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1.
The influence of a preliminary bending induced by misalignment of the grips of a testing machine on the stress-strain state
of a flat specimen made of a high-strength unidirectional carbon fiber composite under uniaxial tension is estimated. An analysis
of the analytical solution obtained is carried out, and the results of finite-element calculations and modeling experiments
are presented.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 43, No. 6, pp. 745–760, November–December, 2007. 相似文献
2.
The mixed-mode I + II interlaminar fracture of multidirectional glass/epoxy laminates is investigated. Mixed-mode bending
(MMB) tests were performed on specimens with delaminations in 0/θ-type interfaces, with θ varying from 0 to 90°. Preliminary
three-dimensional finite-element analyses validated the beam theory model (BTM) used for analysing experimental data. The
compliances measured are in a good agreement with BTM predictions. The total critical energy release rate Gc varies linearly with the mode II ratio GII/G, although some discrepancies are observed in the high-mode II results for the 0/45 and 0/90 specimens.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 43, No. 3, pp. 349–366, May–June, 2007. 相似文献
3.
S. V. Shlychkov 《Mechanics of Composite Materials》2007,43(3):269-276
The paper presents results of numerical and experimental investigations into the vibrations of thin-walled structures, considering
such their features as the complexity of geometry, the laminated structure of walls, the anisotropy of materials, the presence
of stiffeners, and the initial stresses. The object of the study is the sounding board of an acoustic guitar, the main structural
material of which is a three-layer birch veneer. Based on the finite-element method, a corresponding calculation model is
created, and the steady-state regimes of forced vibrations of the sounding board are investigated. A good correspondence between
calculation results and experimental data is found to exist.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 43, No. 3, pp. 399–410, May–June, 2007. 相似文献
4.
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
5.
Results from an experimental study on the delamination of a unidirectional carbon fiber/epoxy composite by using the four-point
bend end-notched flexure (4ENF) test are presented. It was found that the compliance data obtained in load-unload-reload and
continuous loading tests were very similar. The R-curves for specimens of different thickness were also found experimentally.
These curves showed an appreciable toughening with crack advance, which can be explained by the presence of fiber bridging.
The finite-element method with cohesive elements allowing us to model the progressive delamination was used to analyze the
4ENF test.
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Russian translated published in Mekhanika Kompozitnykh Materialov, Vol. 41, No. 5, pp. 573–584, September–October, 2005. 相似文献
6.
Yu. M. Pleskachevskii A. O. Shimanovskii G. M. Kuzemkina 《Mechanics of Composite Materials》2008,44(3):209-214
A finite-element model of a reinforced concrete beam with rebars modeled by a 3-D deformable body has been developed. An analysis
of the stress-strain state of the beam allowed us to determine the stress distribution on cross sections of the rebars and
the location of zones with cracks in concrete. It is found that the break of bond between the reinforcement and concrete goes
outside the areas of intensely cracked concrete matrix.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 44, No. 3, pp. 309–316, May–June, 2008. 相似文献
7.
A two-scale model for predicting the multiple crack growth in viscoelastic solids due to an impact is presented. The cracks
are considered only at the local scale through the use of a micromechanical viscoelastic cohesive zone model. The multiscale
model has been implemented in a finite-element code. In order to minimize the computation time, the local finite-element meshes
are solved in parallel by multiple processors. An example problem is given in order to demonstrate the capabilities of the
model.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 45, No. 2, pp. 211–222, March–April, 2009. 相似文献
8.
The elastoplastic stress state of a laminated stainless-steel-fiber-reinforced aluminum-matrix plates, with or without a hole,
subjected to a pressure on their top is examined by using the finite-element method. The analysis is carried out for three
layouts: (0/90/0/90)s, (45/-45/45/-45)s, and (30/60/30/60)s. The Newton-Raphson method is used to solve the nonlinear problem. The distributions of equivalent stresses and the plastic
zones of the plates without a hole and with a hole of various diameters are determined.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 42, No. 4, pp. 531–544, July–August, 2006. 相似文献
9.
With the use of the finite-element method, the generalized plane stressed state of a rectangle of isotropic functionally gradient
materials under the action of normal load is investigated. A finite-element model is constructed by the Bubnov–Galerkin method.
