The contact detection tool identifies potential contact pairs in a model using an array of user-defined parameters. Select Interaction
Find contact pairs or ConstraintFind contact pairs from the main menu, then enter the contact detection parameters. You can specify parameters in the following areas:
General search options indicate the range in which you want Abaqus/CAE to look for contact pair candidates. You can specify which areas of the model include contact pairs, as well as the estimated distance between surfaces that will require interaction or constraint definitions.
To specify general search options:
From the main menu, select either InteractionFind contact pairs or ConstraintFind contact pairs.
Tip:
You can also find contact pairs using the 
tool in the Interaction module toolbox.
Abaqus/CAE displays the contact detection dialog box.
Display the Search Options tabbed page if it is not visible already.
Specify the Search domain:
Select Whole model to include every instance in the current model.
Select Instance to include only specified part instances and child part instances. Use the following procedure to specify the instances:
Click 
.
Select the instances from the viewport (for information on selecting instances, see Chapter 6, “Selecting objects within the viewport”).
After you have selected all of the desired instances, click Done in the prompt area.
Select Displayed entities to include only those portions of the model that are currently displayed in the viewport. You can use the assembly display options and display groups to control the display of the model. For details, see “Controlling instance visibility,” Section 76.14, and Chapter 78, “Using display groups to display subsets of your model.”
Enter the maximum distance between potential contact pair surfaces in the Include pairs within separation tolerance field. For tips on selecting a separation tolerance, see “Choosing a separation tolerance and extension angle” in “Tips for using the contact detection tool,” Section 15.6.4.
By default, Abaqus/CAE extends surface definitions to any faces (for geometry) or facets (for meshed models) within 20° of the surfaces detected by the search. You can adjust this angle by changing the value in the Extend each surface found by angle field. To prevent the extension of surface definitions, toggle off Extend each surface found by angle. For further details on how Abaqus/CAE extends surfaces, see “Additional criteria for defining contact pairs” in “The contact detection algorithm,” Section 15.6.2.
By default, Abaqus/CAE creates contact pairs from surfaces located on different part instances or model instances. To search for contact pairs involving different regions on the same part instance or model instance or to search for potential self-contact interactions, toggle on Include pairs with surfaces on the same instance. For details, see “Defining contact within the same instance and self-contact” in “The contact detection algorithm,” Section 15.6.2.
In addition to creating contact pair interactions, the automatic contact detection tool also creates named surfaces for each surface involved in a contact pair (see “Default interaction and constraint parameters,” Section 15.6.3). The Names tabbed page provides some options for tuning this surface creation behavior.
To specify naming options:
From the main menu, select either InteractionFind contact pairs or ConstraintFind contact pairs.
Tip:
You can also find contact pairs using the tool in the Interaction module toolbox.
Abaqus/CAE displays the contact detection dialog box.
Display the Names tabbed page.
In the Name prefix field, enter the prefix that will be used when naming each contact pair and surface (as discussed in “Default interaction and constraint parameters,” Section 15.6.3).
To prevent the creation of named surfaces, toggle off Name each surface found. This option will not affect the creation of contact pairs.
The Create additional named surfaces containing field allows you to create additional composite surfaces:
To create a single named surface composed of all contact pair surfaces acting as a master surface, toggle on All master. Any master surfaces from preexisting contact pairs are also included in the created composite surface.
To create a single named surface composed of all contact pair surfaces acting as a slave surface, toggle on All slave. Any slave surfaces from preexisting contact pairs are also included in the created composite surface.
To create a single named surface composed of all surfaces involved in contact pair definitions, toggle on All. Any surfaces from preexisting contact pairs are also included in the created composite surface.
The Entities tabbed page allows you to control the types of geometry and elements that are included in a search. You can use these options to ignore certain features of a model or part instance that are not essential to contact interactions or constraints; for example, a layer of membrane elements on the outside of a solid body. Removing features from a search may also improve performance; for example, if all the contacting faces in a complex model are planar, removing cylindrical and spline-based features from the contact pair search may lead to faster search times. In general, the default entity options provide acceptable performance and should be modified only if a search is taking an excessively long time to complete.
To specify entity options:
From the main menu, select either InteractionFind contact pairs or ConstraintFind contact pairs.
Tip:
You can also find contact pairs using the tool in the Interaction module toolbox.
Abaqus/CAE displays the contact detection dialog box.
Display the Entities tabbed page.
By default, Abaqus/CAE factors in shell thickness and offset properties when calculating the separation between shell entities. To ignore shell section properties and calculate separations based solely on the geometric representation of shell entities in a model, toggle off Account for shell thickness and offset during search.
When performing a search of geometry, toggle the following features in the Search the following geometric entities field to include or exclude them from the search domain:
Planar refers to all flat faces in a model. These features are toggled on by default.
Cylindrical/Spherical/Toroidal refers to curved faces in a model that were generated by extruding or revolving a straight, circular, or elliptical line. These features are toggled on by default.
