Research Projects

The mechanical response of amorphous solid materials, such as foams, gels, colloids, and metallic glasses, is a significant research field in material science, engineering, and the physics of disordered systems. Topological defects can explain plastic deformation and flow in crystalline solids, but no such framework works for amorphous solids due to their aperiodic nature and symmetry. The shear-transformation-zone (STZ) theory is one of the theoretical and experimental approaches to explain the failure mechanism in glass-forming materials. STZs are microstructural defects where plastic deformation occurs in glasses, but their precise nature remains unknown. Local structure plays a crucial role in governing the physics of mechanical yielding in amorphous solids. For example, metallic glasses have densely close-packed structures, causing localized plastic instabilities during shear. In contrast, attractive colloidal gels or polymer gels exhibit open percolated network-type structures. Elementary plastic events occur through bond-breaking events during shear deformation. This project aims to study the effect of local structure on the universality of failure mechanisms and mechanical properties of different categories of disordered solids. The modified Stillinger-Weber (mod-SW) potential, consisting of an isotropic two-body u? term and a scaled anisotropic three-body u? term, provides an ideal platform to alter interaction to generate desired glassy configurations. Using computer simulation, the project aims to investigate the consequences of varying the tetrahedrality parameter on elementary plastic events in a shear experiment and understand how microstructural defects change their nature from STZ to bond-breaking events.