A review on the evaluation of formability in sheet metal forming

In sheet metal forming processes, formability is a critical material property that needs to be estimated before the production of forming parts. Some popular tools used in the literature to study the formability of the sheet metal are: Forming Limit Diagram (FLD), Fracture Forming Limit Diagram (FFLD) and Forming Stress Limit Diagram (FSLD). Experimental and theoretical approaches developed by different researchers are reviewed here including the most recent method, namely, Polar Effective Plastic Strain FLD (PEPS-FLD).