局部温差作用下压电薄膜的变形与电场分析

Deformation and Electric Field Analysis of Piezoelectric Films under the Effect of Local Temperature Difference

基于热压电理论考虑一阶和二阶变形之间的耦合对压电薄膜内部的力学和电学行为进行分析.论文推广了传统的弹性Mindlin板模型到多物理场上,建立了具有局部温度场的压电薄膜模型,作为应用,研究了局部温度变化对压电薄膜变形和电场的调控效果.利用Navier解理论求解压电薄膜在厚度伸缩变形时的位移场和电势场.接下来进行了数值研究,结果表明:局部升温(降温)会导致加载区域内的厚度拉伸(收缩)变形,同时伴随着面内拉伸(收缩)变形和二阶剪切变形,薄膜的面内变形在上表面和下表面的温度加载区域达到最大,两处区域分别产生电势阱(电势垒)和电势垒(电势阱),这表明利用局部温度场可以实现对压电薄膜变形和电场的非接触式调控.本研究是对具有热弹性效应和热释电效应的压电薄膜结构分析理论的一个扩展,为微纳米尺度器件的结构设计提供参考.

Due to the trend of miniaturization of electronic devices,the size of many piezoelectric thin-film devices has reached the nanometer scale.The electric field and displacement field in piezoelectric thin-film devices can be controlled using the temperature field.At present,the influence of the coupling of the first-and second-order deformations on the internal mechanical and electrical behavior of piezoelectric thin films has not been considered in the two-dimensional plate theory research on thermal stress.In this paper,the traditional elastic Mindlin plate model is extended to multiple physical fields,the thermal stress and pyroelectric effect are considered,and the coupling relationship between thickness stretch deformation,in-plane extension and second-order shear deformation is taken into account.A piezoelectric film model with local temperature field is established.As an application,the effect of local temperature change on the deformation and electric field of piezoelectric thin films is studied.The displacement field and electric potential field of piezoelectric films during the thickness-stretch deformation are calculated using the theory of Navier’s solution.Then a numerical study is carried out.The results show that:local heating/cooling would lead to thickness stretch/shrinkage in the loading area;and with in-plane extension/shrink-age and second-order shear deformation,the in-plane deformation of the film can reach the maximum in the temperature loading area of the upper surface and the lower surface,and the two areas produce potential wells/barriers and potential barriers/wells,respectively.This shows that the local temperature field can be used to control the deformation and electric field of the piezoelectric film.This study is an extension of the structural analysis theory of piezoelectric thin films with thermoelastic and pyroelectric effects,and provides a reference for the structural design and optimization of micro-and nano-scale devices.