the first blade segment may further include securing the spacer material(s) to the pressure side shell member and/or the suction side shell member of the first blade segment and subsequently securing the beam structure to the one or more spacer materials.

In a still further embodiment, securing the one or more spacer materials to an exterior surface of the beam structure and/or an inner surface of the shell member(s) of the first blade segment may further include securing the spacer material(s) to an exterior surface of a pressure side spar structure and/or a suction side spar structure located on a pressure side and a suction side of the first blade segment, respectively. In one such embodiment, the one or more spacer materials may include a suction side spacer material and a pressure side spacer material. As such, the method may further include securing the suction side spacer material to an exterior surface of a suction side spar structure located on the suction side of the first blade segment and/or the inner surface of the suction side shell member of the first blade segment. Additionally, the method may include securing the pressure side spacer material to an exterior surface of a pressure side spar structure located on the pressure side of the first blade segment and/or the inner surface of the pressure side shell member of the first blade segment. It should be understood that the method may further include any of the additional features as described herein.

In a non-claimed embodiment, the present disclosure is directed to a rotor blade for a wind turbine. The wind turbine includes a first blade segment and a second blade segment extending in opposite directions from a chord-wise joint. Each of the first and second blade segments includes a pressure side shell member, a suction side shell member, and an internal support structure. The rotor blade further includes one or more spacer materials positioned adjacent to an inner surface of the pressure side or suction side shell member of the first blade segment and configured so as to provide a linear mounting surface. The internal support structure of the first blade segment includes a beam structure positioned adjacent to the linear mounting surface of the spacer material(s). Further, the internal support structure of the second blade segment includes a receiving section. As such, the beam structure is received within the receiving section so as to join the first and second blade segments together. It should be understood that the rotor blade may further include any of the additional features as described herein.

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 of the invention as defined by the appended claims.

Referring now to the drawings, <FIG> illustrates a perspective view of one embodiment of a wind turbine <NUM> according to the present invention. In the illustrated embodiment, the wind turbine <NUM> is a horizontal-axis wind turbine. In addition, as shown, the wind turbine <NUM> may include a tower <NUM> that extends from a support surface <NUM>, a nacelle <NUM> mounted on the tower <NUM>, a generator <NUM> positioned within the nacelle <NUM>, a gearbox <NUM> coupled to the generator <NUM>, and a rotor <NUM> that is rotationally coupled to the gearbox <NUM> with a rotor shaft <NUM>. Further, as shown, the rotor <NUM> includes a rotatable hub <NUM> and at least one rotor blade <NUM> coupled to and extending outward from the rotatable hub <NUM>. As shown, the rotor blade <NUM> includes a blade tip <NUM> and a blade root <NUM>.

Referring now to <FIG>, a plan view of one of the rotor blades <NUM> of <FIG> is illustrated. As shown, the rotor blade <NUM> may include a first blade segment <NUM> and a second blade segment <NUM>. Further, as shown, the first blade segment <NUM> and the second blade segment <NUM> may each extend in opposite directions from a chord-wise joint <NUM>. In addition, as shown, each of the blade segments <NUM>, <NUM> may include a one or more shell members and an internal support structure <NUM>. In certain embodiments, the one or more shell members may include a pressure side shell member <NUM> and a suction side shell member <NUM>. However, in other embodiments, one or both of the blade segments <NUM>, <NUM> may include one shell member with a pressure and suction side. As such, the pressure side shell member <NUM> and/or suction side shell member <NUM> described herein may be a pressure side or suction side of a single shell member, respectively. The first blade segment <NUM> and the second blade segment <NUM> may be connected by at least an internal beam structure <NUM> of the internal support structure <NUM> of the first blade segment <NUM> extending into both blade segments <NUM>, <NUM> to facilitate joining of the blade segments <NUM>, <NUM>. The arrow <NUM> shows that the segmented rotor blade <NUM> in the illustrated example includes two blade segments <NUM>, <NUM> and that these blade segments <NUM>, <NUM> are joined by inserting the internal beam structure <NUM> into the second blade segment <NUM>. For instance, the beam structure <NUM> of the first blade segment <NUM> may be inserted into the support structure <NUM> of the second blade segment <NUM>. In addition, as shown, the support structure <NUM> of the second blade segment <NUM> may extend lengthways for connecting with a blade root section <NUM> of the rotor blade <NUM> and with the beam structure <NUM> of the first blade segment <NUM> (which is shown in more detail in <FIG>).

