Composites Small

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COMPOSITE MATERIALS

Matrix and Resin


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COMPOSITE MATERIALS Are a combination of two or more elements that create a material with different characteristics than

the elements that compose it.

Composites fall within 3 categories:

1. Polymer Matrix composites (PMC’s)

2. Metal Matrix Composites (MMC’s)

3. Ceramic Matrix Composites (CMC’s)

Carbon Nanotubes

Carbon Fiber

Ceramic Composite

They are commonly composed of a main mass referred to as amatrix and strengthening agent that acts as a binder referred to as aresin. Other materials can be applied to the matrix in order to providemore stability in the composite. These layers create an envelopearound the matrix completely enclosing it and creating a much stron-

ger material.


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These are the most commonly found type of composites. They areusually know as fiber reinforced polymers (FRP). They consist of afiber like carbon, glass and aramid as the reinforcement and a poly-mer based resin as the matrix.

They have the following characteristics:-Fiber properties-Resin properties-Ratio of fiber to resin-Geometry and orientation of the fibers.

More commonly found in the auto-motive industry. They use a aluminumcore as the matrix and are reinforced withsilicon carbide fibers.

Are commonly used in high temperature environments. They useceramics as the matrix and are reinforced withsilicon carbide fibers and boron nitride.

1. Polymer Matrix composites (PMC’s)

2. Metal Matrix Composites (MMC’s)

3. Ceramic Matrix Composites (CMC’s) Carbon Nanotubes

Carbon Fiber

Ceramic Composite


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RESINS They provide strength and adhesion capabilities to a composite material. They can also act as the

matrix in a fiber reinforced material.

1. Have good mechanical properties2. Good adhesion3. Toughness4. And posses environmental degradation

The most common types of resins found are:• Polyester resins: do not require pressure to adhere to the matrix.• Vinylester: have higher resistance to water.• Epoxy: has great mechanical properties as well as great adhesion strength.


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RESIN SYSTEMS Polyesters Advantages:

Easy to useLowest cost of resins Available ($1.50-3/kg)

Disadvantages:Only moderate mechanicalproperties

High styrene emissions inopen mouldsHigh cure shrinkage Limitedrange of working times

Vinylesters Advantages:

Very high chemical/environ-mental resistanceHigher mechanical properties

than polyesters

Disadvantages:Post cure generally required

for high properties High sty-rene content jHigher cost than polyesters($3-4.50/kg)High cure shrinkage

Epoxies Advantages:

High mechanical and thermalpropertiesHigh water resistanceLong working times available

Temperature resistance canbe I to 140°C wet / 220°Cdry

Low cure shrinkage

Disadvantages:Post cure generally requiredfor high propertiesHigh styrene content j

Higher cost than polyesters($3-4.50/kg)High cure shrinkageDisadvantages:More expensive than vinylest-ers ($4.50-22.50/kg)Critical mixingCorrosive handling


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FIBERS AND MATRIXES


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By blending quarry products (sand, kaolin, limestone, ) at1,600°C, liquid glass is formed. The liquid is passed through mi-

cro-fine bushings and simultaneously cooled to produce glass fiberfilaments from 5-24m in diameter. The filaments are drawn togeth-er into a strand (closely associated) or roving (loosely associated),and coated with a “size” to provide filament cohesion and protect

the glass from abrasion.

E-glass (electrical): lower alkali content and stronger than A glass(alkali). Good tensile and compressive strength and stiffness, goodelectrical properties and relatively low cost, but impact resistancerelatively poor. Depending on the type of E glass the price rangesfrom about $1.50-3/kg. E-glass is the most common form of rein-forcing fiber used in polymer matrix composites.

3 Types:

C-glass (chemical): best resistance to chemical attack. Mainly

used in the form of surface tissue in the outer layer of laminatesused in chemical and water pipes and tanks.

Rovings: a loosely associated bundle of untwisted filaments orstrands. Each filament diameter in a roving is the same, and isusually between 13-24m. Rovings also have varying weights and

the tex range is usually between 300 and 4800. Where filamentsare gathered together directly after the melting process, the resul-

tant fiber bundle is known as a direct roving.

FIBERS AND MATRIXES

FIBERGLASS


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Aramid fiber is a man-made organic polymer (an aromatic polyam-ide) produced by spinning a solid fiber from a liquid chemical

blend. The bright golden yellow filaments produced can have arange of properties, but all have high strength and low densitygiving very high specific strength. All grades have good resistance

to impact, and lower modulus grades are used extensively in ballis- tic applications. Compressive strength, however, is only similar to that of E glass.

