SIMILARITY LAWS OF HYPERVELOCITY PENETRATION EFFECTS OF CONCRETE¹⁾

To study the similarity laws of the hypervelocity penetration effects of concrete, the basic theories of similarity laws are firstly reviewed briefly, and the hypervelocity penetration experiments of concrete are conducted in the velocity range from 1.4 km/s to 3.9 km/s. According to the experimental results of this study and those in the related literature, the principal similarity criterions are obtained, and the normalized penetration depth is determined by data fitting. It is shown that the normalized penetration depth mainly depends on the Johnson number, the mass density ratio of the projectile to the target and the length-diameter ratio of the projectile, while weakly depends on the strength ratio of the projectile to the target and the nose-shape coefficient of the projectile. The normalized penetration depth firstly increases and then decreases with the increase of the normalized impact velocity, with a sudden drop when the impact velocity is close to the P-wave velocity of concrete, which is named as the “transonic speed effect”.