The acousto-elastic effect in a rolled plate of copper was studied experimentally from the measurements of the velocity and the amplitude of ultrasonic waves. A specimen with its axis perpendicular to the rolling direction was prepared from the plate for uni-axial tension tests, and ultrasonic waves with the frequency of 5MHz were transmitted into it along the thickness direction. For the velocity measurement, the sing-around method (S. A. method) was used. The results show that stress causes a linear change in all three velocities of independent waves, two of which are transverse waves polarized along and perpendicular to the stress axis. The amplitude of a transverse wave was also measured to analyze the birefringence due to structural anisotropy and stress (P. H. method). This shows that the anisotropy is slight, and that the velocity difference of two polarized transverse waves varies in proportion to the stress applied. Thus it is ascertained that the acousto-elastic results obtained by the two methods are consistent quantitatively, and that the copper plate used in the present work shows a linear stress-dependency of velocity as seen in alminium and steel.
