Page 241 - Pressure Vessel Design Manual

Special Designs 219

tension stresses due to pressure are combined with local
Notes bending stresses. This stress may be as high as 2.04 times
the hoop stress in a simple, unstiffened shell of like size. The
A stiffening ring bending stresses in stress is local and fades rapidly with increasing distance from
the shell immediately adjacent to the ring due to differential he ring. This procedure stiffening rings are spaced
deflection between the and ring. The is greater than n/p so effect from adjacent rings is insignificant.
highest at the inner surface of the shell where longitudinal

PROCEDURE 4-4

TOWER DEFLECTION 171

Notation
L = overall length of vessel, in.
L, =length of section, in.
E, = modulus of elasticity of section, $si
I, = moment of inertia of section, in.
W, =concentrated loads, Ib
w = uniformly distributed load, Ibhn.
w,, = uniformly distributed load at top of vessel, lbhn.
wmi, =uniformly distributed load at bottom of vessel, lb/
in. I c=/ I
X = ratio L,/L for concentrated loads
6 =deflection, in.

Cases

Case 1: Uniform Vessel, Uniform Load
Case 3: Nonuniform Vessel, Nonuniform Load
a=- wL4
8EI
Case 2: Nonuniform Vessel, Uniform Load

0 If E is constant

0 IfE is not constant