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A new approach is proposed for description of autowave processes responsible for plastic deformation localization in metals and alloys. It is postulated that to a localized flow autowave there corresponds a quasi-particle. The characteristics of the quasi-particle have been determined. The above postulate leads to a number of consequences and quantitative assessments that are considered herein. A direct relationship has been established between the processes involved in the deformation on a macro- and a microscale level. [ABSTRACT FROM AUTHOR]

The results of high-speed laser welding of AA5083 aluminum alloy are obtained. It is shown that at high welding speed the strength of the welded joint was 93% of the base metal strength. Electrochemical corrosion tests were carried out in order to establish the places of softening of the welded joint. It is shown that the fusion zone of the weld metal with the base metal is mostly exposed to pitting corrosion. The parameters of the corrosion process have been determined. The calculations showed an average decrease in the corrosion resistance of the weld compared to the base metal. The analysis suggested that this approach in welding is reasonable and applicable to manufacturing processes. [ABSTRACT FROM AUTHOR]

Modern materials science requires extensive development of parallel computing algorithms on supercomputers to solve a wide range of fundamental and applied problems at the atomistic level. The accumulation of new results, along with trivial experimental data and theoretical models, is facilitated by a number of software packages developed for this purpose. The main characteristics of plastic deformation in the case of poly- and nanocrystals of magnesium were calculated using the method of molecular dynamics on the URAN supercomputer (Ural branch of the Russian Academy of Sciences). Stress–strain curves for magnesium nanocrystals under high-speed deformation are constructed. The results are compared with experimental data. Various dislocation structures responsible for different levels of strength and plasticity of the nanocrystals under consideration are given. [ABSTRACT FROM AUTHOR]

The article presents the results of solving the model problem of deformation of a spherical body of a single-crystal with cubic symmetry of properties (titanium nickelide) under the action of a comprehensive compression pulse. The approach applied makes it possible to divide the elastic deformation energy into the energy of volume change and the energy of shape change for materials with cubic symmetry of properties. To solve the problem, various mathematical models were used to take into account the anisotropy of elastic properties in single crystals with cubic symmetry of properties. Their differences are determined by the relationships between uniform volumetric deformation and internal pressure. The choice of the model is determined depending on the orientation of the directions of the axes of the computational coordinate system relative to the directions of the main crystallographic axes of the single-crystal. The effect of the use of various mathematical models on the accuracy of the solutions obtained is shown. [ABSTRACT FROM AUTHOR]

The inhibitory activity of high molecular oil fractions is investigated by the method of microcalorimetry. The model reaction of initiated cumene oxidation is used to establish the effect of high molecular oil fractions isolated by different methods on the radical reaction. The predominant mechanism of inhibition is a decrease in the oxidation rate of the model reaction. For two asphaltene samples, a pronounced induction period is recorded and the inhibition rate constants are calculated. They have characteristic of oil systems k7 = (6.5–26) × 103 values l/mol s. Some of the samples under study exhibit an unconventional initiating effect on the model reaction of radical oxidation of cumene, which is due to the decomposition of thermolabile structural fragments of asphaltene macromolecules. [ABSTRACT FROM AUTHOR]

A bridged crack model is used to evaluate the effectiveness of cracks self-healing. During the self-healing process the following stages should be analyzed: 1) flaws/cracks formation and growth under external loading; 2) activation of self-healing mechanisms; 3) healing of flaws/cracks with partial or complete restoration of bonds between cracks surfaces. The kinetic model is used to estimate the formation time of the crack bridged zone. The decreasing of the stress intensity factors is considered as the main characteristic of a crack self-healing efficiency. [ABSTRACT FROM AUTHOR]

