Materials physics and mechanics

RAR RUS 817-822 Ufa State Petroleum Technological University Apkadirova

Ufa, Russia

Ufa State Petroleum Technological University Krylova

Ufa, Russia

Institute for Metals Superplasticity Problems of Russian Academy of Sciences Mulyukov

ufa

Dehydrogenation of a crumpled graphene flake: molecular dynamics Using molecular dynamics simulation, the dehydrogenation process of a crumpled graphene flake during annealing at 77, 100, 150, 200, 250, and 300 K for 200 ps is considered. It is found, that annealing at T = 77 K during the first 50 ps does not affect the gravimetric density. Further, exposure at this temperature results in a sharp decrease in the gravimetric density to 7.6 wt.%. It is found that the higher the temperature, the faster the dehydrogenation process of the carbon structure. At annealing temperatures above 150 K, the gravimetric density of crumpled graphene is set to a constant value, and an increase in the annealing time does not lead to a change of gravimetric density. This is because some of the hydrogen atoms remaining in the structure are deposited on the edge carbon atoms, forming a strong covalent bond that cannot be broken at such temperature. 10.18149/MPM.4762021_1 molecular dynamics crumpled graphene dehydrogenation https://mpm.spbstu.ru/article/2021.85.1/ 1-N_G_-Apkadirova%2C-K_A_-Krylova%2C-R_R_-Mulyukov.pdf

RAR RUS 823-829 Institute of Problems of Mechanical Engineering RAS Bobylev S.V.

St.Petersburg, Russia

113263 6701854079 0000-0001-9909-2950 Institute of Problems of Mechanical Engineering RAS Sheinerman Alexander

St.Petersburg, Russia

Effect of grain size distribution on the yield strength of metal-graphene composites A theoretical model describing the effect of grain size distribution in the metal matrix of metal-graphene composite on its yield strength. The model describes the initial stage of plastic deformation in metal-graphene composites and takes into account both dislocation mechanisms of plasticity and the process of grain boundary sliding. The yield strength of the aluminum-graphene composite was calculated depending on the average grain size of the matrix and the volume fraction of graphene. Our analysis shows that the presence of dispersion in the grain size distribution of the metal matrix decreases the yield stress so special attention should be paid to reducing this dispersion during the synthesis of the composite. 10.18149/MPM.4762021_2 metal-graphene composites ultrafine-grained materials yield strength grain boundary sliding https://mpm.spbstu.ru/article/2021.85.2/ 2-S_V_-Bobylev%2C-A_G_-Sheinerman.pdf

RAR RUS 830-842 Kalasalingam University Amuthakkannan

Krishnankoil, India

Kalasalingam University Manikandan

Tamilnadu, India

Kalasalingam University Uthayakumar

Tamilnadu, India

Kalasalingam Academy of Research and Education Arun Prasath

India

Kalasalinagm Academy of Research Education Sureshkumar

Krishnankoil, India

Investigation of the machining performance of basalt fiber composites by abrasive water jet machining The abrasive water jet machining technique is a contemporary approach for cutting the materials without any thermal distortion with small cutting forces. The basalt fiber reinforced polymer composites are material with superior mechanical properties compared to glass fiber composites. The aim of the current study focused on the cutting parameters (travel speed of nozzle, standoff distance, and pressure of water) of abrasive water jet machining (AWJM) for the machining of basalt fiber composites using Grey Relation analysis. The top kerf, bottom kerf, and kerf angle are considered as output parameters and based on the grey relation optimization, the optimum process parameters are water pressure (240 MPa), traverse speed (20 m/s), and standoff distance (1mm). The results revealed that the water pressure is highly influencing machining parameter. When increasing water pressure, the increases of the kerf was observed and Standoff distance increases the delamination of the composites. 10.18149/MPM.4762021_3 basalt fiber polymer composite AWJM Grey Relation analysis https://mpm.spbstu.ru/article/2021.85.3/ 3-P-Amuthakkannan-et-al.pdf

