Apply the Loads

1. Right-click on Loads and select New.
2. Select Enforced Motion in the Type drop-down menu and Acceleration in the Enforced Motion Types drop-down menu.
3. Click the constrained point at the base of the structure.
4. Type in 1.0 in the ay box under Load Definition.
5. Click the New Table button next to the Load Factor drop-down, under the Frequency Table Data section.
6. Define your table as shown below, by double-clicking in the cells. Notice that the values are along the frequency of interest. Change the Name to vs. Frequency.

   

7. Choose Load Scale Factor vs. Frequency from the drop-down menu.
8. Click the Show XY Plot button to see the plot. It should look as shown below.

   

   

   

9. Click OK on the XY Plot dialog.
10. Click OK on the Table Data – ‘Table 1' dialog.
11. Click OK on the Load dialog.

With enforced motion loads (displacement, velocity, and acceleration), the direction that is desired to be enforced must be constrained. This may seem awkward, but just remember that enforced motion is constrained motion.