Water Absorption Effect on the Propagation Velocity of Normal Waves in Composite Rebars

The article proposes the use of the acoustic waveguide method with normal Pochhammer waves to estimate the water absorption of composite fiberglass rebars. The results of experimental studies on the water absorption and temperature influence on the propagation velocity of rod and torsional waves in composite rebars samples with different physical and mechanical characteristics are presented. The sensitivity of the wave velocity parameter to water absorption and temperature fluctuations is estimated. The proposed acoustic waveguide method is characterized by high accuracy, reliability and efficiency.

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Experimental Studies on the Effects of Cyclic Freezing–Thawing, Salt Crystallization, and Thermal Shock on the Physical and Mechanical Characteristics of Selected Sandstones

Rock Mechanics and Rock Engineering ◽

10.1007/s00603-014-0609-6 ◽

2014 ◽

Vol 48 (3) ◽

pp. 1001-1016 ◽

Cited By ~ 62

Author(s):

M. H. Ghobadi ◽

R. Babazadeh

Keyword(s):

Thermal Shock ◽

Mechanical Characteristics ◽

Experimental Studies ◽

Salt Crystallization ◽

Physical And Mechanical Characteristics

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Fracture Toughness Investigation on Long Kenaf/Woven Glass Hybrid Composite Due To Water Absorption Effect

Procedia Engineering ◽

10.1016/j.proeng.2012.07.366 ◽

2012 ◽

Vol 41 ◽

pp. 1667-1673 ◽

Cited By ~ 47

Author(s):

Z. Salleh ◽

Y.M. Taib ◽

Koay Mei Hyie ◽

M. Mihat ◽

M.N. Berhan ◽

...

Keyword(s):

Fracture Toughness ◽

Water Absorption ◽

Hybrid Composite ◽

Absorption Effect ◽

Water Absorption Effect

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Pattern Dynamics of Vegetation Growth With Saturated Water Absorption

Frontiers in Physics ◽

10.3389/fphy.2021.721115 ◽

2021 ◽

Vol 9 ◽

Author(s):

Li Li ◽

Jia-Hui Cao ◽

Xin-Yue Bao

Keyword(s):

Water Absorption ◽

Vegetation Dynamics ◽

Vegetation Pattern ◽

Typical Feature ◽

Water Model ◽

Absorption Effect ◽

Vegetation Growth ◽

Pattern Dynamics ◽

Saturated Water ◽

Water Absorption Effect

Regular pattern is a typical feature of vegetation distribution and thus it is important to study the law of vegetation evolution in the fields of desertification and environment conservation. The saturated water absorption effect between the soil water and vegetation plays an crucial role in the vegetation patterns in semi-arid regions, yet its influence on vegetation dynamics is largely ignored. In this paper, we pose a vegetation-water model with saturated water absorption effect of vegetation. Our results show that the parameter 1/P, which is conversion coefficient of water absorption, has a great impact on pattern formation of vegetation: with the increase of P, the density of vegetation decrease, and meanwhile it can induce the transition of different patterns structures. In addition, we find that the increase of appropriate precipitation can postpone the time on the phase transition of the vegetation pattern. The obtained results systematically reveal the effect of saturated water absorption on vegetation systems which well enrich the findings in vegetation dynamics and thus may provide some new insights for vegetation protection.

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Investigation of the Various Binders’ Effect on the Lime Binder Carbonate Hardening Process for its Use in Additive Technologies

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1011.123 ◽

2020 ◽

Vol 1011 ◽

pp. 123-129

Author(s):

Alexander Bakhtin ◽

Nikolay Lyubomirskiy ◽

Tamara Bakhtina ◽

Vitaliy Nikolaenko

Keyword(s):

Inkjet Printing ◽

Mass Fraction ◽

Mechanical Characteristics ◽

Experimental Studies ◽

Hydrated Lime ◽

Additive Technologies ◽

High Concentration ◽

Hardening Process ◽

Materials Used ◽

Physical And Mechanical Characteristics

The obtaining carbonized material experimental studies’ results based on lime carbonate systems by 3D inkjet printing are presented. Some types of materials used as binders for inorganic binders have been studied. An effective method of hardening the model obtained in the 3D printing process is determined. The physical and mechanical characteristics of the prototypes hardened in the carbon dioxide medium or high concentration are determined. It was found that artificial carbonization of the samples obtained on various types of binders for 90 min contributes to the formation of a fairly strong structure of insoluble calcium carbonate, the hydrated lime carbonation product, and the carbonization degree depends on the type of binder and its mass fraction in the solution. The most effective types of binders were selected and the optimal content of the studied binders in the solution was determined.