The domain of the body is split into rectangular gradient elements that take into account dependences of Young’s modulus and
Poisson’s ratios on coordinates. Numerical calculations are performed for the case where Young’s modulus is a polynomial function.
The influence of the material gradientness and the sizes of the rectangle on its stress-strain state is analyzed. 相似文献
10.
A. Yousfia S. Fréour F. Jacquemin M. Rahmani H. Osmani R. Guillén 《Mechanics of Composite Materials》2010,46(1):101-112
The mechanical behavior of carbon-fiber-reinforced polymer matrix composites having undergone a thermo-oxidation process is
studied. The purpose is to perform a multiscale analysis of the consequences of oxidation on the intrinsic mechanical properties
of the external composite ply and on the internal mechanical states experienced by the structure under mechanical loads. The
effective mechanical properties of oxidized composite plies are determined according to the Eshelby–Kr?ner self-consistent
homogenization procedure, depending on evolution of the oxidation process. The results obtained are compared with estimates
found by the finite-element method. The macroscopic mechanical states are calculated for a unidirectional composite and laminates.
The macroscopic stresses in each ply of the structure are determined by the classical lamination theory and the finite-element
method, whereas the local stresses in the carbon fiber and epoxy matrix are calculated by using an analytical stress concentration
relation. 相似文献
11.
The purpose of this study is to describe the interfacial interactions in terms of stress distributions on short fibers in
fiber-matrix unit-cell models. The fiber and matrix are subjected to tensile loading. The study consists of three main parts.
First, fiber-matrix cell segments are modeled using a 3D finite-element analysis (FEA) with ANSYS. Three different finite-element
geometrical unit-cell models are generated in order to simulate the Cox analytical model: a fiber-matrix combination, a single
fiber, and a single matrix element. The second part contains the results of 3D FE analyses, which are applied to the Cox formulations
by using a computer program developed. In the last part, the analytical solutions for distributions of normal and shear stresses
are investigated. Cox 2D linear elasticity solutions, together with finite-element ones, are presented in detail in graphs.
The interfacial interactions between the fibers and matrix are also discussed considering the relative changes in the distributions
of normal and shear stresses.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 44, No. 4, pp. 505–520, July–August, 2008. 相似文献
12.
The paper deals with evaluation of the bond performance between a CFRP plate and concrete with respect to various compressive
strengths of concrete and bond lengths of the CFRP plate as parameters. To consider stress conditions in the tensile zone
of reinforced concrete (RC) structures, double-lap axial tension tests were conducted for eight specimens with CFRP plates
bonded to concrete prisms. In addition, a simple linear bond-slip model for the CFRP plate/concrete joints, developed from
the bond tests, was used. To verify the model proposed, a total of seven RC beams were strengthened with CFRP plates and tested
in flexure employing various bond lengths, strengthening methods, and numbers of CFRP plates. A nonlinear finite-element analysis,
with the bond–slip model incorporated in the DIANA program, was performed for the strengthened RC beams. Also, the results
of flexural test and analytical predictions are found to be in close agreement in terms of yield and ultimate loads and ductility. 相似文献
13.
Xiaoqing Yan Shurong Ding J. W. Tong M. Shen Z. Huo 《Mechanics of Composite Materials》2009,45(3):293-302
A thermoplastic angle-ply AS4/PEEK laminate with a hole is considered. The interlaminar stresses along the hole edge at different
interfaces under uniaxial extension are investigated. According to the symmetries of the structure and loading, a suitable
finite-element model is developed. Utilizing a three-dimensional elastic-plastic finite-element procedure elaborated previously,
a finite-element modeling of the interlaminar stresses in a thick angle-ply composite laminate is carried out. Based on the
interlaminar stresses obtained, the dangerous locations of delamination initiation are predicted. The results obtained indicate
that there is some relationship between the dangerous locations and fiber orientations in the adjacent layers, and it maybe
inferred that the critical locations are near the regions where the hole edge is tangent to the fiber orientation in the layers
adjacent to the interface. The interlaminar stresses at the same interfaces are not sensible to distances from the midplane
of the laminate. Very high interlaminar tensile stresses are found to exist on the hole edge at the +25°/+25° or –25°/–25°
interfaces, and delaminations can initiate there first.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 45, No. 3, pp. 427-440, May-June, 2009. 相似文献
14.
