In-Depth Analysis of Bulletproof Vest Technology and Attributes
Rifat Jahangir
Lecturer,
International Standard University, Dhaka
Email: rifatjahangir.ony@gmail.com
1. Introduction
From the ancient time, for every civilization, survival was the basic need. From that era human used various types of weapons, metallic shields like aluminum, steel etc. to protect themselves. But as the civilization is developed the weapons and the protecting shields are also modified to an easier convey. So human always searched for a comfortable protection clothing by which they could survive the attacking weapons. Day by day, when the synthetic textiles are getting very advanced, since then the ballistic materials are developed (Bajaj, 2021).
The materials which are mainly fibrous in nature, are extensively used in the field of manufacturing unique products which are basically used at the goal of ballistic protection. These products are developed on some common criteria like very high tenacity, high modulus of elasticity etc. to being capable of massive amount of strength. But among all these products of ballistic protection, the bulletproof vest is the most accepted textile (Elmogahzy, 2020).
The bulletproof vest is a bulletproof material which has a wide portion of uses. In the military side, it is not only used as a barrier to bullets but also to resist the user from some different military arms like fire arms, mortars, anti-tank weapons, grenades etc. on the other hand, in aerospace section, this ballistic equipment’s are mainly used to defend the aircraft from the outer objects as these spacecraft’s are moving at a very high speed. As these ballistic protection clothing are known to capable of holding very high speed, so these textiles are mainly made of very strong synthetic fibers like aramid fibres poly (phenylenediamine terephthalamide), glass fibres, nylon fibres etc. But sometimes the knit or woven fabrics are also used (Azmi et al., 2019).
But the manufacturing of these ballistic protection clothing is depending on the manufacturer, where various types of materials are used. But recently the para-aramids, ultra-high-molecular-weight polyethylene (UHMWPE) or harder armor materials are generally applied on manufacturing the ballistic-resistant vests. Normally aramid, man-made synthetic fibre that is very exceptionally strong and heat resistant. The very first para-aramid, Kevlar was initiated in 1973 and this type of material provides the ideas like lightweight and flexible armor that was very much available in clothing and effective in protection. The ultra-high-molecular-weight polyethylene (UHMWPE) is another option for ballistic resistant apparels. It is like polyolefin, which is composed of long chains of polyethylene. But leaving everything aside, the newer protective body armor are manufactured form ceramic components with a support of para-aramid like Kevlar (Azmi et al., 2018).
But there is always a tendency to improve the internal features of these protection clothing. So composite material is broadly used as it is a combination of two or more materials both physically or chemically in a smallest range. And the benefit of this composite material is many of the properties of individual material can be combined at one particular material. After all the available properties shown by the composite materials are: fatigue resistance, corrosion resistance, high specific stiffness and strength which are also the criteria of bulletproof vest (Azmi et al., 2019).
Nowadays the researchers are trying to use natural fibres not only in the ballistic cases but also to other applications. X-ray waste and fibre reinforced bio composites have been coated to influence the green composite idea in which by applying a STF (shear thickening fluid) can influence the fabric to promote the ballistic properties of the fabric as it bears a better capacity to receive and minimize the kinetic energy. When the epoxy composite reinforced with jute fabric, it is shown that it can wrestle against the Kevlar (Azmi et al., 2018).
2. Brief History of Bulletproof Vest
2.1 Vest in ancient time
From the initialization of mankind, people all of the time tried to protect themselves from all kinds of wound as they were always in a hurry. So they used various types of materials as their personal protection. On that time mainly animal skins or some hard materials were used as an obstacle to external attacks. But when the armory is getting very advanced metal objects or wooden materials are used as their protective shields.
In the recent century, Roman and Italian royalty were first thought about the concept of developing bulletproof vest in 1500s. from their thinking, they created a body armor where the outer strata were metallic to prevent the high speed bullets and the inner strata was used to prevent the entrance of bullets. But this protective shield could not show proper accuracy against the firearms.
But these metallic shields were very bulky which was an obstacle to the users. So in 1800s, Japan created a body armor where the softer feel was risen and the basic material of that armor was silk fabric which impacted a better result but it was an expensive procedure (The History of the Bulletproof Vest, 2021).
2.2 Vest in Criminal Side
During 1880s, from the crime corner, criminals established protective body suit with combining many types of armors. A criminal named, Ned Kelly, who was a gang leader from Australia, made a body armor with the metallic plates (iron) to protect the major body parts like head and chest. But this protective suit was about 97 lbs. in weight, which was very bulky. He and his family fought against the police in the last battle of their lives, where he was the only surviving soul and then he was arrested. After analyzing his protective body armor, it was found very much effective which was stocked by 18 bullets and this suit was the only means of survival (A brief history of bulletproof vests armor | SOFREP, 2021).

2.3 Soft Body Armor
Then in 1901 when the President William McKinley was killed, the US military became very sincere about their personal protection and they were looking for a soft body armor. Though the expensive silk derived textiles were very active against the bullets but it was not so much effective to high velocity bullets. Since then, the silk based armors use had gradually decreased (The History of Bulletproof Vest, 2021).
2.4 Bulletproof Patents
Then various patents of bulletproof vests are planned to be listed. The U.S Patent and Trademark Office published a recorded list of some designs of protective garments like bulletproof vest and body armor in 1919. The very first recorded example of these garments were exhibited for the use of law enforcement officers, which was thoroughly checked in April 2, 1931, edition of the Washington, D.C., Evening Star, where a bulletproof vest was exhibited to the Metropolitan Police Department (Bellis, 2021).
