Composite Armor

The published information on ceramic composite armor is neither extensive nor very informative, although it is clear that incorporating a hard, stiff and light-weight 

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Armor. Sihcon carbide is used as a candidate in composite armor protection systems. Its high hardness, compressive strength, and elastic modulus provide superior baUistic capabihty to defeat high velocity projectile threats. In addition, its low specific density makes it suitable for apphcations where weight requirements are critical (11). 

Some Paraplex resin mixts, such as Paraplex P-10 containing Paraplex resin AP-31 and styrene, are used by the Aerojet Engrg Corp, Azusa, Calif as an ingredient of JATO pro pints (see below). The same resin has been used as a constituent of resin-bonded expls (also, see below), while still other Paraplex resins are used to fabricate ceramic-faced composite armor (Ref 4) Refs 1) L.H, Eriksen, Study Stability and Sensitivity Characteristics of Paraplex Propellant ,PATR 1629 (1946) 2) E.T, Benning,... 

This system has been used in development on the lower hull and crew capsule of the US Army s Composite Armored Vehicle and the Northrop-Grumman Advanced Technology Transit Bus. Research is continuing at the US Army Research Laboratory and the University of Delaware Centre for Composite Materials. 

Further improvement in mechanical properties of aramids appears possible since calculations based on perfect alignment and crystalline order predict a theoretical modulus of about 220-245 GPa. The properties of aramid fibers are compared in Table 5. Like carbon, aramid fibers have a negative thermal expansion coefficient in the longitudinal direction. Aramids have high impact resistance, and they have foimd their way into the markets of soft and rigid (composite) armors. 

The functional principle of composite armor materials and the processes occurring during impact of a projectile are shown in Figure 11.5. 

Figure 11.5 Schematic rendering of the impact of a projectile on a ceramic composite armor.

The hardness of boron carbide (carbon hexaboride) is not well defined because it is made as sintered compacts which have variable densities, compositions, and defect densities. It is very hard (up to 4400kg/mm2), and of relatively low density, so it has been used extensively as body-armor (McColm,... 

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