RAR RUS 843-855 Peter the Great St. Petersburg Polytechnic University Ermakov

St. Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Shvecov

St. Petersburg, Russia

Features of obtaining powders for additive machines by plasma spraying The authors of this work have developed a model range of plasma atomizers, allowing to realize rapid production of metal powders of various chemical compositions. Up to date, powders of ferrous – low-alloy and carbon steels, stainless chromium-nickel and chromium-nickel-manganese steels, titanium, copper, niobium alloys, and heat-resistant alloys have been manufactured and have passed industrial testing, proving the possibility of their use in additive machines. The paper presents data confirming the possibility of using the method of plasma spraying of solid feedstock to obtain high-quality powders for additive machines and the results of studies of the influence of plasma spraying energy-power parameters on the geometric dimensions of the resulting powders, their crystal structure, and main characteristics. Data on the mechanical properties of samples made from sprayed powders are also provided. 10.18149/MPM.4762021_4 additive technologies plasma spraying powders plasma atomizers https://mpm.spbstu.ru/article/2021.85.4/ 4-Ermakov-Sergey%2C-Shvecov-Oleg.pdf

RAR RUS 856-863 ITMO University Rozhkov

St.Petersburg, Russia

ITMO University Smirnov A.M.

St.Petersburg, Russia

N-7717-2016 7005519053 0000-0003-4116-4821 Institute of Problems of Mechanical Engineering RAS Kolesnikova Anna anna.kolesnikova.physics@gmail.com

St. Petersburg, Russia

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

St.Petersburg, Russia

Molecular dynamics modeling of the mechanical behavior of YSZ-ceramics/graphene nanocomposite Within the framework of the molecular dynamics method, the mechanical behavior of a graphene nanoinclusion in a matrix of zirconium dioxide stabilized by yttrium oxide has been simulated. The analysis of the possibility of using the existing interatomic interaction potentials developed for these crystals in model mechanical tests of the nanocomposite is carried out. It is shown that pristine graphene is an excellent reinforcing element of the composite since it is deformed without the formation of defects in the range of small and medium strain values. The artificial creation of small pores of 3 Å in diameter in the intermediate layers also makes a little effect on the destruction of the graphene nanoinclusion. The creation of pores of 5 Å in diameter and more can lead to cracking of the nanoinclusion. To improve the accuracy of the model and to observe the destruction of the sample under study, the need to develop new potential for interatomic interaction is demonstrated. 10.18149/MPM.4762021_5 nanocomposites ceramics graphene molecular dynamics https://mpm.spbstu.ru/article/2021.85.5/ 5-M_A_-Rozhkov-et-al.pdf

RAR RUS 864-871 0000-0003-2484-346X Kazan Federal University Romanova

Kazan, Russia

0000-0002-7947-801X Kazan Federal University Shafigullin

Kazan, Russia

0000-0001-8407-8144 Ogarev Mordovia State University Erofeev

Saransk, The Republic of Mordovia, Russia

0000-0003-2106-6271 Kazan Federal University Bobryshev

Kazan, Russia

Investigating failure of automotive components made of polydicyclopentadiene Today, polydicyclopentadiene (PDCPD) is a promising polymeric material for automotive components. It is a liquid moulding resin that is processed via a reaction injection moulding system. PDCPD is used to make a kit of parts for KAMAZ vehicle "lower belt", bumper face guards, air intakes. It was found during the operation that the KAMAZ side step frame made of PDCPD failed. The comprehensive investigation revealed that the causes of the part failure were environmental factors, thermal degradation, quality of the raw materials, as well as failure to comply with the production process. The study of the IR spectra of PDCPD samples showed that the failed part (unlike the standard samples) featured a more intensive peak at around 1745 cm-1, which corresponded to the vibrations of carbonyl groups –С=О, which was indicative of the formation of the oxidized structures. The probability of formation of these structures can be a result of the thermal oxidation of the end product due to violation of the production process, operation at increased temperatures, and UV exposure, as well as low-quality raw materials. 10.18149/MPM.4762021_6 polydicyclopentadiene automotive components failure defects https://mpm.spbstu.ru/article/2021.85.6/ 6-N_V_-Romanova%2C-L_N_-Shafigullin%2C-V_T_-Erofeev%2C-A_A_-Bobryshev.pdf

