https://www.elibrary.ru/title_about_new.asp?i 1605-8119 24 4 2015 1-101

RAR RUS 309-318 Institute of Problems of Mechanical Engineering RAS Nazarov

St.Petersburg, Russia

Modeling of densely cracked surfaces and the Griffith energy criterion of fracture Considering an elastic homogeneous isotropic body with a periodic family of surface microcracks, it is observed and justified rigorously that an influence of the microcracks on the far-field stress-strain state of the body can be taken into account at an appropriate asymptotic precision in a certain norm by creation of an asymptotic-variational model for an elastic dummy obtained by clipping out a thin near-surface layer of the elastic material. In other words, an abatement of a solid resistance due to the surface damage is equivalent to spalling of a subsurface flake realized in the model as a regular shift of the exterior boundary along the interior normal. The asymptotic-variational model is consistent with both, the Griffith energy criterion of fracture and spectral characteristics (e.g., eigenfrequencies) of the damaged body. At the same time, the traditional modelling through so-called "wall-laws" or singularly perturbed boundary conditions of Wentzel's type leads to ill-posed spectral problems. Numerical schemes for the asymptotic-variational model in the designed regularly perturbed domain do not differ from the ones in the original elastic body with a smooth intact surface that is without microcracks that makes the proposed approach to interpret damaged surfaces efficient. surface microcracks; densely cracked surfaces; the Griffith energy criterion of fracture https://mpm.spbstu.ru/article/2015.44.1/ MPM424_01_nazarov.pdf

RAR RUS 319-324 Institute for Problems of Mechanical Engineering of the RAS Semenov

St.Petersburg, Russia

St.-Petersburg State University Smirnov

St.Petersburg, Russia

St.-Petersburg State University Sudenkov

St.Petersburg, Russia

St.-Petersburg State University Tatarinova

St.Petersburg, Russia

Effect of heat treatment on the mechanical properties of ultrafine-grained aluminium The paper presents the results of experimental studies of mechanical properties of ultrafine-grained aluminum with a grain size of 700±200 nm resulting from the intensive plastic deformation by torsion of technical aluminum AD1 in combination with different modes of heat treatment. It is shown that microhardness and tensile strength of fine-grained material exceed the values of microhardness and tensile strength of the material as supplied more than two times and the elongation is reduced more than twice. It is noted that various modes of annealing after the intensive plastic deformation by torsion can lead to embrittlement of the material and increase its ductility. ultrafine-grained aluminium; heat treatment; microhardness; tensile strength https://mpm.spbstu.ru/article/2015.44.2/ MPM424_02_semenov.pdf

RAR RUS 325-330 Peter the Great St. Petersburg Polytechnic University Grishchenko

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

Modeling inelastic deformation of single crystal superalloys with account of γ / γ' phases evolution Using single-crystal nickel-base superalloys for the gas turbine blades allows significantly increase the operating temperature and consequently the economy of gas turbine engine. At the microscopic level, the single-crystal nickel base alloys are structures consisting of two phases: γ'-phase, forming on the basis of Ni3Al, which is dispersed in a matrix of γ-phase, representing a solid solution of alloying elements in nickel. On the basis of finite element homogenization the analysis of the influence of phase composition on the stress-strain diagram, as well as study the effect of the shape evolution of γ'-inclusion, occurring during the formation of raft structures, on the creep curves are performed. The results of simulations demonstrate a good agreement with experimental data for a single crystal nickel-base superalloy ZhS32. single crystal nickel base superalloy; phase composition; finite element modeling; stress-strain diagram; creep curves https://mpm.spbstu.ru/article/2015.44.3/ MPM424_03_grishchenko.pdf

RAR RUS 331-339 Institute Silicate Chemistry of Russian Academy of Science Konakov V.G.

St.Petersburg, Russia

Institute of Problems of Mechanical Engineering RAS I.A. Ovid’ko И.А.

St.Petersburg, Russia

Institute Silicate Chemistry of Russian Academy of Science Solovyeva E.N.

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Kurapova

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Novik

St.Petersburg, Russia

Institute Silicate Chemistry of Russian Academy of Science Pivovarov M.M.

St.Petersburg, Russia

Synthesis and mechanical properties of "nanonickel-nanoceramic" composites The paper reports synthesis of bulk nanocomposites from nanosized nickel and yttrium-stabilized zirconia powders. Characteristics of the phase composition of the synthesized composites and their microstructure are experimentally revealed. Mechanical properties of the composites are experimentally measured and discussed as those depending on the nanoceramic phase content. With the experimental data, it is concluded that the mechanical strength of the nanocomposites remains high enough in a wide range of nanoceramic phase concentrations. "nanonickel-nanoceramic" composite; phase composition; microstructure; mechanical properties https://mpm.spbstu.ru/article/2015.44.4/ MPM424_04_konakov.pdf

RAR RUS 340-346 Institute Silicate Chemistry of Russian Academy of Science Konakov V.G.

