Dislocation Glides in Monolayered Granular Media: Effect of Lattice Constant

A recent study demonstrated that granular crystals containing a single dislocation exhibit dislocation glide analogous to that observed in atomic-scale crystals, resulting in plastic deformation at yield stresses several orders of magnitude lower than those of dislocation-free crystals. The yielding behavior strongly depends on the interparticle friction coefficient $\mu$: dislocation glide occurs for friction coefficients below a critical value $\mu_c$, while crystalline order deteriorates above $\mu_c$. In this work, we use discrete element method simulations to systematically investigate how the lattice constant, which determines the interparticle spacing and is a fundamental parameter in microscopic crystalline solids, and the friction coefficient $\mu$ influence the yielding behavior in monolayered granular crystals with dislocation. By decreasing the lattice constant, we find an increase in the critical friction coefficient $\mu_c$, allowing dislocation glide to persist at higher friction values. Furthermore, we observe a linear scaling of yield stress with normal stress, except at extremely low friction coefficients.