Referring now to <FIG>, a perspective view of a section of the first blade segment <NUM> according to the present disclosure is illustrated. As shown, the first blade segment <NUM> may include the beam structure <NUM> that forms a portion of the support structure <NUM> of the first blade segment <NUM> and extends lengthways for structurally connecting with the second blade segment <NUM>. Further, as shown, the beam structure <NUM> may form a part of the first blade segment <NUM> having an extension (e.g., a joint portion <NUM>) protruding from an internal section <NUM>, thereby forming an extending spar section. In certain embodiments, the beam structure <NUM> may include one or more shear webs <NUM> connected with a suction side spar structure <NUM> (e.g., a suction side spar cap) and a pressure side spar structure <NUM> (e.g., a pressure side spar cap). Further, the beam structure <NUM> may be coupled to an inner surface <NUM> (see <FIG>) of the pressure side shell member <NUM> and/or the suction side shell member <NUM> of the first blade segment <NUM>. For instance, the pressure side spar structure <NUM> may be coupled to the inner surface <NUM> pressure side shell member <NUM> using an adhesive. Similarly, the suction side spar structure <NUM> may be coupled to the inner surface <NUM> of the suction side shell member <NUM> using an adhesive.

Moreover, as shown, the first blade segment <NUM> may include one or more first bolt joints towards a first end <NUM> of the beam structure <NUM>. In one embodiment, the bolt joint may include a pin that is in a tight interference fit with a bush. More specifically, as shown, the bolt joint(s) may include one bolt tube <NUM> located on the beam structure <NUM>. Thus, as shown, the bolt tube <NUM> may be oriented in a span-wise direction. Further, the first blade segment <NUM> may also include a bolt joint slot <NUM> located on the beam structure <NUM> proximate to the chord-wise joint <NUM>. Moreover, as shown, the bolt joint slot <NUM> may be oriented in a chord-wise direction. In one example, there may be a bushing within the bolt joint slot <NUM> arranged in a tight interference fit with a bolt tube or pin. Further, the first blade segment <NUM> may include multiple second bolt joint tubes <NUM>, <NUM> located at the chord-wise joint <NUM>. Thus, as shown, the second bolt joint tubes <NUM>, <NUM> may include a leading edge bolt joint tube <NUM> and a trailing edge bolt joint tube <NUM>. Further, each of the second bolt joint tubes <NUM>, <NUM> may be oriented in a span-wise direction. In addition, as shown, each of the second bolt joint tubes <NUM>, <NUM> may include multiple flanges <NUM>, <NUM>, respectively, that are configured to distribute compression loads at the chord-wise joint <NUM>.

It is to be noted that the bolt tube <NUM> located at the first end <NUM> of the beam structure <NUM> may be separated span-wise with the multiple second bolt joint tubes <NUM>, <NUM> located at the chord-wise joint <NUM> by an optimal distance D. This optimal distance D may be such that the chord-wise joint <NUM> is able to withstand substantial bending moments caused due to shear loads acting on the chord-wise joint <NUM>. In another embodiment, each of the bolt joints connecting the first and second blade segments <NUM>, <NUM> may include an interference-fit steel bushed joint.

Referring now to <FIG>, a perspective view of a section of the second blade segment <NUM> at the chord-wise joint <NUM> according to the present disclosure is illustrated. As shown, the second blade segment <NUM> includes a receiving section <NUM> extending lengthways within the second blade segment <NUM> for receiving the beam structure <NUM> of the first blade segment <NUM>. The receiving section <NUM> may include the support structure <NUM> including a pressure side spar structure <NUM> and a suction side spar structure <NUM> (e.g., opposing pressure and suction side spar caps) and one or more shear webs <NUM> extending therebetween. Further, the receiving section <NUM> may be coupled to an inner surface of the pressure side shell member <NUM> and/or the suction side shell member <NUM> of the second blade segment <NUM>. For instance, the pressure side spar structure <NUM> may be coupled to the inner surface of the pressure side shell member <NUM> using an adhesive. Similarly, the suction side spar structure <NUM> may be coupled to the inner surface of the suction side shell member <NUM> using an adhesive.

The receiving section <NUM> may extend lengthways for connecting with the beam structure <NUM> of the first blade segment <NUM>. For instance, the beam structure <NUM> may be inserted within the receiving section <NUM>. As shown, the second blade segment <NUM> may further include bolt joint slots <NUM>, <NUM> for receiving bolt tubes <NUM>, <NUM> (shown in <FIG>) of the first blade segment <NUM> and forming tight interference fittings. In one example, each of the multiple bolt joint slots <NUM>, <NUM> may include multiple flanges <NUM>, <NUM>, respectively, that are configured to distribute compression loads at the chord-wise joint <NUM>.

