Area Loads- Rotate (Asolid)

Form: Area Rotate Loads

The Assign menu > Area Loads > Rotate (Asolid) command is used to apply centrifugal force to an object . Each object is assumed to rotate about its own axis of symmetry at a constant angular velocity. The angular velocity creates a load on the object that is proportional to its mass, distance from the axis of rotation and the square of the angular velocity. This load acts in the positive radial direction and is apportioned to each joint of the object. No Rotate Load will be produced by an object with zero mass density.

Select the area object(s) to be applied centrifugal force (i.e., an area rotate load).
Use the Assign menu > Area Loads > Rotate (Asolid) command to access the Area Rotate Load form.
- Load Pattern Name. Select the load pattern to which this rotate load is being added. Alternatively, click the + (plus symbol) beside the drop-down list to access the Define Load Patterns form; use the form to define a load pattern that will then be available in the drop-down list.
- Angular Velocity. Type a value for the angular velocity in cycles/seconds in the edit box.
- Options. Choose from one of the following options to specify how the load is to be applied:
- - Add to Existing Loads: Adds the specified centrifugal force to the area object. If one or more centrifugal force assignments have already been made, this option increases the existing load, assuming that a positive load is being specified.
  - Replace Existing Loads: Replaces the currently specified centrifugal force, if any, with the new load. If no assignment exists, the new assignment is still made. This is the default option.
  - Delete Existing Loads: Deletes any and all centrifugal force load assignments made to the selected area object(s). When this option is selected, the items in the Angular Velocity area of the form are ignored when the OK button is clicked.

Tip: When performing a time history analysis, it does not make sense to use the load pattern assigned this rotate load unless the load pattern is applied using a very slow time variation because the rotate load assigned here assumes a constant rate of rotation.

The window will refresh with a graphical representation of the load assigned on the selected members. If necessary, use the Assign menu > Clear Assigns command to remove the display of the assigned load.