2.5 Flak Jacket
During the World War II a new type of jacket named, ‘’flak jacket’’ was created as the subsequent generation of ballistic resistant bulletproof vest, which was made from nylon. This flak jacket was not so much protective against the pistol and rifle bullets but it shown a protection from ammunition fragments and this protective cloth was also very bulky, which was a barrier to the soldiers in the battlefield (Bellis, 2021).

2.6 Kevlar
When the synthetic fibre was invented the overall scenario of these derived textiles were changed vernally. In the 1960s, the synthetic fibres were actually tested against the bullets and they were succeed. Since then people had embarked on a new journey of success. In 1970s, when DuPont company discovered the ballistic fabric Kevlar, then some additional features like waterproofing and others were added with Kevlar to create the vest more flexible, wearable and durable. And this fabric was highly strong as the National Institute of Justice could see these Kevlar vests were able to resist the common lead bullets like 38 Specials and 22 Long Rifle Bullets.
You may also like: Kevlar Fiber: Types, Properties, Manufacturing Process and Applications
2.6.1 Research on Kevlar Bulletproof Vests
According to the several tests on that time, Kevlar vests were monitored thoroughly. And the final test result showed that about 95% possibility to survive, when the vest was hit with .38 caliber bullet at a velocity of 800 ft./second and also there is 10% or less possibility of taking surgery after this testing criteria.

Then in 1976, Kevlar was globally accepted as a bullet-resistant by the scientists and it was also modified to light weight for comfort as the military officers had to wear it full-time. Since that time a lot of experiments are being monitored to improve the internal features of bulletproof vest. And in modern times, a level IIIA bulletproof vest is used which is weighted only 5.5 pounds and it can protect the wearer from most of the handgun rounds (The History of the Bulletproof Vest, 2021).
3. Classification of Bulletproof vest
3.1 Classification by State
- Hard body armor
- Soft body armor
3.1.1 Hard Body Armor
The name indicates the characteristics. Normally hard body armors are made of some rigid materials like metal plates, ceramics, reinforced plastics and composites. The standard body armors are formed with the multilayer addition and in this phase the ceramic plates are used to blunt and fracture the bullets and the laminated composite panels are used to stop the running bullets. The hard body armor may also provide an anti-trauma layer which protects the wearer from the dynamic damages. Though the hard body armors are hard as enough to stop the very high velocity bullets but in the advance fields, the ceramic and the composite armor materials have produced lightweight body armors. Hard body armors dissolve the energy with the mechanism of plastic deformation where the kinetic energy of the projectile is dissipated through the fracture of hard material present in the body armor (Ishida & Froimowicz, 2017; Okhawilai & Rimdusit, 2017; Shah et al., 2021; Wang et al., 2014).
3.1.2 Soft Body Armor
This type of body armors is composed of high performance materials, where several layers are used and these high performance materials are produced from ballistic fibres. High strength to low weight, low extension and higher modulus are the most important features of these fibres. These type of fibers are made of advanced woven or other fabrics or like similar structures which can be sewn to produce the vest of soft clothing. These vests are generally used and preferred only for their lightweight, flexibility and comfort properties. But in this type of vests the degree of ballistic protection is totally depends on the quality and feature of yarn, fabric construction and the number of internal layer that is used in the fabric. Besides this, the type of bullets, bullet geometry, bullets velocity and also the impact angle of running bullets affect the level of protection of the soft body armor (Laissy & Ismaeil, 2021; Nurazzi et al., 2021; Wang et al., 2014).
3.2 Classification by Purpose
- Military
- Police
- Civil
3.2.1 Military Bulletproof Vests are separated into:
- Tactical
- Special
- Water inflatable
3.2.1.1 Tactical Vests
These vests impart ballistic protection to the upper part of the body. The front, back and side parts of torso are under the protection of these vests. They are quite easy to carry and allow the wearer to move easily their hands and do not put any resistance to wearer during squatting. These vests are mainly designed as for the use of different tactical actions. The outer layer is made according to the field on which it will be used. These vests with a protection levels IIIA, III under NIJ and levels 4 and 5 under GOST – are mainly used in this criteria.
3.2.1.2 Special Vests
These vests also impart ballistic protection to the upper part of the body. The front, back and side parts of torso and also the protection for neck, throat, shoulders, biceps and loins are under the protection of these vests. During patrolling, these vests are generally used. The outer layer is made according to the field on which it will be used. These vests with a protection levels III and IV under NIJ and levels 6 and 6a under GOST – are mainly used in this criteria.
3.2.1.3 Water Inflatable Vests
These vests also provide the ballistic protection to the front, back and side part of torso and also to neck. The extra feature is the collar of these vests are inflatable by which the wearer can kept him/her on the surface of water. There are also extra belts in these vests, which confirms the safer grip to the body of the wearer during buoyancy. For special and anti-terrorist forces these vests are used and the outer layer of this vest is dependent on the color of the wearer uniform. These vests with a protection levels IIIA, III under NIJ and levels 4 and 5 under GOST – are mainly used in this criteria.
