This is a grant funded in response to a (small) proposal submitted to the Information Technology Research (ITR) Initiative. The research will be done in collaboration with groups at Lawrence Livermore National Laboratory (LLNL) and Oxford University (England).
Three-dimensional simulations are increasingly providing a powerful information-based approach to both material processing and the design and manufacturing of components that support a wide range of technologies. The objective of this research, which focuses on phenomena that involve large plastic deformations of metallic materials, is to develop a physics-based methodology for accurate modeling. At the overall system level, i.e., microstructural in the case of materials processing or components under complex loading, both Lagrangian and Arbitrary Lagrangian-Eulerian (ALE) finite element implementations are the computational basis of most software. However, unique unit processes that arise at atomic and molecular scales often control critical phenomena, and this is where many models are significantly deficient. In particular, nearly all inelastic simulation codes are limited to a narrow class of crystalline materials, namely those that are close-packed which primarily includes face-centered-cubic (fcc) materials. There is a challenge to develop accurate models for a broader range of engineering materials and to adapt these models into current large-scale finite element, hydrodynamic, and dislocation dynamics codes. The focus of this research is on the development of multiscale models and algorithms for the accurate and verifiable simulation of the deformation behavior of metallic materials possessing complex - non-planar - dislocation core structures.
The research focuses on the relationship between the three-dimensional atomic configurations of defects, their mobility, and macroscopic plastic flow. The multiscale methodologies to be developed will be applicable to many areas, including problems in nanotechnology. The principal goals are: (1) to develop a rigorous methodology to link theories at scales ranging from electronic and atomic through mesoscale and macroscopic; (2) to develop physically-based continuum constitutive relations that account for complex phenmonea arising from non-planar dislocation cores; and, (3) to explore the effects of such defects on critical phenomena such as strain localization and fracture. We will consider a range of technologically important materials from different crystal classes and under conditions that arise in both material processing and in components subjected to mechanical loading.
The algorithms to be developed will be ready for installation into large-scale finite element codes, e.g., Abaqus, both for polycrystals in nanoscale regimes and macroscopic components. Although the structure of the constitutive relations will be significantly different from those currently in use, implementation in massively parallel codes will be straightforward. %%% This is a grant funded in response to a (small) proposal submitted to the Information Technology Research (ITR) Initiative. The research will be done in collaboration with groups at Lawrence Livermore National Laboratory (LLNL) and Oxford University (England).
The research focuses on the relationship between the three-dimensional atomic configurations of defects, their mobility, and macroscopic plastic flow in metallic materials. The multiscale methodologies to be developed will be applicable to many areas, including problems in nanotechnology. The principal goals are: (1) to develop a rigorous methodology to link theories at scales ranging from electronic and atomic through mesoscale and macroscopic; (2) to develop physically-based continuum constitutive relations that account for complex phenmonea arising from non-planar dislocation cores; and, (3) to explore the effects of such defects on critical phenomena such as strain localization and fracture. We will consider a range of technologically important materials from different crystal classes and under conditions that arise in both material processing and in components subjected to mechanical loading. ***
