Dear Users and Customer Service,

I`m using Caesar for the first time, during a pipe analysis based on ASME ND-Code two questions occured.

1.) A maximum Stress was located in a pipe bend, and I have not been able to confirm the results of the dynamic data output by a simple calculation by hand. Please look at the the attached document, which includes data output and calculation on two pages. The results show a difference of about 12%. According to the "Quick reference guide", chapter code stresses, you pretended to use the ASME formulas. Why is there a difference, in my opinion the values should correlate exactly?

2.) Isn`t it irritating to feature only SIF-Values in the dynamic data output although the following Code-Stress-determination is based on B1, B2 - Indices (so as the determination of allowables). Wouldnt it be helpful to feature the values of B1, B2 ?

Kind Regards, Rick

Rick,

Please send your .CAESAR II file to techsupport@coade.com so I can confirm the calculation. I will post my hand calculations here when done. Be sure to tell me which node and load case I should be looking at.

Stupid question of the day, but would this maybe be related to the 12-1/2% manufacturer's tolerance?

SLH

This is a combination load case where S2 is the static sustained case and D1 is the dynamic shock case. This combination does not use the moments that were pointed out in the pdf file above. Instead it combines the code stresses from the static sustained and dynamic shock case directly according to the method selected in the Directives dialog accessed when on the Static/Dynamic Combinations tab. In this case the blank indicates the default of ABS (absolute value) method was selected (as opposed to SRSS). From the file sent to me here are the code stress results:

SUS = 21.0744 N/mm^2

D1 = 80.256 N/mm^2

D1+SUS= 101.33 N/mm^2 This is the number reported in Caesar II's output referenced above.

Now, if you want to try to prove to me that either the dynamic code stress or the static sustained code stress is pretending to use ASME code stress formulas instead of actually using them correctly, you are welcome to re-post in this thread. But I am not going to take the time to prove they are correct.

Well, I had nothing else to do today so I decided to perform the entire calculation for SUS and Dynamic Shock case for this particular job. The results match Caesar II's with extremely good accuracy. See the attachment for all the details. I think this should put to bed any comments that Caesar II is not doing this calculation correctly.

Danke Herr Brown for doing this homework assignment WE are all very grateful (not that I was particularly concerned)

The way to combine the stresses of the static loadcase and dynamic loadcase which Caesar II uses is correct. ASME Code ND clearly advises to combine the resultant moment for static loadcase Ma with the resultant moment of the dynamic loadcase Mb (B2*(Ma+Mb)/Z). ASME ND does not advise to combine all directional moment components in the same direction before determining the resultant moment.

In opposition to that ASME Code NB-3652 (2004) advises to combine components before determining the resultant moment. Thats what I did, it leads to lower stress. The combined directional moment components in the same direction occur on the dynamic data output, that confused me.

In fact we are working with ASME ND, so you are obviously right.

Regards, Rick