The effects of one mooring line failure on the behavior of a work ship

Abstract

In this paper, the dynamic performance of a work ship with a mooring line failure was studied. A fully coupled dynamic analysis program ANSYS/AQWA was applied to simulate ship motions and mooring line dynamics. The first- and second-order wave excitation forces were calculated using the three-dimensional diffraction/radiation theory, and the behaviors of the mooring lines were analyzed using a nonlinear finite element method. Under the combined environmental loads of waves and wind, one mooring line was intentionally disconnected at a certain moment. Then, the dynamic response after the mooring line breaks, the energy distribution characteristics in the motion response spectrum and the mean tension variation of the remaining mooring lines were discussed. The results showed that a sudden failure of the mooring line significantly affected the performance of the ship. To ensure the structural integrity of the ship system and the safety of personnel on deck, the influence of a mooring line failure on the ship should be investigated in advance.