Improved Concept and Model of Eddy Current Damper
- 3 November 2005
- journal article
- Published by ASME International in Journal of Vibration and Acoustics
- Vol. 128 (3), 294-302
- https://doi.org/10.1115/1.2172256
Abstract
When a conductive material experiences a time-varying magnetic field, eddy currents are generated in the conductor. These eddy currents circulate such that they generate a magnetic field of their own, however the field generated is of opposite polarity, causing a repulsive force. The time-varying magnetic field needed to produce such currents can be induced either by movement of the conductor in the field or by changing the strength or position of the source of the magnetic field. In the case of a dynamic system the conductor is moving relative to the magnetic source, thus generating eddy currents that will dissipate into heat due to the resistivity of the conductor. This process of the generation and dissipation of eddy current causes the system to function as a viscous damper. In a previous study, the concept and theoretical model was developed for one eddy current damping system that was shown to be effective in the suppression of transverse beam vibrations. The mathematical model developed to predict the amount of damping induced on the structure was shown to be accurate when the magnet was far from the beam but was less accurate for the case that the gap between the magnet and beam was small. In the present study, an improved theoretical model of the previously developed system will be formulated using the image method, thus allowing the eddy current density to be more accurately computed. In addition to the development of an improved model, an improved concept of the eddy current damper configuration is developed, modeled, and tested. The new damper configuration adds significantly more damping to the structure than the previously implemented design and has the capability to critically damp the beam’s first bending mode. The eddy current damper is a noncontacting system, thus allowing it to be easily applied and able to add significant damping to the structure without changing dynamic response. Furthermore, the previous model and the improved model will be applied to the new damper design and the enhanced accuracy of this new theoretical model will be proven.Keywords
This publication has 15 references indexed in Scilit:
- Vibration Suppression Using Eddy Current DamperTransactions of the Korean Society for Noise and Vibration Engineering, 2003
- THEORETICAL COMPARISON OF MOTIONAL AND TRANSFORMER EMF DEVICE DAMPING EFFICIENCYJournal of Sound and Vibration, 2000
- Electromagnetic forces for a new vibration control system: experimental verificationSmart Materials and Structures, 2000
- Eddy current damping of a magnet moving through a pipeAmerican Journal of Physics, 1998
- A UNIFIED MATRIX POLYNOMIAL APPROACH TO MODAL IDENTIFICATIONJournal of Sound and Vibration, 1998
- Vibration Control System Using Electromagnetic ForcesJournal of Intelligent Material Systems and Structures, 1997
- Magnetic damping: Analysis of an eddy current brake using an airtrackAmerican Journal of Physics, 1996
- Analysis and experiment of dynamic deflection of a thin plate with a coupling effectIEEE Transactions on Magnetics, 1992
- Analysis of a coupled problem: the FELIX cantilevered beamIEEE Transactions on Magnetics, 1990
- Permanent Magnet Linear Motors Used as Variable Mechanical Dampers for Vehicle SuspensionsVehicle System Dynamics, 1989