Constitutive Relations of Jammed Frictionless Granular Materials under   Oscillatory Shear
  We numerically investigate the rheological properties of jammed frictionless granular materials under an oscillatory shear in terms of our simulation of the distinct element method. It is demonstrated that the constitutive relation between the shear stress and the shear strain of grains strongly depends on the amplitude and the frequency of the oscillatory shear. For a small amplitude region, the granular material behaves as a visco-elastic material characterized by the Kelvin-Voigt model, while it behaves as a yield stress liquid for a large amplitude region. We find that the rheology of grains under the large amplitude oscillatory shear can be described by a phenomenological constitutive model. 
Michio Otsuki and Hisao Hayakawa
cond-mat.stat-mech cond-mat.soft