Complete interfacial performances of sisal fiber (a typical plant fiber) reinforced composites (SFRCs) during the single fiber pull-out experiments were investigated experimentally with numerical simulation in the present study. The single SFRCs were found to present three-interface failure. The failure behaviors of the three interfaces were characterized by in-situ acoustic emission technique and identified as interfacial failure between technical fiber and matrix, that between elementary fibers and that between micro-fibrils of cell walls using microscope observation. Statistical analysis was employed to evaluate pull-out probability of technical fiber, elementary fibers and micro-fibrils. The embedded fiber length was concluded to dominate the failure modes of SFRCs. To further gain insight in the complete failure processes and mechanisms of the multi-layer SFRCs, a triple-interface finite element model was developed based on the cohesive zone law. Quantitative comparisons of applied stress between numerical predictions and experimental results surmised that the triple-interface model could accurately describe the multi-stage pull-out behaviors of the single SFRCs.

本文通过数值模拟实验研究了剑麻纤维（一种典型的植物纤维）增强复合材料（SFRCs）在单纤维拔出实验中的完整界面性能。发现单个SFRC存在三接口故障。通过原位声发射技术表征了这三个界面的失效行为，并通过显微镜观察将其鉴定为工业纤维与基质，基本纤维之间以及细胞壁微纤维之间的界面失效。统计分析用于评估工业纤维，基本纤维和微原纤维的拔出概率。结论是，埋入式光纤的长度决定了SFRC的失效模式。为了进一步了解多层SFRC的完整失效过程和机理，基于内聚区定律建立了三界面有限元模型。数值预测与实验结果之间施加的应力的定量比较推测，三界面模型可以准确地描述单个SFRC的多阶段拉拔行为。