基于纳米压痕的挠曲电系数表征方法研究

Electromechanical materials have a wide application prospect in the fields of structural health monitoring of spacecraft, remote medical treatment and brain-computer interaction technology. Electromechanical coupling property at micro/nano-scale is one of the focus researches for intelligent material and structural health monitoring. This topic is an interdisciplinary issue which involves mechanics, physics and material science. The strain gradient at micro/nano-scale can be much larger than that at macro-scale; therefore the flexoelectrocity (the coupling between strain gradient and polarization) become obvious. The piezoelectric effect bring difficulties for the characterization of the flexoelectric coefficient. In present work, by employing the nanoindentation method, the analytical characterization method for the flexoelectric coefficient will be established. The mechanism for the micro/nano-scale deformation will be studied using numerical method. The experimental characterization for the flexoelectric coefficient will be implemented. We expect to gain original achievements in the characterization method for the micro/nano-scale flexoelectric coupling property, which can provide the theoretical and method guidance for its application in fields such as aerospace and aviation.

力电耦合材料在航天器结构健康监测、天地远程医疗和脑机交互技术等方面具有广泛的应用前景，其在微纳尺度的性能表征方法是智能材料与结构领域的研究热点和难点，涉及力学、物理和材料等多学科交叉。由于微纳尺度下材料的应变梯度可以远大于宏观尺度，挠曲电效应（即应变梯度与极化强度之间的耦合效应）凸显。但由于压电效应的存在，挠曲电系数的实验表征极为困难。本项目将充分利用纳米压痕方法的优势，通过理论推导建立微纳米尺度的挠曲电系数表征方法，通过数值计算研究力电耦合材料的挠曲变形机理，并实现对微纳尺度挠曲电系数的实验表征。期望在微纳尺度挠曲电系数表征方法方面获得原创性成果，为其在航天、航空等领域的工程应用提供理论与方法指导。

压电材料在航天器结构健康监测、天地远程医疗和脑机交互技术等方面具有广泛的应用前景，其在微纳尺度的力电耦合性能是智能材料与结构健康监测领域的研究热点和难点，涉及力学、物理和材料等多学科交叉。在微纳尺度下材料的应变梯度可以远大于宏观尺度，梯度耦合效应凸显，给压电材料耦合性能的测试与表征带来困难。本项目充分利用纳米压痕方法的技术优势，通过理论推导、数值计算和实验研究，建立了微纳尺度下压电材料的挠曲电系数表征方法，揭示了压电材料在微纳米尺度的变形机理，完成了对挠曲电效应的微纳尺度实验表征。在压电材料微纳尺度力电耦合性能表征方法方面获得了原创性成果，为其在航天、航空等领域的工程应用提供了理论与方法指导。