Bending vibration measurement on rotors by laser vibrometry

A new technique is proposed for noncontact measurement of bending vibration directly from a rotating component. This notoriously difficult and previously unattained measurement is a further development of laser Doppler vibrometry. Simultaneously the technique provides an accurate measure of shaft torsional vibration in situations in which measurements of torsional vibration have shown significant sensitivity to bending vibration. Experimental results validate the theory developed, and a conservative estimate of the minimum measurable bending vibration is made at 20 millidegrees.