Trunnion support check calculation
Trunnion support check calculation
(OP)
Dear every piping/stress engineer
1). As per project requirements I need to come up with Trunnion support check calculation to make sure the stress at pipe-trunnion junction point do not exceed hot stress allowable. I also have to validate results produced by the given spreadsheet, developed for this purpose,but not finished.
I know there are some formulae in old Kellogg Piping Engineering Handbook (Cylindrical Attachments to Piping). Does anybody know if there is an access to these recourses in the Internet or just kindly agree to help me with Trunnion support calculation (What checks we want to paeform and what formulae to use).
2). Why do we need to perform this check calculation at all in addition to CAESARII analysis in this software gives us a very good indication of stress levels in the piping system?
Your valuable input will be truly appreciated
Vikoll
1). As per project requirements I need to come up with Trunnion support check calculation to make sure the stress at pipe-trunnion junction point do not exceed hot stress allowable. I also have to validate results produced by the given spreadsheet, developed for this purpose,but not finished.
I know there are some formulae in old Kellogg Piping Engineering Handbook (Cylindrical Attachments to Piping). Does anybody know if there is an access to these recourses in the Internet or just kindly agree to help me with Trunnion support calculation (What checks we want to paeform and what formulae to use).
2). Why do we need to perform this check calculation at all in addition to CAESARII analysis in this software gives us a very good indication of stress levels in the piping system?
Your valuable input will be truly appreciated
Vikoll





RE: Trunnion support check calculation
COADE Pipe Stress Analysis Seminar Notes 2008 cost $250.00
www.coade.com
Caesar II Suer Guide Trunnion • 12-6, 12-8
RE: Trunnion support check calculation
In the past we used whatever design/analysis methodology was available and we did not question the basis of the methodology. It was used "before" and so it was used again. There are better, more well understood methodologies now.
There is a "Kellogg method" for the design/analysis of support trunnions, dummy legs and base elbow supports that was documented many years ago. The document you would find the most helpful in discovering the "Kellogg method" is a series of Kellogg Company in-house design manual notes, "Subject 3810, Design of Piping Attachments - Cylindrical Pipe Attachments, Local Stresses" (13 pages), and Subject 5410,"Horizontal Trunnions" (7 pages). These have been traded around the various Internet discussion forums for years but recent evaluations of these old methods using finite element analysis have found them wanting.
The best approach to analyze these types of constructs is to employ finite element analysis techniques (FEA) by using a software product like FE/Pipe by Paulin Research Group.
Caesar II will serve you well for 90 percent of your piping analysis needs. Caesar II uses beam theory and the ASME B31 Codes for Pressure Piping (including the B31 stress intensification factors - SIF's) to perform structural analyses. However, there are some higher local stresses that B31 methodology and beam theory will not predict. In theses cases (e.g., trunnions and their attaching weldments) you will have to employ FEA to calculated the stresses and you will have to use the ASME B&PV Code, Section VIII, Division 2, to get the allowable stresses to use for comparison. While you are there (Division 2) have a look at the newly codified "structural stress" method of performing fatigue analyses.
Regards, John
RE: Trunnion support check calculation
Q)Question Trunnion support check calculation
A)Trunnion Calculation Sheet (attach)Technaical Note: Purdue University 1975.
There is a "Kellogg method" for the design/analysis of support trunnions, dummy legs and base elbow supports that was documented many years ago. The document you would find the most helpful in discovering the "Kellogg method" is a series of Kellogg Company in-house design manual notes, "Subject 3810, Design of Piping Attachments - Cylindrical Pipe Attachments, Local Stresses" (13 pages), and Subject 5410,"Horizontal Trunnions" (7 pages). These have been traded around the various Internet discussion forums for years but recent evaluations of these old methods using finite element analysis have found them wanting.
L S THILL
RE: Trunnion support check calculation
The well known Kellog Method was adopted into a British Standard publication (restricted distribution)some years back. I have seen many spreadsheets using the Kellog Methods which had interpreted the requirements/procedure incorrectly. For example not considering the total loading on a trunnion but simply checking each load independantly against the allowable stress. There must be a large number of trunnions out there in the wide world which produce stress levels in the pipe which theoretically exceed the Code allowable. It just goes to prove how forgiving steel is!!!
RE: Trunnion support check calculation
"There must be a large number of trunnions out there in the wide world which produce stress levels in the pipe which theoretically exceed the Code allowable. It just goes to prove how forgiving steel is!!!"
Yes and also how conservative our allowable stresses are.
John
RE: Trunnion support check calculation
ADDITIONAL INFORMATION Pipe Trunnion Design
http://norsoftdev.com/trunnion.html
L S THILL
RE: Trunnion support check calculation
visit www.pipemill.com
RE: Trunnion support check calculation
You will get some extremely interesting results if you try to do FE calcs on trunnions and then compare them with Kellogg. You should try a single trunnion - header combination and then apply different loads / arrangements of the header. i.e. Not just a nominal few diameters of straight header with varying loads applied to the end of the trunnion. As DSB123 says "It just goes to prove how forgiving steel is!!!"
RE: Trunnion support check calculation
Not that it necessarily applies to any to the references above but questionable methodology is still questionable methodology even if it is automated.
John.
RE: Trunnion support check calculation
Does this method provide consistent results which is good enough for piping design objectives or it is worth time and efforts to do the check using FEA software?
What SIFs would you recommend to use in SAESARII for the trunnion and dummy support from the elbow?
Thanks and have a great day
Vikoll
RE: Trunnion support check calculation
See attach "I would also like to see some comparison to FEA results"
Also, ASME technical verification & validation for FE-pipe & Nozzle Pro. contact Tony Paulin.
Stephen
L S THILL
RE: Trunnion support check calculation
Wen you say "Budlong" are you refering to Lynwood A. Budlong of Stone & Webster Engineering Mechanics fame...??
As I understand and recall, Budlong (and others) developed an in-house methodology and guideline on this particular topic that was eventually adopted by the USNRC.
I remember eating subs and chips on Boston Commons with Budlong....why....I even remember when he had hair !!!!
-MJC
RE: Trunnion support check calculation
I would guess its the same person. Definitely Stone and Webster. It will be good to see what these guys are producing with current tools.