- Bulletproof plate
- Bulletproof shield
- Bulletproof vest
- Is bulletproof vest also stab-proof?
- Ballistic helmet
- Alumina plate
As an indispensable bulletproof device in military activities, the bulletproof plate serves widely in armed forces, security agencies, and the Department of Defense Analysis. It is essential to have a good understanding of the operation method and how to wear them properly.
Bulletproof plates must cover the parts above the navel and below the clavicle of the body to better protect the essential organs such as the heart and lungs from damage. Therefore, it is ideal that the upper edge places close to the clavicle, and the lower edge close to the bottom end of the last row of ribs, about one inch from the navel (injury to parts below the navel will not be fatal), so that all vital organs protect without hindering the action. Currently, most bulletproof plates are uniform in size because of manufacture, according to the US SAPI specification (W9.5cm*H12.5cm/W24.1cm*H31.8cm).
But different people may vary in height. So, it is essential to properly wear the ballistic plate, which can be adjusted by the tactical vest or the Velcro on the body armor.
The bulletproof plate can be divided into STA (stand-alone) hard armor plate and ICW (in conjunction with) hard armor plate by protection type. STA plate can be used separately in tactical vest without bulletproof capability, while ICW plate should be used in cooperation with an NIJ IIIA ballistic vest.
The bulletproof plate often comes in curved type (single-curved plates and multi-curved plates) and flat.
There are generally shooters cuts (SC) at the upper edges of some plates to facilitate the standard shooting action, and asymmetrical corner cuts called advanced shooters cuts (ASC) in other plates to adapt to the different motion amplitudes of the left and right arms when shooting.
Most people choose bulletproof plates from aspects in the protection level, material, and pricing.
In terms of materials, the mainstream bulletproof plates are ceramic, PE plates, and steel plates.
Available standards on the market that characterize the protection level, include the US NIJ standard, German standard, and Russian standard.
For decades, the advent of high-performance fiber materials has facilitated the replacement of bulletproof plates.
Concerning military bulletproof products, the weight has always been an important consideration.
Having a high protection level, and greater weight worries costumers. A high-performance fiber plate for PE plate has addressed these concerns quite well. It is much lighter than metal and ceramic plates under the same protection level. Moreover, high-performance fiber plates divide into PE plates and aramid plates.
What is the difference between them?
PE bulletproof plate here refers to UHMWPE (ultra-high molecular weight polyethylene) with a molecular weight between 1 and 5 million amu.
Polyethylene products can be found everywhere in our daily lives, such as the plastic bags and beverage bottles featuring extreme stability, low degradability, low specific gravity, high modulus and resistance to low temperature, UV, soak, acid and alkali, which make it the optimal material for bulletproof plates. It is even required for ceramic plates as a backing plate. Generally, PE bulletproof plate has become a relatively high-end product on the market.
Aramid, also known as Kevlar, is a new high-tech synthetic fiber born in the late 1960s. Featuring high-temperature resistance, creep resistance, lightweight, and high strength, broadly used in fields including bulletproof equipment, construction, and electronic equipment. It is more suitable than PE when used in high-temperature areas. But its fatal shortcomings like vulnerability to UV, facile hydrolysis, poor stability, and short service life limit its further application in the field of bulletproof equipment.
Due to the structure of materials, the protective performance of aramid is worse than that of PE. Besides, aramid is denser than the PE plate of the same protection level and is usually more expensive because of its limited quantity.
In summary: PE plate is fitting in areas with high humidity and strong light, while aramid is recommended to be used in high-temperature and dry areas.
In recent years, the composite armor consisting of high-performance fiber and high-strength ceramic has gained global popularity and become a mainstream structure.
Ceramic armor can not only be installed on military vehicles to strengthen the defense capability, but also be used for personal protection. The use of ceramics can be traced back to 1918. With great hardness, ceramics can crush the bullet the moment of contact to reduce the impact of the projectile. It is usually used in conjunction with soft body armor for personal protection.
