Wood is a natural composite of Cellulose fibres in a matrix of lignin.

Plywood is a man made composite.

ECC is a cement composite.

Concrete itself is a composite.

invented by the Egyptians, approx. 1500 BC

invented by the Romans , approx. 1000 BC

Fibre-reinforced polymer (FRP) is a composite material made of

a polymer matrix reinforced with fibres. The fibres are

usually fibreglass, carbon, or aramid, while the polymer is

usually an epoxy, vinyl ester or polyester thermosetting

plastic. FRPs are commonly used in the aerospace, automotive, marine,

and construction industries.

1. Fibre Process

* Manufacture of fibre fabric.

* Manufacture of fibre preform.

2. Moulding Process

Reinforcing Material

Most Common Matrix Materials

Properties Improved

Glass Fibres

UP, EP, PA, PC, POM, PP, PBT, VE

Strength, Elasticity, heat resistance

Wood Fibres

PE, PP, ABS, HDPE, PLA

Flexural strength, Tensile modulus, Tensile Strength

Carbon and Aramid Fibres

EP, UP, VE, PA

Elasticity, Tensile Strength, compression strength, electrical strength.

Inorganic Particulates

Semi crystalline Thermoplastics, UP

Isotropic shrinkage, abrasion, compression strength

•FRP allows the alignment of the glass fibres of thermoplastics to suit specific design programs. Specifying the orientation of reinforcing fibres can increase the strength and resistance to deformation of the polymer.

•Glass reinforced polymers are strongest and most resistive to deforming forces when the polymers fibres are parallel to the force being exerted, and are weakest when the fibres are perpendicular. Thus this ability is at once both an advantage or a limitation depending on the context of use.

•Weak spots of perpendicular fibres can be used for natural hinges and connections, but can also lead to material failure when production processes fail to properly orient the fibres parallel to expected forces. When forces are exerted perpendicular to the orientation of fibres the strength and elasticity of the polymer is less than the matrix alone.

• In cast resin components made of glass reinforced polymers such as UP and EP, the orientation of fibres can be oriented in two-dimensional and three-dimensional weaves. This means that when forces are possibly perpendicular to one orientation, they are parallel to another orientation; this eliminates the potential for weak spots in the polymer.

Sandwich Composite

Hadid’s Chanel pavilion Construction Mats

•It is best suited for any design program that demands weight savings, precision engineering, finite tolerances, and the simplification of parts in both production and operation. •It can be applied to strengthen the beams, columns and slabs in buildings. It is possible to increase strength of these structural members even after these have been severely damaged due to loading conditions. Beams - I. FRP plates can be pasted to the bottom (generally the tension face)of a beam. This

increases the strength of beam, deflection capacity of beam and stiffness (load required to make unit deflection).

II. FRP strips can be pasted in 'U' shape around the sides and bottom of a beam, resulting in higher shear resistance.

Columns - Can be wrapped with FRP for achieving higher strength. This is called wrapping of columns. The technique works by restraining the lateral expansion of the column. Slabs - FRP strips can be pasted at their bottom (tension face). This will result in better performance, since the tensile resistance of slabs is supplemented by the tensile strength of FRP.

Metal matrix composite (mmc) is a composite material, with one part being metal and the other can be a different metal, ceramic or organic compound.

High strength

High modulus

High toughness and impact properties

Low sensitivity to temperature changes

High surface durability

High electrical conductivity

Particle reinforced composites: reinforcements are SiC,Al2O3,TiC etc

Laminated composites: reinforcements are TiB2,SiC etc

Fiber reinforced composites: reinforcements are B,C,Al2O3+SiO2.

Powder processes

Deposition processes Liquid processes

Solid state processes

Aerospace

Transportation (automotive and railways)

Electronics and thermal management

Filamentary superconducting magnets

Power conduction

Wear resistant materials.

Carbon-Carbon Composites are the woven mesh of Carbon-fibers.

Carbon-Carbon Composites are used for their high strength and modulus of rigidity.

Carbon-Carbon Composites' structure can be tailored to meet requirements.

Carbon-Carbon Composites are light weight material which can withstand temperatures up to 3000°C

Variety of high temperature applications.

