Remaining Life of a Pipeline

see apendix # 2), which is resumed in the flow diagram shown in fig. 1
The B31G as most of the available methods is a
deterministic approach which uses nominal values
for the parameters considered in strength and
stress calculation.
fig.1
3. The proposed Physical Model
3.1. Failure Pressure Model
The failure pressure model presented by M. Ahammed is based on the fundamental mechanical
theory of “thin-walled cyilinders”. Cylinders having internal-diameter-to-thickness ratios (D/T) grater
than 10 are usually considered thin-walled cylinders. Pipelines are usually treated as such.
The most important consideration about thin-walled cylinders is that the assumption of constant
stress across the wall results in a negligible error.
The fig.3 shows the acting forces and stresses over a
half of a thin-walled cylinder, and its dimensions:
Sp = circumferential or hoop stress
p = internal pressure
D = pipeline internal diameter
e = unit length
fig.3
T = wall thickness
4