Abstract

Recently, non-prismatic beams have been considered as perfect substitutes to replace uniform cantilever beam structures in harvester design. This is due to their tendencies to provide uniform strain distribution, which enhances piezoelectric (PZT) charge generation when coupled with the beams. As the voltage produced by the PZT depends largely on the geometrical shape of the substrate, thus there is need for formulations to analyze the behavior of the shim prior to practical implementation. In this paper, analytical and finite element models were developed to study deflection and strain distribution of a non-prismatic beam termed, wedge edged cantilever (WEC) for patch-like harvester application. The analyses offer possibility for maximum utilization of strain location along the beam span for efficient harvester design. Vibration energy harvesting characteristics of the WEC beam with partially covered PZT material forming three configurations namely: Config1, Config2 and Config3 were studied. Both numerical and experimental results show that Confg3 with macro fiber composite (MFC) as the PZT material covering the determined optimal strain position yielded 2 to 3 times more peak output voltage than Config1 and Config2 with the MFC bonded at non-optimal positions.

摘要

最近，非棱柱形梁被认为是采伐机设计中均匀悬臂梁结构的完美替代品。这是由于它们倾向于提供均匀的应变分布，这在与梁耦合时增强了压电 (PZT) 电荷的产生。由于 PZT 产生的电压在很大程度上取决于基板的几何形状，因此需要在实际实施之前通过公式来分析垫片的行为。在本文中，开发了分析和有限元模型来研究非棱柱形梁的偏转和应变分布，称为楔形边缘悬臂梁 (WEC)，用于贴片式收割机应用。这些分析提供了最大限度地利用沿梁跨度的应变位置以实现高效收割机设计的可能性。研究了具有部分覆盖的 PZT 材料的 WEC 梁的振动能量收集特性，形成三种配置，即：Config1、Config2 和 Config3。数值和实验结果均表明，具有宏观纤维复合材料 (MFC) 作为覆盖确定的最佳应变位置的 PZT 材料的 Confg3 产生的峰值输出电压是 Config1 和 Config2 的 2 到 3 倍，MFC 键合在非最佳位置。