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1 Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

1 2011

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Numerical Simulations of Penetration of 9 mm Parabellum Bullet into Kevlar Layers : Erosion Selection in Autodyn Program

Wiśniewski A., Pacek D.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

2011

Vol. 2, Nr 3 (5)

11-20

A numerical model was performed of penetration of 9 mm Parabellum bullet into Kevlar layers, with the use of the AUTODYN software program. Simulations were conducted with a bullet modelled by means of the Smooth Particle Hydrodynamicsmethod (SPH) and with an armour coded by a Lagrange grid. The simulations were performed for 20 layers of Kevlar (one layer: thickness - 0.3 mm, surface density - 220 g/cm²) and for impact velocity of 350 m/s. The comparison included the mean velocity of the bullet (which takes into account the velocities of particles that separated from the part of the bullet penetrating the armour) and the velocities at gauge points established near the axis of symmetry of the bullet. The gauge point representative for velocity of the bullet was indicated. With regard to excessively large deformations of the grid, that caused interruption of the initial simulation, the criteria of erosion (cells removal) were introduced. From effective strains available in the AUTODYN software, the effective instantaneous geometric strain was selected. Influence of the erosion strain (value of strain for which cells are removed) onto the mass of removed cells and the residual velocity of the bullet were investigated. Simulations with neglect and respect to mass of removed cells in further calculations were performed. The erosion criteria for which further simulations should be conducted were indicated.