3.2.2 Police Bulletproof Vests are separated into;
- Tactical
- Special
3.2.2.1 Tactical vests
These vests are used to protect the front, back and sides of the torso, which provides the full coverage of torso. They are quite easy to carry for a whole day and offering the liberty of movement of hands during any kind of operation. The outer layer of these vests are generally black. These vests with a protection levels IIIA, III under NIJ and levels 4 and 5 under GOST – are mainly used in this criteria.
3.2.2.2 Special vests
These vests impart ballistic protection to the front, back and side parts of torso and also for neck, throat, shoulders, biceps and loins are under the protection of these vests. During patrolling, these vests are generally used and the outer layer of these vests are generally black. These vests with a protection levels III and IV under NIJ and levels 6 and 6a under GOST – are mainly used in this criteria.
3.2.3 Civil Bulletproof Vests are separated into;
- Ordinary
- VIP
3.2.3.1 Ordinary vests
These type of vests are mainly used to protect the front and back part of the torso from the ballistic protection. Normal civilians and security guards can use these vests. These vests are light weighted and wearer gets satisfaction for a long time using. These vests can be worn below and above the body textiles. These vests with a protection levels I, II under NIJ and levels 1, 2 and 3 under GOST – are mainly used in this criteria.
3.2.3.2 VIP Vests
These type of vests is also used to protect the front and back part of the torso from the ballistic protection. Businessman and high-profiled persons can use these vests. These vests are also light weighted and wearer gets satisfaction for a long time using. These vests are usually carried under the body cloths, which is not noticeable. These vests with a protection levels I, II under NIJ and levels 1, 2 and 3 under GOST – are mainly used in this criteria.
3.3 Classification by the Way of Wearing
- For visible wearing
- For hidden wearing
3.3.1 Visible Wearing
The armor which are used to wear on the body textiles are generally considered in the visible category. These visible armors are mainly suitable for military and police and also some security guards. For police, the outer layer is mainly deliberated in black; for military it is in disguise with different types of matrix and for the guards it is decorated as their color of uniform. The bulletproof vests with a protection level IIIA, III, IV under NIJ are used for police and levels 5,6 and 6a under GOST – are considered for military usage; and protection levels I, II under NIJ and levels 1,2 and 3 under GOST – are used for security guards.
3.3.2 Hidden Wearing
The armor which are used to wear under the body textiles are generally considered in the hidden category. These type are armors are mainly suitable for officials, businessmen and security guards. The outer layer of these vests are generally considered as in white or black which is dependable on the usage. The bulletproof vests with a protection levels I, II under NIJ and levels 1,2 and 3 under GOST – are mainly used in this criteria.
3.4 Classification by the Gender of Individual
- For men
- For women
3.4.1 For Men
For this portion, the bulletproof vests are made by maintaining the standards like colors, patterns of the outer layer. These are used mainly in all categories of ballistic protection and the standards are depending on the intention of usage.
3.4.2 For Women
For this portion, the bulletproof vests are made by maintaining the female body specifications where the standards like colors, patterns of the outer layer are followed. These are used mainly in all categories of ballistic protection and the standards are depending on the intention of usage (Yaneya et al., 2018).
4. Working Principle of Bulletproof Vest
The ballistic performance of a bulletproof vest or bulletproof clothing of the bullet resistant armor of woven structures totally depends on the internal mechanical properties of yarns and fibres used in the procedure. The mechanical properties of yarns and fibres are like high strength fibre, type of weave, linear density of the yarn and weave density. For the case of woven fabric, the form of plain weave, which is woven densely structure is used for the protective clothing. It was estimated that the yarn density that packed in the form of weave for the ballistic fabrics like bulletproof vest is the best from 0.6 up to 0.95 (Chapman,2009; Chen et al., 2005; Sparks, 2012).
Because below 0.6, fabrics are normally very loose, that is why they cannot meet the ballistic requirements and above 0.95 the yarns are very tightly packed and also they have a chance to be damaged during the production process. When the hitting is occurred on the surface of the protection level, which is made of woven fabrics, these hitting of projectile causes a damage of these part of fabrics and begins to spread the yarns apart. This situation is happened when the calibre of bullet size is small. And this small bullet can penetrate the fabric with or without a very small damage of some limited yarns. On the other hand, in case of larger calibre bullets, the yarn is trying to stand as a barrier to the bullets in one of the inner layers, but during this happening, the initial layers and the yarns within them are damaged due to the penetration of large calibre through them. The bullets are getting very slowed by the initial layers and by this time the impact energy of the bullets reduces and is also dissipated. For dissipating the impact energy of the running bullets very quickly and also to offer the maximum protection to the wearer, Unidirectional (UD) shields are used in both soft and hard body armor. That is Dyneema®UD by DSM and Spectra®Shields by honeywell.
In Dyneema®UD all of the yarns like groups or filaments are basically set parallel to each other in the same plane, whereas being woven together. For the case of UD configuration, the fibres of Dyneema®UD approve the transmission of energy from the spot where the bullet strikes by the energy distribution along the fibres much higher than in conventional woven fabrics. This is because the exploitation power of the yarn of woven fabric is totally lost due to the cross points of warp and weft yarns. It is also found that, instead of corroborating the impact energy dissipation process, the cross over points or the cross points rather harm this process (Chen et al., 2005; Sparks, 2012; Spectra fiber, n.d).
