Interface fracture prediction of multi-material hybrid structures by modified phase field models

When it comes to load transmission of multiple materials in hybrid structures, the interface is crucial. In this paper, the driving force in the established phase field model for predicting the interface fracture behavior is the contribution of mode-I and II fracture energy based on an approximate method. The model can be used to investigate the mixed mode failure by adding the compression strain energy along with the tension strain energy. The correctness of the model is verified experimentally, and the effectiveness is compared with other phase field models. This model investigates the effects of interfacial cohesion, internal friction angle, and fracture energy on failure behaviors. As per the findings, the increasing interfacial adhesion, mode-I fracture energy reduce the interface strength, while the internal friction angle affects it differently. However, the increase of mode-I fracture energy has no effect on compressive-shear fracture patterns of cracks, which is primarily determined by mode-II fracture energy. The interfacial fracture patterns change from normal shear to lateral fractures with the decrease of mode-II fracture energy. Furthermore, the mechanism of interface void defects on fracture behaviors of the multi-material structures has been explained.