The nonlinear finite element analysis and optimum design to the thread joint of 30 in. marine riser

摘要

Both the method of engineering and nonlinear finite element method have been used to the analysis and optimum design of the 30 in. marine riser with the screw thread. Two load steps have been used in the finite element analysis including the processes of both assembling and applying the load of piling, and the nonlinear contact between marine risers has been considered in the simulation. Numerical results show that the stress in the marine riser increase rapidly when the magnitude of interference of the screw thread change slightly. By the way to change interferential magnitude of the screw thread, the maximum stress of Von Mises decrease from 681MPa to 381MPa and contact stress decrease from 238MPa to 122MPa. The engineering practice over 100 piles in offshore platform has shown that the numerical results are good.