Experimental study on semi-active magnetorheological elastomer based isolation system for offshore platform using wave tank

Abstract

Hydro-dynamic induced vibration is a major risk for offshore platform, which may cause fatigue damdage. The present work experimentally studies a smart isolation system for vibration mitigation of offshore platform utilizing magnetorheological elastomer (MRE). The principle of the proposed MRE-based smart isolation system is presented, in which a real-time decoupling between superstructure (deck) and the jacket structure is achieved by controlling MRE's horizontal stiffness. For a case study, a scaled simplified fixed offshore platform model is built. The prototype of MRE-based isolation system is manufactured and its field-induced dynamic performances are tested. A fuzzy logic controller is proposed for achieving real-time decoupling control. A wave tank testing for the offshore platform with MRE-based isolation system is conducted, in which wave loadings in different dynamic characteristics are considered (e.g., regular and random waves). The results show that the deck acceleration and its displacement, and isolation drift are greatly decreased by the controlled MRE isolation system. It is proven that the smart MRE-based isolation system is able to provide effectiveness vibration suppression for offshore platform structure over a wide range of wave loadings.