SIF

Regarding SIF few queries -
1) ASME 31.3 uses directly all the formulas given by Markyl after his fatique test evaluation ,where he neglected below things-
A) impact of torsional stress is neglected while calculating in plane and out plane SIF.- if header is of higher size as compared to branch WRC330 SAYS IT MAY CAUSE PROBLEM.
B) impact of reduced intersection is not considered,Markyl uses same SIF for branch and header irrespective of size but same thing we don’t use in caesar .
Caesar automatically calculates SIF for brance and header ,my question is why it is so ?
If 31.3 says to use same SIF on branch and header why Caesar uses reduced intersection effect ?

bINU

For 4 inch Std pipe, with a 4 inch Std branch c2 yields:
Header SIF(i) = 3.169
Header SIF(o) = 3.892
Branch SIF(i) = 3.169
Branch SIF(o) = 3.169

For 4 inch Std pipe, with a 2 inch Std branch c2 yields:
Header SIF(i) = 3.169
Header SIF(o) = 3.892
Branch SIF(i) = 3.169
Branch SIF(o) = 3.169


Now, Paragraph 319.4.4,c states that the bending stress component for the branch be determined using Zeff (the effective section modulus). Note that the bending stress equations for both the header and the branch use the same SIFs (as computed above). The difference in this stress calculation is only the effective section modulus.

Dear everyone,
I search for SIF in the forum and comming up with this page.
I have attach the capture for the SIF value for 45 degree branch.
Here are caesar II input
1. Input 1


2.Input 2



Please take review and comment which one is correct.

Please noted that the input is from node 110 to node 500 for branch.The SIF(i) and SIF(o) still same or not when the input is from node 500 to node 110?
I am confusing about this.
Thanks

Used-entered SIF's are applied ONLY on the "side" of the nodes where entered. User-entered SIF's should override the calculated values for the intersection. You can see the SIFs in the output report.
One difference between using the SIFs and using RFT definition is the section modulus (Z) used for the branch pipe. SIFs may not use the reduced Z, even though the RFT does. That's a function of the piping code used and the branch size.

Thanks for quick response.

I have read the subject" User-Defined SIFs anywhere in the Piping System" from Caesar II Manual but still confuse.
regarding to above picture, there are 3 elements
1. From 100 To 110
2. From 110 To 120
3. From 110 To 500
Could you please specify which element the SIF will be active at node 110?
I found that the in put was different from people to people.

If you're going to "manually specify" the SIFs, you need to specify them on all three elements that frame into node 110. You should be able to confirm this by reviewing the SIF values that appear in the Stress Report for these elements.