An Efficient 2-D Finite Element Procedure for Isothermal Phase Changes

1990 ◽  
Vol 112 (4) ◽  
pp. 352-360 ◽  
Author(s):  
S. Chandrasekar ◽  
S. Wang ◽  
H. T. Y. Yang
Keyword(s):  
Finite Element ◽  
Phase Transformation ◽  
Material Properties ◽  
Thermal Stresses ◽  
Phase Changes ◽  
Transient Temperature ◽  
Two Dimensional ◽  
Transient Temperature Distribution ◽  
Finite Element Procedure ◽  
Transformation Problems

An efficient finite element procedure is developed for the temperature and stress analyses of two-dimensional isothermal phase transformation problems such as solidification, melting, and solid-to-solid transformations, etc. This procedure uses adaptive remeshing along the element boundaries to track the discontinuities in the temperature gradient, the enthalpy, and the material properties, which exists across the phase transformation interface. The thermal stresses and the transient temperature distribution developed during solidification are calculated using this for several example problems. They are compared with the numerical and analytical solutions obtained for these problems by earlier investigators in order to demonstrate the efficiency and accuracy of this method, for the analysis of solidification problems, as well as its limitations.

Analysis of Thermal Stresses and Metal Movement During Welding—Part I: Analytical Study

1975 ◽  
Vol 97 (1) ◽  
pp. 81-84 ◽  
Author(s):  
T. Muraki ◽  
J. J. Bryan ◽  
K. Masubuchi
Keyword(s):  
Finite Element ◽  
Variational Principle ◽  
Material Properties ◽  
Analytical Study ◽  
Thermal Stresses ◽  
Yield Criterion ◽  
Element Formulation ◽  
Two Dimensional ◽  
Butt Welding ◽  
Welding Part

This is the first part of a study of thermal stresses and metal movement during welding. This part discusses analysis of two-dimensional thermal stresses and metal movement during bead-on-plate and butt welding. A finite-element formulation has been derived, based on the variational principle. The formulation includes temperature dependence of material properties as well as the yield criterion.

scholarly journals Phase transformation in two-dimensional covalent organic frameworks under compressive loading

2018 ◽  
Vol 20 (46) ◽  
pp. 29462-29471 ◽  
Author(s):  
Jin Zhang
Keyword(s):  
Phase Transformation ◽  
Material Properties ◽  
Compressive Loading ◽  
Two Dimensional ◽  
Covalent Organic Frameworks

We report a novel phase transformation in 2D COFs under compression, which greatly alters the material properties of 2D COFs.

scholarly journals Probability Study on the Thermal Stress Distribution in Thick HK40 Stainless Steel Pipe Using Finite Element Method

Designs ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 9
Author(s):  
Sujith Bobba ◽  
Shaik Abrar ◽  
Shaik Mujeebur Rehman
Keyword(s):  
Finite Element ◽  
Stainless Steel ◽  
High Temperature ◽  
Material Properties ◽  
Thermal Stresses ◽  
Steel Pipe ◽  
Stress Distributions ◽  
Stainless Steel Pipe ◽  
Deterministic Solution ◽  
Analytical Expressions

The present work deals with the development of a finite element methodology for obtaining the stress distributions in thick cylindrical HK40 stainless steel pipe that carries high-temperature fluids. The material properties and loading were assumed to be random variables. Thermal stresses that are generated along radial, axial, and tangential directions are generally computed using very complex analytical expressions. To circumvent such an issue, probability theory and mathematical statistics have been applied to many engineering problems, which allows determination of the safety both quantitatively and objectively based on the concepts of reliability. Monte Carlo simulation methodology is used to study the probabilistic characteristics of thermal stresses, and was implemented to estimate the probabilistic distributions of stresses against the variations arising due to material properties and load. A 2-D probabilistic finite element code was developed in MATLAB, and the deterministic solution was compared with ABAQUS solutions. The values of stresses obtained from the variation of elastic modulus were found to be low compared to the case where the load alone was varying. The probability of failure of the pipe structure was predicted against the variations in internal pressure and thermal gradient. These finite element framework developments are useful for the life estimation of piping structures in high-temperature applications and for the subsequent quantification of the uncertainties in loading and material properties.

