Shear Lug/Trunnion analysis

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aditya0608
Beiträge: 26
Registriert: Mi 28. Mär 2012, 08:15

Shear Lug/Trunnion analysis

Beitrag von aditya0608 »

Hello ROhr Users
Is it possible to analyse the Shear lug / Trunnion connected with pipe with Rohr software?

With Regards
ady
With Regards
Aditya Singh
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rohr2support
Beiträge: 455
Registriert: Mi 14. Sep 2011, 08:23

Re: Shear Lug/Trunnion analysis

Beitrag von rohr2support »

Hi

There is no automatic trunnion analysis in ROHR2 at this time but I have a small Excel-sheet for EN13480-chapter 11 nozzle check
which was created for a publication in the 3R (german piping journal) on Nozzle loads.

Comparison of the design by rules of circular attachments according to
EN 13480-3 clause 11 with a series of analyses using finite elements


The European standard EN 13480-3 “metallic industrial piping” contains in clause 11 an analytic stress calculation of round and rectangular attachments. This calculation is performed by integrating the additional stresses due to the trunnions into the equations for the stresses S1 to S4 of the normal pipe stress analysis. The additional stresses are calculated using stress intensification factors and the load vector at the connection of the trunnion with the pipe. This paper compares the results of the analytic approach to that of a series of analyses using about 75000 finite element calculations of hollow circular attachments.

The idea was to use a finite element series analysis to verify or recalculate the stress intensification factors.

Here is the excel sheet that can be used to calculate either the original EN13480-chapter 11 trunnion analysis or the newly proposed method.
Trunnion_EN13480_Compairison.xls
Best regards
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aditya0608
Beiträge: 26
Registriert: Mi 28. Mär 2012, 08:15

Re: Shear Lug/Trunnion analysis

Beitrag von aditya0608 »

Thanks a lot R2support,

I need one clarification in excel sheet, how to use Rohr2 analysis result in that.
Moreover if you have any calculation for Shear Lugs (Rectangular attachments) , Then provide me.

With Regards
Aditya Singh
With Regards
Aditya Singh
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rohr2support
Beiträge: 455
Registriert: Mi 14. Sep 2011, 08:23

Re: Shear Lug/Trunnion analysis

Beitrag von rohr2support »

Dear R2 user

For the use of the Rohr2 results in the excel sheet for the circular attachments you should proceed like this:
  • create a trunion made of pipe in the ROHR2 model and apply the correct boundary condtitions (e.g. supports at the attachment location)
  • Add a node at the interface between the main run outer diameter and the trunion.
  • Define your load cases and run the calculation
  • Take the results for the bending moments in the run and put them in the excel sheet on page 2 (lines 58-64 colums N+O).
  • Take the results for the attachment point on the trunnion and put them in the excel sheet on page 2 (lines 68-75 colums M+R)
O course you need to fill in the other yellow areas in the excel sheet.

Unfortunately I don't have the same excel sheet for rectangular attachments.

Best regards

Rohr2 Support
aditya0608
Beiträge: 26
Registriert: Mi 28. Mär 2012, 08:15

Re: Shear Lug/Trunnion analysis

Beitrag von aditya0608 »

Thanks alot for your reply.

Regards
Aditya
With Regards
Aditya Singh
pico5892
Beiträge: 2
Registriert: Di 30. Okt 2012, 13:22

Re: Shear Lug/Trunnion analysis

Beitrag von pico5892 »

Dear rohr2support,

Do you have the same excel sheet in english ?

Thanks in advance
best regards
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rohr2support
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Registriert: Mi 14. Sep 2011, 08:23

Re: Shear Lug/Trunnion analysis

Beitrag von rohr2support »

Hi Rohr2 User

Please have a look at the file in the post above, the language is English!

Here is the german version/ Hier ist die deutsche Version :
Nocken_EN13480_Vergleich.xls
Best regards

Rohr2 Support
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pico5892
Beiträge: 2
Registriert: Di 30. Okt 2012, 13:22

Re: Shear Lug/Trunnion analysis

Beitrag von pico5892 »

Thank you,

One question :
Where did you find the allowable loads for the analysis of attachments welded to pipe with a full penetration weld ?
SNT <= 2*ReH
SNT** <= 1.25*fcr
SMT1 <= 0,5*fh

best regards
Marcus
Beiträge: 2
Registriert: Di 12. Mär 2019, 20:25

Re: Shear Lug/Trunnion analysis

Beitrag von Marcus »

Hi,
Thanks for sharing your spread sheet for EN 13480-3 chapter 11!
If you choose "New optimization" where does these formulas for calculate Cw, CL, CN, CT come from? Do you have any reference source to share as well?

(In the calculation for CT for EN13480 (cell AL37 for trunnion and AL42 for the run) the formula for interpolation seems to be incorrect i.e if beta>0.55 the formula shall probably be =IF(AK11<0.55;1;(AK11-0.55)/(1-0.55)*(AO50-1)+1) for AL37) instead of =IF(AK11<0.55;1;(AK11-0.55)*(AO50-1)+1).

Regards
Marcus
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rohr2support
Beiträge: 455
Registriert: Mi 14. Sep 2011, 08:23

Re: Shear Lug/Trunnion analysis

Beitrag von rohr2support »

Hi

The refence is in "3R international" 2010 "Comparison of the design by rules of circular attachments according to
EN 13480-3 clause 11 with a series of analyses using finite elements".

The formulars have been derived based on a series FEM calculation using ROHR2FESU with 75000 FE calculations. Basically all combinations of pipe and trunnions that can be build from standard pipe DN50 to DN2200 were calculated.

Thanks for the hint on CT, I will check the excel sheet.

Best regards

ROHR2 Support
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