The influence of crack trapping on the toughness of fiber reinforced composites
The influence of crack trapping on the toughness of fiber reinforced composites
复制标题
裂纹捕获对纤维增强复合材料韧性的影响
DOI：
10.1016/s0022-5096(98)00059-3
复制
发表时间：
1998
影响因子：
5.3
通讯作者：
M. Ortiz
中科院分区：
文献类型：
--
作者：
Guanshui Xu;A. Bower;M. Ortiz
裂纹桥联是脆性纤维/脆性基体复合材料的主要增韧机制。此外，纤维可以具有第二个有益效果：它们倾向于捕获通过固体传播的裂纹，并且可以使它们停止。裂纹捕获效果随纤维与基体界面断裂韧性的增加而增加。相反，如果纤维和基体之间的界面具有低断裂韧性，则裂纹桥接倾向于更有效。本文研究了脆性纤维/脆性基体复合材料中裂纹捕获和桥接的竞争效应。数值方法是用来预测在三维的路径裂纹，因为它绕过行的纤维在一个理想的脆性矩阵。利用计算结果分析了裂纹陷阱对复合材料韧性的影响。此外，一个简单的摩擦裂纹桥接模型被用来比较裂纹捕获和桥接的相对效果。结果表明，在一般情况下，桥接的影响大大超过了陷阱。然而，如果纤维具有低拉伸强度并且纤维和基质之间存在大的滑动阻力，则裂纹捕获可能是显著的：在这种情况下，通过使用纤维和基质之间的坚韧界面来实现最佳复合材料韧性。
Frictional crack bridging is the main mechanism of toughening in brittle fiber\brittle matrix composites. In addition, the fibers may have a second beneficial effect : they tend to trap cracks propagating through the solid, and may cause them to arrest. The effectiveness of crack trapping increases with the fracture toughness of the interface between fibers and matrix. In contrast, crack bridging tends to be more effective if the interface between fibers and matrix has a low fracture toughness. In this paper, we study the competing effects of crack trapping and bridging in a brittle fiber\brittle matrix composite. A numerical method is used to predict in three dimensions the path of a crack as it bypasses rows of fibers in an ideally brittle matrix. The results are used to deduce the influence of crack trapping on the toughness of the composite. In addition, a simple model of frictional crack bridging is used to compare the relative effects of crack trapping and bridging. It is shown that, in general, the influence of bridging greatly exceeds that of trapping. However, if the fibers have a low tensile strength and there is a large resistance to sliding between fibers and matrix, crack trapping can be significant : in this case, the best composite toughness is achieved by using a tough interface between fibers and matrix.