Fragmentation (weaponry)

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Grooved body of a Second World War-era U.S. Mk 2 grenade. The grooves covering the exterior of the grenade are used to aid in the gripping of the grenade when throwing. MkII 07.JPG
Grooved body of a Second World War-era U.S. Mk 2 grenade. The grooves covering the exterior of the grenade are used to aid in the gripping of the grenade when throwing.
Diagram of S-mine in the delivery of steel ball fragments Bouncing-mine.svg
Diagram of S-mine in the delivery of steel ball fragments

Fragmentation is the process by which the casing of a projectile from a bomb, barrel bomb, land mine, IED, artillery, mortar, tank gun, or autocannon shell, rocket, missile, grenade, etc. is shattered by the detonation of the explosive filler.

Contents

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 referred to as "shrapnel" by non-military media sources. [1] [2]

History

An illustration of a fragmentation bomb from the 14th century Ming Dynasty text Huolongjing. The black dots represent iron pellets. Ming Dynasty fragmentation bomb.jpg
An illustration of a fragmentation bomb from the 14th century Ming Dynasty text Huolongjing. The black dots represent iron pellets.

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 fragments are capable of piercing the skin and blinding enemy soldiers. [3]

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.

Huolongjing , Part 1 Chapter 2 [3]

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. [4]

Difference between fragmentation and shrapnel shells

Animation of a bursting
shrapnel shell Shrapnel shell.gif
Animation of a bursting
shrapnel shell

The term "shrapnel" is commonly, although incorrectly from a technical standpoint, used to refer to fragments produced by any explosive weapon. However, the shrapnel shell, named for Major General Henry Shrapnel of the British Royal Artillery, predates the modern high-explosive shell and operates via an entirely different process. [1]

A shrapnel shell consists of a shell casing filled with steel or lead balls suspended in a resin matrix, with a small explosive charge at the base of the shell. When the projectile is fired, it travels a pre-set distance along a ballistic trajectory, then the fuse ignites a relatively weak secondary charge (often black powder or cordite) in the base of the shell. This charge fractures the matrix holding the balls in place and expels the nose of the shell to open a path for the balls, which are then propelled out of the front of the shell without rupturing the casing (which falls to earth harmlessly and can be retrieved and reused). [5] These balls continue onward to the target, spreading out in a cone-shaped pattern at ground level, with most of their energy coming from the original velocity of the shell itself rather than the lesser force of the secondary charge that freed them from the shell. Since the cone of impact is relatively small, no more than 10 to 15 times the diameter of the shell, true shrapnel shells needed to be carefully sighted and judiciously used in order to maximize their impact on the enemy.

In contrast, a high-explosive shell contains a relatively large and energetic secondary charge of high explosive (known as a burster charge) which, when ignited by the fuse, produces a powerful supersonic shock wave that shatters the entire shell casing into many fragments that fly in all directions. [6] The use of high explosives with a fragmenting case improves efficiency as well as propelling a larger number of fragments at a higher velocity over a much wider area (40-60 times the diameter of the shell), giving high-explosive shells a vastly superior battlefield lethality that was largely impossible before the Industrial Era. World War I was the first major conflict in which HE shells were the dominant form of artillery; the failure to adapt infantry tactics to the massive increase in lethality they produced was a major element in producing the ghastly subterranean stalemate conditions of trench warfare, in which neither side could risk movement above ground without the guarantee of instant casualties from the constant, indiscriminate hail of HE shell fragments.

One easy comparison between fragmenting HE and shrapnel shells would be to imagine a shell of each type standing stationary and base-first on the ground; a high-explosive shell would be equally lethal if detonated in this state vs. detonating on impact after being fired, whereas a shrapnel shell would ineffectually fire its contents only a few feet into the air in a cone-shaped pattern (while the casing itself remained intact). [1] However, the reduced area of effect of shrapnel shells can be exploited, such as in the creeping barrage tactics of World War I, where shrapnel shells were able to be used much closer to friendly infantry than HE shells could.

Related Research Articles

Shrapnel shell Anti personnel, carries shot near target and ejects it

Shrapnel shells were anti-personnel artillery munitions which carried many individual bullets close to the target and then ejected them to allow them to continue along the shell's trajectory and strike the target individually. They relied almost entirely on the shell's velocity for their lethality. The munition has been obsolete since the end of World War I for anti-personnel use, when it was superseded by high-explosive shells for that role. The functioning and principles behind Shrapnel shells are fundamentally different from high-explosive shell fragmentation. Shrapnel is named after Major-General Henry Shrapnel (1761–1842), a British artillery officer, whose experiments, initially conducted on his own time and at his own expense, culminated in the design and development of a new type of artillery shell.

M18 Claymore mine American directional anti-personnel mine

The M18A1 Claymore is a directional anti-personnel mine developed for the United States Armed Forces. Its inventor, Norman MacLeod, named the mine after a large medieval Scottish sword. Unlike a conventional land mine, the Claymore is command-detonated and directional, meaning it is fired by remote-control and shoots a pattern of metal balls into the kill zone like a shotgun. The Claymore can also be victim-activated by booby-trapping it with a tripwire firing system for use in area denial operations.

Bomb explosive weapon that uses exothermic reaction

A bomb is an explosive weapon that uses the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy. Detonations inflict damage principally through ground- and atmosphere-transmitted mechanical stress, the impact and penetration of pressure-driven projectiles, pressure damage, and explosion-generated effects. Bombs have been utilized since the 11th century starting in East Asia.

