Resonant structure of wind turbine blade

Abstract

A wind turbine blade (20) extending 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) comprises: a first opposing half-shell portion (34) and a second opposing half-shell portion (36) together defining 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). The wind turbine blade (20) further comprises at least one vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) for reducing noise emissions 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) extending from a surface of the wind turbine blade (20) to a distal end (70, 96, 156, 186, 206, 234, 262), the at least one resonating member being configured to oscillate to dissipate vibrational energy away from the surface of the wind turbine blade (20).

Description

TECHNICAL FIELD

[0001] The present application relates generally to wind turbines, and more particularly to systems and methods for damping vibrations of a wind turbine blade to reduce acoustic noise generated by the wind turbine blade during operation of the wind turbine. BACKGROUND

[0002] Wind turbines are used to generate electrical power using renewable resources without burning fossil fuels. Generally, a wind turbine converts kinetic energy from the wind into electrical energy. A horizontal axis wind turbine includes a tower, a nacelle at the top of the tower, and a rotor having a plurality of blades and supported in the nacelle by a shaft. The shaft directly or indirectly couples the rotor with a generator housed within the nacelle. Thus, when the wind forces the blades to rotate the rotor, the generator generates electrical energy. To this end, a wind turbine can be located on land (onshore) or within a body of water (offshore).

[0003] With the increase in demand for renewable energy in recent years, the number of wind turbines installed globally has also grown substantially. Furthermore, wind turbines have been developed to larger sizes to generate more power to meet the ever-growing demand for electrical energy. However, as wind turbines have become more prevalent, one of the challenges associated with wind turbines is the generation of acoustic noise during its operation, which can cause disturbances to nearby residents. The blades are one component of the wind turbine that can generate acoustic noise during operation.

[0004] Wind turbine blades, while designed to have aerodynamic efficiency, can experience various forms of vibrations during operation. These vibrations can be caused by factors such as turbulent flow, unsteady wind conditions, and mechanical interactions within the wind turbine structure. For example, during operation of the wind turbine, vibrations can be generated by mechanical equipment within the nacelle, such as the gearbox, the generator, and other equipment required for power generation. These vibrations can propagate from the nacelle and through the structure of the blade, thereby amplifying the total vibration energy that propagates along the length of the blade. As the vibration energy propagates along the length of the blade, it radiates into the surrounding air as acoustic waves, resulting in noise emissions.

[0005] Conventional methods to mitigate acoustic noise generated by wind turbine blades include reducing the overall aerodynamic noise of the turbine blade. These methods can include modifying the blade design, optimizing rotational speed, or applying a noise-reducing coating. Other methods include targeting the source of vibration energy that travels through the blade, for example, by using a vibration mount for the mechanical equipment within the nacelle. While these methods have proven some effectiveness, there remains a need to specifically address the problem of vibration energy traveling along the wind turbine blade and subsequently radiating as acoustic noise. SUMMARY

[0006] According to a first aspect of the present application, there is disclosed a wind turbine blade extending longitudinally in a spanwise direction between a root end and a tip end, and extending in a chordwise direction between a leading edge and a trailing edge. The wind turbine blade comprises: first and second opposing shell portions which together define an interior of the wind turbine blade; and at least one shear web extending between the first and second opposing shell portions. The wind turbine blade further comprises at least one vibration damping device for reducing noise emissions from the wind turbine blade. In this regard, the at least one vibration damping device comprises at least one resonant member extending from a surface of the wind turbine blade to a distal end, the at least one resonant member being configured to oscillate to dissipate vibrational energy away from the surface of the wind turbine blade. There is also disclosed a wind turbine comprising the wind turbine blade.

[0007] The at least one resonant member extends from a surface of the wind turbine blade to a distal end of the resonant member.

[0008] According to one embodiment of the present application, the at least one vibration damping device can be located within the interior of the wind turbine blade such that the surface from which the at least one vibration damping device extends from can be an interior surface of the wind turbine blade. For example, the interior surface can be located on the at least one shear web. Alternatively, the interior surface can be located on the first or second opposing shell portions.

[0009] According to another embodiment of the present application, the at least one resonant member can comprise a core and an outer skin. For example, the core can comprise a resilient core material and a mass located proximate to the distal end of the at least one resonant member.

[0010] In yet another embodiment of the present application, the at least one vibration damping device can comprise at least first and second vibration damping devices, the first and second vibration damping devices being spaced apart and separately attached to an interior surface of the wind turbine blade. In this regard, the first and second vibration damping devices can be configured to dissipate different frequency bands of vibrational energy frequencies. In yet another embodiment, the first and second vibration damping devices can extend in parallel.

[0011] In one embodiment of the present application, the at least one resonant member can be an elongate fin extending a length in a spanwise direction along an inner surface of the wind turbine blade. In another embodiment, the at least one resonant member can comprise a height measured between a first end and a distal end attached to the inner surface of the wind turbine blade and a thickness measured between a first side surface and a second side surface. The height of the at least one resonant member can be greater than the thickness. Furthermore, the first side surface and the second side surface of the at least one resonant member can be substantially planar between the first end and the distal end attached to the inner surface of the wind turbine blade. In one embodiment, the cross-section of the at least one resonant member can be wavy. In yet another embodiment, the height of the at least one resonant member can vary along the length of the at least one resonant member.

[0012] Preferably, the length of the resonant member is equal to or greater than the height of the resonant member. In this way, the elongate fin can dissipate vibrational energy more effectively. For example, the length can be at least 2 times, or at least 3 times, or at least 5 times, or at least 10 times the height. A more elongate fin can dissipate vibrational energy more effectively.

[0013] Preferably, the resonant member is attached to the inner surface of the wind turbine blade for the entire length, or substantially the entire length, of the wind turbine blade, e.g. greater than 50%, 60%, 70%, 80%, 90% or 95% of its length. In this way, the resonant member is able to effectively function as a vibration absorber and dissipate vibrational energy.

[0014] According to one embodiment of the present application, the at least one vibration damping device can be located on the exterior of the wind turbine blade such that the surface from which the at least one resonant member extends can be an outer surface of the wind turbine blade. For example, the outer surface can be located on the first or second opposing half shell portions.

[0015] In one embodiment, the at least one damping device can be located at the root end of the wind turbine blade. In yet another embodiment, the at least one resonant member can comprise a plurality of resonant members connected together at a base of the at least one damping device. In this regard, the plurality of resonant members can extend circumferentially around the root end of the wind turbine blade to form an annular ring of resonant members. Furthermore, the plurality of resonant members can be bridged together at each distal end to form a plurality of resonant units. According to one embodiment of the present application, the at least one vibration damping device can be located in the first third of the length of the wind turbine blade measured from the root end. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the application and, together with the general description of the application given in the following overview and the detailed description given below, serve to explain the application.

[0017] FIG. 1 is a perspective view of a wind turbine according to an embodiment of the application.

[0018] FIG. 2 is FIG. 1 a perspective view of a wind turbine blade of the wind turbine of

[0019] FIG. 3 is a cross-sectional view of the wind turbine blade shown in FIG. 2 taken generally along line 3-3.

[0020] FIG. 4 is a cross-sectional view of the wind turbine blade shown in FIG. 2 taken generally along line 4-4.

[0021] FIG. 5A is FIGS. 1-4 a cross-sectional view of a portion of the wind turbine blade of showing a vibration damping device attached to a shear web according to an embodiment of the application.

[0022] FIG. 5B is FIGS. 1-4 a cross-sectional view of a portion of the wind turbine blade of showing a vibration damping device attached to a shear web according to an embodiment of the application.

[0023] FIG. 5C is FIGS. 1-4 a cross-sectional view of a portion of the wind turbine blade of showing a plurality of vibration damping devices attached to a shear web according to an embodiment of the application.

[0024] FIG. 6A is FIGS. 1-4 a perspective view of a portion of a shear web of the wind turbine blade of showing a vibration damping device having a flat profile according to an embodiment of the application.

[0025] FIG. 6B is FIGS. 1-4 a perspective view of a portion of a shear web of the wind turbine blade of showing a vibration damping device having a tapered profile according to an embodiment of the application.

[0026] FIG. 6C is FIGS. 1-4 a perspective view of a portion of a shear web of the wind turbine blade of showing at least two vibration damping devices arranged in series and each having a tapered profile according to an embodiment of the application.

[0027] FIG. 6D is a perspective view of a portion of a shear web of a wind turbine blade shown in FIGS. 1-4

[0028] FIG. 6E is a perspective view of a portion of a shear web of a wind turbine blade shown in FIGS. 1-4

[0029] FIG. 6F is a perspective view of a portion of a shear web of a wind turbine blade shown in FIGS. 1-4

[0030] FIG. 7A is a cross-sectional view of a portion of a wind turbine blade shown in FIGS. 1-4

[0031] FIG. 7B is a cross-sectional view of a wind turbine blade shown in FIGS. 1-4

[0032] FIG. 8A is a perspective view of a cross-section of a wind turbine blade shown in FIG. 2

[0033] FIG. 8B is a perspective view of an exemplary vibration damping device according to an embodiment of the present invention.

