scholarly journals Various ways to build effective characteristics for a pipe made of a layered composite material

2019 ◽  
Vol 97 ◽  
pp. 02027
Author(s):  
Tatiana Bobyleva ◽  
Alexey Shamaev
Keyword(s):  
Composite Materials ◽  
Computer Calculation ◽  
Analytical Form ◽  
Homogenization Method ◽  
Layered Composite ◽  
Effective Characteristics ◽  
Stiffness Characteristics ◽  
Analytical Result ◽  
Materials Used ◽  
The Individual

Composite materials consisting of several phases are widely used in modern construction. Numerous experiments have shown that the properties of structurally heterogeneous materials can differ significantly from those of the individual components making up the composition. Besides, rapidly changing coefficients of differential equations describing such composite materials greatly complicate the solution of boundary value problems even with the help of computer calculation methods. Therefore, the homogenization method is used. In this paper the two approaches propose to obtain in explicit analytical form the effective model of the problem of loading a heterogeneous pipe made of layered material, provided that the elastic properties of the material depend only on the distance from the center of the section of the pipe. We point to a method that obviously leads to an analytical result. It follows from the article that it is possible to choose the function that determines the structure of the “winding” in such a way as to obtain the stiffness characteristics of the pipe as close as possible to the desired with fixed mass fractions of the materials used. A similar approach can be applied to the study of creep properties of pipes made of composite materials.

scholarly journals Some methods for calculating and optimizing the characteristics of rods made of composite materials

2019 ◽  
Vol 138 ◽  
pp. 01035
Author(s):  
Tatiana Bobyleva ◽  
Alexey Shamaev
Keyword(s):  
Composite Materials ◽  
Computer Calculation ◽  
Analytical Form ◽  
Homogenization Method ◽  
Calculation Methods ◽  
Mass Fractions ◽  
Stiffness Characteristics ◽  
Analytical Result ◽  
Materials Used ◽  
The Individual

Composite materials consisting of several phases are widely used in modern construction. Numerous experiments have shown that the properties of structurally heterogeneous materials can differ significantly from those of the individual components making up the composition. Besides, rapidly changing coefficients of differential equations describing such composite materials greatly complicate the solution of boundary value problems even with the help of computer calculation methods. Therefore, the homogenization method is used. In this paper the approach propose to obtain in explicit analytical form the effective model of the problem of loading a heterogeneous pipe made of layered material, provided that the elastic properties of the material only depend on the distance from the center of pipe cross section. We point to a method that obviously leads to an analytical result. It follows from the article that it is possible to choose the function that determines the structure of the “winding” in such a way as to obtain the stiffness characteristics of the pipe as close as possible to the desired with fixed mass fractions of the materials used.

scholarly journals A Comparison of Experimental and Computation Results of Finding Effective Characteristics of Elastic Properties of Polymer Layered Composites from Carbon and Glass Fabrics

2021 ◽  
pp. 88-105
Author(s):  
A. Yu Muyzemnek ◽  
T. N Ivanova ◽  
E. D Kartashova
Keyword(s):  
Composite Materials ◽  
Elastic Properties ◽  
Computational Methods ◽  
Experimental Studies ◽  
Tensile Tests ◽  
Layered Composite ◽  
Experimental Results ◽  
Effective Characteristics ◽  
Shear Moduli ◽  
Bridge Model

