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The article considers a new methodology for specialist training in the field of microprocessor control systems based on filling an educational process with jobs of real practical content which’re performed by project team in the conditions of the access absence to a laboratory equipment. The matter is that during the study of theoretical disciplines of technical trend, practical classes, fulfilled in the form of laboratory works, are aimed at fundamental knowledge confirmation in a subject area by the way of experiment conduction, at that, experiments themselves can be organized not only on a laboratory equipment but also in modeling programs. The stated goals for theoretical information backing are achieved by fulfillment laboratory work and subsequent defense. Together, in training programs for specialists in applied technical spheres, for example, in the program of specialist preparation on "Control in technical systems" course, it’s provided the study of disciplines in which practical content prevails over theoretical one. Thus, for example, in the course "Electronics and fundamentals of microprocessor technology", it’s taught a necessary theoretical basis for the discipline "Microprocessor devices of control systems", and in the program itself of the pointed discipline, it’s provided the study of device construction approaches with the use of universal microprocessors and microcontrollers as well as of programming basics of them. Namely that is why in the curriculum of "Microprocessor devices of control systems" discipline, there’re provided not laboratory but practical works which in the course, students, performing tasks, program microcontrollers which interact with external devices in simple but functionally complete control devices. However, a laboratory equipment turns out to be unavailable during distance learning that predetermined the search for alternative forms of organization of practical works out-of-door of a university. The search for a suitable solution, besides the solution of laboratory equipment unavailability problem, led to the possibility to organize practical works with the use of a management project method.

The textbook sets and solves a number of scientific and applied tasks related to logistics and inventory management of resources for various purposes, among which raw materials and materials at industrial enterprises, goods in trading companies, as well as auxiliary materials (operational resources) purchased to support the life of organizations in various business areas. Procurement and inventory management is considered within a single set of functions, which is supply logistics. The issues related to the supply of operational resources, which are completely consumed in the course of economic activity of companies, transferring their value to the goods and services sold, are also considered. Meets the requirements of the federal state educational standards of higher education of the latest generation. For students, postgraduates and teachers of the main educational programs in economics and management, as well as for practitioners of procurement and inventory management companies, students of MBA programs, professional retraining and advanced training.

The paper presents a review of the potentials of interatomic interaction for studying the properties of structures with different types of crystal lattice. Tersoff potential, MEAM potential, and modified 2NN MEAM potential are considered.

Cubic shaped specimens with different angles between layer orientation and loading surface were tested quasistatically and dynamically. We found, that shear strength is slightly dependent on the compression load when the angle between layer orientation and load direction is in the range 30-60 degrees and increases 2 times at the angle 750. Material is strain rate sensitive but the behavior of the shear strength is the same at the high strain rates. transversal direction.

The paper considers a mechanism for constructing a model based on artificial neural network for obtaining the values of the cohesive energy of a system of atoms. Cohesive energy allows for calculation of total energy of system. It is one of the most important characteristics of a structure. A computational experiment is carried out for one-component crystal structures of Si, Ge and C.

This work was inspired by works of Gianfranco D’Anna (2000) where the Portevin-Le Chaˆtelier effect (PLC) was investigated by compressing Al-Mg alloy specimen in a very large deformation range and the results were interpreted from the viewpoint of phase transitions and critical phenomena. Two critical points where deformation process changes from “laminar” to jerky flow and back were noticed. We found that the second critical point where the rate of the serrations is decreased before the macroscopic fracture is not reachable for some alloys even with proposed geometry. We have tested 2 sets of specimens made of the same AMG6 alloy (~6% of magnesium) but with different amount of Si obtained from different producers. Specimens with a higher amount of Si tends to fracture before reaching the second point. Also, we have measured the amount of stored energy which can be recovered as heat during the annealing process. We used the differential scanning calorimeter STA "Jupiter" 449. We found that the amount of this energy sharply increases with the beginning of PLC serrations (first critical point) and drops at a second critical point or at macroscopic fracture. This can be related to a special type of critical phenomena—structural scaling transitions in mesodefect ensembles and associated structural relaxation mechanisms Naimark (2016)

