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Clovis De Arruda Martins - One of the best experts on this subject based on the ideXlab platform.
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flexible pipes influence of the Pressure Armor in the wet collapse resistance
Journal of Offshore Mechanics and Arctic Engineering-transactions of The Asme, 2014Co-Authors: Clovis De Arruda MartinsAbstract:When submitted to high external Pressure, flexible pipes may collapse. If the external sheath is damaged, all the external Pressure is directly applied on the internal polymeric layer that transmits the loading to the carcass layer, which can fail due to this effect, leading to wet collapse. This failure mode must be taken into account in a flexible pipe design. A model can be set up neglecting the influence of the Pressure Armor, but this assumption may underestimate the wet collapse Pressure value. This work aims to include the Pressure Armor effect in the numerical prediction of wet collapse. The main contribution of the Pressure Armor to the flexible pipe resistance to collapse is to be a constraint to the radial displacement of the carcass and the internal polymeric layers. Two models were developed to find the wet collapse Pressure in flexible pipes. A first study was done using a ring approximation three-dimensional (3D) finite element method (FEM) model. Comparisons are made with more simplified models using a 3D FEM equivalent ring approximation. The aim is to clarify the mechanical behavior of the Pressure Armor in the wet collapse scenario. Parametric studies of initial ovalization of carcass and initial gaps and interference between polymeric layer and Pressure Armor are made and discussed.
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flexible pipes influence of the Pressure Armor in the wet collapse resistance
ASME 2011 30th International Conference on Ocean Offshore and Arctic Engineering, 2011Co-Authors: Clovis De Arruda MartinsAbstract:When subjected to large valued external Pressures, flexible pipes may collapse. If the external sheath is damaged, all the external Pressure is directly applied to the internal polymeric layer that transmits the loading to the carcass layer. When the carcass layer fails due to this effect, the wet collapse occurs. This failure mode must be taken into account in the flexible pipe design. The study for this problem can be done neglecting the influence of the Pressure Armor, but this assumption may underestimate the wet collapse Pressure value. This work aims to study the Pressure Armor effect in the numerical prediction of wet collapse. The main contribution of the Pressure Armor to the flexible pipe resistance to collapse is to be a constraint to the radial displacement of the carcass and the internal polymeric layers. Two models were developed and compared with the purpose of calculating the critical value of the external Pressure that causes carcass layer to collapse. The first and most complete study is done using a ring 3D FEM model that takes into account both the real Pressure Armor and carcass real profiles. In the second model, the Pressure Armor is considered adopting an equivalent ring simplification. The comparison of the results of both the models clarifies how the behavior of the Pressure Armor in the wet collapse situation is. Parametric studies of initial ovalization of the carcass and initial gaps in manufacturing of flexible pipes are made and discussed.Copyright © 2011 by ASME
Herrera Paulo - One of the best experts on this subject based on the ideXlab platform.
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Study of wear resistance of the flexible riser zeta Pressure Armor submitted to deep cryogenic treatment and plasma nitriding
2016Co-Authors: Herrera PauloAbstract:Risers são estruturas multicamada compostas por arames metálicos e camadas poliméricas, utilizados no transporte e produção de petróleo. A armadura de pressão é a camada responsável por suportar as cargas radiais de pressões internas do riser, sendo produzida a partir de um arame helicoidal de aço e que possui intertravamento. Devido a parâmetros de projeto, existe a necessidade de o aço utilizado possuir uma certa ductilidade. O intertravamento que confere flexibilidade ao riser é responsável pelo desgaste na armadura de pressão, uma vez que o atrito e o movimento relativo nesta pode ocasionar a aparição de partículas, caracterizando assim um desgaste microabrasivo. O presente trabalho visa estudar o efeito do tratamento criogênico profundo e da nitretação a plasma no desgaste microabrasivo da região de contato da armadura de pressão. Para tanto, foram retiradas amostras diretamente da região de contato de uma armadura de pressão e realizado ensaios de caracterização do material e ensaio de desgaste microabrasivo por esfera rotativa livre. As amostras foram testadas como recebidas, com o tratamento criogênico profundo e com nitretação a plasma realizada a 515 °C por 8, 24 e 48 horas de duração. O material com tratamento criogênico profundo apresentou um perfil de microdureza Vickers e um coeficiente de desgaste muito semelhante ao da amostra como recebida. As amostras nitretadas apresentaram um valor de microdureza próximo à região superficial