Vibratory Load Reduction on a Quad-Rotor Wind Turbine Using Tuned Mass Dampers

This study investigates the impact of tuned mass dampers (TMDs) in reducing vibratory loads on the support structure of a quad-rotor wind turbine. Simulations analyze baseline and turbine models with added TMDs, emphasizing on TMD tuning for optimal response. A high mass (10% nacelle mass) effectively reduces vibratory loads at the rated speed, diminishing at lower wind speeds. For a flexible tower, a notable reduction is achieved in boom root bending moment (RMS value between 87% - 71%) at the rated speed, decreasing to 20-30% at lower wind speeds. Considering tower and boom shadow, overall TMD reduction ranges from 51% to 60% in boom root bending moment or 47% to 52% in boom root Damage Equivalent Loadings (DELs). While TMDs effectively cancel 3p rotor loads, higher frequency loads from shadow remain unaffected. Moreover, during turbulent conditions, tuned mass dampers demonstrate partial load reduction, achieving a 8.8% Damage Equivalent Load reduction at a turbulence intensity of 10% and 18.1% at a turbulence intensity of 12%.