折线型裂纹对SH波的动力响应

利用Fourier积分变换方法，得出了无限平面中用裂纹位错密度函数表示的单裂纹散射场．根据无穷积分的性质，把单裂纹的散射场分解为奇异部分和有界部分．利用单裂纹的散射场建立了折线裂纹在SH波作用下的Cauchy型奇异积分方程．根据折线裂纹散射场和所得的积分方程讨论了裂纹在折点处的奇性应力及折点处的奇性应力指数．利用所得的奇性应力定义了折点处的应力强度因子．对所得Cauchy型奇积分方程的数值求解，可得裂纹端点和折点处的动应力强度因子。

DYNAMIC RESPONSE OF A BROKEN CRACK TO SH WAVES

The scattered field for a single crack expressed by the dislocation density function of the crack is derived based on the Fourier integral transformation method. The scattered field is separated into a singular part and regular part. By using the obtained scattered field of the single crack, Cauchy type singular integral equations for the broken crack are established. The singular stress and singular stress order at the broken point are analyzed on the basis of the scattered fields as well as the integral equations of the broken crack. The dynamic stress intensity factor (DSIF) at the broken is defined according to the obtained singular stress and singular stress order. Numerical solution of the Cauchy type singular integral equations yields the dynamic stress intensity factors for the crack tips and the broken point.