ICAMS / Interdisciplinary Centre for Advanced Materials Simulation


Atomistically informed continuum models for deformation and fracture of materials

Date: 30.08.2017
Place: International Symposium on Multiscale Computational Analysis of Complex Materials, Copenhagen, Denmark

Alexander Hartmaier

In order to understand the mechanical performance of multiphase materials, which possess a heterogeneous microstructure, we need to describe the elastic-plastic deformation of all individual phases and their interfaces. It is clear that such description must involve several length and time scales. One possible approach is the bottom-up scalebridging method, in which information is gained on the most fundamental level and then this information is systematically coarse grained. In our work, we follow a complementary top-down approach in which we start from a macroscopic model that is based on physical laws in which material parameters and scaling relations obtained from atomistic simulations are incorporated. This is accomplished by introducing representative volume elements (RVE) of rather complex microstructures. This RVE-based microstructural model is then subjected to different mechanical loads and the resulting mechanical problem is solved by the Finite Element Method (FEM). In the framework, crystal plasticity models are applied to describe plastic flow on the level of individual grains. Interface properties are model by the cohesive zone method. Furthermore, damage models are applied to describe ductile failure and fatigue crack initiation. It will be demonstrated how such RVE-based micromechanical simulations can be applied to make predictions on macroscopic mechanical behavior of multiphase materials, such as plastic flow, fatigue and hydrogen embrittlement.

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