Semi-active control of jacket platforms under wave loads considering fluid-structure interaction

Abstract

Jacket platforms are among the most used offshore platforms for energy extraction from seabed and are prone to failure caused by the inherent dynamic nature of wave loads. Therefore, vibration control of these structures with the goal of enhancing efficiency and preventing structural damage is of outmost importance. In current work, semi-active control of the Ressalat jacket platform using a large-scale magnetorheological (MR) damper with fuzzy logic controller is investigated with the aid of the computationally efficient modified endurance wave analysis (MEWA), considering waves with return periods of 2, 5, 10, 20, 50 and 100 years. The effect of number of dampers, fluid-structure interaction, added mass effects and actuator saturation has been simultaneously implemented in the current study. A total of six performance indices based on maximum and root mean square (RMS) of responses (inter-story displacement, velocity and acceleration) are used to assess the efficiency of the control method for waves with different intensities and return periods. Results of current analyses provide a comprehensive overview of the performance of the MR damper for the semi-active control of the Ressalat jacket platform under different wave loads with different return periods and show an acceptable performance for all the considered wave loads, with the goal of enhanced safety and increased service life.