Contact behavior of idealized granules bonded in two different interparticle distances: An experimental investigation

This paper presents an experimental investigation on contact behavior of idealized granules bonded in two different interparticle distances, which can be used in discrete element modelling of natural sands featured with interparticle cementation. Firstly, by using the designed specimen preparation devices, two aluminum rods are glued together by adhesive material in two different pre-defined modes, namely thin bond mode and thick bond mode representing different bond thickness between particles. Then, by employing the novel auxiliary loading devices, the mechanical behavior of contact between the bonded rods is obtained while different kinds of forces (i.e., normal force, shear force and moment) are applied in different ways. The experimental results show that both the tension strength and ductility increase with the increasing of bond thickness. However, the force–displacement relationship in compression is characterized with strain hardening in the thin bond mode but strain softening in the thick bond mode. In addition, the peak shear strength and peak rolling resistance increase with the increasing of normal force in the thin bond mode, while they increase with the normal force at first, and then decrease in the thick bond mode. Moreover, the strength envelope is an elliptical paraboloid in the thin bond mode but a teardrop in the thick bond mode in the shear force-normal force-moment space.