R. Meyer J. Köhler A. Homburg Explosives

281 Shaped Charges
ner can pierce steel sheets eight times as thick as the diameter of the
charge.
Liners for shaped charges are made of inert material, usually a metal.
The lining acts as an energy carrier, since the energy of the explosive
charge is concentrated on a small cross-section of the target.
The detonation of the explosive charge causes the lining material to
collapse and to converge in the axis of symmetry of the charge. During
this process the colliding metal mass separates into a large mass
portion moving slowly and a smaller mass portion moving forward at
very high speed. Only the fast moving portion with its high kinetic
energy produces the perforation effect in the target: It forms a jet of
very small diameter and correspondingly high density of energy. The
slow moving portion is left as a conglomerated molten slug after
detonation.
The main parameters to characterise a lined shaped charge are the
detonation velocity, the density of the explosive, the geometry of the
detonation wave, the shape of the lining, the lining material and its wall
thickness.
Cutting charge
A plane-symmetrical shaped charge (cutting charge) is an explosive
charge with a hollow space, which acts longitudinally in the plane of
symmetry (“roof-shaped” charges).
Plane charge
In a plane charge the opening angle of the conical liner is larger than
100°. When the explosive is detonated, the lining no longer converges
into a jet in the axis of symmetry, so that no jet or slug can be formed
out of the collapse point; rather, the lining is turned inside out. The
resulting sting is much thicker and much shorter with a weaker perforating
power, but a larger perforation diameter than that made by a
shaped charge.
Projectile-forming charge; self-forging fragment;
EFP (explosively formed projectile)
In a projectile-forming charge, the geometry of the lining is such that
all its elements have approximately the same velocity. The strength of
the material is chosen so that it can easily absorb the residual differences
in the velocities. In this way a projectile with a greater kinetic
energy is obtained, which consist, roughly speaking, of the entire
mass of the lining, and which can also be employed against distant
targets.
The shaped-charge effect was first described in 1883. Shortly before
the Second World War, Thomanek found that the piercing power of the