“…This is typically done by splitting the elastic energy density into 2 additive parts related to tension Ψ + and compression Ψ − , respectively, and degrading only Ψ + by (s 2 + k). Different splitting approaches are possible, either by considering the principal strain direction (Miehe et al, 2010) or via a decomposition of the strain energy in volumetric and deviatoric components (Amor et al, 2009), see Ambati et al (2015) for a more detailed discussion. The extension to poroelastic media is possible (Miehe et al, 2015;Mikelic et al, 2015;Lee et al, 2016;Wilson and Landis, 2016), although details in the regularization differ among the various published approaches.…”