Defining contacting surfaces in an Abaqus/Standard analysis
Required parameters
- INTERACTION
-
Set this parameter equal to the name of the SURFACE INTERACTION property definition associated with the contact pair being defined.
Optional parameters
- ADJUST
-
Set this parameter equal to a node set label or a value to adjust the initial positions of the surfaces specified in this option. These adjustments are made at the start of the analysis and do not create any strain.
Set ADJUST=YES and use the POSITION TOLERANCE parameter to adjust the initial positions of the surfaces specified in this option. These adjustments are made at the start of the analysis and do not create any strain.
Alternatively, for SMALL SLIDING contact or TIED contact, set ADJUST=NO and use the POSITION TOLERANCE parameter to control which secondary nodes are considered initially in contact or tied. In these cases, initial positions of the surfaces are not adjusted, and offset distances are considered for penetration calculations of the respective secondary nodes such that the initial penetration is zero.
This parameter is required for TIED contact.
If this parameter is omitted, overclosures are treated as interference fits.
- EXTENSION ZONE
-
Set this parameter equal to a fraction of the end segment or facet edge length by which the main surface is to be extended to avoid numerical roundoff errors associated with contact modeling. The value given must lie between 0.0 and 0.2. The default is 0.1. This parameter affects only node-to-surface contact.
- GEOMETRIC CORRECTION
-
Set this parameter equal to the name of the surface smoothing property defined by SURFACE SMOOTHING. This parameter affects only surface-to-surface contact.
- HCRIT
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Set this parameter equal to the distance by which a point on the secondary surface must penetrate the main surface before Abaqus/Standard abandons the current increment and tries again with a smaller increment. The default value of HCRIT is half of the length of a characteristic element face on the secondary surface. This parameter does not apply to contact pairs that use the finite-sliding, surface-to-surface contact formulation.
- MIDFACE NODES
-
Set MIDFACE NODES=YES to automatically convert most three-dimensional second-order element types with no midface node (serendipity elements) that form a secondary surface of a surface-to-surface contact pair into elements with a midface node.
Set MIDFACE NODES=NO (default) to avoid adding midface nodes to elements underlying the secondary surface of a surface-to-surface contact pair.
This parameter can be used only with surface-to-surface contact pairs. Abaqus/Standard automatically converts most serendipity elements that form a secondary surface of a node-to-surface contact pair into elements with a midface node.
- MINIMUM DISTANCE
-
Set MINIMUM DISTANCE=YES (default) to automatically activate localized contact damping when nearby surfaces are initially touching at only a single point.
Set MINIMUM DISTANCE=NO to forgo this automatic localized damping.
This parameter can be used only with the finite-sliding, surface-to-surface contact formulation.
- NO THICKNESS
-
Include this parameter to ignore surface thickness effects in the contact calculations. This parameter affects only contact formulations that account for surface thickness by default (it does not affect finite-sliding, node-to-surface contact).
- POSITION TOLERANCE
-
This parameter is applicable only if ADJUST=YES or ADJUST=NO.
Set this parameter equal to the upper bound of the initial gap distance for which secondary nodes are to be adjusted if ADJUST=YES. If this parameter is omitted, Abaqus/Standard adjusts only those secondary nodes that are penetrating the main surface.
Set this parameter equal to the upper bound of the initial gap distance for which secondary nodes are considered initially in contact or tied if ADJUST=NO. Initial positions of these secondary nodes are not adjusted automatically. Instead, offset distances for use in penetration calculations for these nodes are generated internally such that the initial penetration is zero with consideration of the offset distance. These offsets remain in effect throughout the simulation.
- SMALL SLIDING
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Include this parameter to indicate that the small-sliding contact formulation, rather than the finite-sliding contact formulation, should be used. This parameter is not allowed with self-contact.
- SMOOTH
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Set this parameter equal to the degree of smoothing used for element-based main surfaces in the finite-sliding, node-to-surface contact formulation. The value given must lie between 0.0 and 0.5. The default is 0.2. This parameter does not affect contact pairs with analytical rigid surfaces or contact formulations other than the finite-sliding, node-to-surface contact formulation.
- SLIDING TRANSITION
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Set SLIDING TRANSITION=ELEMENT ORDER SMOOTHING to have smoothing of the nodal force redistribution upon sliding be of the same order as the elements underlying the secondary surface.
Set SLIDING TRANSITION=LINEAR SMOOTHING to have linear smoothing of the nodal force redistribution upon sliding.
Set SLIDING TRANSITION=QUADRATIC SMOOTHING to have quadratic smoothing of the nodal force redistribution upon sliding.
This parameter can be used only with the surface-to-surface contact formulation.
- SUPPLEMENTARY CONSTRAINTS
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Set SUPPLEMENTARY CONSTRAINTS=SELECTIVE (default) to use a selective scheme of supplementary constraints.
Set SUPPLEMENTARY CONSTRAINTS=YES to add the supplementary contact constraints when applicable.
Set SUPPLEMENTARY CONSTRAINTS=NO to forgo the supplementary contact constraints.
- TIED
-
Include this parameter to indicate that the surfaces of this CONTACT PAIR are to be “tied” together for the duration of the simulation. The ADJUST parameter is required when the TIED parameter is used. This parameter is not allowed with self-contact.
- TRACKING
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This parameter controls which contact tracking algorithm is used for finite-sliding, surface-to-surface contact; it has no effect on contact pairs that use other formulations.
Set TRACKING=PATH (default) to invoke a path-based contact tracking algorithm for finite-sliding, surface-to-surface contact.
Set TRACKING=STATE to invoke a state-based contact tracking algorithm for finite-sliding, surface-to-surface contact.
- TYPE
-
Set TYPE=NODE TO SURFACE (default) to have the contact constraint coefficients generated according to the interpolation functions at the point where the secondary node projects onto the main surface.
Set TYPE=SURFACE TO SURFACE to have the contact constraint coefficients generated such that stress accuracy is optimized for the specified surface type pairings. This parameter setting will be ignored for contact pairs that include a node-based surface.
Data lines to define the surfaces and node sets forming the contact pairs
- First line
-
The secondary surface name.
The main surface name. If the main surface name is omitted or is the same as the secondary surface name, Abaqus/Standard assumes that self-contact is defined.
Optional orientation name to specify the local tangent directions on the secondary surface.
Optional orientation name to specify the local tangent directions on the main surface.
Repeat this data line as often as necessary to define all of the surfaces or node sets forming the contact pairs. Each data line defines a pair of surfaces or a node set and a surface that may interact with one another.