The document discusses residual stresses that arise during welding due to localized heating and rapid cooling. It analyzes how welding conditions like travel speed, specimen size, constraints, and preheating can affect residual stress distributions. A finite element model is used to simulate butt welding and predict residual stresses in the weld and base metal. The results show that transverse and longitudinal residual stresses are highest near the weld and decrease with increasing distance. Faster travel speeds, larger specimen sizes, and preheating can reduce residual stresses, while external constraints decrease transverse shrinkage and associated stresses.
SIMULATION OF GENERATION OF HIGH PRESSURE AND TEMPERATURE IN METALS UNDER SHO...IJORCS
This document simulates the generation of high pressure and temperature in metals under shock loading. It presents equations to model the total pressure and energy behind a shock front in metals. The pressure is modeled as a function of density ratio and temperature, taking into account cold, thermal, and excitation pressures. Results show that as the shock wave converges towards the center of a spherical metal sample, excitation pressure dominates over elastic and thermal pressures. Graphs show the variation of pressure and temperature in different metals like aluminum, iron, stainless steel, molybdenum, and iridium as the shock wave moves inward. Thermal pressure initially increases then levels off, while excitation pressure rises very fast before decreasing as the shock nears the center
This document summarizes a study on the effects of radiation on magnetohydrodynamic (MHD) free convection flow of a viscous fluid past an exponentially accelerated vertical plate. The governing equations are solved numerically using an implicit finite difference Crank-Nicolson method. It is found that the fluid velocity decreases with increasing magnetic field or radiation parameter. Fluid temperature also decreases with stronger radiation. Shear stress and heat transfer at the plate increase and decrease, respectively, with higher radiation or magnetic parameters.
Effect of rotation on the onset of Rayleigh-Bénard convection in a layer of F...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
11.effect of radiation and chemical reaction on transient mhd free convective...Alexander Decker
This document analyzes the effects of radiation, chemical reaction, and transient magnetohydrodynamic (MHD) free convective flow over a vertical plate through porous media. The governing equations for this unsteady, viscous flow are presented and non-dimensionalized. The equations are then linearized using a perturbation method about a small parameter. Solutions are obtained by reducing the coupled, nonlinear partial differential equations to a set of ordinary differential equations that can be solved analytically. Parameters such as the chemical reaction parameter, thermal Grashof number, and radiation parameter are discussed in relation to their effects on the convective heat transfer along the plate.
Effect of radiation and chemical reaction on transient mhd free convective fl...Alexander Decker
This document analyzes the effects of radiation, chemical reaction, and transient magnetohydrodynamic (MHD) free convective flow over a vertical porous plate. The governing equations for mass, momentum, energy and concentration are presented and solved using perturbation methods. Parameters like chemical reaction rate, thermal and mass Grashof numbers, rarefaction, magnetic field, radiation, and suction are studied. Graphical results are discussed for practical parameter ranges regarding heat and mass transfer over the plate embedded in a porous medium under the influence of thermal radiation and chemical reaction.
Effect of radiation and chemical reaction on transient mhd free convective fl...Alexander Decker
This document analyzes the effects of radiation, chemical reaction, and transient magnetohydrodynamic (MHD) free convective flow over a vertical plate through porous media. The governing equations for mass, momentum, energy and concentration are presented and solved using a perturbation method. Parameters like chemical reaction rate, thermal and mass Grashof numbers, rarefaction, magnetic field, radiation, and suction are studied. Graphical results are discussed for practical parameter ranges regarding heat and mass transfer characteristics of the transient flow.
This document presents a numerical solution for unsteady heat and mass transfer flow past an infinite vertical plate with variable thermal conductivity, taking into account Dufour number and heat source effects. The governing equations are non-linear and coupled, and were solved numerically using an implicit finite difference scheme. Various parameters, including Dufour number and heat source, were found to influence the velocity, temperature, and concentration profiles. Skin friction, Nusselt number, and Sherwood number were also calculated.
SIMULATION OF GENERATION OF HIGH PRESSURE AND TEMPERATURE IN METALS UNDER SHO...IJORCS
This document simulates the generation of high pressure and temperature in metals under shock loading. It presents equations to model the total pressure and energy behind a shock front in metals. The pressure is modeled as a function of density ratio and temperature, taking into account cold, thermal, and excitation pressures. Results show that as the shock wave converges towards the center of a spherical metal sample, excitation pressure dominates over elastic and thermal pressures. Graphs show the variation of pressure and temperature in different metals like aluminum, iron, stainless steel, molybdenum, and iridium as the shock wave moves inward. Thermal pressure initially increases then levels off, while excitation pressure rises very fast before decreasing as the shock nears the center
This document summarizes a study on the effects of radiation on magnetohydrodynamic (MHD) free convection flow of a viscous fluid past an exponentially accelerated vertical plate. The governing equations are solved numerically using an implicit finite difference Crank-Nicolson method. It is found that the fluid velocity decreases with increasing magnetic field or radiation parameter. Fluid temperature also decreases with stronger radiation. Shear stress and heat transfer at the plate increase and decrease, respectively, with higher radiation or magnetic parameters.
