The Experts below are selected from a list of 24987 Experts worldwide ranked by ideXlab platform

Shuzhu Zhang - One of the best experts on this subject based on the ideXlab platform.

  • nonlocal nonlinear model of bernoulli euler nanobeam with small Initial Curvature and its application to single walled carbon nanotubes
    Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems, 2019
    Co-Authors: Kun Huang, Shuzhu Zhang
    Abstract:

    Although the small-scale effect and Initial Curvature have significant influence on the nonlinear mechanical property of the nanobeam, there are few researches to consider both factors. On the basis of the nonlocal differential constitutive relation, this paper, for the first time, presents a nonlinear partial differential–integral equation model of Bernoulli–Euler nanobeam with a small Initial Curvature. Then the model is applied to research the static bending and the frequency of free vibration for the single-walled carbon nanotubes (SWCNTs). This study indicates that the static deformations are relate to the load direction due to the Initial Curvature. In addition, the Initial Curvature complicates the relation between the free vibration frequencies and vibration amplitudes.

  • Nonlocal nonlinear model of Bernoulli–Euler nanobeam with small Initial Curvature and its application to single-walled carbon nanotubes
    Microsystem Technologies, 2019
    Co-Authors: Kun Huang, Shuzhu Zhang
    Abstract:

    Although the small-scale effect and Initial Curvature have significant influence on the nonlinear mechanical property of the nanobeam, there are few researches to consider both factors. On the basis of the nonlocal differential constitutive relation, this paper, for the first time, presents a nonlinear partial differential–integral equation model of Bernoulli–Euler nanobeam with a small Initial Curvature. Then the model is applied to research the static bending and the frequency of free vibration for the single-walled carbon nanotubes (SWCNTs). This study indicates that the static deformations are relate to the load direction due to the Initial Curvature. In addition, the Initial Curvature complicates the relation between the free vibration frequencies and vibration amplitudes.

R.j. Pomeroy - One of the best experts on this subject based on the ideXlab platform.

  • Axial Curvature and residual stress measurement in thin-walled tubes
    International Journal of Mechanical Sciences, 2003
    Co-Authors: R.j. Pomeroy
    Abstract:

    Abstract The effect of Initial Curvature in a previously derived expression relating bending moment to beam Curvature is discussed. It it proposed that if Initial Curvature is large compared with elastic orders of Curvature some simplification is possible. A method used elsewhere to examine anticlastic bending is extended to provide an analysis of axial bending in thin-walled tubes. The resulting solution is applied to previous experimental data measuring the residual stresses in thin-walled cylindrical tube and good agreement is observed.

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

  • Dynamic failure of double deck spherical reticulated shell with imperfections
    2011 Second International Conference on Mechanic Automation and Control Engineering, 2011
    Co-Authors: Dong Chen, Xiu-xing Wang
    Abstract:

    The double deck spherical reticulated shell is the structure which is sensitive to imperfections. The Initial imperfections influencing structural dynamic failure are Initial Curvature and residual stress of bar element and installation deviation of nodes. With the ANSYS secondary exploitation, the programs of bar element were written to consider the influences of Initial Curvature and residual stress. Based on these works, the influences of the three imperfections on dynamic failure of the spherical reticulated shell were got by IDA.

  • Dynamic failure of single-layer spherical reticulated shell with imperfections
    2011 Second International Conference on Mechanic Automation and Control Engineering, 2011
    Co-Authors: Dong Chen, Xiu-xing Wang
    Abstract:

    The single-layer spherical reticulated shell is the structure which is sensitive to imperfections. The Initial imperfections reducing structural stability included Initial Curvature and residual stress of element and installation deviation of nodes. The stress-strain curve concerning the residual stress was got by model CRC, the influence of Initial Curvature was got by the half-sinusoid and the programs about them were programmed by ANSYS secondary exploitation. Based on these works, the influences of the three imperfections on dynamic failure of the spherical reticulated shell were got by IDA.

Peter Gudmundson - One of the best experts on this subject based on the ideXlab platform.

