Equivalent diameter between screen/sheath and armour.

Symbol
$d_{\mathrm{e}}$
Unit
mm
Formulae
$\sqrt{\frac{d_{\mathrm{a}}^{2}}{2} + \frac{d_{\mathrm{s}}^{2}}{2}}$
Related
$d_{\mathrm{a}}$
$d_{\mathrm{s}}$
$\lambda_{\mathrm{1es}}$
$X_{\mathrm{s}}$