Tuning mechanical response in granular layers by adding rigid particle channel

Abstract

The inhomogeneity of spatial packing by particles with different physical properties can significantly affect mechanical properties of granular packings. In this paper, a new approach by adding rigid particle channel is put forward to tune the mechanical response of granular layers induced by external loading. Based on the single-layer channel model, a phase diagram is firstly proposed to describe the crossover of mechanical response between a single-peaked and double-peaked feature, in which the tunable range of external loading and effective region of channel position are two key factors that reflect the tuning effect of this approach. Its tuning mechanism is further explored based on the variations of propagating feature of contact forces, and a linear function is proposed to predict the optimal position of the channel in systems with different sizes. Furthermore, the dependence of tuning effect on the spatial configuration and the number of rigid particle layers is also discussed in a double-layer and multi-layer rigid particle channel models, which can obviously improve the tunable effect but also undergo different tuning processes. By adding different rigid particle channels to actively change propagation paths of contact forces and weaken the anisotropy in vertical stress field within granular system, it has been verified that this approach is feasible to enhance the elasticity of whole system and tune its mechanical response.