Is it possible to break your opponent's armor more than once per match?
No. After your armor breaks in a round, it does not come back for the next round. Also, your character has an armored and unarmored state, with no third. In IV, you could break off specific pieces, but the whole of armor breaks this time so, again, no second or third armor break.
See this video (and description) for more info about equipment destruction in the game.