Mooring system stiffness: A six-degree-of-freedom closed-form analytical formulation

A mooring system project is an iterative process, involving design and analysis with numerous parameters. In this context, analytical tools can help to reduce the use of expensive time consuming full nonlinear numerical simulations based on high-order hierarchical models such as Finite Element models, mainly during early stages design. By employing Analytical Mechanics approaches, present article brings closed-mathematical-form formulation determine six-degree-of-freedom (DOF) stiffness matrix at any generic position floating body, provided line forces are modeled conservative ones. order demonstrate these tools, international benchmark OC4-DeepCwind platform considered a case study. The influence vessel mean parameters in stiffness, natural periods oscillation modes studied, revealing interesting coupling effects. Results benchmarked against commercial code OrcaFlexTM showing good agreement, observing that result requires much less computational cost.