[0034] FIG. 8C is a perspective view of a cross-section of a wind turbine blade shown in FIG. 2

[0035] FIG. 8D is a perspective view of a vibration damping module comprising a plurality of vibration damping devices according to an embodiment of the present invention.

[0036] FIG. 8E is a perspective view of a vibration damping module comprising a plurality of vibration damping devices according to another embodiment of the present invention.

[0037] FIG. 9A ​​​​​​​is a perspective view of a modular resonant section according to an embodiment of the application.

[0038] FIG. 9B is FIG. 9A a side view of the modular resonant section of

[0039] FIG. 9C shows a process for assembling a plurality of modular resonant sections together to form a vibration damping device according to an embodiment of the application.

[0040] FIG. 9D is FIG. 9C a side view of the vibration damping device being assembled in

[0041] FIG. 10A is a perspective view of a modular resonant section according to an embodiment of the application.

[0042] FIG. 10B is FIG. 10A a side view of the modular resonant section of

[0043] FIG. 10C shows a process for assembling a plurality of modular resonant sections together to form a vibration damping device according to an embodiment of the application.

[0044] FIG. 10D is FIG. 10C a side view of the vibration damping device being assembled in

[0045] FIG. 11A is FIG. 2 a perspective view of a cross-section of a wind turbine blade shown in FIG. 9D and FIG. 10D a plurality of vibration damping devices according to an embodiment of the application attached to the surface of a shear web of a wind turbine blade.

[0046] FIG. 11B is a perspective view of an exemplary vibration damping device according to an embodiment of the application.

[0047] FIG. 11C is FIG. 2 a perspective view of a cross-section of a wind turbine blade shown in FIG. 9D a plurality of vibration damping devices according to an embodiment of the application attached to the surface of a shear web of a wind turbine blade.

[0048] FIG. 12A is FIG. 2 a partial cross-sectional view of a root end of a wind turbine blade shown in

[0049] FIG. 12B isFIG. 2 is a perspective view of the root end of a wind turbine blade showing a plurality of ring-shaped vibration damping devices attached to the inner surface of the root end of the wind turbine blade.

[0050] FIG. 12C is FIG. 2 is a perspective view of the root end of a wind turbine blade showing a plurality of ring-shaped vibration damping devices attached to the inner surface of the root end of the wind turbine blade according to another embodiment of the present invention.

[0051] FIG. 12D is FIG. 2 is a perspective view of the root end of a wind turbine blade showing a plurality of ring-shaped vibration damping devices attached to the inner surface of the root end of the wind turbine blade according to another embodiment of the present invention.

[0052] FIG. 12E is FIG. 2 is a perspective view of the root end of a wind turbine blade showing a single ring-shaped vibration damping device attached to the inner surface of the root end of the wind turbine blade according to another embodiment of the present invention.

[0053] FIG. 12F is FIG. 2 is a perspective view of the root end of a wind turbine blade showing a plurality of semi-circular vibration damping devices attached to the inner surface of the root end of the wind turbine blade according to another embodiment of the present invention.

[0054] FIG. 12G is FIG. 2 is a perspective view of the root end of a wind turbine blade showing a plurality of ring-shaped vibration damping devices attached to the outer surface of the root end of the wind turbine blade.

[0055] FIG. 12H is FIG. 2 is a partial cross-sectional view of the root end of a wind turbine blade showing a ring-shaped vibration damping device attached to the inner surface of the wind turbine blade according to an embodiment of the present invention.

[0056] FIG. 12I is FIG. 2 is a partial cross-sectional view of the root end of a wind turbine blade showing a ring-shaped vibration damping device attached to the inner surface of the wind turbine blade according to an embodiment of the present invention.

[0057] FIG. 13A is a side view of a modular resonant section according to an embodiment of the present invention.

[0058] FIG. 13B is a side view of a modular resonant section according to another embodiment of the present invention.

[0059] FIG. 14A is FIG. 2 a partial cross-sectional view of a root end of a wind turbine blade showing an annular vibration damping device attached to an inner surface of the wind turbine blade formed of a plurality of modular resonant segments according to an embodiment of the present invention. FIG. 13A

[0060] FIG. 14B is FIG. 2 a partial cross-sectional view of a root end of a wind turbine blade showing an annular vibration damping device attached to an inner surface of the wind turbine blade formed of a plurality of modular resonant segments according to an embodiment of the present invention. FIG. 13B

[0061] FIG. 15A is FIG. 2 a partial cross-sectional view of a root end of a wind turbine blade showing an annular vibration damping device attached to an inner surface of the wind turbine blade according to an embodiment of the present invention.

[0062] FIG. 15B is FIG. 2 a partial cross-sectional view of a root end of a wind turbine blade showing an annular vibration damping device attached to an inner surface of the wind turbine blade according to an embodiment of the present invention. DETAILED DESCRIPTION

[0063] Referring to FIGS. 1-15B , embodiments of a vibration damping device for reducing noise emissions from a wind turbine and in particular from a wind turbine blade are shown. In this regard, during operation of the wind turbine, vibrations can be generated by mechanical equipment within the nacelle of the wind turbine, such as a gearbox, a generator and other equipment required for power generation. Energy from these vibrations is ultimately transferred to the nacelle structure. From the nacelle structure, these vibrations can propagate into the structure of the attached wind turbine blade, travelling along their length from the root end to the tip end. In particular, vibrations from different mechanical equipment can accumulate group velocity of vibration energy and thereby cause a resonant behaviour at specific frequencies as they travel along the length of the blade. The group velocity of the vibrations depends on various factors, including material properties of the blades, their structural features and the frequency of the vibrations. To this end, vibration energy is radiated from the blade in the form of sound waves as sound. In some cases, the vibrations can reach resonance, meaning that they match the natural frequency of the blade structure, resulting in increased amplitude and thus noise emission from the blade.

[0064] ​​To reduce the vibrational energy that is radiated from the blade as sound in the form of acoustic waves, one or more vibration damping devices in accordance with embodiments of the present application can 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 disrupt the group velocity of the propagating vibrations by absorbing and dissipating a significant portion of the vibrational energy from the surface of the wind turbine blade. By disrupting the group velocity and reducing the vibrational energy, the vibration damping devices attenuate the transmission of vibrations along the blade. As a result, the amount of vibrational energy that is radiated from the blade as sound in the form of acoustic waves (i.e., noise) is significantly reduced. These and other benefits of the present application will be described more fully below.

[0065] Reference FIG. 1 FIG. 1 shows an exemplary wind turbine 10 that 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 the gearbox, the nacelle 14 can house various components necessary to convert wind energy to electrical energy and to operate and optimize the performance of the wind turbine 10. The tower 12 supports the loads presented by the nacelle 14, the rotor 16, and other wind turbine components housed inside or outside the nacelle 14, and serves to elevate the nacelle 14 and the rotor 16 to an elevation above ground or sea level, as the case can be, at which air flows of lower turbulence and higher velocity are typically found.

[0066] 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 around the circumference of the central hub 18. In representative embodiments, the rotor 16 includes three blades 20, although the number of blades 20 can vary. The blades 20, which project radially outward from the central hub 18, are configured to interact with passing air flows to generate a rotational force that causes the central hub 18 to rotate about its longitudinal axis 22. The design, construction, and operation of the blades 20 are familiar to those of ordinary skill in the art of wind turbine design and can include additional functional aspects to optimize performance.

[0067] The rotor 16 can be coupled, directly or indirectly, to a gearbox (not shown) by a drive shaft (not shown) to form a rotor assembly. Either way, the gearbox transmits the rotation of the rotor 16 to the generator through a coupling (not shown). Wind in excess of a minimum speed can activate the rotor 16 such that the rotor 16 rotates in a direction substantially perpendicular to the wind and applies a torque to an input shaft of the generator. As understood by one of ordinary skill in the art, the electrical power generated by the generator can be supplied to a power grid (not shown) or an energy storage system (not shown) for later release to the power grid. In this way, the kinetic energy of the wind can be harnessed by the wind turbine 10 for power generation.