Referring now to <FIG>, an assembly <NUM> of the rotor blade <NUM> having the first blade segment <NUM> joined with the second blade segment <NUM> according to the present disclosure is illustrated. As shown, the assembly <NUM> illustrates multiple supporting structures beneath outer shell members of the rotor blade <NUM> having the first blade segment <NUM> joined with the second blade segment <NUM>. As further illustrated, the beam structure <NUM> may extend from the first end <NUM> at or approximately at the chord-wise joint <NUM> to a second end <NUM>. It should be appreciated that in certain embodiments (i.e., when the first blade segment <NUM> is a tip blade segment) the second end <NUM> may be positioned at or approximately at the blade tip <NUM> of the rotor blade <NUM>. Further, the spar structures <NUM>, <NUM> may be joined together at the second end <NUM> using any suitable adhesive material or an elastomeric seal. As shown, the beam structure <NUM> may be received within the receiving section <NUM> so as to join the first and second blade segments <NUM>, <NUM> together at the chord-wise joint <NUM>.

Further, as shown, the receiving section <NUM> may include the suction side spar structure <NUM> and the pressure side spar structure <NUM> extending lengthways and supporting the beam structure <NUM>. The receiving section <NUM> may also include a rectangular fastening element <NUM> that connects with the bolt tube <NUM> (see, e.g., <FIG>) of the beam structure <NUM> in the span-wise direction. Further, the first and the second blade segments <NUM>, <NUM> may also include chord-wise members <NUM>, <NUM> respectively at the chord-wise joint <NUM>. Further, as shown, the chord-wise members <NUM>, <NUM> may include leading edge bolt openings <NUM> and trailing edge bolt openings <NUM> that allows bolt joint connections between the first and second blade segments <NUM>, <NUM>. For example, as shown, the chord-wise members <NUM>, <NUM> are connected by bolt tubes <NUM> and <NUM> that are in tight interference fit with bushings located in the leading edge bolt openings <NUM> and the trailing edge bolt openings <NUM>. In another embodiment, each of the spar structures <NUM>, <NUM>, the rectangular fastening element <NUM>, and the chord-wise members <NUM>, <NUM> may be constructed of a composite material such as glass reinforced fibers or carbon reinforced fibers. In this example, the assembly <NUM> may also include multiple lightening receptor cables <NUM> that are embedded between the multiple bolt tubes or pins <NUM>, <NUM> and the bushing connections attached to the chord-wise members <NUM>, <NUM>.

In certain embodiments, at least a portion of the beam structure <NUM> may taper between the first end <NUM> and the second end <NUM>. For example, the internal section <NUM> of the beam structure <NUM> may taper between the chord-wise joint <NUM> and the second end <NUM>. More particularly, the pressure side spar structure <NUM>, the suction side spar structure <NUM>, or both may taper between the chord-wise joint <NUM> and the second end <NUM>. It should be appreciated that the beam structure <NUM> may taper in order to accommodate the taper of the first blade segment <NUM>. In one embodiment, the internal section <NUM> of the beam structure <NUM> may taper while the external section (e.g., the joint portion <NUM>) may define the same or approximately the same box beam section throughout the distance D, as shown in <FIG>. However, in other embodiments, the beam structure <NUM> may taper along the entire length between the first end <NUM> and the second end <NUM>.

Referring now to <FIG>, one embodiment of the chord-wise joint <NUM> of the first blade segment <NUM> is illustrated according to the present disclosure. More particularly, <FIG> illustrates a cross-section of the first blade segment <NUM> and the beam structure <NUM> along the span of the first blade segment <NUM>. As shown, the joint portion <NUM> may extend from the internal section <NUM> of the beam structure <NUM> such that the first blade segment <NUM> may be coupled to the second blade segment <NUM>. For instance, the joint portion <NUM> may be received by the receiving section <NUM>. It should be appreciated that the internal section <NUM> of beam structure <NUM> may be secured to the pressure side shell member <NUM> and/or the suction side shell member <NUM> as described in more detail below in regards to <FIG>. It should be appreciated that the beam structure <NUM> of <FIG> may generally be configured the same or similar to the beam structures <NUM> of <FIG>, and <FIG> and may generally be utilized in the rotor blades <NUM> of <FIG> and <FIG>. Though, in other embodiments, further configurations of the beam structure <NUM> are contemplated, such as different cross-sectional shapes and/or additional or fewer spar caps and/or shear webs. For instance, in one embodiment, two spar caps and a shear web may be in an I-beam configuration.

