纳米纤维素对CFRP界面及损伤演化行为的影响

Effects of cellulose nanofibers on CFRP interface and damage evolution behavior

纳米纤维素作为一种低成本的可再生资源,在复合材料的增强改性中显示出独特的优势。本文使用纳米纤维素对碳纤维复合材料进行辅助增强,在弯曲加载下开展声发射监测实验。基于k-means方法确定不同损伤模式的特征频率范围和累积声发射能量,并采用扫描电镜对增强后复合材料的界面强度进行表征。结果表明:纳米纤维素增强后复合材料的损伤起始得到延缓,损伤演化过程中出现较少的声发射信号;且断裂时声发射信号的能量显著下降,基体开裂和纤维/基体脱黏的累积声发射能量分别减少了78.1%和87.6%。扫描电镜结果表明:纳米纤维素提高了纤维/基体界面的结合强度,改善了复合材料的界面性能,从而提高了其抗弯强度。

As a low-cost renewable resource,cellulose nanofibers(CNF)have shown unique advantages in the reinforcement and modification of composite materials.In this paper,cellulose nanofibers were used to reinforce carbon fiber composites.Bending test was carried out,and acoustic emission technology was used for damage assessment.Based on k-means method,the characteristic frequency range and cumulative acoustic emission energy of different damage modes were determined,and the interface strength of reinforced composites was characterized by scanning electron microscope.Results show that the damage initiation of cellulose nanofibers reinforced composites was delayed,and less acoustic emission signals appear in damage evolution.The energy of acoustic emission signals decrease during damage,and the cumulative acoustic emission energy of matrix cracking and fiber/matrix debonding decrease by 78.1%and 87.6%,respectively.Scanning electron microscope results show that cellulose nanofibers improve the interfacial properties of fiber/matrix,consequently improving the bending strength.