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La interacción estática suelo-estructura puede considerarse como la mutua transmisión de esfuerzos y deformaciones entre ambos, en este entendido se ha realizado el análisis paramétrico de la interacción suelo-estructura en una cimentación superficial aislada por el método de elementos finitos, con el objetivo de determinar los principales esfuerzos actuantes en estado de servicio, establecer cuáles son las variables con mayor relevancia y proponer valores que garanticen mayor eficiencia en el desempeño de la cimentación. Por medio de los modelos numéricos, elaborados con la versión estudiantil del software ABAQUS CAE, se ha analizado la incidencia del tipo de suelo y forma de la cimentación en los esfuerzos producidos por la interacción suelo-estructura, donde se ha determinado la importancia del área de la cimentación en el cálculo de la capacidad portante del suelo; asimismo, se ha establecido como la estructura de cimentación retiene dentro de sí una parte de los esfuerzos producidos por la estructura per sé, transmitiendo menores esfuerzos al suelo que lo calculado teóricamente.

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The present work consists of proposing a new design of balloon-expandable aortic valve stent for use in patients with aortic valve stenosis. Finite element simulations were carried out to determine the Von Mises stresses and deformations and thereby select the design parameters of this device, which will allow its manufacturing and proper operation. The symmetrical condition of the stent facilitated the modeling process, as well as the determination of the smallest reduced diameter of the stent, a necessary condition for it to be moved safely within the artery. In this analysis, 316L stainless steel was used, an elastoplastic, isotropic and homogeneous behavior of the material was considered, also varying the thickness and radius of curvature at the ends of the stent sections. Loads were applied at the joints of these sections, obtaining equivalent stresses below the resistance limit of the material and above the elastic limit. The greatest reduction in stent diameter was obtained with a wire thickness of 0.5 mm and a radius of curvature of 0.5 mm. The mean diameter of the open device (22.987 mm) was reduced to 7.65 mm when applying a pressure of 43.8 MPa. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study on the mechanical behavior of buried pipes subjected to thermal load cycles. Firstly, stresses and deformations are measured experimentally on a buried pipe subjected to monotonic and cyclic thermal loads, hence reproducing the typical operating conditions of buried piping systems. Subsequently, a numerical model is developed using the finite element method, which is validated using the results obtained experimentally. Subsequently, this computational model was used to carry out a parametric study of the influence of the mechanical properties of the soil on the stress state of the system. Finally, from the results obtained experimentally and numerically, it is concluded that the most critical situation in terms of stresses takes place when the pipe is firstly placed into operation, i.e. in the first cycle of thermal load and the other variables studied have little impact. [ABSTRACT FROM AUTHOR]

Due to their high resistance to corrosion, fatigue and low specific weight, composite materials have been developed as an excellent alternative to replace traditional materials. They are used in fluid transportation, rehabilitation, and repair of in-service pressure systems and are relatively easy to use in the industrial sector. This work presents the state-ofthe-art in repair systems using composite material reinforcement. First, it classifies the systems, showing those available in the market, and compares them regarding their mechanical properties and application processes. The second section presents and compares the design standards ASME PCC2 and ISO 24817. Finally, it discusses the experimental and simulation techniques used for their study. The work concludes by showing the future possibilities and challenges that composite repair systems face in their adoption. [ABSTRACT FROM AUTHOR]

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Tras el sismo de Northridge en 1994, mismo que ocasionó daños significativos a las estructuras de madera, la investigación sobre la respuesta sísmica de muros de entramado ligero ha experimentado un notable crecimiento. Este interés se ha extendido más allá de la zona afectada. Autores de países con tradición constructiva en madera han experimentado sobre la geometría de los componentes del muro, la conexión entre el marco y el panel de revestimiento y la implementación de nuevos materiales. En complemento a la parte experimental se han desarrollado modelos numéricos que capturan de forma precisa el comportamiento ante carga sísmica. Este artículo de revisión del estado del arte tiene como objetivo sintetizar las innovaciones y hallazgos encontrados durante la última década, mismos que se detallan en artículos de investigación disponibles en la base de datos ScienceDirect, haciendo de este trabajo una referencia inicial para explorar futuras líneas de investigación en países donde este sistema no ha sido mayormente divulgado. Se ha adoptado la metodología indicada en la declaración PRISMA para dar un adecuado diagnóstico de la información bibliométrica encontrada, adicionalmente se realizaron mapas bibliométricos basados en autores empleando la herramienta VOSviewer. Cabe señalar que en este trabajo se han excluido aspectos de resistencia al fuego u otros factores ambientales. La presentación de los resultados se organiza en función de dos aspectos clave identificados en la literatura: los estudios experimentales y la modelación numérica de muros de entramado ligero.

