  Using a simple and generic molecular dynamics model, we study the damage in a
disc of interacting particles as the disc fragments upon impact with a wall.
The damage, defined as the ratio of the number of bonds broken by the impact to
the initial number of bonds, is found to increase logarithmically with the
energy deposited in the system. This result implies a linear growth with damage
for the total number of fragments and for the power law exponent of the
fragment size distribution.