Currently, bulletproof plates can be made out of various ceramics, the most commonly used, which are, alumina, silicon carbide and boron carbide, among which boron carbide is the strongest but the most expensive. Silicon carbide has density and hardness that are similar to that of boron carbide. With moderate price, it is more extensively applied for withstanding the attack by large projectiles.
Bulletproof ceramics have many requirements for its properties, such as density, porosity, hardness, fracture toughness, Young's modulus, sound velocity, and mechanical strength. Any of which cannot be directly related to the overall ballistic performance. The fracture mechanism is hugely complicated, with cracks that are caused by many factors in a short time. The porosity of the bulletproof ceramics should be as low as possible to increase the hardness and Young's modulus. For Al2O3 ceramic, the porosity should be close to zero, the water absorption should not exceed 0.02%, and the hardness should exceed 1220～1250 because the hardness of ceramic is required to be higher than that of the projectile.
The speed at which sound propagates through the ceramic indicates the ability to dissipate energy on the impact surface of ceramic, so the high sound velocity also indirectly shows sufficient densification and low porosity of ceramics.
In addition, there are processing techniques such as sintering, reaction bonding and hot pressing for composite bulletproof ceramic materials, which are continuously emphasized and innovated.
Bulletproof shields on the market are classified by usage type into handheld bulletproof shields, mounted on wheel-based frames, and special bulletproof shields.
There are usually two handles on the back of handheld shields to facilitate both left-handed and right-handed users.
The bulletproof shield equips ballistic glass speculum for external observation.
Handheld shields serve for more complex combat scenarios. For example, they are more flexible and can work better with weapons such as guns in narrower stairs or corridors.
Handheld bulletproof shield mounted on the wheel-based frame is equipped with a trolley to save labors for long-distance movements, two handles on the back for hand-holding, and also a glass speculum for external observation. Generally, shields of higher protection levels are heavier, so a trolley to transport it.
This kind of bulletproof shield is mainly suitable for relatively open and flat battlefields. The shield can be moved freely on the wheel-based frame over a long distance, and it can also be handheld when necessary.
Special bulletproof shields
Special bulletproof shields usually have specialized structures to realize more diverse functions. For example, the ladder-type bulletproof shield with a particular structure on the back can be transformed into a ladder to cope with complex terrain, to help users observe and adapt to a higher altitude environment. Meanwhile, the bottom of the shield furnishes with wheels, which perform the movement more convenient and labor-saving.
There are also a variety of shields with different special functions on the market, such as shields that can be quickly unfolded and folded and concealed shields that can turn into briefcases.
There are also many materials used to make bulletproof shields, mainly including metals, ceramics, and pure ballistic fibers.
Firstly used in history, metal shields usually have significant weight and unsatisfactory protective performance. But they are still applicable to prevent lower threats such as pistols.
The emergence of PE and aramid is a big leap in the application of high-performance materials because they can significantly enhance the defensive capabilities of bulletproof shields while reducing their weight. However, the pure bulletproof fiber shield is limited in the ability to stop rifle armor-piercing ammunition and armor-piercing incendiary bullets. Now, bulletproof shields prepared from composite materials have gained popularity in the market, which can effectuate better protection.
The combat scene should be taken into consideration when choosing bulletproof shields. For example, a light-weight and portable shield are preferred in tactical activities in a narrow and complex field, while a bulletproof shield with greater protection area and a higher protection level is needed in the open and flat battlefield.
Fundamentally, the bulletproof mechanism of the bulletproof vest is to bounce off the fragments formed by projectile fragmentation and to release the kinetic energy of the warhead through the ballistic material. This body armor and similar hard bulletproof vests are bulletproof by bouncing off the bullet or shrapnel, or by fragmenting the ammunition to decompose its energy consumption. The soft bulletproof vest with high-performance fiber as the primary ballistic material mainly follows the latter mechanism.