[0068] FIG. 2 is a schematic perspective view of an exemplary wind turbine blade 20. The blade 20 extends longitudinally in a spanwise S direction between a root end 24 and a tip end 26, and laterally in a chordwise C direction between a leading edge 28 and a trailing edge 30. The blade 20 includes an outer shell 32, which can be divided into a first (e.g., windward) half-shell portion 34 and a second (leeward) half-shell portion 36. For example, the outer shell 32 can be molded from glass fiber reinforced plastic (GRP). The first and second half-shell portions 34, 36 can be formed as separate pieces that are joined together along the leading and trailing edges 28, 30 to form the outer shell 32 of the blade 20. Alternatively, the outer shell 32 of the blade 20 can be formed as a single piece without any glued joints. In either case, the first and second half-shell portions 34, 36 of the outer shell 32 define a generally hollow interior 38 of the wind turbine blade 20. As FIGS. 3-4 As best shown in FIG. 1, portions of the outer shell 32 are a sandwich panel structure, which can include a blade core 40 of lightweight foam (e.g., polyurethane) sandwiched between inner and outer GRP layers or skins 42, 44. To this end, the inner layer 42 can form an inner surface of the wind turbine blade 20, and the outer layer 44 can form an outer surface of the wind turbine blade 20.

[0069] Reference is now made to FIGS. 2-4To increase strength and stiffness, the blade 20 also includes at least one spar structure 46 extending longitudinally between the root end 24 and the tip end 26 along at least a portion of the length of the blade 20 in the spanwise S direction. In the illustrated embodiment, the blade 20 includes two spar structures 46. However, it should be appreciated that the blade 20 can have fewer or more spar structures 46. Each spar structure 46 includes a pair of spar caps 48, 50 associated with the respective first and second half shell portions 34, 36 and a shear web 52 extending between the corresponding pair of opposing spar caps 48, 50. In the illustrated embodiment, the blade 20 includes two spar structures 46 and thus two shear webs 52, which can be referred to as a primary shear web and an aft shear web. To this end, each shear web 52 and associated pair of spar caps 48, 50 can extend generally from the root end 24 (e.g., FIG. 3 ) of the blade 20 through a mid-section (e.g., FIG. 4 ) of the blade 20 and generally to the tip end 26 of the blade 20.

[0070] The spar caps 48, 50 are generally designed to carry bending loads on the blade 20 and each shear web 52 is generally designed to carry shear loads on the blade 20. In one embodiment, the spar caps 48, 50 can 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 shown, for example, in FIG. 3 and FIG. 4 However, in alternative embodiments (not shown), the spar caps 48, 50 can be separate elements bonded to the inner surface 42 of the outer shell 32. In one embodiment, the spar caps 48, 50 can be formed from a stack of pultruded fibre-reinforced composite strips. However, in alternative embodiments, the spar caps 48, 50 can have a laminated composite structure composed of a plurality of fibre layers, resin and possibly a core material.

[0071] Each shear web 52 extends longitudinally in the spanwise S direction within the interior 38 of the wind turbine blade 20 and spans the height of the blade 20 from the first half shell portion 34 to the second half shell portion 36 and between the respective spar caps 48, 50. In the exemplary embodiment, each shear web 52 includes a lower flange 54, an upper flange 56, and a mid-web structure 58 extending between the lower flange 54 and the upper flange 56. The lower flange 54 and the upper flange 56 of each shear web 52 are configured to be bonded to the inner layer 42 of the shell 32 of the blade 20. In another embodiment, the lower flange 54 and the upper flange 56 of each shear web 52 can be bonded to the surface of the spar cap 48, 50, respectively. Each shear web 52 can be generally shaped as an I-beam. However, it will be appreciated by those of ordinary skill in the art that the shear web 52 can have different configurations and the figures are not intended to be limiting in this regard.

[0072] Referring now to FIG. 5A and FIG. 6A , a vibration damping device 60 for damping vibrations to reduce noise emissions from a wind turbine blade 20 according to a first embodiment of the present application is shown. As shown, the vibration damping device 60 can be positioned within the interior 38 of the blade 20 and attached to the interior surface of the blade 20 and, in particular, to one of the shear webs 52, such as the trailing edge shear web 52. However, while the vibration damping device 60 is shown and described with respect to one particular shear web 52, it will be appreciated that the vibration damping device 60 can be attached to any of the shear webs 52 of the blade 20, for example. As shown, the vibration damping device 60 can be attached to the web structure 58 of the shear web 52 generally at the midpoint between the lower flange 54 and the upper flange 56. As shown, the vibration damping device 60 can extend longitudinally along the shear web 52 in the spanwise S direction for a length. To this end, the vibration damping device 60 can span the entire length of the shear web 52 or only a portion of the length of the shear web 52. FIG. 6A

[0073] Continuing to refer to FIG. 5A and FIG. 6A , the vibration damping device 60 can be defined by at least one elongate resonant member 62. As shown, FIG. 6A the resonant member 62 can include a flat rectangular profile and extend in the spanwise S direction between a first end 64 and a second end 66 to define a length L of the resonant member 62. As shown, FIG. 5A ​As shown, the resonant member 62 extends in the chordal C direction between an attachment end 68 and a distal end 70 to define a height H of the resonant member 62. The resonant member 62 also includes a thickness T measured between a first side surface 72 and an opposing second side surface 74 of the resonant member 62. In this regard, the resonant member 62 exhibits a thin and flat profile similar to a fin. This is due to the fact that the thickness T of the resonant member 62 is significantly smaller compared to its height H. The resulting shape is a thin, flexible fin or strip-shaped resonant member 62 that is configured to oscillate to dissipate vibrational energy. In the illustrated embodiment, the first side surface 72 and the opposing second side surface 74 can be substantially planar. Similarly, the attachment end 68 and the distal end 70 of the resonant member 62 can also be substantially planar. Thus, the lateral (i.e., chordal C) cross-sectional shape of the resonant member 62 can be generally rectangular, as shown. However, the resonant member 62 can include other chordal C cross-sectional shapes, as will be described in further detail below. FIG. 5A

[0074] As best shown in FIG. 5A The resonant member 62 extends generally perpendicularly from an inward-facing surface 76 of the web structure 58 to which the resonant member 62 is attached. For example, the attachment end 68 of the resonant member 62 can be bonded to the surface 76 of the web structure 58. The attachment end 68 of the resonant member 62 is configured to be attached to the web structure 58 such that the resonant 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 resonant member 62 can be affixed to the web structure 58 while the distal end 70 of the resonant member 62 remains free and unsupported. The resonant member 62 protrudes outwardly from the surface 76 of the web structure 58 similar to a cantilevered beam arrangement. Depending on which side of the shear web 52 the vibrational damping device 60 is positioned, the resonant member 62 can extend in the chordal C direction from the web structure 58 toward either the leading edge 28 or the trailing edge 30 of the blade 20.

[0075] With continued reference to FIG. 5A ​The resonant member 62 can include a core 78 formed of a resilient core material and an outer skin 80. The core 78 can be formed of a fiber-reinforced composite material or a homogenous material such as a thermoplastic, foam, metal, or combinations thereof, depending on the desired vibrational behavior in situ. For example, at least one resonant member 62 can be formed of one or more pre-consolidated pultruded fiber composite strips. The outer skin 80 can be a layer of GRP, for example. As shown, the outer skin 80 can extend around the first side surface 72, the second side surface 74, and the distal end 70 of the resonant member 62. The core 78 material at the attachment end 68 of the resonant member 62 can remain uncovered and exposed to facilitate direct attachment of the resonant member 62 to the surface of the wind turbine blade 20. However, the outer skin 80 can completely cover the core material 78, leaving no portion of the core 78 material exposed. In another embodiment, the resonant member 62 can not include an outer skin 80.

[0076] The core material 78 can be resilient to provide the resonant member 62 of the vibration damping device 60 with the ability to oscillate within a predetermined target frequency range to dissipate vibrational energy traveling 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 resonant member 62 and dissipated as the vibrational energy travels toward the distal end 70. The resonant member 62 effectively acts as a vibration absorber or energy sink configured to absorb vibrational energy into its structure. By attaching the resonant member 62 to, for example, the shear web 52, which is a structural component of the wind turbine blade 20, the resonant member 62 is allowed to interact with vibrations propagating along the length of the blade 20. The interaction of the resonant member 62 effectively disrupts the transmission of vibrational energy from the root end 26 toward the tip end 28 of the blade 20, thereby mitigating the acoustic effect. In other words, the resonant member 62 dynamically absorbs and dissipates a substantial amount of vibrational energy through its oscillatory motion, thereby minimizing noise emissions from the wind turbine blade 20. To this end, as the resonant member 62 absorbs vibrational energy from the blade structure 20, the distal end 70 of the resonant member 62 moves relative to the attachment end 68 to effectively dissipate the vibrational energy absorbed by the resonant member 62 in the form of heat.

