Vibration measurement using additive speckle interferometry

Liusheng Wang*, Pavel Fomitchov, Sridhar Krishnaswamy

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapter

Abstract

A method for obtaining structural vibration amplitudes quantitatively is proposed based on the stroboscopic speckle interferometer. The technique requires five frames of additive speckle patterns: the first one (S0) taken with the laser illumination pulsed at instants when the vibration achieves its two zero amplitude positions within one sinusoidal vibration cycle of the specimen; and the remaining four (S1 through S4) taken with the illumination pulses arranged at times when the vibration is at its maximum and minimum amplitudes. During the acquisition of speckle patterns S1 through S4, the phase of the reference beam is appropriately shifted between the two pulses within each vibration cycle. The last four speckle patterns are then subtracted from the first one to yield four correlation fringe patterns with relative phase shifts of 0, π/2, π and 3π/2 respectively. These fringe patterns are then utilized to derive a phase map using a four-step phase calculation algorithm and finally the vibration amplitude and the sign of the vibrational nodes can be readily obtained from the phase map quantitatively. Results have been obtained using a speckle shearographic setup for the vibration measurement of a flat bottom-holed aluminum specimen vibrating at different frequencies.

Original languageEnglish (US)
Title of host publication15th Biennial Conference on Mechanical Vibration and Noise
EditorsK.W. Wang, B. Yang, J.Q. Sun, K. Seto, K. Yoshida, al et al
Edition3 Pt C
StatePublished - Dec 1 1995
EventProceedings of the 1995 ASME Design Engineering Technical Conference. Part C - Boston, MA, USA
Duration: Sep 17 1995Sep 20 1995

Publication series

NameAmerican Society of Mechanical Engineers, Design Engineering Division (Publication) DE
Number3 Pt C
Volume84

Other

OtherProceedings of the 1995 ASME Design Engineering Technical Conference. Part C
CityBoston, MA, USA
Period9/17/959/20/95

ASJC Scopus subject areas

  • Engineering(all)

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  • Cite this

    Wang, L., Fomitchov, P., & Krishnaswamy, S. (1995). Vibration measurement using additive speckle interferometry. In K. W. Wang, B. Yang, J. Q. Sun, K. Seto, K. Yoshida, & A. et al (Eds.), 15th Biennial Conference on Mechanical Vibration and Noise (3 Pt C ed.). (American Society of Mechanical Engineers, Design Engineering Division (Publication) DE; Vol. 84, No. 3 Pt C).