Experimental and numerical investigation on projectile penetration resistance of a composite material made of granite rubble and UHPC

Composite bursting layer made of rock rubble and cementitious matrix has good penetration resistance and superior cost-effectiveness. However, the anti-penetration mechanism of this composite material is still not well understood. A combined experimental and numerical investigation of the anti-penetration mechanism of a composite material composed of granite rubble and ultra-high-performance concrete was carried out in the present study. Firstly, a test of projectile penetration into the composite target was conducted, which provided valuable data including the penetration depth, frontal crater dimension and cross-sectional damage in the composite target. Then, a corresponding numerical model was established based on the random distribution algorithm, Kong-Fang material model and SPG algorithm, which was validated against the conducted penetration test. The validated numerical model was finally used to investigate influences of granite-rubble size, volume fraction, and material strengths on the penetration resistance of the composite targets. Numerical results demonstrated that enhancing penetration resistance of the composite target can be achieved by optimizing rock-rubble size, increasing the strengths of constituent materials, and reducing the volumetric fraction of rock rubble. Corresponding suggestions were given for engineering use as to balance the penetration resistance and cost.