Semi-active control of wind-induced responses of transmission tower-line system by using magnetorheological dampers

The semi-active control of wind-induced vibration of transmission tower-line system by using magnetorheological (MR) dampers is actively investigated in this study. The mechanical model of MR damper is presented by involving the effects of damper's axial stiffness. The multi-degree-of-freedom (MDOF) model of transmission line is developed. The dynamic model and analytical approach of transmission tower-line system incorporated with MR dampers are developed for both in-plane/out-of-plane vibration. Two semi-active control strategies are proposed for the vibration mitigation of tower-line system: one is the strategy based on fixed increment of controllable damper force and the other is a clipped-optimal strategy based on fuzzy control principle. A real transmission tower-line system constructed in southern China is taken as the example to examine the feasibility and reliability of proposed control approach. In addition, the parameter study is carried out in order to examine the effects of load intensity, damper's axial stiffness and parameters of MR fluids on the control performance. The observations demonstrate that the MR damper can be utilized in the wind-induced vibration control of transmission tower-line system because of its simple configuration as well as satisfactory energy-dissipating capacity if the damper parameters are optimally determined.