[0077] Strategically placing one or more vibration damping devices 60 at resonance points along the structure of the wind turbine blade 20, such as the shear web 52, further enhances the performance of the resonant member 62. In this regard, a resonance point is a location on the structure of the blade 20 where vibrations traveling along the blade 20 exhibit maximum amplitude. By positioning the vibration damping devices 60 at these key points, the resonant member 62 can target the region of highest vibration energy. Regarding the shear web 52, the resonance point can typically be located between flanges 54 and 56, for example, at the middle third of the web structure 58 between flanges 54 and 56. However, the precise location of the resonance point can vary depending on the specific design and construction of the wind turbine blade 20 and the shear web 52. Numerical simulations, experimental modal analyses, or structural dynamic analyses can be performed to identify and characterize these resonance points to locate the vibration damping devices 60. Furthermore, the height H, thickness T, and length L of the resonant member 62, as well as the core material 78 of the resonant member 62, can be varied to alter the vibration or oscillation behavior of the resonant member 62, targeting a specific frequency range of vibrations for which damping is desired. The frequency range of vibrations traveling along the wind turbine blade 20 can, for example, be between 50 Hz and 500 Hz. Moreover, since energy from mechanical vibrations is typically transferred from the nacelle 14 structure to the structure of the wind turbine blade 20 attached at the root end 24, positioning 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 third of the length of the wind turbine blade 20 measured from the root end 24, can be particularly effective.

[0078] FIG. 5B A vibration damping device 60 according to another embodiment of the present invention is shown. Similar to the above regarding... FIG. 5A and FIG. 6AIn the described embodiment, the resonant member 62 extends generally perpendicularly from a surface 76 of the web structure 58 to which the resonant member 62 is attached. In particular, the attachment end 68 of the resonant member 62 can be directly and adhesively attached to the surface 76 of the web structure 58. However, to reinforce the attachment of the resonant member 62 to the surface of the blade 20, such as the surface 76 of the web structure 58, a pair of L-shaped joint member 82 can be used. As shown, each joint member 82 is mounted on the contact edge between the attachment end 68 of the resonant member 62 and the surface 76 to which the resonant member 62 is attached. In the illustrated embodiment, one joint member 82 covers the contact edge between the first side surface 72 of the resonant 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 resonant member 62 and the surface 76 of the web structure 58. To this end, the joint members 82 can be adhesively attached to the surface 76 of the web structure 82 as well as the first and second side surfaces 72, 74 of the resonant member 62. The joint members 82 can be formed of a composite material, such as fiberglass or carbon fiber fabric. As noted above, these materials can be impregnated with resin and applied over the contact edges, thereby providing structural reinforcement and a protective outer layer for the resonant member 62.

[0079] With continued reference to FIG. 5B , the resonant member 62 can also include a mass 84 positioned adjacent the distal end 70. The mass 84 can be a concentration of the core material 78 or formed of a material different than the core material 78. In this regard, the mass 84 includes a density that can be different than the core material 78. As shown, the mass 84 can be covered by the outer skin 80. However, the mass 84 can be exposed or uncovered by the outer skin 80. The mass 84 can be elongate or rod-like and extend continuously over the entire length of the resonant member 62. However, the mass 84 can be segmented or extend only a portion of the length of the resonant member 62. The mass 84 enhances the ability of the resonant member 62 to dampen vibrations by altering the dynamic response characteristics of the resonant member 62. In particular, the addition of the mass 84 at the distal end 70 of the resonant member 62 affects the overall mass distribution and moment of inertia of the resonant member 62, resulting in a change in its natural frequency and damping characteristics. By increasing the mass at the free distal end 70 of the resonant member 62, the natural frequency of the resonant member 62 can be shifted, potentially allowing for a better alignment with the target frequency range of the vibrations of the blade 20 that are desired to be damped. This alignment enables the resonant member 62 to more strongly resonate with incoming vibrations, thereby increasing its effectiveness in absorbing and dissipating vibrational energy.

[0080] As noted above, one or more vibration damping devices 60 can be attached to the interior surface of a wind turbine blade 20. FIG. 5CExemplary embodiments are shown in which multiple vibration damping devices 60 can be attached to the shear web 52 separately at different locations along the web structure 58. For example, the vibration damping devices 60 can be installed with or without the joint members 82. As shown, three vibration damping devices 60 can be attached to the web structure 58. However, fewer or more vibration damping devices 60 can be attached to the web structure 58 and generally at different locations along the web structure 58 or shear web 52. In either case, the resonant members 62 of each of the multiple vibration damping devices 60 can extend parallel to one another and can extend parallel to components of the spar structure 46, such as the spar caps 48, 50. The resonant members 62 of each damping device 60 can be configured to dissipate vibration energy frequencies of the same frequency band or vibration energy frequencies of different frequency bands. In this regard, the resonant members 62 can have similar dimensions and configurations or be different. FIG. 5C In the exemplary embodiments shown, each resonant member 62 has a different height H and one resonant member 62 includes a mass 84 while the other two resonant 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 resonant members 62, and the inclusion of the core material 78 and / or mass 84 of the resonant members 62 can vary to modify the vibration or oscillation behavior of the vibration damping devices 60 to target certain frequency ranges of vibrations intended to be damped.

[0081] Reference is now made to FIGS. 6A-6F Different embodiments of the resonant members 62 of the vibration damping devices 60 will now be described. As noted above with respect to the FIG. 6A resonant member 62 can have a generally flat rectangular profile. That is, the first side surface 72 and the opposing second side surface 74 can be substantially planar and the attachment end 68 and the distal end 70 of the resonant member 62 can also be substantially planar. However, other configurations of the resonant member 62 are possible. For example, the distal end 70 of the resonant member 62 can be tapered. As FIG. 6B shown, the distal end 70 can taper gradually along the length L of the resonant member 62 from the first end 64 to the second end 66, resulting in the height H of the resonant member 62 being greater at the second end 66 than at the first end 64.

[0082] As FIG. 6C shown, multiple vibration damping devices 60 can be arranged in series to extend along the length of the wind turbine blade 20 and, in particular, along the length of the shear web 52. That is, rather than extending continuously along the length of the wind turbine blade 20 and shear web 52, the shear web 52 can include multiple vibration damping devices 60 arranged end-to-end along the length of the wind turbine blade 20 and shear web 52. As FIG. 6CAs shown, the resonant member 62 of each vibration damping device 60 can be tapered to define a consistent taper along the length of the wind turbine blade 20. However, each resonant member 62 of the series of vibration damping devices 60 can have the same or different configurations.

[0083] FIG. 6D A vibration damping device 60 according to an embodiment is shown, in which the height H of the resonant member 62 varies along the length L of the resonant member 62. That is, the distal end 70 of the resonant member 62 can be contoured, jagged, or otherwise not planar relative to the attachment end 68 of the resonant member 62. Similarly, FIG. 6E A vibration damping device 60 according to another embodiment is shown, in which the resonant member 62 is wavy in transverse (i.e., spanwise S) cross-sectional shape. That is, the position of the attachment end 68 along the height of the web structure 58 of the shear web 52 varies along the length L of the resonant member 62. FIG. 6F A vibration damping device 60 according to another embodiment is shown, in which the height H of the resonant member 62 varies along the length L of the resonant member 62 and the resonant member 62 is wavy in transverse (i.e., spanwise S) cross-sectional shape. Additionally or alternatively, the resonant member 62 can be wavy (e.g., S-shaped) in chordwise C cross-sectional shape.

[0084] One or more vibration damping devices 60 can be attached to the inner surface and / or the outer surface of the wind turbine blade 20. The inner surface or the outer surface can be on the first opposing half shell portion 34 or the second opposing half shell portion 36. FIG. 7A A vibration damping device 60 is shown positioned within the interior 38 of the blade 20 and attached to the inner surface of the blade 20 and specifically to the inner layer 42 of the shell 32 of the wind turbine blade 20. Specifically, the resonant member 62 of each vibration damping device 60 can be attached to the inner layer 42 of the first half shell portion 34. However, one or more vibration damping devices 60 can be attached to the first half shell portion 34 or the second half shell portion 36 or both. As FIG. 7B As shown, one or more vibration damping devices 60 can be attached to the inner layer 42 of each of the first half shell portion 34 and the second half shell portion 36 of the shell 32 of the blade 20. For example, one or more vibration damping devices 60 can be attached to the inner layer 42 at a location along the inner layer 42 between the trailing edge 30 and the trailing edge shear web 52, the trailing edge shear web 52 and the main shear web 52, and / or the main shear web 52 and the leading edge 28 or any combination thereof.

[0085] Referring now to FIGS. 8A-8E A vibration damping device 90 according to another embodiment of the present application is shown. In this regard, the vibration damping device 90 is similar to the vibration damping device 60 described above with respect to FIGS. 1-7BCompared with the described embodiment of the vibration damping device 60, the same reference numerals denote the same features. The main difference between the vibration damping device 90 of this embodiment and the vibration damping device 60 of the aforementioned embodiment is that the vibration damping device 90 includes a plurality of resonant members 62 connected together to form a plurality of resonant units 92. Specifically, the plurality of resonant members 62 may be spaced apart along a common base member 94, and the attachment end 68 of each resonant member 62 is connected to or integrated into the common base member 94. The distal end 70 of each resonant member 62 may be engaged or integrated with a common top member 96. In this respect, the resonant members 62, the top member 96, and the base member 94 may be formed together as an integral part of the vibration damping device 90. The construction of each member 62, 94, 96 may be similar to that described above. FIGS. 1-7B The resonant member 62 is described in its construction. For example, the vibration damping device 90 can be formed from fiber-reinforced composite materials or homogeneous materials, and can be formed via extrusion or pultrusion manufacturing methods.

