Granular Micromechanic-Based Non-Homogeneous Numerical Simulations for Ultra-High-Performance Fiber-Reinforced Concrete (UHP-FRC) in Compression, Tensile and Three-Point Bending Tests with Loading and Unloading Pattern

This study presents a granular micromechanics-based model for predicting the mechanical response of Ultra-High Performance Fiber-Reinforced Concrete (UHP-FRC) under various loading conditions (compression, tension, and bending) in non-homogeneous con`gurations. The model simulates loading- unloading cycle, elastic response, and grain-pair interactions to capture anisotropic behavior. It links microstructural mechanisms to material performance using Piola’s ansatz and derives damage and plasticity evolution from Karush–Kuhn–Tucker conditions [1]. Implemented in MATLAB and coupled with COMSOL, the model is validated against experimental data and used for parametric analysis. The granular micromechanics approach (GMA) offers a computationally feasible alternative to atomistic methods, predicting phenomena like anisotropy and directional damage evolution. It supports higher-gradient continuum theories to capture strain localization and emergent behaviors [2]. ́ [1] E. Barchiesi, A. Misra, L. Placidi, and E. Turco. Granular micromechanics-based identi`cation of isotropic strain gradient parameters for elastic geometrically nonlinear deformations. (ZAMM-Journal of Applied Mathematics and Mechanics / Zeitschrift für Angewandte Mathematik und Mechanik, 2021). [2] Francesco dell’Isola, Massimo Guarascio, and Kolumban Hutter. A variational approach for the deformation of a saturated porous solid. a second-gradient theory extending terzaghi’s effective stress principle. (Archive of Applied Mechanics, 2000