Geometry- and velocity-constrained cohesive zones and mixed-mode fracture/adhesion energy of interfaces with periodic cohesive interactions
Geometry- and velocity-constrained cohesive zones and mixed-mode fracture/adhesion energy of interfaces with periodic cohesive interactions
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DOI：
10.1098/rspa.2008.0373
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发表时间：
2009-04-08
影响因子：
3.5
通讯作者：
Gao, Huajian
中科院分区：
文献类型：
--
作者：
Chen, Bin;Wu, Peidong;Gao, Huajian
结果表明，具有周期性变化的粘结相互作用的界面的复合型断裂/粘结能一般取决于界面裂纹尖端附近粘聚区的大小：如果粘聚区的大小远远大于粘结相互作用的周期，则等于界面的平均粘结能，反之则成为局部粘结能的峰值。同样有趣的是，裂纹的几何形状和速度会强烈影响粘聚区的大小。作为几何约束粘聚区的一个例子，我们考虑了薄膜在衬底上的剥离，结果表明，908剥离以下的粘聚区大小与薄膜的弯曲刚度有关，而08剥离尺度下的粘聚区大小与薄膜的拉伸刚度有关。作为速度约束粘聚区的一个例子，我们考虑了沿着连接两个弹性介质的弱分子键的界面层的裂纹扩展，并表明在可行的裂纹速度范围内，粘聚区的大小可以改变一个数量级。这些结果提出了在工程和生物系统中控制界面断裂/粘结强度的可能策略。
We show that the mixed-mode fracture/adhesion energy of an interface with periodically varying cohesive interactions generally depends on the size of the cohesive zone near the tip of a crack along the interface: it is equal to the average cohesive energy of the interface, if the cohesive zone size is much larger than the period of cohesive interaction but becomes the peak value of the local cohesive energy when the opposite is true. It is also interesting that the cohesive zone size can be strongly influenced by the geometry and velocity of the crack. As an example of geometry-constrained cohesive zone, we consider peeling of a thin film on substrate and show that the cohesive zone size under 908 peeling scales with the bending stiffness of the film, while that under 08 peeling scales with the tension stiffness of the film. As an example of a velocity-constrained cohesive zone, we consider crack propagation along an interfacial layer of weak molecular bonds joining two elastic media and show that the cohesive zone size can be altered by an order of magnitude over feasible regimes of crack velocity. These results suggest possible strategies to control fracture/adhesion strength of interfaces in both engineering and biological systems.