Comments on a nonlinear and nonideal electromechanical damping vibration absorber, Sommerfeld effect and energy transfer

2008 ◽  
Vol 55 (1-2) ◽  
pp. 1-11 ◽  
Author(s):  
Jorge Luis Palacios Felix ◽  
José M. Balthazar
Keyword(s):  
Energy Transfer ◽  
Vibration Absorber ◽  
Sommerfeld Effect

On the Parametric Excitation of Pendulum-Type Vibration Absorber

1961 ◽  
Vol 28 (3) ◽  
pp. 330-334 ◽  
Author(s):  
Eugene Sevin
Keyword(s):  
Energy Transfer ◽  
Numerical Solution ◽  
Parametric Excitation ◽  
Equations Of Motion ◽  
Vibration Absorber ◽  
Single Cycle ◽  
Linearized System ◽  
Nonlinear Equations Of Motion ◽  
Beam Oscillation ◽  
Energy Interchange

The free motion of an undamped pendulum-type vibration absorber is studied on the basis of approximate nonlinear equations of motion. It is shown that this type of mechanical system exhibits the phenomenon of auto parametric excitation; a type of “instability” which cannot be accounted for on the basis of the linearized system. Complete energy transfer between modes is shown to occur when the beam frequency is twice the simple pendulum frequency. On the basis of a numerical solution, approximately 150 cycles of the beam oscillation take place during a single cycle of energy interchange.

Pendulum as Vibration Absorber for Flexible Structures: Experiments and Theory

1996 ◽  
Vol 118 (4) ◽  
pp. 558-566 ◽  
Author(s):  
O. Cuvalci ◽  
A. Ertas
Keyword(s):  
Energy Transfer ◽  
Coupling Effect ◽  
Equations Of Motion ◽  
Flexible Structures ◽  
Experimental Results ◽  
Vibration Absorber ◽  
Pendulum System ◽  
Nonlinear Equations Of Motion ◽  
Tip Mass ◽  
Sinusoidal Excitation

The dynamic response of a beam-tip mass-pendulum system subjected to a sinusoidal excitation is investigated. A simple pendulum mounted to a tip mass of a beam is used as a vibration absorber. The nonlinear equations of motion are developed to investigate the autoparametric interaction between the first two modes of the system. The nonlinear terms appear due to the curvature of the beam and the coupling effect between the beam and pendulum. Complete energy transfer between modes is shown to occur when the beam frequency is twice the pendulum frequency. Experimental results are compared with a theoretical solution obtained using numerical integration. The experimental results are in qualitative agreement with the theory.

Sommerfeld Effect and Passive Energy Reallocation in a Self-Synchronizing System

2018 ◽  
Author(s):  
Anubhab Sinha ◽  
Saurabh Kumar Bharti ◽  
Arun Kumar Samantaray ◽  
Ranjan Bhattacharyya
Keyword(s):  
Nonlinear Energy Sink ◽  
Power Input ◽  
Vibration Absorber ◽  
Sommerfeld Effect ◽  
Structural Vibrations ◽  
Dynamic Vibration Absorber ◽  
Jump Phenomena ◽  
Energy Sink ◽  
Nonlinear Energy ◽  
Base Structure

Two eccentric rotors are mounted rigidly on a common vibrating base structure. Each of these rotors are separately driven by two motors, which are by nature non-ideal. Although power input for both rotors are different, the two rotors acquire the same speed via communication through the energized vibrating base. The phenomena is known as ‘self-synchronization’. Additionally, the presence of two non-ideal drives within the vibrating system also lead to the onset of the nonlinear jump phenomena (formally known as the Sommerfeld effect). Numerical simulations are carried out on a model developed on MSC Adams. From the generated responses, an overview of ‘self-synchronization’ as well as the various modes of synchronization are studied adjacent to the nature of Sommerfeld effect inherent within this system. The aim is to reduce the structural vibrations, mainly by virtue of self-synchronization. Henceforth, the behavior of the synchronized system is also examined in the presence of two secondary vibration reducing devices — a tuned Dynamic Vibration Absorber (DVA) and a Nonlinear Energy Sink (NES). Both are designed to passively absorb the excess vibrating energy from the synchronized system, at the onset of resonance.

