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Vasyliovych Volodymyr Loboda - One of the best experts on this subject based on the ideXlab platform.

  • On a Moving interface crack with a contact zone in a piezoelectric bimaterial
    International Journal of Solids and Structures, 2005
    Co-Authors: K. P. Herrmann, Anatolevich Valerij Komarov, Vasyliovych Volodymyr Loboda
    Abstract:

    Abstract An inplane problem for a crack Moving with constant subsonic speed along the interface of two piezoelectric materials is considered. A mechanically frictionless and electrically permeable contact zone is assumed at the right crack tip whilst for the open part of the crack both electrically permeable and electrically insulated conditions are considered. In the first case a Moving concentrated loading is prescribed at the crack faces and in the second case an additional electrical charge at the crack faces is prescribed as well. The main attention is devoted to electrically permeable crack faces. Introducing a Moving Coordinate System at the leading crack tip the corresponding inhomogeneous combined Dirichlet–Riemann problem is formulated and solved exactly for this case. All electromechanical characteristics at the interface are presented in a closed form for arbitrary contact zone lengths, and further, the transcendental equation for the determination of the real contact zone length is derived. As a particular case of the obtained solution a semi-infinite crack with a contact zone is considered. The numerical analysis performed for a certain piezoelectric bimaterial showed an essential increase of the contact zone length and the associated stress intensity factor especially for the near-critical speed region. Similar investigations have been performed for an electrically insulated crack and the same behavior of the above mentioned parameters is observed.

  • Static and extending interface cracks with contact zones in anisotropic as well as in piezoelectric bimaterials
    Pamm, 2003
    Co-Authors: K. P. Herrmann, Vasyliovych Volodymyr Loboda
    Abstract:

    An interface crack with an electrically permeable and mechanically frictionless contact zone in a piezoelectric bimaterial under the action of a remote mixed mode mechanical loading as well as thermal and electrical fields is considered in the first part of this paper. By use of the matrix-vector representations of thermal, mechanical and electrical fields via sectionally-holomorphic functions the problems of linear relationships are formulated and solved exactly both for an electrically permeable and an electrically impermeable interface crack. For these cases the transcendental equations and clear analytical formulas are derived for the determination of the contact zone lengths and the associated fracture mechanical parameters. A plane strain problem for a crack with a frictionless contact zone at the leading crack tip extending stationary along an interface of two semi-infinite anisotropic spaces with a subsonic speed under the action of various loading is considered in the second part of this paper. By introducing of a Moving Coordinate System connected with the crack tip and by using the formal similarity of static and propagating crack problems the combined Dirichlet-Riemann boundary value problem is formulated and solved exactly for this case as well and a transcendental equation is obtained for the determination of the real contact zone length. It is found that the increase of the crack speed leads to an increase of the real contact zone length and the correspondent stress intensity factors which increase significantly for a quasi-Rayleigh wave speed.

Serge V Koshelev - One of the best experts on this subject based on the ideXlab platform.

  • mag two dimensional resistive mhd code using an arbitrary Moving Coordinate System
    Computer Physics Communications, 1997
    Co-Authors: Oleg V Diyankov, Igor V Glazyrin, Serge V Koshelev
    Abstract:

    Abstract The MAG code used for two-dimensional magnetohydrodynamics flow modelling is described. MAG algorithms are formulated for an arbitrary Moving Coordinate System. MAG can calculate flows with large deformations contained inside a region whose weakly deformed boundaries maintain the correct description of boundary conditions. Numerical experiments with two-dimensional MHD flows calculations show that the proposed numerical schemes are quite robust and accurate. Sample calculations illustrating the properties of the algorithms are presented.

  • mag two dimensional radiation resistive mhd code using arbitrary Moving Coordinate System
    International Conference on Plasma Science, 1997
    Co-Authors: Oleg V Diyankov, Igor V Glazyrin, Serge V Koshelev, N P Savina
    Abstract:

    Summary form only given, as follows. The MAG code for the 2D radiative plasma flows in magnetic field is presented. The algorithm has been formulated for an arbitrary Moving Coordinate System. The code has some interesting features, which allow to simulate MHD plasma flows with large deformations inside the flow region, conserving the correct description of its weakly deformated boundaries. The model, realized in the code, contains terms for the description of the following phenomena: spontaneous magnetic fields, Hall effect, magnetizing of transport coefficients, kinetics of ionization, radiation transfer. The code has been used for inertial fusion modeling and plasma liners implosion modeling.

