Evaluation of hardening laws coupled with shear modified Lemaitre damage model for fracture prediction in incremental sheet forming

Abstract Incremental sheet forming (ISF) is an emerging technology for manufacturing sheet metal components with fewer tools and equipment compared to conventional sheet forming. In this process, forming is generally performed without dies and punches and a simple hemispherical shaped tool can be used for shaping the final component. Forming limit in incremental sheet forming can be defined by the maximum formable wall angle. Finite element analysis can be used for fracture prediction by using a damage model. Also, to define the material flow behaviour hardening law should be incorporated into the finite element model. In this study four different hardening laws were used with shear modified Lemaitre damage model for fracture prediction during ISF of AA1050 alloy. The effectiveness of Hollomon, Johnson-Cook, Ludwigson and Swift hardening laws were compared for fracture prediction. Further, the predicted fracture wall angles were compared with the experimental observations. The results were analysed in terms of damage and strain evolution for the predicted fracture wall angles based on different hardening models.