Thanks to jte and JStephen for their comments. I was looking to see if anybody had applied castigliano's thin curved bar theory to the problem to a quarter of the tank cross section and had come up with a proof or example I could work with. It's been some years since I done complex integral...
Can anybody tell me where I can find a mathematical proof of the stresses/deflections induced in a rectangular thin wall vessel subjected to an internal pressure?
Many thanks for your help in advance.