Sphere in sustained and operating conditions 1

[Daniel10]

Hy every one!
I'm trying to build a model for an LPG sphere and put the loads on it.
If anyone could help me with a similar model to compare, it would be better for me. From weight and pressure the results seem to be good , but I don't know to put the seismic and wind loads.
If any one has done that, a complete analyses of a sphere, in sustained and operating conditions please send me some information.
Thank you!

 

[cbrn]

Hi,
I don't have info to send but some methodological hints...
1- wind load: first of all, check if you must follow a Technical Directive or a Norm for your case. For instance, high-voltage line supports in Italy are subjected to the CEI directives, and they specify very clearly how to set up wind load; then, the application is easy: once you have the wind pressure value, apply it via "surface effect" (you have to create "envelope" elements of SURF- type for that) in order to be able to make a directional pressure (not normal pressure).
2- seismic load: this can be REALLY involved. Basically, you surely have to respect some Norms which apply in your Country. Most probably, they will give you guidelines to set up excitation spectra (ground acceleration spectra) in horizontal plane and in vertical direction, taking into account the local sismicity of your erection site, the soil type, etc. Then, if and only if your model does NOT have any non-linearity, you can follow the simple way: set up an harmonic response analysis and apply the spectra at your fixed points. I'd suggest static analyses and harm-resp analyses to be kept separate, you can then combine results by post-processing (this is needed especially if you follow the Limit States methodology. If, instead, you must incorporate some non-linearity, then you must go into a full-transient analysis, and in order to do so you will have to convert your acceleration spectra into displacement spectra and then into a time-variant law of displacement: good luck !!!! :-(

Hope this helps...

Regards

 

[Daniel10]

Thanks, cbrn!
Your reply gave me some general guidelines to follow.
I don't know where to find some examples with the steps and also some real results to give me an idea of how far I am from the right solution.
Thanks again for your help.
Best regards!