Spectra Shield™ is not from woven material, but it is a thin, flexible composite material for ballistic protection, which is made from unidirectional fibres occupied in place by the flexible resins. This Spectra fibres of single layer are placed in such a way that does not allow them to penetrate each other. Then the second layer fibers are placed in completely different angle or direction compared with the fibres of the first layer, e.g. if the fibres of first layer are arranged or kept under 0° then the fibres of the second layer are placed under 90°, but they both of are, in the same plane. After this arrangement, these both layers are sealed between the two very thin sheets of polyethylene film.

This similar arrangement is also applied for the case of Twaron Unidirectional Laminate UD41-or also those associating UD41 with other Twaron materials- which basically grants the different type of benefits for these modern bulletproof vests. These type of vest provide the excellent protection against the running high speed bullets and fragments. It also provides a high comfort to the wearer and excellent performance according to the weight ratios. Twaron UD41 is a unidirectional laminate that is very much suitable and comfortable as a soft body armor. Structural formation of four piles of unidirectional Twaron fibre lines (piled in a 0°/90°/0°/90° configuration, which is represented in the figure).
It makes the proper use of Twaron’s high-fibre tenacity and also avoids the crimping of the woven material. UD technology aligns the Twaron fibres in parallel form in each of the layer and each of the layer is formed in a resin matrix. The top and the bottom UD plies are then laminated. As a result, maximum abrasion resistance can be found (Ciesielska-Wróbel, 2017).
4.1 Working Procedure of Soft Body Armor
Basically the soft body armors are made of with enough flexibility of ballistic materials. This type of vests is generally made of for the protection from the pistols and revolvers like handguns. These vests are generally used for the daily using purpose instead of the hard body armor. If the wearer needs to carry the vest for a long time, then this type of vest is considered for using. Basically law enforcement officers, security guards use this vest and if it is worn under the body textile, then it is said concealable armor.
This vests are generally made of multiple layers of materials, which are ballistic resistant and the type of fabrics that are used like Kevlar fabrics, Spectra or Dyneema UD non-woven materials etc. The overall performance of the vest is totally depending on the number of layers used in the ballistic panels, which expresses the ability to stand against the high speed bullets. The layer is basically works like to slow down the upcoming bullets. Here the upper layers of the protective vest are conjectured to soak and scatter a certain amount of energy, which results the lower affect to the next lower layers. At the time of striking a projectile to the vest, for the woven structures the interlacement of the warp and weft yarns stop the bullets and decrease the rate of penetration of bullets through the vest. These fibres also bear the capacity to soak and fritter away the energy impact of the bullet from the panel to the layers of the vests gradually. This process deforms the bullet. This feature of the vest to absorb and disperse the energy of the high speed bullet is working like a hit of obtuse force without damaging the internal layers of the vest. But besides all these, as the bullet hits the vest, the energy of the bullet shocks the panels to the wearers body. As a result, an injury is occurred in the upper torso of the wearer. The overall scenario is like a cone shaped which is presented in the figure.

This type of injury may cause several type of damage to the wearer body. Like musculature, bones, ligaments fracture etc. (Selection and application guide TO Ballistic-Resistant body armor for law enforcement, correctionsand public SAFETY: NIJ selection and Application Guide-0101.06, n.d.; Sparks, 2012).
Some of the fabric and composite materials which are mainly used in the field of soft body armor is noted below:

4.2 Working Procedure of Hard Body Armor
On the other part, the hard body armor is made off completely opposite of soft body armor, where the rigid panels or plates are used to form the hard body armor. The name “hard” means it will provide the higher protection to the wearer from the higher threats than that of the soft armor. The hard armor plates are mainly used for the tactical vests, where this tactical vests are mainly the combination of hard armor plates and also the soft armor panels. But this vest is more thick as well as heavier than the soft body armor.
The plates of the hard bulletproof vest are generally made of from ceramics, that is compressed with a laminate sheet, metallic plate or composite e.g. CeraShield™ and Cercom® by Coorstek or Tensylon (Ciesielska-Wróbel, 2017; Sparks,2012).
Nowadays Tensylon is used different fields like theatre and also as a spall liner in mine-resistant ambush protected (MRAP) transports. Tensylon HSBD 30A is generally a bidirectional laminate and the hard armor plates are mainly act as a hard shield to the bullets. Here the hard plates stop the bullets or these plates have also a property to break the bullet into pieces. In the both cases, the vest can absorb and then distribute the sudden hit of the bullets impact. Many hard armor plates are basically planned to added with a specific soft armor to get the highest protection from the ballistic weapons. They are placed in the vest by the addition of pockets in the front and back side of the soft body armor carrier. The hard armor plate equipment of the in-conjunction (IC) armor is crystal like noted to define the similar pattern of soft armor panel by which it can be used. Generally, the most used ceramics which can be utilized as stand-alone monolithic plates only for armor related purposes are aluminum oxide (Al2O3), silicon carbide (SiC) and boron carbide (B4C). Al2O3 is mainly the most economical choice, but for the final protection using Al2O3 is major, as Al2O3 has the maximum density and the measly ballistic efficiency from the three of all ceramic types.
B4C is the strongest ceramic material, but at the high pressures, a process named amorphization process collapses the ceramic. This becomes a problem when the threat is coming at very high velocity. Normally the ceramics which has a small grain size can perform better than the ceramics with the larger grain size (Ciesielska-Wróbel. 2017; Rahbek & Johnsen, 2015).

