I'm sure there are documents on the web that can provide some guidance in designing structures for impact. You might want to locate one of the government MIL-STD specifications on that topic. They usually explain the theory behind what the standard is designed for.
As for reference texts try...
The three FEA packages mentioned are quite capable but they have a substantial learning curve and cost lots of money.
How precise does your analysis have to be? There are a number of formulas used in shock and vibration analysis to size energy absorbing components based on impact forces...
Find it hard to believe that ANSYS cannot provide the elements required to model a rotating shaft simply- supported by a bearing. You may need to examine the problem more carefully in order to extract just what it is that should be modeled. Using FEA technigues requires a surprising amount of...
