Evaluation of Volume Variation Partition: the Breathing Coefficient and its Application on Uniaxial Monosized Disc Packing Swelling

Abstract

An analysis of the general concept of volume variation partition of a porous body is presented, introducing the breathing coefficient, defined as the ratio of two volume variations. Considering a total volume of a porous body, composed of solid volume and ``void'' volume, this ratio can be used to evaluate the distribution of a volume variation into both others. A full description of its physical interpretation is detailed, together with an uncertainty analysis that specifies precautions about its use. As an example of application, a case study of 2D monosized disc packing swelling is developed. The analytical model reveals the presence of minimisation points of the breathing coefficient dependent on the initial granular organisation, showing possible ways to minimise the breathing of a granular material.