Civil and Systems Engineering Fall Seminar Series: Guoliang Huang

Description

Guoliang Huang, Xinao chair professor of Peking University's College of Engineering, will give a talk titled "A Polar Medium from Transformation Elasticity: Microstructure Design and Elastodynamic Applications" for the Department of Civil and Systems Engineering.

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:

Huang received his doctoral degree from the University of Alberta in Canada in 2004. His 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. Huang's research has been funded by the National Science Foundation, Air Force Office of Scientific Research, Army Research Office, Office of Naval Research, Defense University Research Instrumentation Program, Department of Energy, NASA, and major industries. He has authored one book, seven book chapters, and more than 170 journal papers (include Nature Reviews Materials, Nature Communications, Proceedings of the National Academy of Sciences (PNAS), Advanced Materials, Physical Review Letters, Journal of Mechanics and Physics of Solids, and more), with more than 12,500 Google citations and an 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 American Society of Mechanical Engineers' Journal of Vibration and Acoustics, the field editor-in-chief of Frontiers in Physics, and serves in editorial broad in many other journals. He is a fellow of the SPIE, the international society for optics and photonics, and of the International Association of Advanced Materials.