Simulation of Weld Pool Dynamics and Subsequent Thermal Stress Analysis of Welded Joint Under Gas Tungsten Arc Welding

2011 ◽  
Author(s):  
Debamoy Sen ◽  
Kenneth S. Ball ◽  
Mark A. Pierson
Keyword(s):  
Thermal Stress ◽  
Stress Analysis ◽  
Weld Pool ◽  
Thermal Stresses ◽  
Welding Parameters ◽  
Thermal Profile ◽  
Thermal Stress Analysis ◽  
Gas Tungsten Arc ◽  
Welded Structure ◽  
Gas Tungsten

Thermal stresses in the weldment influence the load carrying capacity of the welded structure and have significant practical implications. Various welding parameters (like, welding speed, current, surfactant activity, etc.) influence the weld pool dynamics, which in turn affect the thermal history of the workpiece. Hence, the complete weld pool dynamics need to be considered for predicting an accurate thermal profile in the welded structure before a thermal stress analysis is conducted. In this study, the thermal profile created due to fluid flow, heat transfer and phase change during Gas Tungsten Arc (GTA) welding is incorporated in conducting a thermal stress analysis of the welded workpiece. The effect of preheat on the developed thermal stresses is also analyzed.

Coupled Field Analysis of a Gas Tungsten Arc Welded Butt Joint—Part I: Improved Modeling

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
D. Sen ◽  
M. A. Pierson ◽  
K. S. Ball
Keyword(s):  
Weld Pool ◽  
Welding Process ◽  
Butt Joint ◽  
Accurate Estimation ◽  
Mathematical Framework ◽  
Welded Structures ◽  
Thermally Induced ◽  
Gas Tungsten Arc ◽  
Welded Structure ◽  
Gas Tungsten

Thermally induced residual stresses due to welding can significantly impair the performance and reliability of welded structures. From a structural integrity perspective of welded structures, it is necessary to have an accurate spatial and temporal thermal distribution in the welded structure before stress analysis is performed. Existing research has ignored the effect of fluid flow in the weld pool on the temperature field of the welded joint. Previous research has established that the weld pool depth/width (D/W) ratio and heat affected zone (HAZ) are significantly altered by the weld pool dynamics. Hence, for a more accurate estimation of the thermally induced stresses it is desired to incorporate the weld pool dynamics into the analysis. Moreover, the effects of microstructure evolution in the HAZ on the mechanical behavior of the structure need to be included in the analysis for better mechanical response prediction. In this study, a three-dimensional numerical model for the thermomechanical analysis of gas tungsten arc (GTA) welding of thin stainless steel butt-joint plates has been developed. The model incorporates the effects of thermal energy redistribution through weld pool dynamics into the structural behavior calculations. Through material modeling the effects of microstructure change/phase transformation are indirectly included in the model. The developed weld pool dynamics model includes the effects of current, arc length, and electrode angle on the heat flux and current density distributions. All the major weld pool driving forces are included, namely surface tension gradient induced convection, plasma induced drag force, electromagnetic force, and buoyancy. The weld D/W predictions are validated with experimental results. They agree well. The workpiece deformation and stress distributions are also highlighted. The mathematical framework developed here serves as a robust tool for better quantification of thermally induced stress evolution and distribution in a welded structure by coupling the different fields in a welding process.

scholarly journals A Numerical Three-Dimensional Thermal Stress Analysis for Cooled Blades

1989 ◽  
Author(s):  
J. Srinivasan ◽  
R. M. S. Gowda ◽  
R. Padmanabhan
Keyword(s):  
Thermal Stress ◽  
Stress Analysis ◽  
Thermal Stresses ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Stress System ◽  
Blade Profile ◽  
Thermal Stress Analysis ◽  
State Of Stress ◽  
Second Degree

A modern gas turbine engine subjects the turbine rotor blade to severe thermal stress conditions. Thermal stresses constitute a major part of the state of stress in the blade. Improved blade design with optimum weight, long creep life and structural integrity necessitates more refined thermal stress analysis. In this work a plane blade profile is assumed to take the form of a second degree surface with constant curvatures. The general second degree polynomial allows all the six static equilibrium equations to be considered in evaluating the strained surface. The three dimensional state of stress is determined considering the lateral deformations of the blade profile. A numerical procedure is adopted to solve the non-linear simultaneous equations arising due to the self equilibrating thermal stress system. The results are close to that of original analysis. However, this procedure employs all the necessary equilibrium conditions and relaxes the constraints imposed due to the plane surface assumption to a lower level. The method of analysis is discussed in this paper.

