I am working on brittle fracture analysis of existing vessel. I am checking all the components of the vessel to see how much temp we can reduce for each component and what could be the lowest temperature we can achieve in accordance with UCS-66 & UCS-67.
I am confused in determining the Coincident ratio (Rst=Stress ratio per API 579).
Rts=S*E*/SE
Where S* = Applied general primary stress = P*(R+0.6*tc)/tc (for shell and Neck)
S = Maximum stress allowable stress value in Tension
E =E* Joint efficiency
P = pressure (Design, start up, ….)
Confusion is, Should I consider Allowable working pressure or Design pressure while Rts = 1.
What is the correct basis?
Thanks a lot!
I am confused in determining the Coincident ratio (Rst=Stress ratio per API 579).
Rts=S*E*/SE
Where S* = Applied general primary stress = P*(R+0.6*tc)/tc (for shell and Neck)
S = Maximum stress allowable stress value in Tension
E =E* Joint efficiency
P = pressure (Design, start up, ….)
Confusion is, Should I consider Allowable working pressure or Design pressure while Rts = 1.
What is the correct basis?
Thanks a lot!