Rivet

Rivets/Studs
These are parts used for joining plate materials via plastic deformation. The head has a pan shape that is inserted into a hole drilling in stacked sheet materials up to the trunk (shaft, mandrel), then fixed by distorting the other side (crushing, opening).
These are also known as studs.
Various head shapes including circle, plate, round plate, flat, pan, and other types exist, as do various materials.
Types that can be tightened from one side, such as by screwing or hammering the tip, are also available.