TEDE Communidade:
http://www.bdtd.uerj.br/handle/1/3679
2024-03-28T22:42:25ZEstudo do comportamento estrutural estático e dinâmico de tanques de aço para armazenamento de líquidos
http://www.bdtd.uerj.br/handle/1/21523
Título: Estudo do comportamento estrutural estático e dinâmico de tanques de aço para armazenamento de líquidos
Autor: Lopes, Matheus Abreu
Primeiro orientador: Silva, José Guilherme Santos da
Abstract: The scenario of increasing oil production in the Brazilian oil and gas industry has been demanding more efficiency in the operation and maintenance of logistic assets, such as cylindrical steel tanks used for the storage of oil and its derivatives. On the other hand, these equipment experience damage throughout their lifespan, such as structural deformations due to their high slenderness ratio, because of their very low thickness-to-diameter ratios. In this context, it is necessary to assess the integrity of these equipment in the presence of these structural damages to ensure a safe operational continuity. The consideration of imperfections in the calculation models must be as realistic as possible to obtain a precise assessment of the structure in the presence of defects. However, methods for the dimensional inspection of large structures like storage tanks often involve topographical surveys at specific points on the structure, which may not be very suitable for accurately quantifying imperfections. Therefore, the use of 3D laser scanning inspection tools can be an excellent ally. Regarding failure modes, tanks are susceptible to wind-induced buckling, especially in the presence of structural imperfections. Wind, which is a phenomenon with unstable and random behavior, is typically considered as a static load with a deterministic formulation. However, this consideration may not reveal certain behaviors, such as the dynamic buckling of tanks. Therefore, considering the dynamic and non-deterministic effects of wind is recommended to capture these events. In addition, other failure modes such as plastic collapse and excessive localized plastic strains can compromise structural integrity and should be investigated through calculation models that allow for the assessment of the structure in its current state, with a precise representation of its geometry. Thus, this work aims to develop a methodology for the structural analysis of operating storage tanks containing imperfections (deformations) in their structure. The methodology involves the precise dimensional survey of the structure using 3D laser scanning, with the results used to calibrate a finite element model. The developed model is employed in static analyses focused on evaluating failure due to plastic collapse and excessive localized plastic deformations, with considerations and proposals related to internationally recognized normative criteria. Dynamic analyses, considering complete nonlinearity, are conducted to assess susceptibility to dynamic buckling induced by wind when non-deterministic behavior is considered. Among the various conclusions of this work, it is highlighted that the non-deterministic dynamic behavior of wind can lead deformed tanks to dynamic structural instability, and structural reinforcement elements can be of great help in restoring buckling resistance, increasing the latter by an average of up to 711%.
Instituição: Universidade do Estado do Rio de Janeiro
Tipo do documento: Tese2023-12-15T00:00:00ZAnálise de falha por fratura em mola de carro torpedo: estudo de caso
http://www.bdtd.uerj.br/handle/1/20162
Título: Análise de falha por fratura em mola de carro torpedo: estudo de caso
Autor: Rocha, Juliana Modesto de Andrade Machado da
Primeiro orientador: Diniz, Marília
Abstract: This paper analyzed the possible causes that led to the premature failure of a spring that made up a torpedo truck, a vehicle used to transport pig iron from the blast furnace to the steelworks of a large steel mill. For this purpose, optical microscopy (MO), scanning electron microscopy (SEM), semi-quantitative chemical analysis by Energy Dispersive Spectroscopy (EDS), quantitative fluorescence chemical analysis, Vickers microhardness test (HV), Rockwell hardness at the N measuring scale (HR) and residual stress analysis measured by X - ray diffraction in the region where the fracture occurred were used. The industrial quenching, tempering heat treatments and shot peening were also redone for the spring under analysis, all in order to simulate the treatments that were supposedly done on the original spring. Comparing the results, it can be concluded that the process that led to spring fracture was a mechanism of fatigue failure originated from a defect in the spring surface. Although residual stresses on the spring surface were as expected to prevent fatigue failures from surface defects, the hardness in this region of the material was lower than specified due to a decarburizing process.
Instituição: Universidade do Estado do Rio de Janeiro
Tipo do documento: Dissertação2019-12-19T00:00:00ZAnálise dinâmica não determinística e otimização estrutural do projeto de torres de aço para suporte de turbinas eólicas
http://www.bdtd.uerj.br/handle/1/20026
Título: Análise dinâmica não determinística e otimização estrutural do projeto de torres de aço para suporte de turbinas eólicas
Autor: Castilho, André Victor da Silva
Primeiro orientador: Silva, José Guilherme Santos da
Abstract: Given the growing demand for electricity and the urgent need to reduce greenhouse gas emissions, the use of energy from renewable sources has experienced significant growth in recent years. Among renewable energy sources, given its technological development and competitive prices, wind energy plays a fundamental role in the global transition towards a decarbonized energy matrix. In this context, this research work aims to perform the structural optimization of a steel tower designed to support a wind turbine with a production capacity of 2 MW, considering constraints on natural frequency, horizontal displacement, allowable stress and buckling resistance. The analysis of the structural response of the steel tower is performed using a three-dimensional finite element model that takes into account the wind loads on the rotor, the nondeterministic dynamic effect of the wind on the structure and its interaction with the ground. The proposed optimization process is performed through na interaction between a finite element software and an open source genetic algorithms library. Due to the nature of the mathematical formulation presented for the dynamic effect of the wind, a statistical analysis of the dynamic response of the structure as well as the results of the nondeterministic optimization is performed, aiming to obtain results within a 95% confidence interval. In order to present a basis of comparison for the presented results of the optimization process, an analysis of the structural behavior of the steel tower under the static and dynamic action of the wind is performed. Based on the results, it was demonstrated that the optimization process under the non-deterministic effect of the wind leads to a project whose volume is 31.3 % below the original volume and only 4.6% above the project obtained considering its static effect. However, it was found that the optimized model in this work has a greater robustness to the uncertainties associated with the dynamic effect of the wind on the structure.
Instituição: Universidade do Estado do Rio de Janeiro
Tipo do documento: Dissertação2023-02-28T00:00:00ZAnálise da ação bactericida de selante de matriz polimérica com aditivo de prata
http://www.bdtd.uerj.br/handle/1/19368
Título: Análise da ação bactericida de selante de matriz polimérica com aditivo de prata
Autor: Rocha, Ully Guimarães
Primeiro orientador: Chalhub, Daniel José Nahid Mansur
Abstract: The aim of this project was to analise and characterize some properties of polymeric surfaces based on PLA, uncoated and coated with a polymer matrix sealant with Silver Nitrate aditives. The methodology included the fabrication of PLA plates by additive manufacturing (3D printing) and the creation of a sealant model to cover these samples silver-based. Techniques like visual inspections, optical microscopy (OM), digital image processing (DIP), scanning electron microscopy (SEM), semi-quantitative chemical analysis by energy dispersive spectroscopy (EDS) and average roughness (Ra) were used to characterize the surfaces. In vitro tests were carried out to analyze the effect of the surfaces and quantify the growth of the bacteria Escherichia coli ATCC 11229 and Staphylococcus aureus ATCC 25923. The results obtained showed a a reduction in the number of bacteria of approximately 64x for the silver-based material after 30 minutes of contact with the sealant surface, when compared to the non-coated surfaces.
Instituição: Universidade do Estado do Rio de Janeiro
Tipo do documento: Dissertação2022-12-19T00:00:00Z