Dynamics of Machines - Part II - IFS.pdf

1.7.9 Resonance – Experimental Analysis in Time Domain
(a) Amplitude [m/s 2 ]
1
0
−1
x Signal 10−5
2
(a) in Time Domain − (b) in Frequency Domain
−2
0 5 10 15
time [s]
20 25 30
(b) Amplitude [m/s 2 ]
4
3
2
1
x 10 −6
0
0 5 10 15 20 25
frequency [Hz]
(a) Amplitude [m/s 2 ]
1
0
−1
x Signal 10−5
2
(a) in Time Domain − (b) in Frequency Domain
−2
0 5 10 15
time [s]
20 25 30
(b) Amplitude [m/s 2 ]
8
6
4
2
x 10 −6
0
0 5 10 15 20 25
frequency [Hz]
Figure 31: Resonance phenomena due to the excitation force with frequency around the natural
frequency of the mass-spring system: 2 D.O.F. system with the natural frequencies of 0.62 Hz
and 4.59, excited by the shaker – Spring-mass system ”A” with three masses m = m1+m2+m3 =
0.573 Kg fixed at the beam length L2 = 0.610 m and three additional masses m = m4+m5+m6 =
0.573 Kg fixed at the middle L1 = 0.310 m resulting in two natural frequencies of 0.62 Hz and
4.60 Hz.
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