This paper presents an experimental study on the mechanical behavior of buried pipes subjected to thermal load cycles. Firstly, stresses and deformations are measured experimentally on a buried pipe subjected to monotonic and cyclic thermal loads, hence reproducing the typical operating conditions of buried piping systems. Subsequently, a numerical model is developed using the finite element method, which is validated using the results obtained experimentally. Subsequently, this computational model was used to carry out a parametric study of the influence of the mechanical properties of the soil on the stress state of the system. Finally, from the results obtained experimentally and numerically, it is concluded that the most critical situation in terms of stresses takes place when the pipe is firstly placed into operation, i.e. in the first cycle of thermal load and the other variables studied have little impact.

Debido a su alta resistencia a la corrosión, la fatiga y el bajo peso específico, los materiales compuestos se han desarrollado como una buena alternativa para reemplazar los materiales tradicionales. Se utilizan en el transporte de fluidos, en la rehabilitación y reparación de sistemas a presión en operación y son relativamente fáciles de usar en el sector industrial. Este trabajo muestra el estado del arte en los sistemas de reparación que utilizan reforzamiento de materiales compuestos. Primero, clasifica los sistemas, mostrando los sistemas que están disponibles en el mercado y los compara en términos de sus propiedades mecánicas y procesos de aplicación. En un segundo momento, se presentan y comparan las normas de diseño ASME PCC2 e ISO 24817. Finalmente, se muestran las técnicas experimentales y de simulación utilizadas para su estudio. El trabajo concluye mostrando las posibilidades futuras y desafíos que enfrentan los sistemas de reparación de compuestos en su adopción.

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Este trabalho é parte de uma pesquisa a nível de doutorado finalizada em 2022 no Programa de Pós-graduação em Matemática Aplicada da UNICAMP. O texto aqui apresentado é uma solução numérica aproximada para a Equação de Navier-Stokes, em sua forma desacoplada via método das projeções de Chorin-Temam. Utilizamos o MATLAB em uma implementação paralelizada, com possibilidade de escolhas dos processadores para realizarmos os testes. A malha foi gerada com o auxílio do software GMSH em sua forma não estruturada, donde refinamos bem para obtermos resultados mais precisos. A validação foi baseada nos experimentos publicados por Lienhard (1966), citado por Blevins (2001), para o caso do duto cilíndrico, donde respeitamos as classificações dadas para os diferentes números de Reynolds.

This study is the second part of a previous work recently published about the optimization a new facility for convective heat phytosanitary treatment system applying the heat of exhaust gases from a distillery boiler as energy source for the pallets thermal disinfection. In the mentioned work, a control volume element of 3D finite heat transfer mathematical model was applied and correlated with experimental data in order to study the optimal operational conditions of air temperature and retention time when block-type pallets are thermally treated. However, optimal conditions for the phytosanitary treatment of the stringer-type pallets (the second more used in world-wide trading operations) in the presented facility has not been assessed so far. This case study presents the development and application of a control volume element model of 2D finite heat transfer mathematical model to optimize the operational parameters for the phytosanitary treatment of stringer-class wood pallets. The optimization of treatment temperature and retention timeissimulated based on previous findings reported. Optimal conditions were found for stringer-type pallets withair temperature at 80°C and 95 min of treatment time. The thermal efficiency, the energy consumption index of per treated pallet at the studied conditions and the economic feasibility of the new treatment system is discussed. [ABSTRACT FROM AUTHOR]

Se determinaron las tensiones de soldadura en una unión de tubería fabricada de acero austenítico AISI 316 a través de los cálculos de resistencia y del método de los elementos finitos (MEF). A partir de tuberías de 250 mm de diámetro, se consideró las tensiones generadas por las temperaturas, así como las equivalentes y las deformaciones. Se determinó que, a partir de la composición química del cordón resultante donde se analizó los elementos alfágenos y ganmángenos que la solidificación es de Ferrita-Austenita, que las tensiones y deformaciones determinadas, resisten las temperaturas y las presiones de trabajo, todos en conjunto no provocan el fenómeno de la rotura en la unión de tubería. Los resultados fueron corroborados a través del método de los elementos finitos (MEF) donde se comprobó que dichas tensiones no superan el límite de la fluencia del material base y que las deformaciones existentes son producidas por la temperatura y la presión de trabajo.

