PRECURSOR ATTENUATION IN ELASTICVISCOELASTIC MATERIALS.
Rept. no. 2,
STANFORD UNIV CALIF DIV OF ENGINEERING MECHANICS
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A plane shock wave of intermediate intensity in a metal is generally preceded by an elastic wave known as the elastic precursor. A theoretical analysis of the decay of this wave with distance of travel is given, based on a constitutive equation of the elastic visco-plastic type often referred to as rate sensitive plasticity. It is shown that the predicted decay of the elastic precursor by this theory is in good agreement with published experimental measurements of the attenuation with distance of the precursor wave in Armco iron and that these measurements provide sufficient data for the determination of the parameters which appear in the theory. Accordingly such attenuation measurements in other metals could lead to an increased understanding of the influences of strain rate sensitivity on the plastic behavior of these metals. While the elastic visco-plastic constitutive equation is generally motivated on phenomenological grounds. it is shown here that it can be related to the physical theory of creep in metals. Author