The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform

Ashraf M Zenkour - One of the best experts on this subject based on the ideXlab platform.

  • Benchmark trigonometric and 3-D elasticity solutions for an exponentially graded thick rectangular plate
    Archive of Applied Mechanics, 2007
    Co-Authors: Ashraf M Zenkour
    Abstract:

    The bending problem of a transverse load acting on an isotropic inhomogeneous rectangular plate using both two-dimensional (2-D) trigonometric and three-dimensional (3-D) elasticity solutions is considered. In the present 2-D solution, trigonometric terms are used for the displacements in addition to the initial terms of a power series through the thickness. The effects due to transverse shear and normal deformations are both included. The form of the assumed 2-D displacements is simplified by enforcing traction-free boundary conditions at the faces of the plate. No transverse shear correction factors are needed because a correct representation of the transverse Shearing Strain is given. The plate material is exponentially graded, meaning that Lamé’s coefficients vary exponentially in a given fixed direction (the thickness direction). A wide variety of results for the displacements and stresses of an exponentially graded rectangular plate are presented. The validity of the present 2-D trigonometric solution is demonstrated by comparison with the 3-D elasticity solution. The influence of aspect ratio, side-to-thickness ratio and the exponentially graded parameter on the bending response are investigated.

  • benchmark trigonometric and 3 d elasticity solutions for an exponentially graded thick rectangular plate
    Archive of Applied Mechanics, 2007
    Co-Authors: Ashraf M Zenkour
    Abstract:

    The bending problem of a transverse load acting on an isotropic inhomogeneous rectangular plate using both two-dimensional (2-D) trigonometric and three-dimensional (3-D) elasticity solutions is considered. In the present 2-D solution, trigonometric terms are used for the displacements in addition to the initial terms of a power series through the thickness. The effects due to transverse shear and normal deformations are both included. The form of the assumed 2-D displacements is simplified by enforcing traction-free boundary conditions at the faces of the plate. No transverse shear correction factors are needed because a correct representation of the transverse Shearing Strain is given. The plate material is exponentially graded, meaning that Lame’s coefficients vary exponentially in a given fixed direction (the thickness direction). A wide variety of results for the displacements and stresses of an exponentially graded rectangular plate are presented. The validity of the present 2-D trigonometric solution is demonstrated by comparison with the 3-D elasticity solution. The influence of aspect ratio, side-to-thickness ratio and the exponentially graded parameter on the bending response are investigated.

  • generalized shear deformation theory for bending analysis of functionally graded plates
    Applied Mathematical Modelling, 2006
    Co-Authors: Ashraf M Zenkour
    Abstract:

    In this study, the static response is presented for a simply supported functionally graded rectangular plate subjected to a transverse uniform load. The generalized shear deformation theory obtained by the author in other recent papers is used. This theory is simplified by enforcing traction-free boundary conditions at the plate faces. No transversal shear correction factors are needed because a correct representation of the transversal Shearing Strain is given. Material properties of the plate are assumed to be graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The equilibrium equations of a functionally graded plate are given based on a generalized shear deformation plate theory. The numerical illustrations concern bending response of functionally graded rectangular plates with two constituent materials. The influences played by transversal shear deformation, plate aspect ratio, side-to-thickness ratio, and volume fraction distributions are studied. The results are verified with the known results in the literature.

J. Ezechiáš - One of the best experts on this subject based on the ideXlab platform.

  • Circular plates with Shearing Strain
    Computers & Structures, 2003
    Co-Authors: J. Ezechiáš
    Abstract:

    Abstract The Shearing Strain of plates is studied. The space position of the normal, which before deformation is perpendicular to the middle surface of plates can, after deformation, be fixed with the help of the rotations ψr(r, φ) and ψφ(r, φ) about the axes →er and →eφ. As a consequence of the free independent rotation of the normal vector, Shearing Strain arises. On the basis of this theory partial differential equations are derived which enable the three unknowns, ψr(r, φ), ψφ(r, φ) and ω(r, φ), to be determined. Two numerical examples are given for a plate with a rotary symmetrical loading: a free supported circular plate and a fixed plate. The results are dependent on the proportion h/R, where h is the thickness of the plate and R is the radius of the plate. When the theory is compared to Kirchhoff's classical theory of plates, it is seen that Kirchhoff's theory of plates does not admit Shearing Strain and as will be shown, it can be used only for calculations involving thin plates.

D Shangguan - One of the best experts on this subject based on the ideXlab platform.

