Inelastic deformations of ceramic powders and granular materials (including the granular/solid transition occurring during forming of ceramic powders) can be described with the yield function proposed by Bigoni and Piccolroaz.
This function is not defined outside the yield locus, so that ‘gradient-based’ integration algorithms of elastoplasticity cannot be directly employed.
Therefore, two ad hoc algorithms are proposed: (i.) an explicit integration scheme based on a forward Euler technique with a ‘centre-of-mass’ return correction and (ii.) an implicit integration scheme based on a ‘cutoff-substepping’ return algorithm.
Iso-error maps and comparisons of the results provided by the two algorithms with two exact solutions show that both the proposed algorithms perform correctly and accurately.
L.P..A. gratefully acknowledges financial support from European Union FP7-INTERCER2 project under contract number PIAP-GA-2011-286110.