A method to extract the mechanical properties of particles in collision based on a new elasto-plastic normal force-displacement model

We present a general method to extract the elasto-plastic mechanical properties such as the coefficient of restitution, Young's modulus, Poisson's ratio, and the yield stress of granular materials from simple experimental measurements. These mechanical properties are important in the simulation of granular flows, but are not readily available and/or cannot be measured through direct experiments. The method developed here is based on the new elasto-plastic normal force-displacement (NFD) model [presented in Proceedings of the Royal Society of London, Series A 455 (1999b) 4013]. Using the Vu-Quoc and Zhang NFD model to simulate both the dropping test and the compression test of a particle, the mechanical properties of the particle can be extracted by minimizing, in the least-square sense, the difference between the experimental and simulated force-displacement relation. An application of the proposed method to soybeans is presented. (C) 2002 Published by Elsevier Science Ltd.