scholarly journals Determining the mechanical characteristics of composite materials reinforced with woven preforms

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.

Refractory Core-Shell Powders for Additive Industries

2017 ◽  
Vol 265 ◽  
pp. 529-534 ◽  
Author(s):  
Sergey P. Bogdanov ◽  
A.P. Garshin
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Composite Materials ◽  
Boron Nitride ◽  
Tungsten Carbide ◽  
Mechanical Characteristics ◽  
Core Shell ◽  
Refractory Materials ◽  
Iodide Transport ◽  
Physical And Mechanical Characteristics

The finished products obtained when the surfaces of powders of refractory materials (diamond, boron nitride, silicon carbide, tungsten carbide, tungsten) were coated with thin films by the method of iodide transport are presented. The developed method enables to obtain powder composite materials of core-shell type that have surface thickness varying in the range from 1 nm to several micrometers. From the powders modified by the films of metals and thier compounds composite materials were developed, their physical and mechanical characteristics were studied. The characteristics turned out to be substantially higher in comparison to materials sintered from the same powders but without coating. The probable fields of use of the composites in question were determined.

scholarly journals Study Smart-layer effect on the physical and mechanical characteristics of the samples from polymer composite materials under quasi-static loading

2020 ◽  
pp. 188-200
Author(s):  
G. S Shipunov ◽  
M. A Baranov ◽  
A. S Nikiforov ◽  
D. V Golovin ◽  
A. A Tihonova
Keyword(s):  
Composite Materials ◽  
Optical Fiber ◽  
Polymer Composite ◽  
Static Loading ◽  
Mechanical Characteristics ◽  
Fiber Optic ◽  
Fiber Optic Sensors ◽  
Polymer Composite Materials ◽  
Physicomechanical Characteristics ◽  
Physical And Mechanical Characteristics

Currently, developments of the so-called Smart-constructions are relevant as they enable a real-time monitoring of changes in required values. Smart designs are widely used in the construction, automotive and aerospace industries. Technologies of creating products from polymer composite materials make it possible to introduce various sensors directly into the structure of a material, thereby create systems monitoring the state of structures. The most recommended for such implementation are fiber-optic sensors, which have a number of advantages over other sensors (luminescent, strain gauge, piezoelectric ones). However, when introducing the fiber-optic sensors, there is a number of difficulties, which are primarily associated with fragility of the optical fiber and lead to the breakdown of fiber-optic lines. As a result, it is necessary to develop a Smart-layer that will protect the optical fiber leads and will not significantly change the physical and mechanical characteristics. This paper aims to determine the stiffness and strength characteristics of samples made of polymer composite materials: reference samples, samples with embedded fiber-optic sensors, samples with embedded Smart-layers. In this work, a Smart-layer is understood as a coating that protects the fiber-optic sensors at the stage of implementation into a structure. The paper considers the following configurations of the Smart-layer: polymer reinforced mesh, polyamide and polyurethane layer. We analyzed and compared the influence of the embedded optical fiber and various configurations of the Smart-layer in the composite structure on the physicomechanical characteristics of the samples obtained under quasi-static loading (tension, compression, and interlayer shear). For a more detailed analysis of using the fiber-optic sensors and various configurations of the Smart-layer, the corresponding loads were simulated to assess their mechanical behavior. Based on the obtained physical and mechanical characteristics, a specific configuration of the Smart-layer was selected and justified for further researches.

scholarly journals PHYSICO-MECHANICAL, THERMAL AND ELECTRICAL CHARACTERISTICS COMPOSITE MATERIALS BASED ON POLYURETHANE BINDER AND MINERAL FILLERS

2020 ◽  
pp. 14-21
Author(s):  
V. Sh. Sulaberidze ◽  
E. A. Skorniakova
Keyword(s):  
Composite Materials ◽  
Flame Retardants ◽  
Mechanical Characteristics ◽  
Elasticity Modulus ◽  
Electrical Characteristics ◽  
Dielectric Coatings ◽  
Fine Powders ◽  
Coefficient Of Elasticity ◽  
Mineral Fillers ◽  
Physical And Mechanical Characteristics

