One of the most widely involved operations in sheet metal forming processes in aircraft industry is bending, particularly, air bending as a simple process. For this reason, the bendability of aluminum alloys is an important material property, which determines the minimum radius to which a sheet may be bent without cracking. Hence, the challenging issue, on which this paper focuses, is to predict this material parameter from other material parameters commonly measured during standard tensile tests. For this prediction, a finite element model and a response surface model are elaborated and, as a result, a relatively simple formula is proposed to calculate the minimum bending radius from the reduction in the area at fracture, the strain hardening exponent, and the yield stress, which are material parameters available from tensile tests.
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