Nanostructures are devices built on an extremely tiny scale - a nanometer is one-billionth of a meter. Materials at this scale show unique properties that affect how they behave. These properties mean than nanomaterials may be useful for novel and interesting applications, but we need to understand how to work with them and how they will react.
One feature of nanomaterials is that they seem to have a random (stochastic) response when subjected to external loading. In a recent paper that appeared in the Proceedings of the National Academy of Science of the USA, two MSI Principal Investigators, Associate Professor Ryan Elliott and Professor Ellad Tadmor, worked with Subrahmanyam Pattamatta to investigate this behavior. The authors are in the Department of Aerospace Engineering and Mechanics in the College of Science and Engineering. Because standard simulation methods are insufficient to deal with the complex behavior of nanomaterials, the authors developed a new method to simulate this behavior. They created an equilibrium map (EM) that characterizes the material's responses. This EM-based approach allows for simulation of nanostructure experiments. The paper shows how the method works in the case of a nanoslab of nickel. The paper can be found on the PNAS website: Pattamatta, Subrahmanyam, Ryan Elliott, and Ellad Tadmor. 2014. Mapping the stochastic response of nanostructures. Proceedings of the National Academy of Science of the USA 111(17):E1678-E1686. Published online before print.
Professor Elliott and his research group use MSI for research into objective structures using a parallel code. The group is investigating the scalability and performance of the code. Professor Tadmor and his group are developing an optimal and parallel version of the quasicontinuum method, which is a multiscale technique based on the idea of representative atoms and finite element interpolation.
Image description: A schematic of the possible behaviors of a compressed nickel nanoslab. As the compression increases with time, the initially perfect structure (bottom) develops defects associated with minima on its evolving potential energy surface. The sequence of states observed in repeated experiments on nominally identical nanostructures is highly stochastic and rate dependent. Each colored line in the figure represents one such realization obtained using a new computational method described in the paper by S. Pattamatta et al.. Image courtesy of Subrahmanyam Pattamatta, Ryan Elliott, and Ellad Tadmor.
posted on July 23, 2014