Penetration ballistic impact tests

The ballistic performance of these materials was determined by a standard projectile impact test. This performance is characterized by the average impact velocity at which the projectile barely penetrates the test specimen. Accordingly the higher the characteristic velocity, the better is the ballistic performance or the ballistic impact resistance of the specimen. The data are presented in arbitrary units. 

A typical helmet is expected to be between 5 and 10 mm thick, dependent on both material type and applicatioa The shell thickness is normally determined experimentally by the penetration test. The shell canbe made of either an injection-moulded thermoplastic or a pressure-moulded resin system, reinforced with ballistic resistance fabrics/fibres (Mills, 1996). Energy is absorbed when the helmet is impacted, with the shell bending and deformation of the underlying foam. The amount of the impact energy absorbed by the foam depends on ... 

Kohlman and Petrie (1995) produced blends of 5 %, 10 % and 20 % by weight of polysulfone in polycarbonate by melt blending. The average impact strength and the percent of ductile failures decreased with increasing amount of polysulfone. The ballistic testing results that were reported showed a linear relationship exists between the percent of polysulfone in the blend and the critical velocity for complete penetration. 

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