Study on the Damping Effect of Particle Dampers considering Different Surface Properties
Table 2
Natural frequency and revised damping ratio of each case.
Case
Particles
Natural frequency (Hz)
Revised damping ratio (%)
Fill ratio (%)
Mass ratio (%)
Remarks
1
Empty
1.69
0.45
–
0.00
Free vibration
2
9 steel balls, D = 20 mm
1.65
1.41
70
10.99
Same fill ratio
3
9 alumina balls, D = 20 mm
1.68
0.95
70
4.72
4
14 glass balls, D = 15 mm
1.67
0.69
70
2.75
5
3 steel balls, D = 20 mm
1.68
0.79
24
3.66
Same mass ratio
6
7 alumina balls, D = 20 mm
1.67
0.61
55
3.66
7
19 glass balls, D = 15 mm
1.68
0.63
95
3.66
Fill ratio: projecting from the top to bottom, the ratio of the balls’ area to the bottom area of the container. Mass ratio: ratio of particle mass to frame mass.
