Modeling deformation and flow of disordered materials

Disordered, glassy materials are arguably one of the least understood states of condensed matter, Yet, they are ubiquitous in everyday life (polymers, "soft" glasses such as toothpaste, various emulsions, pastes, and foams) and in demanding applications (metallic glasses). Much of what is known about this important class of materials has been the result of truly concerted experimental and molecular modeling efforts. It is now generally accepted that amorphous materials exhibit dynamic and mechanical heterogeneities, but efforts to incorporate these into truly multiscale modeling approaches have been limited. This article describes the current state of affairs, along with many of the challenges that must be met to arrive at a fundamental understanding of amorphous materials and their response to external stresses.