| This study focuses on the computational aspects of elasto-plastic modeling of metals obeying the von-Mises ({dollar}Jsb2{dollar}) yield criterion and that are subjected to plane stress conditions. Numerical simulation of elasto-plastic material behavior involves constitutive relations, the characteristics and properties of which affect the overall performance.; Spectral analysis of the tangent material operator is conducted at different stress states to characterize the incremental behavior of the material operator in various respects (i.e. positive definiteness, solution non-uniqueness, instability, localization, etc{dollar}...{dollar}). Contrary to conventional expectation, it is found that, in a strain driven environment, the direction of neutral loading may not coincide with the tangent to the yield surface in two dimensional stress space. The assumptions of perfect plasticity, strain-hardening and strain-softening are considered for associated and non-associated plasticity.; In predicting the behavior of {dollar}Jsb2{dollar} elasto-plastic solids in plane stress, a numerical integration (return mapping) algorithm is derived for mixed hardening. The derivation is carried-out in the spirit of the Generalized Mid-point Rule. It is based on the exact nonlinear expression of the plastic consistency condition. The accuracy of the algorithm is assessed on the constitutive level. The numerical efficiency is discussed in terms of advantages, disadvantages and a quantitative comparison with respect to existing plane stress implicit schemes. |
