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Introduction: The finite element method has become popular to determine fracture mechanics parameters, but this type of numerical analysis may or not lead to accurate results, depending on the model quality and the implementation of the established methods. Objective: Implement and validate the calculation of the stress intensity factor and the J integral through the displacement extrapolation, domain integral and interaction integral methods, through finite element modeling of cracked part problems in 2D and 3D. Materials and methods: The stress intensity factor and the integral J were calculated in a compact cracked specimen and a plate with a semi-circumferential surface crack, by means of 2D and 3D finite element models, and these results were verified with those obtained by means of published analytical expressions. Results and Discussion: The error of the results provided by the finite element models does not exceed 3% for the two-dimensional models and 7% for the three-dimensional ones, which demonstrates their quality and precision. Conclusions: The implementation of the calculation of the fracture mechanics parameters is considered validated, which makes it possible to extend its use in the future for constructions and equipment that present cracking in service. [ABSTRACT FROM AUTHOR]

Copyright of Técnica Industrial: Revista Cuatrimestral de Ingeniería, Industria e Innovación is the property of Fundacion Tecnica Industrial 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.)

Copyright of Revista Técnica Energía is the property of Centro Nacional de Control de Energia CENACE 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.)

Support vessels for platforms in the oil industry have operation versatility and capacity for structural modification. This article presents a proposal for the installation of a crawler crane on the main deck of a platform support vessel, which will carry out offshore maintenance operations. This proposal includes the results of the structural analysis of the main deck, considering its reinforcement with two NVA36 beams. This structural analysis incorporates the integrity of the main deck, taking into account the crane and loads through finite element method (FEM) models. The obtained results show that the main deck requires the proposed reinforcement to decrease the maximum stresses of von Mises up to 218.71 MPa for the structure of the main deck and 201.67 MPa for the reinforcement beams. These maximum stresses do not exceed the allowable and yield stresses of the main deck material. The reinforcement of the main deck that supports crawler crane allows safe operation of the offshore support vessel. [ABSTRACT FROM AUTHOR]

The methods of modelling and simulation of casting processes are carried out by means of software. This allows a reduction of time and costs in technological tests. As fundamental part of any casting mould is the feeding system, a component of the design on which the correct filling and solidification of the part depends. The aim of this work was to evaluate the feeding system of a permanent metal mould by gravity casting to obtain an aluminum alloy piston for an internal combustion engine, using CAD/CAE software for its modelling and simulation by finite elements. A modification was evaluated, simulated and proposed to provide a viable and economical solution, obtaining a satisfactory filling and solidification cycle that minimizes the current rejects of the original mould. The simulation of the proposal is in correspondence with the experiments carried out physically. [ABSTRACT FROM AUTHOR]

A methodology based on digital rock physics is proposed for a group of tomographic images taken from a core of sandstone extracted from an oil well, considering an anisotropic model of the material during the segmentation process. The rock sample, provided by the Colombian Petroleum Institute, is composed mainly of minerals such as quartz and calcite. First, a three-dimensional model is generated from the tomographic images. Then, a finite element mesh is created considering a material model that relates density and elastic modulus with the Hounsfield scale. Finally, a parametric study of the numerical model is performed and the results are compared with the reference values. Three different tests are proposed for the evaluation of elastic properties, where the minerals are studied individually (quartz and calcite) and as a composite (sandstone). The results of these tests are compared with reference values, showing difference percentages between 3 - 10% for the elastic modulus and between 0.7 - 2.1% for the Poisson's ratio. [ABSTRACT FROM AUTHOR]

This paper presents the design of a tuned mass damper (TMD) for vibration control of a simply supported metal beam. Considering the mechanical properties of commercial springs and magnetic dampers, and applying the finite element method, the feasibility of couple a TMD that allow to reduce vibrations in the beam was evaluated. This paper describes the beam mechanical properties, as well as the characteristics of the tuned mass damper. These results can be used in construction of dynamic models that promote the experimental study of structures. The equations proposed by Deng Hartog were used to identify adequate stiffness and damping. Finally, it was evaluated the performance of the TMD in vibration control under impact excitation conditions. With the implementation of this device, were obtained reductions of more than 90%. [ABSTRACT FROM AUTHOR]

Copyright of Revista Iberoamericana de Ingeniería Mecánica is the property of Editorial UNED 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.)

