Abstract:

Elastic metamaterials (EMMs) with artificially engineered microstructures possess some unique properties including negative refraction, negative modulus, negative effective density, to name a few. Researchers have been attracted to explore the applications of EMMs for various kinds of purposes, one of which is low frequency vibration suppression. The ability of EMMs for vibration suppression arises from their band gap phenomenon due to the out-of-phase motion of the introduced microstructures (local resonance). On the other hand, the applications of EMMs have also been extended into the field of energy harvesting by integrating certain energy transduction components, such as, piezoelectric transducers.

In this seminar, I will talk about the recent work in our group on the modelling and design of piezoelectric metamaterial / metastructure systems to achieve multi-functionalities: vibration suppression and energy harvesting. First, I will cover the simplified lumped parameter model of piezoelectric metamaterial systems and the corresponding distributed parameter model of piezoelectric metamaterial beams. The later represents a more practical implementation. Then, I will introduce the design of a modified metamaterial system with internally coupling springs to achieve multiple band gaps for wideband vibration control. The corresponding distributed parameter model of piezoelectric metamaterial beam with internal coupling is also developed and the benefits for both vibration suppression and energy harvesting will be discussed. Finally, I will introduce our very recent effort in the modelling of a piezoelectric phononicmetamaterialbeam, which possesses both Bragg Scattering band gap and local resonance induced band gap. A one-dimensional piezoelectric composite finite element is derived and the predicted transmittance from our FE model confirms the existence of two types of band baps and demonstrates the influence of piezoelectric effect on the band gaps and energy harvesting performance.

学者简介：

   汤丽华博士目前是新西兰奥克兰大学机械系高级讲师。他于2005年和2008年在上海交通大学获得工程力学工学学士和固体力学工学硕士，于2012年在新加坡南洋理工大学获得结构与力学工学博士学位。他已发表期刊和会议论文超过70余篇，引用超过1800次 (谷歌学术)。他目前的研究兴趣有：能量回收、智能材料和结构、振动和噪声控制、非线性动力学、声学超材料、热声发动机、以及微机电系统。他目前是ASME “能量回收”技术委员会成员和ASME “自适应结构和材料系统”技术委员会成员。