Anisotropy of mechanical properties of the entire material and each of its layers is characteristic for polymer layered composite materials, as well as the fact that production processes of the composite material and parts from it are often combined in time. In this case, the elastic properties and strength of the material will be different not only in the thickness of the part, but also at each point. All this leads to a complication of the design process, which is due to the need to determine the elastic properties and strength of the polymer layered composite materials, taking into account the structure of the entire material and each of its layers. This work aims at evaluating the existing computational methods of finding effective characteristics of elastic properties by comparing computation results obtained by various methods with each other, as well as with the experimental results related to elastic properties of polymer layered composite materials from carbon and glass fabrics. We estimated the computational methods of finding effective characteristics of the elastic properties of composites based on the experimental results of finding the characteristics of the elastic properties of polymer layered composite materials made of carbon and glass fabrics, differing in density and type of weaving. The experimental values of the effective characteristics of elastic properties were determined as a result of standard tensile tests of laboratory specimens. As a result of the study, it was found that all the considered models and methods give consistent results when calculating the longitudinal modulus of elasticity E 11, the results of calculating shear modulus E 33 and shear moduli G 12 and G 23 are less consistent for all the considered materials. The comparison of the results of the experimental studies and computations showed that the Chamis model and the bridge model are better than other models to predict the values of the longitudinal elastic modulus.

scholarly journals Equations of dynamic and static problems of nonhomogeneous and anisotropic elastic layered-composite plates

1996 ◽  
Vol 18 (2) ◽  
pp. 35-42
Author(s):  
Pham Thi Toan
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Composite Plates ◽  
Homogenization Method ◽  
Layered Composite ◽  
Layered Plate ◽  
Governing Equations ◽  
Plate Method ◽  
Anisotropic Elastic ◽  
Anisotropic Elastic Material

The homogenization method for studying composite materials had been introduced in [1]. By this method the problem of nonhomogeneous and anisotropic elastic layered w composite material reduces to the set of problems of homogeneous, anisotropic elastic material. In this paper the governing equations of dynamic and static problems of layered - composite plates are formulated. An example is considered, obtained results can be compared with ones of multi-layered plate method.

scholarly journals Double-layered fiber for lightweight flexible clothing providing shielding from low-dose natural radiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seon-Chil Kim ◽  
Jun Sik Son
Keyword(s):  
Low Dose ◽  
Layered Composite ◽  
Radiation Shielding ◽  
Flight Attendants ◽  
Low Dose Radiation ◽  
Natural Radiation ◽  
Composite Yarn ◽  
Materials Used ◽  
Fiber Fabric ◽  
Dose Radiation

AbstractNatural and medical radiation are the most frequent sources of daily low-dose radiation exposure for the general public, but these radiation levels are generally acceptable. Among various occupations, aviation crew members and medical workers are exposed to high levels of radiation from scattered rays. This study focused on developing clothing for shielding aviation crew members from natural radiation during air travel. Materials were selected considering their radiation-shielding properties. A tungsten double-layered composite yarn and a polyethylene terephthalate (PET) fiber fabric containing BaSO4 were manufactured. The characteristics and shielding performances of the products were analyzed. Prototypes of a protective scarf (for shielding the thyroid gland) and apron (for shielding the torso) for flight attendants were produced. A lightweight fabric was produced that neither restricts the movement of the wearer nor causes them skin discomfort. The shielding performances of the tungsten composite and PET fiber fabrics containing BaSO4 were 0.018 mmPb and 0.03 mmPb, respectively, demonstrating low-dose shielding that may be useful for protecting aviation crew members from scattered rays. The characteristics of the developed fibers are comparable to those of materials used in clothing production; therefore, low-dose radiation-shielding clothing could be manufactured for use in aviation, medical, and other industries.

scholarly journals Preparation and Properties of Layered SiC-Graphene Composites for EDM

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2916
Author(s):  
Ondrej Hanzel ◽  
Zoltán Lenčéš ◽  
Peter Tatarko ◽  
Richard Sedlák ◽  
Ivo Dlouhý ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Surface Layer ◽  
Positive Influence ◽  
Layered Composite ◽  
Layered Composites ◽  
Good Adhesion ◽  
Electric Discharge Machining ◽  
Layer Sequence ◽  
The Individual ◽  
Scratch Tests

