Materials physics and mechanics

RAR RUS 1-13 University of Salerno Iovane

Fisciano (SA), Italy

Southern Federal University Nasedkin

Rostov-on-Don, Russia

Finite element modelling of ceramomatrix piezocomposites by using effective moduli method with different variants of boundary conditions The paper presents an investigation of effective properties of piezocomposites of piezoceramic/polycrystallites type by using the effective moduli method, the computer modeling of representative volumes with random structure of granular heterogeneity and the finite element method to solve the homogenization problems. The effective moduli, obtained from the problems with different boundary conditions on the edges of representative volumes, are analyzed. 10.18720/MPM.4212019_1 piezoelectricity two-phase piezocomposite effective moduli representative volume finite element method finite element software https://mpm.spbstu.ru/article/2019.69.1/ MPM142_01_iovane.pdf

RAR RUS 14-19 ITMO Univesity V.G. Dubrovskii

St.Petersburg, Russia

Geometry of GaAs nanowire seeds in SiOx/Si (111) templates We present an energetic model to describe the initial stage of growth of GaAs nanowire seeds in SiOx/Si (111) templates. The model explains the experimentally observed geometry of GaAs seed crystal emerging from Ga droplets in the holes, with either stepwise or ring geometry at the outer periphery of the holes and restricted by the steps that are much larger than monoatomic. Understanding and controlling this geometry is crucial for further growth of nanowires, improving their vertical yield and optimizing the morphology and crystal structure. 10.18720/MPM.4212019_2 GaAs nanowires Ga droplet elastic stress relaxation surface energy silicon templates https://mpm.spbstu.ru/article/2019.69.2/ MPM142_02_dubrovskii.pdf

RAR RUS 20-29 Peter the Great St. Petersburg Polytechnic University Silnikov

St.Petersburg, Russia

Special Materials Corp. Guk

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Mikhaylin

St.Petersburg, Russia

St.Petersburg State University Nechunaev

St.Petersburg, Russia

Ioffe Institute Rumyantsev

St.Petersburg, Russia

Numerical simulation of hypervelocity impacts of variously shaped projectiles with thin bumpers The paper presents a numerical simulation of hypervelocity impacts of variously shaped projectiles with thin bumpers. A numerical model was verified using a full-scale experiment of hypervelocity impact of a sphere with thin aluminum-alloy bumper. Hypervelocity impacts of nonspherical projectiles of different spatial orientation with thin bumpers were also numerically investigated. The investigations show that a hypervelocity impact of a nonspherical projectile advancing with its sharp edge towards the bumper results in a denser debris cloud formation and, therefore, such an impact is more dangerous than any of other considered cases for the spaced protection. 10.18720/MPM.4212019_3 hypervelocity impact space debris non-spherical projectiles debris clouds Whipple shields https://mpm.spbstu.ru/article/2019.69.3/ MPM142_03_silnikov.pdf

RAR RUS 30-39 P-4505-2016 7006034020 0000-0002-2973-8645 Institute of Problems of Mechanical Engineering RAS Kukushkin S.A. sergey,a.kukushkin@gmail.com

St.Petersburg, Russia

Institute of Problems of Mechanical Engineering RAS Osipov A.V.

St.Petersburg, Russia

St.Petersburg State University Kasatkin

St.Petersburg, Russia

St.Petersburg State University Mikhailovskii

St.Petersburg, Russia

St.Petersburg State University Romanychev

St.Petersburg, Russia

Formation of ordered ZnO structures grown by the ALD method on hybrid SiC/Si (100) substrates Crystalline structure and composition of the ZnO films grown by atomic layer deposition (ALD) on the n- and p-type Si (100) substrates with a SiC buffer layer were studied. The SiC buffer layers have been synthesized by a novel method of atomic substitution (partial chemical replacement) of Si atoms by carbon atoms in the subsurface layer of the Si substrate. A four-component epitaxial texture of ZnO in a direction close to [101] on the n- and p-type (100) Si vicinal substrates with a SiC buffer layer has been revealed and investigated with electron diffraction. Formation mechanism of the epitaxial textures of ZnO was found to depend on the conductivity type (n- or p-type) of the Si (100) substrates. A theoretical model explaining the effect of the texture formation and its dependence on the type of Si substrate conductivity has been proposed. The effect is associated with the transformation of the vicinal Si (100) surfaces into the SiC surfaces during its synthesis by the atomic substitution method. Significant differences have been found between the structures and between the growth mechanisms of the ZnO layers on the SiC/Si (111) and (100) substrates. 10.18720/MPM.4212019_4 zinc oxide films ALD method silicon carbide; epitaxy; thin film growth https://mpm.spbstu.ru/article/2019.69.4/ MPM142_04_kukushkin.pdf

RAR RUS 40-53 RheinMain University of Applied Sciences Kirillova

Wiesbaden, Germany

Karlsruhe Institute of Technology Seemann

Karlsruhe, Germany

RheinMain University of Applied Sciences Shevtsova

Wiesbaden, Germany

The influence of an adhesive layer on the interaction between a piezo-actuator and an elastic 3D-layer and on the excited wave fields 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 the efficiency of the both methods used for calculation of the occuring wave fields: finite-element (FE) method and semi-analytical approach based on the Green’s matrix representations and the Fourier transform. 10.18720/MPM.4212019_5 anisotropic infinite layer Green's matrix piezoelectric actuator wave excitation finite element model Fourier transform https://mpm.spbstu.ru/article/2019.69.5/ MPM142_05_kirillova.pdf

RAR RUS 54-64 Southern Federal University Vatulyan

Rostov-on-Don, Russia

Southern Federal University Nesterov

Rostov-on-Don, Russia

On some features of identification of inhomogeneous prestressed state of thermoelastic hollow cylinder with coating 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 the operator equations of the first kind are solved. The most informative time intervals for gaining the additional information are determined. The influence of prestress level, coupling parameter and coating thickness on the results of prestress reconstruciton is analyzed. 10.18720/MPM.4212019_6 thermoelasticity prestress coating cylinder identification inverse problem https://mpm.spbstu.ru/article/2019.69.6/ MPM142_06_vatulyan.pdf

RAR RUS 65-73 Southern Federal University Soloviev

Rostov-on-Don, Russia

Southern Federal University Chebanenko

Rostov-on-Don, Russia

Southern Federal University Parinov

Rostov-on-Don, Russia

Southern Federal University Oganesyan

Rostov-on-Don, Russia

Applied theory of bending vibrations of a piezoelectric bimorph with a quadratic electric potential distribution An applied theory of cylindrical bending vibrations of a bimorph plate is developed, which takes into account the nonlinear distribution of the electric potential in piezoelectric layers. Finite-element analysis of this problem showed that such distribution arises when solving the problems of finding the resonant frequencies and modes of vibration or in the case of forced oscillations during their mechanical excitation, when the electric potentials on the electrodes are zero. The quadratic distribution of the electric potential adopted in the work showed good consistency of the results with finite-element calculations for natural oscillations and steady-state oscillations for a given potential difference when the electric potential distribution is close to linear. 10.18720/MPM.4212019_7 plate cylindrical bending electro elasticity nonuniform potential distribution https://mpm.spbstu.ru/article/2019.69.7/ MPM142_07_soloviev.pdf

RAR RUS 74-102 Southern Federal University Skaliukh

Rostov-on-Don, Russia

Mathematical 3D models of irreversible polarization processes of a ferroelectrics and ferroelastics polycrystal A review of three-dimensional mathematical models describing the irreversible processes of polarization of polycrystalline ferroelectrics is given. Experimental works and most frequently used models for describing hysteresis properties are considered. These include well-known phenomenological and micromechanical models. Some of them allow describing the nonlinear response under the action of electrical and mechanical loads. For each of the models, physical and mathematical features, basic formulas and calculating algorithms are presented. The main advantages and disadvantages of each of the presented models are noted. Large and small loops of dielectric and deformation hysteresis are shown. A conclusion is drawn about the unresolved problems in the field of modeling of polycrystalline ferroelectrics – ferroelastics. The list of works on the review topic is given. 10.18720/MPM.4212019_8 mathematical models ferroelectrics ferroelastics hysteresis loops phenomenological models micromechanical models https://mpm.spbstu.ru/article/2019.69.8/ MPM142_08_skaliukh.pdf

RAR RUS 103-111 Lobachevsky State University of Nizhni Novgorod Igumnov

Nizhni Novgorod, Russia

Don State Technical University Petrov

Rostov-on-Don, Russia

Lobachevsky State University of Nizhni Novgorod Vorobtsov

Nizhny Novgorod, Russia

The time-step boundary-element scheme on the nodes of the Lobatto method in problems of 3-D dynamic poroelasticity A boundary-element scheme for analyzing initial boundary-value problems of 3-D porelasticity is considered. The scheme is based on a time-step method of numerically inverting Laplace transform. According to the method, a solution in time is calculated using quadrature formulas, based on complex values of the function in specific points. The choice of the points is determined by Lobatto method being one of Runge-Kutta methods. A possibility of using two- and three-stage Lobatto methods is considered. Using as an example the problem about a force, acting upon end of a prismatic poroelastic body, the effect of timestep on the dynamic responses of the forces is studied. The present results are compared with the results obtained on the nodes of Radau method. 10.18720/MPM.4212019_9 boundary element method Runge-Kutta method poroelasticity transient dynamic analysis wave propagation https://mpm.spbstu.ru/article/2019.69.9/ MPM142_09_igumnov.pdf

RAR RUS 112-130 S.S.V. College, Hapur (C.C.S. University, Meerut) Kumar

India

S.S.V. College, Hapur (C.C.S. University, Meerut) Guatam

India

Mewar University Chand

Rajasthan, India

Mahamaya Government Degree College Kumar

Sherkot, Bijnore, India

S.S.V. College, Hapur (C.C.S. University, Meerut) Singh

India

First principle electronic, magnetic and thermodynamic characterization of heavy fermion ternary rare earth metal alloys Ternary rare earth metal alloys (viz. GdInZn, GdTlZn and GdInCd) play a key role in a large range of current research areas, in particular those devoted to heavy fermions, valence fluctuations, magneto-strictive materials, permanent-magnet materials, spin glasses and random anisotropy systems. Thus, to understand the relevant complex behavior of Gd/M/M¹, M=In, Tl; M¹ = Zn, Cd compounds (viz. GdInZn, GdInCd and GdTlZn), in the present research article, we have been carried out the theoretical investigations on electronic, magnetic and thermodynamic characteristics of Gd/M/M¹ type compounds in the hexagonal P63/mmc phase using density functional theory (DFT). 10.18720/MPM.4212019_10 structural properties electronic structure magnetic properties thermodynamic properties https://mpm.spbstu.ru/article/2019.69.10/ MPM142_10_kumar.pdf

RAR RUS 131-140 Universitas Pendidikan Indonesia Hamdani

Bandung, Indonesia

Universitas Pendidikan Indonesia Komaro

Bandung, Indonesia

IPB Irzaman

Bogor, Indonesia

A synthesis of BAxSR1-xTIO3 film and characterization of ferroelectric properties and its extension as random access memory Ferroelectric material is generally used in engineering fields for such purposes as sensors, microelectronics, etc. It also provides more advantages compared to ferromagnetic materials, especially those related to a memory storage. This is due to a stored memory produced from magnetic system only consists of 105 bits/cm2 whereas a memory from ferroelectric can be stored up to 108 bits/cm2 . The objectives of this study were 1) to develop BST films on Pt (200) / SiO2 / Si (100) substrates and p-type Si (100) substrates using the chemical solution deposition (CSD) method and 2) to test and study ferroelectric properties, XRD and SEM / EDS structure of the film produced. The research method used was an experiment, starting with the making of BST thin films, then ferroelectric tests, SEM / EDAX tests and XRD tests. The results of ferroelectric test show that all samples have ferroelectric properties. Therefore, annealing temperature affected a remanent polarization value and the coercive area of the sample. Regarding a memory application, BST (BAxSR1-XTIO3)1 M sample with 900°C of annealing temperature is the best material to be used since they have a high remanent polarization and a low coercive field. 10.18720/MPM.4212019_11 annealing BST ferroelectric ferromagnetic https://mpm.spbstu.ru/article/2019.69.11/ MPM142_11_hamdani.pdf

RAR RUS 141-150 Universitas Pendidikan Indonesia Hendrawan

Bandung, Indonesia

Universitas Pendidikan Indonesia Khoerunnisa

Bandung, Indonesia

Universitas Pendidikan Indonesia Ekawati

Bandung, Indonesia

Universitas Pendidikan Indonesia Sonjaya

Bandung, Indonesia

Preparation and physico-chemical properties of gracilaria/PVA/GA/CNT-based hydrogel for slow/controlled release material In this study, we synthesized a hydrogel from the extract of gracillaria (GR), poly- (vinyl alcohol) (PVA), glutaraldehyde (GA), and carbon nanotube (CNT). To confirm the synthesis of hydrogel, several characterizations were done, including fourier transform infra red (FTIR) and scanning electron microscope (SEM). Analysis on the material performance under various parameters (such as swelling ratio and release behavior of potassium from hydrogel into aqueous media) was also carefully evaluated based on weight measurement and flame-photometry instrumentation. FTIR spectra showed that the interaction of hydrogel components (GR, PVA, GA, CNT and Kalium-related material) involved some functional groups such as C-O, C-N, C=O, C-H sp3 as well as O-H which predominantly occurred through hydrogen bonding. The swelling ratio of technical-grade PVA-based hydrogel was higher than that of pro-analytical-grade. The hydrogel showed a typical slow release behavior for potassium ion with the release rate is 8.89 ppm for first ten minutes and the release rate average is 0.0134 ppm/minutes for the normal phase. 10.18720/MPM.4212019_12 hydrogel gracilaria poly-(vynil alcohol) CNT https://mpm.spbstu.ru/article/2019.69.12/ MPM142_12_hendrawan.pdf

RAR RUS 151-157 Universiti Malaysia Pahang Kurniawan

Pahang, Malaysia

Universiti Malaysia Pahang Anwar

Pahang, Malaysia

Universitas Pendidikan Indonesia Oktiani

Bandung, Indonesia

Universitas Pendidikan Indonesia Ragadhita

Bandung, Indonesia

Universitas Pendidikan Indonesia Nandiyanto

Bandung, Indonesia

The University of Tokyo Aziz

Tokyo, Japan

Influences of solvent types on the formation of graphene in the electrochemical exfoliation method The aim of this study was to evaluate the effect of different solvents in sonication process on the formation of graphene from the electrochemical exfoliation of graphite. In short, graphite rod was exfoliated by electrochemical process with ammonium sulfate as saltelectrolyte. The exfoliated powder then sonicated under two different solvents, which are Dimethylformamide (DMF) and aqueous solution to form graphene. It was found that similar structure of graphene was obtained from both types of solvent. However, the amount of graphene produced was different due to the differences in graphene stability. Graphene is more stable in DMF solvents compared to the aqueous solution. The aqueous solution can allow the reversible reaction that can reform graphite oxide from graphene due to the existence of hydroxyl component in the aqueous solution. 10.18720/MPM.4212019_13 graphene graphite electrochemical exfoliation solvent sonication https://mpm.spbstu.ru/article/2019.69.13/ MPM142_13_kurniawan.pdf