Title:Mechanics of Nanoporous Aluminum: A Molecular Dynamics Study
Speaker:Albert C. To, PhD
Department of Mechanical Engineering and Materials Science Center for Simulation and Modeling University of Pittsburgh, USA
date:March 9th 2011(Wed), 9:30AM
location:Room 1048, ICT, CAS

Abstract:
The presentation will present our recent research work on the mechanical performance of nanoporous metals, with different porosities and pore sizes, under uniaxial tensile loading using molecular dynamics (MD) simulations.
Our computational study demonstrates that softening of an open cell nanoporous (np) aluminum structure subjected to tensile loading can be significantly reduced when the size of ligaments and the joints that connect them in the structure is designed to be sufficiently small. It is found using MD simulations that the softening becomes slightly slower with increasing porosity for the structures with porosity less than or equal to 72%, and stress localization is observed during softening. In contrast, for structures with more than 75% porosity, softening is much slower, and stress delocalization occurs during softening. It is argued that at relatively high porosity, softening is governed by both the ligament size and the joint size because their compliance becomes high enough to allow the overloading stress due to ligament rupture to be redistributed more effectively throughout the structure.

bio:
Professor Albert To is currently Assistant Professor in the Department of Mechanical Engineering and Materials Science at the University of Pittsburgh. He received his B.S. and Ph.D. at University of California, Berkeley and his M.S. at Massachusetts Institute of Technology in Civil and Environmental Engineering, and also an M.S. in Earth and Planetary Science at U.C. Berkeley. He was a postdoctoral research fellow in the Department of Mechanical Engineering at Northwestern University. His research interests include computational nanomechanics and multiscale modeling and simulation. In 2009, he received the prestigious US National Science Foundation (NSF) BRIGE award.