Questions about Nozzle Pro

[Matrix_93]

Hello,
I have a question about Nozzle Pro program.
When I have to calculate a nozzle with FEA Analysis in the program

 

[TGS4]

Pb and Q are stress categories of the bending stress classification. The loads are not primary or secondary, the stresses are.

 

[Matrix_93]

Thank you for the reply TGS4 and I agree with you about stresses primary

 

[r6155]

Matrix_93
Try with hand calculations.

Regards

 

[Matrix_93]

r6155 I used calculation by hand.
I verified Nozzle Pipe and Shell thickness with Pressure and bending moments "distant" from nozzle-shell intersection and there are no problems:
σ = P*D/2*t + ML*D/2*I + MC*D/2*I
where
D = external diameter (Pipe/Vessel) [mm]
t = thickness (pipe/vessel) [mm]
Mc, ML = circum./long. bending moment [N*mm]
I = moment of inertia of pipe/vessel section [mm4].
My equipment is a pressure vessel at 25 barg in SA-516 Gr.70 at 250 °C.
Nozzle is 12" self reinforced.
That I don't understand is how to consider bending moment concentration stresses close to opening by hand.
With WRC formulation I have to use k*6*M/t^2 as stresses due to bending moment and the final result is very high, much higher than FEA analysis.
M = 150 kN*m -> 150kN*m/m
t = 25 mm
σ = 6*M/t^2 = 1440 MPa

 

[r6155]

You need to be patient and try to understand WRC.
What WRC number and what year are you using?

Regards

 

[Matrix_93]

I have WRC 537 Last edition!
Could you give me some advice please?
I don't understand why 6*M/t^2 leads to an high stress due to bending moment.

Many thanks for your help.

 

[r6155]

1) Search the errata
To: All WRC Subscribers and purchasers of WC 537
From: WRC Publication Staff
Date: April 2011
Subject: WRC Bulletin 537 Errata


2) Sorry.
Do you think that someone can help you without enough information ?: complete details drawings, the complete calculation you made, etc.......and free with internet?

Regards

 

[Matrix_93]

I wanted to know something more about 6*M/t^2 and I have always been kind.
Next time you will see a question that for you is useless or without hope. Please don t answer.

Regards