Defense Textiles
The Defense textile is grouped into two
categories:
Textile used in Defense systems and weapons:
Includes tents, shelters, parachutes, harness cords, composites and Tarpaulins.
Protective clothing and individual equipment:
Includes ballistic protective vests and helmets, battle dress and uniform,
chemical protective uniform, field packs, equipment belts, suspenders, mountain
climbing ropes etc.
Tent Fabrics:
Requirements:
- The fabrics should be resistant to dimensional changes under wet conditions
- Mobility is an important criteria, should posses low weight. And there should be ease of erection plus deployment
- It should offer environmental protection, chemical / biological infrared and radar avoidance techniques, should be waterproof
- It should be rot and mild-dew resistant and non flammable
Material Requirements:
Duck fabrics are made of 100% cotton with variety of fire, weather;
water and mild-dew resistant treatment are used for tents. Synthetic and
blended yarns are also used for tent fabrics.
Textile used in Parachute:
A Parachute is an apparatus used to protect or slow down
the progress as a person or an object fall down or moves through air. It is
mainly used by person dropped from airplane. It is also use for following
purposes:
- Accurate bomb dropping, controlled decent of flares
- Aerial delivery of materials / cargo, heavy equipments etc
- Slow down the speed of aircrafts during landings
- It is also use as air decelerator for arresting high speed of fighter aircrafts during landing to reduce wear and tear of the braking mechanism of the aircrafts
- Parachute components: A parachute consists of four main components namely a parachute canopy, rip cords, harness and the suspension lines.
Parachute Fabrics:
They are made from thin, light weight and the ropes
Fabric is termed as ‘Canopy’ or the ‘Wing’ and the ropes
are termed as ‘lines’
Basic properties of parachute fabrics: The most
significant properties are strength, weight and air porosity and they are
closely inter- related and change in any of these properties would impact each
other.
Parachute canopy Fabrics requirements:
- Fabric thickness should be less so that it can be folded
- Fabrics should have high strength to weight ratio
- Air permeability is significant aspect as it determines the rate of descent
- Made from high tensile nylon multi- filament yarns
- Made from woven ripstop weave fabrics from 32 to 200 deniers with GSM of around 35
- Tapes, webbings and harness are made of high tensile nylon of 210 to 840 denier range
Protective clothing:
Requirements of military protective clothing increased
tremendously with the development of biological, chemical, thermonuclear and
more effective fragmentation weapons, etc
The purposes of military protective clothing are as
follows:
The most important purpose of all is to maximize
survivability
Sustainability and combat effectiveness of individual
solider system against extreme weather conditions, ballistic, nuclear ,
chemical warfare.
Requirements for advanced integrated combat clothing system:
Physical Requirement: the clothing should be durable and
resistant to extreme weather conditions, should have good tensile strength, and
tear strength and good abrasion resistance.
Physiological Requirement : The clothing must be easy to
wear and should have low weight and should be comfortable
Battlefield requirements: Ballistic protection, the
fabric must be such that it should be flame resistant, resistant to chemical
and biological agents, good camouflage properties.
Other requirements:
These properties include resistance to propellant flues, acids, liquefies
gases.
Ballistic protection:
The main purpose of ballistic protection is to offer
protection to the body and eyes of the solider against projectiles with various
shape, size and impact velocity.
Principle:
Each layer of though fabric reduces the impact of the
projectile. In each layer, impact energy from the from the struck fibers is
absorbed and dispersed to other fibers in the weave of the fabric
Plain balanced woven fabric I preferred to maximize the
number of crossover points.
Fibers and Fabric
used:
The most widely used are aramid, Kevlar by Dupont, Dynema
by DSM Netherlands, Technora by Teijin of Japan
Kevlar is up to 5 times stronger than steel
Spectra patent gel- spinning process, high tensile
strength and good chemical resistance
Dynema, is made up of ultra- high molecule weight
polyethylene produced by gel- spinning process
Chemical and Biological
protection:
The purpose is to isolate parts of body from direct
contact with harmful chemicals.
Applications: It protect farmers from insecticides, fire
fighters from chemical substance etc, truck drivers from toxic / flammable
material during loading or unloading.
Material used: Porous fabrics for particulate protection
e.g. spun bonded olefins, hydroentangled spun lace, cellulosic materials and
spun bonded- melt blown- spun bonded composites. Coated / laminate fabrics for
liquid and gas protection.
Important Parameters: Break through time, degradation,
permeation and penetration.
Flame Retardant Fabrics:
Designed to resist ignition and self extinguished when
ignited. It can be achieved in two ways. Firstly, by using inherently flame
resistant materials and fibers Aramid, PBI (polybenzimidazole) and PFR rayon.
Secondly, by using special treatment of fibers and fabrics.
The requirements are that the higher LOI which ensures
better flame resistance and Atmospheric oxygen content 16%
Testing :
- 45 degrees Celsius test, in which sample is exposed to one second ignition and time to burn 5 inches measured.
- Vertical flame resistance test: 12 inches long sample is suspended vertically to controlled flame for about 12 seconds
Applications: It is used in the production of
firefighting uniforms, furniture manufacturing airline seats.
Camouflage Fabrics:
Camouflage fabrics are required for military uniforms
equipments and tents which helps to reduce visibility to sensor threats such as
image, radar, thermal imagers and multi spectral sensors.
- They provide protection against detection by blending in terrain.
- Camouflage colors
- Snowy areas : white color garment
- Deserts : Different tone of brown
- Subtropical background: black, brown and green
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