Hi,

I was reviewing the article titled "WRC 107: Elatic analysis vs. Fatigue analysis" in the COADE mechanical engineering newsletter from June 2000 (you can download it from the site). Does anyone know how caesar II breaks down the applied loading into Pm, Pl, Q, and F for Div. 2 calculations? Does anyone have any more information / reference on this methodology? Any help would be greatly appreciated.

Thanks,
Primary Membrane

Dear Pm+Pl... (very amusing)

CAESAR II is a beam element program that uses a simplified approach to analysis that the piping codes take. As such the world of three dimensional FEA and Section VIII Div 2 that your name alludes to does not exist per se.


I suggest you pick up a code book or do some more downloading and reading. In general you will find the B31 codes separate loading by types, and issues such PM due to pressure are not even a part of the world of flexibilty analysis per se (excluding pressure stiffening of elbows).....

Dear John,

Thanks for the advice but I am referring to a module that is part of CAESAR II specifically for the analysis of the vessel-attachment junctions. WRC 107 is a bulletin provided by the welding research council providing guidance and empirical based formulas to analyze local stresses in spherical and cylindrical shells due to external loadings. Maybe you misread WRC for FEA but I hope this clears things up. I take it by your response you did not read the article I was referring to and you have never used this module?

Regards,
PM

Ahh excuse my confusion.... WRC107 yes indeed three dimensional analysis sort of...

CAESAR II follows the original WRC107 bulletin with no modifications so all the references as far as pl etc. are per WRC107.

Incidentally if you take a read on the original paper you will find that peak stresses as you will get from FEA are not necessarily captured by WRC107

Does this address your question?

You need to look at the CAESAR II User's Guide for this info (specifically page 12-13). If you don't already have access to this it can be downloaded from this site under Caesar Downloads.

This provides a bit of information. I would like to know how CAESAR II uses the three stress components computed by WRC 107 (circumferential stress, longitudinal stress, and shear stress) and then breaks those values in Pm, Pl, and Q (div. 2) for the cirumferential, longitundinal and shear directions (i.e. WRC 107 gives you 3 stresses, CAESAR II gives you 9). Does CAESAR II take the individual results from WRC 107 and sum them up differently to arrive at 9 results? I can't find the technical reference so I don't if its explained in there.

Yes, the Technical Reference Manual is what you need. I don't think it's available to download and it's not mine to give. If you're not a fully paid up union member can I suggest you try the demo download (not sure if manuals are included) or better still fire an email off to COADE who may be able to help you further.

All of the CAESAR II documentation is provided on-line with the installation of the software. From the Main Menu, select "Help", then "On-Line Documentation", then pick the "Technical Reference Manual".