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Cantoneiras enrijecidas de aço formadas a frio podem apresentar três modos críticos de instabilidade. Entretanto, barras em seção composta podem apresentar outros modos de acordo com o tipo, a disposição e a configuração das conexões. Barras compostas em dupla cantoneira com travejamento em quadro são constituídas por duas seções idênticas, dispostas de forma paralela e ligadas, em apenas alguns pontos ao longo do seu comprimento, por chapas separadoras. Apesar de ser um sistema bastante utilizado, não existem especificações nas normas para dimensionamento preciso desse componente estrutural. Posto isso, este trabalho objetivou avaliar a influência da inserção de travejamentos ao longo do comprimento na força normal resistente das barras compostas e verificar se os resultados obtidos estão compatíveis com os das hipóteses adotadas com base nos procedimentos normativos. Para tanto, foi realizada uma análise numérica não linear pelo Método dos Elementos Finitos no software Ansys, utilizando-se seções caracterizadas experimentalmente e disponíveis na literatura. Nesse sentido, observou-se que a adição de chapas separadoras aumentou significativamente a força normal resistente dos elementos, sendo os arranjos com uma ou duas chapas os mais efetivos. Os resultados foram intermediários, considerando as normativas adotadas, e indicaram a necessidade a necessidade de um modelo de cálculo próprio para o arranjo de cantoneiras enrijecidas compostas, ligadas por travejamentos em quadro.

Introduction and objectives: Distal femoral fractures represent a problem due to their high number of complications. The aim was to compare the results, complications and stability achieved with retrograde intramedullary nailing and the angular stable plate in the treatment of distal femoral diaphyseal fractures. Material and method: A clinical and experimental biomechanical study was carried out using finite elements. The results of the simulations allowed us to obtain the main results related to the stability of osteosynthesis. For clinical follow-up data, frequencies were used for qualitative variables, and Fisher's exact test and χ2 test were used to evaluate the significance of the different factors, with the condition of P

Copyright of Revista Fatec Zona Sul (REFAS) is the property of Revista Fatec Zona Sul (REFAS) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper proposes a semi-analytical methodology that combines the asymptotic homogenization method (AHM) with the finite elements method (FEM) to solve boundary-value problems with rapidly oscillating coefficients. This approach is motivated by the convergence difficulties observed when this type of problem is addressed directly via FEM, whereas the AHM has shown to be efficacious for obtaining good generic approximations of the exact solution. Illustratively, this AHM-FEM methodology is developed for the mechanical equilibrium problem of a radially microperiodic orthotropic sphere under hydrostatic pressure, which allows its validation by comparing with the AHM analytical solution. Specifically, the effective coefficients and the homogenized and local problems are calculated via AHM, and then their analytical and FEM solutions are obtained. Finally, to validate the semianalytical methodology, the generic solutions are applied in an example and, from the obtained results, a comparison is made between the analytical AHM solution and the semi-analytical AHM-FEM solution. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Research & Development / Revista de Investigación & Desarrollo is the property of ECORFAN-Mexico S.C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Las diversas alternativas utilizadas dentro de la industria de la construcción hacen que en el análisis y diseño estructural se emplee varias herramientas para conocer el correcto comportamiento de las estructuras ante estados de carga de diferente índole. Como consecuencia de ello se presenta un estudio del comportamiento de las cubiertas planas autoportantes y su conexión con las vigas laterales, mediante la aplicación del método de elementos finitos dentro de un análisis lineal con la ayuda del software ANSYS Workbench. Para ello se utilizó una sección IMAP-800 conformando cubiertas con luces de 10, 20, 30 y 40 m, complementado el análisis con vigas y columnas tipo celosía, para el soporte de fijación se empleó una pletina con espesores de 4 a 12 mm, con la finalidad de comparar con las guías de diseño nacionales e internacionales, como son espesor, pendiente, luz máxima y la geometría del soporte de fijación. Observando esfuerzos máximos cerca de los soportes de fijación, mientras que las deformaciones máximas tuvieron lugar en los extremos de la cubierta. Al establecer nuevos parámetros para salvar las luces correspondientes, demostró un aumento en el peso de la cubierta alrededor del 5 % con relación a las guías de diseño empleadas.

