Influence Of Sandwich Back-plates On Ballistic Performance Of Ceramic Composite Armor And Numerical Simulation

In recent years, protective armors resisting the high speed projectile’s penetration have become a hot research topic in the fields of modern military and national defense. However, it’s very important to know how to improve the defense ability, at the same time to reduce the weight of the equipment.In this thesis, several kinds of ceramic composite armors were tested against the 12.7 mm armor piercing projectile at a velocity of 818 m/s. The penetration process of the projectile and the bulletproof mechanism of the ceramic composite armor were systematically investigated, aiming at improving the protective coefficient and realizing the lightweight armor design.The alumina ceramic particles, being substantially cylindrical in shape, were arranged in a plurality of adjacent rows and columns, connected with each other by silicone rubber. Combining with the sandwich composite back-plates, the whole armor was tested with the 12.7 mm projectile’s vertical impact, revealing the bulletproof mechanism of the cylindrical ceramic layer and the energy dissipation mechanism of the stress wave propagation. Compared with a monolithic ceramic plate,such ceramic layer cannot only reduce the fractured zone, but also quickly repair the fractured zone by filling new cylindrical ceramics with silicon rubber. According to the Military Standard(GJB/59.18-1988), five kinds of ceramic composite armors were measured. By contrastively analyzing the damage results, the armor structure of Al2O3/TC4/UHMWPE/TC4 had the lowest damage level, and its areal density was only 83.0 kg/m2 while the protective coefficient was as high as2.98, realizing the lightweight design and preventing the projectile’s perforation.The penetration process was simulated with the software of ABAQUS/Explicit, and then the postprocessing results such as distribution of stress contour, velocity variation of the projectile, energy absorption of each layer were obtained. Comparing with the influence of the different sandwich composite back-plates on the ballistic performance under the conditions of same materials and thickness, and the influence mechanism of the different third back layer on the penetration results under the condition of same areal density, it was indicated that the sandwich composite back-plates TC4/UHMWPE/TC4 could effectively defeat the residual velocity of the projectile, and the middle UHMWPE layer had an energy balance function between the first and outermost TC4 layers to cause small damage in the back laminate layers. Meanwhile, the third TC4 layer provided support for the UHMWPE layer, leading to the UHMWPE layer displaying the extremely high buffer performance during the impact process.Due to the uncertain impact sites of the projectile in experiment, it still needs to analyze with the numerical simulation technique. It can be divided into three possibilities describing the projectile’s impacting sites on the arranged ceramic particles. The simulation results show that it would cause overall breakage(case 1) or partical fragmentation(case 2 and 3), however, it can still prevent the penetration of the projectile in case 2 and 3, because of much more direct contact number of ceramic particles with the projectile. In other words, no matter which site the projectile impacts on, the composite armor can effectively defeat the vertical impact of the projectile at the velocity of 818 m/s.