Molecular dynamic modelling of seed cracks evolution in iron bicrystals with inclined grain boundaries under uniaxial expansion was carried out. The process of seed crack evolution can be divided into four stages. At the first stage, in the interval of elastic deformations, the seed crack is stationary, and the stresses increase linearly, reaching a maximum value of ~7.0 GPa. At the same time, the atomic volume and stresses at the crack tip before its opening grow significantly faster than the average for the sample. At the second stage, the crack begins to spread into the grain volume. The process of crack propagation leads to an abrupt stress release due to relaxation processes in the areas adjacent to the crack banks and the emission of defects from the crack tip. After reaching the grain boundary, the crack stops and blunts. At the third stage, the crack remains in the grain boundary, and the sample stresses experience significant oscillations, which is caused by the emission of various defects both from the grain boundary and from other interfaces. The emission of defects from the crack tip can cause local migration of the grain boundary, which is formation of a bend on the initially flat surface of the grain boundary. When defects cease to be emitted from the crack tip, the voltage and atomic volume in this region increase rapidly. At the fourth stage, the crack begins to spread into the second grain. It was found that a boundary with a large grain misorientation angle is a more effective barrier restraining crack propagation. Initiation of the seed crack propagation in material is always preceded by an abrupt increase in atomic volume and stresses at the crack tip.

The behavior of hydrogen molecules in carbon nanopores of different shapes (slit-shaped, cylindrical, and spherical) is investigated using the molecular dynamics method. It is shown that an adsorbed molecular layer with increased density is formed near the nanopore walls, and dynamic equilibrium is established between this layer and the gas in the central region of the nanopore. The distribution of the density of gas molecules over the cross section is found to depend on the size and wall curvature of nanopores: with a reduction in the nanopore size, the density of the adsorbate increases more rapidly in spherical nanopores, whose walls are characterized by greater mean curvature.

Peculiarities of metal wire explosion by high voltage loading are investigated. Embedded atom method is employed to calculate atomic interaction. In this work, cylindrical specimens of polycrystalline copper are examined. High-rate heating of specimens induced by high-density electric current is simulated by scaling the velocities of atoms. It is demonstrated that simulated specimen destruction caused by high-rate heating leads to formation of vapor phase and clusters of various sizes. Simulated system behavior during explosion is determined by processes of destruction and cluster agglomeration, surface atom evaporation, cluster collision, and atom deposition on clusters free surfaces. Influence of the grain boundary region on processes of destruction and formation of clusters with internal block structures is revealed. It is proved to be the case of nonuniform distribution of electric current density (temperature) on the stage of high-rate heating.

The nucleation and development of plastic deformation in a crystalline grain of titanium (Ti) during uniaxial tension has been studied by molecular dynamics (MD) simulations with the interatomic interaction described using the embedded atom method. Specific features of the generation of local structural rearrangements in the grain at various straining rates are revealed. It is established that there is a threshold deformation level at which local structural rearrangements begin to nucleate in the crystal, which is accompanied by a jumplike decrease in the potential energy. Because of the inertial character of the accommodation processes, this threshold value increases with the loading velocity.

The structure of dusty plasma clusters in the ground state for various configurations of the confining field has been simulated using the molecular dynamics method with the interaction between spherical particles of dusty plasma described in terms of an isotropic Yukawa pair potential. Depending on the degree of the confining field anisotropy (i.e., a difference between forces in the vertical and horizontal directions), conditions for which a three-dimensional (3D) structure in the ground state ( isotropic confining field) transforms into a 2D structure are determined. The shape, dimensions, and structure of dusty plasma clusters have been studied in systems with various numbers of particles and degrees of anisotropy of the confining field.

The behavior of nanodimensional bilayer structures (plates) of finite length consisting of nanometer-thick crystalline Ni and Cu films has been studied by means of molecular dynamics simulation. The inter-atomic interactions were described within the framework of the embedded atom method. It is shown that, in the absence of an external action, the nanostructures perform mechanical oscillations with the amplitude and frequency determined by the length and thickness of the plate. The dependence of the parameters of oscillations of the nanodimensional structures on their dimensions is established. The results can be used in designing components of nanodevices for various applications.

The behavior of Coulomb balls of charged spherical dust particles under conditions of pulsed uniform loading of their outermost shells at various intensities has been studied by molecular dynamics modeling. If the intensity of the external load is below a certain threshold, the shell structure of the Coulomb ball is retained and the oscillations of outer shells are characterized by gradually decaying beats. As the intensity of the uniform loading increases, the shell structure exhibits smearing and, under the action of a threshold load, the system passes to a fluid-like state. The oscillation frequency of the outermost shell is independent of the intensity of uniform loading. Calculations show that, as the number of dust particles in a Coulomb ball increases, this frequency tends to a certain limiting value.

A binary mixture of dust particles in plasma occurring in an external electrostatic spherical confinement field has been numerically simulated. Calculations have been performed within the framework of the molecular dynamics method, with the interparticle forces described in terms of an isotropic Yukawa pair potential. It is shown that the particles form a shell structure, each particular shell consisting of particles of the same kind. The structural properties of such a binary mixture of particles and the specific features of their segregation under the conditions of recent experiments on the formation of Coulomb balls have been studied.

A molecular-dynamic study of nucleation of structural defects in materials with an initially perfect crystal lattice by thermal fluctuations under high strain rates is performed. It is shown that thermal fluctuations can generate structural defects. There exists some threshold value of strain at which abrupt growth of regions with local structural changes is observed.