Fully Stochastic Fatigue Analysis for FPSO Based on Shipyard Practices

摘要

Pending controversies between oil companies and shipyards concerning stochastic fatigue strength analyses for FPSO (floating-production-storage-offloading), one of the representative floaters, are explained based on shipyard practices. Focused on how the issues affect on the spectral fatigue evaluation, the items under discussion are: diversified wave conditions, cases of spectrum combinations, screening methods, CJP welding requirements, fabrication tolerances, overlapping of corrosion margins and Morison loads on slender members. Theoretical reviews are also introduced in calculation sequences of spectral fatigue analysis, where derivation of hotspot stress is discussed in detail. In order to resolve large parts of the issues and requirements from major oil companies, a fully stochastic spectral fatigue analysis program is developed and outstanding features of the program are introduced.