void ratio and permeability

[LucaIgnazio93]

Hi guys, this is a porous elastic approch for modelling cartillages. I can't understand how can be void ratio 0 but permeability 1e-08 in a porous elastic material? Besides, why defining 0 as void ratio for the material, but adding an initial void ratio field? Is it a way to define initial and final void ratio?
*Permeability, specific=9.84e-06
1e-08,0.
USER
** PREDEFINED FIELDS
**
*Initial Conditions, TYPE=RATIO
VOIDR, 4.
**

 

[btrueblood]

All materials are permeable in some degree - hydrogen and helium are notorious for permeating through metal tank walls. So, you have a basic permeability of a material to a specific fluid of interest. Add voids and you reduce the effective barriers to the free motion of the fluid.