As shown in the exemplary embodiment of <FIG>, the rotor blade <NUM> may include one or more spacer materials <NUM> arranged within the first blade segment <NUM> between an exterior surface <NUM> of the beam structure <NUM> and an inner surface <NUM> of the pressure side shell member <NUM> and/or the suction side shell member <NUM>. Additionally, spacer material(s) <NUM> may be secured to the exterior surface <NUM> of the beam structure <NUM> and the inner surface <NUM> of the pressure side shell member <NUM> and/or the inner surface <NUM> of the suction side shell member <NUM> of the first blade segment <NUM>. For instance, the spacer material(s) <NUM> may be secured to the exterior surface <NUM> of the beam structure <NUM>, the inner surface(s) <NUM> of the pressure side shell member <NUM>, and/or the suction side shell member <NUM> via an adhesive material <NUM>. Moreover, the spacer material(s) <NUM> may be secured to both the exterior surface <NUM> of the beam structure <NUM> and the inner surface(s) <NUM> of the pressure side shell member <NUM> and/or the suction side shell member <NUM> using the adhesive material <NUM>. It should be appreciated that one adhesive material <NUM> is illustrated between the spacer material(s) <NUM> and the pressure side and/or suction side shell members <NUM>, <NUM> for clarity. However, adhesive material <NUM> may also be between the exterior surface <NUM> of the beam structure <NUM> and the spacer material(s) <NUM>. As such, the spacer material(s) <NUM> may reduce a bond gap <NUM> between the exterior surface <NUM> of the beam structure <NUM> and the inner surface <NUM> of one of the pressure side shell member <NUM> or the suction side shell member <NUM>.

In one embodiment, the spacer material(s) <NUM> may substantially fill the bond gap <NUM> between the exterior surface <NUM> of the beam structure <NUM> and the inner surface <NUM> of one of the pressure side shell member <NUM>, the suction side shell member <NUM>, or both. For example, the spacer material(s) <NUM> may fill the bond gap <NUM> other than the adhesive material <NUM> used to secure the spacer material(s) <NUM> to the exterior surface <NUM> of the beam structure <NUM> and the inner surface <NUM> of the pressure and/or suction side shell member <NUM>, <NUM>. It should be appreciated that the adhesive material may include a thermoset and/or a thermoplastic material.

As further illustrated in <FIG>, the second blade segment <NUM> may define a second bond gap <NUM> between an exterior surface <NUM> of the receiving section <NUM> the inner surface(s) <NUM> of the shell members <NUM>, <NUM>. Moreover, the second bond gap <NUM> may be less than the bond gap <NUM>. It should be appreciated that the relative size of the beam structure <NUM> and the receiving section <NUM> may lead to the size difference between the bond gap <NUM> and the second bond gap <NUM>. More particularly, a smaller beam structure <NUM> able to be inserted within the receiving section <NUM> may create a larger bond gap(s) <NUM> between the exterior surface <NUM> of the beam structure <NUM> and the inner surface <NUM> of the shell member(s) <NUM>, <NUM> as compared to the second bond gap <NUM>. In such an embodiment, the spacer material(s) <NUM> may define a thickness <NUM> of approximately a difference between the second bond gap <NUM> and the first bond <NUM> (such as a thickness <NUM> within <NUM>% of the difference between the second bond gap <NUM> and the bond gap <NUM>). As such, it should be appreciated that the spacer material(s) <NUM> may reduce the impact created by the difference in size between the beam structure <NUM> and the receiving section <NUM>. Though, in other embodiments, it should be appreciated that the spacer material(s) <NUM> may define a thickness <NUM> greater than such a difference. Such as any thickness up to approximately the bond gap <NUM>. In still further embodiments, the thickness <NUM> may be less than the difference between the second bond gap <NUM> and the bond gap <NUM>.

The spacer material(s) <NUM> may be adjacent to the first end <NUM> of the beam structure <NUM> and extend in a span-wise direction towards the second end <NUM> (see, e.g., <FIG> and <FIG>). For instance, the spacer material(s) <NUM> may be positioned near the chord-wise joint <NUM> and extend toward the second end <NUM>. As shown, the spacer material(s) <NUM> may be fully housed within the suction and pressure side shell members <NUM>, <NUM>. For example, the spacer material(s) <NUM> may be secured or coupled to the internal section <NUM> of the beam structure <NUM>. However, in other embodiments, the spacer material(s) <NUM> may extend partially from inside the first blade segment <NUM>. For instance, the spacer material(s) <NUM> may extend at least partially along the extending spar segment. In one embodiment, the spacer material(s) <NUM> may extend from the chord-wise joint <NUM> along the internal section <NUM> of the beam structure <NUM> up to about <NUM>% of a length of the first blade segment <NUM>. In another embodiment, the spacer material(s) <NUM> may extend from the chord-wise joint <NUM> along the beam structure <NUM> up to about <NUM>% of the length of the first blade segment <NUM>. Moreover, in certain embodiments, the spacer material(s) <NUM> may extend from the chord-wise joint <NUM> or approximately the chord-wise joint <NUM> (e.g., within about <NUM>% of the length of the beam structure <NUM> from the chord-wise joint <NUM>) to the second end <NUM>.