RAR RUS 872-884 Aliah University Mohibul Khan

Kolkata, India

Aliah University Sk. Faruque Ahmed

Kolkata, India

Effect of the distance between cathode and substrate on structural and optical properties of zinc oxide thin films deposited by RF sputtering technique Zinc oxide (ZnO) thin films have been fabricated over glass substrates via Radio Frequency (RF) sputtering technique with varying distances between cathode and substrate. The aim of the fabrication of thin films was to study the structural, morphological, compositional, and optical properties by varying the distance between cathode and substrate. X-Ray Diffractometer (XRD) has been used to discuss the structural property of deposited thin films. The XRD patterns of fabricated ZnO thin films indicate wurtzite hexagonal crystal phase at miller indices (002) by a high intense peak at the Bragg's angle 34.4o . Crystallite size of fabricated ZnO thin films decreases from 32 nm to 17 nm with increasing the distance between cathode and substrate from 65 nm to 125 nm respectively, which have been calculated using XRD (002) peak. The information about morphological characteristics of the surface of ZnO thin films has been discussed by using Atomic Force Microscope. Some information about the bonding of fabricated ZnO thin films has been studied by Fourier Transform Infrared Spectroscopy. UV-VIS spectrophotometer has been used to investigate the optical property and Urbach parameter of the deposited ZnO thin films. Optical energy, which is also known as bandgap energy, increases from 3.16 eV to 3.25 eV with increasing the distance between cathode and substrate from 65 nm to 125 nm respectively. Urbach energy i.e., defect density decreases from 195 meV to 182 meV with the increasing the distance between cathode and substrate from 65 nm to 125 nm respectively. The change in optical transmittance, optical band gap energy, and Urbach energy has been discussed in terms of nanostructure ZnO thin films 10.18149/MPM.4762021_7 ZnO thin films RF sputtering technique XRD FT-IR Optical bandgap energy Urbach energy https://mpm.spbstu.ru/article/2021.85.7/ 7-Mohibul-Khan%2C-Sk_-Faruque-Ahmed.pdf

RAR RUS 885-895 Peter the Great St. Petersburg Polytechnic University Reztsova

St. Petersburg, Russia

Mathematical modelling of ice beam deflection dynamics The assessment of stresses arising from the interaction of the ice field and inclined structures is an important part of research in ice mechanics. For these purposes, various mathematical tools are used, including mechanical models of beams. The article presents solutions for the equation of dynamic deflection of a beam with different boundary conditions, as well as taking into account the influence of a liquid located under the ice field. The inclusion of the base reaction in the beam deflection equation allows us to obtain an alternative model, which in some cases turns out to be more accurate than others. The obtained solutions are tested on the results of our own experiments conducted in an ice basin with model ice. In the experiments, the velocity of structures was varied; force projections, time, and place of the ice beam failure were recorded. 10.18149/MPM.4762021_8 cantilever beam bending dynamics ice-structure interaction model ice https://mpm.spbstu.ru/article/2021.85.8/ 8-A_M_-Reztsova.pdf

RAR RUS 896-904 Kalasalingam Academy of Research and Education Arun Prasath

India

PSR College of Engineering Amuthakkannan

India

Kalasalingam University Manikandan

Tamilnadu, India

Kalasalingam Academy of Research and Education Kavitha

Tamilnadu, India

Nadar Saraswathi College of Engineering and Technology Radhkrishnan

Tamilnadu, India

Study of mechanical properties of copper slag reinforced particulate polymer composite Copper slag is one of the by-products that is extracted from the copper waste, during the smelting process. It is an environmentally friendly material that also, has some industrial benefits too. The composite prepared using this copper slag improves the mechanical strength of the products. From this, an idea to promote over some of the waste to enhance the strength of the composite for effective mechanical applications. In this paper, the tensile, flexural, and impact mechanical strength of the copper (Cu) slag powder in different weight percentages as 5wt. %, 10wt. %, 15wt. %, and 20wt. % were analyzed. The composites were fabricated with hand layup techniques. The mechanical properties of the composites were tested using the universal testing machine for tensile and flexural tests and Izod impact tester for an impact study. These results show the different mechanical behaviours of the varying copper weight percentage in the composites was observed with enhanced mechanical properties. SEM analysis gives information about the poor bonding, micropores, and lack of copper inclusion in the various weight percentage copper slag reinforced in the polyester composite. 10.18149/MPM.4762021_9 copper slag polyester resin particulate composite mechanical properties SEM morphology. https://mpm.spbstu.ru/article/2021.85.9/ 9-K_-Arunprasath-et-al.pdf

RAR RUS 905-920 Institute of the Applied Mechanics Russian Academy of Science Lurie