In this work, a comparative analysis of the Mg-Mn-Ce system magnesium alloy grain structure is presented for two states: as-received condition and after processing by groove pressing method. It was found that three cycles of groove pressing at sheet-shaped samples lead to the formation of the grain structure with equiaxial shaped grains and uni-modal distribution. In this case, the grain diameter after processing is refined 3 times. Due to this, a microstructure with a 2 µm average grain size is formed in the sample. A combination of structural and texture changes leads to improved mechanical properties. This allows getting semi-finished products with improved functional properties. [ABSTRACT FROM AUTHOR]

By the method of electron beam additive manufacturing with simultaneous supply of steel and copper wire filaments, the bimetal sample Fe-Cu was produced. The simultaneous feed of filaments allowed to form a gradient transition from the steel part of the stainless steel 304 to the copper part of the C11000. The macrostructural study of gradient transition showed the presence of heterogeneous distribution of steel and copper particles. The microstructural study revealed that the Fe-matrix alloyed with Cr and Ni forms copper particles ranging in size from 130 nm to 2.3 µm. Interphase boundaries are sharp without transition areas. In some areas of the sample, a moire contrast of up to 200 nm wide can be observed around the copper particle. The copper particles have the regular spherical shape, which is due to the force acting on the length of the phase contact to reduce the surface to a minimum under interphase tension. This is evidence that during crystallization of austenite copper was in a liquid condition and had droplet shapes. [ABSTRACT FROM AUTHOR]

A study of the mechanical properties and mechanical behavior characteristics during quasi-static tensile tests was carried out for a microstructural Mg-Mn-Ce system magnesium alloy obtained by cyclic groove pressing in the presented experimental work. The material average grain size refining from 9 to 2.5 µm led to increasing of the yield strength by 30%, and the ultimate strength by 17%. Structural changes also contribute to the activation of additional slip systems, which improves the ultimate strain to failure. [ABSTRACT FROM AUTHOR]

This paper analyzes the possibility to control properties of carbon black filled rubbers suitable for the production of positive temperature coefficient thermistors through properties and characteristics of an electrically conductive constituent. The following functional properties of positive temperature coefficient thermistors are considered: temperature coefficient of resistance, the spread of volume electrical resistance values during cooling after heating in relation to initial values of resistance (variation factor). Experiments prove that the electrically conductive constituent influences the considered properties. It is shown that it is possible to select the specific filler modification which provides the consistent pattern required for positive temperature coefficient thermistors: an increase of temperature coefficient of resistance, a decrease of variation factor. The carbon black surface modification compliant to physical principles of self-regulating ability is proposed according to the results of the conducted research. Interaction of carbon black particles with each other should be weaker than the interaction of carbon black particles with particles of rubber. Obtained results reveal that performed modifications of a carbon black surface can enable the properties of positive temperature coefficient thermistors when the range of volume electrical resistance becomes wider. It is concluded that modifications of a carbon black surface can be evaluated using the ratio of nonlinearity of the current-voltage characteristics of material. [ABSTRACT FROM AUTHOR]

The numerical scratching of titanium substrates with coatings based on the Ti-Al-Ta-N and Ti-Al-Ta-N systems is in the focus of the paper. In the case of Ti-Al-N coating, 25% of Ti atoms in the cubic lattice of TiN were randomly replaced by Al atoms. Four-component coating was set as Ti31Al33Ta36N with random distribution of Ta and Al. The studies were carried out using the molecular dynamics method. It was shown that for the Ti75Al25N coating the number of atoms with packaging different from the original is much larger than for the sample with the Ti31Al33Ta36N coating. Moreover the number of atoms with a local configuration different from the initial one in the sample with the ternary coating penetrates deeper into the bulk of the titanium substrate. The results of computer simulations correlate well with available data of experimental studies. [ABSTRACT FROM AUTHOR]

In this work, the study of the regularities of shear deformation in the bulk of fcc single crystals was carried out on the basis of molecular dynamics modeling. The deformation (010) of single crystals in the form of a tetragonal prism with lateral faces {101} and {100} with different ratios of the sample width to its height has been studied. Modeling has shown that the sample vertices are the preferred sites for shear initiation. It was found that the formation of deformation domains and the interaction of shear planes are due to the geometry of shear planes in the bulk of the single crystal: their location relative to the base stress concentrators and their orientation relative to the lateral faces. [ABSTRACT FROM AUTHOR]

