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Ключевые слова: strength

Properties of Verkhnealkunsky deposit mudstones used as raw materials to manufacture clinker tiles

https://doi.org/10.58224/2618-7183-2024-7-3-7
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Аннотация
The article writes about the development of mudstone-based raw material compositions used to manufacture clinker tiles with improved physical and technical properties. Clinker tiles are one of the popular roofing materials. Compared to other roofing covering options, clinker tiles have higher strength, more resistance to aggressive environments, and better aesthetic characteristics. Clinker tile production is relevant due to the fact that currently architects and building constructors are showing great interest in such an elite roofing material, but due to the economic situation, this roofing material is no longer imported to Russia, with an empty market niche having been formed. Many Russian brick factories are planning to install additional technological lines to manufacture ceramic tiles, but the current demand is to produce clinker tiles. The main unresolved issue concerns raw materials since traditional raw materials – loams and clays – are very rarely suitable for the production of low-temperature sintering clinker tiles. Having studied a large amount of academic literature and carried out the necessary laboratory studies, the authors of this article, under the guidance of the Chair of the Construction Materials Department, Prof. V.D. Kotlyar, pay serious attention to such raw materials as mudstones from the Verkhnealkunsky deposit of the Russian Republic of Ingushetia. The article provides a general description of mudstones, including their chemical and mineral composition as well as their structural features for the production of clinker tiles. It has been experimentally established that the degree of their grinding has a significant influence on technological properties of both mudstones and the end products. Based on raw material mixtures with a grain composition of 0-0.16 and 0-0.08 mm, it is possible to manufacture clinker tiles using the extrusion molding method without introducing corrective additives. The data obtained will make it possible to develop technological regulations to manufacture clinker tiles based on Verkhnealkunsky deposit mudstones.
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Optimization of Rectangular and Box Sections in Oblique Bending and Eccentric Compression

https://doi.org/10.58224/2618-7183-2023-6-5-2
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Аннотация
The article presents a solution to the problem of finding the optimal ratio of the height of the cross-section to the width for a rectangular and box-shaped section in the case of oblique bending and eccentric compression. Optimization is performed according to the strength criterion, and for the case of oblique bending of a rectangular beam, a solution was also obtained from the condition of a minimum full deflection. For a rectangular section, the solution is made analytically, and for a box section, numerically using the MATLAB environment and the Optimization Toolbox package. As a numerical method of nonlinear optimization, the interior point method is used. To simplify the solution, the box section is assumed to be thin-walled, i.e. it is assumed that the wall thickness is significantly less than the height and width of the cross section. An estimate of the error of such an assumption is also performed. It has been established that in the case of oblique bending of a rectangular beam, when optimizing according to the strength criterion, the optimal ratio of the cross-sectional height to width is equal to the cotangent of the angle between the force plane and the vertical axis, and when optimizing according to the rigidity criterion, it is the square root of the cotangent of this angle. In the case of eccentric compression of a rectangular beam with eccentricities in two planes, the optimal ratio of the height of the cross section to the width is equal to the ratio of the eccentricity along the vertical and horizontal axes. For a box-shaped section, graphs of the change in optimal parameters depending on the angle between the force plane and the vertical axis in the case of oblique bending, as well as depending on the ratio of eccentricities along the axes in the case of eccentric compression, are plotted.
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