Three and five-layered silicon carbide-based composites containing 0, 5, and 15 wt.% of graphene nanoplatelets (GNPs) were prepared with the aim to obtain a sufficiently high electrical conductivity in the surface layer suitable for electric discharge machining (EDM). The layer sequence in the asymmetric three-layered composites was SiC/SiC-5GNPs/SiC-15GNPs, while in the symmetric five-layered composite, the order of layers was SiC-15GNPs/SiC-5GNPs/SiC/SiC-5GNPs/SiC-15GNPs. The layered samples were prepared by rapid hot-pressing (RHP) applying various pressures, and it was shown that for the preparation of dense 3- or 5-layered SiC/GNPs composites, at least 30 MPa of the applied load was required during sintering. The electrical conductivity of 3-layered and 5-layered composites increased significantly with increasing sintering pressure when measured on the SiC surface layer containing 15 wt.% of GNPs. The increasing GNPs content had a positive influence on the electrical conductivity of individual layers, while their instrumented hardness and elastic modulus decreased. The scratch tests confirmed that the materials consisted of well-defined layers with straight interfaces without any delamination, which suggests good adhesion between the individual layers.

scholarly journals Extracting interface correlations from the pair distribution function of composite materials

Nanoscale ◽  
2021 ◽  
Author(s):  
Harry Geddes ◽  
Henry Hutchinson ◽  
Alex R Ha ◽  
Nicholas P Funnell ◽  
Andrew Goodwin
Keyword(s):  
Distribution Function ◽  
Composite Materials ◽  
Pair Distribution Function ◽  
Complex Mixtures ◽  
Individual Phase ◽  
The Individual ◽  
Matrix Factorisation

Using a non-negative matrix factorisation (NMF) approach, we show how the pair distribution function (PDF) of complex mixtures can be deconvolved into the contributions from the individual phase components and...

Mechanical characterization of a woven multi-layered hyperelastic composite laminate under uniaxial loading

2021 ◽  
pp. 002199832110115
Author(s):  
Shaikbepari Mohmmed Khajamoinuddin ◽  
Aritra Chatterjee ◽  
MR Bhat ◽  
Dineshkumar Harursampath ◽  
Namrata Gundiah
Keyword(s):  
Composite Materials ◽  
Energy Function ◽  
Strain Energy ◽  
Strain Energy Function ◽  
Mechanical Tests ◽  
Stress Strain ◽  
Aerospace Applications ◽  
Envelope Material ◽  
The Individual ◽  
High Dielectric

We characterize the material properties of a woven, multi-layered, hyperelastic composite that is useful as an envelope material for high-altitude stratospheric airships and in the design of other large structures. The composite was fabricated by sandwiching a polyaramid Nomex® core, with good tensile strength, between polyimide Kapton® films with high dielectric constant, and cured with epoxy using a vacuum bagging technique. Uniaxial mechanical tests were used to stretch the individual materials and the composite to failure in the longitudinal and transverse directions respectively. The experimental data for Kapton® were fit to a five-parameter Yeoh form of nonlinear, hyperelastic and isotropic constitutive model. Image analysis of the Nomex® sheets, obtained using scanning electron microscopy, demonstrate two families of symmetrically oriented fibers at 69.3°± 7.4° and 129°± 5.3°. Stress-strain results for Nomex® were fit to a nonlinear and orthotropic Holzapfel-Gasser-Ogden (HGO) hyperelastic model with two fiber families. We used a linear decomposition of the strain energy function for the composite, based on the individual strain energy functions for Kapton® and Nomex®, obtained using experimental results. A rule of mixtures approach, using volume fractions of individual constituents present in the composite during specimen fabrication, was used to formulate the strain energy function for the composite. Model results for the composite were in good agreement with experimental stress-strain data. Constitutive properties for woven composite materials, combining nonlinear elastic properties within a composite materials framework, are required in the design of laminated pretensioned structures for civil engineering and in aerospace applications.

Surface Charging Considerations for Composite Materials Used in Spacecraft Applications

2015 ◽  
Vol 43 (9) ◽  
pp. 2901-2906
Author(s):  
Justin J. Likar ◽  
Robert E. Lombardi ◽  
Alexander L. Bogorad ◽  
Roman Herschitz
Keyword(s):  
Composite Materials ◽  
Surface Charging ◽  
Materials Used
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