#54690 - 05/31/13 10:50 PM
why thermal stress is not considered in circum. direction
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Member
Registered: 06/18/12
Posts: 345
Loc: India
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Hello Everyone,
If pipe size is large, temperature more. At anchor point why Caesar not considering circumferential stresses due to temperature.
What is the Basis for neglecting that stresses???
please respond.
_________________________
Thanks,
Durga
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#54695 - 06/01/13 08:36 AM
Re: why thermal stress is not considered in circum. direction
[Re: durga]
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Member
Registered: 12/13/99
Posts: 6226
Loc: Houston, Texas, USA
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The typical flexibility analysis (B31.1/B31.3) addresses "longitudinal stresses" only.
_________________________
Regards, Richard Ay - Consultant 
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#54705 - 06/02/13 07:20 PM
Re: why thermal stress is not considered in circum. direction
[Re: durga]
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Member
Registered: 01/21/06
Posts: 32
Loc: malaysia
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Dear Mr.Richard,
As per expansion stress case we allow for local yielding of pipe. In that case is there any allowance taken care for thickness calculation for circumferential stresses.
Regards,
_________________________
arajagopal
knowledge is power
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#54777 - 06/05/13 11:55 PM
Re: why thermal stress is not considered in circum. direction
[Re: durga]
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Member
Registered: 12/13/99
Posts: 6226
Loc: Houston, Texas, USA
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No.
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Regards, Richard Ay - Consultant
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#54805 - 06/07/13 12:39 AM
Re: why thermal stress is not considered in circum. direction
[Re: durga]
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Member
Registered: 01/21/06
Posts: 32
Loc: malaysia
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In FPSO's there are expansion load cases which is considered for towing
because of structural displacements. If there is an yielding in pipe as allowed in expansion case and if the pipe is hydrotested after towing will there not be failure at the point where the pipe yielded.
Regards,
_________________________
arajagopal
knowledge is power
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#54913 - 06/11/13 11:27 PM
Re: why thermal stress is not considered in circum. direction
[Re: rajagopal]
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Member
Registered: 01/21/06
Posts: 32
Loc: malaysia
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Dear Experts,
Waiting for your valuable comments.
Regards,
_________________________
arajagopal
knowledge is power
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#54915 - 06/11/13 11:37 PM
Re: why thermal stress is not considered in circum. direction
[Re: durga]
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Member
Registered: 06/18/12
Posts: 345
Loc: India
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Dear All,
I think in underground piping, this circumferential stresses due to temperature may cause huge impact on the pipe.
May be low temperature, but the expansion due to temperature is completely restricted.
Then what is the reason flexibility analysis (B31.1/B31.3)addresses "longitudinal stresses" only Due to temperature.
_________________________
Thanks,
Durga
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#54980 - 06/16/13 09:40 PM
Re: why thermal stress is not considered in circum. direction
[Re: durga]
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Member
Registered: 06/18/12
Posts: 345
Loc: India
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Dear RICHARD, Can u please clarify this doubt..
I think in underground piping, this circumferential stresses due to temperature may cause huge impact on the pipe.
May be low temperature, but the expansion due to temperature is completely restricted.
Then what is the reason flexibility analysis (B31.1/B31.3)addresses "longitudinal stresses" only Due to temperature.
_________________________
Thanks,
Durga
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#54999 - 06/17/13 06:26 PM
Re: why thermal stress is not considered in circum. direction
[Re: durga]
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Member
Registered: 12/13/99
Posts: 6226
Loc: Houston, Texas, USA
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If you're running B31.4 or B31.8, then the hoop stress is included in the Code Stress equations. These are the Codes you should be using for buried piping.
B31.1/B31.3 address unrestrained (above ground) piping, and consider longitudinal stresses (look at the equations).
_________________________
Regards, Richard Ay - Consultant
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#55002 - 06/17/13 06:58 PM
Re: why thermal stress is not considered in circum. direction
[Re: Richard Ay]
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Member
Registered: 01/21/06
Posts: 32
Loc: malaysia
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Dear Mr.Richard,
In FPSO's there are expansion load cases which is considered for towing because of structural displacements. If there is an yielding in pipe as allowed in expansion case and if the pipe is hydrotested after towing will there not be failure at the point where the pipe yielded.
Regards,
Edited by rajagopal (06/17/13 06:59 PM)
_________________________
arajagopal
knowledge is power
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#55003 - 06/17/13 09:12 PM
Re: why thermal stress is not considered in circum. direction
[Re: durga]
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Member
Registered: 06/18/12
Posts: 345
Loc: India
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ok
Thank you RICHARD
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Thanks,
Durga
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