Effect of rotation on the onset of Rayleigh-Bénard convection in a layer of F...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Modern Engineering Research (IJMER) covers all the fields of engineering and science: Electrical Engineering, Mechanical Engineering, Civil Engineering, Chemical Engineering, Computer Engineering, Agricultural Engineering, Aerospace Engineering, Thermodynamics, Structural Engineering, Control Engineering, Robotics, Mechatronics, Fluid Mechanics, Nanotechnology, Simulators, Web-based Learning, Remote Laboratories, Engineering Design Methods, Education Research, Students' Satisfaction and Motivation, Global Projects, and Assessment…. And many more.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
11.effect of radiation and chemical reaction on transient mhd free convective...Alexander Decker
This document analyzes the effects of radiation, chemical reaction, and transient magnetohydrodynamic (MHD) free convective flow over a vertical plate through porous media. The governing equations for this unsteady, viscous flow are presented and non-dimensionalized. The equations are then linearized using a perturbation method about a small parameter. Solutions are obtained by reducing the coupled, nonlinear partial differential equations to a set of ordinary differential equations that can be solved analytically. Parameters such as the chemical reaction parameter, thermal Grashof number, and radiation parameter are discussed in relation to their effects on the convective heat transfer along the plate.
Effect of radiation and chemical reaction on transient mhd free convective fl...Alexander Decker
This document analyzes the effects of radiation, chemical reaction, and transient magnetohydrodynamic (MHD) free convective flow over a vertical porous plate. The governing equations for mass, momentum, energy and concentration are presented and solved using perturbation methods. Parameters like chemical reaction rate, thermal and mass Grashof numbers, rarefaction, magnetic field, radiation, and suction are studied. Graphical results are discussed for practical parameter ranges regarding heat and mass transfer over the plate embedded in a porous medium under the influence of thermal radiation and chemical reaction.
Effect of radiation and chemical reaction on transient mhd free convective fl...Alexander Decker
This document analyzes the effects of radiation, chemical reaction, and transient magnetohydrodynamic (MHD) free convective flow over a vertical plate through porous media. The governing equations for mass, momentum, energy and concentration are presented and solved using a perturbation method. Parameters like chemical reaction rate, thermal and mass Grashof numbers, rarefaction, magnetic field, radiation, and suction are studied. Graphical results are discussed for practical parameter ranges regarding heat and mass transfer characteristics of the transient flow.
This document presents a numerical solution for unsteady heat and mass transfer flow past an infinite vertical plate with variable thermal conductivity, taking into account Dufour number and heat source effects. The governing equations are non-linear and coupled, and were solved numerically using an implicit finite difference scheme. Various parameters, including Dufour number and heat source, were found to influence the velocity, temperature, and concentration profiles. Skin friction, Nusselt number, and Sherwood number were also calculated.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document analyzes mixed convection MHD flow of nanofluid over a non-linear stretching sheet with thermal radiation, viscous dissipation, variable magnetic field, and suction. It presents governing equations and solves them using similarity transformations to obtain velocity and temperature profiles. Results show that increasing the magnetic field, Prandtl number, local Grashof number, Eckert number, and nanoparticle volume fraction affects the velocity and thermal fields. Thermal boundary layer equations account for viscous and Ohmic dissipation. Solutions indicate increasing magnetic field and suction decreases velocity and temperature profiles for the stretching sheet.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Nanofluid Flow past an Unsteady Permeable Shrinking Sheet with Heat Source or...IJERA Editor
The consideration of nanofluids has been paid a good attention on the forced convection; the analysis focusing
nanofluids in porous media are limited in literature. Thus, the use of nanofluids in porous media would be very
much helpful in heat and mass transfer enhancement. In this paper, the influence of variable suction, Newtonian
heating and heat source or sink heat and mass transfer over a permeable shrinking sheet embedded in a porous
medium filled with a nanofluid is discussed in detail. The solutions of the nonlinear equations governing the
velocɨty, temperature and concentration profiles are solved numerically using Runge-Kutta Gill procedure
together with shooting method and graphical results for the resulting parameters are displayed and discussed.
The influence of the physical parameters on skin-friction coefficient, local Nusselt number and local Sherwood
number are shown in a tabulated form.
Effects Of Heat Source And Thermal Diffusion On An Unsteady Free Convection F...IOSR Journals
This document presents a mathematical analysis of unsteady free convection flow along a porous vertical plate with constant heat and mass flux in a rotating system. The analysis considers the effects of heat source and thermal diffusion. Perturbation technique is used to obtain expressions for velocity, temperature, concentration profiles, skin friction, and Nusselt number. Key findings include that increasing Schmidt number decreases skin friction, increasing Grashoff number increases skin friction, and increasing Prandtl number decreases Nusselt number. Graphs and tables are used to discuss the effects of various parameters on flow variables.
The present study analyzes the steady boundary layer slip flow of magneto-nanofluid due to an exponentially permeable stretching sheet with heat generation/absorption. In this paper, the effects of Brownian motion and thermophoresis on heat transfer and nanoparticle volume friction are considered. Using shooting technique along with fourth-order Runge-Kutta method the transformed equations are solved. The study reveals that the governing parameters, namely, the magnetic parameter, wall mass suction parameter, Prandtl number, the Lewis number, slip parameter, heat generation/absorption parameter, Brownian motion parameter, and thermophoresis parameter, have major effects on the flow field, the heat transfer, and the nanoparticle volume fraction as well as skin friction, local Nusselt number and local Sherwood number has been discussed in detail.
