Dave Looman
Ansys Employee

It still appears you are starting the analysis with the cylinder far away from the target.  Are recommendation has been to model the cylinder in contact with the target.  Nothing is happening in the time before impact so it is wasted computation, but more important there is a risk the cylinder will over-penetrate the target.  As mentioned, plasticity frequently occurs in impact problems.  In the APDL Verification Manual, VM265 is a very plastic impact analysis of a copper cylinder.