Materials physics and mechanics

RAR RUS 1-7 I.I. Polzunov Altai State Technical University Starostenkov

Barnaul, Russia

Menoufia University Aish

Egypt

Molecular dynamic study for ultrathin nickel nanowires at the same temperature Molecular Dynamics (MD) simulations have been carried out on pure ultrathin Nickel (Ni) crystal with face-centered cubic (FCC) lattice upon application of uniaxial tension at nanolevel with a speed of 20 m/s. The deformation corresponds to the direction . To the calculated block of crystal - free boundary conditions are applied in the directions , . Morse potential was employed to carry out three dimensional molecular dynamics simulations. A computer experiment is performed at a temperature corresponding to 10 K, 300 K and 1000 K. MD simulation used to investigate the effect of long of ultrathin Ni nanowire on the nature of deformation and fracture. The engineering stresstime diagrams obtained by the MD simulations of the tensile specimens of these ultrathin Ni 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 four regions: quasi-elastic, plastic, flow and failure. The results showed that breaking position depended on the nanowire length. Ni nanowires; MD simulation https://mpm.spbstu.ru/article/2014.35.1/ MPM121_01_aish.pdf

RAR RUS 8-16 Islamic Azad University Bueenzahra Branch Dardashti

Bueenzahra, Iran

Islamic Azad University Bueenzahra Branch Sedighi

Bueenzahra, Iran

Thermal analysis of bimetal plates as cooking pots: computational comparison of two geometries Multi-layer-plate (MLP) provides improved thermal, chemical and mechanical properties. High temperature degree, uniform Temperature Distribution (TD), heat capacity and inertness of utensil material are significant parameters in cooking. In this study the main objective is analysis of the TD all over the two different structure of cookware. Analyzed structures have different behavior so we can use them in different propose. In another part we concerned about heat loss from heated cookware. We compared the insulated pan with non-insulated pan. Based on results the insulator improved the heat retaining of pan. It reduces the energy consumption. We employed Finite Element Method (FEM) for analyzing transient thermal behavior of models. temperature distribution; finite element method; cookware; bi-layer plate https://mpm.spbstu.ru/article/2014.35.2/ MPM121_02_sedighi.pdf

RAR RUS 17-28 Dalian University of Technology Fei

Dalian, China

Dalian University of Technology Dong

Dalian, China

Dalian University of Technology Zongjin

Dalian, China

Dalian University of Technology Zhenyuan

Dalian, China

Dalian University of Technology Liqi

Dalian, China

Stress analysis and simulation on piezoelectric quartz wafer under multidimensional forces Based on mechanics of anisotropic material and Maxwell's electromagnetic theory, the piezoelectric effect of piezoelectric material (SiO2) under multidimens ional forces has been studied. Exploring the distributions of stress field and polarization electric field inside the circular wafer, the piezoelectric equations between forces and induced charge on wafer's surface are established. Then the simulation analysis is performed by the FEM, obtaining polarization electric field and electric potential in the wafer. Results of both analyses show that f dividing the wafer's surface into four areas, the quantity of electric charge on each area is linearly related to bending moments and normal force, which gives a new way to measure multidimensional forces by a single quartz wafer. The study also provides the theoretical feasibility for developing a novel small-size multidimensional forces sensor. piezoelectric quartz wafer; multidimensional forces; stress analysis; FEM analysis https://mpm.spbstu.ru/article/2014.35.3/ MPM121_03_dong.pdf

RAR RUS 29-37 Peter the Great St. Petersburg Polytechnic University Gruzdev

St.Petersburg, Russia

T-5749-2017 6602123579 0000-0002-2102-1076 Peter the Great St. Petersburg Polytechnic University Kodzhaspirov Georgij kodjaspirov@spbstu.ru

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Rudskoy Andrey

St.Petersburg, Russia

Modelling of the fine precipitates effect strengthening of Al-Mg-Si alloys under ageing The paper presents the results of modelling by numerical simulation of the fine precipitates effect on the strengthening of Al-Mg-Si alloys under ageing. The sequence of metastable modes including Genie-Preston Zones (GPZ) and needle-like β"-phase particles arised during the multistep ageing in the alloy are taken into account when the strengthening effect described by the model. The utilization of the distribution function of the particles and account for the shape of precipitates allows to interpret the experimental results by changing of yield strength during ageing with a high precision and correspondingly to predict strength of the alloy. alloy Al-Mg-Si; strengthening with fine particles https://mpm.spbstu.ru/article/2014.35.4/ MPM121_04_gruzdev.pdf

RAR RUS 38-49 Tula State University Treschov

Tula, Russian Federation

Tula State University Telichko

Tula, Russia

Tula State University Khodorovich

Tula, Russia

Modeling stress-strain state thick cylindrical shells made of materials with complicated properties A modification of three-dimensional finite element in the form of a tetrahedron for calculating three-dimensional structures is considered. We derive a stiffness matrix for a finite element in the form of a tetrahedron with three degrees of freedom at the node. A model of the problem of determining stress-strain state thick cylindrical shells is developed. shell; anisotropy; orthotropy; stress-strain state; different resistance; finite element https://mpm.spbstu.ru/article/2014.35.5/ MPM121_05_khodorovich.pdf

