中文摘要：

一个激光 ultrasonics 方法被用来波浪在材料的表面上旅行出现描绘繁殖性质与在 2D 的表面下的缺点。缺点引起的 ultrasonics 的线性、非线性的繁殖性质在实验被检测了。一个理论模型被建议并且过去常学习缺点引起的 ultrasonics 的线性、非线性的性质。当有限振幅 ultrasonics 与表面下的缺点在材料的表面上宣传时，数字结果显示非线性的超声的波浪将是激动的。理论分析证实非线性的波浪被鼓掌缺点的接口而不是 ultrasonics 的模式变换引起。

英文摘要：

A laser ultrasonics method is used to surface wave traveling on the surface of materials characterize the propagation properties of with sub-surface defect in 2D. Linear and nonlinear propagation properties of ultrasonics caused by the defects have been detected in experiment. A theoretical model is proposed and used to study the linear and nonlinear properties of ultrasonics caused by the defect. The numerical results indicate that the nonlinear ultrasonic wave will be excited when a finite amplitude ultrasonics propagates on the surface of materials with sub-surface defect. The theoretical analysis confirms that the nonlinear wave is caused by the ＂clapping＂ of the interface of defect instead of the mode conversions of ultrasonics.