Finite element analysis of welded beam-to-column joints in aluminium alloy EN AW 6082 T6

Shell elements are used to model welded beam-to-column joints in alloy EN AW 6082 T6, and the results are compared with experimental data from the literature. The textured alloy is modelled using an anisotropic plasticity model and the inhomogeneous work-hardening properties of the heat-affected zone (HAZ) are accounted for in the material modelling. In order to represent the geometry as accurately as possible, a varying thickness of the shell elements is used in the various parts of the joints. It is found that the numerical results are strongly mesh dependent. To obtain reliable results for both strength and ductility, it is proposed to introduce non-local plastic thinning in the HAZ. This procedure reduces the mesh dependence of the strain localization, at the cost of introducing one additional parameter, namely the radius of the non-local domain.