Stress on a Circular Plate

you do not say what the material is, but you may try API 650 appendix G

Sorry about that.

The material is reinforced thermoset plastic (fiberglass).

Thanks for the lead.

if it is FRP try ASME Boiler & Pressure Code section X (ten)

Can you add a vertical pipe support at the edge of the tank so that the reaction is taken directly by the tank wall instead of the circular plate? Or alternatively, can the actuator be suspended from something else, thus removing the problem entirely?

If not, then the load and moment is very close to the edge of the plate. You would not be far off if you assumed it to be equivalent to a narrow band (say two feet wide) spanning across the diameter of the tank. Maximum stresses will occur at the pipe attachment or at the edge of tank or both.

If you need more accuracy than this, you will need to do a finite element analysis or combine known solutions to give you the load and moment consistent with your problem. "Theory of Plates and Shells" by Timoshenko and Woinowsky-Krieger has a solution for a circular plate with fixed edge and a concentrated load located off center.

You could consider two concentrated reactions aligned with the horizontal leg of the pipe and acting at each end of the pipe diameter where it enters the tank. The magnitude of the reactions would be 500/2 ± 19000/d where d is the pipe diameter in inches. You could then combine the two solutions using the principle of superposition.

It would not be 100% accurate because it does not take into account the hole in the plate. FEA is likely your best bet.

Bruce:Of course I can't use external supports. Where would the fun be in that? Seriously, not an option for my Client. However, you're right. I can convert the moment into equal and opposite loads as a function of the pipe diameter, compute the individual stresses, and then use super-positioning. I realize it won't be exact, but it will be reasonably accurate. Given a required F.S. of 5, and given the historical variations in FRP fabrication, a more precise answer would be meaningless.

Thanks for your help. I should have realized this. As Homer says:

"Doh!"