Oil and gas exploration and production activities in deep and ultra deep waters in hostile environments necessitates the need to develop innovative riser systems capable of ensuring transfer of fluids from the seabed to a floating vessel and vice versa, with little or no issues with respect to influences of environmental loads and vessel motions.The design of the riser system must focus on different types of loading and load effects than for traditional water-depth. A variety of different riser concepts are proposed, both with respect to geometric shape and selection of materials.In the last few years, steel catenary risers have been a preferred riser solution for deep-water field developments due to its simple engineering concept, cost effective, flexibility in using different host platform and flexibility in geographical and environmental conditions. In this report, a case study considering a steel catenary riser operating in 1000 m water depth was conducted. The riser was subjected to extreme environmental conditions and static and dynamic response analyses were performed by the computer program RIFLEX.Last, parametric study is carried out to investigate the effects of parameter variation based on some parameters like current profiles, mesh density, wall thickness and so on. These parameters have significant effect on the structural response, especially in the touch down region.

Due to the substantial increase in oil and gas activities in Polar areas the demand for ice strengthen vessel has increased greatly. This increase in demand has highlighted the importance of designing ice strengthened ship structures that are more producible and maintain adequate safety and integrity. In order to encounter these new challenges, the international association of classification societies (IACS) has developed unified regulations for the designing of ice strengthened ship. In addition to these requirements, most of the classification societies have their regulation for design of polar ships. Stiffened plates are the basic structural building blocks of ships. So, the study mainly explores the plastic response of stiffened plate subject to lateral ice loads. The Non Linear Finite Element Method (NLFEM) is extensively used to study the plastic behavior of stiffened plates. The Abaqus non linear finite element program is used in this study.The aims of the study are to investigate the validity of the limit state equation employed in the IACS new Unified Requirements for Polar Ships [6], investigate the membrane effect at large deformation, determine the ALS design load, and assess limit loads when fracture in plating likely to take place. The study also focuses on the warping effect of unsymmetrical sections and the effect of end brackets on the lateral load carrying capacity of the stiffener. The effect of mid-span tripping bracket on the load deflection behavior of L and T stiffeners is also studied. In particular, the study focuses on the behavior of inclined T and L stiffener. As ships move forward by crushing ice, sides of ships’ bow come across with ice initially. To design ice strengthen vessel, it’s very important to understand the behavior of ships’ side structure subjected to ice loads. So, this study extensively focuses on the non-linear finite element analysis of ships’ side structure subjected to ice loads. Normally, ship design rules are based on the behavior of single frame subjected to loads. It’s reasonable to consider frames singly under the uniform loading but in case of ice loading which is non uniform, the behavior of the structure obtained from single frame based design does not accurately represent the true behavior of the structure. The load-deflection characteristic of frames in isolation, frames as part of a ½+1+½ frames and frames as part of a grillage subjected to unsymmetrical loading is studied. As, stiffeners in the side structure of ships’ bow are not normally perpendicular with shell plate, the lateral capacity of frames as part of a ½+1+½ frames and as part of a grillage is obtained for inclined stiffener.The analyses in this study cover the full range of stiffener behavior from elastic, through yield, through the formation of initial mechanisms, through large deformations. The parameters considered for the analyses are: •frame profile: Angle, Tee•frame span•load length: patch (transverse), uniform (longitudinal)•web thickness•end brackets: with, without•Angle of inclination of stiffener web with the plate flange•Tripping bracket at mid span

Fatigue is an important character for the flexible pipes as they are always exposed to dynamic loading. For nonbonded flexible pipes, fatigue and stress analysis can be performed based on different assumptions of slip behaviour. Different slip assumptions used in estimating the slip stress always play a determinative role in the prediction of fatigue damage. Thus, this thesis will focus on the study of the slip behaviour between tensile armour layers of nonbonded flexible pipes. The results can be used to support the basic assumptions for further fatigue analysis. The main object of this thesis is to summarize the existing analytical methods for stress and slip analysis of nonbonded flexible pipe armouring layers and to verify that the improved finite element models can give adequate description of the flexible pipe slip behaviour.In previous version of BFLEX, the transverse slip effect for nonbonded flexible pipes has been neglected. In this thesis, transverse slip regime has been activated in the updated BFLEX by developing a new type of beam element hshear353 and