EP4735757A1

EP4735757A1 - Resonating structure for wind turbine blades

Info

Publication number: EP4735757A1
Application number: EP24740339.7A
Authority: EP
Inventors: Alf SØE-KNUDSEN; Mranal GUPTA
Original assignee: Vestas Wind Systems AS
Current assignee: Vestas Wind Systems AS
Priority date: 2023-06-30
Filing date: 2024-06-26
Publication date: 2026-05-06
Also published as: CN121399368A; WO2025002522A1

Abstract

A wind turbine blade (20) that extends longitudinally in a spanwise direction between a root end (24) and a tip end (26), and in a chordwise direction between a leading edge (28) and a trailing edge (30), is disclosed. The wind turbine blade (20) includes a first opposing half-shell portion (34) and a second opposing half-shell portion (36) which together define an interior (38) the wind turbine blade (20), and at least one shear web (52) that extends between the first opposing half-shell portion (34) and the second opposing half-shell portion (36). The wind turbine blade (20) further includes at least one vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) for reducing noise emission from the wind turbine blade (20). The at least one vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) includes at least one resonating member (62, 138, 202, 232, 260) that extends from a surface of the wind turbine blade (20) to a distal end (70, 96, 156, 186, 206, 234, 262) that is configured to oscillate to dissipate vibrational energy away from the surface of the wind turbine blade (20).

Description

RESONATING STRUCTURE FOR WIND TURBINE BLADES

Technical Field

This application relates generally to wind turbines, and more particularly to a system and method for damping vibrations of wind turbine blades to reduce the acoustic noise generated by wind turbine blades during operation of a wind turbine.

Background

Wind turbines are used to produce electrical energy using a renewable resource and without combusting a fossil fuel. Generally, a wind turbine converts kinetic energy from the wind into electrical power. A horizontal-axis wind turbine includes a tower, a nacelle located at the apex of the tower, and a rotor having a plurality of blades and supported in the nacelle by means of a shaft. The shaft couples the rotor either directly or indirectly with a generator, which is housed inside the nacelle. Consequently, as wind forces the blades to rotate the rotor, electrical energy is produced by the generator. To this end, wind turbines may be located either on a land mass (onshore) or within a body of water (offshore).

As the demand for renewable energy sources has increased in recent years, the number of wind turbines installed worldwide has also grown significantly. Moreover, wind turbines have been developed in larger sizes to generate more electricity to meet the ever-growing demand for electrical energy. However, as wind turbines become more prevalent, one of the challenges associated with wind turbines is the generation of acoustic noise during their operation, which can cause disturbances for nearby residents. The blades are one component of the wind turbine that can generate acoustic noise during operation.

Wind turbine blades, while designed to be aerodynamical ly efficient, can experience various forms of vibration during operation. These vibrations can be caused by factors such as turbulence, unsteady wind conditions, and mechanical interactions within the wind turbine structure. For example, during the operation of the wind turbine, vibrations can be generated by mechanical equipment within the nacelle, such as the gearbox, generator, and other equipment necessary for power generation. These vibrations can propagate from the nacelle and through the structure of the blades, contributing to the overall vibrational energy traveling along the length of the blades. As the vibrational energy travels along the length of the blade, it radiates into the surrounding air as sound waves, resulting in noise emissions.

Conventional approaches to mitigate the acoustic noise generated by wind turbine blades include reducing the overall aerodynamic noise of the turbine blade. These approaches may include modifying the blade design, optimizing the rotational speed, or applying noise-reducing coatings. Other approaches include targeting the source of the vibrational energy traveling through the blade, such as by utilizing vibration mounts with the mechanical equipment within the nacelle, for example. While these approaches have demonstrated certain effectiveness, there is still a need to specifically address the issue of vibrational energy traveling along wind turbine blades and subsequently radiating as acoustic noise.

Summary

According to a first aspect of the invention, a wind turbine blade that extends longitudinally in a spanwise direction between a root end and a tip end, and extends in a chordwise direction between a leading edge and a trailing edge is disclosed. The wind turbine blade includes a first opposing half-shell portion and a second opposing half-shell portion which together define an interior of the wind turbine blade, and at least one shear web that extends between the first opposing half-shell portion and the second opposing half-shell. The wind turbine blade further includes at least one vibration damping device to reduce the noise emission from the wind turbine blade. In that regard, the at least one vibration damping device includes at least one resonating member that extends from a surface of the wind turbine blade to a distal end that is configured to oscillate to dissipate vibrational energy away from the surface of the wind turbine blade. A wind turbine including the wind turbine blade is also disclosed.

The at least one resonating member extends from the surface of the wind turbine blade to a distal end of the resonating member.

According to one embodiment of the invention, the at least one vibration damping device may be located within the interior of the wind turbine blade such that the surface that the at least one vibration damping device extends from may be an interior surface of the wind turbine blade. For example, the interior surface may be on the at least one shear web. Alternatively, the interior surface may be on the first opposing half-shell portion or the second opposing half-shell.

According to another embodiment of the invention, the at least one resonating member may include a core and an outer skin. For instance, the core may include a resilient core material and a mass positioned adjacent to the distal end of the at least one resonating member.

In yet another embodiment of the invention, the at least one vibration damping device may include at least a first vibration damping device and a second vibration damping device spaced apart and separately attached to the interior surface of the wind turbine blade. In that regard, the first vibration damping device and the second vibration damping device may be configured to dissipate different bands of vibrational energy frequencies. In yet another embodiment, the first vibration damping device and the second vibration damping device may extend in parallel.

In one embodiment of the invention, the at least one resonating member may be an elongate fin that extends a length along the interior surface of the wind turbine blade in the spanwise direction. In another embodiment, the at least one resonating member may include a height measured between a first end attached to the interior surface of the wind turbine blade and the distal end and a thickness measured between a first side surface and a second side surface. The height of the at least one resonating member may be greater than the thickness. Furthermore, the first side surface and the second side surface of the at least one resonating member may be substantially planar between the first end attached to the interior surface of the wind turbine blade and the distal end. In one embodiment, the at least one resonating member may be wavy in transverse cross-section. In yet another embodiment, the height of the at least one resonating member may vary along a length of the at least one resonating member.

Preferably, the length of the resonating member is equal to or greater than the height of the resonating member. In this way this way the elongate fin and can dissipate vibrational energy more effectively. For example, the length may be at least 2 times the height, or at least 3 times, or at least 5 times, or at least 10 times the height. A more elongate fin may dissipate vibrational energy more effectively.

Preferably, the resonating member is attached to the interior surface of the wind turbine blade for the full extent of its length, or substantially its full length, e.g. greater than 50%, 60%, 70%, 80%, 90% or 95% of if length. In this way, the resonating member can effectively function as a vibration absorber and dissipate vibrational energy.

According to one embodiment of the invention, the at least one vibration damping device may be located on an exterior of the wind turbine blade such that the surface that the at least one resonating member extends from may be an exterior surface of the wind turbine blade. For example, the exterior surface may be on the first opposing half-shell portion or the second opposing half-shell portion.

In one embodiment, the at least one damping device may be located at the root end of the wind turbine blade. In yet another embodiment, the at least one resonating member may include a plurality of resonating members connected together at a base of the at least one damping device. In that regard, the plurality of resonating members may extend circumferentially about the root end of the wind turbine blade to form an annular ring of resonating members. Furthermore, the plurality of resonating members may be bridged together at each distal end to form a plurality of resonating units. According to one embodiment of the invention, the at least one vibration damping device may be located in the first one-third of the length of the wind turbine blade measured from the root end.

Brief Description of the Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention. Fig. 1 is a perspective view of a wind turbine according to an embodiment of the invention.

Fig. 2 is a perspective view of a wind turbine blade of the wind turbine of Fig. 1 .

Fig. 3 is a cross-sectional view through the wind turbine blade shown in Fig. 2, generally along line 3-3.

Fig. 4 is a cross-sectional view through the wind turbine blade shown in Fig. 2, generally along line 4-4.

Fig 5A is a cross-sectional view of a portion of the wind turbine blade of Figs. 1-4, illustrating a vibration damping device attached to a shear web in accordance with an embodiment of the invention.

Fig. 5B is a cross-sectional view a portion of the wind turbine blade of Figs. 1-4, illustrating a vibration damping device attached to a shear web in accordance with an embodiment of the invention.

Fig. 5C is a cross-sectional view of a portion of the wind turbine blade of Figs. 1-4, illustrating a plurality of vibration damping devices attached to a shear web in accordance with an embodiment of the invention.

Fig. 6A is a perspective view of a portion of a shear web of the wind turbine blade of Figs. 1-4, illustrating a vibration damping device with a flattened profile in accordance with an embodiment of the invention.

Fig. 6B is a perspective view of a portion of a shear web of the wind turbine blade of Figs. 1-4, illustrating a vibration damping device with a tapered profile in accordance with an embodiment of the invention.

Fig. 6C is a perspective view of a portion of a shear web of the wind turbine blade of Figs. 1-4, illustrating at least two vibration damping devices arranged in series and each having a tapered profile in accordance with an embodiment of the invention. Fig. 6D is a perspective view of a portion of a shear web of the wind turbine blade of Figs. 1 -4, illustrating a vibration damping device with a wavy distal end in accordance with an embodiment of the invention.

