scholarly journals Creep of a heterogeneous polymer cylindrical shell

2021 ◽  
Vol 1030 (1) ◽  
pp. 012091
Author(s):  
Vladimir Andreev ◽  
Batyr Yazyev
Keyword(s):  
Cylindrical Shell ◽  
Composite Materials ◽  
Internal Pressure ◽  
Mechanical Characteristics ◽  
Structural Elements ◽  
Filled Polymer ◽  
Heterogeneous Polymer ◽  
Physical And Mechanical Characteristics

Abstract The article deals with the problem of calculating an heterogeneous cylindrical shell made of a filled polymer, which is in the process of creep under the action of constant internal pressure and temperature. The calculation is based on the Maxwell -Gurevich equation, which has been repeatedly tested in the calculations of structural elements made of polymer and composite materials. The dependence of the physical and mechanical characteristics of the material on temperature is taken into account.

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.

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.

scholarly journals Optimization of Thick-Walled Viscoelastic Hollow Polymer Cylinders by Artificial Heterogeneity Creation: Theoretical Aspects

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2408
Author(s):  
Anton Chepurnenko ◽  
Stepan Litvinov ◽  
Besarion Meskhi ◽  
Alexey Beskopylny
Keyword(s):  
Cylindrical Shell ◽  
Internal Pressure ◽  
High Density Polyethylene ◽  
Mechanical Characteristics ◽  
Optimization Technique ◽  
Creep Process ◽  
Mass Content ◽  
Shell Optimization ◽  
Relationship Of ◽  
The Relationship

A theoretical solution of the problem of thick-walled shell optimization by varying the mechanical characteristics of the material over the thickness of the structure is proposed, taking into account its rheological properties. The optimization technique is considered by the example of a cylindrical shell made of high-density polyethylene with hydroxyapatite subjected to internal pressure. Radial heterogeneity can be created by centrifugation during the curing of the polymer mixed with the additive. The nonlinear Maxwell–Gurevich equation is used as the law describing polymer creep. The relationship of the change in the additive content along with the radius r, at which the structure is equally stressed following the four classical criteria of fracture, is determined in an elastic formulation. Moreover, it is shown that a cylinder with equal stress at the beginning of the creep process ceases to be equally stressed during creep. Finally, an algorithm for defining the relationship of the additive mass content on coordinate r, at which the structure is equally stressed at the end of the creep process, is proposed. The developed algorithm, implemented in the MATLAB software, allows modeling both equally stressed and equally strength structures.

scholarly journals Dynamic model of closure the liner

2020 ◽  
pp. 114-122
Author(s):  
I. V. Dmytriv I. V.
Keyword(s):  
Cylindrical Shell ◽  
Modulus Of Elasticity ◽  
Mechanical Characteristics ◽  
Vacuum Pressure ◽  
Design Parameters ◽  
Radial Deformation ◽  
Central Angle ◽  
Radial Plane ◽  
Working Length ◽  
Physical And Mechanical Characteristics

Annotation Purpose. Develop analytical dependences for modeling the speed and dynamics of deformation of liner depending on its design parameters and physical and mechanical characteristics, taking into account the technological parameters of the process. Methods. Based on the system of geometric equilibrium equations for a cylindrical shell, taking into account the isotropy of the medium and the momentless stress state, the spatial action of forces and pre-tension of the liner, developed analytical equations that allow modeling the dynamics of deformation of liner in time, which allows to determine the time constant of the system “liner – milking cup”. Results. Analytical dependences of the dynamics of deformation of liner in time in the radial plane and the rate of deformation depending on its design parameters and physical and mechanical characteristics of the material are developed. Parameters for deformation simulation are: R – radius of liner, Е – modulus of elasticity, ρ – the density of the rubber material, h – thickness of liner, рн – vacuum pressure, l – the length of the active part of liner, ν – Poisson's coefficient for rubber, Fн – force of tension of liner. Depending on the central angle in the radial plane of the section, the shape of the deformation of the liner is modeled along its entire working length during the closing and opening stroke. Conclusions. The obtained dependences allow to model the dynamics of deformation of liner in the radial plane depending on its design parameters and physical and mechanical characteristics of the material. The developed analytical dependences take into account the pre-tension of the liner, vacuum pressure and allows modeling depending on the central angle in the radial plane of the rubber section. The use of the developed analytical dependences makes it possible to substantiate the main parameters that affect the process of closing and opening of the liner. The characteristic of the deformation in the cross section of the largest deformation is that the tension of the liner does not affect the deformation characteristic. This is due to the isotropy property of the cylindrical shell and the elastic isotropic properties. Keywords: liner, vacuum pressure, modulus of elasticity, radial deformation, coordinate system, tension of rubber, the cylindrical shell, the isotropic medium.

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.

Determination of the Optimal Structure of a Layered Composite Material for Maximum Strength Characteristics

2021 ◽  
Vol 1040 ◽  
pp. 124-131
Author(s):  
Ljubov Aleksandrovna Bokhoeva ◽  
I.O. Bobarika ◽  
A.B. Baldanov ◽  
Vitaly Evdokimovich Rogov ◽  
Anna S. Chermoshentseva
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Mechanical Characteristics ◽  
Minimum Weight ◽  
Layered Composite ◽  
Number Of Layers ◽  
Reinforcing Material ◽  
Intensive Development ◽  
Physical And Mechanical Characteristics

Due to the intensive development of composite materials and technologies for producing parts from them, they are increasingly used in various industries, including the manufacture of products with increased requirements for the characteristics of final products (strength, stiffness, minimum weight, etc.). In this regard, the authors analyzed the possibility to optimize the layered structure of a composite material in order to give it a pronounced predictable anisotropy of properties required for the final product. Thus, the influence of the orientation of the fibers of the reinforcing material in different layers of the package and the number of layers of the package on the physical and mechanical characteristics of the hypothetical product were analyzed. The problem was solved through the example of the development of a wing for a hypothetical UAV.

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