Dear Bingley: I never heard "nave" used as "hub" before, but my dictionary gives it a second word with that meaning.
I wonder if it is in any way related to "navel".
A better way of fighting elephants was described in life of Metellus, a couple hundred years after Pyrrhus. He had advancing elephants attacked with spears, causing them to turn and trample the Carthaginian infantry, leading to Roman victory.