Fig. 6E is a perspective view of a portion of a shear web of the wind turbine blade of Figs. 1 -4, illustrating a vibration damping device with a wavy profile in accordance with an embodiment of the invention.

Fig. 6F is a perspective view of a portion of a shear web of the wind turbine blade of Figs. 1-4, illustrating a vibration damping device with a wavy profile and a wavy distal end in accordance with an embodiment of the invention.

Fig 7A is a cross-sectional view of a portion of the wind turbine blade of Figs. 1 -4, illustrating at least one vibration damping device attached an interior surface of the wind turbine blade in accordance with an embodiment of the invention.

Fig 7B is a cross-sectional view of the wind turbine blade of Figs. 1 -4, illustrating a plurality of vibration damping devices attached to an interior surface of a first half-shell portion and a second half-shell portion the wind turbine blade in accordance with an embodiment of the invention.

Fig. 8A is a perspective view of a section of the wind turbine blade shown in Fig. 2, illustrating a plurality of vibration damping devices attached to interior surfaces of the wind turbine blade in accordance with an embodiment of the invention.

Fig. 8B is a perspective view of an exemplary vibration damping device in accordance with an embodiment of the invention.

Fig. 8C is a perspective view of a section of the wind turbine blade shown in Fig. 2, illustrating a plurality of vibration damping devices attached to surfaces of the shear webs of the wind turbine blade in accordance with an embodiment of the invention. Fig. 8D is a perspective view of a vibration damping module including a plurality of vibration damping devices in accordance with an embodiment of the invention.

Fig. 8E is a perspective view of a vibration damping module including a plurality of vibration damping devices in accordance with another embodiment of the invention.

Fig. 9A is a perspective view of a modular resonating segment in accordance with an embodiment of the invention.

Fig. 9B is a side view of the modular resonating segment of Fig. 9A.

Fig. 9C illustrates a process for assembling plurality of modular resonating segment together to form a vibration damping device in accordance with an embodiment of the invention.

Fig. 9D is a side view of the vibration damping device that is being assembled in Fig. 9C.

Fig. 10A is a perspective view of a modular resonating segment in accordance with an embodiment of the invention.

Fig. 10B is a side view of the modular resonating segment of Fig. 10A.

Fig. 10C illustrates a process for assembling plurality of modular resonating segment together to form a vibration damping device in accordance with an embodiment of the invention.

Fig. 10D is a side view of the vibration damping device that is being assembled in Fig. 10C.

Fig. 11A is a perspective view of a section of the wind turbine blade shown in Fig. 2, illustrating a plurality of the vibration damping devices of Figs. 9D and 10D attached to interior surfaces of the wind turbine blade in accordance with an embodiment of the invention. Fig. 11 B is a perspective view of an exemplary vibration damping device in accordance with an embodiment of the invention.

Fig. 11 C is a perspective view of a section of the wind turbine blade shown in Fig. 2, illustrating a plurality of the vibration damping devices of Fig. 9D attached to surfaces of the shear webs of the wind turbine blade in accordance with an embodiment of the invention.

Fig. 12A is a partial cross-sectional view of the root end of the wind turbine blade shown in Fig. 2, illustrating an annular vibration damping device attached to interior surfaces of the wind turbine blade in accordance with an embodiment of the invention.

Fig. 12B is a perspective view of the root end of the wind turbine blade shown in Fig. 2, illustrating a plurality of annular vibration damping devices attached to interior surfaces of the root end of the wind turbine blade.

Fig. 12C is a perspective view of the root end of the wind turbine blade shown in Fig. 2, illustrating a plurality of annular vibration damping devices attached to interior surfaces of the root end of the wind turbine blade in accordance with another embodiment of the invention.

Fig. 12D is a perspective view of the root end of the wind turbine blade shown in Fig. 2, illustrating a plurality of annular vibration damping devices attached to interior surfaces of the root end of the wind turbine blade in accordance with another embodiment of the invention.

Fig. 12E is a perspective view of the root end of the wind turbine blade shown in Fig. 2, illustrating a single annular vibration damping device attached to the interior surface of the root end of the wind turbine blade in accordance with another embodiment of the invention.

Fig. 12F is a perspective view of the root end of the wind turbine blade shown in Fig. 2, illustrating a plurality of semi-circle-shaped vibration damping devices attached to interior surfaces of the root end of the wind turbine blade in accordance with another embodiment of the invention.

Fig. 12G is a perspective view of the root end of the wind turbine blade shown in Fig. 2, illustrating a plurality of annular vibration damping devices attached to exterior surfaces of the root end of the wind turbine blade.

Fig. 12H is a partial cross-sectional view of the root end of the wind turbine blade shown in Fig. 2, illustrating an annular vibration damping device attached to interior surfaces of the wind turbine blade in accordance with an embodiment of the invention.

Fig. 121 is a partial cross-sectional view of the root end of the wind turbine blade shown in Fig. 2, illustrating an annular vibration damping device attached to interior surfaces of the wind turbine blade in accordance with an embodiment of the invention.

Fig. 13A is a side view of a modular resonating segment in accordance with an embodiment of the invention.

Fig. 13B is a side view of a modular resonating segment in accordance with another embodiment of the invention.

Fig. 14A is a partial cross-sectional view of the root end of the wind turbine blade shown in Fig. 2, illustrating an annular vibration damping device attached to interior surfaces of the wind turbine blade, the vibration damping device being formed of a plurality of modular resonating segment of Fig. 13A in accordance with an embodiment of the invention.

Fig. 14B is a partial cross-sectional view of the root end of the wind turbine blade shown in Fig. 2, illustrating an annular vibration damping device attached to interior surfaces of the wind turbine blade, the vibration damping device being formed of a plurality of modular resonating segment of Fig. 13B in accordance with an embodiment of the invention. Fig. 15A is a partial cross-sectional view of the root end of the wind turbine blade shown in Fig. 2, illustrating an annular vibration damping device attached to interior surfaces of the wind turbine blade in accordance with an embodiment of the invention.

Fig. 15B is a partial cross-sectional view of the root end of the wind turbine blade shown in Fig. 2, illustrating an annular vibration damping device attached to interior surfaces of the wind turbine blade in accordance with an embodiment of the invention.

Detailed Description

With reference to Figs. 1 through 15B, embodiments of a vibration damping device for reducing noise emission from a wind turbine, and in particular from a wind turbine blade, are shown. In that regard, during the operation of a wind turbine, vibrations may be generated by mechanical equipment within the nacelle of the wind turbine, such as the gearbox, generator, and other equipment necessary for power generation, for example. The energy from these vibrations is eventually transferred to the nacelle structure. From the nacelle structure, these vibrations can propagate into the structure of the attached wind turbine blades, traveling along their lengths from the root end to the tip end. In particular, vibrations from different mechanical equipment can accumulate a group velocity of vibrational energy and thereby result in a resonating behavior at particular frequencies as they travel along the length of the blade. The group velocity of the vibrations depends on various factors, including the material properties of the blades, their structural characteristics, and the frequency of the vibrations. To this end, the vibrational energy radiates from the blades as sound in the form of acoustic waves. In some cases, the vibrations can reach resonance, meaning they match the natural frequency of the blade structure, leading to increased vibrational amplitudes and thus noise emission from the blade.

To reduce the vibrational energy radiating from the blade as sound in the form of acoustic waves, one or more vibration damping devices in accordance with embodiments of the invention may be attached to the blade. The one or more vibration damping devices are configured to disrupt the group velocity of the propagating vibrations. In particular, the vibration damping devices effectively break the group velocity of the propagating vibrations by absorbing and dissipating a significant portion of their energy away from surfaces of the wind turbine blade. By breaking the group velocity and reducing the vibrational energy, the vibration damping devices attenuate the transmission of vibrations along the blade. Consequently, the amount of vibrational energy that radiates from the blade as sound in the form of acoustic waves (i.e. , noise) is significantly reduced. These and other benefits of the present invention will be described more fully below.

Turning with reference to Fig. 1 , an exemplary wind turbine 10 is shown which includes a tower 12, a nacelle 14 disposed at the apex of the tower 12, and a rotor 16 operatively coupled to a generator (not shown) housed inside the nacelle 14, and a gearbox (not shown) housed inside the nacelle 14. In addition to the generator and gearbox, the nacelle 14 may house various components needed to convert wind energy into electrical energy and to operate and optimize the performance of the wind turbine 10. The tower 12 supports the load presented by the nacelle 14, rotor 16, and other wind turbine components housed inside the nacelle 14, or external to the nacelle 14, and operates to elevate the nacelle 14 and the rotor 16 to a height above ground level or sea level, as may be the case, at which air currents having lower turbulence and higher velocity are typically found.

The rotor 16 includes a central hub 18 and a plurality of wind turbine blades 20 (“blades”) attached to the central hub 18 at locations distributed about the circumference of the central hub 18. In the representative embodiment, the rotor 16 includes three blades 20, however the number of blades 20 may vary. The blades 20, which project radially outward from the central hub 18, are configured to interact with passing air currents to produce rotational forces that cause the central hub 18 to spin about its longitudinal axis 22. The design, construction, and operation of the blades 20 are familiar to a person having ordinary skill in the art of wind turbine design and may include additional functional aspects to optimize performance.

