Local Load analysis of Nozzles

In the Local load analysis as per WRC-107,
it is found that the calculation for the general primary membrane stress values (notation Pm) calculated are not matching with the result as obtained from the standard equations.

General Primary membrane stress values shall be calculated as follows,

Circumferential stress PR/T
Longitudinal stress PR/2T

I think, there may have some concentration factor, but values obtained in the case "loads on the junction of nozzle and shell", values showing much difference.

In compress software it is clear and accurate values with concentration factors are considered.

So please clarify these on the pvelite where the calculation on the General primary membrane stress are not clear.

regards
Abijith

Hi Abijith,

The WRC 107 method computes stresses on the upper and lower surfaces at the edge of the attachment. PV Elite uses the Lame equations and computes the surface stress on both the upper and lower surface of the shell. You should find these are accurate values. PR/T does not generally give an accurate result if the shell is thick compared to the radius. Also, note that the WRC 107 bulletin does not include the effect of pressure in the analysis.

Hopefully, this clarifies our approach.

Thank you for your reply regarding local load analysis.
I wish to feel free to ask for more clarifications regarding the same.

Here I am attaching a document where a line is highlighted with red colour.

Can you just tell me how the got these values, which are the circumferential membrane stresses due to internal pressure.

The methods I followed never meets that results.
Hope to get fine equation.