关键词: 聚脲, 芳纶纤维, 力学性能, 弹道极限值, 数值仿真

Abstract: In order to enhance and test the fragment penetration resistance of the material structure, the polyurea/fiber aluminum alloy composite protection structure was constructed by spraying polyurea technology with polyurea, aramid fiber and 2024-T351 aluminum alloy materials, and the mechanical properties of polyurea were measured and analyzed. By comparing the protection properties of composite materials under different coating thicknesses and methods, the ballistic limit velocity of different protection structures were obtained, and the failure modes and mechanisms of materials were analyzed. The relationship between coating thickness and protection effect was further studied, and the optimal coating thickness ratio was determined. The results show that the local damage degree of aluminum alloy composite plate coated with 2 mm polyurea /2 mm fiber is small. The ballistic limit velocity of the composite target plate is increased by 96 m/s and the protective effect is increased by 36.64% compared with the uncoated condition. The thickness of the protective coating has limited effect on the ballistic limit velocity. Considering the surface density and material strength, the numerical simulation results show that the optimal thickness of polyurea/fiber coating is 4 mm to 6 mm, and the optimal thickness ratio is 6:4 ratio of polyurea to aramid fiber for the fragmentation resistance of 4 mm aluminum alloy plate.

Key words: polyurea, aramid fiber, mechanical properties, ballistic limit, numerical simulation