Cartilage in ABAQUS

Hello,

Im interested in modelling contact between cartilage surfaces in ABAQUS. I have had some success using poro-hyperelastic models in the *soil abaqus solver, which seem to give reasonable results, but they are computationally expensive and difficult to get working.

Some researchers ignore the pore fluid flow and just use hyperelastic material properties. The literature says that initial compressive behaviour can be approximated using incompressible material properties, while the long-term or equilibrium behaviour is actually very compressible. Ive more or less confirmed this by manually changing the D1 parameter of a hyperelastic material model without pore fluid flow, where simple compression with D1(t) gives the same compression as the poro-hyperelastic model at time t, if that makes sense.

It would be great, however, to have a material model which can span from early to long-term response.

Has anyone tried using a viscoelastic material where the shear modulus stays the same but bulk modulus decreases so drastically? Im finding that either the simulations fail, or I cant match the response of the poro-hyperelastic model. My gut says it *should* work, but Ive been struggling with this off and on for over a month with little success.

Would just like to know if someone else has already tried this and has any tips, or can confirm that it just doesnt really work.

Help is greatly appreciated.

Ryan

Sounds like a great idea. I have not tried that approach, but I agree with your that it should work.

I would solve that by using a suitable UMAT subroutine. The [URL= https://polymerfem.com/content.php?10-PolyUMod ]PolyUMod [/URL]library does not contain that specific features, but I would be happy to work with you to add it...

-Jorgen