• Baffle Heat Shield

• Flexi Heat Shield

Liquid Phase Infiltration

Chemical Vapor Deposition

Preparation of C/C fiber pre-form of desired shape and structure

Liquid pre-cursor : Petroleum pitch/ Phenolic resin/ Coal tar

Pyrolysis (Chemical deposition by heat in absence of O2

It is processed at 540–1000°C under high pressure

Pyrolysis cycle is repeated 3 to 10 times for desired density

Heat Treatment converts amorphous C into crystalline C

Temperature range of treatment :1500-3000°C

Heat treatment increases Modulus of Elasticity and Strength

Preparation of C/C fiber pre-form of desired shape and structure

Densification of the composite by CVD technique

Infiltration from pressurized hydrocarbon gases at 990-1210°C

Gas is pyrolyzed from deposition on fibre surface

Process duration depends on thickness of pre-form

Heat treatment increases Modulus of Elasticity and Strength

This process gives higher strength and modulus of elasticity

Excellent Thermal Shock Resistance

Low Coefficient of Thermal Expansion

High Modulus of Elasticity ( 200 GPa )

High Thermal Conductivity ( 100 W/m*K )

Low Density ( 1830 Kg/m^3 )

High Strength

Low Coefficient of Friction ( in Fiber direction )

Thermal Resistance in non-oxidizing atmosphere

High Abrasion Resistance

High Electrical Conductivity

Non-Brittle Failure

Low oxidation resistance

Reacts with Oxygen at temperature above 490°C

Ceramic coatings

Physical vapor deposition

Plasma spraying

Injecting with inorganic salts , borate & silicate glass.

Replacement of C/C matrix material by Si-C.

High Performance Braking System Refractory Material Hot-Pressed Dies Turbo-Jet Engine Components Heating Elements Missile Nose-Tips Rocket Motor Throats Leading Edges Heat Shields X-Ray Targets

Aramid fibers are a class of heat-resistant and strong synthetic fibers.

The name is aportmanteau of "aromatic polyamide". They are fibers in which the chain molecules are highly oriented along the

fiber axis, so the strength of the chemical bond can be exploited.

General structure of poly-aramide

Marine industry: As the ongoing trend is towards larger, more luxurious motorboats and sailing yachts, and a distinct rise in fast cruising and racing, the demand for greater strength and safety has grown in recent years.

Industrial components: Aramid is used in different kinds of industrial components, like helmets, speaker cones, bottom plates for its high modulus, damage tolerance and strength. It is also used in rods for circuit breakers, where the combination of high modulus and aramid’s dielectric properties offer specific advantages.

aramid Fiber Characteristics No melting point Low flammability Good fabric integrity at elevated temperatures Para-aramid fibers, which have a slightly different molecular structure, also provide outstanding strength to weight properties, high tenacity and high modulus.

Sport and leisure: Different kinds of sporting goods are reinforced with aramid

fibres like tennis rackets, hockey sticks, skis, fishing rods, surf boards and golf shafts. It is also used to build a wide range of vessels, including canoes, kayaks, catamarans and racing boats.

Aramid Fiber Rubber core Packing:Kevlar Packing braided with silicone core is Composite braid, high strength aramid fibers braided around 4 equally spaced silicone silicone rubber cords forming a packings that offers excellent resilience.

Multifaceted and demanding world The industries we are involved in are constantly changing, and manufacturers are facing increasingly stringent market demand. To a major extent , sustainability is the foundation of the composites industry: composite products offer the combination of light-weight and good mechanical properties, often replacing steel or concrete solutions, resulting in fuel savings as well as reduced maintenance costs. Waste aramid can often be reclaimed and recycled for other applications.

bulletproof plate / armor plate (TAT-BP-3):Material: Alumina ceramic composite ofaramid fabric Criteria: NIJ0101.04 level III, resisting 7.62x51mm NATO M80 ball by a M14 rifle, 5.56x45mm SS109 by a M-16 rifle, and 7.62x39 mm MSC by AK-47 rifle. Weight:2.7 kg

PASGT Style Ballistic Helmet:The helmet shape is one that the Army has developed for its Future Force Warrior (FFW) initiative. These helmets, called PASGT helmets, are made using a composite comprising aramid fabric in a thermoset matrix.

Flight suit made of NomexIIIA fire retardant fabric NomexIIIA is a blend of NOMEX, KEVLAR and a static dissipative fiber. It is inherently flame resistant. Material has excellent resistance to mildew, aging abrasion and laundering.

