碳纳米管膜层间增强增刚玻纤织物复合材料压缩强度的实验与数值模拟

Experiment and numerical simulation of compressive strength of interlaminar reinforced and stiffened glass fiber fabric composites with CNT films

  • 摘要: 碳纳米管膜层间增强增刚技术是改善复合材料压缩强度的有效手段,而对其压缩过程的试验研究可以直观了解碳纳米管膜对压缩性能的影响,有限元分析则有助于深入分析压缩强度的提升机制。本文制备了碳纳米管/环氧树脂复合膜(CECF)层间增强增刚玻纤织物复合材料(CECF/GFRP),研究了CECF对复合材料宏/细观损伤形貌的影响;建立了双尺度有限元与渐进损伤模型,对比了压缩过程的试验与有限元模拟应力-应变曲线,并从双尺度下分析了复合材料压缩过程中的损伤行为。结果表明,CECF减少了复合材料压缩过程中层内与层间损伤;同GFRP复合材料相比,CECF/GFRP复合材料的压缩强度试验值与有限元模拟值分别提高了14.1%与15.2%;宏观有限元分析表明,CECF的引入提高了复合材料抵抗层内纤维屈曲以及层间分层的能力;细观有限元分析进一步表明CECF缓解了经纱与纬纱交织薄弱区域的应力集中,抑制了纬纱纤维的基体压缩损伤以及经纱纤维的屈曲,同时层间界面强度的提升有效约束了层间分层损伤,两方面的协同作用显著改善了复合材料的经向压缩强度。

     

    Abstract: Interlaminar reinforcing and stiffening based on CNT films was demonstrated as an effective approach to improve the compressive strength of fabric composites. The influence of carbon nanotube(CNT) films on compressive properties could be directly comprehended through experimental research, and finite element analysis was conductive to in-depth analysis of the improvement mechanism of compressive strength. In this paper, the interlaminar reinforcing and stiffening glass fiber fabric composites with CNT/Epoxy films (CECF/GFRP) were prepared, and the effect of CECF on the macroscopic/microscopic damage morphologies of composite were studied. The finite element model of macro/meso dual-scale and progressive damage model were established, and the compressive stress-strain curves between experiment and finite element simulation were compared, then the damages of composites were analyzed from dual-scale during compression process. Results showed that the intralayer and interlayer compression damages in composite were inhibited due to the introduction of CECF. Compared with GFRP composites, the experimental and finite element simulation values of compressive strength of CECF/GFRP composites were increased by 14.1% and 15.2%, respectively. The finite element models with macro-scale showed that the ability to resist the intralayer fiber buckling and interlayer delamination was enhanced by CECF in the composite. The finite element models with meso-scale indicated that the stress concentrations of the intertwined regions of warp and weft fibers were relieved by CECF, which inhibited the matrix compression damage of the weft yarn fibers and the buckling of the warp yarn fibers. Also, the improvement of interlayer interface strength effectively restrained the interlayer delamination damage, leading to the increase in compressive strength of CECF/GFRP composite.

     

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