Enhanced passive targeted energy transfer in strongly nonlinear mechanical oscillators

Single-degree-of-freedom (SDOF) nonlinear energy sinks (NESs) can efficiently mitigate broadband disturbances applied to primary linear systems by means of passive targeted energy transfer (TET), but for a rather limited range of energies. We demonstrate that the TET can be significantly enhanced for broad range of energies by introducing additional internal degrees of freedom to the NES in a highly asymmetric fashion. Numerical simulations demonstrate that the enhanced performance is due to a positive synergistic effect of the internal degrees of freedom of the proposed NES with highly asymmetric stiffnesses.     

Reflection of short rectangular pulses in the ideal string attached to strongly nonlinear oscillator

The system under consideration is ideal elastic string attached to strongly nonlinear oscillator with cubic nonlinearity by two different ways – immediately and by weak linear spring. The reflection of short rectangular pulses from the oscillator is accompanied by excitation of vibrations. The type of mode excited determines the amount of energy transferred to the oscillator as well as the structure of the reflected wave.     

Rapid non-resonant intermodal targeted energy transfer (IMTET) caused by vibro-impact nonlinearity

Nonlinear Dynamics - This paper describes a rapid and efficient nonlinear non-resonance mechanism for low-to-high-frequency energy scattering, which is referred to as intermodal targeted energy...     

Escape of a forced-damped particle from weakly nonlinear truncated potential well

Nonlinear Dynamics - Escape from a potential well is an extreme example of transient behavior. We consider the escape of the harmonically forced particle under viscous damping from the benchmark...     

A monopole mass filter with a hyperbolic V-shaped electrode

In this article we compare the classical monopole mass filter of von Zahn and the monopole mass filter with a hyperbolic V-shaped electrode. The experimental results and those of computer simulation for both mass spectrometers are presented. We show that the replacement of a conventional 90 degrees V-shaped electrode by an electrode with a hyperbolic profile substantially improves the peak shape of any given mass, and increases the mass resolution by a factor of 3-4 and the abundance sensitivity by a factor of 100. The potential of high analytical performance combined with electroforming techniques for electrode manufacture indicate future practical uses of such instruments. Copyright 1999 John Wiley & Sons, Ltd.     

Interaction of elastic system with snap-through vibration absorber

Interaction of essentially non-linear vibration absorber (snap-through truss) with primary 1DOF linear oscillator is investigated. The study covers both free and forced (external excitation applied to the linear oscillator) responses of the system. The analysis is performed by complexification-averaging technique, describing a slow variation of amplitudes of principal harmonic components. Periodic and quasiperiodic oscillations are revealed and investigated. It turns out that for realistic parameters of the system vast majority of the responses, including those suitable for the vibration absorption, is quasiperiodic. The results are verified by means of a direct numeric simulation.     

Mesoscopic patterning in evaporated polymer solutions: new experimental data and physical mechanisms

Mesoscopically ordered patterns were obtained when polymer solutions were applied to tilted substrates and evaporated immediately under ambient conditions in a slow air current. The patterns were studied with optical, scanning electron, and atomic force microscopy. Shadowgraph visualization of the patterning was carried out, and visualization of the flow with an ink tracer was performed. Restrained and nonrestrained flows of the polymer solution gave rise to very similar patterning. The formation of the patterns on different solid substrates, including substrates wetted with silicon oil, was investigated. The concentration of the polymer solutions exerted an influence on the characteristic dimension of mesoscaled cells. A physical mechanism of the patterning is proposed. The mechanism is based on the mass transport instability occurring under the intensive evaporation of the solvent. The model satisfactorily explains the experimental findings.     

On the escape of a resonantly excited couple of particles from a potential well

Nonlinear Dynamics - The escape dynamics of a damped system of two coupled particles in a truncated potential well under biharmonic excitation are investigated. It is assumed that excitation...