5. Manufacturing Process of Bulletproof Vest
5.1 Fibres Used in Ballistic Protection
In the very beginning, for the ballistic protection woven silk fabrics were basically used. But day by day with the improvement of fibre technology, the high modulus nylon 6.6 which is aliphatic with a very high degree of crystallinity and low elongation is developing, then these type of fibres are used for the ballistic protection widely.
5.1.1 Kevlar
It is a heat resistant and strong synthetic fiber, which was developed by DuPont. And for the personal protection, this fibre is widely used in modern generation as this can produce a lightweight bulletproof vest. The basic features of this fibre is it is built of long molecular chains made from poly-phenylene terephthalamide. These internal chains are highly oriented with a very strong inter chain bonding, results identical combination of properties like low elongation at break, low electrical conductivity, high tensile strength at low weight, low modulus. This finer is also high chemical resistant with low thermal shrinkage and bears better dimensional stability and flame resistance. It is also unaffected by moisture and the strength of this fibre is five times higher than steel with an equal weight.

5.1.2 Twaron
This is a par aramid fibre. The yarn mainly uses 1000 or more finely spun in a single filament which acts as an energy sponge that absorbs the incoming bullet effect and fritter away with a very high instantaneous response. The effect of bullet is spread out through the adjacent fibres. As more of the filaments are used, the impact of bullet is quickly dissipated.

5.1.3 Spectra
It is a very high strength polyethylene fibre. This fibre is produced through gel spinning process where ultra-high molecular weighted polyethylene is dissolved in a solvent. This fibre is 10 times stronger than that of steel, more durable than polyester and the specific strength is 40% higher than that of aramid fibres.

5.1.4 DSM Dyneema
It is of extremely high strength to weight ratio and it is that kind of light where it can float in the water. It can absorb very high energy and can dissipate the shock waves (Malik & Barhanpurkar, n.d).

5.2 Spinning Process Involved In Manufacturing Process
Normally the high performance fibres are very strong in nature, which results the manufacturing process of these fibres require a unique, extraordinary process, which costs high. Generally, gel spinning process is for ultra-high-molecular-weight polyethylene (UHMWPE) fibres. This process ensures the dissolving polymer in a solvent where the ultra-high-molecular-weight polyethylene (UHMWPE) is disentangled into a dilute solution. The dilute solution is spun on basis of melt-spinning type process, where a solvent containing gel fibre is formed upon extinguishing and optionally extracting the first solvent with the second one means of drying or evaporating the second solvent-rich fibre to form a solid fibre.
Then comes the drawing process, where the solid fibre is drawn for several times to improve the internal features of the fibre structure like high strength, high modulus and high orientation.
But for the high cost and solvent recovery steps involved in the gel spinning process, an alternative process was developed to produce high performance ultra-high-molecular-weight polyethylene (UHMWPE) fibres with the use of a compression and sintering process to develop its strength. However, this compressed ultra-high-molecular-weight polyethylene (UHMWPE) fibre has a lower tenacity (about 50%) than the actual gel spinning process.
The aramid fibers are also required a solvent-based process where the rigid aromatic polyamide polymer chain is dissolved by the dry-jet wet spinning process. The high temperature liquid crystal polymer of melt spinning requires a burn down and drawing process where the molecular weight of the polymer is increased for developing the structural features of fibre with a high cost ofmanufacturing. And here the cost of melt spinning process is quite higher than the conventional melt spinning processes of nylon, polyesterand polypropylene etc.
5.2.1 Gel Spinning Process
As the high molecular weight of ultra-high-molecular-weight polyethylene (UHMWPE) polymers, the melt spinning process is not used here like convention nylon or Polyethylene terephthalate (PET). The ultra-high-molecular-weight polyethylene (UHMWPE) polymer will degrade before the flow of it. So gel spinning process is developed for this kind of fibres.

In one solvent gel spinning process, a solvent like decalin is used to detach the ultra-high-molecular-weight polyethylene (UHMWPE) polymer to form a solution, that has 15% concentration. This solution will behave like PET or nylon
Melts at high temperatures and can go through spinneret with the help of conventional melt spinning equipment. After the extrusion from spinnerets, it is then passed through evaporation chamber in which the solvent is started up to form a gel fibre with the remaining solvent. The solid fibre (tenacity about 20g/den) is then drawn to enhance the tensile strength of the fibre with proper alignment.
5.2.2 Dry-Jet Wet Spinning Process
The aramid solution is spun by dry-jet wet spinning process. In here, the anisotropic solution of PPD-T is released through the air gap into a coagulating bath. The resulting yarn after the process is then washed and dried. The basic key of this process is to orient the anisotropic molecule and the elongation of flow through the spinneret pores. The relaxation of the molecule after the extrusion from pores is kept minimum by the filament tension in the air gap and through the coagulation bath as the filament is released in highly crystalline condition. The fibre is also treated in heat to rise the modulus (Tam & Bhatnagar, 2016).

5.3 Winding Process Involved in Manufacturing Process
Generally, the doubler winder is used for the winding process. The whole yarn path passage is designed in such a way that it has to run through four required tensioning device. At that time the total tension obtains about 448 CN. Then the winding speed is kept as much low as possible for removal of machine stoppage due to some unwanted situations like, filament entanglement, filament breakage etc.
Whole of the warping process is then carried out with enough tension being gained by adjusting the angle of leasing rods and all of the tensioning device involved in the machine.