The paper investigates the influence of an electrically conductive constituent on the behavior of carbon black filled polymers under compressive deformation. Parameters of electrical conductivity and compressive deformation are estimated in this research. It is found out that the influence of carbon on such parameters depends on the amount of applied load. Differences in the influence of an electrically conductive constituent on mechanical, electrical, and physical properties of filled polymers are proven experimentally. It is demonstrated that electrical conductivity is affected more than compressive deformation. The revealed behavior is concluded to be related to relaxation processes and electrically conductive constituent dispersion patterns in filled polymers. Recommendations on the selection of the electrically-conductive constituent for resistive composite polymers under a condition of compressive deformation are elaborated using the results of the conducted research. [ABSTRACT FROM AUTHOR]

Statistically based model of the DNA ensemble evolution allowed the formulation of mechanobiological approach linking the open complex dynamics and different scenarios of gene expression related to normal and cancerous cell behavior. It was shown the correspondence of open complex dynamics to a specific type of criticality in mesodefects ensemble (the structural-scaling transition) in the presence of the mesoscopic potential associated with the epigenetic landscape. The role of open complexes is similar to the mesoscopic defects and provides the cell plasticity or the cell fragility depending on the structural susceptibility of the cytoskeleton structure and the types of collective modes of defects (open complexes). These modes are responsible for the DNA transformation leading to the natural cycle of gene expression and the cell division or spontaneous cell fragmentation with anomalous proliferation as the cancer precursor. The WTMM analysis of the phase thickness fluctuations after the Coherent Phase Microscopy (CPM) of living cells shows the log-normal and power law statistics for normal and cancerous scenarios that are linked to multi- and monofractal dynamics of open complexes. [ABSTRACT FROM AUTHOR]

This work shows the results of the numerical investigation of the stress-state and the fracture of zirconia ceramic specimens under Brazilian test conditions. To account for the heterogeneous structure of the specimens in the simulation two different statistical computer models were considered. In the models, a random scatter of the shear strength amounts to ±5% and ±50%. The behavior of zirconia ceramic specimens is described by the Drucker–Prager model with non-associated plastic flow rule. It is shown that the failure in the specimen with scatter 5% occurs at higher stresses compared to the specimen with scatter 50%. Also, it is noted that the crack propagates more quickly in the specimen with scatter 5% and the bigger part of the specimen is fractured. The cracks branching and material fragmentation are observed. The numerical simulation showed good agreement with the experiment. [ABSTRACT FROM AUTHOR]

The paper is concerned with a relaxation model of a loaded elastic-plastic medium with dislocation kinetics of plastic shear, which can be assigned to microscopic models. All model parameters are determined from independent experiments on evolution of a dislocation continuum during loading of macroscopic specimens. The model provides an adequate description of the dependence of the observed dynamic effects of macroscopic response of materials on the strain rate: the upper and lower yield points (sharp yield point, yield plateau), subsequent strain hardening, cyclic and alternating loading, the ideal and nonideal Bauschinger effect. [ABSTRACT FROM AUTHOR]

The paper presents the recursive-search based algorithm f determining the displacements of surface patch (optical flow) to be applied on GPU utilizing the parallel computations principle. OpenCL computing language is used to implement the parallel computations algorithm which is focused on application on AMD Radeon GPUs. The results of testing of the proposed algorithm show the multiple decreases the time of displacement vector field construction while maintaining the accuracy and robustness. [ABSTRACT FROM AUTHOR]

