覆盖层与基底极化方向相反时压电层状半空间中的B-G波

THE B-G WAVE IN THE PIEZOELECTRIC LAYERED HALF-SPACE FOR THE LAYER AND THE SUBSTRATE IN OPPOSITE POLARIZATION

对于覆盖层与基底介质极化方向相反的压电层状半空间 ,在自由表面电学开路和短路两种情况下 ,分别用解析的方法得到了Bleustein Gulyaev波传播的相速度方程或相速度的表达式 ;以工程技术中应用的压电材料为例考察了波速随覆盖层厚度h的变化规律 .为了分析表面金属薄膜对波的传播速度的影响 ,计算了机电耦合系数k2 与h的关系 ,结果表明 :层状结构B G波传播时具有很小的穿透深度 ,同时在h取适当值时依然可使k2

For the piezoelectric layered half space with the layer and the substrate in opposite polarization, the expressions for the phase velocity equations of the Bleustein Gulyaev wave are obtained by the analytical technique. Two kinds of electric boundary conditions at free surface are considered. The variation patterns of the wave propagation velocity along with the thickness of the layer are studied for the piezoelectric material which can be utilized in engineering technology. The following fact is found by numerical examples that the penetration depth of the B G wave is in the same order as the wavelength for layered structures. In order to study the influence of the metal film at surface on the wave propagation velocity, the relationship between the electromechanical coupling coefficient k 2 and the thickness of the layer h is computed, the numerical results indicate that for appropriate thickness of the layer, k 2 can still maintain quite high value.