The purpose of this work is to provide theoretical framework and experimental supporting evidence for a crucial role of structural transitions in the ensemble of defects at the meso-level (microshears and microcracks), as one of the mechanisms of plastic strain localization in metals under high-rate loading. The investigation of the sample response to dynamic loading was carried out on the split Hopkinson pressure bar and in a series of target penetration tests. To identify the characteristic stages of strain localization, the thermodynamics of the deformation process was investigated "in-situ" by recording the temperature fields using a high-speed infrared camera CEDIP Silver 450M. The temperature measured in the localization zone does not confirm the generally accepted concept of the strain localization mechanism as the mechanism governed by a thermoplastic instability. The samples stored after the experiment were subjected to microstructural analysis, using an optical interferometer-profilometer and a scanning electron microscope. The structural analysis revealed a correlated behavior of the ensemble of defects, which can be classified as a structural transition providing strain localization. The data of experimental studies, the examination of the structure of deformed samples, as well as the data of numerical modeling taking into account the kinetics of accumulation of microdefects in the material suggest that one of the mechanisms of plastic strain localization at high loading rates is associated with the jump-like processes in the defect structure of a material.

Tabs are used to protect the specimen from damage caused by applied grip loads during the test and to reduce stress concentrations. This paper aims at the investigation of strain localization and dissipation of energy in the adhesive layer in the high cycle fatigue test. A soft and thick adhesive layer is useful in the quasistatic test as it reduces the stress concentration. But the temperature rise due to the energy dissipation and the cracking in this layer may lead to erroneous results when advanced techniques such as thermography and acoustic emission are used

An experimental and theoretical study of fracture mechanisms of the AMg6 alloy at different structural levels was carried out under consecutive dynamic and fatigue tests associated with conventional catastrophic events of aircraft engine components (fan blades) due to the foreign object damage and the life-time decrease in the presence of a corrosive environment. The AMg6 alloy samples were preloaded dynamically using the split Hopkinson-Kolsky bar at the strain rates ∼103 s−1 and then subjected to the VHCF test up to 108–109 cycles at the Shimadzu USF-2000 resonance testing machine (the load frequency is 20 kHz) with the cooling by abundant compressed-air and salt fog (3% NaCl). The scaling analysis of fracture surface roughness was conducted to characterize quantitatively specific areas associated with the stages of damage-failure transition in the presence of the corrosion.

The phenomenon of plastic strain localization in alloys under dynamic loading was experimentally studied on a Hopkinson–Kolsky bar and during target penetration tests. The temperature fields generated during deformation were studied in situ using a CEDIP Silver 450M high-speed infrared camera with the aim to identify the characteristic stages of localized shear. The temperature field distribution obtained at different time allowed us to trace the evolution of plastic strain localization. Microstructural analysis of the post-test samples was carried out using an optical interferometer-profilometer and electron microscopes. The structural analysis provided evidence for the correlated behavior of the ensemble of defects, which can be classified as a structural transition responsible for the strain localization. The results of experimental studies, the study of the deformed sample structure, as well as the data of numerical simulation made with consideration for the evolution of microdefects in the material, suggest that one of the mechanisms of plastic strain localization in alloys under high-speed loading is caused by jump-wise processes in the defective structure of materials.

Experimental studies on the response of samples to dynamic loading were performed using a split Hopkinson-Kolsky bar and in a series of perforation tests. In-situ investigations of the thermodynamics of deformation processes made it possible to identify the characteristic deformation localization stages. Temperature fields were recorded with a high-speed infrared camera CEDIP Silver 450M, and strain localization in the samples was evaluated with a strain noninvasive measurement system StrainMaster. Temperature measurements made in the localization zone did not support a generally accepted concept that the strain localization mechanism is the mechanism governed by thermoplastic instability. The microstructural analysis of the samples stored after the experiment was carried out using an optical interferometer-profilometer and a scanning electron microscope. The analysis revealed the correlated behavior of the ensemble of defects, which can be classified as a structural transition providing strain localization. The data of experimental studies, the examination of the structure of deformed samples, as well as the data of numerical modeling performed with consideration of the kinetics of accumulation of microdefects in the material suggest that one of the mechanisms of plastic strain localization at high loading rates is associated with the jump-like processes in the defect structure of the material.