[0086] like FIG. 8A and FIG. 8B As shown, each of the plurality of resonant units 92 defines an open gap or channel 98 at one end, the gap or channel 98 extending through the vibration damping device 90. Thus, the vibration damping device 90 can be considered an open device, wherein the gap 98 is open to the surrounding environment (such as the interior 38 of a wind turbine blade 20). Specifically, each resonant unit 92 may be generally box-shaped and includes two resonant members 62, which are bridged or connected together at their distal ends 70 by a top member 96 and at their attachment ends 68 by a 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 corresponding to the length L of each resonant member 62. The width W of each vibration damping device 90 can be expressed, for example, by the width of the resonant unit 92. In this respect, the width W of the vibration damping device 90 can be one, two, three, four, or more resonant units 92. The vibration damping device 90 may be elongated in the width W direction. That is, the width W of the vibration damping device 90 can be greater than the length L of the vibration damping device 90.

[0087] like FIG. 8AAs shown, one or more vibration damping devices 90 can be attached to the inner surface of the wind turbine blade 20. In this respect, the base member 94 of each vibration damping device 90 can be bonded to the inner layer 42 of the outer shell 32 of the blade 20. As shown, one or more vibration damping devices 90 can be attached to the inner layer 42 at locations along the inner layer 42 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. For this purpose, the vibration damping device 90 can be arranged on the inner layer 42 of the first half-shell portion 34 or the second half-shell portion 36, or both. FIG. 8A As shown, the vibration damping devices 90 can be arranged as parallel strips spaced apart in the spanwise S direction along the length of the wind turbine blade 20. For this purpose, each vibration damping device 90 can 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.

[0088] Depending on the dimensional constraints of the internal 38 of the wind turbine blade 20, the width W of each vibration damping device 90 can be varied. For example, as FIG. 8A As shown, multiple vibration damping devices 90 located on the inner layer 42 between the trailing edge 30 and the trailing edge shear web 52 of the outer shell 32 may each have a width W of four resonant units 92. Multiple 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 resonant units 92. And multiple 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 resonant units 92. In one embodiment, for example, the base member 94 and the top member 96 of the vibration damping device 90 may be slightly curved to accommodate the curvature of the inner layer 42 of the wind turbine blade 20. For this purpose, the gap 98 defined by each resonant unit 92 may be of a generally trapezoidal shape.

[0089] like FIG. 8CAs shown, one or more vibration damping devices 90 can be attached to other interior surfaces of the wind turbine blade 20. In this regard, the base member 94 of each vibration damping device 90 can be adhered to the shear web 52 of the wind turbine blade 20. As shown, one or more vibration damping devices 90 can be attached to the interior-facing surface 76 of the web structure 58. In particular, one or more vibration damping devices 90 can be arranged in parallel strips that are spaced apart in the spanwise S direction along the length of the web structure 58 of the shear web 52. To this end, each vibration damping device 90 can 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 device 90 can be generally perpendicular to the chordwise C direction of the blade 20. Depending on the dimensional constraints of the shear web 52 of the wind turbine blade 20, the width W of each vibration damping device 90 can vary. For example, as shown, the plurality of vibration damping devices 90 located on the trailing edge shear web 52 can each have a width W of four resonant cells 92. The plurality of vibration damping devices 90 located on the main shear web 52 can each have a width W of three resonant cells 92. To this end, the width W of the vibration damping devices 90 can vary along the length of the wind turbine blade 20. For example, the width W of each vibration damping device 90 can be greater near the root end 24 of the blade 20 as compared to the tip end 26. FIG. 8C As shown, the plurality of vibration damping devices 90 located on the trailing edge shear web 52 can each have a width W of four resonant cells 92. The plurality of vibration damping devices 90 located on the main shear web 52 can each have a width W of three resonant cells 92. To this end, the width W of the vibration damping devices 90 can vary along the length of the wind turbine blade 20. For example, the width W of each vibration damping device 90 can be greater near the root end 24 of the blade 20 as compared to the tip end 26.

[0090] Referring now to FIG. 8D , a vibration damping module 110 according to an embodiment of the present application is shown. The vibration damping module 110 includes a plurality of vibration damping devices 90 arranged on a substrate 112. The substrate 112 can be corrugated and configured to be attached to a surface of the wind turbine blade 20, such as the inner layer 42 of the wind turbine blade 20 or the interior-facing surface 76 of the web structure 58, to facilitate installation of the plurality of vibration damping devices 90. That is, instead of individually installing each vibration damping device 90 to a surface of the wind turbine blade 20, a single vibration damping module 110 can instead be installed. The substrate 112 can be adhered to the surface of the wind turbine blade 20 and the installation of the vibration damping module 110 installs all of the included vibration damping devices 90 to the wind turbine blade 20.

[0091] With continued reference to FIG. 8DMultiple vibration damping devices 90 can be bonded to a substrate 112. In this respect, the substrate 112 may be corrugated and define multiple generally C-shaped channels 114 extending along the length of the substrate 112 measured between a first end 116 and an opposite second end 118. The vibration damping devices 90 can be arranged on the substrate 112 such that the width W of each vibration damping device 90 can be approximately perpendicular to the channel 114. In this respect, the vibration damping devices 90 can be spaced apart along the length of the substrate 112. The base member 94 of each vibration damping device 90 has multiple trapezoidal protrusions 120. The protrusions 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 protrusions 120 are configured to be received within each channel 114, thereby facilitating attachment of the vibration damping device 90 to the substrate 112.

[0092] FIG. 8E A vibration damping module 110 according to another embodiment of the present invention is shown. As shown, a plurality of vibration damping devices 90 may be arranged on a substrate 112 such that the width W of each vibration damping device 90 is aligned with a channel 114. In this respect, a protrusion 120 on the base member 94 of each vibration damping device 90 extends along the width W of the vibration damping device 90. FIG. 8E The vibration damping module 110 shown includes three vibration damping devices 90, which are spaced apart along the width of the substrate 112 as measured between a pair of side surfaces 113 of the substrate 112. Therefore, 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 can be varied.

[0093] Now for reference FIGS. 9A-10D The modular resonant section 130 will now be described according to an embodiment of the invention. The modular resonant section 130 can function as described above regarding... FIGS. 1-8E The resonant member 62 has the same function and is configured to dissipate vibrational energy away from the surface of the wind turbine blade 20 to which it is attached. However, as will be described in further detail below, multiple modular resonant segments 130 are configured to join together to form a vibration damping device 132 having multiple resonant units 134. In addition to being formed by multiple modular resonant segments 130, the vibration damping device 132 may also be similar to the above description regarding... FIGS. 8A-8E The vibration damping device 90 is described. The structure of each modular resonant segment 130 can be similar to that described above. FIGS. 1-8E The structure of the resonant component 62 is described.

[0094] FIG. 9A and FIG. 9BA modular resonant section 130 according to one embodiment of the present application is shown. As shown, the modular resonant section 130 includes a base member 136 from which a generally L-shaped resonant member 138 protrudes. In this regard, the modular resonant section 130 can be generally C-shaped. The base member 136 includes a generally flat or plate-like body 140 extending from a first end 142 to an opposite second end 144 of the modular resonant section 130. As shown, the second end 144 of the modular resonant section 130 defines an opening of the generally C-shaped profile of the modular resonant section 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 resonant member 138 can be positioned closer to the first end 142 as compared to the second end 144 of the modular resonant section 130. In particular, the resonant member 138 can be spaced a distance from the first end 142 of the modular resonant section 130 to define a tab 150 extending from the body 140 of the base member 136. The tab 150 can have a thickness that is 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 defining 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 resonant sections 130 are configured to be connected in an end-to-end arrangement to form the vibration damping device 132. In this regard, the tongue 152 of the base member 136 of a first modular resonant section 130 is configured to be received over the tab 150 of the base member 136 of an adjacent second modular resonant section 130 to connect the two modular resonant sections 130 together.