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Composite Polymer Mesh For Masonry

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2019.11.15-19 ◽

2019 ◽

pp. 15-19

Keyword(s):

Strain State ◽

Mechanical Characteristics ◽

Experimental Studies ◽

Structural Elements ◽

Composite Polymer ◽

Performance Technology ◽

Different Types ◽

Composite Grids ◽

And Performance ◽

Physical And Mechanical Characteristics

With the development and introduction of technologies for the production of composite materials for construction purposes in Russia appeared composite flexible ties, anchors, fittings, etc. These materials and products are not fundamentally new and have previously been studied for use for reinforcing concrete or structural elements. However, for increasing the bearing capacity of stone structures as masonry meshes they were practically not used, while masonry mesh is one of the most demanded materials in construction. The article presents experimental studies of composite meshes of different types and performance technology used in masonry. Experimentally substantiated and normalized values of physical and mechanical characteristics of rods for composite polymer grids are obtained. The evaluation of efficiency of composite meshes in masonry is made, the values of crack forming and rupture loads are determined, the peculiarities of the stress-strain state of composite grids as flexible ties are revealed, the fields of application are formulated.

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The water absorption effect on the hardness of composites polyester

10.1063/1.4945971 ◽

2016 ◽

Author(s):

A. A. Mohammed ◽

T. T. Issa

Keyword(s):

Water Absorption ◽

Absorption Effect ◽

Water Absorption Effect

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Управление физико-механическими характеристиками бетона за счет варьирования высоты и шага технологических выступов хомутов виброцентрифугирующих устройств

ВЕСТНИК ИНЖЕНЕРНОЙ ШКОЛЫ ДВФУ ◽

10.24866/2227-6858/2021-1-12 ◽

2021 ◽

Vol 46 (1) ◽

Author(s):

Keyword(s):

Tensile Strength ◽

Compressive Strength ◽

Cross Section ◽

Mechanical Characteristics ◽

Experimental Studies ◽

Strength Analysis ◽

Technological Parameters ◽

Axial Tensile ◽

Concrete Mix ◽

Physical And Mechanical Characteristics

Для регулирования вариатропной структуры центрифугированных изделий авторы данной статьи совместили процесс центрифугирования с вибрированием. Во время эксперимента вибрации формы обеспечивались за счет надетых на валы установки хомутов. Представлена авторская экспериментальная установка для создания виброцентрифугированных образцов кольцевого сечения с вариатропной структурой, а также способ их изготовления. Выделены технологические параметры вибрирования, которые оказывали наиболее значимое влияние на характеристики виброцентрифугированного бетона, конструкций и изделий из него. В опытах варьировались высота технологических выступов хомутов и шаг между ними. Исследовалось влияние этих факторов на физико-механические характеристики бетона: плотность; кубиковая прочность на сжатие; призменная прочность на сжатие; прочность на растяжение при изгибе; прочность на осевое растяжение. Приведен анализ результатов экспериментальных исследований и получены следующие физико-механические характеристики виброцентрифугированных бетонов, изготовленных с использованием хомутов: лучшие – с высотой технологических выступов 5 мм и шагом между ними 30 мм, самый низкий показатель – соответственно 2,5 мм при любом шаге. Ключевые слова: виброцентрифугированный бетон, физико-механические характеристики, прочность при сжатии, плотность, бетонная смесь, центрифугирование, прочность при изгибе To regulate the variatropic structure of centrifuged products, the authors of this article combined the process of centrifugation with vibration. During the experiment, vibrations of the mold were provided with clamps set on the shafts of the installation. The author's experimental setup for creating vibrocentrifuged samples of annular cross-section with a variatropic structure, as well as a method for their manufacture is presented. The technological parameters of vibration, which had the most significant effect on the characteristics of vibrocentrifuged concrete, structures and products made of it, were identified. In the experiments, the height of the technological protrusions of the clamps and the pitch between them were varied. The influence of these factors on the physical and mechanical characteristics of concrete was investigated: density; cube compressive strength; prismatic compressive strength; bending tensile strength; axial tensile strength. Analysis of the results of experimental studies is given and the following physical and mechanical characteristics of vibrocentrifuged concretes made using clamps have been obtained: the best ones with a height of technological protrusions of 5 mm and a step between them of 30 mm, the lowest indicator is, respectively, 2.5 mm at any step. Keywords: vibrocentrifuged concrete, physical and mechanical characteristics, compressive strength, density, concrete mix, centrifugation, flexural strength

