Liu Kun, Feng Ying, Kang Bao, Song Jie, Li Zhongxin, Wu Zhilin, Zhang Wei
School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
School of Mechanical Engineering, Nanjing Institute of Technology, Nanjing 211112, China.
Polymers (Basel). 2025 Jul 30;17(15):2097. doi: 10.3390/polym17152097.
Aramid fibre has become a critical material for individual soft body armour due to its lightweight nature and exceptional impact resistance. To investigate its energy absorption mechanism, quasi-static and dynamic tensile experiments were conducted on Kevlar 29 plain-woven fabric using a universal material testing machine and a Split Hopkinson Tensile Bar (SHTB) apparatus. Tensile mechanical responses were obtained under various strain rates. Fracture morphology was characterised using scanning electron microscopy (SEM) and ultra-depth three-dimensional microscopy, followed by an analysis of microstructural damage patterns. Considering the strain rate effect, a viscoelastic constitutive model was developed. The results indicate that the tensile mechanical properties of Kevlar 29 plain-woven fabric are strain-rate dependent. Tensile strength, elastic modulus, and toughness increase with strain rate, whereas fracture strain decreases. Under quasi-static loading, the fracture surface exhibits plastic flow, with slight axial splitting and tapered fibre ends, indicating ductile failure. In contrast, dynamic loading leads to pronounced axial splitting with reduced split depth, simultaneous rupture of fibre skin and core layers, and fibrillation phenomena, suggesting brittle fracture characteristics. The modified three-element viscoelastic constitutive model effectively captures the strain-rate effect and accurately describes the tensile behaviour of the plain-woven fabric across different strain rates. These findings provide valuable data support for research on ballistic mechanisms and the performance optimisation of protective materials.
由于其轻质特性和出色的抗冲击性，芳纶纤维已成为单兵软体防弹衣的关键材料。为研究其能量吸收机制，使用万能材料试验机和分离式霍普金森拉伸杆（SHTB）装置对凯夫拉29平纹织物进行了准静态和动态拉伸试验。在不同应变率下获得了拉伸力学响应。使用扫描电子显微镜（SEM）和超景深三维显微镜对断裂形态进行了表征，随后分析了微观结构损伤模式。考虑应变率效应，建立了粘弹性本构模型。结果表明，凯夫拉29平纹织物的拉伸力学性能与应变率有关。拉伸强度、弹性模量和韧性随应变率增加而增加，而断裂应变减小。在准静态加载下，断口呈现塑性流动，伴有轻微轴向劈裂和纤维端部变细，表明为韧性断裂。相比之下，动态加载导致明显的轴向劈裂，劈裂深度减小，纤维皮层和芯层同时断裂，以及原纤化现象，表明具有脆性断裂特征。改进的三元粘弹性本构模型有效地捕捉了应变率效应，并准确描述了平纹织物在不同应变率下的拉伸行为。这些发现为防弹机制研究和防护材料性能优化提供了有价值的数据支持。
