The main problem in manufacturing friction materials is still a lack of sufficient information about the processes occurring in the surface layers of contacting bodies. This is due to the complexity of the processes which are taking place during friction and wear and by interdependency of mechanisms at various scale levels. This also may partly explain the complexity of structure of the composite materials which are used as brake pads, because a wide range of requirements have to be satisfied for modern braking systems. How variations of material composition affect the frictional characteristics of the friction pair is still an area of intense research. The present study used a computational method of the discrete approach — a method of movable cellular automata — to investigate the interaction of nano-scale features which are typical for the pad-disc-interface during automotive braking. The results can be useful for understanding the features of interaction of materials and control their performance properties.

In the present paper simple analytical expressions connecting bulk moduli for fullerenes 𝐶₂₀ and 𝐶₆₀ with stiffness of interatomic bond and geometrical characteristics of the fullerenes are derived. Ambiguities related to definition of the bulk modulus are discussed. Nonlinear volumetrical deformation of the fullerenes is considered. Pressure-volume dependence for the fullerenes under volumetrical compression are derived. Simple analytical model for volumetrical vibrations of the fullerenes is proposed. The expression connecting frequencies of volumetrical vibrations for fullerenes 𝐶₂₀ and 𝐶₆₀ with parameters of interatomic interactions are obtained.

Polymer/silicate nanocomposites mechanical behaviour under finite deformation is investigated at structural level. Outcomes of computer simulation are presented. Nano-filler particles are modeled represented as sheaves from the several parallel ultrathin silicate plates parted by beds of polymer (tactoids), a matrix - as a nonlinear-elastic or elastoplastic material.

The stress-strain state round separate inclusion in dependence on its orientation to a exterior load direction and properties of a matrix is researched. The problem of the macro-homogeneous elongation of a periodic cell in the form of the rectangular field with a tactoid at centre has been solved for this purpose. Conditions at which a filler particle losses of a bending stability happens in the course of macroelongation of material are defined.

The estimate of nanocomposite macro mechanical behaviour depending on properties of a matrix, filler concentration and orientation of corpuscles is spent on the basis of the gained solutions. Appropriate dependencies between macro and micro-structural parameters associations are built.

Molecular dynamics simulation of nanostructure behavior under impulse heating is carried out. These structures are formed by self-rolling of nano-thickness bilayer crystal films. The interatomic interactions are described by potentials obtained by the embedded atom method. The calculation data are shown that simulated nanostructures can transform the supplied thermal energy into the mechanical oscillations of its free edges. The influence of heating rate and its duration, medium viscosity properties on kinematical characteristics of simulated nanostructures is investigated. The influence of mass and size of oscillating free edges of nanostructures on their behavior under heating is studied. The efficiency estimation of thermal energy transformation, supplied to nanostructures, into mechanical oscillations of their free edges versus nanostructure configuration, chemical composition and rate of impulse heating is carried out. The atomic mechanisms responsible for the peculiarities of local atomic structure transformations in bilayer nanofilm under its detaching from the substrate as well as mechanism of thermal energy conversion into mechanical one by nanostructures are investigated.

Stability of 2D triangular lattice under finite biaxial strain is investigated. In this work only diagonal strain tensor is regarded. The lattice is considered infinite and consisting of particles which interact by pair force central potential. Dynamic stability criterion is used: frequency of elastic waves is required to be real for any real wave vector. Two stability regions corresponding to horizontal and vertical orientations of the lattice are obtained. It means that a structural transition, which is equal to the change of lattice orientation, is possible. The regions’ boundaries are explained: wave equation coefficients change their signs at the border, as well as Young modulae and shear modulae. The results are proved by direct numerical simulation.

We present the results for the elastic properties of a single layered carbon monofluoride or fluorographen (FG). The calculations were performed by molecular dynamics (MD) simulation using a force field with both bonded and non-bonded interatomic contributions, and the periodic boundary conditions in two dimensions, representing an infinite “nanoplate”. Simulations were fulfilled both for three basic conformations of FG [1] and for the FG with number counts of structural defects. The elastic modulus was calculated from the curves of force versus displacement obtained at slow rates of deformation. Bending stiffness was estimated independently from the nonlinear deformation under compression. The atomistic results are explained in terms of a continuum model for the thin plates.