St.Petersburg, Russia

Institute Silicate Chemistry of Russian Academy of Science Solovyeva E.N.

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Kurapova

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Novik

St.Petersburg, Russia

Institute Silicate Chemistry of Russian Academy of Science Pivovarov M.M.

St.Petersburg, Russia

Scientific and Technical Center “Glass and Ceramics” Archakov

St.Petersburg, Russia

"Nickel-YSZ-nanoceramics" nanocomposite: synthesis, structure, and mechanical properties The approach for "nickel-YSZ-nanoceramics" bulk nanocomposite synthesis was developed. Compositions with the nanoceramic phase content lying in the range up to 20 wt.% YSZ were manufactured; their structure and chemical composition were studied using XRD, SEM, and EDX techniques. Experimental study of the composite mechanical properties (compressive strength) as a function of sample composition demonstrated the existence of maximal composite strength at YSZ content of 3 wt.%. Further addition of nanoceramic phase resulted in the significant decrease in material strength. "nickel-YSZ-nanoceramics" nanocomposite; chemical composition; microstructure; mechanical properties https://mpm.spbstu.ru/article/2015.44.5/ MPM424_05_konakov.pdf

RAR RUS 347-358 Institute of Problems of Mechanical Engineering RAS Meshcheryakov Yu.I.

St.Petersburg, Russia

Institute of Problems of Mechanical Engineering RAS Zhigacheva

St.Petersburg, Russia

Institute of Problems of Mechanical Engineering RAS Divakov

St.Petersburg, Russia

Institute for Problems of Mechanical Engineering of the RAS Konovalov

St.Petersburg, Russia

The CRISM “Prometey” Barakhtin

St.Petersburg, Russia

Tomsk State University Razorenov

Tomsk, Russia

St.-Petersburg State University Vyvenko

St.Petersburg, Russia

St.-Petersburg State University Bondarenko

St.Petersburg, Russia

Physics of Metals Institute RAS Khomskaya

Ekaterinburg, Russia

Shock-induced structures in copper Shock loading of M3 copper within strain rate range of 5·106 - 5,7·106 s-1 reveals a nucleation of structural objects of 5-30 µm in diameter, which present the three dimensional frameworks composed from shear bands of 50-200 nm spacing. The structures are shown to be nucleated by means of interference of longitudinal and periphery release waves. Transition of the material into structure unstable state responsible for the shear banding happens when rate of change of the velocity variance at the mesoscale becomes higher than the rate of change of the mean particle velocity. The sites of nucleation of 3D-structures are speculated to be the staking faults generated under action of chaotic velocity pulsations relevant to dynamic deformation. The physical model for formation of 3D-structures takes into account the intersection of the partial dislocations and Lomer - Cottrell barriers. shock loading; shear bands; stacking fault; partial dislocations; framework structures https://mpm.spbstu.ru/article/2015.44.6/ MPM424_06_meshcheryakov.pdf

RAR RUS 359-363 Altai State Technical University Poletaev Gennady M.

Barnaul, Russia

I.I. Polzunov Altai State Technical University Starostenkov

Barnaul, Russia

Lobachevsky State University of Nizhni Novgorod Novosel’tseva

Nizhny Novgorod, Russia

Molecular dynamics study of the thermal stability of Ni3Al nanoneedles The study of the thermal stability of Ni3Al nanoneedles in the dependence on the sharpness and crystallography orientation of the needle axis was held using molecular dynamics method. It is shown that the most stability nanoneedles in the conditions of thermal influence are the ones with the axis along [111] direction. Violation of the nanoneedles stability associated with their blunting, which is caused by surface diffusion. Stable radius of curvature of the needles at low temperatures, depending on the angle of the tip and orientation of the needle axis, is 0.6-1 nm. Ni3Al nanoneedles; thermal stability; molecular dynamics https://mpm.spbstu.ru/article/2015.44.7/ MPM424_07_poletaev.pdf

RAR RUS 364-373 Institute of Problems of Mechanical Engineering RAS I.A. Ovid’ko И.А.