This document summarizes research on thermohaline convection in porous media. Specifically, it presents:
1) An analysis of thermohaline convection using the Brinkman model, which accounts for non-Darcy effects important at high permeability.
2) Derivation of the linearized perturbation equations governing small disturbances to the initial steady state.
3) Non-dimensionalization of the governing equations and introduction of relevant non-dimensional parameters.
4) The resulting non-dimensional equations are to be solved subject to specified boundary conditions, in order to characterize oscillatory motions in thermohaline configurations of Veronis and Stern types within porous media.
Convective Heat And Mass Transfer Flow Of A Micropolar Fluid In A Rectangular...IJERA Editor
In this chapter we make an investigation of the convective heat transfer through a porous medium in a Rectangular enclosure with Darcy model. The transport equations of liner momentum, angular momentum and energy are solved by employing Galerkine finite element analysis with linear triangular elements. The computation is carried out for different values of Rayleigh number – Ra micropolar parameter – R, spin gradient parameter, Eckert number Ec and heat source parameter. The rate of heat transfer and couple stress on the side wall is evaluated for different variation of the governing parameters.
Radiation and magneticfield effects on unsteady naturalAlexander Decker
This document discusses research on the effects of thermal radiation and magnetic fields on unsteady natural convective flow of nanofluids past an infinite vertical plate with a heat source. The following key points are discussed:
- Governing equations for the unsteady, two-dimensional flow are derived taking into account radiation, magnetic fields, and thermophysical properties of nanofluids.
- The equations are solved numerically using Laplace transform techniques. Parameters like radiation, magnetic field, heat source, and nanoparticle volume fraction are examined.
- It is found that increasing the magnetic field decreases fluid velocity, while radiation, heat source, and nanoparticle volume fraction have a greater influence on fluid velocity and temperature profiles. Nan
Nonlinear Asymmetric Kelvin-Helmholtz Instability Of Cylindrical Flow With Ma...ijtsrd
The nonlinear asymmetric Kelvin-Helmholtz stability of the cylindrical interface between the vapor and liquid phases of a °uid is studied when the phases are enclosed between two cylindri- cal surfaces coaxial with the interface, and when there is mass and heat transfer across the inter- face. The method of multiple time expansion is used for the investigation. The evolution of am- plitude is shown to be governed by a nonlinear ¯rst order di®erential equation. The stability cri- terion is discussed, and the region of stability is displayed graphically. Also investigated in this paper is the viscous linear potential °ow. DOO-SUNG LEE"Nonlinear Asymmetric Kelvin-Helmholtz Instability Of Cylindrical Flow With Mass And Heat Transfer And The Viscous Linear Analysis" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-5 , August 2018, URL: http://www.ijtsrd.com/papers/ijtsrd17030.pdf http://www.ijtsrd.com/mathemetics/applied-mathematics/17030/nonlinear-asymmetric-kelvin-helmholtz-instability-of-cylindrical-flow-with-mass-and-heat-transfer-and-the-viscous-linear-analysis/doo-sung-lee
This document summarizes a study on magnetohydrodynamic (MHD) boundary layer flow over a moving vertical plate in a porous medium. The study analyzes the effects of suction and viscous dissipation on heat and mass transfer. The governing equations are reduced to a nonlinear boundary value problem using similarity transformations and solved numerically. Results show that fluid velocity decreases with increasing magnetic parameter and increases with increasing thermal or solutal Grashof numbers, representing the effects of buoyancy forces.
This document presents a simple phenomenological approach to modeling nanoindentation creep using conventional spring and dashpot elements. It describes how creep, which is the time-dependent increase in depth under a held load, can be modeled for a variety of materials using Maxwell and Voigt models. Equations are presented that relate the depth increase over time to the elastic modulus and viscosity of the material being tested. A method is described for fitting experimental nanoindentation data, including holding periods, to these equations to determine material properties while accounting for creep. The approach aims to provide an accessible way to analyze creep in nanoindentation that can be incorporated into computer programs.
The document presents an analytical solution for unsteady flow past an accelerated vertical plate with variable temperature and mass transfer. The governing equations for momentum, energy, and mass transfer are non-dimensionalized and solved using the Laplace transform technique. Solutions are obtained for velocity, temperature, and concentration in terms of exponential and error functions. The results show that velocity increases with increasing Schmidt number, time, thermal Grashof number, and mass Grashof number, while temperature increases with time but decreases with increasing Prandtl number. Concentration is found to increase with time and decrease with increasing Schmidt number.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
ASPHALTIC MATERIAL IN THE CONTEXT OF GENERALIZED POROTHERMOELASTICITYijsc
This document summarizes a mathematical model of generalized porothermoelasticity for a porous asphalt material. The model considers a poroelastic half-space saturated with fluid and constructs governing equations for the stresses, strains, displacements, and temperatures of the solid and fluid phases. The equations are derived using the theory of generalized porothermoelasticity with one relaxation time. Numerical solutions to the equations are obtained by applying the model to an asphalt material subjected to thermal shock on its surface. Graphs of the temperature, stresses, strains, and displacements within the material are presented.
Thermal Modeling of Electron Beam Additive Manufacturing Process–Powder Sinte...Ninggang Shen
This document summarizes research on modeling the thermal effects of the electron beam additive manufacturing process, specifically how powder sintering affects temperature distribution and melt pool geometry. Key findings from simulations include higher temperatures and deeper melt pools with increasing powder porosity. Larger beam sizes produced shallower melt pools. Future work is proposed on modeling overhang structures, thermal effects at solid/powder interfaces, and thermo-mechanical analysis.
