Re: Hot Sustained Stress Check

From: <KAUSTUBH>
Date: Fri Apr 18 2003 - 23:30:00 EDT


Dear Harish,
I want to express my views on the following statement:

"in my view u should not ignore small deflection because they will act as constant acting load.... which will cause failure..."

The small deflections will introduce some extra bending stresses in the piping system. Since these are the constant acting loads, they will introduce a static stress in the system. Unless we are not in creep range, the stress will not increase further more to cause failure. The system will be in static equillibrium.

Any more views on this?

Regards,

Kaustubh

>>> toki_harish@yahoo.com 04/17/03 11:06AM >>>
i assume that the meaning of small liftoff means Liftoff by small positive displacement..

Suppose u'r system has three cases
1 operating
2 design
3 Upset
  And in the system u'r two support are going to liftoff ( may be by small displacement ) and due to the removal of these two support u'r system get failed in sustained case ...
What u can do here is just check whether thesse two supports are lifting in the same case or different.. if they lift in different case check for removal of one support at one time...

in my view u should not ignore small deflection because they will act as constant acting load.... which will cause failure...

Rest it will depend upon the project specifications

Regards
Harish

> >>> Rajesh_V_Balapure@ril.com 04/16/03 03:43PM >>>
>
> Generally Hot sustained stress is carried out by
> removing the support at
> the point of lift off ,& check for sustained
> stresses.
> My question is :-
> Is there any guide lines or any proper basis
> available for neglecting
> small lift off for hot sustained stress check.
> If small lift off is allowed to be neglected ,then
> what should be the value
> ??
>
> Regards,
> Rajesh Balapure.
>
>
>
>
>



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Your use of Yahoo! Groups is subject to <a href="http://docs.yahoo.com/info/terms/">http://docs.yahoo.com/info/terms/</a> Received on Fri Apr 18 23:30:00 2003

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