bluuebunny/crossref_metadata_2025_split huggingface dataset:
Theory of composite cylindrical shells under quasistatic vibrations, based on an asymptotic analysis of the general viscoelasticity theory equations
Authors: Dimitrienko Yu I , Gubareva E A , Pichugina A E 
Published: December 2019

Abstract
A theory of thin multilayer anisotropic viscoelastic cylindrical shells with allowance for quasistatic oscillations, based on the application of asymptotic analysis of small geometric parameters to the general three-dimensional equations of the viscoelasticity theory for curvilinear coordinates, is proposed. Recurrent sequences of local problems of the viscoelasticity theory for shells under the quasistatic pressure oscillations are formulated and analytical solutions are obtained. It is shown that with this approach it is possible to obtain expressions for all 6 components of the stress tensor over the thickness of the shell. An example of the calculation of a cylindrical viscoelastic shell with axisymmetric bending with allowance for quasistatic oscillations is considered. The graphs of the dependences of the components of the stress tensor on the local coordinate are given for different angles of layers in the material. An algorithm is proposed for obtaining explicit analytical equations for calculating the distribution of the total stress tensor components over a cylindrical shell under the action of quasistatic oscillations.
Multi-parametric dynamic analysis of lightweight elastic laminates
Authors: Kaplunov J , Prikazchikov D A , Prikazchikova L A , Nikonov A , Savšek T 
Published: December 2019

Abstract
Multi-parametric asymptotic analysis of dynamic phenomena in lightweight three-layered structures is performed. The presence of high contrast in densities of skin and core layers may lead to the small value of the lowest shear thickness resonance frequency, allowing a two-mode long wave low-frequency approximation of the exact dispersion relation. The range of uniform asymptotic validity of the two-mode approximation with respect to relative thickness and density are established. The theoretical predictions are illustrated numerically.
On the Mixed Steklov—Neumann and Steklov-type Biharmonic Problems in Unbounded Domains
Authors: Matevossian Hovik 
Published: December 2019

Abstract
We study the properties of generalized solutions in unbounded domains and the asymptotic behavior of solutions of elliptic boundary value problems at infinity. Moreover, we study the unique solvability of the mixed Steklov–Neumann and Steklov-type biharmonic problems in unbounded domains with a compact and non-compact boundaries (in particular, the exterior of a compact set, half-space, the domain with conical points) under the assumption that generalized solutions of these problems has a bounded Dirichlet (energy) integral with weight |x|
a
. Depending on the value of the parameter a, we obtained uniqueness (non-uniqueness) theorems of these problems or present exact formulas for the dimension of the space of solutions.
To the Modeling of multilayer Thin Prismatic Bodies
Authors: Nikabadze M U , Ulukhanyan A R 
Published: December 2019

Abstract
Proceeding from three-dimensional formulations of initial boundary value problems of the three-dimensional linear micropolar theory of thermoelasticity similar formulations of initial boundary value problems for the theory of multilayer thermoelastic thin bodies are obtained. The initial boundary value problems for thin bodies were also obtained in the moments with respect to systems of orthogonal polynomials. We consider some particular cases of formulations of initial boundary value problems. In particular, the statements of the initial-boundary value problems of the fifth approximation of the micropolar theory of five-layer thin prismatic bodies are considered in more detail.
Homogenization and multicontinuum models for high contrast composites
Authors: Panasenko G P 
Published: December 2019

Abstract
We consider the high contrast periodic composite materials having high ratio ω >>1 of physical constants of the components such as the heat conductivity or Young’s moduli. The ratio of the characteristic microscopic size and the characteristic macroscopic size is a small parameter e. If the component having high constants has the shape of small isolated particles then the homogenized (macroscopic, effective) model demonstrates a loss of the effective wave velocity. If the topology of the component having high constants corresponds to several (at least two) connected periodic sets disconnected one from other and if ε2ω>>1 or ε2ω = const then the macroscopic model is described by a multicontinuum, i.e. several continua in each point.
Requirements for technical support of measurements of local elastic characteristics of CCCM by indentation method
Authors: Andreeva Y D , Magnitskiy I V 
Published: December 2019

Abstract
The paper is devoted to the study of the applicability of the indentation method for determining local properties of the matrix of carbon-carbon composite materials. It is shown that from the point of view of preserving the integrity of the matrix, it is advisable to use an indenter with the maximum possible diameter of spherical blunting. The characteristic values of contact stiffness, which have a significant value, are determined, which imposes restrictions on the components of the power circuit of the indentation device. The laws of changes in the level of stresses in the sample under various conditions, including the friction coefficients in the contact, are obtained. Estimates of the influence of the structural heterogeneity of the material on the measurement results are given, and it has been established that with a rational organization of the experiment, they are negligible.
Advanced repair methods using wear-resistant polymeric composite materials
Authors: Ivanov V A , Tulinov A B 
Published: December 2019

Abstract
The article is devoted to the technology of eliminating defects in equipment used in various industries and utilities. Possible defects are listed, the types of wear and the degree of their influence on the equipment performance are determined. To repair the defects described, it is proposed to use repair composite materials (RCM) made on a polymer base with various fillers, with the advantage given to composites with ceramic fillers as the most wear-resistant and most conducive to eliminating various types of wear in equipment and piping systems. To solve the problems posed, concrete composite materials are available that are available on the domestic market. It also emphasizes the cost-effectiveness of restoration work using RCM.
Dual-curing propargyl/phthalonitrile monomers for composites by vacuum infusion process
Authors: Nechausov S S , Malakho A.P. , Bulgakov B A 
Published: December 2019

Abstract
Four different bifunctional monomers were synthesized: two monomers containing N- propargylamine and phthalonitrile groups and two monomers containing O-propargyl ester and phthalonitrile groups. It was shown that only the latter one can be used to obtain composite materials by vacuum infusion (viscosity 40 mPa*s at 120 °C. The N-propargylamine containing monomers demonstrated high viscosity of the melts and degradation with allene evolution while curing. Carbon fiber reinforced plastics (CFRP) were successfully obtained from 4-[3-(prop-2-yn-I-yloxy)phenoxy]benzene-I,2-dicarbonitrile by a vacuum infusion molding process. Mechanical testing of the composites samples was performed. Influence of end-curing temperature on mechanical properties and morphology of composites was investigated. The curing temperature of 375 °C critically affects the properties of the composite due to the high shrinkage. Composites cured at 375 °C lost 18% of mechanical properties at 300 °C but cured at 330 only 10%. LOI for composites with a matrix of propargyl/phthalonitrile dual-curing polymers was equal to 75, which is higher than most materials obtained from thermosets.
Constitutive relations of the endochronic theory of thermoplasticity for high-temperature composites under plane stress state
Authors: Sarbayev B S 
Published: December 2019

Abstract
A variant of the constitutive relations of the endochronic theory of thermoplasticity for high-temperature composites is proposed. The relations for the plane stress state are considered. Examples of the use of the proposed relations in which the material behavior under complex loading is analyzed are given. The dependence of the elastic modulus of the material on the temperature of pre-heating is shown.
Change in the structure of the aluminium alloy under the action of direct electric current
Authors: Timchenko S L , Zadorozhnyj N A 
Published: December 2019

Abstract
The capabilities of the method for producing cast aluminum alloys, including composite alloys, which include the transmission of direct electric current at the crystallization stage, are shown, and the results are studied for experiments on the crystallization of aluminum alloy (silumin: Si – 10.47 %; Cu – 1.75 %; Fe – <0.2 %; Cr – 0,.02%; Mg – <0.02; Mn – <0.02 %; Ni – 0.08 %) under the action of direct electric current. Comparative study of the structure and porosity of the aluminum alloy, the crystallization of which occurred under the influence of electric current and without current, showed that the electric current leads to a change in the structure of the alloy, reducing porosity, creating a finely differentiated eutectic with a decrease in the dendritic parameter.The mechanism of influence of electric current on the movement of inclusions in the melt is based on the diffusion process. Within the framework of considering the diffusion flux created by the electric field of the current, the speed of the inclusion of crystalline silicon in the melt was calculated in a linear approximation, which shows the possibility of applying this effect in obtaining aluminum matrix composite materials.
Impact toughness of multilayer steel materials at low temperatures
Authors: Vlasova D V , Plokhikh A I 
Published: December 2019

Abstract
The results of a number of studies show that there are ways to drastically change the temperature dependence of the impact strength of structural steels, which at first glance have a paradoxical character. It was established that when the test temperature decreases down to cryogenic temperatures, the work of failure of impact samples cut in certain directions of rolled products does not change, which indicates the absence of a formal viscous-brittle transition threshold and an increase in material reliability at low temperatures. The reason for this phenomenon is the layered structure formed during the hot batch rolling process, due to which complete failure of impact samples with a U-shaped concentrator does not occur.
Study of the process of nitriding in multilayer materials based on steel
Authors: Polikevich K B , Plokhikh A I 
Published: December 2019

Abstract
The paper analyzes the processes of nitriding of multilayer metallic materials at various degrees of their structurization. The dependences of the influence of the thickness of the composite layer and the chemical composition of its materials on the parameters of the diffusion layer during chemical-thermal treatment are presented. It is shown that a decrease in the thickness of the laminar layer leads to an increase in the diffusion layer.
Surface express ultrajet diagnostics of space vehicle materials
Authors: Galinovsky A L , Mugla D R , Golubev E S 
Published: December 2019

Abstract
The article substantiates the possibility of using waterjet hydrophysical diagnostics for the express estimation of features of physical and mechanical properties of structural materials obtained by selective laser sintering. It is shown that, based on the results of ultrasonic diagnostics, functionally necessary information is obtained to improve the quality of implementation of all stages of products’ life cycle in production of which it is promising to use additive technologies. On the example of the constructive element of the Russian Observatory " Millimetron "(Spektr-M project) it is shown that the approaches proposed by the author can be used in the process of technological preparation of rocket’s production and space technology (RST), aircraft building, turbo-power engineering, etc.
Investigation of the scale factor and deformation features during compression of a spatially reinforced carbon composite material
Authors: Ponomarev K A , Magnitskiy I V 
Published: December 2019

Abstract
An experimental analysis of the scale effects of the strength and rigidity of CCCM with a 4-DL reinforcement scheme under compression has been carried out. The influence of the size and shape of the sample on the observed tensile strength and modulus of elasticity of the material is described. The features of nonlinear deformation of the material, the effect of multiple loading are considered. The X-ray computed tomography method analyzed the processes occurring in the structural components of the material.
Development of medical material based on nickel-titanium
Authors: Fakhurtdinov R S , Fedyuk I M , Nasakina E O 
Published: December 2019

Abstract
The paper discusses methods for improving the biomechanical properties of titanium nickelide for its further use as a medical material. The aim of the paper was to study the processes of formation of oxide and nitride surface layers on titanium nickelide by the methods of oxidation and nitration, as well as the effect of these treatments on the mechanical properties and biocompatibility of the alloy.
The use of inflatable structures for the removal of spacecraft from orbit
Authors: Koryanov V V , Toporkov A G , Kazakovtsev V P , Nedogarok A A , Gnezdova E K 
Published: December 2019

Abstract
Every year the concentration of objects of space debris is steadily growing, which significantly complicates the conduct of both modern and future space missions using automatic, and especially manned space vehicles. To date, over 15,000 artificial objects and fragments larger than 5 cm have been recorded in near-Earth space. Therefore, the issues of cleansing outer space from objects of space debris of various sizes are quite relevant. In this paper, are considered questions use inflatable structures for deorbiting spacecraft, in order to avoid the formation of new space debris. At the end of the work, conclusions are drawn about the effectiveness using of such inflatable structures.
Modified Oil Bitumen
Authors: Fedorova L V , Tretyakova Z O , Voronina M V 
Published: December 2019

Abstract
The article describes the modification of petroleum bitumen with elastomers of different chemical nature and molecular weight. The effectiveness and expediency of such a modification is shown.The objects of research in the work were the following brands of oil bitumen: BN-70/30 and BND-90/130. The following modifiers were used: butyl rubber (BK-1675), liquid thiocol - a condensation product of aliphatic dihalo derivatives with sodium polysulfide, rubber crumb.Shown undoubted efficiency and the prospect of improving the technological and operational properties of bitumen systems by modifying the latter with selected polymers. In addition, this modification is economically feasible due to the low cost of the selected modifiers and their presence in the range of enterprises of the domestic chemical industry.
Influence of aggressive environment on basalt fiber based microplastics
Authors: Korokhin R A , Solodilov V I , Kireinov A V , Orlov M A 
Published: December 2019

Abstract
Physical and mechanical properties of basalt fibers and microplastics based on them have been investigated. Influence of various environments such as distilled and sea water, alkaline solutions, UV-radiation, on microplastics’ characteristics have been studied. Alkaline solutions of high concentration are shown to affect the most the characteristics of studied materials.
Newer approaches to the creation of the thermostable space platforms for the Earth remote sounding
Authors: Gorodetsky M A , Mikhaylovsky K V , Reznik S V 
Published: December 2019

Abstract
A method for the integrated analysis and the determination of the composite construction parameters of a platform of the Earth remote sounding spacecraft, is proposed. The conditions of thermal load for a flight along a sun-synchronous orbit were analysed. The mathematical simulation of the operating conditions ensuring the effective operation of such satellites was performed. The method was tested with account of the input parameters of the «BelKA» satellite orbit. This method will be useful when selecting a working orbit for such satellites at the stage of technical proposals, since it includes determination of their orbital characteristics, as well as the heat flows onto the elements of their construction. The results of simulation of thermal regime of the composite structure options are presented.
Metallic coating technologies for carbon fabrics and methods for assessing their quality
Authors: Nelyub V A 
Published: December 2019

Abstract
The results of experimental analyses of the properties of carbon tapes (and filaments) after the application of metal coatings on them are presented. Various methods have been investigated for pre-cleaning the surface of carbon tapes and fabrics before applying a metallic coating thereon. A magnetron sputtering method was used to apply the metallic coating. An algorithm has been developed that allows determining the method of pre-cleaning carbon tape before its metallization. An adhesive test method was used as a criterion, allowing to determine the adhesion strength of the metallic coating to the carbon tape. An algorithm has been developed that allows determining the modes of applying metallic coatings on a carbon tape. Modes of applying metallic coatings on carbon tapes have been developed.
About the mechanisms of fibre reinforced plastic behaviour under cycling loading
Authors: Paimushin V N , Kayumov R A , Kholmogorov S A 
Published: December 2019

Abstract
In order to study the peculiarities of the behavior of fiber reinforced plastics under cyclic loading, tests of specimens made of ELUR-P carbon tape and cold curing binder XT-118 with a stacking sequence 2 [+45°/−45°]2s
(s - the number of laminas) for cyclic tension were carried out. It is established that stabilization of the secant modulus of elasticity is observed as the number of cycles increases. The experimental data were compared with the results of numerical modeling of the deformation processes under study. Based on numerical calculations and analytic solutions found, for a number of types of loads and creep kernels, the value of the secant modulus of elasticity does not depend on the load amplitudes, when using relations with the Abel creep kernel, the ratio of viscous parts of strain shifted by values, does not depend on the period of cyclic load, the amplitude of the load and the parameter that determines the degree of viscosity of the material, but depends only on the parameter that determines the degree of attenuation of the creeping process. By using the method of decomposing the load in a series of trigonometric functions with the same cyclic periods, it is shown that the effect is manifested in the general case of cyclic loading using relations with the Abel creep kernel. There is established the independence of secant and tangential moduli of elasticity from the absolute values of maximum and minimum stresses for any kinds of loads and creep kernels using the linear theory of hereditarily elastic body. A method has been developed for identifying creep kernel parameters, relations for viscoplastic and elastic strain based on the analysis of experimental data on cyclic loading. For the separation of hereditarily elastic and viscoplastic strain, the hypothesis was introduced that their rates at large times are very different. This made it possible, on the basis of theoretical results obtained for the Abel kernel, to obtain ratios from which, independently of other mechanical characteristics, one can find the attenuation parameter from the strain values, measured in the experiment in times shifted by an integer number of periods. The method is applied to processing the data of real experiments conducted by the authors.
Numerical calculation of the stress-strain state of piezoelectric layered polymer composite materials equipped with a control piezoactuator
Authors: Anoshkin A N , Pisarev P V , Pan’kov A A , Ashikhmin V A 
Published: December 2019

Abstract
A mathematical model is formulated for calculating the stress-strain state (SSS) of piezo-electric layered polymer composite materials (PCM) equipped with a control piezoactuator. The model implements the principle of thermo-piezoelectric analogy, which allows to move from the coupled boundary value problem ofelectroelasticityto the boundary value problem of thermoelasticity. A comparison of the deformation fields for model layered samples from PCM with a different arrangement of piezoactuatorswas carried out. Verification of the developed mathematical models was carried out. The main patterns and mechanisms are revealedfor controlling the geometry of a layered PCM using embedded piezo-actuators.
Creation and analysis of hybrid nanocomposites based on dioxidine and nanoparticles of bioactive metals embedded in cryostructurated gelatin matrices
Authors: Nuzhdina A V , Shabatina T I , Vernaya O I , Shabatin V P 
Published: December 2019

AbstractThis paper is devoted to the creation of hybrid nanocomposites based on the antibacterial drug dioxidine and bioactive metals - silver and copper. The obtained materials were analyzed using the methods of NMR, UV and IR spectroscopy, low-temperature adsorption of argon, SEM and TEM. It is shown that they are silver nanoparticles with a size of 2-30 nm or copper nanoparticles with a size of 10-40 nm, incorporated into dioxidine particles with a size of 50-350 nm. The obtained drug nanocomposites were embedded into wide-porous biopolymer cryostructurated gelatin-based matrices. The possibility of the release of drug components from a biopolymer carrier and manifestation of its antibacterial activity has been shown. At the same time, hybrid nanocomposites based on metals and antibacterial drugs showed increased activity to suppress the growth of microbial cells ofEscherichia coli 52, Staphylococcus aureus 144, Mycobacterium cyaneum 98,then their components separately.
The effect of curing temperature on phase separation, morphology, fracture toughness and impact resistance of epoxy-polysulfone blends and fiber reinforced plastics based on them
Authors: Solodilov V I , Shapagin A V , Korokhin R A , Gorbatkina Yu A 
Published: December 2019

Abstract
The influence of the curing temperature of epoxy - polysulfone compositions on crack and impact resistance of matrices and unidirectional reinforced plastics was studied. It was shown that the structure of cured material depends on the content of PSK-1 and the curing temperature. Stable effect of increasing fracture toughness, as a rule, is observed for matrices with an extended structure of thermoplastic, which is typical for the phase structures of the type "interpenetrating phases". Energy of destruction of fiber reinforced plastics is determined by the fracture toughness of the matrix and its resistance to impact, which depend on the type of structure formed in the curing process.
Increase of composite structures strength by carbon fiber surface modification with spray deposited carbon nanotubes
Authors: Levin D D , Romashkin A V , Polikarpov Yu A , Struchkov N S , Kireynov A V , Komarov I A 
Published: December 2019

Abstract
The possibility of carbon fiber and the polymer matrix interfacial interface improvement by modification carbon fiber surface with functionalized carbon nanotubes. Nanotubes were deposited to carbon fiber surface by aerosol spray deposition, to increase the tensile strength of composite structures. The relationship between the tensile strength of the composite structure with the epoxy matrix and the uniformity of carbon nanotube coating was investigated.