Sir,
Stress Intensification factor(SIF)for 90 degree branch conection and 45 degree branch is same in CAESAR II. Why it is so?
Is SIF independent of angle of branch connection like 90 deg branch connection and 45 deg. brach connection?

Thanks

The piping codes only address 90 degree tees. The codes offer no guidance on laterals. This is why during "error checking", CAESAR II presents a "note" that the branch angle is something other than 90 degrees.

You need to talk to your vendor to see if they can provide an SIF. Your only other recourse is to perform an FE analysis of the fitting and numerically determine an appropriate SIF.

Hi Rakesh,

Of course your point is quite valid. The 45 degree elbow is NOT as flexible as the 90 degree fitting. I am sure you also know that flanges on the ends of elbows will also "steal away" some of the flexibility.

It is interesting that the flexibility factors and stress intensification factors are "turned on" at the "entering" weld line and "turned off" at the "leaving" weld line. Actually, the flexibility (and associated stress intensification) is the result of the cross sectional shape of the fitting being forced into a slight ovalization, thereby giving the fitting (pipe) a "strong axis" and a "weak axis". But the ovalization does not stop at the weld line and the flexibility carries on into the matching straight pipe (unless of course there is a flange there). But, in the long run, in most cases it work out and the Code gives you guidance to design a reliable piping system.

I wonder, when engineers develop SIF's by using an FEA model, do they carry the straight pipe out beyond the "weld lines".....about 4 or 5 diameters past the weld line would be good.

Regards, John.

Dear Rakesh,

The best you can do is perform a FEA analysis, but if you don´t have any help like the nozzle-pro, you can consider
45º = SIF (90º) x 1.5
60º = SIF (90º) x 1.25

Regards,

Please use the search fucntion. This question has been discussed here hundreds of times. (Besides, there is minimal lag time for an answer from the search function, especially compared to asking a question that will likely be answered by someone in a different time zone.)

CraigB is correct first we have to use search option then only we will likely be posted our querrys because few subjects repeatedly discussed.
sorry for my child english.

regards
senthil