Application of pulsed holographic interferometry to the measurement of propagating transverse waves in beams

The technique of double-exposure holographic interferometry was used to record transverse waves propagating in a long beam. The wave was initiated by striking the beam in the center with a ballistic pendulum. Pulsedlaser interferograms were obtained which showed the bending waves at three different times after the initiation of impact for three different experiments. From the interferograms, plots of the transverse displacement vs. distance along the beam were obtained. The experimental data compared favorably with analytical results for the problems. The experimental technique, differential interferometry, was also introduced to facilitate measurement of largeamplitude motions using holography.