Strength Characteristics of Heat-Affected Zones in Welded Aluminum Connections

This study proposes a methodology to predict the capacity of aluminum welded connections. In order to evaluate the material characteristics within the heat-affected zone, an inverse analysis methodology, using full-field measurements of the strain field using digital image correlation, was developed during uniaxial tensile tests on specimens extracted from gas metal arc welded 6061-T6 aluminum alloy plates. The identification of the constitutive law problem was formulated within the Virtual Fields Method. The inverse analysis methodology was compared with an identification process of the material in the vicinity of the weld using a fully coupled multiphysics simulation considering thermal, metallurgical, and mechanical mechanisms during heating and cooling. The simulation accounts for the nonhomogeneous hardening properties within the heat-affected zone to extract the constitutive material laws of a welded join. The proposed simulation methodology was used to analyze the structural response of a plate-square hollow structural section (SHSS) joint subjected to tensile loading. The predicted capacity of the specimens was compared with the experimental findings as well as analyses using Canadian code recommendations. It is shown that it is possible to improve the prediction of the capacity of welded aluminum connection using the Canadian recommendations if the width of the heat-affected zone is reduced to 15 mm instead of the original 25 mm. (C) 2019 American Society of Civil Engineers.