The vibration characteristics of piezoelectric hollow-disc transducers were investigated in this paper. It was assumed that the vibration modes were coupled in the axial and radial directions. Theoretically the differential equations of piezoelectric motions were derived in terms of the axial and radial displacements and the electric potential. Solutions of the boundary value problem yielded th...

In this paper, the nonlinear vibration analysis of a thin cylindrical shell made of Functionally Graded Material (FGM) resting on a nonlinear viscoelastic foundation under compressive axial and lateral loads is studied. Nonlinear governing coupled partial differential equations of motions (PDEs) for cylindrical shell are derived using improved Donnell shell theory. The equations of motions (EOM...

This paper investigates the coupled axial-radial (CAR) vibration of single-walled carbon nanotubes (SWCNTs) based on doublet mechanics (DM) with a scale parameter. Two coupled forth order partial differential equations that govern the CAR vibration of SWCNTs are derived. It is the first time that DM is used to model the CAR vibration of SWCNTs. To obtain the natural frequency and dynamic respon...

In this study, the vibration behavior of functional graded (FG) circular and annular nanoplate embedded in Visco-Pasternak foundation and coupled with temperature change is studied. It is assumed that a uniform radial magnetic field acts on the top surface of the plate and the magnetic permeability coefficient of the plate along its thickness are assumed to vary according to the volume distribu...

This paper presents a novel method to nonlinearly investigate the dynamics of the coupled axial and torsional vibrations in the circular cross section beam of the steam turbine generator using the FFT analysis. Firstly, the coupled axial and torsional vibrations of a beam are proved by equivalent law of shearing stress and different boundary conditions. Then, a nonlinear mathematical model of t...

For an induction machine, we suggest a theoretical development of the mechanical unbalance effect on the analytical expressions of radial vibration and stator current. Related spectra are described and characteristic defect frequencies are determined. Moreover, the stray flux expressions are developed for both axial and radial sensor coil positions and a substitute diagnosis technique is propos...

Turbomachinery shafting and casings typically experience axial growth during thermal transients occurring at startup, shutdown, and changes of load. This growth does not usually present difficulties during operation. However, this paper discusses four recent turbomachinery trains that experienced radial subsynchronous vibration resulting from axial misalignment. In each example, the train inclu...

Interest in vibration control in systems employing rolling element bearings, ranging from rotor systems used in energy conversion/transmission to high-precision, multi-degree-offreedom optical positioning systems, has focused attention on the modelling of bearing dynamic stiffness properties. While modelling a rolling element bearing either as an ideal boundary condition for a shaft or as a sim...

Wave vibration analysis approach is found a systematic and concise approach in solving complex vibration problems in built-up frame structures. From the wave vibration standpoint, vibrations propagate along a uniform waveguide, and are reflected and transmitted at discontinuities. In this study, a multi-story multi-bay steel frame is built. The wave vibration analysis approach is applied to stu...

The effects of vibration parameters, operating conditions and material properties on bed voidage were investigated using an optical fiber probe approach in a vibrating fluidized bed with a diameter of 148 mm. Variables studied included frequency (0-282 s), amplitude (0 mm-1 mm), bed height (0.1 m-0.4 m) as well as four kinds of particles (belonging to Geldart's B and D groups). The axial and ra...