Radial Displacement Thin-wall Section (External Pressure Only)

Radial Displacement Thin-wall Section (External Pressure only) Formula
$\Delta_r \;=\; \dfrac{ -\; p_e \cdot r_e^2 \cdot r }{ \lambda \cdot \left( r_e^2 - r_i^2 \right) } \cdot \left( \left( 1 \;-\; \mu \right) + \left( 1 \;+\; \mu \right) \cdot \dfrac{ r_i^2 }{ r^2 } \right)$
Symbol	English	Metric
$\Delta_r$ = Radius Change	$in$	$mm$
$p_e$ = External Pressure	$lbf\;/\;in^2$	$Pa$
$r_e$ = External Radius	$in$	$mm$
$r$ = Radius to Point of Intrest	$in$	$mm$
$\lambda$ (Greek symbol lambda) = Elastic Modulus	$lbf\;/\;in^2$	$Pa$
$r_i$ = Internal Radius	$in$	$mm$
$\mu$ (Greek symbol mu) = Poisson's Ratio	$dimensionless$	$dimensionless$