TABLE 2-1
CLASSIFICATION OF TRESSES FOR SOME TYPICAL CASES
Vessel
Location
Origin of
Type of Stress
Classification
Component
Stress
Cylindrical Shell plate
Internal
General membrane
Pm
or sphericalremote from
pressure
Gradient through
Q
shell
discontinuities
plate thickness
Axial thermal Membrane
Q
gradient
Bending
Q
Junction with Internal
Membrane
PL
head or flange pressure
Bending
Q
Any shell orAny section
External load General Membrane
head
across entire or moment, or averaged across full
vessel
internal pres-section. Stress com-
sure
component perpendic-
Pm
ular to cross section
External load Bending, across full
or moment
section. Stress com-
ponent perpendicular
Pm
to cross section
Near nozzle or External load Local membrane
PL
other opening moment, or in-Bending
Q
ternal
Peak (fillet or
presssure
corner)
F
Any location
Temp. diff.
Membrane
Q
between shell
and head
Bending
Q
Dished head Crown
Internal
Membrane
Pm
or conical
pressure
Bending
Pb
head
Knuckle or jun-Internal
Membrane
PL[1]
ction to shell pressure
Bending
Q
Flat head
Center region Internal
Membrane
Pm
pressure
Bending
Pb
Junction to
Internal
Membrane
PL
shell
pressure
Bending
Q
Perforated Typical liga- Pressure
Membrane (av. thru
Pm
head or
ment in a uni-
cross section)
shell
form pattern
Bending (av. thru
Pb
width of lig., but
gradient thru plate
Peak
F
Isolated or
Pressure
Membrane
Q
Previous Page
