Timon Rabczuk | Bauhaus-University-Weimar - Academia.edu (original) (raw)
Papers by Timon Rabczuk
We study the phonon modes in single-walled MoS$_{2}$ nanotubes via the lattice dynamics calculati... more We study the phonon modes in single-walled MoS$_{2}$ nanotubes via the lattice dynamics calculation and molecular dynamics simulation. The phonon spectra for tubes of arbitrary chiralities are calculated from the dynamical matrix constructed by the combination of an empirical potential with the conserved helical quantum numbers (kappa,n)(\kappa, n)(kappa,n). In particular, we show that the frequency ($\omega$) of the radial breathing mode is inversely proportional to the tube diameter ($d$) as omega=665.3/d\omega=665.3/domega=665.3/d {cm$^{-1}$}. The eigen vectors of the first twenty lowest-frequency phonon modes are illustrated. Based on these eigen vectors, we demonstrate that the radial breathing oscillation is disturbed by phonon modes of three-fold symmetry initially, and the tube is squashed by the modes of two-fold symmetry eventually. Our study provides fundamental knowledge for further investigations of the thermal and mechanical properties of the MoS$_{2}$ nanotubes.
In this paper, non-uniform rational B-spline based iso-geometric finite element method is used to... more In this paper, non-uniform rational B-spline based iso-geometric finite element method is used to study the static and dynamic characteristics of functionally graded material (FGM) plates. The material properties are assumed to be graded only in the thickness direction and the effective properties are computed either using rule of mixtures or by Mori-Tanaka homogenization scheme. The plate kinematics is based on first order shear deformation plate theory. Two new techniques are proposed to avoid shear locking when the present formulation is applied to thin plates. The shear correction factors are evaluated employing the energy equivalence principle. Static bending, mechanical and thermal buckling, linear free flexural vibration and supersonic flutter analysis of FGM plates are numerically studied. The accuracy of the present formulation is validated against available three-dimensional solutions. A detailed numerical study is carried out to examine the influence of the gradient index, the plate aspect ratio and the plate thickness on the global response of functionally graded material plates.
Composite Structures, 2015
ABSTRACT
Latin American Journal of Solids and Structures
Journal of Computational and Applied Mathematics
Computers and Geotechnics, 2015
We study the phonon modes in single-walled MoS$_{2}$ nanotubes via the lattice dynamics calculati... more We study the phonon modes in single-walled MoS$_{2}$ nanotubes via the lattice dynamics calculation and molecular dynamics simulation. The phonon spectra for tubes of arbitrary chiralities are calculated from the dynamical matrix constructed by the combination of an empirical potential with the conserved helical quantum numbers (kappa,n)(\kappa, n)(kappa,n). In particular, we show that the frequency ($\omega$) of the radial breathing mode is inversely proportional to the tube diameter ($d$) as omega=665.3/d\omega=665.3/domega=665.3/d {cm$^{-1}$}. The eigen vectors of the first twenty lowest-frequency phonon modes are illustrated. Based on these eigen vectors, we demonstrate that the radial breathing oscillation is disturbed by phonon modes of three-fold symmetry initially, and the tube is squashed by the modes of two-fold symmetry eventually. Our study provides fundamental knowledge for further investigations of the thermal and mechanical properties of the MoS$_{2}$ nanotubes.
In this paper, non-uniform rational B-spline based iso-geometric finite element method is used to... more In this paper, non-uniform rational B-spline based iso-geometric finite element method is used to study the static and dynamic characteristics of functionally graded material (FGM) plates. The material properties are assumed to be graded only in the thickness direction and the effective properties are computed either using rule of mixtures or by Mori-Tanaka homogenization scheme. The plate kinematics is based on first order shear deformation plate theory. Two new techniques are proposed to avoid shear locking when the present formulation is applied to thin plates. The shear correction factors are evaluated employing the energy equivalence principle. Static bending, mechanical and thermal buckling, linear free flexural vibration and supersonic flutter analysis of FGM plates are numerically studied. The accuracy of the present formulation is validated against available three-dimensional solutions. A detailed numerical study is carried out to examine the influence of the gradient index, the plate aspect ratio and the plate thickness on the global response of functionally graded material plates.
Composite Structures, 2015
ABSTRACT
Latin American Journal of Solids and Structures
Journal of Computational and Applied Mathematics
Computers and Geotechnics, 2015