Guoliang Huang, Xinao Chair Professor in Peking University’s Department of Mechanics and Engineering Science, will give a talk titled “A Polar Medium from Transformation Elasticity: Microstructure Design and Elastodynamic Applications.”
Abstract
While transformation optics and acoustics have made great strides, their elastic counterpart remained impeded by its tensorial character. Indeed, starting with a standard elastic material and applying a curvilinear change of coordinates, the outcome Lagrangian did not seem to correspond to any known elastic materials. This problem is known as “form invariance” (or lack thereof). In this talk, we report on the first designs of elastic materials whose Lagrangians are form invariant. Such materials are “polar” in the sense that they exhibit torque-induced asymmetric Cauchy stresses. They are also “degenerate” in that they admit stressless deformation modes. We explore recent theoretical progress of the polar medium, from orthotropic to isotropic cases, and conduct numerical and experimental demonstrations of perfect elastic wave cloaking. Under general transformation, discrete transformation theory will be introduced to design anisotropic polar solids from the bottom up as architected lattice-based materials. The key idea is to let the geometric transformation operate not only on the elastic properties, but on the underlying lattice-based architecture of the solids. Finally, some promising elastodynamic applications beyond cloaking behavior will be discussed such as arbitrary waveguiding, wave mode conversion and wave steering.
Bio
Guoliang Huang is currently a Xinao Chair Professor of the college of engineering at Peking University. He received his PhD degree from University of Alberta, Canada in 2004. Huang’s research interests include wave propagation and mechanics in elastic/acoustic metamaterials and structural materials, active mechanics, topological wave mechanics, structural dynamics, vibration and sound wave suppression. His research has been funded by NSF, Air Force Office of Scientific Research, Army Research Office, Office of Naval Research, DURIP, Department of Energy, NASA, and major industries. He has authored one book, seven book chapters, and more than 170 journal papers (included in Nature Reviews Materials, Nature Communications, Proceedings of the National Academy of Sciences, Advanced Materials, Physical Review Letters, Journal of Mechanics and Physics of Solids, et al.), with more than 12,500 Google citations and H-index of 63. He is one of the top 2% scholars at Stanford. He is the Associate Editor of Wave Motion, Associate Editor of the ASME Journal of Vibration and Acoustics, the field Editor-in-Chief of Frontiers in Physics, and serves on the editorial broad in many other journals. He is a fellow of the SPIE, and a fellow of the IAAM.