Time-average TV holography for vibration fringe analysis.
Time-average TV holography is widely used method for vibration measurement. The method generates speckle correlation time-averaged J0 fringes that can be used for full-field qualitative visualization of mode shapes at resonant frequencies of an object under harmonic excitation. In order to map the amplitudes of vibration, quantitative evaluation of the time-averaged fringe pattern is desired. A quantitative evaluation procedure based on the phase-shifting technique used in two beam interferometry has also been adopted for this application with some modification. The existing procedure requires a large number of frames to be recorded for implementation. We propose a procedure that will reduce the number of frames required for the analysis. The TV holographic system used and the experimental results obtained with it on an edge-clamped, sinusoidally excited square aluminium plate sample are discussed.
Kumar
Upputuri Paul
UP
Applied Optics Laboratory, Department of Physics, Indian Institute of Technology Madras, Chennai-600036, India.
Kalyani
Yanam
Y
Mohan
Nandigana Krishna
NK
Kothiyal
Mahendra Prasad
MP