Oleg V Diyankov - One of the best experts on this subject based on the ideXlab platform.

  • mag two dimensional resistive mhd code using an arbitrary Moving Coordinate System
    Computer Physics Communications, 1997
    Co-Authors: Oleg V Diyankov, Igor V Glazyrin, Serge V Koshelev
    Abstract:

    Abstract The MAG code used for two-dimensional magnetohydrodynamics flow modelling is described. MAG algorithms are formulated for an arbitrary Moving Coordinate System. MAG can calculate flows with large deformations contained inside a region whose weakly deformed boundaries maintain the correct description of boundary conditions. Numerical experiments with two-dimensional MHD flows calculations show that the proposed numerical schemes are quite robust and accurate. Sample calculations illustrating the properties of the algorithms are presented.

  • mag two dimensional radiation resistive mhd code using arbitrary Moving Coordinate System
    International Conference on Plasma Science, 1997
    Co-Authors: Oleg V Diyankov, Igor V Glazyrin, Serge V Koshelev, N P Savina
    Abstract:

    Summary form only given, as follows. The MAG code for the 2D radiative plasma flows in magnetic field is presented. The algorithm has been formulated for an arbitrary Moving Coordinate System. The code has some interesting features, which allow to simulate MHD plasma flows with large deformations inside the flow region, conserving the correct description of its weakly deformated boundaries. The model, realized in the code, contains terms for the description of the following phenomena: spontaneous magnetic fields, Hall effect, magnetizing of transport coefficients, kinetics of ionization, radiation transfer. The code has been used for inertial fusion modeling and plasma liners implosion modeling.

K. P. Herrmann - One of the best experts on this subject based on the ideXlab platform.

  • On a Moving interface crack with a contact zone in a piezoelectric bimaterial
    International Journal of Solids and Structures, 2005
    Co-Authors: K. P. Herrmann, Anatolevich Valerij Komarov, Vasyliovych Volodymyr Loboda
    Abstract:

    Abstract An inplane problem for a crack Moving with constant subsonic speed along the interface of two piezoelectric materials is considered. A mechanically frictionless and electrically permeable contact zone is assumed at the right crack tip whilst for the open part of the crack both electrically permeable and electrically insulated conditions are considered. In the first case a Moving concentrated loading is prescribed at the crack faces and in the second case an additional electrical charge at the crack faces is prescribed as well. The main attention is devoted to electrically permeable crack faces. Introducing a Moving Coordinate System at the leading crack tip the corresponding inhomogeneous combined Dirichlet–Riemann problem is formulated and solved exactly for this case. All electromechanical characteristics at the interface are presented in a closed form for arbitrary contact zone lengths, and further, the transcendental equation for the determination of the real contact zone length is derived. As a particular case of the obtained solution a semi-infinite crack with a contact zone is considered. The numerical analysis performed for a certain piezoelectric bimaterial showed an essential increase of the contact zone length and the associated stress intensity factor especially for the near-critical speed region. Similar investigations have been performed for an electrically insulated crack and the same behavior of the above mentioned parameters is observed.

  • Static and extending interface cracks with contact zones in anisotropic as well as in piezoelectric bimaterials
    Pamm, 2003
    Co-Authors: K. P. Herrmann, Vasyliovych Volodymyr Loboda
    Abstract:

    An interface crack with an electrically permeable and mechanically frictionless contact zone in a piezoelectric bimaterial under the action of a remote mixed mode mechanical loading as well as thermal and electrical fields is considered in the first part of this paper. By use of the matrix-vector representations of thermal, mechanical and electrical fields via sectionally-holomorphic functions the problems of linear relationships are formulated and solved exactly both for an electrically permeable and an electrically impermeable interface crack. For these cases the transcendental equations and clear analytical formulas are derived for the determination of the contact zone lengths and the associated fracture mechanical parameters. A plane strain problem for a crack with a frictionless contact zone at the leading crack tip extending stationary along an interface of two semi-infinite anisotropic spaces with a subsonic speed under the action of various loading is considered in the second part of this paper. By introducing of a Moving Coordinate System connected with the crack tip and by using the formal similarity of static and propagating crack problems the combined Dirichlet-Riemann boundary value problem is formulated and solved exactly for this case as well and a transcendental equation is obtained for the determination of the real contact zone length. It is found that the increase of the crack speed leads to an increase of the real contact zone length and the correspondent stress intensity factors which increase significantly for a quasi-Rayleigh wave speed.

