A new concept for obtaining large-amplitude rotary displacements from small linear displacements generated by induced-strain active material stacks is considered. The concept utilizes the theory of twist-warping coupling in thin-wall open tubes. A large-displacement induced-strain rotary actuator, LARIS Mk 2, was built and tested under static and dynamic conditions. A rotary displacement of 6 w...

The interaction between friction and vibration is a widely recognised source of inefciency in all mechanical systems. The nature of this interaction is very dependent on the dynamic environment and its control requires a detailed understanding of the mathematical structure governing the stability of this environment. Although the fundamental causes of friction-induced intermittent motion have b...

For remote offshore wind farms, transmitting power to the main onshore grid via a Voltage Source Converter High Direct Current (VSC-HVDC) system is mainstream of transmission. It not only cost-effective in long-distance transmission, but also can fully meet side requirements such as black start, voltage support, fault ride through and frequency support. However, it still has some problems, poss...

We present the small-amplitude vibrations of a circular elastic ring with periodic and clamped boundary conditions. We model the rod as an inextensible, isotropic, naturally straight Kirchhoff elastic rod and obtain the vibrational modes of the ring analytically for periodic boundary conditions and numerically for clamped boundary conditions. Of particular interest are the dependence of the vib...

Laser-induced fluorescence, resonant two-photon ionization, UV-UV hole burning, UV depletion, and single vibronic level fluorescence (SVLF) spectra of jet-cooled diphenylmethane (DPM) have been recorded over the 37 300-38 400 cm(-1) region that encompasses the S(1)<--S(0) and S(2)<--S(0) transitions. All transitions in the laser-induced fluorescence excitation spectrum are due to a single confo...

We report an analysis of the archival Rossi X-ray Timing Explorer (RXTE) data from the December 2004 hyperflare from SGR 1806-20. In addition to the ≈ 90 Hz QPO first discovered by Israel et al., we report the detection of higher frequency oscillations at ≈ 150, 625, and 1,840 Hz. In addition, we also find indications of oscillations at ≈ 720, and 2,384 Hz, but with lower significances. The 150...

In recent years wind energy has been the world’s fastest growing source of energy. The wind turbine industry is booming and is spending a lot on research for improving the performance of its present machines and increasing their capacity. However, upscaling of the classical drivetrain concept is no longer economically feasible for machine power of 2 MW and higher. This paper presents the prelim...

Vibrations of the Jeffcott rotor are modelled by a three degree of freedom system including coupling between lateral and torsional modes. The crack in a rotating shaft of the rotor is introduced via time dependent stiffness with off diagonal couplings. Applying the external torque to the system allows to observe the effect of crack ”breathing” and gain insight into the system. It is manifested ...