Researches show that soft bulletproof vests absorb energy through the following ways:
(1) Fabric deformation: including deformation of the incidence direction of the bullet and tensile strain of the vicinity of the incidence point;
(2) Fabric destruction: including fibrillation of fibers, fiber breakage, the disintegration of yarn structure, and disintegration of fabric structure;
(3) Thermal energy: energy dissipates by friction in the form of heat;
(4) Sound energy: the energy consumed by the sound emitted by the bullet after hitting the bulletproof layer;
(5) Projectile deformation. When a bullet hits the body armor, it firstly interacts with the hard-ballistic materials such as steel plates or reinforced ceramic materials. During this moment of contact, both the bullet and the hard-bulletproof material may deform or break, consuming most of the energy of the shot. The high-strength fiber fabric absorbs and diffuses the remaining energy, acting as a buffer to minimize non-penetration damage.
The bulletproof vest has altogether developed three generations. The first generation is the hard-bulletproof vest mainly made of ballistic metals like special steel and aluminum alloy. It is so bulky that it is about 20kg in weight, uncomfortable to wear, bulletproof, and prone to secondary fragmentation, having more considerable restriction on human activities.
The second generation is the soft bulletproof vest, usually made of high-performance fiber fabrics such as multi-layer PE. It is light in weight, often only 2 to 3kg, smooth in texture, comfortable to wear, and concealable enough for police and security personnel or political figures to wear in daily life. In terms of bulletproof ability, it is generally able to prevent bullets fired from pistols 5 meters away without producing secondary shrapnel, but it will be significantly deformed after being hit by bullets, which may cause certain non-penetrating damage. Besides, soft body armor with standard thickness has difficulty in resisting bullets fired from rifles or machine guns. The third generation is the composite bulletproof vest with light-weight ceramic sheet as the outer layer and high-performance fiber fabric like PE as the inner layer, which has become the main development orientation of bulletproof vest.
The bulletproof vest has altogether developed three generations.
The first generation is the heavy (20kg), hard-bulletproof vest mainly made of ballistic metals like special steel and aluminum alloy. It is uncomfortable to wear, bulletproof, and prone to secondary fragmentation, having larger restriction on human activities.
The second generation is the light (2-3kg) soft bulletproof vest usually made of high-performance fiber fabrics such as multi-layer PE. It is comfortable to wear and concealable enough for police and security personnel or political figures to wear in daily life. It is generally able to prevent bullets fired from pistols 5 meters away without producing secondary shrapnel, but it will be deformed greatly after being hit by bullets, which may cause certain non-penetrating damage. Soft body armor with normal thickness has difficulty resisting bullets fired from rifles or machine guns.
The third generation is the composite bulletproof vest with lightweight ceramic sheet as the outer layer and high-performance fiber fabric like PE as the inner layer, which has become the main development orientation of bulletproof vest.
Are bulletproof vests also stab-proof?
In popular belief, bulletproof vests must be "able" to protect you from being stabbed by knives, shanks, razor blades, or any other blunt point. But unfortunately, a bulletproof vest is not necessarily stab-resistant.
An ordinary bulletproof vest composes of Kevlar material. When the warhead hits the ballistic vest, it achieves the bulletproof effect. That is to say, the impact kinetic energy of the warhead shares to each Kevlar fiber. But what's produced in stabbing by knives is shear stress that is perpendicular to the fiber. The energy density of the knifepoint is much higher than that of the warhead. So, the ballistic vest is not necessarily stab-resistant because fiber has the worst resistance to the shear stress in a vertical direction.
Moreover, the impact of a high-speed reinforcement bomb on the bulletproof vest is different from the effects of sharp weapons. The energy dispersion of the former realizes mainly by projectile deformation, fiber breakage, and shock wave propagation.
Presently, there is no single type of soft bulletproof vest on the market which can pass the test of puncture resistance to 900N force specified by the GA68-1994 standard, and also cannot reach the dynamic puncture performance of 25J defined by the new rule of the stab-resistant vest to be issued.
Indeed, the soft bulletproof vest has a particular anti-stab ability, which is determined by the structure of the body armor (mainly the structural composition of the ballistic material). So only the special stab-resistant vest can reach the required stab-resistant standard.
Longkui can provide high-quality stab-resistant products.
A soft stab-resistant vest made from stab-proof materials blended by polyethylene chopped strands, and aramid chopped strands with ultrahigh strength, and density is designed to protect the human torso and internal organs from knife attacks like stabbing, cutting and slashing.
