Double braid mooring damper for floating offshore wind application

Abstract

Introduction of innovative mooring components can reduce the risk and cost associated to mooring systems of floating offshore wind turbines. The Intelligent Mooring System (IMS) is an active, hydraulic, nonlinear mooring component developed by Intelligent Moorings Limited that provides functionality akin to a shock absorber. It offers a combination of desirable stiffness characteristics for floating offshore wind application; an initial compliant response that reduces loads on the structure and a stiffer nonlinear response for larger loads to reduce platform motion and ensure effective station keeping. A salient feature of the IMS is that through variation of the internal pressure, the stiffness of the system can be adjusted in accordance with the prevailing environmental conditions. This paper presents the results of the physical testing of a double braided IMS at the Dynamic Marine Component test facility and compares the stiffness and strength characteristics to a single braid sleeve. The comparative analysis shows that the stiffness profiles of the double braid for the various configurations are consistent with the single braid design. Importantly, the use of a double braid results in a 50% increase of the tensile strength of the IMS. The investigation presented in this paper will aid in the design of a robust IMS for field testing prior to commercial applications in floating wind installations.