Sheet metal formability predicted by using the new (1993) Hill's yield criterion

摘要

The paper attempts to settle a mathematical model in order to predict theoretically Forming Limit Diagrams (FLD's) by using the Marciniak-Kucznski analysis with the new orthotropic yield criterion (transversaly isotropic version) proposed by Hill in 1993. The model is solved numerically. The algorithm is very flexible, so that it allows to study the influence of various parameter upon FLD's: strain hardening coefficient (n), strain-rate sensitivity index (m), normal anisotropy coefficient (r), geometrical non-homogeneity coefficient (f), ratio between uniaxial and biaxial yield stress (delta_u/delta_b) (a).