Similar approaches have previously been demonstrated, but with significant limitations in stress precision and computational speed. In such simulations, stress levels can be obtained as an integral part of the simulation procedure, or by post-processing the global response time series using a local-global approach where global response to stress transfer functions are generated once through a local analysis with a detailed FE model. However, the armour wire stresses are significantly influenced by such local friction, causing hysteresis effects that influence estimated fatigue life. Segments of flexible risers experiencing large curvatures may respond non-linearly with respect to armour friction behaviour, but the effects on the global displacement responses are minor. This captures the non-linearity in wave and drag loading, and includes geometric non-linear effects, while material behaviour often is assumed linear. Dynamic global displacement response of risers subjected to irregular waves is commonly simulated by time-domain Finite Element methods.