Many people think that bulletproof vest must be able to protect you from being stabbed by knives, shanks, razor blades, etc. But unfortunately, bulletproof vest is not necessarily stab resistant. Why?
Ordinary bulletproof vest is made of Kevlar material. When the warhead hits the ballistic vest, the tough Kevlar fiber will transmit the kinetic energy of the warhead to the entire body armor, thus achieving the bulletproof effect. That is to say, the impact kinetic energy of the warhead is shared to each Kevlar fiber. But what produced in stabbing by knives is shear stress that is perpendicular to the fiber, and the energy density of the knifepoint is much higher than that of the warhead, so ballistic vest is not necessarily stab-resistant because fiber has the worst resistance to the shear stress in vertical direction. Moreover, the impact of the high-speed reinforcement bomb on the bulletproof vest is different from the stabbing and impact of sharp weapons. The energy dispersion of the former is mainly realized by projectile deformation, fiber breakage and shock wave propagation, while the stabbing of knives is based on the shearing principle that within a narrow energy dispersion range, a sharper bayonet is less likely to be prevented.
At present, there is no single type of soft bulletproof vest on the market can pass the test of puncture resistance to 900N force specified by the GA68-1994 standard, and also cannot reach the dynamic puncture performance of 25J defined by the new standard of stab-resistant vest to be issued. Certainly, soft bulletproof vest has a certain anti-stab ability, which is determined by the structure of the body armor (mainly the structural composition of the ballistic material). So only the special stab-resistant vest can reach the required stab-resistant standard.
Longkui is able to provide you with high quality stab-resistant products.
A soft stab-resistant vest made from stab-proof materials blended by polyethylene chopped strands and aramid chopped strands with ultrahigh strength and density is designed to protect the human torso and internal organs from knife attacks like stabbing, cutting and slashing.
Initially, helmets were only used to provide soldiers with head protection against fragments (stones and metal fragments splashed on the battlefield) during the war. The V50 value is generally used to judge the defensive ability of the helmet, the higher the V50 value, the better the helmet performance.
With the rapid development of materials science from the late 20th century to the 21st century, a variety of materials suitable for making helmets have been developed. Now there are mainly three materials used to make ballistic helmets, including PE, Kevlar and bulletproof steel.
PE has occupied a larger share in the market of ballistic materials for its simpler maintenance, stronger bulletproof ability, high strength, high modulus, light weight, anti-corrosion, acid and alkali resistance, weather resistance, and higher cost performance. But its performance will be affected under high temperature above 90℃, so it cannot be used under high pressure for a long time due to the poor creep resistance, or it will be deformed easily. To solve this problem, some manufacturers are researching and developing ballistic helmet blended by Kevlar and PE, which is inspiring for our R&D team, and we will try our best to provide users with better helmets.
Kevlar, also known as aramid, is one of the mostly widely used ballistic materials for helmets for its high-temperature resistance, light weight, great strength and great anticorrosion. However, it is vulnerable to UV that it will degrade when exposed to UV, and is easy to hydrolyze that can absorb moisture even in dry environment, thus its protective performance and service life will be greatly reduced in the environment with strong ultraviolet light and high humidity. Although it has some disadvantages in elastic resistance and price compared with PE, its great creep resistance and anti-deformation ability make it more popular in bulletproof industry.
Bulletproof steel is the earliest material used for ballistic helmets. It is much cheaper but much weaker in bulletproof capability than Kevlar and PE. It is harder and stronger than ordinary steel, but is heavy and uncomfortable to wear.
Many helmets are now able to defend against pistols and even rifle bullets. Most of our ballistic helmets have a protection level of NIJIIIA, which can prevent the direct penetration of 9mm parabellum and .44 magnum at a distance of 15 meters, which greatly improves the survivability of soldiers.
With the evolution of war and the development of science and technology, the defense capability of ballistic helmet is constantly upgraded, and it is necessary to be cooperatively used with some auxiliary combat equipment, such as night vision goggles, communication equipment, etc. Therefore, helmets have developed in various shapes and functions to meet the requirements of modern combat scenarios. At present, there are three main types of ballistic helmets on the market: PASGT, MICH and FAST, which have some differences in structure and function, and you can choose the most suitable one according to your own needs.
