Modeling and evaluation of damping coefficient of eddy current dampers in rotordynamic applications

2016 ◽  
Vol 373 ◽  
pp. 52-65 ◽  
Author(s):  
J.G. Detoni ◽  
Q. Cui ◽  
N. Amati ◽  
A. Tonoli
Keyword(s):  
Eddy Current ◽  
Damping Coefficient ◽  
Evaluation Of Damping

A new type of damper combining eddy current damping with rack and gear

2020 ◽  
pp. 107754632093711
Author(s):  
Yafeng Li ◽  
Shouying Li ◽  
Jianzhong Wang ◽  
Zhengqing Chen
Keyword(s):  
Eddy Current ◽  
Permanent Magnets ◽  
Air Gap ◽  
Damping Coefficient ◽  
Apparent Mass ◽  
Damping Force ◽  
Equivalent Damping ◽  
Eddy Current Damping ◽  
New Type ◽  
Equivalent Damping Coefficient

A new type of damper combining eddy current damping with rack and gear, which can simultaneously export damping and inertial forces, is proposed. Eddy current damping with rack and gear is supposed to be installed between the building superstructure and foundation to mitigate the seismic response of the building. First, the concept of eddy current damping with rack and gear is introduced in detail and its apparent mass and equivalent damping coefficient are both theoretically investigated. Second, a prototype of eddy current damping with rack and gear is manufactured, and a series of tests on the prototype are carried out to verify its structural parameters. The experimental and theoretical results of the apparent mass of the prototype agree well with each other. The experimental result of the equivalent damping coefficient of the prototype is slightly lower than the numerical results obtained from COMSOL Multiphysics and its maximum relative differences are 11.3% and 13.6% for α = 0° and 45°, respectively. Third, detailed parametric studies on the damping force, including the effects of the thickness of the conductor plate, air gap, and number and location of permanent magnets, are conducted. The results show that the damping force keeps a linear relationship with velocity if it is lower than 0.15 m/s, and with the increase of the velocity, a strong nonlinear relationship between the damping force and the velocity is observed. The available maximum damping force can be increased by decreasing the thickness of the conductor plate and the air gap, increasing the number of permanent magnets. There is an optimal location about the permanent magnets for the available maximum damping force. In addition, the hysteretic curves of the eddy current damping with rack and gear obtained from the test indicate that the ability of energy dissipation is considerable.

scholarly journals Design and Development of Novel Semi Active Eddy Current Damper for Aerospace Applications

2019 ◽  
Vol 8 (10) ◽  
pp. 1589-1592
Keyword(s):  
Eddy Current ◽  
Plate Thickness ◽  
Damping Coefficient ◽  
Structural Vibration ◽  
Aerospace Applications ◽  
Damping Characteristics ◽  
Straight Line ◽  
Eddy Current Damping ◽  
Eddy Current Damper ◽  
Mechanical Devices

The structural vibration damping is of utmost priority and critical for electronic and mechanical devices used in aircraft and automobiles. A novel eddy current damper is designed and developed, thereby the damping characteristics were evaluated theoretically and experimentally to obtain an optimum value of damping coefficient to suppress the vibrations in the devices. After performing the various calculations, the desired value for “c” (eddy current damping co-efficient) is found out to be 150.93 Ns/m for a plate thickness of 3 mm, a current value of 3A, number of turns on the electromagnet was 1000. The graph of “c” vs “t” was found out to be a straight line. The nature of the graph obtained between amplitude of vibration vs time was similar to that of logarithmic decrement curve where the ratio of successive amplitudes remains constant. The value of damping coefficient ζ was found out to be in the desired range of the theoretical value

A Rotary Magnetic Damper or Brake Consisting of a Number of Sector Magnets and a Circular Conductor

1989 ◽  
Vol 111 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Kosuke Nagaya ◽  
Yasuo Karube
Keyword(s):  
Analytical Solution ◽  
Magnetic Flux ◽  
Eddy Current ◽  
Experimental Tests ◽  
Numerical Calculations ◽  
Damping Coefficient ◽  
Braking Force ◽  
Theoretical Results ◽  
Good Agreement

This paper is concerned with a method for analyzing a rotary magnetic damper (eddy current brake) consisting of a number of sector magnets and a circular conductor. The analytical solution to obtain an eddy current, a braking force, and a damping coefficient is obtained by dividing the magnetic flux into the narrow sectors. Numerical calculations have been carried out for the variation of the flux range, the position, and the number of the magnets. Experimental tests are also carried out to verify the present theoretical results. The theoretical results are in good agreement wtih the experimental ones.

Exact First Order Finite Element Modeling for Eddy Current NDE

1991 ◽  
Vol 3 (1) ◽  
pp. 235-253 ◽  
Author(s):  
L. D. Philipp ◽  
Q. H. Nguyen ◽  
D. D. Derkacht ◽  
D. J. Lynch ◽  
A. Mahmood
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Eddy Current ◽  
Element Modeling ◽  
First Order ◽  
Eddy Current Nde

MESSINE, a Parametric Three-Dimensional Eddy Current Model

2000 ◽  
Vol 12 (1) ◽  
pp. 65-86 ◽  
Author(s):  
R. La ◽  
B. Benoist ◽  
B. de Barmon ◽  
M. Talvard ◽  
R. Lengelle ◽  
...  
Keyword(s):  
Eddy Current ◽  
Current Model ◽  
Three Dimensional
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