I am planning to model crack propagation on soft tissues using XFEM. Since ABAQUS has already the built-in Holzapfel hyperelastic material, this make things a bit easy. Based on the Holzapfel model, there are two terms define on the strain energy function: 1) non-collagenous isotropic ground material 2)collagen fibre. My idea would be to define different damage criterion for the non-collagenous part and the collagen fibre part.
Hence, I would like to know if the user damage subroutine (UDMGINI) has the capability to do such a thing. Based on the documentation, I understand a bit of the UDMGINI function and Ive seen some of the application especially for composite failure. But to apply it with the Holzapfel model seems to puzzle me a bit. If someone can provide some ideas, that would be much appreciated.