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1.
A variant of determining the elastic characteristics of composites containing irregularly oriented shape-anisotropic filler
particles of two types (short fibers and thin platelets) is considered. The effective elastic constants of the composites
are calculated by using the method of orientational averaging of elastic characteristics of isolated transversely isotropic
structural elements reinforced with unidirectionally oriented short fibers or coplanarly arranged thin platelets. The superposition
of elastic properties of the irregularly oriented structural elements, with account of their orientational distribution in
the composite material, is accepted. The calculation results are compared with experimental data for the effective elastic
moduli of polymeric composites reinforced with short glass fibers and of polymeric nanocomposites containing the platelet-type
particles of organically modified montmorillonite.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 3, pp. 285–300, May–June, 2006. 相似文献
2.
R. D. Maksimov S. Gaidukovs J. Zicans M. Kalnins E. Plume V. Spacek P. Sviglerova 《Mechanics of Composite Materials》2006,42(3):263-272
The preparation of polymer nanocomposites by mixing a solution of a styrene-acrylate copolymer with a suspension of organically
modified montmorillonite in dimethyl formamide is described. Seven different compositions with organomontmorillonite content
from 0 to 7 wt.% were prepared and tested. Results of their X-ray diffraction analysis are presented. Data on the influence
of organomontmorillonite content on the tensile stress-strain curves, elastic modulus, strength, and ultimate elongation of
the nanocomposites are obtained. The concentration dependences of elastic properties of materials with differently oriented
platelike nanoparticles is analyzed by using an algorithm elaborated for stepwise calculations of elastic constants with account
of the features of structural hierarchy of intercalated and exfoliated nanocomposites.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 3, pp. 375–388, May–June, 2006. 相似文献
3.
Analysis results for the elastic properties of a composite with a small amount of coplanarly arranged platelike filler particles
are presented. The geometrical form of the particles is described by an oblate ellipsoid of revolution. The calculations are
performed by formulas obtained by using the Eshelby approach for media with a low concentration of inclusions. The effect
of anisometry of the ellipsoidal particles and of the ratio between the elastic moduli of the filler and matrix on the effective
elastic constants of the composite is discussed. Calculation results are compared with experimental data for the elastic moduli
of a nanocomposite containing completely exfoliated particles of an unmodified montmorillonite.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 4, pp. 493–504, July–August, 2008. 相似文献
4.
N. Lilichenko R. D. Maksimov J. Zicans R. Merijs Meri E. Plume 《Mechanics of Composite Materials》2008,44(1):45-56
The preparation of an environmentally friendly nanocomposite based on plasticized potato starch and unmodified montmorillonite
clay is described. Data on the influence of montmorillonite concentration on the mechanical properties of the materials obtained
are reported. The effective elastic constants of the nanocomposites are calculated. The calculation results are compared with
experimental data. The influence of montmorillonite content on the moisture permeability is also investigated.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 1, pp. 61–76, January–February, 2008. 相似文献
5.
Within the framework of fractal analysis and percolation theory, an alternative model of reinforcement of filled polymers
is offered. Practically, this model can be used only to describe the reinforcement of nanocomposites, because, according to
the treatment considered, a pronounced reinforcement can be reached only at ratios of filler particle diameter to the statistical
segment length of about 10 and less. A theoretical calculation showed a good qualitative and quantitative agreement with experiments.
The type of reinforcement mechanism of composites is determined by the type of the space (fractal or Euclidean) in which the
structure of the polymeric matrix is formed.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 6, pp. 797–802, November–Decem ber, 2006. 相似文献
6.
R. D. Maksimov S. Gaidukov J. Zicans J. Jansons 《Mechanics of Composite Materials》2008,44(5):505-514
Results of an investigation into the kinetics of moisture sorption by an unfilled styrene-acrylate copolymer and a nanocomposite
containing unmodified montmorillonite clay are reported. The sorption tests were performed at 25°C and different levels of
the relative humidity of air up to 80%. The moisture diffusivity was calculated using Fick's equation for one-dimensional
diffusion. Data on the influence of montmorillonite concentration on the coefficients of diffusion, solubility, and permeability
are obtained. The experimental values of the permeability coefficient are compared with those calculated by using a model
taking into account the increased path of a diffusing water molecule caused by the shielding effect of plate like filler particles.
Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 5, pp. 723–736, September–October, 2008. 相似文献
7.
S. B. Sapozhnikov A. N. Aniskevich V. A. Tsarevskii 《Mechanics of Composite Materials》2006,42(6):571-576
A numerical method for predicting the deformational and strength characteristics of a calcite-quartzitic polymer concrete
from the known properties of its components is developed based on the finite-element method. Components of the material are
assumed elastic and isotropic, and the filler particles are modeled by round inclusions perfectly bonded to the polymer matrix.
