Multiscale Characterization and Domain Partitioning for Multiscale Analysis of Heterogeneous Materials

Abstract

This chapter discusses the development of a multiscale characterization methodology leading to microstructural morphology-based domain partitioning MDP methodology for materials with nonuniform heterogeneous microstructure. The comprehensive set of methods is intended to provide a concurrent multiscale analysis model with the initial computational domain that delineates regions of statistical homogeneity and inhomogeneity. The MDP methodology is intended as a preprocessor to multiscale analysis of mechanical behavior and damage of heterogeneous materials, e.g., cast aluminum alloys. It introduces a systematic three-step process that is based on geometric features of morphology. The first step simulates high-resolution microstructural information from low-resolution micrographs of the material and a limited number of high-resolution optical or scanning electron microscopy micrographs. The second step is quantitative characterization of the high-resolution images to create effective metrics that can relate microstructural descriptors to material behavior. The third step invokes a partitioning method to demarcate regions belonging to different length scales in a concurrent multiscale model. Partitioning criteria for domain partitioning are defined in terms of microstructural descriptors and their functions. The effectiveness of these metrics in differentiating microstructures of a 319-type cast aluminum alloy with different secondary dendrite arm spacings SDAS is demonstrated. The MDP method establishes intrinsic material length scales and consequently subdivides the computational domain for concurrently coupling macro- and micromechanical analyses in the multiscale model. Finally, a multiscale analysis of ductile fracture is conducted using a differentiated scale structure that has been laid out by the MDP algorithm. The chapter emphasizes the need for coupling multiscale characterization and domain decomposition with multiscale analysis of heterogeneous materials.