Hakan Akyildiz - One of the best experts on this subject based on the ideXlab platform.

  • a numerical study of the effects of the vertical baffle on liquid sloshing in two dimensional rectangular tank
    Journal of Sound and Vibration, 2012
    Co-Authors: Hakan Akyildiz
    Abstract:

    Abstract The liquid sloshing in a Moving partially filled rectangular tank with a vertical baffle is investigated. A numerical algorithm based on the volume of fluid (VOF) technique is used to study the nonlinear behavior of liquid sloshing. The numerical model solves the complete Navier–Stokes equations in primitive variables by using of finite difference approximations with the Moving Coordinate System. The ratio of baffle height to the initial liquid depth has been changed in the range of 0≤ h B / h ≤1.2. The critical baffle height to reach the roof of the tank and the baffle height beyond the liquid does not get over the baffle anymore have been investigated. The vortex originated by the flow separation from the baffle tip became weaker with increasing the baffle height. In order to assess the accuracy of the method used, some results with baffle height are compared with the experimental results. Comparisons show good agreement for slosh loads in the cases investigated. The free surface elevation and the time variations of pressures have been also presented.

  • Sloshing in a three-dimensional rectangular tank: Numerical simulation and experimental validation
    Ocean Engineering, 2006
    Co-Authors: Hakan Akyildiz, N. Erdem Unal
    Abstract:

    Abstract Pressure variations and three-dimensional effects on liquid sloshing loads in a Moving partially filled rectangular tank have been carried out numerically and experimentally. A numerical algorithm based on the volume of fluid (VOF) technique is used to study the non-linear behavior and damping characteristics of liquid sloshing. A Moving Coordinate System is used to include the non-linearity and avoid the complex boundary conditions of Moving walls. The numerical model solves the complete Navier–Stokes equations in primitive variables by using of the finite difference approximations. In order to mitigate a series of discrete impacts, the signal computed is averaged over several time steps. In order to assess the accuracy of the method used, computations are compared with the experimental results. Several configurations of both baffled and unbaffled tanks are studied. Comparisons show good agreement for both impact and non- impact type slosh loads in the cases investigated.

  • Numerical Computation of Hydrodynamic Loads on Walls of a Rigid Rectangular Tank Due to Large Amplitude Liquid Sloshing
    Turkish Journal of Engineering and Environmental Sciences, 2002
    Co-Authors: Hakan Akyildiz, M. Serdar Celebi
    Abstract:

    Liquid sloshing in a Moving partially filled rectangular tank have been investigated. Sloshing in a rectangular tank is a non-linear phenomenon. When the amplitude of tank oscillation is large, two types of non-linearities are present. One occurs at the free surface due to the large fluid motion. The other occurs at the fluid-tank interface. A numerical algorithm based on the volume of fluid (VOF) technique is used to study the non-linear behavior and damping characteristics of liquid sloshing in partially filled rectangular tanks subjected to large amplitude excitation. The excitation is assumed to be harmonic to simulate tank motion. The fluid is assumed to be homogeneous, isotropic, viscous, and Newtonian and exhibits only limited compressibility. Tank and fluid motions are assumed to be two-dimensional. A Moving Coordinate System is used to include the non-linearity and avoid the complex boundary conditions of Moving walls. The numerical model solves the complete Navier-Stokes equations in primitive variables by using of the finite difference approximations. The VOF technique is used to track the free surface and, at each time step, a donar-acceptor method is used to transport the volume of fluid function and hence the locations of the free surface. The numerical method also allows the interaction of the fluid with the tank top. In order to assess the accuracy of the method used, computations are compared with the experimental results. Comparisons show good agreement for both impact and non- impact type slosh loads in the cases investigated.