Composites

7/17/2019 Composites

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Metals

Polymers

Ceramics

Composites

Chapter 1 Summary:



Composites consist of:

1. Combination of two or more materials – Composite = matrix + fiber (filler):

Matrix:

material component that surroun!s the fiber.

"sually a ductile, or tough, material w/ low density

Strength usually = 1/10 (or less) than that of fiber

#xamples inclu!e: thermoplastic or thermoset

$hermoset most common (epoxy% pheneolic)

Ser&es to hol! the fiber (filler) in a fa&orable orientation.

'iber aa reinforcin material aa 'iller:

Materials that are strong with low densities

#xamples inclu!e lass% carbon or particles.

*. esine! to !isplay a combination of the best characteristics of each

material i.e. fiberlass ac,uires strenth from lass an! flexibility from the

polymer.

-. Matrix an! filler bon!e! toether (a!hesi&e) or mechanically loce!toether



/here are composites

use!000000

C'P 2 carbon

fiber reinforce!

composite.

3'P 2

lass fiber

reinforce!

composite



#nineerin applications 2 4erospace

2 4utomobile

2 Pressure &essel an! pipes 4ny place where hih performance materials are !esire!

Composites in in!ustry

$urret Shiel! 5n!ustrial

Sprin

Me!ical $able

6ullet proof

shiel!s

www.composiflex.com



4!&antaes: 2 High strength to weight ratio (low density high tensile strength) or high

specific strength ratio 10!0 H"S spec strength = 1 (#$ in) %raphite/#po&y, spec strength = ' (#$ in)

2 High creep resistance 2 High tensile strength at eleated temperatures 2 High toughness 2 %enerally perform better than steel or aluminum in applications where

cyclic loads are encountered leading to potential fatigue failure (iehelicopter blades)

2 *mpact loads or ibration + composites can be specially formulated withhigh toughness and high damping to reduce these load inputs

2 Some composites can hae much higher wear resistance than metals 2 orrosion resistance 2 -imensional changes due to temp changes can be much less

2 .nisotropic + bidirectional properties can be design adantage (iehelicopter blades)

7ature of Composites:



isa!&antaes (or limitations):

2 Material costs

2 abrication/ manufacturing difficulties

2 "epair can be difficult

2 ider range of ariability (statistical spread)

2 2perating temperature can be an issue for polymericmatri& (ie '00 ) 3ess an issue for metal matri&

(!,400 )

2 5roperties nonisotropic ma6es design difficult

#&ample + ideo test in line w/ fibers 107 stronger s fibers

oriented at an angle

2 *nspection and testing typically more comple&




lassification of omposite Materials by Matri

Ceramic

(Cermets)

Metal

Polymer

(resin)

1. Metal matrix

*. Ceramic matrix

-. Polymer (esin) matrix

Most common 2 also

calle! fiber reinforce!

polymer



Classification of Composite

Materials by Matrix:

• Polymer matrix composites or FiberReinforced Polymer (FRP) 2 'ibers enerally lass% carbon or e&lar

2 Matric can be: $hermoplastics: P#% 7ylon% PS% PP% PC% P8C

$hermosets: #poxy% polyester% phenolics

2 9a&e hih strenth an! stiffness to weiht ratio

2 4erospace% sportin oo!s marine 2 #xamples: 3'P aa fiberlass (polyester or epoxy

an! lass)% C'P (polyester or epoxy an! carbon)%'P (polyester or epoxy an! eflar)

'iller = 0 Matrix = 0



;ayere! Composites

oordinate System;amina 2 1%*%-

;aminate 2 x%y%<



anin of Most Common

'ibers for 'P

5roperty %lass arbon 9elar

Strenth /orst 5n between 6est

Stiffness /orst 6est 5n 2 between

Cost 6est /orst 5n 2 between

/eiht /orst 6est 5nbetween



Manufacturin 'P (see &i!eo)

9an! layup (http:>>www.youtube.com>watch0

&=?3,xnahwb@list=P;A'CB''*11*D-1*@in!ex=*

'ilament win!in or Pultrusion (http:>>www.youtube.com>watch0&=EMo97F6b?G

esin $ransfer (or) 5nHection Mol!in ($M)

http:>>www.ccomposites.com>

http:>>www.scale!.com>in!ex.html

http://www.scaled.com/projects/ttop/press_release.pdf





•Metal matrix composites (MMC):

2 Metal matrix: 4l% $i% M% 'e% Cu% 7i

2 #xample: 4lSiC (silicon carbi!e)

2 #xample: 4l4l*I- (aluminum oxi!e)

2 9ih strenth% hih stiffness% abrasion

resistance% !imensional stability% hih

temperature an! touhness.

