Finite Element Analyses of Stress Intensity Factor Solutions for Discontinuous Gas Metal Arc Welds under Lap-Shear Loading Conditions

The distributions of the mode I and mode II stress intensity factor solutions along the fronts of the pre-existing cracks of continuous and discontinuous gas metal arc welds in lap-shear specimens are investigated by three-dimensional finite element analyses. Two-dimensional plane strain finite element analyses were first carried out in order to obtain the computational stress intensity factor solutions for the idealized and realistic weld geometries as the references. Further, the stress intensity factor solutions for realistic welds obtained from the two-dimensional finite element analyses are presented for unequal sheet thicknesses for future engineering applications. Then the stress intensity factor solutions for continuous and discontinuous welds were obtained by three-dimensional finite element analyses. The computational results indicate that the distributions of the mode I and mode II stress intensity factor solutions for the discontinuous welds are quite different from those for the continuous welds. For continuous welds, both the mode I and II stress intensity factor solutions are higher in the middle of the crack front and lower toward the free surfaces. For discontinuous welds, both the mode I and II stress intensity factor solutions become higher near the weld ends or discontinuities with consideration of contact.