Lightweight body armor

Kevlar 29 and versions thereof (K 129 and Kl j.) are also used extensively in lightweight body armor as well as composite liners (with vinylester, polyester or epoxy as the matrix). A quick look at the properties of different Kevlar aramid fibers in Table 4.2 shows why K29 is better than K49 for lightweight body armor applications. K29 has a higher strain to failure than K49. That means that the total work of fracture, i.e. the area under the stress-strain curve, is larger for K29 than K49. Hence, the energy absorbed in the fracture process is higher for K29... 

B. Technical Info An excellent source of Kevlar technical information is a 1976 Government sponsored report on Lightweight Body Armor. The 113 page report contains many charts and illustrations. 

Spider-web silk is ca. five times stronger than steel by weight, and almost as elastic as nylon. Fibers comprised of the synthetic silk were demonstrated to be stronger than Kevlar, and may be useful for biomedical applications such as artificial tendons and ligaments and surgery sutures, as well as lightweight body armor for military applications. 

KEVLAR DuPont Kevlar aramid fibers are lightweight and extraordinarily strong, with five times the strength of steel on an equal-weight basis. Best known for its use in ballistic and stab-resistant body armor, Kevlar brand aramid fibers are also used in cut-resistant and heat-resistant protective gloves and sleeves. Woven and knit gloves made solely from Kevlar fibers do not provide chemical protection. 

Spider silk (see Fig. 20.23 in the text) is one of the strongest known fibers. Artificial spider silk (see Fig 20.24) is being used to make lightweight, thin, and flexible body armor. 

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