Analytical estimation of static stress range in oscillating steel catenary risers at touchdown areas and its application with dynamic amplification factors

• An analytical model predicting the static stress range in SCR is proposed.
• Numerical simulations are used to validate the analytical model.
• Sensitivity studies are conveniently performed using this analytical model.

Steel catenary risers (SCRs) are dynamically sensitive structures and their fatigue design in the touchdown zone is challenging. The dynamic response of SCRs is traditionally assessed by performing a series of long time history analyses but a simplifying approach has recently been proposed. The simple method is based on the use of dynamic amplification factors that quantify the dynamic response for a given perturbation at the hang-off point relative to the static response. The determination of the static response of SCRs is therefore a prerequisite to this approach. In this paper, an existing analytical model is extended to accommodate the displacement at the hang-off point of the SCR and predict the static stress range. The results of this analytical model are validated against numerical simulations. Then, using this simple and efficient analytical model, various sensitivity analyses are performed to explore the impact of key dimensionless groups on the static stress range in the touchdown zone.