Purpose. To evaluate the change in free energy in the transition from the nonequilibrium state of the rock to the equilibrium. This process implements the process of dynamic brittle fracture on the structural defects of the rock as a micro-inhomogeneous medium. Methodology. It included conducting, within the framework of statistical thermodynamics, a series of experimental studies on the density and velocity of propagation of longitudinal and transverse acoustic waves in sandstone samples under different loading conditions. Findings. According to the experimental data on the velocities of propagation of longitudinal and transverse acoustic waves for a number of sandstones at different loading modes, the values of mechanical and thermodynamic parameters characterizing the state of rocks are established. A comparative analysis of the frequency dependences of free energy on the value of the Poisson ratio is carried out. Originality. A model of a thermodynamic system is proposed that describes the energy-activated process of transition of rock from a nonequilibrium state to equilibrium during external perturbation by surface acoustic waves. The possibility of estimating the degree of slow dynamic destruction by the Debye temperature is revealed. The mechanism of dissipation of internal energy on structural defects of the system, with the transition of its part into thermal motion of structural elements, is substantiated. Practical value. The technique for investigation of thermodynamic state of non-ideally elastic rocks by methods of nondestructive testing is developed. The correlation between the mechanical parameters of the rock and the characteristics of the process of its transition from the nonequilibrium state to the equilibrium is established.

На основі моделі перколяційного кластера для металонаповнених поліуретанових ауксетиків визначено їх фрактальні розмірності та індекси перколяції. Використання фрактально-перколяційного підходу до моделі металонаповненого полімеру надало змогу розрахувати структурно-мікроскопічні (геометричні) параметри граничних і міжфазних шарів досліджуваних металонаповнених поліуретанів, а також механічні характеристики цих ауксетиків. Співставлено модельні розрахунки та експериментальні значення цих характеристик.