The article discusses the general characteristics of the deformation of concrete under repeated cyclic loads of compressive stresses observed in the experiments executed by the authors, as well as domestic and foreign researchers. Based on experimental data of fixed and variable levels of stress, limits have been defined for reference points of stabilization of strains and stresses. The plotted stabilization diagram outlines the accumulated deformation with the increase of the number of cycles and shows the stress level above which the concrete fails after a finite number of cycles. The total deformation of concrete in the initial system of coordinates is determined by summing up the incremental strain of each cycle calculated in the new system of coordinates. This technique is used to determine the number of cycles until the stabilization of the deformation at low stress levels and the number of cycles until the failure of concrete at high levels of stress.

Рассмотрены циклы с разными величинами максимальных напряжений, в т.ч. близких к предельным значениям с учетом дилатации бетона. Остаточные деформации при разгрузке определены в приращениях напряжений и деформаций лучевым методом. Установлена связь между начальными модулями упругости бетона и модулем деформаций при разгрузке. Разработаны аналитические зависимости определения величин остаточных деформаций. Ключевые слова: осевые деформации, поперечные деформации, объемные деформации, напряжения сжатия, лучевой метод, деформирование бетона, бетон.

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The possibility to simultaneously determine the thickness and the electrical conductivity of thin semiconductor layer and the mobility of its free charge carriers has been shown. The semiconductor layer plays a role of the irregularity in the one-dimensional waveguide photonic crystals. The results of the determination of highly doped semiconductor epitaxial layer parameters by the inverse problem solving using reflection and transmission spectra in microwave band are presented.

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