PASGT is the acronym for Personnel Armor System for Ground Troops. PASGT helmet was the first combat helmet used by the US military in 1983 and was eventually adopted by many other military and law enforcement agencies in the world. The outer shell is usually composed of multi-layer Kevlar, whose protection level is rated as IIIA by DARPA, USMC and the US Army, so it can prevent shrapnel and ballistic threats. In addition, accessories such as mounting brackets can be installed for equipment like night vision goggles and flashlights to meet different needs.
MICH helmet (Modular Integrated Communications Helmet) was developed as an improvement of PASGT helmet. It is shallower than PASGT helmet, whose visor, chinstrap, sweatband and nylon cord suspension system are replaced by a four-point retention system and a pad system, which make MICH helmet more comfortable and more defensive. The helmet is usually made of advanced Kevlar, and is resistant to pistol bullets. In addition, accessories such mounting brackets can be installed for equipment like night vision goggles and flashlights to meet different needs.
The most important feature of MICH is that a duplex communication module can be installed under the earflaps to replace the bulky headset system, which can better match with the modern communication equipment, and provide a multi-functional mounting bracket for accessories.
FAST is the abbreviation of Future Assault Shell Technology, not meaning high speed. On the premise of meeting the protection requirements and minimizing the protection area, FAST helmet is designed as light and comfortable as possible. The high cut enables soldiers to use most communication devices when wearing this helmet. In addition, accessories such mounting brackets can be installed for equipment like night vision equipment, tactical lights, cameras, goggles, face shields and the like to better meet the needs of modern war informationization. The difference in the height of ear cuts of various FAST helmets results in the differences in protection area and structure.
In conclusion, these three types of ballistic helmet have their own special structural features and functions, which should be reasonably chosen according to material characteristics, usage scenarios and actual needs. Currently, there are three main materials for making ballistic helmets: bulletproof steel, Kevlar and UHMWPE, among which PE is now gradually replacing aramid as the most popular ballistic material in the bulletproof market due to its own characteristics.
Alumina plates are popular in industries of machinery manufacturing, automobile, household appliances, and handicrafts not only for its durability and appearance but also for the exceptional corrosion resistance, scratch resistance, and uncharged surface.
1. Excellent corrosion resistance:
The most crucial difference between the oxidized aluminum plate and the un-oxidized aluminum plate lies in the corrosion resistance.
2. Scratch resistance: There will be a layer of oxide film formed on the surface of an un-oxidized aluminum exposed to the air for a period, which is not protective, and the performance will change with time. However, a hard wear-resistant layer will form after unique oxidation, with the surface hardness reaching the sapphire grade and the Mohs hardness of 9.
3. Uncharged surface: metal is a conductive material, whose surface can quickly generate charges that will absorb dust and dirt, shadowing the initially bright surface. Alumina plate exactly turns the fully charged plate into an insulator, protecting the surface from dust, therefore making it easier to clean.
Types of alumina plates
1. Anodized alumina plate
The anodized alumina plate is a kind of practical alumina plate with the surface coated with a particular thin layer of alumina, which increases the hardness and wear resistance of the alumina plate. Meanwhile, the anodized alumina plate has high fire resistance due to its extremely high melting point. Anodized alumina plate is also easy to color and aesthetically pleasing.
2. Chemical alumina plate
The chemical alumina plate is mainly produced by chemical reactions, after which the thickness of the oxide film is thickened, which improves the oxidation resistance and durability of the chemical alumina plate. Meanwhile, the chemical alumina plate is also easy to color and can be enhanced.
However, there may be a color difference of all alumina plates, why?
The color difference of the alumina plate may result from various factors, such as raw materials, treatment chemicals, treatment time, or processing temperature. The color difference of the alumina plate is unavoidable and is also the characteristic of anodized alumina plate. Moreover, a color difference range will be standardized by companies to ensure producing qualified products within reach.