GLASS FIBERS are among the most versatile industrial materials known today. They are readily produced from raw materials, which are available in virtually unlimited supply. All glass fibers described in this article are derived from compositions containing silica. They exhibit useful bulk properties such as hardness, transparency, resistance to chemical attack, stability, and inertness, as well as desirable fiber properties such as strength, flexibility, and stiffness.

Glass-ceramics are polycrystalline material produced through controlled crystallization of base glass. Glass-ceramic materials share many properties with both glasses and ceramics. Glass-ceramics have an amorphous phase and one or more crystalline phases and are produced by a so called "controlled crystallization“. Glass-ceramics have the fabrication advantage of glass as well as special properties of ceramics.

Recycled glass-ceramic tiles

COMMON PHYSICAL PROPERTIES

Fiber Reinforcement

Carbon

fiber Nicalon and

Tyranno fibers

SiC and boron-

monofilament

fibers

Oxide fibers Glass/glass

ceramic fiber Metal Fiber

Carbon fiber reinforced glass SiC-Nicalon fiber reinforcement

Tyranno fiber Silicon Carbide fiber

Aluminum oxide fiber Glass ceramic fiber

The processing of formation of glass ceramics consists of the following steps :

Slurry infiltration and hot-pressing

Tape casting

Sol gel, colloidal routes and electrophoretic deposition

Storage tanks Storage tanks can be made of fiber-glass with capacities up to about 300 tonnes.

The smaller tanks can be made with chopped strand mat cast over a thermoplastic inner tank which acts as a pre-form during construction. Much more reliable tanks are made using woven mat or filament wound fibre with the fibre orientation at right angles to the hoop stress imposed in the side wall by the contents. They tend to be used for chemical storage because the plastic liner (often polypropylene) is resistant to a wide range of strong chemicals. Fiber-glass tanks are also used for septic tanks.

House building Glass reinforced plastics are also used in the house building market for the

production of roofing laminate, door surrounds, over-door canopies, window canopies and dormers, chimneys, coping systems, heads with keystones and sills. The use of fiber-glass for these applications provides for a much faster installation and due to the reduced weight manual handling issues are reduced. With the advent of high volume manufacturing processes it is possible to construct fiber-glass brick effect panels which can be used in the construction of composite housing. These panels can be constructed with the appropriate insulation which reduces heat loss.

Piping GRP and GRE pipe systems can be used for a variety of applications, above and under

the ground. Firewater systems Cooling water systems Drinking water systems Waste water systems/Sewage systems Gas systems

Nanoparticles are the particles whose sizes are less than 100 nm. Hence A nano composite is a multi-phase where one of the phase has one or more dimension less than 100 nm. The mechanical,electrical,thermal,optical,electromagnetic properties of these particles differ markedly from that of the component material. Example abalone shell, bone ,nano composite hydrogel

•In mechanical terms, nanocomposites differ from conventional composite materials due to the exceptionally high surface to volume ratio of the reinforcing phase and/or its exceptionally high aspect ratio. • The reinforcing material can be made up of particles (e.g. minerals), sheets (e.g. exfoliated clay stacks) or fibres (e.g. carbon nanotubes or electro spun fibres). • The area of the interface between the matrix and reinforcement phase(s) is typically an order of magnitude greater than for conventional composite materials.

• This large amount of reinforcement surface area means that a relatively small amount of nano scale reinforcement can have an observable effect on the macro scale properties of the composite. For example, adding carbon nanotubes improves the electrical and Thermal conductivity . •Other kinds of nanoparticulates may result in enhanced optical properties Dielectric properties , heat resistance or mechanical properties such as stiffness, strength and resistance to wear and damage. In general, the nano reinforcement is dispersed into the matrix during processing.

