The old NCAC website with the Finite Element models is unfortunately offline since a while.
( http://www.ncac.gwu.edu/vml/models.html )
But there is a new/other one ( https://www.ccsa.gmu.edu/models/ )!
It does not have all the old models but there are a couple of new models that you can maybe use. Note that for some of the models there are coarse and detailed versions.
These models are however for LS-DYNA, but with some work you can use Altair Hypermesh or another Pre-Processor, to convert it to RADIOSS input deck format.