Woodruff School of Mechanical Engineering

COE/Structural Mechanics Seminar


Wave propagation in meta-materials and structures: Beyond conventional limitations


Dr. Raj Pal


Georgia Tech - Aerospace Engineering


Thursday, June 8, 2017 at 1:00:00 PM


MRDC Building, Room 4211


Michael Leamy


Meta-materials and meta-structures are artificially engineered structures designed to exhibit properties not found in conventional materials. By careful design, one can obtain unprecedented control over various physical properties. Examples in mechanics includes structures having unique wave steering properties, lightweight and multi-functional capabilities with potential applications in diverse areas like impact protection, reconfigurable structures, noninvasive surgery and energy harvesting. In this talk, I will illustrate our work on two classes of meta-materials: granular lattices and topologically protected lattices. Granular media have unique mechanical properties due to the discrete and nonlinear nature of inter-particle interactions. I will show how packed lattices of elasto-plastic granules have very distinct wave propagation behavior compared to their continuum counterparts. Plastic dissipation of 3D granular packings under impact loads, their associated scaling laws and implications for stress wave mitigation will be discussed. Topologically protected edge modes allow for one-way wave propagation along the boundary, immune to the presence of defects in the body. Originally discovered in quantum systems, they also arise in other areas of physics. Here, I will outline a general procedure that we developed for designing elastic lattices supporting one-way propagation in thin elastic plates. Finally, I will present my future research vision on how the interplay between large deformation, wave propagation and topology can be exploited to address challenges arising in diverse areas ranging from soft robotics to cell biology to energy and security.


Raj Kumar Pal holds a PhD in Theoretical and Applied Mechanics from the University of Illinois at Urbana Champaign. He earned his Bachelors and Masters Degrees, both in mechanical engineering, from the National Institute of Technology, Trichy and the Indian Institute of Science, Bangalore, India, respectively. He is currently a postdoctoral fellow at the School of Aerospace Engineering at the Georgia Institute of Technology. His research interests include wave propagation, developing meta-materials, constitutive modeling and finite element methods.


Refreshments will be served.