Numerical simulation of mechanical behaviour and prediction of effective properties of metal matrix composites with consideration for structural evolution under shock wave loading

Mechanical behaviour of stochastic metal-ceramic composite materials under shock wave loading was numerically simulated on mesoscopic scale level. Deformation of mesoscopic volumes of composites whose structure consisted of a metal matrix and randomly distributed ceramic inclusions was simulated. The results of numerical simulation were used for numerical evaluation of effective elastic and strength properties of metal-ceramic materials with different values of volume concentration of ceramic inclusions. The values of the effective mechanical characteristics of investigated materials were obtained, and the character of the dependence of the effective elastic and strength properties on the structure of composites was determined. It is shown that the dependence of the values of the effective elastic moduli on the volume concentration of ceramic inclusions is nonlinear and monotonically increasing. The values of the effective elastic limits increase with increasing concentration of the inclusions, however, for the considered composites, this dependence is not monotonic

Numerical investigation of effective mechanical properties of metal-ceramic composites with reinforcing inclusions of different shapes under intensive dynamic impacts

In the present paper, the results of numerical simulation of high-rate deformation of stochastic metal-ceramic composite materials Al–50% B4C, Al–50% SiC, and Al–50% Al2O3 at the mesoscopic scale level under loading by a plane shock wave are presented. Deformation of the mesoscopic volume of a composite, whose structure consists of the aluminum matrix and randomly distributed reinforcing ceramic inclusions, is numerically simulated. The results of the numerical simulation are used for the investigation of special features of the mechanical behavior at the mesoscopic scale level under shock-wave loading and for the numerical evaluation of effective elastic and strength properties of metal-ceramic composites with reinforcing ceramic inclusions of different shapes. Values of effective sound velocities, elastic moduli and elastic limits of investigated materials are obtained, and the character of the dependence of the effective elastic and strength properties on the structure parameters of composites is determined. The simulation results show that values of effective mechanical characteristics weakly depend on the shape of reinforcing inclusions and mainly are defined by their volume concentration

A new form of Spiraea flexuosa from Western Sayan

The issues of studying biological diversity, including at the intraspecific level, are among the most important in biology. The form diversity of woody plants is far from fully revealed. Most often, new forms are identified by crown habit, size and shape of leaf blades and their pubescence, size and color of flowers. Much less attention is paid to the color of the leaves. In the course of fieldwork in 2021, on the Kurtushibinsky Ridge, which is part of the Western Sayan system, in the protected zone of the Sayano-Shushensky State Natural Biosphere Reserve near the village of Bazaga, the authors found a small population of spiraea flexuous (Spiraea flexuosa Fisch ex Cambess.) with bright, carmine-red leaves. Previously, no forms were noted in spiraea flexuous. However, for the closely related species S. сhamaedryfolia, which some authors previously considered a synonym for spiraea flexuous, 3 forms were described: f. crataegifolia Zhl., f. transiens Zhl. and f. stenophylla Zhl. They differed only in the shape and size of the leaf blades. Forms with leaves other than typical green have not been described before. The found form, being introduced into the arboretum of the Central Siberian Botanical Garden of the Siberian Branch of the Russian Academy of Sciences, retained its characteristics. In accordance with the Code of Botanical Nomenclature, she was given the name – Spiraea flexuosa Fisch ex Cambess., f. atropurpurea Karakulov et Shaulo. The red-leaved form of spiraea flexuousis highly decorative and can be successfully used in landscaping settlements in Siberia

Numerical simulation of mechanical behaviour and prediction of effective properties of metal matrix composites with consideration for structural evolution under shock wave loading

Mechanical behaviour of stochastic metal-ceramic composite materials under shock wave loading was numerically simulated on mesoscopic scale level. Deformation of mesoscopic volumes of composites whose structure consisted of a metal matrix and randomly distributed ceramic inclusions was simulated. The results of numerical simulation were used for numerical evaluation of effective elastic and strength properties of metal-ceramic materials with different values of volume concentration of ceramic inclusions. The values of the effective mechanical characteristics of investigated materials were obtained, and the character of the dependence of the effective elastic and strength properties on the structure of composites was determined. It is shown that the dependence of the values of the effective elastic moduli on the volume concentration of ceramic inclusions is nonlinear and monotonically increasing. The values of the effective elastic limits increase with increasing concentration of the inclusions, however, for the considered composites, this dependence is not monotonic

Numerical investigation of effective mechanical properties of metal-ceramic composites with reinforcing inclusions of different shapes under intensive dynamic impacts

In the present paper, the results of numerical simulation of high-rate deformation of stochastic metal-ceramic composite materials Al–50% B4C, Al–50% SiC, and Al–50% Al2O3 at the mesoscopic scale level under loading by a plane shock wave are presented. Deformation of the mesoscopic volume of a composite, whose structure consists of the aluminum matrix and randomly distributed reinforcing ceramic inclusions, is numerically simulated. The results of the numerical simulation are used for the investigation of special features of the mechanical behavior at the mesoscopic scale level under shock-wave loading and for the numerical evaluation of effective elastic and strength properties of metal-ceramic composites with reinforcing ceramic inclusions of different shapes. Values of effective sound velocities, elastic moduli and elastic limits of investigated materials are obtained, and the character of the dependence of the effective elastic and strength properties on the structure parameters of composites is determined. The simulation results show that values of effective mechanical characteristics weakly depend on the shape of reinforcing inclusions and mainly are defined by their volume concentration

Numerical simulation of mechanical behaviour and prediction of effective properties of metal matrix composites with consideration for structural evolution under shock wave loading

Mechanical behaviour of stochastic metal-ceramic composite materials under shock wave loading was numerically simulated on mesoscopic scale level. Deformation of mesoscopic volumes of composites whose structure consisted of a metal matrix and randomly distributed ceramic inclusions was simulated. The results of numerical simulation were used for numerical evaluation of effective elastic and strength properties of metal-ceramic materials with different values of volume concentration of ceramic inclusions. The values of the effective mechanical characteristics of investigated materials were obtained, and the character of the dependence of the effective elastic and strength properties on the structure of composites was determined. It is shown that the dependence of the values of the effective elastic moduli on the volume concentration of ceramic inclusions is nonlinear and monotonically increasing. The values of the effective elastic limits increase with increasing concentration of the inclusions, however, for the considered composites, this dependence is not monotonic

On the finding of Ribes diacanthum Pall. in the south of Republic of Khakassia

Finding of Ribes diacanthum Pall. in Khakassia clarifies the western border of distribution area of this species. Location is probably of a relict character.</p