The document discusses ballistic protective materials used in military and civilian applications. It describes that ballistic protection works by arresting projectiles over a short distance using high modulus textile fibers with high strength and low elasticity. Common fibers used are para-aramid fibers like Kevlar and Twaron, and ultra high molecular weight polyethylene fibers like Dyneema and Spectra. These fibers absorb kinetic energy through weaving the fibers into loose, multilayer fabrics of 5 to 20 layers sealed in a waterproof cover to withstand bullets, shrapnel, and explosives.

1. Ballistic protective materials
Tuesday, February 15, 2011, 03:00 PM
Posted by Administrator
6.10 Ballistic protective materials
Most military casualties which are due to high speed ballistic projectiles are not caused by bullets. The main threat is from fragmenting
devices. In combat, this means, in particular, grenades, mortars, artillery shells, mines, and improvised explosive devices (IEDs) used by
terrorists. The main cause of injury to civilians (including police officers) has been bullets.
These can be classed as ‘low velocity’ bullets fired from hand guns (revolvers, pistols) at close range. ‘High velocity’ weapons, such as rifles
and machine guns tend to be used at longer ranges. Generally speaking, the velocity itself is less important than the kinetic energy, bullet
shape, or composition of the bullet
6.10.1 Textile materials for ballistic protection
Ballistic protection involves arresting the flight of projectiles in as short a distance as possible. This requires the use of high modulus textile
fibres, that is those having very high strength and low elasticity. The low elasticity prevents indentation of the body and subsequent bruising
and trauma caused by the protective pack after impact. Woven textiles are by far the most commonly used form, although nonwovens felts
are also available.
One of the earliest materials used was woven silk, and work done in the USA has examined the use of genetically engineered spiders silk to
provide protection. High modulus fibres based on aliphatic nylon 6-6 (ballistic nylon), have a high degree of crystallinity and low elongation,
and are widely used in body armours and as the textile reinforcement in composite helmets.
Since the 1970s a range of aromatic polyamide fibres have been developed (paraaramids).These are typically based on poly-para
benzamide, or poly-para phenyleneterephthalamide. Fibres with tradenames such as Kevlar® (Du Pont) and Twaron® (Enka) are available
in a wide range of decitexes and finishes.
A range of ultra high modulus polyethylene (UHMPE) fibres have been developed.They are typically gel spun polyethylene (GSPE) fibres,
with tradenames suchas Dyneema® (DSM) and Spectra® (Allied Signal). Fraglight® (DSM) is a needle felt fabric having chopped, randomly
laid GSPE fibres.These GSPE fibres have the lowest density of all the ballistic fibres at about 0.97 gml-1. The main disadvantage of these
fibres is their relatively low melting point at about 150°C.
6.10.2 Fabric types and compositions:
The majority of ballistic fabrics are of a coarse loose plain-woven construction. Continuous multifilament yarns with the minimum of producer
twist tend to give the best results. The loose woven construction produces a light flexible fabric ideal for shaped clothing panels. However,
with a loose sett there is a high probability of a projectile sliding between the individual filaments. In addition, a certain amount of bulk is
necessary, as ballistic resistance increases with overall areal density. This necessitates the use of many layers, typically between 5 and 20,
to produce a ballistic pack which will perform adequately. It is necessary to seal the ballistic vest inside a waterproof and light-tight cover, as
the presence of moisture and UV light can reduce the ballistic performance.

3. BALLISTIC FIBERS (Part 1)
[ Volume: 17 Issue: 4 / OCTOBER - DECEMBER 2007 ]
Ahmet ÇAY, Gamze SÜPÜREN, Z. Evrim KANAT, Dr. Tülay GÜLÜMSER, Prof. Dr. Işık TARAKÇIOĞLU (Ege
University Textile Engineering Department)
Ballistic protective clothes are of great importance depending on the rapid
developments in military area. Ballistic protection is one of the main functional
characteristics of military textiles. Ballistic protective clothes protect the body by the
absorption of the kinetic energy of the bullets and shrapnel. High strength fabrics are
used in many industrial areas in connection with ballistic protection such as body
armors, inner parts of plane or vehicles. The main parameters that affect the energy
absorption are the fiber type, fabric construction, tightness and mass per unit area of
the fabric and the number of the fabric layers used in the clothing material. The
fibers used for this purpose should have high tenacity, high modulus and lower
elasticity properties. Recently, para-aramid fibers are the most used fibers for
ballistic protective clothes. Along with para-aramids, high molecular weight
polyethylene fibers also are of importance commercially. Also, there are fibers for
ballistic protection such as wholly aromatic polyester fibers, PBO and PIPD. Also,
carbon nanotubes and spider silk fibers are thought to have great potential
applications for ballistic-resistance materials with their remarkable properties. This
article presents information about the ballistic protection mechanism of textile
materials, the fibers used in those fabrics and the method, which is used to compare
ballistic resistance of textile materials.
Key Words: Ballistic protection, high modulus, energy absorption, para-aramid
fibers, high molecular weight polyethylene fibres