This option is used to define the bulk moduli of solid grains and a
permeating fluid such that their compressibility can be considered in the
analysis of a porous medium. The
POROUS BULK MODULI option cannot be used with the porous metal plasticity
material model. For cohesive elements, this option can be used in conjunction
with the
ELASTIC, TYPE=TRACTION option to define Biot's coefficient. If this option is
omitted, the bulk moduli are assumed to be infinite.
Set this parameter equal to the number of field variable dependencies
included in the definition of the porous bulk moduli. If this parameter is
omitted, it is assumed that the porous bulk moduli are constant or depend only
on temperature.
This parameter is not active for cohesive elements.
Data lines
to define bulk moduli
First
line
Bulk modulus of solid grains. (Units of FL−2.) If
this entry is blank or zero, this value is assumed to be infinite.
Bulk modulus of permeating fluid. (Units of FL−2.)
If this entry is blank or zero, this value is assumed to be infinite.
Temperature.
First field variable.
Second field variable.
Etc., up to five field variables.
Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than five)
Sixth field variable.
Etc., up to eight field variables per line.
Repeat this set of data
lines as often as necessary to define the dependence of the porous bulk moduli
on temperature and other predefined field
variables.
Data line
for cohesive elements
First
(and only) data line
. (Units of FL−2.)
Biot’s
coefficient then follows from the identity , where is given by the ELASTIC,
TYPE=TRACTION
option.