*SURFACE BEHAVIOR
ABAQUS AnalysisUser ’sManual, for a discussion of the default penalty stiffness. You can specify
or modify the penalty stiffness on the data line.
Optional parameters:
NO SEPARATION
Include this parameter to prevent any separation of the two surfaces once contact has been
established.
PRESSURE-OVERCLOSURE
Use this parameter to choose a contact pressure-overclosurerelationship other than the default hard
contact.
Set PRESSURE-OVERCLOSURE=HARD (default) to choose a pressure-overclosure
relationship withoutphysical softening. Notethat some numerical softening will occur if a penalty
or augmented Lagrange constraint enforcement method is us ed.
Set PRESSURE-OVERCLOSURE=EXPONENTIAL to define an exponential pressure-
overclosure relationship.
Set PRESSURE-OVERCLOSURE=LINEAR to define a linear pressure-overclosure
relationship.
Set PRESSURE-OVERCLOSURE=SCALE FACTORto define a piecewise linear pressure-
overclosurerelationship based on scaling the default contact stiffness. This option is available only
for the general contact algorithm in ABAQUS/Explicit.
Set PRESSURE-OVERCLOSURE=TABULAR to define a piecewise linear pressure-
overclosure relationship in tabular form.
If a contactarea is not defined, such as may occur for node-based surfaces or for GAP- or ITT-
typecontact elements, “pressure” should be interpreted as force. Forcontact withthree-dimensional
beams or trusses, “pressure” should be interpreted as force per unit length.
When used to modify the default surface behavior, the PRESSURE-OVERCLOSURE
parameter cannot be used with the NO SEPARATION parameter in an ABAQUS/Standard
analysis.
Optional data line for AUGMENTED LAGRANGEand PENALTY:
First (and only) line:
1. User-defined penalty stiffness. If this field is left blank, the penalty stiffness has the default
value or is multiplied by the scale factor given in the third field of the data line.
2. Clearanceat which the contact pressure is zero. Thedefault is zero.
3. Scalefactor for the default penalty stiffness or for the penalty stiffness if specified in the first
field of the data line. The default is one.
18.47–2
ABAQUS Version 6.1 Module: ID:
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