Fragmentation (weaponry)

Fragmentation is the process by which the casing of an artillery shell, bomb, grenade, etc is shattered by the detonating high explosive filling. The correct technical terminology for these casing pieces is fragments, shortened to frags, although shards or splinters can be used for non-preformed fragments. The fragments, as mentioned previously, can also be preformed and of various shapes (spheres, cubes, etc) and sizes. Preformed fragments are normally held rigidly within some form of matrix, or body until the HE filling is detonated. The resulting high velocity fragments produced by either method are the main lethality mechanisms of these weapons. The word "shrapnel" is often used to describe these fragments, the word "shrapnel" originally referred to a specific type of shell, the "shrapnel shell", which doesn't rely on a high explosive to shatter the casing. A World War I era shrapnel shell uses a small (black) powder charge in the base of the shell to expel the lead or iron shot at a relatively low velocity, 200 m/s (700 ft/s). The expulsion, at a predetermined time and height above the target area, is controlled by a time fuse. Due the low velocity of the shot, unlike the fragments produced by a detonating HE munition, it is only really effective against human targets, not material or armor.