= matrix





Ceramic matrix composites

(CMC):

2 Silicon carbi!esilicon carbi!e (SiCSiC)

2 Same material both matrix an! filler 6"$ filler

!ifferent form such as whicers% choppe!

fibers or stran!s to achie&e preferre!properties.

= matrix



:he strength of the composite depends

primarily on the amount, arrangementand type of fiber (or particle)reinforcement in the resin

:ypically, the higher the reinforcementcontent, the greater the strength *nsome cases, glass fibers are combinedwith other fibers, such as carbon or

aramid (9elar!; and 9elar<;), tocreate a hybrid composite thatcombines the properties of more than

one reinforcing material




lassification of omposite

by iller :ype8

2 5articlereinforced composites

2 iberreinforced composites 2 Structural composites



5article "einforced omposites8

5articles used for reinforcing include8 2 ceramics and glasses such as small mineral particles, 2 metal particles such as aluminum, 2 and amorphous materials, including polymers and carbon blac6

5articles are used to increase the modulus of the matri&, to decreasethe permeability of the matri&, or to decrease the ductility of the

matri& 5article reinforced composites support higher tensile, compressie

and shear stresses 5articles are also used to produce ine&pensie composites #&amples8

2 automobile tire which has carbon blac6 particles in a matri& of elastomeric

polymer 2 spheroidi>ed steel where cementite is transformed into a spherical shapewhich improes the machinability of the material

2 concrete where the aggregtes ( sand and grael) are the particles andcement is the matri&



igure 1 #&amples for particlereinforced composites

(Spheroidi>ed steel and automobile tire)



iberreinforced omposites8

"einforcing fibers can be made of metals, ceramics, glasses, or polymers thathae been turned into graphite and 6nown as carbon fibers ibers increase themodulus of the matri& material :he strong coalent bonds along the fiber?slength gies them a ery high modulus in this direction because to brea6 ore&tend the fiber the bonds must also be bro6en or moed ibers are difficult toprocess into composites which ma6es fiberreinforced composites relatielye&pensie iberreinforced composites are used in some of the most

adanced, and therefore most e&pensie, sports e@uipment, such as a timetrialracing bicycle frame which consists of carbon fibers in a thermoset polymermatri& Aody parts of race cars and some automobiles are composites made ofglass fibers (or fiberglass) in a thermoset matri&

:he arrangement or orientation of the fibers relatie to one another, the fiberconcentration, and the distribution all hae a significant influence on thestrength and other properties of fiberreinforced composites .pplicationsinoling totally multidirectional applied stresses normally use discontinuous

fibers, which are randomly oriented in the matri& material onsideration oforientation and fiber length for a particular composites depends on the leeland nature of the applied stress as well as fabrication cost 5roduction rates forshortfiber composites (both aligned and randomly oriented) are rapid, andintricate shapes can be formed which are not possible with continuous fiberreinforcement



Bote8 iber composite

manufacturers often rotate layers of

fibers to aoid directional ariations

in the modulus



$he mo!ulus of the entire composite% matrix plus reinforcer%is o&erne! by the rule of

mixtures:

Stiff an! Stron

Soft an! /eaSee case stu!y at en!



