Shell buckling
Shell buckling
(OP)
Hey!!!
I designed a simple long thin open ended cylinder in ANSYS and the type of loading is hydrostatic pressure.
I calculated the buckling pressures for different modes shapes (n=1,2,3...) using Von-mises and Donnel's equation.Both have used classical simply supported boundary conditions.I constrained all translations(x,y,z) on one end and two translation(x,y) on other end as classical simply supported conditions.There is a huge difference in theoretical and ansys results.
I am sure that that is happening because of boundary conditions.Can anyone explain or tell me what are classical simply supported boundary conditions for cylindrical shell?
Regards
I designed a simple long thin open ended cylinder in ANSYS and the type of loading is hydrostatic pressure.
I calculated the buckling pressures for different modes shapes (n=1,2,3...) using Von-mises and Donnel's equation.Both have used classical simply supported boundary conditions.I constrained all translations(x,y,z) on one end and two translation(x,y) on other end as classical simply supported conditions.There is a huge difference in theoretical and ansys results.
I am sure that that is happening because of boundary conditions.Can anyone explain or tell me what are classical simply supported boundary conditions for cylindrical shell?
Regards





RE: Shell buckling
i'd play with your model with different constraint scenarios untill you get correct hoop behaviour (under tension).
i've also seen odd behaviour depending on how i created the geometry.
RE: Shell buckling
RE: Shell buckling
then see if you get good "hoop" behaviour.
RE: Shell buckling
RE: Shell buckling
RE: Shell buckling
RE: Shell buckling
You're modelling a cylinder under internal pressure and you haven't ever used cylindrical coordinate systems before and you're wondering why you have problems?
RE: Shell buckling
Regards
RE: Shell buckling
It's a cylinder. That's the reason that cylindrical coordinate systems were invented... Next you'll be asking about spheres, and then admitting that you've never used spherical coordinate systems either.
RE: Shell buckling
Isn't there a way to use a local co-ordinate system instead of the global co-ordinate system ?
RE: Shell buckling
Sure, you could use a local cylindrical coordinate system. That's the point.
RE: Shell buckling
RE: Shell buckling
a) modelling something that is a cylinder, and
b) applying boundary conditions that would be best described in a cylindrical coordinate system, and
c) yet haven't ever used cylindrical coordinate systems before, and finally
d) have unexplained problems
then you may have a problem with your boundary conditions (and the coordinate system that you have defined them in).