Bridging the Nano to Macro
Scale Gap

The world relies on materials scientists and engineers to predict the behavior of materials, especially their performance and failure under stress. Washington State University professor Hussein M. Zbib is helping scientists and engineers to understand the problematic behavior of materials at the nano and micro scales.

Zbib has collaborated with Tomas Diaz de la Rubia of Lawrence Livermore National Laboratory to develop an innovative scientific framework that gives scientists and engineers the ability to examine a "broad range of problematic phenomena in materials science and mechanics." As advances in science and nanotechnology help electronic components, sensors, and mechanical devices become smaller, predicting the behavior of the materials used to make them becomes more difficult. The behavior of a material when its quantity can be measured a molecule at a time often differs vastly from the behavior of the same material in bulk.

Zbib and de la Rubia have combined new techniques and existing methodologies to yield a model that is more complex-and more powerful-than those generally used. Their system integrates a continuum model predicting the growth pattern of crystalline materials with a numerical model called micro3D that accounts for defects in generally homogeneous material. Their integrative model makes it possible to examine the ways in which many different possible defects in materials may interact, thus predicting the materials’ strength and possible means of failure.

In a Web commentary on their article, Zbib and de la Rubia write that their work is "part of a larger effort" in which Lawrence Livermore National Laboratory and several universities are collaborating to develop a set of "multiscale models that can predict the behavior of matter under an extremely wide range of conditions and at length scales ranging from nanometers to macrometers."

Zbib and de la Rubia are focusing on using molecular dynamics and dislocation dynamics to predict the mechanical properties of various microstructures. Their goal is to provide scientists and engineers with a way to link the molecular scale of developing nanostructures to the mesoscopic scale of the miniature devices nanotechnology is helping to create. Their work predicts how molecules interact within a micro (or nano) structure, then takes the additional step of enabling researchers to predict the mechanical properties of the resulting structure.

Their paper on their work is one of the most highly cited in the field of engineering, according to ISI Essential Science Indicators. Titled "A Multiscale Model of Plasticity," it was published in the International Journal of Plasticity in 2002. For more on Zbib, explore the WSU website or see the source of this article: Fast Moving Fronts Comments, ESI Special Topics , September 2004.