中文摘要：

基于金属材料近表面层弹性性质（杨氏模量）的连续变化，建立了一种激光在基底上的梯度材料中激发声表面波的理论模型，并用有限元方法模拟了脉冲激光作用于材料上表面激发出的超声波及其传播过程．讨论了表面层厚度的变化以及表面层弹性性质的变化对热弹条件下产生的声表面波波形特征的影响，并分别计算了两种情况下的声表面波的相速度色散，得到了两种情况下声表面波的变化规律．

英文摘要：

Taking account of the continuous changes of the near-surface elastic property,a model of multiple gradient layers on the substrate is estabilished. An optimized finite element is developed to simulate the laser thermo-elastic generation and propagation of surface acoustic waves in the system. The effection of the different near-surface depth and elastic property to surface acoustic wave is studied. Furthermore, the regular phase velocity is attained and analyzed.