Ballistic Textiles
V50 rises with the square root of areal density, so every extra 10 m/s costs more plies than the last did. That curve is the whole design problem.
— m/s
Velocity at which half the strikes would perforate
Decision-support only, and not a certification tool. Real V50 depends on the exact threat, obliquity, backing material, pack stitching, conditioning and ageing, and the relationship is only linear over a limited ply range. Life-safety armour must be ballistically tested to the governing standard — never fielded on a calculated figure.
Ballistic Aramid Plies to V50 Velocity Modeler — free, with the formula and a worked example, at Textile School.