Why do naval jet aircraft need to have strengthened undercarriages?
The landing on carrier is indeed hard. The reason is not the deceleration (which is handled by the hook), but the touch-down. Since the deck is short, the wires can't be spaced very far apart, so the aircraft must touch down very precisely. Since the precision is better at steeper angle, the aircraft landing on carrier do not flare. At all. So they hit the deck at more than twice the vertical speed compared to typical landing on decent runway.