Amorphous Media

There exists a robust theory, built from microscopic considerations, that explains the formation, behavior, and failure of crystalline solids. The same does not hold true for amorphous solids, which are structurally disordered. Disorder profoundly affects our theoretical understanding of the mechanics of amorphous solids. In the absence of periodicity, one cannot explain the microscopic origin of elastic constants. Additionally, in the absence of long range order, the notion of a topological defect so fundamental to crystalline plasticity is rendered meaningless for amorphous solids. The disorder that imparts additional strength to amorphous solids can also lead to their catastrophic failure. At the fundamental level, the problem stands at the frontier of Condensed Matter and Non-equilibrium Statistical Physics. Given a huge fraction of materials employed in daily use (including glasses, plastics, alloys, elastomers, and other composites) are amorphous in character, understanding their mechanics and failure carries huge signficance in Materials Physics applications.

 

Within the broad theme of disorder, our primary efforts have been directed towards experiments in frictional granular jamming, fracture of interfacial particle rafts, and molecular dynamics studies in two-dimensional aggregates.