Numerical study on the effects of hierarchical wavy interface morphology on fracture toughness

In this paper, we investigate the effects of the hierarchical wavy morphology of an interface on the apparent interfacial fracture toughness. First, the influence of two-level hierarchical sinusoidal geometry under mode-I and mode-II far-field loadings on crack propagation behavior is numerically studied by using a cohesive zone model. Second, the effects of interfacial friction on the mode-II effective fracture toughness are examined. The results show that an interface with a hierarchical sinusoidal structure has relatively higher fracture resistance ability, especially for mode-II cracks, than an interface with a flat or pure sinusoidal interface. Moreover, it is found that interfacial friction notably enhances the mode-II fracture toughness of a hierarchical sinusoidal interfacial crack. This study is helpful not only for understanding the superior mechanical properties of some biological materials, but also for optimal design of advanced composites with enhanced fracture toughness.