Cohesive granular materials subjected to particle swelling or shrinkage

For the simulations, we used the molecular dynamics method with a velocity-Verlet scheme for the integration of the equations of motion (Allen & Tildesley 1987). Cohesive interaction between two particles implies resistance to relative motion (normal displacement dn, tangential displacement dt and angular displacement γ) of two edge points belonging respectively to the two particles and coinciding initially with the contact point; Fig. 1(b).