Hi,

I was wondering if anyone has any experience modelling grayloc fittings? Is the correct modelling concept of the connection a flexible coupling with bi-linear moment rotation relationships? If so, does anyone have standard rotational stiffnesses they use?

thanks,
Ed

Normal practice is to model a grayloc the same as a conventional flanged joint, two rigid elements back to back. That way you pick up the loads at the gasket. If your torsional moment is large enough to cause slippage in the joint, you will probably have wrecked the gasket surface.

Hi MoverZ,

Do you have any allowable loads information for checking against?
I have contacted Oceaneering, who have apparently acquired Grayloc, but have yet to get a response.

Thanks.

Vincent

Hi,

If you are working on a specific Project, with a reputed Client (e.g. TOTAL, STATOIL etc.) and with Procurement conditions already settled and confirming Gayloc connectors, then Oceaneering will probably respond.
I passed through such experience on some former projects.

Otherwise, yes, Grayloc catalogue does not include the allowable loadings.
In such case, you might have three options:

1) Develop an in-house calculation spreadsheet (Excel, Mathcad) based upon ASME VIII-1/App.24 or ASME VIII-2 para. 4.17 methods.

2) Investigate if Client has a Design Standard or some Design Criteria for such clamped connections (e.g raise a Technical Query or Memo etc.).

3) Try to "negotiate" with Client some acceptance/qualification Design Criteria - such as to use other Manufacturer's catalogues for allowable loads assumption (such as Galperti or Vector/Techlok), or to employ ASME III-1/NC Para. 3658.3 method for B16.5 bolted flanged joints (e.g. assuming that Clamped Connectors' loading capacity is not lower than B16.5 bolted flanged joint, for similar NPS and Pressure Rate).

I do not see other possible solutions at this time.

Good luck!