Div 2 Part 5 (Design by Analysis) applicability to Stiffening Rings around a Vessel

[Vicker85]

Hello All,

I am doing Static Elastic Analysis for internally pressurized vessel which has stiffening rings around it. Note that this is not exactly a PV and these stiffening rings are not exactly for FV loading. I am using Shell Elements to model the entire geometry.

I have high stresses at certain locations at the junction of Vessel Body and Rings when internal pressure is applied. The high stresses are on the Ring essentially.

My question is : Can we categorize stresses (Pm, Pm+Pb, P+Q) here and compare against code allowable for protection against plastic collapse? if Yes, and if we are to apply Stress Linearization (although linearized stresses Pm, Pm+Pb are available for Shell Elements), how would we choose SCL for these areas of Ring to Vessel Junction ? Can we apply the same idea of that for a Nozzle-Shell Junction ?

 

[MJCronin]

" this is not exactly a PV and these stiffening rings are not exactly for FV loading "

??????

Can you show us a screenshot or a drawing or something ?

Are these insulation support rings or something ?

MJCronin
Sr. Process Engineer

 

[Vicker85]

Thank you for you reply. I am sorry but i cannot share any pictures here

However, let me try to explain the construction:
I am analyzing a high pressure steam sparger system for stresses. So, this long sparger pipe (assumed as a PV) has small orifices located longitudinally. The orifices are only on 45° circumference of the pipe! To re-direct the high velocity steam, there is a 90° 'curved hood' - all along sparger length. This Hood is part of the sparger assembly. This Hood is connected to the sparger pipe via plates at certain distances - which in my question i have refereed as stiffening rings.

Again, apologies for making this description in absence of drawings etc.

Please let me know if the description is not clear!

 

[TGS4]

Please read 5.2.1.2 and 5.2.1.3. Your answer is in there.