Catenary riser sliding and rolling on seabed during induced lateral movement

Author(s)

Neto, Alfredo Gay ^[1] ; Malta, Eduardo Ribeiro ^[2] ; Pimenta, Paulo de Mattos ^[1]

Affiliation

^[1] Univ Sao Paulo, Polytech Sch, Dept Struct & Geotech Engn, Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Polytech Sch, Dept Naval Arch & Ocean Engn, Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: MARINE STRUCTURES; v. 41, p. 223-243, APR 2015.
• Web of Science Citations: 5

Abstract

Catenary risers have an interaction zone with the seabed, usually referenced as flowline. Movements in this region can be induced by sea currents and large offsets in floating unit, leading to touchdown position changes and affecting internal loads along riser length. In this work the contact flowline-seabed is modeled including sliding and rolling friction. Case studies involving large offsets in floating unit and lateral sea currents are solved to better understand the consequences of possible rolling and large sliding. The riser is modeled using a geometrically-exact finite element beam model. The contact is addressed with a new technique to include rotation movements from underlying beam models. This leads to global riser models including complex kinematics, being able to represent scenarios with alternating sliding/rolling and its consequences on internal loads of riser structure. A parametric study is performed to measure the influence of the friction coefficient in tension and torsion along typical flexible pipe and steel pipe catenary risers. (C) 2015 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 12/09912-0 - RISERS NONLINEAR DYNAMICS INCLUDING THE UNILATERAL CONTACT WITH THE SEABED
• Grantee: Alfredo Gay Neto
• Support Opportunities: Scholarships in Brazil - Post-Doctoral