Se considera el problema del diseño de redes de transporte, conociendo la topología factible y la matriz origen-destino de viajes. El objetivo de este trabajo es obtener las capacidades de los tramos de la red que permiten satisfacer las demandas de pasajeros (o vehículos), minimizando tanto sus recorridos de viaje como el costo de construcción. Para ello, se propone un modelo matemático, basado en una analogía con el comportamiento de aprovisionamiento de un organismo biológico (Physarum Polycephalum), consistente en un procedimiento iterativo que converge al denominado “óptimo del sistema” de transporte. Adicionalmente, se combina esta metodología con una técnica de reducción de variables, basada en el “Método de Elementos Finitos” para minimizar el tiempo de cálculo computacional requerido al analizar grandes redes.

El presente trabajo realizado en el mes de mayo del 2021, en la Universidad Politécnica Salesiana con Sede en CUENCAECUADOR, se propone evaluar el diseño de partes de una plegadora hidráulica sometidas a una fuerza máxima de compresión que deben soportar los materiales a través de cálculos matemáticos y análisis estático de elementos fi nitos utilizando la herramienta SolidWorks en los aceros comerciales, por la norma de la Sociedad Estadounidense para Pruebas y Materiales, ASTM A36, la norma del Instituto Americano del Hierro y el Acero AISI SAE 1020 y AISI SAE 1045. El principal objetivo de este estudio se lo realizó en los componentes que están expuestos a esta fuerza, lo que dió como resultado el mejor espesor con respecto al factor de seguridad para la construcción estructural, produciendo deformaciones menores en los parámetros de esfuerzo máximo de compresión, fl exión y pandeo. Los resultados revelan que la menor deformación en base a los criterios antes mencionados se obtuvo para el acero SAE 1045, y es de 0.19 mm para el punzón y 0.04 para la matriz de plegado, por lo tanto, se debe de optar para la construcción de los diferentes elementos utilizados en esta investigación, siendo este, analizado bajo las mismas condiciones iniciales. Finalmente, con los resultados obtenidos, se ha determinado el material y espesor óptimos para la construcción de los diferentes elementos principales de la máquina.

This paper presents a study of magnetic flux density in a large synchronous large size machine when it is working as a generator. Finite elements software has been used to obtain the same physical and electrical characteristics of the real machine. From the results conveyed from the simulations, it is possible to find the optimal points where the magnetic flux sensors will be placed and to determine short-circuit faults in the rotor coils. The work results are also a reference to evaluate and compare the magnitudes taken by the sensors without creating short-circuits in the actual machine coil. Besides that, the proposed model based on finite elements can be used to make simulation tests of new kinds of sensors. [ABSTRACT FROM AUTHOR]

Este trabalho desenvolve um modelo para quantificar o nível de descargas parciais (DP) em cavidades ocluídas em sistemas de isolação de geradores. O modelo baseia-se na teoria de campo e usa o Método dos Elementos Finitos (MEF) para resolver as equações de campo. A simulação desenvolve-se em dois passos: no primeiro passo simula-se a situação anterior à descarga parcial, em que não existem cargas espaciais no interior da cavidade, pela resolução das equações de Laplace. Já o segundo passo simula a situação logo após a ocorrência da DP, resolvendo-se as equações de Poisson, simulando a existência das cargas espaciais criadas durante o tempo de descarga. As simulações indicam uma diferença de 2,14% entre os níveis de DP medido e calculado para uma delaminação na isolação de uma barra estatórica. Com base nesse resultado, o modelo é capaz de estimar o nível de DP para defeitos localizados no sistema de isolação de estatores de hidrogeradores.

As vigas de Madeira Lamelada Colada (MLC) têm sido amplamente empregadas em estruturas que exigem o uso de vãos e formas não convencionais. Em casos que são requeridos elementos estruturais com maior resistência e/ou rigidez, o uso de reforço estrutural pode ser necessário para que os elementos atendam aos requisitos de projeto. Entretanto, as normas brasileiras não contemplam um método para análise e dimensionamento de elementos de madeira reforçados por fibras. Nesse sentido, este trabalho visa avaliar a confiabilidade estrutural do dimensionamento de vigas de MLC da espécie Pinus taeda reforçadas com fibras de Vectran® via método dos elementos finitos. Simulações numéricas foram realizadas através do software ANSYS®, tendo como parâmetros de resistência e rigidez para a viga aqueles estabelecidos pela norma brasileira de estruturas de madeira e a teoria dos volumes para estimar os parâmetros físico-mecânicos para reforço com fibras. A probabilidade de falha do dimensionamento foi aplicando a simulação de Monte Carlo por meio de um programa implementado em linguagem Matlab®. A variação das propriedades mecânicas da madeira, adesivo e fibra foi considerada nessa simulação, bem como as correlações de Pearson entre elas. Constatou-se que a aplicação do reforço melhorou as capacidades de resistência nos estados limites últimos e de serviço. Além disso, os carregamentos médios limites produzidos pelos modelos normativos demonstraram-se mais conservadores quanto ao estado limite último, comparado ao método probabilístico.

