| Summary: | Experiments were made in the laboratory to determine the feasibility
of adapting to the measurement of the shear elastic properties of
sediment- like materials techniques already proven for use on viscoelastic
liquids. A torsional transducer attached to an aluminum rod was immersed
in a Kaolin sediment and driven in either a pulse-echo mode or
a standing wave mode. Both techniques were found to be satisfactory
and in good agreement over the limited frequency range (38 to 39 kHz)
imposed by the characteristics of the transducer-rod combination. In
the pulsed mode, measurement of the changes in attenuation and phase of
the pulses (tone-bursts) in the rod when the rod is immersed in the
sediment allow calculation of the real and imaginary parts of the complex
shear modulus. In the resonant mode, measurement of the changes
in resonant frequency and the electrical resistance at resonance upon
immersion allow a similar calculation of the complex shear modulus. It
was found that a complex shear modulus did exist for the sediment investigated,
thus indicating that the sediment displays both viscous and
elastic properties. Furthermore, the measured properties were found to be a sensitive function of sediment compaction.
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