Su Yaxuan, Zhou Zhidong
Chengyi University College, Jimei University, Xiamen 361021, China.
Fujian Provincial Key Laboratory of Advanced Materials, College of Materials, Xiamen University, Xiamen 361005, China.
Micromachines (Basel). 2020 Dec 4;11(12):1077. doi: 10.3390/mi11121077.
Flexoelectric materials have played an increasingly vital role in nanoscale sensors, actuators, and energy harvesters due to their scaling effects. In this paper, the nonlocal effects on flexoelectric nanosensors are considered in order to investigate the coupling responses of beam structures. This nonlocal elasticity theory involves the nonlocal stress, which captures the effects of nonlocal and long-range interactions, as well as the strain gradient stress. Based on the electric Gibbs free energy, the governing equations and related boundary conditions are deduced via the generalized variational principle for flexoelectric nanobeams subjected to several typical external loads. The closed-form expressions of the deflection and induced electric potential (voltage) values of flexoelectric sensors are obtained. The numerical results show that the nonlocal effects have a considerable influence on the induced electric potential of flexoelectric sensors subjected to general transverse forces. Moreover, the induced electric potential values of flexoelectric sensors calculated by the nonlocal model may be smaller or larger than those calculated by the classical model, depending on the category of applied loads. The present research indicates that nonlocal effects should be considered in order to understand or design basic nano-electromechanical components subjected to various external loads.
由于其尺度效应，挠曲电材料在纳米级传感器、致动器和能量收集器中发挥着越来越重要的作用。本文考虑了挠曲电纳米传感器的非局部效应，以研究梁结构的耦合响应。这种非局部弹性理论涉及非局部应力，它捕捉了非局部和长程相互作用的影响，以及应变梯度应力。基于电吉布斯自由能，通过广义变分原理推导了承受几种典型外部载荷的挠曲电纳米梁的控制方程和相关边界条件。得到了挠曲电传感器挠度和感应电势（电压）值的封闭形式表达式。数值结果表明，非局部效应会对承受一般横向力的挠曲电传感器的感应电势产生相当大的影响。此外，根据所加载荷的类别，非局部模型计算得到的挠曲电传感器的感应电势值可能小于或大于经典模型计算得到的值。本研究表明，为了理解或设计承受各种外部载荷的基本纳米机电组件，应考虑非局部效应。
