Research on smart control tests of ice-induced vibration control of offshore platform

This paper proposes a smart control system to reduce ice-induced motions in the offshore jacket platform structure subjected to ice-induced vibration. Magnetorheological (MR) dampers are applied as smart control devices and the control input determination is based on a clipped-optimal control algorithm which uses absolute displacement and acceleration feedback. The performance of this method is studied experimentally by means of an offshore jacket platform model. The damping isolation layer with rubber supports and MR dampers is designed for 1:10 scale model of JZ20-2MUQ platform structure. Ice-induced vibration control tests have been performed on three models, i.e. the original structure, the structure with rubber bearings and the structure with rubber bearings and MR dampers using one in-situ bending ice and one in-situ compression ice loads. The MR damping control schemes include Passive On, Passive Off and Smart controls. The experimental results indicate that both the pure isolation and MR damping isolation schemes can significantly reduce the response of displacement of the jacket cap and the acceleration of the deck. The MR smart control is better than other two passive controls.