The oil and gas industry has a growing demand for electrically driven trains operated at variable speeds. Variable frequency electrical drives enable increased operational flexibility and energy efficiency. This is of great importance in applications requiring high power, such as gas compression. Load commutated inverters (LCIs) are one of the most widespread technologies for driving large gas ...

Wet friction clutches play a critical role in vehicles equipped with automatic transmissions. It is unavoidable that they progressively degrade and eventually break down while the vehicles are under operational condition. To avoid unexpected failures, a proper condition monitoring tool extended with a lifetime prediction method should be implemented. In order to achieve this, appropriate parame...

In this paper the effect of quadratic and cubic non-linearities of the system consisting of the crankshaft and torsional vibration damper (TVD) is taken into account. TVD consists of non-linear elastomer material used for controlling the torsional vibration of crankshaft. The method of multiple scales is used to solve the governing equations of the system. Meanwhile, the frequency response of t...

We report the first direct observation of the hydrogen-bond stretching vibration for a water cluster. A perpendicular band of ~D2O!3 was measured by terahertz laser vibration–rotation–tunneling spectroscopy at 142.8 cm in the ‘‘translational band’’ region of the liquid corresponding to the hindered translational motions of water molecules. We have tentatively assigned the spectrum to transition...

This paper analyzes the reason of Low-speed vibration in an electric vehicle, builds the mathematical equation of powertrain torsional vibration. Then, the model of torque ripple considering non-sinusoidal magnetic field distribution is built, orders and frequencies of torque ripple in PMSM is predicted. According to the relationship between the torsional vibration in low-speed of the electric ...

Elastic waves exhibit rich polarization characteristics absent in acoustic and electromagnetic waves. By designing a solid elastic metamaterial based on three-dimensional anisotropic locally resonant units, here we experimentally demonstrate polarization bandgaps together with exotic properties such as 'fluid-like' elasticity. We construct elastic rods with unusual vibrational properties, which...

Torsional dynamic analysis of carbon nanotubes under the effect of longitudinal magnetic field is carried out in the present study. Torque effect of an axial magnetic field on a carbon nanotube has been defined using Maxwell’s relation. Nonlocal governing equation and boundary conditions for carbon nanotubes are obtained by using Hamilton’s minimum energy principle. Eringen’s nonlocal stress gr...

A B S T R A C T Pump shafts used for power generation are susceptible to fatigue cracking while often in near-continuous operation. Technology based on torsional vibration is under development for condition-based assessment of shaft health. The focus of this paper is on the relationship between a crack, which propagated due to bending loads, and the torsional stiffness of the shaft. An analytic...

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...