The Experts below are selected from a list of 117 Experts worldwide ranked by ideXlab platform

Q Wang - One of the best experts on this subject based on the ideXlab platform.

  • buckling and vibration analysis of a pressurized cnt reinforced functionally graded truncated conical shell under an axial compression using hdq method
    Computer Methods in Applied Mechanics and Engineering, 2016
    Co-Authors: M Mehri, Hamed Asadi, Q Wang
    Abstract:

    Abstract The present research deals with bifurcation and vibration responses of a composite truncated conical shell with embedded single-walled carbon nanotubes (SWCNTs) subjected to an external pressure and axial compression simultaneously. The distribution of reinforcements through the thickness of the shell is assumed to be either uniform or functionally graded. The equations of motion are established using Green–Lagrange type nonlinear kinematics within the framework of Novozhilov nonlinear shell theory. Linear membrane Prebuckling analysis is conducted to extract the Prebuckling deformations. The stability equations are derived by applying the adjacent equilibrium criterion to the Prebuckling State of the conical shell. A semi-analytical solution on the basis of the trigonometric expansion through the circumferential direction along with the harmonic differential quadrature (HDQ) discretization in the meridional direction is developed. A series of comparison studies are carried out to assure the accuracy and the convergence of the HDQ method. The research indicates that the superb accuracy and efficiency of solutions with few grid points are attributed to the higher-order harmonic approximation function in the HDQ method. Parametric studies are also presented to investigate the influence of boundary conditions, semi-vertex angle of the cone, volume fraction and distribution of CNTs on stability and vibration characteristics of the truncated conical shell. The results show that both volume fraction and distribution of CNTs play a pivotal role in the natural frequencies, buckling mode and buckling loads of the FG-CNTRC truncated conical shell.

Jorn S. Hansen - One of the best experts on this subject based on the ideXlab platform.

  • Mode Interaction of Axially Stiffened Cylindrical Shells: Effects of Stringer Axial Stiffness, Torsional Rigidity,
    2016
    Co-Authors: David Hui, R. C. Tennyson, Assoc Mem Asme, Jorn S. Hansen
    Abstract:

    This paper deals with the effect of stringer axial stiffness, torsional rigidity, and eccen-tricity on the panel initial postbuckling behavior and mode interaction of axially stiffened cylindrical shells. As far as the local panel mode is concerned, the cylinder is taken to be integrally stiffened and the postbuckling redistribution of the axial load-carrying capaci-ty between the skin and stringers is investigated. It is found that although the buckling analysis is more or less identical to previous analyses, there are significant changes in the quartic term of the potential energy of the local mode and hence, the imperfection-sensi-tivity of the structure is altered. These changes are due to the interaction between the stringers and the skin in the postbuckling analysis. In addition, to assess the effect of a nonlinear Prebuckling State resulting from the presence of local imperfections, Koiter's theory of amplitude modulation of the local mode is applied to an example problem of in-terest

Golovanov A. - One of the best experts on this subject based on the ideXlab platform.

  • Stress-strain State and stability of composite sandwich shells with a scaling zone between the core and facings
    1994
    Co-Authors: Golovanov A.
    Abstract:

    A finite element model is presented for analyzing the strength and stability of sandwich shells of arbitrary configuration with an adhesion failure zone between the core and one of the facings. The model is based on the assumptions that both facings are laminated Timoshenko-type composite shells, only transverse shear stresses in the core and normal stresses in the thickness direction have nonzero values, a free slip in the tangential plane in the adhesion failure zone and unilateral contact along the normal are possible, and the Prebuckling State in the stability problem is linear. Biquadratic nine-node approximations for all functions and numerical integration were used. The displacements and rotation angles of the normals toward the facings as well as stresses in the core are taken as global degrees of freedom. The algebraic problem is solved using a special step-by-step procedure of determining the contact area in the scaling zone and employing unilateral constraints for some of the unknowns. Numerical examples are also given. © 1994 Plenum Publishing Corporation

  • Stress-strain State and stability of composite sandwich shells with a scaling zone between the core and facings
    1993
    Co-Authors: Golovanov A.
    Abstract:

