【摘要】 采用平面应变的有限元模型数值模拟了热弹机制下线型脉冲激光辐照金属铝板表面激发高频声表面波,及声表面波经过表面矩形凹痕时发生反射的过程.计算结果表明:声表面波中的瑞利波经过表面凹痕时发生明显的反射,并产生两个相继出现且具有相同的传播速度的反射表面波成分;随着凹痕深度的增加,两个反射瑞利脉冲出现的时间间隔将增大;数值计算从理论的角度有力地证实了前一反射瑞利波产生于凹痕的顶端,而后者源于其底部的论断,从而为定量检测金属表面缺陷的深度提供了理论依据.更多还原

【Abstract】 Plane strain finite element method is employed in this paper to simulate the generation of surface acoustic wave by the line focused pulsed laser irradiation on the aluminum plate and the interactive process of the Rayleigh pulse generated by the laser and the surface notch.The results demonstrate that the obvious reflected Rayleigh waves have two components which propagate on the top surface with the same velocity,and that the time interval of the two waves becomes larger with the depth of surface notch increasing.The numerical simulation lends support to the judgment that the two components are generated at the top and bottom of the surface notch respectively.更多还原