STIFFENING RING

[Danfort]

Hi,

What is stiffening ring?And why is it required for vessels operating in vacuum?

Thanks and Best Regards'
Dan

 

[brkmech1234]

A stiffener ring is a ring with cross section in various shapes like L,I ,T etc or any other shape attached to the vessel either inside or outside of the vessel.These are required to reduce the compressive stress induced in the shell due to external pressure and helps in reduction in thickness of shell and thereby economic design.

The required thickness of shell for an external pressure depends on the diameter of shell, effective length of shell and material properties. The effective length of an unstiffened shell is equal to length of shell +2/3 depth of head . Higher the effective length, higher the thickness required. If a stiffener require ring is provided, the effective length will now reduce to the distance from stiffer ring to shell end + 1/3 depth of head and thereby required thickness will be reduced. If vessel is very long it is practice to provide multple number of stiffenrs. When the multple stiffeners are provided , the effective length is maximum of distance between stiffeners and distance from the end stiffener to shell end + depth of head. Please refer UG-28 of ASME VIII Division 1

 

[Compositepro]

One point of clarification, stiffener rings do not reduce compressive stress on the shell. It stiffens the shell so it will not buckle.

 

[brkmech1234]

To be precise, Yes. I think I have stated in general sense. Thanks for correcting me