Analysis of Sign post

[ksarita20]

Hi,


I have to do a structural analysis on a sign post pole.( i mean the vertical rod only).Ihave touse pro/e.


The data i have is the constant air velocity, the dimensions of the sign pad( this pad is welded to the sign pole.) and the dimensions of the pole.



I dont need toseethe stresses inthe pad, i only want the stresses in the pole.



Now my question is, how to transfer the velocity effect on the pad into force and how to transfer this load on to the pole.


Please guide me. i need help.
thanks in advance
Sari

 

[lindejos]

Go grab a Fluid dynamics book. You can use the Reynolds, Prandtl and Nusseltnumbers of the air to find the pressure on the sign. It will be very similar to any airflow problem in the book, but be careful with your assumptions. Then you can take the pressure over the area of the sign to the force. Once you get to that point you can model the pole and take it into Mechanica.


If the bottom section of the pole (the part that will be in the concrete) is a separate protrusion it will be easier to map the constraint to that feature. There might be a more poetic way to do this but thats the first thing that came to mind.


As for the sign: asimple solution would be to apply this force on a datum curve over the length of the sign.


A more complicated, but accurate solution would be to model the bolt connections between the sign and the pole and apply the loads there.


A note: If you use a midsurface shell on the pole, the first solution won't work. Mechanica seems to have a problem projecting the datum curve onto the shell surface. Don't ask me why, I'm just relaying my experience.