Mini dental implants are screws that are temporarily inserted into a patient's jaw as an anchor to generate force and move a tooth. The design of a device for the determination of the insertion torque of mini self-drilling dental implants in a porcine bone specimen is presented. The proposed mechanism does not require electric drive. The input power is given by the torque resulting from the effect of weight acting on a pulley through a rope. The device consists of three transmissions for motion transformation: transmission by pulley, bevel gear with straight teeth, and a rack-and-pinion mechanism. The latter allows the longitudinal advance while the rotation of the tool occurs, making possible the bone breaking and the insertion of the mini implant. The insertion force and the recommended speed for rack-and-pinion transmission, in addition to the efficiency of each transmission station were considered for calculating the input drive power of the device. For the case study, a tool holder suitable for mini implant brand HUBIT Co x 1.4mm was designed. Both cumulative fatigue and static designs were considered. A motion analysis for the in-contact moving parts allowed verifying that no interference is present in the proposed design. Linear motion of the screw is achieved by a sliding cotter. [ABSTRACT FROM AUTHOR]

Nowadays, the alternative energies have reached a great worldwide importance in the different applications related to the development of the energy sector, among which the solar energy, wind energy, hydraulic energy, geothermal energy and seawater energy can be named. A new technology that uses the kinetic energy from the water currents in natural and/or artificial channels and even from sea currents are the so-called hydrokinetic turbines. In this study, a review of the state-of-the-art referring to several numerical methods that can be useful when implemented to design, analyze, and optimize energy generation systems from hydrokinetic turbines is presented. [ABSTRACT FROM AUTHOR]

Copyright of Journal de Ciencia e Ingeniería is the property of Corporacion Universitaria Autonoma del Cauca 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.)

In this paper, the three-dimensional simulation of the indirect cold extrusion of aluminum is made, in which the structural static module of the ANSYS program is used. The behavior of a circular cross-section bar subjected to indirect extrusion with a square punch is studied to evaluate the characteristics of the process, varying the roundness of the punch and the coefficient of friction. To carry out the study, investigations were made about the process of forming the indirect extrusion with which the object described above was raised, which was developed using the finite element method showing as results that the indirect extrusion load is greater as the punch travels. In addition, it is concluded that the behavior of the equivalent effort of Von Mies in the work billet remains constant around the head of the punch as it penetrates the billet. [ABSTRACT FROM AUTHOR]

The electronic states of a GaAs elliptic quantum ring embedded in AlxGa1-xAs matrix are investigated by mean of effective mass approximation. The quantum ring is built with rectangular cross section (radial direction). The Schrödinger equation is solved by using finite element method. In angular direction, the amplitude of altitude is modulated, it lets to model quantum dots in the quantum ring. The electron energies are reported as a function of size ring, for both the lengths of the ellipses in the x y plane and their height (z-axis). [ABSTRACT FROM AUTHOR]

In this paper, the results of a numerical analysis to obtain the stress intensity factor in mixed mode, KI and KII, in a cracked concrete dam submitted to seismic loads are presented. The numerical model was implemented in the commercial finite element code Abaqus/Standard. Koyna dam geometry was used, including a crack parallel to the horizontal plane. In order to evaluate the importance of guaranteeing an adequate crack sealing using epoxy resin, a second parametric study was done considering partial crack sealing. The study results allow determining the cracks that endangered the dam structural integrity under seismic loads. [ABSTRACT FROM AUTHOR]

This paper is based on the design of a new implement for conservation tillage of agricultural soils, so it is necessary to calculate and design the dimensional - geometric parameters of the organs of work by using the new CAD tools as computation engineering support. Besides the design parameters of the new proposal were determined. The final results allow to have the necessary technical documentation for the manufacture of the implement, and also show that the concept of design meets the requirements of reliability, quality and technical requirements for crop development because it combines the best qualities of Paratill -- type organs of work, with the winged scarifies of multiplow type. [ABSTRACT FROM AUTHOR]