Neste artigo o método multigrid algébrico baseado em agregação suavizada, o método clássico de Ruge-Stüben e o método GMRES pré-condicionado por multigrid algébrico foram utilizados para a solução da equação do fluxo livre estacionário em domínio georreferenciado. A disponibilidade dos códigos computacionais permitiu avaliar a aproximação de elementos finitos sob a perspectiva dos métodos multigrid algébricos e respectiva combinação, como pré-condicionante, com o método GMRES. As diferenças máximas entre soluções por diferentes métodos, o tempo necessário para obter as soluções dos sistemas lineares associados em cada uma das iterações de Picard, os residuais de cada um dos métodos iterativos e os resíduos em cada uma das iteradas de Picard são apresentados e discutidos. Como resultado da análise, os método pré-condicionados são mais eficientes no sentido do menor tempo computacional aliado à estabilidade do número de iterações. A análise dos resíduos das iterações de Picard permite comparar a evolução dos diferentes métodos de solução dos sistemas lineares. O detalhamento dos residuais dos métodos iterativos em cada passo das iterações de Picard permitiu uma visão mais abrangente e uma análise da convergência. Em detalhes, o método baseado em agregação suavizada necessita de um número expressivamente menor de iterações quando comparado ao método clássico de Ruge Stüben nas primeiras iterações de Picard. O pré-condicionamento reduz o número de iterações em relação às iterações iniciais e há uma persistência da redução do número de iterações do método baseado em agregação em relação ao método clássico.

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As an application of geotechnical engineering, an analysis of portal stability of the exit of Tunnel 3, in the construction of the double lane central section "El Sillar" Cochabamba - Santa Cruz highway is presented. This study is carried out by using the finite element method FEM with the PLAXIS 3D software to determine the areas where slope stabilization of the portal is needed and the definition of the excavation construction method along with the support system for the tunnel. Later, the tunnel structure is evaluated. Initially, data compilation from geotechnical studies is done (pits, geomechanical stations, geophysical survey, in situ and laboratory tests on drilled rock cores) contrasted with proper bibliographic referenced ranges to obtain initial geomechanical conditions. Subsequently, mechanical parameters of the rock are calibrated by means of real deformations caused by the excavation of the tunnel in the portal with a plastic-type calculation. The calibrated model achieves the average measured deformation on the tunnel: 5 mm. Then, the stability analysis is carried out by means of a safety-type calculation to obtain global safety factors where different stabilization alternatives are assessed. In this way, the modification of the slope geometry is revealed as the most optimal solution. Subsequently, the construction stages of the tunnel are simulated by adopting the Belgium method, the largest number of supports is required, because it is a very unstable area. Finally, principal effective stresses and deformations for static and pseudo-static conditions are calculated and reach admissible values (6, 12 mm maximum deformation in the vault) and minimum safety factors were above minimum factors required by NSR-10: 1,25 and 1,0; assessing most optimal geometry considering reinforced and non-reinforced conditions in the tunnel at three different depths and lateral covers for the tunnel.

La unión viga-columna de hormigón armado es una región crítica en el sistema aporticado debido a las funciones estructurales que cumple y condición de cargas a las que está sometida. Su geometría reducida y la interacción entre los materiales de los que está compuesta generan un comportamiento no-lineal sensible a muchas variables. En este estudio se analiza el comportamiento mecánico de la unión viga-columna en Estado Límite de Servicio (ELS) mediante un modelo numérico de elementos finitos. Se presenta una comparación entre los resultados obtenidos y los reportados por otros autores (experimentales y numéricos) para poder validar el modelo numérico desarrollado. Los resultados muestran que la propagación de fisuras debido al momento flector negativo de la viga reduce significativamente la rigidez de la unión viga-columna en etapas iniciales de carga y produce un aumento de tensiones en el núcleo de la unión. Para controlar esta propagación en los modelos simulados se propone la incorporación de estribos abiertos ubicados en la mitad superior de la altura de la viga.

