Fatigue Analysis of Flexible Risers due to Bimodal Waves

摘要

This paper presents a comparison of the various methods for combining bimodal wave fatigue damage for flexible risers attached to floating production platforms. Finite Element Analysis is used to determine the riser response, stress ranges, and fatigue damage. The resulting stress ranges or damages are then combined via the various methods outlined in DNV-RP-F204 [2] and the RealLife JIP [3]. A base case of the fatigue damage with swell and sea analyzed together is compared against each method for summation of the damages to determine the level of conservatism in each method. A recommendation of the most appropriate method of combining swell and sea wave damages is presented in this paper.