Numerical studies on passive suppression of one and two degrees-of-freedom vortex-induced vibrations using a rotative non-linear vibration absorber

2019 ◽  
Vol 116 ◽  
pp. 230-249 ◽  
Author(s):  
Tatiana Ueno ◽  
Guilherme Rosa Franzini
Keyword(s):  
Degrees Of Freedom ◽  
Vibration Absorber ◽  
Linear Vibration ◽  
Two Degrees Of Freedom ◽  
Numerical Studies ◽  
Vortex Induced Vibrations ◽  
Non Linear

Vortex-Induced Vibrations of a Rigid Cylinder on Non-Linear Elastic Supports

2006 ◽  
Author(s):  
S. Bourdier ◽  
J. R. Chaplin
Keyword(s):  
Circular Cylinder ◽  
Phase Flow ◽  
Linear Vibration ◽  
Chaotic Motions ◽  
Frequency Spectra ◽  
Elastic Supports ◽  
Linear Elastic ◽  
Vortex Induced Vibrations ◽  
Non Linear ◽  
Insight Into

The dynamics of vortex-induced vibrations of a rigid circular cylinder with structural non-linearities, introduced by means of discontinuities in the support system, are studied experimentally. The analysis of the measurements is carried out using non-linear vibration tools, i.e phase-flow portraits, frequency spectra, Lyapunov exponents and correlation dimensions, to provide an insight into the dynamical changes in the system brought about by restricting the motion. We show that chaotic motions can occur due to the structural non-linearities.

Effects of Suspension Design on the Attitudes of a Car during Braking and Acceleration

1973 ◽  
Vol 187 (1) ◽  
pp. 787-794
Author(s):  
J. R. Ellis
Keyword(s):  
Steady State ◽  
Linear Systems ◽  
Degrees Of Freedom ◽  
Coupled Systems ◽  
Two Degrees Of Freedom ◽  
Simulation Techniques ◽  
Non Linear ◽  
Non Linear Systems ◽  
Effort Distribution

Two degrees of freedom models of a car are employed to demonstrate the effects of the suspension derivative ∂ x/∂ z on the pitch and bounce attitudes during braking or accelerating. The work equation is employed to show that brake effort distribution between the axles has a significant effect on the attitudes when anti-dive suspension characteristics are utilized. The steady-state positions in both pitch and bounce are developed for linear systems of typical suspensions that may be either standard or coupled systems. Non-linear systems are considered using simulation techniques. A description of some simulation circuits is contained in an appendix.

NON-LINEAR GENERALIZATION OF THE GAUGE AMBIGUITIES OF THE LAGRANGIAN FORMALISM

1991 ◽  
Vol 06 (05) ◽  
pp. 737-748 ◽  
Author(s):  
JOSÉ F. CARIÑENA ◽  
MANUEL F. RAÑADA
Keyword(s):  
Degrees Of Freedom ◽  
Lagrangian Formalism ◽  
Two Degrees Of Freedom ◽  
Gauge Equivalence ◽  
General Properties ◽  
Non Linear

A generalization of the gauge equivalence of Lagrangians is developed. In this approach the different Lagrangians determine not only the same set of solutions but also the same energies. Some general properties are studied and then the case of velocity-free forces is considered. In particular we show the non-existence for n=2 (two degrees of freedom) of such equivalent Lagrangians and that when n=3 the only forces admitting such equivalent Lagrangians correspond to those deriving from central potentials.

scholarly journals Vibro-impact attachments as shock absorbers

2008 ◽  
Vol 222 (10) ◽  
pp. 1899-1908 ◽  
Author(s):  
I Karayannis ◽  
A F Vakakis ◽  
F Georgiades
Keyword(s):  
Energy Dissipation ◽  
Vibration Absorber ◽  
Linear Vibration ◽  
Shock Energy ◽  
Shock Absorbers ◽  
Non Linear ◽  
Parametric Studies ◽  
Primary Structures ◽  
Shock Protection

The use of vibro-impact (VI) attachments as shock absorbers is studied. By considering different configurations of primary linear oscillators with VI attachments, the capacity of these attachments to passively absorb and dissipate significant portions of shock energy applied to the primary systems is investigated. Parametric studies are performed to determine the dependence of energy dissipation by the VI attachment in terms of its parameters. Moreover, non-linear shock spectra are used to demonstrate that appropriately designed VI attachments can significantly reduce the maximum levels of vibration of primary systems over wide frequency ranges. This is in contrast to the classical linear vibration absorber, whose action is narrowband. In addition, it is shown that VI attachments can significantly reduce or even completely eliminate resonances appearing in the linear shock spectra, thus providing strong, robust, and broadband shock protection to the primary structures to which they are attached.

NON-LINEAR VIBRATION ABSORBER FOR A SYSTEM UNDER SINUSOIDAL AND RANDOM EXCITATION: EXPERIMENTS

2002 ◽  
Vol 249 (4) ◽  
pp. 701-718 ◽  
Author(s):  
O. CUVALCI ◽  
A. ERTAS ◽  
S. EKWARO-OSIRE ◽  
I. CICEK
Keyword(s):  
Random Excitation ◽  
Vibration Absorber ◽  
Linear Vibration ◽  
Non Linear

The Numerical Research of Two-Degrees-of-Freedom Vortex-Induced Vibrations of Circular Cylinders

2012 ◽  
Vol 204-208 ◽  
pp. 4598-4601
Author(s):  
Jie Li Fan ◽  
Wei Ping Huang
Keyword(s):  
Degrees Of Freedom ◽  
Amplitude Ratio ◽  
Flow Direction ◽  
Cross Flow ◽  
Circular Cylinders ◽  
Two Degrees Of Freedom ◽  
Line Frequency ◽  
Ansys Cfx ◽  
Vortex Induced Vibrations ◽  
Lock In

The two-degrees-of-freedom of vortex-induced vibration of circular cylinders is numerically simulated with the software ANSYS/CFX. The VIV characteristic, in the two different conditions (A/D=0.07 and A/D=1.0), is analyzed. When A/D is around 0.07, the amplitude ratio of the cylinder’s VIV between in-line and cross-flow direction in the lock-in is lower than that in the lock-out. The in-line frequency is twice of that in cross-flow direction in the lock-out, but in the lock-in, it is the same as that in cross-flow direction and the same as that of lift force. When A/D is around 1.0, the amplitude ratio of the VIV between in-line and cross-flow in the lock-in is obviously larger than that in the lock-out. Both in the lock-in and in the lock-out, the in-line frequency is twice of that in cross-flow direction.

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