金刚石压砧加载下激光超声的有限元模拟  

Numerical Simulation of Laser Induced Ultrasonic in a Diamond Anvil Cell by Finite Element Method

作　　者：冯文[1] 杨德兴[1] 廖威[1] 郭钰宁[1] 

机构地区：[1]西北工业大学理学院陕西省光信息技术重点实验室,教育部空间应用物理与化学重点实验室,陕西西安710072

出　　处：《中国激光》2011年第8期89-94,共6页Chinese Journal of Lasers

摘　　要：采用有限元方法(FEM)建立了金刚石压砧(DAC)加载下脉冲激光激发超声波的数值分析模型。数值模拟了高压下样品中的瞬态温度场和超声位移场,得到了激光垂直照射下入射点异侧不同位置处的超声波波形,分析了超声位移场随时间变化的特征。结果表明,在DAC加载下,热弹作用产生的超声波具有明显的指向性,其纵波能量主要集中于激光入射方向附近,而横波的能量集中于偏离激光入射点30°～55°的倾角之间。上述特征与自由面热弹作用结果差异很大,而与自由面烧蚀作用结果相似。A numerical simulation model for a pulsed laser induced ultrasonic in a diamond anvil cell （DAC） is established by using finite element method （FEM）. The transient temperature field and ultrasonic displacement field in sample under high pressure are simulated. Ultrasonic waveforms at different positions in the rear face of sample under the irradiation of a vertically incident laser pulse are obtained, and the characteristics of ultrasonic displacement field changing with time are analyzed. The numerical results show that, ultrasonic wave generated in thermoelastic effect has obvious directionality in a DAC. The energy of longitudinal wave is concentrated near the laser incident direction, and the energy of shear wave is concentrated between 30° and 55° that deflects from the laser incident point. The characteristics are different from the results of free surface in thermoelastic effect, but they are similar to the results of free surface in ablation effect.

关 键 词：激光技术 激光超声 位移场 金刚石压砧 有限元方法 

分 类 号：TN249[电子电信—物理电子学]