FATIGUE ASSESSMENT OF HULL GIRDER FOR SHIP TYPE FLOATING PRODUCTION VESSELS

For ship type floating production vessels (FPV's) moored at a permanent location in the North Sea or equivalent harsh environments fatigue of the hull girder may be a governing strength criterion, in particular if high tensile steel is used. DnV in cooperation with the Norwegian Institute of Technology are carrying out a research programme to develop design criteria with respect to fatigue of ship hull girder. Different approaches to estimate hull girder fatigue life for FPV's are reviewed and a simplified method calibrated against refined analyses as well as in-service experience with ships has been developed. The simplified approach indicates a certain increase in midship section modulus for FPV's compared to traditional ship classification rules if high tensile steel is used.