Dr. Bing Li is a professor in the School of Aeronautics at Northwestern Polytechnical University. He conducted his Post-Doctoral training in 2015-2018 at The University of Akron (Akron, US). He obtained his Ph.D. in the College of Engineering at Peking University (Beijing, China) in 2015. He received his Joint-Supervision Ph.D. training in the School of AMME at The University of Sydney (Sydney, Australia) in 2013-2014. Dr. Li's primary research interests lie in the field of elastic/ mechanical metamaterials, wave propagation and vibration control, structural health monitoring and advanced composites design. He has published over 60 research articles in the prestigious journals and has presented his work at a number of renowned conferences around the world.

Speech Title: Design and applications of elastic meta-structures

Abstract: Vibration and elastic-wave manipulations at sub-wavelength scale have been realized by using elastic metamaterials. However, most of the existing metamaterial designs are still suffering from fundamental limitations including large volume, narrow operating bandwidth and unadjustable functionalities. How to realize efficient elastic-wave and vibration control in a compact-footprint, broadband and tunable strategy has been a challenge. In this report, a series of elastic meta-structures (metamaterials and metasurfaces) are introduced for broadband vibration-suppression and extraordinary wavefront manipulation. Specifically, a double zero-index metamaterial is proposed to achieve two separated elastic-wave Dirac-like cones at the Brillouin zone center, which is further applied for wave-front shaping and perfect tunnelling. Furthermore, requiring neither active control nor nonlinear effect, a couple of diatomic metamaterials and ultrathin lossless metasurface are designed for highly efficient asymmetric-transmission within a wide frequency range. Also, combining the shape memory effect and programmable design, a 4D printed metamaterial concept is further proposed for self-adaptive bandgap shift and programmable waveguide channels. The efficient, robust and broadband capabilities of tailoring vibration and elastic-wave in compact and lightweight meta-structures are systematically verified by theoretical analysis, numerical simulation and experimental measurements. The proposed designs pave feasible ways for noise and vibration control in elastodynamics.