Vibration Suppression of a Harmonically Forced Oscillator via a Parametrically Excited Centrifugal Pendulum

2021 ◽  
Author(s):  
Aakash Gupta ◽  
Wei-Che Tai
Keyword(s):  
Energy Transfer ◽  
Vibration Suppression ◽  
Primary Resonance ◽  
Harmonic Balance Method ◽  
Vibration Absorber ◽  
Vibration Mitigation ◽  
Nonlinear Energy Transfer ◽  
Forced Oscillator ◽  
Secondary Regime ◽  
Nonlinear Energy

Abstract Vibration suppression has been a widely studied topic for a long time, with various modifications in passive vibration mitigation devices to improve the efficacy. One such modification is the addition of the inerter. The inerter has been integrated into various vibration mitigation devices, whose mass amplification effect could be used to enhance the performance of dynamic vibration absorbers. In the current study, we consider an inerter based pendulum vibration absorber (IPVA) system and conduct a theoretical study on vibration suppression of the device. The IPVA system operates based on the principle of nonlinear energy transfer, wherein the energy of the primary structure is transferred into the pendulum vibration absorber. This is the result of parametric resonance of the pendulum, where the primary resonance of the system becomes unstable and a harmonic regime containing a frequency half the resonant frequency emerges (referred to as secondary regime). We use the harmonic balance method along with bifurcation analysis using Floquet theory to study the stability of primary resonance. It is observed that a pitchfork bifurcation and period-doubling bifurcation are necessary for nonlinear energy transfer to occur. Furthermore, we integrate the IPVA with a linear, harmonically forced oscillator to demonstrate its efficacy compared with a linear benchmark. We also examine the effects of various system parameters on the occurrence of the secondary regime. Moreover, we verify the nonlinear energy transfer phenomenon (due to the occurrence of the secondary regime) by numerical Fourier analysis.

Application of Tuned Vibration Absorber Concept to Blisk Ring Dampers: A Nonlinear Study

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Andrea Lupini ◽  
Mainak Mitra ◽  
Bogdan I. Epureanu
Keyword(s):  
Energy Transfer ◽  
Element Model ◽  
Ring Structure ◽  
Forced Response ◽  
Vibration Absorber ◽  
The Novel ◽  
Design Technique ◽  
Host Structure ◽  
Tuned Damper ◽  
Novel Design

AbstractIn this study, a novel design for ring dampers is proposed, where the concept of tuned vibration absorbers is leveraged to substantially increase damper effectiveness while minimizing potential stresses near the blade root. Tuned absorbers have been used in the past to reduce the forced response amplitudes of both mechanical and civil structures. The absorber natural frequency is tuned to the targeted frequency of the host structure where it is attached. The vibration reduction mechanism relies on energy transfer from the host structure to the absorber. The novel design technique proposed here uses a vibration absorber approach to achieve energy transfer from the blisk to the damper, which leads to larger damper motion. This enables energy dissipation due to friction, reducing vibrations even in blade-dominated modes. An academic finite element model of a blisk with a ring damper is used to demonstrate the novel tuned damper concept and design technique. The geometric mistuning of the damper due to the presence of a gap in the ring structure is also taken into account. The results demonstrate the validity of the proposed tuned damper concept, showing a substantial vibration amplitude reduction compared to the linear baseline results, in which the damper is not tuned or absent.

Application of Tuned Vibration Absorber Concept to Blisk Ring Dampers: A Nonlinear Study

2019 ◽  
Author(s):  
Andrea Lupini ◽  
Mainak Mitra ◽  
Bogdan I. Epureanu
Keyword(s):  
Energy Transfer ◽  
Element Model ◽  
Ring Structure ◽  
Forced Response ◽  
Vibration Absorber ◽  
The Novel ◽  
Design Technique ◽  
Host Structure ◽  
Tuned Damper ◽  
Novel Design

Abstract In this study, a novel design for ring dampers is proposed, where the concept of tuned vibration absorbers is leveraged to substantially increase damper effectiveness while minimizing potential stresses near the blade root. Tuned absorbers have been used in the past to reduce the forced response amplitudes of both mechanical and civil structures. The absorber natural frequency is tuned to the targeted frequency of the host structure where it is attached. The vibration reduction mechanism relies on energy transfer from the host structure to the absorber. The novel design technique proposed here uses a vibration absorber approach to achieve energy transfer from the blisk to the damper, which leads to larger damper motion. This enables energy dissipation due to friction, reducing vibrations even in blade dominated modes. An academic finite element model of a blisk with a ring damper is used to demonstrate the novel tuned damper concept and design technique. The geometric mistuning of the damper due to the presence of a gap in the ring structure is also taken into account. The results demonstrate the validity of the proposed tuned damper concept, showing a substantial vibration amplitude reduction compared to the linear baseline results, in which the damper is not tuned or absent.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

Sign in / Sign up

Export Citation Format

Share Document