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Random loads (PSD) + Static Loads (inertial acceleration)

j.marotta
Hello,
I'm concerning with Random analysis using either MSC Random Tool either Nastran.
I have a PSD table (Hz vs g^2/Hz) on wich I need to superimpose a static load expressed in g.
So I have a random "load" plus a static load, how can I evaluate their effects when acting together?
 
Thank you 
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    What specifically is this meant to represent? If you are looking for the static load to act as a preload, then that is done using STATSUB.
     
    I did a quick search and found where a coworker answered a similar question in the past... here is that comment: "Normally one would not combine the static result with the random result since this may lead to misinterpretation of the stress data. The static stress is the average static stress value and the RMS is the mean vibratory stress value. I don’t know what this would represent in a physical sense although one could add the static stress value to the RMS stress value. I think you will have to add the static and RMS stress values outside of either Patran or MSC Nastran to obtain a sum."
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  • 0
    What specifically is this meant to represent? If you are looking for the static load to act as a preload, then that is done using STATSUB.
     
    I did a quick search and found where a coworker answered a similar question in the past... here is that comment: "Normally one would not combine the static result with the random result since this may lead to misinterpretation of the stress data. The static stress is the average static stress value and the RMS is the mean vibratory stress value. I don’t know what this would represent in a physical sense although one could add the static stress value to the RMS stress value. I think you will have to add the static and RMS stress values outside of either Patran or MSC Nastran to obtain a sum."
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