Floating wind turbine facilities, which are installed in the deep sea area, plays an essential role to promote the green energy application. One of the problems associated with the commercialization of facilities installed in the deep sea is the reduction of the maintenance cost of mooring chain, because breaking of the mooring chain caused by the wear between links leads to enormous economic losses. Therefore, it is necessary to establish a quantitative wear evaluation method for mooring chains. Experimental facility to reproduce the wear caused by sliding between links in actual scale applied for floating wind turbine, which had been proposed by the authors, was updated and the wear tests was conducted by setting some tensile force conditions between the links. Besides, procedure of the nonlinear finite element analysis was improved to estimate the behaviour of wearing between links. From experiments and numerical analysis, it has been confirmed that the tensile force between links is an important factor of the wear amount between links.

Floating wind turbine facilities, which are installed in the deep sea area, play an essential role to promote the green energy application. One of the problems associated with the commercialization of facilities installed in the deep sea is the reduction of the maintenance cost of mooring chain. Therefore, it is necessary to establish a quantitative wear evaluation method for mooring chains. Specific wear is one of the essential physical parameter to evaluate the wear performance of metals. However, detailed investigation of the specific wear of the mooring chain has not been performed yet. The pin-on-disk wear tests were performed to measure the specific wear in the air and in the substitute ocean water. As a result of experiments, it has been confirmed that the specific wear in the substitute ocean water was remarkably smaller than in the air, and the wear state was stable.

To produce offshore wind power generation plants, deep-sea floating wind turbine facilities are required. Commercial installation of floating wind turbine facilities requires a reduction of the mooring cost. Mooring chain breaks due to progressive wear will lead to enormous damages. Therefore, a quantitative wear evaluation method for mooring chains needs to be established. In this study, an experimental setup was constructed to reproduce the wearing phenomenon in mooring chains due to the motion of the floating body induced by waves, and its usefulness was confirmed. The result of the wear test conducted in this study suggests that the tensile force between links affects the degree of wear. Additionally, numerical simulations were performed using a finite element model with measured wear characteristics of the link material to reproduce the phenomenon of wear between links and confirmed that the wear phenomenon could be represented by numerical simulation.