Originally Posted by Karsten
There shuld be formulas around for the wrinkling strength of tubes.
When the compression stress in the skin reaches 0.25*E*(t/r) the tube will suffer from local buckling (wrinkling).
E=stiffness t=thickness of tube r=radius of tube
This is a very simplistic formulae but is a good starting point.
Taken from a brilliant book for non engineers called "Structures or why things don't fall down" by JE Gordon see chapter "the various ways of failing in compression" (Penguin Books). I cannot reccomend this simple book enough.