Product: ABAQUS/Standard
| GAPUNI | Unidirectional gap between two nodes |
| GAPCYL | Cylindrical gap between two nodes |
| GAPSPHER | Spherical gap between two nodes |
For DGAP elements, and for GAPUNI and GAPUNIT if you specify the contact direction 
, the nodal coordinates are not used in the contact calculations; however, it is useful to define the coordinates of the two nodes for plotting purposes.
GAPCYL and GAPSPHER: X, Y, Z
You can specify the initial clearance, the contact direction (normal to the interface), and the contact area.
For GAPUNI, GAPUNIT, and DGAP elements, a negative clearance indicates an initial overclosure.
For GAPCYL and GAPSPHER elements, specify the maximum separation as a positive number or the minimum separation as a negative number.
| Input File Usage: | *GAP |
S11 | Pressure transmitted between the surfaces. The pressure is defined as the force divided by the user-specified area. |
S12 | First frictional shear stress normal to the gap direction. |
S13 | Second frictional shear stress normal to the gap direction. |
E11 | Current opening h of the gap element. |
E12 | Relative displacement (“slip”) in the first direction orthogonal to the contact direction. |
E13 | Relative displacement (“slip”) in the second direction orthogonal to the contact direction. |
Available for elements with temperature degrees of freedom.
HFL1 | Heat flux across the interface in the contact direction. |
The increments of shear slip are the relative displacement increments projected onto the two local directions that are orthogonal to the contact direction.
In two-dimensional or axisymmetric models when the contact direction is along the first axis (X or r), the active slip direction is E13 and the active shear stress is S13. In any other two-dimensional or axisymmetric case, the active slip direction is E12 and the active shear stress is S12.