Mesoscopic analysis on projectile motion characteristics in oblique penetration into concrete

The motion characteristics of projectile during oblique penetration into concrete were studied using a three-dimensional meso-scale model. The finite element model validation and parameter chosen were conducted by comparing the experimental data, with computational efficiency enhanced through improved mesh refinement. Penetration simulations involving deformable projectiles at various incident angles analyzed the effects of aggregate volume fraction and particle size on ballistic trajectory and terminal deflection. Sensitivity analysis reveals a strong power-law relationship between aggregate content and the projectile's deflection angle. The increase in aggregate content will enhance the confinement effect, shorten the intrusion distance of the projectile, and lead to a decrease in the deflection angle of the projectile. The effect of aggregate particle size on the projectile deflection angle follows a Gaussian distribution. The maximum deflection angle occurs when the aggregate particle size is between 2.7 and 3.1 times the projectile diameter. An increase in particle size reduces the number of aggregate-mortar interfaces at the same aggregate volume fraction, leading to an enlargement of the damage zone in concrete, a decrease in the number of cracks, and an increase in crack length. These findings enhance the understanding of concrete penetration mechanisms and offers valuable insights for engineering structure protection.