Abstract Bio-inspired composites can achieve excellent toughness while maintaining their strength through hierarchical microstructure designs combining strong and brittle reinforcements and soft yet ductile matrices. The interfaces between reinforcements and matrices transfer loads through shear deformation and deflect cracks along themselves to dissipate a considerable amount of energy. In this way, the catastrophic failure, which is common in monolithic reinforced materials due to the severe stress concentration near the defects, is deferred in hierarchical composites. Yet, recent computations and experiments suggest that strain localization arising from the unstable crack propagation along interfaces leads to the composites failure. In this study, fracture analysis is carried out on staggered composites with the brick-and-mortar structure. An analytical formula predicting the onset of strain localization emerges from the analysis and is validated by finite element analysis. Furthermore, showing good agreements with independent tensile tests on multi-layer graphene assemblies, our model demonstrates its applicability to explain the strain localization in composites consisting of interfaces that function through re-formable bonds. Characteristic length scales emerging from the analysis can be used to guide the composites design to optimize material toughness and ductility.

中文翻译：

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通过剪切滞后模型的断裂分析揭示交错复合材料中的裂纹稳定性和应变局部化

摘要 仿生复合材料通过将强而脆的增强材料与柔软而具有延展性的基体相结合的分层微观结构设计，可以在保持强度的同时获得优异的韧性。钢筋和基体之间的界面通过剪切变形传递载荷，并使裂缝沿自身偏转以耗散大量能量。这样，由于缺陷附近的严重应力集中而在整体增强材料中很常见的灾难性失效在分层复合材料中被推迟。然而，最近的计算和实验表明，由沿界面的不稳定裂纹扩展引起的应变局部化导致复合材料失效。在本研究中，对具有实体结构的交错复合材料进行了断裂分析。从分析中得出了预测应变局部化开始的分析公式，并通过有限元分析进行了验证。此外，我们的模型与多层石墨烯组件的独立拉伸测试显示出良好的一致性，证明其适用于解释复合材料中的应变局部化，复合材料由通过可重新形成的键起作用的界面组成。从分析中得出的特征长度尺度可用于指导复合材料设计以优化材料韧性和延展性。我们的模型证明了其适用于解释复合材料中的应变局部化，复合材料由通过可重新形成的键起作用的界面组成。分析中出现的特征长度尺度可用于指导复合材料设计以优化材料韧性和延展性。我们的模型证明了其适用于解释复合材料中的应变局部化，复合材料由通过可重新形成的键起作用的界面组成。分析中出现的特征长度尺度可用于指导复合材料设计以优化材料韧性和延展性。