Study on ballistic mechanism of B₄C/Al gradient armor

In order to improve the anti-penetration performance of gradient armor, the constitutive models of B4C/Al composites with different compositions were determined according to the bending curves. The anti-bullet simulation of B4C/Al gradient armor was carried out by ANSYS-DYNA finite element software, and the stress state of B4C/Al gradient material under 7.62-mm bullet penetration was analyzed. Meanwhile, the propagation law of stress wave in armor was studied by Hopkinson bar simulation and the improved internal stress wave model, which further revealed the ballistic mechanism of B4C/Al gradient armor. The simulation results showed that, compared with the traditional laminated armor, the toughness of B4C/Al gradient armor material increased with the change of layer thickness, resulting in the fact that the whole armor could withstand greater stress without breaking, and the anti-penetration time was prolonged. In addition, the performance difference between the layers of the gradient armor was slight, and the spallation phenomenon of the relative double-layer armor decreases, which enhanced the multiple hit performance of the armor and the absorption capacity of the stress wave. The performance of B4C/Al gradient armor specimens and double-layer specimens were tested by drop hammer impact test. The test results were consistent with the simulation results.