Materials physics and mechanics

RAR RUS 1-7 Ioffe Institute Mynbaeva

St.Petersburg, Russia

Ioffe Institute Sitnikova

St.Petersburg, Russia

Ioffe Institute Smirnov

St.Petersburg, Russia

Ioffe Institute Mynbaev

St.Petersburg, Russia

Aalto University Lipsanen

Aalto, Finland

ITMO Univesity Kremleva

St.Petersburg, Russia

ITMO University Bauman Dmitrii

St.Petersburg, Russia

ITMO University V.E. Bougrov

St.Petersburg, Russia

F-1445-2014 7202768874 0000-0003-3738-408X ITMO University Romanov Alexey alexey.romanov@niuitmo.ru

St.Petersburg, Russia

On cracking in thick GaN layers grown on sapphire substrates Self-organization mechanisms promoting elimination of cracks in thick GaN layers grown on sapphire substrates are considered on the basis of the experimental results on the fabrication of the layers by Hydride Vapor-Phase Epitaxy on MOCVD-grown GaN/Al2O3 templates. The obtained data support the supposition on the closure of tensile stress-related cracks via diffusion processes and demonstrate the strong contribution of bulk diffusion in addition to surface diffusion discussed earlier. 10.18720/MPM.4412020_1 GaN defects cracking Hydride vapor phase epitaxy https://mpm.spbstu.ru/article/2020.75.1/ MPM144_01_mynbaeva.pdf

RAR RUS 8-18 Politecnico di Milano Comi

Milano, Italy

Politecnico di Milano Moscatelli

Milano, Italy

Ecole polytechnique Marigo

Palaiseau, France

Two scale homogenization in ternary locally resonant metamaterials In this work, we exploit the two-scale homogenization approach to compute explicitly the band gaps for out-of-plane wave propagation in ternary locally resonant metamaterials (LRM) with two-dimensional periodicity. The homogenization approach, recently developed by the authors for binary LRM, leads to the definition of the dynamic effective mass density, depending on the frequency, that becomes negative near the resonant frequencies of the inclusions. The intervals of negative effective mass give the band gaps. These explicit solutions put in evidence the dependence of the spectral gaps on the geometric parameters of the unit cell and on the mechanical properties of the three constituent materials. The range of frequency where the asymptotic homogenization approach is equivalent to the Bloch-Floquet theory is also established and confirmed by numerical simulations. 10.18720/MPM.4412020_2 metamaterials homogenization effective mass band gaps wave propagation https://mpm.spbstu.ru/article/2020.75.2/ MPM144_02_comi.pdf

RAR RUS 19-25 ITMO University Kaminskii

St.Petersburg, Russia

ITMO Univesity Liubimova

St.Petersburg, Russia

F-1445-2014 7202768874 0000-0003-3738-408X ITMO University Romanov Alexey alexey.romanov@niuitmo.ru

St.Petersburg, Russia

Probing of polycrystalline magnesium at ultrasonic frequencies by mechanical spectroscopy In the present work, using the method of a composite piezoelectric oscillator at a frequency of 99-102 kHz, polycrystalline magnesium was studied under two types of treatment: deformation and subsequent annealing. The influence of these types of treatments on changes in the dislocation density and such an important structurally sensitive parameter as the dynamic Young's modulus has been established. The values of micro-yield stress are determined. With a longitudinal deformation of 1.7%, at the strain amplitude of 5×10-6 , its value decreased from 2.9 MPa to 1.7 MPa; after annealing at 400 °C, it increased to 5.8 MPa. 10.18720/MPM.4412020_3 Magnesium mechanical spectroscopy dislocation density Young's modulus internal friction microplastic deformation https://mpm.spbstu.ru/article/2020.75.3/ MPM144_03_kaminskii.pdf

RAR RUS 26-33 Altai State Technical University Poletaev Gennady M.

Barnaul, Russia

Siberian State Industrial University Zorya

Novokuznetsk, Russia

Altai State University Rakitin

Barnaul, Russia

Financial University under the Government of the Russian Federation, Barnaul brunch Iliina

Barnaul, Russia

I.I. Polzunov Altai State Technical University Starostenkov

Barnaul, Russia

Interaction of impurity atoms of light elements with vacancies and vacancy clusters in fcc metals The interaction of impurity atoms of light elements C, N, O with vacancies and vacancy clusters in fcc metals Ni, Ag and Al was studied by the molecular dynamics method. The binding energies of impurity atoms with vacancies, divacancies and stacking fault tetrahedron (SFT) are calculated. It is shown that the impurity atom in a vacancy is not located at its center, but is displaced relative to it in the direction of the type. The changes in the activation energy of vacancy migration upon interaction with an impurity atom are calculated. When studying the interaction of impurity atoms with a SFT, it was found that the binding energy of C, N and O atoms for all the considered metals is higher with the SFT edge (i.e. with partial dislocation) than with the top of the SFT. 10.18720/MPM.4412020_4 molecular dynamics metal vacancy impurity binding energy divacancy vacancy cluster stacking fault tetrahedron https://mpm.spbstu.ru/article/2020.75.4/ MPM144_04_poletaev.pdf