The rotor 16 may be coupled to the gearbox directly or indirectly by a drive shaft (not shown) to form a rotor assembly. Either way, the gearbox transfers the rotation of the rotor 16 through a coupling (not shown) to the generator. Wind exceeding a minimum speed may activate the rotor 16, causing the rotor 16 to rotate in a direction substantially perpendicular to the wind, and applying torque to the input shaft of the generator. The electrical power produced by the generator may be supplied to a power grid (not shown) or an energy storage system (not shown) for later release to the grid as understood by a person having ordinary skill in the art. In this way, the kinetic energy of the wind may be harnessed by the wind turbine 10 for power generation.

Fig. 2 is a schematic perspective view of an exemplary wind turbine blade 20. The blade 20 extends longitudinally in a spanwise direction S between a root end 24 and a tip end 26, and transversely in a chordwise C direction between a leading edge 28 and a trailing edge 30. The blade 20 includes an outer shell 32 which may be divided into a first (e.g., windward) half-shell portion 34 and a second (leeward) half-shell portion 36. The outer shell 32 may be moulded from glass-fiber reinforced plastic (GRP), for example. The first half-shell portion 34 and the second half-shell portion 36 may be formed as separate pieces that are joined together along the leading edge 28 and trailing edge 30 to form the outer shell 32 of the blade 20. Alternatively, the outer shell 32 of the blade 20 may be formed as a single piece without any glue joints. In either case, the first half shell portion 34 and the second half shell portion 36 of the outer shell 32 define a generally hollow interior 38 of the wind turbine blade 20. As best shown in Figs. 3-4, parts of the outer shell 32 are of a sandwich panel construction which may include a blade core 40 of lightweight foam (e.g., polyurethane) sandwiched between inner and outer GRP layers or skins 42, 44, respectively. To this end, the inner layer 42 may form an interior surface of the wind turbine blade 20 and the outer layer 44 may form an exterior surface of the wind turbine blade 20.

Referring now to Figs. 2-4, to increase strength and rigidity, the blade 20 further includes at least one spar structure 46 that extends longitudinally, in a spanwise S direction, along at least a portion of the length of the blade 20 between the root end 24 and the tip end 26. In the embodiment shown, the blade 20 includes two spar structures 46. However, it will be understood that the blade 20 may have fewer or more spar structures 46. Each spar structure 46 includes a pair of spar caps 48, 50 associated with respective first and second half-shell portions 34, 36 and a shear web 52 that extends between a corresponding pair of opposed spar caps 48, 50. In the embodiment shown, the blade 20 includes two spar structures 46 and thus two shear webs 52, which may be referred to as a main shear web and a trailing edge shear web. To this end, each shear web 52 and associated pair of spar caps 48, 50 may generally extend from the root end 24 of the blade 20 (e.g., Fig. 3) through the midsection of the blade 20 (e.g., Fig. 4) and generally to the tip end 26 of the blade 20.

The spar caps 48, 50 are generally designed to carry bending loads on the blade 20 and each shear web 52 is designed to generally carry the shear loads on the blade 20. In one embodiment, the spar caps 48, 50 may be integrated within the first and second half-shell portions 34, 36 such that the spar caps 48, 50 form part of the outer shell 32. Such an arrangement is illustrated in Figs. 3 and 4, for example. In an alternative embodiment (not shown), however, the spar caps 48, 50 may be separate elements adhesively bonded to the inner surface 42 of the outer shell 32. In one embodiment, the spar caps 48, 50 may be formed from a stack of pultruded fiber- reinforced composite strips. In an alternative embodiment, however, the spar caps 48, 50 may have a laminate composite construction of a plurality of fiber layers, resin, and possibly core material.

Each shear web 52 extends longitudinally in the spanwise S direction within the interior 38 of the wind turbine blade 20 and extends across the height of the blade 20 from the first half-shell portion 34 to the second half-shell portion 36 and between respective spar caps 48, 50. In an exemplary embodiment, each shear web 52 includes a lower flange 54, an upper flange 56, and an intermediate web structure 58 extending between the lower and upper flanges 54, 56. The lower and upper flanges 54, 56 of each shear web 52 are configured to be adhesively bonded to the inner layer 42 of the outer shell 32 of the blade 20. In another embodiment, the lower and upper flanges 54, 56 of each shear web 52 may be adhesively bonded to surfaces of the spar caps 48, 50 respectively. Each shear web 52 may be generally shaped as an I-beam. However, it should be understood by a person of ordinary skill in the art that the shear webs 52 may have different configurations, and the drawings are not intended to be limiting in this regard.

Turning now with reference to Figs. 5A and 6A, a vibration damping device 60 for damping vibrations to reduce noise emission from the wind turbine blade 20 is shown in accordance with a first embodiment of the invention. As shown, the vibration damping device 60 may be positioned within the interior 38 of the blade 20 and attached to an interior surface of the blade 20, and specifically one of the shear webs 52, such as the trailing edge shear web 52, for example. However, while the vibration damping device 60 is shown and described with respect to one particular shear web 52, it will be understood that the vibration damping device 60 may be attached to any one of the shear webs 52 of the blade 20, for example. As shown, the vibration damping device 60 may be attached to the web structure 58 of the shear web 52, generally at a midpoint therealong between the lower flange 54 and the upper flange 56. As shown in Fig. 6A, the vibration damping device 60 may extend a length longitudinally in the spanwise S direction along the shear web 52. To that end, the vibration damping device 60 may span the entire length of the shear web 52 or only a portion of the length of the shear web 52.

With continued reference to Figs. 5A and 6A, the vibration damping device 60 may be defined by at least one elongate resonating member 62. As shown in Fig. 6A, the resonating member 62 may include a flattened rectangular profile and extends in the spanwise S direction between a first end 64 and a second end 66 to define a length L of the resonating member 62. As shown in Fig. 5A, the resonating member 62 extends in the chordwise C direction between an attachment end 68 and a distal end 70 to define a height H of the resonating member 62. The resonating member 62 further includes a thickness T measured between a first side surface 72 and an opposite second side surface 74 of the resonating member 62. In that regard, the resonating member 62 exhibits a thin and flat profile, similar to a fin. This is due to the fact that the thickness T of the resonating member 62 is significantly smaller when compared to its height H. The resulting shape is a thin, flexible fin-shaped or strip-shaped resonating member 62 configured to oscillate to dissipate vibrational energy. In the embodiment shown, the first side surface 72 and the opposite second side surface 74 may be substantially planar. Similarly, the attachment end 68 and the distal end 70 of the resonating member 62 may be also substantially planar. As a result, the resonating member 62 may be generally rectangular in transverse (i.e., chordwise C) cross- sectional shape, as shown in Fig. 5A. However, the resonating member 62 may include other chordwise C transverse cross-sectional shapes as will be described in further detail below.

As best shown in Fig. 5A, the resonating member 62 extends generally perpendicularly from an internal facing surface 76 of the web structure 58 to which the resonating member 62 is attached. The attachment end 68 of the resonating member 62 may be adhesively bonded to the surface 76 of the web structure 58, for example. The attachment end 68 of the resonating member 62 is configured to be attached to the web structure 58 such that the resonating member 62 extends from the surface 76 of the web structure 58 to the distal end 70. That is, the attachment end 68 of the resonating member 62 may be affixed to the web structure 58 while the distal end 70 of the resonating member 62 remains free and unsupported. The resonating member 62 protrudes outward from the surface 76 of the web structure 58, resembling a cantilever beam setup. Depending on which side of the shear web 52 that the vibrational damping device 60 is positioned, the resonating member 62 may extend from the web structure 58 in a chordwise C direction toward the leading edge 28 or the trailing edge 30 of the blade 20.

With continued reference to Fig. 5A, the resonating member 62 may include a core 78 formed of a resilient core material and an outer skin 80. The core 78 may be formed of fiber-reinforced composite material or homogeneous materials such as thermoplastics, foams, metals, or combinations of such depending on the in situ desired vibrational behavior. For example, the at least one resonating member 62 may be formed of one or more pre-cured pultruded fibrous composite strips. The outer skin 80 may be a layer of GRP, for example. As shown, the outer skin 80 may extend about the first side surface 72, the second side surface 74, and the distal end 70 of the resonating member 62. The core 78 material at the attachment end 68 of the resonating member 62 may remain uncovered and exposed to facilitate direct attachment of the resonating member 62 to surfaces of the wind turbine blade 20. However, the outer skin 80 may completely cover the core material 78, leaving no part of the core 78 material exposed. In another embodiment, the resonating member 62 may not include the outer skin 80.