The copper nano-sized particles collision under various loading condition was studied in the paper. The special attention was paid to changes in structure of the particles. The numerical investigations were performed by molecular dynamics method. The inter-atomic interaction was described within the embedded atom method. The initial particles were of ideal crystal structure, spherical shape, radius of 6–15 nm. The velocity of collision was varied from 200 up to 1000m/s, rotation of the particles with the speed up to 1.5⋅10¹³ s⁻¹ was applied in some calculations. It was shown that specific changes in initial ideal crystal structure of the particles took place under interaction, and the shape of the final particle was not symmetric one. The changes in potential energy of the particles, structural transformation from one type of the crystal lattice to another one as well as quasi-amorphous regions formation were studied in detail.

The main result of this work is that the small-amplitude long wavelength bending oscillations of carbon nanotubes (CNT) become localized ones if the intensity of initial excitation exceeds some threshold which depends on the CNT length. This localization results from the intensive resonant interaction of zone-boundary and nearest modes in the weakly nonlinear regime that leads to loss of stability of the zone-boundary mode as to the first step. The further development of resonant interaction leads to effective confinement of energy in the part of the system only. We study this process in the terms of Limiting Phase Trajectories and demonstrate the usefulness of transition from “modal” to “effective particles” representation for description of the system under consideration. We also show that the similar tendency to localization of oscillation is the common property of the systems, the eigenvalue spectra of which are non-equidistant ones near their edges.

We study an opportunity to increase elastic moduli of a nanocomposite due to stress-induced phase transformations which lead to the formation of intermediate new phase layers around nanoparticles. These layers enlarge the effective size of the particles which from now become inclusions made up of kernels (the initial nanoparticles) enclosed by new phase layers shells. Increasing the volume fraction of the inclusions can change the effective elastic moduli of the composite much more than one could expect in a case of the composite with a small volume fraction of initial nanoparticles. As an example we consider an isotropic composite with spherical particles under hydrostatic loading. We begin with considering the new phase formation around an isolated inclusion including the interface stability analysis. We show that stable two-phase states are impossible if both elastic moduli of the matrix increase due to phase transition and possible if the bulk modulus increases and the shear module decreases. Then, basing on a self-consistent approach, we describe the new phase formation around spatially distributed particles and study how external strains effects the new phase areas growth. Finally we demonstrate that the new phase layers formation can lead to increasing the effective bulk modulus of the composite.

The modelling of the shear strength of nanotubes based nanocomposites is considered. To model the shear strength of nanocomposites it is assumed that the zone of the adhesive interaction between nanotubes and a polymeric matrix is a thin interface layer which has resistance only in the relation to action of shear stresses and has the given curve of deformation. The stress state of nanotubes and a polymeric matrix is determined in the assumption, that the nanotube is a cylindrical fibril with the straight axis, embedded in a infinite polymeric matrix and the displacement along the axis of the nanotube under the action of the external loading along this direction are much more than others components of the nanotube and matrix displacements. The analytical solutions for the axial displacement and normal stress in the nanotubes and the shear stresses in the interface layer for a case of the bilinear deformation curve of an intermediate layer with elastic and hardening or softening branches are obtained.

In using the method of molecular dynamics simulation of contact interaction between the copper crystallite and the various pure metals under shear loading was carried out. Shown that the structure of the boundary layer obtained during the shear deformation is determined by the loading conditions and materials of contact pair. In particular, in the interaction of copper with aluminum, soft aluminum material begins to be introduced into the lattice of copper, and in the interaction of copper with iron, this process is not observed. The effect of loading conditions and mode of heat transfer was studied. The research results can be useful for controlling strength properties of interfacial layer coated material, as well as to control the properties of the surface layer in contact problems.