Basically A rigid rapier loom is employed for the whole weaving process with some modification to the let-off mechanism to get high warp tension. As a high dynamic load is generated by high warp tension, the speed of the rapier is come to about 120 ppm. As a result, smooth functioning can be occurred. For the weaving process, the rapier loom is set according to the whole procedure. About 1400 ends of warp yarns, coming from the let-off mechanism are drawn with the eight heald frames and each heald frame contains about 175 ends. To secure the terminal of Dyneema fabric, a leno selvedge is used and also a synthetic yarn of nylon is used for the selvedge formation.
Besides these, a Shear Thickening Fluid is denoted and the recipe of it is also formulated. Due to the suppress of rising the Shear Thickening Fluid, a need of an alternative is arisen. Then the most common non-Newtonian fluid is selected only for simple feature of it. The fluid named Oobleck is the mixture of corn, starch and water and it is developed by using water and corn starch according to the range ratio of 1:1.5 to 1:2. The whole procedure is done at the room temperature.
As in the first trial, Oobleck is introduced and it is laminated as in the package form which is compacted in between the first two layers of Dyneema.
But with the improvement of bulletproof vest, the internal design is also improved. Different studies of possible designs were researched and the most suitable one is chosen for the manufacture.
So the selected design will be one which can be worn over the soldiers and around one side by the insertion of head and one arm through the vest. Thereby it is fixed only in the one side of the body instead of the both sides. The attachment of the side is held with a loop fastener and a hook which will separately stitched on the vest. After the worn, the side will be sealed off. As the sides will cannot have a continuous piece of ballistic panel, a narrow strip will be attached on the both of the sides to stand against the high speed bullets to eliminate their penetration.
Then comes to the outer part of the vest. The material that selected for the outer part of the vest is about weight of 240gsm of 100% cotton fabric. The main feature of this coating is it has a DWR effect of coating, means, Durable Water Repellent coating which will provide the wearer a comfort zone. For this type of coating there will be no effect of wet weather conditions and also it will not increase the weight of the vest in wet condition so to moisture regain. Then the tensile and tearing test of this fabric was done according to the ASTM standards (Fernando et al., 2015).
6. Application field of Bulletproof Vest
Bulletproof vests are used in many sectors, which are represented in the following:
- Police sector
- Military sector
- Journalism sector
- Security sector
- Political sector
The major sectors are briefly discussed:
6.1 Police Sector
From the innovation of body armor, it is seen that in 1973 over than 3000 lives were saved due to concealable or hidden body armor. But in between 1996 to 2005 over than 300 officers were shot and they were died whereas they were wearing body armor and among all these about 31% death caused due to the gunshot in the upper torso (Tompkins,2006).
After that, this scenario tended to improve the internal features of body armor at any cost. But the researchers found out that, sometimes these bulletproof vests were uncomfortable to wear for which officers were reluctant to carry it. But these ballistic vests impact a lot to the officers during the operation (Black, Barker & Cloud, 2010).
For the law enforcement officers, the most common ballistic protection suit is bulletproof vest which is designed according to the officers’ performance and productivity during protecting the major body parts. These protective clothing are planned to design as hidden, rigid or semi-rigid and these must have a protection level from various types of threat levels. When The National Institute of Justice (NIJ) was electing the eligible body armors, they consider the basic criteria like comfort level, protection level and end use of the wearer. For police officers, the hidden ballistic vests (levels I, II-A, II and III-A; Table 1) are mainly used for the lower threat levels. But these vests should be designed as lightweight for comfort and also can be worn under the body textiles which can provide the maximum protection of the front, back, and side parts of the upper torso (Barker & Black, 2009).
Table 1: NIJ armor standards (United States)
Threat level | Caliber | Bullet | Mass (g) | Velocity (m/s) |
I | 0.22 long rifle; 0.380 ACP | Lead round nose; FMJ (Full Metal Jacket) round nose | 2.6; 6.2 | 320; 312 |
IIA | 9 mm; 0.40 S&W | FMJ round nose; FMJ | 8.0; 11.7 | 332; 312 |
II | 9mm; 0.357 Magnum | FMJ round nose; Jacketed soft point | 8.0; 10.2 | 358; 427 |
IIIA | High Velocity 9 mm; 0.44 Magnum | FMJ round nose; Jacketed hollow point | 8.0; 15.6 | 427; 427 |
III | 7.62 mm rifle | Full metal jacketed | 9.6 | 838 |
IV | 0.30 calibre rifle | Armour piercing | 10.8 | 869 |
(Barker & Black, 2009; List of body armor performance standards-Wikipedia, 2021). The provided vests for the police are constructed with multiple layers, which are ballistic resistant fabrics and these vests should be wrapped around the upper torso, where the major body organs are kept in additional protection (Black, Barker & Cloud, 2010).
6.2 Military Sector
For the military purpose ballistic protection is an important issue and this issue related equipment such as bulletproof vest or helmet is the most important thing for saving a soldier’s life at the battlefield. Though these vests are mainly used for law enforcement officers but nowadays these protective clothing are available in different sections.
