Influence of the mushroomed projectile's head geometry on long-rod penetration

• Published in: International journal of impact engineering Vol. 148; p. 103769
• Main Authors: Jiao, W.J., Chen, X.W.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2021; Elsevier BV
• Subjects: Alekseevskii-Tate model; Antiballistic materials; Ballistic penetration; Cavity expansion; Diameter ratio of rod nose and shank; Impact velocity; Kinetic energy; Long-rod penetration; Nose geometry; Nose shape effect; Nose shape factor; Penetration; Projectiles; Radial flow; Shape effects; Shape factor; Sharpening; Sharpness; Terminal ballistics; Long-rod penetration; Nose shape factor; Diameter ratio of rod nose and shank; Alekseevskii-Tate model; Nose shape effect
• ISSN: 0734-743X; 1879-3509
• DOI: 10.1016/j.ijimpeng.2020.103769

•A 2D model of long-rod penetration is established by constructing the function of nose shape and determining the resistance of rod nose. The diameter ratio of nose and rod η and the nose shape factor N* are two main parameters which can represent nose geometry during the hypervelocity penetration process in the 2D model.•The effects of η and N* on long-rod penetration and their mechanisms are analyzed in the case study. The effect of the nose shape factor on penetration velocity, penetration time and penetration depth is evidently smaller than that of the diameter ratio, which is the possible reason for only introducing η to reflect the effect of nose shape in the previous sketchy 2D models.•The value of the diameter ratio η represents the extent of the radial flowing of rod material, thus the physical essence of 2D characteristic can be correspondingly explained. Self-sharpening has been observed in experiments and simulations of long-rod penetration. Penetration performances are influenced by different nose shapes occurred in the penetration of long rods made by different materials. In this paper, to model this nose shape effect, the resistance of the target in the standard Alekseevskii-Tate model is replaced by the resistance determined by the spherical cavity expansion approximation for general nose shapes. The function of nose shape is constructed to establish a modified model of long-rod penetration, in which the nose geometry during the long rod penetration is represented by two main parameters, i.e., the diameter ratio of rod nose and shank η and the nose shape factor N*. The influences of η and N* on long-rod penetration and their mechanisms are analyzed. The penetration performance decreases with an increasing diameter ratio η, whose physical basis is the increased radial flow of rod material around the nose, which in turn, leads to the loss of kinetic energy due to larger cavity formed in the targets. The nose shape factor N* reflects the sharpness of nose shapes, and a smaller value of N* corresponds to a sharper nose. N* obviously affects the ballistic performance of long-rod penetration, however, depending on the initial impact velocity. In general, the influence of N* is relatively smaller than that of η.