EN 13445 ANNEX B requires for the gross plastic deformation design check, B.8.2, a linear-elastic ideal-plastic law with Tresca’s yield condition (maximum shear stress condition) and associated flow rule.
I have seen in the manual 6.8.7 that plastic flow algorithms in Calculix are isochoric and the classical von Mises Huber yield condition applies. By other hand I do not see ideal-plastic materials available.
¿Is there any way to sort this to fulfil the code requirement or am I maybe misreading the manual In some way?
When defining the plastic curve for the material just set it to a constant value, that makes it ideal. Sometimes a straight line is considered, I think for pressurized vessels steel a constant value is the right choice, but maybe someone else has better knowledge. Not my field of specialization.
CalculiX uses standard Mises plasticity, the Tresca yield criterion is not available but even Abaqus doesn’t have it. In both programs, you would need UMAT to implement this.
When it comes to perfect plasticity, just define a single point - yield stress and corresponding 0 plastic strain. For example: