107 Works

Modeling of elastoplastic steel deformation in two-link broken trajectories and delaying of vector and scalar material properties

V.G. Zubchaninov, E.G. Alekseeva, A.A. Alekseev & V.I. Gultiaev
On the basis of a mathematical model of A. A. Il'yushin's theory of elastoplastic processes, numeric calculations are given for programs of experiments in the form of two-linkbroken strain trajectory. The results of the numeric simulation are compared with the experimental data obtained by authors on the automated test-machine SN-EVM. Delaying of vector and scalar properties is investigated. The instability of magnitude of the trace of delay as a characteristic of the material is shown.

Rotary actuator control based on tensile force elements made of shape memory Cu-Al-Ni crystals when operated in a cyclic mode

A.I. Priadko, S.A. Pulnev, O.O. Kovalev & I.A. Ilin
An actuator design and a function scheme are developed. A control algorithm of a cyclic actuator is considered. We provide experimental results on the control algorithm and the actuator. The actuator operating range is 60°. The actuator sped is ~ 1 degree/second. The actuator operating is stable in any rotation angle in operating range.

Electron tunneling to the surface states at photocatalysis

T.N. Sidorova & Alexander L. Danilyuk
Simulation of tunneling electrons excited by the sunlight in TiO2 to surface states is performed for TiO2/Si nanostructure. The tunneling transmission coefficient of the surface states created by organic compounds was calculated by phase function method. Dependence of the transmission coefficient of tunneling electrons on potential barrier parameters is explained by interference of transmitted and reflected waves. doi: 10.18720/MPM.4112019_3

BULK GREEN'S FUNCTIONS IN ONE-DIMENSIONAL UNSTEADY PROBLEMS OF ELASTIC DIFFUSION

L.A. Igumnov, D.V. Tarlakovskii & A.V. Zemskov
We consider a one-dimensional unsteady problem of elasticity with diffusion and preset unsteady volumetric disturbances. The mathematical model is based on a local equilibrium model of elastic diffusion. The solution is sought in integral form. The bulk Green's functions are found via Laplace transform and Fourier transform for unbounded medium, sine and cosine transform for semi-bounded medium, Fourier's series for bounded medium.

The influence of an adhesive layer on the interaction between a piezo-actuator and an elastic 3D-layer and on the excited wave fields

E.V. Kirillova, W. Seemann & M.S. Shevtsova
Piezoceramic transducers are extensively used in nondestructive testing (NDT), structural health monitoring (SHM) and condition monitoring (CM) of various mechanical systems including wind turbines, aircraft structures, bridges and pipeline systems. Piezoelectric transducers are surface bonded on the host structure and are excited to produce structural responses. This article highlights the effect of the adhesive layer between the studied structure and the transducer on the contact characteristics and the structural wave fields. The research also focuses...

On some features of identification of inhomogeneous prestressed state of thermoelastic hollow cylinder with coating

A.O. Vatulyan & S.A. Nesterov
An inverse thermoelasticity problem of identification of inhomogeneous prestressed state of an infinitely long hollow cylinder with a coating is formulated. The characteristics of cylinder's material are described by piecewise continuous functions. A direct thermoelasticity problem is solved on the basis of the shooting method and inversion of solutions based on the Durbin method after applying the Laplace transform. The nonlinear inverse problem is solved by constructing an iterative process, at each stage of which...

APPLIED THEORY FOR ELECTRO-ELASTIC PLATES WITH NON-HOMOGENEOUS POLARIZATION

A.N. Soloviev, V.A. Chebanenko, P.A. Oganesyan, Shih-Fong Chao & Y.-M. Liu
Non-uniformly polarized piezoceramic materials can be used in effective energy harvesting devices. Axisymmetric and plane models of electric elastic bodies were studied using applied theory and finite element method (FEM). Applied theory for devices made of parts with longitudinal and transverse polarization was developed. It was based on bending of electric elastic plates models. Numerical experiments for FEM models were performed in ACELAN package. Applied theory of second order vibrations was introduced.

Effect of cooling rate on the crystallization of aluminum alloys under pressure

Maksim S. Denisov
The influence of pressure on the compressibility of liquid metal and the release of latent crystallization heat is studied. It is found that the pressure application combined with the cooling rate creates metastable structures. It can be used for improvement the properties of metals and alloys. doi: 10.18720/MPM.4112019_14

Effect of anodic voltage on parameters of porous alumina formed in sulfuric acid electrolytes

X. Huang, W. Su, L. Sun, J. Liu, D.A. Sasinovich, O.V. Kupreeva, D.A. Tsirkunov, G.G. Rabatuev & S.K. Lazarouk
Local porous aluminum anodizing with a photolithography mask has been carried out at anodic voltages varying from 15 to 200 V in sulfuric acid electrolytes. Record anodic voltages at room temperature have been achieved leading to new parameters of porous alumina such as interpore distance up to 320 nm, forming cell factor up to 1.2 nm/V, thickness expansion factor up to 3.5, porosity up to 1%, sulfur concentration up to 7.7 at.%. A central angle...

Added mass study of plane structures at their various motions

Daniil Morozov, Dmitry Indeitsev & Alexander Michailov
Using FE analysis, this work fully devoted to added masses determination of the plate in infinite liquid in the case of different movements. Various forms and sizes of the plate are considered. The problem consists of two parts: first is studying of the plate motion in liquid as rigid; second is studying of the plate vibrations in its own modes, fixed with a hard screen and contacting with liquid by one side. The condition observance...

BORON AND NITROGEN DOPANT ATOMS PRECISE TUNING (INCREMENT AND REDUCTION) OF CHARGE-TRANSFER RATES IN HYDROGENATED GRAPHENE

G.K. Sunnardianto, F. Triawan, A.M. Aamer, S. Hastuty, A.B.D. Nandiyanto & A.G. Abdullah
Graphene is a new remarkable material for diverse applications, especially when grapheme is interacted with hydrogen. The charge-transfer rates (CTR) from hydrogen to graphene is substantial to determine the electronic properties. A new approach to increase and decreases the charge-transfer from hydrogen to graphene is proposed. By using density functional theory calculation method, the effect of B and N doping on the CTR of hydrogenated graphene is investigated. The results found that both of dopants...

Finite element modeling and investigation of elastic homogeneous and heterogeneous materials

V.L. Leontiev & I.V. Efremenkov
A novel finite element (FE) connected with orthogonal finite functions (OFF) was developed for ANSYS software and was tested. The FE is proposed for modeling and investigation of stress-strain states of homogeneous and heterogeneous elastic materials. The efficiency of the developed FE is demonstrated using the examples of plane problems of elasticity. The accuracy of this FE was found to be higher than that of the classical FE of ANSYS. Moreover, the developed FE was...

Effect of warm rolling on microstructure, porosity, and hardness of a spray-formed LM25 aluminum alloy

Bandi Venkata Ramana Reddy, S.R. Maity & K.M. Pandey
The LM25 aluminum alloy was obtained using the spray deposition method at an optimum pressure of approximately 10 bar, a deposition distance of approximately 41 cm. and an inclination angle of 0º. The central portion of the spray deposit was warm rolled to obtain various thickness reductions, i.e., 0%, 20%, 40%, 60%, and 80% at 100ºC; it was found that the number of pores decreased as the thickness reduction increased. It was observed that the...

Use of X-ray analysis for conducting input and process control of electronics materials

Aleksandra N. Matvienko, Sergey P. Teslenko & Svetlana V. Shtelmah
The paper presents examples of using X-ray diffraction and X-ray phase analysis for monitoring and researching materials for electronic equipment. doi: 10.18720/MPM.4112019_13

Skew Brownian motion with dry friction: Pugachev-Sveshnikov approach

Sergey Berezin & Oleg Zayats
The Caughey-Dieness process, also known as the Brownian motion with two valued drift, is used in theoretical physics as an advanced model of the Brownian particle velocity if the resistant force is assumed to be dry friction. This process also appears in many other fields such as applied physics, mechanics, astrophysics, and pure mathematics. In the present paper we are concerned with a more general process, skew Brownian motion with dry friction. The probability distribution...

Sumanene and fullerene C60

Alexander I. Melker, Maria A. Krupina & Ruslan M. Zarafutdinov
In this contribution we have considered fusion reaction of carbon clusters obtained from the natural blocks of sumanene. We obtained four natural isomers of fullerene C60. Together with the fifth natural isomer found elsewhere through the use of the Endo-Kroto mechanism (dimer embedding model), now we have the structure of all the experimentally observed isomers of fullerene C60. One isomer is a perfect, the other are imperfect and differ in the number of pairs of...

Tetrahedral miniand midi-fullerenes

Alexander I. Melker, Sergey A. Starovoitov & Ruslan M. Zarafutdinov
We have considered possible ways of forming the simplest tetrahedral fullerenes, namely elementary tetrahedron C4, truncated tetrahedron C12, half-truncated cube C16, fullerenes C28 and C36. By analogy with ionic crystals, we introduced "mathematical" compounds, which form a topological cube of two tetrahedra inserted into each other, and construct graphs for them. Combined with the graph analysis, this approach allows obtain a clear knowledge of the tetrahedral fullerene structure. We extended our model to other tetrahedral...

Dynamics of a frictional system, accounting for hereditary-type friction and the mobility of the vibration limiter

Leonid A. Igumnov, Vladimir S. Metrikin & Mikhail V. Grigoryev
Dynamics of a frictional system consisting of a rough body situated on a rough belt moving at a constant velocity is studied. The vibrations are limited by an elastic obstacle. The Coulomb-Hammonton dry friction characteristic is chosen, according to the hypothesis of Ishlinskiy and Kragelskiy, in the form of hereditary-type friction, where the coefficient of friction of relative rest (CFRR) is a monotone non-decreasing continuous functionof the time of relative rest at the previous analogous...

A numerical study of ballistic behaviour of ceramic metallic bi-layer armor under impact load

M.K. Khan, M.A. Iqbal, V. Bratov, N.K. Gupta & N.F. Morozov
A 3D finite element model has been developed for studying the ballistic behaviour of bi-layer ceramic-metal target plates under the impact loads induced by the projectiles of different diameter to length ratios. The bi-layer target constituted of alumina 95, as front layer, backed by aluminium alloy 2024-T3 layer, has been impacted by steel 4340 blunt and ogival nosed projectiles of diameter to length ratios, 0.5 and 1.1. The constitutive behaviour of ceramic was modelled using...

Polycrystalline films of phosphors Cd(1-x-y-z) (CuyAgz) ZnxS on the silicon substrate with the silicon carbide buffer layer: structure and properties

N.M. Sergeeva, S.P. Bogdanov & A.V. Redkov
Polycrystalline phosphor film Cd(1-x-y-z) (CuyAgz) ZnxS was grown on the surface of the Si/nano-SiC heterostructure obtained by the unique method of substitution of atoms. The structural, phonon (vibrational) properties of the film, as well as its morphology were studied. X-ray phase analysis (XRD) showed that the phase composition is represented by a matrix of solid solution of cubic syngony and impurity phases formed during precipitation: sodium sulfate (Na2SO4) of orthorhombic syngony and sodium cadmium sulfide...

On a configurational force driving surface growth of solids

A.B. Freidin & Y.O. Izmaylova
Surface growth of solids includes a wide variety of processes starting from additive manufacturing technologies and ending with plenty of biological problems. Model of surface growth based on the expression of the configurational force, derived from fundamental laws and entropy inequality, is offered in the present paper. A new expression for the configurational force called surface growth force, which controls growth and resorption, is used. Analysis of the applicability of the developed model was carried...

Nonlinear dynamics of serrated deformation of metals at low temperatures

G.F. Sarafanov & V.N. Perevezentsev
The mode of the serrated deformation is investigated mathematically in framework of the thermoactivation model of unstable plastic deformation in metals at low temperatures. The obtained solutions in the framework of known models, however, do not fully correspond to experimental situation, as the stress oscillations in reality are usually irregular and inhomogeneous. By this reason, additionally, the elastic correlations of neighboring deformation zones were taken into account in the model. Numerical analysis model showed that...

Asymptotics of a thermal wave in one-dimensional harmonic crystal

A.M. Krivtsov, E.A. Podolskaya & V.Yu. Shubina
An asymptotic representation is obtained at large times for the thermal wavefront propagating in a one-dimensional harmonic crystal. The propagation of thermal waves from a localized thermal perturbation and the transition zone between regions with different temperatures is considered. An explicit solution is given for a number of the simplest forms of the initial temperature distribution. It is shown that during the wave evolution, the wavefront smoothes, e.g., for a power-law dependence its degree increases...

Shear anisotropy in Si-Cu interfaces on the atomic scale

D. Johansson, P. Hansson, A. Ahadi & S. Melin
Three dimensional molecular dynamics (MD) is used to model the mechanical response at the interface between a thin Cu coating resting on a base of Si. The copper coating is subjected to a displacement controlled shear load and the atom movements at the Si-Cu interface are monitored to investigate the effects of crystallographic anisotropy. The two crystals have the same crystallographic orientation, and two different interface normal directions are considered. The shear load is applied...

Construction of stress-strain curves for aviation materials database formation

B.E. Vasilyev, M.E. Volkov, Е.N. Bredihina & I.I. Pleshcheev
This paper discusses specific aspects of elasto-plastic behavior of various materials. It was shown, that during tensile test additional measurements are necessary for constructing stress-strain diagram. Concept of minimal stress-strain curve is presented. Issues and difficulties arising in obtaining and minimal stress-strain curve are discussed. Methods of obtaining statistically valid engineering and true stress-strain curves are introduced.

Registration Year

  • 2019
    107

Resource Types

  • Text
    107

Affiliations

  • Peter the Great St. Petersburg Polytechnic University
    10
  • N. I. Lobachevsky State University of Nizhny Novgorod
    8
  • Institute of Problems of Mechanical Engineering
    8
  • ITMO University
    5
  • Ioffe Institute
    4
  • Bauman Moscow State Technical University
    3
  • //ror.org/02x91aj62:Peter the Great St. Petersburg Polytechnic University
    3
  • Tver State Technical University
    2
  • Kuban State University
    2
  • Saint Petersburg State University
    2