The size distribution of the inclusions correspond to that of actual fillers. The destruction process of the components is
simulated by sequentially excluding the particles in which the maximum principal stress has achieved the ultimate value for
this component. A comparison of calculated and experimental characteristics of the polymer concrete showed errors of 2–4%
for the elastic modulus and about 10% for the ultimate strength if the finite-element cell included not less than 20–30 average-size
particles and 2–5 large ones.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 6, pp. 817–824, November–December, 2006 相似文献
8.
The effects of orientation and shape of filler particles on the elastic properties of composites have been analyzed. The elastic
constants of a composite with irregularly oriented filler particles were calculated by using the method of orientational averaging
of the properties of a representative structural element. The elastic constants of the structural element were found according
to a known generalized Eshelby solution for a finite concentration of ellipsoidal inclusions. The diagrams of elasticity anisotropy
for a transversely isotropic structural element and an orthotropic composite with irregularly oriented inclusions are presented.
A quantitative estimate for the degree of anisotropy of elastic properties of composites is suggested. Data on the influence
of shape anisometry of inclusions on the anisotropy coefficient of filled composites are also reported. 相似文献
9.
Bending of an elastic annular composite plate with a light filler lying on an elastic foundation is considered. The plate
is subjected to local loads. To describe the kinematics of the package, asymmetric across its thickness, the hypotheses of
broken normal is accepted. The reaction of foundation is described based on the Winkler model. A system of equilibrium equations
is constructed, and its exact solution in displacements is found. Numerical solutions for a metal-polymer sandwich plate are
presented.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 43, No. 1, pp. 109–120, January–February, 2007. 相似文献
10.
E. A. Aliyev 《Mechanics of Composite Materials》2007,43(6):521-534
Within the framework of a piecewise homogenous body model and with the use of a three-dimensional linearized theory of stability
(TLTS), the local near-surface buckling of a material system consisting of a viscoelastic (elastic) half-plane, an elastic
(viscoelastic) bond layer, and a viscoelastic (elastic) covering layer is investigated. A plane-strain state is considered,
and it is assumed that the near-surface buckling instability is caused by the evolution of a local initial curving (imperfection)
of the elastic layer with time or with an external compressive force at fixed instants of time. The equations of TLTS are
obtained from the three-dimensional geometrically nonlinear equations of the theory of viscoelasticity by using the boundary-form
perturbation technique. A method for solving the problems considered by employing the Laplace and Fourier transformations
is developed. It is supposed that the aforementioned elastic layer has an insignificant initial local imperfection, and the
stability is lost if this imperfection starts to grow infinitely. Numerical results on the critical compressive force and
the critical time are presented. The influence of rheological parameters of the viscoelastic materials on the critical time
is investigated. The viscoelasticity of the materials is described by the Rabotnov fractional-exponential operator.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 43, No. 6, pp. 771–788, November–December, 2007. 相似文献
11.
R. D. Maksimov S. Gaidukovs J. Zicans M. Kalnins E. Plume V. Spacek P. Sviglerova 《Mechanics of Composite Materials》2006,42(4):353-362
The results of an investigation into the barrier and thermal properties of polymer nanocomposites prepared by blending a styrene-acrylate
copolymer solution with a suspension of organically modified montmorillonite are presented. The influence of organomontmorillonite
content on the barrier properties of the nanocomposite is investigated with the example of water vapor permeability. The experimental
values of the permeability coefficient are compared with those calculated by using a model taking into account the increased
path of diffusing water molecules caused by the shielding effect of plate like particles. The thermograms of differential
scanning calorimetry in the temperature range from −40 to 130°C are presented. The results of a thermogravimetric analysis
for specimens heated in air to 800°C are also reported.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 4, pp. 503–516, July–August, 2006. 相似文献
12.
Based on a plane model of composites, the effect of a transition layer on the elastic modulus Ec of the composites is analyzed in the case where, under the action of a load, the transition layer is formed both on the side
of matrix and filler. In evaluating Ec, it is assumed that the elastic modulus in the layer grows linearly from the elastic modulus of matrix to that of filler,
but pores in the filler are impermeable to matrix macromolecules. Analytic relation ships are found which allow one to determine
the volume fractions of the transition layer on the side of matrix and filler if the experimental elastic modulus of the composite
is known. These relationships are used to find the magnitude of the layer in epoxy composites with various fillers and to
evaluate its effect on the compressive elastic modulus of the composites.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 5, pp. 693–700, September–October, 2006. 相似文献
13.
A variant of a stepwise analysis of the elastic properties of a carbon-nanotube-reinforced composite with account of the effect
of interphase layers between the nanotubes and the polymer matrix is reported. The preliminary calculation of the elastic
constants of a structural element incorporating a nanotube and an interphase layer and the subsequent calculation of independent
elastic constants of a composite with such transversely isotropic structural elements oriented in one direction are both performed
by using the Mori–Tanaka theory of an equivalent medium. The calculations are carried out for a wide range of ratios between
the elastic moduli of the interphase layer and matrix. The elastic constants of a composite with randomly oriented nanotubes
are obtained by using the method of orientational averaging. 相似文献
14.
