Identifying elasto-plastic damage coupling model of laser-welded aluminum alloy by virtual field method and digital image correlation

Abstract The local high temperature of laser welding affects the mechanical damage properties of aluminum alloy. The full-field strain near the weld of the laser-welded aluminum alloy 6061 under uniaxial tension was obtained using digital image correlation. An iterative stress increment method for the isotropically hardened elasto-plastic damage coupling constitutive model is proposed herein based on the combination of a return mapping scheme and the nonlinear virtual field method. The elasto-plastic damage coupling constitutive parameters and its corresponding stress–strain relationship in each subzone around the weld are established. The results show that the plastic strain accumulating in the heat-affected zone is the fastest, where the damage initiation occurs earlier, and the damage evolution speed is faster than that other zones.