关键词: 复合材料, 三维深角联, 织物纬密, 组织结构, 铺层方式, 弯曲性能, 芳纶织物, 环氧树脂, 真空辅助成型工艺

Abstract:

Objective In order to reduce casualties and improve the overall protection performance of vehicles in warring areas, the protection requirements of composite materials for bullet-proof vehicles are getting higher. Aramid three-dimensional deep-angle interlock (3DDAI) and plain weave fabrics are used as reinforcement materials, and epoxy resin is used as the matrix. The influences of weft density, structure organization and laying method on bending properties of composite materials for armored vehicles are studied.
Method In order to explore the influence of fabric weft density, structure organization and laying method on the bending properties of aramid fabric/epoxy resin composites, 250 mm×250 mm aramid fabric (The warp and weft linear densities of the fabrics are both 111.1 tex is used. For the plain weave fabric, the warp and weft densities are both 10 picks/cm. For the three types of 3DDAI fabrics, the warp density is consistently 30 picks/cm, with weft densities of 30, 33, and 36 picks/cm, respectively, as the reinforcement, epoxy resin E-51 and curing agent polyether amine 230 are used as the matrix. The composite was manufactured using vacuum assisted resin infusion, and the samples under various influencing factors are tested and analyzed on the Instron 5969H universal material testing machine.
Results When the 3DDAI aramid fabric/epoxy resin composite material is subjected to bending load, the bending performance in the weft direction is superior to that in the warp direction. With the increase of weft density, the bending strength and modulus in the weft direction and the bending modulus in the warp direction of the material all show a trend of increasing first and then decreasing, while the bending strength in the warp direction shows a decreasing trend. Moreover, the bending strength in the warp direction of aramid fabric/epoxy resin composites is negatively correlated with the warp buckling degree. The bending strength and modulus in the weft direction of the three-dimensional deep angle interlock composites are better than those of the plain weave, and the bending strength and modulus in the warp direction are smaller than those of the plain structure. The bending strength in the warp direction of aramid fabric/epoxy resin composites prepared by orthogonal laying method (0°/90°/0°/90°) is 257.049 1 MPa and the bending strength in the weft direction is 242.579 0 MPa, indicating that the laying method is beneficial to maximize the potential of improving the bending properties of materials and reduce the difference in bending performance between materials in different directions.
Conclusion When the 3DDAI aramid fabric/epoxy resin composite bears the bending load, the bending properties of the sample show the longitude and latitude anisotropy, in which the bending properties in weft direction are greater than the warp direction. With the increase of weft density, the bending strength in weft direction, bending modulus in weft direction and bending modulus in the warp direction of 3DDAI composites increase first and then decrease, while the bending strength in the warp direction decreases, with the best bending properties when the warp density of the fabric is 30 picks/cm and the weft density is 33 picks/cm. The in weft direction bending properties of 3DDAI aramid fabric/epoxy resin composite are better than that of plain weave, and have better delamination resistance. The properties of aramid fabric/epoxy resin composite material by orthogonal laying method are conducive to maximize the potential of improving the bending performance of the material, while reducing the difference in bending properties between different directions of the material.

Key words: composite material, three-dimensional deep angle interlock, weft density, structural organization, laying method, bending property, aramid fabric, epoxy resin, vacuum assisted resin infusion