Damage and fracture model for eutectic composite ceramics  

作　　者：Jinfeng Yu Xinhua Ni Xiequan Liu Yunwei Fu Zhihong Du 

机构地区：[1]Department of Vehicle and Electric Engineering,Army Engineering University,Shijiazhuang 050003,China [2]Army Infantry College,Nanchang 330000,China [3]Xichang Satellite Launch Center,Xichang 615000,China

出　　处：《Acta Mechanica Sinica》2019年第1期190-200,I0006,共12页力学学报（英文版）

基　　金：the National Natural Science Foundation of China(Grant 11272355).

摘　　要：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.

关 键 词：MICROCELL Interaction direct DERIVATIVE ESTIMATE DEFECT stability Damage LOCALIZATION BAND 

分 类 号：O3[理学—力学]