Carbon fiber is produced by the controlled oxidation, carbonizationand graphitisation of carbon-rich organic precursors which arealready in fiber form. The most common precursor is polyacryloni-

trile (PAN), because it gives the best carbon fiber properties, butfibers can also be made from pitch or cellulose. Variation of the

graphitisation process produces either high strength fibers (@~2,600°C) or high modulus fibers (@ ~3,000°C) with other typesin between. Once formed, the carbon fiber has a surface treat-ment applied to improve matrix bonding and chemical sizing whichserves to protect it during handling.

FIBERS AND MATRIXES

ARAMID FIBER

CARBON FIBER


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CORE MATERIALS

Polyurethane foam

Engineering theory shows that the flexural stiffness of any panel isproportional to the cube of its thickness. The purpose of a core in

a composite laminate is therefore to increase the laminates stiff-ness by effectively 'thickening' it with a low-density core material. This can provide a dramatic increase in stiffness for very little addi- tional weight.

PVC foams are widely used core materials in the marine, surface transport, aerospace, and windenergy industries due to their consistent density, high moisture resistance, and excellent physical prop-erties.


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Honeycomb cores are available in a variety of materials for sandwich structures.

CORE MATERIALS Honeycomb cores

Wood cores Other, coremat and spheretex

Paper core Aluminum core


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OTHER COMPOSITES Large particles

Concrete


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Using carbon fiber reinforced

filament for 3D printing.

Thinner structures allow for

more opportunities to enable

the facade to accommodate

an array of systems.

Opportunity to create a

composite smart materials.

E.G. Carbon fiber and

photovoltaic cells.

SMART APPLICATIONS


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Carbon fiber is produced by the controlled oxidation, carbonization and graphitisation ofcarbon-rich organic precursors which are already in fiber form. The most common precur-

sor is polyacrylonitrile (PAN), because it gives the best carbon fiber properties, but fiberscan also be made from pitch or cellulose. Variation of the graphitisation process produceseither high strength fibers (@ ~2,600°C) or high modulus fibers (@ ~3,000°C) with other

types in between. Once formed, the carbon fiber has a surface treatment applied to im-prove matrix bonding and chemical sizing which serves to protect it during handling.

CONTINUOUS TOW

CHOPPED

MILLED

FABRIC

WOVEN FABRICS

FELT

CARBON FIBER

TYPES OF FIBER


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CARBON FIBER CHARACTERISTICS


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`Carbon fiber is formed the same way as fiberglass. Epoxy orpolyester resin is used as the binding agent. Since carbon fiber isas easy to apply as fiberglass this composite becomes a highly

versatile material. Its hight strength to weight ratio make it ideal forintense structural use. Its ability to be milled allows it to be used in3D printing industries.

https://youtu.be/hjErH4_1fks

https://youtu.be/RiPQpiE4_qY 3D printing

Automotive

APPLICATIONSCARBON FIBER


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CARBON FIBER GradesCarbon fiber is the result of heating polyacrylanitrile fiber to intense temperatures that remove

the majority of its elements except the carbon. This process is called pirolyzing process. The

resulting fiber after this process has the tensile modulus of 33 million pounds per square inch(MSI), this is also referred as the standard modulus. By processing the strand even further this

will yield a higher tensile modulus equal to 42 MSI. This intermediate modulus creates smallerstrands than the standard allowing for more fibers to be packed in thus creating higher stiff-ness. The high modulus fiber are the result of heating the fibers even more. This results in a

tensile modulus of 55 MSI and fibers much more denser and smaller than the standard modu-

lus which makes the fibers more brittle and fairly more expensive.

Fibers are sold in bundles designated by a (K) which signfies thousands of fibers. The mostcommon denominations are: 1K, 3K, 6K, 12K, 24K, 50K. These bundles are then used for

weaving fabrics that can be later be applied in numerous applciations.


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http://zoltek.com/products/panex-35/

http://calfeedesign.com/tech-papers/grades-of-carbon-fiber/

Addington, Michelle and Schodek,Daniel, "Smart Materials and New Technologies For Architecture and

Design Professions", Massachusetts: Architectural Press, 2005.

Buckley, John D., and Danny Dale Edie. Carbon-carbon materials and composites. Vol. 1254. William

Andrew, 1993.

Lee, Henry, and Kris Neville. "Handbook of epoxy resins." (1967).

https://books.google.com/books?hl=en&lr=&id=BRcdDu4bUhMC&oi=fnd&pg=PR13&dq=composite

+materials&ots=E2D4izG16Y&sig=O4XOB46nsHz2o5F2vEbVJqY6q30#v=onepage&q=composite

%20materials&f=false

http://www.som.com/news/worlds_largest_3d-

printed_polymer_building_will_be_shown_at_international_builders_show

RESOURCES


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