EFFECTS OF A VIBRATION MASS DAMPER IN A WIND TURBINE TOWER

The problem of reducing the dynamic response, and thus the fatigue loa d, on a wind turbine tower is treated by introducing a mass damper. In vestigations are performed using structural optimization on equivalent conditions with and without the damper. Overall effects are analyzed and valuable information is obtained through sensitivity analysis of t he optimal designs. The majority of the paper concerns response modeli ng of the rotor and turbine tower. The load from the rotor is obtained as a deterministic rotor load, determined as the sum of aerodynamic f orces from the static wind field, gravity, and centrifugal forces, and a stochastic rotor load from a randomly fluctuating wind turbulence c omponent. Response analysis of the turbine tower under operational and extreme conditions is outlined and damping contributions, including t he mass damper, are described. Response modeling and structural optimi zation are performed on a VESTAS V39 40 m high 500 kW pitch regulated three-blade horizontal wind turbine. The effect of the mass damper on the response and a sensitivity analysis are presented. It is concluded that the introduction of the mass damper may result in somewhat more economic designs with significantly increased confidence over traditio nal designs.