压电功能梯度材料层反平面裂纹瞬态问题的研究

研究了压电功能梯度材料层中平行于边界的动态反平面裂纹问题．数值方法为采用积分变换和位错函数法将问题简化为Cauchy奇异积分方程，最后给出数值结果，讨论了载荷耦合参数、材料分布形式和裂纹位置等因素对断裂行为的影响．结果发现，载荷耦合参数对规一化应力强度因子的影响比对规一化电位移强度因子的影响大，而电载荷的加载方向将决定动态应力强度因子在不同阶段的行为．此外，电载荷的存在总是促进裂纹扩展，但裂纹在负的电载荷作用下比在正的电载荷作用下更易扩展．

Transient Response of Functionally Graded Piezoelectric Layer with Finite Crack under Electromechanical Impact Load

The dynamic anti\|plane problem for a functionally graded piezoelectric layer containing a crack parallel to the boundary was considered. Integral transforms and dislocation density functions were employed to reduce the problem to Cauchy singular integral equations. The numerical results show the effects of loading combination parameter, material distribution and crack configuration on the fracture behavior. It is found that the loading combination parameter has more significant influence on the normalized stress intensity factor than that on the normalized electric displacement intensity factor. The direction of applied electric load determines the behavior of dynamic stress intensity factor at different stages. In addition, the existing electric load always enhances the crack propagation. However, the crack is easier to propagate under the negative electric load than under the positive load.