Numerical simulation of sheet metal forming processes using a new yield criterion

The paper is focused on the development of a new phenomenological yield criterion able to describe the inelastic response of sheet metals subjected to cold forming. The model consists in two components: the equivalent stress and the hardening law. The equivalent stress is a function incorporating 8 material parameters. Due to these parameters, the new formulation is able to describe four normalized yield stresses (y(0), y(45), y(90) y(b)) and four coefficients of plastic anisotropy (r(0), r(45) r(90), r(b)). The hardening law is defined as a linearly asymptotic function containing 4 material parameters. The numerical tests presented in the last section of the paper prove the capability of the elastoplastic constitutive models based on the new yield criterion to model the caring as well as the wrinkling phenomena accompanying the deep-drawing process.