*GAP DIFFUSIVITY

Specify ion diffusion contact property.

This option is used to modify ion diffusion 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 ionic flux flow (infinite diffusivity) across an interface while contact is active and for clearances up to a default tolerance distance. Abaqus/Standard approximates this behavior with a penalty method (large diffusivity) for general contact and direct enforcement for contact pairs.

This page discusses:

See Also
*SURFACE INTERACTION
In Other Guides
Electrical Contact Properties

Products Abaqus/Standard

Type Model data

LevelModel

Required parameters

TYPE

Set TYPE=ION CONCENTRATION to define the contact diffusivity, D g .

Optional parameters

CUTOFF FLOW ACROSS

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

CUTOFF GAP FILL

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

DEPENDENCIES

Set this parameter equal to the number of field variables on which the contact diffusivity, D g , depends.

Data lines to define the contact diffusivity, D G , directly

First line

  1. Contact diffusivity, D G . (Units of T–1L.)

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

  3. Average ion concentration, C e ¯ .

  4. Average temperature, θ ¯ .

  5. Average value of the first field variable, f 1 ¯ .

  6. Average value of the second field variable, f 2 ¯ .

  7. Etc.

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