In certain embodiments, as illustrated in <FIG>, the one or more spacer materials <NUM> may include a suction side spacer material <NUM> arranged between the exterior surface <NUM> of the suction side spar structure <NUM> and the inner surface <NUM> of the suction side shell member <NUM> and a pressure side spacer material <NUM> arranged between the exterior surface <NUM> of the pressure side spar structure <NUM> and the inner surface <NUM> of the pressure side shell member <NUM>. It should be appreciated the suction side spacer material <NUM> and pressure side spacer material <NUM> may extend along substantially the same length of the beam structure <NUM> and may start at the substantially the same point adjacent to the first end <NUM> of the beam structure <NUM> (e.g., at or near the chord-wise joint <NUM>). However, in other embodiments, the suction side spacer material <NUM> and pressure side spacer material <NUM> may extend along different lengths of the beam structure <NUM> and/or may start at different positions adjacent to the first end <NUM> of the beam structure <NUM>. Further, in other embodiments, it should be appreciated that the first blade segment <NUM> may include one spacer material <NUM>, such as the pressure side spacer material <NUM> or the suction side spacer material <NUM>. In such embodiments, the side opposite the beam structure <NUM> may be directly coupled, e.g., bonded using an adhesive material, to the shell member <NUM>, <NUM> opposite the spacer material <NUM>.

It should be recognized that the spacer material(s) <NUM> may reduce the degree to which the spar structures <NUM>, <NUM> must be bent and/or contoured at the chord-wise joint <NUM>. For instance, the spacer material(s) <NUM> may reduce the degree the spar structures <NUM>, <NUM> must be bent in order to form the joint portion <NUM> operable with the receiving section <NUM>. Moreover, spar structures <NUM>, <NUM> made of certain materials, such as pultruded composites or pultruded carbon, may be difficult to bend at the chord-wise joint <NUM> without adding undesirable stress to the spar structures <NUM>, <NUM>. Further, the spacer material(s) <NUM> may reduce the amount of adhesive necessary to fill the bond gap <NUM> between the exterior surface <NUM> of the beam structure <NUM> and the inner surface(s) <NUM> of the pressure side shell member <NUM> and/or the suction side shell member <NUM>. As such, it should be appreciated that reducing the amount of adhesive necessary to fill the bond gap <NUM> may provide a better bond between the shell members <NUM>, <NUM> and the beam structure <NUM> and improve the structural properties of the rotor blade <NUM>.

It should also be appreciated that the spacer material(s) <NUM> may generally be contoured to the shape of the exterior surface <NUM> of the beam structure <NUM> and/or the inner surface(s) <NUM> of the pressure side shell member <NUM> and/or the suction side shell member <NUM>. For instance, the thickness <NUM> of the spacer material(s) <NUM> may generally change along the chord between the leading edge and trailing edge. Further, the thickness <NUM> of the spacer material(s) <NUM> may generally change along the span between the chord-wise joint <NUM> and end of the spacer material(s) <NUM>.

Referring now to <FIG>, a further embodiment of the first blade segment <NUM> is illustrated according to the present subject matter. Particularly, <FIG> illustrates a cross-section of a partially assembled first blade segment <NUM>. As shown, the rotor blade <NUM> may include the spacer material(s) <NUM> positioned adjacent to the inner surface <NUM> of the pressure side and/or suction side shell member <NUM>, <NUM> of the first blade segment <NUM> and configured so as to provide one or more linear mounting surfaces <NUM>. The beam structure <NUM> of the first blade segment <NUM> may be positioned adjacent to the linear mounting surface(s) <NUM> of the spacer material(s) <NUM>, as shown generally by arrows <NUM>. It should be appreciated that the first blade segment <NUM> and beam structure <NUM> of <FIG> may generally be configured the same or similar to the first blade segments <NUM> and beam structures <NUM> of <FIG>, <FIG>, and <FIG> and may generally be utilized in the rotor blades <NUM> of <FIG> and <FIG>. Though, in other embodiments, further configurations of the first blade segment <NUM> and/or the beam structure <NUM> are contemplated.

