VIBRATION CONTROL FOR STEEL TUBULAR TOWERS OF HORIZONTAL AXIS WIND TURBINES

Resumo

This paper analyzes the effectiveness of three types of vibration control, namely, Tuned
Mass Damper (TMD), Active Mass Damper (AMD) and a Hybrid Mass Damper (HMD), applied to a
steel tubular tower, 120 m high, for an onshore Horizontal Axis Wind Turbine (HAWT). For this, the
tower was modeled using beam (own code) and shell and solid finite elements (via ANSYS). In all
cases, the insertion of the control device was idealized at the top of the tower. The theory proposed by
Den Hartog was used to determine the coefficients of the absorber and the Linear Quadratic Regulator
(LQR) was applied to obtain the optimal control variables introduced by the hydraulic actuators. It was
observed a reduction of the root mean square (r.m.s) of displacements of the top of the tower with
control in relation to the without control displacements, when subjected to a harmonic and resonant
action to the first mode of vibration of the uncontrolled structure: 67.78% for the TMD and 71.64%
for the AMD in a transient excitation; 93.87% for the TMD and 95.26% for the AMD in a permanent
excitation. In addition, the effective displacements (r.m.s) with the use of HMD were smaller
compared to the TMD results, presenting a reduction of 26.68% in the transient excitation and 39.46%
in the permanent excitation.