短脉冲激光辐照的非傅里叶热力耦合效应  

Effects of NonFourier Thermal-Mechanical Coupling in Materials Irradiated by Short-Pulse Laser

作　　者：李名锐[1] 胡汉平[1] 

机构地区：[1]中国科学技术大学热科学和能源工程系,安徽合肥230026

出　　处：《中国激光》2009年第8期2004-2008,共5页Chinese Journal of Lasers

基　　金：国家自然科学基金(50476024)资助课题

摘　　要：将非傅里叶耦合热弹性方程无量纲化得到了通用的表征热力耦合效应的无量纲数λ;通过分析比较无量纲非傅里叶耦合与非耦合热弹性方程的级数解,研究了短脉冲激光辐照的非傅里叶热力耦合效应的特性。发现热力耦合不仅使光致热应力波较非耦合的波速增大,波长变长,波幅在传播过程中不断衰减,并使该应力波激发出与其速度相同的第二温度波。不论耦合与非耦合,应力波随参数ε的变化均具有饱和特性且在某一条件下呈现奇异的双峰波形。热力耦合效应的强弱主要取决于λ;另外还取决于脉冲触发后经历的时间和脉冲底宽之比,比值越大,耦合效应越强。因而对于超短脉冲激光辐照情况,在通常λ的绝对值较小(10^(-3)量级及以下)的情况下,忽略热力耦合效应也可能会导致较大误差。By dimensionless analysis and comparison between coupled and uncoupled nonFourier thermoelastic equations and their solutions, the general non-dimensional number λ characterizing effect of thermal-mechanical coupling is given, and the effects of nonFourier thermal-mechanical coupling in materials irradiated by short laser pulse are investigated. It is shown that the thermal-mechanical coupling makes the laser-induced stress wave have higher speed, longer length and dampes swing compared with the uncoupling wave, it also excite a synchronous second temperature wave. The stress wave has saturation characteristic with increasing of parameter ε, and the stress wave can bear an exceptional dual-peak waveform under special conditions, whether it is coupling or uncoupling. The intensity of thermal-mechanical coupling depends mainly on λ, and also on the ratio of elapsed time from the pulse triggering to pulse duration, the larger the ratio value is, the stronger the coupling effect is. Therefore, large error can also be caused by ignoring thermal-mechanical coupling in analysis of a medium heated by ultra-short laser pulse, even under usual conditions with smaller absolute value of λ （10^-3 and lesser order of magnitude）.

关 键 词：激光技术 短脉冲激光 无量纲级数解 非傅里叶热力耦合 应力波 

分 类 号：O347.4[理学—固体力学]