A dimensionless parameter, i. e., the damping function was introduced, besides, the impact function I, geometry function N and dimensionless target thickness χ of projectile had been introduced previously. With accounting for viscous effect and dummy mass of projectile, the normal perforation of thick metallic plate struck by sharp nose rigid projectile was further studied and only I, N and ζ as well as the dimensionless target thickness χ dominated in perforation. The influence of damping function ζ on perforation was discussed in detail. Theoretical prediction of penetration and perforation in present manuscript shows good agreement with the individual published test data of different projectile and impact velocity as well as different target.