Weld Strength Paths...v.2.0

[BigTank]

thread794-247823

One year+ later...

Please reference the attached thread, with this in mind:

I've been able to satisfy myself with just about everything but this:

(b) PI/2*mean nozzle dia.*tn*Mod Allowable S

How is this the nozzle shear failure capacity portion of failure path 2-2 in Fig. UG-41.1? Why is it not something like:

PI/2*(O.D.^2-I.D.^2)*Mod Allowable S?

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Fitter, happier, more productive

 

[BigTank]

My apologies...this should be in the ASME Code Issues Forum...

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Fitter, happier, more productive

 

[doct9960]

BigTank,

(b) PI/2*mean nozzle dia.*tn*Mod Allowable S

How is this the nozzle shear failure capacity portion of failure path 2-2 in Fig. UG-41.1?

In your thread794-247823, you were talking about the calculations in L-7.2 which illustrates reinforcement and strength calculations for a nozzle inserted through the vessel wall. Thus the nozzle wall shear is in the path 1-1 in sketch (a) of Fig. UG-41.1

Why is it not something like:

PI/2*(O.D.^2-I.D.^2)*Mod Allowable S?

Don't you mean PI/8*(O.D.^2-I.D.^2)*Mod Allowable S?

 

[DSB123]

BigTank,
Think your proposed eqn should have Pi/4 and not Pi/2. In which case both equations would yield the same results.

 

[BigTank]

Okay, here's what I found...doc and dsb are correct. The PI/2 in the full area equation was a typo, I did mean PI/4. Here's the solution to my confusion:

If I calculate for the same nozzle

PI*mean nozzle dia*tn=PI/4*(O.D.^2-I.D.^2)

as dsb suggests, but UG-41(b) states 'one each side of the plane defined in UG-40(a). This detail is what makes doc's equation correct with the code:

PI/8*(O.D^2-I.D.^2)

which yields the same results as the code's version:

PI/2*mean nozzle dia*tn.

Bingo! Man, that has been bothering me for a long time now! I just put my trust in the software last go around. Since it's Friday, I might do the algebra to get from one equation to the other, just for exercise.

Thanks guys (girls?)!

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Fitter, happier, more productive