RISERS NONLINEAR DYNAMICS INCLUDING THE UNILATERAL CONTACT WITH THE SEABED

• Grant number: 12/09912-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: September 01, 2012
• End date: March 31, 2014
• Field of knowledge: Engineering - Civil Engineering - Structural Engineering
• Principal Investigator: Paulo de Mattos Pimenta
• Grantee: Alfredo Gay Neto
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 12/21167-8 - Techniques for the computational analysis of contact problems in risers, BE.EP.PD

Abstract

Risers are structures used for oil exploitation, being modeled as long beams, subjected to their own weight, external and internal pressure loads, sea current and sea wave loads. There is also a nonlinear boundary condition in certain riser configurations, such as catenary and lazy-wave, which consists of a unilateral contact between the riser and the seabed. To analyze these configurations one needs the statics and dynamics, possibly with large displacements and large rotations magnitudes, depending on the type of study and conditions considered. In this context, a nonlinear kinematically-exact beam formulation becomes an attractive choice for modeling a riser, in order to capture the geometric nonlinearities present. Furthermore, the representation of riser-seabed contact interaction may be done carefully. In this project a dynamic modeling of risers is proposed, with the usage of nonlinear beam models, with no theoretical magnitude limitation for displacements and rotations, and also a treatment of the nonlinear contact condition between the riser and the seabed using the Mortar Method, with the usage of Lagrange multipliers. Specifically for the contact interaction, the structure will be described using splines or the Moving Least Squares Method. The development of this new contact modeling technique will lead to interesting results of riser-seabed dynamic interaction. Furthermore, the model may be used for studies of practical dynamic problems, such as the risers' instability with a dynamic focus, loop formation scenarios and for predicting the curvature radiuses in post-buckling configurations, in dynamic compression situations of riser region close to the touchdown point.

Scientific publications

(7)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

NETO, ALFREDO GAY; MARTINS, CLOVIS DE ARRUDA. Flexible Pipes: Influence of the Pressure Armor in the Wet Collapse Resistance. JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING-TRANSACTIONS OF THE ASME, v. 136, n. 3, AUG 2014. (12/09912-0)

GAY NETO, ALFREDO; MARTINS, CLOVIS DE ARRUDA. Structural stability of flexible lines in catenary configuration under torsion. MARINE STRUCTURES, v. 34, p. 16-40, DEC 2013. (12/09912-0, 06/06277-0, 12/21167-8)

FRANZINI, GUILHERME ROSA; NETO, ALFREDO GAY; CROCKER, MJ; PAWELCZYK, M; PEDRIELLI, F; CARLETTI, E; LUZZI, S. NUMERICAL INVESTIGATIONS ON PARAMETRIC EXCITATION OF A VERTICAL BEAM UNDER PRESCRIBED AXIAL DISPLACEMENTS. PROCEEDINGS OF THE 22ND INTERNATIONAL CONGRESS ON SOUND AND VIBRATION, v. N/A, p. 8-pg., 2015-01-01. (12/09912-0)

GAY NETO, ALFREDO; PIMENTA, PAULO M.; WRIGGERS, PETER. Self-contact modeling on beams experiencing loop formation. COMPUTATIONAL MECHANICS, v. 55, n. 1, p. 193-208, JAN 2015. (12/09912-0, 14/11910-0)

GAY NETO, ALFREDO; MARTINS, CLOVIS A.; PIMENTA, PAULO M.. Static analysis of offshore risers with a geometrically-exact 3D beam model subjected to unilateral contact. COMPUTATIONAL MECHANICS, v. 53, n. 1, p. 125-145, JAN 2014. (12/09912-0, 06/06277-0, 12/21167-8)

GAY NETO, ALFREDO; PIMENTA, PAULO M.; WRIGGERS, PETER. Contact between rolling beams and flat surfaces. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, v. 97, n. 9, p. 683-706, MAR 2 2014. (12/09912-0, 12/21167-8)

NETO, ALFREDO GAY; MALTA, EDUARDO RIBEIRO; PIMENTA, PAULO DE MATTOS. Catenary riser sliding and rolling on seabed during induced lateral movement. MARINE STRUCTURES, v. 41, p. 223-243, APR 2015. (12/09912-0)