RAR RUS 34-47 University of Tabriz Aghajani

Tabriz, Iran

University of Tabriz Hosseini

Tabriz, Iran

Arak University Mirzakhani

Arak, Iran

Deposition kinetics and boundary layer theory in the chemical vapor deposition of β-SiC on the surface of C/C composite In this study, SiC was deposited on carbon/carbon (C/C) composite substrate using chemical vapor deposition (CVD) method to investigate the kinetics of the deposition process. Therefore, the time, temperature, precursor composition (SiCl4:N2:CH4) and substrate position in the reactor were varied to evaluate the deposition rate. X-ray diffraction (XRD) method was used to characterize the phase composition and calculate the grain size and the texture coefficient of the coatings. Field emission scanning electron microscopy (FESEM) was utilized to observe the coating morphology, microstructure and thickness. As observed β-SiC was the dominant phase of the coating with varied preferred growth crystalline planes of (111), (220) or (311). The coating thickness was 2 µm and 5 µm for the samples treated at 1000 and 1100°C, respectively. 10.18720/MPM.4412020_5 chemical vapor deposition boundary layer deposition rate SiC coating C/C composite https://mpm.spbstu.ru/article/2020.75.5/ MPM144_05_aghajani.pdf

RAR RUS 48-60 School of Chemical Engineering, Northwest University Zheng

China

School of Chemical Engineering, Northwest University Li

China

Strain-hardening effect on critical strain assessment of pipe plastic bending at buckling In the current paper, the characteristic factor β=[1 +0.904(σb / σs) · (1-σs / σb)] is extracted from the analytical solution of the bending moment for a rectangular strainhardening beam first. Thereafter, the characteristic factor β is transplanted into the previously proposed assessment of the critical buckling strain for rigid-perfectly plastic bending pipe by analogy method, thus an extended expression of the critical buckling strain for a pipe plastic bending including strain-hardening effect is developed, εc=0.19tr⋅(1+11.78r)⋅[0.096+0.904/(1−n)2].εc=0.19tr⋅(1+11.78r)⋅[0.096+0.904/(1−n)2]. Moreover, available test data is employed to check the suitability of the extended expression. The results show that the extended expression is reasonable to reveal the effect of Hollomon type strain-hardening behavior on the critical buckling strain of pipe plastic bending. 10.18720/MPM.4412020_6 plastic bending buckling critical strain strain-hardening pipe https://mpm.spbstu.ru/article/2020.75.6/ MPM144_06_zheng.pdf

RAR RUS 61-65 Institute for Problems of Mechanical Engineering of the RAS Bratov

St.Petersburg, Russia

Moscow State University of Civil Engineering Ilyashenko

Moscow, Russia

Ishlinsky Institute for Problems in Mechanics RAS Kuznetsov

Moscow, Russia

National Chiao Tung University Lin

Hsinchu, Taiwan

7005573911 St.Petersburg State University Morozov N.F.

St.Petersburg, Russia

Homogeneous horizontal and vertical seismic barriers: mathematical foundations and dimensional analysis The concept of a vertical barrier embedded in soil to protect from seismic waves of the Rayleigh type is discussed. Horizontal barriers are also analyzed. The principle idea for such a barrier is to reflect and scatter energy of an oncoming wave by the barrier, thus decreasing the amplitude of surface vibrations beyond the barrier. Numerical FE simulations of a plane model are presented and discussed. 10.18720/MPM.4412020_7 seismic protection seismic barrier Rayleigh waves Lamb problem https://mpm.spbstu.ru/article/2020.75.7/ MPM144_07_bratov.pdf

RAR RUS 66-76 Prince Sattam Bin Abdulaziz University Bassiouny

Saudi Arabia

Hyperbolic two temperature fractional order one dimensional thermoelastic model heated by a pulse of laser The behaviour of an isotropic homogeneous thermoelastic semi-infinite medium is investigated based on the acceleration of conductive and thermodynamic temperatures. A half-space x ≥ 0, under stress-free boundary condition at the near end, is considered. At this near end, a laser pulse decaying exponentially with time is applied. In the framework of fractional order generalized thermoelasticity theory, a one-dimensional coupled model is reduced using Laplace transform and corresponding thermally-induced temperature, stress and strain distribution functions are determined in the Laplace domain. Different inverse field functions are investigated numerically through a complex inversion formula of Laplace transform. The behavior of the field functions with different parameters are studied and presented graphically. Comparisons with the classical two temperature model are discussed. 10.18720/MPM.4412020_8 hyperbolic two temperatures fractional order strain fractional order equation of motion laser short pulse thermal loading generalized thermoelasticity https://mpm.spbstu.ru/article/2020.75.8/ MPM144_08_bassiouny.pdf