Simulations of Thermo-Mechanical Characteristics in Electron Beam Additive Ma...Ninggang Shen
This document summarizes simulations of the thermo-mechanical characteristics of electron beam additive manufacturing (EBAM). A 3D finite element model was developed to investigate thermal response, residual stress, and deformation. The model considers conical heat flux, Gaussian intensity distribution, and linear heat decay. Temperature, stress, and deformation results are presented from simulations of single-line scans and multi-layer crossed raster patterns. Peak tensile stresses occur at the solidification front, and maximum deformation follows the beam path. Future work will focus on simulating hatch melting patterns.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Este documento describe los diferentes estados de la materia y los cambios entre ellos. Explica que un sistema se define por la posición y velocidad de sus masas puntuales y describe los estados sólido, líquido y gaseoso. Además, define los procesos de fusión, solidificación, vaporización, licuación, sublimación, cristalización, ionización y deionización, que son los cambios entre los diferentes estados.
O documento descreve o clima, vegetação e fauna do Pantanal brasileiro. O clima é quente e úmido no verão e seco no inverno, com chuvas concentradas entre outubro e março. A vegetação inclui plantas aquáticas como vitória-régia e samambaia e animais como ariranha, macacos e diversas espécies de peixes como piranha e dourado.
La CPU es el conjunto de la unidad de control y la unidad aritmetica. La tarjeta de video transmite la informacion grafica del procesador al monitor. La tarjeta de sonido permite reproducir y grabar sonido. Las tarjetas de red y expansion permiten conectar más dispositivos al computador. La memoria almacena la informacion que usa el procesador. El disco duro almacena programas y archivos de forma permanente.
El documento discute las diferencias entre países pobres y ricos. Indica que factores como la edad del país, los recursos naturales y la raza no determinan si un país es rico o pobre. En cambio, la principal diferencia radica en el nivel de conciencia y los valores de la población. Los países ricos tienden a adoptar valores como la ética, la integridad y el respeto por la ley, mientras que la educación y la cultura deben enfocarse en promover valores morales y espirituales para transformar la conciencia de la gente a
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document analyzes mixed convection MHD flow of nanofluid over a non-linear stretching sheet with thermal radiation, viscous dissipation, variable magnetic field, and suction. It presents governing equations and solves them using similarity transformations to obtain velocity and temperature profiles. Results show that increasing the magnetic field, Prandtl number, local Grashof number, Eckert number, and nanoparticle volume fraction affects the velocity and thermal fields. Thermal boundary layer equations account for viscous and Ohmic dissipation. Solutions indicate increasing magnetic field and suction decreases velocity and temperature profiles for the stretching sheet.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Nanofluid Flow past an Unsteady Permeable Shrinking Sheet with Heat Source or...IJERA Editor
The consideration of nanofluids has been paid a good attention on the forced convection; the analysis focusing
nanofluids in porous media are limited in literature. Thus, the use of nanofluids in porous media would be very
much helpful in heat and mass transfer enhancement. In this paper, the influence of variable suction, Newtonian
heating and heat source or sink heat and mass transfer over a permeable shrinking sheet embedded in a porous
medium filled with a nanofluid is discussed in detail. The solutions of the nonlinear equations governing the
velocɨty, temperature and concentration profiles are solved numerically using Runge-Kutta Gill procedure
together with shooting method and graphical results for the resulting parameters are displayed and discussed.
The influence of the physical parameters on skin-friction coefficient, local Nusselt number and local Sherwood
number are shown in a tabulated form.
Effects Of Heat Source And Thermal Diffusion On An Unsteady Free Convection F...IOSR Journals
This document presents a mathematical analysis of unsteady free convection flow along a porous vertical plate with constant heat and mass flux in a rotating system. The analysis considers the effects of heat source and thermal diffusion. Perturbation technique is used to obtain expressions for velocity, temperature, concentration profiles, skin friction, and Nusselt number. Key findings include that increasing Schmidt number decreases skin friction, increasing Grashoff number increases skin friction, and increasing Prandtl number decreases Nusselt number. Graphs and tables are used to discuss the effects of various parameters on flow variables.
The present study analyzes the steady boundary layer slip flow of magneto-nanofluid due to an exponentially permeable stretching sheet with heat generation/absorption. In this paper, the effects of Brownian motion and thermophoresis on heat transfer and nanoparticle volume friction are considered. Using shooting technique along with fourth-order Runge-Kutta method the transformed equations are solved. The study reveals that the governing parameters, namely, the magnetic parameter, wall mass suction parameter, Prandtl number, the Lewis number, slip parameter, heat generation/absorption parameter, Brownian motion parameter, and thermophoresis parameter, have major effects on the flow field, the heat transfer, and the nanoparticle volume fraction as well as skin friction, local Nusselt number and local Sherwood number has been discussed in detail.
This document summarizes research on thermohaline convection in porous media. Specifically, it presents:
1) An analysis of thermohaline convection using the Brinkman model, which accounts for non-Darcy effects important at high permeability.
2) Derivation of the linearized perturbation equations governing small disturbances to the initial steady state.