a new type of contact element hcont453. Finite element models use these two elements have been made and several case studies have been carried out.For axisymmetric loading, two analytical solutions, one obtained from the equations by Witz&Tan[13], one from Sævik[2] have been compared with the result from numerical simulation. It has been found that Sævik’s solution matches better with the BFLEX solution comparing to Witz&Tan’s solution. For flexible pipes exposed to bending, influences on slip behaviour from several pipe parameters, namely friction coefficient, axial strain and global pipe curvature, have been investigated. The numerical results are also compared with analytical solutions obtained from Sævik[2]. It has been found that the numerical solutions can give excellent agreement with analytical solutions. It is further concluded that the outer tensile armour layer do not influence much on the inner layer slip behaviour.In addition, the cyclic bending effects on nonbonded flexible pipes have been investigated. It has been found that the tendon behaves differently from case to case. The inner and outer layers behave differently. Only a few cases have been studied for this problem due to time limitation. The overall conclusion is that the developed BFLEX model is capable of describing the stresses and local displacements of flexible pipe for simple cases. The developed numerical model can further be used in the study of fatigue in flexible risers. However, more studies on influence from multi-tensile layers and cyclic bending are needed in the future.

Platform-ship collisions are fortunately rare events, but as the development of the offshore and oil industry and the gradually frequently used offloading operation, accidents become more and more frequent. The consequences of collisions are always severe, which includes loss of life, property and environmental damage. Thus It is important to predict the outcome of collision scenarios and assess the damage that may happen to the platform as well as the shuttle tanker.Collisions are always analyzed by means of the principle of the principle of energy conservation. Initial kinetic energy is dissipated by the two contact bodies as strain energy and in viscous force generation. There is also energy remained as the kinetic energy after the impact for both the striking and struck bodies, both for translational and rotational degrees of freedom. The external mechanics of the collision is easily evaluated, but the strain energy absorption can be rather difficult to evaluate in a correct way.In this thesis, A Samsung shuttle tanker and the Sevan SSP300 platform are analyzed as the striking and struck bodies, respectively. Structural configurations are described for both structures. Different impact scenarios are then discussed in the report, some of which are chosen to analyze in the thesis work. Non Linear Finite Element Analysis (NLFEA) model of the SSP300 platform is created. The shuttle tanker model is an exist one. One-sixth of the platform is modeled in detail with the correct stiffeners and other details, while for the other part, only the outer shell and the main bulkheads are modeled. For the tanker, adjustments are made in order to increase the calculation efficiency. Only the bow is remained in details. For the hull, only the outer shell is remained. For both structural models, adjustments are made to obtain the correct mass, added mass and inertial. Both models have a user defined material with the fracture criterion included. Integrated analysis is mainly performed. Then the integrated analysis is split into internal mechanics and external mechanics. Among these, integrated analysis and internal mechanics analysis are performed with finite element method, using the explicit NLFEA solver LS-DYNA. For the collision scenarios, only bow impact with different headings is considered. Two different impact velocities are chosen in both head on collision and collision with the glancing angle of 30 degrees. Energy absorption and force-displacement relationship can be obtained. Damage on the platform is also evaluated. Internal mechanics are then analyzed by changing the boundary condition and making the impact velocity constant. The purpose is to evaluate the damage with internal mechanics and then compare it with the results from integrated analysis. Liu’s method, which is based on Stronge theory, is mainly used in external mechanics as a simplified method. Herein a Matlab program is established to calculate the energy dissipation and the velocity after the impact. Two other simplified methods are utilized to calculate the dissipated energy and then compare them with the results from NLFEA analysis. One is from the DNV-RP-C204 and the other one is from T.de Jonge&L.laukeland’s report. The latter one is an optimized method compared to the one from DNV rules, which includes the effect of roll motion. Results from the simplified methods and NLFEA method show good correlation. All the simplified methods overestimate the absorbed energy, which is conservative. Among these, Liu’s method gives the best correlation with the NLFEA method. Two additional jobs are conducted in the end. Only the energy dissipation is analyzed in this section. One is changing the loading conditions of the two bodies. The energy dissipation becomes smaller after changing. The other one is changing the friction coefficient. The energy dissipated by the tanker is smaller, while by the platform is larger. But from the overall view, the energy does not show big difference with friction coefficient 0.15 and 0.4.

