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» Personal Loan No Credit Check, Online Economics » Explosive » Topics begins with H » Hollow charge


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The hollow charge is a special arrangement of explosive explosive, (often on Nitropenta or Hexogen/Oktogenbasis) around cone or halfspherical metal insert, which is particularly suitable for piercing armoring. It is used accordingly in tank ammunition, antitank weapons and Bomblets.

Function mode

A conical metal insert with opening arranged forward is surrounded with as explosive an explosive as possible. The fuze sits at the back of the charge. If the charge is ignited, then - outgoing from the point of the metal cone - a prick forms followed from coldly deformed metal, which penetrates the goal with very high speed, from a slower "tappet", which forms the bulk. Against the opinion the material does not reach the melting point. This concerns a pure deformation at low temperatures with very high pressures. The observation does not oppose that from practice that the use of hollows charge accompanies frequently with fire and fires. This is a secondary effect by pressure-liquefied goal material, which distributes itself and burns at air pyrophor. Also steel can burn under these extreme circumstances.

The insert (English: Liner) is manufactured made of a well ductile metal with as high a density as possible. Copper offers these characteristics and is therefore gladly used. Still better results could gold be obtained also, what in the necessary quantity however is too expensive. The Russian 3BK-21B uses a lining from uranium. Uranium is strengthened pyrophor and by fire effect the damage behind armoring. With the TOW2B is used tantalum. Tantalum is likewise a metal with high density and pyrophoren characteristics.

The production of this metal jet becomes possible by a geometrical-dynamic peculiarity with detonations of hollows charge, in accordance with that the detonation front as shock wave with supersonic speed spreads and the metal insert quasi in a focus - more exact: on an axle - to the reciprocal effect one brings (design B). "Spindles" separate particles mentioned from the developed prick individual, which affect highly energetic then gradually the goal. Thus a channel of small piping develops with sufficient precision of the arrangement. The explosion gases flowing with subsonic speed are irrelevant for the effect.

The speed of the prick depends on the explosiveness of the explosive and on the cone angle of the metal insert. Ever pointedly, the more highly the speed of the prick, but the smaller its mass in relation to the tappet, so that in practice a compromise is necessary. After Pokrowski (see bibliography) on laboratory conditions speeds were reached around 100 km/s, what does not have a meaning however because of the expenditure (among other things expansion in vacuum chambers) for commercial and military purposes.

Since the detonation front would have alone no large penetration strength, the surface of the hollow charge becomes, as provide described above, with a metal situation. The metal is coldly deformed with the detonation with the pressure and hurled to the longitudinal axis of the cone. There the metal meets one another and forms cumulative Metallstrahl.Die point of this jet moves with very high speed. With military systems this speed is within the range of approximately 7 km/s to 10 km/s. meets this jet on an obstacle, develops an extremely high pressure. With a Strahlgeschwindigkeit around 10 km/s the pressure is in the order of magnitude of 200 GPa (approx. 2 million atmospheres). With this pressure solids behave such as liquids, so that the metal jet penetrates the obstacle after regularities of hydrodynamics like a liquid, which justifies the penetration performance of hollows charge. If a hollow charge pierces armoring a vehicle, like an explosion penetrating the metal jet and fragment of armoring can ignite the fuel or the ammunition and kill the crew. The opening, which such a jet leaves, is substantially smaller than the caliber of the original projectile.

Since the cumulative jet needs something area, in order to develop, hollows charge often possess a long stretched ballistic hood, by which the charge in sufficient distance can be ignited by impact detonation. Because of the high speed of the cumulative jet the airspeed of the projectile equipped with the hollow charge is secondary. Therefore mainly relatively slow is provided, partly reactive (recoilless) projectiles with hollows charge, whereby the weight of the firing equipment can be kept small (e.g. Bazooka or also Panzerfaust). If the projectile is stabilized by means of spin, then penetration performance decreases strongly. The reason is that by the centrifugal energy the jet is expand and from it a larger with lower specific pressure results. For this reason most shaped-charge projectiles are wing-stabilized. Another possibility is to provide the projectile with a spin coat carrying the guide rings. In this the charge carrier on ball bearings is platziert, so that to the charge a much smaller spin will transfer.

Penetration performance of some selected systems with hollow charge:

  • Antitank defense guided missile MILAN (Germany/France): 1000 mm tank steel
  • RPG 7 (Panzerfaust, unguidedly, former Sowjetunion/GUS): 330 mm tank steel
  • Panzerfaust 3 (unguidedly, Germany): 700 mm tank steel
  • APILAS weapon system (guided, France): 710 mm tank steel, 2000 mm reinforced concrete
  • AT-14 Kornet weapon system (guided, Russia): 1200 mm tank steel

Further particularly formed explosive charges

According to the shaped-charge principle also Schneidladungen so mentioned are manufactured, which are V-shaped trained over a certain length not conically, but. With them no punctiform jet, but over the whole length of a kind "thread" made of metal, develops which penetrates through the material. Thus is it possible, e.g. To cut steel girder at relatively small expenditure of explosive over the entire width. Schneidladungen are used primarily with civilian abort projects.

A tarpaulin Wave generator is a conical charge from two different explosives, which is used as contact charge for the production of a flat impact with load tests. The detonation speed of the cone coat (1) (e.g. Composition B, poured, 39 % TNT + 60 % RDX + 1 % wax), v1 = 7980 m/s) is larger than those of the interior cone (2) (e.g. TNT, poured, v2 = 6930 m/s). The opening angle of the cone results out cos (\ alpha) = \ frac {v_2} {v_1}.

Application

The Panzerfaust and the fist cartridge of the German armed forces were recoillessly from a one-way pipe shaped-charge shells which can be fired, which were used in the IITH world war starting from 1942 to the tank fight.

The RPG-7 (Ruchnoy Protivotankoviy Granatomet-7), into the 1950er years developed and for the first time 1961 of Soviet armed forces inserted, is by the shoulder fired, a rocket-powered shaped-charge shell with an employment range to 500 m and a copy achievement of up to 600 mm tank steel. The shells weigh depending upon type between 1,8 kg up to 4.7 kg with calibers of 70 - 105 mm. Newer developments with tandem warhead are effective also against reactive and laminated armor. The RPG-7 is today in Asia, Africa, Latin America, into which Arab countries as well as in east and South-east Europe at armed forces, militias and groups of terror spreads, in many countries also without license is manufactured and is few hundreds a dollar available with international weapon dealers to the unit price of. It is a danger also for most modern tanks and helicopters at ground level.


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