Additionally, the spacer material(s) <NUM> may be secured (e.g., by use of the adhesive material) to the pressure side shell member <NUM> and/or the suction side shell member <NUM> of the first blade segment <NUM>. Further, the exterior surface <NUM> of the beam structure <NUM> may be subsequently secured to the spacer material(s) <NUM>, e.g., the linear mounting surface(s) <NUM> provided by the spacer material(s) <NUM>. For instance, in one embodiment, a suction side spacer material <NUM> may be secured to the suction side shell member <NUM>. Subsequently, the exterior surface <NUM> of the beam structure <NUM> (e.g., the exterior surface <NUM> of the suction side spar structure <NUM>) may be secured to the suction side spacer material <NUM>. Additionally, the pressure side spacer material <NUM> may be secured to the pressure side shell member <NUM>. Subsequently, the exterior surface <NUM> of the beam structure <NUM> (e.g., the exterior surface <NUM> of the pressure side spar structure <NUM>) may be secured to the pressure side spacer material <NUM>.

Referring now to <FIG>, another embodiment of the first blade segment <NUM> is illustrated according to the present subject matter. Particularly, <FIG> illustrates a cross-section of a partially assembled first blade segment <NUM>. As illustrated, the rotor blade <NUM> may include the spacer material(s) <NUM> positioned adjacent to the exterior surface <NUM> of the beam structure <NUM> of the first blade segment <NUM> so as to provide the linear mounting surface(s) <NUM>. Further, the internal surface(s) <NUM> of the pressure side shell member <NUM> and/or suction side shell member <NUM> may positioned adjacent to the linear mounting surface(s) <NUM> of the spacer material(s) <NUM>, as shown generally by arrows <NUM>. It should be appreciated that the first blade segment <NUM> and beam structure <NUM> of <FIG> may generally be configured the same or similar to the first blade segments <NUM> and beam structures <NUM> of <FIG>, <FIG>, and <FIG> and may generally be utilized in the rotor blades <NUM> of <FIG> and <FIG>. Though, in other embodiments, further configurations of the first blade segment <NUM> and/or the beam structure <NUM> are contemplated.

Additionally, the spacer material(s) <NUM> may be secured to the exterior surface <NUM> of a pressure side spar structure <NUM> and/or suction side spar structure <NUM> located on a pressure side and a suction side of the first blade segment <NUM>, respectively. Further, the inner surface(s) <NUM> of the pressure side shell member <NUM> and/or the suction side shell member <NUM> may be subsequently secured to the spacer material(s) <NUM>, e.g., the linear mounting surface(s) <NUM> provided by the spacer material(s) <NUM>.

It should be appreciated that forming the first blade segment <NUM> as shown in <FIG> may allow the final bond between the spacer material(s) <NUM> and the pressure and/or suction side shell members <NUM>, <NUM> to be examined using non-destructive testing techniques. For instance, ultrasonic testing may be utilized to ensure a strong final bond is formed between the spacer material(s) <NUM> and the pressure and/or suction side shell members <NUM>, <NUM>. Contrarily, securing the spacer material(s) <NUM> to the pressure and/or suction side shell members <NUM>, <NUM> and then subsequently to the beam structure <NUM> may make such examination more difficult. More particularly, certain non-destructive testing techniques, such as ultrasonic testing, may have difficulty penetrating certain types of materials (e.g., spacer material(s) <NUM> made of foam). As such, in the arrangement of <FIG>, only the initial bond between the spacer material(s) <NUM> and the pressure and/or suction side shell members <NUM>, <NUM> may be examined using ultrasonic testing while the final bond between the spacer material(s) <NUM> and the beam structure <NUM> may be obscured by the spacer material(s) <NUM>. It should be appreciated that the ability to examine the final bond (e.g., using non-destructive testing techniques) may be critical as such a bond may generally be inaccessible after the first blade segment <NUM> is assembled.

Referring still to <FIG>, in one embodiment, the one or more spacer materials <NUM> may include the suction side spacer material <NUM> and the pressure side spacer material <NUM>. As such, the suction side spacer material <NUM> may be secured (e.g., via an adhesive material) to the exterior surface <NUM> of a suction side spar structure <NUM> located on a suction side of the first blade segment <NUM>. Subsequently, the inner surface <NUM> of the suction side shell member <NUM> may be secured to the suction side spacer material <NUM>, such as to the linear mounting surface <NUM>. Additionally, the pressure side spacer material <NUM> may be secured (e.g., via an adhesive material) to the exterior surface <NUM> of the pressure side spar structure <NUM> located on the pressure side of the first blade segment <NUM>. Subsequently, the inner surface <NUM> of the pressure side shell member <NUM> may be secured to the pressure side spacer material <NUM>, such as to the linear mounting surface <NUM>.