The behavior of specimens dynamically loaded during the split Hopkinson (Kolsky) bar tests in a regime close to simple shear conditions was studied. The lateral surface of the specimens was investigated in-situ using a high-speed infra-red camera CEDIP Silver 450M. The temperature field distribution obtained at different time allowed one to trace the evolution of plastic strain localization. The process of target perforation involving plug formation and ejection was examined using a high-speed infra-red camera and a VISAR velocity measurement system. The microstructure of tested specimens was analyzed using an optical interferometer-profiler and a scanning electron microscope. The development of plastic shear instability regions has been simulated numerically.

A very important task on the way of improving the technologies of synthesizing highly effective light-emitting diodes on the basis of silicon is theoretical research into the formation of point defect clusters. One method of obtaining silicon with photoluminescent properties is radiation impact. It causes the formation of various defects in its structure, including point and linear defects, their clusters and complexes. In this paper a mathematical model was used to determine the coordinates and velocities of all particles in the system. The model was used for describing point defect formation processes and studying their evolution with time and temperature. The multi-parametrical Tersoff potential was used for the description of interactions between particles. The values of the Tersoff potential were selected by solving the parametric identification problem for silicon. For developing the models we used the system cohesive energy values obtained by an ab initio calculation based on the density functional theory (DFT). The resultant computer model allows MD simulation of silicon crystal structure with point defects and their cluster with possible visualization and animation of simulation results.

Dynamic fragmentation of ceramic samples with different porosity were carried out using modified Hopkinson bar setup, which allow us to keep samples safe (in order to define fragment size distribution) and to measure fractoluminescence impulses occurred on the fracture surfaces (in order to establish the distribution of intervals between impulses). The analysis of experimental data reveals that the fragment size distribution and distribution of interval between fractoluminescence impulses obeys a power law, which exponent depends on ceramics porosity.

The paper focuses on the experimental and theoretical study of instability of plastic strain and its localization in materials subjected to high-velocity perforation. The online study of the specimen surface was made using the high-speed infrared camera CEDIP Silver 450M. The distribution of the temperature field obtained at different instants of time allows getting insight into the evolution of the process of plastic strain localization. After testing, the structure of the specimen material was examined by scanning electron microscopy. In our investigation, the mechanisms of plastic shear instability and localization of plastic strain (in the three-dimensional statement) have been simulated numerically, and the peculiarities of the kinetics of microshear accumulation in the material have been analyzed.

Experimentally observed universality of fluctuation statistics in fully developed turbulent shear flow is linked to the dynamics of collective shear localization modes and new class of critical phenomenon of solid with defects—structural-scaling transition. Universality appears as self-similarity of the distribution function of momentum power fluctuations on rotating discs (the Karman test) on the four orders of the Reynolds number that corresponds to the sharp power decay injected into the flow. Similar features of the coherent multiscale behavior established under multiscale plastic flow instability in AlMg alloy revealing the Portevin–Le Chatelier effect. Localized shears could be considered as mesoscopic structural defects in liquids appearing due to the collective molecular slips.

In this work digital image correlation method is used to study the spatio-temporal strain localization under uniaxial compression of granite samples and uniaxial tension of sylvinite specimens. These experiments showed that the sylvinite tension process realized as two consistently following forms of the spatio-temporal localization: a system of equidistant stationary foci of localized strain and a single stationary localized dissipative structure. Transition from one localization form to another occurs in the vicinity of the stress maximum. Under uniaxial granite compression the deformation process realizes as consistently propagating waves of localized strain on the specimen surface. It is shown that the velocity of the localized strain wave at 6-7 orders of magnitude smaller than the characteristic velocity of the elastic wave propagation in these materials and depends on the magnitude of an applied stress. At the final stage of deformation localized strain waves “gather” to the site of the main crack future exit on the lateral surface of the sample.