[0095] With continued reference to FIG. 9A and FIG. 9B , the modular resonant section 130 includes a generally L-shaped resonant member 138 protruding upwardly from the base member 136. In particular, the resonant member 138 includes a first leg 154 protruding generally perpendicularly from the upper surface 146 of the base member 136 to a second leg 156. For example, the second leg 156 can define a distal end of the modular resonant section 130. The second leg 156 can be arranged generally 90 degrees relative to the first leg 154 and extends from the first leg 154 in a direction toward the second end 144 of the modular resonant section 130. As shown, the second leg 156 can extend a distance beyond the tongue 152 of the base member 136. For example, the first leg 154 can have a thickness measured between a first side surface 158 and a second side surface 160 that can be similar to the thickness of the body 140 of the base member 136. FIG. 9B ​

[0096] With continued reference to FIG. 9A and FIG. 9B The second leg 156 of the resonant member 138 extends from a first end 162 adjacent the first leg 154 to an opposite second free end 164. As shown, the second leg 156 extends generally parallel to the base member 136 of the modular resonant segment 130. The second leg 156 includes a thickness measured between an upper surface 166 and a lower surface 168 of the second leg 156. The second leg 156 includes a platform 170 formed at the first end 162 and a tongue 172 formed at the second end 164. As shown, the platform 170 can be formed in the upper surface 166 of the second leg 156 and the tongue 172 can be formed as a result of a shoulder formed in the lower surface 168 of the second leg 156. The platform 170 and the tongue 172 can each have a thickness that can be less than the thickness of the second leg 156. As will be described in further detail below, a plurality of modular resonant segments 130 are configured to be connected in an end-to-end arrangement to form a vibration damping device 132. In this regard, the tongue 172 of a first modular resonant segment 130 is configured to be received on the platform 170 of an adjacent second modular resonant segment 130 to connect the two modular resonant segments 130 together.

[0097] Referring now to FIG. 9C and FIG. 9D As briefly described above, a plurality of modular resonant segments 130 are configured to be connected in an end-to-end arrangement to form a vibration damping device 132. As shown in FIG. 9C , a first modular resonant segment 130a, a second modular resonant segment 130b, and a third modular resonant segment 130c are connected together in an end-to-end arrangement (as indicated by directional arrow Al) to form an exemplary vibration damping device 132. The vibration damping device 132 also includes an end segment 178 configured to enclose the open second end 144 of the last modular resonant segment 130 in the series, as will be described in further detail below. With respect to the modular resonant segments 130a-130c, the inclusion of a suffix (such as "a", "b", etc.) is used to indicate the first, second, and third components, respectively, and not to imply any structural distinction.

[0098] As shown, the first end 142b of the second modular resonant segment 130b can be received by the second end 144a of the first modular resonant segment 130a. Specifically, the tongue 152a of the first modular resonant segment 130a can be received over the tab 150b of the second modular resonant segment 130b to form a base joint 174, and the tongue 172a of the first modular resonant segment 130a can be received over the platform 170b of the second modular resonant segment 130b to form a top joint 176, as will be described in further detail below. FIG. 9DThe first end 142a of the first modular resonant segment 130a can be received by the second end 144a of the second modular resonant segment 130b. Specifically, the tongue 152a of the first modular resonant segment 130a can be received over the tab 150b of the second modular resonant segment 130b to form a base joint 174, and the tongue 172a of the first modular resonant segment 130a can be received over the platform 170b of the second modular resonant segment 130b to form a top joint 176, as shown in FIG. 6. The modular resonant segments 130 can be bonded together at each joint 174, 176. This process can be repeated for each modular resonant segment 130 connected in series. In this regard, each pair of connected modular resonant segments 130 forms a resonant cell 134. For example, the first leg 154a of the adjoining second modular resonant segment 130b closes the open second end 144a of the first modular resonant segment 130a to define a resonant cell 134. Each resonant cell 134 defines an open-ended void or channel 180 that extends through the vibration damping device 90. Thus, the vibration damping device 90 can be considered an open-cell device, where the voids 180 are open to the ambient environment, such as the interior 38 of the wind turbine blade 20. FIG. 9D The first end 142a of the first modular resonant segment 130a can be received by the second end 144a of the second modular resonant segment 130b. Specifically, the tongue 152a of the first modular resonant segment 130a can be received over the tab 150b of the second modular resonant segment 130b to form a base joint 174, and the tongue 172a of the first modular resonant segment 130a can be received over the platform 170b of the second modular resonant segment 130b to form a top joint 176, as shown in FIG. 6. The modular resonant segments 130 can be bonded together at each joint 174, 176. This process can be repeated for each modular resonant segment 130 connected in series. In this regard, each pair of connected modular resonant segments 130 forms a resonant cell 134. For example, the first leg 154a of the adjoining second modular resonant segment 130b closes the open second end 144a of the first modular resonant segment 130a to define a resonant cell 134. Each resonant cell 134 defines an open-ended void or channel 180 that extends through the vibration damping device 90. Thus, the vibration damping device 90 can be considered an open-cell device, where the voids 180 are open to the ambient environment, such as the interior 38 of the wind turbine blade 20.

[0099] As briefly described above, the vibration damping device 132 also includes an end segment 178 configured to enclose the open second end 144c of the last modular resonant segment 130c forming the vibration damping device 132. As shown, the end segment 178 includes a resonant member 182 that can be similar in size to the first leg 154 of the resonant member 138 of the modular resonant segments 130. The resonant member 182 extends from a base end 184 to a distal end 186. The base end 184 includes a tab 188 that can be similar in size to the tab 150 of the base member 136 of the modular resonant segments 130. As shown in FIG. 6, the end segment 178 is configured to enclose the open second end 144c of the last modular resonant segment 130c forming the vibration damping device 132. Specifically, the distal end 186 of the end segment 178 can be received in engagement with the tongue 172c of the third modular resonant segment 130c to form a first end joint 190, and the tongue 152c of the third modular resonant segment 130c can be received over the tab 188 of the end segment 178 to form a second end joint 192, as shown in FIG. 6. The end segment 178 can be bonded to the resonant segment 130c at each joint 190, 192. FIG. 9C As briefly described above, the vibration damping device 132 also includes an end segment 178 configured to enclose the open second end 144c of the last modular resonant segment 130c forming the vibration damping device 132. As shown, the end segment 178 includes a resonant member 182 that can be similar in size to the first leg 154 of the resonant member 138 of the modular resonant segments 130. The resonant member 182 extends from a base end 184 to a distal end 186. The base end 184 includes a tab 188 that can be similar in size to the tab 150 of the base member 136 of the modular resonant segments 130. As shown in FIG. 6, the end segment 178 is configured to enclose the open second end 144c of the last modular resonant segment 130c forming the vibration damping device 132. Specifically, the distal end 186 of the end segment 178 can be received in engagement with the tongue 172c of the third modular resonant segment 130c to form a first end joint 190, and the tongue 152c of the third modular resonant segment 130c can be received over the tab 188 of the end segment 178 to form a second end joint 192, as shown in FIG. 6. The end segment 178 can be bonded to the resonant segment 130c at each joint 190, 192. FIG. 9D As briefly described above, the vibration damping device 132 also includes an end segment 178 configured to enclose the open second end 144c of the last modular resonant segment 130c forming the vibration damping device 132. As shown, the end segment 178 includes a resonant member 182 that can be similar in size to the first leg 154 of the resonant member 138 of the modular resonant segments 130. The resonant member 182 extends from a base end 184 to a distal end 186. The base end 184 includes a tab 188 that can be similar in size to the tab 150 of the base member 136 of the modular resonant segments 130. As shown in FIG. 6, the end segment 178 is configured to enclose the open second end 144c of the last modular resonant segment 130c forming the vibration damping device 132. Specifically, the distal end 186 of the end segment 178 can be received in engagement with the tongue 172c of the third modular resonant segment 130c to form a first end joint 190, and the tongue 152c of the third modular resonant segment 130c can be received over the tab 188 of the end segment 178 to form a second end joint 192, as shown in FIG. 6. The end segment 178 can be bonded to the resonant segment 130c at each joint 190, 192.

[0100] Referring to FIG. 6, FIGS. 10A-10DFor example, the base member 136 and the second leg 156 of the resonant member 138 of each modular resonant section 130 forming the vibration damping device 132 can be slightly curved or arcuate to accommodate the curvature of the surface of the wind turbine blade 20. The process for assembling the modular resonant members 130 together to form the vibration damping device 132 can be the same as described above with respect to FIG. 9C and FIG. 9D However, as shown in FIG. 10D the resulting void 180 defined by each resonant cell 134 can be generally trapezoidal in shape.

[0101] Turning now to FIG. 11A and FIG. 11C , a plurality of vibration damping devices 132 are shown mounted 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 this regard, each resonant cell 134 can be generally box-shaped. The vibration damping device 132 further includes a width W and a length L between a first end 196 and a second end 198, as shown in FIG. 11A and FIG. 11B For example, the width W of each vibration damping device 132 can be represented by the width of the resonant cell 134. In this regard, the width W of the vibration damping device 134 can be one, two, three, four, or more resonant cells 134. As shown, each vibration damping device 134 can be elongated in the width W direction. That is, the width W of the vibration damping device 134 can be greater than the length L of the vibration damping device 134.

