A review on material fracture mechanism in incremental sheet forming

In incremental sheet forming (ISF), including single point incremental forming (SPIF) and double side incremental forming (DSIF), the material formability can be significantly enhanced when compared with conventional sheet forming processes. The material deformation in ISF is far more complicated because of the combined material deformation under stretching, bending, shearing, and cyclic loading, with an additional effect of compression in DSIF. Despite extensive investigation on material deformation during ISF, no theory has yet been widely agreed to explain different types of the material fracture behavior observed in ISF experiments. This paper presents a comprehensive review on the formability enhancement in ISF and proposes possible fracture mechanisms explaining the different types of fracture behavior observed in the experimental investigations. Discussions are presented to outline the current research progress and possible solutions to overcome the current ISF process limitations because of the material processing failure due to fracture.