Experimental study on high-speed penetration of reinforced concrete targets by structural projectiles made of two types of materials

Two kinds of structural projectiles made of two different materials were designed in this paper. An experimental study of 11 kg projectiles penetrating the reinforced concrete target at 1400 m/s was carried out using a 203 mm Davis gun. Based on the experimental results, the structural response, penetration capability and related engineering issues of the projectile are discussed. The results show that when the reinforced concrete target is penetrated at a velocity of 1400 m/s, the heads of projectiles made of two different materials experienced erosion and were mushroomed. This was caused by high temperatures resulting from friction between the projectile and the concrete during penetration, which significantly softened the surface of the projectile. Furthermore, the contact pressure between the projectile and the target exceeded the yield strength of the projectile material near the surface, causing the material to enter a state of plastic flow and ultimately leading to the erosion and mushrooming of the projectile head. Additionally, the surface material of the projectile was stripped due to the cutting action of the hard aggregates in the concrete, resulting in severe abrasion of the projectile body. When comparing the structural responses of projectiles made of different materials, it was evident that material properties influenced their behavior. Compared to 30CrMnSiNi2MoVE, DT1900, known for its higher strength, hardness and better resistance to impact compression, showed less erosion at the projectile head. However, the inferior shear resistance and wear resistance of DT1900 led to severe abrasion on the projectile body. The mass loss pattern of a conical projectile is different from that of a solid long-rod projectile, with the latter concentrated mainly in the projectile body. The conical flared tail design, while suppressing ballistic deflection, increased the contact area between the projectile body and the target, enhancing the abrasive and cutting actions of aggregates and steel. Moreover, under high-speed penetration conditions, the erosion and mushrooming of the projectile head could reduce the penetration depth; the less erosion at the head, the greater the penetration depth. In experiments, the maximum penetration depth of DT1900 projectiles could reach up to nine times the length of the projectile.