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#46614 - 01/08/12 06:19 AM Temperature reduction factor A1- in ISO14692 for GRE lines
learner2011 Offline
Member

Registered: 01/14/11
Posts: 91
Loc: india
Hi everyone,
why does the Caesar always take
Temperature reduction factor,A1=1 when it calculates the sustained stress allowable for hoop and axail stress irrespective of the value of A1 used in input.
Even if i change A1=0.5 the sustained stress allowbles remain same.
While as per ISO14692,A1 is directly involved in stress calculation.
Can anyone explain this devation from ISO or there is a reference in ISO to use A1 =1 for sustained case.
Waiting for your feed back

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#46664 - 01/10/12 09:06 AM Re: Temperature reduction factor A1- in ISO14692 for GRE lines [Re: learner2011]
Dave Diehl Offline
Member

Registered: 12/14/99
Posts: 2382
Loc: Houston, TX, USA
A different interpretation of the Code is currently implemented in CAESAR II - A1 is not part of the allowed limits for what we call sustained stress.
If you wish to include A1 in CAESAR II's (SUS) load case, a thermal case must be included. For example, rather than running W+P1(SUS), specify W+P1+T2(SUS) where A1 for T2 is set to the value you want to use. The trick is that you do not want any thermal strain from T2 in the weight plus pressure analysis. To accomplish this, set T2 to a value very close (but not equal to) ambient temperature, or, use a very small scalar multiplier with that T2; e.g. W+P1+0.0001T2(SUS).
I hope this is not too confusing.
Because of your post, we are re-evaluating our position on the application of A1 in "(SUS)" case for ISO 14692. Thank you.
_________________________
Dave Diehl

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#46793 - 01/17/12 04:53 AM Re: Temperature reduction factor A1- in ISO14692 for GRE lines [Re: learner2011]
learner2011 Offline
Member

Registered: 01/14/11
Posts: 91
Loc: india
Thanks for your reply and solving the issue.
One more issue.
I am doing Time-history analysis for GRE piping using ISO-14692 .
The problem is Caesar does not show allowable stress values when I check the stresses for combination of dynamic and sustained load. While as in ASME 31.1 I was able to see the allowable in the same load combination. Can you please help to solve this discrepancy.You can see in below screen shot and attached document allowable are 0


Attachments
Dynamic Output.pdf (315 downloads)
dynamic output.JPG



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#46811 - 01/17/12 11:25 AM Re: Temperature reduction factor A1- in ISO14692 for GRE lines [Re: learner2011]
Dave Diehl Offline
Member

Registered: 12/14/99
Posts: 2382
Loc: Houston, TX, USA
Presently, CAESAR II does not provide ISO 14692 allowable stresses in the dynamics processor.
_________________________
Dave Diehl

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#46832 - 01/19/12 03:08 AM Re: Temperature reduction factor A1- in ISO14692 for GRE lines [Re: learner2011]
learner2011 Offline
Member

Registered: 01/14/11
Posts: 91
Loc: india
Thank you Sir for sharing these vital facts about Caesar and ISO-14692.
Any plans from Intergraph to update Caesar so that these comments are updated.
Once again thanks Sir

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#46858 - 01/19/12 05:33 PM Re: Temperature reduction factor A1- in ISO14692 for GRE lines [Re: learner2011]
Richard Ay Offline
Member

Registered: 12/13/99
Posts: 6226
Loc: Houston, Texas, USA
Of course - it is just a matter of time and resource allocation.
_________________________
Regards,
Richard Ay - Consultant

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