Effect of metal inert gas welding on the behaviour and strength of aluminum stiffened plates

• A 3D, thermo-structural nonlinear finite element model to simulate the metal inert gas welding in aluminum stiffened plates.
• The welding induced residual stress distribution and the HAZ width were studied for various geometries of the stiffened plates.
• Reductions in the ultimate strength of stiffened plates as affected by the residual stress and HAZ were presented.

This paper investigated the effect of a 3D simulated metal inert gas (MIG) welding induced heat affected zone (HAZ), residual stress and distortion fields on the behaviour of aluminum stiffened plates under compressive loading. A two-step, thermo-structural finite element model was developed for the simulation of the welding process and the model was verified using the available experimental results. The welding induced HAZ, residual stress and distortion were then studied for tee-bar stiffened aluminum plates of various geometries. The effect of these welding induced imperfections on the load vs. shortening curves, buckling mode, and the post-buckling behaviour of each stiffened plate geometry were investigated. It was found that welding induced tensile and compressive residual stresses ranged from 72 to 77% and 18–36% of the base metal yield stress, respectively. The width of the HAZ around the weld line increased as the plate slenderness increased. The reduction in buckling strength of the tee-bar aluminum stiffened plates due to the presence of the HAZ and residual stress was as much as 10% and 16.5% respectively.