In this paper we investigate the fragmentation of tubular alumina samples under shock-wave loading. Test of tubular samples was performed on a universal experimental set up of electric explosion conductor Bannikova et al. (2013a). The blast tube destroyed into fragments having as rectangular or irregular geometric shapes. The mass distribution obtained by “method of photography” and “method weighting” are in good agreement Bannikova et al. (2013b). For tubes with wall thickness d = 2.05 mm formed fragments described of by double distribution: small fragments whose size is much smaller than the thickness of the tube - distribution power law, large fragments described as exponential and logarithmic distribution are equally. The inflection point of the distribution curves moves toward smaller scales with increasing energy density. Besides other determined that Weibull function a good description of the distribution of all the fragments by mass.

An extensive experimental investigation on zirconia ceramic specimens with different porosity was carried out to evaluate the influence of porosity on fractoluminescence pulse distribution and energy dissipation. Experiments were carried out using Split Hopkinson Pressure Bar (SPHB) setup with strain rate from 400 to 3000s-1. Porosity of the specimens was varied from 10% to 60% volume fraction. Energy dissipation was calculated from the SPHB data. Fractoluminescence was detected by a fast Photo Multiplier Tubes (PMT). Analysis of the fragment size distribution shows that it can be approximated by power law where power (slope in log-log coordinates) depends on the porosity. Fractoluminescence consists of pulses with sharp front and exponential decay with different amplitudes. Pulses were recorded even 1ms after the loading pulse, which is order of magnitude higher than load pulse duration. Intervals between subsequent pulses (or the rate of the pulses as in the Omori law) was measured. It was found, that interval complementary cumulative distribution is bimodal power law distribution. Knee position depends on the porosity of the specimen

The paper focuses on the experimental and theoretical study of plastic deformation instability and localization in materials subjected to dynamic loading and high-velocity perforation. We investigate the behavior of samples dynamically loaded during Hopkinson-Kolsky pressure bar tests in a regime close to simple shear conditions. Experiments were carried out using samples of a special shape and appropriate test rigging, which allowed us to realize a plane strain state. Also, the shear-compression specimens proposed in were investigated. The lateral surface of the samples was investigated in a real-time mode with the aid of a high-speed infra-red camera CEDIP Silver 450M. The temperature field distribution obtained at different time made it possible to trace the evolution of plastic strain localization. Use of a transmission electron microscope for studying the surface of samples showed that in the regions of strain localization there are parts taking the shape of bands and honeycomb structure in the deformed layer. The process of target perforation involving plug formation and ejection was investigated using a high-speed infra-red camera. A specially designed ballistic set-up for studying perforation was used to test samples in different impulse loading regimes followed by plastic flow instability and plug ejection. Changes in the velocity of the rear surface at different time of plug ejection were analyzed by Doppler interferometry techniques. The microstructure of tested samples was analyzed using an optical interferometer-profilometer and a scanning electron microscope. The subsequent processing of 3D deformation relief data enabled estimation of the distribution of plastic strain gradients at different time of plug formation and ejection. It has been found that in strain localization areas the subgrains are elongated taking the shape of bands and undergo fragmentation leading to the formation of super-microcrystalline structure, in which the size of grains is ~300nm. Rotational deformation modes give rise to the high angular disorientations of grains. The development of plastic shear instability regions has been simulated numerically. For this purpose, we use a recently developed theory, in which the influence of microshears on the deformation properties of materials has been studied by the methods of statistical physics and thermodynamics of irreversible processes. The results of theoretical and experimental studies suggest that one of the mechanisms of the plastic shear instability and localization of plastic strain at high-velocity perforation is related to structural and kinetic transitions in microshear ensembles.&nbsp

