On Slow Dynamic Elasticity at short times

Abstract

It has been reported that slow dynamic nonlinear elastic relaxations, widely thought to proceed in proportion to the logarithm of time since mechanical conditioning ceases, recover at a diminished rate at early times, with a time of transition that varies with the grain size of the material. Here we recount new observations at short times, in the single bead system, in cement paste and in sandstone and mortar. Notwithstanding the limits imposed by finite duration ring down such that the effective instant of conditioning cessation is imprecise, and the corresponding ambiguity as to the time that relaxation begins, we find no reliable sign of such a transition, even in samples of large grain size mortar similar to those described elsewhere as having clear and late cutoffs.