title: Strain-rate-dependent model for the dynamic compression of elastoplastic spheres.
abstract: We present a force-displacement contact model for the compressive loading of elastoplastic spheres. This model builds from the well known Hertz contact law for elastic, quasistatic compression to incorporate a material's strain-rate-dependent plasticity in order to describe collisions between particles. In the quasistatic regime, finite-element analysis is used to derive an empirical function of the material properties. A Johnson-Cook strain rate dependence is then included into the model to study dynamic effects. We validate the model using split Hopkinson bar experiments and show that the model can accurately simulate the force-displacement response of strain-rate-dependent elastoplastic spheres during dynamic compression and unloading.
authors.affiliation: Graduate Aerospace Laboratories (GALCIT), California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Hayden A
authors.initials: HA
authors.lastname: Burgoyne
authors.affiliation: Graduate Aerospace Laboratories (GALCIT), California Institute of Technology, Pasadena, California 91125, USA and Chair in Mechanics and Materials, ETH Zurich, Zurich 8092, Switzerland.
authors.forename: Chiara
authors.initials: C
authors.lastname: Daraio