It has been studied ceramic materials based on ZrO2. The phase composition of materials was studied by X-ray diffraction analysis. A mechanical characteristic under uniaxial compression was studied including transverse deformation which allowed calculated a Poisson's constant. It has been obtained that for sample without porosity Poisson constant equal 0.335, but for sample with 30% of porosity one can obtain sharp changes of a Poisson's constant from 0.356 up to 0.125 due to an involving to deformation process tetragonal-to-monoclinic phase transformation. It has been shown that Young modulus under compression test depends on the structural transformation and linearly depends on the amount of the tetragonal phase being converted to the monoclinic one. [ABSTRACT FROM AUTHOR]

The paper shows the features of the deformation of materials with cubic, transversely isotropic and orthotropic symmetry of properties. The formation of the "safe" stress state which ensures the absence of plastic deformations in anisotropic materials is determined by the values of bulk compression modules in the directions of each axis of the calculated coordinate system. The study of deformation processes in materials characterized by cubic symmetry of properties showed that in some directions the deformation is determined by the maximum values of the longitudinal characteristics and the minimum values of bulk compression modules. The minimum values of the bulk compression modules lead to decrease in stress in the selected direction under the conditions of volumetric deformation, or to earlier plastic deformation in comparison with other directions. By the example of solving the model problem, the features of the deformation processes in materials with cubic, transversely isotropic, and orthotropic symmetry of properties and also the formation of the "safe" stress state in them are shown. Anisotropic materials are classified according to the features of the formation of the "safe" stress state in them. [ABSTRACT FROM AUTHOR]

The paper outlines a general approach to constructing a system of mutually connected equations describing the deformation of porous fluid-saturated materials with a linear elastic skeleton. The developed approach is based on the use of the Lagrangian formalism and the principle of least action. The Lagrangian of a porous elastic fluid-saturated material is constructed in such a way that well-known equations that describe the motion of a liquid and a solid follow as limiting cases. The main advantage of the proposed formalism is the use of only standard material parameters, namely elastic moduli and volume fractions of components. Based on the obtained system of equations, a preliminary analysis of the stationary wave process in a 1D fluid-saturated medium is carried out. It is shown that three longitudinal and three transverse stationary waves with different velocities can steadily propagate in a poroelastic medium. [ABSTRACT FROM AUTHOR]

The article studies the morphology of the top surface of Ti-2Al-1.5Mn alloy welds produced by friction stir welding. The surface morphology directly depends on the nature of mass transfer at welding. The spacing between the transfer layers, fractal dimension of the surface, complexity of the 2D profile curve and roughness were chosen as characteristics. It was found that the spacing between the transfer layers is load-dependent, which was not previously observed. It was found that the formation of the transfer layer is complex. In particular, a transfer layer may contain up to four peaks. Technological parameters affect the height and number of peaks. The surface complexity can be determined by the fractal dimensionality or the complexity of the 2D profile curve. These methods have shown good agreement. Roughness often depended inversely on surface complexity. [ABSTRACT FROM AUTHOR]

The article is devoted to possibilities of innovation policy positioning for Russia. Key innovation instruments and innovation actors are shown. Separately the role of innovation universities is researched. Opportunities of international collaboration in the field of education, science, R&D are revealed. Recommendations for Russian national branding strategy forming are made. [ABSTRACT FROM AUTHOR]

In this work, the numerical study of yield phenomenon is addressed. The material for investigation is low-carbon 08PS steel demonstrating the yield phenomenon in simple tensile testing. Judging by the literature review, the number of papers carefully addressing the curves of dependencies of Lüders elongation and band propagation rate on parameters of mathematical model—namely, the amplitude of stress drop and strain hardening factor, is not large. This work aims at filling this gap. [ABSTRACT FROM AUTHOR]

