复合材料 ENF 试件裂纹扩展理论分析简

 对复合材料端部缺口弯曲（ENF）试件裂纹扩展过程进行了理论分析，研究了界面参数变化对载荷-位移曲线的影响。首先在梁微段分析的基础上，通过双线性Cohesive本构模型模拟了界面损伤。本文模型中考虑了轴力的影响，根据界面损伤程度对模型进行了分段，并分别获得了各段通解。以裂纹长度以及黏聚区范围为变量分析了ENF试件裂纹扩展过程，求解获得了载荷-位移曲线。通过与已有理论模型结果对比，验证了本文理论分析的正确性，且本文理论考虑了弹性段后非线性的存在。分析了界面参数与黏聚区长度的关系，为界面参数的选取提供了一定的依据。

Theoretical Analysis of Crack Propagation in Composite ENF Specimens

A theoretical analysis of crack propagation in end notch flexure (ENF) specimens is carried out, and the influence of the interface parameters on its load-displacement curve is investigated. Based on the micro analysis of a beam, the interface damage is simulated using a bilinear cohesive constitutive model. In this paper the influence of the axial force is taken into account. The model is segmented according to the degree of interface damage, and a general solution of each segment of the ENF specimen is obtained. The crack length and the cohesive zone range are taken as variables to analyze the ENF specimen crack propagation process and obtain the load-displacement curve. To verify this theoretical analysis when the nonlinear phenomenon after elastic deformation is considered, some comparisons are made with the existing theoretical results. The relationship between the interface parameters and the cohesive zone length is investigated. These results provide a basis for the selection of interface parameters.