Influence of Earthquake Directions on Wind Turbine Tower under Seismic Action

Abstract

Influence of earthquake directions on wind turbine tower under seismic action are numerically investigated in this paper. First, equations of motion and an integrated finite element model of a wind turbine system consisting of a rotor, a nacelle and a tower shaft are established. Second, the finite element modal analysis is discussed. Third, relationships between upper displacements in x, y directions and bottom bending stress when the angle is 0, 30, 45, 60, 90 degree respectively between earthquake directions and concentrated eccentric mass direction (x direction) are analyzed by adjusted Taft seismic wave .The results show that: seismic responses of a wind turbine tower are remarkable and seismic action may be the dominant factor in the design of wind turbine towers that located at a seismically active zone. Under different earthquake directions structure’s dynamic responses are different, 90 degree with regard to x direction is the most unfavorable direction. Both maximum upper displacements in x, y directions and bottom bending stress appear at 90 degree direction with regard to x direction.