The problem of elastic waves propagation through the interfaces which are considered as a structure elements of inhomogeneous solid is investigated. An infinitesimal thin layer is the usual model of boundary in the classical mechanics. The considered interfaces are characterized by dimensions and the physical-mechanical properties that are different from ones of the contacting solids. The models of layered and block media are used for these interfaces description. Analytical expressions for the Fresnel coefficients allowing us to find the strain components on the interface are derived. The dependences of Fresnel coefficients and strain amplitudes as functions of interface thickness and elastic properties of the contacting solids are calculated at the normal incidence of P and SV waves on the boundary. Strains features on the interface are analyzed in the frame of two considered models. [ABSTRACT FROM AUTHOR]

The problem of elastic waves propagation through the contact layer at the boundary conditions of imperfect contact is considered. Boundary conditions modeled by effective spring are used for describing the interface damages determining the imperfect contact of two elastic bodies. According to these boundary conditions the stress is continuous on an interface and the displacement vector is not continuous on the interface. Analytical expressions for the Fresnel coefficients of the contact layer and waves propagating in the layer are derived which allow us to find the intensities for reflected and refracted waves and the strain distribution in the layer. The dependences of reflected wave intensity and strain amplitudes as functions of layer thickness and elastic properties of the contacting solids are calculated and analyzed at the normal incidence wave on the boundary. [ABSTRACT FROM AUTHOR]

In this paper microseismic ambient noise analysis is based on cross-correlation of seismic noise components and cross-spectral analysis in a sliding window in time. The velocity changes were estimated at small aperture in the high frequency range (hundreds of Hz) at the section of the fault zone of the Korobkovskoye ore deposit. The analysis carried out made it possible to determine the propagation velocity and estimate coseismic velocity changes associated with ripple-fired explosion and further relaxation. [ABSTRACT FROM AUTHOR]

Along with the initial elastic and strength properties, the deformation and fracture process in rocks is significantly affected by their degradation during loading. In the present work, we supplement the Drucker–Prager model of the medium by the equation for cohesion degradation. Growing irreversible plastic deformation weakens the rock. Upon complete failure, the rock behaves like dry sand, which resists only compressive and shear loads. The model gives results that are in good agreement with field observations and physical modeling predictions. A possibility is shown of forming positive structures without setting additional boundary conditions of transverse compression for rocks like clays, sands, and soft sandstone. [ABSTRACT FROM AUTHOR]

The purpose of the study was to analyze the efficacy of the rib cage reconstruction using various implants. From 1997 to 2020, post-resection chest wall defects were restored using the original titanium nickelide implants in 84 patients with malignant neoplasms of the skin, soft tissues, ribs and sternum (sarcomas and metastases). Three time periods of using different strategies for reconstruction of thoracic cage defects were studied. The average area of the chest wall defect was 127 cm2 (40–323 cm2). Spontaneous breathing without ventilatory support was restored on the day of surgery in 27 (96.4%) cases. Thoracic cage stability was achieved in all cases. The amplitude reduction was observed in 10 (36%) and complete elimination of pathological chest wall flotation was achieved in 18 (64%) cases. Complications requiring surgical correction occurred in 3 (11%) cases. At a long-term follow-up, 10 (47.6%) patients are alive. The technique combining the use of titanium nickelid implants and complex autotissue grafts with axial type of blood supply allows chest wall cancer with extensive local spread to be successfully treated. [ABSTRACT FROM AUTHOR]

This paper numerically investigates the physical behavior of deep geological structures in the Yakutsk-Vilyui large igneous province (LIP). The geophysical data of "Craton-1980" profile was used to create the computer structures of the researched area. To analyze the inelastic deformation, the Nikolaevsky elastoplastic model was used. For investigating the geotectonic processes the strength model, which operates with cohesion and coefficient of internal friction, was adapted to the Nikolaevsky model. The depth analysis of the stress state was realized making use of the pressure and the Lode parameter. It is shown that the distribution of the Lode parameter depends on inelastic strain localization and reveals mainly the shear type of deviatoric stress. The distribution of pressure has a quasi-monotonic increasing with depth, with local disturbances caused by the shear bands in the depth layers of Earth's crust. These features are more pronounced with increasing of horizontal deformation. These results can be used by geologists to evaluate the metamorphism of rocks. [ABSTRACT FROM AUTHOR]