  • Thermal Deformation of Initially Curved Substrates Coated by Thin Inhomogeneous Layers
    Journal of Applied Mechanics, 2000
    Co-Authors: Adam Wikström, Peter Gudmundson
    Abstract:

    Thermal Curvature changes and membrane strains are analyzed for elastic shallow shell substrates which are coated by thin, generally inelastic, inhomogeneous and anisotropic layers. The analysis is restricted to linear kinematics. It is shown that the deformation is governed by the corresponding solution for a flat substrate and a correction due to the Initial Curvature. The correction is determined from a shallow shell problem for the bare substrate with a loading expressed by the coefficients of thermal Curvature for the substrate/layer system. For constant Initial Curvature, certain analytic solutions are presented. For situations when the Initial deflection of the substrate is much larger than the substrate thickness, a boundary layer solution is derived. In the particular case of a circular isotropic substrate with a spherical Initial Curvature and a coating of arbitrary anisotropy, the solution is presented in closed form. For nonflat substrates, measured Curvatures can generally not be used to extract layer stresses without a proper compensation for the Initial Curvature. In this paper, it is explicitly presented how to accurately compensate for a spherical Initial Curvature. The results are particularly discussed in relation to Curvature measurements on Silicon substrates.

  • Stresses in Thin Coatings from Curvature Measurements on Non-Planar Substrates
    MRS Proceedings, 2000
    Co-Authors: Adam Wikström, Peter Gudmundson
    Abstract:

    AbstractMechanical elastic and inelastic properties of thin coatings are often studied by means of the Curvature measurement technique in combination with the Stoney formula. It is then implicitly assumed that the elastic substrate is Initially flat which implies that the Curvatures theoretically remain constant over the substrate. If the substrate has a slight Initial Curvature, a different situation arises. In this case, the Curvatures will vary over the substrate. It has recently been shown that in spite of this, the stresses that appear in the thin coating will remain constant over the surface of the substrate. Therefore, measured Curvatures can generally not be used to extract layer stresses without a proper compensation for the Initial Curvature. A general method for the extraction of mechanical properties from Curvature measurements on non-planar substrates is outlined. The method is valid for linear as well as non-linear shell theories. The compensation needed to evaluate a coating on a circular substrate with spherical Initial Curvature is studied for all relevant parameters. The results are particularly discussed in relation to Curvature measurements on silicon wafers.

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

  • Stability analysis of an embedded single-walled carbon nanotube with small Initial Curvature based on nonlocal theory
    Mechanics of Advanced Materials and Structures, 2016
    Co-Authors: A. Arefi, H. Nahvi
    Abstract:

    ABSTRACTMany experimental observations have shown that most nanostructures, such as carbon nanotubes, are often characterized by a certain degree of waviness along their axial direction. This geometrical imperfection has profound effects on the mechanical behavior of carbon nanotubes. In the present work, stability of a slightly curved carbon nanotube under lateral loading is investigated based on Eringen's nonlocal elasticity theory. Euler Bernoulli and Timoshenko beam theories are employed to obtain equilibrium equations. Winkler-Pasternak elastic foundation is used to approximate the effect of matrix. Effects of Initial Curvature, nonlocal parameter, beam length, and elastic foundation parameters on initiation of critical conditions are investigated.

  • Investigations on Vibration and Buckling of Carbon Nanotubes with Small Initial Curvature by Nonlocal Elasticity Theory
    Fullerenes Nanotubes and Carbon Nanostructures, 2014
    Co-Authors: A. Arefi, M. Salimi
    Abstract:

    Many experimental observations have shown that in most nanostructures such as nanocomposites, carbon nanotubes (CNTs) are often characterized by a certain degree of waviness along their axial dimension. This geometrical imperfection has a profound effect on the mechanical behavior of CNTs. In the present work, the effects of Initial Curvature, shear deformation and influence of surrounding medium that are modeled as Winkler-Pasternak elastic foundation on behavior of slightly curved carbon nanotubes are investigated. It is shown that the Initial Curvature has an important role on mechanical behavior of curved carbon nanotubes. To capture the small size effects, nonlocal elasticity theory is implemented. Timoshenko beam theory (TBT) is used to model the behavior of CNTs and the governing equations are solved analytically. The effects of Initial height and shear deformation on vibration frequencies and buckling loads are studied. It is found that these effects considerably contribute to mechanical behavior ...