In this work a study of the cylindrical vessels in horizontal position and subject to internal pressure is carried out, where lids are one of the main components of this equipment. The Autodesk Inventor pro. 2016 is used to make the geometrical characterization of these elements: parametric solid modeler, assembles and surfaces for the mechanical design of complex parts. The different geometric forms of the lids and bottoms analyzed in this work are: flat-circular with or without flange, elliptical with different values of the K factor, torispherical with different values of the M factor and the hemispherical bottoms. Using the Finate Element Method (FEM), a comparative study is made about the behavior of the stress and strain in the different geometrical forms mentioned before, being demonstrated that although the best resistance and rigidity values are presented by the hemispherical bottoms and the best options of production by the flat-circulars, they are not the bottoms used the most in this vessels, being the elliptic bottoms those of more use. The results obtained allow optimizing the design and knowing the thickness limit in the most requested areas. [ABSTRACT FROM AUTHOR]

This work presents a numerical simulation using MEF submodeling scheme to study overall response of a tubular welded T supported at its principal ends and subjected to a load at its free end. This welded joint has a semi-elliptical crack at the toe of the weld in the saddle region. The response of the welded joint has been evaluated according to the measurement displacement line of the applied load at the free end, the strain field around the weld and the crack opening displacement. To validate the obtained results, these were compared with experimental data available in the literature. [ABSTRACT FROM AUTHOR]

The present investigation is based on the analysis of the human walk, based on the movement of the knee joint to obtain the main parameters, with this data is developed with a mono-centric joint with reference to the characteristics of a patient, A This mechanism perform static analysis by computer, to determine the safety factor, with these data are processed to the simulation of the manufacture of such knee joint. A 3D knee prosthesis is developed from design to manufacturing, this makes 80% of the total time based on the design, analysis and simulation of manufacturing, leaving only 20% to manufacture, And greatly reducing errors and production times since these generate high costs. [ABSTRACT FROM AUTHOR]

Louvers allow the air intake, illumination and avoid the penetration of rain water and sun light. The objective of this paper was to determinate the mechanical strength of the louvers' blades under the effect of hurricane wind. The Finite Element Method was used. Three different cross sections with 1500 mm of length and sheet thicknesses from 0,6 to 2,0 mm were analyzed. As results were obtained that the variants A, B and C resisted the conditions imposed to models without exceed the yield stress when 2,0, 1,2 and 1,0 mm of thickness were used respectively. The louver with the highest standardized height resisted the load conditions. [ABSTRACT FROM AUTHOR]

The finite element method is one of the most used numerical tools for engineering design. In recent years, novel numerical approximations have been proposed to extend the finite element method to meshes using arbitrary polygons. Such approximations are aimed to improve accuracy and increase the flexibility during the meshing process. However, as any approximation, they exhibit an error that requires to be quantified in order to validate the numerical results. In this paper, we present a technique to estimate the discretization error in energy norm for arbitrary polygonal finite element meshes. This recovery-based technique uses a moving least squares approach that considers constraints to represent the equilibrium equations. We use two benchmark problems to evaluate the effectivity of the error estimator, with good results both locally and globally. [ABSTRACT FROM AUTHOR]

In this work, and by using the finite element method (FEM) in two dimensional elasticity, the changes on the stress concentration factor generated by using different elements of approximation (CST, LST, Q4 and Q8) on flat plates are calculated, it is also a factor of study, if the mesh refinement in nearby to the concentrator affecting the value of the stress concentration factor. This analysis is performed by an algorithm developed in Matlab and compared with the results generated by the analytical method and Comsol Multiphysics simulations. [ABSTRACT FROM AUTHOR]

This paper presents a brief review of the existing methods to determine the stress intensity factor. Some historical aspects of fracture mechanics are presented. Then some of the methods are described, classifying them into three groups: analytical, finite element, and experimental methods. For each method, its characteristics, advantages, disadvantages, and restrictions are discussed. The reasons for the scientific community to advance in the application of the finite element method, due to its great versatility, are evident. It is clear that learning, mastering, and applying any of the methods entails a great effort. [ABSTRACT FROM AUTHOR]

Copyright of Revista Facultad de Odontología Universidad de Antioquia is the property of Universidad de Antioquia 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.)

