Vortex-Induced Vibration And Fatigue Analysis Of Steel Catenary Riser

With depletion of petroleum on land and in shallow water,petroleum exploration is continuously developing into deep-water.Now Steel Catenary Riser(SCR)is becoming the best choice of riser type in petroleum production.While the marine environment is complex,SCR is easily damaged because of fatigue.Vortex-induced vibration caused by current occupies an important part in SCR fatigue damage among the factors.SCR fatigue damage caused by vortex-induced vibration are analyzed and the main contents are following:(1)Based on the beam element theory,SCR static analysis program is developed.The static sensitivity parameters of SCR are analyzed.In order to provide some guidance for riser design and analysis,the impacts of different current velocity and platform static offset on riser configuration and forces are studied.(2)SCR modal analysis is done.Vibration mode and natural frequencies of SCR are calculated.The impacts of SCR wall thickness,diameter,hanging angle and current velocity onnatural frequency are analyzed.(3)Basing on the results of modal analysis,SCR transverse vortex-induced vibration response is calculated by using modal superposition method.The impacts of riser wall thickness,diameter,hanging angle and current velocity on vortex-induced vibration fatigue damage are focused on and some valuable results are presented.(4)In order to discuss the availability of the model,numerical results of empirical model i.e.wake oscillator modeland test results are compared.Applying the wake oscillato rmodel on SCR and combining the P-y curve,time domain response of riser vortex-induced vibration by considering nonlinear seabed is calculated.