c15 composites c15

7/23/2019 C15 Composites C15

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ISSUES TO ADDRESS...

What are the classes and types of composites?

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Why are composites used instead of metals, ceramics, or polymers?

How do we estimate composite stiness & strength?

What are some typical applications?

CHAP!" 1#$C%P%'(! A!"(A)'


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*

Composites$

++ultiphase material wsigni-cant proportions of ea. phase. atri/$ ++he continuous phase ++Purpose is to$

transfer stress to other phases protect phases from en0ironment

++Classi-cation$ C, CC, PC

ispersed phase$ ++Purpose$ enhance matri/ properties.

C$ increase y, ', creep resist.

CC$ increase 2c

PC$ increase !, y, ', creep resist.

++Classi-cation$ Particle, -3er, structural

metal ceramic polymer

wo0en

-3ers

crosssection0iew

4.#mm

4.#mm"eprinted with permission from. Hull and .W. Clyne,AnIntroduction to CompositeMaterials, *nd ed., Cam3ridge5ni0ersity Press, 6ew 7or8, 199:,;ig. .

!"(6%)%7C)A''(;(CA(%6


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1.

Adapted from ;ig.1:.=, Callister 6e.@;ig. 1:.= iscourtesy Car3oloy'ystems,epartment,

eneral !lectricCompany.

Adapted from ;ig.1:.#, Callister 6e.@;ig. 1:.# iscourtesy oodyear

ire and "u33erCompany.

C%P%'(! '5"B!7$ Particle+(


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=

!lastic modulus, !c, of composites$ ++ two approaches.

Application to other properties$

++ !lectrical conducti0ity, e$ "eplace ! 3y e.

++ hermal conducti0ity, 8$ "eplace ! 3y 8.

;i3er+reinforced 'tructuralParticle+reinforced

ata$Cu matri/wtungstenparticles

4 *4 =4 :4 E4 144

1#4

*44

*#4


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#

Aligned Continuous-3ers

;i3er+reinforcedParticle+reinforced 'tructural

!/amples$

;rom W. ;un8 and !. lan8, FCreepdeformation of 6i+99E, 19EE. 5sed with

permission.

fracturesurface

matri/$ @o @ductile

-3ers$J @6i


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@/

>

Critical -3er length for eecti0e stiening & strengthenin

;i3er+reinforcedParticle+reinforced 'tructural

-3er length> 1#fd

c

-3er diameter

shear strength of

-3er+matri/ interface

-3er strength in tension

!/$ ;or -3erglass, -3er length O 1#mm needed Why? )onger -3ers carry stress more ecientlyD

-3er length> 1# fd

c

'horter, thic8er -3er$

-3er length< 1#fd

c@/

)onger, thinner -3er$

Poorer -3er eciencyetter -3er eciency

Adapted from ;ig.1:.>, Callister 6e.

C%P%'(! '5"B!7$ ;i3er+(((


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!stimate of !cand '$ ++0alid when

++ !lastic modulus in -3er direction$

++' in -3er direction$

eciency factor$++aligned 1$ 2 L 1 @anisotropic++random *$ 2 L


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;i3er +reinforcedParticle+reinforced

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'tructural

'tac8ed and 3onded -3er+reinforced sheets ++ stac8ing seQuence$ e.g., 494 ++ 3ene-t$ 3alanced, in+plane stiness

'andwich panels ++ low density, honeycom3 core ++ 3ene-t$ small weight, large 3ending stiness

Adapted from;ig. 1:.1:,

Callister 6e.

Adapted from ;ig. 1:.1>,Callister 6e. @;ig. 1:.1> isfrom Engineered Materials

andboo!, Bol. 1, Composites, A' (nternational, aterials Par8, %H, 19E>.

C%P%'(! '5"B!7$ 'tructural

honeycom3adhesi0e layer

face sheet


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CCs$ (ncreased toughness PCs$ (ncreased !

Cs$ (ncreased creep resistance

*4


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Composites are classi-ed according to$

++ the matri/ material @CC, C, PC ++ the reinforcement geometry @particles, -3ers, layers.

Composites enhance matri/ properties$ ++ C$ enhance y, ', creep performance

++ CC$ enhance 2c ++ PC$ enhance !, y, ', creep performance

Particulate+reinforced$ ++ !lastic modulus can 3e estimated. ++ Properties are isotropic.

;i3er+reinforced$ ++ !lastic modulus and ' can 3e estimated along -3er dir. ++ Properties can 3e isotropic or anisotropic.

'tructural$ ++ ased on 3uild+up of sandwiches in layered form.

'5A"7


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"eading$

Core Pro3lems$

'elf+help Pro3lems$

4

A66%56C!!6'

c15 composites c15

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