Energetic stability and structural admissibility in granular systems

This preprint presents a minimal state-based energetic formulation for the stability of granular assemblies. The system is described by porosity and a structural parameter representing contact-network admissibility, allowing stability to be interpreted in terms of the existence of admissible configurations. The formulation establishes a direct connection between coordination, contact-network structure, and energy-based descriptions of granular systems. Stability corresponds to the existence of a local minimum of a scalar state function, while instability arises when this minimum disappears. The present version is restricted to dry granular assemblies and focuses on the structural origin of stability in the absence of fluid coupling. The manuscript has been submitted to Granular Matter for peer review.