2021 年 87 巻 899 号 p. 21-00119
The stress intensity factors (SIFs) for an interfacial corner, which are compatible with that for a crack, can describe the singular stress field around the corner. However, due to the difference of the singular order with the angle of a corner and the combination of materials, we cannot compare the SIFs of interfacial corners to that with different singular orders. In this study, we estimated the fracture toughness (critical SIF) of jointed interfacial corners with different opening angles and different combinations of materials using the molecular statics method and cohesive zone model. The critical SIFs were normalized using those of interfacial cracks with the same combinations of materials. Regarding the relationships between the normalized critical SIF and the singular order for the numerical experiments using both the molecular statics method and cohesive zone model, the normalized SIF increased exponentially with decreasing singular order. The relationship between the singular order and the critical SIF obtained by the molecular statics or the cohesive model was almost unique regardless of the combination of materials and jointed angles. In other words, it is possible to translate the critical SIFs of a jointed interfacial corner to that of interfacial crack. However, the slopes of the relationship obtained by the molecular statics and the cohesive zone model did not correspond. This might be because only the molecular statics method considers the influence of crystal structure factors such as slip and dislocation. The interactions between atoms of the molecular statics and cohesive zone model along the interfaces are different. The relationship between the singular order and the critical SIF of actual jointed interfacial corner must be investigated experimentally in further research.
