###### Abstract
Many studies have been performed on the influence of projectile shapes on the BAD cloud. [PERSON] et al. [15] compared the debris cloud of projectiles with three \(L/D\)s, i.e., 0.058 (disk), 1.00 (right cylinder), and 3.00 (long rod). BAD cloud images of long-rod and cylindrical projectiles (\(L/D=1\)), which were in the process of penetrating a steel target, were taken by [PERSON] et al. [16]: The radial scattering range of a short cylindrical projectile is large. In contrast to EFP, the projectiles in these studies were titer regular or the \(L/D\) could be precisely controlled. In addition, the spatial distribution of BAD is closely related to the damaging effect of the internal components of the armored vehicle [17; 18]. Many studies evaluated the relationship between BAD mass and velocity and the scattering angle for long-rod projectiles [19; 20; 21]. However, the ultimate goal of studying the scattering characteristics of secondary fragments behind the target is to analyze the damaging ability to the internal crew and to instruments within the armored target; the damaging elemental energy is an effective criterion with which to measure the damaging effect. Therefore, it is necessary to investigate the spatial energy distribution of BAD. There are currently limited methods avilable to measure the kinetic energy distribution of the BAD cloud; only numerical simulations are available. [PERSON] et al. [22] obtained the specific kinetic energy of the BAD cloud through numerical simulations and then obtained the function of the sum of the specific kinetic energies of particles per unit annular area. [PERSON] et al. [23] obtained the energy distribution of dangerous fragments with respect to the spatial scattering angle. In an experimental study, [PERSON] [24] weighed the BAD collected by the foam layer of a witness package and calculated the energy of the fragments using X-ray technology. However, the author did not present the results of the BAD energy in detail. Based on the number of perforations in witness targets with 3-5 layers, [PERSON] et al. [25] found that the increase in the diameter of the rod-type projectile significantly increased the penetration ability/energy of the fragments. [PERSON] et al. [26] evaluated the kinetic energy and chemical energy behind the target according to the perforated area of the multi-layered spaced aluminum witness plate. [PERSON] et al. [27] used rubber materials to recover fragments and employed X-ray tomography to obtain the energy distribution of the tungsten fragments. The results showed that the number of high-energy fragments decreased with increasing impact velocity. These studies mainly focused on the energy of BAD based on space debris, shaped charge jets, or long-rod projectiles; the shape and velocity are much different than that of EFP. Therefore, it is necessary to analyze the energy distribution and the potential striking area of the BAD resulting from EFP penetration. [PERSON] et al. [28] obtained the relationship between the cumulative lethality of the BAD and the scattering angle. [PERSON] et al. [17] found that the kinetic energy of the BAD decreased exponentially with increasing scattering angle, but they did not distinguish between EFP fragments and target fragments. [PERSON] et al. [29] reported that the BAD with large kinetic energy was mainly generated by EFP and located far from the target. However, the smoothed-particle hydrodynamics (SPH) algorithm has some limitations, such as unstable tension and difficulties in applying physical boundaries; thus, the results from the simulation may be different from the actual results. These studies all used numerical simulation methods to study the energy distribution of the BAD from EFP penetrating target and did not involve spatial energy distributions, discrimination of EFP and target fragments in the experiment. Due to the high degree of randomness in BAD scattering, it is necessary to use the experimental method of [PERSON] et al.