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Author

V. A. Krasnoveikin

Other affiliations: Tomsk State University
Bio: V. A. Krasnoveikin is an academic researcher from Russian Academy of Sciences. The author has contributed to research in topics: Severe plastic deformation & Ultimate tensile strength. The author has an hindex of 5, co-authored 16 publications receiving 82 citations. Previous affiliations of V. A. Krasnoveikin include Tomsk State University.

Papers
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TL;DR: In this article, the results of investigations of physico-mechanical properties of specimens made from the structural Mg-based alloy (Russian grade Ма2-1) after SPD processing are presented.
Abstract: The results of investigations of physico-mechanical properties of specimens made from the structural Mg-based alloy (Russian grade Ма2-1) in its coarse-grained and ultrafine-grained states after SPD processing are presented. To form the ultrafine-grained structure, use was made of the method of orthogonal equal-channel angular pressing. After four passes through the die, a simultaneous increase was achieved in microhardness, yield strength, ultimate tensile strength and elongation to failure under conditions of uniaxial tensile loading.

22 citations

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TL;DR: In this article, the elastic limit and tensile strength of deformed magnesium alloys with different structures and textures were measured with the aim of finding a correlation between the spectrum of defects in the material and the resistance to deformation and fracture under quasi-static and dynamic loading conditions.
Abstract: The elastic limit and tensile strength of deformed magnesium alloys Ma2-1 with different structures and textures were measured with the aim of finding a correlation between the spectrum of defects in the material and the resistance to deformation and fracture under quasi-static and dynamic loading conditions. The studies were performed using specimens in the as-received state after high-temperature annealing and specimens subjected to equal-channel angular pressing at a temperature of 250°C. The anisotropy of strength characteristics of the material after shock compression with respect to the direction of rolling of the original alloy was investigated. It was shown that, in contrast to the quasi-static loading conditions, under the shock wave loading conditions, the elastic limit and tensile strength of the magnesium alloy Ma2-1 after equal-channel angular pressing decrease as compared to the specimens in the as-received state.

20 citations

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TL;DR: In this article, an ultrasonic spectroscopic approach to laser vibrometry applied to hybrid composite materials subjected to impact damage is described, where the meander-shaped signal for resonance stimulation was applied to enhance the detection of multi-component defects.

18 citations

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TL;DR: In this article, the effect of severe plastic deformation on the physical and mechanical properties of a light structural Al-Mg alloy was examined by equal channel angular pressing through a die with an angle of 90° between the channels to produce ultra-fine-grained structure.
Abstract: This study examines the effect of severe plastic deformation on the physical and mechanical properties of a light structural Al-Mg alloy. Severe plastic deformation has been performed by equal channel angular pressing through a die with an angle of 90° between the channels to produce ultrafine-grained structure in specimens of studied alloy. A complex investigation of the physical and mechanical properties of the processed alloy has been carried out to examine the microstructure and texture, and to measure microhardness, yield stress and ultimate tensile strength. The obtained results demonstrate high efficiency of the chosen treatment method and mode of producing a light ultrafine-grained alloy.

9 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of a severe plastic deformation achieved by groove pressing (GP) on the grain structure and mechanical properties of a rolled sheet Al-Mg alloy was investigated.
Abstract: In this article, the effect of a severe plastic deformation (SPD) achieved by groove pressing (GP) on the grain structure and mechanical properties of a rolled sheet Al-Mg alloy was investigated. The study of the microstructure of the samples before and after processing was carried out by means of electron backscattered diffraction (EBSD). The mechanical properties of the samples were experimentally studied under uniaxial tension in quasi-static conditions, and microhardness testing was implemented. It was found that the conventional yield strength and ultimate tensile strength increase by the factor of 1.4 and 1.5, respectively; and the microhardness increases by approximately 2.7 times after four machining sequences of the rolled sheet alloy. A bimodal grain structure, consisting of two grain types with particular features, is formed in the samples after four machining sequences of GP.

