Overview of body armor research
Bulletproof vest research Overview
Abstract: This article discusses the historical changes, classification, evaluation indicators, types of fiber materials used, and development directions of body armor, laying the foundation for the development of body armor that can not only provide protection but also meet comfort and low cost. .
Keywords: bulletproof vest; bulletproof fiber; defense performance; development trend
1 Introduction
Bulletproof vests are personal protective equipment worn to ensure human survival in specific environments. They can absorb and dissipate the kinetic energy of warheads and fragments, prevent penetration, and effectively protect the protected parts of the human body. At present, bulletproof vests mainly refer to bulletproof vests that protect the chest and back to prevent stray bullets and fragments from causing damage to important parts of the human body. With the improvement of the research level of body armor, people are no longer satisfied with only considering the bulletproof performance of body armor. Regardless of whether it is considered from a practical or commercial perspective, lightness and comfort are goals shared by users and manufacturers. Such body armor is increasingly favored by users.
2The development history of body armor
As an important piece of personal protective equipment, body armor has experienced the transition from metal armor protection plates to non-metallic synthetic materials, and has also experienced the development process from simple synthetic materials to composite systems such as synthetic materials, metal armor plates, and ceramic shields. .
The advent of Kevlar fiber in the late 1960s and early 1970s not only represented a new breakthrough in the history of synthetic fiber technology, but also brought a revolutionary leap to body armor. In 1991, the Netherlands invented Twaron fiber and produced ultra-high molecular weight polyethylene body armor that is lighter, has better ballistic resistance, and is more breathable. In 1998, British scientists used polymer fiber materials extracted from liquid crystal to make a new material body armor, and at the same time added an effective anti-static material to create the latest super anti-static body armor. It is not only bulletproof, but can also be worn in places such as aircraft, ships, oil depots, and ammunition depots that are most afraid of static electricity and are most likely to produce static sparks. Even if an explosion occurs accidentally, the bulletproof vest is also very protective.
3 Classification of body armor
Body armor is classified in many ways. According to the level of protection, it is divided into three levels: anti-shrapnel, anti-low-speed bullets, and anti-high-speed bullets; according to the style, it is divided into three types: vest type, jacket type, and pullover type; according to the objects of use, it is divided into ground force personnel bulletproof system anti-fragment vest, The tank crew’s bulletproof system includes anti-fragment bulletproof vests, security bulletproof vests, VIP bulletproof vests, etc.; according to the scope of use, it is divided into two types: police and military; according to the materials used, it is divided into software, hardware and soft-hard composite Three types of bodies.
Hard body armor is also called enhanced body armor. The bulletproof material is mainly made of metal materials such as special steel plates, super-strong aluminum alloys, or hard non-metallic materials such as ceramics. Although this type of body armor can provide more effective protection, However, it is less flexible and bulky. Military and police generally only use it in very dangerous situations. Soft body armor is also called lightweight body armor. The bulletproof material is mainly made of high-performance textile fibers. It adopts a textile structure. It is light in weight and has considerable softness, so it is comfortable to wear. Military and police officers often wear this type when performing daily tasks. Body armor. Soft-hard composite body armor uses soft materials as the lining and hard materials as the panels and reinforcement materials. It combines the advantages of hard and soft body armor to a certain extent and is the development direction of modern body armor. Body armor is divided into seven levels based on its defensive capabilities. The first category has the lowest defensive capabilities, and the seventh category has the strongest defensive capabilities, usually described by the weapons it can withstand. The lowest levels of body armor can only protect against bullets from smaller caliber, less powerful handguns. Some high-level body armor can protect against rifles with stronger firepower. The first to third categories are basically soft body armor, and the fourth to seventh categories include hardware and composite body armor.
4. The defensive performance and principle of body armor
The defensive performance of body armor is mainly reflected in two aspects. The first is the ability to defend against penetration, that is, to prevent the penetration of bullets or high-speed fragments generated by explosions to avoid direct harm to the human body; the second is the ability to defend against non-penetrating damage, that is, when the body armor is not used, In the case of being penetrated by a bullet, try to minimize the damage caused to the human body by the impact of the projectile or fragments hitting the body armor. The defensive performance of body armor is mainly determined by the bulletproof material and its internal structure.