Structural omposites8

:he properties of structural composites

depend on8

2 onstituents

2 %eometrical design




ommon structural composite types are8

2 3aminar8 *s composed of twodimensional sheets

or panels that hae a preferred high strength

direction such as is found in wood andcontinuous and aligned fiberreinforced plastics

:he layers are stac6ed and cemented together

such that the orientation of the highstrength

direction aries with each successie layer 2ne

e&ample of a relatiely comple& structure ismodern s6i and another e&ample is plywood




ommon structural composite types are8 2 Sandwich 5anels8 onsist of two strong outer

sheets which are called face sheets and may bemade of aluminum alloys, fiber reinforced

plastics, titanium alloys, steel ace sheets carrymost of the loading and stresses ore may be ahoneycomb structure which has less density thanthe face sheets and resists perpendicularstresses and proides shear rigidity Sandwichpanels can be used in ariety of applicationswhich include roofs, floors, walls of buildings andin aircraft, for wings, fuselage and tailplane s6ins

Show example (ref: bh

userJs conference)





Material property charts: mo!ulus !ensity

K.1

1K

1

1KK

Metals

Polymers

#lastomers

Ceramics

/oo!s

Composites

'oams

K.K1

1KKK

1KKK.1 1 1K

ensity (M>m-)

G o u n J s m o ! u l u

s # %

( 3 P a )









7eat ;ins

http:>>www.scale!.com>in!ex.html

http:>>composite.about.com>i>!ynamic>offsite.htm0site=httpL-4L*'L*'poisson.me.!al.ca

L*'esin?proHsL*'AB?ADL*'compositeL*'

http:>>en.wiipe!ia.or>wii>Composite?material

http:>>www.youtube.com>watch0&=?3,xnahwb@list=P;A'CB''*11*D-1*@in!ex=*

#M457573 S;5#S #'##7C# I7;G 2 7o nee! to

print out

3oo! manufacturin

&i!eos

http://www.scaled.com/index.html

http://composite.about.com/gi/dynamic/offsite.htm?site=http%3A%2F%2Fpoisson.me.dal.ca%2FDesign_projs%2F96_97%2Fcomposite%2F


http://en.wikipedia.org/wiki/Composite_material

http://en.wikipedia.org/wiki/Composite_material



http://www.scaled.com/index.html



2rthotropic material data re@uires nine alues to be

fully described

2 $hree GounJs mo!uli (#x%#y%#<)

2 $hree Poissons ratio(&xy% &y<%&x<)

2 $hree Shear mo!uli (3xy% 3y<% 3x<)

Case Stu!y: 3eneratin Properties for '#

4nalysis of Composites



$este! D specimens 2 - !ifferent &olume fractions.

$ensile test at K %AK %1K off axis⁰ ⁰ ⁰

- point ben! test at K an! AK⁰ ⁰

2 4pplie! o&er 1K strain aes

2 4pplie! 1*K tabs for tensile specimens

ProHect wor complete!

1K !erees

off y axis

1 of each

1 of each



esearche! Mechanics of Composites

2 $o obtain theoretical !ata we use! the ule ofMixtures

/hy the rule of mixtures0

ProHect wor complete!

6eie = esin

6lac = 'ibers

/hite = 8oi!s



%rafil C<400 carbon fiber tows 2 $ensile tow strenth σ = DKK si

2 $ensile Μo!ulus # = -E%KKK si

2 ensity ρ = .KB lbm>in-

Bewport C01 #po&y "esin

2 $ensile strenth σ = -KK psi

2 $ensile Μo!ulus # = EBK si

2 Shear Mo!ulus 3 = KK si

2 ensity ρ = .KEE1 lbm>in-

$ypical Material Properties



' = 'ibers

= esin

C = Composites

8' = 'iber &olume fraction ensity

;onitu!inal Mo!ulus

$rans&erse Mo!ulus

ule of Mixtures (cont.)

6eie = esin6lac = 'ibers

/hite = 8oi!s



5n Plane Shear Mo!ulus

MaHor PoissonJs ratio

;onitu!inal Strenth




$his i&es :

2 #1% #*% 31* @ ν1*

$he remainin missin &alues can be

approximate! usin an assumption of trans&erseisotropy (Mil9an!boo1D)

2 #-=#*% 3*1=3-*% ν*1= ν-*

Iut of plane Shear Mo!ulus

2 3*1=(#*)>*(1+ ν*1) #stimate or measure ν*1




'in!in 8olume 'raction

Composite Specimen in 7itric 4ci! eterminin mass of fibers

after aci! bath

'ibers in booner



Mo!ulus 6ase! on 'iber 4nle

See material summary sheet



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Composites