A Comparison Between Three- and Two-Dimensional Thermal Finite Element Analysis of the Gas Metal Arc Welding Process

2003 ◽  
Author(s):  
Mohammad S. Davoud ◽  
Xiaomin Deng
Keyword(s):  
Finite Element ◽  
3D Model ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Element Model ◽  
Transient Temperature ◽  
Two Dimensional ◽  
Element Analysis ◽  
Cross Sectional ◽  
2D Model

Predictions of transient temperature distributions in welding can help the selection of welding process parameters that minimize residual stresses. A three-dimensional (3D) thermal finite element model of bead-on-plate gas metal are welding (GMAW) is presented and is used to evaluate a cross-sectional, two-dimensional (2D) counterpart model. While the thermomechanical problem of welding is 3D in nature, it is shown that the 2D model can provide temperature field predictions comparable to those of the 3D model, even though the 2D model tends to predict peak temperatures higher than those of the 3D model. Both types of model predictions are compared to welding test measurements.

Simple Benchmark Problems for Finite Element Weld Residual Stress Simulation

2013 ◽  
Author(s):  
Mike C. Smith ◽  
Steve Bate ◽  
P. John Bouchard
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Phase Transformation ◽  
Solid State ◽  
Residual Stresses ◽  
Benchmark Problems ◽  
Transient Temperature ◽  
Beam Specimen ◽  
Weld Residual Stress ◽  
Solid State Phase Transformation

Finite element methods are used increasingly to predict weld residual stresses. This is a relatively complex use of the finite element method, and it is important that its practitioners are able to demonstrate their ability to produce accurate predictions. Extensively characterised benchmark problems are a vital tool in achieving this. However, existing benchmarks are relatively complex and not suitable for analysis by novice weld modellers. This paper describes two benchmarks based upon a simple beam specimen with a single autogenous weld bead laid along its top edge. This geometry may be analysed using either 3D or 2D FE models and employing either block-dumped or moving heat source techniques. The first, simpler, benchmark is manufactured from AISI 316 steel, which does not undergo solid state phase transformation, while the second, more complex, benchmark is manufactured from SA508 Cl 3 steel, which undergoes solid state phase transformation during welding. A number of such beams were manufactured using an automated TIG process, and instrumented with thermocouples and strain gauges to record the transient temperature and strain response during welding. The resulting residual stresses were measured using diverse techniques, and showed markedly different distributions in the austenitic and ferritic beams. The paper presents the information necessary to perform and validate finite element weld residual stress simulations in both the simple austenitic beam and the more complex ferritic beam, and provides performance measures for the austenitic beam problem.

Temperature Profiles in a Finite Element Thermal Model of the Prostate Region Under Hyperthermia Treatment

1990 ◽  
Vol 189 ◽  
Author(s):  
Indira Chatterjee ◽  
Roy E. Adams ◽  
Namdar Saniei
Keyword(s):  
Finite Element ◽  
Phased Array ◽  
Blood Perfusion ◽  
Element Model ◽  
Bioheat Transfer ◽  
Transient Temperature ◽  
Temperature Profiles ◽  
Hyperthermia Treatment ◽  
Finite Element Software ◽  
Transient Temperature Distribution

ABSTRACTThe detailed transient temperature distribution in an inhomogeneous model of a cross section through the prostate region of the human body undergoing hyperthermia treatment forcancer has been calculated. The finite element method has been used to solve the bioheattransfer equation. A commercially available finite element software package called ANSYS® has been adapted to the present problem.The model consists of 523 triangular elements and incorporates a tumor in the prostate.The hyperthermia device under test is an Annular Phased Array consisting of dipole antennas. The model is surrounded by a bolus of deionized water. The calculated electromagnetic energy distribution is input into the bioheat transfer equation and the resulting temperature distributions calculated.The increase in blood perfusion rates due to heating is incorporated into the model. Detailed transient temperature profiles in the finite element model are presented for various values of blood perfusion rates in the tumor and surrounding tissues. It is observed that the Annular Phased Array is effective in raising the temperature of the tumor to therapeutic values.