Este documento presenta la evaluación estructural del cuerpo de una aeronave ligera de categoría vla (masa máxima al despegue inferior o igual a 1200 kg), usando sofware de dinámica computacional de fluidos (CDF) para evaluar el comportamiento aerodinámico de la aeronave y el método de elementos finitos para evaluar su comportamiento estructural. Para su evaluación estructural la aeronave se dividió en cabina, cuerpo y superficies de vuelo (alas y empenaje). Los modelos completos de la aeronave fueron extraídos del modelo cad, elaborado con el sofware SolidWorks® para cada uno de los subcomponentes de la cabina, el cuerpo y las alas y el empenaje. A partir de los cálculos y simulaciones hechas, se concluyó que la estructura central de la aeronave soporta las fuerzas y momentos aerodinámicos, con valores de esfuerzos por debajo de los valores de fluencia del material y factores de seguridad entre 1.58 y 2.60. Sin embargo, se necesita reforzar la unión del ala al fuselaje para que disminuya el esfuerzo localizado que se produce en esa zona. A diferencia de otros métodos reportados en la literatura que utilizan programas muy especializados y de altos costos, el procedimiento para evaluar la aerodinámica y la estructura central de una aeronave liviana categoría VLA que se desarrolló en este estudio, hizo uso de programas de dominio público, en alrededor de 80 % en el proceso de análisis.

Los generadores de flujo axial son máquinas utilizadas en sistemas de generación eólica, y dado el creciente interés por las energías renovables a pequeña escala se requiere buscar nuevas configuraciones que permitan enfrentar el aumento de las necesidades energéticas a nivel mundial. En este documento se analiza la selección, diseño y simulación de tres topologías de un generador de imanes permanentes de flujo axial de doble rotor para aplicaciones de baja velocidad y baja potencia (10 watios), las cuales se modelan aplicando el método de elementos finitos en el software COMSOL 2D, como aporte al proyecto de investigación Topologías de Generador Eólico de Baja Potencia, gracias a este método es posible optimizar el diseño y observar la densidad de flujo magnético en los dientes del estator, entrehierro y polos magnéticos. Los resultados obtenidos se comparan tomando como referencia la potencia de salida generada bajo las cargas de 10, 40,100, 150 y 260 ohmios, además indican que las topologías 1 y 3 (puramente sin núcleo y estado ranurado) presentan un mejor comportamiento tanto en vacío como bajo carga, al buscar reducir el peso de la maquina implementado una matriz tipo HALBACH en los polos magnéticos de los rotores.

In slope stability, an important factor to be considered is the presence of tension crack. Over the years, stability has been analyzed using the limit equilibrium analytical method and more recently with the use of numerical methods. In previous investigations, the location and/or the depth of the crack were previously set. In this investigation, using the finite element method, the behavior of the failure surface in soils was simulated, the properties of the materials were established, the geometric conditions (inclination and height of the slope) were assigned, evaluating their influence on the deformation by shear, in order to visualize the appearance of the fracture surface formed by the tensile crack, and in this way its location and depth were determined. It was shown that as the geometric conditions increase, the depth of the crack increases, the location distance decreases, as does the safety factor. Finally, it is concluded that tensile cracks occur in the case of the fine soils studied, that the geometric conditions are decisive in the location and depth of the tensile crack, as well as in the stability of the slope. [ABSTRACT FROM AUTHOR]

This paper proposes the development of a 3D numerical model of the casing-cement-formation system to evaluate the mechanical tensile and shear failure of the cement at the casing-cement interface as the pressure and temperature conditions of the formation and borehole vary during production. The numerical model which includes the formation pressure, unlike others proposed, was designed by stages under finite element discretization and validated by analytical models. Results show that increasing the formation temperature increases the probability of tensile and shear failure in the cement, while increasing the wellbore temperature decreases these probabilities. On the other hand, the decrease in the well pressure reduces the probability of shear failure and increases the tensile failure. In the case of formation pressure, the opposite occurs. [ABSTRACT FROM AUTHOR]