According to the research of Peleg’s work which was based on the injuries due to the terror attack in Israel. Two parts were considered to compare. They were the soldiers wearing vests and the normal civilians who were defenseless. The research had shown that, death rate of the civilians was quite higher than the same of military. About 37 people of civilians were died whereas only 8 for the soldiers. These data’s again proved that these vests were designed to protect the upper torso of the human body. It was found that around 23% was the chest injury where among the chest injury 27% injury was for civilians and only 15% was for the soldiers. The injury severity of that time was scored by Injury Severity Score (ISS) and according to the Peleg’s research the comparison of injury among civilians and soldiers was like (Zwolińska et al., 2013),
Table 2: Comparison of injury characteristics by patient group
Feature | Total | Civilian | Soldier | |||
Criteria | N (Number) | % | N (Number) | % | N (Number) | % |
Total | 669 | 100 | 433 | 64.7 | 236 | 35.3 |
ISS 1-8 | 336 | 50.8 | 198 | 46.5 | 138 | 58.5 |
ISS 9-14 | 158 | 23.8 | 97 | 22.8 | 61 | 25.8 |
ISS 16-24 | 70 | 10.6 | 51 | 12.0 | 19 | 8.1 |
ISS 25+ | 98 | 14.8 | 80 | 18.7 | 18 | 7.6 |
Missing | 7 | |||||
ICU | 161 | 24.1 | 114 | 26.3 | 47 | 19.9 |
Inpatient death | 45 | 6.7 | 37 | 8.6 | 8 | 3.4 |
So from these data, it is very clear the vests could protect the soldiers from the ballistic attacks whereas the injury percentage was quite higher for civilians and that’s why the bulletproof vest for the soldiers during the military action is very important and it can provide a massive protection to a soldier from the opponent (Peleg et al., 2006).
But for the soldiers the bulletproof vests should have another important criterion. During the military operations, it is not always easy to fight against the opponents wearing a bulky protective clothing. So reducing the weight of the military bulletproof vests is very important for the comfort of the soldiers. It was found that during the operations, without other equipment, only vest was approximately 8 kg, which was very bulky and tended the soldiers to an exhausted condition and this heavy weight increased the pain of the soldiers during walking, jumping, and running in the field. More particularly, the number of pull-ups, stair steps, hurdles, wall climbs, the duration of hanging time and also the uphill walking etc. were decreased by 16-63%. When the soldiers wore a bulky bulletproof vest, the performance rate of these actions also reduced to 12-44% which also forced the soldiers both mentally and physiologically. Heart rate and oxygen consumption also increased in a higher rate during the actions when soldiers wore the military ballistic vests.
Table 3: GOST armor standard Russia
Threat level | Caliber | Bullet | Mass (g) | Velocity (m/s) |
1 | 9*18 mm Makarov 7.62*38 mmR | 57-N-181S steel-core bullets 57-N-122S lead-core bullets | 5.9; 6.8 | 305-325; 275-295 |
2 | 5.45*18 mm 7.62*25 mm Tokarev | Steel-core MPC 7N7 bullets Steel-core bullets | 2.5; 5.5 | 310-335; 415-445 |
2A | 12 gauge | Lead-core “Hunter” shotshells | 35 | 410 |
3 | 5.45*39 mm 7.62*39 mm | 7N6 (PS) Hardened steel-core bullets 57-N-231 (PS) Hardened steel-core bullets | 3.4; 7.9 | 890-910; 710-740 |
4 | 5.45*39 mm
| 7N10 (PP) Hardened steel-core bullets | 3.4 | 890-910 |
5 | 7.62*54 mmR 7.62*39 mm | 57-N-323S steel-core bullets 57-N-231 (PS) Hardened steel-core bullets | 9.6; 7.9 | 820-840; 710-750 |
5A | 7.62*39 mm | 57-BZ-231 (BZ API) armor-piercing incendiary bullets | 7.4 | 720-750 |
6 | 7.62*54 mmR | ST-M2 Hardened steel-core bullets | 9.6 | 820-840 |
6A | 7.62*54 mmR | 7-BZ-3 (B32 API) armor-piercing incendiary bullets | 10.4 | 800-835 |
So it was totally crystal clear that the weight of the vests impacted the performance of the soldiers during the action. But it was hard to minimize the weight of the military bulletproof vests as there were several layers of aramid fabrics and ceramic plates for protection. By focusing on this journey the weight of these vests are now lowered to 5-6 lbs. or 2-2.5 kg for the better performance of the soldiers in the battlefield (Lee et al., 2013; List of body armor performance standards- Wikipedia,2021).
Normally the bulletproof vests of protection levels IIIA, III, IV under NIJ (Table:01) and levels 4,5,6 and 6a under GOST are used for the military section and these vests are designed to lightweight and comfortable to carry and these provide a great protection to the front, back and side parts of the upper torso as well as to neck, throat, shoulders, biceps and loins (Yaneya, et al, 2018).
6.3 Journalism Sector
All over the world, investigative journalism (IJ) is getting very popular and it is receiving academic critical observations and the major parts of the observations which are focused on institutional challenges, publishing, financial, content analysis and the global west. And for investigative journalism (IJ), wearing protective clothing is a mandatory feature for the personal safety of everyone (Meyer, 2019).
But for gathering the output, a journalist should be fully equipped with the protections. Such as in the extreme conditions, it can be involved such wearing hazmat suits, carrying detectors, ingesting tablets to act against the possible biological, chemical agents. In the battle zones, a body armor is must to withstand the high speed bullets. And in the case of street percussions it is also required to wear an inexplicit anti-stab protecting vest.
