The Dispersion of Laser-Induced Stress Waves in a Straight Cylindrical Rod

A Q-switched ruby laser with a pulse duration of approximately 50 ns has been used to initiate a broad-bandwidth stress pulse in a straight cylindrical steel waveguide of 1 cm diameter. The highly dispersed stress pulse has been recorded at a distance of 130 cm along the waveguide from the irradiated end and the stress, time profile analyzed by the method of stationary phase. First mode and second mode longitudinal waves and flexural waves have been recorded and the measured dispersion in each case compared with the predictions of the Pochhammer and Chree theory.