A pressurised thin$-$walled cylinder with a mean radius of $2\mathrm{.}0m$ and a wall thickness of $0\mathrm{.}025m$ is made of

a high strength steel with a toughness of $40$MPa$\sqrt[\phantom{2}]{m}$ at room temperature. The alloy has a yield stress of

$450$MPa and a tensile strength of $610$MPa.

An internal semi$-$elliptical edge crack with dimensions $2c=15mm$ and $=8mm$ has been detected in the

cylinder. The crack is very near to a weld that has been given a post$-$weld heat treatment. What is the

critical stress level due to applied pressure?

Choose the one answer that is closest to the correct answer.

$264$MPa

$288$MPa

$340$MPa

$317$MPa

$211$MPa

$232$MPa