Wednesday, September 13, 2017
2:30pm - 3:45pm
107 Surge Building - VT Campus
Dr. Xiaoyu (Rayne) Zheng
Department of Mechanical Engineering
Few solid materials exist considerably lighter than water. To decrease the density beyond this point, materials must have a porosity, which generally comes at the cost of a disproportional degradation of other desirable properties. For example, graphene aerogels have among the lowest record densities ~1kg/m3, but their strength have been degraded to tens to hundreds of Pascal (<10-8 of that of graphene). The attainment of low density has come with a price --- significant reduction of bulk scale properties.
3D architected metamaterials are among the lightest man-made materials created to date yet with exceptional strength and stiffness. Their performance is attributed to the hierarchical layout of architectures from nanometers to tens of centimeters and above. I will discuss a suite of novel additive micro- and nanoscale additive manufacturing technologies that have been developed in our group to enable fast manufacture of these architected materials in polymer, metals, ceramics and biocomposites. Attention is focused on the mechanical benefit of multi-scale nano-structured layout that spans over seven orders of magnitude in lengthscales. With the possibility of incorporating precise control of topological architectures across unprecedented disparate length-scale sets, we enter into a paradigm where nanoscale material properties can be harnessed and made accessible in large scale objects, breaking the critical trade-off in mechanical properties, such as density, strength and damage tolerance, opening a wide range of applications in structural, bio and electronics applications.
Xiaoyu (Rayne) Zheng has been an Assistant Professor of Mechanical Engineering and directs the Advanced Manufacturing and Metamaterials Laboratory at Virginia Tech since December 2015. He holds an affiliate position at the Macromolecules and Innovation Institute and Department of Materials Science and Engineering at Virginia Tech. Prior to joining Virginia Tech, from 2011 to 2015, he had been a Member of Technical Staff and Principle Investigator at DOE Lawrence Livermore National Laboratory, California, where he worked on high volume additive manufacturing initiatives and materials with controlled micro-architectures (DARPA MCMA). He received his Ph.D. degree in Mechanical Engineering from Boston University in 2011 with the Outstanding Dissertation Award. He and his team had developed the world's lightest materials capable of holding more than 160,000 of their own weight with a mass density as light as aerogels. Zheng has published over 40 journal articles, proceeding papers and book chapters, including his first authored articles being featured at the front covers on Science Magazine and Nature Materials. His work on Micro/nano 3D printing and architected metamaterials has been selected as top 10 innovations of 2015 by MIT Technology Review. He received ICTAS Junior Faculty Award, Inventor of the Month, Best Paper Award at IEEE Sensor Conference and Director’s Publication Excellence Award at Lawrence Livermore National Laboratory. His work has been widely reported by R&D Magazine, Materials Today, Nano Today, MRS Bulletin, American Physics Society etc.