Dynamic coupling of a finite element solver to large-scale atomistic simulations

We propose a method for efficiently coupling the finite element method with atomistic simulations, while using molecular dynamics or kinetic Monte Carlo techniques. Our method can dynamically build an optimized unstructured mesh that follows the geometry defined by atomistic data. On this mesh, different multiphysics problems can be solved to obtain distributions of physical quantities of interest, which can be fed back to the atomistic system. The simulation flow is optimized to maximize computational efficiency while maintaining good accuracy. This is achieved by providing the modules for a) optimization of the density of the generated mesh according to requirements of a specific geometry and b) efficient extension of the finite element domain without a need to extend the atomistic one. Our method is organized as an open-source C++ code. In the current implementation, an efficient Laplace equation solver for calculation of electric field distribution near rough atomistic surface demonstrates the capability of the suggested approach.Peer reviewedPeer reviewe

Visualização automatica de complexos celulares arbitrarios

Orientador: Jorge StolfiDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Ciencia da ComputaçãoResumo: Um complexo celular bidimensional é uma subdivisão de uma superfície num número fi­nito de elementos - faces (discos abertos), arestas (curvas abertas) e vértices (pontos). Descreve-se aqui um programa que, dada apenas a estrutura topológica de um complexo celular (ou seja, as relações de incidência e adjacência entre seus elementos), determina uma representação geométrica do mesmo (uma superfície subdividida), que é "bonita" e permite visualizar facilmente a topologia do complexoAbstract: A two-dimensional cell complex is a partition of a surface into a finite number of elements faces (open discs), edges (open curves) and vertices (points). Here, is described a program which given only the topological structure of a cell complex (that is, the incidence and adjacency relationships between its elements), constructs a geometric representation of it - a subdivided surface - which is "nice looking" and allows one to clearly visualize the topology of the complexMestradoMestre em Ciência da Computaçã