INTERPOLATION SCHEME FOR PLASTIC YIELD CRITERIA

In metal plasticity, analysis has been based on yield criteria chosen primarily for mathematical convenience; however, progress with numerical methods is providing a role for criteria which reflect more accurately known material properties. A well-defined analytic form for the yield criterion is required, and in this Note an interpolation scheme is suggested for generating a yield criterion consistent with data obtained in two tests - simple tension and simple shear (e. g. , torsion) - carried out on a metal which is known to be essentially isotropic and where yield is unaffected by the hydrostatic component of stress.