poroelasticity

According to my understanding, there are two ways of prescribing poroelsticity in Abaqus.

One is to use poroelastic material model, and the other is by giving elastic material properties in special states (instantaneous state and long time equilibrium state).

You are using the first method, so you have to give logarithmic bulk modulus, initial void ratio, shear modulus (or Possion's ratio). To answer your question of where they come from, in Abaqus the elastic part of the volumetric behavior of porous materials is
modeled accurately by assuming that the elastic part of the change in
volume of the material is proportional to the logarithm of the pressure
stress. To get the exact formular of bulk modulus in terms of average pressure, you can take a look at Abaqus ducumentation--> Abaqus user's manul -->materials-->elastic mechancial properties-->poroselasticity-->elatic behavior of porous materials

 To use the second method, you have to give instantaneous Young's modulus (instantaneous posson's ratio is assumed to be 1/2 automatically in Abaqus), and long time equilibrium Young's modulous  and long time Possion's ratio. You can not prescribe these properties directly in Abaqus CAE. You have to modify the in put file. There is an example in Abaqus example problems Manual --> soils analysis

Hi,

Isn’t that right, that I can define the poroelastic material also in a different way – as an elastic material with permeability? Like I define the Young’s modulus and Poisson’s ratio of the matrix, and by prescribing the permeability I define the fluid. And all these definition I do in Abaqus CAE.

Michala