The Experts below are selected from a list of 25245 Experts worldwide ranked by ideXlab platform
S D Akbarov - One of the best experts on this subject based on the ideXlab platform.
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torsional wave propagation in a pre stressed circular cylinder embedded in a pre stressed elastic medium
Applied Mathematical Modelling, 2009Co-Authors: A Ozturk, S D AkbarovAbstract:Within the framework of the piecewise homogeneous body model with utilization of the three-dimensional Linearized Theory of elastic waves in initially stressed bodies, the mathematical modeling of the torsional wave propagation in the initially stressed infinite body containing an initially stressed circular solid cylinder (case 1) and circular hollow cylinder (case 2) are proposed. In these cases, it has been assumed that in the constituents of the considered systems there exist only the normal homogeneous tensional or compressional initial stress acting along the cylinder, i.e. in the direction of wave propagation. In the case where the mentioned initial stresses are not present, the proposed mathematical modeling coincides with that proposed and investigated by other authors within the classical linear Theory of elastic waves. The mechanical properties of the cylinder and surrounding infinite medium have been described by the Murnaghan potential. The numerical results related to the torsional wave dispersion and the influence of the mentioned initial stresses on this dispersion are presented and discussed.
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interaction between two neighboring circular holes in a prestretched simply supported orthotropic strip under bending
Mechanics of Composite Materials, 2008Co-Authors: Nazmiye Yahnioglu, S D Akbarov, Babuscu U YesilAbstract:In this work, the influence of initial stretching of a simply supported plate-strip containing two circular holes on the stress concentration around the holes caused by bending of the strip is examined using the finite-element method. The mathematical formulation of the corresponding boundary-value problem is presented within the frame work of the three-dimensional Linearized Theory of elasticity (TDLTE) under a plane strain state. The material of the plate-strip is linearly elastic, homogeneous, and orthotropic. The numerical results obtained in investigating the influence of the initial stretching and the location of holes on the stress concentration are presented. In particular, it is established that the initial stretching significantly decreases the stress concentration at some characteristic points on the contour of the holes.
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on the influence of singular type finite elements on the critical force in studying the buckling of a circular plate with a crack
International Applied Mechanics, 2007Co-Authors: S D Akbarov, Nazmiye Yahnioglu, O G RzayevAbstract:The axisymmetric buckling (delamination) of a circular disk (plate) with a penny-shaped crack is analyzed using a continuum model, piecewise-homogeneous model, and the three-dimensional Linearized Theory of stability. The FEM is used. The analysis is carried out using various singular and ordinary finite elements. The numerical results obtained indicate that it is not necessary to use singular finite elements to solve the problem
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the axisymmetric lamb s problem for a finite prestrained half space covered with a finite prestretched layer
International Applied Mechanics, 2007Co-Authors: S D AkbarovAbstract:The piecewise-homogeneous body model and the three-dimensional Linearized Theory of elastic waves in prestressed bodies are used to solve the axisymmetric time-harmonic Lamb’s problem for a finite prestrained half-space covered with a finite prestretched layer. It is assumed that the half-space and layer are incompressible and their deformation is described by the Treloar potential. The normal stress at the interface is calculated
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the influence of the third order elastic constants to the generalized rayleigh wave dispersion in a pre stressed stratified half plane
International Journal of Engineering Science, 2003Co-Authors: S D Akbarov, Muslum OzisikAbstract:Within the framework of the piecewise homogeneous body model with the use of the three-dimensional Linearized Theory of elasticity the influence of the third order elastic constants on the velocity of the generalized Rayleigh wave propagation in a pre-stressed stratified half-plane is investigated. Between the layer and half-plane the complete contact conditions are satisfied. The concrete numerical investigations are made on the various materials for which the values of the third order elastic constants are known. The initial stresses are determined within the framework of the classical linear Theory of elasticity.
Surkay D Akbarov - One of the best experts on this subject based on the ideXlab platform.
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torsional wave dispersion in a finitely pre strained hollow sandwich circular cylinder
Journal of Sound and Vibration, 2011Co-Authors: Surkay D Akbarov, Tamer Kepceler, Mert M EgilmezAbstract:This paper studies torsional wave dispersion in a three-layered (sandwich) hollow cylinder with finite initial strains. The investigations are carried out within the scope of the piecewise homogeneous body model with the use of the three-dimensional Linearized Theory of elastic waves in initially stressed bodies. The mechanical relations of the materials of the cylinders are described through their harmonic potential. The analytical expression is obtained for the low wavenumber limit values of the torsional wave propagation velocity. The numerical results on the influence of the initial stretching or compression of the cylinders along the torsional wave propagation direction are presented and discussed.