Tubular Al2O3 ceramic samples were destroyed under shock wave loading using electrical explosion wire (EEW) in a liquid. The fragments were classified into two types: quasi-two-dimensional (2D) samples, the characteristic size of which, d*, was greater than (or equal to) the tube wall thickness; and three-dimensional (3D) samples of the size d* < d. The study of the influence of the initial sample porosity indicates a direct effect on the formation of 3D fragments, and the distribution of the porosity is described by the power law function with an exponent differing from that of the 3D fragments size distribution. According to the scenario, the initial defects (pores) provide conditions for multi-site fracture of ceramics under high-rate loading. The instability of fast crack propagation leads to micro-branching, which creates conditions for the formation of the 3D objects. The 3D fragments size distribution is described by the power law, which corresponds to the micro-branch distribution.

We have studied, both experimentally and theoretically, the mechanisms of plastic shear localization during the dynamic deformation (adiabatic shear band formation) of metals. Instability mechanisms are frequently associated with collective effects in microdefect ensembles in spatially localized regions. Infrared in-situ scanning of instability regions and further investigation of a dislocation substructure confirm that non-equilibrium transitions play a key role in defect ensembles during the evolution of a localized plastic flow. The use of equations reflecting a relationship between non-equilibrium transitions and plastic flow has made it possible to perform simulations for plastic shear localization.

The behavior of specimens dynamically loaded during split Hopkinson (Kolsky) bar tests in a regime close to simple shear conditions was studied. The lateral surface of the specimens was investigated in-situ using a high-speed infrared camera CEDIP Silver 450M. The temperature field distribution obtained at different time allowed one to trace the evolution of plastic strain localization. The process of target perforation involving plug formation and ejection was examined using a high-speed infrared camera and a VISAR velocity measurement system. The microstructure of tested specimens was analyzed using an optical interferometer-profiler and a scanning electron microscope. The development of plastic shear instability regions has been simulated numerically.

The behavior of specimens dynamically loaded during the split Hopkinson (Kolsky) bar tests in a regime close to simple shear conditions was studied. The lateral surface of the specimens was investigated in a real-time mode with the aid of a high-speed infra-red camera CEDIP Silver 450M. The temperature field distribution obtained at different time made it possible to trace the evolution of plastic strain localization. The process of target perforation involving plug formation and ejection was examined using a high-speed infra-red camera and a VISAR velocity measurement system. The microstructure of tested specimens was analyzed using an optical interferometer-profilometer and a scanning electron microscope. The development of plastic shear instability regions has been simulated numerically.

Fragmentation statistics of shocked Al2O3 tubular specimens are studied. The parameter of the tube k = d/r2 is less than unity, where d is thickness of the tube, r2 is inner radius of the tube. Samples were fractured under electro-explosion shock wave loads initiated in the liquid. The mass of collected fragments in the liquid was about 98%. The mass of fragments was estimated by the “weighting” and “photography” techniques. Fragment distributions N(m) with mass greater than a specified value m were analyzed depending on specific energy of pulse load. It has been established that the inflection point in the distribution is shifted toward smaller scale with an increasing specific energy w. The analysis of fragmentation statistics revealed power and exponential laws depending on the value of k and fragment dimension (2D and 3D fragments). The power distributions are characteristic for small fragments (3D-statistics, mfrag < mmean and d* < d, where d* is characteristic fragment size) and exponential 2D-stati...

Plastic strain localization and fracture of dynamically loaded metallic samples occurred during plug formation are investigated. These processes are closely related to the instability of plastic flow and can be attributed to structural-scaling transitions in mesodefect ensembles. The multiscale nature of defect structure allows one to use the fractal concept for quantitative analysis of both the fracture surface and the inner structure of deformed material. The scaling properties of fracture surfaces are established in terms of the roughness index (Hurst exponent) as the characteristics of strain localization and fracture.

