微纳米薄膜材料中激光皮秒超声的数值模拟  

Numerical modeling of laser-induced picosecond ultrasound in micro-nano thin films

作　　者：许伯强[1] 张子国[2] 徐晨光[1] 徐桂东[1] 杨小平[2] 

机构地区：[1]江苏大学理学院,江苏镇江212013 [2]江苏大学机械工程学院,江苏镇江212013

出　　处：《江苏大学学报（自然科学版）》2012年第1期83-87,101,共6页Journal of Jiangsu University：Natural Science Edition

基　　金：国家自然科学基金资助项目(11172114);江苏省高校自然科学研究重大项目(10KJA140006)

摘　　要：基于双温模型和热弹性耦合理论,采用有限元方法,针对Al/Si3N4和Al/Si3N4/Si两种层状薄膜材料中激励皮秒超声,建立激光飞秒超声的有限元数值模型,得到Al薄膜中电子和晶格的温度场,进而分析薄膜内部的应变和表面位移响应.对比研究了双温模型理论和傅里叶热传导理论的计算,结果表明皮秒超声研究采用双温模型求解温度场更为合适,数值分析得到应变具有幅值较小且波形展宽的结果.表面位移响应峰的形成是超声波在薄膜材料界面处发生反射引起的.Based on two temperature model（TTM） and thermalelastic theory,finite element numerical model of femtosecond laser-induced picosecond ultrasound was applied in investigating laser interaction of Al/Si3N4 and Al/Si3N4/Si multilayer thin films.The temperature fields of electron and lattice in Al film were caculated by the finite element method to analyze the surface displacement response and strain in thin films.The computational result from TTM theory was compared with that from classical fourier heat transfer theory.The comparison indicates that TTM theory is suitable for picosecond ultrasonic investigation.According to numerical analysis,the strain amplitude is small with wide waveform.The peaks of displacement response spectrum on Al surface are induced by ultrasound reflection within the interface of films.

关 键 词：薄膜 双温模型 皮秒超声 有限元 数值模拟 

分 类 号：O426.9[理学—声学]