hi, I should model a 1 inch threaded Victaulic type 730 mechanical tee on a 4 inch header.I used the method # 2 exposed in the question "02. How to model branch fitting (i.e. tee, weldolet, ...) ...".what type of sif should I use in ASME B31J ?!I thought about using:- in point B02 the value of the sif resulting from the calculation by formula of sketch 2.6 of B.31J in the Joint type 6 User SIF (or directly select the "Socket or Fillet Weld" type in the drop-down menu)- the length of the section B02-B03 = length of the nipple of the Victaulic mechanical tee;- in point B03 the I selected Threaded Joint from the drop-down menu.
Is it correct as an approach ?!
Good day to you Mirko,
I had to call Grinnell in order to understand this component (not Victaulic ) According to Grinnell, this type 730 is a rigid coupling that has been modified to accommodate branch connections. Therefore, suggest that you model this as a rigid coupling seen here. Because the 730 coupling has a branch in the middle of the coupling, suggest the following modification:
Flexible joint - short pipe - tee - short pipe - Flexible joint
Note: lengths are based on Grinnell 4x1 type 730 coupling.
With regards to the Tee and SIF topic, I would agree with your approach in using the 2 point tee branch procedure from the aforementioned PDF document. What SIF should be used at the branch connection? You would be correct to use either of the sourced you mentioned earlier in calculating the SIF. It is entirely up to you which one to use. I would suggest evaluating both sources, calculate the both SIF values, and use the conservative value in your model. Or you may decide to use the less conservative. Again, your choice.
Regards,Mike DattilioBentley Product Advantage Group Senior AnalystBentley Systems Inc=============================================================================
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Good day to you Mike,
first of all thank you for your reply and for the investigation with the Grinnell technicians;I take this opportunity to ask you, with respect to the model you have created and attached, some information:1) modeling the coupling as rigid (using a flexible joint) which parameters did you use (axial, torsional stiffness etc.), to take into account that it is a rigid joint? - reading the article you inserted (k. Victaulic / Grinnell grooved fittings ...): what does the phrase "Note: Beam properties, some values cannot be extremely large: (ex. setting modulus as 1e8 in a field that has units of e6, stored value would become 1e14). Setting the modulus value for the rigid to a more reasonable value (say 1000 times steel modulus = 200 E6 N / mm2) resolves the problem "; could you explain to me what you meant?
2) from the colors of your model it seems that: -a) A04-B01 (2.25 "): rigid element (It's right?) -b) B01-B02 (1.44 "): rigid element (purple color)(it's right?) -c) B02-B03 (2 '): branch
3) did you apply the method # 2 of the question "02. How to model branch fitting (i.e. tee, weldolet, ...) ..."?! in the affirmative case: -a) in P.to A04: is the tee type always "other" ?! -b) in P.to B01: have you set a "Joint End Type" (e.g. fitting)? -c) in P.to B02: have you set another "Joint End Type" value (e.g. Threaded)?
Thank you very much for your help.RegardsMirko
Good day Mirko,
To answer your questions:
Q1. 1) modeling the coupling as rigid (using a flexible joint) which parameters did you use (axial, torsional stiffness etc.), to take into account that it is a rigid joint?
Answer: As you know the rigid couling still provides the ability for rotation. Therefore, suggest to set Axial, Shear, and bending to Rigid or more reasonable values, Then in torsion, provide a value that you think is appropriate for Torsional Stiffness. Lastly I accounted for the coupling weight.
Q2. explain to me what you meant?
Answer: On the beam section properties dialog, the modulus value already has a unit of E6 psi. Therefore if you enter a value of 100,000,000, that this would really be 1 e14. Suggest using something a little more reasonable, enter a value of 1000 or 1e9 psi.
Q3. From the colors of your model it seems that x run is rigid?
Answer: Yes, the run from the center of pipe to the outside surface of the header should be rigid, but the pipe from the surface of the header to the end of the fitting, could be either be Rigid or pipe, depends on how yo look at it. I considered the short reinforced section to be rigid. Then the piping from the endge of the coupling on would be regular pipe.
Q4. did you apply the method # 2 of the question "02. How to model branch fitting (i.e. tee, weldolet, ...) ..."?!
Answer: Yes I followed the modeling approach laid out in the document. See Note #2, just before Method #3, to see that I added a length to represent the extra rigid portion of the coupling as mentioned above. Yes, the header tee was set to Other, and sif = 1.0. I also inserted an user SIF at the location where the pipe threaded / grooved to the coupling.
Regards, Mike Dattilio Bentley Product Advantage Group Senior AnalystBentley Systems Inc=============================================================================