Some wave-propagation experiments in plasteline-clay rods

Compressional stress pulses have been propagated in plasteline-clay rods by detonating small charges of lead azide at one end. A capacitance gage at the other end was used to measure particle displacement associated with the pulses and the particle velocity was obtained by differentiation. The shapes and amplitudes of the pulses were determined in separate experiments using composite clay-steel rods where the steel acted, in effect, as a pressure transducer. The techniques employed permitted comparatively accurate determination of some aspects of the dynamic behavior of clay. On the basis of preliminary results, the behavior of clay has been compared to that of a linear viscoelastic solid with the tentative goal of studying the validity of a viscoelastic constitutive model.