Dynamic Response Analysis Of CALM Mooring System

With the development of the offshore oil industry, the extra-tanker is playing an increasingly significant role. The mooring system, which realizes the auxiliary functions of location, oil transportation and communication for the tanker, has become one of the most important facilities in the exploitation of offshore oil. tanker, subjected to wind, wave and current, suffers the minimum force for the effect of single point mooring’s weathercock, thus ensuring its sustained operation at sea for a long time. Therefore, the security of single point mooring system is crucial. In this thesis, AQWA software is used to make a time domain numerical computation of the single point mooring system to analyze its dynamic response. Further discussions of the effect of anchor chain’s layout and composition on the mooring system dynamic response are made.Sea environment loads is the foundation of the design and evaluation of single point mooring system. All the possible environment loads are calculated in this thesis, and the toughest sea condition is considered in the following analysis and assessment. Time domain coupled dynamic analysis method is used to calculate the dynamic behavior of tanker point mooring system, fully considering viscous effects, nonlinear second-order low frequency load, and dynamic characteristics of the mooring lines. Fatigue of the mooring lines is checked. The mooring form and the composition of anchor chain are discussed to get an optimization.The results imply that the dynamic response of the tanker single point mooring system, the anchor chain strength and fatigue life of the anchor chain calculated in this paper meet the requirements of DNV rules. The layout and composition of the anchor chain could be adjusted appropriately by the designer to be economical and practical and ensure that its response meets regulatory requirements. The conclusions of this study can be used as basic for the designers of mooring system to choose the form of mooring lines, to calculate the dynamic response of mooring system.