Wave-Induced Fatigue Damage Analysis for Submarine Pipeline Span

Based on cumulative damage theory, this paper examines wave-induced fatigue damage of submarine pipeline span under the wave. Constraint-equivalent method is used to deal with the boundary conditions of pipeline span according to the factual seabed supports for the pipeline. The nonlinear vibration equation, which satisfies the given boundary conditions, is set up and its closed form solution is developed. The fatigue damage models are detailed in frequency domain approach. A numerical example is presented to illustrate the technical models, and the effects of relative parameters such as span length, seabed stiffness, and hydrodynamic coefficients to fatigue damage are studied.