I've been asked how CAESAR II calculates stress in pipes, and I've yet to find a good answer in the documentation.

Does CAESAR II use the p or h or other method to analyze the stress?

Is there a place in the documentation I can read about the method?

Thanks,

Hello Mr. Hudson,

The system parameters described by the analyst in developing the analysis model are used to define the global stiffness matrix [K] and load vector {f}. This defines the system of equations [K]{x} = {f}. Caesar II uses classic beam theory (the finite elements that CAESAR II uses are beam elements) as prescribed in the Code that the analyst chooses when modeling the system. Caesar II calculates the forces and moments in the piping system due to the loadings the analyst describes in choosing the load combinations.

Assuming that you will be using one of the ASME B31 Codes for Pressure Piping, you can look in the appropriate Code and you will see the equations that Caesar II uses in calculating the primary and secondary stresses from the forces and moments (including Code SIF's etc.). If you want to see the method of stress calculation for B31.1 or B31.3 you can find the equations in Chapter II of each document. You can get a very good description of this process by referencing one of the two good books CURRENTLY available.

Process Piping: The Complete Guide to ASME B31.3, Second Edition, by Dr. Charles Becht IV, http://catalog.asme.org/books/PrintBook/Process_Piping_Complete_Guide.cfm

CASTI Guidebook to ASME B31.3 Process Piping (Fourth edition), ISBN: 0071364714, by Glynn E. Woods, and Roy B. Baguley
http://www.casti.ca/ (click on books and ebooks)

and for a preview ,
http://www.casti.ca/books_ebooks/lite/B31_3_lite.pdf

You might also want to look at this previous discussion:

http://www.coade.com/cgi-local/ultimatebb.cgi?ubb=get_topic;f=1;t=001122#000001

Regards, John.

Thanks, John.

I'm working on my first analysis and I know that this is going to be one of the first questions senior engineers and management will ask me when I present the results, as they are unfamilair with the software.

Hudson DeLee

I hope that you will have your worked checked by an experienced person.... there are numerous ways to cut ones throat without even knowing that one has indeed cut ones throat!

Hello Hudson,

As allluded to by our learned colleague, Mr. Luf, you will find that the structural analysis of piping systems is significantly different from similar analyses of other structures. May I respectfully suggest that you visit my posting on (near the end) this thread:
http://www.coade.com/cgi-local/ultimatebb.cgi?ubb=get_topic;f=1;t=001336;p=1#000003

Good luck and do not hesitate to check back with this discussion community.

Regards, John.

Please note I have cut my own throat more than once and have been saved by another person asking me why I did something.... if I have been doing this work for over... well lets say a long time and I feel I need a competent checkers eyes on my work then you as a neophyte well guess the rest.....

As for FE versus anything else I suggest that you bone up on the code your work will be done in accordance with more so than the methodology details.... knowing about flexibilty matrix methods won't give you the knowledge you will need to get the right SIF or load cases set up...

Ask questions and consult....

Dear Hudson,

Please develop the support infrastructure in your organization so that your mentors/seniors send you to some training seminar for this software, if you have not received one such already. There, you may get some peers and mentors to get your work checked.

It is difficult, but not impossible, to be confident just by reading book, code and documentation.

Moreover, you have to choose between 100 yards sprinter or marathon runner - what you want to be.
Sleek FEA powerpoint presentation without realty check of practical problem solving in your area of application can incite admiration which has to last long, which you can get in training only.

"Give a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime." A Chinese Proverb

regards,

sam