Moscow, Russia

Institute of applied mechanics RAS Belov

Moscow, Russia

Institute of applied mechanics RAS Lykosova

Moscow, Russia

Specifics of symmetry conditions in gradient elasticity theories The conditions of symmetry of the common Mindlin types gradient theories of elasticity, which characterize the specificity of these theories in comparison with the classical theory of elasticity, are investigated. We discuss the symmetry conditions of the tensors of the moduli of elasticity of the sixth rank under the permutation of the differentiation indices, which are the consequence of the fact that the second derivatives of the displacement vector do not depend on the order of differentiation. The gradient distortion model and strain gradient model are considered, and the conditions for "variational equivalence" and the differences between these theories from the point of view of symmetry are established. The variational formulation of gradient elasticity of general form and the role of symmetry conditions in the formulation of boundary conditions are investigated. It is shown that for the correct formulation of applied boundary value problems, it is necessary to use the tensors of the elastic moduli of the sixth rank symmetric with respect to the permutation of the last two indices in each triple of indices, even if this symmetry is absent for formally constructed versions of gradient theories. 10.18149/MPM.4762021_10 strain gradient theory; elasticity; variational methods; classification of symmetries https://mpm.spbstu.ru/article/2021.85.10/ 10-S_-Lurie%2C-A_-Belov%2C-D_-Lykosova.pdf

RAR RUS 921-936 University of Sfax Bouazizi

Sfax, Tunisia

University of Sfax Turki

Sfax, Tunisia

Combined effects of viscous dissipation and Brownian motion on temperature distribution and heat transfer of Al2O3/water nanofluid flow through a porous medium The combined effect of viscous dissipation and Brownian motion, especially on temperature distribution and heat transfer, has been carried out. Results show that there is an increase in temperature values throughout the field with the increase in the Eckert number Ec, this can be proven by the additional source of thermal energy (heat) provided by viscous dissipation in the porous medium, but it makes a decrease in heat transfer. For a lower Darcy number Da, the Brownian motion effect is negligible. Without Brownian motion, the averaged Nusselt number reveals an increase when nanoparticles volume fraction 10.18149/MPM.4762021_11 nanofluids viscous dissipation Brownian motion temperature distribution heat transfer thermal energy https://mpm.spbstu.ru/article/2021.85.11/ 11-Lotfi-Bouazizi-Bouazizi%2C-Said-Turki.pdf

RAR RUS 937-950 Chuvash State University Frolova

Cheboksary, Russia

Institute for Problems in Mechanical Engineering of the Russian Academy of Sciences Vilchevskaya

St.Petersburg, Russia

Effective diffusivity of transversely isotropic material with embedded pores The paper is concerned with the calculation of the effective diffusivity of transversely isotropic material with spheroidal pores by means of effective field methods. The segregation effect that is the main difference between conductivity and diffusivity problems is taken into account. Wiener's and Hashin-Shtrikman's bounds are modified to account for the segregation. Orientational scatter of pores about a preferential orientation is considered. MoriTanaka, Kanaun-Levin, and Maxwell homogenization schemes in terms of property contribution tensors are used. The calculated diffusion coefficients depend on the volume fraction, the shape of pores, their distribution over orientations in a three-dimensional solid, and the segregation factor. 10.18149/MPM.4762021_12 effective field methods effective diffusivity segregation effect bounds for diffusivity https://mpm.spbstu.ru/article/2021.85.12/ 12-K_P_-Frolova%2C-E_N_-Vilchevskaya.pdf

RAR RUS 951-961 Guru Nanak Dev University Singh

India

Khalsa College Singh

Amritsar, India

Guru Nanak Dev University Kaur

India

Khalsa College Singh

Amritsar, India

Lyallpur Khalsa College Kaur

Jalandhar, India

Guru Nanak Dev University Singh

India

The role of lead oxide in PbO-B2O3 glasses for solid state ionic devices Physical and optical properties of xPbO-(100-x) B2O3 (x=20-50 mol %) lead-borate glasses were investigated. The density of these glass samples increases from 4.267 to 5.960 g/cm3 whereas the molar volume decreases initially and then increases continuously as the content of PbO increases. PbO's dual role (modifier and glass former) in the glassy matrix is responsible for the non-uniform variation in density and the uneven pattern in molar volume. The UV-visible spectra also revealed a non-uniform variation in optical band gap with increasing PbO content, confirming that PbO enters the glass network as a modifier at low concentrations and as a glass former at high concentrations. Other parameters, such as average boron-boron separation and oxygen packing density (OPD) decrease progressively as PbO content increases, while the refractive index, the molar volume of oxygen (V0) and packing density (Vt) increase linearly. Because of the presence of lead, the ionic behaviour of the prepared glasses increases while covalency decreases, indicating that these can be used to make solid state ionic devices. 10.18149/MPM.4762021_13 Borate Glasses; Optical Properties; Density; Molar Volume https://mpm.spbstu.ru/article/2021.85.13/ 13-Gurinder-Pal-Singh-et-al.pdf

