基于流体固体耦合理论,采用有限元方法,建立流固界面激光产生超声波的有限元数值模型。数值模拟研究激光热弹激励流固界面超声波的激发和传播,分析了泄露瑞利波,Scholte波,侧面波(Lateral波)的传播特征,得到了全波场数值解。进而分析不同流体介质对于界面波形的影响。计算结果表明,激光在流固界面同时激发出多种模态波形,且流体的材料参数对波形有重要影响。数值模拟建立了激光参数、材料参数以及相应的波形之间的定量关系。

A numerical model based on the theory of fluid-structure interaction is developed by finite element method to simulate the laser thermo-elastic generation and propagation of interface waves at the fluid-solid interface. The propagation characteristics of leaky-Rayleigh wave,Scholte wave and lateral wave are analyzed,and the numerical solution of full wave field is obtained. Furthermore,the effect of different fluid media on the waveform of interface waves is discussed. The results show that various modes of fluid-solid interface waveform are excited simultaneously by pulsed line source,with the waveform significantly affected by the material parameters of liquid media. The numerical simulation establishes a quantitative relation between the laser parameters,the material parameters and the corresponding waveform.