A computational framework based on 3D microstructure modelling to predict the mechanical behaviour of polycrystalline materials

Abstract

In this work, a computational framework is proposed to predict the microstructure sensitive mechanical behaviour of polycrystalline materials i.e., fatigue crack initiation life and anisotropic deformation behaviour. A methodology is developed to generate 3D microstructural RVEs using Laguerre tessellation technique in Abaqus software at a particular location of the component. In any commercial software (Abaqus), the modelling of morphology of 3D polycrystalline microstructures is quite challenging due to the complex geometries of grains, and large number of interfaces or grain boundaries, however it can be achieved efficiently and automatically with the developed methodology. The continuum damage mechanics based elasto-plastic constitutive model is used to predict the microstructure sensitive fatigue crack initiation life of titanium alloy notched specimens. To capture an accurate fatigue response, damage coupled elasto-plastic constitutive equations are implemented via user defined material subroutine UMAT. The predicted fatigue crack initiation lives show good agreement with the experimental data. To further showcase the application of the developed framework, an anisotropic analysis is performed by generating 3D polycrystalline microstructure of β-titanium alloy. The developed methodology enhances the capabilities of commercial software in the field of microstructure modelling of complex problems.