Transparent refractory metal-ceramic nanocomposite coatings with a high coefficient of elastic recovery and microhardness on the basis of Ni/Si-Al-N are formed on a glass substrate by the pulse magnetron deposition method. The structure-phase states were investigated by TEM, SEM. It was established that the first layer consists of Ni nanograins with a fcc crystalline lattice, the second layer is two-phase: 5-10 nm nanocrystallites of the AlN phase with the hcp crystalline lattice in amorphous matrix of the Si3N4 phase. [ABSTRACT FROM AUTHOR]

The use of the statistical analysis approach based on the application of finite mixture models and using an expectation-maximization algorithm to describe the experimental grain size distributions of HPT-nanostructured Cu-7.4Sn bronze allows us to decompose them into a set of groups of grains with sufficient accuracy. It is shown that the saturation stage after one revolution of HPT has not been reached in comparison with the sample after five revolutions. At the same time, grain structure evolution during heating depends on the initial strain state. However, the character of the evolution of both samples is similar. It is demonstrated that grains which form one of the groups are characterized by higher density of defects and enhanced energy; this decreases the volume fraction of the group during heating, with hardly changing other features. The other groups of grains seem to be formed under the influence of relaxation processes during subsequent annealing. Moreover, each subsequently formed group of grains demonstrates more intensive growth during heating, while the volume fraction of existing groups slows down until they disappear completely. [ABSTRACT FROM AUTHOR]

In the framework of the current mathematical theory of growing solids, a nonclassical mechanical model is developed to trace the evolution of elastic technological stresses in cylindrical composite pieces during the additive processes of their manufacturing by the method of multi-layer power thread winding, taking into account the structure of the material being formed and an arbitrary law of changing the thread pre-tension. Based on the proposed model, the closed analytical dependencies are constructed. [ABSTRACT FROM AUTHOR]

This paper presents a physical and mathematical model that has been developed in the framework of the approach used in the computational mechanics of materials. The model is designed to enable the study of the patterns of deformation and fracture of ceramic composites with a transformation-hardened matrix at the mesoscopic and macroscopic levels under intense dynamic loading. The influence of the loading rate on the formation of the fracture and energy dissipation fronts for composite materials based on the Al2O3-20%ZrO2 system is shown. Nonlinear effects in the considered composites under intense dynamic loading are associated with the processes of the self-organization of structural fragments at the mesoscopic level, as well as with the occurrence of martensitic phase transformations in the volumes of the strengthening particles. In this paper, specific destruction work is used as the main parameter that determines the contribution of each composite component to the destruction work. [ABSTRACT FROM AUTHOR]

The issues of computation optimization for digital signal processing operations are considered when choosing the variant of their organization in the space-time environment. The implementation of such research is based on the obtained model description of computation organization, which allows us to synthesize a variety of their variants and perform the concurrent exploration of algorithms and architectures. Methods of computation optimization obtained as a result of analyzing parameters characterizing the above model description are discussed. Using these methods in the concurrent exploration of algorithms and architectures allows you to find the best variants for computation organization. [ABSTRACT FROM AUTHOR]

In this investigation, extremal routing problems oriented to engineering applications are considered. These applications can be associated with dismantling of radioactive sources under accidents at nuclear power plants and with control of sheet cutting on CNC machines. Issues related to construction of optimal processes are investigated, including the choice of starting point, regular succession of tasks, and determination of concrete trajectories. To solve this problem, a nonstandard variant of dynamic programming is used. Precedence conditions play an important role in issues of reducing computational complexity. A theoretical procedure is implemented in the form of an algorithm and a standard program for a PC and a supercomputer. Model problems oriented to the above-mentioned engineering applications are resolved. [ABSTRACT FROM AUTHOR]

