Abstract:

Threedimensional (3D) textile composites with threedimensional fabrics as the reinforcing phase and the presence of reinforcing yarn in the thickness direction overcome the shortcomings of traditional laminated composites with poor interlaminar bonding and easy delamination damage, and have unique advantages such as high specific strength, high specific independence, excellent designability, impact resistance and fatigue fracture resistance. These materials are currently receiving increasing attention in the field of impact protection such as aerospace and rail transportation. However, the study of structural effects, strain rate effects and characterization of damage processes during high speed impact loading of 3D textile structural composites is still immature and needs to be further explored so as to design 3D textile structural composites with better impact resistance.

In order to investigate the strain rate effect and structural effect of threedimensional textile structural composites under highspeed impact, we prepared the 3D braided and 3D angleinterlock carbon fiberreinforced epoxy composites using vacuumassisted resin transfer molding process. The stressstrain curves and progressive damage processes of 3D braided and 3D angleinterlock composites during highspeed impact were recorded by a modified separated Hopkinson compression bar system and highspeed photography system. On this basis, the article investigates the structural and strain rate effects of the highspeed impact performance the progressive damage process of 3D structural composites. The results show that both braided and angleinterlock composites have strain rate effect under highspeed impact, and both show shear damage, but the braided composites show obvious ductile damage while the angleinterlock composites show obvious brittle damage. Because of the tightly interwoven fiber bundles inside the braided composites, they can still withstand certain loads and maintain structural integrity after damage, so the 3D woven composites have better impact resistance than the 3D angleinterlock composites.

During high speed impact, there are obvious structural and strain rate effects on the high speed impact performance and the progressive damage behavior of 3D textile structure reinforced composites. Exploring the high speed impact response of different 3D textile structure composites can provide insight into the design of composite materials for aerospace and rail transportation, expand the application fields of 3D textile structure composites, and promote the development of material design for aerospace and rail transportation protection in China.

Key words:

three , dimensional braided composites, three , dimensional angle , interlock composites, high , speed impact, progressive damage, structural effect, strain , rate effect

摘要： 为了探究三维纺织结构复合材料高速冲击下应变率效应和结构效应，制备了碳纤维增强三维编织和三维角联锁复合材料，采用霍普金森压杆(SHPB)系统和高速摄影系统记录了三维编织和三维角联锁复合材料在高速冲击过程中应力应变曲线和渐进损伤过程。结果表明：编织和角联锁复合材料在高速冲击下都具有一定的应变率效应，并且都呈现剪切损伤，但编织复合材料呈现明显延性损伤而角联锁复合材料呈现明显脆性损伤。由于编织复合材料内部纤维束交织紧密，损伤后仍能承受一定载荷并且结构也能保持完整性，因此相较于三维角联锁复合材料，三维编织复合材料具有更好的抗冲击性能。

关键词: 三维纺织结构复合材料, 高速冲击, 结构效应, 应变率效应