Nonlinear coupled analysis for multi-body offshore floating structures

Multi-body floating structures are being widely used in the exploitation of offshore oil and natural gas. Motion response for each single body in multi-body system can be influenced by the others and there is strong nonlinear coupling effect between them. The coupled system includes a turret moored FPSO and an offloading oil buoy connecting to the FPSO by a flexible offloading oil line. The multi-body model is built to evaluate the vessels motion performance and oil line tension in the design environmental condition by static analysis and coupled analysis in time domain. Meanwhile, the results for single body analysis models are obtained to compare with coupled multi-body model. The analysis result shows that multi-body coupled analysis supplies a more accurate method to evaluate the vessel motion response and the dynamic characteristics of mooring lines and offloading oil line, which could be a reference for the study of system performance and selection of oil line connecting between the two vessels.