Soil Simulation

[Anonymous]

Hi all,

I need to do structural analysis of a rotating equipment foundation to check the adequacy of the foundation to handle any lateral load. I have modeled concrete foundation and equipment. I would like to know the modelling options of soil (like compression spring)beneath the concrete foundation. Any recommendations on how to simulate soil?. Thanks

[shigeaki.k]

Hello @Anonymous,

Autodesk Nastran In-CAD does not have solid constituent (see IdeaStation request for this here). You could try using springs such as grounded springs or regular springs. The number of springs will be need to be set to match empirical results. This site here may also be of interest. 

Regards,

Shigeaki K.

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[rlkillian]

Several years ago I worked at a large company that had an expert on staff for analyzing foundations supporting rotating equipment. He taught me some things that unfortunately I've forgotten the details of most of. I do remember that if you are talking about large powerful equipment, it's much more complicated than you would imagine if you've never done this type of thing before. It seems like the rule-of-thumb for when to start doing more in-depth vibration study was 500 hp. Can't remember if that was for reciprocating or centrifugal compressors.

The particular one I worked on had a pile supported foundation and just determining the equivalent spring constant of the soil was very complicated due to the fact you had to make adjustments for the fact it was a dynamic analysis and you had the consider the interaction of all the piles.

I know this isn't real helpful but I just want to make you aware this may require an expert in the field of equipment foundation vibration. The first time I ever did this I didn't know what I didn't know.