allowable stress

Hi Pipers,
Can anybody tell me which type of stress(i.e.,axial,radial,Hoops stress) in thickness calculation.


t = PD/2(SE+PY)

S = Allowable stress,
i mean 'S' is which type of allowable stress .


10Q in advance.

Regards,
S.Manjula.

Circumferential (or) hoop stress (SH) = PD/2t

Axial (or) Longitudinal Stress (SL)= PD/4t

The radial component is negligible as compared to the other two Component (SH and SL).

from the above equations you can figure out, which stress are you using for thickness calculation.

S. Manjula,

I do hope you are NOT a Caesar II user.

You asked:

S = Allowable stress,
i mean 'S' is which type of allowable stress .

In the equation you quote it's the allowable stress in tension at the design temperature, taken from Appendix A of ASME B31.3 or similar. It is different for various materials and reduces with increasing temperature.

Hi manjula
As MoverZ mention S is allowable stress of piping material ( isotropic material)( B-31.3 or other code) in tension in any direction.
Above thickness calculation formula is based on calculated hoop stress since it is most critical one for thickness calculation.

Hi
what are the difference in radial and axial load?
In caesar 5.1, after the analysis and then verfiy the result based on restraint summary..in that to check the nozzle allowable.client allowable nozzle load mention like axial force, single shear force, resultant shear force, torsional moment, single moment and resultant bending moment.but in caesar 5.1 shows only fx,fy,fz,mx,my and mz. how i related to client allowables?

by srini

Hi Shabber
Cross check your vendor document they mention force ( axial , longitudinal & circumferential ) & moment ( tortional, longitudinal & circumferential). Generally sketch is attached to indicate the direction also in allowable nozzle load document.

Then compare that data with Caesar global force & moment Fx, Fy, Fz, Mx, My & Mz.

In case of skew nozzle take local element force & moment fx,fy,fz,mx,my and mz to compare with vendor data. To check direction for local element follow Caesar manual.

hi shr

no they mention axial, single shear, and resultant shear force only. what thier mention single shear and resultant shear force?

single shear means longitudinal force
resultant shear force means circumferential how?
its diffcult to understand can u explain....

thank for ur reply.....

Hi Shabber

I guess they have same value for longitudinal & circumferential direction each of which refer as single shear force. Resultant of that two as resultant shear force.

can you attached your vendor data here or send it to me habibur21@gmail.com