We present recent improvements of the modeling of the disruption of strength
dominated bodies using the Smooth Particle Hydrodynamics (SPH) technique. The
improvements include an updated strength model and a friction model, which are
successfully tested by a comparison with laboratory experiments. In the
modeling of catastrophic disruptions of asteroids, a comparison between old and
new strength models shows no significant deviation in the case of targets which
are initially non-porous, fully intact and have a homogeneous structure (such
as the targets used in the study by Benz&Asphaug (1999). However, for many
cases (e.g. initially partly or fully damaged targets, rubble-pile structures,
etc.) we find that it is crucial that friction is taken into account and the
material has a pressure dependent shear strength. Our investigations of the
catastrophic disruption threshold QD∗ as a function of target properties
and target sizes up to a few 100 km show that a fully damaged target modeled
without friction has a QD∗ which is significantly (5-10 times) smaller
than in the case where friction is included. When the effect of the energy
dissipation due to compaction (pore crushing) is taken into account as well,
the targets become even stronger (QD∗ is increased by a factor of 2-3).
On the other hand, cohesion is found to have an negligible effect at large
scales and is only important at scales ≲ 1km. Our results show the
relative effects of strength, friction and porosity on the outcome of
collisions among small (≲ 1000 km) bodies. These results will be used
in a future study to improve existing scaling laws for the outcome of
collisions (e.g. Leinhardt&Stewart, 2012).Comment: Accepted for publication in Planetary and Space Scienc