SUMMARY
In recent years, a new framework called Materials Knowledge Systems (MKS) has been formulated for establishing highly accurate metamodels for localization (opposite of homogenization) linkages in hierarchical materials systems. These computationally efficient linkages are designed to capture accurately the microscale spatial distribution of a response field of interest in the representative volume element (RVE) of a material, when subjected to an imposed macroscale loading condition. In prior work, the viability and computational advantages of the MKS approach were demonstrated in a number of case studies involving multiphase composites, where the local material state in each spatial bin of the RVE was permitted to be any one of a limited number of material phases (i.e., restricted to a set of discrete local states of the material). In this study, we present a major extension to the MKS framework that allows a computationally efficient treatment of significantly more complex local states of the material. In this study, we present an important extension of the MKS approach that permits calibration of the influence kernels of the localization linkages for an entire class of low to moderate contrast material systems as opposed to the prior protocols that addressed one material system at a time. For high contrast single phase and multi-phase polycrystals, the MKS series include higher order terms. These major advances in the MKS framework are facilitated by the use of suitable Fourier representations of the influence functions. This study describes this new formulation and the associated calibration protocols, and demonstrates its viability with case studies of different material systems.