基于局部法评定TBCs/Q345涂层界面断裂行为

通过对涂层试样进行拉伸试验得到界面断裂时的临界载荷．采用ABAQUS有限元软件模拟了涂层试样的断裂行为．推导了基于统计学思想的局部法用于界面断裂的理论公式，通过编制Fortran程序求出影响界面断裂的威布尔参数．采用局部法分析了涂层界面断裂行为对试样缺陷尺寸的依赖性．发现临界威布尔应力与试样尺寸和加载形式无关，不同缺陷尺寸的试样发生界面断裂时，在相同断裂概率下其威布尔应力基本相同，并基于局部法通过预制裂纹试样的试验结果成功预测了另一种裂纹尺寸试样的断裂数据分布，说明局部法可以用来描述涂层界面的断裂行为，并用于界面完整性评定中．

Research on interfacial fracture behavior of TBCs/Q345 based on local approach

The critical load at crack propagation for the coated specimens was obtained through the tensile test, and the finite element method(FEM) was conducted to simulate the fracture behavior by ABAQUS code.Then the results from FEM were input into a self-programmed FORTRAN code, the two parameters of Weibull distribution dominating the interfacial fracture were obtained.The mathematical formula of the local approach applied to analyze the interface fracture was deduced.After that, the local approach was adopted to analyze the crack-size dependence of coating specimens for interface brittle fracture initiation.It was found that the Weibull stress for all specimens is almost identical under the same fracture probability when the interface fracture initiation occurs for different crack-size specimens.Moreover, the interface fracture behavior of one type of specimens with crack can be predicted from the test results of the other type of pre-crack specimens based on the local approach, and the predicted results have a good agreement with the test results.It showed that the local approach not only can be used to describe the interface fracture behavior, but also can be used in the integrity evaluation for interface between different materials.