Eventos Anais de eventos
DINAME 2023
XIX International Symposium on Dynamic Problems of Mechanics
Nonlinear normal modes of flexible risers in catenary configuration
Submission Author:
Gustavo Brattstroem Wagner , RJ
Co-Authors:
Gustavo Brattstroem Wagner, Roberta Lima, Rubens Sampaio
Presenter: Rubens Sampaio
doi://10.26678/ABCM.DINAME2023.DIN2023-0020
Abstract
Risers are offshore pipelines that connect a floating vessel to the bottom of the ocean, allowing oil to be extracted. Because the oil exploration is already being held at extreme deep levels, some of the risers are being design as flexible structures. Flexible beams are usually modeled under the assumption of large displacements and large rotations of the cross sections, but with small strains. Such hypotheses lead to a geometric nonlinearity that can be efficiently incorporated to the model using co-rotational finite element. Instead of performing numerical integration of the equation of motion to analyze the dynamics of flexible beams, this paper proposes a procedure to compute the nonlinear normal modes of this structure. The Rosenberg's definition is used, which allows the nonlinear normal modes to be computed using the Harmonic Balance Method and a numerical continuation scheme. The procedure is validated for a flexible riser in catenary configuration.
Keywords
Harmonic Balance, Flexible beams, Co-rotational finite elements, Continuation methods, nonlinear normal modes