[0102] As shown in FIG. 11A , one or more vibration damping devices 90 can be attached to the interior surface of the wind turbine blade 20. In this regard, the base member 136 of each modular resonant section 130 forming the vibration damping device 134 can be bonded to the inner layer 42 of the shell 32 of the blade 20. As shown, one or more vibration damping devices 134 can be attached to the inner layer 42 at a location along the trailing edge 30 between the trailing edge shear web 52 and the main shear web 52 and / or the main shear web 52 and the leading edge 28 or any combination thereof. To this end, the vibration damping device 134 can be disposed 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. 11A , the vibration damping devices 134 can be disposed in parallel strips that can be spaced apart in the spanwise S direction along the length of the wind turbine blade 20. To this end, each vibration damping device 134 can be disposed such that the width W of the vibration damping device 134 extends in the chordwise C direction of the wind turbine blade 20.

[0103] Depending on the dimensional constraints of the interior 38 of the wind turbine blade 20, the width W of each vibration damping device 134 can vary, for example, by adding or removing modular resonant sections 130. For example, as shown in FIG. 11A the plurality of vibration damping devices 134 on the inner layer 42 between the trailing edge 30 and the trailing edge shear web 52 of the shell 32 can each have a width W of four resonant cells 134 formed by four modular resonant sections 130 and one end section 178. The plurality of vibration damping devices 134 on the inner layer 42 between the trailing edge shear web 52 and the main shear web 52 can each have a width W of three resonant cells 134. And the plurality of vibration damping devices 134 on the inner layer 42 between the main shear web 52 and the leading edge 28 can each have a width W of two resonant cells 134.

[0104] As shown in FIG. 11C one or more vibration damping devices 134 can be attached to other interior surfaces of the wind turbine blade 20. In this regard, one or more vibration damping devices 134 can be adhered to the shear webs 52 of the wind turbine blade 20. As shown, one or more vibration damping devices 134 can be attached to the interior-facing surfaces 76 of the web structures 58. In particular, one or more vibration damping devices 134 can be arranged in parallel strips that can be spaced apart in the spanwise S direction along the length of the web structures 58 of the shear webs 52. To this end, each vibration damping device 134 can 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 device 134 can be generally perpendicular to the chordwise C direction of the blade 20.

[0105] Reference is now made to FIGS. 12A-12I , which shows a vibration damping device 122 according to another embodiment of the present application. In this regard, like reference numerals represent like features as compared to the embodiments of the vibration damping devices 60, 90, 132 described above with respect to FIGS. 1-11C The main difference between the vibration damping device 122 of the present embodiment and the vibration damping devices 60, 90, 132 of the previously described embodiments is that the vibration damping device 122 can be arranged as a ring or ring-like vibration damping device.

[0106] Reference is made to FIG. 12A and FIG. 12BThe vibration damping device 122 includes a plurality of resonant members 62 connected together to form a plurality of resonant units 92. Specifically, the plurality of resonant members 62 may be spaced apart along a common base member 94, with an attachment end 68 of each resonant member 62 engaging or integrated with the common base member 94. The distal end 70 of each resonant member 62 may engage or integrate with a common top member 96. In this respect, the resonant members 62, the top member 96, and the base member 94 may be formed together as an integral part of the vibration damping device 122. However, in an alternative embodiment, the vibration damping device 122 may be formed from a plurality of connected modular resonant segments 130. In either case, each of the plurality of resonant units 92 defines a gap or channel 98 extending through an end opening of the vibration damping device 122. As shown, the vibration damping device 122 includes a length L corresponding to the length L of each resonant member 62 (e.g., FIG. 12B ).

[0107] As shown, the vibration damping device 122 can be attached to the inner surface of the wind turbine blade 20, and specifically to the inner surface at the root end 24 of the wind turbine blade 20. In this respect, 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 device 122 can be located within the interior 38 of the root end 24 of the blade 20. The base member 94, which can form the radial outer ring of the annular vibration damping device 122, can be bonded to the inner layer 42 of the outer shell 32. The top member 96 can form the radial inner ring of the annular damping device 122. In this respect, the vibration damping device 122 extends radially inward from the inner layer 42 to a height H. The height H of the vibration damping device 122 can approximately correspond to the height H of the plurality of resonant members 62. FIG. 12B As shown, multiple vibration damping devices 122 can be arranged as coaxial rings or belts, which are spaced apart along the spanwise S direction along the length of the wind turbine blade 20.

[0108] FIG. 12C A ring vibration damping device 122 according to another embodiment of the present invention is shown. As shown, with FIG. 12B Compared to the diagram shown, the width W of the vibration damping device 122 can be larger. For example, the width W of the vibration damping device 122 can be varied to dissipate vibration energy at different frequencies. FIG. 12D As shown, the spacing of the vibration damping devices 122 along the spanwise S direction of the wind turbine blade 20 122 can also be varied. In one embodiment, as... FIG. 12E As shown, the vibration damping device 122 may have a width W that extends to most of the spanwise length S of the root end 24 of the wind turbine blade 20. In this respect, only one vibration damping device 122 may be attached to the root end 24 of the wind turbine blade 20.

[0109] FIG. 12F A vibration damping device 124 according to another embodiment of the present application is shown. In this regard, like reference numerals refer to like features as compared to the embodiments of the vibration damping device 122 described above FIGS. 12A-12E with respect to the vibration damping device 122 described above. However, as compared to the previously described vibration damping device 122, the vibration damping device 124 of this embodiment can be semi-circular in shape, similar to a half-moon or crescent shape. In this regard, the vibration damping device 124 extends in a curved manner from the first end 100 to the second end 102 to define a semi-circular shape. To this end, the vibration damping device 124 can extend for any portion of the entire circumference of the root end 24 of the blade 20.

[0110] As shown in FIG. 12G one or more vibration damping devices 122 can be attached to other surfaces of the wind turbine blade 20. In this regard, the vibration damping device 122 can be attached to the outer surface of the wind turbine blade 20 and, in particular, to the outer surface at the root end 24 of the wind turbine blade 20. As shown, one or more vibration damping devices 122 can be attached to the outer layer 44 of the outer shell 32 of the blade 20. The base member 94, which can form the radially inner ring of the annular vibration damping device 122, can be bonded to the outer layer 44 of the outer shell 32. The top member 96 can form the radially outer ring of the annular damping device 122. In this regard, the vibration damping device 122 extends a height H in a radially outward direction from the outer layer 44. Multiple vibration damping devices 122 can be arranged in coaxial rings or bands that can be spaced apart in the spanwise S direction along the length of the wind turbine blade 20.

[0111] FIG. 12H An annular vibration damping device 126 according to another embodiment of the present application is shown. In this regard, like reference numerals refer to like features as compared to the embodiments of the vibration damping device 122 described above FIGS. 12A-12E with respect to the vibration damping device 122 described above. However, as compared to the previously described vibration damping device 122, the thickness T of the plurality of resonant members 62 can vary. As shown, for example, the thickness T of the plurality of resonant members 62 can be greater than the thickness T shown in FIG. 12A Accordingly, FIG. 12H the resonant members 62 of the vibration damping device 126 shown in

[0112] FIG. 12I An annular vibration damping device 128 according to another embodiment of the present application is shown. In this regard, like reference numerals refer to like features as compared to the embodiments of the vibration damping device 122 described above FIGS. 12A-12ECompared to the previously described embodiment of the vibration damping device 122, the same reference numerals denote the same features. However, compared to the previously described vibration damping device 122, the thickness T of the base member 94 and the thickness T of the top member 96 can be varied. As shown, for example, the thickness T of the base member 94 and the thickness T of the top member 96 can be greater than [a certain value]. FIG. 12A The thickness T shown is used. In an alternative embodiment, only the thickness T of the base member 94 or the thickness T of the top member 96 can be changed. In either case, by increasing the thickness T of the base member 94 and the thickness T of the top member 96, the size of the void or channel 98 of each resonant unit 92 can be changed, for example, it can be made smaller.

[0113] Now for reference FIG. 13A This illustrates a modular resonant segment 200 according to another embodiment of the invention. In this respect, it is consistent with the above description regarding... FIGS. 9A-11C Compared to the described embodiment of the modular resonant segment 130, the same reference numerals denote the same features. The main difference between the modular resonant segment 200 of this embodiment and the modular resonant segment 130 of the aforementioned embodiment lies in the construction of the resonant member 202. For this purpose, multiple modular resonant segments 200 are configured to be joined together to form a vibration damping device 204 having multiple resonant members 202.

[0114] like FIG. 13A As shown, the modular resonant segment 200 includes a base member 136, from which a resonant member 202 protrudes. The resonant member 202 protrudes from the base member 136 to a free distal end 206. In this respect, the resonant member 200 can be similar to the above description regarding... FIGS. 1-7B The resonant component 62 is described. The construction of the base component 136 of each modular resonant segment 200 can also be similar to that described above. FIGS. 1-7B The construction of the resonant member 62 is described. The base member 136 includes a generally flat or plate-like body 140 extending from a first end 208 of the modular resonant segment 200 to an opposing second end 210. 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 resonant member 138 can be positioned closer to the first end 208 than the second end 210 of the modular resonant segment 200. Specifically, the resonant member 202 can be spaced apart from the first end 208 of the modular resonant segment 200 to define a tab 150 extending from the body 140 of the base member 136. The thickness of the tab 150 can 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 the tongue 152.

