Static And Wave Induced Fatigue Analysis Of Steel Catenary Riser

Marine riser is the main connector between a platform and the mouth of a well in the seabed. It works in tough environment and its analysis is always the hot topic in offshore oil engineering. By far, the research on shallow-water risers has become mature. However, the one on deep-water risers is just begun with a preliminary step. The loadings on deep-water riser include: wave, current, wind and the movement of the platform which sometimes bring the vibration of the riser induced to the fatigue damage problem.As the design basis, the wave theory in the hydrodynamic is introduced in this paper firstly. And the equations of airy wave and stokes wave are advanced and derived. The calculation methodology of the vertical riser's wave force, the Morison equation which governs the analysis of the wave loading, the theory that how to choose the wave theory, drag coefficient, inertia coefficient, the computation methods of the wave loading which influenced by both wave and current, are recommended.Then, the static analysis of the SCR is implemented by the finite element software ANSYS, which judges whether the riser meets the strength requirement in different drifts. Subsequently, the vibration characteristic and the stress frequency response function are got by the modal and the harmonic analysis of the riser.At last, the fatigue damage per year of the riser when the platform surges or heaves is computed by FORTRAN software which is based on Miner damage rule. Otherwise, the calculation of the riser damage is carried on according to different wave heights and wave periods when platform surges.