DEM modelling of shear localization in a plane Couette shear test of granular materials

This paper presents a numerical study of shear localization in granular materials based on a discrete element method. The plane Couette shear test is proposed for this purpose. A numerical model is established to simulate the test. With the flexible side boundaries, it is demonstrated that the plane Couette shear state can be achieved within a granular sample of limited length, and a shear band parallel to the shear direction can be obtained. Numerical results are also presented to show the formation and the development of the shear band. A homogenization procedure is employed for presenting the variation of the field variables such as stress components, the couple stress, the void ratio and the grain rotation. The evolution and the spatial distribution of these quantities are qualitatively in accordance with the Cosserat continuum model predictions. The numerical results also indicate that the Cosserat effect plays a vital role in shear localization zone.