Steady Response Of Multi-Leg Moorings By Direct Integration

In the design and analysis of multi-leg mooring systems, it is significant, but difficult, to determine the tensions in the mooring legs. The analysis is complicated primarily because of the nonlinear behavior of the cables. The equilibrium equations of the moored body are indeterminate if the number of mooring legs is more than the number of unconstrained degrees of freedom being considered at the moored body. In the presence of spatially variable sub-surface currents, it is generally not appropriate to approximate the cable behavior by catenary equation, as the current-induced drag forces are both positionand orientation-dependent. A method based on direct spatial integration will be demonstrated for the nonlinear static analysis of three-dimensional multi-leg mooring system response to steady currents. This method is well-suited for use on microcomputers.