We perform molecular dynamic (MD) simulations of frictional non-thermal
particles driven by an externally applied shear stress. After the system jams
following a transient flow, we probe its mechanical response in order to
clarify whether the resulting solid is 'fragile'. We find the system to respond
elastically and isotropically to small perturbations of the shear stress,
suggesting absence of fragility. These results are interpreted in terms of the
energy landscape of dissipative systems. For the same values of the control
parameters, we check the behaviour of the system during a stress cycle.
Increasing the maximum stress value, a crossover from a visco-elastic to a
plastic regime is observed.Comment: 6 pages, 9 figures, accepted in Granular Matter on 01-02-201
