纤维拔出时界面分离能释放率的应力函数分析

Analysis of energy release rate for interfacial debonding in fiber pull-out by using stress functions

当引入应力平衡方程、边界条件和连续性条件时,提出了一个描述纤维拔出过程中、分离界面伴随摩擦时的弹性应力传递理论模型。根据最小势能原理,获得了纤维和基体中所有应力的求解和考察界面断裂特性的分离能释放率G的表达式,且当引入一个界面分离准则G≥iΓ时,提供了一个确定临界分离长度的方法。对纤维增强复合材料SiC/Ti-6Al-4V进行了数值计算,且和shear-lag(剪滞)理论结果作比较。

By introducing stress equilibrium equations, boundary-and continuity-conditions, a theoretical model on the elastic stress transfer with friction at the debonded interface in fiber pull-out was established. Based on the minimum complementary energy principle, all stress solutions in the fiber and matrix, an expression for the energy release rate G which explores the interfaeial fracture properties were obtained. When an interracial debonding criterion G≥Гi was introduced, a method for determining the critical debond length was provided. Numerical calculations were conducted for the fiber-reinforced composite SiC/Ti-6Al-4V and the results were compared with those obtained by using the shear-lag theories.