ME Seminar - Mechanism-based Elastic Metamaterials for Broadband Wave Control and Vibration Isolation

Guest Speaker: Prof. ZHU Rui

Department of Mechanics
Beijing Institute of Technology

Rui ZHU is a Professor at the Department of Mechanics, School of Aerospace Engineering, Beijing Institute of Technology, China. He received his PhD at University of Arkansas at Little Rock in 2013. He was also a Postdoctoral Fellow and later on, a Research Associate at North Carolina State University in 2014, University of Missouri in 2015 and University of Washington in 2016. His focus of study is elastic/acoustic metamaterials and their applications in wave/vibration control. He has published over 70 peer-reviewed journal papers in Nature Communications, Science Advances, etc., including 4 ESI Highly Cited Papers. Currently, he is a Fellow of the Chinese Society of Theoretical and Applied Mechanics (CSTAM) and a Fellow of the Chinese Society of Metamaterials. 

Unlike classic elastic materials which generally exhibit six orthogonal eigenmodes of deformation, mechanism-based elastic metamaterials can be engineered to have a number of “zero modes”, deformation modes that cost little to no elastic energy. In fact, the number of zero modes can alter the ordinary elasticity tensor from the state of null-mode (solid-state) to the states of uni-mode, bi-mode, tri-mode, quadra-mode, penta-mode and the state of hexa-mode (near-gaseous state), which brings peculiar wave control abilities in a broad frequency band, such as perfect underwater acoustic cloak and negative reflection. First, we show an 3D mechanism-based metamaterial design with reconfigurable number of zero modes, and experimentally demonstrate its transformability ranging from all seven types of extremal metamaterials. Various interesting elastic wave controls are further investigated in 1D-, 2D and 3D-systems. In the second part of the talk, we explain an integrated design of metamaterial with quasi-zero stiffness (QZS) which is normally achieved through assembled mechanisms. Broadband vibration isolation applications are then demonstrated with the lightweight metamaterial.