You can create a moment load to define rotation at a vertex or node.
To create or edit a moment:
Display the moment load editor using one of the following methods:
To create a new moment load, follow the procedure outlined in “Creating loads,” Section 16.8.1 (Category: Mechanical; Types for Selected Step: Moment).
To edit an existing moment load using menus or managers, see “Editing step-dependent objects,” Section 3.4.13. To edit the region to which the load is applied, see “Editing the region to which a prescribed condition is applied,” Section 16.8.4.
Click the arrow to the right of the Distribution field, and select the option of your choice from the list that appears:
Select Uniform to define a load that is uniform over the region.
Select an analytical field to define a spatially varying load. Only analytical fields that are valid for this load type are displayed in the selection list. Alternatively, you can click 
to create a new analytical field. (See Chapter 58, “The Analytical Field toolset,” for more information.)
In the CM1, CM2, and CM3 text fields, enter the components of the moment about each axis (units FL).
If you leave a text field blank, a moment of zero is assigned to that direction automatically. However, you must enter at least one nonzero component in the editor to define the load.
If desired, click the arrow to the right of the Amplitude field, and select the amplitude of your choice from the list that appears. Alternatively, you can click 
to create a new amplitude. (See Chapter 57, “The Amplitude toolset,” for more information.)
If desired, toggle on Follow nodal rotation to make the direction of the load rotate with the rotation at this node.
Follow nodal rotation affects only nodes that have rotational degrees of freedom and steps in which the Nlgeom setting is turned on.
If you want to change the coordinate system (CSYS) for the moment, click 
and use one of the following methods:
Select an existing datum coordinate system in the viewport.
Select an existing datum coordinate system by name.
From the prompt area, click Datum CSYS List to display a list of datum coordinate systems.
Select a name from the list, and click OK.
Note: You should not apply a moment load at the origin of a cylindrical coordinate system; doing so would make the radial and tangential loads indeterminate.
Click Use Global CSYS from the prompt area to revert to the global coordinate system.
Click OK to save your data and to exit the editor.
