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Vessel on rings according to procedure 3.5 (Dennis R. Moss)

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anaxpress

Mechanical
May 30, 2003
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Has anybody used the procedure 3.5 on the book Pressure Vessel Design Manual from Dennis R. Moss? Do you know a better option?
Thanks for your help
 
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anaxpress:

Sorry I can't comment directly on the section you are having trouble with, but MANY other sections of the "Pressure Vessel Design Manual" (both editions) are FULL of errors and ambiguity. If you are not very experienced in this area I would suggest contacting someone who is or at the least, looking for another pressure vessel handbook for your design. I haven't used all of them, but here are some others you might check into:

Pressure Vessel Design Handbook by Henry H. Bednar
Pressure Vessel Handbook 12th ed by Eugene F. Megyesy
Roark's Formulas for Stress and Strain by Warren C. Young, Raymond J. Roark
Pressure Vessels: The ASME Code Simplified by Robert Chuse, Bryce E. Carson
Guidebook for the Design of ASME Section VIII, Pressure Vessels by James R. Farr, Maan H. Jawad

I would look at the Bednar book first... I'm pretty sure it has some design stuff for vessels on rings.

Good luck!

jproj
 
I am not aware of the procedure in Moss for the design of vessel on rings.

I am familiar with the method in Bednar and Jawaad/Farr texts. This is the method that I believe that some of the software uses.

These are both based on the method in Blodgett titled "The design of Hangers and Supports for Shells and Similar Sections" This publication refers back to an ASME paper from 1933 by Von Karman. There are some differences in the current design method. The Blodgett method makes allowance for the stiffening effect of the shell in terms of a combined moment of inertia. The current publications do not take this into account, which results in a more conservative design.
 
Thank you very much for your quick answers!

I've heard before about all the mistakes in the Moss text...

As you suggested, I´ve been checking the Bednar handbook (Second Edition) and also the Blodgett, but there are still some things I would like to ask you about.

About both books, calculations are made as if you have only one gusset at each support point. What if you have two? Don´t you have to take into account the angle between them? (Forces and moments distributions are not the same).

And about the Bednar, if you don´t use the shell to calculate the maximum stress, how do you determine the minimum shell thickness? Just with Stress=Press*Radius/Thickness?
 
Hi anaxpress,

I don't know about the methods in any of the other books, but I have used the method in Moss. If you have two gussets, you need to look at procedure 3-5, Fig.3-19 & 3-20. If you need more help, let me know directly.

email addy - johnfo@murrob.com

Regards
john
 
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