It should be appreciated that the linear mounting surface(s) <NUM> near the chord-wise joint <NUM> and/or along the internal section <NUM> of the beam structure <NUM> may reduce the amount of the adhesive material needed to bond the internal support structure <NUM> to the pressure side shell member <NUM> and/or the suction side shell member <NUM>. Additionally, or alternatively, the linear mounting surface(s) <NUM> may reduce the degree to which the beam structure <NUM> must be bent near the chord-wise joint <NUM> in order to be received within the receiving section <NUM> of the second blade segment <NUM>. For instance, in at least one embodiment, the exterior surface <NUM> of the beam structure <NUM> oriented toward the pressure and/or suction side of the first blade segment <NUM> may be linear or substantially linear near the chord-wise joint <NUM>. Further, it should be recognized that the pressure and/or suction side spar structures <NUM>, <NUM> may be made of rigid materials (e.g., pultruded composite material and/or pultruded carbon materials) that are not easily pliable and thus difficult to bend or contour into a smaller cross-section able to be inserted within the receiving section <NUM> of the second blade segment <NUM>.

In one embodiment, the spacer material(s) <NUM> may be constructed, at least in part, from at least one of a foam material, a wood material, a cork material, a fiber material, a composite material, a polymer material or combinations thereof. In certain embodiments, the spacer material(s) <NUM> may be at least partially compressible in order to accommodate the strain on the shell member(s) <NUM>, <NUM> and/or the beam structure <NUM>. For instance, in one embodiment, the spacer material(s) may elastically deform or approximately elastically deform up to at least <NUM> microstrain, such as up to at least <NUM> microstrain, or, more particularly, up to at least <NUM> microstrain. In one exemplary embodiment, the beam structure <NUM> may be constructed, at least in part, of a pultruded carbon and/or pultruded composite material. For instance, at least one of the suction side spar structure <NUM> or the pressure side spar structure <NUM> may include a pultruded carbon composite material. Further, the pressure side shell member <NUM>, pressure side spacer material <NUM>, pressure side spar structure <NUM>, suction side spar structure <NUM>, suction side spacer material <NUM>, and/or suction side shell member <NUM> may generally be formed, at least in part, from biax composite plies and/or unidirectional composite plies including one or more fibers. In such embodiments, the fiber material(s) may include glass fibers, carbon fibers, polymer fibers, wood fibers, bamboo fibers, ceramic fibers, nanofibers, metal fibers, or combinations thereof. In addition, the direction or orientation of the fibers may include quasi-isotropic, multiaxial, unidirectional, biaxial, triaxial, or any other another suitable direction and/or combinations thereof.

In further embodiments, the shell member(s) <NUM>, <NUM>, spacer material(s) <NUM>, support structure(s) <NUM>, adhesive materials, and/or any part or combination of the preceding may include a thermoset resin or a thermoplastic resin. The thermoplastic materials as described herein may 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 materials as described herein may 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.

Referring now to <FIG>, a flow chart <NUM> of a method of joining a first blade segment of a rotor blade of a wind turbine to a second blade segment of the rotor blade of the wind turbine at a chord-wise joint is depicted according to the present disclosure. In general, the method <NUM> will be described herein with reference to the first and second blade segments <NUM>, <NUM> and beam structures <NUM> shown in <FIG>. However, it should be appreciated that the disclosed method <NUM> may be implemented with a segmented rotor blade <NUM> having any other configuration. In addition, although <FIG> depicts steps performed in a particular order for purposes of illustration and discussion, the methods discussed herein are not limited to any particular order or arrangement. One skilled in the art, using the disclosures provided herein, will appreciate that various steps of the methods disclosed herein can be omitted, rearranged, combined, and/or adapted in various ways without deviating from the scope of the present disclosure.

The method <NUM> may include (<NUM>) forming a beam structure of the internal support structure of the first blade segment. The method <NUM> may further include (<NUM>) forming a receiving section of the internal support structure of the second blade segment. Another step may include securing one or more spacer materials to an exterior surface of the beam structure and/or an inner surface of the shell member(s) of the first blade segment. For instance, as shown at (<NUM>), the method <NUM> may include securing one or more spacer materials to an exterior surface of the beam structure, an inner surface of the pressure side shell member of the first blade segment, and/or an inner surface of the suction side shell member of the first blade segment. In one embodiment, securing the one or more spacer materials <NUM> to an exterior surface <NUM> of the beam structure <NUM>, an inner surface <NUM> of the pressure side shell member <NUM> of the first blade segment <NUM>, and/or an inner surface <NUM> of the suction side shell member <NUM> of the first blade segment <NUM> may further include securing the spacer material(s) <NUM> to the exterior surface <NUM> of the beam structure <NUM> and subsequently securing the beam structure <NUM> to the pressure side shell member <NUM> and/or the suction side shell member <NUM> of the first blade segment <NUM>, as shown particularly in <FIG>.

