Re: Stress Intensification Factor

>Any thumb rule is there to calculate the SIF at
>defined interseting point For Example -At elbow or at
>Pipe to Reducer joint .

No general rules of thumb to cover all cases. For the two cases you cite, the mechanism of stress intensification is very different. Stress intensification in the elbow is like what happens in a curved beam under load. In addition there's a flattening effect that changes the stiffness. Den Hartog's book 'Advanced Strength of Materials covers the arithmetic. The stress intensification in a reducer or a tee comes from a local change in stiffness and a redirection of the loading. If you're into heavy math you can find all the information you can handle in standard texts on plates and shells. I expect the basis for the numbers used in code formulas was published in the ASME Transactions, or possibly in real comprehansive handbooks, but you'll have to do your own digging. People have been publishing test results and theoretical calculations for piping stress intensification since the 20's.

Christopher Wright P.E.    |"They couldn't hit an elephant at
chrisw@skypoint.com        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)