What is the name of the battering ram in The Lord of the Rings?
The name of the great battering ram in the shape of a wolf used against the gates of Minas Tirith was named Grond, presumably after Morgoth's hammer from the First Age.
The band Rammstein took its name from the Ramstein Air Base where a tragedy involving planes occured during a flight show. The word "Rammstein" doesn't really exist, but it could be explained as a different version of the "Rammbock" ("battering ram"), which would make it a "battering ram made of stone".
A scaling tower was used in ancient wars to allow soldiers to reach the top of an enemies' town or fortress walls. If a battering ram is attached to it, then scaling the walls over an entrance to a fortress or city plus using the battering ram to break open the forts doors can be accomplished. This type of war "machines" were used into the Middle Ages.
As a device intended to knock down a sealed door of some kind, a battering ram is indeed a simple machine; or, at least, it can be. For, while sophisticated battering rams have been created and utilized, the trunk of a tree can serve just as well, when and where the gate or gateway to be rammed open is appropriately sized.