St.Petersburg, Russia

7003559440 0000-0003-2192-0386 Institute for Problems of Mechanical Engineering RAS Skiba Nikolai nikolay.skiba@gmail.com

St. Petersburg, Russia

Influence of nanotwins on stress-driven migration of grain boundaries in deformed nanomaterials A theoretical model is suggested which describes grain boundary migration under external mechanical load in nanomaterials containing ensembles of nanotwins. In the framework of the model, a disclination description of stress-driven migration of grain boundaries in grains initially containing nanotwins. The energy characteristics and critical stresses for such a migration process are calculated. These critical stresses are compared with those specifying needed for stress-driven migration of grain boundaries in the absence of nanotwing in the exemplary cases of nanocrystalline and ultrafine-grained copper. nanomaterials; migration of grain boundaries; nanotwins https://mpm.spbstu.ru/article/2015.44.8/ MPM424_08_skiba.pdf

RAR RUS 374-381 Saint Petersburg State University E.G. Zemtsova

St.Petersburg, Russia

St.Petersburg State University Morozov

St.Petersburg, Russia

Saint Petersburg State University Smirnov

St.Petersburg, Russia

Regulation of surface topography of nanostructured titanium using the method of ML-ALD to create bioactive nanocoatings The paper considers the regulation of the structural characteristics of the surface of a new medical material - nanotitan due to the application of nanostructured titanium organic coating brush type using the method of molecular layering ML-ALD. Established the important role of the conditions of surface preparation of metallic substrates prior to synthesis. It was established experimentally that by changing the temperature of the surface preparation and the number of cycles of processing nanotitanium, you can adjust the nanorelief titanium organic nanostructures brush type: the height of the nanostructures from 7 nm to 150 nm; the distance between the nanostructures is from 10 to 220 nm; the size of the nanostructures (length along the X axis) from 25 to 120 nm. nanotitanium; regulation of surface topography; method of molecular layering https://mpm.spbstu.ru/article/2015.44.9/ MPM424_09_smirnov.pdf

RAR RUS 382-390 Institute Silicate Chemistry of Russian Academy of Science Konakov V.G.

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Kurapova

St.Petersburg, Russia

Peter the Great St. Petersburg Polytechnic University Novik

St.Petersburg, Russia

Scientific and Technical Center “Glass and Ceramics” Golubev

St.Petersburg, Russia

Microstructure of "copper-graphene" composites manufactured by electrochemical deposition using graphene suspensions stabilized by non-ionic surfactants The approach for "copper-graphene" composites electrochemical deposition using graphene suspensions stabilized by non-ionic surfactants (polyacrylic acid and pluronic F-127) was developed. The produced coatings were studied by SEM and XRD. As a result, graphene and surfactant contents were optimized to achieve high quality of the composite surface. It has been shown that the type of non-ionic surfactant highly affects composite microstructure and its crystallinity. "copper-graphene" composite; microstructure; SEM; XRD https://mpm.spbstu.ru/article/2015.44.10/ MPM424_10_konakov.pdf

RAR RUS 391-402 Zhengzhou University Li

Zhengzhou, China

Zhengzhou University Li

Zhengzhou, China

Zhengzhou University Tie

Zhengzhou, China

Zhengzhou University Yu

Zhengzhou, China

Influence of patch parameters on damage and residual strength of adhesively bonded composite repair under fatigue loading A progressive fatigue damage analysis method was developed to predict damage propagation and residual strength of the adhesively bonded repairs in composites subjected to constant amplitude cyclic loading. The fatigue damage models of adhesively bonded repairs are respectively established with different shapes of the patches. Based on the theory of the residual strength and residual stiffness in composites, the material property degradation technique for modifying element stiffness and strength and materials ultimate failure criteria were proposed. This program is able to simulate progressive fatigue damage and predict residual strength of the adhesively bonded repairs in composites subjected to constant amplitude cyclic loading with different shapes of the patches. The calculation results of damage model show that the patch shape and size are important fatigue design parameters of adhesively bonded repairs. The effect of repair with tilted square patch is the best than others and the residual strength improves by 27.6 % than the unrepaired composite laminates. composite material; 3-D progressive fatigue damage model; patch shape; residual strength https://mpm.spbstu.ru/article/2015.44.11/ MPM424_11_li.pdf

RAR RUS 403-409 Menoufia University Aish

Egypt

The University of Jordan Shatnawi

Amman, Jordan

I.I. Polzunov Altai State Technical University Starostenkov

Barnaul, Russia

Characterization of strain-induced structural transformations in CdSe nanowires using molecular dynamics simulation In this work, we have successfully applied the method of molecular dynamics simulation to simulate structural transformations in CdSe nanowire when subjected to a tensile deformation along the direction. The time evolution of atomic configuration and the energy of deformation were calculated. These quantities clearly revealed four distinct structural transformations that take place during the tensile deformation, namely: the quasi-elastic, plastic, flow and fracture. Our results indicate that the deformation process starts with the appearance of vacancies, Frenkel pairs and interstitial atoms, after which atomic displacement, dislocation, anti-phase boundary and grain boundary formation take place before slipping and alloy fracture. CdSe nanowires; uniaxial tension; molecular dynamics simulation; strain energy https://mpm.spbstu.ru/article/2015.44.12/ MPM424_12_aish.pdf