Proposal of Wear Estimation Method for Mooring Chain of Floating Structures

Up to now, wear estimation method for mooring chain of floating facilities has not been established, and it currently relies on empirical methods. In this research, numerical analysis combining 1) wear analysis between links by finite element method and 2) response analysis of mooring system was performed to establish a method for estimating wear amount of mooring chain during operation. The validity of the proposed method was confirmed by comparing with the actual measurement value in the actual sea area. As a result, it was found that the wear amount estimated by our proposed method is generally close to the measured value. However, it was also confirmed that the estimated wear amount at the touchdown point between the seabed and mooring chain was considerably overestimated. That result could be attributed to insufficient consideration of the effects caused between the links ( e.g. snap load, elastic deformation and friction), the behavior of the links ( e.g. sticking, rolling and non-contact) and the external forces ( e.g. wind and current ).