三维垂直裂纹在材料界面的扩展及影响因素

 针对三维垂直裂纹扩展到双材料界面时的路径选择问题,建立了双材料三维垂直裂纹在界面扩展的计算模型,提出了三维垂直裂纹在材料界面扩展的3 种方式及判断准则;以线弹簧模型模拟两种材料间的界面胶结情况,得到了裂纹在界面处的剪切位移及剪切应力,结合虚拟裂纹扩展技术计算能量释放率沿裂纹边缘的分布情况,分析了裂纹长度、界面参数及材料弹性模量对裂纹扩展路径的影响。结果表明,随着裂纹长度的增大,界面剪切位移逐渐增大,界面容易发生剪切滑移;随着界面参数的增大,能量释放率减小,同时,剪切位移也随之急剧减小,说明界面参数的增大对阻止裂纹穿透界面及沿界面扩展具有明显作用;当裂纹在较硬材料内时,裂纹容易穿透界面进入较软材料内。

Propagation of 3D vertical crack on material interface and its influencing factors

When a 3D vertical crack propagates on the interface between bi-materials, there are three route choices. To study this problem, a crack propagation model of the 3D vertical crack on material interface is established. A linear spring layer model is used to simulate the imperfect interface and calculate the shear displacement and the shear stress along the interface. Then, the distribution of the energy release rate is calculated along the edge of the crack. The influencing factors of route choices, such as the crack length, the interface parameters and the elasticity modulus, are analyzed. It is shown that the interface shear displacement increases with the increase of the crack length, which means that the interface slips easily. The larger the interface parameters, the smaller the energy release rate and the interface shear displacement will be. In other words, the crack propagation through and along the interface might be greatly hampered if the interface parameters increase. When the crack is in the harder material, it might penetrate the interface and goes into the softer material easily.