Blast fragmentation

Fragmentation is the process by which the casing of an artillery shell, bomb, grenade, etc. is shattered by the detonation of the explosive filler.

The correct term for these pieces is "fragmentation" (sometimes shortened to frag); "shards" or "splinters" can be used for non-preformed fragments. Preformed fragments can be of various shapes (spheres, cubes, rods, etc.) and sizes, and are normally held rigidly within some form of matrix or body until the high explosive (HE) filling is detonated. The resulting high-velocity fragments produced by either method are the main lethal mechanisms of these weapons, rather than the heat or overpressure caused by detonation, although offensive grenades are often constructed without a frag matrix.

These casing pieces are often incorrectly referred to as "shrapnel" (particularly by non-military media sources).

The use of fragmentation in bombs dates to the 14th century, and appears in the Ming Dynasty text Huolongjing. The fragmentation bombs were filled with iron pellets and pieces of broken porcelain. Once the bomb explodes, the resulting shrapnel is capable of piercing the skin and blinding enemy soldiers.

For this bomb you take tung oil, yin hsiu, salammoniac, chin chih, scallion juice, and heat them so as to coat a lot of iron pellets and bits of broken porcelain. Then fill in (with a gunpowder core) to a case of cast iron making a fragmentation bomb. When it bursts, it breaks into pieces that wound the skin and break the bones (of enemy soldiers) and blinds their eyes.

The modern fragmentation grenade was developed during the 20th century. The Mills bomb, first adopted in 1915 by the British army, is an early fragmentation grenade used in World War I. The Mk 2 grenade was a fragmentation grenade adopted by the American military based on the Mills bomb, and was in use during World War II.

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