maior que ao da amostra como recebida (21,8%, 23,2% e 29%), além de apresentar também uma melhora no coeficiente de desgaste na região transiente (29,85%, 28,53% e 29,81%) e permanente (19,18%, 25,19% e 28,09%). _________________________________________________________________________________________________ ABSTRACTRisers are multilayer structures composed of metallic wires and polymeric layers, used in oil production and transportation. The Pressure Armor is the layer responsible for supporting the internal radial Pressures and is produced from a helical interlocked steel wire. Due to project parameters, the steel used possesses a certain ductility. The interlocking structure which gives flexibility to the riser is also responsible for wear on the Pressure Armor, with friction and relative motion causing the appearance of particles, resulting in a micro-abrasive wear. The present work aims to study the effect of deep cryogenic treatment and plasma nitriding on the micro-abrasive wear of the contact patch of the Pressure Armor. Samples were taken directly from the contact region of the Pressure Armor. Material characterization and the micro-abrasive wear test were performed on a free ball machine. The tests were conducted on the samples as received, with deep cryogenic treatment and with plasma nitriding (at 515 °C for 8, 24 and 48 hours). It was observed that the material with deep cryogenic treatment had a Vickers microhardness profile and wear coefficient very similar to that of the sample without treatment. The nitrided samples showed a higher (21.8%, 23.2% and 29%) microhardness value at the surface region than the sample as received, and also an improvement in wear coefficient in the transient region (29.85%, 28.53% and 29.81%) and permanent region (19,18%, 25,19% and 28,09%)
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Study of wear resistance of the flexible riser zeta Pressure Armor submitted to deep cryogenic treatment and plasma nitriding
'Biblioteca Central da UNB', 2015Co-Authors: Herrera PauloAbstract:Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2015.Risers são estruturas multicamada compostas por arames metálicos e camadas poliméricas, utilizados no transporte e produção de petróleo. A armadura de pressão é a camada responsável por suportar as cargas radiais de pressões internas do riser, sendo produzida a partir de um arame helicoidal de aço e que possui intertravamento. Devido a parâmetros de projeto, existe a necessidade de o aço utilizado possuir uma certa ductilidade. O intertravamento que confere flexibilidade ao riser é responsável pelo desgaste na armadura de pressão, uma vez que o atrito e o movimento relativo nesta pode ocasionar a aparição de partículas, caracterizando assim um desgaste microabrasivo. O presente trabalho visa estudar o efeito do tratamento criogênico profundo e da nitretação a plasma no desgaste microabrasivo da região de contato da armadura de pressão. Para tanto, foram retiradas amostras diretamente da região de contato de uma armadura de pressão e realizado ensaios de caracterização do material e ensaio de desgaste microabrasivo por esfera rotativa livre. As amostras foram testadas como recebidas, com o tratamento criogênico profundo e com nitretação a plasma realizada a 515 °C por 8, 24 e 48 horas de duração. O material com tratamento criogênico profundo apresentou um perfil de microdureza Vickers e um coeficiente de desgaste muito semelhante ao da amostra como recebida. As amostras nitretadas apresentaram um valor de microdureza próximo à região superficial maior que ao da amostra como recebida (21,8%, 23,2% e 29%), além de apresentar também uma melhora no coeficiente de desgaste na região transiente (29,85%, 28,53% e 29,81%) e permanente (19,18%, 25,19% e 28,09%).Risers are multilayer structures composed of metallic wires and polymeric layers, used in oil production and transportation. The Pressure Armor is the layer responsible for supporting the internal radial Pressures and is produced from a helical interlocked steel wire. Due to project parameters, the steel used possesses a certain ductility. The interlocking structure which gives flexibility to the riser is also responsible for wear on the Pressure Armor, with friction and relative motion causing the appearance of particles, resulting in a micro-abrasive wear. The present work aims to study the effect of deep cryogenic treatment and plasma nitriding on the micro-abrasive wear of the contact patch of the Pressure Armor. Samples were taken directly from the contact region of the Pressure Armor. Material characterization and the micro-abrasive wear test were performed on a free ball machine. The tests were conducted on the samples as received, with deep cryogenic treatment and with plasma nitriding (at 515 °C for 8, 24 and 48 hours). It was observed that the material with deep cryogenic treatment had a Vickers microhardness profile and wear coefficient very similar to that of the sample without treatment. The nitrided samples showed a higher (21.8%, 23.2% and 29%) microhardness value at the surface region than the sample as received, and also an improvement in wear coefficient in the transient region (29.85%, 28.53% and 29.81%) and permanent region (19,18%, 25,19% and 28,09%)
