peteroznewman
posted this
09 December 2018

- Last edited 09 December 2018
Dear Harish,

Several loads can be applied to a Harmonic Response analysis. They are all present simultaneously. All the loads oscillate at the same frequency. The loads can have a phase relationship. That means if you have a force at the left end of the part pointing up, and another force at the right end of the part pointing up, if both forces have a phase of 0 degrees, then they are both going up together and down together, but if you put a phase of 180 degrees on the force at the right, then that force is going down at the time the force at the left is going up, and when the force at the left is going down, the force at the right is going up.

Once you have defined the number of locations on your structure where you want a sinusoidal load and defined its magnitude, direction and phase, then you define the range of frequencies that you want to observe the response.

If you are really interested in the response at 491 Hz, you can request just one result. What is more typical is to select a range, such as 400 Hz to 600 Hz and calculate results at a 10 Hz interval for a total of 21 result sets. In your example above, you only asked for 5 result sets, but at about a 100 Hz interval.

I hope this clarifies for you what is possible in a Harmonic Response.

What you can't do in a Harmonic Response is have two loads at different frequencies. That would require a Transient Dynamics solution.

Kind regards,

Peter