Physical regularities of the influence of filler characteristics on tribological properties of polymer nanocomposite

The paper analyzes the patterns of influence of the characteristics of silica nanoparticles on the friction coefficient and wear parameters during friction of a polymer nanocomposite (PNC) on a steel counterbody. The studies were performed theoretically using the method of movable cellular automata and experimentally according to the "block-on-ring" scheme. The size and shape of silica nanoparticles and the sliding velocity were varied. The model also took into account the temperature dependence of the mechanical properties of materials. It was found that the low friction properties of PNC are caused by changing the mechanical properties of the materials of a transition tribolayer under conditions of frictional heating. It was shown also that the size of the nanofiller affects the stability of friction and wear mode.

Simulating Self-Regeneration and Self-Replication Processes Using Movable Cellular Automata with a Mutual Equilibrium Neighborhood

This paper deals with the issue of model construction of the self-regeneration and self-replication processes using movable cellular automata (MCAs). The rules of cellular automaton (CA) interactions are found according to the concept of equilibrium neighborhood. The method is implemented by establishing these rules between different types of cellular automata (CAs). Several models for two- and three-dimensional cases are described, which depict both stable and unstable structures. As a result, computer models imitating such natural phenomena as self-replication and self-regeneration are obtained and graphically presented.

Abstract Methods on Mesoscopic Scales of Friction

In recent years, research has increasingly focused on the complex processes involved in friction contacts. Especially in tribological high-loaded contacts, characterized by the presence of contact modifying wear particles, macroscopic friction shows a surprisingly high dynamic complexity on many temporal and local scales. There are dominant effects on mesoscopic scales such as the geometric self-organization structures of the wear dust in the contact, which can significantly change the local contact surfaces. For the description and simulation of these phenomena, abstract methods have shown their effectiveness. One class of methods are cellular automata, both volume- and particle-based. The latter are in particular the Movable Cellular Automata developed by Sergey Psakhie. The scales of these discrete methods are freely selectable in wide ranges between the macro world and the atomic scale. Nevertheless, they provide reliable information on mesoscopic balances in the boundary layer and thus also on the macroscopic behavior of the tribocontact. The success of these methods is shown by the example of an automotive brake. The question of the relative insensitivity of the scales of these mesoscopic methods is examined in detail.

Development and research of drone swarm control via methods borrowed from continuum mechanics

For a drone swarm in the form of a linear chain, there was solved a problem of maintaining the initially specified shape throughout the entire time of movement. To build a mathematical model of the drone chain, we applied the theory of movable cellular automata. By increasing the amount of elements in the chain, we obtained equations of oscillations of the chain in the longitudinal and transverse directions, similar to the equations of the longitudinal oscillations of the rod and the transverse oscillations of the tensioned string. We studied the longitudinal and transverse oscillations of the resulting system, resulting from the external disturbances, as well as the influence of these oscillations on the stability. Oscillation damping has been introduced, both in the longitudinal and transverse directions. Findings of research show that if damping is not introduced, it is not possible to maintain the drone formation using this method, i.e. the instability of the swarm motion process is emphasized. This problem is solved by introducing damping in the longitudinal and transverse directions, with damping in the longitudinal direction playing an important role.

The study of the dependence of mechanical properties and fracture of water-saturated high-strength concrete on the parameters of pore structure

Based on the hybrid numerical method, namely, the hybrid method of movable cellular automata, we developed a computer-based two-scale mechanical model of heavy water-saturated concrete. The model takes into account the content of the liquid phase and its redistribution in networks of microscopic and capillary pores. The features of deformation and fracture of concrete samples under uniaxial compression were numerically studied in a wide range of variation of the macroscopic characteristics of the pore space, viscosity of an interstitial liquid and loading rate. Simulation results confirmed the possibility of a unified description of the dependence of the strength of heavy concrete on the sample permeability and size, fluid viscosity and the loading rate in terms of the complex dimensionless parameter that combines these characteristics.

The development of the formalism of movable cellular automata for modeling the nonlinear mechanical behavior of viscoelastic materials

The paper is devoted to the development of the formalism of the computational method of discrete elements (DEM) for describing the mechanical behavior of consolidated viscoelastic materials. We considered an advanced implementation of DEM, namely, the method of movable cellular automata (MCA). A feature of this implementation of DEM is the use of a generalized many-body formulation of the relations for the forces of element-element interaction. 3D numerical models of viscoelastic material with a spectrum of relaxation times (Kelvin and Maxwell models, the standard model of elastomers, and others) were developed within the formalism of MCA. The correctness of the developed discrete element formalism and its applicability for modeling the processes of deformation and fracture of viscoelastic materials under dynamic loading are shown using the standard model of elastomers as an example. The relevance of the results is determined by the prospects for the further development of DEM and its application to study and predict the mechanical response of viscoelastic materials of various nature under dynamic loading including contact problems.