Hello All,

I'm kinda confused by these qustions. Does CESAR consider hoop stress anywhere? and if not, then how can it use the maximum shear stress method for primary load allowables?

another issue is that ASME B31.3 defines SL
Thanks a lot

B31.3 does not include the hoops stress in its Code Stress equations (SL and SE). The consideration of hoop stress is used in the determination of the minimum pipe wall thickness.

Thanks Richard,

Hi

As per Max Shear stress theory
(S1-S3)/2 = Sy/2 (assume S2=0)

where S1 is Longitudinal stress,S3 is radial stress (S2 we are not considering as you said it is already considered for thickness calculation)
here is my doubt-As per our code equation for Sustain stress we are considering only Longitudinal stress no radial stress.then how could we say that code equation is based on max shear stress theory?


Regards
SB

Mr Rechard
Please clarify my doubt

Regards
SB

It is reasonably accurate to assume that the magnitude of the radial stress is so small in comparison with the hoop and longitudinal stresses that it can be neglected.
In practice it will vary from zero at the outside surface to a value equal to the internal pressure at the inside surface. You may compare yourself the numerical values.

And also there is another question that as per ASME B31.3 sustained stresses are calculated as :

SL= [(Sa+Sb)^2 + 4St^2]^1/2

but if I'm not wrong CAESAR II is using the sum of all longitudinal stresses which means:

SL= Sa+Sb+Sp

then torsional stress is not considered in this equation and it doesn't conform with code equation.

regards

Maybe, it depends on what version of CAESAR II you're running. Remember, B31.3 only recently provided that equation. Prior Editions of the Code just verbally stated what SL meant.

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http://65.57.255.42/ubbthreads/ubbthreads.php?ubb=showflat&Number=230

Thanks a lot