Buckling of Stringer Stiffened Cylinder

[RonMB]

I have a horizontal pressure vessel designed to ASME Sec VIII, Div 1. If I add longitudinal stiffeners at the point of maximum compressive load, am I still limited by the allowable compressive stress as determined for B in UG-23(b)(2) or may I use the higher limit of the tensile as in UG-23(b)(1).

I was once told that the factor B calculation was only for unstiffened cylinders, I cannot verify that statement.

 

[prex]

UG-23(b) is for an unstiffened cylinder, and, as far as I can remember, there are no rules in ASME VIII for longitudinally stiffened cylinders.
You will need to set up your calculation procedure to justify your stiffeners, and of course you can't jump to UG-23(a) without justification.
I assume you are not concerned with vacuum in the vessel, otherwise you should of course go also to UG-28.

prex

http://www.xcalcs.com

Online tools for structural design

 

[RonMB]

Prex,

No vacuum, just beam loading.

Is there a statement in the Code that UG-23(b) is for unstiffened cylinders?

Thanks for your input.

RonMB

 

[jte]

RonMB-

The "B" factor is applicable to unstiffened cylinders. In your case, I'd suggest evaluating your design using Code Case 2286-1, Alternate Rules for Determining Allowable External Pressure and Compressive Stresses for Cylinders, Cones, Spheres, and Formed Heads. I believe that it could be used for a longitudinally stiffened shell.

jt

 

[jte]

Ok, I'll correct myself before somebody else does. CC2286-1 does not apply to longitudinally stiffened shells.

jt