    A finite element model is presented for analysing the strength and stability of sandwich shells of arbitrary configuration with an adhesion failure zone between the core and one of the facings. The model is based on the following assumptions: both facings are laminated Timoshenko-type composite shells; in the core only transverse shear stresses and normal stresses in the thickness direction have non-zero values; in the adhesion failure zone a free slip in the tangential plane, and a unilateral contact along the normal are possible; in the stability problem the Prebuckling State is assumed to be linear. Displacements and rotation angles of the normals towards the facings, as well as stresses in the core are taken as global degrees of freedom. The algebraic problem is solved by using a special step-by-step procedure of determining the contract area in the scaling zone and employing unilateral restrictions to some of the unknowns. Numerical examples are also given

V. N. Paimushin - One of the best experts on this subject based on the ideXlab platform.

  • Non-uniformly scaled buckling modes of reinforcing elements in fiber reinforced plastic
    Russian Mathematics, 2017
    Co-Authors: V. N. Paimushin, N. V. Polyakova, S. A. Kholmogorov, M. S. Shishov
    Abstract:

    We consider a problem about non-uniformly scaled buckling modes of isolated fiber (without accounting of interaction with the surrounding epoxy) or bundle of fibers, which are structural elements of fiber reinforced plastics under the transverse tension (compression) and shear stresses in Prebuckling State. Such initial State is formed in fibers and bundles of fibers at tension-compression tests of flat specimens from cross ply composites with unidirectional fibers. For problem Statement we use equations recently constructed by reduction of consistent version of geometrically nonlinear equations of theory of elasticity to one dimensional equations of rectilinear beams. Equations are based on refined shear S. P. Timoshenko model with accounting of tension-compression stresses in transverse directions. We give theoretical explanation of developed phenomenon as reducing shear modulus of elasticity of fiber reinforced plastic during the increasing of shear strains. We show that under the loading process of specimens under review uninterruptedly structure reconstruction of composite trough implementation and uninterruptedly changing of internal buckling modes at changing wave parameter is feasible.

  • Stress-strain State and stability of composite sandwich shells with a scaling zone between the core and facings
    Mechanics of Composite Materials, 1994
    Co-Authors: A. I. Golovanov, V. N. Paimushin
    Abstract:

    A finite element model is presented for analyzing the strength and stability of sandwich shells of arbitrary configuration with an adhesion failure zone between the core and one of the facings. The model is based on the assumptions that both facings are laminated Timoshenko-type composite shells, only transverse shear stresses in the core and normal stresses in the thickness direction have nonzero values, a free slip in the tangential plane in the adhesion failure zone and unilateral contact along the normal are possible, and the Prebuckling State in the stability problem is linear. Biquadratic nine-node approximations for all functions and numerical integration were used. The displacements and rotation angles of the normals toward the facings as well as stresses in the core are taken as global degrees of freedom. The algebraic problem is solved using a special step-by-step procedure of determining the contact area in the scaling zone and employing unilateral constraints for some of the unknowns. Numerical examples are also given.

David Hui - One of the best experts on this subject based on the ideXlab platform.

  • Mode Interaction of Axially Stiffened Cylindrical Shells: Effects of Stringer Axial Stiffness, Torsional Rigidity,
    2016
    Co-Authors: David Hui, R. C. Tennyson, Assoc Mem Asme, Jorn S. Hansen
    Abstract:

    This paper deals with the effect of stringer axial stiffness, torsional rigidity, and eccen-tricity on the panel initial postbuckling behavior and mode interaction of axially stiffened cylindrical shells. As far as the local panel mode is concerned, the cylinder is taken to be integrally stiffened and the postbuckling redistribution of the axial load-carrying capaci-ty between the skin and stringers is investigated. It is found that although the buckling analysis is more or less identical to previous analyses, there are significant changes in the quartic term of the potential energy of the local mode and hence, the imperfection-sensi-tivity of the structure is altered. These changes are due to the interaction between the stringers and the skin in the postbuckling analysis. In addition, to assess the effect of a nonlinear Prebuckling State resulting from the presence of local imperfections, Koiter's theory of amplitude modulation of the local mode is applied to an example problem of in-terest