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time harmonic dynamical stress field in a system comprising a pre stressed orthotropic layer and pre stressed orthotropic half plane
Archive of Applied Mechanics, 2010Co-Authors: Surkay D Akbarov, Nihat IlhanAbstract:The time-harmonic dynamical stress field in a system comprising a pre-stressed orthotropic layer and orthotropic half-plane is studied within the scope of the piecewise homogeneous body model utilizing the three-dimensional Linearized Theory of elastic waves in an initially stressed body. The main focus is on the influence of the mechanical properties of the constituent materials and the initial stresses present on the “resonance” values of the normal stress acting on the interface plane and on the “resonance” values of the frequency of the external point-located force. The numerical results are presented and discussed. In particular, it is shown that the values of the normal stress decrease with a decrease in the modulus of elasticity of the materials along the thickness of the covering layer.
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the influence of the finite initial strains on the axisymmetric wave dispersion in a circular cylinder embedded in a compressible elastic medium
International Journal of Mechanical Sciences, 2010Co-Authors: Surkay D Akbarov, M S GulievAbstract:The influence of the finite initial strains on the axisymmetric wave dispersion in a circular cylinder embedded in a compressible elastic medium is investigated within the scope of a piecewise homogeneous body model utilizing three-dimensional Linearized Theory of wave propagation in an initially stressed body. The material of the cylinder and the surrounding elastic medium are assumed to be compressible and the corresponding elasticity relations are described by the harmonic potential. The numerical results are presented and discussed. It is established that the dispersion curves are divided into four parts by the characteristic nondispersive wave velocities regarding the cylinder and the surrounding materials. As a result of the existence of the initial strains the lengths of these parts change and they move wholly up (down) under initial stretching (compressing) strain along the cylinder, i.e. along the wave propagation direction.
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the influence of the third order elastic constants on the dynamical interface stress field in a half space covered with a pre stretched layer
International Journal of Non-linear Mechanics, 2006Co-Authors: Surkay D AkbarovAbstract:Abstract The influence of the third order elastic constants on the dynamical (time-harmonic) axisymmetric interface stress field in the system which comprises the half-space and the pre-stretched covering layer is investigated within the framework of the piecewise homogeneous body model by employing the three-dimensional Linearized Theory of elastic waves in initially stressed bodies. The elasticity relations for the layer and half-space materials are given through the Murnaghan potential. It is assumed that the force acting on the free face plane of the covering layer is a time-harmonic point-located normal force. The influences due to both of the quantities of the pre-stretching of the layer and the third order elastic constants of the layer material on the interface normal stress are analysed. The numerical results are presented for concrete selected materials such as steel, aluminium and acrylic plastic.
Nazmiye Yahnioglu - One of the best experts on this subject based on the ideXlab platform.
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interaction between two neighboring circular holes in a prestretched simply supported orthotropic strip under bending
Mechanics of Composite Materials, 2008Co-Authors: Nazmiye Yahnioglu, S D Akbarov, Babuscu U YesilAbstract:In this work, the influence of initial stretching of a simply supported plate-strip containing two circular holes on the stress concentration around the holes caused by bending of the strip is examined using the finite-element method. The mathematical formulation of the corresponding boundary-value problem is presented within the frame work of the three-dimensional Linearized Theory of elasticity (TDLTE) under a plane strain state. The material of the plate-strip is linearly elastic, homogeneous, and orthotropic. The numerical results obtained in investigating the influence of the initial stretching and the location of holes on the stress concentration are presented. In particular, it is established that the initial stretching significantly decreases the stress concentration at some characteristic points on the contour of the holes.
