Longitudinal Stress Thick-walled Section (External Pressure Only)

Longitudinal Stress Thick-walled Section (External Pressure Only) Formula
$\sigma_l \;=\; \dfrac{ - p_e \cdot r_e^2 }{ r_e^2 - r_i^2 }$
Symbol	English	Metric
$\sigma_l$ (Greek symbol sigma) = longitudinal stress	$lbf\;/\;in^2$	$Pa$
$p$ = external pressure	$lbf\;/\;in^2$	$Pa$
$r_e$ = external radius	$in$	$mm$
$r_i$ = internal radius	$in$	$mm$