ABAQUS Volume II: I–Z - Manual (Page 266)

*PIPE-SOIL STIFFNESS
TYPE
Set TYPE=LINEAR (default) to define a linear constitutive model.
Set TYPE=NONLINEAR to define a nonlinear constitutive model.
Set TYPE=CLAY to define a constitutive model using the ASCE formulae for clay. This
parameter must be used in conjunction with the DIRECTION parameter.
Set TYPE=SAND to define a constitutive model using the ASCE formulae for sand. This
parameter must be used in conjunction with the DIRECTION parameter.
Set TYPE=USER to indicate the constitutive behavior is defined in user subroutine UMAT.
The following optional parameters can be used only in combination with TYPE=USER:
PROPERTIES
Set this parameter equal to the number of property values needed as data in user subroutine UMAT.
The default is PROPERTIES=0.
VARIABLES
Set this parameter equal to the number of solution-dependent variables that must be stored for the
material calculations in user subroutine UMAT. The default is VARIABLES=1.
Data lines to define linear constitutive behavior (TYPE=LINEAR):
First line:
1. Interaction stiffness (force per relative displacement) corresponding to positive relative
displacements, .
2. Interaction stiffness (force per relative displacement) corresponding to negative relative
displacements, . The default is .
3. Temperature.
4. First field variable.
5. Second field variable.
6. Etc., up to five field variables.
Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than five):
1. Sixth field variable.
2. Etc., up to eight field variables per line.
Repeat this set of data lines as often as necessary to define the stiffness as a function of temperature
and other predefined field variables.
Data lines to define nonlinear constitutive behavior (TYPE=NONLINEAR):
First line:
1. Force per unit length along pipeline.
2. Relative displacement.
16.10–2
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