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The insufficient recognition of injuries by the BB-gun (regarded as toys for children) has led to its increasing misuse without permission, which has caused many public safety issues. Aiming to enhance the understanding of the injuries by the BB-gun, the experimental and numerical study of BB-Gun pellet penetrating "cowhide + gelatine" composite target was comprehensively carried out. It was confirmed from the experiment that BB-Gun is capable of inflicting severe or fatal wounds to important organs, and perforating the skin or not could be employed to evaluate the safety of BB-guns. Moreover, three forms of ballistic limit (including: velocity, kinetic energy and specific kinetic energy) of typical BB were calculated and analyzed by reasonably validated numerical simulation method. Additionally, a formulation was acquired by dimensional analysis based on the simulation results and was verified to accurately predict the ballistic limit velocity of BB with different mechanical properties. The method may help to improve the understanding on the minimal velocity needed to perforate skin and may be advised as the determination of the safety of BB-gun. [ABSTRACT FROM AUTHOR]

Plastilina is often used as a ballistic witness material (BWM) behind the armour to evaluate the backface signature (BFS). Indeed, it is cheap, reusable and it keeps its deformation after being impacted. Moreover, while it aims at evaluating the performance of ballistic protections when no perforation occurs, it can be subjected to a very wide range of strain/shear rates during a ballistic impact. Therefore, there is a need to improve the knowledge about the mechanical/rheological response of such a material. This paper proposes both experimental and modelling approaches to determine the response of the specific ballistic plastilina red Weible® over a wide range of shear/strain rate. A capillary rheometry analysis with control of temperature was performed up to 8.104 s-1. The corrections of Rabinowitsch and Bagley were applied and an attempt of the analysis of Mooney was considered. From the rheology of plasticine, a two-parameters based power-law constitutive equation was deduced. An experimental drop test was carried out using a specific standard setup. A high-speed camera was used for measuring the penetration depth of a steel ball into the plastilina. A numerical simulation of the drop test was performed by taking into account the mechanical properties of the plastilina. A good correlation was observed between the experimental and numerical results in terms of indentation depth evolution. [ABSTRACT FROM AUTHOR]