基于电介质材料逆挠曲电效应的作动方法关键技术研究

Flexoelectricity is a kind of electromechanical coupling phenomenon, which exists in various kinds of dielectric materials. Converse flexoelectricity describes the mechanical stain induced by the electric field gradient. It should be possible to develop a new precise driving method and actuator with converse flexoelectricity. However, the research of converse flexoelectricity has been developing slowly owing to driving structure which is difficult to design and small driving displacement which is difficult to measure. This research intends to study the key technology of the driving method based on converse flexoelectricity in dielectric materials. In this research, it is proposed to compare the flexoelectric coefficients and converse flexoelectric coefficients, and obtain the relationship between the converse flexoelectric effect and the electrical parameters. A method to enhance the converse flexoelectric effect will be proposed. The influence of structural dimensions on converse flexoelectricity is required to be study, in order to obtain the relationship among structural dimension, electric field gradient and driving displacement. The displacement output structures based on converse flexoelectric effect are needed to be designed. The methods of displacement amplification and the measurement method of small displacement are required to develop. Then, the experiment method of converse flexoelectric effect will be improved. This research will acquire the converse flexoelectric effect at different structural dimensions and structure shape. It will provide the experimental methods of converse flexoelectric effect and technical support for the actuator of converse flexoelectric effect. This project will lay the foundation for the driving component of converse flexoelectricity.

挠曲电效应是一种广泛存在于各类电介质材料中的力-电耦合现象，其中由电场梯度导致结构应变的现象为逆挠曲电效应。逆挠曲电效应作为极高精度作动的一种新方法，可发展出新型作动器件，以实现精密位移输出。但由于其位移输出结构可设计性差、作动位移测量困难等问题，使得逆挠曲电效应相关研究进展缓慢。因此，本项目针对电介质材料逆挠曲电效应的作动方法关键技术展开研究，通过对比电介质材料的正、逆挠曲电系数，获取逆挠曲电效应与电学参数之间的关系，提出增强逆挠曲电效应的方法；通过研究结构尺度对逆挠曲电效应的影响规律，获得结构尺度、电场梯度与作动位移的关系；设计逆挠曲电效应位移输出结构形式，优化位移放大方法，研制极微小位移测量方案，发展逆挠曲电效应实验方法。本研究将获得不同结构形式和结构尺度下的逆挠曲电效应，完善逆挠曲电效应的实验方法，发展基于逆挠曲电效应的作动关键技术，为新型高精度作动器件的研制奠定基础。

基于力电耦合效应的智能材料在高端装备精密制造、大型结构健康监测、生物医学系统和人机交互界面等领域有着极为广泛的应用。其中，挠曲电效应指的是电介质材料中因应变梯度诱导产生的电极化现象（正挠曲电效应），由电场梯度产生的材料变形则是逆挠曲电效应。相对比其它的力电耦合效应，挠曲电效应与应变梯度/电场梯度的直接相关性使其在结构设计、力学调控等方面存在独特的优势。本课题项目名称为基于电介质材料逆挠曲电效应的作动方法关键技术研究，开展了挠曲电效应实验系统部件的研制工作，提出了一种不依赖摩擦力的断电位移保持作动器；进行了挠曲电效应优化实验方法研究，提出了等应变梯度结构和新型实验方法；完善了挠曲电效应解耦实验研究，获得了本征的挠曲电系数分量；提出并验证了多种增强方法，包括调控交联密度、弹性模量梯度、预应变梯度等方式；开展了逆挠曲电效应及作动方法研究，完善了实验测量系统，研制了逆挠曲电作动结构，利用增强方法使得逆挠曲电效应输出提升了1~2个数量级。本研究为挠曲电效应应用研究奠定了基础。