3.2.1 Slow dynamic effects

Slow dynamics is by far the most typical characteristic of the nonclassical NMEM. It refers to the logarithm dependence recovery of the elastic modulus to the original initial value (i.e., at rest) after being excited and therefore softened by a large amplitude strain. The log-time evolution of the elastic modulus resembles to a creeplike behavior observed in quasi-static experiments. However, it is important to note that slow dynamics is more likely a new creep behavior due to the fact that modulus is not following the symmetry of the strain. Furthermore, contrary to creep experiments, slow dynamics is a reversible and repeatable behavior, and observations on rocks and some damaged metals are performed at dynamic strain levels two or three orders of magnitude below those of a typical creep experiment. Slow dynamics includes two different scale mechanisms: conditioning and relaxation.
