| Summary: | 碩士 === 國防大學理工學院 === 兵器系統工程碩士班 === 99 === In the process of ballistic protection, the general sources of threat in addition to bombs, bomb fragments, most of which come from small arms ammunitions. In order to increase the protective properties of composite fiber materials, we have to consider the impact of different types of projectile (bullet shape, mass, etc.) in addition to considering warhead material, impact speed and incident angles.
This paper evaluates the ballistic performance of Kevlar laminated fabrics when impacted by three different projectile shapes： flat head, ogival head and conical head. All projectiles have a diameter of 7.62 mm and a mass of 5 g. The impact velocities were varied up to a maximum of 330 m/s. This study used the ANSYS and LS-DYNA finite element software to precede the simulation. The results from simulation were then compared with the experimental results to verify the correctness of the simulation.
From the experiments and numerical simulation results, it was shown that the ballistic limit velocity (V50) and the energy absorption of Kevlar fabrics increase with the increase of number of layers. Kevlar plain woven fabrics subjected to ogival projectile had higher V50 values, followed by conical projectile, and then flat projectile. In this research, it is shown that the resistance to tensile failure of Kevlar fabric is superior to shear failure.
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