3) Non-dimensionalization of the governing equations and introduction of relevant non-dimensional parameters.
4) The resulting non-dimensional equations are to be solved subject to specified boundary conditions, in order to characterize oscillatory motions in thermohaline configurations of Veronis and Stern types within porous media.
Convective Heat And Mass Transfer Flow Of A Micropolar Fluid In A Rectangular...IJERA Editor
In this chapter we make an investigation of the convective heat transfer through a porous medium in a Rectangular enclosure with Darcy model. The transport equations of liner momentum, angular momentum and energy are solved by employing Galerkine finite element analysis with linear triangular elements. The computation is carried out for different values of Rayleigh number – Ra micropolar parameter – R, spin gradient parameter, Eckert number Ec and heat source parameter. The rate of heat transfer and couple stress on the side wall is evaluated for different variation of the governing parameters.
Radiation and magneticfield effects on unsteady naturalAlexander Decker
This document discusses research on the effects of thermal radiation and magnetic fields on unsteady natural convective flow of nanofluids past an infinite vertical plate with a heat source. The following key points are discussed:
- Governing equations for the unsteady, two-dimensional flow are derived taking into account radiation, magnetic fields, and thermophysical properties of nanofluids.
- The equations are solved numerically using Laplace transform techniques. Parameters like radiation, magnetic field, heat source, and nanoparticle volume fraction are examined.
- It is found that increasing the magnetic field decreases fluid velocity, while radiation, heat source, and nanoparticle volume fraction have a greater influence on fluid velocity and temperature profiles. Nan
Nonlinear Asymmetric Kelvin-Helmholtz Instability Of Cylindrical Flow With Ma...ijtsrd
The nonlinear asymmetric Kelvin-Helmholtz stability of the cylindrical interface between the vapor and liquid phases of a °uid is studied when the phases are enclosed between two cylindri- cal surfaces coaxial with the interface, and when there is mass and heat transfer across the inter- face. The method of multiple time expansion is used for the investigation. The evolution of am- plitude is shown to be governed by a nonlinear ¯rst order di®erential equation. The stability cri- terion is discussed, and the region of stability is displayed graphically. Also investigated in this paper is the viscous linear potential °ow. DOO-SUNG LEE"Nonlinear Asymmetric Kelvin-Helmholtz Instability Of Cylindrical Flow With Mass And Heat Transfer And The Viscous Linear Analysis" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-5 , August 2018, URL: http://www.ijtsrd.com/papers/ijtsrd17030.pdf http://www.ijtsrd.com/mathemetics/applied-mathematics/17030/nonlinear-asymmetric-kelvin-helmholtz-instability-of-cylindrical-flow-with-mass-and-heat-transfer-and-the-viscous-linear-analysis/doo-sung-lee
This document summarizes a study on magnetohydrodynamic (MHD) boundary layer flow over a moving vertical plate in a porous medium. The study analyzes the effects of suction and viscous dissipation on heat and mass transfer. The governing equations are reduced to a nonlinear boundary value problem using similarity transformations and solved numerically. Results show that fluid velocity decreases with increasing magnetic parameter and increases with increasing thermal or solutal Grashof numbers, representing the effects of buoyancy forces.
This document presents a simple phenomenological approach to modeling nanoindentation creep using conventional spring and dashpot elements. It describes how creep, which is the time-dependent increase in depth under a held load, can be modeled for a variety of materials using Maxwell and Voigt models. Equations are presented that relate the depth increase over time to the elastic modulus and viscosity of the material being tested. A method is described for fitting experimental nanoindentation data, including holding periods, to these equations to determine material properties while accounting for creep. The approach aims to provide an accessible way to analyze creep in nanoindentation that can be incorporated into computer programs.
The document presents an analytical solution for unsteady flow past an accelerated vertical plate with variable temperature and mass transfer. The governing equations for momentum, energy, and mass transfer are non-dimensionalized and solved using the Laplace transform technique. Solutions are obtained for velocity, temperature, and concentration in terms of exponential and error functions. The results show that velocity increases with increasing Schmidt number, time, thermal Grashof number, and mass Grashof number, while temperature increases with time but decreases with increasing Prandtl number. Concentration is found to increase with time and decrease with increasing Schmidt number.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
ASPHALTIC MATERIAL IN THE CONTEXT OF GENERALIZED POROTHERMOELASTICITYijsc
This document summarizes a mathematical model of generalized porothermoelasticity for a porous asphalt material. The model considers a poroelastic half-space saturated with fluid and constructs governing equations for the stresses, strains, displacements, and temperatures of the solid and fluid phases. The equations are derived using the theory of generalized porothermoelasticity with one relaxation time. Numerical solutions to the equations are obtained by applying the model to an asphalt material subjected to thermal shock on its surface. Graphs of the temperature, stresses, strains, and displacements within the material are presented.
Thermal Modeling of Electron Beam Additive Manufacturing Process–Powder Sinte...Ninggang Shen
This document summarizes research on modeling the thermal effects of the electron beam additive manufacturing process, specifically how powder sintering affects temperature distribution and melt pool geometry. Key findings from simulations include higher temperatures and deeper melt pools with increasing powder porosity. Larger beam sizes produced shallower melt pools. Future work is proposed on modeling overhang structures, thermal effects at solid/powder interfaces, and thermo-mechanical analysis.
