Functionally-graded cementitious panel for high-velocity small projectile

Abstract

A functionally-graded (FG)-cementitious panel to resist high-velocity small projectile penetration was developed. First, a ductile hybrid cementitious laminate reinforced with short-discontinuous polyethylene (PE) fibers and closely-spaced steel mesh (known as PE-fibrous ferrocement) was designed and studied for its energy absorption property, tensile strength and ultimate strain capacity, including strain-rate effects. This material forms the outer ductile top and bottom layers of the FG-panels, infilled with a thin calcined bauxite aggregate layer to provide penetration resistance followed by conventional concrete forming the remaining thickness. To investigate the impact resistance of these FG-panels, 72 specimens (200x200x100mm) were fabricated and impacted with ogive-nosed projectiles at velocities ranging from 300-600m/s. In addition, three-dimensional numerical models of the FG-panels subjected to projectile impact were also developed using LS-DYNA. The numerical results compared favorably in terms of penetration depths and crater diameters observed experimentally and the model was subsequently used for parametric study and design optimization.