Multibody dynamic analysis of float-over installation based on active multi-dimensional motion compensation equipment

Abstract

Float-over technology has been gaining attention for its cost-effectiveness and ability to handle heavier loads. However, wave-induced motions during the installation of offshore platform topsides can pose challenges for the barge and interfere with the load-transferring process. To address this issue, this paper proposes a new active motion compensation equipment (MCE) that can replace the conventional Deck Supporting Unit (DSU) to enhance the load-transferring operation. The study develops a multibody dynamic model of the motion-compensated float-over (MCFO) system and introduces a Jacobian matrix to describe the interaction between the topside and barge due to the MCE's altered connection properties. Numerical simulations are conducted for the specific mating process of MCFO with MCE and DSU equipped, respectively. The analysis considers the motions of the barge and topside, as well as the corresponding loads of the Leg Mating Unit (LMU). Results show that the proposed MCE can compensate for most of the wave-induced motion of the barge, reducing the duration and scale of slamming during load transferring. The proposed MCE can thus improve operational feasibility in harsh sea states and presents a profitable attempt at active compensation mode.