Specifying surface property assignments for general contact

Attributes for a general contact interaction, such as surface properties, are specified independently of the contact domain in the Attribute Assignments portion of the interaction editor. For a brief overview of general contact, see Understanding interactions. For a more detailed discussion, see Surface properties for general contact in Abaqus/Standard, and Assigning surface properties for general contact in Abaqus/Explicit.

You can specify the following surface properties in a general contact interaction:

  • Surface thickness assignments. Assign nondefault surface thicknesses to shell or membrane surfaces.

  • Shell/Membrane offset assignments. Assign the surface offset to define the distance (as a fraction of the surface thickness) from the midsurface to the reference surface.

  • Surface smoothing assignments. Assign nondefault contact smoothing to model surfaces. Contact smoothing improves the contact stress and pressure accuracy for curved surfaces (see Smoothing contact surfaces in Abaqus/Standard).

  • Feature edge criteria assignments. Control the feature edges to be included in the general contact domain. Feature edges of a model include shell perimeter edges and geometric feature edges. Modeling of edge-to-edge contact is not allowed for Abaqus/Standard analyses.

This task shows you how to:

Related Topics
Interaction editors
Defining general contact
In Other Guides
Surface properties for general contact in Abaqus/Standard
Assigning surface properties for general contact in Abaqus/Explicit

Specify surface thickness assignments

  1. Display the general contact interaction editor using one of the following methods:

    • To create a new general contact interaction, follow the instructions in Defining general contact.

    • To edit an existing general contact interaction, select InteractionEditinteraction name from the main menu bar.

  2. Click the Surface Properties tab in the Attribute Assignments portion of the interaction editor.

    The surface thickness can be modified only for surfaces defined on shells and membranes.

  3. Click next to Surface thickness assignments.

    The Edit Surface Thickness Assignments dialog box appears. By default, when you select a surface from the list or the table, Abaqus/CAE highlights the surface in the viewport; however, highlighting does not apply for (Global). You can toggle off Highlight selected regions at the bottom of the dialog box to turn off selection highlighting.

  4. Select one or more surfaces from the list of existing surfaces in the column on the left. Select (Global) to assign the shell/membrane thickness to the entire contact domain.

    Tip: You can click to define a new surface and add it to the list. See Creating surfaces, for instructions on defining surfaces.

  5. Click the arrows in the middle of the dialog box to transfer your selections to the list of shell/membrane thickness assignments.

    The table on the right side of the dialog box is updated to reflect your selections.

  6. Specify the thickness for each surface in the middle column of the Surface Thickness Assignments table.

    • Enter the word ORIGINAL to set the shell/membrane thickness equal to the original shell or membrane thickness (the default);

    • enter the word THINNING to set the shell/membrane thickness equal to the current shell or membrane thickness (this option is available only in Abaqus/Explicit); or

    • specify a value for the shell/membrane thickness.

  7. Optionally, specify a scale factor for any of the shell/membrane thickness assignments in the last column of the Surface Thickness Assignments table.

  8. Repeat the above steps as needed to complete the shell/membrane thickness assignments. If you want to delete thickness assignments, select the rows and click .

    Note:

    The order of assignments may be relevant; when shell/membrane thickness assignments overlap, the last assignment will take precedence.

  9. Click OK to save your selections and to close the Edit Surface Thickness Assignments dialog box.

    The interaction editor reappears with updated information on the number of shell/membrane thickness assignments.

  10. Click OK to create the interaction and to close the editor.

Specify shell/membrane offset assignments

  1. Display the general contact interaction editor using one of the following methods:

    • To create a new general contact interaction, follow the instructions in Defining general contact.

    • To edit an existing general contact interaction, select InteractionEditinteraction name from the main menu bar.

  2. Click the Surface Properties tab in the Attribute Assignments portion of the interaction editor.

    The surface offset can be modified only for surfaces defined on shells and membranes.

  3. Click next to Shell/Membrane offset assignments.

    The Edit Shell/Membrane Offset Assignments dialog box appears. By default, when you select a surface from the list or the table, Abaqus/CAE highlights the surface in the viewport; however, highlighting does not apply for (Global). You can toggle off Highlight selected regions at the bottom of the dialog box to turn off selection highlighting.

  4. Select one or more surfaces from the list of existing surfaces in the column on the left. Select (Global) to assign the shell/membrane offset to the entire contact domain.

    Tip: You can click to define a new surface and add it to the list. See Creating surfaces, for instructions on defining surfaces.

  5. Click the arrows in the middle of the dialog box to transfer your selections to the list of shell/membrane offset assignments.

    The table on the right side of the dialog box is updated to reflect your selections.

  6. Specify the offset fraction for each surface in the second column of the Shell/Membrane Offset Assignments table. The offset fraction defines the distance (as a fraction of the thickness) from the midsurface to the reference surface.

    • Enter the word ORIGINAL to set the shell/membrane offset equal to the original shell or membrane offset (the default).

    • Enter SPOS to specify the top surface of the shell/membrane as the reference surface.

    • Enter SNEG to specify the bottom surface of the shell/membrane as the reference surface.

    • Specify a value between −0.5 (indicates the bottom surface of the shell/membrane) and 0.5 (indicates the top surface of the shell/membrane) for the offset fraction.

