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Particle-based modeling of the mechanical behavior of porous fluid-saturated viscoelastic solids

Shilko, Evgeny V.; Dimaki, Andrey V.; Popov, Valentin L.

FG Systemdynamik und Reibungsphysik

In the paper, we developed a macroscopic discrete element model of permeable fluid-saturated materials with solid skeleton characterized by viscoelastic rheological properties. The Biot's linear model of poroelasticity was used as a mathematical basis for describing the mechanical interrelation between the solid skeleton and interstitial fluid. Using this model, we numerically studied the dependences of the effective Young's modulus and strength of fluid-saturated viscoelastic materials on the loading rate, sample size and the mechanical parameters, which determine the relaxation time of the solid-phase skeleton and the time scale of redistribution of fluid in the pore space. We revealed two dimensionless control parameters that determine the dynamic values of the effective mechanical characteristics of the samples under compression loading. We obtained the general relations that describe the above-mentioned dependences in terms of the two proposed control parameters. These relations have a logistic nature and are described by sigmoid functions. The importance of the proposed empirical expressions is determined by the possibility of their application for predicting the mechanical response of fluid-saturated materials of different nature (bone tissue, rocks, porous materials with polymeric skeleton, including elastomers, etc.) under dynamic loading.