A macro-micro-multi-level modeling scheme to study the effect of particle distribution on wrap-bendability of AA5754 sheet alloys

A two-level finite element model to simulate wrap bending of flat sheet metal has been developed. Firstly, a sample sized plane strain analysis is performed and the location of most severe deformation is identified. Then a plane strain sub-model incorporating microstructural input, such as second phase particles at this location, is performed. The results show that models with particles distributed primarily in stringers exhibit lower bendability than those containing a random distribution of particles. This is consistent with the difference in bendability observed between continuous cast (CC) and direct chill cast (DC) AA5754 alloys which have characteristic stringer and random particle distributions. The morphology of cracking in the model with stringers is similar to that observed in AA5754 CC sheets. The crack initiates at the surface between particles or near particles and propagates along local shear bands to other stringers in the bulk or jumps from one stringer to another.