Spline-based refers to irregularly curved faces in a model that were generated from spline lines or paths (see “Sketching splines,” Section 20.10.10 for more information). These features are toggled on by default.
When performing a search of meshed geometry, toggle the following element types in the Search the following mesh entities field to include or exclude them from the search domain:
Solid refers to faces on solid continuum elements. These elements are toggled on by default.
Shell refers to faces on shell elements. These elements are toggled on by default.
Membrane refers to faces on membrane or surface elements. These elements are toggled off by default.
Contact detection rules allow you to specify a set of conditional options that determine the default settings assigned to detected contact pairs. You can always change the contact pair settings after they are detected, but specifying rules before a search allows you to define appropriate contact pairs quickly according to your particular modeling intent. The rules are applied when Abaqus/CAE performs a search for contact pair candidates. For more information about contact pair default settings, see “Default interaction and constraint parameters,” Section 15.6.3.
To specify rules for default contact pair settings:
From the main menu, select either InteractionFind contact pairs or ConstraintFind contact pairs.
Tip:
You can also find contact pairs using the tool in the Interaction module toolbox.
Abaqus/CAE displays the contact detection dialog box.
Display the Rules tabbed page.
Click 
.
Abaqus/CAE displays the Edit Rules dialog box.
To create tie constraints for all contact pairs whose surfaces lie within a particular tolerance, toggle on Use tie constraints when the separation value does not exceed and enter the tolerance in the field provided. This rule is disabled by default.
To set the position tolerance on tie constraints equal to the surface separation reported by the contact detection tool, toggle on Set tie position tolerance to separation value when nonzero. This rule is disabled by default. For more information about position tolerances for tie constraints, see “Mesh tie constraints,” Section 35.3.1 of the Abaqus Analysis User's Guide.
To set the surface adjustment setting on contact interactions equal to the surface separation reported by the contact detection tool, toggle on Adjust separated interactions by the separation value. This rule is disabled by default. For more information about surface adjustment options, see “Adjusting initial surface positions and specifying initial clearances in Abaqus/Standard contact pairs,” Section 36.3.5 of the Abaqus Analysis User's Guide.
To move any overclosed slave nodes in a contact interaction directly onto the master surface, toggle on Adjust interactions to remove overclosure. The adjustment is performed during the analysis. This rule is enabled by default. For more information about surface adjustment options, see “Adjusting initial surface positions and specifying initial clearances in Abaqus/Standard contact pairs,” Section 36.3.5 of the Abaqus Analysis User's Guide.
Click OK.
The advanced search options provide an added level of control over the search range and the creation of contact pair surfaces. The general search options are sufficient in most cases; however, you may want to use the advanced options to account for unique modeling conditions. See “Tips for using the contact detection tool,” Section 15.6.4, for a discussion of various modeling conditions and the recommended search techniques.
To specify advanced search options:
From the main menu, select either InteractionFind contact pairs or ConstraintFind contact pairs.
Tip:
You can also find contact pairs using the tool in the Interaction module toolbox.
Abaqus/CAE displays the contact detection dialog box.
Display the Advanced tabbed page.
By default, Abaqus/CAE merges any contact pairs whose adjacent surfaces lie within 20° of each other (for details on this calculation, see “Additional criteria for defining contact pairs” in “The contact detection algorithm,” Section 15.6.2). You can adjust this angle by changing the value in the Merge pairs when surfaces are within angle field. To prevent the merging of adjacent contact pairs, toggle off Merge pairs when surfaces are within angle.
By default, Abaqus/CAE includes overclosed and intersecting surfaces when searching for contact pairs. To ignore overclosed surfaces, toggle off Include overclosed surfaces. For details on how the automatic contact detection tool interprets overclosed surfaces, see “Detection of overclosed surfaces” in “The contact detection algorithm,” Section 15.6.2.
By default, Abaqus/CAE does not create a contact pair candidate if two surfaces are laterally offset from each other (i.e., the surface normals from either surface never intersect the opposite surface). To include these surfaces in the contact pair candidates table, toggle on Include opposing surfaces that do not overlap. Such surfaces must still meet the separation and orientation requirements for the search. See “Additional criteria for defining contact pairs” in “The contact detection algorithm,” Section 15.6.2, for further discussion of this option.
If your search includes part instances that have been meshed from geometry, indicate how Abaqus/CAE should interpret these instances during the search:
To treat the instances as geometry, select Geometry. Abaqus/CAE uses the Geometry option by default.
To treat the instances as element meshes, select Mesh.
Tip: To detect contact between geometry and mesh instances, first mesh the geometry, then perform a mesh-based search.
To save the current search parameters as defaults for future sessions of Abaqus/CAE, click 
(for more information, see “Saving the search parameters” in “Tips for using the contact detection tool,” Section 15.6.4). To reset saved search parameters to the original defaults, click 
.