The core material 78 may be resilient to provide the resonating member 62 of the vibration damping device 60 with the ability to oscillate at a predetermined target frequency range to dissipate vibrational energy that travels along the length of the blade 20 in a direction away from the surface 76 of the wind turbine blade 20 to which it is attached. In particular, vibrational energy is absorbed by the attachment end 68 of the resonating member 62 and dissipated as the vibrational energy travels toward the distal end 70. The resonating member 62 effectively functions as a vibration absorber or energy sink that is configured to absorb vibrational energy into its structure. By attaching the resonating member 62 to the shear web 52, for example, which is a structural component of the wind turbine blade 20, the resonating member 62 is permitted to interact with the vibrations propagating along the length of the blade 20. The interaction of the resonating member 62 effectively disrupts the transmission of the vibrational energy traveling from the root end 26 to the tip end 28 of the blade 20, thereby mitigating the acoustic effects. In other words, the resonating member 62 dynamically absorbs and dissipates a significant amount of the vibrational energy through its oscillatory movements, minimizing noise emission from the wind turbine blade 20. To this end, as the resonating member 62 absorbs the vibrational energy from the blade structure 20, the distal end 70 of the resonating member 62 moves in relation to the attachment end 68 to effectively dissipate the vibrational energy absorbed by the resonating member 62 in the form of heat.

Strategic placement of one or more vibration damping devices 60 at resonant points along structure of the wind turbine blade 20, such as the shear web 52, further enhances the performance of the resonating member 62. In that regard, resonant points are locations on structures of the blade 20 where the vibrations traveling along the blade 20 exhibit maximum amplitude. By positioning the vibration damping device 60 at these critical points, the resonating member 62 may target the highest-energy regions of the vibrations. With respect to the shear web 52, resonant points may generally be located between the flanges 54, 56, such as at a middle third of the web structure 58 between the flanges 54, 56. However, the precise locations of resonant points can vary depending on the specific design and configuration of the wind turbine blade 20 and the shear web 52. Numerical simulations, experimental modal analysis, or structural dynamic analyses may be performed to identify and characterize these resonant points to locate the vibration damping device 60. Furthermore, the height H, thickness T, and length L of the resonating member 62, as well as the core material 78 of the resonating member 62, may be varied to modify the vibrational or oscillatory behavior of the resonating member 62 to target a specific frequency range of vibrations desired to be dampened. The frequency range for vibrations traveling along a wind turbine blade 20 may be within a range of between 50 Hz to 500 Hz, for example. Moreover, as the energy from mechanical vibrations is typically transferred from the nacelle 14 structure into the structure of the attached wind turbine blades 20 at the root end 24, it can be particularly effective to locate the at least one vibration damping device 60 in the first half of the length of the wind turbine blade 20 measured from the root end 24, and even more preferably in the first one-third of the length of the wind turbine blade 20 measured from the root end 24.

Fig. 5B illustrates the vibration damping device 60 in accordance with another embodiment of the invention. Like the embodiment described above with respect to Figs. 5A and 6A, the resonating member 62 extends generally perpendicularly from the surface 76 of the web structure 58 to which the resonating member 62 is attached. In particular, the attachment end 68 of the resonating member 62 may be directly and adhesively bonded to the surface 76 of the web structure 58, for example. However, to strengthen the attachment of the resonating member 62 to surfaces of the blade 20, such as the surface 76 of the web structure 58, a pair of L- shaped joint members 82 may be used. As shown, each joint member 82 is installed over a contact edge between the attachment end 68 of the resonant member 62 and the surface 76 to which it is attached. In the embodiment shown, one joint member 82 covers the contact edge between the first side surface 72 of the resonating member 62 and the surface 76 of the web structure 58. The second joint member 72 covers the contact edge between the second side surface 74 of the resonating member 62 and the surface 76 of the web structure 58. To this end, the joint members 82 may be adhered to surfaces 76 of the web structure 82 and the first and second side surfaces 72, 74 of the resonating member 62. The joint members 82 may be formed of composite materials such as fiberglass or carbon fiber fabric, for example. These materials may be impregnated with resin and applied over the contact edges, as described above, providing both structural reinforcement and a protective outer layer for the resonating member 62.

With continued reference to Fig. 5B, the resonating member 62 may further include a mass 84 positioned adjacent to the distal end 70. The mass 84 may be a concentration of core material 78 or formed of a material different from the core material 78. In that regard, the mass 84 includes a density that may be different from the core material 78. As shown, the mass 84 may be covered by the outer skin 80. However, the mass 84 may be exposed or uncovered by the outer skin 80. The mass 84 may be elongate or rod-shaped and extend continuously for the entire length of the resonating member 62. However, the mass 84 may be segmented or only extend for a portion of the length of the resonating member 62. The mass 84 enhances the ability of the resonating member 62 to dampen vibrations by altering the dynamic response characteristics of the resonating member 62. Specifically, the addition of the mass 84 at the distal end 70 of the resonating member 62 affects the overall mass distribution and moment of inertia of the resonating member 62, resulting in changes to its natural frequencies and damping properties. By increasing the mass at the free, distal end 70 of the resonating member 62, the natural frequencies of the resonating member 62 can be shifted, potentially allowing for better alignment with the target frequency range of the vibrations of the blade 20 that are desired to be dampened. This alignment enables the resonating member 62 to resonate more strongly with the incoming vibrations, thereby increasing its effectiveness in absorbing and dissipating the vibrational energy.

As mentioned above, one or more vibration damping devices 60 may be attached to interior surfaces of the wind turbine blade 20. Fig. 5C illustrates an exemplary embodiment where a plurality of vibration damping devices 60 may be separately attached to the shear web 52 at different locations along the web structure 58. The vibration damping devices 60 may be attached with or without joint members 82, for example. As shown, three vibration damping devices 60 may be attached to the web structure 58. However, fewer or more vibration damping devices 60 may be attached to the web structure 58 and at different locations along the web structure 58 or the shear web 52 generally. In either case, the resonating member 62 of each of the plurality of vibration damping devices 60 may extend in parallel to one another, and may extend in parallel with components of the spar structure 46, such as the spar caps 48, 50, for example. The resonating member 62 of each damping device 60 may be configured to dissipate the same bands of vibrational energy frequencies, or different bands of vibrational energy frequencies. In that regard, the resonating members 62 may be of similar size and configuration, or different. In the exemplary embodiment shown in Fig. 5C, each of the resonating members 62 has a different height H, and one resonating member 62 includes a mass 84 while the other two resonating members 62 do not include a mass 84. To this end, the number of vibration damping devices 60, the height H, thickness T, and length L of the resonating member 62, as well as the core material 78 of the resonating member 62 and/or the inclusion of a mass 84, may be varied to modify the vibrational or oscillatory behavior of the vibration damping device 60 to target certain frequency ranges of the vibrations intended to be dampened.

Turning now with reference to Figs. 6A-6F, different embodiments of the resonating member 62 of the vibration damping device 60 will now be described. As described above with respect to Fig. 6A, the resonating member 62 may have a generally flattened, rectangular profile. That is, the first side surface 72 and the opposite second side surface 74 may be substantially planar and the attachment end 68 and the distal end 70 of the resonating member 62 may be also substantially planar. However, other configurations of the resonating member 62 are possible. For example, the distal end 70 of the resonating member 62 may be tapered. As shown in Fig. 6B, the distal end 70 may gradually taper along the length L of the resonating member 62 from the first end 64 to the second end 66, resulting in the height H of the resonating member 62 being greater at the second end 66 compared to the first end 64.

As shown in Fig. 6C, a plurality of vibration damping devices 60 may be arranged in series to extend along a length of the wind turbine blade 20, and in particular a length of the shear web 52. That is, rather than extending continuously along the length of the wind turbine blade 20 and the shear web 52, the shear web 52 may include a plurality of vibration damping devices 60 arranged end-to-end along the length of the wind turbine blade 20 and the shear web 52. As shown in Fig. 6C, the resonating member 62 of each vibration damping device 60 may be tapered to define a uniform taper along the length of the wind turbine blade 20. However, each resonating member 62 of the vibration damping devices 60 in series may have a same or different configuration.

Fig. 6D illustrates the vibration damping device 60 in accordance with an embodiment where the height H of the resonating member 62 varies along the length L of the resonating member 62. That is, the distal end 70 of the resonating member 62 may be wavy, jagged, or otherwise non-planar to the attachment end 68 of the resonating member 62. Similarly, Fig. 6E illustrates the vibration damping device 60 in accordance with another embodiment where the resonating member 62 is wavy in transverse (i.e., spanwise S) cross-sectional shape. That is, the location of the attachment end 68 along a height of the web structure 58 of the shear web 52 varies along the length L of the resonating member 62. Fig. 6F illustrates the vibration damping device 60 in accordance with another embodiment where the height H of the resonating member 62 varies along the length L of the resonating member 62 and the resonating member 62 is wavy in transverse (i.e., spanwise S) cross- sectional shape. Additionally, or alternatively, the resonating member 62 may be wavy (e.g., S-shaped) in chordwise C transverse cross-sectional shape.

One or more vibration damping devices 60 may be attached to interior and/or exterior surfaces of the wind turbine blade 20. The interior or exterior surfaces may be on the first opposing half-shell portion 34 or the second opposing half-shell portion 36. Fig. 7A illustrates vibration damping devices 60 positioned within the interior 38 of the blade 20 and attached to an interior surface of the blade 20, and specifically to the inner layer 42 of the outer shell 32 of the wind turbine blade 20. In particular, the resonating member 62 of each vibration damping device 60 may be attached to the inner layer 42 of the first half-shell portion 34. However, one or more vibration damping devices 60 may be attached to the first half-shell portion 34 or the second half-shell portion 36, or both. As shown in Fig. 7B, one or more vibration damping devices 60 may be attached to the inner layer 42 of each of the first halfshell portion 34 and the second half-shell portion 36 of the outer shell 32 of the blade 20. For instance, one or more one or more vibration damping devices 60 may be attached to the inner layer 42 at locations therealong between the trailing edge 30 and the trailing edge shear web 52, between the trailing edge shear web 52 and the main shear web 52, and/or between the main shear web 52 and the leading edge 28, or any combination thereof.

