Before revision: The Bigoni–Piccolroaz yield criterion is a seven-parameter surface defined as: where p, q and are invariants dependent on the stress tensor, while is the "meridian" function describing the pressure-sensitivity and is the "deviatoric" function Podgórski, J.
After revision: :The Bigoni–Piccolroaz yield criterion is a seven-parameter surface defined as: where p, q and are invariants dependent on the stress tensor, while is the "meridian" function describing the pressure-sensitivity and is the "deviatoric" function Podgórski, J.