An anisotropic stress based criterion to predict the formability and the fracture mechanism of textured zinc sheets

The Forming Limit Diagram (FLD) of a textured zinc sheet has been identified via tensile and bulge tests. The strong anisotropy of the sheet is reflected in the tensile tests, and even more strikingly in the formability measured from the bulge tests. The dependence of the FLD on the orientation of the sheet is unusual, and is shown to be well captured by an anisotropic stress based criterion. The criterion is also able to predict the observed cracks orientations.

► The formability of a zinc sheet has been determined through tensile and bulge tests.
► A strong anisotropy in formability appears when comparing two loading directions.
► The Forming Limit Diagram has a very unusual shape for one sheet orientation.
► A proposed anisotropic stress based criterion predicts well the sheet formability.
► Cracks orientations are also well predicted by the proposed model.