Fig. 2.

Illustration of the damage mode classification: regions are highlighted on the initial damage onset surface in principal stress space in 3D (left) and on a 2D projection with ${\sigma }_3={\sigma }_1$ (right). Elements are damaged under local tension (red) or compression (blue) if all principal stress components are positive or negative, respectively. Additionally, hydrostatic damage modes are defined by the sign of the hydrostatic stress: positive hydrostatic stress corresponds to hydrostatic tension (light red) and negative to hydrostatic compression (light blue)