Turning now with reference to Figs. 8A-8E, a vibration damping device 90 is shown in accordance with another embodiment of the invention. In that regard, like reference numerals represent like features compared to the embodiment of the vibration damping device 60 described above with respect to Figs. 1-7B. The primary difference between the vibration damping device 90 of this embodiment and the vibration damping device 60 of the previously described embodiment is that the vibration damping device 90 includes a plurality of resonating members 62 connected together to form a plurality of resonating units 92. In particular, the plurality of resonating members 62 may be spaced apart along a common base member 94 to which the attachment end 68 of each resonating member 62 is joined or integrated. The distal end 70 of each resonating member 62 may be joined or integrated with a common top member 96. In that regard, the resonating members 62, the top member 96, and base member 94 may be formed together as a unitary piece that is the vibration damping device 90. The construction of each member 62, 94, 96 may be similar to the construction of the resonating member 62 described above with respect to Figs. 1-7B. For example, the vibration damping device 90 may be formed of fiber-reinforced composite material or homogeneous materials, and may be formed via extrusion or pultrusion manufacturing methods.

As shown in Figs. 8A and 8B, each of the plurality of resonating units 92 defines an open-ended void or passageway 98 that extends through the vibration damping device 90. Thus, the vibration damping device 90 may be considered an open-cell device, with the voids 98 being open to the surrounding environment, such as the interior 38 of the wind turbine blade 20. In particular, each resonating unit 92 may be generally box-shaped, and includes two resonating members 62 bridged or joined together at their distal ends 70 by the top member 96 and at their attachment ends 68 by the base member 94. As shown, the vibration damping device 90 includes a width W between a first end 100 and a second end 102 and a length L that corresponds to the length L of each resonating member 62. The width W of each vibration damping device 90 may be in terms of resonating units 92, for example. In that regard, the vibration damping device 90 may be one, two, three, four, or more resonating units 92 in width W. The vibration damping device 90 may be elongate in the widthwise W direction. That is, the width W of the vibration damping device 90 may be greater than the length L of the vibration damping device 90.

One or more vibration damping devices 90 may be attached to interior surfaces of the wind turbine blade 20, as shown in Fig. 8A. In that regard, the base member 94 of each vibration damping device 90 may be adhesively bonded to the inner layer 42 of the outer shell 32 of the blade 20. As shown, one or more one or more vibration damping devices 90 may be attached to the inner layer 42 at locations therealong between the trailing edge 30 and the trailing edge shear web 52, between the trailing edge shear web 52 and the main shear web 52, and/or between the main shear web 52 and the leading edge 28, or any combination thereof. To this end, the vibration damping devices 90 may be arranged on the inner layer 42 of the first half-shell portion 34 or the second half-shell portion 36, or both. As shown in Fig. 8A, the vibration damping devices 90 may be arranged in parallel strips that are spaced apart in the spanwise S direction along the length of the wind turbine blade 20. To that end, each vibration damping device 90 may be arranged such that the width W of the vibration damping device 90 extends in the chordwise C direction of the wind turbine blade 20.

Depending on the size constraints of the interior 38 of the wind turbine blade 20, the width W of each vibration damping device 90 may be varied. For example, as shown in Fig. 8A, the plurality of vibration damping devices 90 that are located on the inner layer 42 of the outer shell 32 between the trailing edge 30 and the trailing edge shear web 52 may each have a width W of four resonating units 92. The plurality of vibration damping devices 90 located on the inner layer 42 between the trailing edge shear web 52 and the main shear web 52 may each have a width W of three resonating units 92. And the plurality of vibration damping devices 90 located on the inner layer 42 between the main shear web 52 and the leading edge 28 may each have a width W of two resonating units 92. In one embodiment, the base member 94 and the top member 96 of the vibration damping device 90 may be slightly curved to accommodate a curvature of the inner layer 42 of the wind turbine blade 20, for example. To this end, the void 98 defined by each resonating unit 92 may be generally trapezoidal in shape.

One or more vibration damping devices 90 may be attached to other interior surfaces of the wind turbine blade 20, as shown in Fig. 8C. In that regard, the base member 94 of each vibration damping device 90 may be adhesively bonded to the shear web 52 of the wind turbine blade 20. As shown, one or more one or more vibration damping devices 90 may be attached to the internal facing surface 76 of the web structure 58. In particular, the one or more vibration damping devices 90 may be arranged in parallel strips that are spaced apart in the spanwise S direction along the length of web structure 58 of the shear web 52. To that end, each vibration damping device 90 may be arranged such that the width W of the vibration damping device 90 extends across the height of the blade 20. Thus, the width W of each vibration damping devices 90 may be generally perpendicular to the chordwise C direction of the blade 20. Depending on the size constraints of the shear webs 52 of the wind turbine blade 20, the width W of each vibration damping device 90 may be varied. For example, as shown in Fig. 8C, the plurality of vibration damping devices 90 that are located on the trailing edge shear web 52 may each have a width W of four resonating units 92. The plurality of vibration damping devices 90 that are located on the main shear web 52 may each have a width W of three resonating units 92. To this end, the width W of the vibration damping devices 90 may be varied along the length of the wind turbine blade 20. For example, the width W of each vibration damping device 90 may be greater near the root end 24 of the blade 20 compared to the tip end 26.

Turning now with reference to Fig. 8D, a vibration damping module 110 is shown in accordance with an embodiment of the invention. The vibration damping module 110 includes a plurality of vibration damping devices 90 arranged on a substrate 112. The substrate 112 may be corrugated and configured to be attached to surfaces of the wind turbine blade 20, such as the inner layer 42 of the wind turbine blade 20 or the internal facing surface 76 of the web structure 58 to facilitate installation of a plurality of vibration damping devices 90. That is, instead of individually installing each vibration damping device 90 onto surfaces of the wind turbine blade 20, a single vibration damping module 110 can instead be installed. The substrate 112 may be adhesively bonded to surfaces of the wind turbine blade 20, and the installation of the vibration damping module 110 installs all the included vibration damping devices 90 to the wind turbine blade 20.

With continued reference to Fig. 8D, the plurality of vibration damping devices 90 may be adhesively bonded to the substrate 112. In that regard, the substrate 112 may be corrugated and defines a plurality of generally C-shaped channels 114 that extend along a length of the substrate 112 measured between a first end 116 of the substrate 112 to an opposite second end 118. The vibration damping devices 90 may be arranged on the substrate 112 such that the width W of each vibration damping device 90 may be generally perpendicular to the channels 114. In that regard, the vibration damping devices 90 may be spaced apart along the length of the substrate 112. The base member 94 of each vibration damping device 90 includes a plurality trapezoidal-shaped projections 120. The projections 120 on the base member 94 of each vibration damping device 90 extend along the length L of the vibration damping device 90. As shown, the projections 120 are configured to be received within each of the channels 114 to thereby facilitate attachment of the vibration damping device 90 to the substrate 112.

Fig. 8E illustrates the vibration damping module 110 according to another embodiment of the invention. As shown, the plurality of vibration damping devices 90 may be arranged on the substrate 112 such that the width W of each vibration damping device 90 is aligned with the channels 114. In that regard, the projections 120 on the base member 94 of each vibration damping device 90 extend along the width W of the vibration damping device 90. The vibration damping module 110 shown in Fig. 8E includes three vibration damping devices 90 that are spaced apart along a width of the substrate 112 measured between a pair of sides 113 of the substrate 112. To this end, the vibration damping module 110 may include fewer or more vibration damping devices 90, depending on the length L of each vibration damping device 90, which may be varied.

Turning now with reference to Figs. 9A-10D, a modular resonating segment 130 will now be described in accordance with embodiments of the invention. The modular resonating segment 130 may serve the same function as the resonating member 62 described above with respect to Figs. 1-8E, and is configured to dissipate vibrational energy away from surfaces of the wind turbine blade 20 to which it is attached. However, as will be described in further detail below, a plurality of modular resonating segments 130 are configured to be joined together to form a vibration damping device 132 having a plurality of resonating units 134. The vibration damping device 132 may be similar to the vibration damping device 90 described above with respect to Figs. 8A-8E except for being formed from a plurality of modular resonating segments 130. The construction of parts of each modular resonating segment 130 may be similar to the construction of the resonating member 62 described above with respect to Figs. 1-8E. Figs. 9A-9B illustrate the modular resonating segment 130 according to one embodiment of the invention. As shown, the modular resonating segment 130 includes a base member 136 from which a generally L-shaped resonating member 138 projects. In that regard, the modular resonating segment 130 may be generally C-shaped. The base member 136 includes a generally flat or panel-like body 140 that extends from a first end 142 to an opposite second end 144 of the modular resonating segment 130. As shown, the second end 144 of the modular resonating segment 130 defines an opening to the generally C-shaped profile of modular resonating segment 130. The body 140 of the base member 136 includes a thickness measured between an upper surface 146 and a lower surface 148 of the base member 136. As shown, the resonating member 138 may be positioned closer to the first end 142 compared to the second end 144 of the modular resonating segment 130. In particular, the resonating member 138 may be spaced a distance from the first end 142 of the modular resonating segment 130 to define a tab 150 that extends from the body 140 of the base member 136. The tab 150 may have a thickness that may be less than the thickness of the body 140 of the base member 136. As shown, the tab 150 forms a continuous extension of the lower surface 148 of the body 140 of the base member 136. The second end 144 of the body 140 of the base member 136 includes a shoulder that defines a tongue 152. The tongue 152 forms a continuous extension of the upper surface 146 of the body 140 of the base member 136. As will be described in further detail below, a plurality of modular resonating segments 130 are configured to be connected in an end-to-end arrangement to form the vibration damping device 132. In that regard, the tongue 152 of the base member 136 of a first modular resonating segment 130 is configured to be received over a tab 150 of the base member 136 of an adjacent, second modular resonating segment 130 to connect the two modular resonating segments 130 together.