Epoxy layered silicate nano composites

• Ceramic matrix nanocomposites : In this group ceramic is the main constituent (ceramic is generally a compound of oxides ,nitrides ,borides ,silicides . • Metal matrix nanocomposites : they can also be defined as reinforced metal Matrix composites example carbon nano tube metal matrix • polymer matrix nanocomposites :In the simplest case, appropriately adding nanoparticulates to a polymer matrix can enhance its performance

Polymer glass matrix fiber

Carbon nanotubes

Ceramic matrix (Sio and al)

The Nanocomposites 2000 conference has revealed clearly the property advantages that nanomaterial additives can provide in comparison to both their conventional filler counterparts and base polymer. Properties which have been shown to undergo substantial improvements include: • Mechanical properties e.g. strength, modulus and dimensional stability • Decreased permeability to gases, water and hydrocarbons • Thermal stability and heat distortion temperature • Flame retardancy and reduced smoke emissions • Chemical resistance • Surface appearance • Electrical conductivity • Optical clarity in comparison to conventionally filled polymers

To date one of the few disadvantages associated with nanoparticle incorporation has concerned toughness and impact performance. Some of the data presented has suggested that nanoclay modification of

polymers such as polyamides, could reduce impact performance.

Clearly this is an issue which would require consideration for applications where impact loading events are likely. In addition, further research will be necessary to, for example, develop a better understanding of formulation/structure/property relationships, better routes to platelet exfoliation and dispersion etc.

Light weight

High strength and stiffness

Corrosion resistance (long life)

Design and formulation flexibility

Fatigue resistance

Good damping characteristics

Low thermal conductivity

Unitized structure/Part consolidation

High impact strength

Radar Transparent

Durability

Corrosion Resistance- Composites products provide long-term resistance to severe chemical and temperature environments. Composites are the material of choice for outdoor exposure, chemical handling applications, and severe environment service. Light Weight - Composites are light in weight, compared to most woods and metals. Their lightness is important in automobiles and aircraft, for example, where less weight means better fuel efficiency (more miles to the gallon).

Design flexibility- Composites have an advantage over other materials because they can be molded into complex shapes at relatively low cost. This gives designers the freedom to create any shape or configuration. Boats are a good example of the success of composites.

Low Relative Investment- One reason the composites industry has been successful is because of the low relative investment in setting-up a composites manufacturing facility. This has resulted in many creative and innovative companies in the field.

Durability- Composite products and structures have an exceedingly long life span. Coupled with low maintenance requirements, the longevity of composites is a benefit in critical applications. In a half-century of composites development, well-designed composite structures have yet to wear out.

Higher Specific Strength (strength-to-weight ratio)- Composites have a higher specific strength than many other materials. A distinct advantage of composites over other materials is the ability to use many combinations of resins and reinforcements, and therefore custom tailor the mechanical and physical properties of a structure.

.

Reinforcing fibres give composites the attributes of high strength and stiffness which in the industrial arena translates to high performance. These fibres are surrounded by a choice of polymers that act as a support system, transferring load between fibres and protecting the fibres from the operating environment. Fibre/resin combinations have significantly lower weight densities when compared to steel and concrete. This means excellent strength and stiffness ratios-to-weight ratios. A Multilayer Composite Pipe combines the advantages of metal and plastic pipes and eliminates the disadvantages of both materials at the same time. The aluminium core is absolutely diffusion tight and prevents oxygen or gases from permeating into the pipe. It compensates and reduces snap-back forces and heat expansion with changes in temperature.

Multilayer Composite pipe

52

Properties in composites vary from point to point in the material. Most engineering structural materials are homogeneous.

Composites are heterogeneous

Composites are highly anisotropic

The strength in composites varies as the direction along which we measure changes (most engineering structural materials are isotropic). As a result, all other properties such as, stiffness, thermal expansion, thermal and electrical conductivity and creep resistance are also anisotropic. The relationship between stress and strain (force and deformation) is much more complicated than in isotropic materials.

Highly Prone to Chemical Paints Also, chemical paint strippers are very harmful to composites, and must not be used on them. If paint needs to be removed from composites, only mechanical methods are allowed, such as gentle grit blasting or sanding. Many expensive composite parts have been ruined by the use of paint stripper, and such damage is generally not repairable.

The most important disadvantage is the lack of visual proof of damage. Composites respond differently from other structural materials to impact, and there is often no obvious sign of damage. In a composite structure, a low energy impact, such as a bump or a tool drop, may not leave any visible sign of the impact on the surface. Underneath the impact site there may be extensive delaminations, spreading in a cone-shaped area from the impact location. The damage on the backside of the structure can be significant and extensive, but it may be hidden from view Impact energy affects the visibility, as well as the severity, of damage in composite structures. High and medium energy impacts, while severe, are easy to detect. Low energy impacts can easily cause hidden damage.