Li Ke, Jing Shuangxi, Yu Jiangong, Zhang Xiaoming, Zhang Bo
School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo 454003, China.
Materials (Basel). 2020 May 18;13(10):2320. doi: 10.3390/ma13102320.
The research on the propagation of surface waves has received considerable attention in order to improve the efficiency and natural life of the surface acoustic wave devices, but the investigation on complex Rayleigh waves in functionally graded piezoelectric material (FGPM) is quite limited. In this paper, an improved Laguerre orthogonal function technique is presented to solve the problem of the complex Rayleigh waves in an FGPM half-space, which can obtain not only the solution of purely real values but also that of purely imaginary and complex values. The three-dimensional dispersion curves are generated in complex space to explore the influence of the gradient coefficients. The displacement amplitude distributions are plotted to investigate the conversion process from complex wave mode to propagating wave mode. Finally, the curves of phase velocity to the ratio of wave loss decrements are illustrated, which offers extra convenience for finding the high phase velocity points where the complex wave loss is near zero.
为了提高表面声波器件的效率和使用寿命，表面波传播的研究受到了广泛关注，但对功能梯度压电材料（FGPM）中复瑞利波的研究却相当有限。本文提出了一种改进的拉盖尔正交函数技术来解决FGPM半空间中的复瑞利波问题，该技术不仅可以得到纯实值解，还可以得到纯虚值和复值解。在复空间中生成三维色散曲线，以探究梯度系数的影响。绘制位移振幅分布，以研究从复波模式到传播波模式的转换过程。最后，给出了相速度与波损耗减量之比的曲线，这为寻找复波损耗接近零的高相速度点提供了额外的便利。
