0
Research Papers

Effect of Modes Inside or Outside the Studied Band on Accuracy of Decay Rate Method in Vibration Damping Test

[+] Author and Article Information
Banghui Yin

School of Marine Science and Technology,
Northwestern Polytechnical University,
Xi'an 710072, China
e-mail: yinbanghui1982@yahoo.com

Minqing Wang

School of Marine Science and Technology,
Northwestern Polytechnical University,
Xi'an 710072, China

1Corresponding author.

Contributed by the Technical Committee on Vibration and Sound of ASME for publication in the JOURNAL OF VIBRATION AND ACOUSTICS. Manuscript received October 27, 2014; final manuscript received April 15, 2015; published online June 16, 2015. Assoc. Editor: Corina Sandu.

J. Vib. Acoust 137(5), 051015 (Oct 01, 2015) (7 pages) Paper No: VIB-14-1405; doi: 10.1115/1.4030664 History: Received October 27, 2014; Revised April 15, 2015; Online June 16, 2015

The band-averaged damping is determined by modal damping of the modes inside/outside the frequency band. In this paper, the effect of modes inside/outside a frequency band on the accuracy of the decay rate method (DRM) in vibration damping test was studied. First, to study the effect of modes inside a frequency band on the accuracy of DRM, the relationship between the damping loss factors (DLFs) from DRM and that from statistical energy analysis (SEA) was deduced theoretically. As shown from the analytical results, the DLF from DRM is close to that from SEA when the differences of the modal loss factors of the modes in the band are small; while the DLF from DRM is much less than that from the SEA if the differences of the modal loss factors in the band are large. Second, the influence of energy leakage from modes outside a frequency band on damping test results was studied numerically. The study reveals that when there is no mode in a frequency band, the effect of the mode outside the band on the decay rate (DR) of DRM is only related with the DR of the mode instead of the location of the mode; while when the band contains modes, the DR of DRM is influenced by the DR, amplitude, and location of the modes outside the band and the influence has a positive variation with DR, amplitude, and distance from the mode to the band. Finally, plate's transient impact response data from finite element simulation were used to verify the relevant conclusions.

FIGURES IN THIS ARTICLE
<>
Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Lyon, R. H., and Madanik, G., 1961, “Power Flow Between Linearly Coupled Oscillators,” J. Acoust. Soc. Am., 34(5), pp. 623–639. [CrossRef]
Wu, L., and Ågren, A., 1997, “A Study of the Initial Decay Rate of Two-Dimensional Vibrating Structures in Relation to Estimates of Loss Factor,” J. Sound Vib., 206(5), pp. 663–684. [CrossRef]
Sheng, M., and Wang, M., 2001, “On Fairly Accurately Determining the Loss Factor of Two-Mode System in Steady Vibration With the Attenuation Method,” J. Northwest. Polytech. Univ., 19(1), pp. 130–135.
Bloss, B. C., and Rao, M. D., 2005, “Estimation of Frequency-Averaged Loss Factors by the Power Injection and the Impulse Response Decay Methods,” J. Acoust. Soc. Am., 117(1), pp. 240–249. [CrossRef] [PubMed]
Clarkson, B. L., and Pope, R. J., 1981, “Experimental Determination of Modal Densities and Loss Factors of Flat Plates and Cylinders,” J. Sound Vib., 77(4), pp. 535–549. [CrossRef]
Gade, S., and Herlufsen, H., 1994, “Digital Filter vs FFT Techniques for Damping Measurements,” Brüel Kjær Tech. Rev., 1, pp. 1–42. http://www.bksv.com/doc/bv0044.pdf
Ungar, E. E., Edward, J., and Kerwin, M., 1962, “Loss Factors of Viscoelastic Systems in Terms of Energy Concepts,” J. Acoust. Soc. Am., 34(7), pp. 954–957. [CrossRef]
Feeny, B. F., 2009, “Estimating Damping Parameters in Multi-Degree-of-Freedom Vibration Systems by Balancing Energy,” ASME J. Vib. Acoust., 131(4), p. 041005. [CrossRef]
Lyon, R. H., 1975, Statistical Energy Analysis of Dynamical System: Theory and Application, MIT Press, Cambridge, MA.
Bies, D. A., and Hamid, S., 1980, “In Situ Determination of Loss and Coupling Loss Factors by the Power Injection Method,” J. Sound Vib., 70(2), pp. 187–204. [CrossRef]
Wang, M., Sheng, M., and Sun, J., 2000, “Theoretical Study of Vibration Energy Loss in Two-Coupled-Mode System,” J. Northwest. Polytech. Univ., 18(4), pp. 553–556.
Sheng, M., 2001, “Influence of Modes on the Damping of Frequency Band,” Tech. Acoust., 20(2), pp. 56–58.
Jacobsen, F., and Rindel, J. H., 1987, “Letters to the Editor: Time Reversed Decay Measurements,” J. Sound Vib., 117(1), pp. 187–190. [CrossRef]
Schroeder, M. R., 1965, “New Method of Measuring Reverberation Time,” J. Acoust. Soc. Am., 37(3), pp. 409–412. [CrossRef]
Morsse, P. M., and Ingard, K. U., 1984, Theoretical Acoustics, Science Press, Beijing.
Rao, S. S., and Yap, F. F., 1995, Mechanical Vibrations, Addison-Wesley, New York. [PubMed] [PubMed]

Figures

Grahic Jump Location
Fig. 1

Procedure for DLFs determined from DRM

Grahic Jump Location
Fig. 2

Energy level decay curve when γ1 = 100 dB/s and γ2 = 500 dB/s

Grahic Jump Location
Fig. 3

Energy level decay curve when A1 = 1 m, A2 = 1 m, γ1 = 100 dB/s, and γ2 = 700 dB/s

Grahic Jump Location
Fig. 4

Time history data of the simulated impact

Grahic Jump Location
Fig. 5

Energy level decay curve of 125 Hz one-third octave band and line fitting for initial DR

Grahic Jump Location
Fig. 6

Energy level decay curve of 80 Hz one-third octave band and line fitting for the initial DR

Grahic Jump Location
Fig. 7

Energy level decay curve of 160 Hz one-third octave band and line fitting for the initial DR

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In