In discrete element (DEM) simulations of hard particles with soft contacts, for elongated particles the noise in theangular motion can introduce force changes which act on the rectilinear degrees of freedom for elastic interactionsalone. At least for round particles with tangential forces (friction), this problem exists also. Independent dampingforces at the particle contacts can neither damp away the motion due to these force uctuations nor can theydamp out the noise in the angular degrees of freedom. The resulting vibration leads to a slow creep downwards forthe center of mass of granular aggregates. We discuss the similarities and differences for the damping of rectilinearand angular degrees of freedom and approaches for a rotational damping to decrease such creep.
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