Asymmetry of the stress tenor in granular materials

•This paper uses DEM and averaging method to study the asymmetry of stress tensor in granular materials.•A graphical tool is developed to show the asymmetric stress.•The relationship between length scale in a constitutive model and the stress asymmetry is discussed.•The averaged stresses in different locations and time periods are shown.

One of the basic assumptions of the micropolar theory is that the stress tensor is not symmetric. In this paper, asymmetry of the stress tensor is studied with discrete element method and averaging method. The change of the skew symmetric part of an asymmetric tensor with the rotation of the coordinate system is shown graphically. Averaging method is used to obtain stress tensor from a DEM simulation of biaxial test. Stress asymmetries at different locations, scales and time steps are studied. The importance of the asymmetric stress for setting up a constitutive model for granular materials is discussed.

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