Defining a rotational body force

You can create a rotational body force load to define loads resulting from the rotation of the model.

You can specify angular velocity, rotary acceleration, or rotordynamic load. Abaqus defines the load by using the square of the angular velocity or by using the acceleration directly. In any case the load definition must include an axis of rotation, which is defined as follows:

  • If you are working in three-dimensional space, you define the location and direction of the axis by entering the global coordinates of two points.

  • If you are working in two-dimensional space, you specify the location of the axis by entering the coordinates of a point in the plane. The direction of the axis is always out of the plane.

  • If you are working in axisymmetric space, the axis is always in the location and direction of the positive global z-axis.

Note: You can define a rotary acceleration force only in two- or three-dimensional space.

See Also
Creating and modifying prescribed conditions
Understanding symbols that represent prescribed conditions
Using analytical expression fields
Creating expression fields
In Other Guides
Specifying Loads due to Rotation of the Model in Abaqus/Standard
  1. Display the rotational body force load editor using one of the following methods:
    • To create a new rotational body force load, follow the procedure outlined in Creating loads (Category: Mechanical; Types for Selected Step: Rotational body force).

      If you are working in two- or three-dimensional space, enter in the prompt area the required information concerning the location and, if applicable, the direction of the axis of rotation.

    • To edit an existing rotational body force load using menus or managers, see Editing step-dependent objects. To edit the region to which the load is applied, see Editing the region to which a prescribed condition is applied.

      If you are editing a load in the step in which it was created, an Edit ( ) button appears next to each point you specified in the load editor. Click if you want to change the coordinates that determine the location and, if applicable, direction of the axis of rotation. (This option applies only if you are working in two- or three-dimensional space.)

  2. Select the force type of your choice:
    • Toggle Centrifugal if you want to define a centrifugal force.
    • Toggle Rotary acceleration if you want to define a rotary acceleration force.
    • Toggle Rotordynamic load if you want to define a rotordynamic load.
  3. 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 body.
    • 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 The Analytical Field toolset for more information.)
  4. In the text field that appears, enter the appropriate value:
    • If you are defining a centrifugal force, enter the angular velocity in radians/time.
    • If you are defining a rotary acceleration force, enter the rotary acceleration in radians/time2.
    • If you are defining a rotordynamic load, enter the rotordynamic load in radians/time.
  5. 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 The Amplitude toolset for more information.)

    For centrifugal loading, the amplitude is applied to the calculated load, not the angular velocity.

  6. Click OK to save your data and to exit the editor.