We have an ethical problem. By raising thickness of a header, we could meet B31.3 area replacement reqt of a 45 deg lateral, which fails in NozzlePro FEA miserably for pressure load.

Is it ethically right to follow area replacement or intent of B31.3 code ?
reg,
sam

Sam, If I undetstood your question correctly, then you mean by raising the thickness you are able to satisfy the B 31.3 equation pressure design. But the same thickness your FEA result shows pressure failuer?

If that is the case then, I would prefer the FEA results more than anything else. Since as per B 31.3 para 304.7, it is the best way to move forward.

Regards,
R.K.

I think Tony Paulin's guys at PRG would be interested in your findings.

This sounds similar to what we find in the vessel world. In some cases, the pressure design of a vessel nozzle in accordance with ASME Section VIII Division 1 (design by rule - area of replacement) fails a Division 2 check (design by analysis).
Passing the Division 1 check remains acceptable.

Sir,

Your legalese we accept.

But, in present era, when GP uses echo in place of stetho, FEA for pressure design by Division 2 check (design by analysis) should be a de-facto standard of pressure integrity!

Unfortunately, due to work share, FEA software is used by very young, inexperienced engineers in a wrong way in some parts of the Earth!

They create the myth that different FEA software give different results, even different element types in same software, which is not at all true!

Just Newton's three laws are applicable everywhere, FEA, if used for SIF extensively, should be used in pressure design, too!

regards,
sam

PS: Today is World Heart Day; take care, and let us live for others around!

Is ASME Section VIII Division 1 (design by rule - area replacement) sufficient enough for pressure design for d/D >0.5 & <= 1.0 45 deg WYE applications, which are borderline cases, when FEA calc show primary Pm+Pl stress failures ? If failure occurs, who will bear the blame!

regards,
sam

To be precise, instead of multiplying the allowable stress by 1.2, the
pressure used in the analysis is multiplied by 0.90 and the earthquake loads by 0.7. Thus,wind, snow and other occasional loads are considered at their full value in table 5.3 of ASME Sec VIII Div-2.

regards,
sam