RAR RUS 77-82 Udayana University Suardana

Bali, Indonesia

Udayana University Sugita

Badung, Bali, Indonesia

Udayana University Wardana

Badung, Bali, Indonesia

Hybrid acoustic panel: the effect of fiber volume fraction and panel thickness The composite panel test were made of gypsum, pumice powder, and glue with composition of 1:2:1/2 and coconut fiber with volume fraction variation of 10%, 15%, 20%, 25%, and 30% by using Hand lay-up technique. The sound absorption panel was tested for acoustic and mechanical characteristic using test standard with ASTM E1050, ASTM D256, and ASTM D790, respectively. The result of data analysis was presented graphically and the bounding of composite materials was analysed by using SEM photograph. From the data analysis for 10mm thickness of composite with 30% fiber volume fraction gained the highest sound absorption coefficient, the highest impact strength occurred on composite with 25% fiber volume fraction. Meanwhile, the strength and modulus of bending occurred on composite with 15% fiber volume fraction. Sound absorption coefficient for composite with 15mm thickness was higher than 10mm for 10% fiber volume fraction. 10.18720/MPM.4412020_9 pumice waste coconut fiber gypsum acoustic and mechanic https://mpm.spbstu.ru/article/2020.75.9/ MPM144_09_suardana.pdf

RAR RUS 83-93 Menoufia University Aish

Egypt

Structural transformation of HCP metallic nanowireusing cleri-rosato potential Sub-atomic Dynamic simulations have been carried out on some single-crystal hexagonal metals, HCP nanowires (Cd, Co, Mg, Ti, and Zr) upon application of uniaxial tension with a speed of 20 m/s and to investigate the nature of deformation and fracture. The deformation corresponds to the direction plane. A many-body interatomic potential for HCP nanowires within the second-moment approximation of the tight-binding model (the Cleri-Rosato potentials) was employed to carry out three dimensional MD simulations. A computer experiment is performed at a temperature 300K. The stored energy diagrams obtained at various time by the MD simulations of the tensile specimens of these metallic nanowires show a rapid increase in stress up to a maximum followed by a gradual drop to zero when the specimen fails by ductile fracture. The feature of deformation energy can be divided into three regions: quasi-elastic, plastic and failure. The nature of deformation, slipping, twinning and necking were studied. Stress decreased with increasing volume and the breaking position increases. The results showed that breaking position depended on the nanowire length. From this, it appears that Cleri-Rosato potentials make good represent for the deformation behavior of HCP metallic nanowires. 10.18720/MPM.4412020_10 molecular dynamics uniaxial tension Cleri-Rosato nanowires tight-binding and failure https://mpm.spbstu.ru/article/2020.75.10/ MPM144_10_aish.pdf

RAR RUS 94-102 Southern Federal University Soloviev

Rostov-on-Don, Russia

Southern Federal University Chebanenko

Rostov-on-Don, Russia

University of Applied Sciences and Arts Northwestern Switzerland Zhilyaev

Windisch, Switzerland

Southern Federal University Cherpakov

Rostov-on-Don, Russia

Southern Federal University Parinov

Rostov-on-Don, Russia

Numerical optimization of the cantilever piezoelectric generator In this paper, we consider the adequacy of the use of the straight normal hypothesis in the applied theory for the calculation of a cantilever-type piezoelectric generator that takes into account the incomplete piezo-element coating of the substrate, which was obtained earlier, and a numerical optimization procedure for piezoelectric generator is given, taking into account critical failure stresses. 10.18720/MPM.4412020_11 piezoelectric generator banding straight normal semi-analytical method finite element numerical optimization https://mpm.spbstu.ru/article/2020.75.11/ MPM144_11_soloviev.pdf

RAR RUS 103-109 Ioffe Institute Krasinkova

St.Petersburg, Russia

Single-walled carbon nanotube as a nanoscale quantum system It is shown that a single-walled carbon nanotube based on a carbon monolayer (graphene) rolled up into a cylinder is a nanoscale quantum system characterized by the presence of electron crystals, like graphene. In contrast to the extremely unstable graphene quantum system, the nanotube quantum system is stable at a certain curvature of the carbon skeleton. The curvature causes the redistribution of π electrons between internal and external electron crystals accompanied by the formation of additional one-dimensional or quasi-onedimensional crystals of pairs of π* electrons excited into a higher 3s2pz energy state and located on the nanotube external side. The stability of the nanotube quantum system and its unusual physical properties are due to these crystals of π* electron pairs. 10.18720/MPM.4412020_12 carbon nanotubes electron crystals nanoscale quantum systems ballistic conductivity https://mpm.spbstu.ru/article/2020.75.12/ MPM144_12_krasinkova.pdf