The aim of this work is to analyze the distribution of residual stresses resulting from combination of volumetric changes due to heat gradients and phase changes occurring during the quenching process of 4340 steel cylinder. The mathematical model used for this objective uses the AC3 program for modeling thermal treatments which provides transformation curves, cooling curves, microstructure and material hardness in 20 positions between the surface and the center of the cylinder, whose results were fed into a finite element model, considering thermal-mechanical coupling and non-linear elastic-plastic behavior. The values of the physical and mechanical properties required in the model, were included taking into account the temperature dependence and the phases present, depending on the treatment time. The results of the modeling have been compared to experimental measurements of the residual stresses at the surface, through X-Ray diffraction techniques and using the sin2ψ method. The results obtained from the numerical model showed a significant correspondence in comparison with the experimental results and indicates that the most significant stresses are tangential. [ABSTRACT FROM AUTHOR]

Titanium and its alloys are the biomaterials most used to substitute the bone tissue in dental implants. Nevertheless, one of its main drawbacks is the Young's modulus mismatch with respect to that one of the bone, which produces the stress shielding phenomenon, promoting the bone resorption around the implant. One alternative to solve that problem has been the fabrication of titanium porous implants with an appropriated balance between mechanical properties, i.e. stiffness and mechanical strength. In this work, a Finite Element Analysis of the stress of a porous titanium implant is presented. A model of dense dental titanium implant was developed consisting in a ceramic crown cemented on titanium implant abutment. The results were compared with the literature to approve their accuracy, and the same boundary conditions were applied to a porous implant with 40%, 50%, 60% and 70% of porosity. The stress distributions on both the crown-implant and the implant-bone interface were investigated under static loading condition. The Young modulus was obtained for the porous implants. The better behavior face to this application was obtained with 40% porous titanium. [ABSTRACT FROM AUTHOR]

Copyright of Biomedical Engineering Journal / Revista Ingeniería Biomédica is the property of Biomedical Engineering Journal / Revista Ingenieria Biomedica 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.)

In this work it was implemented a numerical model that simulates the process of orthogonal machining of metallic materials by means of the Finite Elements Method (FEM). For the development of the model, the program Ansys Flotran was used. The material was simulated as a high viscosity fluid crashing against a solid with the cutting edge geometry. From the numerical model it was made a factorial fractionated design of experiments using Minitab software, where the selected input variables were: cutting speed, depth of cut, rake angle, density and viscosity of the fluid. The considered output variables were the velocity of chip and the position of the stagnation point. Two functional metamodels of the FEM model were made, the first one by determining the empirical equations by means of a linear regression. The second was made by establishing functions based on fuzzy logic. The experiments with both metamodels showed that the depth of cut and the rake angle have the greater influence in the chip speed and in the position of the stagnation point. The metamodel based on fuzzy logic presented a better representation between the input and output variables. [ABSTRACT FROM AUTHOR]

Copyright of Revista Electrónica Redes de Ingeniería is the property of Universidad Distrital Francisco Jose de Caldas, Facultad de Ingenieria 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.)

Copyright of Revista Electrónica Redes de Ingeniería is the property of Universidad Distrital Francisco Jose de Caldas, Facultad de Ingenieria 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 presents the development of a numerical study performed to analyze the ground surface behavior due to the construction of tunnels in soft soils, specifically in the case of typical stratigraphy of the alluvial zone of Bogotá. A finite element platform PLAXIS 3D TUNNEL® was used to determine the relationship between the settlement and the tunneling excavation with TBM in this type of soil. The levels of impact in the settlement phenomenon were studied by five factors: the constitutive model of soil materials, the depth of excavation, the performance of the TBM, the diameter and thickness of the tunnel lining. The research concluded the following result: the most influential factors in the magnitude of the settlement phenomenon are the tunnel diameter and the depth of excavation. [ABSTRACT FROM AUTHOR]

Copyright of Revista Facultad de Odontología Universidad de Antioquia is the property of Universidad de Antioquia 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.)

