各向异性编织CMC弯曲断裂失效模型

通过对缺口弯曲断裂试验的研究发现，编织CMC存在两种断裂失效模式：界面主导的和纤维束主导的失效模式．针对这两种模式建立了界面失效模型和纤维束断裂失效模型．界面失效模型用半经验方法处理弱界面和大编织角度的断裂强度问题；纤维束断裂失效模型采用解析方法处理较强界面和小角度的断裂强度问题，为含有缺口试件的弯曲强度预报打下了初步的理论基础．

A FAILURE MODEL OF 3-D BRAIDED CMC'S FLEXTURE FRACTURE

Fracture strength of 3D braided CMC with notch is influenced by numerous factors. By the facture test of bending specimen with notch, it is found that there are two kinds of failure modes of 3D braided CMC: the interface dominating failure mode and the bundle fracture dominating one. The interface failure model and bundle fracture model are established. The first one is used to deal with fracture strength of 3D braided CMC with weak interface and large braided angle by a semi-experimential method and the second one with stronger interface and little braided angle by a analytic method. The models are useful in solving problems of fracture strength of 3D braided CMC with notch under bending loads.