This option is used to modify the default contact pressure-overclosure relationship in a mechanical contact analysis. Mechanical interactions normal to the surfaces are influenced by this option. It must be used in conjunction with the *SURFACE INTERACTION option or in an ABAQUS/Standard analysis with the *GAP option or the *INTERFACE option.
Products: ABAQUS/Standard ABAQUS/Explicit
Type: Model data in ABAQUS/Standard; History data in ABAQUS/Explicit
Level: Part Part Instance Assembly Model in ABAQUS/Standard; Step in ABAQUS/Explicit
This parameter applies only to ABAQUS/Standard analyses. Include this parameter to choose the augmented Lagrangian enforcement of the contact constraint.
Use this parameter to choose the type of contact pressure-overclosure relationship.
Set PRESSURE-OVERCLOSURE=HARD (default) to choose contact behavior without softening.
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=TABULAR to define a piecewise linear pressure-overclosure relationship in tabular form.
If a contact area is not defined, such as may occur for node-based surfaces or for GAP- or ITT-type contact elements, “pressure” should be interpreted as force. For contact with three-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.
Include this parameter to prevent any separation of the two surfaces once contact has been established.
First (and only) line:
Penalty stiffness. This value must be positive. If the field is left blank, the penalty stiffness value will be calculated automatically.
Clearance at which the contact pressure is zero. The default is zero.
First (and only) line:
Clearance at which the contact pressure is zero, 
(see Figure 18.47–1).
Pressure at zero clearance, 
.
The following data item is available only in ABAQUS/Explicit analyses:
Value of the maximum stiffness 
. When using penalty contact, large stiffness values obtained from the exponential law may significantly lower the stable time increment size. Choose a suitable maximum stiffness to mitigate this effect (see Figure 18.47–1). By default, is set equal to infinity for kinematic contact and the default penalty stiffness for penalty contact.
First (and only) line:
Slope of the pressure-overclosure curve. This value must be positive.
First line:
Pressure.
Overclosure.
Repeat this data line in ascending order of overclosure value as often as necessary to define the overclosure as a function of pressure. A minimum of two data lines are required. The pressure-overclosure relationship is extrapolated beyond the last overclosure point by continuing the same slope (see Figure 18.47–2).