  7. Repeat the above steps as needed to complete the shell/membrane offset assignments. If you want to delete offset assignments, select the rows and click .

    Note:

    The order of assignments may be relevant; when shell/membrane offset assignments overlap, the last assignment will take precedence.

  8. Click OK to save your selections and to close the Edit Shell/Membrane Offset Assignments dialog box.

    The interaction editor reappears with updated information on the number of shell/membrane offset assignments.

  9. Click OK to create the interaction and to close the editor.

Specify surface smoothing assignments

  1. Display the general contact interaction editor using one of the following methods:

    • To create a new general contact interaction, follow the instructions in Defining general contact.

    • To edit an existing general contact interaction, select InteractionEditinteraction name from the main menu bar.

    In an Abaqus/Standard general contact interaction, surface smoothing assignments can be specified only in the initial step. In an Abaqus/Explicit general contact interaction, surface smoothing assignments can be specified or modified in any analysis step.

  2. Click the Surface Properties tab in the Attribute Assignments portion of the interaction editor.

  3. Click next to Surface smoothing assignments.

    The Edit Surface Smoothing Assignments dialog box appears. By default, when you select a surface from the list or the table, Abaqus/CAE highlights the surface in the viewport and displays the detected axis or center of curvature that will be used in the smoothing calculation. You can toggle off Highlight selected regions at the bottom of the dialog box to turn off selection highlighting.

  4. Toggle Automatically assign smoothing for geometric faces to determine whether Abaqus/CAE applies surface smoothing automatically to all appropriate surfaces in the general contact domain. This option is on by default for Abaqus/Standard general contact interactions and off by default for Abaqus/Explicit general contact interactions.

  5. Select one or more surfaces from the list of existing surfaces in the column on the left.

    Tip: You can click to define a new surface and add it to the list. See Creating surfaces, for instructions on defining surfaces.

  6. Click the arrows in the middle of the dialog box to transfer your selections to the list of surface smoothing assignments.

    The table on the right side of the dialog box is updated to reflect your selections.

  7. Specify the smoothing to apply to each surface in the second column of the Surface Smoothing Assignments table. The smoothing specified for these surfaces overrides the default global smoothing if it is applied.

    • Select REVOLUTION to apply circumferential smoothing to a curved surface that is symmetric about an axis of revolution (or a two-dimensional arc that is symmetric about a central point).

    • Select SPHERICAL to apply spherical smoothing to a curved surface that is symmetric about a central point.

    • Select TOROIDAL to apply toroidal smoothing to a curved surface that is a circular arc symmetric about an axis of revolution.

    • Select NONE to prevent smoothing from being applied to the specified surface.

  8. Repeat the above steps as needed to complete the surface smoothing assignments. If you want to delete smoothing assignments, select the rows and click .

    Note:

    The order of assignments may be relevant; when smoothing assignments overlap, the last assignment will take precedence.

  9. Click OK to save your selections and to close the Edit Surface Smoothing Assignments dialog box.

    The interaction editor reappears with updated information on the number of surface smoothing assignments.

  10. Click OK to create the interaction and to close the editor.

Specify feature edge criteria assignments

  1. Display the general contact interaction editor using one of the following methods:

    • To create a new general contact interaction, follow the instructions in Defining general contact.

    • To edit an existing general contact interaction, select InteractionEditinteraction name from the main menu bar.

  2. Click the Surface Properties tab in the Attribute Assignments portion of the interaction editor.

  3. Click next to Feature edge criteria assignments.

    The Edit Feature Edge Criteria Assignments dialog box appears. By default, when you select a surface from the list or the table, Abaqus/CAE highlights the surface in the viewport; however, highlighting does not apply for (Global). You can toggle off Highlight selected regions at the bottom of the dialog box to turn off selection highlighting.

  4. Select one or more surfaces from the list of existing surfaces in the column on the left. Select (Global) to assign the surface feature to the entire contact domain.

    Tip: You can click to define a new surface and add it to the list. See Creating surfaces, for instructions on defining surfaces.

  5. Click the arrows in the middle of the dialog box to transfer your selections to the list of surface feature assignments.

    The table on the right side of the dialog box is updated to reflect your selections.

  6. Specify the feature edge criteria for each surface in the second column of the Surface Feature Assignments table by doing one of the following:

    • Enter the word PERIMETER to include only perimeter edges in the general contact domain.

    • Enter the word ALL to include all edges in the general contact domain (this option is available only for Abaqus/Explicit).

    • Enter the word PICKED to include in the general contact domain only edges that were explicitly selected as part of the surface definition (this option is available only for shell geometries and elements in Abaqus/Explicit).

    • Enter the word NONE to include no feature edges in the general contact domain.

    • Specify an angle in degrees to include perimeter edges and geometric edges with feature angles greater than or equal to the specified angle in the general contact domain. The specified value must be between 0° and 180°. For examples of how the feature angle is calculated for different edges, see Feature edges.

  7. Repeat the above steps as needed to complete the surface feature assignments. If you want to delete surface feature assignments, select the rows and click .

    Note:

    The order of assignments may be relevant; when surface feature assignments overlap, the last assignment will take precedence.

  8. Click OK to save your selections and to close the Edit Feature Edge Criteria Assignments dialog box.

    The interaction editor reappears with updated information on the number of feature edge criteria assignments.

  9. Click OK to create the interaction and to close the editor.