http://www.me.sc.edu/fs/pdf/5-FSW%20steel%20JMPT.pdf

Numerical simulation of transient temperature and residual stresses in friction stir welding of 304L stainless steel

Simulation of welding has advanced from the analysis of laboratory setups to real engineering applications during the last three decades. This development is outlined and the directions for future research are summarized in this review, which consists of three parts. This part shows that the increased complexity of the models gives a better description of the engineering applications. The important development of material modeling and computational efficiency are outlined in Parts 2 and 3, respectively.

Finite element modeling and simulation of welding part 1: increased complexity

Simulation of welding has advanced from the analysis of laboratory setups to real engineering applications during the last three decades. This development is outlined and the directions for future research are summarized in this review, which consists of three parts. The material modeling is maybe the most crucial and difficult aspect of modeling welding processes. The material behavior may be very complex for the large temperature range considered.

Finite element modeling and simulation of welding. part 2: improved material modeling

Effects of temperature-dependent material properties on welding simulation

\n Physics-informed neural networks (PINNs) have gained popularity across different engineering fields due to their effectiveness in solving realistic problems with noisy data and often partially missing physics. In PINNs, automatic differentiation is leveraged to evaluate differential operators without discretization errors, and a multitask learning problem is defined in order to simultaneously fit observed data while respecting the underlying governing laws of physics. Here, we present applications of PINNs to various prototype heat transfer problems, targeting in particular realistic conditions not readily tackled with traditional computational methods. To this end, we first consider forced and mixed convection with unknown thermal boundary conditions on the heated surfaces and aim to obtain the temperature and velocity fields everywhere in the domain, including the boundaries, given some sparse temperature measurements. We also consider the prototype Stefan problem for two-phase flow, aiming to infer the moving interface, the velocity and temperature fields everywhere as well as the different conductivities of a solid and a liquid phase, given a few temperature measurements inside the domain. Finally, we present some realistic industrial applications related to power electronics to highlight the practicality of PINNs as well as the effective use of neural networks in solving general heat transfer problems of industrial complexity. Taken together, the results presented herein demonstrate that PINNs not only can solve ill-posed problems, which are beyond the reach of traditional computational methods, but they can also bridge the gap between computational and experimental heat transfer.

Physics-Informed Neural Networks for Heat Transfer Problems

Transient and Residual Thermal Strain-Stress Analysis of GMAW

The thermal history of a weld joint produced by the gas metal arc (GMA) welding process is analyzed by using a three-dimensional finite element model. The problem consists of one in which the finite element mesh is growing continuously in time in order to accommodate metal transfer in CMA welding. The procedure of how to incorporate the growth of the mesh in the analysis has been described. The finite element program ABAQUS, along with a few user subroutines, was employed to obtain the numerical results. Temperature-dependent thermal properties, effect of latent heat, and the convective and radiative boundary conditions are included in the model. Numerically predicted sizes of the heat-affected zone and the melt-pool zone are compared with the experimentally observed val-

Finite element analysis of three-dimensional transient heat transfer in gma welding. .

The thermal history of a weld joint produced by the gas metal arc (GMA) welding process is analyzed by using a three-dimensio nal finite element model. The problem consists of one in which the finite element mesh is growing continuously in time in order to accom­ modate metal transfer in CMA welding. The procedure of how to incorporate the growth of the mesh in the analysis has been described. The finite element program ABAQUS, along with a few user subroutines, was employed to obtain the numerical results. Temperature-dependent thermal proper­ ties, effect of latent heat, and the convec­ tive and radiative boundary conditions are included in the model. Numerically predicted sizes of the heat-affected zone and the melt-pool zone are compared with the experimentally observed val- tion for the numerical methods that can take into account the nonlinearities involved in the process and provide a practical solution. The finite element method has developed into a powerful tool to solve problems governed by dif­ ferential equations (Ref. 5), including tran­ sient heat conduction analysis of complex shapes (Refs. 6, 7). While the technique has been used fairly well to simulate and model the gas tungsten arc welding (GTAW) process by Friedman (Refs. 8- 10), Krutz, etal. (Ref. 11), Tekriwal, etal. (Ref. 13), and Mahin, et al. (Ref. 14), not many attempts have been made to mod­ el a gas metal arc welding process. Hibbitt and Marcal (Ref. 12) analyzed an axisym- metrical example with addition of molten filler material. However, the material properties were updated only periodi­ cally in their model. The work presented here, to the best of the authors' knowl-

Finite Element Analysis of Three-Dimensional Transient Heat Transfer in GMA Welding The data generated in this study can be used to determine the heating and cooling rate, weld pool shape and HAZ

Finite element modeling of arc welding processes.

A 3-D transient heat flow analysis by finite element methods was used to calculate heat input during TIG welding with the torch inclined at an angle. Temperature distribution, molten pool size and dimensions of the heat affected zone were determined. Effects of varying the rate of shielding gas flow were assessed. Calculated results were compared with measurements made on single pass TIG welds on mild steel plate with the torch at 0, 30 or 45Deg from vertical.

J. Mazumder

Papers

Transient and Residual Thermal Strain-Stress Analysis of GMAW

Finite element analysis of three-dimensional transient heat transfer in gma welding. .

Finite Element Analysis of Three-Dimensional Transient Heat Transfer in GMA Welding The data generated in this study can be used to determine the heating and cooling rate, weld pool shape and HAZ

Finite element modeling of arc welding processes.

Effect of torch angle and shielding gas flow on tug welding - a mathematical model