CISM Courses and Lectures: Resonant energy exchange in nonlinear oscillatory chains and Limiting Phase Trajectories: from small to large systems

Author(s):  
Leonid I. Manevitch ◽  
Valeri V. Smirnov
2010 ◽  
Vol 2010 ◽  
pp. 1-24 ◽  
Author(s):  
L. I. Manevitch ◽  
A. S. Kovaleva ◽  
E. L. Manevitch

We study a problem of energy exchange in a system of two coupled oscillators subject to 1 : 1 resonance. Our results exploit the concept of limiting phase trajectories (LPTs). The LPT, associated with full energy transfer, is, in certain sense, an alternative to nonlinear normal modes characterized by conservation of energy. We consider two benchmark examples. As a first example, we construct an LPT and examine the convergence to stationary oscillations for a Duffing oscillator subjected to resonance harmonic excitation. As a second example, we treat resonance oscillations in a system of two nonlinearly coupled oscillators. We demonstrate the reduction of the equations of motion to an equation of a single oscillator. It is shown that the most intense energy exchange and beating arise when motion of the equivalent oscillator is close to an LPT. Damped beating and the convergence to rest in a system with dissipation are demonstrated.


2011 ◽  
Vol 21 (10) ◽  
pp. 2919-2928
Author(s):  
E. L. MANEVITCH ◽  
L. I. MANEVITCH

The concept of limiting phase trajectories (LPT) has been introduced by one of the authors to describe intensive energy exchange between weakly coupled oscillators or oscillatory chains. It turns out that LPT can be considered as an alternative to nonlinear normal modes (NNMs), which are characterized by conservation of energy. LPT (in the introduced coordinates) describes the vibroimpact-type process with saw-tooth amplitude and a discontinuous derivative. It was shown earlier that this concept could also be extended to systems with one degree of freedom (DoF). In this case energy exchange between the oscillator and the source of energy can occur. In this paper, we generalize the above results in several ways, namely: (1) a consideration of the asymmetry of elastic potential; (2) a detailed description of the origin of vibroimpact-type behavior and the transition from nonresonant nonstationary oscillations to resonant ones (3) a direct application of obtained results to transient vibrations in strongly asymmetric 2DoF systems.


2003 ◽  
Vol 94 (6) ◽  
pp. 829-837 ◽  
Author(s):  
Ho Trung Dung ◽  
L. Knöll ◽  
D. -G. Welsch

1973 ◽  
Vol 22 (1) ◽  
pp. 144-145 ◽  
Author(s):  
C.J.S.M. Simpson ◽  
P.D. Gait ◽  
J.M. Simmie

1990 ◽  
Vol 55 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Wolfgang Linert

Many homologous series of reactions exhibit a common point of intersection in the ln k versus 1/T plots. This can be taken as a profound basis for the appearance of the isokinetic relationship (IKR) defining a temperature where rate (or equilibrium) constants of the series show a minimum in selectivity. The theoretically derived relationship describing the IKR and yielding a correlation between the isokinetic temperature and the frequencies available in an ideal heat bath is examined for real systems. It is shown that the role of the solvent in chemical reactions that exhibit isokinetic relationship is not only due to chemical interactions but also to energy transfer between reactants and solvents and vice versa.


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