With continued reference to Fig. 9A-9B, the modular resonating segment 130 includes the generally L-shaped resonating member 138 which projects upwardly from the base member 136. In particular, the resonating member 138 includes a first leg portion 154 that projects generally perpendicularly from the upper surface 146 of the base member 136 to a second leg portion 156. The second leg portion 156 may define the distal end of the modular resonating segment 130, for example. The second leg portion 156 may be arranged generally 90° relative to the first leg portion 154, and extends from the first leg portion 154 in a direction towards the second end 144 of the modular resonating segment 130. As shown in Fig. 9B, the second leg portion 156 may extend a distance beyond the tongue 152 of the base member 136. The first leg portion 154 may have a thickness measured between a first side surface 158 and a second side surface 160 that may be similar to the thickness of the body 140 of the base member 136, for example.

With continued reference to Figs. 9A-9B, the second leg portion 156 of the resonating member 138 extends from a first end 162 adjacent the first leg portion 154 to an opposite, second free end 164. As shown, the second leg portion 156 extends generally in parallel with the base member 136 of the modular resonating segment 130. The second leg portion 156 includes a thickness measured between an upper surface 166 and a lower surface 168 of the second leg portion 156. The second leg portion 156 includes a ledge 170 formed at the first end 162 and a tongue 172 formed at the second end 164. As shown, the ledge 170 may be formed in the upper surface 166 of the second leg portion 156 and the tongue 172 may be formed as a result of a shoulder formed in the lower surface 168 of the second leg portion 156. The ledge 170 and the tongue 172 may each have a thickness that may be less than the thickness of the second leg portion 156. As will be described in further detail below, a plurality of modular resonating segments 130 are configured to be connected in an end-to-end arrangement to form the vibration damping device 132. In that regard, the tongue 172 of a first modular resonating segment 130 is configured to be received over the ledge 170 of an adjacent, second modular resonating segment 130 to connect the two modular resonating segments 130 together.

Referring now to Figs. 9C and 9D, and as briefly described above, a plurality of modular resonating segments 130 are configured to be connected in an end-to-end arrangement to form the vibration damping device 132. As shown in Fig. 9C, a first modular resonating segment 130a, a second modular resonating segment 130b, and a third modular resonating segment 130c are connected together in an end-to-end arrangement, as indicated by directional arrows A1 , to form the exemplary vibration damping device 132. The vibration damping device 132 further includes an end segment 178 configured to enclose the open second end 144 of the last modular resonating segment 130 in the series, as will be described in further detail below. With respect to modular resonating segment 130a-130c, the inclusion of a suffix (such as "a," "b," etc.) serves to indicate the first, second, and third components respectively, rather than suggesting any structural distinction.

As shown, the first end 142b of the second modular resonating segment 130b may be received by the second end 144a of the first modular resonating segment 130a. In particular, the tongue 152a of the first modular resonating segment 130a may be received over the tab 150b of the second modular resonating segment 130b to form a base joint 174 and the tongue 172a of the first modular resonating segment 130a may be received over the ledge 170b of the second modular resonating segment 130b to form a top joint 176, as shown in Fig. 9D. Likewise, the first end 142c of the third modular resonating segment 130c may be received by the second end 144b of the second modular resonating segment 130b. In particular, the tongue 152b of the second modular resonating segment 130b may be received over the tab 150c of the third modular resonating segment 130c to form a base joint 174 and the tongue 172b of the second modular resonating segment 130b may be received over the ledge 170c of the second modular resonating segment 130c to form a top joint 176, as shown in Fig. 9D. The modular resonating segments 130 may be adhesively bonded together at each joint 174, 176. This process may be repeated for each modular resonating segment 130 connected in series. In that regard, each pair of connected modular resonating segments 130 forms one resonating unit 134. For example, the first leg portion 154b of an adjoining, second modular resonating segment 130b closes the open second end 144a of a first modular resonating segment 130a to define one resonating unit 134. Each resonating unit 134 defines an open-ended void or passageway 180 that extends through the vibration damping device 90.

Thus, the vibration damping device 90 may be considered an open-cell device, with the voids 180 being open to the surrounding environment, such as the interior 38 of the wind turbine blade 20. As briefly mentioned above, the vibration damping device 132 further includes an end segment 178 configured to enclose the open second end 144c of the last modular resonating segment 130c that forms the vibration damping device 132. As shown, the end segment 178 includes a resonating member 182 which may be similar in size to the first leg portion 154 of the resonating member 138 of the modular resonating segment 130. The resonating member 182 extends from a base end 184 to a distal end 186. The base end 184 includes a tab 188 that may be similar in size to the tab 150 of the base member 136 of the modular resonating segment 130. As indicated by directional arrow A2 in Fig. 9C, the end segment 178 is configured to be enclose the open second end 144c of the last modular resonating segment 130c that forms the vibration damping device 132. In particular, the distal end 186 of the end segment 178 may be received into engagement with the tongue 172c of the third modular resonating segment 130c to form a first end joint 190 and the tongue 152c of the third modular resonating segment 130c may be received over the tab 188 of the end segment 178 to form a second end joint 192, as shown in Fig. 9D. The end segment 178 may be adhesively bonded to the resonating segment 130c at each joint 190, 192.

With reference to Figs. 10A-10D, the base member 136 and the second leg portion 156 of the resonating member 138 of each modular resonating segment 130 that forms the vibration damping device 132 may be slightly curved or arcuate to accommodate a curvature of surfaces of the wind turbine blade 20, for example. The process for assembling the modular resonating members 130 together to form the vibration damping device 132 may be the same as the process described above with respect to Figs. 9C and 9D. However, the resultant void 180 defined by each resonating unit 134 may be generally trapezoidal in shape, as shown in Fig. 10D.

Turning now with reference to Figs. 11A and 11C, a plurality of vibration damping devices 132 are shown installed in the interior 38 of the wind turbine blade 20, similar to the embodiment of the vibration damping device 90 described above with respect to Figs. 8A-8C. In that regard, each resonating unit 134 may be generally box-shaped. The vibration damping device 132 further includes a width W between a first end 196 and a second end 198 and length L, as shown in Figs. 11A-11 B. The width W of each vibration damping device 132 may be in terms of resonating units 134, for example. In that regard, the vibration damping device 134 may be one, two, three, four, or more resonating units 134 in width W. As shown, each vibration damping device 134 may be elongate in the widthwise W direction. That is, the width W of the vibration damping device 134 may be greater than the length L of the vibration damping device 134.

One or more vibration damping devices 90 may be attached to interior surfaces of the wind turbine blade 20, as shown in Fig. 11 A. In that regard, the base member 136 of each modular resonating segment 130 that forms the vibration damping device 134 may be adhesively bonded to the inner layer 42 of the outer shell 32 of the blade 20. As shown, one or more one or more vibration damping devices 134 may be attached to the inner layer 42 at locations there along between the trailing edge 30 and the trailing edge shear web 52, between the trailing edge shear web 52 and the main shear web 52, and/or between the main shear web 52 and the leading edge 28, or any combination thereof. To this end, the vibration damping devices 134 may be arranged on the inner layer 42 of the first half-shell portion 34 or the second half-shell portion 36, or both. As shown in Fig. 11 A, the vibration damping devices 134 may be arranged in parallel strips that may be spaced apart in the spanwise S direction along the length of the wind turbine blade 20. To that end, each vibration damping device 134 may be arranged such that the width W of the vibration damping device 134 extends in the chordwise C direction of the wind turbine blade 20.

