In this paper, a new method for simultaneously estimating Coulomb and viscous friction parameters from the free vibration of a damped oscillator is put forward. In the method, the nonlinear vibration equation with Coulomb and viscous friction is transformed into a linear procedure with equivalent viscous damping which is a function of velocity. The proposed method works well with both the displacement and velocity response data, while the case of zero velocity is not considered. From the displacement decaying curve, the equivalent viscous damping ratios are obtained by means of the local exponential fitting method, and different velocities corresponding to the equivalent viscous damping ratios are also obtained from the velocity decaying curve. Then, according to the relationship between the equivalent viscous damping ratio and the velocity, the Coulomb friction and the viscous damping are achieved using the least square method. The validity and accuracy of the proposed method are demonstrated through good simulation results.

1.
Den Hartog
J. P.
,
1931
, “
Forced Vibration with Combined Coulomb and Viscous Damping
,”
ASME J. of Vibration and Acoustics
,
53
, pp.
107
115
.
2.
Hundal
M. S.
,
1979
, “
Response of a Base Excited System with Coulomb and Viscous friction
,”
Journal of Sound and Vibration
,
64
, pp.
371
378
.
3.
Er
G.-K.
, and
Iu
V. P.
,
2000
, “
Stochastic Response of Base-Excited Coulomb Oscillator
,”
Journal of Sound and Vibration
,
233
, pp.
81
92
.
4.
Cheng
Gong
, and
Zu
Jean W.
,
2002
, “
Two-Frequency Oscillation with Combined Coulomb and Viscous Frictions
,”
ASME J. of Vibration and Acoustics
,
124
, pp.
537
544
.
5.
Jacobsen, L. S., and Ayre, R. S., 1958, Engineering Vibrations, McGraw-Hill, New York.
6.
Feeny
B. F.
, and
Liang
J. W.
,
1996
, “
A Decrement Method for The Simultaaneous Estimation of Coulomb and Viscous Friction
,”
Journal of Sound and Vibration
,
195
, pp.
149
154
.
7.
Liang
J. W.
, and
Feeny
B. F.
,
1998
, “
Identifying Coulomb and Viscous Friction from Free-Vibration Decrements
,”
Nonlinear Dynamics
,
16
, pp.
337
347
.
8.
Dai, D.P., 1986, Technology of Damping for Vibration and Noise Reduction, Xi’an University Press, Xi’an, pp. 25–34.
9.
Audenino
A. L.
,
Zanetti
E. M.
, and
Calderale
P. M.
,
1998
, “
Assessment of Internal Damping in Uniaxially Stressed Metals: Exponential and Autoregressive Methods
,”
ASME J. of Dynamic Systems, Measurement, and Control
,
120
, pp.
177
184
.
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