The paper presents the results of the analysis of the microstructure, mechanical and acoustic characteristics of the metal of heat power equipment after long-term operation, made of structural steels in areas of localization of plastic deformation. We study specimens made of the 0.2 C steel and the 0.12C-1Cr-1Mo-1V steel in the initial state and after operation for 219 and 360 thousand hours, respectively. Changes in the structure, mechanical and acoustic characteristics of the investigated materials are established. [ABSTRACT FROM AUTHOR]

This paper considers further development of the method for pre-design studies aimed at improving the reliability, survivability, and safety of complex mechanical systems, assembly units, and parts in accordance with the criteria of strength and resource. The Self-Organization Principle is represented as a combination of a heuristic hierarchical transdisciplinary model and metaheuristic and heuristic rules that automatically create a decision algorithm. The algorithm is determined by the object of study, by the chosen goal, and by the scientific and industrial description of the tasks. The representation of tasks as metaheuristics and heuristics allows for the use of methods and means for artificial intelligence, in particular, expert systems. Metaheuristics and heuristics are compiled by domain experts with further incorporation into the knowledge bases of the corresponding hierarchical complex of Expert Systems and Computational Modules. [ABSTRACT FROM AUTHOR]

The article provides a method for the analysis of diagnostic acoustic signals when defects are detected in composite materials. In this case, methods of the theory of fractals are used. Acoustic signals are analyzed in terms of the characteristics of multifractal spectra. The defective state of the sample shows the monofractal characteristic of the multifractal spectrum. [ABSTRACT FROM AUTHOR]

A mathematical model of a micro-heterogeneous medium is created to investigate how the strength and deformational properties of a metal are affected by its grain size. The Hall-Petch relationship is applied with consideration to the randomness of grain diameters. Relative damage is determined through the probability of fracture in microstructure elements. The macroscopic properties of the metal are calculated as they change due to micro fractures. Stress-strain curves are constructed while taking into account the changing microstructural damage at each increment of deformation. A comparison is made with experimental diagrams for copper with several average grain diameters. The purpose of this article is to create a mathematical model that takes into consideration the influence of random grain size distribution on the deformation and strength properties of metals. [ABSTRACT FROM AUTHOR]

The problem of elastic wave reflection on the free surface and on the interface with the rigid bidy is investigated in the approximation of geometrical acoustics. In both cases, the interface is considered as a structural element of an inhomogeneous body, which is characterized by dimensions and a set of physical-mechanical parameters. In the continuum mechanics the interface is generally viewed as an infinitely thin layer. Analytical expressions for the Fresnel coefficients allowing us to determine the strain components on the boundary are found at the normal incidence of P and SV waves. The dependences of the Fresnel coefficients and the strain amplitudes as functions of interface thickness and the elastic properties of contacting bodies are calculated and analyzed. [ABSTRACT FROM AUTHOR]

This paper presents the results of experimental studies on accumulation of mechanical damages in uniformly loaded identical specimens with stress concentrators made of structural CFRP laminate with load carrying stacking under varying time of stay at stressed state until fracture. The acoustic emission method is applied to the identification of damage origination and development on a real time basis. Acoustic emission impulse array processing with allowance for impulse energy provided the opportunity to enhance the quality of damage accumulation analysis and also to reveal the crucial factors, such as the stress level and time of stay at stressed state effecting coupled, unidirectional influence on the increase of the CFRP laminate damage rate. The curves of the specimen integrity degree are built with the purpose of estimating the relative level of accumulated damages depending on the levels of applied stress. [ABSTRACT FROM AUTHOR]

This paper considers the kinetics of damage from tensile plastic strain, unilaterally accumulated strain, and elastic strain converted into total damage depending on the load (durability); the analysis is based on the kinetic strain criteria and experimentation. The kinetic strain criteria are proven feasibly applicable to describing the high-temperature limit state of carbon steel, i.e. the point at which its plastic strain becomes unstable or a macrocrack appears. [ABSTRACT FROM AUTHOR]