RAR RUS 962-967 Lobachevsky State University of Nizhni Novgorod Bragov

Nizhny Novgorod, Russia

Lobachevsky State University of Nizhni Novgorod Gonov

Nizhni Novgorod, Russia

Lobachevsky State University of Nizhni Novgorod Lamzin

Nizhny Novgorod, Russia

Lobachevsky State University of Nizhni Novgorod Lomunov

Nizhni Novgorod, Russia

Lobachevsky State University of Nizhni Novgorod Modin

Nizhni Novgorod, Russia

Response of fine-grained fiber-reinforced concretes under dynamic compression The article presents the results of tests of different types of fiber-reinforced concrete in comparison with concrete-matrix. The dynamic experiments were carried out using the split Hopkinson bar technique on samples of fine-grained concrete-matrix, as well as with the addition of steel and polypropylene fiber. The static tests of these materials were carried out using the Z100 Zwick-Roell testing machine. Diagrams of deformation and dependences of maximum stresses versus the stress rate are constructed. The obtained data were used to determine the values of the incubation failure time of the studied materials. The influence of the stress rate on the strength of the materials and the applicability of the structural-temporal approach for the prediction of this effect is shown. 10.18149/MPM.4762021_14 fiber-reinforced concrete split Hopkinson pressure bar stress rate incubation time criterion https://mpm.spbstu.ru/article/2021.85.14/ 14-A_M_-Bragov%2C-M_E_-Gonov%2C-D_A_-Lamzin%2C-A_K_-Lomunov%2C-I_A_-Modin.pdf

RAR RUS 968-977 Motilal Nehru National Institute of Technology Allahabad Kumar

India

Motilal Nehru National Institute of Technology Allahabad Bharti

India

Optimization of powder metallurgy process parameters to recycle AZ91 magnesium alloy A global increase in the demand for magnesium and its alloys has put increased pressure on magnesium's natural sources (magnesium ores) due to its high strength-to-weight ratio and environment-friendly nature. Therefore, it has become necessary to look for efficient recycling techniques for magnesium and its alloys. Powder metallurgy proved to be very efficient compared to conventional recycling techniques for the recycling of aluminum, copper, and other alloys. In the present work, an experimental study was done to see the suitability of powder metallurgy for recycling magnesium and its alloy. Optimization of process parameters (compaction pressure, sintering temperature, and sintering time) was done with respect to AZ91 magnesium alloy's sintered density because almost all the properties (i.e., physical, mechanical, electrical, thermal, etc.) of a powder metallurgy product are dependent on the sintered density. Sintered density is dependent on the extent of diffusion and the thermal expansion in the material. And the extent of diffusion and the thermal expansion depends on the compaction pressure, sintering temperature, and sintering time. After experimental and statistical investigations, it was observed that compaction pressure is the most influencing parameter. The optimum set of process parameters was found out to be a combination of compaction pressure of 450MPa, the sintering temperature of 723K, and sintering time of 2h. 10.18149/MPM.4762021_15 ANOVA AZ91 Mg Alloy powder metallurgy sintered density Taguchi https://mpm.spbstu.ru/article/2021.85.15/ 15-Naveen-Kumar%2C-Ajaya-Bharti(1).pdf

RAR RUS 978-986 ITMO University Tsarev

St.Petersburg, Russia

ITMO University Bazhenov

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Odnoblyudov

St.Petersburg, Russia

ITMO University Alodjants

St.Petersburg, Russia

On physical properties of few-photon detectors based on structures with micropillars We develop the model of micropillar photodetectors operated in the infrared domain. The model is based on an algorithm, which uses analytical methods and numerical simulation of Schrödinger equation, aimed at the calculation of the energy levels and wave functions of a semiconductor micropillar. We define the heterostructure as a combination of different semiconductor materials grown one on top of the other via epitaxial methods. The photon-detecting scheme is based on the fact that electrons in potential wells have different energies, and the transition between them (including tunneling) is induced by the absorption of a quantum of energy. The most probable optical transitions are verified; two particular transitions corresponding to the infrared range are demonstrated and relevant photo-current dependencies are discussed. 10.18149/MPM.4762021_16 photodetector micropillar semiconductor heterostructure https://mpm.spbstu.ru/article/2021.85.16/ 16-Bazhenov-et-al.pdf