Numerical evaluation of micropolar elastic parameters for a heterogeneous microstructure

Materials that, like concrete, possess a heterogeneous microstructure, are characterized by behaviours at the macroscale that are difficult to be represented with standard continuum descriptions. Generalized continua models, due to their enriched kinematical description, are well-suited for the representation of microstructural effects. The main limitation to the use of generalized models is the presence of additional material parameters, difficult to be obtained through experiments. The present work deals with the definition of the two additional parameters of the micropolar continuum theory, using a numerical homogenization strategy. The main aim is, then, to obtain an equivalent micropolar macromedium starting from a random heterogeneous microstructure. This paper focuses on a homogenization strategy originally conceived for periodic microstructures, and presents a preliminary investigation on its extension to randon heterogeneous microstructures. The theoretical aspects are discussed, and some initial numerical results are presented.