Journalists also require the protecting vests on basis of the expected thread. The National Institute of Justice (NIJ) has introduced a six levels of protective vests, which are used by most of the manufacturers over the world. For covering the war zone, the bulletproof vests as well as the helmets are also used by the journalists. But as a journalist it is really needed to wear the light weighted body armor which can stop the scratches of knives and rubber bullets during the street percussions covering (Smyth, 2018).
But all over these conditions, the impact of working efficiency is totally depending on the body movement. For telecasting it is mandatory to bear some equipment’s during the action. At that time knee pain, back pain etc. are common orthopedic problems which is occurred from the carrying heavy weight. As a result, if a high bulletproof vest is also included, then it will become more difficult which tends the journalist to less working efficiency and these difficulties should be prohibited by using a light weighted bulletproof vest, so that a journalist can easily take the scenes (Park et al., 2011).
7. Advantages
Nowadays the protective clothing is showing their use quite efficiently. Along with the military and army, bulletproof vests are used by security, political figures who need protection from the oppositions encounter badly as well as the wealthy film stars are also use them. These vests are already included with their lifestyles as these provide a serious protection. Most of the time, at the time of actions, if a round is hit on the upper torso of anybody, this vest can defend them from unwanted accidents and injuries. During choosing the vest it is mandatory to be conscious. Becauseall vests are not suitable for all usage. It should be relaxing and allowed the wearer to shift anywhere in the blink of an eye. In the midst of all these, it offers some advantages, which are very trivial. The highlighted benefits of the bulletproof vest are given below:
These vests provide not only the security and protection but also a mental relaxation to the wearer, which can defend any kind of unwanted circumstances to the person who bear it.
The people who can use these type of vests can preserve them from different types of ballistic accidents.
These vests also protect from the inner accidents to the wearer from the mysterious factors (Ballistic Vest and bulletproof material benefits of having with- cigeogroup, 2021).
As the body armor is fitted to the wearer body, wearer can get the proper comfort and fit level, which tends the wearer to get flexibility at the time of action and it increases the working efficiency of the worker (Burton, 2021).
From the military side, the vests in which the nanotechnology is used it offers two important features. One of these is, the possibility to get high degree of miniaturization and this will reflect the weight of the vest and the other one is to get the unexpected effects in the nanoscale range and this will effect as a representation of strategic advantage over the opponent and also cover up the technology used behind (Castaño & Rodriguez, 2021).
The Kevlar used bulletproof vest can protect from the high speed bullets and also able to absorb and evacuate a large amount of energy which means it can resist some major attacks and protect the wearer at its best.
The light weighted bulletproof vest provides the carrier enough opportunity to do his/her work with higher working efficiency and also with the high grade of protection (“The Unexpected Benefits of a Bullet Proof Vest | Wilderness Survival Product Reviews”, 2021).
The concealable or hidden body armor which are of levels IIA, II AND IIIA under National Institute of Justice, can protect the carrier from the sudden attacks and it is proved that the law officers who do not bear a bulletproof vest have a risk of dying is quite 3.4% higher than the vest carrier.
So it is justified that, the bulletproof vest is basically designed to protect from the ballistic attacks to the wearer from different corners such as military, police, political issues etc. and it provides various advantage to the wearers. But besides all of these, it can ensure to save a life from the death corner, which is the mandatory feature at the top of all.
8. Disadvantages
Everything has its own negative sides and in this case, there are some drawbacks of the bulletproof vest, which cause a lot of negative results like discomfort, increasing stress, reducing mobility etc. and these problems are discussed below:
Some studies show that the heavy bulletproof vests are mainly leading to the muscular related problems like back pain, knee pain, neck, upper extremity, low back etc.
Heavy bulletproof vests also ruin the working performance and the mobility. After all, an unequal weight distribution can hamper the body balance and also the function if leg muscle.
Sometimes the core temperature is increased while wearing the bulletproof vest and it influences the working efficiency of the military and law enforcement officers. Different studies show that at the time of performing with wearing vest, the oxygen consumption rate, heart rate and also internal temperature rate is raised. As a result, it also decreases the cardiovascular strain performance and influences the heat related problems.
Most of the ballistic vests are not custom made, but a sized item with actual size range, highest comfort etc. cannot be guaranteed. As a result, fit issue of vests is undoubtedly a major issue, which can focus on the discomfort and mobility issues of the wearer.
Modern bulletproof vests protect only the chest from the fatal injuries but it does not offer any protection to the neck, limbs and face. And these sections are totally open to the ballistic equipment. Therefore, in the battlefield, head, face, neck damages are the common injuries for the soldiers.
These problems should be sincerely considered as a bulletproof vest plays a high role in the field of ballistic protection and the users should select the vest as their own standard to remove the drawbacks (Perry, 2018).
9. Conclusion
The overall feature of this scenario expresses the significance of the bulletproof vest in the different type of sections in our day-to-day life. And wearing a vest is the major part for the military police or others in the combat zones. As it provides the maximum protection to the wearer, so it is mandatory to be quite comfortable to the carrier and nowadays a lot of research can be occurred to distribute the weight properly as a result, for the better weight distribution, wearer can get enough working efficiency and enough mobility in the combat zones. Besides all these, the bulletproof vests are properly manufactured in such a way that wearer can carry this vest for such a long time. And finally, as the vest can provide another chance for living, so its usage is increasing day by day and the internal features are getting improved for better performance (Park et al., 2013).
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.