基于粘结界面模型的三维裂纹扩展研究

根据界面断裂的特点,将粘结界面模型应用于有限元,采用非线性显式动力学算法,编写粘结-体积单元计算程序.其中体积和粘结单元分别采用四面体和三棱柱单元;粘结单元本构关系选择双线性内聚力-位移曲线,避免了界面完全断裂后发生穿透;以界面相对位移的形式定义线性损伤准则;以Benzeggagh-Kenane模式的扩展准则确定界面失效位移;以Turon模式的初始损伤准则确定界面启裂位移.该程序能够实现混合加载模式下材料界面断裂问题的三维数值模拟.用所编写的程序(CVFEM)分别对Ⅰ,Ⅱ,Ⅲ型裂纹扩展问题进行数值模拟,并且与Abaqus6.7计算结果进行对比.

3D Crack Propagation in Cohesive Zone Models

A cohesive zone model is employed in finite element formulation using nonlinear explicit dynamic algorithm.A 4-node tetrahedron element and a 6-node triangular prism element are chosen as volumetric and cohesive stress/displacement element,respectively.A bilinear constitutive equation is used to describe cohesive tractions and displacement jumps.Interfacial penetration of adjacent layers after complete rupture is avoided.A damage criterion is formulated in displacement jump space.The final displacement jump is calculated with Benzeggagh-Kenane's propagation criterion.The onset displacement jump is calculated with Turon's initial damage surface criterion.The code(CVFEM) can simulate material interface delamination under mixed-mode ratio loading in 3D.Three examples are shown.Numerical predictions are compared with those obtained by Abaqus 6.7.