Study of damage and fracture models to analyze the fracture mechanism of eutectic composite ceramics is of considerable importance because no accurate fracture models are available for these materials. Eutectic compos...Study of damage and fracture models to analyze the fracture mechanism of eutectic composite ceramics is of considerable importance because no accurate fracture models are available for these materials. Eutectic composite ceramics are composed of microcells with random direction. We present herein a model that predicts the damage and fracture of eutectic composite ceramics based on analysis of defect stability and the damage localization band. Firstly, given the microstructure of eutectic composite ceramics, a mesodomain and a microcell model are constructed. The local stress field in the mesodomain is then analyzed based on the interaction direct derivative estimate. Secondly, the stability of a defect around particles in a microcell is analyzed, and the stress intensity factor of an annular defect under the applied stress field and the residual stress field in the particle are calculated. The stress intensity factor of a defect is controlled by the residual stress when the defect extension is small. However, it is controlled by the applied stress when the defect extension is large. Finally, a model for the damage localization band at the crack tip is constructed based on the Dugdale-Barenblatt model. The residual intensity is the important factor affecting the length of the damage localization band. When the damage variables reach their largest value, the residual in ten sity and the length of the damage localization band attain their minimum value. This work provides the theoretical basis for further study of the damage mechanics of eutectic composite ceramics and guides the engineering applications of these materials.展开更多
基金the National Natural Science Foundation of China(Grant 11272355).
文摘Study of damage and fracture models to analyze the fracture mechanism of eutectic composite ceramics is of considerable importance because no accurate fracture models are available for these materials. Eutectic composite ceramics are composed of microcells with random direction. We present herein a model that predicts the damage and fracture of eutectic composite ceramics based on analysis of defect stability and the damage localization band. Firstly, given the microstructure of eutectic composite ceramics, a mesodomain and a microcell model are constructed. The local stress field in the mesodomain is then analyzed based on the interaction direct derivative estimate. Secondly, the stability of a defect around particles in a microcell is analyzed, and the stress intensity factor of an annular defect under the applied stress field and the residual stress field in the particle are calculated. The stress intensity factor of a defect is controlled by the residual stress when the defect extension is small. However, it is controlled by the applied stress when the defect extension is large. Finally, a model for the damage localization band at the crack tip is constructed based on the Dugdale-Barenblatt model. The residual intensity is the important factor affecting the length of the damage localization band. When the damage variables reach their largest value, the residual in ten sity and the length of the damage localization band attain their minimum value. This work provides the theoretical basis for further study of the damage mechanics of eutectic composite ceramics and guides the engineering applications of these materials.
基金supported by the STI2030-Major Projects(2021ZD0203100)the National Natural Science Foundation of China(31922030,32171010,31771170,31900720,and 32171009)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2023B1515040010,2021B1515020035,2019A1515011598,and 2023A1515010478)the Science and Technology Program of Guangdong(2018B030334001)the Science and Technology Program of Guangzhou(202007030012)the Programme of Introducing Talents of Discipline to Universities(B14036).