Depending on the size constraints of the interior 38 of the wind turbine blade 20, the width W of each vibration damping device 134 may be varied, such as by adding or removing modular resonating segments 130. For example, as shown in Fig. 11 A, the plurality of vibration damping devices 134 that are located on the inner layer 42 of the outer shell 32 between the trailing edge 30 and the trailing edge shear web 52 may each have a width W of four resonating units 134 formed from four modular reasoning segments 130 and one end segment 178. The plurality of vibration damping devices 134 located on the inner layer 42 between the trailing edge shear web 52 and the main shear web 52 may each have a width W of three resonating units 134. And the plurality of vibration damping devices 134 located on the inner layer 42 between the main shear web 52 and the leading edge 28 may each have a width W of two resonating units 134. As shown in Fig. 11 C, one or more vibration damping devices 134 may be attached to other interior surfaces of the wind turbine blade 20. In that regard, one or more vibration damping devices 134 may be adhesively bonded to the shear web 52 of the wind turbine blade 20. As shown, one or more vibration damping devices 134 may be attached to the internal facing surface 76 of the web structure 58. In particular, the one or more vibration damping devices 134 may be arranged in parallel strips that may be spaced apart in the spanwise S direction along the length of web structure 58 of the shear web 52. To that end, each vibration damping device 134 may be arranged such that the width W of the vibration damping device 134 extends across the height of the blade 20. Thus, the width W of each vibration damping devices 134 may be generally perpendicular to the chordwise C direction of the blade 20.

Turning now with reference to Figs. 12A-12I, a vibration damping device 122 is shown in accordance with another embodiment of the invention. In that regard, like reference numerals represent like features compared to the embodiments of the vibration damping devices 60, 90, 132 described above with respect to Figs. 1-11 C. The primary difference between the vibration damping device 122 of this embodiment and the vibration damping devices 60, 90, 132 of the previously described embodiment is that the vibration damping device 122 may be arranged as an annular or ring-shaped vibration damping device.

With reference to Figs. 12A and 12B, the vibration damping device 122 includes a plurality of resonating members 62 connected together to form a plurality of resonating units 92. In particular, the plurality of resonating members 62 may be spaced apart along a common base member 94 to which the attachment end 68 of each resonating member 62 is joined or integrated. The distal end 70 of each resonating member 62 may be joined or integrated with a common top member 96. In that regard, the resonating members 62, the top member 96, and base member 94 may be formed together as a unitary piece that is the vibration damping device 122. However, in an alternative embodiment, the vibration damping device 122 may be formed of a plurality of connected modular resonating segments 130. In either case, each of the plurality of resonating units 92 defines an open-ended void or passageway 98 that extends through the vibration damping device 122. As shown, the vibration damping device 122 includes a length L (e.g., Fig. 12B) that corresponds to the length L of each resonating member 62.

As shown, the vibration damping device 122 may be attached to interior surfaces of the wind turbine blade 20, and particularly to interior surfaces at the root end 24 of the wind turbine blade 20. In that regard, one or more vibration damping devices 122 are shown attached to the inner layer 42 of the outer shell 32 of the blade 20. The vibration damping devices 122 may be located within the interior 38 of the root end 24 of the blade 20. The base member 94, which may form a radially outer ring of the annular vibration damping device 122, may be adhesively bonded to the inner layer 42 of the outer shell 32. The top member 96 may for a radially inner ring of the annular damping device 122. In that regard, the vibration damping device 122 extends a height H, in a radially inward direction from the inner layer 42. The height H of the vibration damping device 122 may generally correspond to a height H of the plurality of resonating members 62. As shown in Fig. 12B, the plurality of vibration damping devices 122 may be arranged in coaxial rings or bands that are spaced apart in the spanwise S direction along the length of the wind turbine blade 20.

Fig. 12C illustrates the annular vibration damping device 122 according to another embodiment of the invention. As shown, the width W of the vibration damping device 122 may be larger compared to that shown in Fig. 12B. The width W of the vibration damping device 122 may be varied to dissipate different bands of vibrational energy frequencies, for example. As shown in Fig. 12D, the spacing of the vibration damping devices 122 in the spanwise S direction along the length of the wind turbine blade 20 122 may also be varied. In one embodiment, as shown in Fig. 12E, the vibration damping device 122 may have a width W that extends for a majority of the spanwise S length of the root end 24 of the wind turbine blade 20. In that regard, only one vibration damping device 122 may be attached to the root end 24 of the wind turbine blade 20.

Fig. 12F illustrates a vibration damping device 124 according to another embodiment of the invention. In that regard, like reference numerals represent like features compared to the embodiments of the vibration damping device 122 described above with respect to Figs. 12A-12E. However, compared to the previously described vibration damping device 122, the vibration damping device 124 of this embodiment may be semi-circular in shape, resembling a half-moon or crescent. In that regard, the vibration damping device 124 extends in a curved manner from the first end 100 to the second end 102 to define the semi-circular shape. To this end, the vibration damping device 124 may extend for any fraction of the full circumference of the root end 24 of the blade 20.

As shown in Fig. 12G, one or more vibration damping devices 122 may be attached to other surfaces of the wind turbine blade 20. In that regard, the vibration damping device 122 may be attached to exterior surfaces of the wind turbine blade 20, and particularly to exterior surfaces at the root end 24 of the wind turbine blade 20. As shown, one or more vibration damping devices 122 may be attached to the outer layer 44 of the outer shell 32 of the blade 20. The base member 94, which may form a radially inner ring of the annular vibration damping device 122, may be adhesively bonded to the outer layer 44 of the outer shell 32. The top member 96 may for a radially outer ring of the annular damping device 122. In that regard, the vibration damping device 122 extends a height H, in a radially outward direction from the outer layer 44. The plurality of vibration damping devices 122 may be arranged in coaxial rings or bands that may be spaced apart in the spanwise S direction along the length of the wind turbine blade 20.

Fig. 12H illustrates an annular vibration damping device 126 according to another embodiment of the invention. In that regard, like reference numerals represent like features compared to the embodiments of the vibration damping device 122 described above with respect to Figs. 12A-12E. However, compared to the previously described vibration damping device 122, a thickness T of the plurality of resonating members 62 may be varied. As shown, the thickness T of the plurality of resonating members 62 may be greater than that shown in Fig. 12A, for example. As a result, the resonating members 62 of the vibration damping device 126 shown in Fig. 12H may be stiffer to dissipate different bands of vibrational energy frequencies. By increasing the thickness T of the resonating members 62, the size of the void or passageway 98 of each resonating unit 92 may be changed, and may be smaller, for example. Fig. 121 illustrates an annular vibration damping device 128 according to another embodiment of the invention. In that regard, like reference numerals represent like features compared to the embodiments of the vibration damping device 122 described above with respect to Figs. 12A-12E. However, compared to the previously described vibration damping device 122, a thickness T of the base member 94 and a thickness T of the top member 96 may be varied. As shown, the thickness T of the base member 94 and the thickness T of the top member 96 may be greater than that shown in Fig. 12A, for example. In an alternative embodiment, only the thickness T of the base member 94 or the thickness T of the top member 96 may be varied. In either case, by increasing the thickness T of the thickness T of the base member 94 and the thickness T of the top member 96, the size of the void or passageway 98 of each resonating unit 92 may be changed, and may be smaller, for example.

Turning now with reference to Fig. 13A, a modular resonating segment 200 is shown in accordance with another embodiment of the invention. In that regard, like reference numerals represent like features compared to the embodiment of the modular resonating segment 130 described above with respect to Figs. 9A-11 C. The primary difference between the modular resonating segment 200 of this embodiment and the modular resonating segment 130 of the previously described embodiment is the configuration of the resonating member 202. To this end, a plurality of modular resonating segments 200 are configured to be joined together to form a vibration damping device 204 having a plurality of resonating members 202.

As shown in Fig. 13A, the modular resonating segment 200 includes a base member 136 from which the resonating member 202 projects. The resonating member 202 projects from the base member 136 to a free, distal end 206. In that regard, the resonating member 200 may be similar to the resonating member 62 described above with respect to Figs. 1-7B. The construction of the base member 136 of each modular resonating segment 200 may also be similar to the construction of the resonating member 62 described above with respect to Figs. 1-7B. The base member 136 includes a generally flat or panel-like body 140 that extends from a first end 208 to an opposite second end 210 of the modular resonating segment 200. The body 140 of the base member 136 includes a thickness measured between an upper surface 146 and a lower surface 148 of the base member 136. As shown, the resonating member 138 may be positioned closer to the first end 208 compared to the second end 210 of the modular resonating segment 200. In particular, the resonating member 202 may be spaced a distance from the first end 208 of the modular resonating segment 200 to define a tab 150 that extends from the body 140 of the base member 136. The tab 150 may have a thickness that may be less than the thickness of the body 140 of the base member 136. As shown, the tab 150 forms a continuous extension of the lower surface 148 of the body 140 of the base member 136. The second end 144 of the body 140 of the base member 136 includes a shoulder that defines a tongue 152.

With reference to Fig. 14A, a plurality of modular resonating segments 200 are configured to be connected in an end-to-end arrangement to form the vibration damping device 204 according to one embodiment of the invention. Alternatively, the vibration damping device may be formed as a unitary piece. While the vibration damping device 204 may be ring-shaped, it will be understood that the modular resonating segments 200 may be connected together to form a non-ring-shaped or non-circular vibration damping device. In any event, the tongue 152 of the base member 136 of a first modular resonating segment 130 is configured to be received over a tab 150 of the base member 136 of an adjacent, second modular resonating segment 130 to connect the two modular resonating segments 130 together. In that regard, the tongue 152 of a first modular resonating segment 200 may be received over the tab 150 of a second modular resonating segment 200 to form a base joint 174. The vibration damping device 204 may be formed by repeating this process to connect each modular resonating segment 200 in series. In the embodiment shown, the modular resonating segments 200 may be connected continuously so as to form an annular or ring-shaped vibration damping device 204. In that regard, the bodies 140 of the connected modular resonating segment 200 define a uniform base member 212 that may be adhesively bonded to surfaces of the wind turbine blade 20. In particular, the vibration damping device 204 may be positioned within the interior 38 of the root end 24 of the wind turbine blade 20. As shown, the vibration damping device 204 may be attached to an interior surface at the root end 24 of the blade 20, and specifically the inner layer 42 of the outer shell 32 of the blade 20. As a result, the plurality of resonating members 202 extend circumferentially about the root end 24 of the wind turbine blade 20 to form the vibration damping device 204, being an annular ring of resonating members 202. However, the vibration damping device 204 may be attached to various other locations on the wind turbine blade 20, including both interior and exterior surfaces of the wind turbine blade 20.