RAR RUS 51-57 FSBEI HPE “Kh.M. Berbekov Kabardino-Balkarian State University” Mikitaev

Nalchik, Russia

FSBEI HPE “Kh.M. Berbekov Kabardino-Balkarian State University” Kozlov

Nalchik, Russia

The efficiency of polymer nanocomposites reinforcement by disperse nanoparticles The efficiency of small (∼ 6 nm) and large (~ 80 nm) nanoparticles as nanofiller for polymer nanocomposites has been studied. It has been shown that the indicated efficiency depends on both initial nanoparticles size and their aggregation degree. The last effect suppression can be give essential influence for nanoparticles of small size only. nanocomposite; disperse particles; efficiency; aggregation; interfacial adhesion https://mpm.spbstu.ru/article/2014.35.6/ MPM121_06_kozlov.pdf

RAR RUS 58-70 Institute of Problems of Mechanical Engineering RAS Aero

St.Petersburg, Russia

Institute of Problems of Mechanical Engineering, Russian Academy of Sciences Korzhenevskii

St.Petersburg, Russia

The theory of coexisting austenite-martensite phase formation A two-dimensional lattice model of austenite-martensite transformation is considered. The model Hamiltonian contains a periodic term and gradient ones. The mixed gradient terms are included to account for the coupling of internal structural degrees of freedom of the complex lattice with the conventional acoustic displacements. The exact solutions that describe the coexisting incommensurate austenite-martensite structures are obtained. The results explain the appearance so called premartensitic superlattice reflections that are typically observed near the transformations. martensitic transformations; austenitic-martensitic coexisting phases; two-dimensional microstructures; nonlinear theory of the formation https://mpm.spbstu.ru/article/2014.35.7/ MPM121_07_aero.pdf

RAR RUS 71-77 Ioffe Institute S.N. Rodin

St.Petersburg, Russia

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

St.Petersburg, Russia

Ioffe Institute Shcheglov

St.Petersburg, Russia

Ioffe Institute Bessolov

St.Petersburg, Russia

Ioffe Institute Konenkova

St.Petersburg, Russia

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

Ioffe Institute Myasoedov

St.Petersburg, Russia

Semipolar GaN on Si(001): the role of SiC buffer layer synthesized by method of substrate atom substitution The new HVPE method has been developed for synthesis of semipolar gallium nitride on the substrate of Si(100) deviated on 2°-7° from the direction . The method is based upon the formation of two buffer layers. First, the thin buffer layer (20-30nm) of SiC is formed, which is grown using the technology of substitution of part of silicon atoms in substrate of Si by carbon atoms, then the layer of AlN is deposited on this surface. It has been shown that the misorientation of Si substrate from the direction and formation of the thin SiC layer permit to form the epitaxial layers of semipolar gallium nitride. The polar axis c of wurtzite crystal appeared to be deflected by 55° from the plane (100) of Si substrate. The obtained films of semipolar GaN had a half-width of the rocking curve FWHM of the order of ω~24'. The thickness of GaN films was in the limits of 10-14 microns. The structure GaN/AlN/SiC/Si(100) formed during this process exhibited a bending of a cylindrical form. The formation of this bending is explained by anisotropy of the deformation of semipolar GaN on silicon. crystal structure; hydride vapor phase epitaxy; nitrides https://mpm.spbstu.ru/article/2014.35.8/ MPM121_08_kukushkin.pdf

RAR RUS 78-98 0000-0002-0437-8540 Mechanical Engineering Research Institute, Russian Academy of Science Perevezentsev

Nizhni Novgorod, Russia

Mechanical Engineering Research Institute, Russian Academy of Science Sarafanov

Nizhni Novgorod, Russia

Mechanical Engineering Research Institute, Russian Academy of Science Svirina

Nizhni Novgorod, Russia

Computer simulation of the dislocation ensemble kinetics in the elastic fields of mesodefects and fragmentation processes during plastic deformation The analysis of the elementary processes of fragmentation (broken sub-boundaries and a misorientation band formation) is performed by the discrete dislocation computer simulation method. It is shown that a fragmentation driving force is a decrease of the system energy due to the dislocations redistribution in the elastic field of primary mesodefects (disclinations, dipoles of disclinations et al.) accumulating on the grain boundaries and triple junctions during plastic deformation. The comparison of the results with the results obtained by continual approach is made. The misoriented structures formation inside shear bands during plastic deformation of mono--crystals is considered. It is shown that this process is similar to the polycrystal fragmentation, but in this case dislocation clusters accumulating near shear band interface act as the primary mesodefects. An analysis of conditions of low-angle sub-boundaries trasformation into medium-angle boundaries is performed. plastic deformation; fragmentation; dislocations; disclinations; computer simulation https://mpm.spbstu.ru/article/2014.35.9/ MPM121_09_perevezentsev.pdf