The invention relates to a method for designing a flexible blade or an articulated rigid blade with one or more torsion springs, for a wind turbine or a water turbine, the flexible blade being designed to passively control the pitch angle of the wind turbine or of the water turbine during operation, the method comprising the following steps: a) receiving the known geometric profile; b) determining a change in the optimal pitch angle, 0o opt rigid, as a function of the specific speed ; c) determining the local behaviour of the flexible blade or of the articulated blade and local ratios relating to the aerodynamic loading and to the centrifugal force being exerted on the blade; d) determining local values of the bending modulus B of the flexible blade/the stiffness of the torsion spring and of the mass density p of the blade; and e) providing information relating to the selection of the material.

Methods and devices for accessing a drive train for a wind turbine utilize an elastic coupling. The drive train comprises a rotor shaft configured to be driven by a rotor about a main axis and a support structure including a bearing housing surrounding at least one bearing and supporting the rotor shaft for rotation about the main axis to constrain other movements of the rotor shaft. A gearbox input shaft and housing supports the gearbox input shaft for rotation while constraining other movements of the gearbox input shaft. The gearbox input shaft is coupled to the rotor shaft by an elastic coupling comprising a first coupling part rigidly connected with the rotor shaft, a second coupling part rigidly connected with the gearbox input shaft, and elastic elements positioned between the first and second coupling part to provide a single joint between the rotor shaft and the gearbox input shaft.

Provided is a composite material for a wind turbine blade, the composite material including a plurality of rigid elements and plurality of flexible elements, wherein each flexible element is arranged between two rigid elements and is connected thereto such that the rigid elements are flexibly connected to each other by the flexible elements. The flexibility of the composite material can be achieved by using the interspaces between the rigid elements. Therefore, when the composite material is placed on a curved surface, hollow spaces between the rigid elements may be reduced or avoided.

A wind turbine blade having a structural member is provided including: a first stringer; a second stringer; a rigid tie pivotally secured to the first stringer and pivotally secured to the second stringer; and a tension tie secured to the first stringer and the second stringer and arranged to experience tension during increasing lateral displacement between the first stringer and the second stringer as the wind turbine blade bends in a first direction. Unlike a conventional wind turbine blade truss, the structural member provides nonlinear resistance to bending of the blade.

A plurality of wind turbine blades or blade portions have substantially the same size and outer geometrical shape, and corresponding plies of the blades or blade portions having the same position within the respective wind turbine blades or blade portions have different fibre orientation angles relative to a pitch axis of the respective wind turbine blade or blade portion. By changing the fibre orientation angles of the corresponding plies a bend-to-twist coupling of the blade or blade portions may be varied amongst the plurality of blades or blade portions. The blades may then be tailored according to their siting within or on a wind turbine park. A common mould shape may be used across the plurality of wind turbine blades or blade portions, together with a more streamlined blade design process.

The present invention relates to a gasket adapted for being placed between a transition piece and a monopile of a wind turbine. One embodiment relates to a gasket for formfitting the bottom part of a transition piece of a wind turbine, the gasket primarily manufactured in an elastomeric material and shaped as a hollow elongated body for surrounding at least a part of the monopile when mounted between the transition piece and the monopile, such that the gasket stabilizes the position of the transition piece relative to the monopile. The presently disclosed gasket can substitute the traditional grouting or bolting procedures when mounting a transition piece on a monopile.

A wind turbine blade 2 for a rotor has a longitudinal direction extending from a root region 26 to a blade region. The wind turbine blade 2 is formed of a fibre-reinforced polymer material comprising a polymer matrix and a first and a second reinforcement fibre material being embedded in the polymer matrix. The wind turbine blade further comprises a first region being reinforced predominantly with the first reinforcement fibre material, a second region being reinforced predominantly with the second reinforcement fibre material, and a transition region between the first and the second region. The first region extends in the root region 26 and the first reinforcement fibre material is a metal.

A downhole turbine includes a plurality of fins. The plurality of fins have an exit angle that exerts a tangential force on the fin, which imparts a torque on a hub. The fins have an adjustable exit angle that changes in response to changes in the properties of a drilling fluid. The changing exit angle changes the tangential force, which changes the torque on the hub.

A wave energy converter can be dynamically tuned to achieve resonance with ocean swell by varying the geometry of an attached submerged water-filled vessel (41).

A roll-diaphragm compressor that includes a compressor head with an interface wall that defines a concave portion and with an apex portion having an inlet port and outlet port. The roll-diaphragm compressor can also include a flexible roll-diaphragm coupled to the compressor head about an edge with the roll-diaphragm driven in a rolling motion against the interface wall. The roll-diaphragm compressor can also include a compression chamber defined by the compressor head and roll-diaphragm that is configured for receiving a fluid via the inlet port in a first state, compressing the fluid based on the volume of the compression chamber being made smaller, and expelling the fluid in a second state via the outlet port.