Modeling and parameter estimation in flexible riserbend stiffener top connection

• Ano de defesa: 2019
• Autor(a) principal: He, Yangye
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal do Rio de Janeiro; Brasil; Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia; Programa de Pós-Graduação em Engenharia Oceânica; UFRJ
• Palavras-chave em Português: Conexão de topo de riser; Enrijecedor à flexão; Distribuição de curvatura; Estimativa de parâmetros; Teste de flexão; Medições baseadas em imagem; CNPQ::ENGENHARIAS::ENGENHARIA NAVAL E OCEANICA
• Link de acesso: http://hdl.handle.net/11422/13570

The flexible riser top connection is a critical region for fatigue lifetime (re)assessment due to large tension/curvature variation and modeling uncertainties. Both the bend stiffener effect on the curvature distribution and top tension time series could be its inherent uncertainties. In this work, a large deflection beam bending model is developed to represent the flexible riser-bend stiffener top connection with I-tube interface, considering the nonlinear bending behaviors of riser and bend stiffener subjected to a top tension with a rotated angle. The corresponding mathematical formulation with multipoint boundary conditions is numerically solved by an iterative procedure in Mathematica. Large deflection response of the top connection and parametric assessments of I-tube length and sleeve curved radius are analyzed in a case study, including the end-fitting curvature and contact forces of riser with bend stiffener and sleeve. A proposed monitoring approach composed by gyrometers installed along the riser/bend stiffener length combined with the Levenberg-Marquardt (L-M) algorithm, is investigated in riser/bend stiffener system to numerically estimate the unknown top tension and polyurethane elastic response. A preliminary feasibility investigation is implemented in a case study with the gyrometer data numerically generated by Monte Carlo simulations. The sensor number and arrangement, loading conditions and direct top connection model may significantly influence the estimations. Furthermore, a full-scale bendingtension test of riser/bend stiffener with the image-based measurements is presented with unknown material response.