Viscoplasticity is a model for rate-dependent plasticity. Rate dependent plasticity is important for (high-speed) transient plasticity calculations. It should be used in combination with a plasticity law. Viscoplasticity influences the stresses via the plastic strains.
where
(fluidity constant),
(reference value for
yield function, e.g. the yield stress for Von-Mises plasticity)
and p (power) are user specified parameters for the group_materi_plasti_visco
model.