Simulations of Thermo-Mechanical Characteristics in Electron Beam Additive Ma...Ninggang Shen
This document summarizes simulations of the thermo-mechanical characteristics of electron beam additive manufacturing (EBAM). A 3D finite element model was developed to investigate thermal response, residual stress, and deformation. The model considers conical heat flux, Gaussian intensity distribution, and linear heat decay. Temperature, stress, and deformation results are presented from simulations of single-line scans and multi-layer crossed raster patterns. Peak tensile stresses occur at the solidification front, and maximum deformation follows the beam path. Future work will focus on simulating hatch melting patterns.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Este documento describe los diferentes estados de la materia y los cambios entre ellos. Explica que un sistema se define por la posición y velocidad de sus masas puntuales y describe los estados sólido, líquido y gaseoso. Además, define los procesos de fusión, solidificación, vaporización, licuación, sublimación, cristalización, ionización y deionización, que son los cambios entre los diferentes estados.
O documento descreve o clima, vegetação e fauna do Pantanal brasileiro. O clima é quente e úmido no verão e seco no inverno, com chuvas concentradas entre outubro e março. A vegetação inclui plantas aquáticas como vitória-régia e samambaia e animais como ariranha, macacos e diversas espécies de peixes como piranha e dourado.
La CPU es el conjunto de la unidad de control y la unidad aritmetica. La tarjeta de video transmite la informacion grafica del procesador al monitor. La tarjeta de sonido permite reproducir y grabar sonido. Las tarjetas de red y expansion permiten conectar más dispositivos al computador. La memoria almacena la informacion que usa el procesador. El disco duro almacena programas y archivos de forma permanente.
El documento discute las diferencias entre países pobres y ricos. Indica que factores como la edad del país, los recursos naturales y la raza no determinan si un país es rico o pobre. En cambio, la principal diferencia radica en el nivel de conciencia y los valores de la población. Los países ricos tienden a adoptar valores como la ética, la integridad y el respeto por la ley, mientras que la educación y la cultura deben enfocarse en promover valores morales y espirituales para transformar la conciencia de la gente a
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1. S.R. Thorat , Dr.Y. R. Kharde, K.C. Bhosale, S.B. Kharde / International Journal of
Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 1, January -February 2013, pp.1434-1439
Effect Of Welding Conditions On Residual Stresses And Heat
Source Distribution On Temperature Variations On Butt
Welds : A Review
S.R. Thorat* , Dr.Y.R.Kharde**, K.C. Bhosale ***, S.B. Kharde****
*Asst. Professor ,Department of Mechanical Engineering , College of Engineering , Kopargaon , India
**Principal , College of Engineering , Rahata , India
*** & ****Asst. Professor , Department of Mechanical Engineering , College of Engineering , Kopargaon ,
India
ABSTRACT
Fusion welding is a joining process in between the parent metals. The heat source causes
which the coalescence of metals is accomplished highly non-uniform temperature distributions across
by fusion. Owing to localized heating by the the joint and the parent metals.Therefore, the
welding process and subsequent rapid cooling, thermal expansion and contraction during heating
residual stresses can arise in the weld itself and in and subsequently cooling as well as material plastic
the base metal. Residual stresses attributed to deformation at elevated temperatures result in
welding pose significant problems in the accurate inevitable distortions and residual stresses in the
fabrication of structures because those stresses joint and the parent metals, which greatly affects the
heavily induce brittle fracturing and degrade the fabrication tolerance and quality.[5]
buckling strength of welded structures. Residual stresses during welding are
Therefore, estimating the magnitude and unavoidable and their effects on welded structures
distribution of welding residual stresses and cannot be disregarded. Design and fabrication
characterizing the effects of certain welding conditions, such as the structure thickness, joint
conditions on the residual stresses are deemed design, welding conditions and welding sequence,
necessary. The transient temperature must be altered so that the adverse effects of
distributions and temperature variations of the residual stresses can be reduced to acceptable levels.
welded plates during welding were predicted and In this work, we predict the residual stresses during
the fusion zone and heat affected zone were one-pass arc welding in a steel plate using ansys
obtained. finite element techniques. The effects of travel
speed, specimen size, external mechanical
Keyword: residual stresses , transient temperature constraints and preheat on residual stresses are also
history . discussed. [6]
1.INTRODUCTION 2.SIMULATION OF PLATE BUT JOINT
Fusion welding is a joining process in WELDING
which the coalescence of metals is achieved by Welding residual stress distribution is
fusion. This form of welding has been widely calculated by ansys finite element techniques.
employed in fabricating structures such as ships, Theoretical considerations can be assessed either by
offshore structures, steel bridges, and pressure a thermal or a mechanical model.
vessels. Owing to localized heating by the welding
process and subsequent rapid cooling, residual 2.1. Governing equations
stresses can arise in the weld itself and in the base When a volume is bounded by an arbitrary
metal. Such stresses are usually of yield point surface S, the balance relation of the heat flow is
magnitude. Residual stresses attributed to welding expressed by
pose significant problems in the accurate fabrication
of structures because those stresses heavily induce R R R
brittle fracturing and degrade the buckling strength X Y z Q x, y , z , t
of welded structures. x y z
Therefore, estimating the magnitude and T ( x, y, z, t )
distribution of welding residual stresses and C (1)
characterizing the effects of certain welding t
conditions on the residual stresses are relevant tasks.
