*CONTACT PERMEABILITY

Specify fluid permeability contact property.

This option is used to modify pore fluid permeability in a surface interaction model. It must be used in conjunction with the SURFACE INTERACTION option. If this option is omitted, the intended idealized behavior is no resistance to fluid flow (infinite permeability) across an interface while contact is active and for clearances up to a default tolerance distance, which is approximated with a penalty method (large permeability) for general contact and directly enforced for contact pairs.

Related Topics
*SURFACE INTERACTION
*SOILS
In Other Guides
Pore fluid contact properties
Coupled pore fluid diffusion and stress analysis

ProductsAbaqus/Standard

TypeModel data

LevelModel

Optional parameters

CONSTRAINT METHOD
Set this parameter equal to the constraint enforcement method. The default setting and usage of this parameter depends on whether the contact permeability is specified on the data lines.

Set CONSTRAINT METHOD=DIRECT to directly enforce the intended physical model for contact permeability without approximation.

  • If contact permeability is specified on the data lines, this setting is the default and must be in effect.
  • If contact permeability is not specified on the data lines, this setting is the default for contact pairs and can optionally be used for general contact. Matching pore pressures across the interface are strictly enforced (corresponding to infinite contact permeability).

Set CONSTRAINT METHOD=PENALTY to numerically approximate the enforcement of matching pore pressures across the interface.

  • If contact permeability is specified on the data lines, this setting is not applicable and not allowed.
  • If contact permeability is not specified on the data lines, this setting is the default for general contact and can optionally be used for contact pairs.

CUTOFF FLOW ACROSS

Set this parameter equal to a cutoff clearance distance above which no fluid flow occurs across a contact interface.

CUTOFF GAP FILL

Set this parameter equal to a cutoff clearance distance above which no fluid flow occurs into or out of a contact interface due to changes in clearance distance.

DEPENDENCIES

Set this parameter equal to the number of field variables on which the contact permeability, k, depends.

Data lines to define the contact permeability, k, directly

First line

  1. Contact permeability, k. (Units of L2TM−1.)

  2. Contact pressure, pc⁢o⁢n⁢t⁢a⁢c⁢t.

  3. Average pore pressure, pp⁢o⁢r⁢e.

  4. Average temperature, θ¯.

  5. Average value of the first field variable, f1¯.

  6. Average value of the second field variable, f2¯.

  7. Etc.

Repeat this data line as often as necessary to define the dependence of contact permeability on the contact pressure, average surface pore pressure, average surface temperature, and the average of any predefined field variables on the surfaces.