Sodium fluorohectorite (FH) was incorporated into polystyrene (PS) in amounts of 4.5 and 7 wt.% by melt mixing, with and without
latex precompounding. The latex precompounding was used for the latex-mediated predispersion of FH particles. The related
masterbatch was produced by mixing PS latex with the water-swellable FH, followed by drying. The dispersion of FH in PS was
studied by transmission-, scanning electron-, and atomic force microscopy techniques (TEM, SEM, and AFM, respectively). The
stress relaxation in the PS composites was determined in short-term isothermal tests. The latter were performed at various
temperatures between 25 and 75°C. The direct melt mixing of FH with PS resulted in microcomposites, whereas the masterbatch
technique gave rise to nanocomposites. The master curves (relaxation modulus vs. time), constructed by applying the time-temperature
superposition principle (TTSP), showed that the Williams-Landel-Ferry (WLF) equation, the Maxwell model, and the Findley power
law were fairly applicable to the experimental results obtained.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 44, No. 5, pp. 709–722, September–October, 2008. 相似文献
15.
The plane problem of three-dimensional stability is solved for a transversely compressed composite material reinforced with
ribbons taking into account the inhomogeneous initial state. An approximate solution of the problems is based on the net method.
The effect of the ribbon form factor, the ratio between the elastic moduli of the matrix and filler, and Poisson ratio of
the filler on the critical deformation of the material is investigated.
Translated from Mekhanika Kompozitnykh Materialov, Vol. 36, No. 1, pp. 77–86, January–February, 2000. 相似文献
16.
An attempt is made to find a solution by which the effect of neighboring filler particles on the strength of composites could
be indirectly estimated. The stresses in composites with a great amount of filler are calculated. Composites based on epoxy-resin
binder are tested. A comparison of different models shows that the modified Kerner model reflects only the tendency for the
compression strength to change with the degree of filling. The relations between the compression strength and the degree of
filling are better described by models allowing for constraint of the plastic deformations of the matrix. However, in this
case, the effect of the neighboring particles is not properly taken into account.
Translated from Mekhanika Kompozitnykh Materialov, Vol. 35, No. 5, pp. 575–584, September–October, 1999. 相似文献
17.
The first part of the paper deals with homogenization models of unidirectional composites, in which each phase of the material
is bounded by parallel cylindrical surfaces. For a GFRP with epoxy resin and glass fibres, five elastic constants for six
models of the composite are calculated. In the second part, the results of strain gauge tests, photoelasticity investigations,
and scanning electron inspection are discussed. With these data, some elastic constants of the composite in tension and compression
are found. A comparison of experimental and analytical results is presented.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 44, No. 2, pp. 195–206, March–April, 2008. 相似文献
18.
The study aims to predict the elastic and damping properties of composite laminated plates from measured dynamical characteristics.
The elastic constants and damping properties of a laminated element are determined by using experimental data and the results
of a multilevel theoretical approach. Solution examples for particular problems are given.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 1, pp. 35–50, January–February, 2008. 相似文献
19.
The operational properties (strength, heat conductivity, hygroscopic sorption, vapor permeability, and frost resistance) of
a heat-insulation composite of density 150–350 kg/m3 are investigated. The matrix consists of an aerated concrete substance and a disperse filler of expanded polystyrene crumbs
obtained by crushing the household polystyrene package waste. The macro-and microstructure of the composite are considered.
It is found that the operational properties of the material directly depend on its density, determined by the amount of the
cementing substance in the matrix.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 4, pp. 591–604, July–August, 2008. 相似文献
20.
L. A. Golotina L. L. Kozhevnikova T. B. Koshkina 《Mechanics of Composite Materials》2008,44(6):633-640
Composites with an elastomeric matrix containing rigid particles of diameter 10–1000 μm are studied. One of possible mechanisms
of the rheological behavior of such filled systems, related to the origination and growth of vacuoles near the rigid inclusions
in a viscous matrix, is considered. For simulating the mechanism of formation of rheological properties of the filled elastomers,
we use a structural cell in the form of an elastomeric cylinder, whose height and diameter are equal in magnitude, with a
rigid spherical inclusion at its center. Deformation of the cells is examined with the observance of boundary conditions providing
the preservation of their close packing. The inclusion is assumed to be rigid, and the matrix properties are described by
equations of the linear hereditary viscoelasticity theory. The formation of vacuoles is described by using the approach suggesting
that an initial debonding begins to propagate when the energy accumulated in the extended matrix reaches a value sufficient
to create a new interface. The heterogeneity of the composite is simulated by taking into account the variability of the local
filler concentration. Creep curves obtained for composite cells with different content of the solid phase are presented. Comparisons
between the numerical and experimental results show a satisfactory agreement.
Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 6, pp. 895–906, November–December, 2008. 相似文献