scholarly journals Determination of temperature and thermal stresses distribution in power boiler elements with use inverse heat conduction method

2011 ◽  
Vol 32 (3) ◽  
pp. 191-200 ◽  
Author(s):  
sławomir Grądziel
Keyword(s):  
Boundary Condition ◽  
Heat Conduction ◽  
Temperature Distribution ◽  
Thermal Stresses ◽  
Thermal Boundary Condition ◽  
Transient Temperature ◽  
Inverse Heat Conduction ◽  
Transient Temperature Distribution ◽  
Power Boiler

Determination of temperature and thermal stresses distribution in power boiler elements with use inverse heat conduction method The following paper presents the method for solving one-dimensional inverse boundary heat conduction problems. The method is used to estimate the unknown thermal boundary condition on inner surface of a thick-walled Y-branch. Solution is based on measured temperature transients at two points inside the element's wall thickness. Y-branch is installed in a fresh steam pipeline in a power plant in Poland. Determination of an unknown boundary condition allows for the calculation of transient temperature distribution in the whole element. Next, stresses caused by non-uniform transient temperature distribution and by steam pressure inside a Y-branch are calculated using the finite element method. The proposed algorithm can be used for thermal-strength state monitoring in similar elements, when it is not possible to determine a 3-D thermal boundary condition. The calculated temperature and stress transients can be used for the calculation of element durability. More accurate temperature and stress monitoring will contribute to a substantial decrease of maximal stresses that occur during transient start-up and shut-down processes.

An Inverse Finite Element Method for the Analysis of Stationary Arc Welding Processes

1986 ◽  
Vol 108 (4) ◽  
pp. 734-741 ◽  
Author(s):  
Y. F. Hsu ◽  
B. Rubinsky ◽  
K. Mahin
Keyword(s):  
Finite Element ◽  
Arc Welding ◽  
Computer Code ◽  
Transient Temperature ◽  
Work Piece ◽  
Transient Temperature Distribution ◽  
Interpolation Procedure ◽  
Solid Region ◽  
Solid Liquid Interface ◽  
Welding Processes

An inverse finite element computer code was developed to facilitate the experimental analysis of two-dimensional stationary arc welding processes. The method uses transient temperature data from thermocouples imbedded in the solid region of the work piece to determine through a Newton–Raphson interpolation procedure the transient position of the solid–liquid interface and the transient temperature distribution in the solid region of the work piece. The accuracy of the method was demonstrated through comparison with results obtained with a direct finite element code and through comparison with experiments.

Transient temperature distribution in insulated pavements—predictions vs. observations

1970 ◽  
Vol 7 (3) ◽  
pp. 275-284 ◽  
Author(s):  
D. M. Ho ◽  
M. E. Harr ◽  
G. A. Leonards
Keyword(s):  
Transient Temperature ◽  
Site Conditions ◽  
Two Dimensional ◽  
Ambient Conditions ◽  
Layered Systems ◽  
Temperature Variations ◽  
Finite Difference Technique ◽  
Transient Temperature Distribution ◽  
Temperature Distributions ◽  
Number Of Layers

Based on a finite difference technique, computer programs have been developed whereby temperature variations in layered systems as a function of position and time may be computed under conditions of both one- and two-dimensional heat flow by conduction. No limitations are imposed on the number of layers, or on the form of the initial and boundary temperature conditions. Variations in thermal properties of the materials with temperature and location, and the non-linear relation between amount of water frozen as a function of temperature, are directly taken into account. Comparison of predictions with actual measurements demonstrate that accurate forecasts of temperature distributions as a function of time can be made when prevailing ambient conditions are known. Even if the site conditions can be evaluated only approximately sufficiently reliable predictions can be made for design purposes.

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