Force-chain identification in quasi-2D granular systems

Understanding the properties of force-chains is essential in understanding the physical and mechanical properties of granular materials. The key is to identify force-chains. In this study, we describe a systematic method to identify individual force-chains in 2D granular systems under different external load-pure shear or isotropic compression, where bi-disperse photo-elastic particles were used in order to measure vector contact forces between particles. Using this method, we studied the statistics of force-chain size distribution in these two systems: in pure shear, the distribution shows a fat tail that deviates from an exponential distribution function, whereas in isotropic compression, the distribution decays exponentially. In addition, we also investigated the dependence of various force-chain statistics on two main parameters defined in the force-chain identification algorithm.