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Simulation Mechanical and Multiphysics

New Member
Posts: 1
Registered: ‎10-15-2012

Random Vibration Power Spectral Density Results

335 Views, 1 Replies
10-15-2012 09:30 AM
When I get the results from a random vibration analysis after requesting power spectral density as an output, I have the option to graph the results for particular points on my model. The graph is labeled "Displacement Power Spectral Density". Are the results power spectral density (g^2/hz) or displacement spectral density (in^2/hz) and if the results are displacement spectral density, how do I get power spectral density?
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*Expert Elite*
Posts: 570
Registered: ‎08-30-2012

Re: Random Vibration Power Spectral Density Results

10-15-2012 11:12 AM in reply to: OrlandoRobinson

Hi Orlando,


I am not a vibration expert, but I think the displacement spectrum units are (in/sec^2)^2/Hz, not in^2/Hz. If the UI is showing in^2/Hz, then you will need to do a test to confirm if it is really (in/sec^2)^2.


If the results are (in/sec^2)^2/Hz, then I would think that you can multiply or divide by the value of g^2 to convert from one to the other.


John Holtz, PE
Mechanical Engineer
Pittsburgh, PA

Simulation Mechanical user since Dec 1997
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