Good moring to everybody!
I have some problems related to the topic... So... I have this cylinder:
Radius= 275mm
Lenght= 1000mm
(conseguentely a=1000,b=1727.85)
I've applied a comprex load of 536.64 N/mm accordingly with NASA SP-8007 with a knockdown factor of 5674 by Hypersizer in the FBD page. I've used an one stack unstiffned concept leaving not equal to zero only the top face of the panel in order to simulate a simple walled cylinder. Using the NASA-SP8007 method with all clamped edges i've obtained a thickness of 2.51 mm while with analythical method i've obtained 2.5 mm that is absolutely correct. Now i have to study the effect of internal pressure. The internal pressure makes a bigger buckling load due to interaction with the benefic effects of the same pressure. I don't understand why if i choose a pressure value in Hypersizer, the margin os safety does not change.
Is it possible that the pressure isn't taked into account? How can i resolve this question?
Thanks for all the answers!