The construction of coastal ports requires the use of materials that meet the demands of the marine environment, to prevent underwater concrete structures from cracking and spalling easily; basalt fiber is used to delay the expansion of concrete and prevent the formation of cracks. This research studies the behavior of concrete for prefabricated piles with Portland Cement Type I and basalt fibers added in 0.1%, 0.3% and 0.6%; the results indicate that the fiber is suitable for concrete, the slump decreases, the compressive strength increases for specimens cured in tap water and sea water, the relationship between resistances does not vary, and the depth of carbonation decreases.

Orientador: Celso Kazuyuki Morooka / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-21T15:20:32Z (GMT). No. of bitstreams: 1 Suzuki_MauricioJun-DiHiroyama_M.pdf: 1999109 bytes, checksum: d41245aad316f0ae861128e4b001c40c (MD5) Previous issue date: 2012 / Resumo: Risers de produção são elementos tubulares que conectam a cabeça de um poço no fundo do mar a uma plataforma de petróleo, escoando a produção de óleo e gás. Para o estudo de uma sistemática para análise de operação e projeto de risers, faz-se muito importante o entendimento da modelagem matemática para previsão de seu comportamento estático e dinâmico e avaliação de sua vida útil. O objetivo dessa previsão é buscar uma melhor configuração para sua operação e projeto em função, principalmente, da profundidade de operação e das condições ambientais. Procedimentos numéricos têm sido desenvolvidos para determinar comportamento de um riser. Forças hidrodinâmicas, devido aos carregamentos ambientais, tais como esforços de ondas e correntezas marítimas, influenciam o comportamento de risers, e ainda, quando são conectados a plataformas flutuantes de produção, estas, estando também sujeitas à ação de ondas e correntezas, apresentam movimentos que se transferem aos risers. Essas excitações de diferentes origens geram esforços e tensões na estrutura dos risers. Outro fenômeno importante é oriundo dos esforços oscilatórios devido ao escoamento interno. O presente trabalho tem como objetivo investigar a influência dos parâmetros do solo na resposta dinâmica de risers em catenária sob a ação do meio ambiente e movimentos de plataformas flutuantes / Abstract: Production risers are tubular elements that connect the head of an undersea well to the floating petroleum production facility. They transport oil, water and gas. For the study of a systematic approach to the analysis of the operation and the design of risers, the agreement of the mathematical models that predict the static and dynamic behavior and the evaluation of its service life are important. The objective of these models is to search for the best configuration for the operation and design of the riser. A critical concern is the complexity of operation and the environmental conditions. Numerical procedures have been implemented to determine the behavior of the riser. Hydrodynamic forces such as induced by waves and ocean currents influence the behavior of risers. Moreover, the risers are connected the floating platforms which also exerts further forces on the riser. These platforms also are affected by the waves and current, which produce motion that is then transferred to the risers generating stresses and tensions in the riser's structure. Another very important phenomenon is the oscillatory stresses due to variations in the two-phase internal flow. The objective of this work is evaluated the influence of the soil parameters on the dynamic behavior of catenary risers in ultra-deep waters application / Mestrado / Explotação / Mestre em Ciências e Engenharia de Petróleo

