Abstract. This paper presents the study of the evolution in situ of distribution of local deformations in near-surface layers in pads made of carbon lamellas under strain deformation. The specimens were produced from two face-to-face docked steel pads 120×40×4 mm and two carbon lamellas FibARM Lamel 120×40×1,2 mm joint using the adhesion 'FibARM Resin Laminate+". The strain tests were performed using the "INSTRON 3386" test bed with a maximum tension of 100 кN (10,19 тs). Optical measurement system VIC-3D was used to identify the evolution of deformations distribution in the near-surface layers. The VIC-3D system allowed obtaining the images that reflect the evolution of distribution of relative deformations iso-fields under different loads. In situ experimental research was conducted focused on strain deformations in specimens made of a layered composite: metal/adhesive/carbon lamella. A crack in the specimen was modeled, which allowed determining that with a growth of the overall deformation there develops an evolution of special structural elements from chaotic (along the whole lamella area) to localized ones with higher deformation values in the crack region. It was established that at higher levels of overall deformation in the crack region on the carbon lamella surface, the maximum deformation region with one extremum is divided by a narrow line of low deformation into two parts along the joint of steel plates. A limit deformation is identified.

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Abstract. The paper presents results of the research on strength of concrete slabs reinforced with steel fiber and tested under a high velocity impact. Mathematical models are proposed to describe the behavior of continua with a complex structure with consideration of porosity, non-elastic effects, phase transformations and dynamic destructions of friable and plastic materials under shock wave impact. The models that describe the behavior of structural materials were designed in the RANET-3 CAD software system. This allowed solving the tasks of hit and explosion in the full threedimensional statement using finite elements method modified for dynamic problems. The research results demonstrate the validity of the proposed mathematical model to calculate stress-strain state and fracture of layered fiber concrete structures under high velocity impact caused by blast wave.

The results of the investigation of deformation during axial compression of a steel-concrete round column with dimensions of 1000×102 mm on the testing machine Universal Testing Machine 4500 using a digital optical system Vic-3D are presented. The patterns of the evolution of strain field distributions on the surface of the steel shell of the column are obtained. A deformation diagram indicating the transition stages of elastic strains to inelastic ones is constructed. A jump-like dependence of the Poisson’s ratio on the longitudinal relative strain of the steel concrete column during deformation of the steel concrete column is established. This phenomenon is explained under the assumption that the deformation process involves redistribution of the forces (deformations) among the components of the composite system at the stage of joint operation before separation of the steel/concrete media and operation of concrete beyond elastic strain under conditions of volumetric compression.

Исследование динамических параметров на основе модального анализа дает представление о состоянии технической системы с учетом воздействий внешних факторов и собственных свойств. Цель работы: на основе экспериментальных исследований и численных расчетов установить зависимость динамических параметров железобетонных колонн каркаса от возрастающих напряжений сжатия. Динамические характеристики здания в виде частот собственных колебаний колонн получены с применением дальномерного виброметра RSV-150. Модальный анализ поведения модели железобетонной колонны при сжатии произведен с использованием программного комплекса ANSYS. По результатам проведѐнных натурных и численных исследований получены диаграммы зависимости частоты собственных колебаний железобетонных колонн от величины сжимающих напряжений. Анализ полученных диаграмм показал, что экспериментально полученные кривые характеризуются ростом частоты собственных колебаний железобетонных колонн при увеличении напряжений сжатия, в отличие от результатов численного эксперимента, демонстрирующих снижение частоты. Полученные результаты могут быть применены при оценке технического состояния сжатых элементов строительных конструкций на основе модального анализа. В статье представлены результаты экспериментальных и численных исследований динамических параметров сжатых железобетонных колонн каркаса. Получены зависимости влияния величины сжимающих напряжений на частоту собственных колебаний железобетонных колонн каркаса. Ключевые слова: железобетонный каркас; колонна; частота собственных колебаний; напряжения сжатия; граничные условия.