Good morning to everyone, I ask you the following question:
Why design a hemispherical head using paragraph 4.3.5 (ASME VIII Div.2, 2008a, Part4, paragraph 4.3.5.1, Eq. 4.3.4) does not satisfy the requirements of paragraph 4.3.10 (assumed external loads = 0)?


For example:

P = 15 MPa
D = 2500 mm ==> (Eq. 4.3.4) t = 47,76 mm ==> t adopted = 48 mm
S= 200 MPa


Paragraph 4.3.10

Do = 2596 mm
F = M = Mt = 0
σθm = 199 MPa (Eq. 4.3.35)
σsm = 199 MPa (Eq. 4.3.36)
τ = 0 MPa (Eq. 4.3.37)

σ1 = 199 MPa (Eq. 4.3.41)
σ2 = 199 MPa (Eq. 4.3.42) ==> (Eq. 4.3.44) 203.5 MPa > 200
σ3 = -7.5 MPa (Eq. 4.3.43)


Thank you and regards

These are different methods of calculation, therefore the results can diverge. However, it is good to see that the results are so close to each other.

Michael

Mr Frohnert thank you very much for your answer.
happy new year to everyone.