Brisance is the shattering capability of a high explosive, determined mainly by its detonation pressure. The term can be traced from the French verb "briser" ultimately derived from the Celtic word "brissim". Brisance is of practical importance for determining the effectiveness of an explosion in fragmenting shells, bomb casings, grenades, structures, and the like. The sand crush test and Trauzl lead block test are commonly used to determine the relative brisance in comparison to TNT.

Pipe bomb

A pipe bomb is an improvised explosive device which uses a tightly sealed section of pipe filled with an explosive material. The containment provided by the pipe means that simple low explosives can be used to produce a relatively large explosion due to the containment causing increased pressure, and the fragmentation of the pipe itself creates potentially lethal shrapnel.

High-explosive anti-tank Can penetrate thick armor

High-explosive anti-tank (HEAT) is a type of shaped charge explosive that uses the Munroe effect to penetrate heavy armor. The warhead functions by having an explosive charge collapse a metal liner inside the warhead into a high-velocity superplastic jet; this superplastic jet is capable of penetrating armor steel to a depth of seven or more times the diameter of the charge. The jet's effect is purely kinetic in nature; the round has no explosive effect on the target.

Shell (projectile)

A shell is a payload-carrying projectile that, as opposed to a solid round shot, contains an explosive, incendiary or other chemical fillings, though modern usage sometimes includes large solid kinetic projectiles properly termed shot. Solid shot may contain a pyrotechnic compound if a tracer or spotting charge is used. Originally it was called a bombshell, but "shell" has come to be unambiguous in a military context.

Air burst Detonation of an explosive above a target for increased pressure wave damage

An air burst or airburst is the detonation of an explosive device such as an anti-personnel artillery shell or a nuclear weapon in the air instead of on contact with the ground or target. The principal military advantage of an air burst over a ground burst is that the energy from the explosion is distributed more evenly over a wider area; however, the peak energy is lower at ground zero.

Anti-personnel mine Form of land mine designed for use against humans

Anti-personnel mines are a form of mine designed for use against humans, as opposed to anti-tank mines, which are designed for use against vehicles. Anti-personnel mines may be classified into blast mines or fragmentation mines, the latter may or may not be a bounding mine.

F1 grenade (Australia) Type of Time-fused grenade

The F1 fragmentation hand grenade is manufactured by Thales Australia exclusively for the Australian Defence Force as a primary defensive Anti-personnel grenade.

Ammunition Weapon loads: projectiles, bombs, missiles

Ammunition is the material fired, scattered, dropped or detonated from any weapon. Ammunition is both expendable weapons and the component parts of other weapons that create the effect on a target. Nearly all mechanical weapons require some form of ammunition to operate.

In military munitions, a fuze is the part of the device that initiates function. In some applications, such as torpedoes, a fuze may be identified by function as the exploder. The relative complexity of even the earliest fuze designs can be seen in cutaway diagrams.

Grenade Small bomb that can be thrown by hand

A grenade is an explosive weapon typically thrown by hand, but can also refer to an shell shot out by a rifles or a grenade launcher. A modern hand grenade generally consists of an explosive charge ("filler"), a detonator mechanism, an internal striker to trigger the detonator, and a safety lever secured by a linchpin. The user pulls the safety pin before throwing, and once thrown the safety lever gets released, allowing the striker to trigger a primer that ignites a fuze, which burns down to the detonator and explodes the main charge.

An artillery fuze or fuse is the type of munition fuze used with artillery munitions, typically projectiles fired by guns, howitzers and mortars. A fuze is a device that initiates an explosive function in a munition, most commonly causing it to detonate or release its contents, when its activation conditions are met. This action typically occurs a preset time after firing, or on physical contact with or detected proximity to the ground, a structure or other target. Fuze, a variant of fuse, is the official NATO spelling.

A contact fuze, impact fuze, percussion fuze or direct-action (D.A.) fuze (UK) is the fuze that is placed in the nose of a bomb or shell so that it will detonate on contact with a hard surface.

SB 1000 Type of Luftmine

The SB 1000 (Spezialbombe) was a luftmine or aerial mine in English used by the Luftwaffe during World War II.

SB 2500 Type of Luftmine

The SB 2500 (Spezialbombe) was a luftmine or aerial mine in English used by the Luftwaffe during World War II.

SD 50 (bomb) Type of Fragmentation bomb

The SD 50 or thick walled explosive bomb in English was a fragmentation bomb used by the Luftwaffe during World War II.

SD 70 (bomb) Type of Fragmentation bomb

The SD 70 or thick walled explosive bomb in English was a fragmentation bomb used by the Luftwaffe during World War II.

SD 250 Type of Fragmentation bomb

The SD 250 or thick walled explosive bomb in English was a fragmentation bomb used by the Luftwaffe during World War II.

References

  1. 1 2 3 "What is the difference between artillery shrapnel and shell fragments?". Combat Forces Journal. March 1952. Archived from the original on 10 February 2017.
  2. Archived 1 February 2014 at the Wayback Machine Examples of use of "shrapnel" for casing fragments
  3. 1 2 Joseph Needham (1986). Military Technology: The Gunpowder Epic. Cambridge University Press. pp. 180–181. ISBN   978-0-521-30358-3.
  4. The New Weapons of the World Encyclopedia: An International Encyclopedia from 5000 B.C. to the 21st Century. St. Martin's Press. 21 August 2007. p. 88. ISBN   978-0-312-36832-6.
  5. U.S. War Department Technical Manual 9-1900 ‘'Ammunition, General'’. 18 June 1945. p. 106. Available: http://90thidpg.us/Reference/Manuals/index.html
  6. What forensic conclusions can be drawn from the analysis of shell fragments: https://www.tandfonline.com/doi/pdf/10.1179/1574077313Z.00000000029?needAccess=true