Yi-Ze Wang

Effects of Axial Load and Elastic Matrix on Flexural Wave Propagation in Nanotube With Nonlocal Timoshenko Beam Model

In this paper, the effects of the axial load and the elastic matrix on the flexural wave in the carbon nanotube are studied. Based on the nonlocal continuum theory and the Timoshenko beam model, the equation of the flexural wave motion is derived. The dispersion relation between the frequency and the wave number is illustrated. The characteristics of the flexural wave propagation in the carbon nanotube embedded in the elastic matrix with the axial load are analyzed. The wave frequency and the phase velocity are presented with different wave numbers. Furthermore, the small scale effects on the wave properties are discussed.

Homoclinic behaviors and chaotic motions of double layered viscoelastic nanoplates based on nonlocal theory and extended Melnikov method

The nonlinear dynamical equations are established for the double layered viscoelastic nanoplates (DLNP) subjected to in-plane excitation based on the nonlocal theory and von Kármán large deformation theory. The extended high dimensional homoclinic Melnikov method is employed to study the homoclinic phenomena and chaotic motions for the parametrically excited DLNP system. The criteria for the homoclinic transverse intersection for both the asynchronous and synchronous buckling cases are proposed. Lyapunov exponents and phase portraits are obtained to verify the Melnikov-type analysis. The influences of structural parameters on the transverse homoclinic orbits and homoclinic bifurcation sets are discussed for the two buckling cases. Some novel phenomena are observed in the investigation. It should be noticed that the nonlocal effect on the homoclinic behaviors and chaotic motions is quite remarkable. Hence, the small scale effect should be taken into account for homoclinic and chaotic analysis for nanostructures. It is significant that the nonlocal effect on the homoclinic phenomena for the asynchronous buckling case is quite different from that for the synchronous buckling case. Moreover, due to the van der Walls interaction between the layers, the nonlocal effect on the homoclinic behaviors and chaotic motions for high order mode is rather tiny under the asynchronous buckling condition.

Active feedback control of elastic wave metamaterials

As an important extension of periodic structures and phononic crystals, elastic wave/acoustic metamaterials can show negative effective parameters for special frequency regions. Although the active control method is widely applied to the vibration isolation and elastic wave propagation, little attention has been paid on changing elastic wave/acoustic properties of metamaterials. In this work, a new kind of elastic wave metamaterials combined with the automatic control system is presented. Propagation behaviors of the elastic wave are discussed. To demonstrate the effect of the active feedback control, the stop band properties, tunable negative effective mass and control system stability are considered. The results show that the negative acceleration feedback control can enhance the frequency region that creates the negative effective mass. Moreover, the stability of this periodic structure can be achieved.

Band Gap Properties of Piezoelectric/Viscous Liquid Phononic Crystals

The viscous effects on the band gap characteristics of the piezoelectric/viscous liquid phononic crystals are studied. The expressions of the generalized eigenvalue equation for the cylindrical phononic crystals are derived. Numerical calculations are performed to discuss the band gap characteristics with different filling ratios and viscous damping parameters. Form the results, it can be observed that the out-of-plane mode will appear, which caused by the viscous effects. Both of the real and imaginary parts of frequencies will increase with the filling fraction becoming larger. The maximum of the normalized band gap width is achieved by f = 0.5. Furthermore, the band gap edges become higher with the viscous damping parameter increasing, especially for higher band gaps.Copyright