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The paper presents the movable cellular automaton method. It is based on numerical models of surface layers of the metal-ceramic composite NiCr-TiC modified under electron beam irradiation in inert gas plasmas. The models take into account different geometric, concentration and mechanical parameters of ceramic and metallic components. The authors study the contributions of key structural factors in mechanical properties of surface layers and determine the ranges of their variations by providing the optimum balance of strength, strain hardening and fracture toughness. [ABSTRACT FROM AUTHOR]

The paper presents a numerical model of the response for brittle materials to dynamic mechanical loading and implementation of the model within the discrete element method (DEM) by the example of the movable cellular automaton method (MCA). Verification of the model was carried out using the numerical modeling of the uniaxial compression tests of concrete and sandstone samples at various strain rates. It is shown that the developed model is correct and adequately describes the behavior of brittle materials under dynamic loading. [ABSTRACT FROM AUTHOR]

Main attention of the research is focused on the role of vortex-like structures in the velocity fields of the strengthening coating and substrate under contact loading by hard conical indenter. The peculiarities of velocity vortex formation and propagation, as well as its interaction with structural elements are studied. One of possible application of the study is non-destructive technique for detecting nanoscale defects in surface layer of a material using frequency analysis of the friction force. Possibilities of this technique are studied based on 3D simulation. [ABSTRACT FROM AUTHOR]

2D and 3D models of mechanical behavior of brittle porous material under uniaxial compression loading were developed in the framework of the movable cellular automaton method. The considered material was characterized by pore size distribution function having two maxima. On the basis of simulation results the dependence of the strength properties of brittle porous material on its total porosity and partial porosities corresponding to pores with different size was revealed. The change in internal structure of material in a wide range of mentioned parameters was analyzed. The main structural factors influencing compression strength of the material at various combinations of values of porosity parameters were identified. [ABSTRACT FROM AUTHOR]

In the paper we present the results of the theoretical study of some fundamental aspects of mode II crack propagation in conventional sub-Rayleigh regime and transition to intersonic regime. It is shown that development of a sub-Rayleigh shear crack is determined in many respects by elastic vortex traveling ahead of the crack tip at a shear wave velocity. Formation of such a vortex helps to better understand the well-known phenomenon of acceleration of a shear crack towards the longitudinal wave velocity. Simulation results have shown that due to self-similarity of shear crack propagation the conditions of sub-Rayleigh to intersonic transition depend on dimensionless material and crack parameters. Two key dimensionless parameters are proposed. [ABSTRACT FROM AUTHOR]

Movable cellular automaton method was used for simulating uniaxial compression of 3D porous ceramic samples. Pores were considered explicitly by removing randomly selected automata from the original FCC packing. Distribution of pores in space, their size and the total fraction were varied. It is shown that the relation between mechanical properties of the material and its porosity significantly depends on the pore size. Thus, value of the elastic modulus of the samples with large pores is greater than that of the samples with small pores by average value of 3%-16%. Strength value of the samples with large pores is less than that of the samples with small pores by average value of 12% up to the porosity of 0.55, and then becomes to be greater. When the samples contain small and large pores there is a maximum of mechanical properties at ratio of volumes of large and small pores of about 0.75. [ABSTRACT FROM AUTHOR]

Movable cellular automaton method was used for investigating the mechanical behavior of ceramic composites under uniaxial compression. A 2D numerical model of ceramic composites based on oxides of zirconium and aluminum with different structural parameters was developed using the SEM images of micro-sections of a real composite. The influence of such structural parameters as the geometrical dimensions of layers, inclusions, and their spatial distribution in the sample, the volume content of the composite components and their mechanical properties (as well as the amount of zirconium dioxide that underwent the phase transformation) on the fracture, strength, deformation and dissipative properties was investigated. [ABSTRACT FROM AUTHOR]

In the framework of the movable cellular automata method we have developed a plane/2D model of mechanical behavior of brittle porous material under shear loading. The work considers the material characterized by a function of pore size distribution with two maxima. Based on simulation results, the authors proposed the analytical estimation of the dependence of strength and elastic properties of the material on its total porosity and partial porosities that correspond to the pores with different sizes. [ABSTRACT FROM AUTHOR]

In the present paper the multiscale approach to the construction of rheological models of brittle materials with heterogeneous internal structure is implemented within the numerical method of movable cellular automata. An example of application of the implemented approach to determine the mechanical properties (including parameters of the rheological model and strength) of brittle materials with complicated internal structure at both macroscopic and mesoscopic scales is described. The effect of strain rate on brittle materials behavior under uniaxial compression and tension is analyzed. [ABSTRACT FROM AUTHOR]

The work describes the application of the movable cellular automaton method for the simulation of typical situations of nano-scale crack identification in ceramic coatings by the spectral analysis of friction force continuously registered using a small counter-body moving over the coating surface. It is shown that the Fourier spectra of the friction force have peaks that correspond to the distance between the nanocracks oriented perpendicular and at some angle to the tested surface. The obtained results allow to conclude that the appearance of cracks on the Fourier spectra of friction force depends on their orientation. Thus' the distance between cracks' their orientation and sizes can be identified by the method of tribospectroscopy. [ABSTRACT FROM AUTHOR]

A method of numerical simulation of liquid-saturated porous media' that represents a combination of particle method and finite-difference method' namely' the hybrid cellular automaton method was proposed. It allows taking into account inelastic deformations' dilation and fracture of solid skeleton as well as the influence of pore pressure on the stress state of the skeleton and the redistribution of a liquid in filtration volume of porous medium. The method was applied to study the influence of viscous compressible liquid in pores of material on its strength and fracture. It has been shown that the strength of brittle liquid-saturated specimens depends on the material properties and the geometry of porosity' the physical-mechanical properties of the liquid etc. The latter shows the topicality of application of numerical methods to study and predict strength properties of fluid-saturated media under loading. [ABSTRACT FROM AUTHOR]