# Numerical Analysis and Experimental Test for the Development of a Small Shaped Charge
## 5 Conclusions  
The main purpose of the paper was to test and analyze the effectiveness of small-shaped charges in terms of their ability to penetrate a steel block. The conducted experimental tests allowed us to determine the real ability to penetrate a steel target with a shaped charge at a variable value of its distance from the target. On the basis of the experimental test, the breakthrough values of 110 and 220 mm were obtained for two variants of the charge standoff from the target, determined by the proprietary solution in the form of a spacer sleeve. As a result of the numerical analyses carried out, the process of validation of the numerical model in the axisymmetric approach was conducted using the Multi-Material Arbitrary Lagrangian-Eulerian (MM-ALE) formulation method. The performed numerical model made it possible to regulate the distance of the charge from the target in accordance with the actual conditions, while maintaining all dimensions of the components of the load, i.e., casing, cumulative insert and the explosive used there. The obtained results of the penetration depth obtained by means of numerical analyses and experimental tests were characterized by a difference at the level of 4-8%, which made it possible to adopt the method used as effective for modeling the cumulative charge. After a successful validation process, further numerical analyses were carried out for the remaining variants of the load positioning in relation to the target, using the distance adjustment system of the sleeve. The method of formation of the cumulative flux and  
Figure 6: View of the shaped charge jet with the marked map of the resultant velocity at the moment of contact with the target: (**a**) 7.5 mm standoff, (**b**) 20 mm standoff, (**c**) 32.5 mm standoff, (**d**) 45 mm standoff, (**e**) 57.5 mm standoff and (**f**) 70 mm standoff. the ability to break through another material in terms of the distance between them were checked via numerical analyses. A graph of the change of the penetration capacity of a shaped charge jet in a steel block depending on the distance between it and the target was developed. The exponential trend line shown in Figure 3 illustrates this relationship. Another phenomenon that was verified by numerical analysis was the velocity of the jet reached at the moment when the top of it contacts the target. Based on the conducted analyses, the results for all tested variants of the retraction were collected, as shown in Table 9.  
To sum up, the assumption of this paper was to carry out the modeling and validation process of the shaped charge initiation and propagation process in interaction with a steel target. The method of modeling the phenomenon of this problem in the axisymmetric approach was used, which faithfully reflects the conditions of real experimental research. The obtained results constitute the basis for further numerical research based on a correctly functioning and validated numerical model. Subsequent papers will focus on analyzing the effectiveness of a small-shaped charge jet penetration with other types of materials. Conceptualization, P.M., G.S. and K.P. ; methodology, P.M., G.S. and K.P. ; software, P.M. and G.S. ; validation, P.M. and G.S. ; formal analysis, P.M., G.S. and K.P. ; investigation, P.M., G.S. and K.P. ; resources, P.M., G.S. and K.P. ; data curation, P.M., G.S. and K.P. ; writing--original draft preparation, P.M., G.S. and K.P. ; writing--review and editing, P.M., G.S. and K.P. ; visualization, P.M., G.S. and K.P. ; supervision, P.M., G.S. and K.P. ; project administration, G.S. ; funding acquisition, G.S. All authors have read and agreed to the published version of the manuscript. The article was written as part of the implementation of the university research grant supported by the Military University of Technology (No. UGB 22-746/2020). Not applicable. Not applicable  
Special thanks for organizing and conducting experimental studies of the impact of the shaped charge on the steel block to [PERSON] from Military University of Technology.