Effect of the static strength of a metal on long-rod penetration at low velocities

The effect of the static strength (yield stress) of a material on major penetration parameters (specific work of cavity formation and pressure at the contact surface) was examined. The analytical equations and the quantitative evaluation of the specific work spent for the formation of a spherical or cylindrical cavity and of the pressure at the surface of such cavities upon their static expansion were obtained for rigid-plastic and elastoplastic materials. The evaluation of the specific work of deformation upon the formation of the spherical cavity in the plate and the cylindrical one upon the penetration of a rigid rod are shown to be adequate. The influence of strain hardening on maximum radial stresses on the cavity surface was evaluated. The resistance to penetration and the expansion of a cavity are shown to be influenced by the elastic compressibility of a material in the inelastic region. The kinetics of the stress-strain state of the material upon the formation of the cavity was analyzed for the case of considerable deformation of a rod at penetration. © 2000 Kluwer Academic/Plenum Publishers.