TRANSIENT WAVE-PROPAGATION METHODS FOR DETERMINING THE VISCOELASTIC PROPERTIES OF SOLIDS

The following two solutions are proposed for deducing the viscoelastic properties of a solid from the change in the shape of a one-dimensional transient mechanical wave as it propagates through the medium: (i) The general solution:-the phase velocity and the attenuation coefficient are expressed in terms of the Fourier transforms of the pulse after two distances of travel, and (ii) A filter method. An experimental set-up is described. The results, which are obtained with no heating of the material, come within the audiofrequency range. This method fills a gap between the existing vibratory and ultrasonic methods.