Body armor prevents the projectile from penetrating by absorbing and dissipating its kinetic energy.It is much stronger than the Kevlar fiber used to make bulletproof vests. This kind of spider web is tougher than steel and very lightweight, 25% lighter than synthetic materials or biopolymers. It has excellent properties such as high strength, good elasticity, softness and light weight, so it is very suitable for making body armor. However, due to extremely limited sources, large-scale production is not possible.
5.6 Liquid bulletproof fiber
The peculiarity of this new type of body armor is that a “viscous liquid” is added to the Kevlar fiber commonly used in making body armor. This liquid is like an energy shield that can react quickly to high-speed objects to protect it, but has no reaction to low-speed objects. Under normal circumstances, this “viscous liquid” is soft and can deform like other liquids. However, once a high-speed shrapnel or warhead touches it, it can instantly transform into a hard material, absorbing the impact of the shrapnel or warhead hitting its surface, and quickly dissipating the huge kinetic energy and impulse of the high-speed flying bullet. . British scientists have tested the bulletproof performance of this body armor and achieved good bulletproof results. At the same time, research and development efforts will be further increased so that “liquid” body armor can not only resist pistol bullets, but also withstand assault rifle fire.
6 Bulletproof vest evaluation indicators
Soft body armor is mainly composed of a bulletproof layer and a jacket. The bulletproof layer is the core part of the bulletproof vest. It is composed of multiple layers of bulletproof materials. Currently, it is mainly aramid materials and high-performance polyethylene materials. Currently, my country has two standards to guide the research and development, production and procurement of body armor, GA 141-2001 “General Technical Conditions for Police Body Armor” and GJB 4300-2002 “Safety Technical Performance Requirements for Military Body Armor”. The more common one internationally is the American body armor standard NIJ 0101.04 “BALLISTIC RESISTANCE OF PERSONAL BODY ARMOR”.
6.1 Bulletproof Speed V50
Bulletproof speed V50 is an important indicator for evaluating anti-fragment performance. It refers to the ultimate speed at which simulated fragments form a penetration probability of 50% on the test sample within the specified bullet speed range. The higher the residual value, the better the bulletproof performance of the bulletproof material.
6.2 Number of penetration layers
It is inaccurate to judge the safety of body armor solely based on the “number of penetration layers”. Because the number of penetration layers is related to the bulletproof material used in the body armor and the weight of the bulletproof material. Under the same protection level, the number of layers of bulletproof materials required for body armor is different. Therefore, the number of penetration layers must be used as the safety evaluation criterion, which can only be used if the same bulletproof materials are used.
6.3 Depth of depression
When considering “dent depth” as a non-penetrating damage performance indicator, the influence of the stiffness of the backing material should be considered. Under the same rigidity, generally the greater the depth of the dent, the greater the corresponding non-penetrating damage. If you blindly pursue a smaller dent depth in the body armor, it will inevitably reduce the comfort and wearability of the body armor. Therefore, as long as the dent depth index is within the standard range (25mm), it is a qualified product.
7 Development Trends of Body Armor
7.1 Focus on the development of bulletproof materials and weaving technology
The focus of bulletproof vests is the development of new bulletproof materials, including hard and soft bulletproof materials. Hard bulletproof materials are required to be thin and dense, with low mass and good bulletproof properties; soft bulletproof materials are required to be soft, have strong tensile and fracture resistance, and have large SP modulus and failure elongation. In addition, bulletproof vests have higher manufacturing process requirements. For example, there are different methods for processing and weaving soft bulletproof fibers, and the waterproof performance, ultraviolet protection, and infrared protection of bulletproof vests also need to be further improved.
7.2 Body armor should be diversified
Body armor should be developed into different styles, colors and patterns according to different occupational requirements and environments to meet the requirements of users. Body armor should be developed in a direction that is both convenient and comfortable for the wearer.
7.3 Body armor is developing towards standardization
At present, most of the bulletproof vests in various countries adopt their own national bulletproof standards, which are inconvenient to use. In the future, they are likely to move towards the use of internationally unified bulletproof standards.
8Conclusion
Body armor is an indispensable protective equipment for modern military and police. Since their introduction, body armor has played an important role in reducing casualties among military personnel and police officers while performing their duties. With the advancement of science and technology, the emergence of new bulletproof materials and the improvement of manufacturing processes, body armor will surely receive further development.
The immediate casualties played an important role. With the advancement of science and technology, the emergence of new bulletproof materials and the improvement of manufacturing processes, body armor will surely receive further development.
