Constitutive modelling of concrete material subjected to low-velocity projectile impact: insights into damage mechanism and target resistance

This paper presents a numerical study to improve the understanding of the complex subject of penetration and perforation of concrete targets impacted by low-velocity projectiles. The main focus is on the damage mechanisms and the major factors that account for the target resistance of the concrete. An improved continuous surface cap model recently proposed was employed. The model was first equipped with element erosion criteria and was adequately validated by comparisons with ballistic experiments. Comprehensive numerical simulations were carried out where the individual influence of tensile, shear, and volumetric behaviors (pore collapse) of a concrete target on its ballistic performance was investigated. Results demonstrated that cratering on the front face and scabbing on the rear face of the concrete target were mainly dominated by its tensile behavior. The major target resistance came from the second tunneling stage which was primarily governed by the shear and volumetric behaviors of the concrete. Particularly, this study captured the pore collapse-induced damage phenomenon during the high-pressure tunneling stage, which has been extensively reported in experiments but has usually been neglected in previous numerical investigations.