The chances are the shaft in question is most likely made of aluminium. The "tube"of the shaft will carry "noise" of the drive train. The covering is there to help limit the noise and vibration. It is more for dampening noise than a structural covering.
Wind motion is converted to propellor motion. Propellor motion is turned into shaft motion. Shaft motion is geared down to optimal generator rotational speed (if not handled by propellor trim). Generator makes electrical power. Inverter synchronizes with power grid, and pushes electrical power into the grid.
drive shaft
The stern tube in marine engineering allows the propellor shaft to penetrate the hull of a ship and prevent the ingress of water. It also acts as a bearing and lubricates that part of the shaft.
automobile propeller shaft material
The shaft in lacrosse is the stick part. The butt is the rubber stopper on the end of the stick. The head is the plastic part which has the pocket. The shaft is the part of the stick where you hold it.
The universal joint is used to transfer drive (power) from one shaft to another when they are inclined (non collinear) to each other.
Differential, many times called the rear-end or third member.
Move the steering shaft. There is one bolt under the plastic cover. This is the pinch bolt .Remove it and slide shaft towards firewall ,move shaft out of the way ,replace plug,re-install shaft,bolt and plastic cover.
The gripper shaft is a rubber, leather, or textured metal part between the point and the fletching{ feathers or plastic fins], on the body of the dart.
Ball, roller, and needle bearings are made of various hard steel alloys. Bushings are coated with either a soft alloy called Babbitt metal or a plastic over the contact surface. This coating slowly wears away, protecting the shaft and journal from direct contact.
One type of ultrasonic machining I am familiar with is called "sonic welding". It is used for things like attaching the white plastic button to the metal shaft of a guitar tuner. The button is placed on the shaft, high speed sound waves are directed at the assembly, causing the plastic to melt around the surface of the shaft and secure it there.
It should be on the shaft of the sliding door handle (the shaft that goes through the door). Remove the plastic cover on the inside and there will be a single philips head screw to remove; do this and the shaft should come out. The code will be stamped on it.