Assigning Contact Properties
The default contact property model in Abaqus/Standard assumes “hard” contact in the normal direction, no friction, no thermal interactions, etc. You can assign a nondefault contact property definition (surface interaction) to specified regions of the general contact domain. These regions are identified with surface names or material names. For example, contact property ContProp_A can be assigned to the combination of surface Surf_1 and the surface whose underlying elements have a section assignment with material Rubber. Surfaces associated with Surf_1 and Rubber can span multiple parts.
Contact properties for general contact in Abaqus/Standard are assigned at the beginning of the analysis and cannot be modified across steps, with an exception for changes to the friction model, as discussed below.
The surface names used to specify the regions where nondefault contact properties should be assigned do not have to correspond to the surface names used to specify the general contact domain. In many cases the contact interaction will be defined for a large domain, while nondefault contact properties will be assigned to a subset of this domain. Any contact property assignments for regions that fall outside of the general contact domain will be ignored. The last assignment will take precedence if the specified regions overlap.
Input File Usage
CONTACT PROPERTY ASSIGNMENT surface_1 or material_1, surface_2 or material_2, interaction_property_name, SURFACE (default) or MATERIAL, SURFACE (default) or MATERIAL
This option must be used in conjunction with the CONTACT option and should appear at most once; the data line can be repeated as often as necessary to assign contact properties to different regions.
The fourth and fifth entries indicate whether the first and second entries, respectively, refer to surface or material names. If omitted, Abaqus assumes that a surface name is used.
If the first entry is omitted, a default surface that encompasses the entire general contact domain is assumed. If the second entry is omitted or is the same as the first entry, contact between the first named or implied surface and itself is assumed. Surfaces can span multiple unattached bodies, so self-contact of a surface is not limited to contact of a single body with itself. If the interaction property name is omitted, the unnamed set of default contact properties in Abaqus/Standard is assumed. If an interaction property name is specified, it must also appear as the value of the NAME parameter on a SURFACE INTERACTION option in the model portion of the input file.
Abaqus/CAE Usage
Use the following options to assign a global contact property to the entire general contact domain:
Interaction module: Create Interaction: General contact (Standard): Contact Properties: Global property assignment: interaction_property_name
Use the following options to assign contact properties to individual surface pairs:
Interaction module: Create Interaction: General contact (Standard): Contact Properties: Individual property assignments: Edit: select the combinations of surfaces and materials and the contact property in the columns on the left, and click the arrows in the middle to transfer them to the list of contact property assignments
In Abaqus/CAE you must assign a global contact property; Abaqus/CAE does not assume a default contact interaction property. Contact properties assigned to individual surface pairs override the global assignment.
Changing Friction Properties during an Analysis
The friction properties associated with a given named surface interaction definition can be modified in any particular step of an Abaqus/Standard analysis, as discussed in Changing Friction Properties during an Abaqus/Standard Analysis.
Example
The following contact property assignments are specified below as model data in a general contact analysis:
-
a global assignment of
contProp1to the entire general contact domain; -
a local assignment of
contProp2to self-contact forsurf1; -
a local assignment of the default Abaqus contact property to contact between
surf2andsurf3; and -
a local assignment of
contProp3to contact between the entire contact domain andsurf4. The friction coefficient forcontProp3is reset from the initial value of 0.20 to 0.05 in the second step.
SURFACE INTERACTION, NAME=contProp1 FRICTION 0.1 SURFACE INTERACTION, NAME=contProp2 FRICTION 0.15 SURFACE INTERACTION, NAME=contProp3 FRICTION 0.20 CONTACT CONTACT INCLUSIONS, ALL EXTERIOR CONTACT PROPERTY ASSIGNMENT , , contProp1 surf1, surf1, contProp2 surf2, surf3, , surf4, contProp3 … STEP Step1 STATIC … END STEP STEP Step2 STATIC … CHANGE FRICTION, INTERACTION NAME=contProp3 FRICTION 0.05 END STEP