表面效应对偏场下介电高弹体表面波传播的影响

Surface Effect on Propagation of Surface Waves in a Dielectric Elastomer Half Space Subject to Biasing Fields

采用表面薄层模型考察偏场下介电高弹体的表面效应,针对不同边界情形,建立一阶等效边界条件.基于有限变形电弹性体的线性增量理论,利用Stroh公式和Ting方法,给出等效边界条件的严格推导过程.进一步利用Stroh公式,获得了偏场下具有表面效应的介电高弹体中表面波的频散方程.以可压缩Neo-Hookean介电高弹体为例,分析了表面效应对预变形和电学偏场作用下的介电高弹体表面波传播特性的影响.结果表明,通过施加适当的偏场,可以调控和优化纳米声表器件的性能.

The thin surface layer model was used to establish the 1st-order equivalent boundary conditions to account for the surface effect of dielectric elastomers. Based on the linear incremental theory of infinitesimal motions superimposed on the finite deformation of an electroelastic body,the equivalent boundary conditions were rigorously derived with the Stroh formalism and the Ting method. The Stroh formalism was further used to deduce the governing equations for surface waves involving the surface effect. For compressible Neo-Hookean dielectric elastomers,the dispersion equations for the Love waves and generalized Rayleigh waves were derived and investigated numerically. It is found that the two types of waves are decoupled from each other,as in the classical cases. Different from the classical Rayleigh waves,the generalized Rayleigh waves with surface effect are size-dependent and uniqueness of the Rayleigh wave no longer exists. Numerical results indicate that it is possible to regulate and optimize the surface acoustic wave devices through application of appropriate biasing fields.