Transient and Residual Thermal Strain-Stress Analysis of GMAW

Abstract

A three-dimensional transient thermomechanical analysis has been performed for the Gas Metal Arc Welding process using the finite element method. Because the heat generated due to elasto-visco-plastic straining in welding is negligible in comparison to the arc heat input, the thermomechanical analysis is uncoupled into two parts. The first part performs a three-dimensional transient heat transfer analysis and computes entire thermal history of the weldment. The second part then uses results of the first part and performs a three-dimensional transient thermo-elastoplastic analysis to compute transient and residual distortions, strains and stresses in the weld. The thermomechanical model incorporates all the thermophysical and mechanical properties of the material as functions of temperature. Boundary conditions used in the numerical simulation are quite general and are matched with the experiment carried out to measure transient strains in the mild steel (0.22 percent carbon steel) weld. Good qualitative agreement was achieved between calculated and measured transient strains.

Modeling of Gas Metal Arc Welding Process Using an Analytically Determined Volumetric Heat Source

“…The values of f1 and f2 are considered as 0.6 and 1.4, respectively, as suggested in published literature. 5,7,14,15,17) The values of a1, a2, b and c in Eq. (4) where a is the radius of the hemisphere.…”

“…The semi major axes, minor axes and depths of the front and the rear semi-ellipsoids are depicted as (a1, b, c) and (a2, b, c), respectively. The power density distribution in the front and the rear heat sources can be written as 5,7,14,17) ....... (3) where the subscript i refers to 1 and 2 corresponding to the front and the rear heat sources, and η is the process efficiency. In Eq.…”

“…[8][9][10][11][12][13]18) The conduction heat transfer based models for GMAW and SAW processes have also remained an effective recourse because of their computational simplicity, flexibility to consider wide-ranging weld joint geometry, and quick adoptability in several numerical analysis software that are widely available. [5][6][7][14][15][16][17] In contrast, the analytical heat transfer models to simulate GMAW process could consider simple joint geometry and constant material properties that usually inhibited accurate prediction of temperature field within the weld pool. 19,20) The majority of the conduction heat transfer based numerical models considered a volumetric heat source to account for the transfer of arc energy in the weld pool and, the heat source dimensions are determined either arbitrarily or based on the measured final weld dimensions that had restricted the predictive capability of these models.…”

“…[1][2][3][4] Although several efforts are published to simulate autogenous fusion welding processes, similar models that can also consider the electrode deposition such as in gas metal arc welding process (GMAW) and submerged arc welding (SAW) are only a few. [5][6][7][8][9][10][11][12][13][14][15][16][17][18] The convective heat transport based have remained as a route to realize heat transfer and fluid flow in weld pool, and the resulting weld pool profile. [8][9][10][11][12][13]18) The conduction heat transfer based models for GMAW and SAW processes have also remained an effective recourse because of their computational simplicity, flexibility to consider wide-ranging weld joint geometry, and quick adoptability in several numerical analysis software that are widely available.…”

Process Induced Residual Stress Effect on Fatigue Lifetime of Automotive Steel Components

“…The transformation plasticity is determined using the model of Leblond [10,11]. The Poisson's ratio has little influence and is supposed to be constant [12]. Fig.…”