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Determining the mechanical characteristics of composite materials reinforced with woven preforms

Eastern-European Journal of Enterprise Technologies ◽

10.15587/1729-4061.2021.225112 ◽

2021 ◽

Vol 1 (7 (109)) ◽

pp. 41-50

Author(s):

Maryna Shevtsova ◽

Andrii Kondratiev ◽

Oleksii Andrieiev

Keyword(s):

Composite Materials ◽

Mechanical Characteristics ◽

Experimental Studies ◽

Compression Tests ◽

Study Program ◽

Good Convergence ◽

Variable Nature ◽

Rod System ◽

Rod Model ◽

Physical And Mechanical Characteristics

Reduction of the complexity of production of articles from composite materials is largely ensured by the use of reinforcing semi-finished products in which fibers pre-form a framework. Among all the variety of reinforcing systems, woven sleeves (preforms) occupy a special place. The high degree of deformability in a nonimpregnated condition makes it possible to lay this reinforcement on any surface without folds and cuts that provide preservation of strand continuity. This advantage of woven sleeves is accompanied by a change in local reinforcement angles and, consequently, the variable nature of physical and mechanical characteristics of the curved part surface. A method for calculating physical and mechanical characteristics of the composite based on preforms at any point of the part depending on the pattern of laying strands on a curved surface has been developed. The possibility of application of the rod model of the composite to describe physical and mechanical characteristics of the composite material with a woven reinforcement was analyzed. The model essence consists in that the composite is modeled by a diamond-shaped rod system. The rhombus sides serve as fibers and the diagonals as the binder. To verify the theoretical results and substantiate practical recommendations, a series of experimental studies were performed based on the formation of material specimens from two types of woven sleeves with different reinforcement angles. The experimental study program included tensile, bending, and compression tests. A fairly good convergence of theoretical and experimental data was obtained. For example, a square of the correlation coefficient was not less than 0.95 for the modulus of elasticity, not less than 0.8 for the Poisson's ratio, and not less than 0.9 for tensile and compressive strengths. This is the rationale for using the rod model to describe the considered class of composites. The use of the developed procedure will make it possible to increase the perfection of the considered class of designs and obtain rational parameters of the process of their manufacture.

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DURABILITY ASSESSMENT OF BENDING STRUCTURES MADE OF NONLINEAR ELASTIC MATERIAL

International Journal for Computational Civil and Structural Engineering ◽

10.22337/2587-9618-2020-16-4-80-85 ◽

2020 ◽

Vol 16 (4) ◽

pp. 80-85

Author(s):

Vladilen Petrov ◽

Roman Mishchenko ◽

Dmitry Pimenov

Keyword(s):

Mathematical Model ◽

Mechanical Characteristics ◽

Negative Impact ◽

Experimental Studies ◽

Field Tests ◽

Corrosive Media ◽

Nonlinear Elastic Material ◽

Durability Assessment ◽

Nonlinear Elastic ◽

Physical And Mechanical Characteristics

Experimental studies and field tests indicate that the effect of corrosive media leads to significant changes in the physical and mechanical characteristics of structural materials. The article proposes a mathematical model that allows predicting the negative impact of aggressive media and assessing the durability of bent structures.

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