Orientador: José Mario De Martino / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-23T00:16:40Z (GMT). No. of bitstreams: 1 Ramos_RafaelGuimaraes_M.pdf: 8228877 bytes, checksum: 7b943d579b89dd9cb856e7bc292a1c33 (MD5) Previous issue date: 2013 / Resumo: Este trabalho apresenta um ambiente de visualização interativo em tempo-real para a simulação do comportamento de risers rígidos verticais. O riser é um duto cilíndrico essencial na extração de óleo em águas profundas e ultra-profundas, uma tarefa desafiadora que impõe diversas cargas sobre a estrutura. Ondas, correntes e movimentos da plataforma são algumas dessas fontes de tensão, que podem levar a danos por fadiga ou mesmo rupturas. Simulações computacionais é uma ferramenta de grande valia para prevenir e diagnosticar tais problemas, mas em geral apresentam a desvantagem de produzir um grande volume de dados numéricos de difícil interpretação. Técnicas de visualização científica podem ser utilizadas para representar os dados de uma maneira mais intuitiva e realista. Entretanto, os sistemas identificados na literatura apresentam limitações quanto à interação em tempo-real. A visualização é realizada como um playback, após a simulação ter sido completado, e sempre que os parâmetros de simulação são alterados o usuário deve esperar um tempo considerável enquanto os resultados são recalculados. Neste trabalho, o ambiente desenvolvido permite a visualização do comportamento do riser com interação em tempo-real, em que o novo comportamento do riser é obtido imediatamente após os parâmetros de simulação ser alterado pelo usuário / Abstract: This work presents a visualization environment with real-time interaction for the simulation of vertical rigid risers. The riser is a cylindrical pipe essential for the extraction of oil in deep and ultra-deep waters, a challenging task that imposes several loads over the structure. Waves, currents and platform movements are some of these stress sources that may lead to fatigue damage or even rupture. Computer simulations are a tool of great value for preventing and diagnosing such problems, but have usually the drawback of producing a large volume of numerical data difficult of being interpreted by the user. Scientific visualization techniques can be used to represent data in a more intuitive and realistic way. However, projects identified in the literature present limitations regarding real-time interaction. The visualization is performed as a playback, after the simulation has been completed, and whenever simulation parameters are changed, the user has to wait a considerable time for the results to be recalculated. In this work, the developed simulation environment allows visualization of riser behavior with real-time interaction, where the new riser behavior is obtained immediately after simulation parameters are changed by the user / Mestrado / Engenharia de Computação / Mestre em Engenharia Elétrica

This thesis presents the development and testing of distributed vibration absorber designs with specific application to heavy plates for the reduction of vibration and sound radiation. Two particular designs, already under investigation for use on thin panels or composite materials, were adapted to passively reduce broadband vibration and noise from large and heavy plates. These absorbers are referred to as Distributed Vibration Absorbers [DVAs] and Heterogeneous [HG] Blankets. Numerical models were developed, based on the theory of sound propagation through layered media and the vibration of plates, to simulate the performance of such absorbers for a variety of applications and media characteristics. The new absorber designs were then tested on a large, marine-type plate (4 feet by 2 feet by 1/4 inch) and showed both broadband noise and vibration control from 60 Hz to 5 kHz. DVAs could reduce the vibrating plate resonance magnitudes on the order of 15 dB at their tuning frequencies while providing overall vibration reduction of 5 dB or greater at higher frequencies. HG blankets were also capable of reducing plate resonance vibration up to 15 dB at their tuning frequencies and produced overall vibration reduction of 5 dB at higher frequencies. These absorbers are entirely passive, i.e. requiring no controller or prior modal testing of the structure, were placed randomly during testing, and are designed to contribute less than 10% additional mass to the structure, making them a robust vibration and noise control solution. / Master of Science