Actualmente los proyectos de ingeniería que involucran el diseño de sistemas electromecánicos o de procesos requieren su análisis por el método de elementos finitos (MEF) para predecir y validar su comportamiento. Por ello, es fundamental que los estudiantes de diferentes áreas de ingeniería conozcan bien las bases del método para que resuelvan problemas de manera efectiva en el ámbito profesional. En este artículo se presenta el software didáctico FIMEF para apoyar en la enseñanza del método de elementos finitos (MEF), aplicado al análisis estático lineal de armaduras en 2-D. El software fue desarrollado en Matlab, tiene una interfaz amigable, la introducción de datos es sencilla y la presentación de resultados es similar a lo que ofrece cualquier software especializado. FIMEF hace especial énfasis en el aprendizaje de la metodología de cálculo presentando un reporte con la solución completa de las armaduras analizadas. Su funcionalidad y precisión fueron validadas con los resultados obtenidos por el software Autodesk Simulation Multiphysics. FIMEF será utilizado por estudiantes de ingeniería mecánica, mecánica eléctrica, mecatrónica y civil, para evaluar su contribución al aprendizaje exitoso del método. [ABSTRACT FROM AUTHOR]

A brief study about the water-tube steam boiler is carried out in this work, with domes being one of the main components of this equipment. Making use of different codes and standards a theoretical study about the stress and strain in the domes of this kind of boilers is realized; moreover the obtained results by the theoretical methods are proved by means of Finite Elements Analysis (FEA). The stress map is visualized by the simulation of the domes, the stress map is a very important tool because let that the high tension zones are detected as well as to know if the foreseen design guarantee an optimal behavior, in addition the stress map is useful to the maintenance and design personal due to the allowed thickness in the more dangerous zones is knew. [ABSTRACT FROM AUTHOR]

Copyright of DYNA - Ingeniería e Industria is the property of Publicaciones Dyna SL 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.)

Copyright of Revista Tecno Lógicas is the property of Instituto Tecnologico Metropolitano 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.)

Several mathematical models have been used to describe spatial-temporal patterns present in nature such as the skin pigmentation of some fishes and the tiger striped pattern. These mathematical models can be implemented using a wide set of numerical methods among which the finite differences method, the finite elements method and spectral methods are commonly used. In this work, a finite element method is described for the solution of two morphogenesis models, a pattern-formation model and a cell-movement model. The results obtained are similar to those reported by other authors using different numerical approaches. This fact proves the technique to be suitable in the solution of these models and supports our expectations for its use in the solution of complex biological models of growth and cell and tissue development. [ABSTRACT FROM AUTHOR]

The final design of machine finishes after built a prototype and verify that it works correctly. Nevertheless, before building the prototype you can model the equipment in order to detect problems that can arise in the initial proposal. The previous idea was applied in a machine for the production of blocks starting from stabilized soil. The schemes, cinematic and structure of the machine, were made starting from the analysis of similar equipment and of own ideas. A system of oil hydraulic power was included allowing a high force of compression and having a high block productivity with the required quality. Later on, it was determined, in an experimental way, the compression force applied to a stabilized soil, allows blocks to resist an effort to compression settled down by the norm of quality. The dangerous parts of the equipment were modelled in a finite elements program, with the force of defined compression. The results are shown, pointing out that in some elements, the original proposal failed and intending new solutions were made. [ABSTRACT FROM AUTHOR]

We present computational software to analyze the characteristic propagation of light pulses in dielectric waveguides with any cross section. PHOENIXOWA solves the Helmholtz equation by means of the scalar finite dement method, by dividing the cross section of the waveguide in subregions named elements, providing outstanding information of the waveguide propagating modes. It includes a computational tool to consider situations with both thermo-mechanical and light polarization effects. In this work, some characteristics of the software and the error analysis conducted to optimize the computational resources are detailed. [ABSTRACT FROM AUTHOR]

A mathematical model based developed in coordinated polar and a computational procedure for graphic generation of tooth flanks in external parallel-axis cylindrical involute gears are exposed. The mentioned model and procedure are able to consider the effect in the tooth gear geometry of the addendum modification coefficient and the rack shaped tool used in the cutting of gear. Additionally, the results are useful for the improvement of the gear tooth model and formulations for the load capacity calculation of cylindrical gears by means of the method of finite elements. For the determination of the calculation procedures based on the mathematical models was established using the technique of dichromatic graphs. [ABSTRACT FROM AUTHOR]