P. V. Muterlle - One of the best experts on this subject based on the ideXlab platform.
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Wear resistance of the Pressure Armor submitted to deep cryogenic treatment and plasma nitriding
Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2018Co-Authors: P. Herrera, P. V. MuterlleAbstract:Risers are multilayer structures used in oil production and transportation. The Pressure Armor is the layer responsible for supporting the internal radial Pressure and is produced from a helical interlocked steel wire. The interlocking mechanism, which gives flexibility to the riser, is responsible for the wear on the Pressure Armor, resulting in a micro-abrasive wear. The present work aims to study the effect of deep cryogenic treatment and plasma nitriding on the micro-abrasive wear in the Pressure Armor. Samples tested were taken from the contact region of the Pressure Armor. The micro-abrasive wear test was performed on a free ball machine. The tests were conducted on the samples as received, with deep cryogenic treatment and with plasma nitriding (at 515 °C for 8, 24 and 48 h). It was observed that the material with deep cryogenic treatment had a Vickers microhardness profile and wear coefficient similar to the sample as received. The nitrided samples showed a higher (21.8%, 23.2% and 29%) microhardness value at the surface region than the sample as received and an improvement in wear coefficient in the transient (29.85%, 28.53% and 29.81%) and permanent (19.18%, 25.19% and 28.09%) regions.
P. Herrera - One of the best experts on this subject based on the ideXlab platform.
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Wear resistance of the Pressure Armor submitted to deep cryogenic treatment and plasma nitriding
Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2018Co-Authors: P. Herrera, P. V. MuterlleAbstract:Risers are multilayer structures used in oil production and transportation. The Pressure Armor is the layer responsible for supporting the internal radial Pressure and is produced from a helical interlocked steel wire. The interlocking mechanism, which gives flexibility to the riser, is responsible for the wear on the Pressure Armor, resulting in a micro-abrasive wear. The present work aims to study the effect of deep cryogenic treatment and plasma nitriding on the micro-abrasive wear in the Pressure Armor. Samples tested were taken from the contact region of the Pressure Armor. The micro-abrasive wear test was performed on a free ball machine. The tests were conducted on the samples as received, with deep cryogenic treatment and with plasma nitriding (at 515 °C for 8, 24 and 48 h). It was observed that the material with deep cryogenic treatment had a Vickers microhardness profile and wear coefficient similar to the sample as received. The nitrided samples showed a higher (21.8%, 23.2% and 29%) microhardness value at the surface region than the sample as received and an improvement in wear coefficient in the transient (29.85%, 28.53% and 29.81%) and permanent (19.18%, 25.19% and 28.09%) regions.
J S Ju - One of the best experts on this subject based on the ideXlab platform.
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on the response and prediction of multi layered flexible riser under combined load conditions
Engineering Computations, 2019Co-Authors: Jian Li, Lixin Chen, J S JuAbstract:The internal force is more complicated in a combined load case than in a single load case, and the influence of the combined load on the stress cannot be neglected. The purpose of this paper is to study the mechanical behavior of the flexible riser under combined load conditions of tension and internal Pressure or external Pressure.,The mechanical behavior of the flexible riser under combined load conditions is studied by numerical simulation with a nine-layer detailed finite element model. The layers of flexible riser are modeled separately, and the interactions between layers have been taken into consideration in numerical simulation.,Under tension and internal Pressure or external Pressure, the Pressure Armor will bear extra external Pressure because of the squeezing actions between layers caused by tension, and the extra external Pressure will increase proportionately with the increase of the tension. Under internal Pressure and tension, the internal stress for tension Armor was nearly unchanged compared to that under unique tension load, whereas under external Pressure and tension, the change of internal stress for tension Armor was significant. Prediction methods of internal force for Pressure Armor and tension Armor under Pressure and tension are given, and the result from the formula agrees well with the simulation results.,The prediction methods on the internal force of flexible riser proposed in this study are proven accurate, with numerical simulation results, and the prediction methods are convenient for engineering applications.