Fitness-for-purpose assessment of cracked offshore wind turbine monopile

In this paper, the procedure for flaw acceptability assessment is examined through a case study of semi-elliptical surface crack in an offshore monopile as it grows till forms thickness crack. Using prescribed industrial standard (BS 7910), fracture ratio, Kr shown to increase monotonically with increasing depth. The load Lr, initially insensitive However, there rapid Lr when depth ratio exceeds 80%. values obtained from detailed 3D FE limit analysis using elastic-perfectly-plastic material behaviour do not exhibit asymptotic predicted by BS 7910 transitions deep through-thickness Furthermore, be over-estimation typical dimensions monopiles. findings suggest that structure may identified unacceptable based on still possess non-trivial amount structural residual life. This concern monopiles where growth large significant part total