[0115] Referring to FIG. 14A , according to one embodiment of the present application, a plurality of modular resonant sections 200 are configured to be connected in an end-to-end arrangement to form a vibration damping device 204. Alternatively, the vibration damping device can be formed as a unitary piece. While the vibration damping device 204 can be annular, it should be understood that the modular resonant sections 200 can be connected together to form a vibration damping device that is non-annular or non-circular. In any case, the tongue 152 of the base member 136 of a first modular resonant section 130 is configured to be received over the tab 150 of an adjacent second modular resonant section 130 to connect the two modular resonant sections 130 together. In this regard, the tongue 152 of a first modular resonant section 200 can be received over the tab 150 of a second modular resonant section 200 to form a base joint 174. The vibration damping device 204 can be formed by repeating this process to connect each modular resonant section 200 in series. In the illustrated embodiment, the modular resonant sections 200 can be connected consecutively to form an annular or ring-shaped vibration damping device 204. In this regard, the bodies 140 of the connected modular resonant sections 200 define a uniform base member 212 that can be bonded to the surface of a wind turbine blade 20. In particular, the vibration damping device 204 can be positioned within the interior 38 of the root end 24 of a wind turbine blade 20. As shown, the vibration damping device 204 can be attached to the interior surface of the root end 24 of the blade 20 and, in particular, to the inner layer 42 of the shell 32 of the blade 20. As a result, the plurality of resonant members 202 extend circumferentially around the root end 24 of the wind turbine blade 20 to form the vibration damping device 204, which is an annular ring of resonant members 202. However, the vibration damping device 204 can be attached to various other locations on the wind turbine blade 20, including both the interior and exterior surfaces of the wind turbine blade 20.

[0116] Referring now to FIG. 13B and FIG. 14B , a modular resonant section 220 according to another embodiment of the present application is shown. In this regard, like reference numerals indicate like features as compared to the embodiment of the modular resonant section 200 described above with respect to FIG. 13A and FIG. 14A . The primary difference between the modular resonant section 220 of the present embodiment and the modular resonant section 200 of the preceding embodiment is that the modular resonant section 220 includes a protrusion 222 at the free distal end 206. The protrusion 222 can be cylindrical, having a circular cross-sectional shape. The protrusion 222 can include a mass, void, or be formed of a different material than the rest of the resonant member 202. As FIG. 14BAs shown, the process for assembling the modular resonant members 222 together to form the vibration damping device 224 can be the same as described above with respect to FIG. 13A and 14A The vibration damping device 224 is shown attached to the inner surface at the root end 24 of the blade 20, and specifically to the inner layer 42 of the shell 32 of the blade 20. However, the vibration damping device 224 can be attached to various locations, including both the inner and outer surfaces of the wind turbine blade 20.

[0117] FIG. 15A An annular vibration damping device 230 according to another embodiment of the present application is shown. In this regard, like reference numerals refer to like features as compared to the embodiment 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 can form a radially outer ring of the annular vibration damping device 230, and a top member 96, which can form a radially inner ring of the annular vibration damping device 230. The vibration damping device 230 further includes a plurality of resonant members 232 extending between the base member 94 and the top member 96. Specifically, each resonant member 232 extends from the base member to a distal end 234. The distal ends 234 of each resonant member 232 can be bridged together via the top member 96, which is the distal-most portion of the vibration damping device 230 relative to the surface of the wind turbine blade 20. As shown, pairs of resonant members 232 intersect to form a plurality of X-shaped resonant cells 236. Each resonant cell 236 defines an upper void or channel 238 and a lower void or channel 240. A plurality of central voids or channels 242 can be formed between adjacent resonant cells 236. As shown, the vibration damping device 230 can be attached to the inner surface at the root end 24 of the blade 20, and specifically to the inner layer 42 of the shell 32 of the blade 20. However, the vibration damping device 230 can be attached to various locations, including both the inner and outer surfaces of the wind turbine blade 20. The configuration of the parts of the annular vibration damping device 230 can be similar to that of the resonant members 62 described above with respect to FIGS. 1-7B

[0118] FIG. 15B ​An annular vibration damping device 250 according to another embodiment of the present application is shown. As shown, the vibration damping device 250 includes an annular body 252 defining a radially outer surface 254 and a radially inner surface 256. Formed in the body 252 can be a plurality of tear-drop shaped voids or channels 258 extending in a widthwise direction through the body 252 of the vibration damping device 250. The voids 258 can be spaced apart around the circumference of the body 252 of the vibration damping device 250 to define a plurality of resonant members 260. Each resonant member 260 extends from the radially inner surface 256 to a distal end 262. The distal end 262 of each resonant member 260 can be bridged together at the radially inner surface 256. Each void 258 includes a bulbous end 264 on one side and a pointed or narrow end 266 on an opposite side. The bulbous end 264 can be positioned adjacent the radially outer surface 254 of the body 252 and the narrow end 266 can be positioned adjacent the radially inner surface 256. As shown, the vibration damping device 250 can be attached to the inner surface at the root end 24 of the blade 20 and, in particular, to the inner layer 42 of the shell 32 of the blade 20. However, the vibration damping device 250 can be attached to various locations including both the inner and outer surfaces of the wind turbine blade 20.

[0119] While the application 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 that the application be limited or limited to the details of the embodiments. Additional modifications will readily occur to those skilled in the art. The various features of the application can 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) together defining 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 emissions from the wind turbine blade (20), the at least one vibration damping device (60, 90, 122, 124, 126, 128, 132, 204, 224, 230, 250) comprising at least one resonant member (62, 138, 202, 232, 260) extending from a surface of the wind turbine blade (20) to a distal end (70, 96, 156, 186, 206, 234, 262), the at least one resonant member (62, 138, 202, 232, 260) being configured to oscillate to dissipate vibrational energy away from the surface of the wind turbine blade (20). 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 from which the at least one resonant member (62, 138, 202, 232, 260) extends from is an interior surface of the wind turbine blade (20).

2. A wind turbine blade (20) according to claim 1, wherein, The interior surface is located on the at least one shear web (52).

3. A wind turbine blade (20) according to claim 2, wherein, The interior surface is located on the first opposing half shell portion (34) or the second opposing half shell (36).

4. A wind turbine blade (20) according to claim 2, wherein, The at least one resonant member (62) comprises a core (78) and an outer skin (80).

5. A wind turbine blade (20) according to any of the preceding claims, wherein, The core (78) comprises a resilient core material and a mass (84) located proximate to the distal end (70) of the at least one resonant member (62).

6. A wind turbine blade (20) according to claim 5, wherein, ​ 7. A wind turbine blade (20) according to any of claims 2 to 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), 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 spaced apart and separately attached to an inner surface of the wind turbine blade (20).

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

9. A wind turbine blade (20) according to claim 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 vibration energy frequencies of different frequency bands.

10. A wind turbine blade (20) according to any one of claims 2 to 9, wherein, The at least one resonant member (62) is an elongated fin extending a length in the spanwise direction along the surface of the wind turbine blade (20).

11. A wind turbine blade (20) according to any of the preceding claims, wherein, The at least one resonant member (62) comprises a height measured between a first end attached to an inner 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. A wind turbine blade (20) according to claim 11, wherein, The first side surface (72) and the second side surface (74) of the at least one resonant member (62) are substantially planar.

13. A wind turbine blade (20) according to any of the preceding claims, wherein, The cross-section of the at least one resonant member (62) is wavy.

14. A wind turbine blade (20) according to any of claims 11 to 13, wherein, The height of the at least one resonant member (62) varies along the length of the at least one resonant member (62).

15. A wind turbine blade (20) according to 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 from which the at least one resonant member (62, 138, 202, 232, 260) extends is an outer surface of the wind turbine blade (20).

16. A wind turbine blade (20) according to claim 15, wherein, The outer surface is located on the first opposing half shell portion (34) or the second opposing half shell portion (36).

17. A wind turbine blade (20) according to 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 a root end (24) of the wind turbine blade (20).

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

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

20. A wind turbine blade (20) according to any one of claims 18 or 19, wherein, The plurality of resonant members (62, 138, 232) are bridged together at each distal end (70, 156, 234) to form a plurality of resonant cells (92, 134, 236).

21. A wind turbine blade (20) according to 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 a first third of a length of the wind turbine blade (20) measured from the root end (24).

22. A wind turbine (10) comprising a wind turbine blade (20) according to any one of the preceding claims.

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