The aim of the study is to identify the relevant aspects of numerical analysis of impact of projectiles with soft cores into a package composed of thin flexible plies located on the plastic backing. In order to illustrate the problem, normal impact of 7.62 mm TT projectile into an unclamped package comprising 36 plies of Dyneema SB71 supported on the plastic backing was selected. The problem was solved with the use of the finite element method (FEM) with the explicit integration scheme (central difference method) of motion equations in the matrix form. Based on the conducted numerical computations, it was revealed that obtaining the extreme deformations of a projectile soft core and the backing material in Lagrangian description requires employment of adaptive methods. The proposed R-adaptive method performs its role but must be used carefully due to the mass loss which may appear during calculations.
Materials and their development process are highly dependent on proper experimental testing under wide range of loading within which high-strain rate conditions play a very significant role. For such dynamic loading Split Hopkinson Pressure Bar (SHPB) is widely used for investigating the dynamic behavior of various materials. The presented paper is focused on the SHPB impulse measurement process using experimental and numerical methods. One of the main problems occurring during tests are oscillations recorded by the strain gauges which adversely affect results. Thus, it is desired to obtain the peak shape in the incident bar of SHPB as “smooth” as possible without any distortions. Such impulse characteristics can be achieved using several shaping techniques, e.g. by placing a special shaper between two bars, which in fact was performed by the authors experimentally and subsequently was validated using computational methods.