This award supports theoretical atomic-scale modeling of fracture and plastic deformation of solid materials. The goal of this proposal is to learn the connection between interatomic forces and the behavior of materials during brittle fracture. Most of the project effort will be focused on silicon as a test case. Analytic and numerical methods will be used in close coordination with an ongoing experimental program. The analytical methods include techniques for solving dynamical lattice models of fracture, while the numerical methods include molecular dynamics code written for high-performance computing systems and designed to study fracture. Experimental work in this area is supported by DMR in the Ceramics Program. %%% This award supports theoretical atomic-scale modeling of fracture and plastic deformation of solid materials. One of the central goals of materials physics is to relate the nanometer-scale interactions between atoms to observed physical properties at the macroscopic scale. Fracture and plastic deformation in solids is one of the particularly difficult physical effects to model because they involve dynamics of defects of great complexity-rapidly moving structures with characteristic dimensions as large as meters but controlled by atomic-scale processes. The goal of this effort is to show that a quantitative connection between atomic and macro scales is possible, and that atomic-scale simulations can be used for detailed predictions of realizable laboratory experiments. The project will focus on brittle fracture, with additional work on ductile fracture and plastic deformation. Experimental work in this area is supported by DMR in the Ceramics Program. ***
