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Polymers in Special Uses
Published in Manas Chanda, Plastics Technology Handbook, 2017
The last-named polymer exhibits liquid crystalline phase in sulfuric acid solution. The solution is extruded to form a fiber, resulting in further alignment of the molecules. The product, once the sulfuric acid is removed, is a fiber with a more uniform alignment than could be obtained simply by drawing and thus has much better mechanical properties. The tensile strength of Kevlar (see Table 4.17), for example, is considerable higher than that of steel, whereas its density is much lower. Although most Kevlar produced is used in tie cord, the polymer also finds use in specialty clothing. Light-weight bulletproof vests are made containing up to 18 layers of woven Kevlar cloth.
History of Protection Armor
Published in Magdi El Messiry, Protective Armor Engineering Design, 2019
The main function of the body armor is to absorb the impact energy of bullet to reduce or stop the bullet from penetration into the body. The modern bulletproof vest is formed from several layers of fabric or laminated fibers or both capable to protect the warriors from small caliber bullet gun projectile and fragments of a grenade.
UHMWPE textiles and composites
Published in Textile Progress, 2022
Ashraf Nawaz Khan, Mohit Gupta, Puneet Mahajan, Apurba Das, R. Alagirusamy
Around the world, body armour actively saves human life against potential threats. The usage of the body armour includes special forces and police on their daily beat patrols. The ballistic vests are employed by the armed forces for their personal protection and operational enhancement. Therefore, it becomes extremely crucial to understand the working of armour technology developed for providing that protection. The main purpose of the bulletproof vest is to provide ballistic protection to protect vital organs such as the heart, lungs, liver, kidneys, spleen and backbone. This protection can be extended to the thighs, lower abdominal region as well as the arms. A ballistic material must have very high strength to bear the impact load of a projectile. The energy dissipation characteristics of ballistic material largely depend on the sonic velocity of the fibre and the construction of the material. The sonic velocity is related to the elastic modulus of the fibre as expressed by Equation (5). A higher elastic modulus results in faster and longer-moving impact energy waves due to higher sonic velocity. where C = sonic velocity, E = elastic modulus, and ρ = fibre density.
Study on chest injury and bulletproof vest protection under the combined action of blast wave and fragments
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2022
Zhihua Cai, Zhi Wang, Lijun Chang, Xingyuan Huang, Hui Zhao
As shown in Figure 1b, for the fragment material of the IED, the STEEL4340 model in Autodyn material library was adopted. Kevlar is an ideal material for bulletproof vest because of its impact resistance, high strength and low weight. In this paper, KEVLAR EPX model in Autodyn material library was used for bulletproof plate material, and Von Mises strength model was selected (Cai et al. 2016). Viscoelastic materials were used in muscle, heart and lung, and elastic materials were used in other organs. The material parameters of chest organs are shown in Table 3.