CHARACTERISTICS OF SHRAPNEL FIELDS
Authors: Grigorenko S. , Bordiyan V. , Lyskovchuk V. , Bordiyan P. , Malyshkin O. 
Published: August 2022

The article considers the main characteristics of the shrapnel field or the flow of striking elements per unit area of the affected target, which is at an arbitrary angle relative to the axis of the main ammunition.
The main characteristics of the shrapnel field or the flow of striking elements (SE) – the direction, speed of movement, and its density (the number of SE per unit area intersected). In the general case, the affected target can be at any angle relative to the axis of the main ammunition (MA), so when solving the problem of determining the probability of shrapnel hitting the target, you need to know how many SE flies in this direction.
Consider a typical picture of shrapnel streams that occur during static explosions of high-explosive fragmentation projectile (HEFP). Up to 70% of the mass of the body goes into the circular field formed by the fragments of the walls, about 20% of the fragments fly in the main direction and backwards – about 10%.
Under dynamic conditions, for example, when detonating at a given point in the trajectory, the lateral flow of fragments receives a certain inclination in the direction of the projectile velocity vector. In the case of a ground detonation, when the detonator is installed for instantaneous action, a zone of defeat of ground targets is created in the form of an ellipse, the size of which is limited by the bottomhole interval, at the same time sectors of scattering of fragments of lateral, main and bottom part of the case are allocated.
The ratio of the size (depth and width) of the affected area increases with increasing angle of encounter and for most HEFP is 0.15/ 0.50. At large angles of encounter close to 90° (this is typical for MA type MAA, MHEAA, artillery mines, etc.), the area of affecting is aproaching to circular in shape.
The configuration and size of the affected area are taken into account when assessing the combat effectiveness of the MA, as an example, when calculating the area of the affected area. The main stage of solving this problem is to determine the characteristics of the fragment field for static conditions.
In practice, the effectiveness of splinter effect munition on a particular type of target is characterized by the size (or plane) of the zones of entire and actual damage. The boundary of the zone of continuous defeat is the distance at which the probability of defeat of this type of target is equal to 0.63, and the boundaries of the zone of actual defeat are determined by the level of probability of defeat equal to 0.5.
An important point in assessing combat effectiveness – taking into account the probable nature of the position of the point of detonation of the MA in relation to the target, which is due primarily to trajectory scattering. At ground explosions the trajectory scattering is expressed in the form of an ellipse of scattering, and at air – a measure and the direction of a miss.
To increase the probability of damage, it is necessary to agree on the position of the zones of damage and scattering. In particular, the problem of such coordination arises quite acutely in the covering shelling, ie at small angles of encounter, when the scattering ellipse is strongly elongated in the firing direction (the ratio of lengths of longitudinal and transverse axes of the ellipse reaches 40 се 50), and sectors of the impact zone are perpendicular to the firing direction. In this case, the scattering ellipse and the determined area of damage have a small total area within which the probability of hitting the target is not equal to zero. Thus, at small angles of encounter, it is not so much the area of the determined lesion zone that is important as the configuration of the lesion field and its position relative to the scattering ellipse. It is this circumstance that determines the high efficiency of the MA with axial flows of SE, which primarily includes shrapnel.
The parameters of axial flows of SE (direction, velocity, field density) depend on both the characteristics of the load and the design features of the MA. When blasting an axial warhead with a square MSE block, the SE flow creates a pyramid with a cross-section in the shape of a square, the view of the hole field on the steel shield installed in the path of the SE flow indicates that the transverse configuration of the splinter field generally repeats the MSE block shape.
The distribution of SE in the longitudinal direction of flight can be determined by X-ray survey of the flow in flight. From the presented radiograph it is possible to see that already on small distance the splinter flow becomes echeloned, ie SE of the central zone of the block have higher speeds in comparison with peripheral SE, by the way, the difference in speeds makes 15-20%.
Keywords: shrapnel fields characteristics, striking elements, ammunition.