ASME VIII D1 2017 Appendix 2-14 - Rigidity criterion explanation 1

[Matthieu Bories]

Hello everyone,

In table 2-14 of ASME VIII D1 2017, 3 formulas are purposed to assess a rigidity criterion J following the type of flanges (integral, loose with hub, loose without hub).

On another closed thread, I saw that these formulas actually calculate the flange rotation in degree, divided by Ki or Kl which are maximum rotation in degreee (0.2 or 0.3).

It is a very important information for code interpretation, but I would like to have a more detailed explanation about these 3 formulas.

Someone knows where it can be found an explanatory note about this? Or someone knows where do these formulas come from? Maybe Roark's?

Thank you

Matthieu

 

[mskds545]

I'm a bit late on this, but I just came across it and thought I'd answer if you're still interested. It comes from the same place as the rest of Appendix 2: "Development of General Formulas for Bolted Flanges", Waters, Rossheim, Wesstrom, and Williams. You can read it at

https://babel.hathitrust.org/cgi/pt?id=uc1.b4485764&view=1up&seq=150.

In the code formula, let KI*J = theta, and note that 52.14 = (1-0.3^2)*180/pi. Also, Waters lever arm a is equal to the Code's (C-G)/2. Start from the form of theta in Appendix W on page 51. From there, it's a matter of simple substitution to show that the Waters formula and Code formula are equivalent.

-mskds545