Loads that vary in value and direction during a specific time range can be very hard to simulate. Some examples: ventilators, explosions, off-shore, ... In Autodesk Robot Structural Analysis, an advanced dynamic analysis called Time History Analysis can be a solution for this. Basically THA is used for solving specific seismic problems, but can be configured like in the case below as well.
The video below shows the steps to take in order to make an animated result of the effect of a time dependant, harmonic load on a structure. The simulation is done by applying a horizontal force with a sine function over a defined time period for a frequency of 3Hz and analogue a vertical force applied with a cosine function.