9.1 Introduction

Several papers were published in the last years about hypervelocity impact. It seems that the beginning is a big paper by Al tshuler [1965]; it is a review paper containing everything which was done up to this year (shock adiabats and their experimental registration, methods of obtaining semiempirical equation of state, shock adiabats, speed of sound and isentropic elasticity of shock-compressed bodies, on the composition of the earth s core and the mantle, dynamic strength of materials, etc.). A paper by Alekseevskii [1966] is devoted to penetration of a rod with high velocity; the main ideas and schemes are given an example is computed for the velocity of 1470 m/s. Then is the paper by Tate [1967]. A modified hydrodynamic theory which takes some account of strength effects is used to predict the deceleration of a long rod after striking a target. The results are then compared with experimental data from X-ray observation. The Bernoulli equation is used. The theory of long rod penetration as given in a previous paper is extended by Tate [1969] to take into account of the deformation of a soft rod against a rigid target and the penetration of a rigid projectile into a soft target. It is shown that it is theoretically possible to have a decrease in depth of penetration with increasing impact velocity, and a method for deducing the average radius of the hole is given. The Bernoulli equation is again given for materials which be have as a fluid. A semi-infinite...