A metal inert gas (MIG) welding process
Where RX , RY , Rz are the rates of heat flow per
consists of heating, melting and solidification of
parent metals and a filler material in localized fusion unit area , T x, y, z, t is current temperature,
zone by a transient heat source to form a joint
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2. S.R. Thorat , Dr.Y. R. Kharde, K.C. Bhosale, S.B. Kharde / International Journal of
Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 1, January -February 2013, pp.1434-1439
Q x, y, z, t is rate of internal heat generation , is 2.2 Material properties
Since welding processes undergo a high
density , C is specific heat and t is time . temperature cycle and exhibit material properties
The model can be completed by introducing the that are temperaturedependant, the transient
fourier heat flow as temperature can be calculated by an extrapolation
T method with a two-time interval as
RX kx (2a)
x
T
T ( ) T (t t ) T (t t ) T (t 2t ) (7)
t
RY k y (2b)
y
Let g denote the temperature-dependent material
T
Rz k z (2c) coefficient, i.e. the function of T ( ) . The material
z
coefficient at time t can be expressed as
Where k x , k y , k z are the thermal conductivities in t
1
the x,y,z directions respectively . g g T ( )d
t t t
(8)
By considering that the process in the material non-
Fig.1.Geometry of butt-welded plates
linear,the parameters k x , k y , k z , , C are
function of temperature .
Inserting eqns (2a),(2b),(2c) into eqn (1) yields
T T T
ky Q
x x y y z z
kx kz
T
C
t
(3)
Eqn (3) is the differential equation
governing heat conduction in a solid body .The
general solution is obtained by accepting the initial
and boundry conditions .
initial condition
T x, y, z, 0 T0 x, y, z (4)
Boundry condition
T T T
kx Nx ky N y kz Nz
x x y y z z
qs hc (T T ) hr (T Tr ) 0
(5)
Where N x , N y , N z are direction cosines 2.3 Mechanical model analysis
Two basic sets of equations relating to the
of the outward drawn normal to boundry , hc is mechanical model, the equilibrium equations and
convection heat transfer coefficient, hr is radiation the constitutive equations, are considered as follows.
(a) Equations of equilibrium
heat transfer coefficient , q s is boundry heat flux ij , j bi 0 (9a)
, T is surrounding temperature , Tr is temperature And
of radiation heat source. ij ji (9b)
The radiation heat transfer coefficient is expressed
as where ij is the stress tensor and bi is the body
force.
hr F (T 2 Tr 2 )(T Tr ) (6) (b) Constitutive equations for a thermal elasto-
plastic material.
In which is Stefan –Boltzmzn constant The thermal elasto-plastic material model,
, is effective emissivity and F is configuration based on the von Mises yield criterion and the
factor. isotropic strain hardening rule, is considered.
Stress–strain relations can be written as
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Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 1, January -February 2013, pp.1434-1439
d Dep d C th dT
(10) in regions removed from the weld. The maximum
stress value is as high as the material’s yield stress.
And
D ep D e D p
(11) Fig.3.The longitudinal stress along X direction
Where D elastic stiffness matrix , D is
e
p
plastic stiffness matrix , C is thermal stiffness
th
matrix , d is strain increment and dT is the
temperature increment.[6]
3. ESTIMATION OF WELDING
RESIDUAL STRESSES
3.1.Analyzed model
A stress acting normal to the direction of
the weld bead, is known as a transverse stress,
denoted by the term x .Fig.4 illustrates the
distributions of transverse residual stress x along
the y direction. at the middle of the plate, and the
compressive stresses occur at the ends of the weld.
Fig.2 Mechanical properties of welded plates
Fig. 1 depicts the specimen in this study.
Analysis is performed on two long plates of 300 mm
length and 100 mm width by butt welding. The
magnitude of heat input is characterized by a
welding current I . 110 A, voltage V . 20 V, welding
speed v . 5 mm/s and the efficiency of heat-input Eff
. 0.7. Fig.2 displays the material’s thermal and
mechanical properties.
Evaluating the three-dimensional residual
stresses may require a considerable amount of
computational time and cost. Herein, a two-
dimensional axisymmetric model was designed to
calculate the residual stress of the plate by the ansys
finite element code. Four-node thermalstructure
couple elements were also used .
Fig.4.The transerverse stress along y direction
3.2. Results and discussion
A stress acting parallel to the direction of 4. THE EFFECT OF WELDING
the weld bead is known as a longitudinal stress, CONDITIONS CONDITIONS ON
denoted by the term x . Fig. 3 depicts the RESIDUAL STRESSES
distributions of longitudinal residual stress along the In welded structures, reducing the residual
x direction. High tensile stresses occur in regions stresses during an early stage of design and
near the weld due to a resistance contraction of the fabrication is of priority concern. For this reason,
material as cooling commences. Also, for self- the effects of certain welding conditions on the
equilibrating purposes, compressive stresses occur residual stresses are characterized in the following.
