两侧有固体层负载时板中Lamb波的传播

本文研究了薄板二面有固体导负载时板中Ｌａｍｂ波的传播，从弹性波理论出发并结合应的边界条件，导出板中Ｌａｍｂ波的色散方程，数值计算表示，不管作为自由状态时板中Ｌａｍｂ波相速（板厚取定时）是大于或小于外层固体的声表面波波速，板中对称及反对称模式的Ｌａｍｂ波相速都随着外层固体层厚度增加而变化并且渐近于外层固体的声表面波波速，数值计算又表明，对很薄的板，板中对称及反对称模式的相速均随负载板的厚度呈线性变化

The propagation of Lamb waves in a plate bordered by layers on both sides

This paper deals with the effect of solid layer loading on the two sides on the propagation of Lamb waves in a plate of finite thickness. Based on the theory of elastic wave and the boundary conditions, the dispersion equations of Lamb waves in such a plate are studied theoretically. Numerical solutions of the dispersion equations show than no matter the velocities of S0 and A0 mode Lamb waves of the palte of free boundary are greater or less than the velocity of Rayleigh surface wave Cs of the outer layers, the velocities of both the symmetric and antisymmetric Lamb waves asymptotically approach Cs when the thickness of the solid layers increases. Numerical computations also show that when the plate is very thin, both the velocities of S0 and A0 mode change approximately linearly with the solid loading layer thickness. Both these two modes my be used for a sensor.