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#70963 - 02/04/18 12:51 AM Stiffener Arrangement for the Vessel and saddle.
MOHAMMED89 Offline
Member

Registered: 01/22/18
Posts: 8
Loc: Sharjah, UAE
I want to modify an existing vessel, Vessel Length 10m (T/T) And Dia 3.5m.

Saddle analysis is failing since the ending stress at the horn of saddle is failing for the operating case.

I have checked in in the Dennis-R-Moss, And is mentioned that stiffener can be provided to reduce the bending stress.

So i have run the PVElite calculation by proving the stiffener, Now the calculation is passing but i would like to know that the stiffener arrangement as per the attached sketch is acceptable or not.

[url=http://www.eng-tips.com/viewthread.cfm?qid=435088][/url]


Edited by MOHAMMED89 (02/04/18 12:53 AM)

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#70972 - 02/05/18 09:24 AM Re: Stiffener Arrangement for the Vessel and saddle. [Re: MOHAMMED89]
Ray_Delaforce Offline
Member

Registered: 01/02/03
Posts: 703
Loc: Houston, TX
Hello Mohammed89

We do not use the Dennis Moss book for analysis of the stresses in the shell and any rings. PV Elite uses the analysis from ASME Section VIII, Division 2. This has been the case since 2008.
_________________________
Sincerely,
Ray Delaforce
CADWorx & Analysis Solutions
Hexagon PPM

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#70984 - 02/06/18 04:07 AM Re: Stiffener Arrangement for the Vessel and saddle. [Re: Ray_Delaforce]
MOHAMMED89 Offline
Member

Registered: 01/22/18
Posts: 8
Loc: Sharjah, UAE
Dear Sir,

Well noted, I would like to know the arrangement of stiffener on the saddle and near the saddle (for Sketch - http://www.eng-tips.com/viewthread.cfm?qid=435088) is acceptable as per ASME Sev VIII.

Or can you recommend me how to reduce the bending stress.

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#70985 - 02/06/18 06:10 AM Re: Stiffener Arrangement for the Vessel and saddle. [Re: MOHAMMED89]
Ray_Delaforce Offline
Member

Registered: 01/02/03
Posts: 703
Loc: Houston, TX
Hello Mohammed89

Rings can be placed in the plane of the saddle, or alternatively can be placed either side of the saddle. There are some suggestion is ASME Section VIII, Division 2 Figures 4.15.3 and 4.15.4. You will have to try different arrangements until the bending stress is reduced to acceptable limits. We cannot give a rule as to how they should be placed.
_________________________
Sincerely,
Ray Delaforce
CADWorx & Analysis Solutions
Hexagon PPM

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#70986 - 02/06/18 08:01 AM Re: Stiffener Arrangement for the Vessel and saddle. [Re: Ray_Delaforce]
MOHAMMED89 Offline
Member

Registered: 01/22/18
Posts: 8
Loc: Sharjah, UAE
Dear Ray,

Thanks a lot for your advice.

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#70990 - 02/06/18 11:09 PM Re: Stiffener Arrangement for the Vessel and saddle. [Re: Ray_Delaforce]
MOHAMMED89 Offline
Member

Registered: 01/22/18
Posts: 8
Loc: Sharjah, UAE
Dear Ray,

I would like to take your advice for providing three saddles for the vessel. why because.

I have tried the stiffener arrangement for the saddle to reduce the stress and all. but result is still failing. only possibility is change the wear plate of existing saddle with new larger size wear plate. but that is not possible since it is not possible to dismantle the existing vessel from the support.

Please advice me wheather i can introduce new saddle to the vessel. (total will be three saddle).

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#70994 - 02/07/18 07:17 AM Re: Stiffener Arrangement for the Vessel and saddle. [Re: MOHAMMED89]
Ray_Delaforce Offline
Member

Registered: 01/02/03
Posts: 703
Loc: Houston, TX
Mohammed89

PV Elite will allow you to introduce a third saddle support. That is not a problem.
_________________________
Sincerely,
Ray Delaforce
CADWorx & Analysis Solutions
Hexagon PPM

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