The article presents the results of studies of the physical, mechanical, thermal and electrical characteristics of composite materials based on polyurethane as a binder and mineral fillers from fine powders AlN, Al(OH)3, SiO2, CaSiO3 with a content of up to 70 wt.%. These composite materials are used to create modern sealants and dielectric coatings that meet special requirements for strength, elasticity, heat resistance, including those that do not support combustion (by using flame retardants). Dependences of tensile strength, coefficient of elasticity, modulus of elasticity under compression and hardness of samples, electrical resistivity and thermal conductivity on the mass content of the filler were determined. It was found that in terms of the combination of physical and mechanical characteristics, the compositions based on the applied polyurethane are more durable, elastic and resilient than compositions based on a silicone binder with the same fillers previously studied by the authors.

scholarly journals Mathematical Apparatus for the Synthesis of Composite Materials with Specified Properties

2021 ◽  
Vol 1203 (2) ◽  
pp. 022011
Author(s):  
Eugenia Budylina ◽  
Irina Garkina ◽  
Alexander Danilov
Keyword(s):  
Composite Materials ◽  
Technological Process ◽  
Cognitive Modeling ◽  
System Analysis ◽  
Mechanical Characteristics ◽  
Extreme Values ◽  
Optimization Problems ◽  
Quality Criteria ◽  
Kinetic Processes ◽  
Physical And Mechanical Characteristics

Abstract The meaning of the creation and functioning of the system is defined as the achievement of extreme values of goals that unite the individual elements of the system into a single whole. Based on this, the main system attributes of composite materials are indicated. It is assumed that the systemic effect is generated by the systemic properties of quality criteria. The implementation of the technical task is initially determined at the stage of cognitive modeling with the establishment of intensive and extensive properties with the allocation of control parameters. Based on the cognitive map, hierarchical structures of quality criteria are determined, and in accordance with the selected quality criteria, the corresponding structural schemes of the system (for each selected scale level). Further, the system's quality criteria are formalized, and mathematical models are developed in accordance with each of the criteria. The main purpose of using system analysis is to apply the general principles of decomposition of the system into individual elements and establish connections between them, in determining the research goal and stages to achieve this goal (based on solving single-criterion optimization problems using the found optimal values). The formalization of the multicriteria problem and its solution are made based on the required operational values, the type of kinetic processes of the formation of the physical and mechanical characteristics of the material (determine its structure and properties). The problem of materials synthesis is reduced to the choice of the order and type of the differential equation; parametric identification within the chosen model; comparison of experimental and model kinetic processes at a given accuracy; adjusting the model (if necessary). Therefore, it is important to interpolate the kinetic processes of the formation of the main physical and mechanical characteristics of composite materials. The technological process is considered as a complex system consisting of elements of various levels of detail: from atomic to a separate process. Decomposition of the technological process consists in dividing it into basic operations (elements): preparation of materials, mixing of components, molding of a semi-finished product, heat treatment and additional operations. The effectiveness of this approach was confirmed in the development of chemically resistant sulfur composites, epoxy composites for radiation protection, etc. The initial prerequisite was the required operational values of the material and the type of kinetic processes. The results of effective use of interpolation models (including splines) of compressive strength, heat release, and shrinkage of composite epoxy materials are presented.

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

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.

Composite Polymer Mesh For Masonry

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.

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

2019 ◽  
Vol 970 ◽  
pp. 202-209
Author(s):  
Olga V. Muravieva ◽  
Robert R. Khasanov ◽  
Viktor A. Strizhak ◽  
Sergey S. Mkrtchyan
Keyword(s):  
Water Absorption ◽  
Propagation Velocity ◽  
Mechanical Characteristics ◽  
Experimental Studies ◽  
Absorption Effect ◽  
Acoustic Waveguide ◽  
Torsional Waves ◽  
Water Absorption Effect ◽  
Waveguide Method ◽  
Physical And Mechanical Characteristics

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.

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

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

scholarly journals DURABILITY ASSESSMENT OF BENDING STRUCTURES MADE OF NONLINEAR ELASTIC MATERIAL

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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