Page 82 - Pressure Vessel Design Manual
P. 82
General Design 63
th =thickness of head, in.
t, = minimum required thickness of seamless shell, in.
t, =thickness of shell, in.
t,. =thickness of weld joint, in.
t, = minimum distance from outside of head to edge of
weld prep, in.
Z = factor, dependent on d/D ratio
Q, = shear force per unit length, Ib/in.
N, =axial tensile force per unit length, lb/in.
M, =radial bending moment, in.-Win.
u = Poisson’s ratio, 0.3 for steel
b1,2,:3 I = Influence coefficients for head
b4,5,6 i = Influence coefficients for shell
a4,5,6
Formulas
e Circular heads
E
t=d -
e Noncircular heads
2
bs = (-)OS($)
t=dE
where Z = 3.4 - y; < 2.5
e Dirnensionless factors.
Cases
Case 1 (Figure 2-26)
1. C = 0.17 for forged circular or noncircular heads.
2. r 2 3th
3. C = 0.1 for circular heads if
a
= (-)3(1 - U) -
th
a’ = 2(1 - u)
fh
3d(l - U)
a3 =
32t1, Figure 2-26. Case 1 : Flanged head [l , Section UG-34 (a)],