RAR RUS 110-115 Tomsk State University of Control Systems and Radioelectronics (TUSUR) Sakharov

Tomsk, Russia

Structure and properties of nanoporous oxide dielectrics modified by carbon A physical method of receiving nanoporous films of the silicon dioxide (SiO2) and tantalum pentoxide (Ta2O5) in vacuum conditions is brought forward in this work. The structure and properties of nanoporous films received as a result of self-organization at magnetron spattering of a compound target are researched in it. Correlations of the quantity and size of pores, the structure and properties of nanoporous films are determined, as well. The self-organization process proves to form spatially spattered pores, to change electrophysical properties of dielectric films and it enlarges their functions. 10.18720/MPM.4412020_13 nanoporous oxide films carbon self-organization process magnetron spattering https://mpm.spbstu.ru/article/2020.75.13/ MPM144_13_sakharov.pdf

RAR RUS 116-124 Peter the Great St. Petersburg Polytechnic University Krasnitckii S.A.

St.Petersburg, Russia

ITMO University Smirnov A.M.

St.Petersburg, Russia

0000-0003-0727-6352 Institute of Problems of Mechanical Engineering RAS Gutkin M. Yu.

St.Petersburg, Russia

Pair interaction of coaxial circular prismatic dislocation loops in elastic solids with spherical surfaces In the present work, the pair interaction of coaxial circular prismatic dislocation loops (PDLs) arbitrary placed in elastic solids with free spherical surfaces is considered. The analytical solutions for the pair interaction energies of PDLs in an elastic sphere, an elastic medium with a spherical pore and a spherical layer are given in the form of double power series and illustrated by energy maps built in the space of the normalized PDL radii and axial positions. The results can be used for analyzing the theoretical models of stress relaxation processes in bulk and hollow core-shell nanoparticles and pentagonal particles, which occur through the formation of dislocation ensembles. 10.18720/MPM.4412020_14 prismatic dislocation loops dislocation ensembles stress relaxation https://mpm.spbstu.ru/article/2020.75.14/ MPM144_14_krasnitckii.pdf

RAR RUS 125-136 Peter the Great St. Petersburg Polytechnic University Savikovskii

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Semenov Artem

St.Petersburg, Russia

Polzunov Central Boiler and Turbine Institute, Getsov

St.Petersburg, Russia

Crystallographic orientation, delay time and mechanical constants influence on thermal fatigue strength of single - crystal nickel superalloys The influence of a delay time at the maximum temperature on the number of cycles for the macrocrack initiation for two thermal loading programs was investigated for two single-crystal nickel-based superalloys VIN3 and ZhS32. An analytic approximation of a delay time influence was proposed. Comparison of computational results and analytic formula on the base of constitutive equations with the experimental data was performed for considered single-crystal superalloys and showed a good accuracy. Influence of several mechanical constants of nickel alloy on thermal fatigue strength is presented and discussed. The influence of crystallographic orientation of the corset sample on the thermal fatigue durability with delay times for various thermal loading programs and different single-crystal nickel superalloys was investigated. 10.18720/MPM.4412020_15 thermal fatigue single-crystal nickel-based superalloy deformation criterion corset sample crystallographic orientation finite element modeling analytic approximation https://mpm.spbstu.ru/article/2020.75.15/ MPM144_15_savikovskii.pdf

RAR RUS 137-158 Institute of Electrophysics, Ural Branch of RAS Boltachev

Ekaterinburg, Russia

Institute of Electrophysics, Ural Branch of RAS Chingina

Ekaterinburg, Russia

Institute of Electrophysics, Ural Branch of RAS Volkov

Ekaterinburg, Russia

Institute of Electrophysics, Ural Branch of RAS Lukyashin

Ekaterinburg, Russia

Elastic properties, yield surface and flow rule of nanopowder compacts Different compaction processes of the nanosized granular system, which is a prototype of an alumina nanopowder, are studied by the granular dynamics method. For all processes: compaction curves “density vs. pressure” of the powder compact are calculated, the elastic and the plastic parts are extracted from the total deformation, the body elastic moduli are determined within the isotropic solid approximation. The inadequacy of the isotropy approximation is established. The nanopowder yield surface is constructed in the space of stress tensor invariants. The inapplicability of the traditional associated flow rule for description of oxide nanopowders compaction processes is revealed. An alternative flow rule is suggested. 10.18720/MPM.4412020_16 nanopowder yield surface associated flow rule https://mpm.spbstu.ru/article/2020.75.16/ MPM144_16_boltachev.pdf