WAVE PROPAGATION IN PIEZOELECTRIC LAYERED STRUCTURE WITH FLEXOELECTRIC EFFECT TAKEN INTO CONSIDERATION
作者单位：Department of applied mechanics University of Science and Technology Beijing Department of applied mathmatics Qiqihar University
会议名称：《2016年全国压电和声波理论及器件应用研讨会》
会议日期：2016年
学科分类：080801[工学-电机与电器] 0808[工学-电气工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学]
基 金：supported by Fundamental Research Funds for the Central Universities (FRF-BR-15-026A) National Natural Science Foundation of China (No. 10972029)
关 键 词：Flexoelectric effect Dipolar traction Strain gradient Reflection and transmission Energy flux ratio
摘 要：Background, Motivation and Objective In the classical piezoelectric elastic theory, the stress at a piezoelectric material point is assumed to be dependent upon the strain and electric field at same piezoelectric material point, and no characteristic length is included in the constitutive relations. Therefore, the classical piezoelectric elastic theory cannot describe the mechanical and electrical behave of piezoelectric material at the micro or nano scale and size effects. The find of the flexoelectric effects in piezoelectric solids and the potential applications at nanoscale electromechanical system make the investigation of acoustic wave propagation in the piezoelectric solid with the flexoelectric effects taken into consideration necessary. The influences of the flexoelectric effects on the wave propagation mode and the dispersive relations of these waves are therefore interesting. Statement of Contribution/Methods The reflection and transmission phenomenon of acoustic propagation at a piezoelectric half-space and through layered structure are considered. The piezoelectric solids are modeled by the generalized elastic theory with the strain gradient terms included in the constitutive relations to reflect the flexoelectric effects. Due to the flexoelectric effects, there are five kinds of wave propagation modes appeared instead of three propagation modes in the classic piezoelectric solids. Not only that, the traditional surface tractions should be modified as the monopolar surface tractions and the dipolar surface tractions. Accordingly, the traditional surface/interface conditions are replaced by the new surface/interface conditions when the flexoelectric effects are taken into consideration. Results Two boundary conditions(traction-free and electrically shorted/charge-free) and interface conditions with mechanically and dielectrically perfect and imperfect are considered in the present work. The amplitude ratios and energy flux ratios of the reflection waves