Abstract
Dynamic umbilicals are usually exposed to cyclic environmental loads
due to waves, motions of the host vessel, and current induced
vibrations. These cyclic loads drive the fatigue design of functional
components such as armor wires, steel tubes and conductor wires in an
umbilical cross section. Fatigue assessment of umbilical components
involves Finite Element Method (FEM) modelling both globally and
locally. The "global" model is used to predict dynamic responses of an
umbilical with equivalent cross-sectional properties in waves and
currents. Stress calculation in umbilical components requires a special
"local" FEM tool such as Uflex2d to correctly capture the interaction
mechanics among the components within the cross-section.
This paper compares three methods for the combination of global and
local analysis in order to obtain fatigue estimates. First method can be
regarded as exact one and is used to benchmark other two, which are
approximate.
due to waves, motions of the host vessel, and current induced
vibrations. These cyclic loads drive the fatigue design of functional
components such as armor wires, steel tubes and conductor wires in an
umbilical cross section. Fatigue assessment of umbilical components
involves Finite Element Method (FEM) modelling both globally and
locally. The "global" model is used to predict dynamic responses of an
umbilical with equivalent cross-sectional properties in waves and
currents. Stress calculation in umbilical components requires a special
"local" FEM tool such as Uflex2d to correctly capture the interaction
mechanics among the components within the cross-section.
This paper compares three methods for the combination of global and
local analysis in order to obtain fatigue estimates. First method can be
regarded as exact one and is used to benchmark other two, which are
approximate.