Nowadays, construction is one of the activities with the greatest impact, the reason why it is necessary to look for materials that contribute favorably to the environment. With this premise, this article studies the implementation of recycled tire rubber as elastomeric support in simply supported beams. For this purpose, three physical models of reinforced concrete bridges with different bearing types were developed: 1) without bearings, 2) neoprene bearings, and 3) recycled rubber bearings, which were subjected to a horizontal vibration test. Subsequently, there was a development of numerical models equivalent to physical tests, and it was determined the influence of the use of recycled rubber bearings on the mechanical behavior of the structural elements. The results indicate that the implementation of recycled rubber sheets as bearings elements produces a reduction in the internal forces of the structural elements and show an increase in the displacement of the models. The obtained results allow us to conclude that recycled rubber sheets could be used in the construction of bearings for bridge structures. [ABSTRACT FROM AUTHOR]

Currently, there are different options to increase the ultimate resistance of plate girders subjected to patch loading. Some of these alternatives include the use of closely spaced transverse stiffeners and the use of longitudinal stiffeners. Nevertheless, recent investigations have demonstrated that the resistance is also improved by using delta stiffeners, which are obtained by welding two plates between the web plate and the loaded flange. This paper aims at studying the elastic buckling behavior of slender plate girders designed following AASHTO norms with delta stiffeners subjected to patch loading. The research is carried out by means of eigenvalue analysis using the finite element method. A parametric study is performed to evaluate the influence of various geometrical parameters on the buckling coefficient of the girder. Finally, design recommendations are suggested based on the obtained results. [ABSTRACT FROM AUTHOR]

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Una de las causas de fallo que con mayor frecuencia se presentan en las transmisiones por engranajes, es la conocida como fatiga superficial o picadura. Para predecir el comportamiento del material frente a este fenómeno, las normas internacionales de diseño, Asociación Americana de Manufactura de Engranajes (AGMA) y la Organización Internacional para la Normalización (ISO), formulan modelos basados en la distribución de presiones de Hertz, para el contacto entre sólidos. En esta investigación se comparan las tensiones de contacto en engranajes cilíndricos de dientes rectos, de acuerdo a lo planteado por las normas antes mencionadas, el criterio de Hertz y mediante el método de elementos finitos. Los modelos en tres dimensiones fueron obtenidos con la ayuda de un paquete de diseño asistido por computadora (CAD), donde se tuvieron en cuenta las especificaciones de cada norma. Como una de las variantes de cálculo a comparar, es el resultado obtenido por simulación numérica, solo se tendrán en cuenta los factores que dependan de la geometría del diente y el material del mismo. Los resultados obtenidos se analizaron estadísticamente, donde se determinó la efectividad del método de elementos finitos para este tipo de cálculo, además, estos se asemejan más a los obtenidos por método de Hertz que es la teoría que sirve como base a las normas antes mencionadas.

En la estabilidad de taludes, un factor importante a considerar es la presencia de grietas de tracción. Con los años, la estabilidad se ha analizado utilizando el método analítico de equilibrio límite y más recientemente con el uso de métodos numéricos. En investigaciones anteriores, la ubicación y/o la profundidad de la grieta, se fijaron previamente como un dato conocido. En esta investigación, utilizando el método de elementos finitos, el comportamiento de la superficie de rotura, se simuló con la presencia de grietas de tracción en suelos, considerando la influencia de las condiciones geométricas (inclinación del talud y altura), así; se determinaron entonces la ubicación y profundidad de la grieta de tracción. Finalmente, se concluye que se producen grietas de tracción en el caso de los suelos finos estudiados, a medida que la inclinación y la altura del talud aumentan, la distancia desde la base del talud a la grieta disminuye, la profundidad de la grieta aumenta y por consiguiente, el factor de seguridad disminuye, que resulta un factor determinante en la estabilidad del talud.

En la actualidad, el sector de la construcción es una de las actividades con mayor impacto, razón por la cual es necesario buscar materiales que contribuyan favorablemente al medioambiente. Con esta premisa, en el presente artículo se estudia la implementación de caucho de neumático reciclado como apoyo elastomérico en vigas simplemente apoyadas. Para tal fin, se desarrollaron tres modelos físicos de puentes de concreto reforzado con diferentes tipos de apoyo: 1) sin apoyos, 2) apoyos en neopreno y 3) apoyos en caucho reciclado, los cuales se sometieron a una prueba de vibración horizontal. Posteriormente, se desarrollaron modelos numéricos equivalentes a los ensayos físicos, y se determinó la influencia del uso de apoyos de caucho reciclado en el comportamiento mecánico de los elementos estructurales. Los resultados indican que la implementación de láminas de caucho reciclado como elementos de apoyo produce una reducción en los esfuerzos internos de los elementos estructurales y un aumento en los desplazamientos de los modelos. Dichos resultados permiten concluir preliminarmente que las láminas de caucho reciclado pueden ser utilizadas en la construcción de apoyos de estructuras de puentes.

