Correlation of fabric tensors for granular materials using 2D DEM

Abstract

Soil fabric anisotropy can be quantitatively assessed by means of fabric tensors introduced as internal variables in constitutive models and defined by unit vectors along the directions of different orientation microstructural entities such as particle long axes, inter-particle contact normal vectors and void vectors. The most common choice is a fabric tensor based on contact normal directions. However, contact normal directions are more difficult to determine experimentally, due to difficulties associated with accurate measurement of tangent contact planes. The main scope in this study is to seek for possible correlations for fabric tensors defined using different fabric entities, i.e., contact normal, void and particle orientation vector directions, and based on this correlation to suggest the two latter instead of the first one because of the easiness of their measurements. The void fabric is defined using a very recent contribution of the authors concerning a modified and a novel approach of the scan line method for the determination of appropriate void vectors by means of 2D discrete element method analysis. In this very recent work of the authors, a first qualitative correlation was detected between contact normal and void fabric for both the void fabric tensors used therein. Given that this observation concerned only one 2D test, the current work aims at presenting an extended parametric analysis on the correlation of fabric tenors for all the above-mentioned fabric entities.