Investigation of bulk material property changes and fatigue strength determination of relaxor-PT piezoelectric materials

固溶体弛豫PT压电单晶自20世纪90年代首次成功生长以来，由于其机电耦合接近理论最大值，且压电电压-应变系数远高于传统PZT陶瓷而引起了人们的极大兴趣。虽然大量的研究工作集中在几种弛豫PT材料的不同成分和晶体取向的块体特性值上，但缺乏对这些特性在不同边界条件和输入下如何变化的系统研究，以及疲劳数据。拟议的研究项目有两个主要目标。首先，用逆方法研究了弛豫PT单晶在不同边界条件和循环加载下的材料性质。第二个目标是使用实验数据和标称应力状态确定疲劳强力值。这两个结果，即改变在使用状态下的材料属性值和材料强度特性，将有助于设计者设计具有更高性能的更持久的压电器件。

Solid solution relaxor-PT piezoelectric single crystals have generated considerable interest since first being successfully grown in the 1990s due to electromechanical coupling close to the theoretical maximum and piezoelectric voltage-strain coefficients much higher than traditional PZT ceramics. While significant research effort has focused on these bulk property values for different compositions and crystal orientations of several relaxor-PT materials, there has been a lack of systematic investigation of how these properties change under different boundary conditions and inputs, as well as fatigue data. The proposed research project has two main goals. The first is to investigate the material property values for relaxor-PT single crystals under various boundary conditions and cyclic loading using the inverse method. The second goal is to determine fatigue strength values using experimental data and nominal stress state determinations. The two outcomes, namely changing material property values under service and material strength characteristics, will aid designers in designing longer lasting piezoelectric devices with improved performance.