Orientador: Renato Pavanello / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-14T01:23:32Z (GMT). No. of bitstreams: 1 Morini_RafaelGiovane_M.pdf: 17374266 bytes, checksum: e5f034607ded57361d157d72f2fb7810 (MD5) Previous issue date: 2009 / Resumo: A dissertação é dedicada ao estudo do comportamento estrutural estático de risers rígidos montados em catenária para aplicações na exploração de petróleo em águas profundas. Estuda-se o problema de equilíbrio estático de risers, no qual é considerado o efeito do peso próprio, do empuxo, e a interação com o solo. Para tanto, utiliza-se do Método de Elementos Finitos Posicional, que é baseado em posições dos nós ao invés de deslocamento nodal, sendo que o referencial utilizado é o Lagrangiano Total. Adota-se a cinemática de Reissner para descrever o comportamento do pórtico plano, na qual são consideradas as deformaçõoes oriundas das tensões de cisalhamento. Utiliza-se o algoritmo de Newton-Raphson para a solução iterativa do problema não linear e o método de penalidades para a solução do problema de contato com o solo. São desenvolvidos estudos comparativos e de sensibilidade de alguns parametros envolvidos no problema de risers com o objetivo de avaliar a influencia do modelo do solo, das condições do contato solo-riser na região de toque sobre o comportamento estático do sistema acoplado. Os resultados são validados com resultados da literatura e por comparação de resultados obtidos com o programa Anflex, atualmente utilizado pela Petrobras. / Abstract: This dissertation is dedicated to the study of static structural behavior of Steel Catenary Riser for applications in oil exploitation in deep waters, considering soil-riser interaction. In this way, the problem of equilibrium static of risers, which is related to the self weight effect, thrust effect and the interaction with the soil is studied. For this purpose, the Positional Finite Element Method was used, which is based on positions of nodes instead of nodal displacements. The Total Lagrangian description was used. The beam's behavior was described with the Reissner kinematics. Newton-Raphson algorithm for iterative solution of nonlinear problem and the method of penalties for the solution to the problem of contact with the ground were used. The influence of soil model and soil-riser interaction conditions on the touch down point are evaluated by comparative studies of sensitivity of some parameters involved in the riser's problem. The results are validated with those from literature as well as they were compared with those provided by the software Anflex, which is currently used by Petrobras company. / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Orientador: Renato Pavanello / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-18T13:26:34Z (GMT). No. of bitstreams: 1 Antonio_LeonardoMachado_M.pdf: 4297559 bytes, checksum: 9607067525a5f1e234ed72d8bcef64ef (MD5) Previous issue date: 2011 / Resumo: A explotação de petróleo em ambientes off-shore possui inúmeras dificuldades, dentre as quais lâminas d'águas cada vez mais profundas. Neste contexto, as linhas submarinas são componentes de grande importância nesta atividade, pois estabelecem a comunicação entre as unidades de produção e os equipamentos submarinos. Este trabalho estuda a interação solo-estrutura de risers rígidos em catenária utilizando a formulação co-rotacional através de abordagens estática e dinâmica. A abordagem estática trata do equílibrio estático de estruturas não-lineares, no qual utiliza-se a estratégia de controle por carregamento;enquanto a abordagem dinâmica utiliza a discretização temporal de Newmark para resolução do equílibrio dinâmico de estruturas não-lineares. Este estudo mostra a implementação de modelos com um e dois parâmetros baseados das hipóteses de Winkler, Filonenko-Borodich e Pasternak no contexto interação da estrutura do riser com o leito marinho / Abstract: The petroleum explotation on off-shore enviorments has differents dificulties, for example deeper water deths. In this context, the marine pipes are components of extreme importance, since they are the comunication between the production units and the subsea equipaments. This work studies the soil-structure interaction of steel cathenary risers using corotational formulation within static and dynamic approaches of structural calculation. The static approach focus on the non-linear static equilibrium of structures using the load control strategy. On the other side, the dynamic approach uses the Newmark time discretization to solve the non-linear dynamic equilibrium equation. This study shows the implementation of foundation with one and two parameter based on hipotheses of Winkler, Filonenko-Borodich and Pasternak in the riser structure and soil interaction context / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica