bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical methods for power equipment tube bundles vibrations studying
Authors: Koretsky S A , Fesenko T N , Dronova E A 
Published: March 2020

Abstract
Calculations of the steam generator model tubes are considered. Dynamics calculation research for those tube bundle model was worked out. Displacements, velocities, accelerations and amplitudes root-mean-square values of tubes vibration acceleration functions were determined as well as their dependences on structural and operational characteristics were investigated. The design parameters include: tube spans length, gape size in tubes nodes coupling and spacer grids, tube radius position.
Combined influence of seasonal processes of permafrost soils on stress and strain state of underground oil pipeline
Authors: Naumov O V , Moskvitin G V 
Published: March 2020

Abstract
The paper simulates the condition of the underground oil trunk pipeline under the combined influence of freezing-thawing processes in permafrost soils. Changes in seasonal temperatures lead to the emergence of processes such as heaving and sinkholes, which affect the spatial position and performance of the pipeline.
The paper presents the calculation of the underground pipeline laying in permafrost with an outer diameter of 520 mm (steel 355 JR), a length of 30 m (depth of 1.5 m), which passes oil temperature 25 °C under pressure of 5 MPa, with the temperature of the outer shell of the pipe 0 °C. Simulation was carried out in SolidWorks using the Simulation package. The stress-strain state and displacements arising from the combined effects of processes in permafrost soils are determined. According to the results of the study, conclusions are drawn about the impact of the combined effects of freezing and thawing processes on the performance of the underground pipeline.
Development of geometrically nonlinear finite element «2-D prismatic joint» using the augmented Lagrangian method
Authors: Nizametdinov F R , Sorokin F D 
Published: March 2020

Abstract
An algorithm for obtaining the stiffness matrix and the vector of elastic forces of a finite element (FE) of kinematic constraints using the example of the geometrically nonlinear element “Two-dimensional prismatic coupling” is proposed in the article. The algorithm is based on the application of the extended method of Lagrange multipliers. The proposed approach is quite general, a wide class of finite elements of kinematic constraints can be developed with it. Also, method for taking into account friction between joined planes for the “Two-dimensional prismatic joint” FE is proposed. Coulomb friction was considered as a model of friction, however, the proposed approach can be extended to other friction models without significant changes. The developed element with friction can be used, for example, for the dynamic skew modelling in rotors that occurs during operation when friction forces are exceeded.
Experimental study of creep and relaxation of steels at the postcritical stage of deformation
Authors: Tretyakov M P , Feklistova E V , Lykova A V 
Published: March 2020

Abstract
The work is aimed at experimental and theoretical study of the regularities and effects of the behaviour of metallic materials at the stage of postcritical deformation, which is of both applied and fundamental interest from the point of view of understanding preceding of the fracture processes and the possibility of predicting the survivability and kinetics of structural failure processes. An experimental assessment was made of the influence of the strain rate in a wide range on the postcritical behaviour of X15CrNi12-2 steel samples at the temperature of 500 °C. Experimental data of rheological processes of the steel at various levels of achieved postcritical deformation was obtained. It was shown that during creep holding at the postcritical stage of deformation, a transition to the final creep stage and subsequent destruction of the samples almost immediately were occurs. An analysis of the experimental dependences obtained during exposition in the relaxation mode demonstrates the independence of the stress level at the end of exposition on the speed of preliminary deformation and, therefore, on the initial value of the stresses, which reached at the beginning of the exposition. The data obtained are necessary to develop models of softening media, taking into account the rheological processes that occur in metallic materials under conditions of postcritical deformation at high temperatures.
Deformation and failure of polymer composite materials under preliminary cyclic and low-velocity impacts
Authors: Wildemann V E , Staroverov O A , Tretyakov M P 
Published: March 2020

Abstract
The paper presents the results of an experimental study of the behavior of samples of polymer composite materials under complex mechanical loads. A technique has been developed for the experimental assessment of changes in the residual strength and stiffness properties of layered composites for various parameters of preliminary cyclic and low-velocity impacts. Corresponding experimental data were obtained for fiberglass samples with various layouts. In accordance with the considered method for analysis of the obtained data, a fatigue sensitivity diagram has been introduced, which contains the characteristic sections of the change in the residual static strength and its threshold values, and is used to study the processes of damage accumulation and fracture of composites at various loading parameters. The results of a study of the effect of preliminary shock tension on the processes of deformation and fracture of fiberglass samples are presented. As a result of the analysis of the influence of a preliminary three-point impact bending on the mechanical characteristics of fiberglass specimens during tension, a threshold value of impact sensitivity was noted, until which a decrease in the residual strength of fiberglass was not observed. A change in the mechanisms of destruction of the samples under static tension with an increase in the energy of preliminary impact is noted.
Study of the lifetime and lubricity of greases for rolling bearings
Authors: Novikov A V , Prozhega M V , Smirnov N I , Smirnov N N , Nazarov A N 
Published: March 2020

Abstract
This article presents a methodology for the study of the relative lifetime of lubricating greases operating in rolling friction. An experimental assembly is described for testing lubricating greases in order to determine the friction coefficient and relative resource. A criterion for assessing the relative resource of lubricating greases has been proposed. The test results of the proposed method were obtained and presented.
Laser surfacing of copper-based alloys on steel
Authors: Prince A N , Biryukov V P , Savin A P , Starostin D A , Klevetov D V , Bazlova T A 
Published: March 2020

Abstract
The paper presents metallographic studies of samples and the results of tribological tests of coatings. It is shown that the friction coefficients of powder coatings based on copper deposited by a laser beam are 2-3 times lower than those of samples made of bronze rods BrAZh 9-4 and brass L63. The influence of transverse beam oscillations on the quality and performance of the surfacing process is investigated. It is shown that at a beam scanning frequency of 217 Hz, the surfacing performance increases by 1.56-1.7 times
Improving measurement precision and informativity under testing antifrictional materials with Timken machine
Authors: Putintsev S V , Chirsky S P , Pilatskaya S S 
Published: March 2020

Abstract
The expediency of modernization of well-known Timken machine is proved. The way of modernizing Timken machine with a two-lever friction pair loading system is given. The measurement precision and test results informativity under antifriction testing of lubricating and engineering materials are improved. The testing of lubricants using the modernized equipment shows high sensitivity to small changes of mechanical losses, as well as extended informativity of short-term test results.
Experimental and computational determination of hardened zones during laser hardening of steels
Authors: Savin A P , Biryukov V P , Panov D V , Prince A N , Petrovsky V N , Ushakov D V 
Published: March 2020

Abstract
Experiments in defocus of beam rectangular-shaped fiber laser in the range of 30-65 mm. using a full factorial experiment, we constructed the surface to depth and width of the zone of hardening through varying the speed of the beam in the range of 15-20 mm/s, power 3-4 kW. Comparative wear tests have shown that laser hardening with a rectangular spot reduces the number of tempering zones and increases the wear resistance of 40Cr steel by 25-35% compared to hardening with a round spot.
Performance study of electric pump unit bearings of spacecraft thermal control systems
Authors: Smirnov N I , Smirnov N N , Prozhega M V , Matveev S A , Shirobokov O V , Gorbunov A V , Zheltyshev O V 
Published: March 2020

Abstract
This paper presents the methodology and test results of rolling bearings of low-flow electric pump units used to ensure circulation of the thermal liquid in the active thermal control system of spacecraft. A multi-position stand has been developed for testing bearings within 40 days in a thermal liquid at a speed of 6000 rpm with the possibility of registering the separator rate speed. As a performance criterion, the clearance in the bearing is used. The conditions of the onset of pitting are investigated.
Study of the wear resistance of alloyed powder-based hybrid materials manufactured using “KARBUL” technology
Authors: Smirnov N I , Prozhega M V , Smirnov N N , Zelenskay M N , Pyatov I S , Shaposhnikova K V , Ladanov S V 
Published: March 2020

Abstract
This research paper presents the results of studies of the tribological properties of materials manufactured using the “KARBUL” technology, modified with powders of various compositions. The tests were carried out according to the “disk-disk” friction pair on a modern friction machine SMT-1. The structure and wear mechanism of materials manufactured using the Karbul technology have been investigated.
Influence of geometric and physical Windbelt system parameters on instability pattern
Authors: Afanaseva A A , Gouskov A M , Ya Panovko G 
Published: March 2020

Abstract
Windbelt system non-linear aeroelastic vibrations are considered. In particular, how the various physical and geometric system parameters (overall dimensions, density of the air and ribbon material, internal damping) affects on the incoming air flow critical velocity value and the system’s supercritical nature of the behaviour.
Some applications of fractional calculus
Authors: Aleroeva H , Aleroev T 
Published: March 2020

Abstract
The present paper investigates a second-order differential equation with a fractional derivative in the lower term, in which the order of the fractional derivative is in the range from zero to two and is not known in advance. This model is used to describe oscillatory processes in a viscous medium. A fundamentally new method has been developed for the approximate solution of the first boundary-value problem for the equation of string vibration taking into account friction in a medium with fractal geometry.
Influence of material damage on the parameters of a nonlinear longitudinal wave which spread in a rod
Authors: Brikkel D M , Erofeev V I , Nikitina E A 
Published: March 2020

Abstract
This paper proposes a new approach to determine new dependences of the nonlinear longitudinal wave parameters on the damage of a material with consideration of physical nonlinearity, as well as the nonlinear relation between deformations and displacements.
Study of rotor dynamics considering a fluid film bearing
Authors: Ivanov I I , Belousov V V , Myasnikov V Y , Serebriakov N N , Shadrin D V 
Published: March 2020

Abstract
Fluid film bearings are widely used in supports of gas turbines, pumps and compressors. They also present in test benches designed for overspeed tests of aircraft engine’s discs. Stiffness and damping of these supporting elements are nonlinear. Moreover fluid film bearing reactions include circulation forces that can bring to well-known types of self-excited vibrations – whirl and whip. Magnitudes of those oscillations are almost not influenced by unbalances and are determined by the system’s properties, in particular – properties of damping and circulation forces. If this type of vibrations does not arise and only forced oscillations present, the corresponding resonance frequencies will depend on unbalances because of fluid film bearing nonlinear stiffness and damping. The listed considerations bring to the necessity of account of nonlinear non-conservative support’s properties in modeling of rotor dynamics. The paper describes the appropriate approach that includes joint use of finite element model of rotor and nonlinear models of supports. The vibrations of rotor with rolling and fluid film bearings in supports are considered as example. Rolling bearings were modeled by nonlinear exponential dependencies of forces on displacements. Those dependencies were computed from the Hertz contact theory. Fluid film bearing was modeled with analytical solution of the Reynolds equation. The problem was solved in nonlinear nonstationary formulation considering mutual influence of rotor displacements and bearing reactions. Results of multiple simulations performed for different values of rotor speed are presented as a frequency response function and a waterfall plot. The results were verified with experimental data.
The analysis of puncheon periodic vibrations of the ultrasonic sewing machines
Authors: Kuznetsov K Y , Markovets A M , Mazin L S , Lugantseva T A 
Published: March 2020

Abstract
The article deals with the research of periodic vibrations of the sewing machine’s puncheon for ultrasonic welding of materials. The dynamic model of the puncheon drive mechanism is analysed, taking into account elastic-dissipative characteristics of springs that are disposed between a puncheon holder and a machine casing, a puncheon holder and an output link of leverage mechanism of the drive mechanism. Welding materials are represented as an elastic-dissipative element and a unilateral constraint element. With the use of the periodized harmonic method, the analytical solution of the nonlinear differential equation of the mathematical model of puncheon vibrations was found. The proposed analytic dependencies can be used for the research of the system’s amplitude-frequency characteristics and the selection of design requirements of the driving mechanism, taking into account the standard conditions of an ultrasonic sewing machine.
Analysis of vibration isolation of a cargo mounted on polyurethane shock absorbers
Authors: Nikitin E A , Belkin A E 
Published: March 2020

Abstract
The mathematical model of vibration isolation system of cargo, mounted in the container on tunnel-type polyurethane shock absorbers, is suggested. This type of shock absorbers allows working modes with finite deformations and has increased damping properties. The model considers nonlinearities of elastic and inelastic characteristics of shock absorbers and asymmetry of load curve. Coefficients of vibration isolation, which correspond to different container’s accelerations, are determined by harmonic and direct linearization methods of ODE of motion.
Simulating oscillations of the system with piecewise-linear characteristics of elastic elements excited by self-synchronizing unbalance vibration exciters
Authors: Shokhin A E , Krestnikovskii K V 
Published: March 2020

Abstract
Oscillations of a system of three solids with piecewise-linear characteristics of the elastic element between the bodies on which unbalanced vibration exciters of limited power are installed are considered in the paper. The modes of oscillations of the system near the second resonant frequency are analyzed. It is shown that intermittent interaction between system elements leads to a change in the dynamic characteristics of the system, including a change in the frequency range of stability of anti-phase synchronization of debalance rotation.
Mathematical modelling on the fracture of a laminar prosthesis basis under natural chewing loads
Authors: Arutyunov S D , Grachev D I , Nikitin A D 
Published: March 2020

Abstract
The modern orthopaedic dentistry offers different constructions for restoration of masticatory efficiency. The choice of construction depends on medical indications with individual patient’s features. Because of that during the dental prosthesis implantation, a doctor faced to the problem of the shape and position parameters choose. Generally, this problem is solved based on empirical guidelines for doctors and personal experience. However, even in the practice of the doctor with a large clinique experience, the prosthesis lifetime does not always reach the guaranteed durability. This paper is focused on the problem of prosthesis base fracture under the natural chewing loads. The mathematical model of prosthesis base interaction with oral tissues is proposed together with 3D finite element simulation of chewing loads. The results of the simulation show a principle distribution of stress in the basis of prosthesis under chewing loads depending on its application. It is outlined an important role of prosthesis base interaction with an anatomic features (torus) of oral cavity. The relation between prosthesis base shape and critical stress state under natural chewing loads is studied.
A method for cantilever dental bridge material selection based upon mastication loads: finite element analysis
Authors: Kharakh Y N , Krupnin A E , Gribov D A , Sorokin F D , Kirakosyan L G , Arutyunov S D 
Published: March 2020

Abstract
A method for cantilever dental bridge material selection based on mastication loads is proposed in the paper. The personalized cantilever dental bridge model was developed. Equivalent von Mises stresses investigated numerically in case of solid food segments mastication that concentrated in pontic and cantilever teeth fissures. It was shown that penetration of solid food (carrot, nut, biscuit) into cantilever tooth fissure may cause values of stresses higher than critical stresses of dental materials used. In contrast, stresses caused by penetration of food into pontic tooth fissure are not so high and proper selection of dental material may provide for required safety factor.
The smart prosthesis as the personal agent in the amputee tactile perception process
Authors: Kovalev N S , Solovyev A A , Sergeev A M 
Published: March 2020

Abstract
This article describes the research phase aimed at the creation the sensorized smart prosthesis system to transradial amputees. The main focus of the article is on obtaining vibration frequency and amplitude that are individuality to user and which arise with the application of Force Sensing Resistors (FSRs). These sensors act as the artificial tactile mechanoreceptors. The micro vibrating motors incorporated in vibro-bracelet placed on the upper arm is used to transmit the sensation of grip force to an amputee. The signal transmission is provided by Bluetooth technology. Arduino was used as the tool for research work.
Hyperbolic and Fibonacci numbers in genetic biomechanics
Authors: Petoukhov S , Petukhova E , Svirin V 
Published: March 2020

Abstract
One-dimensional Fibonacci numbers and their applications are actively used in various fields of mathematics, computer technology and computer science, biology and economics. The article presents the results of the study of additive series of two-dimensional hyperbolic numbers with Fibonacci coordinates. Particular attention is paid to the matrix representation of such hyperbolic Fibonacci numbers. Some applications of new additive sequences in the field of genetic biomechanics are shown, including the laws of morphogenesis of phyllotaxis and the basic psychophysical law of Weber-Fechner. The important role of hyperbolic numbers in the modeling of biological phenomena is noted. The described results lead to new applications of Fibonacci numbers in various fields of science and technology.
The use of nanosized liposomes from vegetable phospholipids in combination with albumine and some polysaccharides as cryoprotective agents in the course of cryopreservation
Authors: Shishova N V , Davydova G A , Kombarova N A , Davydova I B , Poltavtsev A M , Zaraisky E I , Poltavtseva R A 
Published: March 2020

Abstract
It is known that nanosized liposomes from vegetable and animal phospholipids promote survival and functional adequacy of animal cells in the course of cryopreservation. It is also known that albumine and some polysaccharides have membrane-protective properties. In this paper we investigated whether there is a synergism of cryoprotective action between soybean liposomes and macromolecular compounds: albumine, sodium alginate, methylcellulose, carageenan and hyaluronic acid. To determine the cryoprotective effect we carried out cryopreservation of bull semen using a standard procedure in the presence of the substances under investigation. Albumine and sodium alginate demonstrated the most considerable cryoprotective effect in the presence of liposomes. In addition we determined dimensional characteristics of nanoparticles in a liposome suspension without and with sodium alginate and studied the influence of autoclave treatment on the nanoparticle size and cryoprotective effect of the complex. Autoclaving caused enlargement of a small-sized fraction of nanoparticles, supposedly, sodium alginate aggregates. Besides, the autoclaving did not demonstrate any influence on the cryoprotective efficiency of the mixture.
Evaluation of hydrodynamic forces on the impeller of an axial blood pump using computational fluid dynamics
Authors: Skoryukov S V , Kiselev V V , Krupnin A E , Banin E P , Gouskov A M , Sorokin F D 
Published: March 2020

Abstract
The work is aimed at determining the hydrodynamic forces and moments acting on the impeller of the axial blood pump using computational fluid dynamics (CFD). ANSYS CFX software was used for this purpose. The problem solved as steady state with k-ε turbulence. Blood is considered as a Newtonian fluid with constant dynamic viscosity value of 0.00345 Pas for ranges of angular impeller velocities (6000 – 15000 rpm) and volume flow rates (1 - 6 lmin−1). Radial force and torque diagrams were plotted as the result of the numerical experiment.
Comparative analysis of the revision acetabular customized implant position by finite element modeling
Authors: Solovev D O , Maslova I L , Surkova P V , Maslov L B , Zhmaylo M A , Kovalenko A N 
Published: March 2020

Abstract
The article contains a biomechanical assessment of the performance of a customized endoprosthesis of the hip joint. Finite-element models of the hip bone and the implant in the projected and actual positions are prepared. The article provides the results of the static structural analysis for a patient in the two-leg standing position in the post-operative period. The results are compared for various implant positions. As a recommendation, it is proposed to optimize the location and the number of screws for a more uniform stress distribution.