[OrthoDan]

Pro-Mechanica is limited to static analysis, so whatever you might learn about impact in a simulation will be an approximation. The CMU tutorial posted by PTC_FRC has a nice example of building a beam-type finite element model that would be a reasonable approach for welded aluminum frames, which many FRC teams use. You need to be sure to place nodal points (at the ends of beam elements) at locations where you either want to constrain the structure or apply a load. For impact protection, avoid long unsupported spans of thin walled aluminum tubing. Cross-bracing will help avoid impact related permanent bending of your frame.