Hi,

I have noticed when I run the B31J on a B31.3 CII model, that the LR elbows calculated SIFs differentiate substantially from the original CII model which still uses the Appendix D. The formulas for SIFs calculation are the same between B31J and Appendix D, therefore I found it strange why this is happening. Has anyone else noticed something similar and is there any explanation to it? (I am only referring to elbows, not TEEs).

Thanks

If I am recalling my conversation with PRG correctly:

- FEATools is ahead of B31J (which was published in 2017). A new Edition of B31J is in the works.

- I believe there is some question as to the accuracy (correctness) of the "1.65" value in the equation for the flexibility factor.

Please contact Tony Paulin over at PRG for more precise details on this question.

Hi Richard and thanks for your response,

I will try to contact PRG for examining more the 1.65 value but let me be a bit more clear about my query.

My core concern is whether is logical the SIF (in plane / out of plane) calculation of an LR elbow to be different on the same (V12) CII model after I run the B31J since Appendix D and B31J use the same formulas*.

The 1.65 is used for the flexibility factor and is also same in both formulas (B31J and Appendix D).

I do not think it is worth to send the specific model since if you make any V12 CII model with LR elbows and check the in plane and out of plane SIFs and then run the B31J, you will see the different calculated values.

*To avoid any confusion, the B31J on page 2 for in plane and out of plane Sif formulas of welding elbows has an error -I assume- since instead of 0.9/h^(2/3) and 0.75/h^(2/3) for SIFii and SIFio respectively it uses 0.9*h^(2/3) and 0.75*h^(2/3) but later on page 15 it uses the first (/) which is same with Appendix D.
Strangely, I have not seen any acknowledgements for that on the web.

Thanks again for your time and effort,

I know there is an Errata published for B31J-2017 (I don't have access to this at the moment). PRG has this, or you can file a Support Request with Hexagon.

Dear Richard,

I have tried to contact Tony Paulin through email (tony@paulin.com) unsuccessfully. Can you please confirm his email address?

Thanks

Tony has responded, please send him your model as requested.