Dear All,
I'd like to know how caesar calculates Von Mises combined stress as per Asme B31.8;
As per Code above, at para. 833.4, combined stress is:
[Sl^2-SlSh+Sh^2]

then, If I have 10" pipeline (restrained),wall thickness=6.35mm, pressure=30bar, temperature =75 C, installation temperature=21 C, we will have:

Sh= PD/2t= 3*273.1/2*6.35= 66.68 N/mm2
Sl= Sb+Se-v*Sh (assumed Sb=0)

Se= E+alpha*DT= 207000*11.7*10^-6*(75-21)= 130.78 N/mm2 (restrained pipe)

Sl= 0+ 130.78- (0.3*66.68)=110.76 N/mm2

Finally, my combined stress will be:

Sc= [110.76^2-110.76*66.68+66,68^2]= 96.58 N/mm2

but Caesar does not show me this value for combined stress, if i check output stress result for OPE case which it considers (pressure+temperature, assuming weight=0)the Max stress intensity is different from my value above?

Can Someone help me? Am i wrong on my calculation?

I realized that I have made a mistake. Expansion stress is compressive while longitudinal pressure stress is tensile. In this case expansion is greater than longitudinal pressure stress, therefore the resultant longitudinal stress value (Sl= Se-vSh)will be compressive, then in the combined stress formula i have to change the sign ( - Sh*Sl) in (plus). Finally the correct value of combined stress will be:

Sc= [110.76^2+110.76*66.68+66,68^2]= 155.25 N/mm2

Caesar shows the max combined stress taken from Von mises or Tresca formulas;
Combined stress for Tresca is: Sh-Se= 66.68-(-110.76)=177.4 N/mm2

and Caesar show me this value.