Wang Baolai, Tian Weidong, Wang Chao, Wang Qi
Yantai Research Institute, Harbin Engineering University, Yantai 264000, China.
Polymers (Basel). 2024 Nov 30;16(23):3380. doi: 10.3390/polym16233380.
The poor interlaminar fracture toughness is a critical limiting factor for the structural applications of aramid fiber/epoxy resin composites. This study investigates the effects of laser-induced graphene (LIG) and short Kevlar fibers on the interfacial toughness and damage detection of aramid composite materials. Mode II tests and tensile tests were conducted to evaluate mechanical properties and damage detection using the piezoresistive characteristics of LIG. The results indicate that LIG combined with short Kevlar fibers significantly enhances the interfacial toughness of the composites, achieving a 381.60% increase in initial Mode II fracture toughness. Although LIG reduced the tensile strength by 14.02%, the addition of short Kevlar fibers mitigated this effect, preserving the overall mechanical performance. Scanning electron microscopy (SEM) analysis revealed enhanced toughening mechanisms, including increased surface roughness, altered crack propagation paths, and fiber bridging. Additionally, LIG enabled real-time damage monitoring, showing a significant increase in resistance upon delamination or crack propagation and a marked increase in resistance upon the tensile fracture. This research indicates that the synergistic effects of LIG and short Kevlar fibers not only enhance the interlaminar toughness of aramid composites but also provide a novel strategy for effective damage detection in fiber-reinforced materials.
层间断裂韧性较差是芳纶纤维/环氧树脂复合材料结构应用的关键限制因素。本研究调查了激光诱导石墨烯（LIG）和短凯夫拉纤维对芳纶复合材料界面韧性和损伤检测的影响。进行了II型试验和拉伸试验，以利用LIG的压阻特性评估力学性能和损伤检测。结果表明，LIG与短凯夫拉纤维相结合显著提高了复合材料的界面韧性，初始II型断裂韧性提高了381.60%。尽管LIG使拉伸强度降低了14.02%，但短凯夫拉纤维的添加减轻了这种影响，保持了整体力学性能。扫描电子显微镜（SEM）分析揭示了增强的增韧机制，包括表面粗糙度增加、裂纹扩展路径改变和纤维桥接。此外，LIG能够进行实时损伤监测，在分层或裂纹扩展时电阻显著增加，在拉伸断裂时电阻明显增加。本研究表明，LIG和短凯夫拉纤维的协同效应不仅提高了芳纶复合材料的层间韧性，还为纤维增强材料的有效损伤检测提供了一种新策略。
