TY - JOUR
ID - 85482
TI - Modeling and Estimation of Fatigue Damage Accumulation in Marine Risers of Fixed Platforms
JO - Journal of Hydraulics
JA - JHYD
LA - en
SN - 2345-4237
AU - Moghiseh, A.
AU - Riahi, H.
AU - Rahi, A.
AD -
Y1 - 2009
PY - 2009
VL - 3
IS - 4
SP - 53
EP - 61
DO - 10.30482/jhyd.2009.85482
N2 - Offshore gas and oil fields are being discovered and exploited nowadays in water depths of more than2000 m. The operation in depths increases the external forces so that the equipments should be moreadvanced and expensive. Fatigue damage accumulation is one of the most important problems aboutmarine structures that are exposed to the alternative loads. Riser is one of these structures. Thesurrounding environment of riser causes alternative stresses and fatigue in riser. To obtaini thesestresses, the analysis of the vortex induced vibration in two direction, in-line and cross flow, isnecessary. The risers are long relative to their cross sections so that the Euler-Bernoulli theory isapplicable for description of the pipe dynamic bending. The flow and riser motion in x direction formsa vortex shedding in front of riser. These vortices cause the drag force in x direction and the lift forcein y direction. These forces are time dependent. The drag force is obtained from Morisonâ€™s formula.The lift force excites the vibration in y direction. After obtaining the equation of motion and solving itby using numerical methods such as Galerkin, finite difference and Runga-Kutta fourth order method,the riser deflection in two directions will be obtained and the stress at the outer diameter of riser willbe calculated. The fatigue damage accumulation in the riser can be obtained by using Shigley theoryand Palmgren-Miner rule.
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L1 - https://jhyd.iha.ir/article_85482_a510b475cb00f1390b74375bfe33f3c7.pdf
ER -