Shaanxi Key Laboratory of Ultrasonics, Institute of Applied Acoustics, Shaanxi Normal University, Xi'an 710119, China.
Beijing Graphene Institute (BGI), Beijing 100095, China.
Ultrasonics. 2022 Mar;120:106640. doi: 10.1016/j.ultras.2021.106640. Epub 2021 Nov 20.
Ring piezoelectric transducers (rPETs) have attracted multitudinous attentions due to their widespread applications in hydro-acoustic engineering, structural health monitoring, and energy harvesting. However, cracks are inevitably occurred by the concentrated stress at the interface between metal and piezoelectric ceramics, which will seriously affect the performance and service life of the devices. Hence, a novel functionally graded ring piezoelectric transducer (FG-rPET) has been designed and an accurate analytical system is constructed mainly including a three-port electromechanical equivalent circuit model (EECM) which can acquire exact solutions in radial vibration. In addition, the proposed three-port EECM has excellent generalizability, which is also applicable to conventional rPETs. The validity of the EECM is verified by experiments and the finite element method. The vibration characteristics (resonance/anti-resonance frequencies and effective electromechanical coupling coefficient (k)) with fundamental and second modes for the FG-rPETs can be regulated via the inhomogeneity index and wall thickness. Markedly enhanced k at second modes can be obtained for the FG-rPETs with specific wall thicknesses. The proposed analytical system has important guiding significance for structure optimization design of piezoelectric devices, and the designed FG-rPET is expected to break the bottleneck of mechanical properties for the conventional rPETs.
环形压电换能器（rPET）由于在水声学工程、结构健康监测和能量收集等领域的广泛应用而引起了众多关注。然而，金属和压电陶瓷之间的界面处的集中应力不可避免地会导致裂纹的产生，这将严重影响器件的性能和使用寿命。因此，设计了一种新型的功能梯度环形压电换能器（FG-rPET），并构建了一个精确的分析系统，主要包括一个三端口机电等效电路模型（EECM），该模型可以在径向振动中获得精确解。此外，所提出的三端口 EECM 具有出色的通用性，也适用于传统的 rPET。通过实验和有限元方法验证了 EECM 的有效性。通过不均匀性指数和壁厚，可以调节 FG-rPET 的基频和二次模态的振动特性（谐振/反谐振频率和有效机电耦合系数（k））。对于具有特定壁厚的 FG-rPET，可以获得显著增强的二次模态 k。该分析系统对压电器件的结构优化设计具有重要的指导意义，所设计的 FG-rPET 有望突破传统 rPET 机械性能的瓶颈。
