Modeling and Numerical Simulation of Semitensioned Mooring Line under Taut-Slack State

In this paper, considering the mooring system can be taut-slack in the motion, the dynamic equations of the mooring system are derived by using the theory of large deformation. +e nonlinear dynamic response of semitensioned mooring line is numerically simulated. Assuming the platform motion is known, the e4ect of platform on mooring line is simpli5ed as an end-point excitation. Directly using the 5nite di4erence method for numerically solving partial di4erential equations of mooring line, the dynamic responses can be obtained. +en, the causes about the nonlinear state are analyzed, and the location where the taut-slack phenomenon occurs can be located by calculating the tension of mooring. +e results show that the mooring line is more likely to be taut-slack under tangential excitation with the tension change, while the mooring remains taut under normal excitation. +e taut-slack state of the mooring line is concentrated near the anchor point. +rough the amplitude-frequency curve and bifurcation point set, it is found that the taut-slack region is accompanied by multiperiod motion. And the taut-slack phenomenon will lead to the unstable motion.