A comparative study on the fatigue life of mooring systems for a Wave Dragon (WEC)

In this paper, two different types of the mooring system for a wave dragon which is assumed to be installed in south coast waters of Chabahar, Iran are compared. One system consists of one mooring lines and another one consists of two mooring lines. It is considered that the total mass of two systems is the same. The two mooring systems are analyzed from the viewpoint of the fatigue life.The significant wave height of Chabahar for 30 year return period is used. Mooring tension process is obtained from time-domain motion analysis using ANSYS/AQWA, while the rain flow method is used to count the cycle of load and the Miner‟s rule implemented for calculation of fatigue life. The results show that the however the maximum tension on single point mooring is slightly different from the two line mooring system but the fatigue life of single point mooring is about twice bigger than the two line mooring system.

Keywords:

Fatigue , Mooring Chain , Wave Load