Gap element library | |||||||
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ProductsAbaqus/Standard
Element types
Stress/displacement elements
- GAPUNI
Unidirectional gap between two nodes
- GAPCYL
Cylindrical gap between two nodes
- GAPSPHER
Spherical gap between two nodes
Active degrees of freedom
1, 2, 3
Additional solution variables
Three additional variables relating to the contact and friction forces.
Coupled temperature-displacement element
- GAPUNIT
Unidirectional gap and thermal interactions between two nodes
Active degrees of freedom
1, 2, 3, 11
Additional solution variables
Three additional variables relating to the contact and friction forces.
Heat transfer element
- DGAP
Thermal interactions between two nodes
Active degrees of freedom
11
Additional solution variables
None.
Nodal coordinates required
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
Element property definition
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
Element-based loading
None.
Element output
- 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.
Nodes associated with the element
Two nodes: the ends of the gap.