激光热弹激励流-固泄漏Lamb波的有限元模拟

根据变分原理，得到热弹体运动方程和热传导方程相对应的有限元方程. 通 过数值积分方法求解有限元方程，得到脉冲激光线源在水/铝、空气/铝这两种流-固界面 上热弹激励的泄漏Lamb波瞬态波形. 计算结果表明，泄漏Lamb波不但存在于液-固界面， 而且存在于气-固界面；和Lamb波相反，泄漏Lamb波的S_0模态是反对称的，而A_0 模态是对称的；但由于这两种流-固界面的性质差异导致泄漏Lamb波的波形和幅度不同.

FINITE ELEMENT SIMULATION OF LEAKY LAMB WAVE AT FLUID-SOLID INTERFACES EXCITED THERMOELASTICALLY BY PULSED LASER

Based on the variation principle, the corresponding finite element equations for the thermoelstic and heat conduction equations are obtained. The finite element equations for the fluid-solid interface waves propagated along the water-aluminum, air-aluminum interfaces are solved by using the numerical method of integration, and then the transient waveforms excited thermoelastically by a pulsed laser line source are obtained. The results show that the leaky Lamb wave exists at the liquid-solid interface and also exists at air-solid interface. In reverse to the Lamb wave, the S0 mode of the leaky Lamb wave is antisymmetric, and the A0 is symmetric. Due to the difference of the two kinds of fluid-solid interfaces, the waveforms and amplitudes of the two leaky Lamb waves are different.