User Define Failure Criterion with Holzapfel Model

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.

Sounds interesting. Please keep us updated on your progress with XFEM for soft tissues.

I have not use the UDMGINI feature (I mainly use UMAT and VUMAT for abaqus). I have created multiple implementations of the Holzapfel-Gasser-Ogden model, and also of various damage models. It works great in UMAT and VUMAT functions.

-Jorgen