scholarly journals STEADY-STATE THERMAL STRESS ANALYSIS OF GEARBOX CASING BY FINITE ELEMENT METHOD

2013 ◽  
pp. 118-122
Author(s):  
P. D. PATEL ◽  
D. S. SHAH
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stress ◽  
Stress Analysis ◽  
Thermal Stresses ◽  
Dimensional Structure ◽  
Thermal Stress Analysis ◽  
Problem Solve ◽  
Von Mises ◽  
Element Method

This paper contains the gearbox casing analysis by finite element method (FEM). In previous study the thermal stresses have been affected on the performance of gearbox casing during the running conditions. So, this problem solve by thermal stress analysis method. Thermal stress analysis is the process of analyzing the effect of thermal and mechanical loads, and heat transfer of gearbox casing. In this paper, thermal stresses have been analyzed on gearbox casing, and thus temperature field has been coupled to the 3-Dimensional structure model using Fem. Paper also describes convection effect between the inner-surface of casing and the circulating oil which has been found small and thus neglected. Study of equivalent von-mises stresses in inner and outer gearbox casing with the coupled method has been done using ANSYS software. Result shows thermal stress analysis and deformation value under the action of force and heat. Result finds the thermal stress of the gearbox casing is 68.866 Mpa and 0.15434 mm for the deformation of the gearbox casing.

Plane Thermal Stress Analysis of an Orthotropic Cylinder Subjected to an Arbitrary, Transient, Asymmetric Temperature Distribution

2002 ◽  
Vol 69 (5) ◽  
pp. 632-640 ◽  
Author(s):  
K.-C. Yee ◽  
T. J. Moon
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Temperature Distribution ◽  
Analytical Solution ◽  
Stress Analysis ◽  
Stress Function ◽  
Thermal Stresses ◽  
Shear Stresses ◽  
Thermal Stress Analysis ◽  
Interlaminar Shear

A closed-form, analytical solution is presented for the transient, plane thermal stress analysis of a linearly elastic, homogeneously orthotropic hollow cylinder subjected to an arbitrary temperature distribution. The thermoelastic solution, obtained by a stress function approach, can be used as the basis for the corresponding thermoviscoelastic solution for thermorheologically simple viscoelastic materials by invoking the viscoelastic Correspondence Principle. This solution can also be directly extended to the class of weakly inhomogeneously orthotropic cylinders using perturbation methods. The transient asymmetric temperature field is characterized by Fourier-Bessel eigenfunction expansions. The analytically derived stress function satisfies a linear, fourth-order inhomogeneous partial differential equation and the Cesaro integral conditions, which assure the existence of a single-valued displacement field. The corresponding thermal stresses are then computed by the stress-stress function relations. A key feature of the analytical solution is that the hoop, radial, and shear stresses, due to the transient arbitrary temperature distribution, are expressed explicitly in terms of the scalar temperature field. A polymer composite example is presented to validate the current method and to qualitatively illustrate the distribution of thermal stresses due to an asymmetric temperature distribution. Numerical results are presented for the thermally driven hoop, radial and (interlaminar) shear stresses in a hollow, hoop-wound glass/epoxy cylinder. This analysis demonstrates that potentially debilitating interlaminar shear stresses can develop in laminated composites when subjected to an even modest transient asymmetric temperature distribution. Their magnitudes depend on the severity of the spatial and temporal thermal gradients in the circumferential direction. While still relatively low compared to the hoop stress, the shear stress may cause thermal failure due to the typically low interlaminar shear strengths of laminated composite materials.

Validation of Advanced Composite Thermal Stress Analysis Methods

1987 ◽  
Vol 109 (1) ◽  
pp. 40-46 ◽  
Author(s):  
J. G. Crose ◽  
R. L. Holman ◽  
N. J. Pagano
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stress ◽  
Stress Analysis ◽  
Thermal Stresses ◽  
The Finite Element Method ◽  
Property Variation ◽  
Thermal Stress Analysis ◽  
Total Potential ◽  
Element Method

The thermal stress analysis of thermally degrading tape wound phenolic composites in rocket nozzles is complicated by the extreme variation of properties with temperature, combined with steep temperature gradients on the order of 50,000° F/in. This study applied two very different numerical approaches to the same problem of predicting thermal stresses in a moderately thick conical frustum. One method uses a variational theorem derived by Reissner while the other applies the classical finite element method based on minimization of the total potential energy. The good agreement of the two methods appears to validate the results and an extensive convergence study is presented that identifies the magnitude of errors in the finite element method as a function of element density. A modification to the finite element method to account for intra-element material property variation is shown to improve the convergence of the procedure.

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