8 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a low-rank one-step wave extrapolation approach using complex-valued lowrank decomposition is proposed to approximate the mixed-domain space-wavenumber wave extension symbol, which is more flexible than a real-valued phase function of two-step schemes.
Abstract: Reverse time migration (RTM) relies on accurate wave extrapolation engines to image complex subsurface structures. To construct such operators with high efficiency and numerical stability, we have developed a one-step wave extrapolation approach using complex-valued low-rank decomposition to approximate the mixed-domain space-wavenumber wave extrapolation symbol. The low-rank one-step method involves a complex-valued phase function, which is more flexible than a real-valued phase function of two-step schemes, and thus it is capable of modeling a wider variety of dispersion relations. Two novel designs of the phase function leads to the desired properties in wave extrapolation. First, for wave propagation in inhomogeneous media, including a velocity gradient term assures a more accurate phase behavior, particularly when the velocity variations are large. Second, an absorbing boundary condition, which is propagation-direction-dependent, can be incorporated into the phase function as an anisotropic a...

58 citations

Journal ArticleDOI
TL;DR: In this paper, the forward-propagated source wavefield and the residual wavefield were cross-correlated to calculate the gradient in full waveform inversion (FWI).
Abstract: The calculation of the gradient in full-waveform inversion (FWI) usually involves crosscorrelating the forward-propagated source wavefield and the back-propagated data residual wavefield at...

47 citations

Journal ArticleDOI
TL;DR: In this paper, a general recipe for constructing n-parameter family of conserved second rank tensors for higher derivative 3D vector field models with the field equation operator being a polynomial of the Chern-Simons operator is provided.
Abstract: We consider the class of higher derivative 3d vector field models with the field equation operator being a polynomial of the Chern–Simons operator. For the nth-order theory of this type, we provide a general recipe for constructing n-parameter family of conserved second rank tensors. The family includes the canonical energy-momentum tensor, which is unbounded, while there are bounded conserved tensors that provide classical stability of the system for certain combinations of the parameters in the Lagrangian. We also demonstrate the examples of consistent interactions which are compatible with the requirement of stability.

32 citations

Journal ArticleDOI
TL;DR: In this article, a laser-launched micro-flyer was used for spall strength measurement of AZ31B Mg alloy thin foils, a material system with potential applications as a lightweight protection material.
Abstract: We describe a laser-launched micro-flyer apparatus designed for spall strength measurement. The launcher uses a single pulse from a pulsed laser that is stretched in time to nominally 20 nanoseconds using an optical ring cavity, while inexpensive multi-lens arrays are used to spatially homogenize the beam. The velocimetry technique that we developed for the experiment provides the required sub-nanosecond time resolution. We demonstrate the capability of the apparatus to interrogate the spall strength of AZ31B Mg alloy thin foils, a material system with potential applications as a lightweight protection material. Numerical simulations and fractography are very useful to determine the quality of the experimental data and help to interpret our results. The simulations and fractography analyses of the experiments suggest that the short shock pulse duration in the experiment causes incipient spallation. The short pulse also likely introduces stochasticity to the measured spall strength through limited activation of failure mechanisms within the samples. The shocked AZ31B Mg alloy has spall strengths that are greater than previously reported figures for fine grained Mg alloys, likely because the laser based system achieves higher strain rates than in prior work on this material.

30 citations

Journal ArticleDOI
TL;DR: The main conclusion was that the effectiveness of measurements strongly depends on the chosen wave frequency value, and the influence of an excitation frequency value on the obtained visualizations was considered experimentally and numerically in the wide range for a single defect.
Abstract: Structural adhesive joints have numerous applications in many fields of industry. The gradual deterioration of adhesive material over time causes a possibility of unexpected failure and the need for non-destructive testing of existing joints. The Lamb wave propagation method is one of the most promising techniques for the damage identification of such connections. The aim of this study was experimental and numerical research on the effects of the wave frequency on damage identification in a single-lap adhesive joint of steel plates. The ultrasonic waves were excited at one point of an analyzed specimen and then measured in a certain area of the joint. The recorded wave velocity signals were processed by the way of a root mean square (RMS) calculation, giving the actual position and geometry of defects. In addition to the visual assessment of damage maps, a statistical analysis was conducted. The influence of an excitation frequency value on the obtained visualizations was considered experimentally and numerically in the wide range for a single defect. Supplementary finite element method (FEM) calculations were performed for three additional damage variants. The results revealed some limitations of the proposed method. The main conclusion was that the effectiveness of measurements strongly depends on the chosen wave frequency value.

27 citations