RE: EXPANSION STRESS RANGE

From: <NIRMAL>
Date: Wed Oct 09 2002 - 09:40:00 EDT

In thermal loading (self limiting loading case) design allows piping to see yield stress so that the system experiences plastic deformation and develops cold spring within itself.

Now as per code Allowable Stress Sc/Sh = 2/3 Syc/Syh and Sy = 3/2 Sc = 1.5Sc

Because Stress Range is +Sy compression (in hot) to -Sy tension (in cold/ambient)
Sa = 1.5 Sc + 1.5 Sh

After considering safety factors, fatigue and the balance longitudinal stresses this expression is modified to:

Sa = f(1.25(Sc+Sh)-Sl)

The physical significance I understand is to allow piping system to deform in hot condition and built internal stress (like in cold spring).

                       Sachin_Bapat@ril.
                       com                      To:      
PipingDesign@yahoogroups.com
                                                cc:
                       17/09/2002 08:26         Subject:  RE: [PipingDesign]
EXPANSION STRESS RANGE
                       AM
                       Please respond to
                       PipingDesign







Piping code B31.3  gives value of expansion stress range as follows
                       Sa=f((1.25(Sc +Sh) - Sl)

where Sc ,Sh, Sl,f have their usal meaning as defined in code.   My query is
How the code has decided upon this value of 1.25 ? What is the physical significance of this value?
Views are invited from team members on the subject matter. Regards
Sachin Bapat

Texas Flange - a good source for information on industrial flanges, all they ask is for referrals for designs they help with. 877-610-8924.
www.texasflange.com

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Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Received on Wed Oct 09 09:40:00 2002