CREEP, POWER LAW
Diffusion creep breaks down when stress and strain rates are increased
sufficiently so that dislocations start to appear in a considerable number
inside the individual grains of the creeping material. This is when first
dislocation climb and later dislocation glide creep mechanisms are
activated. Power law creep is believed to be governed by dislocation climb
mechanism. Power law creep makes the deformation easier when the rocks
cannot deform in linearly viscous manner. If n=1 in the equation then the
material behaves as a Newtonian viscous one.
|