The experimental study of material responses in a wide range of loading rate reveals some insight into dynamic failure and shows the linkage of solid behavior with the evolution of mesoscopic defects such as microcracks and microshears. This situation is strongly connected to dynamic and shock wave loading, when the time for mesodefect evolution, across different length-scales approaches the characteristic loading times. Taking into account the nature of plastic deformation and failure the key problems are related to the statistics and thermodynamics of the mesoscopic defects. This is revealed in the features of non-equilibrium systems with “slow dynamics”. “Slow dynamics” is the consequence of collective interactions between mesodefect modes with slow spatial-temporal response in comparison to the acoustic properties of the material (elastic wave propagation). The existence of these slow modes dominates the failure in dynamically loaded and shocked materials. The original study was conducted to support theoretical results and constitutive relations, which describe a different scenario of damage-failure transition with a self-organized criticality in mesodefect behavior — the structural-scaling transition.

The effects of loading intensity and material structure on statistical regularities of fragmentation were studied. The material under investigation is zirconia-based ceramics. The samples with different pore structure (10%, 20%, 30%, 45%, 60% - the porosity of the powder used for ceramic sample sintering) were tested. The experimental data on dynamical fragmentation of ZrO2 ceramics allowed us to construct the fragment size distribution (spatial scaling) and the distribution of time interval between fractoluminiscense pulses (time scaling). The power law exponent of spatial scaling depends on ceramics porosity and intensity of loading, which has a considerable influence on the power law exponent for samples with highest porosity (60%). Two types of the distribution function for time interval were observed. For ceramics of low porosity (less than 60%) the distribution is fitted by two power laws with different exponents, and the distribution of time intervals for ceramics of highest porosity (60%) obeys one power law. An increase in porosity leads to the growth of the number of single fracture events (the number of middle and short intervals), as a consequence of missing the second power law exponent. Statistics of pore systems in two samples with 20% and 60% porosity was studied using X-ray Computed Tomography (CT). Analyzing more than a thousand of cross section images for every sample, we get a cumulative pore area distribution, and a relationship between area and perimeter. The best fitting for pore area distribution are: 1) two power laws for sample with highest porosity (60%); 2) double exponential law for low porosity (20%). The area – perimeter relation satisfies a power law.

Fragmentation phenomenon is the breaking of solids into separate fragments under quasi-static, impact or explosive loading. The present investigation was conducted to examine experimentally the fragmentation of brittle materials: 1) glass fragmentation under quasi-static loading; 2) quartz fragmentation under dynamic loading; 3) ZrO2 ceramic fragmentation using Split Hopkinson Bar techniques; 4) impact fragmentation of synthetic mineral alloys (syminals).

The developed statistical model of solid with mesoscopic defects allowed the formulation of phenomenological model in terms of two independent variables—the defect density tensor and structural scaling parameter and the simulation of shock wave propagation in the linkage with structural relaxation phenomena. It was established the link of the Hugoniot elastic limit with kinetics of structural transition (mathematically related to the defect density tensor) in the structural metastability area, that has generally thermally‐activated character. The development of plastic front is described as the consequence of self‐consistent structural (orientation) transition in microshear ensemble that is realized due to the kinetics of structural scaling parameter. The present investigation was directed to describing of the failure phenomena. Two cases are discussed (quasi‐brittle and elastic‐plastic behavior).

The application of statistical theory allows the development of new description of critical phenomena—structural‐scaling transitions. These can be classified as a specific form of self‐organized criticality in mesodefect ensembles (microcracks, microshears). The phenomenology developed explains different stages of the damage kinetics and self‐similarity of damage localization, related to the generation of collective modes of defect response in a number of different damage‐failure transitions. Dynamic, shock wave experiments and structural studies support the role of these modes in material response in a wide range of load intensity and highlight the linkage of different mechanisms of dynamic crack propagation, fragmentation statistics and the resonance nature of failure wave generation and propagation.