You use a Standard-Explicit co-simulation interaction to define the interface region and coupling schemes for an Abaqus/Standard to Abaqus/Explicit co-simulation. Select Interaction
Create from the main menu bar, and select the region for exchanging data. For more information, see Chapter 26, “Co-simulation.”
A Standard-Explicit co-simulation interaction can be created only in a general static, implicit dynamic, or explicit dynamic step. The interaction is valid only in the step in which it is created and is not propagated to subsequent steps. Only one Standard-Explicit co-simulation interaction can be active in a model.
To define a Standard-Explicit co-simulation interaction:
From the main menu bar, select InteractionCreate.
Tip:
You can also create a Standard-Explicit co-simulation interaction using the 
tool in the Interaction module toolbox.
In the Create Interaction dialog box that appears, do the following:
Name the interaction. For more information about naming objects, see “Using basic dialog box components,” Section 3.2.1.
Select the step in which the interaction will be created.
Select the Standard-Explicit co-simulation type of interaction.
Click Continue to close the Create Interaction dialog box.
In the prompt area, select one of the following for the co-simulation region type:
Select Surface if you want to select a surface.
Select Node Region if you want to select nodes.
Use one of the following methods to select the region:
Use an existing set or surface to define the region. On the right side of the prompt area, click Sets or Surfaces. Select an existing set or surface from the Region Selection dialog box that appears, and click Continue.
Note: The default selection method is based on the selection method you most recently employed. To revert to the other method, click Select in Viewport or Sets or Surfaces on the right side of the prompt area.
Use the mouse to select a region in the viewport. (For more information, see “Selecting objects within the current viewport,” Section 6.2.)
If the model contains a combination of mesh and geometry, click one of the following from the prompt area:
Click Geometry if you want to select the surface from a geometry region.
Click Mesh if you want to select the surface from a native or orphan mesh selection.
Choose the Incrementation control method. The same incrementation method must be used in the Abaqus/Standard and Abaqus/Explicit analyses. This option is not available in a static general step.
Choose Allow subcycling to allow the Abaqus/Standard increment size to differ from those in Abaqus/Explicit; fields will be exchanged as needed.
Choose Lock time steps to force Abaqus/Standard to match the increment size of Abaqus/Explicit; fields will be exchanged at each of the shared increments.
Choose the Coupling step period. In Abaqus/Standard analyses, Abaqus always uses the next increment size as the suggested coupling step size.
Choose Determined by analysis to have Abaqus use the next increment size as the suggested coupling step size.
Choose Specified, and enter a value for the coupling step size (available only in an Abaqus/Explicit analysis).
Click OK to create the interaction and to close the editor.
