中文摘要：

为了研究冲击载荷下小范围损伤时材料的裂纹问题，建立了无限长条含损伤材料的反平面有限长裂纹的力学模型．从宏观唯象角度，采用Lemaitre在应变等效假设基础上建立的损伤本构方程，通过积分变换-对偶积分方程方法，获得了裂纹尖端动态应力场．动态应力强度因子的计算结果显示，在小范围损伤的情况下，随着损伤的增加，动态应力强度因子的幅值降低，反映了小范围损伤时损伤对裂纹扩展的屏蔽作用．

英文摘要：

The anti-plane mechanical model of infinite length strip in a finite length crack was established for studying the crack-tip str materials with damage embedded ess field under small-scale damage. From the macro-point of view, the dynamic stress field around mpaet loading and the crack-tip was investigated, and the Lemaitre＇s damage constitutive equation based on the hypothesis of equivalent strain is employed. A dual integral equation was deduced by both Fourier and Laplace integral transforms methods and corresponding solution was obtained using a numerical scheme. From the numerical results of a typical example, it can be seen that the dynamic stress intensity factor decreases with the damage factor increasing, showing the shielding effect of the damage to crack propagation under small-scale damage.