In another embodiment, securing the one or more spacer materials <NUM> to an exterior surface <NUM> of the beam structure <NUM>, an inner surface <NUM> of the pressure side shell member <NUM> of the first blade segment <NUM>, and/or an inner surface <NUM> of the suction side shell member <NUM> of the first blade segment <NUM> may further may include securing the spacer material(s) <NUM> to the pressure side shell member <NUM> and/or the suction side shell member <NUM> of the first blade segment <NUM> and subsequently securing the beam structure <NUM> to the spacer material(s) <NUM>.

In a still further embodiment, securing the one or more spacer materials <NUM> to an exterior surface <NUM> of the beam structure <NUM>, an inner surface <NUM> of the pressure side shell member <NUM> of the first blade segment <NUM>, and/or an inner surface <NUM> of the suction side shell member <NUM> of the first blade segment <NUM> may further include securing the spacer material(s) <NUM> to an exterior surface <NUM> of a pressure side spar structure <NUM> and/or a suction side spar structure <NUM> located on a pressure side and a suction side of the first blade segment <NUM>, respectively. In one such embodiment, the one or more spacer materials <NUM> may include a suction side spacer material <NUM> and a pressure side spacer material <NUM>. As such, the method <NUM> may further include securing the suction side spacer material <NUM> to the exterior surface <NUM> of the suction side spar structure <NUM> located on a suction side of the first blade segment <NUM> and/or the inner surface <NUM> of the suction side shell member <NUM> of the first blade segment <NUM>. Additionally, the method <NUM> may include securing the pressure side spacer material <NUM> to the exterior surface <NUM> of a pressure side spar structure <NUM> located on a pressure side of the first blade segment <NUM> and/or the inner surface <NUM> of the pressure side shell member <NUM> of the first blade segment <NUM>.

The method may also include (<NUM>) inserting the beam structure of the first blade segment into the receiving section of the second blade segment. As such, the at least one spacer material <NUM> may reduce a bond gap <NUM> between the exterior surface <NUM> of the beam structure <NUM> and the inner surface <NUM> of shell member(s). For instance, the spacer material(s) <NUM> may reduce a bond gap <NUM> between the exterior surface <NUM> of the beam structure <NUM> and the inner surface <NUM> of one of the pressure side shell member <NUM> or the suction side shell member <NUM>. Additionally, the method <NUM> may include <NUM> securing the first and second blade segments <NUM>, <NUM> together, as described and shown generally in regards to <FIG>.

Claim 1:
A rotor blade (<NUM>) for a wind turbine (<NUM>), comprising:
a first blade segment (<NUM>) and a second blade segment (<NUM>) extending in opposite directions from a chord-wise joint (<NUM>), each of the first and second blade segments (<NUM>, <NUM>) comprising one or more shell members (<NUM>, <NUM>) and an internal support structure (<NUM>), the internal support structure (<NUM>) of the first blade segment (<NUM>) comprising a beam structure (<NUM>) extending between a first end (<NUM>) at the chord-wise joint (<NUM>) and a second end (<NUM>), wherein the beam structure (<NUM>) comprises a suction side spar structure (<NUM>) and a pressure side spar structure (<NUM>), the internal support structure (<NUM>) of the second blade segment (<NUM>) comprising a receiving section (<NUM>) that receives the beam structure (<NUM>) of the first blade segment (<NUM>), the beam structure (<NUM>) and the receiving section (<NUM>) coupled to an inner surface (<NUM>) of the one or more shell members (<NUM>, <NUM>) of the first blade segment (<NUM>) and the second blade segment (<NUM>), respectively; characterized in that at least one of the suction side spar structure (<NUM>) and the pressure side spar structure (<NUM>) comprises a pultruded carbon composite material and,
at least one spacer material (<NUM>) arranged within the first blade segment (<NUM>) between an exterior surface (<NUM>) of the beam structure (<NUM>) and the inner surface (<NUM>) of the one or more shell members (<NUM>, <NUM>) so as to reduce a bond gap (<NUM>) between the exterior surface (<NUM>) of the beam structure (<NUM>) and the inner surface (<NUM>) of the one or more shell members (<NUM>, <NUM>).