Applying Uniform Base Motion for a Modal Time History Study

To apply uniform base motion for a modal time history study:

  1. Right-click the Load/Restraint folder and select Uniform Base Excitation.
  2. Under Type, do the following:
    1. Select Displacement, Velocity, or Acceleration.
    2. For Face, Edge, Plane for Direction , select a reference entity.
      If you select a planar face or a reference plane, you can specify excitations Along Plane Dir 1 , Along Plane Dir 2 PM_along_plane_dir2.gif, or Normal to Plane .
      If you select a straight edge, you can specify an excitation in its direction Along Edge alongedge.png.
  3. Under Displacement, Velocity, or Acceleration, do the following:
    1. For Unit , select the desired unit.
    2. Click the button for a direction and enter a value.
  4. Under Variation with Time, select:
    • Linear to vary the excitation linearly from 0 at time 0 to its specified value at the end of the solution period.
    • Curve to specify your own variation or select a library curve. Click Edit to modify the curve.
    The shape of variation is applied to all specified values. Click Graph to view the variation in all selected directions.
  5. Under Symbol Settings, do the following:
    1. Click Edit Color to select a color.
    2. Set Symbol Size .
  6. Click .