Rotor blade for a wind energy turbine
The rotor blade for a wind energy turbine comprising a longitudinal shell defining a root to be connected to a hub of a rotor, a tip, a forward edge and a rearward edge, the shell having a spar including two spar caps connected via at least one shear web arranged between the forward and rearward edges of the shell and extending in the longitudinal direction of the shell, and a structural damping system arranged within the shell and having a pendulum including a dumped sandwich beam and a mass element located at one end of the beam. The beam comprises a sandwich structure including at least three layers comprising at least one damping middle layer arranged between and connected to outer layers of an elastic material. The sandwich beam is connected to the at least one shear web in a cantilevered manner such that the mass element is proximal to the tip of the shell and the beam can be oscillated in a direction towards and away from the forward and rearward edges of the shell.
1. A rotor blade for a wind energy turbine, comprising
a longitudinal shell defining a root that connects to a hub of a rotor, a tip, a forward edge and a rearward edge, the shell having a spar including at least one shear web arranged between the forward and rearward edges of the shell and extending in the longitudinal direction of the shell,
a vibration damper arranged within the shell and having a pendulum including a beam and a mass element located at one end of the beam,
the beam comprising a sandwich structure including at least three layers comprising at least one damping middle layer arranged between and connected to outer layers of an elastic material, and
the beam is connected to the at least one shear web in a cantilevered manner such that the mass element is proximal to the tip of the shell and the beam can be oscillated between the forward and rearward edges of the shell.
2. The rotor blade according to claim 1 , wherein the at least one middle layer of the sandwiched cantilever beam comprises a viscoelastic, elastomeric or frictional material.
3. The rotor blade according to claim 1 , further comprising bump stoppers arranged within the shell for damping a potential contact of the mass element of the pendulum with the shell.
4. The rotor blade according to claim 1 , wherein the outer layers of the sandwiched cantilever beam comprise metal.
5. The rotor blade according to claim 4 , wherein the metal is steel.
6. The rotor blade according to claim 1 , wherein the sandwiched cantilever beam is fastened to the at least one shear web of the spar of the shell.
7. The rotor blade according to claim 6 , wherein the sandwiched cantilever beam is fastened to the at least one shear web by means of fastening bolts extending through the at least one shear web of the spar of the shell and through the beam.
8. The rotor blade according to claim 6 , wherein the sandwiched cantilever beam is laminated and glued to the at least one shear web by means of integrated lamination and fixtures extending through the at least one shear web of the spar of the shell and through the beam.