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on the stress distribution in a prestretched simply supported strip containing two neighboring circular holes under forced vibration
International Applied Mechanics, 2007Co-Authors: Nazmiye YahniogluAbstract:The three-dimensional Linearized Theory of elastic waves in initially stressed bodies under plane strain is used to study the influence of the initial stretching of a simply supported plate strip with two neighboring circular holes on the stress concentration around the holes caused by additional uniformly distributed dynamic (time-harmonic) normal forces acting on the upper face. The corresponding problem is formulated and solved by the finite-element method. Numerical results on the stress concentration around the holes and the influence of the initial stretching on this concentration are presented
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on the influence of singular type finite elements on the critical force in studying the buckling of a circular plate with a crack
International Applied Mechanics, 2007Co-Authors: S D Akbarov, Nazmiye Yahnioglu, O G RzayevAbstract:The axisymmetric buckling (delamination) of a circular disk (plate) with a penny-shaped crack is analyzed using a continuum model, piecewise-homogeneous model, and the three-dimensional Linearized Theory of stability. The FEM is used. The analysis is carried out using various singular and ordinary finite elements. The numerical results obtained indicate that it is not necessary to use singular finite elements to solve the problem
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the loss of stability analyses of an elastic and viscoelastic composite circular plate in the framework of three dimensional Linearized Theory
European Journal of Mechanics A-solids, 2003Co-Authors: Zafer Kutug, Nazmiye Yahnioglu, S D AkbarovAbstract:In the present paper, in the framework of three-dimensional Linearized Theory of stability (TDLTS) the statement of the problem of stability loss of a circular plate made from a viscoelastic composite material is suggested. The method for solution to these problems is developed by employing Laplace transform and FEM. It is assumed that the plate has an insignificant initial rotationally symmetrical imperfection. Stability is assumed to be lost when the imperfection starts to increase and grow indefinitely. Numerical results obtained by TDLTS are compared with corresponding results obtained in the framework of the third order refined plate Theory.
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stability loss analyses of the elastic and viscoelastic composite rotating thick circular plate in the framework of the three dimensional Linearized Theory of stability
International Journal of Mechanical Sciences, 2002Co-Authors: Nazmiye Yahnioglu, S D AkbarovAbstract:In the present paper, in the framework of the three-dimensional Linearized Theory of stability the rotationally symmetric stability loss problems of the elastic and viscoelastic composite rotating thick circular and annular discs are investigated. The method for solution to these problems is developed by employing Laplace transform and finite element method. It is supposed that the disc and annular disc have an insignificant rotationally symmetric initial imperfection and as a stability loss criterion, the case where this imperfection starts to increase and grows indefinitely, is taken. Numerical results related to the critical angular velocity for elastic problems and to the critical time for viscoelastic problems are presented.
M S Guliev - One of the best experts on this subject based on the ideXlab platform.
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the influence of the finite initial strains on the axisymmetric wave dispersion in a circular cylinder embedded in a compressible elastic medium
International Journal of Mechanical Sciences, 2010Co-Authors: Surkay D Akbarov, M S GulievAbstract:The influence of the finite initial strains on the axisymmetric wave dispersion in a circular cylinder embedded in a compressible elastic medium is investigated within the scope of a piecewise homogeneous body model utilizing three-dimensional Linearized Theory of wave propagation in an initially stressed body. The material of the cylinder and the surrounding elastic medium are assumed to be compressible and the corresponding elasticity relations are described by the harmonic potential. The numerical results are presented and discussed. It is established that the dispersion curves are divided into four parts by the characteristic nondispersive wave velocities regarding the cylinder and the surrounding materials. As a result of the existence of the initial strains the lengths of these parts change and they move wholly up (down) under initial stretching (compressing) strain along the cylinder, i.e. along the wave propagation direction.
E Montanari - One of the best experts on this subject based on the ideXlab platform.
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exact solution to the homogeneous maxwell equations in the field of a gravitational wave in Linearized Theory
Classical and Quantum Gravity, 1999Co-Authors: Mirco Calura, E MontanariAbstract:We present the exact solution to the Linearized Maxwell equations in spacetime slightly curved by a gravitational wave. We show that in general, even dealing with a first-order Theory in the strength of the gravitational field, the solution cannot be written as the sum of the flat spacetime one and a weak perturbation due to the external field. Such an impossibility arises when either the frequency of the gravitational wave is too low or too high with respect to that of the electromagnetic field. We also provide an application of the solution to the case of an electromagnetic field bounced between two parallel conducting planes.
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exact solution to the homogeneous maxwell equations in the field of a gravitational wave in Linearized Theory
arXiv: General Relativity and Quantum Cosmology, 1998Co-Authors: Mirco Calura, E MontanariAbstract:We present the exact solution to the Linearized Maxwell equations in space-time slightly curved by a gravitational wave. We show that in general, even dealing with a first-order Theory in the strength of the gravitational field, the solution can not be written as the sum of the flat space-time one and a weak perturbation due to the external field. Such an impossibility arises when either the frequency of the gravitational wave is too low or too high with respect to the one of the electromagnetic field. We also provide an application of the solution to the case of an electromagnetic field bounced between two parallel conducting planes.