  • deformation behavior of solder alloys under variable Strain rate Shearing creep conditions
    International Symposium on Advanced Packaging Materials. Processes Properties and Interfaces, 2005
    Co-Authors: Jin Liang, N Dariavach, D Shangguan
    Abstract:

    The rate-dependent deformation behavior of Sn3.8AgO.7Cu Pb-free alloy and Sn-Pb eutectic alloy under constant and variable Shearing Strain rates and creep conditions was studied systematically with thin-walled specimens using a biaxial servo-controlled tension-torsion material testing system. The Shearing tests were conducted at Strain rates between 10/sup -6//sec to 10/sup -1//sec. Variable Strain rate tests were also conducted for sudden Strain rates change and stress relaxation to study the post-yielding flow stress dependency on stress. Shearing creep tests were carried at room temperatures under a variety of stress level. It is believed that such a fundamental study of deformation behavior of solder alloys under complex stress conditions is important to understand effects of soldering processes and microstructures on solder interconnect reliability, and also to implement sophisticated 3D time-dependent nonlinear FEM analyses on electronic packages and assemblies.

  • deformation behavior of solder alloys under variable Strain rate Shearing creep conditions
    International Symposium on Advanced Packaging Materials. Processes Properties and Interfaces, 2005
    Co-Authors: Jin Liang, N Dariavach, D Shangguan
    Abstract:

    The rate-dependent deformation behavior of Sn3.8AgO.7Cu Pb-free alloy and Sn-Pb eutectic alloy under constant and variable Shearing Strain rates and creep conditions was studied systematically with thin-walled specimens using a biaxial servo-controlled tension-torsion material testing system. The Shearing tests were conducted at Strain rates between 10/sup -6//sec to 10/sup -1//sec. Variable Strain rate tests were also conducted for sudden Strain rates change and stress relaxation to study the post-yielding flow stress dependency on stress. Shearing creep tests were carried at room temperatures under a variety of stress level. It is believed that such a fundamental study of deformation behavior of solder alloys under complex stress conditions is important to understand effects of soldering processes and microstructures on solder interconnect reliability, and also to implement sophisticated 3D time-dependent nonlinear FEM analyses on electronic packages and assemblies.

Thomas S Hooyer - One of the best experts on this subject based on the ideXlab platform.

  • a ring shear device for the study of till deformation tests on tills with contrasting clay contents
    Quaternary Science Reviews, 1997
    Co-Authors: Neal R Iverson, Robert W Baker, Thomas S Hooyer
    Abstract:

    Abstract Deformation of subglacial sediment may have had a profound influence on the geomorphic effects and dynamics of Pleistocene ice sheets, but data that bear on the rheology of such sediment are few and contradictory. A means of studying systematically the mechanical properties of glacial tills is provided by a ring-shear device that shears a large annular specimen to high Strains at variable rates. Special features of the device allow continuous observation of the distribution of shear Strain, measurement of local stresses normal to the direction of shear, and isolation of wall effects. Thus far, a linear-viscous putty and two tills with different clay contents (4 and 32% by weight) have been tested. The experiments with till indicate, as expected, that the presence of dispersed clay minerals reduces markedly both the residual strength and hydraulic diffusivity of till. Clay also reduces spatial variations in normal stress associated with grain bridges. The walls bounding the specimen support only 9–17% of the total resistance to Shearing. Strain was localized in both tills, but not in the linear-viscous putty. Strain localization in the tills indicates that their theology departs significantly from linear- and Bingham-viscous models.

Nicola Luigi Rizzi - One of the best experts on this subject based on the ideXlab platform.

  • A beam model for the flexural–torsional buckling of thin-walled members with some applications
    Thin-walled Structures, 2008
    Co-Authors: Giuseppe Ruta, Marcello Pignataro, Valerio Varano, Nicola Luigi Rizzi
    Abstract:

    Abstract A beam model aimed at describing the flexural–torsional buckling of thin-walled members with non-symmetric cross-sections is presented. Two beam axes are introduced, and Strain is defined with respect to both. The Shearing Strain between the cross-section and one of the two axes is assumed to vanish; the warping is supposed to be linear in the twist. Non-linear hyperelastic constitutive relations are introduced; by means of standard localization and static perturbation techniques, the field equations describing the flexural–torsional buckling are obtained. One benchmark example is given and some numerical values of the critical load for various warping conStraints at the beam ends are provided.

  • A DIRECT ONE-DIMENSIONAL BEAM MODEL FOR THE FLEXURAL-TORSIONAL BUCKLING OF THIN-WALLED BEAMS
    Journal of Mechanics of Materials and Structures, 2006
    Co-Authors: Giuseppe Ruta, Marcello Pignataro, Nicola Luigi Rizzi
    Abstract:

    In this paper, the direct one-dimensional beam model introduced by one of the authors is refined to take into account nonsymmetrical beam cross-sections. Two different beam axes are considered, and the Strain is described with respect to both. Two inner conStraints are assumed: a vanishing Shearing Strain between the cross-section and one of the two axes, and a linear relationship between the warping and twisting of the cross-section. Considering a grade one mechanical theory and nonlinear hyperelastic constitutive relations, the balance of power, and standard localization and static perturbation procedures lead to field equations suitable to describe the flexural-torsional buckling. Some examples are given to determine the critical load for initially compressed beams and to evaluate their post-buckling behavior.