A. Naceri 《Mechanics of Composite Materials》2007,43(5):403-408
An analysis of the mechanical and acoustic responses of a laminate composed of 12 layers of glass fiber fabric/epoxy resin
and conditioned in environments with relative humidities of 0, 60, and 96% RH at 60°C is presented. The first part of the
study consists in following the weight gain according to the duration of hygrothermal conditioning, and the second part—in
test ing 45°-oriented specimens in uniaxial tension up to failure at constant imposed displacement rates, with registrating
the acoustic emission to track the damage process. The influence of moisture content in the material showed up as a significant
decrease in its shear modulus, shear stress, and acoustic emission with growing quantity of absorbed water. An exponential
function is proposed for describing the relationship between the varying shear modulus and the shear strain.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 43, No. 5, pp. 595–602, September–October, 2007. 相似文献
15.
The main focus of the present paper is the estimation of the macroscopic stress–strain behavior of a particulate composite.
A composite with a cross-linked polymer matrix in a rubbery state filled with an alumina-based mineral filler is investigated
by means of the finite-element method. The hyperelastic material behavior of the matrix is described by the Mooney–Rivlin
material model. Numerical models on the basis of unit cells are developed. The existence of a discontinuity (breaking) in
the matrix at higher loading levels is taken into account to obtain a more accurate estimate for the stress–strain behavior
of the particulate composite investigated. The numerical results obtained are compared with an experimental stress–strain
curve, and a good agreement is found to exist. The paper can contribute to a better understanding of the behavior and failure
of particulate composites with a polymer matrix. 相似文献
16.
We propose a computational model for determining the residual stresses in a welded glass structure taking account of the properties
of the formation of residual stresses in glass. The problem is solved in displacements using Galerkin's method in conjunction
with a finite-element model. A numerical solution is obtained for the axisymmetric case.
Translated fromMatematichni Metodi ta Fiziko-mekhanichni Polya, Vol. 39, No. 1, 1996, pp. 131–134. 相似文献
17.
The strength and fracture mechanism of the contact zone between a carbon-fiber-reinforced plastic (CFRP) and concrete in flexural
structural elements is investigated. Two methods for calculating the shear force in the contact zone are considered, one of
which takes into account the compliance of the zone and gives results agreeing rather well with experimental data for beams,
regardless of the way the CFRP is fastened to concrete. The method of shear stresses is good for beams with in significant
shear strains between CFRP and concrete. A method allowing for hardening of the contact zone is suggested. It is shown that
the fracture mechanism of the zone depends on the way of fastening the CFRP and the depth the adhesive penetrates into concrete.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 43, No. 5, pp. 687–700, September–October, 2007. 相似文献
18.
Gatica Gabriel N.; Meddahi Salim; Oyarzua Ricardo 《IMA Journal of Numerical Analysis》2009,29(1):86-108
19.
With the use of an analytical approach developed, the influence of distribution of a tangential load on the stress concentration
in uniaxially tensioned flat specimens of high-strength unidirectional composites near the grips of a testing machine is evaluated.
In view of singularity of the analytical solution derived at the points of discontinuity of boundary conditions, for estimating
the stress concentration, it is suggested to employ the averaged value of longitudinal stresses, which is calculated by means
of an improper integral across the thickness of a near-surface layer.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 6, pp. 787–796, November–December, 2006. 相似文献
20.
B. D. Drobenko V. I. Astashkin I. I. Chupik A. P. Bukalov 《Journal of Mathematical Sciences》1996,79(6):1431-1433
We use the finite-element method to study the problem of determining the temperature field and the evolution of the phase-state
regions in a hollow cylindrical casting. Using weighted discrepancies we reduce the problem to solving systems of ordinary
differential equations. We give a model solution of a specific problem and detailed analysis of the results.
Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, No. 37, 1994, pp. 55–57. 相似文献