In the presence of materi_damage , the materi_stress follows:
For the damage, the group_materi_damage_mazars model is available:
contains the positive principal strains.
The parameter is given by the ratio
where contains the total strains (both negative and positive).
The parameter is the strain threshold for damage;
other material parameters are
Typically for concrete:
You can combine damage freely with plasticity models or other material behavior.