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Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 1, January -February 2013, pp.1434-1439
4.1. Effects of specimen length Fig.6.effect of specimen thickness on Longitudinal
A butt-welded plate joint of thin plate is residual stresses
considered as a model for analysis under the
welding conditions mentioned earlier. The The tensile stress always appears only in
specimen’s width is assumed to be 200 mm, and the the areas near the fusion zone. The fact that the
length of specimen varies as 50 mm, 100 mm, 200 absorption energy per unit volume in a thin
mm and 400 mm. Fig. 5 summarizes the effect of weldment exceeds that in thick ones accounts for
specimen length on transverse residual stresses. This why the residual stresses increased with decreasing
figure indicates that the transverse residual stresses specimen thickness .
are tensile in the central areas and compressive in
the areas near the plate ends. Notably, the high 4.3 Effects of travel speed
tensile stresses in the central region decrease with Approximately the same weld size was
increasing length of the specimen. produced with various travel speeds of 3.33 mm/s, 7
mm/s and 10 mm/s. A higher welding speed not
4.2. Effects of specimen thickness only reduces the amount of adjacent material
Welds were made with some heat input. affected by the heat of the arc, but also
Fig. 6 presents the distributions of longitudinal progressively decreases the residual stresses, as
residual stresses at the top surface with various shown in Fig. 7.
specimen thicknesses, i.e. 5 mm, 8 mm, 12 mm, in The important difference lies in the fact
the weld metal of a butt joint. that the higher speed welding technique produced a
slightly narrower isotherm. This isotherm’s width
influences the transverse shrinkage of butt welds,
accounting for why faster welding speeds generally
result in less residual stresses.
Fig.5. The effect of specimen length on
transerverse residual stresses
Fig.7. The effect of travel speed on transerverse
residual stresses
4.4. Effects of external mechanical constraints
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Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 1, January -February 2013, pp.1434-1439
The thermal and mechanical behavior of transverse residual stresses significantly reduce after
weldments could be readily manipulated through applying the preheating treatment.
external constraints. For a circumstance in which the
lateral contraction of the joint is restrained by an
external constraint, Fig. 8 depicts the distribution of
transverse residual stresses. Moreover, the fact that
the degree of the transverse shrinkage of a restrained
joint is reduced accounts for why the magnitude of
the residual stresses with a restrained joint is larger
than that estimated with an unrestrained joint.
Fig.9.The effect of preheating on
transerverse residual stresses
4.6. Effects of heat source parameters on
temperature
Variations of the heat source distribution
and magnitude affect the shape and boundaries of
FZ and HAZ . The fusion zone has been decreased
when the parameters have been increased,
representing lower values of peak heat fluxes
applied on the plate. It also causes obvious changes
of peak temperatures in FZ and has a noticeable
effect on temperature distributions in the areas close
to HAZ (Fig. 10). The temperature decreases are
non-linear with the increase of the heat source
Fig.8.The effect of mechanical constraint on parameters of a, b, cf and cr. There is a greater
transerverse residual stresses temperature change when a = b = cf are increased
from 5 to 6mmthan that they are increased from 4 to
5 mm. It shows that peak temperatures and
4.5. Effects of preheating temperature distributionsare sensitive to small
The residual stresses depend on the final changes of heat source distributions.[5,6]
equilibrium temperature of the temperature–stress
cycle.Preheating treatments are used primarily to
influence the time at temperature and cooling rates
within the weldment, thereby reducing the residual
stresses. Herein, the specimen was preheated
homogeneously up to 2000C, 3000 C and 4000 C.
Fig. 9 summarizes those results and shows that
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6. S.R. Thorat , Dr.Y. R. Kharde, K.C. Bhosale, S.B. Kharde / International Journal of
Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 3, Issue 1, January -February 2013, pp.1434-1439
5. The magnitude of the residual stresses with a
restrained joint is larger than that estimated
with an unrestrained joint.
6. Owing to the preheating treatment, the
weldment significantly reduces the residual
stresses .
REFFERENCES
1. D. Rosenthal, Mathematical theory of heat
distribution during welding and cutting,
Welding J. 20 (5) (1941) 220–234.
2. G.H. Little, A.G. Kamtekar, The effect of
thermal properties and welding efficiency
on transient temperatures during welding,
Comput. Struct. 68 (1998) 157–165.
3. Norton JH, Rosenthal D. Stress
measurement by X-ray diffraction.
Proceedings of the Society for
Experimental Stress Analysis
1944;1(2):73–76.
4. Shim Y, Feng Z, Lee S, Kim D, Jaeger J,
Papritan JC, Tsai CL.Determination of
residual stresses in thick-section
weldments. Welding Journal
1992;September:305–312.
5. D. Gery , H. Long,P. Maropoulos , Effects
of welding speed, energy input and heat
source distribution on temperature
variations in butt joint welding, Journal of
Materials Processing Technology 167
(2005) ,393–401 .
6. Tso-Liang Teng , Chih-Cheng Lin, Effect
of welding conditions on residual stresses
due to butt welds , International Journal of
Pressure Vessels and Piping 75 (1998),
857–864.
Fig. 10. Effects of heat source parameters on
temperature: (a) along transverse direction and
(b) along longitudinal direction.
5. CONCLUSIONS
1. For the residual stresses distribution in a butt
weld, the middle weld bead is in tension and
the magnitude of this stress equals the yield
stress. The ends of the weld are in
compression.
2. The peak transverse residual stresses in the
central region decrease with an increasing
specimen length.
3. The tensile residual stresses in the region near
the fusion zone increase with a decreasing
specimen thickness.
4. A higher welding speed reduces the amount
ofadjacent material affected by the heat of the
arc and progressively decreases the residual
stresses.
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