Turning now with reference to Figs. 13B and 14B, a modular resonating segment 220 is shown in accordance with another embodiment of the invention. In that regard, like reference numerals represent like features compared to the embodiment of the modular resonating segment 200 described above with respect to Figs. 13A and 14A. The primary difference between the modular resonating segment 220 of this embodiment and the modular resonating segment 200 of the previously described embodiment is that the modular resonating segment 220 includes a bulge 222 at the free, distal end 206. The bulge 222 may be cylindrical, having a circular cross-sectional shape. The bulge 222 may include a mass, a void, or be formed of a material different from the remainder of the resonating member 202. The process for assembling the modular resonating members 222 together to form a vibration damping device 224, as shown in Fig. 14B, may be the same as the process described above with respect to Figs. 13A and 14A. Alternatively, the vibration damping device 224 may be formed as a unitary piece. The vibration damping device 224 is shown attached to an interior surface at the root end 24 of the blade 20, and specifically the inner layer 42 of the outer shell 32 of the blade 20. However, the vibration damping device 224 may be attached to various locations, including both interior and exterior surfaces of the wind turbine blade 20.

Fig. 15A illustrates an annular vibration damping device 230 according to another embodiment of the invention. In that regard, like reference numerals represent like features compared to the embodiments of the vibration damping device 122 described above with respect to Figs. 12A-12E. As shown, the vibration damping device 230 includes a base member 94, which may form a radially outer ring of the annular vibration damping device 230 and a top member 96 which may for a radially inner ring of the annular vibration damping device 230. The vibration damping device 230 further includes a plurality of resonating members 232 that extend between the base member 94 and the top member 96. In particular, each resonating member 232 extends from the base member to a distal end 234. The distal end 234 of each resonating member 232 may be bridged together via the top member 96, being the distal-most part of the vibration damping device 230 relative to surfaces of the wind turbine blade 20. As shown, pairs of resonating members 232 intersect to form a plurality of X-shaped resonating units 236. Each resonating unit 236 defines an upper void or passageway 238 and a lower void or passageway 240. A plurality of central voids or passageways 242 may be formed between adjacent resonating units 236. As shown, the vibration damping device 230 may be attached to an interior surface at the root end 24 of the blade 20, and specifically the inner layer 42 of the outer shell 32 of the blade 20. However, the vibration damping device 230 may be attached to various locations, including both interior and exterior surfaces of the wind turbine blade 20. The construction of parts of the annular vibration damping device 230 may be similar to the construction of the resonating member 62 described above with respect to Figs. 1-7B.

Fig. 15B illustrates an annular vibration damping device 250 according to another embodiment of the invention. As shown, the vibration damping device 250 includes a ring-shaped body 252 which defines a radially outer surface 254 and a radially inner surface 256. Formed in the body 252 may be a plurality of tear-drop shaped voids or passageways 258 which extend in a width-wise direction through the body 252 of the vibration damping device 250. The voids 258 may be spaced apart about a circumference of the body 252 of the vibration damping device 250 to define a plurality of resonating members 260. Each resonating member 260 extends from the radially inner surface 256 to a distal end 262. The distal end 262 of each resonating member 260 may be bridged together at the radially inner surface 256. Each void 258 includes a rounded, bulbous end 264 at one side and a pointed or narrow end 266 on the opposite side. The bulbous end 264 may be positioned adjacent to the radially outer surface 254 of the body 252 and the narrow end 266 may be positioned adjacent to the radially inner surface 256. As shown, the vibration damping device 250 may be attached to an interior surface at the root end 24 of the blade 20, and specifically the inner layer 42 of the outer shell 32 of the blade 20. However, the vibration damping device 250 may be attached to various locations, including both interior and exterior surfaces of the wind turbine blade 20. While the present invention has been illustrated by a description of various preferred embodiments and while these embodiments have been described in some detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Thus, the various features of the invention may be used alone or in any combination depending on the needs and preferences of the user.

Claims

1 . A wind turbine blade (20) extending longitudinally in a spanwise direction between a root end (24) and a tip end (26), and extending in a chordwise direction between a leading edge (28) and a trailing edge (30), the wind turbine blade (20) comprising: a first opposing half-shell portion (34) and a second opposing half-shell portion (36) which together define an interior (38) of the wind turbine blade (20); at least one shear web (52) extending between the first opposing half-shell portion (34) and the second opposing half-shell portion (36); and at least one vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) for reducing noise emission from the wind turbine blade (20), the at least one vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) including at least one resonating member (62, 138, 202, 232, 260) that extends from a surface of the wind turbine blade (20) to a distal end (70, 96, 156, 186, 206, 234, 262) that is configured to oscillate to dissipate vibrational energy away from the surface of the wind turbine blade (20).

2. The wind turbine blade (20) of claim 1 , wherein the at least one vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) is located within the interior (38) of the wind turbine blade (20) such that the surface that the at least one resonating member (62, 138, 202, 232, 260) extends from is an interior surface of the wind turbine blade (20).

3. The wind turbine blade (20) of claim 2, wherein the interior surface is on the at least one shear web (52).

4. The wind turbine blade (20) of claim 2, wherein the interior surface is on the first opposing half-shell portion (34) or the second opposing half-shell (36).

5. The wind turbine blade (20) of any of the preceding claims, wherein the at least one resonating member (62) includes a core (78) and an outer skin (80).

6. The wind turbine blade (20) of claim 5, wherein the core (78) includes a resilient core material and a mass (84) positioned adjacent to the distal end (70) of the at least one resonating member (62).

7. The wind turbine blade (20) of any of claims 2-6, wherein the at least one vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) comprises at least a first vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) and a second vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) spaced apart and separately attached to the interior surface of the wind turbine blade (20).

8. The wind turbine blade of claim 7, wherein the first vibration damping device (60) and the second vibration damping device (60) extend in parallel.

9. The wind turbine blade (20) of any of claims 7 or 8, wherein the first vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) and the second vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) are configured to dissipate different bands of vibrational energy frequencies.

10. The wind turbine blade (20) of any of claims 2-9, wherein the at least one resonating member (62) is an elongate fin that extends a length along the surface of the wind turbine blade (20) in the spanwise direction.

11 . The wind turbine blade (20) of any of the preceding claims, wherein the at least one resonating member (62) includes a height measured between a first end attached to the interior surface of the wind turbine blade (20) and the distal end (70) and a thickness measured between a first side surface (72) and a second side surface (74), wherein the height is greater than the thickness.

12. The wind turbine blade (20) of claim 11 , wherein the first side surface (72) and the second side surface (74) of the at least one resonating member (62) are substantially planar.

13. The wind turbine blade (20) of any of the preceding claims, wherein the at least one resonating member (62) is wavy in transverse cross-section.

14. The wind turbine blade (20) of any of claims 11-13, wherein the height of the at least one resonating member (62) varies along a length of the at least one resonating member (62).

15. The wind turbine blade (20) of claim 1 , wherein the at least one vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) is located on an exterior of the wind turbine blade (20) such that the surface that the at least one resonating member (62, 138, 202, 232, 260) extends from is an exterior surface of the wind turbine blade (20).

16. The wind turbine blade (20) of claim 15, wherein the exterior surface is on the first opposing half-shell portion (34) or the second opposing half-shell portion (36).

17. The wind turbine blade (20) of any of the preceding claims, wherein the at least one damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) is located at the root end (24) of the wind turbine blade (20).

18. The wind turbine blade (20) of any of the preceding claims, wherein the at least one resonating member (62, 138, 202, 232, 260) comprises a plurality of resonating members (62, 138, 202, 232, 260) connected together at a base (94, 212, 254) of the at least one damping device (60, 90).

19. The wind turbine blade (20) of claim 18, wherein the at least one vibration damping device (90, 122, 124, 126, 128, 132, 204, 224, 230, 250) extends circumferentially about the root end (24) of the wind turbine blade (20) to form an annular ring of resonating members (62, 138, 202, 232, 260).

20. The wind turbine blade (20) of any of claims 18 or 19, wherein the plurality of resonating members (62, 138, 232) are bridged together at each distal end (70, 156,

21 . The wind turbine blade (20) of any of the preceding claims, wherein the at least one vibration damping device (90, 122, 124, 126, 128, 132, 204, 224, 230, 250) is located in the first one-third of the length of the wind turbine blade (20) measured from the root end (24).

22. A wind turbine (10) including the wind turbine blade (20) of any of the preceding claims.