En la actualidad existen diferentes opciones para incrementar la resistencia última de vigas esbeltas sujetas a cargas concentradas. Algunas de estas alternativas incluyen el uso de rigidizadores transversales cercanamente espaciados y la utilización de rigidizadores longitudinales. Sin embargo, estudios recientes han demostrado que la resistencia también mejora mediante el uso de rigidizadores tipo delta, los cuales consisten en dos láminas soldadas entre alma de la viga y la aleta cargada. Este trabajo se enfoca en el estudio del comportamiento de pandeo elástico de vigas esbeltas diseñadas con normas AASHTO con rigidizadores tipo delta sometidas a carga concentrada. El estudio se realiza a través del análisis de autovalores usando el método de elementos finitos. Se realiza un análisis paramétrico para determinar la influencia de diferentes variables geométricas sobre el coeficiente de pandeo de la viga. Finalmente, a partir de los resultados obtenidos se sugieren algunas recomendaciones de diseño.

Nowadays, the use of the CubeSat standard for satellites design has become a strong appliance in space industries and universities because of its low cost. In its simpler model a CubeSat, consists of a cubic nanosatellite with less than 1,33 kg and 10 cm of edge. The present work was done computational simulations using the finite element method since computational simulations are cheaper to do vibration tests. It was carried out modal analyses comparing five CubeSat structures, where it was evaluated the presence of electronic board (without electronic elements), static loads, two different aluminum alloys, and the influence of additional mass in the PCB (Printed Circuit Board). CAD software was used for the structures' design following the CubeSat specifications, and all the simulations were carried out in a finite element software, in a range of 0 to 1000 Hz. It was designed one structure to do initial simulations, followed by the design of 4 structures more adjusted to the CubeSat requirements. In the end, results showed the influences of each present condition on the satellite. It was noticed that influences of the load in the vibration shape and less than 2% in other results. The material available to build a CubeSat for tests was validated concerning the recommended aluminum alloy. [ABSTRACT FROM AUTHOR]

Objective: Design the landing gear for a CESTOL type aircraft according to FAR 23 using: (i) the conceptual designs of the nose and main gear and (ii) evaluate the structural strength of the design by means of finite element analysis at a stage of landing. Materials and methods: The initial requirements for the theoretical development of a preliminary landing gear design are used as a case study. The aircraft's structure is taken as a base for the different design stages. This analysis is according to a static and level landing condition selected on each gear with a side and supplementary load. Additionally, calculations of geometric parameters and mechanical resistance with preselecting materials for the component analysis to determine and compare theoretical results with finite elements to evaluate the reliability of the design approach. Results and discussion: It is determined to move the main landing gear backward near the cargo area. That allows for better aircraft performance, placing the GC in front of the main gear and avoiding an overturn. However, this load percentage changes in proportion to the longitudinal stability criterion, where it generates an increase in the contribution to the mechanical stress in the structure of the gear. Conclusions: Results obtained about stability, controllability, and structural analysis are acceptable for the regulations of FAA Part 23 with standards associated with airworthiness, being corroborated with theoretical analysis and combined loads. [ABSTRACT FROM AUTHOR]

The increasing use of stainless steel in construction has led to the need of developing resistance models for structural elements made of this material. Unlike carbon steels, stainless steel alloys exhibit stress-strain curves with a pronounced strain hardening capacity and reasonable ductility that should be considered in the design. This difference in behavior makes the formulations used for carbon steel conservative when designing with stainless steel. Therefore, this paper presents a comparative analysis of resistance models for slender austenitic stainless-steel beams subject to concentrated loads. First, the failure mechanisms of stainless-steel beams are presented using a nonlinear finite element model. From this validated numerical model, a database obtained from a parametric analysis that covers a wide range of geometries is presented. Subsequently, this database is used to perform a comparison between various resistance models available in the literature. These models correspond to both international design codes and models obtained through machine learning. Finally, the numerical results show considerable improvement in the predicted ultimate resistances for slender stainless steel plate girders subjected to patch loading. [ABSTRACT FROM AUTHOR]

Copyright of Revista Sul-Americana de Engenharia Estrutural is the property of Revista Sul-Americana de Engenharia Estrutural and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)